ARG1 and obesity due to melanocortin 4 receptor deficiency: Zhao et al. (2018) found that ASC-exos could transfer into macrophages to induce anti-inflammatory M2 phenotypes through the transactivation of arginase 1 (Arg-1) and IL-10 by exosome-carried active STAT3, and increase the expression of uncoupling protein 1 (UCP-1) to promote white adipose tissue (WAT) beiging, thereby improving obesity-related inflammation and metabolism (Figure 3).