CCL2 and obesity due to melanocortin 4 receptor deficiency: Excess WAT causes obesity and is associated with adipose tissue inflammation and increased secretion of leptin, fatty acid-binding protein (FABP4), and proinflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1)3,4.