title: MicroRNA-21 promotes osteogenic differentiation by targeting small mothers against decapentaplegic 7.
abstract: Previous studies have suggested that microRNAs (miRNAs/miRs) may positively or negatively control osteogenic differentiation and mineralization by targeting negative regulators of osteogenesis or important osteogenic factors. miR-21 is important in osteoblast differentiation and Smad7 is a critical regulator of osteogenic differentiation, which inhibits proliferation, differentiation and mineralization in mouse osteoblast cells. However, the association between Smad7 and miR-21 remain to be elucidated. In the present study, miR-21 was found to promote the level of osteogenic differentiation and increase matrix mineralization in MC3T3-E1 cells. Furthermore, Smad7 was identified as a direct target of miR-21 in the MC3T3-E1 cells. The overexpression of miR-21 affected the protein levels of SMAD7, but not the mRNA levels, which suggested that miR-21 regulates the levels of SMAD7 by inhibiting translation, rather than by promoting mRNA decay. Forced expression of miR-21 promoted osteogenic differentiation and mineralization, while inhibition of miR-21 suppressed these processes. The present study also identified for the first time, to the best of our knowledge, the promotion of osteogenic differentiation and mineralization by miR-21, by repressing the expression of Smad7.
authors: Department of Orthopedics, Shengjing Hospital of China Medical University, Shenyang 110004, P.R. China.
authors: Hongqiu
authors: H
authors: Li
authors: Department of Radiology, Central Hospital of Shenyang Medical College, Shenyang 110024, P.R. China.
authors: Feng
authors: F
authors: Yang
authors: Department of Blood Transfusion, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China.
authors: Zhe
authors: Z
authors: Wang
authors: Department of Orthopedics, Shengjing Hospital of China Medical University, Shenyang 110004, P.R. China.
authors: Qin
authors: Q
authors: Fu
authors: Department of Orthopedics, Central Hospital of Shenyang Medical College, Shenyang 110024, P.R. China.
authors: A
authors: A
authors: Liang
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D059630:Mesenchymal Stem Cells; D051379:Mice; D035683:MicroRNAs / Q000096:biosynthesis* / Q000235:genetics; D010006:Osteoblasts / Q000378:metabolism; D010012:Osteogenesis / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis; D051906:Smad7 Protein / Q000096:biosynthesis* / Q000235:genetics
chemical_list: C531950:MIRN21 microRNA, mouse; D035683:MicroRNAs; D012333:RNA, Messenger; D051906:Smad7 Protein; C497807:Smad7 protein, mouse