Lycium barbarum polysaccharides promote osteoblasts viability by regulating microRNA-17/PTEN.

Lycium barbarum polysaccharides (LBPs) have been reported to promote the proliferation of osteoblasts. Further, the proliferation of osteoblasts has been proved to be associated with microRNA (miR)-17 which targets phosphatase and tensin homolog (PTEN) 3'-untranslated region (UTR) for regulating phosphoinositide 3 kinase/protein kinase B (PI3K/AKT) signaling pathway. Consequently, we aimed to explore a miR-17-relative mechanism by which LBPs mediates proliferation of osteoblasts.LBPs were used to stimulate MC3T3-E1 cells, and SF1670 was applied to repress PTEN. miR-17 inhibitor was transfected into cells for down-regulating miR-17. The cell viability and migration were examined by cell counting kit-8 (CCK-8) and 24-well Transwell migration assay, respectively. The expression of Cyclin D1, matrix metallopeptidase (MMP)-2 and MMP-9 was analyzed using Western blot. Quantitative reverse transcription PCR (qRT-PCR) was conducted to detect miR-17. The expression of PTEN and phosphorylation of PI3K and AKT were analyzed by Western blot.We demonstrated that LBPs promoted osteoblasts viability, facilitated migration and positively regulated the expression of miR-17. Additionally, miR-17 inhibitor abolished the positive effects of LBPs on the osteoblasts. Molecularly, miR-17 inhibited the expression of PTEN by targeting its 3'-untranslated region (3'-UTR). Mechanically, LBPs diminished PTEN expression and facilitated the phosphorylation of PI3K and AKT, while the decreased expression of PTEN and enhanced phosphorylation of PI3K and AKT were reversed by miR-17 inhibitor.LBPs might fortify osteoblasts viability by up-regulating miR-17 to target PTEN and consequently trigger PI3K/AKT pathway.