IL6 and obesity due to melanocortin 4 receptor deficiency: In an in vitro model of obesity-associated cellular stress, exposure of preadipocytes and adipocytes to palmitate and TNF-α significantly increased markers of hypoxia (HIF-α, GLUT1, VEGF), ER stress (sXBP1, CHOP, BiP/GRP78), and inflammation (IL-6, MCP-1, and TNF-α) [85,88].