FFAR2 and obesity due to melanocortin 4 receptor deficiency: FFAR2 has also been implicated in regulatory macrophage activation, as M2- but not M1-type macrophages from adipose tissue were activated by FFAR2, presumably accounting for the tissue remodeling and anti-adipogenic effect of M2 macrophages in chronic inflammatory and insulin desensitization diseases such as obesity [138].