title: Transient inhibition of the Hedgehog pathway in young mice causes permanent defects in bone structure.
abstract: The Hedgehog (Hh) pathway plays critical roles in normal development and in tumorigenesis. We generated Gli-luciferase transgenic mice to evaluate the Smo inhibitor, HhAntag, by whole animal functional imaging. HhAntag rapidly reduced systemic luciferase activity in 10- to 14-day-old mice following oral dosing. Although pathway activity was restored 2 days after drug removal, brief inhibition caused permanent defects in bone growth. HhAntag inhibited proliferation and promoted differentiation of chondrocytes, leading to dramatic expansion of the hypertrophic zone. After drug removal, osteoblasts invaded the cartilage plate, mineralization occurred, and there was premature fusion of the growth plate resulting in permanent disruption of bone epiphyses.
authors.affiliation: Department of Developmental Neurobiology, St. Jude Children's Research Hospital, 332 North Lauderdale Street, Memphis, TN 38105, USA.
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Kimura
authors.forename: Jessica M Y
authors.initials: JM
authors.lastname: Ng
authors.forename: Tom
authors.initials: T
authors.lastname: Curran
mesh_terms: D000284:Administration, Oral; D000375:Aging / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000633:toxicity*; D016723:Bone Remodeling / Q000187:drug effects; D001842:Bone and Bones / Q000187:drug effects* / Q000196:embryology / Q000378:metabolism / Q000473:pathology; D002113:Calcification, Physiologic / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D002528:Cerebellar Neoplasms / Q000188:drug therapy; D019902:Chondrocytes / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D006132:Growth Plate / Q000187:drug effects / Q000473:pathology; D053823:Hedgehog Proteins / Q000378:metabolism; D051741:Kruppel-Like Transcription Factors / Q000235:genetics / Q000378:metabolism; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008527:Medulloblastoma / Q000188:drug therapy; D051379:Mice; D008822:Mice, Transgenic; D008856:Microscopy, Fluorescence; D018715:Microscopy, Video; D010012:Osteogenesis / Q000187:drug effects; D043562:Receptors, G-Protein-Coupled / Q000037:antagonists & inhibitors* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D000072086:Smoothened Receptor; D013997:Time Factors; D000071676:Zinc Finger Protein GLI1
chemical_list: D000970:Antineoplastic Agents; C498520:Gli1 protein, mouse; D053823:Hedgehog Proteins; D051741:Kruppel-Like Transcription Factors; D043562:Receptors, G-Protein-Coupled; D011993:Recombinant Fusion Proteins; C491022:Smo protein, mouse; D000072086:Smoothened Receptor; D000071676:Zinc Finger Protein GLI1; D008156:Luciferases