TLR4 and obesity due to melanocortin 4 receptor deficiency: Many studies indicate that TLR2 and TLR4 expression is increased in obesity and that global deficiency of TLR2 and TLR4 in DIO animal models ameliorates inflammation, insulin sensitivity, and weight gain, pointing to a pathogenic role of TLRs in obesity and insulin resistance via the induction of inflammation–although some discrepancies exist [47].