IL-13 protects epithelial cells from SARS-CoV-2 infection by inhibiting early ACE2-mediated events

Abstract Severe Acute Respiratory Syndrome coronavirus-2 (SARS-CoV-2) infection is mediated by binding of viral spike (S) protein to membrane ACE2 on host epithelial cells, preferentially in the airway. Asthmatics with type 2 (T2) inflammation are reportedly less susceptible to disease, but the underlying mechanisms are unclear. We recently showed that ACE2expression is decreased in airway epithelial cells from T2 asthmatics and is consistently suppressed in human primary epithelial cells cultured with IL-13 (PMID: 32422146). To dissect IL-13/SARS-CoV-2 interactions, we assessed the effects of IL-13 on discrete events in SARS-CoV-2 infection. S1 protein binding to green monkey kidney Vero E6, human lung Calu-3 epithelial cells and HEK293T cells stably transfected with human ACE2(hACE2-HEK293T) was measured by flow cytometry with His-tagged S1 protein. S protein-mediated viral entry into Vero E6 and hACE2-HEK293T cells was assessed using S protein-pseudotyped lentiviral particles carrying a GFP reporter. ACE2transcription in Vero E6, Calu-3 and primary human airway epithelial cells was measured by RT-qPCR. ACE2 expression on Vero E6, Calu-3 and hACE2-HTK293T cells was evaluated by flow cytometry. USA-WA1/2020 SARS-CoV-2 was used to infect Calu-3 cells. IL-13 strongly inhibited S protein binding, cell entry, and infection of epithelial cells by SARS-CoV-2. These effects resulted at least in part from IL-13-dependent inhibition of ACE2expression because IL-13 did not affect S protein binding to, and S protein-pseudotyped lentivirus entry into, hACE2-HEK293T cells that do not downregulate ACE2 in response to IL-13. We suggest that IL-13 protects epithelial cells from SARS-CoV-2 infection by inhibiting early ACE2-mediated events. Supported by grant from NIAID: U19 AI125357