STAT3 and obesity due to melanocortin 4 receptor deficiency: Instead, as suggested by our findings for both the genetic ablation of macrophage Stat3 and silencing Stat3 through CpG-Stat3siRNA in the myeloid compartment, the signaling pathway within macrophage/myeloid cells rather than M1/M2 is more critical for obesity/inflammation-mediated insulin resistance.