INS and obesity due to melanocortin 4 receptor deficiency: MiR-30b and miR-30c have been proven to promote beige fat development and regulate receptor-interacting protein 140 (RIP140) [44], of which deficiency determines a lean phenotype and resistance to obesity in mice [45]; furthermore, miR-30b was up-regulated in the liver of high-fat diet-induced obese rats and was positively correlated with hepatic steatosis while its inhibition improved insulin sensitivity [46].