Upregulation of osteopontin gene expression in diabetic rat proximal tubular cells revealed by microarray profiling

Kidney Int. 2006 Mar;69(6):1005-15. doi: 10.1038/sj.ki.5000206.


Progression of diabetic nephropathy appears directly related to renal tubulointerstitial injury, but the involved genes are incompletely delineated. To identify such genes, DNA microarray analysis was performed with RNA from renal proximal tubules (RPTs) of streptozotocin-induced diabetic Wistar rats, spontaneously diabetic BioBreeding rats, and rat immortalized renal proximal tubular cells (IRPTCs) exposed to high glucose (25 mM) medium for 2 weeks. Osteopontin (OPN) mRNA expression was quantified by real time-quantitative polymerase chain reaction (RT-qPCR) or conventional reverse transcriptase-polymerase chain reaction (RT-PCR). OPN mRNA expression was upregulated (5-70-fold increase) in diabetic rat RPTs and in IRPTCs chronically exposed to high glucose compared to control RPTs and IRPTCs. High glucose, angiotensin II, phorbol 12-myristate 13-acetate and transforming growth factor-beta 1 (TGF-beta1) stimulated OPN mRNA expression in IRPTCs in a dose- and time-dependent manner. This effect was inhibited by tiron, taurine, diphenylene iodinium, losartan, perindopril, calphostin C, or LY 379196 but not PD123319. IRPTCs overexpressing dominant-negative protein kinase C-beta 1 (PKC-beta1) cDNA or antisense TGF-beta1 cDNA prevented the high glucose effect on OPN mRNA expression. We concluded that high glucose-mediated increases in OPN gene expression in diabetic rat RPTs and IRPTCs are mediated, at least in part, via reactive oxygen species generation, intrarenal rennin-angiotensin system activation, TGF-beta1 expression, and PKC-beta1 signaling.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Angiotensin II / pharmacology
  • Animals
  • Diabetes Mellitus, Experimental / genetics*
  • Diabetic Nephropathies / genetics
  • Diabetic Nephropathies / physiopathology
  • Gene Expression / drug effects
  • Gene Expression Profiling*
  • Glucose / pharmacology
  • Glycoproteins / analysis*
  • Glycoproteins / genetics*
  • Kidney Tubules, Proximal / chemistry*
  • Kidney Tubules, Proximal / metabolism
  • Kidney Tubules, Proximal / pathology
  • Male
  • Oligonucleotide Array Sequence Analysis*
  • Protein Kinase C / physiology
  • Protein Kinase C beta
  • RNA, Messenger / analysis
  • Rats
  • Rats, Inbred BB
  • Rats, Wistar
  • Reactive Oxygen Species / metabolism
  • Renin-Angiotensin System / physiology
  • Reverse Transcriptase Polymerase Chain Reaction
  • Signal Transduction / physiology
  • Tetradecanoylphorbol Acetate / pharmacology
  • Transforming Growth Factor beta / genetics
  • Transforming Growth Factor beta / pharmacology
  • Transforming Growth Factor beta1
  • Up-Regulation / genetics*


  • Glycoproteins
  • RNA, Messenger
  • Reactive Oxygen Species
  • Tgfb1 protein, rat
  • Transforming Growth Factor beta
  • Transforming Growth Factor beta1
  • osteopoietin
  • Angiotensin II
  • Protein Kinase C
  • Protein Kinase C beta
  • Glucose
  • Tetradecanoylphorbol Acetate