RESUMO
BACKGROUND: Systemic sclerosis (SSc) is characterized by fibrosis of the skin and internal organs. Although transforming growth factor (TGF)-ß1-induced connective tissue growth factor (CTGF/CCN2) expression has been presented in SSc fibrosis, the therapeutic potential of targeting CTGF in SSc has not been fully explored. COA-Cl is a novel nucleic acid analog, which is reported to have pleiotropic beneficial biologic effects. OBJECTIVE: We examine the effects of COA-Cl on TGF-ß1-induced CTGF expression in normal human dermal fibroblast (NHDF). We also examined the effects of COA-Cl on CTGF expression in a mouse SSc model of angiotensin II (Ang II)-induced skin fibrosis. METHODS: NHDF was cultured for in vitro experiments. For in vivo experiments, C57BL/6J mice were treated with Ang II for 14 days by subcutaneous osmotic pump. Quantitative real-time polymerase chain reaction, western blot analysis, immunohistochemical staining and immunofluorescence staining were performed to examine the expression levels of CTGF and phosphorylation levels of Smad2/3, ERK1/2 and Akt. RESULTS: COA-Cl attenuated the TGF-ß1-induced expression of both CTGF mRNA and protein in NHDF. Although COA-Cl did not alter the TGF-ß1-induced phosphorylation of Smad2/3 or ERK1/2, it reduced the TGF-ß1-induced phosphorylation levels of Akt in NHDF. Notably, COA-Cl dephosphorylated the Akt of lysates of TGF-ß1-treated NHDF. COA-Cl reduced the levels of CTGF mRNA, CTGF protein, dermal thickness, collagen content and Akt phosphorylation in the skin of mice SSc model. CONCLUSION: These results imply that the inhibition of TGF-ß1-induced CTGF expression by COA-Cl may be a therapeutic approach for SSc.