Tight junction protein LSR is a host defense factor against SARS-CoV-2 infection in the small intestine

This is the authors' abstract. We don't add key points for this paper.

The identification of host factors with antiviral potential is important for developing effective prevention and therapeutic strategies against SARS-CoV-2 infection. Here, by using immortalized cell lines, intestinal organoids, ex vivo intestinal tissues and humanized ACE2 mouse model as proof-of-principle systems, we have identified lipolysis-stimulated lipoprotein receptor (LSR) as a crucial host defense factor against SARS-CoV-2 infection in the small intestine. Loss of endogenous LSR enhances ACE2-dependent infection by SARS-CoV-2 Spike (S) protein-pseudotyped virus and authentic SARS-CoV-2 virus, and exogenous administration of LSR protects against viral infection. Mechanistically, LSR interacts with ACE2 both in cis and in trans, preventing its binding to S protein, and thus inhibiting viral entry and S protein-mediated cell-cell fusion. Finally, a small LSR-derived peptide blocks S protein binding to the ACE2 receptor in vitro. These results identify both a previously unknown function for LSR in antiviral host defense against SARS-CoV-2, with potential implications for peptide-based pan-variant therapeutic interventions.