136 results on '"Marie-Christine Prévost"'
Search Results
2. Reprogramming neutral lipid metabolism in mouse dendritic leucocytes hosting live Leishmania amazonensis amastigotes.
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Hervé Lecoeur, Emilie Giraud, Marie-Christine Prévost, Geneviève Milon, and Thierry Lang
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Arctic medicine. Tropical medicine ,RC955-962 ,Public aspects of medicine ,RA1-1270 - Abstract
BACKGROUND: After loading with live Leishmania (L) amazonensis amastigotes, mouse myeloid dendritic leucocytes/DLs are known to undergo reprogramming of their immune functions. In the study reported here, we investigated whether the presence of live L. amazonensis amastigotes in mouse bone marrow-derived DLs is able to trigger re-programming of DL lipid, and particularly neutral lipid metabolism. METHODOLOGY/PRINCIPAL FINDINGS: Affymetrix-based transcriptional profiles were determined in C57BL/6 and DBA/2 mouse bone marrow-derived DLs that had been sorted from cultures exposed or not to live L. amazonensis amastigotes. This showed that live amastigote-hosting DLs exhibited a coordinated increase in: (i) long-chain fatty acids (LCFA) and cholesterol uptake/transport, (ii) LCFA and cholesterol (re)-esterification to triacyl-sn-glycerol (TAG) and cholesteryl esters (CE), respectively. As these neutral lipids are known to make up the lipid body (LB) core, oleic acid was added to DL cultures and LB accumulation was compared in live amastigote-hosting versus amastigote-free DLs by epi-fluorescence and transmission electron microscopy. This showed that LBs were both significantly larger and more numerous in live amastigote-hosting mouse dendritic leucocytes. Moreover, many of the larger LB showed intimate contact with the membrane of the parasitophorous vacuoles hosting the live L. amazonensis amastigotes. CONCLUSIONS/SIGNIFICANCE: As leucocyte LBs are known to be more than simple neutral lipid repositories, we set about addressing two related questions. Could LBs provide lipids to live amastigotes hosted within the DL parasitophorous vacuole and also deliver? Could LBs impact either directly or indirectly on the persistence of L. amazonensis amastigotes in rodent skin?
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- 2013
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3. A natural system of chromosome transfer in Yersinia pseudotuberculosis.
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Biliana Lesic, Mohamed Zouine, Magaly Ducos-Galand, Christèle Huon, Marie-Laure Rosso, Marie-Christine Prévost, Didier Mazel, and Elisabeth Carniel
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Genetics ,QH426-470 - Abstract
The High Pathogenicity Island of Yersinia pseudotuberculosis IP32637 was previously shown to be horizontally transferable as part of a large chromosomal segment. We demonstrate here that at low temperature other chromosomal loci, as well as a non-mobilizable plasmid (pUC4K), are also transferable. This transfer, designated GDT4 (Generalized DNA Transfer at 4°C), required the presence of an IP32637 endogenous plasmid (pGDT4) that carries several mobile genetic elements and a conjugation machinery. We established that cure of this plasmid or inactivation of its sex pilus fully abrogates this process. Analysis of the mobilized pUC4K recovered from transconjugants revealed the insertion of one of the pGDT4-borne ISs, designated ISYps1, at different sites on the transferred plasmid molecules. This IS belongs to the IS6 family, which moves by replicative transposition, and thus could drive the formation of cointegrates between pGDT4 and the host chromosome and could mediate the transfer of chromosomal regions in an Hfr-like manner. In support of this model, we show that a suicide plasmid carrying ISYps1 is able to integrate itself, flanked by ISYps1 copies, at multiple locations into the Escherichia coli chromosome. Furthermore, we demonstrate the formation of RecA-independent cointegrates between the ISYps1-harboring plasmid and an ISYps1-free replicon, leading to the passive transfer of the non-conjugative plasmid. We thus demonstrate here a natural mechanism of horizontal gene exchange, which is less constrained and more powerful than the classical Hfr mechanism, as it only requires the presence of an IS6-type element on a conjugative replicon to drive the horizontal transfer of any large block of plasmid or chromosomal DNA. This natural mechanism of chromosome transfer, which occurs under conditions mimicking those found in the environment, may thus play a significant role in bacterial evolution, pathogenesis, and adaptation to new ecological niches.
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- 2012
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4. Is adipose tissue a place for Mycobacterium tuberculosis persistence?
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Olivier Neyrolles, Rogelio Hernández-Pando, France Pietri-Rouxel, Paul Fornès, Ludovic Tailleux, Jorge Alberto Barrios Payán, Elisabeth Pivert, Yann Bordat, Diane Aguilar, Marie-Christine Prévost, Caroline Petit, and Brigitte Gicquel
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Medicine ,Science - Abstract
BackgroundMycobacterium tuberculosis, the etiological agent of tuberculosis (TB), has the ability to persist in its human host for exceptionally long periods of time. However, little is known about the location of the bacilli in latently infected individuals. Long-term mycobacterial persistence in the lungs has been reported, but this may not sufficiently account for strictly extra-pulmonary TB, which represents 10-15% of the reactivation cases.Methodology/principal findingsWe applied in situ and conventional PCR to sections of adipose tissue samples of various anatomical origins from 19 individuals from Mexico and 20 from France who had died from causes other than TB. M. tuberculosis DNA could be detected by either or both techniques in fat tissue surrounding the kidneys, the stomach, the lymph nodes, the heart and the skin in 9/57 Mexican samples (6/19 individuals), and in 8/26 French samples (6/20 individuals). In addition, mycobacteria could be immuno-detected in perinodal adipose tissue of 1 out of 3 biopsy samples from individuals with active TB. In vitro, using a combination of adipose cell models, including the widely used murine adipose cell line 3T3-L1, as well as primary human adipocytes, we show that after binding to scavenger receptors, M. tuberculosis can enter within adipocytes, where it accumulates intracytoplasmic lipid inclusions and survives in a non-replicating state that is insensitive to the major anti-mycobacterial drug isoniazid.Conclusions/significanceGiven the abundance and the wide distribution of the adipose tissue throughout the body, our results suggest that this tissue, among others, might constitute a vast reservoir where the tubercle bacillus could persist for long periods of time, and avoid both killing by antimicrobials and recognition by the host immune system. In addition, M. tuberculosis-infected adipocytes might provide a new model to investigate dormancy and to evaluate new drugs for the treatment of persistent infection.
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- 2006
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5. Role of AmiA in the morphological transition of Helicobacter pylori and in immune escape.
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Catherine Chaput, Chantal Ecobichon, Nadège Cayet, Stephen E Girardin, Catherine Werts, Stéphanie Guadagnini, Marie-Christine Prévost, Dominique Mengin-Lecreulx, Agnès Labigne, and Ivo G Boneca
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Immunologic diseases. Allergy ,RC581-607 ,Biology (General) ,QH301-705.5 - Abstract
The human gastric pathogen Helicobacter pylori is responsible for peptic ulcers and neoplasia. Both in vitro and in the human stomach it can be found in two forms, the bacillary and coccoid forms. The molecular mechanisms of the morphological transition between these two forms and the role of coccoids remain largely unknown. The peptidoglycan (PG) layer is a major determinant of bacterial cell shape, and therefore we studied H. pylori PG structure during the morphological transition. The transition correlated with an accumulation of the N-acetyl-D-glucosaminyl-beta(1,4)-N-acetylmuramyl-L-Ala-D-Glu (GM-dipeptide) motif. We investigated the molecular mechanisms responsible for the GM-dipeptide motif accumulation, and studied the role of various putative PG hydrolases in this process. Interestingly, a mutant strain with a mutation in the amiA gene, encoding a putative PG hydrolase, was impaired in accumulating the GM-dipeptide motif and transforming into coccoids. We investigated the role of the morphological transition and the PG modification in the biology of H. pylori. PG modification and transformation of H. pylori was accompanied by an escape from detection by human Nod1 and the absence of NF-kappaB activation in epithelial cells. Accordingly, coccoids were unable to induce IL-8 secretion by AGS gastric epithelial cells. amiA is, to our knowledge, the first genetic determinant discovered to be required for this morphological transition into the coccoid forms, and therefore contributes to modulation of the host response and participates in the chronicity of H. pylori infection.
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- 2006
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6. Biosynthesis of cell wall mannan in the conidium and the mycelium ofAspergillusfumigatus
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Yanan Zhao, Anne Beauvais, David S. Perlin, Marie-Christine Prévost, Rémi Beau, Thierry Fontaine, Vishukumar Aimanianda, Jean-Paul Latgé, Christine Henry, Pauline Robinet, Arnaud Fekkar, Christoph Heddergott, and Isabelle Mouyna
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0301 basic medicine ,biology ,Immunology ,Fungal genetics ,Mannose ,Mannosyltransferases ,bacterial infections and mycoses ,biology.organism_classification ,Microbiology ,Yeast ,Aspergillus fumigatus ,carbohydrates (lipids) ,Cell wall ,03 medical and health sciences ,chemistry.chemical_compound ,030104 developmental biology ,chemistry ,Biochemistry ,Virology ,skin and connective tissue diseases ,Mycelium ,Mannan - Abstract
The galactomannan is a major cell wall molecule of Aspergillus fumigatus. This molecule is composed of a linear mannan with a repeating unit composed of four α1,6 and α1,2 linked mannose with side chains of galactofuran. To obtain a better understanding of the mannan biosynthesis in A. fumigatus, it was decided to undertake the successive deletion of the 11 genes which are putative orthologs of the mannosyltransferases responsible for establishing α1,6 and α1,2 mannose linkages in yeast. These deletions did not lead to a reduction of the mannan content of the cell wall of the mycelium of A. fumigatus. In contrast, the mannan content of the conidial cell wall was reduced and this reduction was associated with a partial disorganization of the cell wall leading to defects in conidial survival both in vitro and in vivo.
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- 2016
7. Anoxia and glucose supplementation preserve neutrophil viability and function
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Catherine Chaput, Cormac T. Taylor, Clarisse Chiche-Lapierre, Valérie Monceaux, Véronique Witko-Sarsat, Marie-Noëlle Ungeheuer, Benoit S. Marteyn, Philippe J. Sansonetti, and Marie-Christine Prévost
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0301 basic medicine ,Small interfering RNA ,medicine.medical_specialty ,Cell Survival ,Neutrophils ,Phagocytosis ,Guinea Pigs ,Immunology ,Apoptosis ,Cell Separation ,Transfection ,Biochemistry ,Andrology ,03 medical and health sciences ,0302 clinical medicine ,Anti-Infective Agents ,In vivo ,Proliferating Cell Nuclear Antigen ,Animals ,Humans ,Medicine ,Blood Transfusion ,Hypoxia ,Cell Shape ,bcl-2-Associated X Protein ,chemistry.chemical_classification ,Reactive oxygen species ,business.industry ,Cell Membrane ,Degranulation ,Chemotaxis ,Cell Biology ,Hematology ,In vitro ,Surgery ,Oxygen ,Glucose ,030104 developmental biology ,chemistry ,business ,Biomarkers ,030215 immunology - Abstract
Functional studies of human neutrophils and their transfusion for clinical purposes have been hampered by their short life span after isolation. Here, we demonstrate that neutrophil viability is maintained for 20 hours in culture media at 37°C under anoxic conditions with 3 mM glucose and 32 μg/mL dimethyloxalylglycine supplementation, as evidenced by stabilization of Mcl-1, proliferating cell nuclear antigen (PCNA), and pro-caspase-3. Notably, neutrophil morphology (nucleus shape and cell-surface markers) and functions (phagocytosis, degranulation, calcium release, chemotaxis, and reactive oxygen species production) were comparable to blood circulating neutrophils. The observed extension in neutrophil viability was reversed upon exposure to oxygen. Extending neutrophil life span allowed efficient transfection of plasmids (40% transfection efficiency) and short interfering RNA (interleukin-8, PCNA, and Bax), as a validation of effective and functional genetic manipulation of neutrophils both in vitro and in vivo. In vivo, transfusion of conditioned neutrophils in a neutropenic guinea pig model increased bacterial clearance of Shigella flexneri upon colonic infection, strongly suggesting that these conditioned neutrophils might be suitable for transfusion purposes. In summary, such conditioning of neutrophils in vitro should facilitate their study and offer new opportunities for genetic manipulation and therapeutic use.
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- 2016
8. Listeria monocytogenes switches from dissemination to persistence by adopting a vacuolar lifestyle in epithelial cells
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Christine Péchoux, Gabriel Mitchell, Eliane Milohanic, Marie-Christine Prévost, Pascale Cossart, Hélène Bierne, Mounia Kortebi, MICrobiologie de l'ALImentation au Service de la Santé (MICALIS), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, Lawrence Berkeley National Laboratory [Berkeley] (LBNL), Génétique Animale et Biologie Intégrative (GABI), AgroParisTech-Institut National de la Recherche Agronomique (INRA), Microscopie électronique (Plate-forme), Institut Pasteur [Paris], Interactions Bactéries-Cellules (UIBC), Institut National de la Recherche Agronomique (INRA)-Institut Pasteur [Paris]-Institut National de la Santé et de la Recherche Médicale (INSERM), The work of HB is supported by the French National Research Agency (ANR 11 BSV3 003 01, EPILIS), INRA (dept. MICA grant AO Blanc 2010), the French Ligue Nationale Contre le Cancer (comité régional d’Ile–de-France, LNCC 131/12) and the iXcore Foundation for Research. The work of MK is supported by a grant from the Lidex ALIAS of Université Paris- Saclay and by INRA (dept. MICA). GM is a postdoctoral scholar in the laboratory of Daniel A. Portnoy. Daniel A. Portnoy is supported by National Institutes of Health grants 1P01 AI063302 and 1R01 AI027655. GM is also supported by grants from the Fonds de Recherche du Québec - Santé (FRQS) and the Natural Sciences and Engineering Research Council of Canada (NSERC). PC acknowledges support from INFECT-ERA (PROANTILIS) and Labex IBEID., We are very grateful to Dan Portnoy for supporting this work and for helpful conversations. We thank L. Radoshevich for the critical reading of this manuscript, G. Lakisic for assistance, S. Aymerich for material support, E. Gouin for the generation of Listeria and ActA antibodies, T. Yoshimori for the gift of plasmid pEGFP-LC3, J. Swanson for the gift of pCBD-YFP, J.D. Sauer for the gift of mCherry-10403S, L. Travier, T. Couderc and M. Lecuit for the gift of EGDe-ΔactA+actA and ATG7 and BECN1 siRNAs, V. Libri for help in FACS procedures, and ImagGif and M. Metheule for help in TEM., ANR-11-BSV3-0003,EPILIS,Reprogrammation épigénétique par la bactérie pathogène Listeria monocytogenes(2011), ANR-13-IFEC-0004,PROANTILIS,Subversive pro- and anti-inflammation trade-offs promote infection by Listeria monocytogenes(2013), ANR-10-LABX-0062,IBEID,Integrative Biology of Emerging Infectious Diseases(2010), European Project: 321529,EC:FP7:HEALTH,FP7-ERANET-2012-RTD,INFECT-ERA(2013), Institut Pasteur [Paris] (IP), Institut National de la Recherche Agronomique (INRA)-Institut Pasteur [Paris] (IP)-Institut National de la Santé et de la Recherche Médicale (INSERM), Kortebi, Mounia, Milohanic, Eliane, Bierne, Hélène, vicente, marie-therese, BLANC - Reprogrammation épigénétique par la bactérie pathogène Listeria monocytogenes - - EPILIS2011 - ANR-11-BSV3-0003 - BLANC - VALID, ERA-NET Infect-ERA - Subversive pro- and anti-inflammation trade-offs promote infection by Listeria monocytogenes - - PROANTILIS2013 - ANR-13-IFEC-0004 - IFEC - VALID, Integrative Biology of Emerging Infectious Diseases - - IBEID2010 - ANR-10-LABX-0062 - LABX - VALID, Coordination of European funding for infectious diseases research - INFECT-ERA - - EC:FP7:HEALTH2013-01-01 - 2016-12-31 - 321529 - VALID, Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut Pasteur [Paris]-Institut National de la Recherche Agronomique (INRA), and ANR-10-LABX-62-IBEID,IBEID,Laboratoire d'Excellence 'Integrative Biology of Emerging Infectious Diseases'(2010)
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0301 basic medicine ,Cytoplasm ,Host cells ,Vacuole ,MESH: Heat-Shock Proteins ,medicine.disease_cause ,Pathology and Laboratory Medicine ,MESH: Listeria monocytogenes ,Hemolysin Proteins ,Cytosol ,Animal Cells ,Medicine and Health Sciences ,Listeriosis ,Pathogen ,lcsh:QH301-705.5 ,MESH: Bacterial Proteins ,Heat-Shock Proteins ,Staining ,biology ,Microbiology and Parasitology ,Cell staining ,Microbiologie et Parasitologie ,Bacterial Pathogens ,Liver ,MESH: Hemolysin Proteins ,Medical Microbiology ,MESH: Epithelial Cells ,MESH: Membrane Proteins ,Pathogens ,Cellular Structures and Organelles ,Cellular Types ,Anatomy ,Research Article ,lcsh:Immunologic diseases. Allergy ,Listeria ,Immunology ,Motility ,[SDV.BC]Life Sciences [q-bio]/Cellular Biology ,Research and Analysis Methods ,Microbiology ,MESH: Vacuoles ,Incubation period ,Cell Line ,03 medical and health sciences ,Listeria monocytogenes ,Bacterial Proteins ,Virology ,Genetics ,medicine ,Humans ,Molecular Biology ,[SDV.BC] Life Sciences [q-bio]/Cellular Biology ,Microbial Pathogens ,Intracellular pathogens ,MESH: Humans ,Bacteria ,Intracellular parasite ,MESH: Cytoplasm ,Organisms ,Biology and Life Sciences ,Membrane Proteins ,Epithelial Cells ,Cell Biology ,biology.organism_classification ,MESH: Cell Line ,030104 developmental biology ,lcsh:Biology (General) ,Specimen Preparation and Treatment ,MESH: Listeriosis ,Vacuoles ,Hepatocytes ,Parasitology ,lcsh:RC581-607 ,Viral Transmission and Infection - Abstract
Listeria monocytogenes causes listeriosis, a foodborne disease that poses serious risks to fetuses, newborns and immunocompromised adults. This intracellular bacterial pathogen proliferates in the host cytosol and exploits the host actin polymerization machinery to spread from cell-to-cell and disseminate in the host. Here, we report that during several days of infection in human hepatocytes or trophoblast cells, L. monocytogenes switches from this active motile lifestyle to a stage of persistence in vacuoles. Upon intercellular spread, bacteria gradually stopped producing the actin-nucleating protein ActA and became trapped in lysosome-like vacuoles termed Listeria-Containing Vacuoles (LisCVs). Subpopulations of bacteria resisted degradation in LisCVs and entered a slow/non-replicative state. During the subculture of host cells harboring LisCVs, bacteria showed a capacity to cycle between the vacuolar and the actin-based motility stages. When ActA was absent, such as in ΔactA mutants, vacuolar bacteria parasitized host cells in the so-called “viable but non-culturable” state (VBNC), preventing their detection by conventional colony counting methods. The exposure of infected cells to high doses of gentamicin did not trigger the formation of LisCVs, but selected for vacuolar and VBNC bacteria. Together, these results reveal the ability of L. monocytogenes to enter a persistent state in a subset of epithelial cells, which may favor the asymptomatic carriage of this pathogen, lengthen the incubation period of listeriosis, and promote bacterial survival during antibiotic therapy., Author summary L. monocytogenes is a model intracellular pathogen that replicates in the cytoplasm of mammalian cells and disseminate in the host using actin-based motility. Here, we reveal that L. monocytogenes changes its lifestyle and persists in lysosomal vacuoles during long-term infection of human hepatocytes and trophoblast cells. When the virulence factor ActA is not expressed, subpopulations of vacuolar bacteria enter a dormant viable but non-culturable (VBNC) state. This novel facet of the L. monocytogenes intracellular life could contribute to the asymptomatic carriage of this pathogen in epithelial tissues and render it tolerant to antibiotic therapy and undetectable by routine culture techniques.
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- 2017
9. Apical Invasion of Intestinal Epithelial Cells by Salmonella typhimurium Requires Villin to Remodel the Brush Border Actin Cytoskeleton
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Nouara Lhocine, Perrine Bomme, Sylvie Robine, Philippe J. Sansonetti, Ellen T. Arena, Marie-Christine Prévost, Florent Ubelmann, Centro de Estudos de Doenças Crónicas (CEDOC), and NOVA Medical School|Faculdade de Ciências Médicas (NMS|FCM)
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Salmonella typhimurium ,Cancer Research ,Brush border ,macromolecular substances ,Microbiology ,digestive system ,Ruffle assembly ,Article ,Cell Line ,03 medical and health sciences ,Intestinal mucosa ,Bacterial Proteins ,Immunology and Microbiology(all) ,Virology ,Humans ,Intestinal Mucosa ,Molecular Biology ,Actin ,030304 developmental biology ,0303 health sciences ,biology ,Microvilli ,030306 microbiology ,Effector ,Microfilament Proteins ,Epithelial Cells ,Actin cytoskeleton ,Endocytosis ,3. Good health ,Cell biology ,Actin Cytoskeleton ,Host-Pathogen Interactions ,biology.protein ,Phosphorylation ,Parasitology ,Protein Tyrosine Phosphatases ,Villin - Abstract
Summary Salmonella invasion of intestinal epithelial cells requires extensive, though transient, actin modifications at the site of bacterial entry. The actin-modifying protein villin is present in the brush border where it participates in the constitution of microvilli and in epithelial restitution after damage through its actin-severing activity. We investigated a possible role for villin in Salmonella invasion. The absence of villin, which is normally located at the bacterial entry site, leads to a decrease in Salmonella invasion. Villin is necessary for early membrane-associated processes and for optimal ruffle assembly by balancing the steady-state level of actin. The severing activity of villin is important for Salmonella invasion in vivo. The bacterial phosphatase SptP tightly regulates villin phosphorylation, while the actin-binding effector SipA protects F-actin and counterbalances villin-severing activity. Thus, villin plays an important role in establishing the balance between actin polymerization and actin severing to facilitate the initial steps of Salmonella entry., Graphical Abstract, Highlights • The host actin-binding protein villin is required for Salmonella apical invasion • Villin plays a role in Salmonella ruffle formation and actin dynamics • Villin-severing activity promotes Salmonella invasion in cells and in vivo • The bacterial effectors SipA and SptP regulate villin activities, Salmonella interacts directly with the brush border of intestinal epithelial cells to promote its internalization. Lhocine et al. demonstrate that the rapid cytoskeleton remodeling at the bacterial entry site requires villin, an apical actin-binding protein. Villin is the target of bacterial effectors, SipA and SptP, which regulate its actin-modifying properties.
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- 2015
10. Aspergillus fumigatusdevoid of cell wall β-1,3-glucan is viable, massively sheds galactomannan and is killed by septum formation inhibitors
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Vishukumar Aimanianda, Zhaojun Zhu, Jean-Paul Latgé, Johannes Wagener, Karl Dichtl, Marie-Christine Prévost, Sweta Samantaray, and Frank Ebel
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Aspergillus ,biology ,Echinocandin ,Galactosaminogalactan ,Wild type ,bacterial infections and mycoses ,biology.organism_classification ,Microbiology ,3. Good health ,Aspergillus fumigatus ,chemistry.chemical_compound ,Galactomannan ,chemistry ,medicine ,Caspofungin ,Molecular Biology ,Echinocandins ,medicine.drug - Abstract
Echinocandins inhibit β-1,3-glucan synthesis and are one of the few antimycotic drug classes effective against Aspergillus spp. In this study, we characterized the β-1,3-glucan synthase Fks1 of Aspergillus fumigatus, the putative target of echinocandins. Data obtained with a conditional mutant suggest that fks1 is not essential. In agreement, we successfully constructed a viable Δfks1 deletion mutant. Lack of Fks1 results in characteristic growth phenotypes similar to wild type treated with echinocandins and an increased susceptibility to calcofluor white and sodium dodecyl sulfate. In agreement with Fks1 being the only β-1,3-glucan synthase in A. fumigatus, the cell wall is devoid of β-1,3-glucan. This is accompanied by a compensatory increase of chitin and galactosaminogalactan and a significant decrease in cell wall galactomannan due to a massively enhanced galactomannan shedding. Our data furthermore suggest that inhibition of hyphal septation can overcome the limitations of echinocandin therapy. Compounds inhibiting septum formation boosted the antifungal activity of caspofungin. Thus, development of clinically applicable inhibitors of septum formation is a promising strategy to improve existing antifungal therapy.
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- 2014
11. Deciphering the role of the chitin synthase families 1 and 2 in thein vivoandin vitrogrowth ofAspergillus fumigatusby multiple gene targeting deletion
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Edyta Szewczyk, Laetitia Muszkieta, Marie-Christine Prévost, Emilia Mellado, Simonetta Gribaldo, Vishukumar Aimanianda, Jean-Paul Latgé, and Laura Alcazar-Fuoli
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2. Zero hunger ,0303 health sciences ,biology ,030306 microbiology ,Immunology ,Mutant ,Virulence ,Conidiation ,Chitin synthase ,biology.organism_classification ,Microbiology ,Aspergillus fumigatus ,Cell wall ,03 medical and health sciences ,chemistry.chemical_compound ,Chitin ,chemistry ,Virology ,biology.protein ,Gene ,030304 developmental biology - Abstract
Summary Although chitin is an essential component of the fungal cell wall (CW), its biosynthesis and role in virulence is poorly understood. In Aspergillus fumigatus, there are eight chitin synthase (CHS) genes belonging to two families CHSA-C, CHSG in family 1 and CHSF, CHSD, CSMA, CSMB in family 2). To understand the function of these CHS genes, their single and multiple deletions were performed using β-rec/six system to be able to delete all genes within each family (up to a quadruple ΔchsA/C/B/G mutant in family 1 and a quadruple ΔcsmA/csmB/F/D mutant in family 2). Radial growth, conidiation, mycelial/conidial morphology, CW polysaccharide content, Chs-activity, susceptibility to antifungal molecules and pathogenicity in experimental animal aspergillosis were analysed for all the mutants. Among the family 1 CHS, ΔchsA, ΔchsB and ΔchsC mutants showed limited impact on chitin synthesis. In contrast, there was reduced conidiation, altered mycelial morphotype and reduced growth and Chs-activity in the ΔchsG and ΔchsA/C/B/G mutants. In spite of this altered phenotype, these two mutants were as virulent as the parental strain in the experimental aspergillosis models. Among family 2 CHS, phenotypic defects mainly resulted from the CSMA deletion. Despite significant morphological mycelial and conidial growth phenotypes in the quadruple ΔcsmA/csmB/F/D mutant, the chitin content was poorly affected by gene deletions in this family. However, the entire mycelial cell wall structure was disorganized in the family 2 mutants that may be related to the reduced pathogenicity of the quadruple ΔcsmA/csmB/F/D mutant strain compared to the parental strain, in vivo. Deletion of the genes encompassing the two families (ΔcsmA/csmB/F/G) showed that in spite of being originated from an ancient divergence of fungi, these two families work cooperatively to synthesize chitin in A. fumigatus and demonstrate the essentiality of chitin biosynthesis for vegetative growth, resistance to antifungal drugs, and virulence of this filamentous fungus.
- Published
- 2014
12. A large collection of novel nematode-infecting microsporidia and their diverse interactions with C. elegans and other related nematodes
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Emily R. Troemel, Gaotian Zhang, Martin Sachse, Marie-Christine Prévost, Robert J. Luallen, and Marie-Anne Félix
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food.ingredient ,biology ,Host (biology) ,Intracellular parasite ,fungi ,biology.organism_classification ,Microsporidiosis ,medicine.disease ,Microbiology ,Caenorhabditis ,Nematode ,food ,parasitic diseases ,Microsporidia ,medicine ,Nematocida ,Nematocida parisii - Abstract
Microsporidia are fungi-related intracellular pathogens that may infect virtually all animals, but are poorly understood. The nematode Caenorhabditis elegans has recently become a model host for studying microsporidia through the identification of its natural microsporidian pathogen Nematocida parisii. However, it was unclear how widespread and diverse microsporidia infections are in C. elegans or other related nematodes in the wild. Here we describe the isolation and culture of 47 nematodes with microsporidian infections. N. parisii is found to be the most common microsporidia infecting C. elegans in the wild. In addition, we further describe and name six new species in the Nematocida genus. Our sampling and phylogenetic analysis further identify two subclades that are genetically distinct from Nematocida, and we name them Enteropsectra and Pancytospora. Interestingly, unlike Nematocida, these two genera belong to the main clade of microsporidia that includes human pathogens. All of these microsporidia are horizontally transmitted and most specifically infect intestinal cells, except Pancytospora epiphaga that replicates mostly in the epidermis of its Caenorhabditis host. At the subcellular level in the infected host cell, spores of the novel genus Enteropsectra show a characteristic apical distribution and exit via budding off of the plasma membrane, instead of exiting via exocytosis as spores of Nematocida. Host specificity is broad for some microsporidia, narrow for others: indeed, some microsporidia can infect Oscheius tipulae but not its sister species, and conversely. We also show that N. ausubeli fails to strongly induce in C. elegans the transcription of genes that are induced by other Nematocida species, suggesting it has evolved mechanisms to prevent induction of this host response. Altogether, these newly isolated species illustrate the diversity and ubiquity of microsporidian infections in nematodes, and provide a rich resource to investigate host-parasite coevolution in tractable nematode hosts.Author SummaryMicrosporidia are microbial parasites that live inside their host cells and can cause disease in humans and many other animals. The small nematode worm Caenorhabditis elegans has recently become a convenient model host for studying microsporidian infections. In this work, we sample Caenorhabditis and other small nematodes and 47 associated microsporidian strains from the wild. We characterize the parasites for their position in the evolutionary tree of microsporidia and for their lifecycle and morphology. We find several new species and genera, especially some that are distantly related to the previously known Nematocida parisii and instead closely related to human pathogens. We find that some of these species have a narrow host range. We studied two species in detail using electron microscopy and uncover a new likely mode of exit from the host cell, by budding off the host cell plasma membrane rather than by fusion of a vesicle to the plasma membrane as in N. parisii. We also find a new species that infects the epidermis and muscles of Caenorhabditis rather than the host intestinal cells and is closely related to human pathogens. Finally, we find that one Nematocida species fails to elicit the same host response that other Nematocida species do. These new microsporidia open up many windows into microsporidia biology and opportunities to investigate host-parasite coevolution in the C. elegans system.
- Published
- 2016
13. Author response: Sequestration of host metabolism by an intracellular pathogen
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Agathe Subtil, Steven G. Ball, Mathieu Ducatez, Amanda M. Giebel, Marie-Christine Prévost, David E. Nelson, Stéphanie Perrinet, Olivier Gorgette, and Lena Gehre
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0301 basic medicine ,Intracellular pathogen ,03 medical and health sciences ,030104 developmental biology ,Host (biology) ,Metabolism ,Biology ,Microbiology - Published
- 2016
14. Sequestration of host metabolism by an intracellular pathogen
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Lena Gehre, Agathe Subtil, Mathieu Ducatez, David E. Nelson, Steven G. Ball, Marie-Christine Prévost, Stéphanie Perrinet, Olivier Gorgette, Amanda M. Giebel, Biologie cellulaire de l'Infection microbienne - Cellular Biology of Microbial Infection, Institut Pasteur [Paris]-Centre National de la Recherche Scientifique (CNRS), Microscopie électronique (Plate-forme), Institut Pasteur [Paris], Unité de Glycobiologie Structurale et Fonctionnelle UMR 8576 (UGSF), Université de Lille-Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS), Indiana University [Bloomington], Indiana University System, Indiana University School of Medicine, This work was supported by an ERC Starting Grant (NUChLEAR N°282046), the ANR (Ménage à trois, ANR-12-BSV2-0009 and Expendo ANR-14-CE-0024), the Institut Pasteur and the Centre National de la Recherche Scientifique., We thank Dr. A Dautry for critical reading of the manuscript. We are thankful to people who contributed tools and reagents: I Clarke (University of Southampton, UK), N Mizushima (Tokyo Medical and Dental University, Japan), Nobuhiro Ishida (Chiba Institute of Science, Japan), and R Valdivia (Duke University Medical Center, USA)., ANR-12-BSV2-0009,Ménage à trois,Une symbiose tripartite explique l'origine du plaste et son intégration métabolique(2012), ANR-14-CE11-0024,Expendo,Vers l'endosymbiose expérimentale(2014), European Project: 282046,EC:FP7:ERC,ERC-2011-StG_20101109,NUCHLEAR(2012), Biologie cellulaire de l'Infection microbienne, Unité de Glycobiologie Structurale et Fonctionnelle - UMR 8576 (UGSF), Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), CNRS, Université de Lille, Microscopie ultrastructurale (plate-forme), Microscopie Ultrastructurale (Plate-forme), Unité de Glycobiologie Structurale et Fonctionnelle - UMR 8576 [UGSF], Department of Biology [Bloomington], Unité de Glycobiologie Structurale et Fonctionnelle UMR 8576 [UGSF], Biologie cellulaire de l'infection microbienne, Institut Pasteur [Paris] (IP)-Centre National de la Recherche Scientifique (CNRS), Institut Pasteur [Paris] (IP), and Université de Lille-Centre National de la Recherche Scientifique (CNRS)
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0301 basic medicine ,chlamydia trachomatis ,Human pathogen ,Vacuole ,[SDV.MHEP.PSR]Life Sciences [q-bio]/Human health and pathology/Pulmonology and respiratory tract ,Type three secretion system ,chemistry.chemical_compound ,[SDV.MHEP.MI]Life Sciences [q-bio]/Human health and pathology/Infectious diseases ,[SDV.BC.IC]Life Sciences [q-bio]/Cellular Biology/Cell Behavior [q-bio.CB] ,Biology (General) ,Microbiology and Infectious Disease ,Glycogen ,General Neuroscience ,General Medicine ,Glycogen Synthase ,Biochemistry ,Host-Pathogen Interactions ,Nucleotide Transport Proteins ,Medicine ,Research Article ,Human ,Uridine Diphosphate Glucose ,QH301-705.5 ,Science ,infectious disease ,030106 microbiology ,Biology ,glycogen metabolism ,General Biochemistry, Genetics and Molecular Biology ,Cell Line ,03 medical and health sciences ,intracellular parasites ,Bacterial Proteins ,Animals ,Humans ,Glycogen synthase ,General Immunology and Microbiology ,Intracellular parasite ,cell biology ,host-pathogens interactions ,human ,infectious desease ,microbiology ,Biological Transport ,Cell Biology ,biology.organism_classification ,[SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology ,Cytosol ,chemistry ,[SDV.GEN.GH]Life Sciences [q-bio]/Genetics/Human genetics ,Vacuoles ,biology.protein ,Other ,Bacteria - Abstract
For intracellular pathogens, residence in a vacuole provides a shelter against cytosolic host defense to the cost of limited access to nutrients. The human pathogen Chlamydia trachomatis grows in a glycogen-rich vacuole. How this large polymer accumulates there is unknown. We reveal that host glycogen stores shift to the vacuole through two pathways: bulk uptake from the cytoplasmic pool, and de novo synthesis. We provide evidence that bacterial glycogen metabolism enzymes are secreted into the vacuole lumen through type 3 secretion. Our data bring strong support to the following scenario: bacteria co-opt the host transporter SLC35D2 to import UDP-glucose into the vacuole, where it serves as substrate for de novo glycogen synthesis, through a remarkable adaptation of the bacterial glycogen synthase. Based on these findings we propose that parasitophorous vacuoles not only offer protection but also provide a microorganism-controlled metabolically active compartment essential for redirecting host resources to the pathogens. DOI: http://dx.doi.org/10.7554/eLife.12552.001, eLife digest Chlamydia trachomatis is the most common sexually transmitted bacteria that causes disease. Infections often do not produce any obvious symptoms, but can lead to infertility or other severe problems if left untreated. This microbe is also the leading cause of blindness by an infectious agent.The bacteria grow in the human body by infecting host cells. Inside these cells, the bacteria are found inside compartments known as inclusions, which protect them from the host’s defense responses and enable them to create a comfortable environment for themselves. However, this comes at a cost because the bacteria lose immediate access to the nutrients in the rest of the host cell. Thus, C.trachomatis has developed ways to import these nutrients into inclusions, and, more generally, to take the control of its interactions with the host cell. The inclusions built up by C. trachomatis contain a high amount of glycogen, a carbohydrate that generally acts as an energy storage molecule. Although this observation was made many decades ago, the molecular mechanism by which such a large molecule accumulates in the inclusion has not been clarified. Gehre et al. have now used a variety of cell biology techniques to address this question. The experiments show that there are two different pathways through which glycogen accumulates within the inclusion. Some glycogen is transported in bulk from the interior of the host cell into the inclusion. However, the bacteria also make new glycogen in the inclusion from a building block molecule called UDP-glucose. To do this, the bacteria recruit a host transport molecule to the membrane that surrounds the inclusion. This transport molecule brings UDP-glucose into the inclusion, where an enzyme called glycogen synthase – which is released by the bacteria – uses the UDP-glucose to make glycogen. The C. trachomatis glycogen synthase is unusual because most other bacteria can only make glycogen from another type of glucose. By using both pathways, C. trachomatis is able to trap most of the glycogen stores of the infected cell within the inclusion so that they are inaccessible to the host but ready for the bacteria to use. Previous work has shown that C. trachomatis is much better at accumulating glycogen than other Chlamydia bacteria are. Therefore, a future challenge will be to find out exactly how this helps C. trachomatis survive inside human cells. DOI: http://dx.doi.org/10.7554/eLife.12552.002
- Published
- 2016
15. Transcytosis of HTLV-1 across a tight human epithelial barrier and infection of subepithelial dendritic cells
- Author
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Florence Guivel-Benhassine, Nina-Francesca Gnädig, Antoine Gessain, Simona Ozden, Olivier Schwartz, Patricia Jeannin, Sandra Martin-Latil, Pierre-Emmanuel Ceccaldi, Marion Desdouits, Adeline Mallet, Marie-Christine Prévost, Epidémiologie et Physiopathologie des Virus Oncogènes, Institut Pasteur [Paris]-Centre National de la Recherche Scientifique (CNRS), Microscopie Ultrastructurale (Plate-forme), Virus et Immunité, Centre National de la Recherche Scientifique (CNRS)-Institut Pasteur [Paris], Cellule Pasteur, Université Paris Diderot - Paris 7 (UPD7)-PRES Sorbonne Paris Cité, This work and S.M.-L. were supported by French Agence Nationnale de la Recherche. M.D. is recipient of a fellowship from the French Ministry of Education and Research. Part of the microscopy was performed at the Dynamic Imaging Platform, Imagopole, Pasteur Institute, and Institut Pasteur [Paris] (IP)-Centre National de la Recherche Scientifique (CNRS)
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Sexual transmission ,T-Lymphocytes ,[SDV]Life Sciences [q-bio] ,viruses ,Immunology ,Cell ,Biology ,Biochemistry ,Tight Junctions ,03 medical and health sciences ,0302 clinical medicine ,Microscopy, Electron, Transmission ,immune system diseases ,hemic and lymphatic diseases ,Tropical spastic paraparesis ,medicine ,Humans ,030304 developmental biology ,Human T-lymphotropic virus 1 ,0303 health sciences ,Transmission (medicine) ,Virion ,virus diseases ,Epithelial Cells ,Dendritic Cells ,Cell Biology ,Hematology ,medicine.disease ,HTLV-I Infections ,Virology ,Coculture Techniques ,Epithelium ,3. Good health ,Lymphoma ,Leukemia ,Enterocytes ,HEK293 Cells ,medicine.anatomical_structure ,Transcytosis ,030220 oncology & carcinogenesis ,Caco-2 Cells ,HT29 Cells - Abstract
Human T-cell leukemia virus type 1 (HTLV-1) is the causative agent of adult T-cell leukemia/lymphoma and HTLV-1–associated myelopathy/tropical spastic paraparesis. In addition to blood transfusion and sexual transmission, HTLV-1 is transmitted mainly through prolonged breastfeeding, and such infection represents a major risk for the development of adult T-cell leukemia/lymphoma. Although HTLV-1–infected lymphocytes can be retrieved from maternal milk, the mechanisms of HTLV-1 transmission through the digestive tract remain unknown. In the present study, we assessed HTLV-1 transport across the epithelial barrier using an in vitro model. Our results show that the integrity of the epithelial barrier was maintained during coculture with HTLV-1–infected lymphocytes, because neither morphological nor functional alterations of the cell monolayer were observed. Enterocytes were not susceptible to HTLV-1 infection, but free infectious HTLV-1 virions could cross the epithelial barrier via a transcytosis mechanism. Such virions were able to infect productively human dendritic cells located beneath the epithelial barrier. Our data indicate that HTLV-1 crosses the tight epithelial barrier without disruption or infection of the epithelium to further infect target cells such as dendritic cells. The present study provides the first data pertaining to the mode of HTLV-1 transport across a tight epithelial barrier, as can occur during mother-to-child HTLV-1 transmission during breastfeeding.
- Published
- 2012
16. Characterization of the elongasome core PBP2 : MreC complex of Helicobacter pylori
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Sylviane Hoos, Christine Ebel, Alexandre Martins, Christine Schmitt, Frank Gabel, Chantal Ecobichon, Patrick England, Andréa Dessen, Pierre-Jean Matteï, Ivo G. Boneca, Meriem El Ghachi, Marie-Christine Prévost, and Frédéric Colland
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chemistry.chemical_classification ,0303 health sciences ,030306 microbiology ,Cell ,Periplasmic space ,biochemical phenomena, metabolism, and nutrition ,Biology ,Cell morphology ,Microbiology ,Yeast ,Bacterial cell structure ,Amino acid ,law.invention ,03 medical and health sciences ,medicine.anatomical_structure ,chemistry ,Biochemistry ,law ,polycyclic compounds ,Recombinant DNA ,Biophysics ,medicine ,Surface plasmon resonance ,Molecular Biology ,030304 developmental biology - Abstract
Summary The definition of bacterial cell shape is a complex process requiring the participation of multiple components of an intricate macromolecular machinery. We aimed at characterizing the determinants involved in cell shape of the helical bacterium Helicobacter pylori. Using a yeast two-hybrid screen with the key cell elongation protein PBP2 as bait, we identified an interaction between PBP2 and MreC. The minimal region of MreC required for this interaction ranges from amino acids 116 to 226. Using recombinant proteins, we showed by affinity and size exclusion chromatographies and surface plasmon resonance that PBP2 and MreC form a stable complex. In vivo, the two proteins display a similar spatial localization and their complex has an apparent 1:1 stoichiometry; these results were confirmed in vitro by analytical ultracentrifugation and chemical cross-linking. Small angle X-ray scattering analyses of the PBP2 : MreC complex suggest that MreC interacts directly with the C-terminal region of PBP2. Depletion of either PBP2 or MreC leads to transition into spherical cells that lose viability. Finally, the specific expression in trans of the minimal interacting domain of MreC with PBP2 in the periplasmic space leads to cell rounding, suggesting that the PBP2/MreC complex formation in vivo is essential for cell morphology.
- Published
- 2011
17. Simple and elegant design of a virion egress structure in Archaea
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Patrick Forterre, Sonja-Verena Albers, Soizick Lucas, Julia Reimann, David Prangishvili, Marie-Christine Prévost, Gérard Pehau-Arnaudet, Tessa E. F. Quax, Biologie Moléculaire du Gène chez les Extrêmophiles (BMGE), Institut Pasteur [Paris], Institut de génétique et microbiologie [Orsay] (IGM), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), and Institut Pasteur [Paris] (IP)
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Sulfolobus acidocaldarius ,Hot Temperature ,Viral protein ,Immunoelectron microscopy ,Population ,Rudiviridae ,Biology ,medicine.disease_cause ,03 medical and health sciences ,medicine ,[SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology ,education ,Virus Release ,030304 developmental biology ,Host cell surface ,0303 health sciences ,education.field_of_study ,Multidisciplinary ,030306 microbiology ,Virus Assembly ,Virion ,Biological Sciences ,Hydrogen-Ion Concentration ,bacterial infections and mycoses ,Archaea ,Virology ,respiratory tract diseases ,[SDV.MP]Life Sciences [q-bio]/Microbiology and Parasitology ,Biophysics ,Heterologous expression - Abstract
Some viruses of Archaea use an unusual egress mechanism that involves the formation of virus-associated pyramids (VAPs) on the host cell surface. At the end of the infection cycle, these structures open outward and create apertures through which mature virions escape from the cell. Here we describe in detail the structure and composition of VAPs formed by the Sulfolobus islandicus rod-shaped virus 2 (SIRV2) in cells of its hyperthermophilic archaeal host. We show that the VAPs are stable and autonomous assemblies that can be isolated from membranes of infected cells and purified without affecting their structure. The purified VAPs are heterogeneous in size, reflecting the dynamics of VAP development in a population of infected cells; however, they have a uniform geometry, consisting of seven isosceles triangular faces forming a baseless pyramid. Biochemical and immunoelectron microscopy analyses revealed that the 10-kDa P98 protein encoded by the SIRV2 virus is the sole component of the VAPs. The VAPs were produced in Sulfolobus acidocaldarius and Escherichia coli by heterologous expression of the SIRV2-P98 gene. The results confirm that P98 is the only constituent of the VAPs and demonstrate that no other viral protein is involved in the assembly of pyramids. P98 was able to produce stable structures under conditions ranging from moderate to extremely high temperatures (80 °C) and from neutral to extremely acidic pH (pH 2), demonstrating another remarkable property of this exceptional viral protein.
- Published
- 2011
18. A M23B family metallopeptidase of Helicobacter pylori required for cell shape, pole formation and virulence
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Mathilde Bonis, Chantal Ecobichon, Marie-Christine Prévost, Ivo G. Boneca, and Stéphanie Guadagnini
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0303 health sciences ,biology ,030306 microbiology ,Virulence ,Motility ,Helicobacter pylori ,biology.organism_classification ,Microbiology ,Phenotype ,In vitro ,03 medical and health sciences ,Transformation (genetics) ,Molecular Biology ,Gene ,Bacteria ,030304 developmental biology - Abstract
Summary The molecular basis of the regulation of specific shapes and their role for the bacterial fitness remain largely unknown. We focused in this study on the Gram-negative and spiral-shaped Helicobacter pylori. To colonize its unique niche, H. pylori needs to reach quickly the human gastric mucosa, by swimming to and through the mucus layer. For that reason, the specific shape of H. pylori is predicted to be necessary for optimal motility in vivo, and consequently for its colonization ability. Here, we describe the involvement of a PG-modifying enzyme, HdpA (HP0506), in the mouse colonization ability of this bacterium, by regulating its shape. Indeed, the inactivation of the hp0506 gene led to a stocky and branched phenotype, affecting H. pylori colonization capacity despite a normal motility phenotype in vitro. In contrast, the overexpression of the hp0506 gene induced the transformation of H. pylori from rod to dividing cocci shaped bacteria. Furthermore, we demonstrated by PG analysis and enzymology, that HdpA carried both d,d-carboxypeptidase and d,d-endopeptidase activities. Thus, HdpA is the first enzyme belonging to the M23-peptidase family able to perform the d,d-carboxypeptidation and regulate cell shape.
- Published
- 2010
19. Members of protein O-mannosyltransferase family in Aspergillus fumigatus differentially affect growth, morphogenesis and viability
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Olaf Kniemeyer, Dirk Wartenberg, Jagadeesh Bayry, Emilia Mellado, Anne Beauvais, Céline Loussert, Isabelle Mouyna, Jean-Paul Latgé, Thomas Jank, Sabine Strahl, Michel Huerre, Marie-Christine Prévost, Vishukumar Aimanianda, J. Sarfati, and Axel A. Brakhage
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Genetics ,0303 health sciences ,Subfamily ,biology ,030306 microbiology ,Mutant ,Morphogenesis ,Conidiation ,biology.organism_classification ,Microbiology ,Phenotype ,Transmembrane protein ,Aspergillus fumigatus ,03 medical and health sciences ,Molecular Biology ,Gene ,030304 developmental biology - Abstract
Summary O-mannosylation is an essential protein modification in eukaryotes. It is initiated at the endoplasmic reticulum by O-mannosyltransferases (PMT) that are evolutionary conserved from yeast to humans. The PMT family is phylogenetically classified into PMT1, PMT2 and PMT4 subfamilies, which differ in protein substrate specificity and number of genes per subfamily. In this study, we characterized for the first time the whole PMT family of a pathogenic filamentous fungus, Aspergillus fumigatus. Genome analysis showed that only one member of each subfamily is present in A. fumigatus, PMT1, PMT2 and PMT4. Despite the fact that all PMTs are transmembrane proteins with conserved peptide motifs, the phenotype of each PMT deletion mutant was very different in A. fumigatus. If disruption of PMT1 did not reveal any phenotype, deletion of PMT2 was lethal. Disruption of PMT4 resulted in abnormal mycelial growth and highly reduced conidiation associated to significant proteomic changes. The double pmt1pmt4 mutant was lethal. The single pmt4 mutant exhibited an exquisite sensitivity to echinocandins that is associated to major changes in the expression of signal transduction cascade genes. These results indicate that the PMT family members play a major role in growth, morphogenesis and viability of A. fumigatus.
- Published
- 2010
20. Escherichia coli K-12 possesses multiple cryptic but functional chaperone-usher fimbriae with distinct surface specificities
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Charalampia-Georgia Korea, Jean-Marc Ghigo, Marie-Christine Prévost, Réana Badouraly, and Christophe Beloin
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Genetics ,0303 health sciences ,030306 microbiology ,Operon ,Fimbria ,Catabolite repression ,Biology ,biology.organism_classification ,medicine.disease_cause ,Microbiology ,Chaperone-Usher fimbriae ,Bacterial adhesin ,03 medical and health sciences ,Pathogenic Escherichia coli ,medicine ,Gene ,Escherichia coli ,Ecology, Evolution, Behavior and Systematics ,030304 developmental biology - Abstract
Commensal and pathogenic Escherichia coli adherence to host and environmental surfaces is mediated by a variety of adhesins. Although extensively studied as a model bacterium, 34% of the genes in the E. coli K-12 genome have no known function. We hypothesized that some of them may correspond to functional adhesins. We characterized E. coli K-12 ycb, ybg, yfc, yad, yra, sfm and yeh operons, which display sequence and organizational homologies to type 1 fimbriae exported by the chaperone/usher pathway. We showed that, although these operons are poorly expressed under laboratory conditions, six of them are nevertheless functional when expressed, and promote adhesion to abiotic and/or epithelial cell surfaces. While the studied fimbriae display different binding specificities, we obtained evidence of synergy/interference with other adhesins such as Ag43 or type 1 fimbriae. We showed that their expression is under the negative control of H-NS and, except for yad, subjected to cAMP receptor protein-mediated activation and carbon catabolite repression. These results therefore demonstrate that ycb, yfc, yad, yra, sfm and yeh operons encode cryptic but functional fimbriae adhesins whose expression following environmental modifications could contribute to E. coli's ability to adhere to and colonize a wide diversity of surfaces in its various ecological niches.
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- 2010
21. Biofilm formation by saprophytic and pathogenic leptospires
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Paula Ristow, Sophie Kernéis, Marie-Christine Prévost, Christine Schmitt, Mathieu Picardeau, Walter Lilenbaum, and Pascale Bourhy
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Leptospira ,Microscopy ,biology ,Host (biology) ,Biofilm ,biology.organism_classification ,medicine.disease ,Microbiology ,Leptospirosis ,Microbial ecology ,Biofilms ,Leptospiraceae ,Environmental Microbiology ,Microscopy, Electron, Scanning ,medicine ,Animals ,Humans ,Polystyrenes ,Spirochaete ,Glass ,Bacteria - Abstract
Leptospires exist as saprophytic organisms that are aquatic or as pathogens that are able to survive in water. Leptospirosis is transmitted to humans through environmental surface waters contaminated by the urine of mammals, usually rodents, which are chronically infected by pathogenic strains. The ecology of Leptospira spp. prompted us to evaluate if these spirochaetes were able to form biofilms. This study investigated the characteristics of biofilm development by both saprophytic and pathogenic Leptospira species using microscopic examinations and a polystyrene plate model. Biofilms were formed preferentially on glass and polystyrene surfaces. Electron microscopic images showed cells embedded in an extracellular matrix. The formation of such a biofilm is consistent with the life of saprophytic strains in water and may help pathogenic strains to survive in environmental habitats and to colonize the host.
- Published
- 2008
22. Human Blood-Brain Barrier Disruption by Retroviral-Infected Lymphocytes: Role of Myosin Light Chain Kinase in Endothelial Tight-Junction Disorganization
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Marie-Christine Prévost, Christine Schmitt, Simona Ozden, Antoine Gessain, Babette B. Weksler, Pierre-Emmanuel Ceccaldi, Philippe V. Afonso, Pierre-Olivier Couraud, Ignacio A. Romero, Danielle Seilhean, Epidémiologie et Physiopathologie des Virus Oncogènes, Institut Pasteur [Paris]-Centre National de la Recherche Scientifique (CNRS), Microscopie électronique (Plate-forme), Institut Pasteur [Paris], CHU Pitié-Salpêtrière [APHP], Weill Medical College of Cornell University [New York], Institut Cochin (UMR_S567 / UMR 8104), Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Descartes - Paris 5 (UPD5), Department of Biological Sciences, The Open University [Milton Keynes] (OU), Institut Pasteur [Paris] (IP)-Centre National de la Recherche Scientifique (CNRS), Institut Pasteur [Paris] (IP), CHU Pitié-Salpêtrière [AP-HP], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU), Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Sorbonne Université (SU)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP), Institut Pasteur [Paris] - Centre National de la Recherche Scientifique (CNRS), Laboratoire de Neuropathologie, Hôpital de la Salpétrière, and Université Paris Descartes - Paris 5 (UPD5) - Institut National de la Santé et de la Recherche Médicale (INSERM) - Centre National de la Recherche Scientifique (CNRS)
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Pathology ,MESH : Cerebellum ,[SDV]Life Sciences [q-bio] ,MESH : Lymphocytes ,MESH : Herpesviridae Infections ,MESH : Models, Immunological ,MESH : Herpesvirus 8, Human ,MESH : Blood-Brain Barrier ,0302 clinical medicine ,Cerebellum ,Interleukin-1alpha ,Tropical spastic paraparesis ,Immunology and Allergy ,Lymphocytes ,Transcellular ,Cell Line, Transformed ,MESH : Tumor Necrosis Factor-alpha ,Human T-lymphotropic virus 1 ,0303 health sciences ,MESH : Neoplasm Recurrence, Local ,Tight junction ,MESH : Neurodegenerative Diseases ,MESH : Cell Line, Transformed ,Neurodegenerative Diseases ,MESH : Human T-lymphotropic virus 1 ,Paraparesis, Tropical Spastic ,3. Good health ,Cell biology ,MESH : Pleural Effusion, Malignant ,medicine.anatomical_structure ,Spinal Cord ,Blood-Brain Barrier ,Paracellular transport ,Infiltration (medical) ,medicine.medical_specialty ,Myosin light-chain kinase ,Endothelium ,Immunology ,MESH : Lymphoma, AIDS-Related ,Biology ,MESH : Myosin-Light-Chain Kinase ,MESH : Lymphoma ,Myosin light chain kinase activity ,Tight Junctions ,03 medical and health sciences ,medicine ,Humans ,MESH : Interleukin-1alpha ,Myosin-Light-Chain Kinase ,030304 developmental biology ,MESH : Tight Junctions ,Tumor Necrosis Factor-alpha ,MESH : Endothelial Cells ,MESH : Humans ,Models, Immunological ,Endothelial Cells ,Membrane Proteins ,MESH : Spinal Cord ,Phosphoproteins ,medicine.disease ,MESH : Paraparesis, Tropical Spastic ,MESH : Endothelium, Vascular ,MESH : Membrane Proteins ,Zonula Occludens-1 Protein ,Endothelium, Vascular ,MESH : Phosphoproteins ,030217 neurology & neurosurgery - Abstract
The blood-brain barrier (BBB), which constitutes the interface between blood and cerebral parenchyma, has been shown to be disrupted during retroviral associated neuromyelopathies. Human T cell leukemia virus (HTLV-1)-associated myelopathy/tropical spastic paraparesis is a slowly progressive neurodegenerative disease, in which evidence of BBB breakdown has been demonstrated by the presence of lymphocytic infiltrates in the CNS and plasma protein leakage through cerebral endothelium. Using an in vitro human BBB model, we investigated the cellular and molecular mechanisms involved in endothelial changes induced by HTLV-1-infected lymphocytes. We demonstrate that coculture with infected lymphocytes induces an increase in paracellular endothelial permeability and transcellular migration, via IL-1α and TNF-α secretion. This disruption is associated with tight junction disorganization between endothelial cells, and alterations in the expression pattern of tight junction proteins such as zonula occludens 1. These changes could be prevented by inhibition of the NF-κB pathway or of myosin light chain kinase activity. Such disorganization was confirmed in histological sections of spinal cord from an HTLV-1-associated myelopathy/tropical spastic paraparesis patient. Based on this BBB model, the present data indicate that HTLV-1-infected lymphocytes can induce BBB breakdown and may be responsible for the CNS infiltration that occurs in the early steps of retroviral-associated neuromyelopathies.
- Published
- 2007
23. Localization of anosmin-1a and anosmin-1b in the inner ear and neuromasts of zebrafish
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Sylvain Ernest, Nadia Soussi-Yanicostas, Stéphanie Guadagnini, and Marie-Christine Prévost
- Subjects
Sensory Receptor Cells ,Neurite ,Stereocilia (inner ear) ,Lateral line ,Fluorescent Antibody Technique ,Nerve Tissue Proteins ,Hair Cells, Auditory ,Genetics ,medicine ,Animals ,Inner ear ,Axon ,Microscopy, Immunoelectron ,Molecular Biology ,Zebrafish ,Extracellular Matrix Proteins ,Microscopy, Confocal ,biology ,Kinocilium ,biology.organism_classification ,Immunohistochemistry ,Lateral Line System ,Cell biology ,medicine.anatomical_structure ,Ear, Inner ,Microscopy, Electron, Scanning ,Axon guidance ,sense organs ,Developmental Biology - Abstract
Anosmin-1, encoded by the KAL-1 gene, is the protein defective in the X-linked form of Kallmann syndrome. This human developmental disorder is characterized by defects in cell migration and axon target selection. Anosmin-1 is an extracellular matrix protein that plays a role, in vitro, in processes such as cell adhesion, neurite outgrowth, axon guidance, and axon branching. The zebrafish possesses two orthologues of the KAL-1 gene: kal1a and kal1b, which encode anosmin-1a and anosmin-1b, respectively. Previous in situ hybridization studies have shown that kal1a and kal1b mRNAs are expressed in undetermined cells of the inner ear but not in neuromast cells. Using specific antibodies against anosmin-1a and anosmin-1b, we report here that both proteins are expressed in sensory hair cells of the inner ear cristae ampullaris and the lateral line neuromasts. Accumulation of these proteins was observed mainly at the level of the hair bundle and also at the cell membrane. In neuromast hair cells, immunogold scanning electronmicroscopy demonstrated that anosmin-1a and anosmin-1b were present at the surface of the stereociliary bundle. In addition, anosmin-1a, but not anosmin-1b, was detected on the track of the ampullary nerve. This is the first report of anosmin-1 expression in sensory hair cells of the inner ear and lateral line, and along the ampullary nerve track.
- Published
- 2007
24. Pseudomonas aeruginosa manipulates redox and iron homeostasis of its microbiota partner Aspergillus fumigatus via phenazines
- Author
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Anne Beauvais, Benoit Briard, Jean-Paul Latgé, Gaëtan L. A. Mislin, Virginie Lair, Beatrix E. Lechner, Marie-Christine Prévost, Hubertus Haas, Perrine Bomme, Aspergillus, Institut Pasteur [Paris], Cellule Pasteur, Université Paris Diderot - Paris 7 (UPD7)-PRES Sorbonne Paris Cité, Microscopie ultrastructurale (plate-forme), Innsbruck Medical University [Austria] (IMU), Biotechnologie et signalisation cellulaire (BSC), Université de Strasbourg (UNISTRA)-Institut de recherche de l'Ecole de biotechnologie de Strasbourg (IREBS)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche de Chimie Paris (IRCP), Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Ministère de la Culture (MC), Research in the Aspergillus Unit of JP Latgé was supported by the Association Vaincre La Mucoviscidose (RF20140501052/1/1/141). B.E. Lechner and H. Haas were supported by the FWF project 1346-B21., Institut Pasteur [Paris] (IP), and Innsbruck Medical University = Medizinische Universität Innsbruck (IMU)
- Subjects
Iron ,medicine.disease_cause ,Redox ,Article ,Aspergillus fumigatus ,Microbiology ,03 medical and health sciences ,chemistry.chemical_compound ,Pyocyanin ,Superoxides ,medicine ,Mode of action ,skin and connective tissue diseases ,Reactive nitrogen species ,[SDV.MP.MYC]Life Sciences [q-bio]/Microbiology and Parasitology/Mycology ,030304 developmental biology ,chemistry.chemical_classification ,0303 health sciences ,Reactive oxygen species ,Multidisciplinary ,biology ,030306 microbiology ,Pseudomonas aeruginosa ,Microbiota ,biology.organism_classification ,Sciences du Vivant [q-bio]/Microbiologie et Parasitologie ,Reactive Nitrogen Species ,[SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology ,Biochemistry ,chemistry ,Phenazines ,Oxidation-Reduction ,Function (biology) - Abstract
The opportunistic fungal pathogen Aspergillus fumigatus is increasingly found as a coinfecting agent along with Pseudomonas aeruginosa in cystic fibrosis patients. Amongst the numerous molecules secreted by P. aeruginosa during its growth, phenazines constitute a major class. P. aeruginosa usually secreted four phenazines, pyocyanin (PYO), phenazine-1-carboxamide (PCN), 1-hydroxyphenazine (1-HP) and phenazine-1-carboxylic acid (PCA). These phenazines inhibited the growth of A. fumigatus but the underlying mechanisms and the impact of these four phenazines on A. fumigatus biology were not known. In the present study, we analyzed the functions of the four phenazines and their mode of action on A. fumigatus. All four phenazines showed A. fumigatus growth inhibitory effects by inducing production of reactive oxygen species (ROS), specifically O2·− and reactive nitrogen species (RNS), ONOO−. A. fumigatus Sod2p was the major factor involved in resistance against the ROS and RNS induced by phenazines. Sub-inhibitory concentrations of PYO, PCA and PCN promote A. fumigatus growth by an independent iron-uptake acquisition. Of the four phenazines 1-HP had a redox-independent function; being able to chelate metal ions 1-HP induced A. fumigatus iron starvation. Our data show the fine-interactions existing between A. fumigatus and P. aeruginosa, which can lead to stimulatory or antagonistic effects.
- Published
- 2015
25. Crl Activates Transcription Initiation of RpoS-Regulated Genes Involved in the Multicellular Behavior of Salmonella enterica Serovar Typhimurium
- Author
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Valentin Jaumouillé, Annie Kolb, Christelle Talhouarne, Véronique Robbe-Saule, Stéphanie Guadagnini, Hayette Mathout, Marie-Christine Prévost, and Françoise Norel
- Subjects
Salmonella typhimurium ,Transcription, Genetic ,Operon ,Sigma Factor ,Biology ,medicine.disease_cause ,Microbiology ,Bacterial Proteins ,Transcription (biology) ,Sigma factor ,Escherichia coli ,medicine ,Molecular Biology ,Molecular Biology of Pathogens ,fungi ,food and beverages ,Promoter ,Gene Expression Regulation, Bacterial ,beta-Galactosidase ,biology.organism_classification ,Complementation ,Kinetics ,Microscopy, Electron ,Salmonella enterica ,Salmonella Phages ,rpoS ,Gene Deletion - Abstract
In Salmonella enterica serovar Typhimurium, the stationary-phase sigma factor σ S (RpoS) is required for virulence, stress resistance, biofilm formation, and development of the rdar morphotype. This morphotype is a multicellular behavior characterized by expression of the adhesive extracellular matrix components cellulose and curli fimbriae. The Crl protein of Escherichia coli interacts with σ S and activates expression of σ S -regulated genes, such as the csgBAC operon encoding the subunit of the curli proteins, by an unknown mechanism. Here, we showed using in vivo and in vitro experiments that the Crl protein of Salmonella serovar Typhimurium is required for development of a typical rdar morphotype and for maximal expression of the csgD , csgB , adrA , and bcsA genes, which are involved in curli and cellulose biosynthesis. In vitro transcription assays and potassium permanganate reactivity experiments with purified His 6 -Crl showed that Crl directly activated σ S -dependent transcription initiation at the csgD and adrA promoters. We observed no effect of Crl on σ 70 -dependent transcription. Crl protein levels increased during the late exponential and stationary growth phases in Luria-Beratani medium without NaCl at 28°C. We obtained complementation of the crl mutation by increasing σ S levels. This suggests that Crl has a major physiological impact at low concentrations of σ S .
- Published
- 2006
26. Assembly and role of pili in group B streptococci
- Author
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Mila Kojadinovic, Elise Caliot, Claire Poyart, Isabelle Bonne, Shaynoor Dramsi, Stéphanie Guadagnini, Marie-Christine Prévost, Lila Lalioui, and Patrick Trieu-Cuot
- Subjects
Operon ,Locus (genetics) ,Microbiology ,Bacterial Adhesion ,Pilus ,Streptococcus agalactiae ,03 medical and health sciences ,Bacterial Proteins ,Sortase ,Humans ,Molecular Biology ,030304 developmental biology ,Regulator gene ,Genetics ,0303 health sciences ,biology ,030306 microbiology ,Epithelial Cells ,Aminoacyltransferases ,Bacterial adhesin ,Cysteine Endopeptidases ,Pilus shaft ,Fimbriae, Bacterial ,Pilin ,biology.protein ,Fimbriae Proteins - Abstract
Summary Streptococcus agalactiae [group B streptococcus (GBS)] is the leading cause of neonatal pneumonia, sepsis and meningitis. An in silico genome analysis indicated that GBS strain NEM316 encodes five putative sortases, including the major class A sortase enzyme and four class C sortases. The genes encoding the class C sortases are tandemly arranged in two different loci, srtC1-C2 and srtC3-C4 , with a similar genetic organization and are thought to be involved in pilus biosynthesis. Each pair of sortase genes is flanked by LPXTG protein encoding genes, two upstream and one downstream, and a divergently transcribed regulatory gene located upstream from this locus. We demonstrated that strain NEM316 expresses only the srtC3-C4 locus, which encodes three surface proteins (Gbs1474, Gbs1477 and Gbs1478) that polymerize to form appendages resembling pili. Structural and functional analysis of this locus revealed that: (i) the transcriptional activator RogB is required for expression of the srtC3-C4 operon; (ii) Gbs1477, and either SrtC3 or SrtC4 are absolutely required for pilus biogenesis; and (iii) GBS NEM316 pili are composed of three surface proteins, Gbs1477, the bona fide pilin which is the major component, Gbs1474, a minor associated component, and Gbs1478, a pilus-associated adhesin. Surprisingly, pilus-like structures can be formed in the absence of the two minor components, i.e. the putative anchor Gbs1474 or the adhesin Gbs1478. Adherence assays showed that Gbs1478 confers adhesive capacity to the pilus. This study provides the first evidence that adhesive pili are also present in Grampositive pathogens.
- Published
- 2006
27. AGS3, an α(1–3)glucan synthase gene family member of Aspergillus fumigatus, modulates mycelium growth in the lung of experimentally infected mice
- Author
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J. P. Latgé, D. Maubon, Myriam Tanguy, M. Huerre, S. Park, David S. Perlin, Marie-Christine Prévost, Anne Beauvais, and Christine Schmitt
- Subjects
Antifungal Agents ,Mutant ,Carbohydrates ,Virulence ,Microbiology ,Aspergillus fumigatus ,Fungal Proteins ,Cell wall ,Mice ,Cell Wall ,Morphogenesis ,Genetics ,Animals ,Aspergillosis ,Glucans ,Lung ,Gene ,Mycelium ,Glucan ,Melanins ,chemistry.chemical_classification ,Aspergillus ,biology ,biology.organism_classification ,Disease Models, Animal ,chemistry ,Glucosyltransferases ,Female ,Reactive Oxygen Species ,Gene Deletion - Abstract
The cell wall of human fungal pathogen Aspergillus fumigatus protects the fungus against threats from environment and interacts with the host immune system. Alpha(1-3)glucan is the major polysaccharide of Aspergillus fumigatus cell wall, and it has been shown to contribute to the virulence of diverse fungal pathogens. In A. fumigatus, three putative alpha(1-3)glucan synthase genes AGS1, AGS2 and AGS3 have been identified. AGS1 is responsible for cell wall alpha(1-3)glucan biosynthesis, but strains with deletions of either AGS1 or AGS2 are not defective in virulence [Beauvais, A., Maubon, D., Park, S., Morelle, W., Tanguy, M., Huerre, M., Perlin, D.S., Latgé, J. P., 2005. Two alpha(1-3) glucan synthases with different functions in Aspergillus fumigatus. Appl. Environ. Microbiol. 71, 1531-1538]. In contrast, we present evidence that AGS3 is also responsible for cell wall alpha(1-3)glucan biosynthesis and can modulate the virulence of A. fumigatus. An AGS3 deletion strain was found to produce faster and more robust disease than the parental strain in an experimental mouse model of aspergillosis. The apparent hyper-virulence in the AGS3-deleted mutant was correlated with an increased melanin content of the conidial cell wall, a better resistance to reactive oxygen species and a quicker germination rate. These results suggest an indirect role for AGS3 in virulence through an adaptive mechanism.
- Published
- 2006
28. Muscle Wasting Induced by HTLV-1 Tax-1 Protein
- Author
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Gillian Butler-Browne, Vincent Mouly, Simona Ozden, Antoine Gessain, Marie-Christine Prévost, and Pierre-Emmanuel Ceccaldi
- Subjects
Pathology ,medicine.medical_specialty ,biology ,Myogenesis ,viruses ,Inflammation ,medicine.disease ,biology.organism_classification ,Pathology and Forensic Medicine ,Cell culture ,Human T-lymphotropic virus 1 ,Tropical spastic paraparesis ,medicine ,Myocyte ,Desmin ,medicine.symptom ,Myositis - Abstract
Besides tropical spastic paraparesis/human T-cell leukemia virus type-1 (HTLV-1)-associated myelopathy, the human retrovirus HTLV-1 causes inflammatory disorders such as myositis. Although the pathogenesis of HTLV-1-associated myositis is primarily unknown, a direct effect of cytokines or viral proteins in myocytotoxicity is suspected. We have developed an in vitro cell culture model to study the interactions between primary human muscle cells and HTLV-1 chronically infected cells. When HTLV-1-infected cell lines were added to differentiated muscle cultures, cytopathic changes such as fiber shrinking were observed as early as 1 day after contact. This was accompanied by alterations in desmin and vimentin organization, occurring in the absence of muscle cell infection but with Tax-1 present in myotubes. Cytopathic changes were also observed when infected culture supernatants were added to the muscle cells. Fiber atrophy and cytoskeletal disorganization were confirmed in muscle biopsies from two HTLV-1-infected patients with myositis. Transduction of cultured muscle cells with a lentiviral vector containing the HTLV-1 Tax gene reproduced such effects in vitro. The present data indicate that the myocytotoxicity that is observed in HTLV-1-associated myopathies can be due to a direct effect of the Tax-1 protein expressed in infected inflammatory cells, in the absence of muscle cell infection.
- Published
- 2005
29. Optimization of Virulence Functions Through Glucosylation of Shigella LPS
- Author
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Muriel Delepierre, Nicholas P. West, Philippe J. Sansonetti, Joëlle Mounier, Stéphanie Guadagnini, Ada Prochnicka-Chalufour, Christoph M. Tang, Rachel M. Exley, Myriam Tanguy, Claude Parsot, Marie-Christine Prévost, Centre for Molecular Microbiology and Infection, Faculty of Medicine-Department of Infectious Diseases, Pathogénie Microbienne Moléculaire, Institut Pasteur [Paris]-Institut National de la Santé et de la Recherche Médicale (INSERM), Microscopie électronique (Plate-forme), Institut Pasteur [Paris], Résonance Magnétique Nucléaire des Biomolécules, Institut Pasteur [Paris]-Centre National de la Recherche Scientifique (CNRS), Institut Pasteur [Paris] (IP)-Institut National de la Santé et de la Recherche Médicale (INSERM), Institut Pasteur [Paris] (IP), and Institut Pasteur [Paris] (IP)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
MESH: Operon ,MESH: Mutation ,MESH: Microscopy, Electron, Scanning ,MESH: Shigella flexneri ,MESH: Dysentery, Bacillary ,Lipopolysaccharide ,MESH: Rabbits ,Virulence ,MESH: Neutrophils ,MESH: Virulence ,medicine.disease_cause ,Type three secretion system ,Microbiology ,03 medical and health sciences ,chemistry.chemical_compound ,Antigen ,medicine ,MESH: Animals ,Shigella ,Secretion ,MESH: Bacterial Adhesion ,MESH: Bacteriophages ,MESH: Carbohydrate Conformation ,MESH: O Antigens ,030304 developmental biology ,MESH: Hydrophobicity ,0303 health sciences ,Multidisciplinary ,Innate immune system ,[SDV.BBM.BS]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Structural Biology [q-bio.BM] ,biology ,030306 microbiology ,MESH: Serotyping ,MESH: Glycosylation ,biology.organism_classification ,Enterobacteriaceae ,Virology ,MESH: Glucose ,chemistry ,MESH: Microscopy, Electron, Transmission ,MESH: Intestinal Mucosa ,MESH: Immunity, Innate ,MESH: Lipopolysaccharides - Abstract
Shigella , the leading cause of bacillary dysentery, uses a type III secretion system (TTSS) to inject proteins into human cells, leading to bacterial invasion and a vigorous inflammatory response. The bacterium is protected against the response by the O antigen of lipopolysaccharide (LPS) on its surface. We show that bacteriophage-encoded glucosylation of Shigella O antigen, the basis of different serotypes, shortens the LPS molecule by around half. This enhances TTSS function without compromising the protective properties of the LPS. Thus, LPS glucosylation promotes bacterial invasion and evasion of innate immunity, which may have contributed to the emergence of serotype diversity in Shigella .
- Published
- 2005
30. A lysine- and glutamic acid-rich protein, KERP1, from Entamoeba histolytica binds to human enterocytes
- Author
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Nancy Guillén, Joëlle Mounier, Marie Seigneur, and Marie-Christine Prévost
- Subjects
biology ,Brush border ,Protein subunit ,Immunology ,Lysine ,Lectin ,medicine.disease_cause ,biology.organism_classification ,Microbiology ,Molecular biology ,Intestinal epithelium ,Entamoeba histolytica ,Biochemistry ,Affinity chromatography ,Virology ,parasitic diseases ,biology.protein ,medicine ,Escherichia coli - Abstract
Summary Contact-dependent cytolysis of host cells by Entamoeba histolytica is an important hallmark of amoebiasis that points out the importance of molecules involved in the interaction between the parasite and the human cells. To decipher the molecular and cellular mechanisms supporting the invasion of the intestinal epithelium by E. histolytica, we analysed proteins involved in the interaction of the parasite with enterocytes. Affinity chromatography revealed several amoebic proteins interacting with purified brush border of differentiated Caco2 cells. Among them were found the intermediate subunit of the Gal/GalNAc lectin, an α-actinin-like protein and two new proteins KERP1 and KERP2 rich in lysine and glutamic acid. In silico analysis revealed the presence of KERP2 in the closely related non-pathogenic amoeba species Entamoeba dispar but not of KERP1. In additon, polymerase chain reaction analysis allowed to suggest the absence of kerp1 homologous gene in E. dispar. Therefore, we concentrated on the cellular analysis of KERP1. Cloning of the KERP1-encoding gene, production of a recombinant protein in Escherichia coli and production of a specific antibody allowed us to show the following properties: (i) purified KERP1 binds to epithelial cell surface, (ii) KERP1 is located on the plasma membrane and in vesicles of trophozoites and (iii) KERP1 is delivered in the interstitial area between the trophozoites and the intestinal cells.
- Published
- 2005
31. Ultrastructural analysis of the interactions between Bordetella pertussis, Bordetella parapertussis and Bordetella bronchiseptica and human tracheal epithelial cells
- Author
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Marie-Christine Prévost, Isabelle Bonne, Nicole Guiso, Laurence Bassinet, and Pascale Gueirard
- Subjects
Cytoplasm ,Bordetella pertussis ,Bordetella parapertussis ,Bordetella bronchiseptica ,biology ,Intracellular parasite ,Epithelial Cells ,respiratory system ,biology.organism_classification ,Microbiology ,Bacterial Adhesion ,Trachea ,Bordetella ,Infectious Diseases ,medicine.anatomical_structure ,Microscopy, Electron, Transmission ,medicine ,Humans ,Respiratory epithelium ,Pertactin ,Respiratory tract - Abstract
Bordetella pertussis, Bordetella parapertussis and Bordetella bronchiseptica are respiratory pathogens that colonize the respiratory tract of their host after adhesion to the respiratory epithelium. Presently, the intracellular fate of these bacteria in human tracheal epithelial cells was compared by use of transmission electron microscopy. The three species, even when cytotoxic, were taken-up by epithelial cells. Although, some intracellular bacteria appeared morphologically intact and survived a few days inside epithelial cells, most of them appeared quickly degraded, phenomenon which was associated with an intense cell metabolic activity. Even cytotoxic Bordetella species is ultimately killed by human epithelial cells.
- Published
- 2005
32. Real-time flow cytometry analysis of permeability transition in isolated mitochondria
- Author
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Alain Langonne, Marie-Christine Prévost, Ludwig Baux, Pierre Rustin, Hervé Lecoeur, Dominique Rebouillat, Catherine Brenner, Lena Edelman, and Etienne Jacotot
- Subjects
Cell Membrane Permeability ,Voltage-dependent anion channel ,Mitochondrion ,Mitochondrial Size ,Mitochondrial Membrane Transport Proteins ,Ion Channels ,Membrane Potentials ,Flow cytometry ,Mice ,Mitochondrial membrane transport protein ,medicine ,Animals ,Inner membrane ,Alamethicin ,Fluorescent Dyes ,Membrane potential ,Mice, Inbred BALB C ,biology ,medicine.diagnostic_test ,Mitochondrial Permeability Transition Pore ,Intracellular Membranes ,Cell Biology ,Carbocyanines ,Flow Cytometry ,Mitochondria ,Kinetics ,Biochemistry ,Mitochondrial permeability transition pore ,biology.protein ,Biophysics ,Benzimidazoles ,Calcium - Abstract
Mitochondrial membrane permeabilization (MMP) is a key event in necrotic and (intrinsic) apoptotic processes. MMP is controlled by a few major rate-limiting events, one of which is opening of the permeability transition pore (PTP). Here we develop a flow cytometry (FC)-based approach to screen and study inducers and blockers of MMP in isolated mitochondria. Fixed-time and real-time FC permits to co-evaluate and order modifications of mitochondrial size, structure and inner membrane (IM) electrochemical potential (DeltaPsi(m)) during MMP. Calcium, a major PTP opener, and alamethicin, a PTP-independent MMP inducer, trigger significant mitochondrial forward scatter (FSC) increase and side scatter (SSC) decrease, correlating with spectrophotometrically detected swelling. FC-based fluorescence detection of the DeltaPsi(m)-sensitive cationic lipophilic dye JC-1 permits to detect DeltaPsi(m) variations induced by PTP openers or specific inducers of inner MMP such as carbonylcyanide m-chlorophenylhydrazone (mClCCP). These simple, highly sensitive and quantitative FC-based methods will be pertinent to evaluate compounds for their ability to control MMP.
- Published
- 2004
33. Deficiency in mycolipenate- and mycosanoate-derived acyltrehaloses enhances early interactions of Mycobacterium tuberculosis with host cells
- Author
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Marie-Christine Prévost, Cécile Rousseau, Stéphanie Giroux, Tatiana Sirakova, Brigitte Gicquel, Yann Bordat, Olivier Neyrolles, Pappachan E. Kolattukudy, and Mary Jackson
- Subjects
Tuberculosis ,Tubercle ,Immunology ,Mutant ,Bacillus ,Spleen ,Models, Biological ,Microbiology ,Pathogenesis ,Mycobacterium tuberculosis ,Mice ,Phagocytosis ,Virology ,medicine ,Animals ,Humans ,Lung ,Mice, Inbred BALB C ,biology ,Macrophages ,Fatty Acids ,Polysaccharides, Bacterial ,Trehalose ,biology.organism_classification ,medicine.disease ,medicine.anatomical_structure ,Liver ,Mycolic Acids ,Mutation ,Female ,Glycolipids ,Cell envelope ,HeLa Cells - Abstract
Summary Lipids that are uniquely found in the cell envelope of pathogenic mycobacteria, such as those containing multiple methyl-branched long-chain fatty acids, have long been thought to play a role in host–pathogen interactions. The recent construction by Dubey et al. (2002) Mol Microbiol 45: 1451–1459, of a Mycobacterium tuberculosis mutant that is deficient in the synthesis of the di- and tri-methylbranched fatty acids, mycolipenates and mycosanoates, found in some forms of diacyltrehaloses (DAT) and polyacyltrehaloses (PAT) provided the opportunity to assess the contribution of these complex lipids to pathogenesis directly. We provide evidence that DAT/PAT deficiency affects the surface global composition of the mycobacterial cell envelope improving the efficiency with which M. tuberculosis binds to and enters phagocytic and non-phagocytic host cells. Interestingly, this property did not affect the overall replication and persistence of the tubercle bacillus in the lungs, spleen and liver of mice infected via the respiratory or intravenous route.
- Published
- 2003
34. A Chimeric Human T-Cell Lymphotropic Virus Type 1 with the Envelope Glycoprotein of Moloney Murine Leukemia Virus Is Infectious for Murine Cells
- Author
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Marie-Christine Prévost, Karin Pramberger, Frédéric Tangy, Frédéric Delebecque, and Michel Brahic
- Subjects
CD4-Positive T-Lymphocytes ,Recombinant Fusion Proteins ,viruses ,Molecular Sequence Data ,Immunology ,Transfection ,Microbiology ,3T3 cells ,Mice ,Proviruses ,Viral Envelope Proteins ,hemic and lymphatic diseases ,Virology ,Murine leukemia virus ,medicine ,Animals ,Humans ,Amino Acid Sequence ,Lymphocytes ,Human T cell lymphotropic virus type 1 ,chemistry.chemical_classification ,Infectivity ,Human T-lymphotropic virus 1 ,biology ,3T3 Cells ,Provirus ,biology.organism_classification ,Molecular biology ,Virus-Cell Interactions ,medicine.anatomical_structure ,chemistry ,Insect Science ,Moloney murine leukemia virus ,Glycoprotein - Abstract
We constructed a chimeric human T-cell lymphotropic virus type 1 (HTLV-1) provirus in which the original envelope precursor sequence was replaced by that of ecotropic Moloney murine leukemia virus (Mo-MuLV). Chimeric particles produced by transient transfection of this chimeric provirus were infectious for murine cells, such as NIH 3T3 fibroblasts, lymphoid EL4 cells, and primary CD4 + T lymphocytes, whereas HTLV-1 particles were not. The infectivity of chimeric particles increased 10 times when the R peptide located at the carboxy terminus of the MuLV envelope glycoprotein was deleted. Primary murine CD4 + T lymphocytes, infected by the ΔR chimeric virus, released particles that could spread the infection to other naive murine lymphoid cells. This chimeric virus, with the Mo-MuLV envelope glycoprotein and the replication characteristics of HTLV-1, should be useful in studying the pathogenesis of HTLV-1 in a mouse model.
- Published
- 2002
35. Are the PE-PGRS proteins of Mycobacterium tuberculosis variable surface antigens?
- Author
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Marie-Christine Prévost, Dana J. Philpott, Stewart T. Cole, Nadine Honoré, Brigitte Saint-Joanis, and Sayera Banu
- Subjects
Immunoelectron microscopy ,Biology ,biology.organism_classification ,Microbiology ,Epitope ,Mycobacterium tuberculosis ,Blot ,Plasmid ,Antigen ,biology.protein ,Antibody ,Molecular Biology ,Gene - Abstract
Mycobacterium tuberculosis H37Rv contains 67 PE-PGRS genes, with multiple tandem repetitive sequences, encoding closely related proteins that are exceptionally rich in glycine and alanine. As no functional information was available, 10 of these genes were selected and shown to be expressed in vitro by reverse transcription-polymerase chain reaction (RT-PCR). Antibodies against five PE-PGRS proteins, raised in mice by DNA vaccination, detected single proteins when the same plasmid constructs used for immunization were expressed in epithelial cells or in reticulocyte extracts, confirming that the PE-PGRS proteins are antigenic. As expected from the conserved repetitive structure, the antibodies cross-reacted with more than one PE-PGRS protein, suggesting that different proteins share common epitopes. PE-PGRS proteins were detected by West-ern blotting in five different mycobacterial species (M. tuberculosis, M. bovis BCG, M. smegmatis, M. marinum and M. gordonae) and 11 clinical isolates of M. tuberculosis. Whole-genome comparisons of M. tuberculosis predicted allelic diversity in the PE-PGRS family, and this was confirmed by immunoblot studies as size variants were detected in clinical strains. Subcellular fractionation studies and immunoelectron microscopy localized many PE-PGRS proteins in the cell wall and cell membrane of M. tuberculosis. The data suggest that some PE-PGRS proteins are variable surface antigens.
- Published
- 2002
36. ZapE Is a Novel Cell Division Protein Interacting with FtsZ and Modulating the Z-Ring Dynamics
- Author
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Jean-Michel Betton, Philippe J. Sansonetti, Andy Fenton, Benoit S. Marteyn, Nicholas P. West, Anastasia D. Gazi, Gouzel Karimova, Lhousseine Touqui, Marie-Christine Prévost, Kenn Gerdes, Daniel Ladant, Christoph M. Tang, and Oemer Poyraz
- Subjects
Cell division ,ATPase ,Plasma protein binding ,medicine.disease_cause ,Microbiology ,Bacterial cell structure ,03 medical and health sciences ,Bacterial Proteins ,Virology ,Protein Interaction Mapping ,Escherichia coli ,medicine ,FtsZ ,030304 developmental biology ,Adenosine Triphosphatases ,0303 health sciences ,biology ,030306 microbiology ,Escherichia coli Proteins ,Divisome complex ,QR1-502 ,In vitro ,Cell biology ,Cytoskeletal Proteins ,biology.protein ,Cell Division ,Research Article ,Protein Binding - Abstract
Bacterial cell division requires the formation of a mature divisome complex positioned at the midcell. The localization of the divisome complex is determined by the correct positioning, assembly, and constriction of the FtsZ ring (Z-ring). Z-ring constriction control remains poorly understood and (to some extent) controversial, probably due to the fact that this phenomenon is transient and controlled by numerous factors. Here, we characterize ZapE, a novel ATPase found in Gram-negative bacteria, which is required for growth under conditions of low oxygen, while loss of zapE results in temperature-dependent elongation of cell shape. We found that ZapE is recruited to the Z-ring during late stages of the cell division process and correlates with constriction of the Z-ring. Overexpression or inactivation of zapE leads to elongation of Escherichia coli and affects the dynamics of the Z-ring during division. In vitro, ZapE destabilizes FtsZ polymers in an ATP-dependent manner., IMPORTANCE Bacterial cell division has mainly been characterized in vitro. In this report, we could identify ZapE as a novel cell division protein which is not essential in vitro but is required during an infectious process. The bacterial cell division process relies on the assembly, positioning, and constriction of FtsZ ring (the so-called Z-ring). Among nonessential cell division proteins recently identified, ZapE is the first in which detection at the Z-ring correlates with its constriction. We demonstrate that ZapE abundance has to be tightly regulated to allow cell division to occur; absence or overexpression of ZapE leads to bacterial filamentation. As zapE is not essential, we speculate that additional Z-ring destabilizing proteins transiently recruited during late cell division process might be identified in the future.
- Published
- 2014
37. Oncosis is associated with exposure of phosphatidylserine residues on the outside layer of the plasma membrane: A reconsideration of the specificity of the annexin V/propidium iodide assay
- Author
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Hervé Lecoeur, Marie-Christine Prévost, and Marie-Lise Gougeon
- Subjects
Programmed cell death ,Necrosis ,medicine.diagnostic_test ,Biophysics ,Cell Biology ,Hematology ,Phosphatidylserine ,Biology ,Molecular biology ,Jurkat cells ,Pathology and Forensic Medicine ,Flow cytometry ,Cell biology ,chemistry.chemical_compound ,Endocrinology ,chemistry ,Annexin ,Apoptosis ,medicine ,Propidium iodide ,medicine.symptom - Abstract
Background Following a lethal injury, two modes of cell death can be distinguished, apoptosis and primary necrosis. Cells pass through a prelethal stage characterized by a preservation of membrane integrity, in which they shrink (apoptosis) or swell (oncosis, the early phase of primary necrosis). During apoptosis, a loss of phospholipid asymmetry leads to exposure of phosphatidylserine (PS) residues on the outer leaflet of the plasma membrane. We examined whether the external PS exposure, initially supposed to be specific for apoptosis, was also observed in oncotic cells. Methods Human peripheral lymphocytes, Jurkat T cells, U937 cells, or HeLa cells were submitted to either apoptotic or oncotic stimuli. PS external exposure was assessed after binding of FITC-conjugated annexin V as was the loss of membrane integrity after propidium iodide (PI) uptake. Morphological examination was performed by optical or electron microscopy. Results Similarly to apoptotic cells, oncotic cells expose external PS residues while preserving membrane integrity. Consequently, oncotic cells exhibit the annexin V+ PI- phenotype, previously considered to be specific for apoptotic cells. Conclusions This study concludes that the annexin V/PI assay does not discriminate between apoptosis and oncosis and that it can be a useful tool to study oncosis by flow cytometry. Cytometry 44:65–72, 2001. © 2001 Wiley-Liss, Inc.
- Published
- 2001
38. Mitochondrio‐nuclear translocation of AIF in apoptosis and necrosis
- Author
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Eric Daugas, Josef M. Penninger, Karine F. Ferri, Naoufal Zamzami, Santos A. Susin, Marie-Christine Prévost, Brian Leber, Guido Kroemer, Theano Irinopoulou, Nathanael Larochette, and David W. Andrews
- Subjects
Programmed cell death ,Caspase-Independent Apoptosis ,Mitochondrion ,Biology ,Biochemistry ,Cell biology ,Apoptosis ,Genetics ,DNA fragmentation ,Inner membrane ,Apoptosis-inducing factor ,cardiovascular diseases ,biological phenomena, cell phenomena, and immunity ,Intermembrane space ,Molecular Biology ,Biotechnology - Abstract
Apoptosis inducing factor (AIF) is a novel apoptotic effector protein that induces chromatin condensation and large-scale (∼50 kbp) DNA fragmentation when added to purified nuclei in vitro. Confocal and electron microscopy reveal that, in normal cells, AIF is strictly confined to mitochondria and thus colocalizes with heat shock protein 60 (hsp60). On induction of apoptosis by staurosporin, c-Myc, etoposide, or ceramide, AIF (but not hsp60) translocates to the nucleus. This suggests that only the outer mitochondrial membrane (which retains AIF in the intermembrane space) but not the inner membrane (which retains hsp60 in the matrix) becomes protein permeable. The mitochondrio-nuclear redistribution of AIF is prevented by a Bcl-2 protein specifically targeted to mitochondrial membranes. The pan-caspase inhibitor Z-VAD.fmk does not prevent the staurosporin-induced translocation of AIF, although it does inhibit oligonucleosomal DNA fragmentation and arrests chromatin condensation at an early stage. ATP deple...
- Published
- 2000
39. Mycoplasma penetransBacteremia and Primary Antiphospholipid Syndrome1
- Author
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Encarnación Alonso, H L Watson, Alain Blanchard, Gail H. Cassell, Marie-Christine Prévost, Jorge Rojas, Lilia Cedillo, Olivier Neyrolles, and Antonio Yáñez
- Subjects
Microbiology (medical) ,biology ,Epidemiology ,business.industry ,virus diseases ,medicine.disease ,biology.organism_classification ,Primary antiphospholipid syndrome ,Microbiology ,Pathogenesis ,Mycoplasma penetrans ,Infectious Diseases ,medicine.anatomical_structure ,Antiphospholipid syndrome ,Throat ,Bacteremia ,Immunology ,medicine ,Etiology ,Research article ,business - Abstract
Mycoplasma penetrans, a rare bacterium so far only found in HIV-infected persons, was isolated in the blood and throat of a non-HIV-infected patient with primary antiphospholipid syndrome (whose etiology and pathogenesis are unknown).
- Published
- 1999
40. Mitochondrial Release of Caspase-2 and -9 during the Apoptotic Process
- Author
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Isabel Marzo, Santos A. Susin, Guido Kroemer, Catherine Brenner, Pedro M. Alzari, Hans K. Lorenzo, Marie-Christine Prévost, Nathanael Larochette, Naoufal Zamzami, Unite de Génétique Moléculaire et de Biologie du Développement, Centre National de la Recherche Scientifique (CNRS), Biochimie Structurale, Institut Pasteur [Paris] (IP)-Centre National de la Recherche Scientifique (CNRS), Université de Technologie de Compiègne (UTC), Oncologie virale, Centre National de la Recherche Scientifique (CNRS)-Institut Pasteur [Paris], and Institut Pasteur [Paris]-Centre National de la Recherche Scientifique (CNRS)
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Apoptosis ,Mitochondrion ,MESH: Microinjections ,MESH: Caspase 9 ,Mitochondrial apoptosis-induced channel ,MESH: Recombinant Proteins ,Mice ,MESH: Enzyme Precursors ,0302 clinical medicine ,MESH: Caspase 2 ,Immunology and Allergy ,MESH: Animals ,MESH: Flavoproteins ,programmed cell death ,Caspase ,Caspase-9 ,Enzyme Precursors ,Mice, Inbred BALB C ,0303 health sciences ,[SDV.BBM.BS]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Structural Biology [q-bio.BM] ,biology ,Cytochrome c ,Caspase 2 ,Apoptosis Inducing Factor ,Nuclear Proteins ,Articles ,Caspase 9 ,Recombinant Proteins ,Mitochondria ,Cell biology ,MESH: Intracellular Membranes ,Proto-Oncogene Proteins c-bcl-2 ,Caspases ,030220 oncology & carcinogenesis ,Apoptosis-inducing factor ,Female ,MESH: Membrane Proteins ,permeability transition ,MESH: Enzyme Activation ,Microinjections ,MESH: Mitochondria ,caspase ,[PHYS.PHYS.PHYS-BIO-PH]Physics [physics]/Physics [physics]/Biological Physics [physics.bio-ph] ,Immunology ,MESH: Mice, Inbred BALB C ,Cytochrome c Group ,[SDV.BC]Life Sciences [q-bio]/Cellular Biology ,Cysteine Proteinase Inhibitors ,Cell Line ,MESH: Cysteine Proteinase Inhibitors ,03 medical and health sciences ,[CHIM.CRIS]Chemical Sciences/Cristallography ,Animals ,Humans ,Bcl-2 ,[SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology ,MESH: Mice ,030304 developmental biology ,MESH: Caspases ,MESH: Humans ,Flavoproteins ,MESH: Apoptosis ,Membrane Proteins ,Intracellular Membranes ,MESH: Cell Line ,Enzyme Activation ,MESH: Apoptosis Inducing Factor ,MESH: Proto-Oncogene Proteins c-bcl-2 ,biology.protein ,[INFO.INFO-BI]Computer Science [cs]/Bioinformatics [q-bio.QM] ,MESH: Nuclear Proteins ,MESH: Female ,MESH: Cytochrome c Group - Abstract
International audience; The barrier function of mitochondrial membranes is perturbed early during the apoptotic process. Here we show that the mitochondria contain a caspase-like enzymatic activity cleaving the caspase substrate Z-VAD.afc, in addition to three biological activities previously suggested to participate in the apoptotic process: (a) cytochrome c; (b) an apoptosis-inducing factor (AIF) which causes isolated nuclei to undergo apoptosis in vitro; and (c) a DNAse activity. All of these factors, which are biochemically distinct, are released upon opening of the permeability transition (PT) pore in a coordinate, Bcl-2-inhibitable fashion. Caspase inhibitors fully neutralize the Z-VAD.afc-cleaving activity, have a limited effect on the AIF activity, and have no effect at all on the DNase activities. Purification of proteins reacting with the biotinylated caspase substrate Z-VAD, immunodetection, and immunodepletion experiments reveal the presence of procaspase-2 and -9 in mitochondria. Upon induction of PT pore opening, these procaspases are released from purified mitochondria and become activated. Similarly, upon induction of apoptosis, both procaspases redistribute from the mitochondrion to the cytosol and are processed to generate enzymatically active caspases. This redistribution is inhibited by Bcl-2. Recombinant caspase-2 and -9 suffice to provoke full-blown apoptosis upon microinjection into cells. Altogether, these data suggest that caspase-2 and -9 zymogens are essentially localized in mitochondria and that the disruption of the outer mitochondrial membrane occurring early during apoptosis may be critical for their subcellular redistribution and activation.
- Published
- 1999
41. Bax and Adenine Nucleotide Translocator Cooperate in the Mitochondrial Control of Apoptosis
- Author
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Shigemi Matsuyama, Helena L. A. Vieira, John C. Reed, Naoufal Zamzami, Marie Christine Prévost, Isabel Marzo, Santos A. Susin, Catherine Brenner, Zhihua Xie, Guido Kroemer, and Juliane M. Jürgensmeier
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Pore complex ,Programmed cell death ,Apoptosis ,Saccharomyces cerevisiae ,Atractyloside ,Mitochondrion ,Transfection ,Permeability ,Mice ,Bcl-2-associated X protein ,Adenine nucleotide ,Proto-Oncogene Proteins ,Animals ,Humans ,Rats, Wistar ,Inner mitochondrial membrane ,bcl-2-Associated X Protein ,Binding Sites ,Multidisciplinary ,biology ,Adenine nucleotide translocator ,Intracellular Membranes ,Recombinant Proteins ,ANT ,Mitochondria ,Rats ,Cell biology ,Mice, Inbred C57BL ,Proto-Oncogene Proteins c-bcl-2 ,Biochemistry ,Liposomes ,Cyclosporine ,biology.protein ,Bongkrekic Acid ,Dimerization ,HT29 Cells ,Mitochondrial ADP, ATP Translocases - Abstract
The proapoptotic Bax protein induces cell death by acting on mitochondria. Bax binds to the permeability transition pore complex (PTPC), a composite proteaceous channel that is involved in the regulation of mitochondrial membrane permeability. Immunodepletion of Bax from PTPC or purification of PTPC from Bax-deficient mice yielded a PTPC that could not permeabilize membranes in response to atractyloside, a proapoptotic ligand of the adenine nucleotide translocator (ANT). Bax and ANT coimmunoprecipitated and interacted in the yeast two-hybrid system. Ectopic expression of Bax induced cell death in wild-type but not in ANT-deficient yeast. Recombinant Bax and purified ANT, but neither of them alone, efficiently formed atractyloside-responsive channels in artificial membranes. Hence, the proapoptotic molecule Bax and the constitutive mitochondrial protein ANT cooperate within the PTPC to increase mitochondrial membrane permeability and to trigger cell death.
- Published
- 1998
42. A missense mutation in the αB-crystallin chaperone gene causes a desmin-related myopathy
- Author
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Anne Caron, Denise Paulin, Fernando M.S. Tomé, Armelle Faure, Pascale Guicheney, Danielle Chateau, Zhenlin Li, Marie-Christine Prévost, Jean-Marie Dupret, Michel Fardeau, Patrick Vicart, and Françoise Chapon
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Genetic Markers ,Male ,Molecular Sequence Data ,Alpha-Crystallin A Chain ,Biology ,Polymerase Chain Reaction ,Cell Line ,Desmin ,Muscular Diseases ,Crystallin ,Cricetinae ,Genetics ,medicine ,Animals ,Humans ,Myocyte ,Missense mutation ,Cloning, Molecular ,Microscopy, Immunoelectron ,Muscle, Skeletal ,Myopathy ,Heat-Shock Proteins ,Polymorphism, Single-Stranded Conformational ,Chaperone Gene ,Base Sequence ,Skeletal muscle ,Crystallins ,Molecular biology ,Recombinant Proteins ,Pedigree ,medicine.anatomical_structure ,Mutation ,Female ,sense organs ,Lod Score ,medicine.symptom ,Molecular Chaperones - Abstract
Desmin-related myopathies (DRM) are inherited neuromuscular disorders characterized by adult onset and delayed accumulation of aggregates of desmin, a protein belonging to the type III intermediate filament family, in the sarcoplasma of skeletal and cardiac muscles. In this paper, we have mapped the locus for DRM in a large French pedigree to a 26-cM interval in chromosome 11q21-23. This region contains the alphaB-crystallin gene (CRYAB), a candidate gene encoding a 20-kD protein that is abundant in lens and is also present in a number of non-ocular tissues, including cardiac and skeletal muscle. AlphaB-crystallin is a member of the small heat shock protein (shsp) family and possesses molecular chaperone activity. We identified an R120G missense mutation in CRYAB that co-segregates with the disease phenotype in this family. Muscle cell lines transfected with the mutant CRYAB cDNA showed intracellular aggregates that contain both desmin and alphaB-crystallin as observed in muscle fibers from DRM patients. These results are the first to identify a defect in a molecular chaperone as a cause for an inherited human muscle disorder.
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- 1998
43. Identification of two glycosylated components of Mycoplasma penetrans: a surface-exposed capsular polysaccharide and a glycolipid fraction
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Olivier Neyrolles, Catherine Brenner, Thierry Fontaine, Marie-Christine Prévost, Luc Montagnier, and Alain Blanchard
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Ruthenium red ,medicine.disease_cause ,Microbiology ,Silver proteinate ,chemistry.chemical_compound ,Glycolipid ,Mycoplasma penetrans ,medicine ,Humans ,Coloring Agents ,Bacterial Capsules ,biology ,Capsule ,Mycoplasma ,Periodic Acid-Schiff Reaction ,Proteinase K ,biology.organism_classification ,Ruthenium Red ,Staining ,Microscopy, Electron ,chemistry ,Ferritins ,biology.protein ,Electrophoresis, Polyacrylamide Gel ,Endopeptidase K ,Glycolipids ,Glycoconjugates - Abstract
Among the wall-less mycoplasmas only a few species have been identified with a capsule at their cell surface. Mycoplasma penetrans is a recently identified mycoplasma with unique morphology, isolated from HIV-infected patients. Using transmission electron microscopy, it was found that M. penetrans is surrounded by capsular material 11 nm (strain GTU-54-6A1) to 30 nm (strain HF-2) thick, which can be stained with ruthenium red and labelled with cationized ferritin. The polysaccharide composition of this capsule was indicated by its staining with periodic acid-thiocarbohydrazide silver proteinate and the abolition of ruthenium red staining of the cell surface by neuraminidase treatment. In addition, proteinase K treatment of the M. penetrans cells resulted in removal of the capsule, suggesting that polypeptides may contribute in anchoring it to the membrane or in its stability. Two different types of glycosylated material were detected in mycoplasma extracts by SDS-PAGE and periodic acid-Schiff staining. The first component was a high-molecular-mass material, which was heat- and proteinase-K-labile and which probably constitutes the capsular polymer. The other component was a low-molecular-mass glycolipid fraction, which was proteinase-K-, heat- and EDTA-resistant. The identification of a capsule at the M. penetrans cell surface is of particular interest for a mycoplasma which has been shown to adhere to various host cells and to penetrate into their intracellular compartments. The capsule may have significance in the pathogenesis of disease associated with infection by this organism.
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- 1998
44. Strategies for phenotyping apoptotic peripheral human lymphocytes comparing ISNT, annexin-V and 7-AAD cytofluorometric staining methods
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Marie-Christine Prévost, Marie-Lise Gougeon, Hervé Lecoeur, and Eric Ledru
- Subjects
CD8 Antigens ,Antigens, CD19 ,Immunology ,Population ,Apoptosis ,HIV Infections ,Biology ,Peripheral blood mononuclear cell ,CD19 ,Immunophenotyping ,Flow cytometry ,chemistry.chemical_compound ,Antigen ,Annexin ,medicine ,Humans ,Immunology and Allergy ,Fluorometry ,Lymphocytes ,Annexin A5 ,education ,Fluorescent Dyes ,education.field_of_study ,medicine.diagnostic_test ,Phosphatidylserine ,Avidin ,Molecular biology ,Lymphocyte Subsets ,chemistry ,CD4 Antigens ,Dactinomycin ,biology.protein ,Fluorescein-5-isothiocyanate - Abstract
The present article compares the reliability of four previously described cytofluorometric methods of apoptosis quantification for phenotyping apoptotic human lymphocytes. Each of these assays detects distinct cellular alterations of the apoptotic process. Alteration in plasma membrane integrity can be evaluated following 7-AAD incorporation and the translocation of phosphatidylserine from the inner to the outer layer of the plasma membrane can be detected through the FITC–annexin V staining. DNA strand breaks in apoptotic nuclei can be evidenced by the ISNT assay and finally morphological modifications can be followed with FSC/SSC criteria. Comparative analysis of apoptosis in cultured PBMC from HIV-infected patients considering the FSC/SSC parameters, 7-AAD stainability and annexin V fixation revealed that the latter identifies early apoptotic cells, also characterized as 7-AADlow with a reduced FSC. Moreover these three methods proved to be reliable and gave statistically similar results when combined with cell surface detection of antigens such as CD4, CD8 and CD19 by specific mAbs. Importantly, the 7-AAD assay easily allowed the identification of debris/apoptotic bodies, which were still stained by anti-cell surface mAbs and might therefore significantly distort the apoptosis percentage in a given lymphocyte subset. In the present report we also point out that the ISNT assay is not appropriate for phenotyping apoptotic lymphocytes in PBMC. Indeed it can particularly underestimate the rate of apoptosis in the B-cell subset. This was found to be related to the apoptosis-associated decrease in cell surface antigen expression, which is dramatically exacerbated in the ISNT assay because of the stripper effect of ethanol used for cell permeabilization. Finally, we propose a three step analytical strategy to accurately phenotype apoptotic peripheral human lymphocytes. It includes two gating steps performed on FSC/SSC criteria and 7-AAD/FSC parameters to eliminate monocytes, granulocytes and debris-apoptotic bodies, the third step being the phenotyping step itself, performed in dual or triple staining experiments. Altogether these observations emphasize that it is essential to assess critically the ability of a cytofluorometric method to phenotype apoptotic cells in complex lymphoid populations and that inaccurate identification of cell subsets undergoing apoptosis can be readily overcome by gating properly the lymphoid population, and using assays which preserve cell surface structure.
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- 1997
45. Species-specific impact of the autophagy machinery on Chikungunya virus infection
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Nicolas Gangneux, Mickaël Lelek, Marie-Christine Prévost, Mehdi Bouraï, Yves Jacob, Pierre-Olivier Vidalain, Thérèse Couderc, Marc Lecuit, Marianne Lucas-Hourani, Serge Mostowy, Christophe Zimmer, Delphine Judith, Philippe Pierre, Nadège Cayet, Frédéric Tangy, Biologie des Infections - Biology of Infection, Institut Pasteur [Paris]-Institut National de la Santé et de la Recherche Médicale (INSERM), Interactions Bactéries-Cellules (UIBC), Institut National de la Recherche Agronomique (INRA)-Institut Pasteur [Paris]-Institut National de la Santé et de la Recherche Médicale (INSERM), Génomique Virale et Vaccination, Institut Pasteur [Paris]-Centre National de la Recherche Scientifique (CNRS), Imagerie et Modélisation, Microscopie Ultrastructurale (Plate-forme), Génétique, Papillomavirus et Cancer Humain, Institut Pasteur [Paris], Centre d'Immunologie de Marseille - Luminy (CIML), Aix Marseille Université (AMU)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Université Paris Descartes - Paris 5 (UPD5), Institut Necker Enfants-Malades (INEM - UM 111 (UMR 8253 / U1151)), Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), This work was supported by Institut Pasteur, FRM, Ville de Paris, Fondation BNP‐Paribas, ICRES FP7, LabEx IBEID and the Programme Interdisciplinaire CNRS Maladies Infectieuses Emergentes. D.J. was supported by a doctoral fellowship from the Axa Research Fund and M.B. by a doctoral fellowship from Région Ile‐de‐France., We are grateful to S. Higgs for providing CHIKV cDNA clones and to N. Mizushima for providing Atg5−/− and Atg5+/+ MEFs. We thank V. Sancho‐Shimizu, C. Prehault, M. Hamon, L. Radoshevich, P. Desprès, A. Merits, V. Meas‐Yedid Hardy, E. Meurs and A. Dufour for their generous gift of reagents or technical advices. We also thank members of the Biology of Infection Unit, F. Rey, P. Cossart and P. Codogno, for their helpful discussions and critical reading of the manuscript., Institut Pasteur [Paris] (IP)-Institut National de la Santé et de la Recherche Médicale (INSERM), Institut National de la Recherche Agronomique (INRA)-Institut Pasteur [Paris] (IP)-Institut National de la Santé et de la Recherche Médicale (INSERM), Institut Pasteur [Paris] (IP)-Centre National de la Recherche Scientifique (CNRS), Institut Pasteur [Paris] (IP), Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut Pasteur [Paris]-Institut National de la Recherche Agronomique (INRA), and Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)
- Subjects
MESH: Virus Replication ,viruses ,MESH: Adaptor Proteins, Signal Transducing/metabolism ,MESH: Chikungunya Fever ,Viral Nonstructural Proteins ,MESH: Chikungunya virus/physiology ,medicine.disease_cause ,Virus Replication ,Biochemistry ,Upfront ,Mice ,Ubiquitin ,Phagosomes ,Sequestosome-1 Protein ,MESH: Sequestosome-1 Protein ,NDP52 ,MESH: Animals ,Chikungunya ,Nuclear protein ,0303 health sciences ,MESH: Viral Nonstructural Proteins/metabolism ,biology ,MESH: Phagosomes/virology ,p62 ,Nuclear Proteins ,virus diseases ,3. Good health ,Cell biology ,Protein Transport ,MESH: Phagosomes/metabolism ,Capsid ,Host-Pathogen Interactions ,MESH: Immunity, Innate ,MESH: Capsid/metabolism ,Microtubule-Associated Proteins ,Chikungunya virus ,Protein Binding ,autophagy ,MESH: Protein Transport ,MESH: Alphavirus Infections/virology ,Virus ,03 medical and health sciences ,parasitic diseases ,Genetics ,medicine ,Animals ,Humans ,MESH: Species Specificity ,MESH: Protein Binding ,MESH: Autophagy ,MESH: Nuclear Proteins/metabolism ,Molecular Biology ,MESH: Mice ,030304 developmental biology ,Adaptor Proteins, Signal Transducing ,Sirolimus ,MESH: Humans ,030306 microbiology ,Alphavirus Infections ,Autophagy ,Scientific Reports ,MESH: Host-Pathogen Interactions ,Virology ,Immunity, Innate ,MESH: Sirolimus/pharmacology ,species specificity ,Viral replication ,MESH: HeLa Cells ,MESH: Microtubule-Associated Proteins/metabolism ,biology.protein ,Chikungunya Fever ,[SDV.SPEE]Life Sciences [q-bio]/Santé publique et épidémiologie ,HeLa Cells - Abstract
Comment in : Macroautophagy--friend or foe of viral replication? [EMBO Rep. 2013]; International audience; Chikungunya virus (CHIKV) is a recently re-emerged arbovirus that triggers autophagy. Here, we show that CHIKV interacts with components of the autophagy machinery during its replication cycle, inducing a cytoprotective effect. The autophagy receptor p62 protects cells from death by binding ubiquitinated capsid and targeting it to autophagolysosomes. By contrast, the human autophagy receptor NDP52-but not its mouse orthologue-interacts with the non-structural protein nsP2, thereby promoting viral replication. These results highlight the distinct roles of p62 and NDP52 in viral infection, and identify NDP52 as a cellular factor that accounts for CHIKV species specificity.
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- 2013
46. SUN proteins belong to a novel family of β-(1,3)-glucan-modifying enzymes involved in fungal morphogenesis
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Christine Schmitt, Christophe d'Enfert, Audrey Nesseir, Anne Beauvais, Patrick England, Vishukumar Aimanianda, Rémi Beau, Arnaud Firon, Marie-Christine Prévost, Amandine Gastebois, Sophie Bachellier-Bassi, Jean-Paul Latgé, Isabelle Mouyna, Aspergillus, Institut Pasteur [Paris], Biologie et Pathogénicité fongiques, Institut Pasteur [Paris]-Institut National de la Recherche Agronomique (INRA), Microscopie ultrastructurale (plate-forme), Biochimie et Biophysique des Macromolécules (Plate-forme), Institut Pasteur [Paris]-Centre National de la Recherche Scientifique (CNRS), This work was supported by grants from the European Commission (Galar Fungail 2, MRTN-CT-2003-504148, FINSysB, PITN-GA-2008-214004) (to C. d. E.) and the European Science Foundation (ESF) Fuminomics, Partenariat Sanofi-aventis-Aviesan (ITMO Maladies Infectieuses, Sanofi Aventis Research & Development TSU ID (SAR&D) TSU ID/Sanofi-Pasteur), and Agence Nationale de Recherches (ANR) (Grant 09-BLAN-0287) (to J. P. L.), ANR-09-BLAN-0287,REMODELE,Nouvelles voies métaboliques essentielles pour la biosynthèse de la paroi des champignons(2009), European Project: 214004,PEOPLE,FP7-PEOPLE-2007-1-1-ITN,FINSYSB(2008), Institut Pasteur [Paris] (IP), Biologie et Pathogénicité fongiques (BPF), Institut National de la Recherche Agronomique (INRA)-Institut Pasteur [Paris] (IP), Institut Pasteur [Paris] (IP)-Centre National de la Recherche Scientifique (CNRS), Institut National de la Recherche Agronomique (INRA)-Institut Pasteur [Paris], Biophysique des macromolécules et de leurs interactions, ANR Grant 09-BLAN-0287,ANR Grant 09-BLAN-0287,Grant 09-BLAN-0287, Institut National de la Recherche Agronomique (INRA) - Institut Pasteur [Paris], Microscopie ultrastructurale - Ultrapole (CITECH), Biophysique des macromolécules et leurs interactions, and Institut Pasteur [Paris] - Centre National de la Recherche Scientifique (CNRS)
- Subjects
Hyphal growth ,MESH : Spores, Fungal ,MESH : Molecular Sequence Data ,Glycosylation ,MESH: Sequence Homology, Amino Acid ,Conidiation ,Gene Expression ,Oligosaccharides ,Glycobiology and Extracellular Matrices ,MESH: Amino Acid Sequence ,Biochemistry ,Aspergillus fumigatus ,Cell Wall ,Gene Expression Regulation, Fungal ,Candida albicans ,Morphogenesis ,MESH : Fungal Proteins ,skin and connective tissue diseases ,[SDV.MP.MYC]Life Sciences [q-bio]/Microbiology and Parasitology/Mycology ,0303 health sciences ,integumentary system ,MESH : Amino Acid Sequence ,Hydrolysis ,MESH : Glycosylation ,Glucan Hydrolase Activity ,SUN ,MESH : Protein Binding ,MESH : Glycoside Hydrolases ,Spores, Fungal ,MESH: Glycosylation ,MESH : Sequence Homology, Amino Acid ,Cell biology ,[SDV] Life Sciences [q-bio] ,Aspergillus ,CELL-WALL BIOGENESIS ,MOTOR-LIKE DOMAIN ,ASPERGILLUS-FUMIGATUS ,CANDIDA-ALBICANS ,SCHIZOSACCHAROMYCES-POMBE ,SACCHAROMYCES-CEREVISIAE ,BIOFILM FORMATION ,BETA-GLUCOSIDASE ,CHITIN SYNTHASES ,GENE ,MESH: Fungal Proteins ,MESH: Aspergillus fumigatus ,MESH: Gene Expression Regulation, Fungal ,MESH: Hydrolysis ,Protein Binding ,CAZy ,MESH: Gene Expression ,Hypha ,MESH : Candida albicans ,Glycoside Hydrolases ,Molecular Sequence Data ,Hyphae ,MESH: Glycoproteins ,Biology ,Microbiology ,Cell wall ,Fungal Proteins ,03 medical and health sciences ,MESH : Hydrolysis ,MESH: Hyphae ,MESH: Spores, Fungal ,MESH : Gene Expression Regulation, Fungal ,MESH: Glycoside Hydrolases ,MESH: Protein Binding ,Amino Acid Sequence ,Molecular Biology ,030304 developmental biology ,MESH : Protein Processing, Post-Translational ,Glycoproteins ,MESH: Molecular Sequence Data ,Sequence Homology, Amino Acid ,030306 microbiology ,MESH: Candida albicans ,MESH : Oligosaccharides ,Cell Biology ,biology.organism_classification ,MESH : Glycoproteins ,[SDV.MP.MYC] Life Sciences [q-bio]/Microbiology and Parasitology/Mycology ,Yeast ,MESH: Morphogenesis ,MESH : Gene Expression ,MESH : Morphogenesis ,MESH : Aspergillus fumigatus ,MESH: Protein Processing, Post-Translational ,MESH : Hyphae ,Carbohydrate-binding Protein ,Protein Processing, Post-Translational ,MESH: Oligosaccharides ,Biogenesis - Abstract
International audience; BACKGROUND:SUN proteins are involved in yeast morphogenesis, but their function is unknown.RESULTS:SUN protein plays a role in the Aspergillus fumigatus morphogenesis. Biochemical properties of recombinant SUN proteins were elucidated.CONCLUSION:Both Candida albicans and Aspergillus fumigatus sun proteins show a β-(1,3)-glucanase activity.SIGNIFICANCE:The mode of action of SUN proteins on β-(1,3)-glucan is unique, new, and original. In yeasts, the family of SUN proteins has been involved in cell wall biogenesis. Here, we report the characterization of SUN proteins in a filamentous fungus, Aspergillus fumigatus. The function of the two A. fumigatus SUN genes was investigated by combining reverse genetics and biochemistry. During conidial swelling and mycelial growth, the expression of AfSUN1 was strongly induced, whereas the expression of AfSUN2 was not detectable. Deletion of AfSUN1 negatively affected hyphal growth and conidiation. A closer examination of the morphological defects revealed swollen hyphae, leaky tips, intrahyphal growth, and double cell wall, suggesting that, like in yeast, AfSun1p is associated with cell wall biogenesis. In contrast to AfSUN1, deletion of AfSUN2 either in the parental strain or in the AfSUN1 single mutant strain did not affect colony and hyphal morphology. Biochemical characterization of the recombinant AfSun1p and Candida albicans Sun41p showed that both proteins had a unique hydrolysis pattern: acting on β-(1,3)-oligomers from dimer up to insoluble β-(1,3)-glucan. Referring to the CAZy database, it is clear that fungal SUN proteins represent a new family of glucan hydrolases (GH132) and play an important morphogenetic role in fungal cell wall biogenesis and septation.
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- 2013
47. Productive Infection of Human Skeletal Muscle Cells by Pandemic and Seasonal Influenza A(H1N1) Viruses
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Sandie Munier, Marie-Christine Prévost, Marion Desdouits, Patricia Jeannin, Pierre-Emmanuel Ceccaldi, Sylvie van der Werf, Nadia Naffakh, Gillian Butler-Browne, Antoine Gessain, Simona Ozden, Epidémiologie et Physiopathologie des Virus Oncogènes (EPVO (UMR_3569 / U-Pasteur_3)), Institut Pasteur [Paris] (IP)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Génétique Moléculaire des Virus à ARN - Molecular Genetics of RNA Viruses (GMV-ARN (UMR_3569 / U-Pasteur_2)), Microscopie Ultrastructurale (Plate-forme), Institut Pasteur [Paris] (IP)-Centre National de la Recherche Scientifique (CNRS), Institut de Myologie, Université Pierre et Marie Curie - Paris 6 (UPMC)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Association française contre les myopathies (AFM-Téléthon)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), HAL UPMC, Gestionnaire, Institut Pasteur [Paris]-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut Pasteur [Paris]-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Association française contre les myopathies (AFM-Téléthon)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Pierre et Marie Curie - Paris 6 (UPMC)
- Subjects
Science ,Muscle Fibers, Skeletal ,Receptors, Cell Surface ,Biology ,Virus Replication ,medicine.disease_cause ,Myoblasts ,03 medical and health sciences ,Influenza A Virus, H1N1 Subtype ,0302 clinical medicine ,[SDV.MHEP.MI]Life Sciences [q-bio]/Human health and pathology/Infectious diseases ,medicine ,Influenza A virus ,Humans ,Myocyte ,030212 general & internal medicine ,Muscle, Skeletal ,Myopathy ,Pandemics ,Cell Proliferation ,Cytopathic effect ,[SDV.MP.VIR] Life Sciences [q-bio]/Microbiology and Parasitology/Virology ,Multidisciplinary ,Cell Death ,Myogenesis ,Skeletal muscle ,Cell Differentiation ,medicine.disease ,Virology ,3. Good health ,medicine.anatomical_structure ,Viral replication ,[SDV.MP.VIR]Life Sciences [q-bio]/Microbiology and Parasitology/Virology ,[SDV.MHEP.MI] Life Sciences [q-bio]/Human health and pathology/Infectious diseases ,Medicine ,Seasons ,medicine.symptom ,Rhabdomyolysis ,030217 neurology & neurosurgery ,Research Article - Abstract
International audience; Besides the classical respiratory and systemic symptoms, unusual complications of influenza A infection in humans involve the skeletal muscles. Numerous cases of acute myopathy and/or rhabdomyolysis have been reported, particularly following the outbreak of pandemic influenza A(H1N1) in 2009. The pathogenesis of these influenza-associated myopathies (IAM) remains unkown, although the direct infection of muscle cells is suspected. Here, we studied the susceptibility of cultured human primary muscle cells to a 2009 pandemic and a 2008 seasonal influenza A(H1N1) isolate. Using cells from different donors, we found that differentiated muscle cells (i. e. myotubes) were highly susceptible to infection by both influenza A(H1N1) isolates, whereas undifferentiated cells (i. e. myoblasts) were partially resistant. The receptors for influenza viruses, α2-6 and α2-3 linked sialic acids, were detected on the surface of myotubes and myoblasts. Time line of viral nucleoprotein (NP) expression and nuclear export showed that the first steps of the viral replication cycle could take place in muscle cells. Infected myotubes and myoblasts exhibited budding virions and nuclear inclusions as observed by transmission electron microscopy and correlative light and electron microscopy. Myotubes, but not myoblasts, yielded infectious virus progeny that could further infect naive muscle cells after proteolytic treatment. Infection led to a cytopathic effect with the lysis of muscle cells, as characterized by the release of lactate dehydrogenase. The secretion of proinflammatory cytokines by muscle cells was not affected following infection. Our results are compatible with the hypothesis of a direct muscle infection causing rhabdomyolysis in IAM patients.
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- 2013
48. A novel murine model of rhinoscleroma identifies Mikulicz cells, the disease signature, as IL-10 dependent derivatives of inflammatory monocytes
- Author
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Régis Tournebize, Solenne Taront, Marie-Christine Prévost, Ana Cumano, Michel Huerre, Ana S. Almeida, Cindy Fevre, Sylvain Brisse, Philippe J. Sansonetti, Aurelie Kieusseian, Thierry Pedron, Vougny, Marie-Christine, Génotypage des Pathogènes et Santé Publique (Plate-forme) (PF8), Institut Pasteur [Paris] (IP), Pathogénie Microbienne Moléculaire, Institut Pasteur [Paris] (IP)-Institut National de la Santé et de la Recherche Médicale (INSERM), Histotechnologie et Pathologie, Microscopie Ultrastructurale (Plate-forme), Institut Pasteur [Paris] (IP)-Centre National de la Recherche Scientifique (CNRS), Lymphopoïèse, Développement des Lymphocytes, Collège de France - Chaire Microbiologie et Maladies infectieuses, Collège de France (CdF (institution)), Institut Pasteur [Paris], Institut Pasteur [Paris]-Institut National de la Santé et de la Recherche Médicale (INSERM), Institut Pasteur [Paris]-Centre National de la Recherche Scientifique (CNRS), and Chaire Microbiologie et Maladies infectieuses
- Subjects
Male ,[SDV.IMM] Life Sciences [q-bio]/Immunology ,Klebsiella pneumoniae ,Disease ,Biology ,Monocytes ,Microbiology ,03 medical and health sciences ,Mice ,0302 clinical medicine ,Klebsiella ,medicine ,Animals ,Humans ,Research Articles ,030304 developmental biology ,Rhinoscleroma ,0303 health sciences ,Mice, Inbred BALB C ,inflammatory monocytes ,medicine.disease ,biology.organism_classification ,Pathophysiology ,3. Good health ,Interleukin-10 ,rhinoscleroma ,Mikulicz cell ,Interleukin 10 ,Disease Models, Animal ,medicine.anatomical_structure ,Murine model ,Granuloma ,Immunology ,IL-10 ,Molecular Medicine ,[SDV.IMM]Life Sciences [q-bio]/Immunology ,Bone marrow ,030215 immunology ,Foam Cells - Abstract
International audience; Rhinoscleroma is a human specific chronic disease characterized by the formation of granuloma in the airways, caused by the bacterium Klebsiella pneumoniae subspecies rhinoscleromatis, a species very closely related to K. pneumoniae subspecies pneumoniae. It is characterized by the appearance of specific foamy macrophages called Mikulicz cells. However, very little is known about the pathophysiological processes underlying rhinoscleroma. Herein, we characterized a murine model recapitulating the formation of Mikulicz cells in lungs and identified them as atypical inflammatory monocytes specifically recruited from the bone marrow upon K. rhinoscleromatis infection in a CCR2-independent manner. While K. pneumoniae and K. rhinoscleromatis infections induced a classical inflammatory reaction, K. rhinoscleromatis infection was characterized by a strong production of IL-10 concomitant to the appearance of Mikulicz cells. Strikingly, in the absence of IL-10, very few Mikulicz cells were observed, confirming a crucial role of IL-10 in the establishment of a proper environment leading to the maturation of these atypical monocytes. This is the first characterization of the environment leading to Mikulicz cells maturation and their identification as inflammatory monocytes.
- Published
- 2013
49. The secreted Ipa complex of Shigella flexneri promotes entry into mammalian cells
- Author
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Philippe J. Sansonetti, Marie-Christine Prévost, Pierre Gounon, Christoph Dehio, and Robert Ménard
- Subjects
Latex ,Apoptosis ,Biology ,medicine.disease_cause ,Epithelium ,Shigella flexneri ,Microbiology ,Bacterial Proteins ,Antigen ,medicine ,Extracellular ,Animals ,Humans ,Shigella ,Pathogen ,Actin ,Mammals ,Latex beads ,Antigens, Bacterial ,Multidisciplinary ,Cell Membrane ,biology.organism_classification ,Actins ,Microspheres ,Cell biology ,Microscopy, Electron ,Secretory protein ,Research Article ,HeLa Cells - Abstract
The bacterial pathogen Shigella flexneri causes bacillary dysentery in humans by invading coloncytes. Upon contact with epithelial cells, S. flexneri elicits localized plasma membrane projections sustained by long actin filaments which engulf the microorganism. The products necessary for Shigella entry include three secretory proteins: IpaB, IpaC, and IpaD. Extracellular IpaB and IpaC associate in a soluble complex, the Ipa complex. We have immunopurified this Ipa complex on latex beads and found that they were efficiently internalized into HeLa cells. Like S. flexneri entry, uptake of the beads bearing the Ipa complex was associated with membrane projections and polymerization of actin at the site of cell-bead interaction and was dependent on small Rho GTPases. These results indicate that a secreted factor can promote S. flexneri entry into epithelial cells.
- Published
- 1996
50. Anti-Helicobacter pylori activities of natural isopentenyloxycinnamyl derivatives from Boronia pinnata
- Author
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Valérie Michel, Marie-Christine Prévost, Cécile Ribeiro da Silva, Francesco Epifano, Eliette Touati, Salvatore Genovese, Pathogenèse de Helicobacter, Institut Pasteur [Paris]-Centre National de la Recherche Scientifique (CNRS), Dipartimento di Scienze del Farmaco, Università degli studi 'G. d'Annunzio' Chieti-Pescara [Chieti-Pescara] (Ud'A), Microscopie Ultrastructurale (Plate-forme), This work was funded by the OdysseyRe Company. C. Ribeiro da Silva received a fellowship from the Erasmus program for training students from Escola Superior de Biotecnologia, Catholic University of Porto (Portugal) under the EC’s Leonardo program., and Institut Pasteur [Paris] (IP)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Male ,Plant Science ,MESH: Helicobacter pylori/growth & development ,Bacterial growth ,Mice ,MESH: Anti-Bacterial Agents/pharmacology ,Drug Discovery ,MESH: Animals ,MESH: Microbial Sensitivity Tests ,0303 health sciences ,biology ,Chemistry ,MESH: Helicobacter Infections/drug therapy ,Stomach ,General Medicine ,Plant secondary metabolites ,Boronia pinnata ,3. Good health ,Anti-Bacterial Agents ,MESH: Helicobacter pylori/ultrastructure ,medicine.anatomical_structure ,Oxyprenylated derivatives ,MESH: Stomach/microbiology ,MESH: Microscopy, Electron, Scanning ,Microbial Sensitivity Tests ,Helicobacter pylori infection ,Mouse model ,Microbiology ,Helicobacter Infections ,MESH: Cinnamates/pharmacology ,03 medical and health sciences ,MESH: Mice, Inbred C57BL ,In vivo ,Gastric mucosa ,medicine ,MESH: Cinnamates/isolation & purification ,Animals ,MESH: Mice ,Rutaceae ,MESH: Helicobacter Infections/microbiology ,030304 developmental biology ,Pharmacology ,MESH: Rutaceae/chemistry ,Helicobacter pylori ,MESH: Anti-Bacterial Agents/isolation & purification ,030306 microbiology ,biology.organism_classification ,[SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology ,MESH: Male ,In vitro ,Mice, Inbred C57BL ,Complementary and alternative medicine ,Cinnamates ,Anti-bacterial compounds ,MESH: Helicobacter pylori/drug effects ,[SDV.SP.PHARMA]Life Sciences [q-bio]/Pharmaceutical sciences/Pharmacology ,Microscopy, Electron, Scanning ,Bacterial cellular morphologies - Abstract
International audience; In this study we investigated the anti-Helicobacter pylori activity of four isopentenyloxycinnamyl derivatives from the Australian shrub Boronia pinnata Sm. (Rutaceae), structurally related to boropinic acid: (E)-3-(4-(3-methylbut-2-enyloxy)-3,5-dimethoxyphenyl)acrylaldehyde (1), boropinol C (2), boropinal (3) and boropinol A (4). In vitro growth of H. pylori strains 26695 and B128 was analyzed in liquid culture with increasing doses of these compounds. Bacterial morphology was visualized by scanning electron microscopy. The in vivo effects of the two most efficient molecules that reduced bacterial growth in vitro, compounds 3 and 4, were investigated on H. pylori gastric colonization in the mouse model. The presence of these compounds in the bacterial cultures led to alterations of bacterial surface and flagella. In vivo, both compounds 3 and 4 at 250 microM reduced significantly the ability of H pylori to colonize the gastric mucosa of mice, compared with untreated ones. These data indicate that these natural isopentenyloxycinnamyl derivatives related to boropinic acid can be considered as novel antibacterial agents with anti-H. pylori activity.
- Published
- 2012
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