Expression and regulation of connective tissue growth factor by transforming growth factor beta and tumour necrosis factor alpha in fibroblasts isolated from strictures in patients with Crohn's disease.
BACKGROUND
Connective tissue growth factor (CTGF) stimulates fibroblast proliferation and extracellular matrix production. Fibroblasts may initiate stricture formation in Crohn's disease through overexpression of CTGF. Stricturing that occurs in patients with Crohn's disease after treatment with anti-tumour necrosis factor (TNF) alpha may be due to dysregulation of CTGF homeostasis. The aim of this study was to examine CTGF expression and regulation in fibroblasts isolated from patients with Crohn's disease.


METHODS
Fibroblasts were isolated by a primary explant technique from serosal biopsies of strictured segments of bowel in eight patients undergoing resection for Crohn's disease and from normal colon in seven patients having resection for benign or malignant colorectal disease. Cells were stimulated with transforming growth factor (TGF) beta and TNF-alpha. CTGF protein and mRNA expression were measured by western blotting and real-time polymerase chain reaction respectively.


RESULTS
Mean(s.d.) CTGF protein expression in strictured Crohn's fibroblasts was higher than that in normal fibroblasts (56.5(9.7) versus 17.0(10.0) respectively; P = 0.011). In normal and strictured Crohn's fibroblasts, culture with TGF-beta increased CTGF protein and mRNA expression. Co-culture of normal fibroblasts with TNF-alpha suppressed TGF-beta-stimulated CTGF expression.


CONCLUSIONS
: Increased expression of CTGF in strictured Crohn's fibroblasts underlies its role in fibrosis. TNF-alpha suppresses fibrosis by downregulating fibroblast CTGF expression, an effect that may be lost following anti-TNF-alpha treatment, thereby promoting stricture formation.
Beddy
D
D
Department of Surgery, Mater Misericordiae University Hospital and Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Ireland.
Mulsow
J
J
Watson
R W G
RW
Fitzpatrick
J M
JM
O'Connell
P R
PR
D000328:Adult; D000368:Aged; D015153:Blotting, Western; D055513:Connective Tissue Growth Factor; D003424:Crohn Disease / Q000378:metabolism*; D005347:Fibroblasts / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D017874:Immediate-Early Proteins / Q000187:drug effects* / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D008875:Middle Aged; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000009:adverse effects / Q000494:pharmacology*
C526317:CCN2 protein, human; D017874:Immediate-Early Proteins; D036341:Intercellular Signaling Peptides and Proteins; D016212:Transforming Growth Factor beta; D014409:Tumor Necrosis Factor-alpha; D055513:Connective Tissue Growth Factor