title: Estrogen receptor mediates simvastatin-stimulated osteogenic effects in bone marrow mesenchymal stem cells.
abstract: Simvastatin, an HMG-CoA reductase inhibitor, is known to promote osteogenic differentiation. However, the mechanism underlying simvastatin-induced osteogenesis is not well understood. In this study, we hypothesize that the estrogen receptor (ER) mediates simvastatin-induced osteogenic differentiation. ER antagonists and siRNA were used to determine the involvement of the ER in simvastatin-induced osteogenesis in mouse bone marrow mesenchymal stem cells (D1 cells). Osteogenesis was evaluated by mRNA expression, protein level/activity of osteogenic markers, and mineralization. The estrogen response element (ERE) promoter activity and the ER-simvastatin binding affinity were examined. Our results showed that the simvastatin-induced osteogenic effects were decreased by treatment with ERα antagonists and ERα siRNA but not by an antagonist specific for the G protein-coupled estrogen receptor (GPER-1). The simvastatin-induced osteogenic effects were further increased by E2 treatment and were reversed by ERα antagonists or siRNA treatment. Luciferase reporter gene assays demonstrated that simvastatin increase ERα-dependent transcriptional activity that was suppressed by ERα antagonists. Furthermore, the ERα-simvastatin binding assay showed that IC50 value of simvastatin is 7.85 μM and that of E2 is 32.8 nM, indicating that simvastatin is a weak ligand for ERα. These results suggest that simvastatin-stimulated osteogenesis is mediated by ERα but not GPER-1. Moreover, this is the first report to demonstrate that simvastatin acts as an ERα ligand and a co-activator to enhance ERα-dependent transcriptional activity and thus promotes osteogenesis. These results indicate that simvastatin-induced osteogenesis is mediated via an ERα-dependent pathway.
authors.affiliation: Orthopedic Research Center, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Shu-Chun
authors.initials: SC
authors.lastname: Chuang
authors.affiliation: Orthopedic Research Center, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Orthopedics, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Orthopedics, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Orthopedics, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Chung-Hwan
authors.initials: CH
authors.lastname: Chen
authors.affiliation: Orthopedic Research Center, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Orthopedics, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Orthopedics, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Orthopedics, Kaohsiung Municipal Hsiao-Kang Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Yin-Chin
authors.initials: YC
authors.lastname: Fu
authors.affiliation: Orthopedic Research Center, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Physiology, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: I-Chun
authors.initials: IC
authors.lastname: Tai
authors.affiliation: Orthopedic Research Center, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Ching-Ju
authors.initials: CJ
authors.lastname: Li
authors.affiliation: Orthopedic Research Center, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Li-Fu
authors.initials: LF
authors.lastname: Chang
authors.affiliation: Orthopedic Research Center, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Physiology, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung, Taiwan. Electronic address: homelin@kmu.edu.tw.
authors.forename: Mei-Ling
authors.initials: ML
authors.lastname: Ho
authors.affiliation: Orthopedic Research Center, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Orthopedics, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Orthopedics, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Orthopedics, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan. Electronic address: jkchang@kmu.edu.tw.
authors.forename: Je-Ken
authors.initials: JK
authors.lastname: Chang
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects*; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D004958:Estradiol / Q000494:pharmacology*; D004965:Estrogen Antagonists / Q000494:pharmacology; D047628:Estrogen Receptor alpha / Q000502:physiology*; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000187:drug effects*; D051379:Mice; D019821:Simvastatin / Q000494:pharmacology*
chemical_list: D004965:Estrogen Antagonists; D047628:Estrogen Receptor alpha; D004958:Estradiol; D019821:Simvastatin
keywords: Estrogen receptor; Estrogen response element; Mesenchymal stem cells; Osteogenesis; Simvastatin