Abstract
Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a global pandemic. However, the mechanism of tissue tropism of SARS-CoV-2 remains unclear. Here, recombinant receptor-binding subdomain 1 of spike protein of SARS-CoV-2 (RBD-SD1) was used as a probe to investigate the potential tropism of SARS-CoV-2 in thirty-three types of normal human tissues. RBD-SD1 probe was observed to interact with cells in reported SARS-CoV-2 infected organs. Interestingly, the RBD-SD1 probe strongly interacted with bone marrow cells in an angiotensin-converting enzyme 2 (ACE2)-independent manner. In addition, SARS-CoV-2 induced the ACE2 mRNA expression in human primary bone marrow cells, suggesting human bone marrow cells may be sensitive to SARS-CoV-2 infection. Therefore, human bone marrow cells could be strongly infected by SARS-CoV-2, which may play an important role in the pathogenesis of COVID-19. These findings provide a deeper understanding of SARS-CoV-2 infection routes, thus contributing to the treatment of COVID-19.