NLRP1 and obesity due to melanocortin 4 receptor deficiency: In summary, it is likely that the two inflammasome sensors, NLRP1 and NLRP3, exert opposite effects in obesity; NLRP1 cleavage of IL-18 acts to limit metabolic dysfunction, while NLRP3 activation of IL-1β is detrimental and promotes glucose intolerance.