ACE2 is a mutual entry factor for HCV and SARS-COV-2
2The Laboratory of Structural Biology of Infectious Diseases, The Azreli Faculty of Medicine - Bar Ilan-University, Israel
SARS-CoV-2 enter its host cell via its interaction with the cellular receptor ACE2. Hepatocytes, the target cells of hepatitis C virus infection, express low level of ACE2. Recently, we have demonstrated that SARS-CoV-2 and HCV coinfect and co-replicate in hepatocytes. Moreover, we reported the enhanced SARS-CoV-2 entry into HCV-pre-infected hepatocytes via increase in ACE2 expression in HCV-infected cells. Here we aimed to evaluate whether ACE2 plays a role in HCV life cycle as well.
We demonstrate that Huh7.5 cells overexpressing ACE2 were more susceptible to HCV infection, while ACE2 silencing in Huh7.5 cells resulted in decreased susceptibility to HCV infection. We investigated which step in the HCV life cycle is influenced by ACE2 and identified that ACE2 overexpression in Huh7.5 cells increased HCVpp uptake and HCV cell binding as compared to control Huh7.5 cells. In contrast, RNA levels were similar in replicon cells with versus without ACE2 overexpression. These observations show that ACE2 increases viral entry into Huh7.5 cells at the cell binding step, without affecting HCV RNA replication. Furthermore, we demonstrate higher binding of HCV envelope protein E2 to ACE2-expressing Huh7.5 cells compared to control Huh7.5 cells, and also a direct ACE2-E2 binding in vitro assays, providing evidence for the involvement of ACE2 in HCV entry.
This study reveals that ACE2 is a novel entry factor for HCV, which is upregulated in response to HCV infection. The HCV-induced increased ACE2 expression results in enhanced HCV and SARS-CoV-2 infections and efficient coinfection of both viruses in hepatocytes.