Comparison of replication competence of wild-type and lamivudine-resistant hepatitis B virus isolates from a chronic hepatitis B patient

Investigation of multidrug-resistance mutations of hepatitis B virus (HBV) in a large cohort of chronic HBV-infected patients with treatment of nucleoside/nucleotide analogs

Multidrug-resistance hepatitis B virus (MDR HBV), defined as those with mutations resistant to both nucleoside analogs lamivudine/telbivudine/entecavir (LAM/LdT/ETV) and nucleotide analog adefovir (ADV), has potential to cause treatment difficulty. To clarify clinical prevalence and virological features of MDR HBV, we investigated serum samples from 28,236 chronic HBV-infected patients with treatment of nucleoside/nucleotide analogs. All patients underwent resistance testing in the Fifth Medical Center of Chinese PLA General Hospital between 2007 and 2019. MDR mutations were screened by direct sequencing; MDR strains (with mutations co-located on the same viral genome) were verified by clonal sequencing (≥20 clones/sample) and subjected to phenotypic analysis if necessary. MDR mutations were detected in 0.81% (229/28,236) patients. MDR strains were verified in 83.0% (190/229) of MDR mutation-positive patients. As ETV-resistance mutation (ETVr) had additional mutation(s) on LAMr conferring more resistance, MDR mutations fell into LAMr + ADVr and ETVr + ADVr subsets. Sixteen mutation patterns of MDR strains were verified, including eight with LAMr + ADVr and eight with ETVr + ADVr. Refractory to sequential therapies of LAM/LdT/ETV and ADV were closely linked with MDR HBV development. Ten representative MDR strains (five LAMr + ADVr and five ETVr + ADVr) tested all had decrease in replication capacity compared to wild-type strains and decrease extent was positively related with the number of primary resistance on viral genome. Compared to ADV + ETV, TDF/TDF + ETV showed higher inhibitory rates on MDR HBV, especially for the five ETVr + ADVr strains (74.5%-97.6% vs. 60.2%-79.5%, all P < 0.05). This study significantly extends the knowledge on MDR HBV and has clinical implications for resistance management.

The MOV10 helicase restricts hepatitis B virus replication by inhibiting viral reverse transcription

Interferons inhibit viruses by inducing antiviral protein expression. One of the interferon-induced antiviral proteins, human Moloney leukemia virus 10 (MOV10), a superfamily 1 RNA helicase, has been shown to inhibit retroviruses and several RNA viruses. However, it remains undetermined whether MOV10 also inhibits DNA viruses, including hepatitis B virus (HBV). Here, we report that MOV10 dramatically reduces the levels of intracellular HBV DNA, resulting in significant inhibition of both the HBV experimental strain and the clinical isolates. Mechanistic experiments revealed that MOV10 interacts with HBV RNA and blocks the early step of viral reverse transcription, thereby impairing viral DNA synthesis, without affecting viral gene expression and pregenomic RNA encapsidation. Moreover, mutation of the helicase domain of MOV10 caused loss of binding to HBV RNA and of the anti-HBV activity. Together, our results indicate that MOV10 restricts HBV replication, insights that may open new avenues to the development of anti-HBV therapeutics.

Investigation of hepatitis B virus (HBV) rtS78T/sC69* mutation in a large cohort of chronic HBV-infected patients with nucleoside/nucleotide analogue treatment

This study aimed to investigate clinical occurrence and significance of the rtS78T/sC69* mutation of hepatitis B virus (HBV). A total of 22,009 consecutive chronic HBV-infected patients who underwent resistance testing at the Fifth Medical Center of Chinese PLA General Hospital (Original name Beijing 302 Hospital) from 2007 to 2016 were enrolled. Serum samples were collected for sequence analysis of HBV reverse-transcriptase (RT) and S regions. Phenotypic analysis was performed to evaluate the viral replication capacity and drug susceptibility. The rtS78T mutation was detected in 0.83% (182/22,009) of the patients' samples. All mutations simultaneously created a stop codon at sC69 (sC69*). The prevalence of rtS78T/sC69* did not differ significantly between the patients with and without entecavir/tenofovir treatment. Of the 182 mutation-positive samples, 41 (22.5%) were detected with signature drug-resistance mutations to adefovir (n = 26), lamivudine (n = 11), entecavir (n = 3), and lamivudine plus adefovir (n = 1). The HBV DNA and RNA levels of the rtS78T/sC69* mutant were significantly increased compared to the wild-type; while the mutant had undetectable secreted and intracellular HBsAg, and its half maximal effective concentration to lamivudine, adefovir, entecavir, and tenofovir were 3.73-, 1.61-, 4.76-, and 3.71-fold of the wild-type, respectively. Artificial elimination of the rtS78T mutation had a limited effect on the drug susceptibilities. The data obtained in the present study suggested that the emergence of the rtS78T/sC69* mutation was not closely related to entecavir/tenofovir treatment and itself appeared insufficient to confer drug resistance unless it coexisted with signature drug-resistance mutations.

A peptide-based inhibitor of gp96 suppresses HBsAg expression and HBV replication by upregulation of p53

In hepatitis B virus (HBV) infection, the virus produces redundant hepatitis B surface antigen (HBsAg) that plays a key role in driving T-cell tolerance and viral persistence. However, currently available anti-HBV agents have no direct effect on HBsAg transcription and protein expression. In this study, we designed a heat shock protein gp96 inhibitor p37 with the cell penetrating peptide PTD (protein transduction domain of trans-activator of transcription), which mediated p37 internalization into hepatocytes. PTD-p37 effectively suppressed HBsAg expression and viral replication both in vitro and in vivo. We further provide evidence that PTD-p37 suppressed HBV enhancer/promoter activity via p53 upregulation. Moreover, PTD-p37 had antiviral activity against a lamivudine-resistant HBV strain. Considering that suppression of HBsAg expression is a major goal for treatment of HBV infection, our results provide a basis for developing a new therapeutic approaches targeting host factors against viral expression.

Prevalence of the entecavir-resistance-inducing mutation rtA186T in a large cohort of Chinese hepatitis B virus patients

This study aimed to clarify whether rtA186T and rtI163V substitutions of hepatitis B virus (HBV) contributed to entecavir (ETV) resistance. A total of 22,009 Chinese patients with chronic HBV infection who received resistance testing at Beijing 302 Hospital from 2007 to 2016 were enrolled. Among them, 6170 patients had been treated with ETV. The HBV reverse transcriptase gene was screened by direct sequencing and verified by clonal sequencing. Phenotypic analysis was performed for evaluating replication capacity and drug susceptibility. Classical ETV-resistance mutations rtT184/S202/M250substitution+rtM204V/I±L180M (LAM-r), rtA186T, and rtI163V were detected in 1252 (5.69%), 14 (0.06%), and 230 (1.05%) of the 22,009 patients, respectively. The rtA186T mutation always coexisted with LAM-r, but not with rtI163V. The 14 rtA186T-positive patients were all treated with LAM and ETV, and the emergence of the rtA186T+LAM-r was closely associated with virological breakthrough or inadequate virological response to ETV. By contrast, the emergence of rtI163V was not related to ETV treatment. Six rtA186T-positive patients were followed up longitudinally, showing that these patients all had received sequential adefovir and LAM monotherapies prior to ETV treatment. Compared to wild-type strain, two patient-derived mutants' rtL180M+A186T+M204V and rtL180M+T184S+A186T+M204V had 86.7% and 89.2% decreased replication capacity, 210- and 555-fold increased ETV resistance, respectively; and artificial elimination of rtA186T largely restored their ETV sensitivity. The rtA186T mutants remained sensitive to tenofovir. In conclusion, our study confirmed that rtA186T plus LAM-r is a novel ETV-resistance mutation pattern which conferred ETV resistance in multiple Chinese patients.