DNMT1 and obesity due to melanocortin 4 receptor deficiency: In macrophages isolated from hyperlipidemia and a T2D mouse model of hindlimb ischemia, inflammatory genes are hypomethylated, and M2 genes are hypermethylated.128 In obesity patients, DNMT3B and DNMT1 expression are enhanced, leading to DNA methylation of the promoter of PPAR1, which may induce M2-associated gene suppression and contribute to an inflammatory macrophage phenotype.129 Therefore, the deletion of DNMT1 by using 5-aza-2′-deoxycytidine in pharmacology could promote alternative activation and inhibit macrophage inflammation.