title: RNA interference of the BMPR-IB gene blocks BMP-2-induced osteogenic gene expression in human bone cells.
abstract: We have previously shown that human bone cells express bone morphogenetic protein receptor-IB (BMPR-IB). However, little is known about the precise role of this receptor in the response of osteoblastic genes to the BMP in these cells. To determine BMPR-IB-dependent osteoblastic gene expression, the present study examined the effects of BMPR-IB knockdown on BMP-induced osteoblast-associated genes. BMPR-IB mRNA and protein were markedly suppressed by transfection of cells with BMPR-IB siRNA. Using three different bone cell samples, BMP-2 stimulation of alkaline phosphatase (ALP), osteocalcin (OC), distal-less homeobox-5 (Dlx5) and core binding factor alpha-1 (Cbfa1) was found to be specifically and significantly reduced in the BMPR-IB siRNA-transfected cultures compared with that of control cultures. Our study has provided evidence that BMPR-IB-dependent signaling plays a crucial role in BMP-2 up-regulation of the ALP, OC, Dlx5 and Cbfa1 genes in bone cells, suggesting a pivotal role of this receptor in BMP-2-induced osteoblast differentiation in vitro. These findings thus suggest the possibility that BMPR-IB could be a therapeutic target for enhancing bone regeneration in vivo.
authors.affiliation: Division of Biomaterials and Tissue Engineering, Eastman Dental Institute, University College London, London, UK.
authors.forename: W
authors.initials: W
authors.lastname: Singhatanadgit
authors.forename: V
authors.initials: V
authors.lastname: Salih
authors.forename: I
authors.initials: I
authors.lastname: Olsen
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D001846:Bone Development / Q000187:drug effects / Q000235:genetics*; D055396:Bone Morphogenetic Protein 2 / Q000378:metabolism* / Q000494:pharmacology; D052005:Bone Morphogenetic Protein Receptors, Type I / Q000235:genetics* / Q000378:metabolism; D001861:Bone Regeneration / Q000235:genetics; D002454:Cell Differentiation / Q000235:genetics; D002478:Cells, Cultured; D050659:Core Binding Factor Alpha 1 Subunit / Q000378:metabolism; D015536:Down-Regulation / Q000235:genetics; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects / Q000235:genetics*; D018398:Homeodomain Proteins / Q000378:metabolism; D006801:Humans; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D015675:Osteocalcin / Q000378:metabolism; D010012:Osteogenesis / Q000187:drug effects / Q000235:genetics*; D034622:RNA Interference / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D014157:Transcription Factors / Q000378:metabolism; D014162:Transfection / Q000379:methods; D015854:Up-Regulation / Q000235:genetics
chemical_list: C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2; D050659:Core Binding Factor Alpha 1 Subunit; C100596:DLX5 protein, human; D018398:Homeodomain Proteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D014157:Transcription Factors; D015675:Osteocalcin; D052005:Bone Morphogenetic Protein Receptors, Type I; D000469:Alkaline Phosphatase