A CRISPR-based genome-wide loss-of-function screen defines a role of host metabolism in regulating hepatitis B virus infection.

Hepatitis B virus (HBV) co-opts and interacts with an extensive array of host factors for productive infection. Herein, we develop an HBV reporter virus expressing red fluorescent protein (HBV-RFP) that is suitable for a CRISPR-based genome-wide screen for HBV host dependency factors. HepG2NTCP/Cas9 cells were transduced with a pooled lentiviral library of single-guide RNA (sgRNA) targeting 19,114 human genes, edited and infected with HBV-RFP. RFP-low cells were sorted using fluorescence-activated cell sorting. The sorted cells were expanded and underwent two additional rounds of infection and sorting to enrich for sgRNA-targeted proviral host factors. By next-generation sequencing and bioinformatic analyses, we identified 63 genes as candidate host proviral factors, including known HBV proviral factors: RXRA, POLL, LDLR, and NTCP. Among the novel candidate genes, knockout of 12 genes significantly decreased HBV replication markers. Validation using siRNA knockdown in primary human hepatocytes confirmed several factors including the monoacylglycerol acyltransferase 2 (MOGAT2) gene as a bona fide HBV proviral factor. Further analysis with MGAT2 inhibitors demonstrated that inhibition of MOGAT2 activity impairs HBV transcription and replication. Our study demonstrates the value of the HBV reporter system in identifying previously unrecognized host metabolic factors important for HBV infection, offering a potential avenue for therapeutic development.