Increased expression of genes encoding, e.g., TNFα, IL-1β, IL-6, IL-18 and monocyte chemoattractant protein-1 (MCP-1) is consistently observed in adipose tissue of mice on HFD and mice genetically predisposed to obesity (e.g., in Lepob/ob a Leprdb/db mice with functional mutations of genes encoding leptin and leptin receptor, respectively) [39]. Here, CCL2 is linked to obesity due to melanocortin 4 receptor deficiency.