We have recently highlighted the significant role of FXR in T2DM, where the reduced expression of FXR results in impaired insulin secretion, while the activation of FXR leads to the enhancement of insulin secretion and incretin effect after Roux-en-Y gastric bypass (RYGB) surgery by regulating the expression of TRPA1 or GLP-1R [13, 14]. This evidence concerns the gene NR1H4 and type 2 diabetes mellitus.