Preprint
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| PREPRINT-BIORXIV | ID: ppbiorxiv-466408
Mucinsplay an essential role in protecting the respiratory tract against microbial infections. The heavily O-glycosylated gel-forming mucins MUC5AC and MUC5B eliminate pathogens by mucociliary clearance while transmembrane mucins MUC1, MUC4, and MUC16 restrict microbial invasion at the apical surface of the epithelium. In this study, we determined the impact of host mucins and mucinglycans on SARS-CoV-2 spike-mediated epithelial entry. Humanlung epithelial Calu-3 cells have endogenous expression of the SARS-CoV-2 entry receptor ACE2 and express high levels of glycosylated MUC1 on the surface but not MUC4 and MUC16. Removal of the MUC1 extracellular domain (ED) using the O-glycan-specific mucinase StcE greatly enhanced spike binding and viral infection. By contrast, removal of mucinglycanssialic acid and fucose did not impact viral invasion. This study implicates the glycosylated ED of MUC1 as an important component of the host defense that restricts the severity of SARS-CoV-2 infection.