2.4. High-density lipoprotein (HDL) scavenger receptor B type 1 (SR-B1)
SR-B1 is a cell-surface HDL receptor that mediates the selective uptake of cholesteryl esters and other lipid components of receptor-bound HDL particles (Shen, Asthana, Kraemer & Azhar, 2018). Co-expression of SR-B1and ACE2 has been found in human pulmonary and extrapulmonary tissues (Wei et al., 2020).
SR-B1 may be associated with the facilitating the attachment of SARS-CoV-2 on ACE2-expressing cells. HDL can interact with the S1 domain of S-protein. Blockade of the cholesterol-binding site on the S1 domain with either a monoclonal antibody or SR-B1 inhibitors prevents HDL-enhanced SARS-CoV-2 infection (Wei et al., 2020). Although the interaction between HDL and S-protein may not the be the major mechanism of viral entry, blockade of this interaction should be beneficial to reduce the viral load.