In the context of obesity, the activation of M1 macrophages is stimulated by the JAK-STAT (Janus kinase-signal transducer and activator of transcription) pathway in conjunction with NF-κB and MAPK (mitogen-activated protein kinase), and miR-155 promotes this process by inhibiting the production of essential anti-inflammatory mediators [51]. This evidence concerns the gene NFKB1 and obesity due to melanocortin 4 receptor deficiency.