CERS6 and obesity due to melanocortin 4 receptor deficiency: Together, these observations suggest that the increase in C16:0 ceramide levels and that of CerS6 expression in the hypothalamus of HFD-fed mice is mainly due to regulation in neurons compared to other cell types, indicative of a critical role of CerS6-derived C16:0 ceramides in hypothalamic neurons in obesity.