Puerarin promotes the viability and differentiation of MC3T3-E1 cells by miR-204-regulated Runx2 upregulation

Puerarin has attracted increasing attention because of its beneficial effects on anti-osteoporosis, but the molecular mechanisms underlying its actions on osteoblasts are not fully understood. The current study aimed to investigate the effect of puerarin on the cell viability and differentiation of mouse MC3T3-E1 osteoblast-like cells in vitro and its underlying mechanisms. The results indicated that 0.01, 0.1 and 1 mg/ml puerarin significantly promoted the viability of osteoblasts, enhanced alkaline phosphatase (ALP) activity and increased the expression of transforming growth factor-beta 1, Smad2, Smad3 and Runt-related transcription factor (Runx)2. Micro (mi)RNA target prediction programs predicted that miR-204 may directly target Runx2. Following treatment with 0.1 mg/ml puerarin for 48 h, the expression level of miR-204 was down-regulated. Besides, miR-204 dramatically repressed the luciferase activity of wildtype Runx2 3 '-UTR transfected cells, but not that of the mutant ones. Overexpression of miR-204 in osteoblasts significantly decreased the protein expression of Runx2, while inhibition of miR-204 enhanced Runx2' s expression. In addition, overexpression of miR-204 inhibited the cell viability and ALP activity of osteoblasts, while inhibition of miR-204 had the opposite effect. The results suggested that puerarin may promote MC3T3-E1 osteoblast-like cell viability and differentiation, which may be related to the downregulation of miR-204 and the following activation of Runx2.