MAPK8 and obesity due to melanocortin 4 receptor deficiency: Nevertheless, studies have shown that the deletion of JNK1 and IKKβ in neurons can rescue leptin and insulin signaling in the hypothalamus, as well as reduce weight gain and restore the metabolic alterations linked to obesity (Belgardt et al., 2010; Sabio et al., 2010; Zhang et al., 2008).