TGFB1 and diabetic kidney disease: In glomerular mesangial cells induced by high glucose for 6~24 hours, the expression of Smurf2 and Smad2/3 increased and on the contrary the expression of Smad7 decreased, so TGF-β signaling pathway was activated, which would induce the secretion of extracellular matrix protein FN and lead to fibrosis of diabetic nephropathy [48–50].