RT Journal Article SR Electronic T1 Gene expression and in situ protein profiling of candidate SARS-CoV-2 receptors in human airway epithelial cells and lung tissue JF bioRxiv FD Cold Spring Harbor Laboratory SP 2020.04.07.030742 DO 10.1101/2020.04.07.030742 A1 Aguiar, Jennifer A. A1 Tremblay, Benjamin J-M. A1 Mansfield, Michael J. A1 Woody, Owen A1 Lobb, Briallen A1 Banerjee, Arinjay A1 Chandiramohan, Abiram A1 Tiessen, Nicholas A1 Dvorkin-Gheva, Anna A1 Revill, Spencer A1 Miller, Matthew S. A1 Carlsten, Christopher A1 Organ, Louise A1 Joseph, Chitra A1 John, Alison A1 Hanson, Paul A1 McManus, Bruce M. A1 Jenkins, Gisli A1 Mossman, Karen A1 Ask, Kjetil A1 Doxey, Andrew C. A1 Hirota, Jeremy A. YR 2020 UL http://biorxiv.org/content/early/2020/04/12/2020.04.07.030742.abstract AB In December 2019, SARS-CoV-2 emerged causing the COVID-19 pandemic. SARS-CoV, the agent responsible for the 2003 SARS outbreak, utilizes ACE2 and TMPRSS2 host molecules for viral entry. ACE2 and TMPRSS2 have recently been implicated in SARS-CoV-2 viral infection. Additional host molecules including ADAM17, cathepsin L, CD147, and GRP78 may also function as receptors for SARS-CoV-2.To determine the expression and in situ localization of candidate SARS-CoV-2 receptors in the respiratory mucosa, we analyzed gene expression datasets from airway epithelial cells of 515 healthy subjects, gene promoter activity analysis using the FANTOM5 dataset containing 120 distinct sample types, single cell RNA sequencing (scRNAseq) of 10 healthy subjects, immunoblots on multiple airway epithelial cell types, and immunohistochemistry on 98 human lung samples.We demonstrate absent to low ACE2 promoter activity in a variety of lung epithelial cell samples and low ACE2 gene expression in both microarray and scRNAseq datasets of epithelial cell populations. Consistent with gene expression, rare ACE2 protein expression was observed in the airway epithelium and alveoli of human lung. We present confirmatory evidence for the presence of TMPRSS2, CD147, and GRP78 protein in vitro in airway epithelial cells and confirm broad in situ protein expression of CD147 in the respiratory mucosa.Collectively, our data suggest the presence of a mechanism dynamically regulating ACE2 expression in human lung, perhaps in periods of SARS-CoV-2 infection, and also suggest that alternate receptors for SARS-CoV-2 exist to facilitate initial host cell infection.Competing Interest StatementThe authors have declared no competing interest.