Inhibition of Growth of Human Gingival Fibroblasts by Chimeric DNA‐RNA Hammerhead Ribozyme Targeting Transforming Growth Factor‐β1

Abstract

Background: Transforming growth factor (TGF)‐β1 is involved in the pathogenesis of both drug‐induced gingival overgrowth and hereditary gingival fibromatosis. Ribozymes enzymatically cleave target mRNAs and are expected to be utilized as the basis of novel nucleic acid‐based therapies. We designed a chimeric DNA‐RNA ribozyme targeting TGF‐β1 mRNA and examined its effect on growth of gingival fibroblasts in culture. Methods: Chimeric DNA‐RNA hammerhead ribozyme with sequence complementary to the loop structure of human TGF‐β1 mRNA was used. We evaluated transfer of the chimeric ribozyme by hemagglutinating virus of Japan (HVJ)‐envelope into cultured human gingival fibroblasts in vitro and rat gingival tissues in vivo. We then examined effects of the chimeric ribozyme to TGF‐β1 on proliferation and DNA synthesis in human gingival fibroblasts. We also examined effects of the chimeric ribozyme to TGF‐β1 on expression of TGF‐β1, type IV collagens, and fibronectin mRNAs and expression of TGF‐β1 protein in human gingival fibroblasts. Results: Chimeric ribozyme was sufficiently distributed into human fibroblasts in vitro and rat gingivae in vivo. Chimeric ribozyme to TGF‐β1 significantly inhibited expression of TGF‐β1, type IV collagen, and fibronectin mRNAs and TGF‐β1 protein in human gingival fibroblasts. Mismatch ribozyme had no effect on expression of these molecules. Chimeric ribozyme to TGF‐β1 also significantly inhibited proliferation and DNA synthesis in gingival fibroblasts. Conclusion: Chimeric DNA‐RNA ribozyme targeting TGF‐β1 may be a useful gene therapy agent for treatment of gingival hyperplasia. J Periodontol 2005;76:1265‐1274 .