Resistance-associated substitution and ledipasvir/sofosbuvir therapy in Mongolian chronic hepatitis C patients.

BACKGROUND: Mongolia has the highest prevalence of hepatitis C virus (HCV) infection worldwide. Ledipasvir/sofosbuvir (LDV/SOF) was introduced to Mongolia since 2016 for HCV eradication. It has been reported that HCV resistance-associated substitutions (RASs) would affect the effectiveness of LDV/SOF in western chronic hepatitis C (CHC) patients. We thus investigated the effectiveness of LDV/SOF and the impact of RAS on the treatment outcome in Mongolian CHC patients. METHODS: Patients with genotype (GT) 1b HCV infection were prospectively enrolled in Mongolia and treated with LDV/SOF for 12 weeks. The proportion of pre-treatment NS5A Y93H RAS in viral quasispecies was measured with next-generation sequencing. The endpoint of LDV/SOF effectiveness was sustained virological response at post-treatment week 12 (SVR12). RESULTS: A total of 94 CHC patients were evaluated. The baseline Y93H proportion was <1% in 74 patients, 1-15% in 7, 15-50% in 2, and ≥50% in 11. All patients completed 12-week LDV/SOF treatment and the SVR rate was 90.4%. The rate of failure to achieve SVR12 for patients with Y93H < 1%, 1-15%, and ≥15% were 0%, 14.3%, and 61.5%, respectively (p for trend = 0.001). In univariable analysis, older age, baseline alanine transaminase level <40 U/mL, and a higher proportion of Y93H were associated with treatment failure. In multivariable analysis, only a higher proportion of Y93H was associated with treatment failure (p = 0.022). CONCLUSION: LDV/SOF therapy achieves a high SVR rate in Mongolian CHC GT1b patients without baseline Y93H RAS. A higher proportion of Y93H may severely undermine the effectiveness of LDV/SOF.

Pegylated IFN-α suppresses hepatitis C virus by promoting the DAPK-mTOR pathway.

Death-associated protein kinase (DAPK) has been found to be induced by IFN, but its antiviral activity remains elusive. Therefore, we investigated whether DAPK plays a role in the pegylated IFN-α (peg-IFN-α)-induced antiviral activity against hepatitis C virus (HCV) replication. Primary human hepatocytes, Huh-7, and infectious HCV cell culture were used to study the relationship between peg-IFN-α and the DAPK-mammalian target of rapamycin (mTOR) pathways. The activation of DAPK and signaling pathways were determined using immunoblotting. By silencing DAPK and mTOR, we further assessed the role of DAPK and mTOR in the peg-IFN-α-induced suppression of HCV replication. Peg-IFN-α up-regulated the expression of DAPK and mTOR, which was associated with the suppression of HCV replication. Overexpression of DAPK enhanced mTOR expression and then inhibited HCV replication. In addition, knockdown of DAPK reduced the expression of mTOR in peg-IFN-α-treated cells, whereas silencing of mTOR had no effect on DAPK expression, suggesting mTOR may be a downstream effector of DAPK. More importantly, knockdown of DAPK or mTOR significantly mitigated the inhibitory effects of peg-IFN-α on HCV replication. In conclusion, our data suggest that the DAPK-mTOR pathway is critical for anti-HCV effects of peg-IFN-α.