Host-interferon-stimulated gene response to virus-host recombinant variants of hepatitis E virus and enhanced viral replication.

Abstract

The hepatitis E virus (HEV) is a leading cause of acute hepatitis worldwide. HEV infection can become chronic in immunocompromised individuals, in whom virus-host recombinant variants (VHRVs) can be detected. These variants often harbor host-derived insertions in the polyproline-rich region (PPR), and most display enhanced replication in vitro. However, the mechanisms underlying this replicative advantage remain unclear. It is likely that genes of the infected cells are differentially expressed according to the replicative capacity of the strain. The host factors involved in the improvement of the replicative capacity of these VHRVs are yet to be identified.In this study, we analyzed the host transcriptional response to seven VHRVs in HepG2/C3A cells using bulk RNA sequencing at 48 h and 168 h post-infection. Five VHRVs (RNF19A, ZNF787, KIF1B, RPS17, EEF1A1) previously associated with a high replication rate induced more significant, distinct transcriptomic changes than low-replicative variants (RNA18, RPL6), particularly at 168 h. A shared set of 25 genes, especially interferon-stimulated genes (ISGs), was upregulated in cells infected with high-replicating variants. Interestingly, ISG induction was limited at 48 h despite high viral RNA concentrations, suggesting a delayed antiviral response. At 168 h, high ISG expression coincided with high viral loads, indicating that VHRVs may evade or exploit immune defenses. Our findings reveal candidate ISGs such as IFIT1 and ISG15 that may influence HEV persistence and immune escape. These results offer new insights into the interplay between VHRV replication and host immunity.IMPORTANCEHepatitis E virus (HEV) is a major cause of acute hepatitis and can cause chronic infections in immunocompromised individuals. Virus-host recombinant variants (VHRVs) having integrated host-derived insertions often replicate more effectively, yet the host determinants of this phenotype remain unclear. With RNA sequencing of HepG2/C3A-infected cells, we observed that high-replicating VHRVs induce a delayed but strong expression of interferon-stimulated genes (ISGs), including IFIT1 and ISG15, despite high viral loads. These results suggest that VHRVs may transiently modulate or evade aspects of host antiviral defenses. Our study revealed host transcriptional patterns associated with enhanced viral replication, providing insight into potential mechanisms that enhance HEV replication and highlighting candidate pathways that could influence the interplay between viral replication and immune responses, all requiring further investigation.