ERN1 and obesity due to melanocortin 4 receptor deficiency: In the adipose tissue macrophage, IRE1α deletion in myeloid lineage using Ern1fl/fl;Lyz2-cre was reported to induce the beiging of WAT and protect against diet-induced obesity by augmenting M2 macrophage population through its synthesis and secretion of catecholamine (Shan et al., 2017).