In Figure 2, we can further speculate that melanocortin receptors (MC2R) can be selectively activated by the adrenocorticotropic hormone ACTH in COVID-19, and TREK1 could activate phospholipase C (PLC beta), which catalyzes the formation of inositol 1,4,5-trisphosphate and diacylglycerol from phosphatidylinositol 4,5-bisphosphate. Here, POMC is linked to COVID-19.