title: MiR-365: a mechanosensitive microRNA stimulates chondrocyte differentiation through targeting histone deacetylase 4.
abstract: Mechanical stress plays an essential role in tissue development and remodeling. In this study, we determined the role of microRNA in chondrocyte mechanotransduction. Using microarray, we identified miR-365 as a mechanoresponsive microRNA in parallel to mechanical induction of Indian hedgehog (Ihh) in primary chicken chondrocytes cultured in 3-dimensional collagen scaffoldings under cyclic loading (1 Hz, 5% elongation). Interestingly, expression of miR-365 is elevated in the prehypertrophic zone of the growth plate, coinciding with the Ihh expression region in vivo. MiR-365 significantly stimulates chondrocyte proliferation and differentiation. MiR-365 increases expression of Ihh and the hypertrophic marker type X collagen, whereas anti-miR-365 inhibits the expression of these genes. We identified histone deacetylase 4 (HDAC4), an inhibitor of chondrocyte hypertrophy, as a target of miR-365. MiR-365 inhibits both endogenous HDAC4 protein levels as well as the activity of a reporter gene bearing the 3'-untranslated region of HDAC4 mRNA. Conversely, inhibition of endogenous miR-365 relieves the repression of HDAC4. Mutation of the miR-365 binding site in HDAC4 mRNA abolishes miR-365-mediated repression of the reporter gene activity. Overexpression of HDAC4 reverses miR-365 stimulation of chondrocyte differentiation markers including Ihh, Col X, and Runx2. Moreover, inhibition of miR-365 abolishes mechanical stimulation of chondrocyte differentiation. Taken together, miR-365 is the first identified mechanically responsive microRNA that regulates chondrocyte differentiation via directly targeting HDAC4.
authors.affiliation: Cell and Molecular Biology Laboratory, Department of Orthopaedics, Alpert Medical School of Brown University/Rhode Island Hospital, 1 Hoppin St., Ste. 402, Providence, RI 02903, USA.
authors.forename: Ying-Jie
authors.initials: YJ
authors.lastname: Guan
authors.forename: Xu
authors.initials: X
authors.lastname: Yang
authors.forename: Lei
authors.initials: L
authors.lastname: Wei
authors.forename: Qian
authors.initials: Q
authors.lastname: Chen
mesh_terms: D020413:3' Untranslated Regions; D000818:Animals; D030161:Avian Proteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism*; D001483:Base Sequence; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology; D049109:Cell Proliferation; D002478:Cells, Cultured; D002642:Chick Embryo; D019902:Chondrocytes / Q000166:cytology* / Q000378:metabolism*; D020219:Chondrogenesis / Q000235:genetics* / Q000502:physiology*; D017931:DNA Primers / Q000235:genetics; D006655:Histone Deacetylases / Q000235:genetics* / Q000378:metabolism*; D040542:Mechanotransduction, Cellular / Q000235:genetics / Q000502:physiology; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism*; D008954:Models, Biological; D016297:Mutagenesis, Site-Directed
chemical_list: D020413:3' Untranslated Regions; D030161:Avian Proteins; D017931:DNA Primers; D035683:MicroRNAs; D006655:Histone Deacetylases