CCL2 and obesity due to melanocortin 4 receptor deficiency: Histone acetylation of the pro-inflammatory genes, tumor necrosis factor alpha (TNFA) and monocyte chemotactic protein 1 (MCP1; also called CD2) have been up-regulated in a murine model of obesity (225), and the histone acetylation of the gene stimulating transcription of fatty acid synthase (FASN) has been associated with de novo lipogenesis in human hepatocytes (226) (Table 4).