We found that CRTC2 expression is elevated in DKD, and CRTC2 may promote the transdifferentiation of diabetic renal tubular epithelial cells through the CREB-Smad2/3 signaling pathway, leading to renal interstitial fibrosis (the related mechanism is shown in Fig. 6). This evidence concerns the gene CRTC2 and diabetic kidney disease.