title: Effects of a miR-31, Runx2, and Satb2 regulatory loop on the osteogenic differentiation of bone mesenchymal stem cells.
abstract: Recently, a cohort of miRNAs, including miR-31, was reported to be downregulated during osteogenic induction by miR microarray analysis. It remains unclear how changes in miR-31 expression collaborate with bone transcription factors to activate the biological pathways that regulate the differentiation of bone mesenchymal stem cells (BMSCs). Here the effects of miR-31, Runx2, and Satb2 on the osteogenic differentiation of BMSCs were investigated using mimics and inhibitors of miR-31, small interfering RNA for knockdown of Runx2 and plasmids for overexpression of Runx2. Our results showed that miR-31 expression decreased progressively in BMSC cultures during differentiation. Inhibition of miR-31 dramatically increased the alkaline phosphatase activity and mineralization in BMSC cultures. Additionally, miR-31 diminished the levels of the Satb2 protein without significantly affecting Satb2 mRNA levels, and Runx2 directly repressed miR-31 expression. Overexpression of miR-31 significantly reduced expression of the osteogenic transcription factors OPN, BSP, OSX, and OCN, but not Runx2. Furthermore, the high expression of miR-31 in BMSCs cultured in the proliferation medium repressed Satb2 protein levels, which may contribute to the maintenance of BMSCs in an undifferentiated state. In conclusion, our results suggest that a Runx2, Satb2, and miR-31 regulatory mechanism may play an important role in inducing BMSC osteogenic differentiation. The results of this study provide us with a better understanding of the molecular mechanisms that govern the BMSC fate.
authors.affiliation: Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Deng
authors.forename: Si
authors.initials: S
authors.lastname: Wu
authors.forename: Huifang
authors.initials: H
authors.lastname: Zhou
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Bi
authors.forename: Yefei
authors.initials: Y
authors.lastname: Wang
authors.forename: Yamin
authors.initials: Y
authors.lastname: Hu
authors.forename: Ping
authors.initials: P
authors.lastname: Gu
authors.forename: Xianqun
authors.initials: X
authors.lastname: Fan
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology / Q000378:metabolism*; D002454:Cell Differentiation; D002460:Cell Line; D050659:Core Binding Factor Alpha 1 Subunit / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D005269:Femur / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D008297:Male; D036961:Matrix Attachment Region Binding Proteins / Q000235:genetics / Q000378:metabolism*; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D010012:Osteogenesis / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction; D013977:Tibia / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D050659:Core Binding Factor Alpha 1 Subunit; C570112:MIRN31 microRNA, rat; D036961:Matrix Attachment Region Binding Proteins; D035683:MicroRNAs; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C493717:Runx2 protein, rat; C501473:SATB2 protein, mouse; C586446:SATB2 protein, rat; D014157:Transcription Factors