Fig. 4

TMPRSS2-mediated upregulation of ACE2 expression. A: ACE2 serves as a receptor for the entry of SARS-CoV-2, while TMPRSS2 is involved in the activation of the spike (S) protein. These are crucial elements for comprehending the pathophysiology of COVID-19. B: ACE2 expression of TMPRSS2^high and mock-transfected EA.Hy926 cells was determined by Western blot using an anti-ACE2 as well as anti-TMPRSS2 mAb. C: A correlation plot illustrates the association of ACE2 and TMPRSS2 expression in PBMNCs of COVID-19 patients (COVID-19db)