CCL2 and obesity due to melanocortin 4 receptor deficiency: During the development of diet-induced obesity, transcription of several pro-inflammatory cytokines and chemokines such as disintegrin and metallopeptidase domain 8 (Adam8), Emr1, interleukin 1 receptor antagonist (Il1rn), tumor necrosis factor (Tnf), serum amyloid A 3 (Saa3), integrin alpha-M (Itgam), chemokine (C-C motif) ligand 2 (Ccl2), ligand 3 (Ccl3), ligand 4 (Ccl4), ligand 6 (Ccl6), ligand 7 (Ccl7) and ligand 9 (Ccl9), were significantly elevated in epididymal WAT between week 20 and 24 (Fig. 6A).