The binding of LPS to TLR4 can activate a wide array of cellular signaling pathways, inducing inflammation responses and the expression and secretion of cytokines within adipocytes and macrophages, leading to insulin resistance development and increased obesity (Medzhitov and Horng, 2009; Abdallah Ismail et al., 2011). Here, TLR4 is linked to obesity due to melanocortin 4 receptor deficiency.