Genome-wide bidirectional CRISPR screens identify mucins as host factors modulating SARS-CoV-2 infection

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes a range of symptoms in infected individuals, from mild respiratory illness to acute respiratory distress syndrome. A systematic understanding of host factors influencing viral infection is critical to elucidate SARS-CoV-2-host interactions and the progression of Coronavirus disease 2019 (COVID-19). Here, we conducted genome-wide CRISPR knockout and activation screens in human lung epithelial cells with endogenous expression of the SARS-CoV-2 entry factors ACE2 and TMPRSS2. We uncovered proviral and antiviral factors across highly interconnected host pathways, including clathrin transport, inflammatory signaling, cell-cycle regulation, and transcriptional and epigenetic regulation. We further identified mucins, a family of high molecular weight glycoproteins, as a prominent viral restriction network that inhibits SARS-CoV-2 infection in vitro and in murine models. These mucins also inhibit infection of diverse respiratory viruses. This functional landscape of SARS-CoV-2 host factors provides a physiologically relevant starting point for new host-directed therapeutics and highlights airway mucins as a host defense mechanism. Genome-wide CRISPR knockout and activation screens in human lung epithelial cells with endogenous expression of the SARS-CoV-2 entry factors ACE2 and TMPRSS2 identify mucins as key host factors restricting viral infection.

Automated summary

This study identified mucins as key host factors restricting viral infection, through genome-wide CRISPR knockout and activation screens in human lung epithelial cells expressing the SARS-CoV-2 entry factors ACE2 and TMPRSS2. These mucins serve as a significant viral restriction network inhibiting SARS-CoV-2 infection and other respiratory viruses. The findings provide a starting point for new host-directed therapeutics and highlight airway mucins as an important host defense mechanism.