FPR2 and obesity due to melanocortin 4 receptor deficiency: Sun et al. (2021) found that FPR2 not only directly chemotacticizes neutrophils, but also regulates chemokine production to control chemotactic neutrophil infection. FPR2-induced monocyte and neutrophil chemotaxis and recruitment mediates the effects of neutrophils by regulating macrophage M1 polarization-mediated inflammation and plays a key role in high-fat diet (HFD)-induced obesity and its associated complications (Chen et al., 2019).