Selective and differential roles of PVHCRH neurotransmitters in diet-induced obesity in mice

Stress and diet are known to synergistically promote risks of obesity but the underlying neural basis remains elusive. Corticotropin-releasing hormone neurons in the paraventricular hypothalamus (PVHCRH) are stress responsive and release both CRH and glutamate. Here we generated a mouse model with gain or loss of release in CRH or glutamate from PVHCRH neurons. While these models showed no changes in body weight when fed chow, they exhibited contrasting effects when fed high-fat high-caloric diets (HFD). Whereas disrupting glutamate release from PVHCRH neurons led to diet-induced obesity (DIO), that of CRH caused no impact. Conversely, augmented CRH release led to DIO while that of glutamate caused no impact. The observed DIO in both cases was associated with an increased drive for HFD, but without obvious changes in behavioral signs of anxiety. Our results suggest PVHCRH neurons as a key mediator for the exerbated DIO induced by maladaptive stress responses. The physiologic roles of the neurotransmission from PVHCRH neurons remain untested. Here, authors show differential roles of glutamate and CRH release from PVHCRH neurons in diet-induced obesity but a permissive role for their release in the HPA axis.