MicroRNA-205 regulates the calcification and osteoblastic differentiation of vascular smooth muscle cells.

OBJECTIVES: We investigated the role of miR-205 in the osteogenic differentiation of vascular smooth muscle cells (VSMCs).

METHODS: Osteogenic differentiation of human aortic smooth muscle cells (HASMCs) was induced by 10 mM β-glycerophosphate (β-GP). Alizarin Red S staining, alkaline phosphatase (ALP) activity and osteocalcin secretion were used to determine osteogenic differentiation of HASMCs. Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) was used to measure the expression of miR-205 in HASMCs.

RESULTS: The expression of endogenous miR-205 was decreased in HASMCs during β-glycerophosphate-induced calcification. Overexpression of miR-205 inhibited the differentiation of HASMCs into osteoblast-like cells, as evidenced by a decrease in ALP activity, osteocalcin secretion, and Runx2 expression, whereas miR-205 depletion enhanced osteoblastic differentiation of HASMCs. Runx2 and Smad1 were identified as direct targets of miR-205 by computational analysis and experimental assays.

CONCLUSION: The present study shows that miR-205 may negatively regulate the β-glycerophosphate-induced calcification of HASMCs, at least partially by targeting Runx2 and Smad1.