NR1H4 and obesity due to melanocortin 4 receptor deficiency: BAs regulates metabolism mainly by activating two primary receptors, namely the nuclear farnesoid X receptor (FXR) and the membrane-bound Takeda G protein-coupled receptor 5 (TGR5) (Chiang and Ferrell 2019), which have been demonstrated to exert renoprotective effects in diabetes and obesity (Wang et al. 2018).