CCL2 and obesity due to melanocortin 4 receptor deficiency: Activated stress pathways found in obesity drive the expression of chemokines like C-C motif chemokine ligand 2 (CCL2), CCL8, and CCL5, and chemokine receptors (e.g. CCR2 and CCR5), which help recruit macrophages to the dysfunctional tissue [108, 113].