Endothelial-myofibroblast transition contributes to the early development of diabetic renal interstitial fibrosis in streptozotocin-induced diabetic mice

Am J Pathol. 2009 Oct;175(4):1380-8. doi: 10.2353/ajpath.2009.090096. Epub 2009 Sep 3.


Diabetic nephropathy is the leading cause of chronic renal failure. Myofibroblasts play a major role in the synthesis and secretion of extracellular matrix in diabetic renal fibrosis. Increasing evidence suggests that endothelial cells may undergo endothelial-myofibroblast transition under physiological and pathophysiological circumstances. Therefore, this study investigates whether endothelial-myofibroblast transition occurs and contributes to the development of diabetic renal interstitial fibrosis. Diabetes was induced by administration of streptozotocin to Tie2-Cre;LoxP-EGFP mice, an endothelial lineage-traceable mouse line generated by crossbreeding B6.Cg-Tg(Tek-cre)12F1v/J mice with B6.Cg-Tg(ACTB-Bgeo/GFP)21Lbe/J mice. The endothelial-myofibroblast transition was also studied in MMECs (a mouse pancreatic microvascular endothelial cell line) and primary cultures of CD31+/EYFP- (enhanced yellow fluorescent protein) endothelial cells isolated from adult normal alpha-smooth muscle actin promoter-driven-EYFP (alpha-SMA/EYFP) mouse kidneys. Confocal microscopy demonstrated that 10.4 +/- 4.2 and 23.5 +/- 7.4% of renal interstitial myofibroblasts (alpha-SMA+) in 1- and 6-month streptozotocin-induced diabetic kidneys were of endothelial origin (EGFP+/alpha-SMA+ cells), compared with just 0.2 +/- 0.1% of myofibroblasts in vehicle-treated Tie2-Cre;LoxP-EGFP mice (P < 0.01). Confocal microscopy and real-time PCR showed that transforming growth factor (TGF)-beta1 induced de novo expression of alpha-SMA and loss of expression of VE-cadherin and CD31 in MMECs and primary cultures of renal endothelial cells in a time- and dose-dependent fashion. These findings demonstrate that the endothelial-myofibroblast transition occurs and contributes to the early development and progression of diabetic renal interstitial fibrosis and suggest that the endothelial-myofibroblast transition may be a therapeutic target.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / metabolism
  • Animals
  • Cell Lineage / drug effects
  • Diabetes Mellitus, Experimental / complications*
  • Diabetes Mellitus, Experimental / pathology*
  • Diabetic Nephropathies / complications*
  • Diabetic Nephropathies / pathology*
  • Endothelium / drug effects
  • Endothelium / pathology*
  • Fibroblasts / drug effects
  • Fibroblasts / pathology*
  • Fibrosis
  • Green Fluorescent Proteins / metabolism
  • Humans
  • Integrases / metabolism
  • Kidney Glomerulus / drug effects
  • Kidney Glomerulus / pathology
  • Mice
  • Microscopy, Confocal
  • Receptor Protein-Tyrosine Kinases / metabolism
  • Receptor, TIE-2
  • Streptozocin
  • Transforming Growth Factor beta1 / pharmacology


  • Actins
  • Transforming Growth Factor beta1
  • enhanced green fluorescent protein
  • Green Fluorescent Proteins
  • Streptozocin
  • Receptor Protein-Tyrosine Kinases
  • Receptor, TIE-2
  • Tek protein, mouse
  • Cre recombinase
  • Integrases