CCL2 and obesity due to melanocortin 4 receptor deficiency: In obesity, hypertrophic adipose tissue secretes proinflammatory cytokines, including interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and monocyte chemoattractant protein-1 (MCP-1), which perpetuate systemic insulin resistance and endothelial dysfunction via NF-κB and JNK signaling pathways (14–16).