Antioxidant treatment induces transcription and expression of transforming growth factor beta in cultured renal proximal tubular cells

FEBS Lett. 2001 Jan 19;488(3):154-9. doi: 10.1016/s0014-5793(00)02403-0.


Transforming growth factor beta (TGF-beta) plays an important role in the development of tubulointerstitial fibrosis in chronic renal disease. We were interested whether interference with oxygen radicals may modulate TGF-beta expression. Unexpectedly, we discovered that diphenylene iodine (DIP), an inhibitor of NADP(H) oxidase, induces a robust increase in TGF-beta transcript expression in cultured mouse proximal tubular cells (MCT cells). A similar increase was seen with EUK-8, a synthetic salen-manganese complex with high oxyradical scavenger activities. This induction of TGF-beta1 mRNA was paralleled by increasing protein expression. Transient transfection of MCT cells with a reporter construct in which murine TGF-beta1 enhancer/promoter elements were cloned in front of the luciferase gene, revealed that DIP, EUK-8, and Tiron all stimulated transcription of the TGF-beta1 gene whereas exogenous H2O2 suppressed transcription. Antisense oligonucleotides against p22phox, but not sense oligonucleotides, also increased transcriptional activity of TGF-beta1. Mutagenesis of Sp1 binding sites in the mouse TGF-beta1 enhancer/promoter abolished the stimulatory effect of the antioxidants. Gel shift experiments revealed that DIP as well as EUK-8 activated binding of nuclear proteins to Sp1 consensus sequence. Our data provide evidence that TGF-beta1 transcription is negatively regulated in MCT cells under basal conditions by NADP(H) oxidase-mediated oxygen radicals. Thus, antioxidant therapy may increase local synthesis of TGF-beta1 in the tubulointerstitium.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt / pharmacology
  • Animals
  • Antioxidants / pharmacology*
  • Blotting, Western
  • Cell Line
  • Consensus Sequence / genetics
  • DNA / genetics
  • DNA / metabolism
  • Ethylenediamines / pharmacology
  • Genes, Reporter / genetics
  • Hydrogen Peroxide / pharmacology
  • Iodine / chemistry
  • Kidney Tubules, Proximal / cytology
  • Kidney Tubules, Proximal / drug effects*
  • Kidney Tubules, Proximal / metabolism
  • Membrane Transport Proteins*
  • Mice
  • Mutation / genetics
  • NADPH Dehydrogenase / genetics
  • NADPH Oxidases / antagonists & inhibitors
  • NADPH Oxidases / metabolism
  • Oligonucleotides, Antisense / genetics
  • Organometallic Compounds / pharmacology
  • Phosphoproteins / genetics
  • Protein Binding
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Response Elements / genetics
  • Sp1 Transcription Factor / metabolism
  • Transcriptional Activation / drug effects*
  • Transfection
  • Transforming Growth Factor beta / genetics*
  • Transforming Growth Factor beta / metabolism
  • Transforming Growth Factor beta1


  • Antioxidants
  • Ethylenediamines
  • Membrane Transport Proteins
  • Oligonucleotides, Antisense
  • Organometallic Compounds
  • Phosphoproteins
  • RNA, Messenger
  • Sp1 Transcription Factor
  • TGFB1 protein, human
  • Tgfb1 protein, mouse
  • Transforming Growth Factor beta
  • Transforming Growth Factor beta1
  • 1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt
  • N,N'-bis(salicylideneamino)ethane-manganese(II)
  • DNA
  • Iodine
  • Hydrogen Peroxide
  • NADPH Oxidases
  • CYBA protein, human
  • NADPH Dehydrogenase