In mice, HFD-induced obesity increased macrophage infiltration and expression of pro-inflammatory cytokines such as tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6) in mesenteric WAT, and increased TNF-α expression in the gut (Lam et al., 2012, 2015). Here, IL6 is linked to obesity due to melanocortin 4 receptor deficiency.