160 results on '"Jacotot, E."'
Search Results
2. CD26 as a Positive Regulator of HIV Envelope-Glycoprotein Induced Apoptosis in CD4+ T Cells
- Author
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Jacotot, E., Callebaut, C., Blanco, J., Rivière, Y., Krust, B., Hovanessian, A. G., Ansorge, Siegfried, editor, and Langner, Jürgen, editor
- Published
- 1997
- Full Text
- View/download PDF
3. Upstream control of apoptosis by caspase-2 in serum-deprived primary neurons
- Author
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Chauvier, D., Lecoeur, H., Langonné, A., Borgne-Sanchez, A., Mariani, J., Martinou, J.-C., Rebouillat, D., and Jacotot, E.
- Published
- 2005
- Full Text
- View/download PDF
4. Dynamic analysis of apoptosis in primary cortical neurons by fixed- and real-time cytofluorometry
- Author
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Lecoeur, H., Chauvier, D., Langonné, A., Rebouillat, D., Brugg, B., Mariani, J., Edelman, L., and Jacotot, E.
- Published
- 2004
- Full Text
- View/download PDF
5. Effect of a preparation of Saccharomyces cerevisiae on microbial profiles and fermentation patterns in the large intestine of horses fed a high fiber or a high starch diet
- Author
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Medina, B., Girard, I.D., Jacotot, E., and Julliand, V.
- Subjects
Horses ,High-fiber diet ,Starch -- Physiological aspects ,Brewer's yeast -- Physiological aspects ,Zoology and wildlife conservation - Abstract
Eight horses were allotted into pairs consisting of one cecum- and right ventral colon-fistulated animal and one cecum-fistulated animal. They were fed daily at the same level of intake either a high-fiber (HF) or a high-starch (HS) diet without or with 10 g of a Saccharomyces cerevisiae preparation, in a 4 x 4 Latin square design. The HS diet provided a starch overload (i.e., 3.4 g starch*[kg.sup.-1] BW*[meal.sup.-1] while maintaining a high amount of fiber intake (i.e., dietary NDF/ starch ratio was 1.0). A 21-d period of adaptation to the treatments occurred before cecal and colonic contents were withdrawn 4 h after the morning meal to count total anaerobic, cellulolytic, and lactic acid-utilizing bacteria, lactobacilli, and streptococci. Lactic acid, volatile fatty acids, ammonia concentrations, and pH were measured on cecal and colonic fluid samples collected hourly during the first 12-h postfeeding. When the HS diet was fed, the concentration of total anaerobic and lactic acid-utilizing bacteria increased (P < 0.001), whereas that of cellulolytic bacteria decreased (P < 0.05) in the cecum. The concentration of lactobacilli and streptococci increased (P < 0.001) in the cecal and colonic contents. These alterations of the microbial profiles were associated with decreases (P < 0.001) of pH, (acetate + butyrate)/propionate ratio and with an increase (P < 0.001) of lactic acid concentration. Supplementing the S. cerevisiae preparation increased (P < 0.01) the concentration of viable yeast cells, averaging 4.3 x [10.sup.6] and 4.5 x [10.sup.4] cfu/mL in the cecal and colonic contents, respectively. Yeast supplementation had almost no effect on microbial counts in the cecum and colon. The supplementation of S. cerevisiae appeared to modify (P < 0.05) pH, concentrations of lactic acid and ammonia, molar percentages of acetate and butyrate with the HS diet and [(acetate + butyrate)/propionate] ratio when the HF diet was fed. The effects of the S. cerevisiae preparation were greater in the cecum than in the colon, which coincided with the abundance of yeast cells. When the digestion of starch in the small intestine was saturated, the effect of the addition of a S. cerevisiae preparation appeared to limit the extent of undesirable changes in the intestinal ecosystem of the horse. Key Words: Cellulolytic Microorganisms, Horses, Large Intestine Fermentation, Saccharomyces cerevisiae, Starch Digestion
- Published
- 2002
6. P571Ryanodine receptor leak Q: 1 mediated by caspase-8 activation leads to left ventricular injury after myocardial ischemia-reperfusion
- Author
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Fauconnier, J., Meli, A.C., Thireau, J., Roberge, S., Lompre, A.M., Jacotot, E., Marks, A.M., and Lacampagne, A.
- Published
- 2012
7. Combined use of radioimagers and radioactive 3′OH DNA nick end labelling to quantify apoptosis in cell lines and tissue sections: applications to virus-induced apoptosis
- Author
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Jacotot, E., Cardona, A., Rebouillat, D., Terradillos, O., Marianneau, P., Thoulouze, M.-I., Lafon, M., Deubel, V., and Edelman, L.
- Published
- 1999
- Full Text
- View/download PDF
8. Palmitate induces apoptosis via a direct effect on mitochondria
- Author
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de Pablo, M. A., Susin, S. A., Jacotot, E., Larochette, N., Costantini, P., Ravagnan, L., Zamzami, N., and Kroemer, G.
- Published
- 1999
- Full Text
- View/download PDF
9. HIV-1 envelope glycoproteins-mediated apoptosis is regulated by CD4 dependent and independent mechanisms
- Author
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Jacotot, E., Krust, B., Callebaut, C., Laurent-Crawford, A. G., Blanco, J., and Hovanessian, A.
- Published
- 1997
- Full Text
- View/download PDF
10. Feeding and microbial disorders in horses: 1-effects of an abrupt incorporation of two levels of barley in a hay diet on microbial profile and activities
- Author
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de Fombelle, A., Julliand, V., Drogoul, C., and Jacotot, E.
- Published
- 2001
- Full Text
- View/download PDF
11. Feeding and microbial disorders in horses: Part 3—Effects of three hay:grain ratios on microbial profile and activities
- Author
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Julliand, V., de Fombelle, A., Drogoul, C., and Jacotot, E.
- Published
- 2001
- Full Text
- View/download PDF
12. Adenosine deaminase binding to human CD26 is inhibited by HIV-1 envelope glycoprotein gp120 and viral particles
- Author
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Valenzuela, A., Julià Blanco, Callebaut, C., Jacotot, E., Lluis, C., Hovanessian, A. G., and Franco, R.
- Subjects
B-Lymphocytes ,Adenosine Deaminase ,Dipeptidyl Peptidase 4 ,T-Lymphocytes ,Molecular Sequence Data ,Immunology ,Virion ,Humans ,Immunology and Allergy ,Amino Acid Sequence ,HIV Envelope Protein gp120 ,Cell Line ,Protein Binding - Abstract
CD26, known to be the adenosine deaminase (ADA)-binding protein, has been implicated in HIV infection. Several studies have revealed a correlation between depletion of CD4+/CD26+ T lymphocytes, increased serum levels of ADA, and the evolution of AIDS in infected individuals. We show that in human B and T cell lines, irrespective of CD4 expression, 125I-labeled ADA binding to CD26 is inhibited by recombinant soluble HIV-1 envelope glycoprotein gp120 and by HIV-1 infectious particles. Accordingly, an anti-CD4 mAb, which inhibits the binding of gp120 to CD4 and blocks viral infection, did not affect inhibition of 125I-labeled ADA binding to CD26 by HIV particles. On the other hand, mAbs directed against the V3 loop and the C-terminal region of gp120 abolished completely the inhibitory effect. Overlapping synthetic peptides covering the entire gp120 sequence were tested to map the region in gp120 responsible for ADA binding inhibition. Only peptides in the C3 region significantly inhibited the binding of ADA to CD26. These results provide indirect evidence for the interaction of gp120 with CD26 and indicate that a specific function of gp120 is the inhibition of ADA binding to CD26 in both CD4+ and CD4- cells. Because ADA deficiency leads to severe combined immunodefiency syndrome, it remains possible that HIV particle-mediated blockade of ADA-CD26 interaction may have significant consequences in the pathogenesis of AIDS.
- Published
- 1997
13. Peptidotargeting of the mitochondrial permeability transition pore complex for therapeutic Apoptosis induction
- Author
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Deniaud, Aurelien, Hoebeke, J., Briand, Jp, Jacotot, E., Brenner, Catherine, Begue, Angelique, Laboratoire de génétique et biologie cellulaire (LGBC), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)
- Subjects
[SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biochemistry [q-bio.BM] ,[SDV.BBM.BC] Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biochemistry [q-bio.BM] ,[SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biomolecules [q-bio.BM] - Published
- 2006
14. Chemosensitization by knock-down of adenine nucleotide translocase-2
- Author
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Le Bras, M., Borgne-Sanchez, A., Touat, Zahia, Sharaf El Dein, Ossama, Deniaud, Aurelien, Maillier, Evelyne, Lecellier, Geal, Rebouillat, D., Lemaire, Christophe, Kroemer, G., Jacotot, E., Brenner, Catherine, Laboratoire de génétique et biologie cellulaire (LGBC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), and Begue, Angelique
- Subjects
[SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biochemistry [q-bio.BM] ,[SDV.BBM.BC] Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biochemistry [q-bio.BM] ,[SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biomolecules [q-bio.BM] - Published
- 2006
15. Peptido-targeting of the mitochondrial transition pore complex for therapeutic apoptosis induction
- Author
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A. Hoebeke J. Briand J-P. Muller S. Jacotot E. & Brenner C., Deniaud and Wencker, Suzanne
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[SDV.BC] Life Sciences [q-bio]/Cellular Biology ,ComputingMilieux_MISCELLANEOUS - Published
- 2006
16. The mitochondrion as a target of anti-cancer chemotherapy
- Author
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Costantini, Paola, Jacotot, E., Decaudin, D., and Kroemer, G.
- Published
- 2000
17. Apoptosis and cell cycle: distinct checkpoints with overlapping upstream control
- Author
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Jacotot, E., Ferri, Kf, Kroemer, G., and Deleage, Gilbert
- Subjects
[SDV.BBM] Life Sciences [q-bio]/Biochemistry, Molecular Biology - Abstract
The question as to whether apoptosis (programmed cell death) is controlled by one or few checkpoints is still unresolved. A growing body of evidence suggests that (one of) the decisive event(s) of cell death consists in the permeabilization of mitochondrial membranes. Indeed, multiple pro-apopotic signal transduction pathways converge on the proteins of the Bcl-2/Bax family which, in concert with the so-called permeability transition pore complex (PTPC), regulate mitochondrial membrane barrier function. Mitochondrial permeabilization causes the release of soluble intermembrane proteins, some of which are involved in the activation of apoptotic proteases and nucleases. Thus, the putative checkpoint determining the death/life decision is clearly different from the known checkpoints of cell cycle progression. Prominent oncogenes (e.g., c-Myc, Ras, Raf, Bcl-2) and tumor suppressor genes (e.g., p53, Bax) have been shown to modulate apoptosis via a direct or indirect effect on mitochondrial membranes. All these oncoproteins and tumor suppressor proteins may simultaneously influence the cell cycle and the propensity to undergo apoptosis. Several cell cycle regulatory proteins (e.g., cyclins, cdk, etc.) can induce or inhibit apoptosis via yet unknown pathways.The question as to whether apoptosis (programmed cell death) is controlled by one or few checkpoints is still unresolved. A growing body of evidence suggests that (one of) the decisive event(s) of cell death consists in the permeabilization of mitochondrial membranes. Indeed, multiple pro-apopotic signal transduction pathways converge on the proteins of the Bcl-2/Bax family which, in concert with the so-called permeability transition pore complex (PTPC), regulate mitochondrial membrane barrier function. Mitochondrial permeabilization causes the release of soluble intermembrane proteins, some of which are involved in the activation of apoptotic proteases and nucleases. Thus, the putative checkpoint determining the death/life decision is clearly different from the known checkpoints of cell cycle progression. Prominent oncogenes (e.g., c-Myc, Ras, Raf, Bcl-2) and tumor suppressor genes (e.g., p53, Bax) have been shown to modulate apoptosis via a direct or indirect effect on mitochondrial membranes. All these oncoproteins and tumor suppressor proteins may simultaneously influence the cell cycle and the propensity to undergo apoptosis. Several cell cycle regulatory proteins (e.g., cyclins, cdk, etc.) can induce or inhibit apoptosis via yet unknown pathways.
- Published
- 2000
18. HIV-1 envelope gp120 and viral particles block adenosine deaminase binding to human CD26
- Author
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Valenzuela A, Blanco J, Callebaut C, Jacotot E, Lluis C, Ag, Hovanessian, and Rafael Franco
- Subjects
Adenosine Deaminase ,Dipeptidyl Peptidase 4 ,T-Lymphocytes ,HIV-1 ,Virion ,Humans ,HIV Infections ,HIV Envelope Protein gp120 ,Virus Replication - Abstract
CD26, known to be the adenosine deaminase (ADA) binding protein, has been implicated in HIV infection. In human B and T cell lines we show that, irrespective of CD4 expression, 125I-labeled ADA binding to CD26 is inhibited by recombinant soluble HIV-1 envelope glycoprotein gp120 and by HIV-1 infectious particles. Overlapping synthetic peptides covering the entire gp120 sequence were tested to map the region in gp120 responsible for ADA binding inhibition. Only peptides in the C3 region significantly inhibited the binding of ADA to CD26. These results indicate that a specific function of gp120 is the inhibition of ADA binding to CD26 in both CD4+ and CD4- cells. Since the interaction ecto-ADA/CD26 is required for the activation of T cells, it remains possible that HIV particle-mediated blockade of ecto-ADA/CD26 interaction may have significant consequences in the pathogenesis of AIDS disease.
- Published
- 1997
19. Targeted Vpr-derived peptides reach mitochondria to induce apoptosis of αVβ3-expressing endothelial cells.
- Author
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Borgne-Sanchez, A., Dupont, S., Langonné, A., Baux, L., Lecoeur, H., Chauvier, D., Lassalle, M., Déas, O., Brière, J.-J., Brabant, M., Roux, P., Péchoux, C., Briand, J.-P., Hoebeke, J., Deniaud, A., Brenner, C., Rustin, P., Edelman, L., Rebouillat, D., and Jacotot, E.
- Subjects
PEPTIDES ,MITOCHONDRIA ,APOPTOSIS ,ADENINE nucleotides ,CYTOCHROME c ,MITOCHONDRIAL membranes - Abstract
The HIV-1 encoded apoptogenic protein Vpr induces mitochondrial membrane permeabilization (MMP) via interactions with the voltage-dependent anion channel (VDAC) and the adenine nucleotide translocator (ANT). We have designed a peptide, TEAM-VP, composed of two functional domains, one a tumor blood vessel RGD-like ‘homing’ motif and the other an MMP-inducing sequence derived from Vpr. When added to isolated mitochondria, TEAM-VP interacts with ANT and VDAC, reduces oxygen consumption and overcomes Bcl-2 protection to cause inner and outer MMP. TEAM-VP specifically recognizes cell-surface expressed α
V β3 integrins, internalizes, temporarily localizes to lysosomes and progressively co-distributes with the mitochondrial compartment with no sign of lysosomal membrane permeabilization. Finally TEAM-VP reaches mitochondria of angiogenic endothelial cells to induce mitochondrial fission, dissipation of the mitochondrial transmembrane potential (ΔΨm ), cytochrome c release and apoptosis hallmarks. Hence, this chimeric peptide constitutes the first example of a virus-derived mitochondriotoxic compound as a candidate to kill selectively tumor neo-endothelia.Cell Death and Differentiation (2007) 14, 422–435. doi:10.1038/sj.cdd.4402018; published online 4 August 2006 [ABSTRACT FROM AUTHOR]- Published
- 2007
- Full Text
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20. Broad-spectrum caspase inhibitors: from myth to reality?
- Author
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Chauvier, D., Ankri, S., Charriaut-Marlangue, C., Casimir, R., and Jacotot, E.
- Subjects
LETTERS to the editor ,CELL death - Abstract
A letter to the editor on the use of broad-spectrum caspase inhibitors in elucidating apoptotic cell death pathways is presented.
- Published
- 2007
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- View/download PDF
21. Characterization of the microbial and biochemical profile of the different segments of the digestive tract in horses given two distinct diets.
- Author
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Fombelle, A. de, Varloud, M., Goachet, A.-G., Jacotot, E., Philippeau, C., Drogoul, C., and Julliand, V.
- Subjects
GASTROINTESTINAL system ,MICROORGANISMS ,HORSES ,ANIMAL nutrition ,COLON (Anatomy) - Abstract
A first group of three horses was given diet 1 (D1) allowing 1180 g per 100 kg body weight (BW) of a pelleted food rich in fibre (P1) and 556 g per 100 kg BW of straw during a 20-day period to allow for adaptation. A second group of four horses were given diet 2 (D2) allowing 1180 g per 100 kg BW of a pelleted food rich in cereals (P2) and 1000 g per 100 kg BW of meadow hay during the same period. Digesta was collected from the stomach, duodenum, jejunum, ileum, caecum, right ventral colon, left ventral colon, left dorsal colon, right dorsal colon, and small colon, and faeces were collected under general anaesthesia 2.5 h after the ingestion of the morning pelleted meal. The concentration of total anaerobic, cellulolytic and lactic acid-utilizing bacteria, lactobacilli and streptococci were determined in all these segments except for the duodenum, left ventral colon, right dorsal colon and small colon. D-/L-lactic acid, volatile fatty acids and pH were measured in all anatomic segments of the digestive tract (from stomach to small colon). The caecal concentration of total anaerobic bacteria was the lowest (7.9 x 10[sup7] colony-forming units (c. f. u. ) per ml), whereas that of the stomach was the highest (1.4 x 10[sup9] c. f. u. per ml) (P < 0.001). Cellulolytic bacteria did not exceed 3.0 x 10² c. f. u. per ml in the ante-caecal segments whereas in the hindgut the average concentration was 5.3 x 10[sup5] c. f. u. per ml (P < 0.001). Likewise, VFA concentrations were also greater in the large intestine (on average, 96.3 mmol/l v. 8.8 mmol/l in the ante-caecal segments) (P <... [ABSTRACT FROM AUTHOR]
- Published
- 2003
22. Permeabilization of the mitochondrial inner membrane during apoptosis: impact of the adenine nucleotide translocator.
- Author
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Vieira, H L A, Haouzi, D, El Hamel, C, Jacotot, E, Belzacq, A-S, Brenner, C, and Kroemer, G
- Subjects
MITOCHONDRIAL membranes ,APOPTOSIS ,CELL death - Abstract
Mitochondrial membrane permeabilization can be a rate limiting step of apoptotic as well as necrotic cell death. Permeabilization of the outer mitochondrial membrane (OM) and/or inner membrane (IM) is, at least in part, mediated by the permeability transition pore complex (PTPC). The PTPC is formed in the IM/OM contact site and contains the two most abundant IM and OM proteins, adenine nucleotide translocator (ANT, in the IM) and voltage-dependent anion channel (VDAC, in the OM), the matrix protein cyclophilin D, which can interact with ANT, as well as apoptosis-regulatory proteins from the Bax/Bcl-2 family. Here we discuss that ANT has two opposite functions. On the one hand, ANT is a vital, specific antiporter which accounts for the exchange of ATP and ADP on IM. On the other hand, ANT can form a non-specific pore, as this has been shown by electrophysiological characterization of purified ANT reconstituted into synthetic lipid bilayers or by measuring the permeabilization of proteoliposomes containing ANT. Pore formation by ANT is induced by a variety of different agents (e.g. Ca[sup 2+], atractyloside, thiol oxidation, the pro-apoptotic HIV-1 protein Vpr, etc.) and is enhanced by Bax and inhibited by Bcl-2, as well as by ADP. In isolated mitochondria, pore formation by ANT leads to an increase in IM permeability to solutes up to 1500 Da, swelling of the mitochondrial matrix, and OM permeabilization, presumably due to physical rupture of OM. Although alternative mechanisms of mitochondrial membrane permeabilization may exist, ANT emerges as a major player in the regulation of cell death. [ABSTRACT FROM AUTHOR]
- Published
- 2000
- Full Text
- View/download PDF
23. Mitochondrion as a novel target of anticancer chemotherapy.
- Author
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Costantini, Paola, Jacotot, Etienne, Costantini, P, Jacotot, E, Decaudin, D, and Kroemer, G
- Subjects
MITOCHONDRIA ,CANCER chemotherapy ,APOPTOSIS ,MOLECULES - Abstract
Mitochondrial membrane permeabilization is a critical event in the process leading to physiologic or chemotherapy-induced apoptosis (programmed cell death). This permeabilization event is, at least in part, under the control of the permeability transition pore complex (PTPC). Oncoproteins from the Bcl-2 family and tumor suppressor proteins from the Bax family interact with PTPC to inhibit or facilitate membrane permeabilization, respectively. Conventional chemotherapeutic agents elicit mitochondrial permeabilization in an indirect fashion by induction of endogenous effectors that are involved in the physiologic control of apoptosis. However, an increasing number of experimental anticancer drugs, including lonidamine, arsenite, betulinic acid, CD437, and several amphipathic cationic alpha-helical peptides, act directly on mitochondrial membranes and/or on the PTPC. Such agents may induce apoptosis in circumstances in which conventional drugs fail to act because endogenous apoptosis induction pathways, such as those involving p53, death receptors, or apical caspase activation, are disrupted. However, stabilization of the mitochondrial membrane by antiapoptotic Bcl-2-like proteins reduces the cytotoxic potential of most of these drugs. Targeting of specific PTPC components may overcome this Bcl-2-mediated apoptosis inhibition. One strategy involves cross-linking of critical redox-sensitive thiol groups within the PTPC; another involves the use of ligands to the mitochondrial benzodiazepine receptor. Thus, the design of mitochondrion-targeted cytotoxic drugs may constitute a novel strategy for overcoming apoptosis resistance. [ABSTRACT FROM AUTHOR]
- Published
- 2000
- Full Text
- View/download PDF
24. 581 DISCUSSION Use of functional human cancer cell line mitochondria to explore the mechanisms of ABT-737-induced mitochondrial membrane permeabilization
- Author
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Buron, N., Porceddu, M., Rustin, P., Jacotot, E., and Borgne-Sanchez, A.
- Published
- 2010
- Full Text
- View/download PDF
25. Effect of a preparation of Saccharomyces cerevisiaeon microbial profiles and fermentation patterns in the large intestine of horses fed a high fiber or a high starch diet1
- Author
-
Medina, B., Girard, I. D., Jacotot, E., and Julliand, V.
- Abstract
Eight horses were allotted into pairs consisting of one cecum- and right ventral colon-fistulated animal and one cecum-fistulated animal. They were fed daily at the same level of intake either a high-fiber (HF) or a high-starch (HS) diet without or with 10 g of a Saccharomyces cerevisiaepreparation, in a 4 × 4 Latin square design. The HS diet provided a starch overload (i.e., 3.4 g starch•kg−1BW•meal−1) while maintaining a high amount of fiber intake (i.e., dietary NDF/starch ratio was 1.0). A 21-d period of adaptation to the treatments occurred before cecal and colonic contents were withdrawn 4 h after the morning meal to count total anaerobic, cellulolytic, and lactic acid-utilizing bacteria, lactobacilli, and streptococci. Lactic acid, volatile fatty acids, ammonia concentrations, and pH were measured on cecal and colonic fluid samples collected hourly during the first 12-h postfeeding. When the HS diet was fed, the concentration of total anaerobic and lactic acid-utilizing bacteria increased (P< 0.001), whereas that of cellulolytic bacteria decreased (P< 0.05) in the cecum. The concentration of lactobacilli and streptococci increased (P< 0.001) in the cecal and colonic contents. These alterations of the microbial profiles were associated with decreases (P< 0.001) of pH, (acetate + butyrate)/propionate ratio and with an increase (P< 0.001) of lactic acid concentration. Supplementing the S. cerevisiaepreparation increased (P< 0.01) the concentration of viable yeast cells, averaging 4.3 × 106and 4.5 × 104cfu/mL in the cecal and colonic contents, respectively. Yeast supplementation had almost no effect on microbial counts in the cecum and colon. The supplementation of S. cerevisiaeappeared to modify (P< 0.05) pH, concentrations of lactic acid and ammonia, molar percentages of acetate and butyrate with the HS diet and [(acetate + butyrate)/propionate] ratio when the HF diet was fed. The effects of the S. cerevisiaepreparation were greater in the cecum than in the colon, which coincided with the abundance of yeast cells. When the digestion of starch in the small intestine was saturated, the effect of the addition of a S. cerevisiaepreparation appeared to limit the extent of undesirable changes in the intestinal ecosystem of the horse.
- Published
- 2002
- Full Text
- View/download PDF
26. Specific and Irreversible Cyclopeptide Inhibitors of Dipeptidyl Peptidase IV Activity of the T-Cell Activation Antigen CD26
- Author
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Nguyen, C., Blanco, J., Mazaleyrat, J.-P., Krust, B., Callebaut, C., Jacotot, E., Hovanessian, A. G., and Wakselman, M.
- Abstract
The dipeptidyl peptidase IV (DPP IV) activity of CD26 is characterized by its post-proline-cleaving capacity that plays an important but not yet understood role in biological processes. Here we describe a new family of specific and irreversible inhibitors of this enzyme. Taking into account the substrate specificity of DPP IV for P
2 -P1 ><-P1 cleavage, we have designed and synthesized cyclopeptides c[(αH2 N+)-Lys-Pro-Aba-(6-CH2 -S+R2 )-Glyn ] 2TFA- (Aba = 3-aminobenzoic acid, R = alkyl) possessing a proline at the P 1 position and a lysine in the P2 position, which allows the closing of the cycle on its side chain. These molecules show a free N-terminus, necessary for binding to the CD26 catalytic site, and a latent quinoniminium methide electrophile, responsible for inactivation. Treatment of c[αZ-Lys-Pro-Aba-(6-CH2 -OC6 H5 )-Glyn ], obtained by peptide synthesis in solution, with R 2 S/TFA simutaneously cleaved the Z protecting group and the phenyl ether function and led to a series of cyclopeptide sulfonium salts. These cyclopeptides inhibited rapidly and irreversibly the DPP IV activity of CD26, with IC50 values in the nanomolar range. Further studies were carried out to investigate the effect of the modification of the ring size (n = 2 or 4) and the nature of the sulfur substituents (R = Me, Bu, Oct). Cycle enlargement improved the inhibitory activity of the methylsulfonio cyclopeptide, whereas the increase of the alkyl chain length on the sulfur atom had no apparent effect. Other aminopeptidases were not inhibited, and a much weaker activity was observed on a novel isoform of DPP IV referred to as DPP IV-β. Thus, this new family of irreversible inhibitors of DPP IV is highly specific to the peptidase activity of CD26.- Published
- 1998
27. Pseudopeptide TASP inhibitors of HIV entry bind specifically to a 95-kDa cell surface protein.
- Author
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Callebaut, C, Jacotot, E, Krust, B, Guichard, G, Blanco, J, Valenzuela, A, Svab, J, Muller, S, Briand, J P, and Hovanessian, A G
- Abstract
The template assembled synthetic peptide constructs (TASP), pentavalently presenting the tripeptide KPR or RPK, are potent and specific inhibitors of human immunodeficiency virus (HIV) infection by preventing viral entry into permissive cells. Here the 5[KPsi(CH2N)PR]-TASP construct, Psi(CH2N) for reduced peptide bond, was used in studies to demonstrate its specific binding to a 95-kDa cell surface protein ligand. Compared to its nonreduced 5[KPR]-TASP counterpart, the pseudopeptide 5[KPsi(CH2N)PR]-TASP manifested higher affinity to bind to its cell surface ligand, increased activity to inhibit HIV infection, and resistance to degradation when incubated in serum from an HIV-1 seropositive individual. In ligand blotting experiments, the biotin-labeled 5[KPsi(CH2N)PR]-TASP identified a single 95-kDa protein in crude cell extracts. This 95-kDa protein (p95) is expressed on the cell surface since surface iodination of cells resulted in its labeling, and moreover, following incubation of cells with the biotin-labeled 5[KPsi(CH2N)PR]-TASP, the p95.TASP complex was recovered by affinity chromatography using avidin-agarose. All anti-HIV TASP constructs but not their control derivatives affected the binding of biotin-labeled 5[KPsi(CH2N)PR]-TASP to p95, thus emphasizing the specific nature of this binding. Since 5[KPsi(CH2N)PR]-TASP does not interact with HIV-envelope glycoproteins, our results suggest that TASP inhibitors mediate directly or indirectly a block in HIV-mediated membrane fusion process by binding to the cell surface expressed p95.
- Published
- 1997
28. Identification of V3 loop-binding proteins as potential receptors implicated in the binding of HIV particles to CD4(+) cells.
- Author
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Callebaut, C, Blanco, J, Benkirane, N, Krust, B, Jacotot, E, Guichard, G, Seddiki, N, Svab, J, Dam, E, Muller, S, Briand, J P, and Hovanessian, A G
- Abstract
The binding of human immunodeficiency virus (HIV) type 1 particles to CD4(+) cells could be blocked either by antibodies against the V3 loop domain of the viral external envelope glycoprotein gp120, or by the V3 loop mimicking pseudopeptide 5[Kpsi(CH2N)PR]-TASP, which forms a stable complex with a cell-surface-expressed 95-kDa protein. Here, by using an affinity matrix containing 5[Kpsi(CH2N)PR]-TASP and cytoplasmic extracts from human CEM cells, we purified three V3 loop-binding proteins of 95, 40, and 30 kDa, which after microsequencing were revealed to be as nucleolin, putative HLA class II-associated protein (PHAP) II, and PHAP I, respectively. The 95-kDa cell-surface protein was also isolated and found to be nucleolin. We show that recombinant preparations of gp120 bind the purified preparations containing the V3 loop-binding proteins with a high affinity, comparable to the binding of gp120 to soluble CD4. Such binding is inhibited either by 5[Kpsi(CH2N)PR]-TASP or antibodies against the V3 loop. Moreover, these purified preparations inhibit HIV entry into CD4(+) cells as efficiently as soluble CD4. Taken together, our results suggest that nucleolin, PHAP II, and PHAP I appear to be functional as potential receptors in the HIV binding process by virtue of their capacity to interact with the V3 loop of gp120.
- Published
- 1998
29. Apoptosis and karyogamy in syncytia induced by the HIV-1-envelope glycoprotein complex.
- Author
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Ferri, K.F., Jacotot, E., Geuskens, M., and Kroemer, G.
- Subjects
- *
GLYCOPROTEIN hormones , *TUMOR necrosis factors , *HIV antibodies , *CD4 antigen , *RECEPTOR antibodies , *IMMUNOGLOBULINS , *APOPTOSIS - Abstract
Examines the capacity of HIV-1-envelope glycoprotein complex to induce apoptosis and karyogamy in syncytia. Mechanisms accounting for HIV-1-induced lypmhodepletion; Capacity of the envelope glycoprotein complex expressed on HIV-1 infected cells to interact with CD4 and a suitable coreceptor; Functional relationship between syncitium formation, karyogamy and apoptosis.
- Published
- 2000
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30. Palmitate induces apoptosis via a direct effect on mitochondria
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Pablo, M. A., Susin, S. A., Jacotot, E., Larochette, N., Costantini, P., Ravagnan, L., Zamzami, N., and Guido Kroemer
31. Apoptosis induction by the photosensitizer verteporfin: identification of mitochondrial adenine nucleotide translocator as a critical target
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Belzacq, A. S., Jacotot, E., Vieira, H. L., Mistro, D., Granville, D. J., Xie, Z., Reed, J. C., Guido Kroemer, and Brenner, C.
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Male ,Cell Membrane Permeability ,Photosensitizing Agents ,Porphyrins ,Mitochondrial Permeability Transition Pore ,Membrane Proteins ,Verteporfin ,Antineoplastic Agents ,Apoptosis ,Transfection ,Mitochondrial Membrane Transport Proteins ,Ion Channels ,Membrane Potentials ,Mitochondria ,Rats ,Jurkat Cells ,Mice ,Proto-Oncogene Proteins c-bcl-2 ,Liposomes ,Animals ,Humans ,Rats, Wistar ,Mitochondrial ADP, ATP Translocases - Abstract
We report that the photosensitizer verteporfin kills lymphoma cells by an apoptotic process involving a dissipation of the mitochondrial inner transmembrane potential (deltapsim). Light-activated verteporfin-induced apoptosis was abolished by transfection with Bcl-2, a procedure reported to inhibit the mitochondrial permeability transition pore complex (PTPC). Verteporfin triggered the deltapsim loss in isolated mitochondria in vitro, and this effect was suppressed by bongrekic acid and cyclosporin A. Verteporfin plus light also permeabilized proteoliposomes containing the semipurified PTPC or the purified PTPC component adenine nucleotide translocator (ANT), yet had no effect on protein-free control liposomes. Verteporfin phototoxicity on ANT proteoliposomes was mediated by reactive oxygen species and was prevented by recombinant Bcl-2 or the adenine nucleotides ATP and ADP. In conclusion, verteporfin belongs to a class of clinically used chemotherapeutic agents acting on PTPC and ANT.
32. Apoptosis control in syncytia induced by the HIV type 1-envelope glycoprotein complex: role of mitochondria and caspases
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Ferri, K. F., Jacotot, E., Blanco, J., Este, J. A., Zamzami, N., Susin, S. A., Xie, Z., Brothers, G., Reed, J. C., Penninger, J. M., Guido Kroemer, and Deleage, Gilbert
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viruses ,[SDV.BBM] Life Sciences [q-bio]/Biochemistry, Molecular Biology ,cardiovascular diseases ,biological phenomena, cell phenomena, and immunity - Abstract
Syncytia arising from the fusion of cells expressing a lymphotropic HIV type 1-encoded envelope glycoprotein complex (Env) with cells expressing the CD4/CXC chemokine receptor 4 complex spontaneously undergo cell death. Here we show that this process is accompanied by caspase activation and signs of mitochondrial membrane permeabilization (MMP), including the release of intermembrane proteins such as cytochrome c (Cyt-c) and apoptosis-inducing factor (AIF) from mitochondria. In Env-induced syncytia, caspase inhibition did not suppress AIF- and Cyt-c translocation, yet it prevented all signs of nuclear apoptosis. Translocation of Bax to mitochondria led to MMP, which was inhibited by microinjected Bcl-2 protein or bcl-2 transfection. Bcl-2 also prevented the subsequent nuclear chromatin condensation and DNA fragmentation. The release of AIF occurred before that of Cyt-c and before caspase activation. Microinjection of AIF into syncytia sufficed to trigger rapid, caspase-independent Cyt-c release. Neutralization of endogenous AIF by injection of an antibody prevented all signs of spontaneous apoptosis occurring in syncytia, including the Cyt-c release and nuclear apoptosis. In contrast, Cyt-c neutralization only prevented nuclear apoptosis, and did not affect AIF release. Our results establish that the following molecular sequence governs apoptosis of Env-induced syncytia: Bax-mediated/Bcl-2-inhibited MMP --> AIF release --> Cyt-c release --> caspase activation --> nuclear apoptosis.Syncytia arising from the fusion of cells expressing a lymphotropic HIV type 1-encoded envelope glycoprotein complex (Env) with cells expressing the CD4/CXC chemokine receptor 4 complex spontaneously undergo cell death. Here we show that this process is accompanied by caspase activation and signs of mitochondrial membrane permeabilization (MMP), including the release of intermembrane proteins such as cytochrome c (Cyt-c) and apoptosis-inducing factor (AIF) from mitochondria. In Env-induced syncytia, caspase inhibition did not suppress AIF- and Cyt-c translocation, yet it prevented all signs of nuclear apoptosis. Translocation of Bax to mitochondria led to MMP, which was inhibited by microinjected Bcl-2 protein or bcl-2 transfection. Bcl-2 also prevented the subsequent nuclear chromatin condensation and DNA fragmentation. The release of AIF occurred before that of Cyt-c and before caspase activation. Microinjection of AIF into syncytia sufficed to trigger rapid, caspase-independent Cyt-c release. Neutralization of endogenous AIF by injection of an antibody prevented all signs of spontaneous apoptosis occurring in syncytia, including the Cyt-c release and nuclear apoptosis. In contrast, Cyt-c neutralization only prevented nuclear apoptosis, and did not affect AIF release. Our results establish that the following molecular sequence governs apoptosis of Env-induced syncytia: Bax-mediated/Bcl-2-inhibited MMP --> AIF release --> Cyt-c release --> caspase activation --> nuclear apoptosis.
33. Ryanodine receptor leak Q:1 mediated by caspase-8 activation leads to left ventricular injury after myocardial ischemia-reperfusion
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Fauconnier, J., Albano Meli, Thireau, J., Roberge, S., Lompre, A. M., Jacotot, E., Marks, A. M., and Lacampagne, A.
34. CD26 antigen and HIV fusion?
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Broder, C. C., Nussbaum, O., Gutheil, W. G., Bachovchin, W. W., Berger, E. A., Patience, C., Aine McKnight, Clapham, P. R., Boyd, M. T., Weiss, R. A., Schulz, T. F., Camerini, D., Planelles, V., Chen, I. S. Y., Alizon, M., Dragic, T., Callebaut, C., Jacotot, E., Krust, B., and Hovanessian, A. G.
35. HIV-1 envelope gp120 and viral particles block adenosine deaminase binding to human CD26
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Valenzuela, A., Julià Blanco, Callebaut, C., Jacotot, E., Lluis, C., Hovanessian, A. G., and Franco, R.
36. Mitochondrial control of cell death induced by HIV-1-encoded proteins
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Ferri, K. F., Jacotot, E., Julià Blanco, Esté, J. A., and Kroemer, G.
37. On the induction of apoptosis by the HIV envelope glycoprotein complex
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Jacotot, E., Callebaut, C., and Hovanessian, A.G.
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HIV (Viruses) -- Physiological aspects ,Cell death -- Physiological aspects ,Glycoproteins -- Physiological aspects - Abstract
AUTHORS: E. Jacotot, C. Callebaut and A.G. Hovanessian. Institut Pasteur, Unite de Virologie et Immunologie Cellulaire, Paris, France. According to an abstract submitted by the authors to the Keystone Symposia [...]
- Published
- 1994
38. T-cell activation antigen, CD26, as a cofactor for entry of HIV in CD4+ cells
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Callebaut, C., Krust, B., Jacotot, E., and Hovanessian, A.G.
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HIV (Viruses) ,T cells -- Physiological aspects - Abstract
SOURCE: Science, December 24, 1993;262(5142):2045-2050. According to the authors' abstract of an article published in Science, "The CD4 molecule is essential for binding HIV particles, but is not sufficient for [...]
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- 1994
39. Selective loss of the CD4 +/CD26 + T-cell subset during HIV infection
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Gougeon, M.-L., Lecoeur, H., Callebaut, C., Jacotot, E., Dulioust, A., Roué, R., Montagnier, L., and Hovanessian, A.G.
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- 1996
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40. IMPACT OF THE CASPASE2 INHIBITOR TRP601 ON APOPTOTIC SIGNALING IN THE DEVELOPING BRAIN DURING HYPEROXIA
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Sifringer, M., Boos, V., Börner, C., von Haefen, C., Endesfelder, S., Bendix, I., Jacotot, E., Keller, M., and FelderhoffMueser, U.
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- 2010
41. 111 Impact of the Caspase-2 Inhibitor Trp601 on Apoptotic Signaling in the Developing Brain During Hyperoxia
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Sifringer, M, Boos, V, Börner, C, Von Haefen, C, Endesfelder, S, Bendix, I, Jacotot, E, Keller, M, and Felderhoff-Mueser, U
- Abstract
Background and aims: Experimental studies show that oxygen, which is widely used in neonatal medicine for resuscitation and treatment of pulmonary hypertension, triggers a disruption of the maintenance of intracellular redox homeostasis. This disturbance can lead to oxidative stress and furthermore to neuronal apoptosis in the developing brain. The role of caspase-2 in apoptosis is poorly defined. Many in vitro studies of caspase-2 knockdown in cultured cells have implicated this caspase in cell death in response to different signaling pathways. To elucidate mechanisms of the caspase-2 inhibitor TRP601 and its mode of functioning in the developing brain in the context of hyperoxia, we investigated its impact on the levels of APAF-1, AIF, cytochrome c, caspase-9 and -3.Methods: Six-day old rats were exposed together with their mothers to 80% oxygen in the presence or absence of the caspase-2 inhibitor TRP601 (1 mg/kg) and were sacrificed after 12 or 24 hrs of hyperoxia following treatment. Dissected brains were either examined histologically to visualize degenerating cells or were subjected to protein studies.Results: Oxygen exposure triggered cell death at 12 to 24 hrs, which was attenuated by TRP601 treatment. Our protein studies demonstrated an upregulation of APAF-1, AIF, cytochrome c, caspase-9 and -3 in the cytosolic fraction of brain homogenates after hyperoxia, which reached control levels following TRP601 treatment.Conclusion: These findings suggest a protective role for the caspase-2 inhibitor TRP601 in the prevention of neonatal oxygen-induced apoptotic brain damage.Supported by the European Commission (Sixth Framework Program, contract no LSHM- CT-2006-036534).
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- 2010
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42. HIV-1 Tat protein directly induces mitochondrial membrane permeabilization and inactivates cytochrome c oxidase
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Olivier Chaloin, Etienne Daniel Francois Jacotot, Pierre Rustin, Mathieu Porceddu, Alain Langonne, Aurélien Deniaud, Magali Brabant, Catherine Brenner, Hervé Lecoeur, S. Muller, J-J Brière, J. P. Briand, Christine Péchoux, Nelly Buron, Dominique Rebouillat, Ralph El-Khoury, A. Borgne-Sanchez, Immunophysiologie et Parasitisme Intracellulaire, Institut Pasteur [Paris] (IP), Theraptosis S.A., Theraptosis SA, Mitologics SAS, Hôpital Robert Debré, Immunologie et chimie thérapeutiques (ICT), Cancéropôle du Grand Est-Centre National de la Recherche Scientifique (CNRS), Physiopathologie, conséquences fonctionnelles et neuroprotection des atteintes du cerveau en développement, Université Paris Diderot - Paris 7 (UPD7)-IFR2-Institut National de la Santé et de la Recherche Médicale (INSERM), Physiopathologie et neuroprotection des atteintes du cerveau en développement, Université Paris Diderot - Paris 7 (UPD7)-Institut National de la Santé et de la Recherche Médicale (INSERM), Unité de recherche génomique et physiologie de la lactation (GPL), Institut National de la Recherche Agronomique (INRA), Laboratoire de génétique et biologie cellulaire (LGBC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Signalisation et physiopathologie cardiaque, Université Paris-Sud - Paris 11 (UP11)-IFR141-Institut National de la Santé et de la Recherche Médicale (INSERM), INSERM UMR676, Université Paris Diderot - Paris 7 (UPD7)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Laboratoire de Biochimie, Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Hôpital Robert Debré-Université Paris Diderot - Paris 7 (UPD7)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Hôpital Robert Debré, Department of Reproductive Biology, Imperial College London, French Ministry of Research, ANVAR, Sidaction, AFM, Ammi, CNRS, Inserm, CRITT Ile de France, Institut Pasteur [Paris], CNRS FRE 2445, Centre National de la Recherche Scientifique (CNRS), Génomique et Physiologie de la Lactation (GPL), Assistance publique - Hôpitaux de Paris (AP-HP) (APHP)-Hôpital Robert Debré-Université Paris Diderot - Paris 7 (UPD7)-Assistance publique - Hôpitaux de Paris (AP-HP) (APHP)-Hôpital Robert Debré, Pansiot, Sylvie, Laboratoire de génétique et biologie cellulaire, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), and Jacotot, E
- Subjects
Cancer Research ,Cytochrome ,Virologie ,[SDV.BC.BC]Life Sciences [q-bio]/Cellular Biology/Subcellular Processes [q-bio.SC] ,Mitochondrion ,4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid ,medicine.disease_cause ,MESH: 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid ,Oxidative Phosphorylation ,chemistry.chemical_compound ,Mice ,0302 clinical medicine ,membrane mitochondriale ,MESH: Mitochondrial Membranes ,MESH: Membrane Potential, Mitochondrial ,cytochrome c oxidase ,MESH: Animals ,Membrane Potential, Mitochondrial ,0303 health sciences ,Mice, Inbred BALB C ,cytochrome c oxydase ,biology ,Cytochrome c ,microscopie électronique ,Brain ,Cytochromes c ,MESH: Cytochromes c ,3. Good health ,Mitochondria ,protéine virale ,HIV-1 ,Tat ,mitochondria ,Liver ,Proto-Oncogene Proteins c-bcl-2 ,mitochondrie ,DIDS ,MESH: Permeability ,Mitochondrial Membranes ,Original Article ,tat Gene Products, Human Immunodeficiency Virus ,MESH: Myocardium ,Viral protein ,MESH: Mitochondria ,Immunology ,MESH: Mice, Inbred BALB C ,polarographie ,potentiel transmembranaire ,Oxidative phosphorylation ,spectrophotométrie ,spectrofluorométrie ,Permeability ,Electron Transport Complex IV ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,MESH: Brain ,MESH: Electron Transport Complex IV ,MESH: Oxidative Phosphorylation ,Virology ,[SDV.BC.BC] Life Sciences [q-bio]/Cellular Biology/Subcellular Processes [q-bio.SC] ,medicine ,Cytochrome c oxidase ,Animals ,Humans ,MESH: Mice ,technique elisa ,030304 developmental biology ,MESH: tat Gene Products, Human Immunodeficiency Virus ,MESH: Humans ,Ion Transport ,synthèse de protéine ,perméabilité cellulaire ,Myocardium ,Cell Biology ,Molecular biology ,MESH: Ion Transport ,chemistry ,MESH: Proto-Oncogene Proteins c-bcl-2 ,biology.protein ,virus de l'immunodéficience humaine ,030217 neurology & neurosurgery ,MESH: Liver - Abstract
International audience; The Trans-activator protein (Tat) of human immunodeficiency virus (HIV) is a pleiotropic protein involved in different aspects of AIDS pathogenesis. As a number of viral proteins Tat is suspected to disturb mitochondrial function. We prepared pure synthetic full-length Tat by native chemical ligation (NCL), and Tat peptides, to evaluate their direct effects on isolated mitochondria. Submicromolar doses of synthetic Tat cause a rapid dissipation of the mitochondrial transmembrane potential (ΔΨ(m)) as well as cytochrome c release in mitochondria isolated from mouse liver, heart, and brain. Accordingly, Tat decreases substrate oxidation by mitochondria isolated from these tissues, with oxygen uptake being initially restored by adding cytochrome c. The anion-channel inhibitor 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) protects isolated mitochondria against Tat-induced mitochondrial membrane permeabilization (MMP), whereas ruthenium red, a ryanodine receptor blocker, does not. Pharmacologic inhibitors of the permeability transition pore, Bax/Bak inhibitors, and recombinant Bcl-2 and Bcl-XL proteins do not reduce Tat-induced MMP. We finally observed that Tat inhibits cytochrome c oxidase (COX) activity in disrupted mitochondria isolated from liver, heart, and brain of both mouse and human samples, making it the first described viral protein to be a potential COX inhibitor.
- Published
- 2012
43. Fibrobacter sp. HC4, a newly isolated strain, demonstrates a high cellulolytic activity as revealed by enzymatic measurements and in vitro assay.
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Froidurot A, Jacotot E, Julliand S, Grimm P, and Julliand V
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- Animals, Horses, Cellulase metabolism, Cellulase genetics, Cecum microbiology, Bacterial Proteins genetics, Bacterial Proteins metabolism, Gastrointestinal Microbiome, Glycoside Hydrolases metabolism, Glycoside Hydrolases genetics, Cellobiose metabolism, Cellulose metabolism, Fibrobacter genetics, Fibrobacter enzymology, Fibrobacter isolation & purification, Fibrobacter metabolism, Feces microbiology
- Abstract
Despite their low quantity and abundance, the cellulolytic bacteria that inhabit the equine large intestine are vital to their host, as they enable the crucial use of forage-based diets. Fibrobacter succinogenes is one of the most important intestinal cellulolytic bacteria. In this study, Fibrobacter sp. HC4, one cellulolytic strain newly isolated from the horse cecum, was characterized for its ability to utilize plant cell wall fibers. Fibrobacter sp. HC4 consumed only cellulose, cellobiose, and glucose and produced succinate and acetate in equal amounts. Among genes coding for CAZymes, 26% of the detected glycoside hydrolases (GHs) were involved in cellulolysis. These cellulases belong to the GH5, GH8, GH9, GH44, GH45, and GH51 families. Both carboxymethyl cellulase and xylanase activities of Fibrobacter sp. HC4 were detected using the Congo red method and were higher than those of F. succinogenes S85, the type strain. The in vitro addition of Fibrobacter sp. HC4 to a fecal microbial ecosystem of horses with large intestinal acidosis significantly enhanced fibrolytic activity as measured by the increase in gas and volatile fatty acids production during the first 48 h. According to this, the pH decreased and the disappearance of dry matter increased at a faster rate with Fibrobacter sp. HC4. Our data suggest a high specialization of the new strain in cellulose degradation. Such a strain could be of interest for future exploitation of its probiotic potential, which needs to be further determined by in vivo studies.IMPORTANCECellulose is the most abundant of plant cell wall fiber and can only be degraded by the large intestine microbiota, resulting in the production of volatile fatty acids that are essential for the host nutrition and health. Consequently, cellulolytic bacteria are of major importance to herbivores. However, these bacteria are challenged by various factors, such as high starch diets, which acidify the ecosystem and reduce their numbers and activity. This can lead to an imbalance in the gut microbiota and digestive problems such as colic, a major cause of mortality in horses. In this work, we characterized a newly isolated cellulolytic strain, Fibrobacter sp. HC4, from the equine intestinal microbiota. Due to its high cellulolytic capacity, reintroduction of this strain into an equine fecal ecosystem stimulates hay fermentation in vitro . Isolating and describing cellulolytic bacteria is a prerequisite for using them as probiotics to restore intestinal balance., Competing Interests: The authors declare no conflict of interest.
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- 2024
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44. The transplantation of the gut microbiome of fat-1 mice protects against colonic mucus layer disruption and endoplasmic reticulum stress induced by high fat diet.
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Bourragat A, Escoula Q, Bellenger S, Zemb O, Beaumont M, Chaumonnot K, Farine JP, Jacotot E, Bonnotte A, Avoscan L, Lherminier J, Luo K, Narce M, and Bellenger J
- Subjects
- Animals, Mice, Male, Obesity metabolism, Obesity microbiology, Mucus metabolism, Mice, Inbred C57BL, Mucins metabolism, Goblet Cells metabolism, Fecal Microbiota Transplantation, Endoplasmic Reticulum Stress, Diet, High-Fat adverse effects, Gastrointestinal Microbiome, Fatty Acids, Omega-3 metabolism, Colon microbiology, Colon metabolism, Intestinal Mucosa metabolism, Intestinal Mucosa microbiology, Mice, Transgenic
- Abstract
High-fat diets alter gut barrier integrity, leading to endotoxemia by impacting epithelial functions and inducing endoplasmic reticulum (ER) stress in intestinal secretory goblet cells. Indeed, ER stress, which is an important contributor to many chronic diseases such as obesity and obesity-related disorders, leads to altered synthesis and secretion of mucins that form the protective mucus barrier. In the present study, we investigated the relative contribution of omega-3 polyunsaturated fatty acid (PUFAs)-modified microbiota to alleviating alterations in intestinal mucus layer thickness and preserving gut barrier integrity. Male fat-1 transgenic mice (exhibiting endogenous omega-3 PUFAs tissue enrichment) and wild-type (WT) littermates were fed either an obesogenic high-fat diet (HFD) or a control diet. Unlike WT mice, HFD-fed fat-1 mice were protected against mucus layer alterations as well as an ER stress-mediated decrease in mucin expression. Moreover, cecal microbiota transferred from fat-1 to WT mice prevented changes in the colonic mucus layer mainly through colonic ER stress downregulation. These findings highlight a novel feature of the preventive effects of omega-3 fatty acids against intestinal permeability in obesity-related conditions.
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- 2024
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45. Whole-Genome Sequencing and Annotation of Fibrobacter succinogenes HC4, Isolated from the Horse Cecum.
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Froidurot A, Jacotot E, and Julliand V
- Abstract
Fibrobacter succinogenes is a major cellulolytic bacterial species living in the large intestines of herbivores. This study reports the genome sequencing, assembly, and annotation of F. succinogenes HC4 (DSM 33656), a strain isolated from horse cecal contents. The genome comprised a total of 3.74 Mbp, with a G+C content of 48.96%.
- Published
- 2022
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46. Biomarkers for monitoring the equine large intestinal inflammatory response to stress-induced dysbiosis and probiotic supplementation.
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Collinet A, Grimm P, Jacotot E, and Julliand V
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- Animals, Anti-Bacterial Agents therapeutic use, Bacteria, Biomarkers, Dietary Supplements, Dysbiosis veterinary, Fatty Acids, Horses, Immunoglobulin A, Secretory, Immunoglobulins, Intestine, Large, Lipopolysaccharides, Mammals, Starch, Sulfadiazine, Trimethoprim, Horse Diseases, Probiotics
- Abstract
Large intestine barrier disturbances can have serious consequences for the health of horses. The loss of mucosal integrity that leads to increased intestinal permeability may result from a local inflammatory immune response following alterations of the microbiota, known as dysbiosis. Therefore, our research aimed to identify noninvasive biomarkers for studying the intestinal permeability and the local inflammatory immune response in horses. Regarding the biomarkers used in other mammalian species, we measured the concentrations of lipopolysaccharides (LPS), reflected by 3-OH C14, C16, and C18 fatty acids, in blood, and fecal secretory immunoglobulin-A (SIgA). These biomarkers were evaluated in two trials including 9 and 12 healthy horses, which developed large intestinal dysbiosis experimentally induced by 5 d of antibiotic administration (trimethoprim sulfadiazine [TMS]) or 5 d of abrupt introduction of high starch levels (barley) into the diet. Horses were either control or supplemented with Lactobacillus acidophilus, Ligilactobacillus salivarius, and Bifidobacterium lactis. Correlations were performed between biomarkers and fecal bacterial diversity, composition, and function. No significant interaction between day and supplementation, or supplementation effect were observed for each biomarker. However, with the dietary stressor, a significant increase in blood concentrations of 3-OH C16 (P = 0.0125) and C14 (P = 0.0252) fatty acids was measured 2 d after the cessation of barley administration. Furthermore, with the antibiotic stressor, blood levels of 3-OH C16 progressively increased (P = 0.0114) from the first day to 2 d after the end of TMS administration. No significant day effect was observed for fecal SIgA concentrations for both stressors. These results indicate that both antibiotic- and diet-induced dysbiosis resulted in a local translocation of LPS 2 d after the cessation of the stressor treatments, suggesting an impairment of intestinal permeability, without detectable local inflammation. Blood LPS and fecal SIgA concentrations were significantly correlated with several bacterial variations in the large intestine, which are features of antibiotic- and diet-induced dysbiosis. These findings support the hypothesis that a relationship exists between dysbiosis and the loss of mucosal integrity in the large intestine of horses., (© The Author(s) 2022. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
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- 2022
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47. Nicotinamide riboside, a form of vitamin B 3 , protects against excitotoxicity-induced axonal degeneration.
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Vaur P, Brugg B, Mericskay M, Li Z, Schmidt MS, Vivien D, Orset C, Jacotot E, Brenner C, and Duplus E
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- Animals, Cell Death drug effects, Cells, Cultured, Male, Mice, Mice, Inbred C57BL, Mice, Knockout, N-Methylaspartate pharmacology, Neurons drug effects, Neurons metabolism, Neuroprotective Agents pharmacology, Niacinamide pharmacology, Pyridinium Compounds, Real-Time Polymerase Chain Reaction, Axons drug effects, Axons metabolism, Niacinamide analogs & derivatives
- Abstract
NAD
+ depletion is a common phenomenon in neurodegenerative pathologies. Excitotoxicity occurs in multiple neurologic disorders and NAD+ was shown to prevent neuronal degeneration in this process through mechanisms that remained to be determined. The activity of nicotinamide riboside (NR) in neuroprotective models and the recent description of extracellular conversion of NAD+ to NR prompted us to probe the effects of NAD+ and NR in protection against excitotoxicity. Here, we show that intracortical administration of NR but not NAD+ reduces brain damage induced by NMDA injection. Using cortical neurons, we found that provision of extracellular NR delays NMDA-induced axonal degeneration (AxD) much more strongly than extracellular NAD+ Moreover, the stronger effect of NR compared to NAD+ depends of axonal stress since in AxD induced by pharmacological inhibition of nicotinamide salvage, both NAD+ and NR prevent neuronal death and AxD in a manner that depends on internalization of NR. Taken together, our findings demonstrate that NR is a better neuroprotective agent than NAD+ in excitotoxicity-induced AxD and that axonal protection involves defending intracellular NAD+ homeostasis.-Vaur, P., Brugg, B., Mericskay, M., Li, Z., Schmidt, M. S., Vivien, D., Orset, C., Jacotot, E., Brenner, C., Duplus, E. Nicotinamide riboside, a form of vitamin B3 , protects against excitotoxicity-induced axonal degeneration., (© FASEB.)- Published
- 2017
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48. β-amyloid induces a dying-back process and remote trans-synaptic alterations in a microfluidic-based reconstructed neuronal network.
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Deleglise B, Magnifico S, Duplus E, Vaur P, Soubeyre V, Belle M, Vignes M, Viovy JL, Jacotot E, Peyrin JM, and Brugg B
- Subjects
- Animals, Axons drug effects, Axons metabolism, Axons pathology, Cerebral Cortex drug effects, Cerebral Cortex metabolism, Mice, Microfluidic Analytical Techniques methods, Nerve Net drug effects, Nerve Net metabolism, Neurons drug effects, Neurons metabolism, Neurons pathology, Phosphorylation, Primary Cell Culture methods, Synapses drug effects, Synapses metabolism, tau Proteins metabolism, Amyloid beta-Peptides toxicity, Cerebral Cortex pathology, Nerve Net pathology, Synapses pathology
- Abstract
Introduction: Recent histopathological studies have shown that neurodegenerative processes in Alzheimer's and Parkinson's Disease develop along neuronal networks and that hallmarks could propagate trans-synaptically through neuronal pathways. The underlying molecular mechanisms are still unknown, and investigations have been impeded by the complexity of brain connectivity and the need for experimental models allowing a fine manipulation of the local microenvironment at the subcellular level., Results: In this study, we have grown primary cortical mouse neurons in microfluidic (μFD) devices to separate soma from axonal projections in fluidically isolated microenvironments, and applied β-amyloid (Aβ) peptides locally to the different cellular compartments. We observed that Aβ application to the somato-dendritic compartment triggers a "dying-back" process, involving caspase and NAD(+) signalling pathways, whereas exposure of the axonal/distal compartment to Aβ deposits did not induce axonal degeneration. In contrast, co-treatment with somatic sub-toxic glutamate and axonal Aβ peptide triggered axonal degeneration. To study the consequences of such subcellular/local Aβ stress at the network level we developed new μFD multi-chamber devices containing funnel-shaped micro-channels which force unidirectional axon growth and used them to recreate in vitro an oriented cortico-hippocampal pathway. Aβ application to the cortical somato-dendritic chamber leads to a rapid cortical pre-synaptic loss. This happens concomitantly with a post-synaptic hippocampal tau-phosphorylation which could be prevented by the NMDA-receptor antagonist, MK-801, before any sign of axonal and somato-dendritic cortical alteration., Conclusion: Thanks to μFD-based reconstructed neuronal networks we evaluated the distant effects of local Aβ stress on neuronal subcompartments and networks. Our data indicates that distant neurotransmission modifications actively take part in the early steps of the abnormal mechanisms leading to pathology progression independently of local Aβ production. This offers new tools to decipher mechanisms underlying Braak's staging. Our data suggests that local Aβ can play a role in remote tauopathy by distant disturbance of neurotransmission, providing a putative mechanism underlying the spatiotemporal appearance of pretangles.
- Published
- 2014
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49. Molecular monitoring of the bacterial community structure in foal feces pre- and post-weaning.
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Faubladier C, Sadet-Bourgeteau S, Philippeau C, Jacotot E, and Julliand V
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- Age Factors, Animals, Animals, Newborn, DNA Fingerprinting, DNA, Ribosomal Spacer genetics, Longitudinal Studies, Bacteria classification, Bacteria genetics, Biota, Feces microbiology, Horses microbiology, Weaning
- Abstract
This study assessed the time-scale variability of bacterial community structure in foal feces from birth to 365 days of age using Automated Ribosomal Intergenic Spacer Analysis (ARISA). Fecal samples were collected from five foals 2 h after birth (meconium) and in the morning at days 1, 2, 5, 10, 30, 60, 120, 179, 183, 194 and 365. The ARISA profiles were compared using an analysis of similarity (ANOSIM). Although both the age effect and the foal effect were highly significant (P < 0.010), the R-ANOSIM value for the foal effect was very low (R-ANOSIM = 0.089), while that of the age effect was much higher (R-ANOSIM = 0.309). Significant age-related changes were detected between days 0 and 2 (R-ANOSIM = 0.500), days 2 and 10 (R-ANOSIM = 0.475) and days 10 and 30 (R-ANOSIM = 0.519). No further shifts between consecutive times of sampling were detected in the bacterial community after day 30 and no changes were observed at weaning (day 180). These results show that the establishment of the intestinal bacterial community in foals is a sequential process, which reaches its climax state at around one month of age. Further studies using new generation sequencing based methods could be conducted to identify which bacterial genera are establishing in foals during the first month of life., (Copyright © 2013 Elsevier Ltd. All rights reserved.)
- Published
- 2014
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50. Characterization of phenotype markers and neuronotoxic potential of polarised primary microglia in vitro.
- Author
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Chhor V, Le Charpentier T, Lebon S, Oré MV, Celador IL, Josserand J, Degos V, Jacotot E, Hagberg H, Sävman K, Mallard C, Gressens P, and Fleiss B
- Subjects
- Animals, Cell Polarity, Cell Survival physiology, Cerebral Cortex cytology, Chemokines metabolism, Cytokines metabolism, Female, Fluorescent Antibody Technique, Gene Expression, Immunohistochemistry, Lipopolysaccharides pharmacology, Male, Mice, Neurons physiology, Phenotype, Primary Cell Culture, RNA biosynthesis, RNA genetics, Real-Time Polymerase Chain Reaction, Toll-Like Receptor 4 metabolism, Microglia pathology
- Abstract
Microglia mediate multiple facets of neuroinflammation, including cytotoxicity, repair, regeneration, and immunosuppression due to their ability to acquire diverse activation states, or phenotypes. Modulation of microglial phenotype is an appealing neurotherapeutic strategy but a comprehensive study of classical and more novel microglial phenotypic markers in vitro is lacking. The aim of this study was to outline the temporal expression of a battery of phenotype markers from polarised microglia to generate an in vitro tool for screening the immunomodulatory potential of novel compounds. We characterised expression of thirty-one macrophage/microglial phenotype markers in primary microglia over time (4, 12, 36, and 72 h), using RT-qPCR or multiplex protein assay. Firstly, we selected Interleukin-4 (IL-4) and lipopolysaccharide (LPS) as the strongest M1-M2 polarising stimuli, from six stimuli tested. At each time point, markers useful to identify that microglia were M1 included iNOS, Cox-2 and IL-6 and a loss of M2a markers. Markers useful for quantifying M2b-immunomodulatory microglia included, increased IL-1RA and SOCS3 and for M2a-repair and regeneration, included increased arginase-1, and a loss of the M1 and M2b markers were discriminatory. Additional markers were regulated at fewer time points, but are still likely important to monitor when assessing the immunomodulatory potential of novel therapies. Further, to facilitate identification of how novel immunomodulatory treatments alter the functional affects of microglia, we characterised how the soluble products from polarised microglia affected the type and rate of neuronal death; M1/2b induced increasing and M2a-induced decreasing neuronal loss. We also assessed any effects of prior activation state, to provide a way to identify how a novel compound may alter phenotype depending on the stage of injury/insult progression. We identified generally that a prior M1/2b reduced the ability of microglia to switch to M2a. Altogether, we have characterised a profile of phenotype markers and a mechanism of assessing functional outcome that we can use as a reference guide for first-line screening of novel immunomodulatory therapies in vitro in the search for viable neuroprotectants., (Copyright © 2013 Elsevier Inc. All rights reserved.)
- Published
- 2013
- Full Text
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