IRF3 and obesity due to melanocortin 4 receptor deficiency: In the previous section, we have described that STING-IRF3 can be activated in PA-induced endothelial cells, and this experiment also reported that in high-fat diet (HFD) mice, STING-IRF3 is also activated and that both HFD-induced inflammation and obesity are suppressed to some extent when STING is absent [88].