Figure Legend

Figure 1: The metabolic pathway of vitamin D synthesis and the tissue specific cellular response it mediates that may reduce COVID-19 severity. CYP2R1, CYP27A1, and CYP27B1 are the cytochrome enzymes involve in the hydroxylation processes of cholecalciferol to the active form of vitamin D, 1,25(OH)2D. 1,25(OH)2D then binds to VDR which forms a heterodimer with retinoid X receptor (RXR). Interaction of the heterodimer with the vitamin D response element (VDRE) leads to downstream target gene regulation.