Enhanced anti-HCV activity of interferon alpha 17 subtype

<p>Abstract</p> <p>Background</p> <p>Pegylated interferon alpha 2 (a or b) plus ribavirin is the most effective treatment of chronic hepatitis C but a large proportion of patients do not respond to therapy. So, it is interesting to improve the treatment efficacy. Interferon alpha is a type I interferon composed of 12 different subtypes. Each subtype signals by the Jak-Stat pathway but modulations in the antiviral activity was previously described.</p> <p>Methods</p> <p>Using the hepatitis C virus (HCV) culture system, we have tested the anti-HCV activity of each interferon alpha subtypes. We have analyzed the effect of each subtype on the HCV multiplication and the cell-signaling pathway for some subtypes.</p> <p>Results</p> <p>There were divergent effects of IFN alpha subtypes against HCV. We have found that IFN alpha 17 was three times more efficient than IFN alpha 2a on HCV. This efficiency was related to a stronger stimulation of the Jak-Stat pathway.</p> <p>Conclusion</p> <p>We suggest that IFN α17 should be tested therapeutically with a view to improving treatment efficacy.</p

Perinatal acquisition of drug-resistant HIV-1 infection: mechanisms and long-term outcome

<p>Abstract</p> <p>Background</p> <p>Primary-HIV-1-infection in newborns that occurs under antiretroviral prophylaxis that is a high risk of drug-resistance acquisition. We examine the frequency and the mechanisms of resistance acquisition at the time of infection in newborns.</p> <p>Patients and Methods</p> <p>We studied HIV-1-infected infants born between 01 January 1997 and 31 December 2004 and enrolled in the ANRS-EPF cohort. HIV-1-RNA and HIV-1-DNA samples obtained perinatally from the newborn and mother were subjected to population-based and clonal analyses of drug resistance. If positive, serial samples were obtained from the child for resistance testing.</p> <p>Results</p> <p>Ninety-two HIV-1-infected infants were born during the study period. Samples were obtained from 32 mother-child pairs and from another 28 newborns. Drug resistance was detected in 12 newborns (20%): drug resistance to nucleoside reverse transcriptase inhibitors was seen in 10 cases, non-nucleoside reverse transcriptase inhibitors in two cases, and protease inhibitors in one case. For 9 children, the detection of the same resistance mutations in mothers' samples (6 among 10 available) and in newborn lymphocytes (6/8) suggests that the newborn was initially infected by a drug-resistant strain. Resistance variants were either transmitted from mother-to-child or selected during subsequent temporal exposure under suboptimal perinatal prophylaxis. Follow-up studies of the infants showed that the resistance pattern remained stable over time, regardless of antiretroviral therapy, suggesting the early cellular archiving of resistant viruses. The absence of resistance in the mother of the other three children (3/10) and neonatal lymphocytes (2/8) suggests that the newborns were infected by a wild-type strain without long-term persistence of resistance when suboptimal prophylaxis was stopped.</p> <p>Conclusion</p> <p>This study confirms the importance of early resistance genotyping of HIV-1-infected newborns. In most cases (75%), drug resistance was archived in the cellular reservoir and persisted during infancy, with or without antiretroviral treatment. This finding stresses the need for effective antiretroviral treatment of pregnant women.</p

Contribution aux langages de 4eme generation, orientes vers les systemes de conduite et de diagnostic de pannes d'installations industrielles

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Le confort en bouche est amélioré pour les personnes âgées ayant une mauvaise dentition lors de la consommation de produits carnés adaptés

International audienc

Schistosoma mansoni Activates Host Microvascular Endothelial Cells To Acquire an Anti-Inflammatory Phenotype

Since endothelial cells (ECs) play a key role in immune defense mechanisms and in immunopathology, we investigated whether the intravascular helminth parasite Schistosoma mansoni could interact with and activate resting ECs in vitro. Microscopic analysis revealed that the lung-stage schistosomula specifically attached to microvascular ECs. This adherence was associated to active cellular processes involving actin filament formation. Since variation of permeability of cultured capillary brain ECs is a good marker for endothelial activation, the transendothelial passage of a low-molecular-weight molecule (inulin) on monolayers of bovine brain capillary ECs (BBCEC) was measured in response to parasites. Schistosomula induced a dramatic decrease in transendothelial permeability, a characteristic marker for the generation of an anti-inflammatory phenotype to ECs. This paracellular barrier enhancing effect on endothelial monolayers was due to a soluble substance(s) (below 1 kDa in size) secreted from S. mansoni schistosomula and not by mechanisms associated to adherence between parasites and ECs. The reinforcement of the endothelial barrier function was accompanied by an elevation of intracellular concentration of cyclic AMP (cAMP). The use of specific kinase inhibitors confirms that schistosomula activate ECs through a cAMP/protein kinase A pathway that leads to an increased phosphorylation of the myosin light-chain kinase. These combined findings suggest that the secretory/excretory products from schistosomula possess anti-inflammatory factor(s) that signal host microvascular endothelium. The immunological consequences of such activation are discussed

Targeting the Unfolded Protein Response as a Potential Therapeutic Strategy in Renal Carcinoma Cells Exposed to Cyclosporine A

International audienceBackground/Aim: Organ transplant patients treated with the immunosuppressive drug cyclosporine A often present malignant kidney tumors. Cyclosporine A can promote oncogenesis in a cell-intrinsic manner by increasing the production of vascular endothelial growth factor (VEGF). Materials and Methods: We explored the impact of cyclosporine A and the role of the unfolded protein response (UPR) on three human renal cell carcinoma (RCC) cell lines under normoxic and hypoxic (1% O-2) conditions. Resullt:Cyclosporine A regulated the expression of VEGF at the post-transcriptional level. Cyclosporine A induced the inositol requiring enzyme-1 alpha (IRE1 alpha) arm of the UPR and stabilized neosynthesized proteins in RCC cells. Toyocamycin, an inhibitor of IRE1 alpha, abolished the clonogenic growth of RCC cells and reduced induction of VEGF by cyclosporine A under hypoxia. Conclusion: Our findings highlight the impact of cyclosporine A on the proteostasis of RCC cells, and suggest the potential therapeutic interest of targeting the UPR against tumors arising in the context of organ transplantation

Impact of obesity on antiretroviral pharmacokinetics and immuno-virological response in HIV-infected patients: a case-control study : Obesity and antiretroviral pharmacokinetics

International audienceBackground: Obesity has a large prevalence among HIV-infected patients. Increased adipose tissue mass affects the pharmacokinetics of numerous drugs, but only a few data are available for antiretroviral drugs. Objective: In this study, we aimed to explore the pharmacokinetics of antiretroviral drugs and the immune-virological response in obese patients with HIV infection.Patients and methods: We examined data from 2009 to 2012 in our hospital’s database for HIV-1-infected patients who received an antiretroviral drug among abacavir, emtricitabine, lamivudine, tenofovir, efavirenz, etravirine, nevirapine, atazanavir/ritonavir, darunavir/ritonavir, lopinavir/ritonavir and raltegravir. Obese patients were defined with body mass index (BMI) ≥30 kg/m2 and normal-weight patients with BMI 19–25 kg/m2. Plasma concentrations (C12/24h) were compared for each antiretroviral using Mann-Whitney test. Suboptimal dosing and virological outcome were assessed by logistic regression, adjusting on covariates.Results: We enrolled 291 obese and 196 normal-weight patients. Among the 12 analyzed antiretroviral drugs, tenofovir, efavirenz and lopinavir C12h were significantly lower in obese than normal-weight patients: 66 versus 86 ng/mL, 1,498 versus 2,034 ng/mL and 4,595 versus 6,420 ng/mL respectively (P < 0.001). Antiretroviral C12/24h were more frequently below efficacy thresholds for obese than normal-weight patients after adjustment for other covariates (P < 0.001). Although obese patients showed higher CD4 count than normal-weight (510 vs 444 cells/µL, P < 0.001), the groups did not differ in virological failure rate.Conclusion: This study highlights the impact of obesity on antiretroviral plasma exposure, but identifies no consequence of this suboptimal exposure on the immuno-virological control in this population

Hepatitis C Virus Resistance to Carbohydrate-Binding Agents

International audienceCarbohydrate binding agents (CBAs), including natural lectins, are more and more considered as broad-spectrum antivirals. These molecules are able to directly inhibit many viruses such as Human Immunodeficiency Virus (HIV), Hepatitis C Virus (HCV), Dengue Virus, Ebola Virus or Severe Acute Respiratory Syndrome Coronavirus through binding to envelope protein N-glycans. In the case of HIV, it has been shown that CBAs select for mutant viruses with N-glycosylation site deletions which are more sensitive to neutralizing antibodies. In this study we aimed at evaluating the HCV resistance to CBAs in vitro. HCV was cultivated in the presence of increasing Galanthus nivalis agglutinin (GNA), Cyanovirin-N, Concanavalin-A or Griffithsin concentrations, during more than eight weeks. At the end of lectin exposure, the genome of the isolated strains was sequenced and several potential resistance mutations in the E1E2 envelope glycoproteins were identified. The effect of these mutations on viral fitness as well as on sensitivity to inhibition by lectins, soluble CD81 or the 3/11 neutralizing antibody was assessed. Surprisingly, none of these mutations, alone or in combination, conferred resistance to CBAs. In contrast, we observed that some mutants were more sensitive to 3/11 or CD81-LEL inhibition. Additionally, several mutations were identified in the Core and the non-structural proteins. Thus, our results suggest that in contrast to HIV, HCV resistance to CBAs is not directly conferred by mutations in the envelope protein genes but could occur through an indirect mechanism involving mutations in other viral proteins. Further investigations are needed to completely elucidate the underlying mechanisms

BK Polyomavirus Hijacks Extracellular Vesicles for En Bloc Transmission

International audienceMost people are asymptomatic carriers of the BK polyomavirus (BKPyV), but the mechanisms of persistence and immune evasion remain poorly understood. Furthermore, BKPyV is responsible for nephropathies in kidney transplant recipients. Unfortunately, the sole therapeutic option is to modulate immunosuppression, which increases the risk of transplant rejection. Using iodixanol density gradients, we observed that Vero and renal proximal tubular epithelial infected cells release two populations of infectious particles, one of which cosediments with extracellular vesicles (EVs). Electron microscopy confirmed that a single vesicle could traffic tens of viral particles. In contrast to naked virions, the EV-associated particles (eBKPyVs) were not able to agglutinate red blood cells and did not use cell surface sialylated glycans as an attachment factor, demonstrating that different entry pathways were involved for each type of infectious particle. However, we also observed that naked BKPyV and eBKPyV were equally sensitive to neutralization by the serum of a seropositive patient or commercially available polyvalent immunoglobulin preparations, which occurred at a postattachment step, after endocytosis. In conclusion, our work shows a new mechanism that likely plays a critical role during the primary infection and in the persistence, but also the reactivation, of BKPyV. IMPORTANCE Reactivation of BKPyV is responsible for nephropathies in kidney transplant recipients, which frequently lead to graft loss. The mechanisms of persistence and immune evasion used by this virus remain poorly understood, and a therapeutic option for transplant patients is still lacking. Here, we show that BKPyV can be released into EVs, enabling viral particles to infect cells using an alternative entry pathway. This provides a new view of BKPyV pathogenesis. Even though we did not find any decreased sensitivity to neutralizing antibodies when comparing EV-associated particles and naked virions, our study also raises important questions about developing prevention strategies based on the induction or administration of neutralizing antibodies. Deciphering this new release pathway could enable the identification of therapeutic targets to prevent BKPyV nephropathies. It could also lead to a better understanding of the pathophysiology of other polyomaviruses that are associated with human diseases

Polyphenols Inhibit Hepatitis C Virus Entry by a New Mechanism of Action

Despite the validation of direct-acting antivirals for hepatitis C treatment, the discovery of new compounds with different modes of action may still be of importance for the treatment of special patient populations. We recently identified a natural molecule, epigallocatechin-3-gallate (EGCG), as an inhibitor of hepatitis C virus (HCV) targeting the viral particle. The aim of this work was to discover new natural compounds with higher anti-HCV activity than that of EGCG and determine their mode of action. Eight natural molecules with structure similarity to EGCG were selected. HCV JFH1 in cell culture and HCV pseudoparticle systems were used to determine the antiviral activity and mechanism of action of the compounds. We identified delphinidin, a polyphenol belonging to the anthocyanidin family, as a new inhibitor of HCV entry. Delphinidin inhibits HCV entry in a pangenotypic manner by acting directly on the viral particle and impairing its attachment to the cell surface. Importantly, it is also active against HCV in primary human hepatocytes, with no apparent cytotoxicity and in combination with interferon and boceprevir in cell culture. Different approaches showed that neither aggregation nor destruction of the particle occurred. Cryo-transmission electron microscopy observations of HCV pseudoparticles treated with delphinidin or EGCG showed a bulge on particles that was not observed under control conditions. In conclusion, EGCG and delphinidin inhibit HCV entry by a new mechanism, i.e., alteration of the viral particle structure that impairs its attachment to the cell surface. IMPORTANCE In this article, we identify a new inhibitor of hepatitis C virus (HCV) infection, delphinidin, that prevents HCV entry. This natural compound, a plant pigment responsible for the blue-purple color of flowers and berries, belongs to the flavonoid family, like the catechin EGCG, the major component present in green tea extract, which is also an inhibitor of HCV entry. We studied the mode of action of these two compounds against HCV and demonstrated that they both act directly on the virus, inducing a bulging of the viral envelope. This deformation might be responsible for the observed inhibition of virus attachment to the cell surface. The discovery of such HCV inhibitors with an unusual mode of action is important to better characterize the mechanism of HCV entry into hepatocytes and to help develop a new class of HCV entry inhibitors