Down‐regulation of connective tissue growth factor and type I collagen mRNA expression by connective tissue growth factor antisense oligonucleotide during experimental liver fibrosis

Abstract

Transforming growth factor (TGF)-beta 1 is a major mediator of liver fibrosis. Connective tissue growth factor (CTGF) mediates TGF-beta 1 pro-fibrogenic effects in vitro, but its in vivo role is unknown. Both TGF-beta 1 and CTGF are overexpressed in hepatic stellate cells during liver fibrosis. We have used antisense oligonucleotides to examine the role of CTGF in carbon tetrachloride-induced liver fibrosis in mice. Mice received carbon tetrachloride together with CTGF or TGF-beta 1 antisense oligonucleotides for 2 weeks (preventive model), or carbon tetrachloride for 2 weeks followed by carbon tetrachloride and oligonucleotides for 2 more weeks (curative model). In both models, CTGF and TGF-beta 1 oligonucleotides decreased by more than 50 percent the mRNA expression of their targets. Type I collagen mRNA was also decreased by about 40 percent in the preventive experiment. Tissue inhibitor of matrix metalloproteinase-1 mRNA expression and fibrotic deposition evaluated by Sirius red staining were not modified in any group. In summary, our results suggest that hepatic stellate cells can be targeted in vivo with oligonucleotides, and that reducing CTGF levels can lead to a decrease in fibrogenesis as shown by the reduction in type I collagen expression. The lack of effect on fibrosis may be due to the persistence of high tissue inhibitor of matrix metalloproteinase-1 expression.

Increased cAMP Levels Modulate Transforming Growth Factor-β/Smad-induced Expression of Extracellular Matrix Components and Other Key Fibroblast Effector Functions

“…One potential alternative mechanism may reside in transcriptional repression of CTGF. Knockdown of CTGF abolishes collagen deposition in various in vitro and in vivo models (11,29,30,33). We showed that TGF-␤-stimulated CTGF expression is completely abolished by incubation with forskolin.…”

“…Forskolin acts as a repressor of TGF-␤-mediated COL1A1/2 expression, subsequently leading to decreased intracellular and secreted amounts of collagen type I. This modulatory effect might in part be mediated by CTGF, as CTGF inhibition is reported to suppress excessive collagen deposition in various in vitro and in vivo models (11,29,30,33).…”

PPAR gamma inhibits growth of rat hepatic stellate cells and TGF beta-induced connective tissue growth factor expression1

“…CTGF is specifically induced by TGF-β1 and is considered to be the downstream response element and effective molecule of TGF-β1. It has been reported that CTGF is the key regulator of extracellular matrix production and plays an important role in hepatic and renal fibrosis, thus the TGF-β1-CTGF signal pathway might be an effective target for reversal of hepatic fibrosis [9,10] . Peroxisome proliferator-activated receptors (PPAR), including α, β/δ and γ are a family of ligand-activated nuclear transcriptional factors that are emerging as important determinants of cell growth and differentiation [11] .…”

Curcumin suppresses the expression of extracellular matrix genes in activated hepatic stellate cells by inhibiting gene expression of connective tissue growth factor

“…In response to exogenous CTGF, HSCs demonstrate increased migration, proliferation, adhesion, and expression of type I collagen (6,41). Blockade of CTGF synthesis by antisense oligonucleotides of CTGF resulted in downexpression of type I collagen mRNA in an animal model with experimental liver fibrosis (52). Overproduction of CTGF in a variety of fibrotic disorders, including hepatic fibrosis, is presumably secondary to the activation and production of TGF-␤.…”