[Effect of small interfering RNA-mediated Smad3 gene silencing on transforming growth factor-beta1-induced bi-directional effects on skin fibroblast proliferation].

Objective: To study the role of Smad3 in transforming growth factor-beta1 (TGF-beta1)-induced bi-directional effects on skin fibroblast proliferation.

Methods: The Smad3 small interfering (siRNA) plasmid was constructed using a pSUPER vector. The efficiency of cell transfection was detected by fluorescence microscopy, and the inhibitory effect of the plasmid was assessed by real-time quantitative RT-PCR and immunohistochemistry. The effect of the plasmid on the fibroblast proliferation and Smad3 binding activity was analyzed by BRDU ELISA and EMSA, respectively.

Results: The transfection efficiency of the plasmid into the cells was 41.2%. The Smad3 siRNA plasmid produced efficient and specific inhibition of the expression of Smad3, and promoted the cell proliferation in a dose-dependent manner and abrogated the bi-directional effect of TGF-beta1 on the cell proliferation and Smad3 binding activity.

Conclusion: The siRNA targeting Smad3 gene can inhibit the protein expression and RNA transcription of Smad3, and TGF-beta1 exerts bi-directional regulation on fibroblast proliferation by modulating Smad3 activity.