SARS-CoV-2 Entry Receptor ACE2 Is Expressed on Very Small CD45- Precursors of Hematopoietic and Endothelial Cells and in Response to Virus Spike Protein Activates the Nlrp3 Inflammasome. Angiotensin-converting enzyme 2 (ACE2) plays an important role as a member of the renin-angiotensin-aldosterone system (RAAS) in regulating the conversion of angiotensin II (Ang II) into angiotensin (1-7) (Ang [1-7]). But at the same time, while express