The novel HBx mutation F30V correlates with hepatocellular carcinoma in vivo, reduces hepatitis B virus replicative efficiency and enhances anti-apoptotic activity of HBx N terminus in vitro.

OBJECTIVE: We aimed to investigate HBx genetic elements correlated with hepatitis B virus (HBV) -related hepatocellular carcinoma (HCC) and their impact on (a) HBV replicative efficiency, (b) HBx binding to circular covalently closed DNA (cccDNA), (c) apoptosis and cell-cycle progression, and (d) HBx structural stability. METHODS: This study included 123 individuals chronically infected with HBV: 27 with HCC (77.9% (21/27) genotype D; 22.1% (6/27) genotype A) and 96 without HCC (75% (72/96) genotype D; 25.0% (24/96) genotype A). HepG2 cells were transfected by wild-type or mutated linear HBV genome to assess pre-genomic RNA (pgRNA) and core-associated HBV-DNA levels, HBx-binding onto cccDNA by chromatin immunoprecipitation-based quantitative assay, and rate of apoptosis and cell-cycle progression by cytofluorimetry. RESULTS: F30V was the only HBx mutation correlated with HCC (18.5% (5/27) in HCC patients versus 1.0% (1/96) in non-HCC patients, p 0.002); a result confirmed by multivariate analysis. In vitro, F30V determined a 40% and 60% reduction in pgRNA and core-associated HBV-DNA compared with wild-type (p <0.05), in parallel with a significant decrease of HBx binding to cccDNA and decreased HBx stability. F30V also decreased the percentage of apoptotic cells compared with wild-type (14.8 ± 6.8% versus 19.1 ± 10.1%, p <0.01, without affecting cell-cycle progression) and increased the probability of HBx-Ser-31 being phosphorylated by PI3K-Akt kinase (known to promote anti-apoptotic activity). CONCLUSIONS: F30V was closely correlated with HBV-induced HCC in vivo, reduced HBV replicative efficiency by affecting HBx-binding to cccDNA and increased anti-apoptotic HBx activity in vitro. This suggests that F30V (although hampering HBV's replicative capacity) may promote hepatocyte survival, so potentially allowing persistent production of viral progeny and initiating HBV-driven hepatocarcinogenesis. Investigation of viral genetic markers associated with HCC is crucial to identify those patients at higher risk of HCC, who hence deserve intensive liver monitoring and/or early anti-HBV therapy.

Effect of maraviroc on non-R5 tropic HIV-1: refined analysis of subjects from the phase IIb study A4001029.

We characterized maraviroc susceptibility of dual/mixed tropic viruses from subjects enrolled onto phase IIb study A4001029. Maraviroc baseline plasma samples from 13 multidrug-experienced subjects were sequenced and the HIV-1-env gene cloned into pNL4.3Δenv to obtain recombinant viruses. The V3 region was sequenced by the Sanger method and ultradeep sequencing. By analysing subjects having a weighted optimized background therapy susceptibility (wOBT) score of <1, 3/7 subjects were characterized by good in vivo and in vitro response to maraviroc therapy. Molecular docking simulations allowed us to rationalize the maraviroc susceptibility of dual/mixed tropic viruses. A subset of subjects with dual/mixed tropic viruses responded to maraviroc. Further investigations are warranted of CCR5 antagonists in subjects carrying dual/mixed tropic virus that explore the feasible use of maraviroc in subjects that is potentially larger than those infected with a pure R5 virus.

NeuroAIDS: virological aspects of HIV infection.

NeuroAIDS is one of the main complications of chronic HIV-infection. The Central Nervous System is an immunologic sanctuary for HIV and allows the persistence of the virus despite an efficient antiretroviral therapy. HIV-1 could promote the neurodegeneration through the induction of inflammation by the release of neurotoxins from infected cells. In addition, several viral proteins can directly contribute to the neuronal damages, activate cell-signaling involved in the control of cellular survival and apoptosis, favoring functional alterations in the target cells. Macrophages play a key role in the pathogenesis of NeuroAIDS, they are the main reservoirs of the infection in brain, promoting the inflammatory escalation, astrogliosis and degeneration process. This review aims to highlight the virological aspects associated with NeuroAIDS including pathogenesis, and treatment of HIV-1 in the CNS sanctuaries.

The lowest X4 Geno2Pheno false-positive rate is associated with greater CD4 depletion in HIV-1 infected patients.

Through this study we evaluated whether the HIV-1 tropism determined by genotypic analysis correlates with HIV-1 markers, such as CD4 cell count and plasma HIV-RNA. The analysis was performed on 1221 HIV-1 B-subtype infected patients with an available V3 sequence (all maraviroc naive). Of them, 532 were antiretroviral therapy (ART) naive and 689 ART experienced. Tropism determination was performed by using the geno2pheno (co-receptor) algorithm set at a false-positive rate (FPR) of 10% and 2%. Potential associations of FPR with CD4 cell count and viraemia were evaluated. Association of V3 mutations with genotypic-determined tropism was also evaluated according to different FPR ranges. About 26% of patients (either ART naive or ART experienced) were infected by X4-tropic viruses (using the classical 10% FPR cut-off). However, a significantly lower proportion of ART-naive patients had FPR ≤ 2% in comparison with ART-experienced patients (4.9% vs. 12.6%, respectively, p <0.001). The risk of advanced HIV-1 infection (with CD4 cell count ≤ 200 cells/mm(3)) was significantly greater in X4-infected patients, either ART-naive (OR (95% CI)), 4.2 (1.8-9.2); p 0.0006) or ART-experienced (2.3 (1.4-3.6); p 0.0003), with FPR set at 2% (but not at 10%). This finding was confirmed by multivariable logistic analysis. No relationship was found between viraemia and FPR ≤2%. Some X4-related mutations were significantly associated with FPR ≤2% (ART-naive patients, S11R, Y21V, G24K and G24R, p ≤0.001; ART-experienced patients, Y7K, S11R, H13Y, p ≤0.002). In conclusion, these findings show that within the context of genotypically-assessed CXCR4 tropism, FPR ≤2% defines (far better than 10%-FPR) a viral population associated with low CD4 rank, with potentially greater cytopathic effect, and with more advanced disease.