title: Endothelial-myofibroblast transition contributes to the early development of diabetic renal interstitial fibrosis in streptozotocin-induced diabetic mice.
abstract: 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.
authors.affiliation: Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria 3800, Australia. jinhua.li@med.monash.edu.au
authors.forename: Jinhua
authors.initials: J
authors.lastname: Li
authors.forename: Xinli
authors.initials: X
authors.lastname: Qu
authors.forename: John F
authors.initials: JF
authors.lastname: Bertram
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D019070:Cell Lineage / Q000187:drug effects; D003921:Diabetes Mellitus, Experimental / Q000150:complications* / Q000473:pathology*; D003928:Diabetic Nephropathies / Q000150:complications* / Q000473:pathology*; D004727:Endothelium / Q000187:drug effects / Q000473:pathology*; D005347:Fibroblasts / Q000187:drug effects / Q000473:pathology*; D005355:Fibrosis; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D019426:Integrases / Q000378:metabolism; D007678:Kidney Glomerulus / Q000187:drug effects / Q000473:pathology; D051379:Mice; D018613:Microscopy, Confocal; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism; D042787:Receptor, TIE-2; D013311:Streptozocin; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology
chemical_list: D000199:Actins; D053773:Transforming Growth Factor beta1; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D013311:Streptozocin; D020794:Receptor Protein-Tyrosine Kinases; D042787:Receptor, TIE-2; C079086:Tek protein, mouse; C045073:Cre recombinase; D019426:Integrases