title: Enhancement of bone morphogenetic protein-2 expression and bone formation by coumarin derivatives via p38 and ERK-dependent pathway in osteoblasts.
abstract: Osteoporosis is a reduction in skeletal mass due to an imbalance between bone resorption and bone formation. Bone morphogenetic protein (BMP) plays important roles in osteoblastic differentiation and bone formation. Therefore, components involved in BMP activation are good targets for the development of anti-osteoporosis drugs. In this study, imperatorin and bergapten, two coumarin derivatives, were shown to enhance alkaline phosphatase (ALP) activity, type I collagen synthesis and bone nodule formation in primary cultured osteoblasts. Imperatorin and bergapten increased mRNA levels of BMP-2 using quantitative RT-PCR, whereas the BMP-2 antagonist noggin attenuated the increase of ALP activity induced by imperatorin and bergapten, indicating that BMP-2 expression is required for the action of imperatorin and bergapten in osteoblastic maturation. Both imperatorin and bergapten enhanced the phosphorylation of SMAD (transcription factors activated by TGF-beta) 1/5/8, p38 and extracellular signal-regulated protein (ERK). Pretreatment of osteoblasts with p38 inhibitor (SB203580) or mitogen-activated protein kinase inhibitor (PD98059) or transfected with dominant negative mutant of p38 or ERK antagonized the elevation of BMP-2 expression and ALP activity induced by imperatorin and bergapten. Local administration of imperatorin or bergapten into the metaphysis of the tibia via the implantation of a needle cannula significantly increased the BMP-2 immunostaining and bone volume of secondary spongiosa in tibia. Taken together, our results provide evidence that coumarin derivatives increase BMP-2 expression and enhance bone formation in rat via the p38 and ERK-dependent signaling pathway.
authors.affiliation: Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Chih-Hsin
authors.initials: CH
authors.lastname: Tang
authors.forename: Rong-Sen
authors.initials: RS
authors.lastname: Yang
authors.forename: Mei-Yin
authors.initials: MY
authors.lastname: Chien
authors.forename: Chien-Chich
authors.initials: CC
authors.lastname: Chen
authors.forename: Wen-Mei
authors.initials: WM
authors.lastname: Fu
mesh_terms: D000078223:5-Methoxypsoralen; D000469:Alkaline Phosphatase / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000187:drug effects* / Q000378:metabolism; D002478:Cells, Cultured; D024042:Collagen Type I / Q000187:drug effects / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000187:drug effects / Q000378:metabolism; D011564:Furocoumarins / Q000494:pharmacology*; D008297:Male; D008730:Methoxsalen / Q000031:analogs & derivatives* / Q000494:pharmacology; D010006:Osteoblasts / Q000187:drug effects* / Q000378:metabolism; D010012:Osteogenesis / Q000187:drug effects*; D010766:Phosphorylation; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051896:Smad Proteins, Receptor-Regulated / Q000187:drug effects / Q000378:metabolism; D013977:Tibia / Q000187:drug effects / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000187:drug effects* / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000187:drug effects / Q000378:metabolism
chemical_list: C525720:Bmp2 protein, rat; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D024042:Collagen Type I; D011564:Furocoumarins; D012333:RNA, Messenger; D051896:Smad Proteins, Receptor-Regulated; D016212:Transforming Growth Factor beta; D000078223:5-Methoxypsoralen; D048049:Extracellular Signal-Regulated MAP Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D000469:Alkaline Phosphatase; C031534:imperatorin; D008730:Methoxsalen