TLR4 and obesity due to melanocortin 4 receptor deficiency: Ablation of various pattern recognition receptors (PRRs) such as TLR4, CD14, PKR, and NLRP3 protect mice from diet-/obesity-induced inflammation and insulin resistance (Shi et al, 2006; Cani et al, 2007; Nakamura et al, 2010; Vandanmagsar et al, 2011).