MAPK8 and obesity due to melanocortin 4 receptor deficiency: The role of hepatic JNK signaling is even less clear in this regard, but some evidence demonstrates that it contributes to diet-induced obesity and hepatic steatosis as well as to cholesterol and BA metabolism (Manieri et al., 2020; Manieri and Sabio, 2015; Vernia et al., 2014).