Determinants of SARS-CoV-2 entry and replication in airway mucosal tissue and susceptibility in smokers.
Nakayama T*, Lee IT*,#, Jiang S*, Matter MS*, Yan CH*, Overdevest JB*, Wu CT*, Goltsev Y*, Shih LC, Liao KC, Zhu B, Bai Y, Lidsky P, Xiao Y, Zarabanda D, Yang A, Easwaran M, Schürch CM, Chu P, Chen H, Stalder AK, McIlwain DR, Borchard NA, Gall PA, Dholakia SS, Xu L, Tai CJ, Yeh TH, Duran JM, Mertz KD, Patel ZM, Haslbauer JD, Jackson PK, Menter T, Andino R, Canoll PD, DeConde AS, Hwang PH, Tzankov A#, Nolan GP#, Nayak JV#.
Understanding viral tropism is an essential step toward reducing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission, decreasing mortality from coronavirus disease 2019 (COVID-19) and limiting opportunities for mutant strains to arise. Currently, little is known about the extent to which distinct tissue sites in the human head and neck region and proximal respiratory tract selectively permit SARS-CoV-2 infection and replication. In this translational study, we discover key variabilities in expression of angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2), essential SARS-CoV-2 entry factors, among the mucosal tissues of the human proximal airways. We show that SARS-CoV-2 infection is present in all examined head and neck tissues, with a notable tropism for the nasal cavity and tracheal mucosa. Finally, we uncover an association between smoking and higher SARS-CoV-2 viral infection in the human proximal airway, which may explain the increased susceptibility of smokers to developing severe COVID-19. This is at least partially explained by differences in interferon (IFN)-β1 levels between smokers and non-smokers.