Role of connective tissue growth factor in fibronectin expression and tubulointerstitial fibrosis.
Connective tissue growth factor (CTGF) is one of the candidate factors mediating downstream events of transforming growth factor-beta (TGF-beta), but its role in fibrogenic properties of TGF-beta and in tubulointerstitial fibrosis has not yet been clarified. Using unilateral ureteral obstruction (UUO) in rats, we analyzed gene expression of TGF-beta1, CTGF, and fibronectin. We further investigated the effect of blockade of endogenous CTGF on TGF-beta-induced fibronectin expression in cultured rat renal fibroblasts by antisense oligodeoxynucleotide (ODN) treatment. After UUO, CTGF mRNA expression in the obstructed kidney was significantly upregulated subsequent to TGF-beta1, followed by marked induction of fibronectin mRNA. By in situ hybridization, CTGF mRNA was detected mainly in the interstitial fibrotic areas and tubular epithelial cells as well as in parietal glomerular epithelial cells in the obstructed kidney. The interstitial cells expressing CTGF mRNA were also positive for alpha-smooth muscle actin. CTGF antisense ODN transfected into cultured renal fibroblasts significantly attenuated TGF-beta-stimulated upregulation of fibronectin mRNA and protein compared with control ODN transfection, together with inhibited synthesis of type I collagen. With the use of a reporter assay, rat fibronectin promoter activity was increased by 2.5-fold with stimulation by TGF-beta1, and this increase was abolished with antisense CTGF treatment. Thus CTGF plays a crucial role in fibronectin synthesis induced by TGF-beta, suggesting that CTGF blockade could be a possible therapeutic target against tubulointerstitial fibrosis.
Yokoi
Hideki
H
Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan.
Mukoyama
Masashi
M
Sugawara
Akira
A
Mori
Kiyoshi
K
Nagae
Tetsuya
T
Makino
Hisashi
H
Suganami
Takayoshi
T
Yahata
Kensei
K
Fujinaga
Yuriko
Y
Tanaka
Issei
I
Nakao
Kazuwa
K
D000199:Actins / Q000032:analysis; D000818:Animals; D002478:Cells, Cultured; D055513:Connective Tissue Growth Factor; D004847:Epithelial Cells / Q000737:chemistry; D005347:Fibroblasts / Q000378:metabolism; D005353:Fibronectins / Q000096:biosynthesis / Q000235:genetics*; D015870:Gene Expression; D006133:Growth Substances / Q000235:genetics / Q000502:physiology*; D017874:Immediate-Early Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D017403:In Situ Hybridization; D036341:Intercellular Signaling Peptides and Proteins; D007678:Kidney Glomerulus / Q000737:chemistry; D007684:Kidney Tubules / Q000737:chemistry; D008297:Male; D009395:Nephritis, Interstitial / Q000503:physiopathology*; D020319:Oligodeoxyribonucleotides, Antisense / Q000235:genetics / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D014162:Transfection; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000494:pharmacology; D053773:Transforming Growth Factor beta1; D014517:Ureteral Obstruction / Q000503:physiopathology
D000199:Actins; C526316:CCN2 protein, rat; D005353:Fibronectins; D006133:Growth Substances; D017874:Immediate-Early Proteins; D036341:Intercellular Signaling Peptides and Proteins; D020319:Oligodeoxyribonucleotides, Antisense; D012333:RNA, Messenger; C508962:Tgfb1 protein, rat; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D055513:Connective Tissue Growth Factor