In obesity, the increased levels of circulating LPS from gut microbiota 11,12 and accumulated metabolic stress molecules (such as free fatty acids [FFAs] and cholesterol crystals) 2-4 act as the priming and activating signals, respectively, and lead to assembly and activation of the NLRP3 inflammasome. This evidence concerns the gene NLRP3 and obesity due to melanocortin 4 receptor deficiency.