Repenser l’intelligence collective au prisme des « nouvelles masses »

La multiplication des bouleversements récents, de nature à la fois écologique, politique, sociale et économique, nous invite à reconsidérer en profondeur non seulement nos modes de vie et nos pratiques mais également nos catégories de pensée, qui leur sont indissociables. L’ampleur et la radicalité des enjeux contemporains, en partie liés au système productif et économique mis en place après la Révolution industrielle, ont tout particulièrement mis en crise, depuis quelques années, l’un des f..

La démocratie à l’épreuve du numérique

Manon Delobel : Charles Girard, vous êtes philosophe et maître de conférences en philosophie politique à l’Université Lyon III, spécialiste des théories de la démocratie et des droits fondamentaux. En 2019, vous avez publié un ouvrage intitulé Délibérer entre égaux. Enquête sur l'idéal démocratique ; vous y critiquez les théories dites « réalistes » qui écartent « l’idéal démocratique » comme une chimère. Pouvez-vous revenir d’abord sur ce que vous appelez l’« idéal démocratique » et sur les ..

Pour un « libéralisme poétique » : réforme de l’entendement et démocratie dans la pensée de María Zambrano

La philosophie politique du premier xxe siècle affronte la crise du libéralisme. Dans un contexte de Grande Dépression, de conflits sociaux et d’affrontements internationaux, cette crise dévoile l’insuffisance du principe du laissez-faire dans la conduite du gouvernement. La doctrine du libre-marché, marquée par un refus de tout interventionnisme, n’est pas parvenue à intégrer les données nouvelles de la société industrielle mondialisée et des mutations du capitalisme. Parallèlement à ce cons..

Severe Muscle Deconditioning Triggers Early Extracellular Matrix Remodeling and Resident Stem Cell Differentiation into Adipocytes in Healthy Men

International audienceBesides the loss of muscle mass and strength, increased intermuscular adipose tissue (IMAT) is now a well-recognized consequence of muscle deconditioning as experienced in prolonged microgravity. IMAT content may alter the muscle stem cell microenvironment. We hypothesized that extracellular matrix structure alterations and microenvironment remodeling induced by fast and severe muscle disuse could modulate fibro-adipogenic progenitor fate and behavior. We used the dry immersion (DI) model that rapidly leads to severe muscle deconditioning due to drastic hypoactivity. We randomly assigned healthy volunteers (n = 18 men) to the control group (only DI, n = 9; age = 33.8 ± 4) or to the DI + thigh cuff group (n = 9; age = 33.4 ± 7). Participants remained immersed in the supine position in a thermo-neutral water bath for 5 days. We collected vastus lateralis biopsies before (baseline) and after DI. 5 days of DI are sufficient to reduce muscle mass significantly, as indicated by the decreased myofiber cross-sectional area in vastus lateralis samples (−18% vs. baseline, p < 0.05). Early and late adipogenic differentiation transcription factors protein levels were upregulated. Platelet-derived growth Factors alpha (PDGFR⍺) protein level and PDGFR⍺-positive cells were increased after 5 days of DI. Extracellular matrix structure was prone to remodeling with an altered ECM composition with 4 major collagens, fibronectin, and Connective Tissue Growth Factor mRNA decreases (p < 0.001 vs. baseline). Wearing thigh cuffs did not have any preventive effect on the measured variable. Our results show that altered extracellular matrix structure and signaling pathways occur early during DI, a severe muscle wasting model, favoring fibro-adipogenic progenitor differentiation into adipocytes

Th22 cells are efficiently recruited in the gut by CCL28 as an alternative to CCL20 but do not compensate for the loss of Th17 cells in treated HIV-1-infected individuals

International audienceGut CD4+ T cells are incompletely restored in most HIV-1-infected individuals on antiretroviral therapy, notably Th17 cells, a key subset in mucosal homeostasis. By contrast, gut Th22 cells are usually restored at normal frequencies. Th22 cells display a CCR6+CCR10+ phenotype and could thus respond to CCL20- and CCL28-mediated chemotaxis, while Th17 cells, which express CCR6 but not CCR10, depend on CCL20. Herein, we found that CCL28 is normally expressed by duodenal enterocytes of treated HIV-1-infected individuals, while CCL20 expression is blunted. Ex vivo, we showed that Th22 cells contribute to the reduction of CCL20 production by enterocytes through an IL-22- and IL-18-dependent mechanism. Th22 cells preferentially migrate via CCL20- rather than CCL28-mediated chemotaxis when both chemokines are available in the microenvironment. However, when the CCL20/CCL28 ratio drops, as in treated HIV-1-infected individuals, Th22 cells can migrate via the CCR10-CCL28 axis, as an alternative to CCR6-CCL20. This could explain the better reconstitution of gut Th22 compared with Th17 cells on antiretroviral therapy. Lastly, we assessed the relationships between the frequencies of gut Th17 and Th22 cells and inflammatory markers related to microbial translocation, and showed that Th22 cells do not compensate for the loss of Th17 cells in treated HIV-1-infected individuals

Comparing ultrafiltration and equilibrium dialysis to measure unbound plasma dolutegravir concentrations based on a design of experiment approach

International audienceDolutegravir therapeutic drug monitoring (TDM) could be improved by measuring the unbound dolutegravir plasma concentration (Cu), particularly in patients experiencing virological failure or toxicity despite achieving appropriate DTG total plasma concentrations. Equilibrium dialysis (ED) is the gold standard to measure Cu, but ED is time consuming, precluding its use in clinical practice. In contrast, ultrafiltration is applicable to TDM, but is sensitive to numerous analytical conditions. In order to evaluate measurements of Cu by ultrafiltration, ultrafiltration conditions were validated by comparison with ED. DTG concentrations were measured by LC-MS/MS. Three ultrafiltration factors (temperature, duration and relative centrifugal force [RCF]) were evaluated and compared to ED (25/37 °C), using a design of experiment strategy. Temperature was found to influence Cu results by ED (p = 0.036) and UF (p = 0.002) when results were analysed with ANOVA. Relative centrifugal force (2000 g) and time (20 min) interacted to influence Cu (p = 0.006), while individually they did not influence Cu (p = 0.88 and p = 0.42 for RCF and time). Ultrafiltration conditions which yielded the most comparable results to ED were 37 °C, 1000 g for 20 min. Ultrafiltration results greatly depended on analytical conditions, confirming the need to validate the method by comparison with ED in order to correctly interpret DTG Cu

Intact proviruses are enriched in the colon and associated with PD-1+TIGIT− mucosal CD4+ T cells of people with HIV-1 on antiretroviral therapyResearch in context

Summary: Background: The persistence of intact replication-competent HIV-1 proviruses is responsible for the virological rebound off treatment. The gut could be a major reservoir of HIV-1 due to the high number of infected target cells. Methods: We collected blood samples and intestinal biopsies (duodenum, ileum, colon) from 42 people with HIV-1 receiving effective antiretroviral therapy. We used the Intact Proviral DNA Assay to estimate the frequency of intact HIV-1 proviruses in the blood and in the intestinal mucosa of these individuals. We analyzed the genetic complexity of the HIV-1 reservoir by performing single-molecule next-generation sequencing of HIV-1 env DNA. The activation/exhaustion profile of mucosal T lymphocytes was assessed by flow cytometry. Findings: Intact proviruses are particularly enriched in the colon. Residual HIV-1 transcription in the gut is associated with persistent mucosal and systemic immune activation. The HIV-1 intestinal reservoir appears to be shaped by the proliferation of provirus-hosting cells. The genetic complexity of the viral reservoir in the colon is positively associated with TIGIT expression but negatively with PD-1, and inversely related to its intact content. The size of the intact reservoir in the colon is associated with PD-1+TIGIT− mucosal CD4+ T cells, particularly in CD27+ memory cells, whose proliferation and survival could contribute to the enrichment of the viral reservoir by intact proviruses. Interpretation: Enrichment in intact proviruses makes the gut a key compartment for HIV-1 persistence on antiretroviral therapy. Funding: This project was supported by grants from the ANRS-MIE (ANRS EP61 GALT), Sidaction, and the Institut Universitaire de France

Hepatitis E virus replication in human intestinal cells

International audienceHepatitis E virus (HEV), one of the most common agent of acute hepatitis worldwide, is mainly transmitted enterically, via contaminated water for HEV genotypes 1 (HEV1) and HEV2, or by eating raw or undercooked infected meat for HEV genotype 3 (HEV3) and HEV4. However, little is known about how the ingested HEV reaches the liver or its ability to replicate in intestinal cells. We developed human primary cultures of small intestine epithelial cells and intestinal explants obtained from small bowel resections. The epithelial cells were also polarised on transwells. Cells were infected with Kernow-p6 strain or clinically derived virions. Primary intestinal cells supported the growth of Kernow-p6 strain and HEV1 and HEV3 clinically derived virions. Polarised enterocytes infected with HEV1 and HEV3 strains released HEV particles vectorially: mostly into the apical compartment with a little basally. Iodixanol density gradient centrifugation of enterocyte-derived HEV virions gave bands at a density of 1.06-1.08 g/cm3, corresponding to that of quasi-enveloped HEV particles. Ribavirin therapy inhibited HEV excretion from the basal surface but not from the apical side of infected human enterocytes. HEV virions also infected intestinal tissue explants. Lastly, HEV RNA and antigen were detected in the intestinal crypts of a chronically infected patient. HEV can replicate in intestinal cells and reaches the liver as quasi-enveloped virions