title: Myocyte enhancer factor 2c, an osteoblast transcription factor identified by dimethyl sulfoxide (DMSO)-enhanced mineralization.
abstract: Rapid mineralization of cultured osteoblasts could be a useful characteristic in stem cell-mediated therapies for fracture and other orthopedic problems. Dimethyl sulfoxide (DMSO) is a small amphipathic solvent molecule capable of stimulating cell differentiation. We report that, in primary human osteoblasts, DMSO dose-dependently enhanced the expression of osteoblast differentiation markers alkaline phosphatase activity and extracellular matrix mineralization. Furthermore, similar DMSO-mediated mineralization enhancement was observed in primary osteoblast-like cells differentiated from mouse mesenchymal cells derived from fat, a promising source of starter cells for cell-based therapy. Using a convenient mouse pre-osteoblast model cell line MC3T3-E1, we further investigated this phenomenon showing that numerous osteoblast-expressed genes were elevated in response to DMSO treatment and correlated with enhanced mineralization. Myocyte enhancer factor 2c (Mef2c) was identified as the transcription factor most induced by DMSO, among the numerous DMSO-induced genes, suggesting a role for Mef2c in osteoblast gene regulation. Immunohistochemistry confirmed expression of Mef2c in osteoblast-like cells in mouse mandible, cortical, and trabecular bone. shRNAi-mediated Mef2c gene silencing resulted in defective osteoblast differentiation, decreased alkaline phosphatase activity, and matrix mineralization and knockdown of osteoblast specific gene expression, including osteocalcin and bone sialoprotein. A flow on knockdown of bone-specific transcription factors, Runx2 and osterix by shRNAi knockdown of Mef2c, suggests that Mef2c lies upstream of these two important factors in the cascade of gene expression in osteoblasts.
authors.affiliation: School of Medical Science, Griffith University, Gold Coast Campus, Queensland, Australia.
authors.forename: Alexandre S
authors.initials: AS
authors.lastname: Stephens
authors.forename: Sebastien R
authors.initials: SR
authors.lastname: Stephens
authors.forename: Carl
authors.initials: C
authors.lastname: Hobbs
authors.forename: Deitmar W
authors.initials: DW
authors.lastname: Hutmacher
authors.forename: Desa
authors.initials: D
authors.lastname: Bacic-Welsh
authors.forename: Maria Ann
authors.initials: MA
authors.lastname: Woodruff
authors.forename: Nigel A
authors.initials: NA
authors.lastname: Morrison
mesh_terms: D000818:Animals; D002113:Calcification, Physiologic / Q000187:drug effects* / Q000502:physiology; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D050659:Core Binding Factor Alpha 1 Subunit / Q000235:genetics / Q000378:metabolism; D003451:Cryoprotective Agents / Q000493:pharmacokinetics*; D004121:Dimethyl Sulfoxide / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D020868:Gene Silencing; D006801:Humans; D026161:MADS Domain Proteins / Q000235:genetics / Q000378:metabolism*; D064326:MEF2 Transcription Factors; D051379:Mice; D018006:Myogenic Regulatory Factors / Q000235:genetics / Q000378:metabolism*; D009928:Organ Specificity / Q000187:drug effects / Q000502:physiology; D010006:Osteoblasts / Q000378:metabolism*; D000076182:Sp7 Transcription Factor; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects / Q000502:physiology
chemical_list: D050659:Core Binding Factor Alpha 1 Subunit; D003451:Cryoprotective Agents; D026161:MADS Domain Proteins; D064326:MEF2 Transcription Factors; C578040:MEF2C protein, human; C578041:Mef2c protein, mouse; D018006:Myogenic Regulatory Factors; C493709:RUNX2 protein, human; C493716:Runx2 protein, mouse; D000076182:Sp7 Transcription Factor; C478163:SP7 protein, human; C479466:Sp7 protein, mouse; D014157:Transcription Factors; D004121:Dimethyl Sulfoxide