RETN and obesity due to melanocortin 4 receptor deficiency: Loss of TG2 did not affect the obesity-related alterations in the expression levels of the adiponectin and resistin (Fig. 1c), but obesity-induced expressions of TNF-α, MCP-1, and leptin were significantly enhanced in the gWAT adipocytes of TG2 null animals as compared to wild type mice (Fig. 1c).