IL1R1 and obesity due to melanocortin 4 receptor deficiency: The authors used a series of dietary obesity and VAT transplantation experiments using Nlrp3−/− mutant mice and Tg mice with inducible deletion of IL1r1 (interleukin 1 receptor type 1) in CX3CR1(CX3C chemokine receptor 1)-expressing cells to verify their hypothesis.