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.

Silibinin A and silibinin B, as well as Legalon SIL, inhibit HCV replicon and JFH1 replication in cell culture. This effect is at least partly explained by the ability of these compounds to inhibit HCV RNA-dependent RNA polymerase activity. Our results provide a basis for the optimization and subsequent development of members of the Flavonoid family as specific HCV antivirals.

B cell activating factor (BAFF) plays a key role in promoting B lymphocyte activation. We investigated whether danger signals induce BAFF secretion by cultured salivary gland epithelial cells (SGEC), which are the target of primary Sjögren's syndrome, a prototypic systemic autoimmune disease. SGEC cultures were established from minor salivary glands obtained from ten patients with pSS or sicca symptoms. BAFF mRNA and protein were measured after stimulation of the different Toll-like receptors (TLR) by agonists or viruses. The expression of TLR2, -3, and -7 was detected in SGEC. Poly (I:C) (a synthetic TLR3 agonist) and reovirus-1 (a dsRNA virus) induced high expression of BAFF mRNA (multiplied by a factor of 246 AE 39 (SEM) and 347 AE 66, respectively) and of BAFF protein secretion (58.49 AE 4.34 pg/mL and 69.73 AE 5.67). Inhibition of both the endosomal (by chloroquine) and IFN (by anti-IFNAR antibody) pathways partly inhibited BAFF expression. Treatment with both dsRNA virus and poly (I:C) induced high levels of BAFF mRNA and protein expression by SGEC, through pathways dependent on and independent of TLR and dependent on and independent of IFN. BAFF induction by target organs of autoimmune diseases after viral infection may be a link between innate immunity and autoimmunity.

Hepatitis C virus (HCV) has been classified into six clades as

Lamivudine was the first approved inhibitor of hepatitis B virus (HBV) reverse transcriptase (RT). Lamivudine resistance develops in 53% to 76% of patients after 3 years of treatment. We extensively characterized the dynamics of HBV quasispecies variant populations in four HBV-infected patients who developed lamivudine resistance. Virological breakthrough was preceded by 2 to 4 months by the emergence of quasispecies variants bearing amino acid substitutions at RT position 204, i.e., within the YMDD catalytic motif (rtM204V/ I). Three patients had a gradual switch from a YMDD variant population at baseline to a 100% lamivudineresistant variant population, whereas the remaining patient had a fluctuating pattern of resistance variant dynamics. Careful analysis of amino acid substitutions located outside domain C of HBV RT, including those known to partially restore replication capacities in vitro, showed that the in vivo replication of HBV variants is driven by multiple forces, including intrinsic replicative advantages conferred by mutations accumulating outside domain C and the changing environment in which these variants replicate. Our findings also suggest that individual treatment optimization will require sensitive methods capable of detecting the emergence of viral resistance before the relevant variants acquire optimal replicative capacities. Hepatitis B virus (HBV) infection is a major public health problem, with approximately 350 million individuals chronically infected worldwide (19). Chronic HBV carriers are exposed to a risk of complications, such as chronic hepatitis, cirrhosis, and hepatocellular carcinoma, of which HBV is currently the most frequent cause (13). Up to one million people die every year from complications of HBV infection (19).HBV infection is characterized by high levels of virus production and turnover (28, 39), whereas the HBV reverse transcriptase (RT), like the human immunodeficiency virus (HIV) RT, is an error-prone enzyme lacking 3Ј-5Ј-exonuclease proofreading capacity (3,14). As a result, HBV, like other viruses with error-prone polymerases, such as HIV, hepatitis C virus, and poliovirus, has a quasispecies distribution in infected individuals (14). This means that HBV circulates as a complex mixture of genetically distinct but closely related variants that are in equilibrium at a given time point of infection in a given replicative environment. The quasispecies distribution of HBV implies that any newly generated mutation conferring a selective advantage to the virus in a given replicative environment will allow the corresponding viral population to overtake the other variants, following a classical Darwinian evolutionary process (10).Treatment of chronic hepatitis B is aimed at driving viral replication to the lowest possible level, and thereby to halt the progression of liver disease and prevent the onset of complications. However, HBV infection cannot be fully eradicated, because of covalently closed circular proviral DNA persistence in host cells. The first HBV RT inhibit...

We have identified naturally occurring 2-benzylidenebenzofuran-3-ones (aurones) as new templates for non-nucleoside hepatitis C virus (HCV) RNA-dependent RNA polymerase (RdRp) inhibitors. The aurone target site, identified by site-directed mutagenesis, is located in thumb pocket I of HCV RdRp. The RdRp inhibitory activity of 42 aurones was rationally explored in an enzyme assay. Molecular docking studies were used to determine how aurones bind to HCV RdRp and to predict their range of inhibitory activity. Seven aurone derivatives were found to have potent inhibitory effects on HCV RdRp, with IC(50) below 5 μM and excellent selectivity index (inhibition activity versus cellular cytotoxicity). The most active aurone analogue was (Z)-2-((1-butyl-1H-indol-3-yl)methylene)-4,6-dihydroxybenzofuran-3(2H)-one (compound 51), with an IC(50) of 2.2 μM. Their potent RdRp inhibitory activity and their low toxicity make these molecules attractive candidates as direct-acting anti-HCV agents.

BackgroundIn HIV-infected patients on long-term HAART, virus persistence in resting long-lived CD4 T cells is a major barrier to curing the infection. Cell quiescence, by favouring HIV latency, reduces the risk of recognition and cell destruction by cytotoxic lymphocytes. Several cell-activation-based approaches have been proposed to disrupt cell quiescence and then virus latency, but these approaches have not eradicated the virus. CD4+CD25+ regulatory T cells (Tregs) are a CD4+ T-cell subset with particular activation properties. We investigated the role of these cells in virus persistence in patients on long-term HAART.Methodology/Principal FindingsWe found evidence of infection of resting Tregs (HLADR−CD69−CD25hiFoxP3+CD4+ T cells) purified from patients on prolonged HAART. HIV DNA harbouring cells appear more abundant in the Treg subset than in non-Tregs. The half-life of the Treg reservoir was estimated at 20 months. Since Tregs from patients on prolonged HAART showed hyporesponsiveness to cell activation and inhibition of HIV-specific cytotoxic T lymphocyte-related functions upon activation, therapeutics targeting cell quiescence to induce virus expression may not be appropriate for purging the Treg reservoir.ConclusionsOur results identify Tregs as a particular compartment within the latent reservoir that may require a specific approach for its purging.

Genotypic algorithms for prediction of HIV-1 coreceptor usage need to be evaluated in a clinical setting. We aimed at studying (i) the correlation of genotypic prediction of coreceptor use in comparison with a phenotypic assay and (ii) the relationship between genotypic prediction of coreceptor use at baseline and the virological response (VR) to a therapy including maraviroc (MVC). Antiretroviral-experienced patients were included in the MVC Expanded Access Program if they had an R5 screening result with Trofile (Monogram Biosciences). V3 loop sequences were determined at screening, and coreceptor use was predicted using 13 genotypic algorithms or combinations of algorithms. Genotypic predictions were compared to Trofile; dual or mixed (D/M) variants were considered as X4 variants. Both genotypic and phenotypic results were obtained for 189 patients at screening, with 54 isolates scored as X4 or D/M and 135 scored as R5 with Trofile. The highest sensitivity (59.3%) for detection of X4 was obtained with the Geno2pheno algorithm, with a false-positive rate set up at 10% (Geno2pheno10). In the 112 patients receiving MVC, a plasma viral RNA load of <50 copies/ml was obtained in 68% of cases at month 6. In multivariate analysis, the prediction of the X4 genotype at baseline with the Geno2pheno10 algorithm including baseline viral load and CD4 nadir was independently associated with a worse VR at months 1 and 3. The baseline weighted genotypic sensitivity score was associated with VR at month 6. There were strong arguments in favor of using genotypic coreceptor use assays for determining which patients would respond to CCR5 antagonist.During the entry process of HIV-1 in the target cell, the interaction of the viral surface glycoprotein gp120 with a cellular chemokine receptor, the coreceptor, is an essential step, besides attachment to the CD4 receptor, and precedes the fusion of the viral envelope to the cell membrane. The V3 hypervariable loop of gp120 is involved in coreceptor binding. Two coreceptors are most commonly used in vivo: CCR5 and CXCR4 (1). Viral coreceptor use (i.e., usage of either CCR5 or CXCR4) differs between viral isolates. If CCR5-using isolates (R5 isolates) are by far predominant at the early stage of early infection and seem to be selected during HIV-1 transmission, CXCR4 usage (X4 tropism) will become more prevalent as the infection progresses, with approximately half of X4 or dual or mixed (D/M) tropism in antiretroviral-experienced patients with advanced HIV-1 disease (10).Maraviroc (MVC), a CCR5 inhibitor, binds specifically to CCR5 and blocks HIV-1 binding to this coreceptor (5). MVC has shown a potent antiviral effect in antiretroviral-experienced patients with R5 HIV-1 infection in a placebo-controlled trial (7) and is currently prescribed in this indication. As MVC has shown little activity in patients with X4 viruses, the determination of HIV-1 coreceptor use has become mandatory before the prescription of CCR5 inhibitors (8).