title: Myricetin induces human osteoblast differentiation through bone morphogenetic protein-2/p38 mitogen-activated protein kinase pathway.
abstract: Myricetin (3,3',4',5,5',7-hexahydroxyflavone), a flavonoid compound, is present in vegetables and fruits. By means of alkaline phosphatase (ALP) activity, osteocalcin, and type I collagen enzyme-linked immunosorbent assay (ELISA), we have shown that myricetin exhibits a significant induction of differentiation in MG-63 and hFOB human osteoblasts. Alkaline phosphatase and osteocalcin are phenotypic markers for early-stage differentiated osteoblasts and terminally differentiated osteoblasts, respectively. Our results indicate that myricetin stimulates osteoblast differentiation at various stages, from maturation to terminally differentiated osteoblasts. Induction of differentiation by myricetin is associated with increased bone morphogenetic protein-2 (BMP-2) production. The BMP-2 antagonist noggin blocked myricetin-mediated ALP activity and osteocalcin secretion enhancement, indicating that BMP-2 production is required in myricetin-mediated osteoblast maturation and differentiation. Induction of differentiation by myricetin is associated with increased activation of SMAD1/5/8 and p38 mitogen-activated protein kinases. Cotreatment of p38 inhibitor SB203580 inhibited myricetin-mediated ALP upregulation and osteocalcin production. In conclusion, myricetin increased BMP-2 synthesis, and subsequently activated SMAD1/5/8 and p38 MAPK, and this effect may contribute to its action on the induction of osteoblast maturation and differentiation, followed by an increase of bone mass.
authors.affiliation: Department of Pharmacy, Chia-Nan University of Pharmacy and Science, Tainan, Taiwan.
authors.forename: Ya-Ling
authors.initials: YL
authors.lastname: Hsu
authors.forename: Jiunn-Kae
authors.initials: JK
authors.lastname: Chang
authors.forename: Chu-Hung
authors.initials: CH
authors.lastname: Tsai
authors.forename: Tzu-Tsung Chang
authors.initials: TT
authors.lastname: Chien
authors.forename: Po-Lin
authors.initials: PL
authors.lastname: Kuo
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D001324:Autoantigens / Q000378:metabolism; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000378:metabolism*; D002352:Carrier Proteins / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects*; D002460:Cell Line; D045744:Cell Line, Tumor; D024042:Collagen Type I / Q000378:metabolism; D003513:Cycloheximide / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D005419:Flavonoids / Q000494:pharmacology*; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D015675:Osteocalcin / Q000378:metabolism; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D017411:Ribonucleoproteins, Small Nuclear / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D051902:Smad5 Protein / Q000378:metabolism; D051904:Smad8 Protein / Q000378:metabolism; D013997:Time Factors; D016212:Transforming Growth Factor beta / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D055517:snRNP Core Proteins; D000099176:Noggin Protein
chemical_list: D000469:Alkaline Phosphatase; D001324:Autoantigens; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D002352:Carrier Proteins; D024042:Collagen Type I; D003513:Cycloheximide; D004791:Enzyme Inhibitors; D005419:Flavonoids; D007093:Imidazoles; D015675:Osteocalcin; D011500:Protein Synthesis Inhibitors; D011725:Pyridines; D017411:Ribonucleoproteins, Small Nuclear; D051902:Smad5 Protein; D051904:Smad8 Protein; D016212:Transforming Growth Factor beta; D048051:p38 Mitogen-Activated Protein Kinases; D055517:snRNP Core Proteins; D000099176:Noggin Protein; C525718:BMP2 protein, human; C040015:myricetin; C093642:SB 203580