Non-neural expression of SARS-CoV-2 entry genes in the olfactory epithelium suggests mechanisms underlying anosmia in COVID-19 patients

David Brann; Tatsuya Tsukahara; Caleb Weinreb; Darren W. Logan; Sandeep Robert Datta

Here we demonstrate that subsets of OE sustentacular cells, HBCs, microvillar cells and Bowman's gland cells express the CoV-2 receptor ACE2 and the spike protein protease TMPRSS2. Human OE sustentacular cells express these genes at levels comparable to that observed in lung cells. However, we failed to detect ACE2 expression in mature OSNs at either the transcript or protein levels. These observations suggest that CoV-2 does not directly enter OSNs, but instead may target OE support and stem cells. Similarly, neurons in the olfactory bulb fail to express ACE2, whereas vascular pericytes do. Thus primary infection of non-neuronal cell typesrather than sensory or bulb neuronsmay be responsible for anosmia and related disturbances in odor perception in COVID-19 patients.