title: Stimulation of ectopic bone formation in response to BMP-2 by Rho kinase inhibitor: a pilot study.
abstract: The small GTPase Rho and Rho-associated protein kinase (Rho kinase, ROCK) signal participates in a variety of biological functions including vascular contraction, tumor invasion, and penile erection. Evidence also suggests Rho-ROCK is involved in signaling for mesenchymal cellular differentiation. However, whether it is involved in osteoblastic differentiation is unknown. We therefore asked whether Rho-ROCK signaling participates in recombinant human bone morphogenetic protein (rhBMP-2)-induced osteogenesis both in vitro and in vivo. Continuous delivery of a specific ROCK inhibitor (Y-27632) enhanced ectopic bone formation induced by rhBMP-2 impregnated into an atelocollagen carrier in mice without affecting systemic bone metabolism. Treatment with Y-27632 also enhanced the osteoblastic differentiation of cultured murine neonatal calvarial cells. These effects were associated with increased expression of BMP-4 gene. Expression of a dominant negative mutant of ROCK in ST2 cells promoted osteoblastic differentiation, while a constitutively active mutant of ROCK attenuated osteoblastic differentiation and the ROCK inhibitor reversed this phenotype. Thus, ROCK inhibits osteogenesis, and a ROCK inhibitor in combination with the local delivery of rhBMP/collagen composite may be clinically applicable for stimulating bone formation.
authors.affiliation: Department of Biology, Osaka Medical Center for Cancer and Cardiovascular Diseases, 1-3-2 Nakamichi, Higashinari-ku, Osaka 537-8511, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Yoshikawa
authors.forename: Kiyoko
authors.initials: K
authors.lastname: Yoshioka
authors.forename: Takanobu
authors.initials: T
authors.lastname: Nakase
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Itoh
mesh_terms: D000577:Amides / Q000008:administration & dosage*; D000818:Animals; D000831:Animals, Newborn; D055396:Bone Morphogenetic Protein 2 / Q000008:administration & dosage*; D055415:Bone Morphogenetic Protein 4 / Q000235:genetics; D002454:Cell Differentiation / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D003094:Collagen; D004305:Dose-Response Relationship, Drug; D004337:Drug Carriers; D006801:Humans; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009154:Mutation; D009999:Ossification, Heterotopic / Q000139:chemically induced* / Q000201:enzymology / Q000503:physiopathology; D010006:Osteoblasts / Q000187:drug effects* / Q000201:enzymology; D010012:Osteogenesis / Q000187:drug effects*; D010865:Pilot Projects; D047428:Protein Kinase Inhibitors / Q000008:administration & dosage*; D011725:Pyridines / Q000008:administration & dosage*; D012333:RNA, Messenger / Q000378:metabolism; D011994:Recombinant Proteins / Q000008:administration & dosage; D012886:Skull / Q000187:drug effects / Q000201:enzymology; D017154:Stromal Cells / Q000187:drug effects / Q000201:enzymology; D014162:Transfection; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism
chemical_list: D000577:Amides; C525718:BMP2 protein, human; C525810:Bmp4 protein, mouse; D055396:Bone Morphogenetic Protein 2; D055415:Bone Morphogenetic Protein 4; D004337:Drug Carriers; D047428:Protein Kinase Inhibitors; D011725:Pyridines; D012333:RNA, Messenger; D011994:Recombinant Proteins; C059821:atelocollagen; C108830:Y 27632; D003094:Collagen; D054460:rho-Associated Kinases