HMGB1 and obesity due to melanocortin 4 receptor deficiency: Immune cell activation in obesity is primarily triggered by DAMPs, such as free fatty acids, low-density lipoprotein cholesterol (LDL-c), uric acid, high-mobility group box 1 (HMGB1) protein, mitochondrial deoxyribonucleic acid (DNA), and extracellular adenosine triphosphate (ATP).