TLR2 and obesity due to melanocortin 4 receptor deficiency: As shown in previous studies, TLR2-deficiency in adult mice improves insulin sensitivity, attenuates adipocyte hypertrophy, and reduces inflammatory cytokine expression in mice that were fed HFD (Himes and Smith, 2010; Kellermayer et al., 2011); as such, we hypothesize that postnatal HFD-induced obesity and insulin resistance is reduced in TLR2-deficient offspring-pLPS.