Genome-wide CRISPR/Cas9 screen identifies SLC39A9 and PIK3C3 as crucial entry factors for Ebola virus infection

The Ebola virus (EBOV) has emerged as a significant global health concern, notably during the 2013-2016 outbreak in West Africa. Despite the clinical approval of two EBOV antibody drugs, there is an urgent need for more diverse and effective antiviral drugs, along with comprehensive understanding of viral-host interactions. In this study, we harnessed a biologically contained EBOVΔVP30-EGFP cell culture model which could recapitulate the entire viral life cycle, to conduct a genome-wide CRISPR/Cas9 screen. Through this, we identified PIK3C3 (phosphatidylinositide 3-kinase) and SLC39A9 (zinc transporter) as crucial host factors for EBOV infection. Genetic depletion of SLC39A9 and PIK3C3 lead to reduction of EBOV entry, but not impact viral genome replication, suggesting that SLC39A9 and PIK3C3 act as entry factors, facilitating viral entry into host cells. Moreover, PIK3C3 kinase activity is indispensable for the internalization of EBOV virions, presumably through the regulation of endocytic and autophagic membrane traffic, which has been previously recognized as essential for EBOV internalization. Notably, our study demonstrated that PIK3C3 kinase inhibitor could effectively block EBOV infection, underscoring PIK3C3 as a promising drug target. Furthermore, biochemical analysis showed that recombinant SLC39A9 protein could directly bind viral GP protein, which further promotes the interaction of viral GP protein with cellular receptor NPC1. These findings suggests that SLC39A9 plays dual roles in EBOV entry. Initially, it serves as an attachment factor during the early entry phase by engaging with the viral GP protein. Subsequently, SLC39A9 functions an adaptor protein, facilitating the interaction between virions and the NPC1 receptor during the late entry phase, prior to cathepsin cleavage on the viral GP. In summary, this study offers novel insights into virus-host interactions, contributing valuable information for the development of new therapies against EBOV infection.