Interplay of Amino Acid Residues at Positions 28 and 31 in NS5A Defines Resistance Pathways in HCV GT2

Prevalence and drug resistance analysis of hepatitis C virus genotypes in Heilongjiang, China

Hepatitis C still poses a threat to public safety, and there are few reports of hepatitis C virus (HCV) in Heilongjiang Province. Therefore, we aimed to study the epidemiology and resistance-associated substitutions (RASs) of HCV in Heilongjiang and explore the efficacy of treatment. 7019 specimens from Heilongjiang Province were subjected to the genotype identification. The Autoregressive Integrated Moving Average (ARIMA) model was utilized to predict HCV infection trends from 2024 to 2030. The Sanger sequencing was performed on samples of genotype(GT) 1b and 2a to investigate RASs. Phylogenetic analysis was conducted to assess the similarity of local HCV sequences with those from other countries. In addition, we tracked the effect of patients treated with DAAs and the relationship between efficacy and RASs. The predominant HCV subtypes in Heilongjiang were 1b (47.51 %) and 2a (43.85 %). From 2012 to 2023, the proportions of GT2a, GT3a, GT3b, and GT6a gradually increased. And the prevalence of GT2a will exceed that of GT1b over the next seven years. The proportion of RASs in GT1b and GT2a NS5A region was 73.47 % and 15.22 %, respectively. And the proportion of RASs in GT1b NS5B region was 100 %. Local HCV sequences exhibited phylogenetic relationships with sequences from other countries. The GT1b R30Q and GT2a C92S were correlated with drug efficacy. K107R and P206S, which have not been reported in the literature, were also related to drug efficacy. The epidemiology of HCV genotypes in Heilongjiang is becoming increasingly diverse. HCV GT1b has a large variety and a high proportion of RASs, and patients infected with this genotype of HCV need to be sequenced before treatment.

Synthesis of Indole-Fused Six-, Seven-, or Eight-Membered N,O-Heterocycles via Rhodium-Catalyzed NH-Indole-Directed C-H Acetoxylation/Hydrolysis/Annulation

We report herein the facile synthesis of indole-fused six-, seven-, or eight-membered N,O-heterocycles through rhodium-catalyzed C-H acetoxylation/hydrolysis/annulation. The notable features of this method include C-H acetoxylation using NH-indole as the intrinsic directing group, high functional group compatibility, and construction of indole-fused medium-sized rings.

Cell Culture Studies of the Efficacy and Barrier to Resistance of Sofosbuvir-Velpatasvir and Glecaprevir-Pibrentasvir against Hepatitis C Virus Genotypes 2a, 2b, and 2c

The introduction of highly efficient therapies with direct-acting antivirals (DAA) for patients with chronic hepatitis C virus (HCV) infection offers exceptional opportunities to globally control this deadly disease. For achieving this ambitious goal, it is essential to prevent antiviral resistance against the most optimal first-line and retreatment DAA choices. We performed independent comparisons of the efficacy and barrier to resistance of pangenotypic DAA regimens for HCV genotype 2 infections, using previously and newly developed efficient cell culture-adapted strains of subtypes 2a, 2b, and 2c. With the applied experimental cell culture conditions, combination treatment with the sofosbuvir-velpatasvir or glecaprevir-pibrentasvir DAA regimen was efficient in eradicating HCV infections; in contrast, single-drug treatments frequently led to viral escape. Sequence analysis of drug targets from recovered viruses revealed known resistance-associated substitutions (RAS) emerging in the NS3 protease or NS5A after treatment failure. These RAS were genetically stable after viral passage, and viruses with these RAS exhibited significant phenotypic resistance. After sofosbuvir treatment failure, only a genotype 2a virus harbored NS5B RAS S282T and thus had decreased susceptibility to nucleotide analogs (nucs). However, in most cases, viral escape from sofosbuvir led to other NS5B substitutions but drug susceptibility was maintained, and in one case, no changes in NS5B were detected. For a genotype 2b virus, after treatment failure with sofosbuvir-velpatasvir, the efficacy of retreatment with glecaprevir-pibrentasvir was maintained due to the high barrier to resistance and low cross-resistance of pibrentasvir. Our findings suggest the slight superiority of glecaprevir-pibrentasvir against genotype 2b in culture, which could have potential therapeutic interest meriting more definitive investigations in the clinic.