44 results on '"Agresti, Alessandra"'
Search Results
2. Small transcriptional differences among cell clones lead to distinct NF-κB dynamics
- Author
-
Kizilirmak, Cise, Monteleone, Emanuele, García-Manteiga, José Manuel, Brambilla, Francesca, Agresti, Alessandra, Bianchi, Marco E., and Zambrano, Samuel
- Published
- 2023
- Full Text
- View/download PDF
3. First Responders Shape a Prompt and Sharp NF-κB-Mediated Transcriptional Response to TNF-α
- Author
-
Zambrano, Samuel, Loffreda, Alessia, Carelli, Elena, Stefanelli, Giacomo, Colombo, Federica, Bertrand, Edouard, Tacchetti, Carlo, Agresti, Alessandra, Bianchi, Marco E., Molina, Nacho, and Mazza, Davide
- Published
- 2020
- Full Text
- View/download PDF
4. Aging, inflammation and DNA damage in the somatic testicular niche with idiopathic germ cell aplasia
- Author
-
Alfano, Massimo, Tascini, Anna Sofia, Pederzoli, Filippo, Locatelli, Irene, Nebuloni, Manuela, Giannese, Francesca, Garcia-Manteiga, Jose Manuel, Tonon, Giovanni, Amodio, Giada, Gregori, Silvia, Agresti, Alessandra, Montorsi, Francesco, and Salonia, Andrea
- Published
- 2021
- Full Text
- View/download PDF
5. Disulfide HMGB1 derived from platelets coordinates venous thrombosis in mice
- Author
-
Stark, Konstantin, Philippi, Vanessa, Stockhausen, Sven, Busse, Johanna, Antonelli, Antonella, Miller, Meike, Schubert, Irene, Hoseinpour, Parandis, Chandraratne, Sue, von Brühl, Marie-Luise, Gaertner, Florian, Lorenz, Michael, Agresti, Alessandra, Coletti, Raffaele, Antoine, Daniel J., Heermann, Ralf, Jung, Kirsten, Reese, Sven, Laitinen, Iina, Schwaiger, Markus, Walch, Axel, Sperandio, Markus, Nawroth, Peter P., Reinhardt, Christoph, Jäckel, Sven, Bianchi, Marco E., and Massberg, Steffen
- Published
- 2016
- Full Text
- View/download PDF
6. Myelomonocytic cells in giant cell arteritis activate trained immunity programs sustaining inflammation and cytokine production.
- Author
-
Cantoni, Eleonora, Merelli, Ivan, Stefanoni, Davide, Tomelleri, Alessandro, Campochiaro, Corrado, Giordano, Vito, Panigada, Maddalena, Baldissera, Elena M, Pich, Laura Merlo, Natoli, Valentina, Ziogas, Athanasios, Domínguez-Andrés, Jorge, Luca, Giacomo De, Mazza, Davide, Zambrano, Samuel, Gnani, Daniela, Ferrarini, Marina, Ferrero, Elisabetta, Agresti, Alessandra, and Vergani, Barbara
- Subjects
CYTOKINES ,NATURAL immunity ,SEQUENCE analysis ,INFLAMMATION ,CHRONIC diseases ,IMMUNOHISTOCHEMISTRY ,METABOLOMICS ,GIANT cell arteritis ,GENE expression ,GENES ,RESEARCH funding ,MONOCYTES ,VASCULITIS - Abstract
Objective Trained immunity (TI) is a de facto memory program of innate immune cells, characterized by immunometabolic and epigenetic changes sustaining enhanced production of cytokines. TI evolved as a protective mechanism against infections; however, inappropriate activation can cause detrimental inflammation and might be implicated in the pathogenesis of chronic inflammatory diseases. In this study, we investigated the role of TI in the pathogenesis of giant cell arteritis (GCA), a large-vessel vasculitis characterized by aberrant macrophage activation and excess cytokine production. Methods Monocytes from GCA patients and from age- and sex-matched healthy donors were subjected to polyfunctional studies, including cytokine production assays at baseline and following stimulation, intracellular metabolomics, chromatin immunoprecipitation-qPCR, and combined ATAC/RNA sequencing. Immunometabolic activation (i.e. glycolysis) was assessed in inflamed vessels of GCA patients with FDG-PET and immunohistochemistry (IHC), and the role of this pathway in sustaining cytokine production was confirmed with selective pharmacologic inhibition in GCA monocytes. Results GCA monocytes exhibited hallmark molecular features of TI. Specifically, these included enhanced IL-6 production upon stimulation, typical immunometabolic changes (e.g. increased glycolysis and glutaminolysis) and epigenetic changes promoting enhanced transcription of genes governing pro-inflammatory activation. Immunometabolic changes of TI (i.e. glycolysis) were a feature of myelomonocytic cells in GCA lesions and were required for enhanced cytokine production. Conclusions Myelomonocytic cells in GCA activate TI programs sustaining enhanced inflammatory activation with excess cytokine production. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
7. The transcriptional regulator Sin3A balances IL‐17A and Foxp3 expression in primary CD4 T cells.
- Author
-
Perucho, Laura, Icardi, Laura, Di Simone, Elisabetta, Basso, Veronica, Agresti, Alessandra, Vilas Zornoza, Amaia, Lozano, Teresa, Prosper, Felipe, Lasarte, Juan José, and Mondino, Anna
- Abstract
The Sin3 transcriptional regulator homolog A (Sin3A) is the core member of a multiprotein chromatin‐modifying complex. Its inactivation at the CD4/CD8 double‐negative stage halts further thymocyte development. Among various functions, Sin3A regulates STAT3 transcriptional activity, central to the differentiation of Th17 cells active in inflammatory disorders and opportunistic infections. To further investigate the consequences of conditional Sin3A inactivation in more mature precursors and post‐thymic T cell, we have generated CD4‐Cre and CD4‐CreERT2 Sin3AF/F mice. Sin3A inactivation in vivo hinders both thymocyte development and peripheral T‐cell survival. In vitro, in Th17 skewing conditions, Sin3A‐deficient cells proliferate and acquire memory markers and yet fail to properly upregulate Il17a, Il23r, and Il22. Instead, IL‐2+ and FOXP3+ are mostly enriched for, and their inhibition partially rescues IL‐17A+ T cells. Notably, Sin3A deletion also causes an enrichment of genes implicated in the mTORC1 signaling pathway, overt STAT3 activation, and aberrant cytoplasmic RORγt accumulation. Thus, together our data unveil a previously unappreciated role for Sin3A in shaping critical signaling events central to the acquisition of immunoregulatory T‐cell phenotypes. Synopsis: This study identifies a role for the transcriptional regulator Sin3A in shaping Th‐17 differentiation. Inducible Sin3A deletion causes overt STAT3 activation and aberrant cytoplasmic RORγt localization hindering IL‐17A levels in favor of Foxp3 expression.The transcriptional regulator Sin3A contributes to CD4 T‐cell development and differentiation.Sin3A inactivation in mature T cells promotes mTORC1 signaling, STAT3 activation, and aberrant cytoplasmic RORγt accumulation.Sin3A balances IL‐17A, IL‐2, and Foxp3, thereby shaping the immunoregulatory potential of Th17 lymphocytes. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
8. Aspirin’s Active Metabolite Salicylic Acid Targets High Mobility Group Box 1 to Modulate Inflammatory Responses
- Author
-
Choi, Hyong Woo, Tian, Miaoying, Song, Fei, Venereau, Emilie, Preti, Alessandro, Park, Sang-Wook, Hamilton, Keith, Swapna, G. V. T., Manohar, Murli, Moreau, Magali, Agresti, Alessandra, Gorzanelli, Andrea, De Marchis, Francesco, Wang, Huang, Antonyak, Marc, Micikas, Robert J., Gentile, Daniel R., Cerione, Richard A., Schroeder, Frank C., Montelione, Gaetano T., Bianchi, Marco E., and Klessig, Daniel F.
- Published
- 2015
- Full Text
- View/download PDF
9. The combination of marker gene swapping and fluorescence-activated cell sorting improves the efficiency of recombinant modified vaccinia virus Ankara vaccine production for human use
- Author
-
Di Lullo, Giulia, Soprana, Elisa, Panigada, Maddalena, Palini, Alessio, Agresti, Alessandra, Comunian, Claudio, Milani, Adelaide, Capua, Ilaria, Erfle, Volker, and Siccardi, Antonio G.
- Published
- 2010
- Full Text
- View/download PDF
10. c-Rel is a selective activator of a novel IL-4/CD40 responsive element in the human Ig γ4 germline promoter
- Author
-
Agresti, Alessandra and Vercelli, Donata
- Published
- 2002
- Full Text
- View/download PDF
11. Nucleosomes effectively shield DNA from radiation damage in living cells.
- Author
-
Brambilla, Francesca, Garcia-Manteiga, Jose Manuel, Monteleone, Emanuele, Hoelzen, Lena, Zocchi, Angelica, Agresti, Alessandra, and Bianchi, Marco E
- Published
- 2020
- Full Text
- View/download PDF
12. Chromosomal location by in situ hybridization of the human Sau3A family of DNA repeats
- Author
-
Agresti, Alessandra, Rainaldi, G., Lobbiani, Andrea, Magnani, Ivana, Di Lernia, R., Meneveri, Raffaella, Siccardi, A. G., and Ginelli, E.
- Published
- 1987
- Full Text
- View/download PDF
13. LPS-Challenged Macrophages Release Microvesicles Coated With Histones.
- Author
-
Nair, Rohini Ravindran, Mazza, Davide, Brambilla, Francesca, Gorzanelli, Andrea, Agresti, Alessandra, and Bianchi, Marco E.
- Subjects
HISTONES ,CHROMATIN ,NEUTROPHILS - Abstract
Histones are the protein component of nucleosomes, which are the basic packing unit of chromatin. However, histones are also found in the blood, both as components of nucleosomes leaked out from dead cells, or expelled from neutrophils in the active process of NET formation. Circulating histones contribute to inflammation, and to lethality in sepsis, a hyperinflammatory condition, by interacting with specific receptors, notably toll-like receptor 4 (TLR4). Here, we show that histones are also actively released by LPS-activated macrophages in association with extracellular vesicles. Vesicle-associated histones can be recovered from the plasma of mice with sepsis. Actively released histones are on the outer surface of vesicles and can interact with TLR4. Thus, activated macrophages release histones without dying, at the same time, making their DNA more accessible and communicating to other cells that infection is present. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
14. Chromatin conformation regulates the coordination between DNA replication and transcription.
- Author
-
Almeida, Ricardo, Miguel Fernández-Justel, José, Santa-María, Cristina, Cadoret, Jean-Charles, Cano-Aroca, Laura, Lombraña, Rodrigo, Herranz, Gonzalo, Agresti, Alessandra, and Gómez, María
- Abstract
Chromatin is the template for the basic processes of replication and transcription, making the maintenance of chromosomal integrity critical for cell viability. To elucidate how dividing cells respond to alterations in chromatin structure, here we analyse the replication programme of primary cells with altered chromatin configuration caused by the genetic ablation of the HMGB1 gene, or three histone H1 genes. We find that loss of chromatin compaction in H1-depleted cells triggers the accumulation of stalled forks and DNA damage as a consequence of transcription–replication conflicts. In contrast, reductions in nucleosome occupancy due to the lack of HMGB1 cause faster fork progression without impacting the initiation landscape or fork stability. Thus, perturbations in chromatin integrity elicit a range of responses in the dynamics of DNA replication and transcription, with different consequences on replicative stress. These findings have broad implications for our understanding of how defects in chromatin structure contribute to genomic instability. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
15. Single-cell analyses reveal an attenuated NF- κ B response in the Salmonella -infected fibroblast.
- Author
-
Ramos-Marquès, Estel, Zambrano, Samuel, Tiérrez, Alberto, Bianchi, Marco E., Agresti, Alessandra, and García-del Portillo, Francisco
- Subjects
SALMONELLA ,FIBROBLASTS ,PATHOGENIC microorganisms ,SINGLE cell lipids ,COMMUNICABLE disease treatment ,MYCOSES - Abstract
The eukaryotic transcriptional regulator Nuclear Factor kappa B (NF-κB) plays a central role in the defense to pathogens. Despite this, few studies have analyzed NF-κB activity in single cells during infection. Here, we investigated at the single cell level how NF-κB nuclear localization – a proxy for NF-κB activity – oscillates in infected and uninfected fibroblasts co-existing in cultures exposed toSalmonella entericaserovar Typhimurium. Fibroblasts were used due to the capacity ofS. Typhimurium to persist in this cell type. Real-time dynamics of NF-κB was examined in microfluidics, which prevents cytokine accumulation. In this condition, infected (ST+) cells translocate NF-κB to the nucleus at higher rate than the uninfected (ST-) cells. Surprisingly, in non-flow (static) culture conditions, ST- fibroblasts exhibited higher NF-κB nuclear translocation than the ST+ population, with these latter cells turning refractory to external stimuli such as TNF-α or a second infection. Sorting of ST+ and ST- cell populations confirmed enhanced expression of NF-κB target genes such asIL1B, NFKBIA, TNFAIP3, andTRAF1in uninfected (ST-) fibroblasts. These observations proved thatS. Typhimurium dampens the NF-κB response in the infected fibroblast. Higher expression ofSOCS3, encoding a “suppressor of cytokine signaling,” was also observed in the ST+ population. IntracellularS. Typhimurium subverts NF-κB activity using protein effectors translocated by the secretion systems encoded by pathogenicity islands 1 (T1) and 2 (T2). T1 is required for regulating expression ofSOCS3and all NF-κB target genes analyzed whereas T2 displayed no role in the control ofSOCS3andIL1Bexpression. Collectively, these data demonstrate thatS. Typhimurium attenuates NF-κB signaling in fibroblasts, an effect only perceptible when ST+ and ST- populations are analyzed separately. This tune-down in a central host defense might be instrumental forS. Typhimurium to establish intracellular persistent infections. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
16. NF-κB oscillations translate into functionally related patterns of gene expression.
- Author
-
Zambrano, Samuel, De Toma, Ilario, Piffer, Arianna, Bianchi, Marco E., and Agresti, Alessandra
- Published
- 2016
- Full Text
- View/download PDF
17. Histone content increases in differentiating embryonic stem cells.
- Author
-
Karnavas, Theodoros, Pintonello, Luisa, Agresti, Alessandra, and Bianchi, Marco E.
- Subjects
EMBRYONIC stem cell research ,PLURIPOTENT stem cells ,BLASTOCYST ,NEURONS ,CELL differentiation - Abstract
Mouse Embryonic Stem Cells (ESCs) are pluripotent mammalian cells derived from the Inner Cell Mass (ICM) of mouse blastocysts, which give rise to all three embryonic germ layers both in vivo and in vitro. Mouse ESCs have a distinct epigenetic landscape and a more decondensed chromatin compared to differentiated cells. Numerous studies have shown that distinct histone modifications in ESCs serve as hallmarks of pluripotency. However, so far it is still unknown whether the total histone content (as opposed to histone modifications) remains the same in cells of different developmental stage and differentiation capacity. In this work we show that total histone content differs between pluripotent and differentiated cells. In vitro spontaneous differentiation from ESCs to Embryoid Bodies (EBs) and directed differentiation toward neuronal and endodermal cells entails an increase in histone content. Primary MEFs also contain more histones than ESCs. We suggest that the difference in histone content is an additional hallmark of pluripotency, in addition to and besides histone modifications. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
18. High-Throughput Analysis of NF-κB Dynamics in Single Cells Reveals Basal Nuclear Localization of NF-κB and Spontaneous Activation of Oscillations.
- Author
-
Zambrano, Samuel, Bianchi, Marco E., and Agresti, Alessandra
- Subjects
HIGH throughput screening (Drug development) ,TRANSCRIPTION factors ,NF-kappa B ,CYTOPLASM ,OSCILLATIONS ,FIBROBLASTS - Abstract
NF-κB is a transcription factor that upon activation undergoes cycles of cytoplasmic-to-nuclear and nuclear-to-cytoplasmic transport, giving rise to so called “oscillations”. In turn, oscillations tune the transcriptional output. Since a detailed understanding of oscillations requires a systems biology approach, we developed a method to acquire and analyze large volumes of data on NF-κB dynamics in single cells. We measured the time evolution of the nuclear to total ratio of GFP-p65 in knock-in mouse embryonic fibroblasts using time-lapse imaging. We automatically produced a precise segmentation of nucleus and cytoplasm based on an accurate estimation of the signal and image background. Finally, we defined a set of quantifiers that describe the oscillatory dynamics, which are internally normalized and can be used to compare data recorded by different labs. Using our method, we analyzed NF-κB dynamics in over 2000 cells exposed to different concentrations of TNF- α α. We reproduced known features of the NF-κB system, such as the heterogeneity of the response in the cell population upon stimulation and we confirmed that a fraction of the responding cells does not oscillate. We also unveiled important features: the second and third oscillatory peaks were often comparable to the first one, a basal amount of nuclear NF-κB could be detected in unstimulated cells, and at any time a small fraction of unstimulated cells showed spontaneous random activation of the NF-κB system. Our work lays the ground for systematic, high-throughput, and unbiased analysis of the dynamics of transcription factors that can shuttle between the nucleus and other cell compartments. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
19. Rapamycin-sensitive signals control TCR/CD28-driven Ifng, Il4 and Foxp3 transcription and promoter region methylation.
- Author
-
Tomasoni, Romana, Basso, Veronica, Pilipow, Karolina, Sitia, Giovanni, Saccani, Simona, Agresti, Alessandra, Mietton, Flore, Natoli, Gioacchino, Colombetti, Sara, and Mondino, Anna
- Abstract
The mammalian target of rapamycin (mTOR) controls T-cell differentiation in response to polarizing cytokines. We previously found that mTOR blockade by rapamycin (RAPA) delays the G1-S cell cycle transition and lymphocyte proliferation. Here, we report that both mTOR complex 1 and mTOR complex 2 are readily activated following TCR/CD28 engagement and are critical for early expression of Ifng, Il4 and Foxp3, and for effector T cell differentiation in the absence of polarizing cytokines. While inhibition of mTOR complex 1 and cell division were evident at low doses of RAPA, inhibition of mTOR complex 2, Ifng, Il4 and Foxp3 expression, and T-cell polarization required higher doses and more prolonged treatments. We found that while T-bet and GATA3 were readily induced following TCR/CD28 engagement, administration of RAPA delayed their expression, and interfered with the loss of DNA methylation within Ifng and Il4 promoter regions. In contrast, RAPA prevented activation-dependent DNA methylation of the Foxp3 promoter favoring Foxp3 expression. As a result, RAPA-cultured cells lacked immediate effector functions and instead were enriched for IL-2 cells. We propose that mTOR-signaling, by timing the expression of critical transcription factors and DNA methylation of proximal promoter regions, regulates transcriptional competence at immunologically relevant sites and hence lymphocyte differentiation. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
20. Substantial Histone Reduction Modulates Genomewide Nucleosomal Occupancy and Global Transcriptional Output.
- Author
-
Celona, Barbara, Weiner, Assaf, Felice, Francesca Di, Francesco M.Mancuso, Cesarini, Elisa, Rossi, Riccardo L., Gregory, Lorna, Baban, Dilair, Rossetti, Grazisa, Grianti, Paolo, Pagani, Massimiliano, Bonaldi, Tiziana, Ragoussis, Jiannis, Friedman, Nir, Camilloni, Giorgio, Bianchi, Marco E., and Agresti, Alessandra
- Subjects
HISTONES ,GENOMES ,GENETIC transcription ,CELL nuclei ,YEAST fungi ,MAMMAL cytology - Abstract
The basic unit of genome packaging is the nucleosome, and nucleosomes have long been proposed to restrict DNA accessibility both to damage and to transcription. Nucleosome number in cells was considered fixed, but recently aging yeast and mammalian cells were shown to contain fewer nucleosomes. We show here that mammalian cells lacking High Mobility Group Box 1 protein (HMGB1) contain a reduced amount of core, linker, and variant histones, and a correspondingly reduced number of nucleosomes, possibly because HMGB1 facilitates nucleosome assembly. Yeast nhp6 mutants lacking Nhp6a and -b proteins, which are related to HMGB1, also have a reduced amount of histones and fewer nucleosomes. Nucleosome limitation in both mammalian and yeast cells increases the sensitivity of DNA to damage, increases transcription globally, and affects the relative expression of about 10% of genes. In yeast nhp6 cells the loss of more than one nucleosome in four does not affect the location of nucleosomes and their spacing, but nucleosomal occupancy. The decrease in nucleosomal occupancy is non-uniform and can be modelled assuming that different nucleosomal sites compete for available histones. Sites with a high propensity to occupation are almost always packaged into nucleosomes both in wild type and nucleosome-depleted cells; nucleosomes on sites with low propensity to occupation are disproportionately lost in nucleosome-depleted cells. We suggest that variation in nucleosome number, by affecting nucleosomal occupancy both genomewide and gene-specifically, constitutes a novel layer of epigenetic regulation. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
21. Sustained Oscillations of NF-κB Produce Distinct Genome Scanning and Gene Expression Profiles.
- Author
-
Myong-Hee Sung, Salvatore, Luigi, de Lorenzi, Rossana, Indrawan, Anindya, Pasparakis, Manolis, Hager, Gordon L., Bianchi, Marco E., and Agresti, Alessandra
- Subjects
MEDICAL research ,OSCILLATIONS ,GENOMES ,SCANNING electron microscopes ,GENE expression ,LABORATORY mice ,FIBROBLASTS ,MATHEMATICAL models ,CHROMOSOMAL translocation ,THERAPEUTICS - Abstract
NF-κB is a prototypic stress-responsive transcription factor that acts within a complex regulatory network. The signaling dynamics of endogenous NF-κB in single cells remain poorly understood. To examine real time dynamics in living cells, we monitored NF-κB activities at multiple timescales using GFP-p65 knock-in mouse embryonic fibroblasts. Oscillations in NFκB were sustained in most cells, with several cycles of transient nuclear translocation after TNF-α stimulation. Mathematical modeling suggests that NF-κB oscillations are selected over other non-oscillatory dynamics by fine-tuning the relative strengths of feedback loops like IκBa. The ability of NF-κB to scan and interact with the genome in vivo remained remarkably constant from early to late cycles, as observed by fluorescence recovery after photobleaching (FRAP). Perturbation of long-term NF-κB oscillations interfered with its short-term interaction with chromatin and balanced transcriptional output, as predicted by the mathematical model. We propose that negative feedback loops do not simply terminate signaling, but rather promote oscillations of NF-κB in the nucleus, and these oscillations are functionally advantageous. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
22. A hyper-dynamic equilibrium between promoter-bound and nucleoplasmic dimers controls NF-κB-dependent gene activity.
- Author
-
Bosisio, Daniela, Marazzi, Ivan, Agresti, Alessandra, Shimizu, Noriaki, Bianchi, Marco E, and Natoli, Gioacchino
- Subjects
GENES ,DNA ,NUCLEATION ,DIMERS ,TRANSCRIPTION factors ,CELLS - Abstract
Because of its very high affinity for DNA, NF-κB is believed to make long-lasting contacts with cognate sites and to be essential for the nucleation of very stable enhanceosomes. However, the kinetic properties of NF-κB interaction with cognate sites in vivo are unknown. Here, we show that in living cells NF-κB is immobilized onto high-affinity binding sites only transiently, and that complete NF-κB turnover on active chromatin occurs in less than 30 s. Therefore, promoter-bound NF-κB is in dynamic equilibrium with nucleoplasmic dimers; promoter occupancy and transcriptional activity oscillate synchronously with nucleoplasmic NF-κB and independently of promoter occupancy by other sequence-specific transcription factors. These data indicate that changes in the nuclear concentration of NF-κB directly impact on promoter function and that promoters sample nucleoplasmic levels of NF-κB over a timescale of seconds, thus rapidly re-tuning their activity. We propose a revision of the enhanceosome concept in this dynamic framework. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
23. HMG proteins: dynamic players in gene regulation and differentiation
- Author
-
Bianchi, Marco E and Agresti, Alessandra
- Subjects
- *
PROTEINS , *CHROMATIN , *GENETIC regulation , *GENETIC transcription , *TRANSCRIPTION factors - Abstract
Core histones package the genome into nucleosomes and control its accessibility to transcription factors. High mobility group proteins (HMGs) are, after histones, the second most abundant chromatin proteins and exert global genomic functions in establishing active or inactive chromatin domains. It is becoming increasingly clear that they also specifically control the expression of a limited number of genes. Moreover, they contribute to the fine tuning of transcription in response to rapid environmental changes. They do so by interacting with nucleosomes, transcription factors, nucleosome-remodelling machines, and with histone H1. [Copyright &y& Elsevier]
- Published
- 2005
- Full Text
- View/download PDF
24. GR and HMGB1 Interact Only within Chromatin and Influence Each Other’s Residence Time
- Author
-
Agresti, Alessandra, Scaffidi, Paola, Riva, Alberto, Caiolfa, Valeria R., and Bianchi, Marco E.
- Subjects
- *
NUCLEIC acids , *GLUCOCORTICOIDS , *ADRENOCORTICAL hormones - Abstract
Summary: Most nuclear proteins reside on a specific chromatin site only for seconds or less. The hit-and-run model of transcriptional control maintains that transcription complexes are assembled in a stochastic fashion from freely diffusible proteins; this contrasts to models involving stepwise assembly of stable holo complexes. However, the chances of forming a productive complex improve if the binding of one factor promotes the binding of its interactors. We prove here that in living cells, the glucocorticoid receptor and HMGB1 interact only within chromatin and not in the nucleoplasm and decrease each other’s mobility. Thus, the formation of a GR-HMGB1-chromatin complex is more likely than one would expect from independent binding to chromatin of GR and HMGB1. Remarkably, this complex is potentially stable, and its disassembly is effected by active, ATP-consuming processes. We propose that kinetic cooperativity among transcription factors in chromatin binding may be a common feature in transcription and DNA transactions. [Copyright &y& Elsevier]
- Published
- 2005
- Full Text
- View/download PDF
25. HMGB proteins and gene expression
- Author
-
Agresti, Alessandra and Bianchi, Marco E
- Subjects
- *
DNA-protein interactions , *CHROMATIN , *PROTEINS , *GENE expression - Abstract
High mobility group (HMG) proteins are chromatin proteins endowed with ‘architectural’ capabilities. HMGA proteins are moderately sequence-specific, and help build enhanceosomes by interacting with partner proteins and binding stably to the minor groove of DNA; their acetylation/deacetylation signal enhanceosome assembly or disassembly. HMGBs are much more dynamic proteins: they have no sequence specificity, and help transcription factors and other nuclear proteins bind to their cognate sites by bending the DNA molecule. However, HMGBs are rarely retained within the complex. Similarly, HMGBs interact with nucleosomes and promote their sliding, but remain bound only for fractions of a second. We argue that HMGBs fluidize chromatin — an action that appears opposite to that of histone H1. [Copyright &y& Elsevier]
- Published
- 2003
- Full Text
- View/download PDF
26. HMGB1 interacts differentially with members of the Rel family of transcription factors
- Author
-
Agresti, Alessandra, Lupo, Rossella, Bianchi, Marco E., and Müller, Susanne
- Subjects
- *
DNA-binding proteins , *GENETIC transcription - Abstract
HMGB1 is an architectural factor that enhances the DNA binding affinity of several proteins. We have investigated the influence of HMGB1 on DNA binding by members of the Rel family. HMGB1 enhances DNA binding by p65/p50 and p50/p50, but reduces binding by p65/p65, c-Rel/c-Rel, p65/c-Rel, and p50/c-Rel. In pull-down assays, HMGB1 interacts directly with the p50 subunit via its HMG boxes and this interaction is weakened by the presence of the acidic tail. Functionally, HMGB1 is required for the NF-κB-dependent expression of the adhesion molecule VCAM-1. [Copyright &y& Elsevier]
- Published
- 2003
- Full Text
- View/download PDF
27. The double life of HMGB1 chromatin protein: architectural factor and extracellular signal.
- Author
-
Müller, Susanne, Scaffidi, Paola, Degryse, Bernard, Bonaldi, Tiziana, Ronfani, Lorenza, Agresti, Alessandra, Beltrame, Monica, and Bianchi, Marco E.
- Subjects
CHROMOSOMAL proteins ,NUCLEOPROTEINS ,DNA ,NUCLEIC acids ,CELLS ,BIOMOLECULES - Abstract
This article focuses on the high mobility group box (HMGB) chromosomal proteins. The HMGB family comprises the three proteins HMGB1, HMGB2 and HMBG3. The structure of these three proteins is highly conserved, and their biochemical properties are so far indistinguishable. HMGBs are composed of three different domains. The localization of these proteins in most cells is nuclear. In their nuclear identity, HMGB1 and HMGB2 bind to the minor groove of DNA, causing a local distortion of the double helix. They have little or no sequence preference and they are recruited to the site of action by specific DNA binding proteins.
- Published
- 2001
- Full Text
- View/download PDF
28. To E or not to E?Can an IL-4-Induced B Cell Choose between IgE and IgG4?
- Author
-
Vercelli, Donata, De Monte, Lucia, Monticelli, Silvia, Di Bartolo, Chiara, and Agresti, Alessandra
- Subjects
B cells ,LYMPHOCYTES ,ANTIGEN presenting cells ,INTERLEUKIN-4 ,IMMUNOGLOBULIN E - Abstract
Parasite immunologists had known for some time that IgE-mediated hypersensitivity reactions are rare in patients with chronic helminth infections, even though basophils and mast cells in these patients are sensitized with antiparasite IgE and exposed, often continuously, to parasite antigens. The inhibition of allergic reactivity in chronic helminth infections is mainly due to IgG4 ‘blocking antibodies’ in the serum of the infected individual. IgG4 do not fix complement and bind weakly to Fcγ receptors. Thus, antigen binding by IgG4, unlike IgE, is likely to have no or minimally harmful consequences. The discovery that, similar to IgE, expression of IgG4 is IL-4-dependent and is an intermediate step in sequential switching from IgM to IgE makes it imperative to understand how the two isotypes are coregulated and whether the two responses can be uncoupled, selectively boosting IgG4 over IgE. The ultimate goal is to apply to allergy the lesson we learnt from helminth infections. [ABSTRACT FROM AUTHOR]
- Published
- 1998
- Full Text
- View/download PDF
29. Analysis of γ4 Germline Transcription in Human B Cells.
- Author
-
Agresti, Alessandra and Vercelli, Donata
- Subjects
- *
IMMUNOGLOBULIN G , *INTERLEUKIN-4 , *ALLERGIES , *HELMINTHIASIS , *ANTIGENS - Abstract
Background: Allergic reactions occur rarely in patients with chronic helminth infections, although FcεRI–bearing cells are sensitized with anti–parasite IgE and are exposed to antigen. The inhibition of allergic reactivity is due to ‘blocking antibodies’, predominantly IgG4. IgG4 antibodies represent 50–95% of anti–filarial IgG, and have blocking activity because they compete with cell–bound IgE for allergen binding. Blocking IgG4 antibodies have also been detected in patients treated with immunotherapy. However, the molecular mechanisms of IgG4 regulation have remained unexplored. We address this issue starting with the IL–4–dependent induction of γ4 germline transcription, an essential step in the commitment to isotype switching. Results: γ4 germline transcripts were cloned and shown to contain Iγ4 spliced to the 5′ portion of Cγ4 using the splice donor site shared by γ1 and γ3 germline transcripts. Sequence analysis located the human Iγ4 exon ≈0.6 kb upstream of the Sγ4 region. Four major transcription start sites located 547–583 bp upstream of the Iγ4 splice donor site were identified by primer extension analysis. A HindIII/NaeI construct (–413/+466) had the highest activity in reporter assays. Transcription was induced 4.6–fold by IL–4, 2.1–fold by CD40 engagement, and 14.5–fold by a combination of the two signals. Thus CD40 crosslinking enhanced IL–4–dependent transcription by 3.1–fold, showing that the two stimuli act synergistically. Conclusion: As we understand more about IgG4 regulation, our hope is to apply to allergy the lesson we learnt from helminth infections. [ABSTRACT FROM AUTHOR]
- Published
- 1999
- Full Text
- View/download PDF
30. NF-κB, the Importance of Being Dynamic: Role and Insights in Cancer.
- Author
-
Colombo, Federica, Zambrano, Samuel, and Agresti, Alessandra
- Subjects
NF-kappa B regulation ,CANCER invasiveness ,TUMOR growth ,CELL imaging ,MICROFLUIDICS - Abstract
In this review, we aim at describing the results obtained in the past years on dynamics features defining NF-κB regulatory functions, as we believe that these developments might have a transformative effect on the way in which NF-κB involvement in cancer is studied. We will also describe technical aspects of the studies performed in this context, including the use of different cellular models, culture conditions, microscopy approaches and quantification of the imaging data, balancing their strengths and limitations and pointing out to common features and to some open questions. Our emphasis in the methodology will allow a critical overview of literature and will show how these cutting-edge approaches can contribute to shed light on the involvement of NF-κB deregulation in tumour onset and progression. We hypothesize that this “dynamic point of view” can be fruitfully applied to untangle the complex relationship between NF-κB and cancer and to find new targets to restrain cancer growth. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
31. HMGBI MOLECULAR BIOLOGY IN MYELOID CELLS.
- Author
-
Bianchi, Marco E., Agresti, Alessandra, Bonaldi, Tiziana, Scaffi, Paola, Porto, Annalisa, Rubartelli, Anna, Bachi, Angela, and Manfredil, Angelo
- Published
- 2004
- Full Text
- View/download PDF
32. Detection of bovine leukaemia virus (BLV) infection by DNA probe technology
- Author
-
Gaudi, Simona, Ponti, Wilma, Agresti, Alessandra, Meneveri, Raffaella, Malcovati, Massimo, Bonizzi, Luigi, Poli, Giorgio, Amato, Aldo, and Ginelli, Enrico
- Published
- 1990
- Full Text
- View/download PDF
33. Interplay between stochasticity and negative feedback leads to pulsed dynamics and distinct gene activity patterns.
- Author
-
Zambrano, Samuel, Bianchi, Marco E., Agresti, Alessandra, and Molina, Nacho
- Subjects
- *
GENE regulatory networks , *STOCHASTIC processes , *PSYCHOLOGICAL feedback , *DYNAMICS , *HYBRID computer simulation - Abstract
Gene expression is an inherently stochastic process that depends on the structure of the biochemical regulatory network in which the gene is embedded. Here we study the dynamical consequences of the interplay between stochastic gene switching and the widespread negative feedback regulatory loop in a simple model of a biochemical regulatory network. Using a simplified hybrid simulation approach, in which only the gene activation is modeled stochastically, we find that stochasticity in gene switching by itself can induce pulses in the system, providing also analytical insights into their origin. Furthermore, we find that this simple network is able to reproduce both exponential and peaked distributions of gene active and inactive times similar to those that have been observed experimentally. This simplified hybrid simulation approach also allows us to link these patterns to the dynamics of the system for each gene state. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
34. A simple model of dynamics reproduces experimental observations.
- Author
-
Zambrano, Samuel, Bianchi, Marco E., and Agresti, Alessandra
- Subjects
- *
EXPERIMENTAL biology , *BIOLOGICAL models , *TRANSCRIPTION factors , *CELLULAR signal transduction , *GENE expression , *DRUG administration , *CELLULAR pathology - Abstract
Abstract: The mathematical modeling of the oscillations has attracted considerable attention in recent times, but there is a lack of simple models in the literature that can capture the main features of the dynamics of this important transcription factor. For this reason we propose a simple model that summarizes the key steps of the pathway. We show that the resulting 5-dimensional dynamical system can reproduce different phenomena observed in experiments. Our model can display smooth and spiky oscillations in the amount of nuclear and can reproduce the variety of dynamics observed when different stimulations such as and LPS are used. Furthermore we show that the model can be easily extended to reproduce the expression of early, intermediate and late genes upon stimulation. As a final example we show that our simple model can mimic the different transcriptional outputs observed when cells are treated with two different drugs leading to nuclear localization of : Leptomycin B and Cycloheximide. [Copyright &y& Elsevier]
- Published
- 2014
- Full Text
- View/download PDF
35. CXCL10 levels at hospital admission predict COVID-19 outcome: hierarchical assessment of 53 putative inflammatory biomarkers in an observational study.
- Author
-
Lorè, Nicola I., De Lorenzo, Rebecca, Rancoita, Paola M. V., Cugnata, Federica, Agresti, Alessandra, Benedetti, Francesco, Bianchi, Marco E., Bonini, Chiara, Capobianco, Annalisa, Conte, Caterina, Corti, Angelo, Furlan, Roberto, Mantegani, Paola, Maugeri, Norma, Sciorati, Clara, Saliu, Fabio, Silvestri, Laura, Tresoldi, Cristina, Bio Angels for COVID-BioB Study Group, and Farina, Nicola
- Subjects
- *
CHEMOKINES , *COVID-19 , *HOSPITAL admission & discharge , *PROGNOSIS , *NEUTROPHIL lymphocyte ratio , *LACTATE dehydrogenase , *CALCITONIN - Abstract
Background: Host inflammation contributes to determine whether SARS-CoV-2 infection causes mild or life-threatening disease. Tools are needed for early risk assessment. Methods: We studied in 111 COVID-19 patients prospectively followed at a single reference Hospital fifty-three potential biomarkers including alarmins, cytokines, adipocytokines and growth factors, humoral innate immune and neuroendocrine molecules and regulators of iron metabolism. Biomarkers at hospital admission together with age, degree of hypoxia, neutrophil to lymphocyte ratio (NLR), lactate dehydrogenase (LDH), C-reactive protein (CRP) and creatinine were analysed within a data-driven approach to classify patients with respect to survival and ICU outcomes. Classification and regression tree (CART) models were used to identify prognostic biomarkers. Results: Among the fifty-three potential biomarkers, the classification tree analysis selected CXCL10 at hospital admission, in combination with NLR and time from onset, as the best predictor of ICU transfer (AUC [95% CI] = 0.8374 [0.6233–0.8435]), while it was selected alone to predict death (AUC [95% CI] = 0.7334 [0.7547–0.9201]). CXCL10 concentration abated in COVID-19 survivors after healing and discharge from the hospital. Conclusions: CXCL10 results from a data-driven analysis, that accounts for presence of confounding factors, as the most robust predictive biomarker of patient outcome in COVID-19. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
36. Aspirin′s Active Metabolite Salicylic Acid Targets High Mobility Group Box 1 to Modulate Inflammatory Responses.
- Author
-
Hyong Woo Choi, Miaoying Tian, Fei Song, Venereau, Emilie, Preti, Alessandro, Sang-Wook Park, Hamilton, Keith, Swapna, G. V. T., Manohar, Murli, Moreau, Magali, Agresti, Alessandra, Gorzanelli, Andrea, De Marchis, Francesco, Huang Wang, Antonyak, Marc, Micikas, Robert J., Gentile, Daniel R., Cerione, Richard A., Schroeder, Frank C., and Montelione, Gaetano T.
- Abstract
Salicylic acid (SA) and its derivatives have been used for millennia to reduce pain, fever and inflammation. In addition, prophylactic use of acetylsalicylic acid, commonly known as aspirin, reduces the risk of heart attack, stroke and certain cancers. Because aspirin is rapidly de-acetylated by esterases in human plasma, much of aspirin’s bioactivity can be attributed to its primary metabolite, SA. Here we demonstrate that human high mobility group box 1 (HMGB1) is a novel SA-binding protein. SA-binding sites on HMGB1 were identified in the HMG-box domains by nuclear magnetic resonance (NMR) spectroscopic studies and confirmed by mutational analysis. Extracellular HMGB1 is a damage-associated molecular pattern molecule (DAMP), with multiple redox states. SA suppresses both the chemoattractant activity of fully reduced HMGB1 and the increased expression of proinflammatory cytokine genes and cyclooxygenase 2 (COX-2) induced by disulfide HMGB1. Natural and synthetic SA derivatives with greater potency for inhibition of HMGB1 were identified, providing proof-of-concept that new molecules with high efficacy against sterile inflammation are attainable. An HMGB1 protein mutated in one of the SA-binding sites identified by NMR chemical shift perturbation studies retained chemoattractant activity, but lost binding of and inhibition by SA and its derivatives, thereby firmly establishing that SA binding to HMGB1 directly suppresses its proinflammatory activities. Identification of HMGB1 as a pharmacological target of SA/aspirin provides new insights into the mechanisms of action of one of the world’s longest and most used natural and synthetic drugs. It may also provide an explanation for the protective effects of low-dose aspirin usage. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
37. Receptor for Advanced Glycation Endproducts is upregulated in temporal lobe epilepsy and contributes to experimental seizures.
- Author
-
Iori, Valentina, Maroso, Mattia, Rizzi, Massimo, Iyer, Anand M., Vertemara, Roberta, Carli, Mirjana, Agresti, Alessandra, Antonelli, Antonella, Bianchi, Marco E., Aronica, Eleonora, Ravizza, Teresa, and Vezzani, Annamaria
- Subjects
- *
GLYCOSYLATION , *TEMPORAL lobe epilepsy , *SPASMS , *TOLL-like receptors , *ASTROCYTES , *HIGH mobility group proteins , *LABORATORY mice - Abstract
Abstract: Toll-like receptor 4 (TLR4) activation in neuron and astrocytes by High Mobility Group Box 1 (HMGB1) protein is a key mechanism of seizure generation. HMGB1 also activates the Receptor for Advanced Glycation Endproducts (RAGE), but it was unknown whether RAGE activation contributes to seizures or to HMGB1 proictogenic effects. We found that acute EEG seizures induced by 7ng intrahippocampal kainic acid (KA) were significantly reduced in Rage−/− mice relative to wild type (Wt) mice. The proictogenic effect of HMGB1 was decreased in Rage−/− mice, but less so, than in Tlr4−/− mice. In a mouse mesial temporal lobe epilepsy (mTLE) model, status epilepticus induced by 200ng intrahippocampal KA and the onset of the spontaneous epileptic activity were similar in Rage−/−, Tlr4−/− and Wt mice. However, the number of hippocampal paroxysmal episodes and their duration were both decreased in epileptic Rage−/− and Tlr4−/− mice vs Wt mice. All strains of epileptic mice displayed similar cognitive deficits in the novel object recognition test vs the corresponding control mice. CA1 neuronal cell loss was increased in epileptic Rage−/− vs epileptic Wt mice, while granule cell dispersion and doublecortin (DCX)-positive neurons were similarly affected. Notably, DCX neurons were preserved in epileptic Tlr4−/− mice. We did not find compensatory changes in HMGB1-related inflammatory signaling nor in glutamate receptor subunits in Rage−/− and Tlr4−/− naïve mice, except for ~20% NR2B subunit reduction in Rage−/− mice. RAGE was induced in neurons, astrocytes and microvessels in human and experimental mTLE hippocampi. We conclude that RAGE contributes to hyperexcitability underlying acute and chronic seizures, as well as to the proictogenic effects of HMGB1. RAGE and TLR4 play different roles in the neuropathologic sequelae developing after status epilepticus. These findings reveal new molecular mechanisms underlying seizures, cell loss and neurogenesis which involve inflammatory pathways upregulated in human epilepsy. [Copyright &y& Elsevier]
- Published
- 2013
- Full Text
- View/download PDF
38. Glycyrrhizin Binds to High-Mobility Group Box 1 Protein and Inhibits Its Cytokine Activities
- Author
-
Mollica, Luca, De Marchis, Francesco, Spitaleri, Andrea, Dallacosta, Corrado, Pennacchini, Danilo, Zamai, Moreno, Agresti, Alessandra, Trisciuoglio, Lisa, Musco, Giovanna, and Bianchi, Marco E.
- Subjects
- *
CELLULAR immunity , *SEPSIS , *JOINT diseases , *NUCLEIC acids - Abstract
Summary: High-mobility group box 1 protein (HMGB1) is a nuclear component, but extracellularly it serves as a signaling molecule involved in acute and chronic inflammation, for example in sepsis and arthritis. The identification of HMGB1 inhibitors is therefore of significant experimental and clinical interest. We show that glycyrrhizin, a natural anti-inflammatory and antiviral triterpene in clinical use, inhibits HMGB1 chemoattractant and mitogenic activities, and has a weak inhibitory effect on its intranuclear DNA-binding function. NMR and fluorescence studies indicate that glycyrrhizin binds directly to HMGB1 (Kd ∼150 μM), interacting with two shallow concave surfaces formed by the two arms of both HMG boxes. Our results explain in part the anti-inflammatory properties of glycyrrhizin, and might direct the design of new derivatives with improved HMGB1-binding properties. [Copyright &y& Elsevier]
- Published
- 2007
- Full Text
- View/download PDF
39. Exploiting Live Imaging to Track Nuclei During Myoblast Differentiation and Fusion.
- Author
-
Careccia G, Colombo F, Tirone M, Agresti A, Bianchi ME, Zambrano S, and Vénéreau E
- Subjects
- Animals, Cell Fusion, Cell Survival, Mice, Muscle, Skeletal cytology, Satellite Cells, Skeletal Muscle cytology, Cell Differentiation, Cell Nucleus metabolism, Molecular Imaging, Myoblasts cytology
- Abstract
Nuclear positioning within cells is important for multiple cellular processes in development and regeneration. The most intriguing example of nuclear positioning occurs during skeletal muscle differentiation. Muscle fibers (myofibers) are multinucleated cells formed by the fusion of muscle precursor cells (myoblasts) derived from muscle stem cells (satellite cells) that undergo proliferation and differentiation. Correct nuclear positioning within myofibers is required for the proper muscle regeneration and function. The common procedure to assess myoblast differentiation and myofiber formation relies on fixed cells analyzed by immunofluorescence, which impedes the study of nuclear movement and cell behavior over time. Here, we describe a method for the analysis of myoblast differentiation and myofiber formation by live cell imaging. We provide a software for automated nuclear tracking to obtain a high-throughput quantitative characterization of nuclear dynamics and myoblast behavior (i.e., the trajectory) during differentiation and fusion.
- Published
- 2019
- Full Text
- View/download PDF
40. Single-cell analyses reveal an attenuated NF-κB response in the Salmonella-infected fibroblast.
- Author
-
Ramos-Marquès E, Zambrano S, Tiérrez A, Bianchi ME, Agresti A, and García-Del Portillo F
- Subjects
- Cell Line, Fibroblasts drug effects, Fibroblasts metabolism, Humans, Interleukin-1beta genetics, Microfluidics, NF-KappaB Inhibitor alpha genetics, NF-kappa B genetics, Salmonella typhimurium drug effects, Salmonella typhimurium metabolism, Signal Transduction, Single-Cell Analysis, Suppressor of Cytokine Signaling 3 Protein genetics, TNF Receptor-Associated Factor 1 genetics, Time-Lapse Imaging, Tumor Necrosis Factor alpha-Induced Protein 3 genetics, Tumor Necrosis Factor-alpha pharmacology, Fibroblasts microbiology, NF-kappa B metabolism, Salmonella typhimurium pathogenicity
- Abstract
The eukaryotic transcriptional regulator Nuclear Factor kappa B (NF-κB) plays a central role in the defense to pathogens. Despite this, few studies have analyzed NF-κB activity in single cells during infection. Here, we investigated at the single cell level how NF-κB nuclear localization - a proxy for NF-κB activity - oscillates in infected and uninfected fibroblasts co-existing in cultures exposed to Salmonella enterica serovar Typhimurium. Fibroblasts were used due to the capacity of S. Typhimurium to persist in this cell type. Real-time dynamics of NF-κB was examined in microfluidics, which prevents cytokine accumulation. In this condition, infected (ST+) cells translocate NF-κB to the nucleus at higher rate than the uninfected (ST-) cells. Surprisingly, in non-flow (static) culture conditions, ST- fibroblasts exhibited higher NF-κB nuclear translocation than the ST+ population, with these latter cells turning refractory to external stimuli such as TNF-α or a second infection. Sorting of ST+ and ST- cell populations confirmed enhanced expression of NF-κB target genes such as IL1B, NFKBIA, TNFAIP3, and TRAF1 in uninfected (ST-) fibroblasts. These observations proved that S. Typhimurium dampens the NF-κB response in the infected fibroblast. Higher expression of SOCS3, encoding a "suppressor of cytokine signaling," was also observed in the ST+ population. Intracellular S. Typhimurium subverts NF-κB activity using protein effectors translocated by the secretion systems encoded by pathogenicity islands 1 (T1) and 2 (T2). T1 is required for regulating expression of SOCS3 and all NF-κB target genes analyzed whereas T2 displayed no role in the control of SOCS3 and IL1B expression. Collectively, these data demonstrate that S. Typhimurium attenuates NF-κB signaling in fibroblasts, an effect only perceptible when ST+ and ST- populations are analyzed separately. This tune-down in a central host defense might be instrumental for S. Typhimurium to establish intracellular persistent infections.
- Published
- 2017
- Full Text
- View/download PDF
41. Sustained oscillations of NF-kappaB produce distinct genome scanning and gene expression profiles.
- Author
-
Sung MH, Salvatore L, De Lorenzi R, Indrawan A, Pasparakis M, Hager GL, Bianchi ME, and Agresti A
- Subjects
- Animals, Cell Nucleus metabolism, Chromatin metabolism, Cycloheximide pharmacology, Cytoplasm metabolism, Feedback, Physiological, Fibroblasts metabolism, Fluorescence Recovery After Photobleaching, Green Fluorescent Proteins metabolism, Mice, Models, Theoretical, Gene Expression Profiling, Genome, NF-kappa B metabolism, Oscillometry methods
- Abstract
NF-kappaB is a prototypic stress-responsive transcription factor that acts within a complex regulatory network. The signaling dynamics of endogenous NF-kappaB in single cells remain poorly understood. To examine real time dynamics in living cells, we monitored NF-kappaB activities at multiple timescales using GFP-p65 knock-in mouse embryonic fibroblasts. Oscillations in NF-kappaB were sustained in most cells, with several cycles of transient nuclear translocation after TNF-alpha stimulation. Mathematical modeling suggests that NF-kappaB oscillations are selected over other non-oscillatory dynamics by fine-tuning the relative strengths of feedback loops like IkappaBalpha. The ability of NF-kappaB to scan and interact with the genome in vivo remained remarkably constant from early to late cycles, as observed by fluorescence recovery after photobleaching (FRAP). Perturbation of long-term NF-kappaB oscillations interfered with its short-term interaction with chromatin and balanced transcriptional output, as predicted by the mathematical model. We propose that negative feedback loops do not simply terminate signaling, but rather promote oscillations of NF-kappaB in the nucleus, and these oscillations are functionally advantageous.
- Published
- 2009
- Full Text
- View/download PDF
42. A hyper-dynamic equilibrium between promoter-bound and nucleoplasmic dimers controls NF-kappaB-dependent gene activity.
- Author
-
Bosisio D, Marazzi I, Agresti A, Shimizu N, Bianchi ME, and Natoli G
- Subjects
- Biological Clocks physiology, HeLa Cells, Humans, Protein Binding physiology, Time Factors, Cell Nucleus metabolism, Chromatin metabolism, DNA metabolism, NF-kappa B metabolism, Promoter Regions, Genetic physiology, Transcription, Genetic physiology
- Abstract
Because of its very high affinity for DNA, NF-kappaB is believed to make long-lasting contacts with cognate sites and to be essential for the nucleation of very stable enhanceosomes. However, the kinetic properties of NF-kappaB interaction with cognate sites in vivo are unknown. Here, we show that in living cells NF-kappaB is immobilized onto high-affinity binding sites only transiently, and that complete NF-kappaB turnover on active chromatin occurs in less than 30 s. Therefore, promoter-bound NF-kappaB is in dynamic equilibrium with nucleoplasmic dimers; promoter occupancy and transcriptional activity oscillate synchronously with nucleoplasmic NF-kappaB and independently of promoter occupancy by other sequence-specific transcription factors. These data indicate that changes in the nuclear concentration of NF-kappaB directly impact on promoter function and that promoters sample nucleoplasmic levels of NF-kappaB over a timescale of seconds, thus rapidly re-tuning their activity. We propose a revision of the enhanceosome concept in this dynamic framework.
- Published
- 2006
- Full Text
- View/download PDF
43. Monocytic cells hyperacetylate chromatin protein HMGB1 to redirect it towards secretion.
- Author
-
Bonaldi T, Talamo F, Scaffidi P, Ferrera D, Porto A, Bachi A, Rubartelli A, Agresti A, and Bianchi ME
- Subjects
- Acetylation, Amino Acid Sequence, Animals, Base Sequence, Cells, Cultured, Electrophoresis, Gel, Two-Dimensional, HMGB1 Protein chemistry, HMGB1 Protein genetics, HMGB1 Protein isolation & purification, HeLa Cells, Humans, Karyopherins genetics, Karyopherins metabolism, Mice, Molecular Sequence Data, Peptide Fragments chemistry, Protein Biosynthesis, Recombinant Fusion Proteins metabolism, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization, Transcription, Genetic, Exportin 1 Protein, HMGB1 Protein physiology, Inflammation physiopathology, Monocytes physiology, Receptors, Cytoplasmic and Nuclear
- Abstract
High Mobility Group 1 protein (HMGB1) is a chromatin component that, when leaked out by necrotic cells, triggers inflammation. HMGB1 can also be secreted by activated monocytes and macrophages, and functions as a late mediator of inflammation. Secretion of a nuclear protein requires a tightly controlled relocation program. We show here that in all cells HMGB1 shuttles actively between the nucleus and cytoplasm. Monocytes and macrophages acetylate HMGB1 extensively upon activation with lipopolysaccharide; moreover, forced hyperacetylation of HMGB1 in resting macrophages causes its relocalization to the cytosol. Cytosolic HMGB1 is then concentrated by default into secretory lysosomes, and secreted when monocytic cells receive an appropriate second signal.
- Published
- 2003
- Full Text
- View/download PDF
44. Association of chromatin proteins high mobility group box (HMGB) 1 and HMGB2 with mitotic chromosomes.
- Author
-
Pallier C, Scaffidi P, Chopineau-Proust S, Agresti A, Nordmann P, Bianchi ME, and Marechal V
- Subjects
- 3T3 Cells, Animals, Cell Membrane metabolism, Cells, Cultured, Chromatin physiology, Green Fluorescent Proteins, HMGN Proteins metabolism, HeLa Cells, Humans, Luminescent Proteins, Mice, Mitosis physiology, Permeability, Recombinant Proteins, Red Fluorescent Protein, Chromatin metabolism, Chromosomes metabolism, HMGB1 Protein metabolism, HMGB2 Protein metabolism
- Abstract
High mobility group box (HMGB) 1 and 2 are two abundant nonhistone nuclear proteins that have been found in association with chromatin. Previous studies based on immunofluorescence analysis indicated that HMGB1 dissociates from chromosomes during mitosis. In the present work, HMGB1 and 2 subcellular localization was reinvestigated in living cells by using enhanced green fluorescent protein- and Discosome sp. red fluorescent protein-tagged proteins. Contrary to previous reports, HMGB1 and 2 were shown to be present under two forms in mitotic cells, i.e., free and associated with the condensed chromatin, which rapidly exchange. A detailed analysis of HMGB2 interaction with mitotic chromosomes indicated that two sites encompassing HMG-box A and B are responsible for binding. Importantly, this interaction was rapidly inactivated when cells were permeabilized or exposed to chemical fixatives that are widely used in immunodetection techniques. A comparable behavior was also observed for two proteins of the HMG-nucleosome binding (HMGN) group, namely, HMGN1 and HMGN2.
- Published
- 2003
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.