Abstract: Objective To investigate the effect of lysine methyltransferase SET8 on regulating cell transdifferentiation of rat vascular smooth muscle cells (VSMCs) into osteoblast-like cells. Methods VSMCs were obtained from rat thoracic aorta, and then randomly divided into control group (non-transfection), the empty plasmid group (transfect NS-shRNA) and SET8-shRNA group. The expression of SET8, runt⁃related transcription factor 2 (RUNX2) was detected by RT⁃PCR and Western blot assay. Alkaline phosphatase (ALP) activity was measured by enzyme linked immunoassay. Results The expression of SET8 in VSMCs was effectively inhibited by SET8-shRNA. RT-PCR and Western blot results showed that the expression of RUNX2 was decreased in cells after SET8-shRNA transfection (P＜0.05). ALP activity was significantly reduced after SET8-shRNA transfection (P＜0.05). Conclusion Interference with SET8 gene expression could inhibit the differentiation of VSMCs into osteo-like cells.

Key words: myocytes, smooth muscle, cell transdifferentiation, histone-lysine n-methyltransferase, RNA interference, alkaline phosphatase, lysine methyhransferase SET8, RUNX2