title: Genistein induces oestrogen receptor-α gene expression in osteoblasts through the activation of mitogen-activated protein kinases/NF-κB/activator protein-1 and promotes cell mineralisation.
abstract: Oestrogen and oestrogen receptors (ER) play critical roles in the maintenance of bone remodelling. Genistein, structurally similar to 17β-oestradiol, is a phyto-oestrogen that may be beneficial for treating osteoporosis. In the present study, we evaluated the effects of genistein on the regulation of ERα gene expression and osteoblast mineralisation using MC3T3-E1 cells and primary rat calvarial osteoblasts as our experimental models. Exposure of MC3T3-E1 cells and primary rat osteoblasts to genistein at ≤ 10 μm for 24 h did not affect the cell morphology or viability. However, treatment of MC3T3-E1 cells with 10 μm-genistein enhanced the phosphorylation of extracellular signal-regulated kinase 1/2, p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase 1/2 in a time-dependent manner. Sequentially, genistein increased the translocation of NF-κB and c-Jun from the cytoplasm to the nucleus. Consequently, exposure of MC3T3-E1 cells to genistein induced ERα mRNA expression in concentration- and time-dependent manners. In parallel, the amounts of cytosolic and nuclear ERα in MC3T3-E1 cells were increased following genistein administration. Additionally, genistein also increased the levels of ERα mRNA and nuclear ERα protein in rat calvarial osteoblasts. A bioinformatic search revealed that there are several ERα-specific DNA-binding elements in the 5'-promoter regions of the bone morphogenetic protein-6, collagen type I and osteocalcin genes. As a result, genistein could induce the expressions of these osteoblast differentiation-related genes in primary rat osteoblasts. Co-treatment with genistein and traditional differentiation reagents synergistically increased osteoblast mineralisation. Therefore, the present study showed that genistein can induce ERα gene expression via the activation of MAPK/NF-κB/activator protein-1 and accordingly stimulates differentiation-related gene expressions and osteoblast mineralisation.
authors.affiliation: College of Medicine, Graduate Institute of Medical Sciences, Taipei Medical University, 250 Wu-Xing Street, Taipei 110, Taiwan.
authors.forename: Mei-Hsiu
authors.initials: MH
authors.lastname: Liao
authors.affiliation: Cell Physiology and Molecular Image Research Center, Taipei Medical University-Wan Fang Hospital, Taipei, Taiwan.
authors.forename: Yu-Ting
authors.initials: YT
authors.lastname: Tai
authors.affiliation: Department of Anesthesiology, Shuang-Ho Hospital, Taipei Medical University, Taipei, Taiwan.
authors.forename: Yih-Giun
authors.initials: YG
authors.lastname: Cherng
authors.affiliation: College of Medicine, Institute of Toxicology, National Taiwan University, Taipei, Taiwan.
authors.forename: Shing-Hwa
authors.initials: SH
authors.lastname: Liu
authors.affiliation: Cell Physiology and Molecular Image Research Center, Taipei Medical University-Wan Fang Hospital, Taipei, Taiwan.
authors.forename: Ya-An
authors.initials: YA
authors.lastname: Chang
authors.affiliation: College of Medicine, Graduate Institute of Medical Sciences, Taipei Medical University, 250 Wu-Xing Street, Taipei 110, Taiwan.
authors.forename: Pei-I
authors.initials: PI
authors.lastname: Lin
authors.affiliation: College of Medicine, Graduate Institute of Medical Sciences, Taipei Medical University, 250 Wu-Xing Street, Taipei 110, Taiwan.
authors.forename: Ruei-Ming
authors.initials: RM
authors.lastname: Chen
mesh_terms: D016475:3T3 Cells; D000818:Animals; D055418:Bone Morphogenetic Protein 6 / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics; D024042:Collagen Type I / Q000235:genetics / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D047628:Estrogen Receptor alpha / Q000235:genetics* / Q000378:metabolism; D007887:Fabaceae / Q000737:chemistry; D015870:Gene Expression / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D019833:Genistein / Q000494:pharmacology*; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D010006:Osteoblasts / Q000187:drug effects* / Q000378:metabolism; D015675:Osteocalcin / Q000235:genetics / Q000378:metabolism; D010012:Osteogenesis / Q000187:drug effects* / Q000235:genetics; D010766:Phosphorylation; D048789:Phytoestrogens / Q000494:pharmacology; D010936:Plant Extracts / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D018808:Transcription Factor AP-1 / Q000378:metabolism*
chemical_list: D055418:Bone Morphogenetic Protein 6; D024042:Collagen Type I; D047628:Estrogen Receptor alpha; D016328:NF-kappa B; D048789:Phytoestrogens; D010936:Plant Extracts; D012333:RNA, Messenger; D018808:Transcription Factor AP-1; D015675:Osteocalcin; D019833:Genistein; D020928:Mitogen-Activated Protein Kinases