title: MicroRNA-145 regulates chondrogenic differentiation of mesenchymal stem cells by targeting Sox9.
abstract: Chondrogenic differentiation of mesenchymal stem cells (MSCs) is accurately regulated by essential transcription factors and signaling cascades. However, the precise mechanisms involved in this process still remain to be defined. MicroRNAs (miRNAs) regulate various biological processes by binding target mRNA to attenuate protein synthesis. To investigate the mechanisms for miRNAs-mediated regulation of chondrogenic differentiation, we identified that miR-145 was decreased during transforming growth factor beta 3 (TGF-β3)-induced chondrogenic differentiation of murine MSCs. Subsequently, dual-luciferase reporter gene assay data demonstrated that miR-145 targets a putative binding site in the 3'-UTR of SRY-related high mobility group-Box gene 9 (Sox9) gene, the key transcription factor for chondrogenesis. In addition, over-expression of miR-145 decreased expression of Sox9 only at protein levels and miR-145 inhibition significantly elevated Sox9 protein levels. Furthermore, over-expression of miR-145 decreased mRNA levels for three chondrogenic marker genes, type II collagen (Col2a1), aggrecan (Agc1), cartilage oligomeric matrix protein (COMP), type IX collagen (Col9a2) and type XI collagen (Col11a1) in C3H10T1/2 cells induced by TGF-β3, whereas anti-miR-145 inhibitor increased the expression of these chondrogenic marker genes. Thus, our studies demonstrated that miR-145 is a key negative regulator of chondrogenic differentiation by directly targeting Sox9 at early stage of chondrogenic differentiation.
authors.affiliation: Laboratory of Biomechanics, Department of Anatomy, The Third Military Medical University, Chongqing, People's Republic of China.
authors.forename: Bo
authors.initials: B
authors.lastname: Yang
authors.forename: Hongfeng
authors.initials: H
authors.lastname: Guo
authors.forename: Yulan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Lei
authors.initials: L
authors.lastname: Chen
authors.forename: Dajun
authors.initials: D
authors.lastname: Ying
authors.forename: Shiwu
authors.initials: S
authors.lastname: Dong
mesh_terms: D020413:3' Untranslated Regions / Q000235:genetics; D000818:Animals; D001483:Base Sequence; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics*; D002460:Cell Line; D020219:Chondrogenesis / Q000187:drug effects / Q000235:genetics*; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics; D017930:Genes, Reporter / Q000235:genetics; D008156:Luciferases / Q000235:genetics; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D055758:SOX9 Transcription Factor / Q000235:genetics* / Q000378:metabolism; D053782:Transforming Growth Factor beta3 / Q000494:pharmacology
chemical_list: D020413:3' Untranslated Regions; C543499:MIRN145a microRNA, mouse; D035683:MicroRNAs; D055758:SOX9 Transcription Factor; C527933:Sox9 protein, mouse; D053782:Transforming Growth Factor beta3; D008156:Luciferases