SUCNR1 and obesity due to melanocortin 4 receptor deficiency: In SUCNR1-deficient mouse models, succinate-SUCNR1 signaling initiates type 2 immune responses in the intestine, facilitates the development of barrier-promoting goblet cells, mitigates high-fat diet (HFD)-induced mucosal barrier impairments and intestinal dysbiosis, and ultimately exhibits anti-obesity effects.