IL1B and obesity due to melanocortin 4 receptor deficiency: Notwithstanding, the main source of mature IL-1β is produced and secreted by the canonical inflammasome activation following a priming signal, such as activation of Toll-like receptor (TLR4) by lipopolysaccharides (LPS) derived from bacteria leaking from gut or by free fatty acids (FFA) in the context of obesity.