CGAS and obesity due to melanocortin 4 receptor deficiency: Obesity leads to an increase in the level of free fatty acids in the peripheral circulation, which promotes the leakage of mitochondrial DNA from vascular endothelial cells into the cytoplasm, which activates the cGAS-STING-IRF3 pathway and up-regulates the expression of ICAM-1, eventually contributing to vascular endothelial inflammation (35).