title: Loss of VHL in mesenchymal progenitors of the limb bud alters multiple steps of endochondral bone development.
abstract: Adaptation to low oxygen tension (hypoxia) is a critical event during development. The transcription factors Hypoxia Inducible Factor-1α (HIF-1α) and HIF-2α are essential mediators of the homeostatic responses that allow hypoxic cells to survive and differentiate. Von Hippel-Lindau protein (VHL) is the E3 ubiquitin ligase that targets HIFs to the proteasome for degradation in normoxia. We have previously demonstrated that the transcription factor HIF-1α is essential for survival and differentiation of growth plate chondrocytes, whereas HIF-2α is not necessary for fetal growth plate development. We have also shown that VHL is important for endochondral bone development, since loss of VHL in chondrocytes causes severe dwarfism. In this study, in order to expand our understanding of the role of VHL in chondrogenesis, we conditionally deleted VHL in mesenchymal progenitors of the limb bud, i.e. in cells not yet committed to the chondrocyte lineage. Deficiency of VHL in limb bud mesenchyme does not alter the timely differentiation of mesenchymal cells into chondrocytes. However, it causes structural collapse of the cartilaginous growth plate as a result of impaired proliferation, delayed terminal differentiation, and ectopic death of chondrocytes. This phenotype is associated to delayed replacement of cartilage by bone. Notably, loss of HIF-2α fully rescues the late formation of the bone marrow cavity in VHL mutant mice, though it does not affect any other detectable abnormality of the VHL mutant growth plates. Our findings demonstrate that VHL regulates bone morphogenesis as its loss considerably alters size, shape and overall development of the skeletal elements.
authors: Department of Orthopaedic Surgery, Medical School, University of Michigan, Ann Arbor, MI 48109, USA; Division of Endocrinology, Department of Medicine, School of Medicine, Indiana University, Indianapolis, IN 46202, USA; Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; Department of Orthopaedic and Traumatology, Milano-Bicocca University, 20900 Monza (MB), Italy.
authors: Laura
authors: L
authors: Mangiavini
authors: Department of Orthopaedic Surgery, Medical School, University of Michigan, Ann Arbor, MI 48109, USA; Division of Endocrinology, Department of Medicine, School of Medicine, Indiana University, Indianapolis, IN 46202, USA; Inserm, UMRS 791-LIOAD, Centre for Osteoarticular and Dental Tissue Engineering, Group STEP 'Skeletal Tissue Engineering and Physiopathology', 44042 Nantes, France; LUNAM, Nantes University, Faculty of Dental Surgery, Nantes, France.
authors: Christophe
authors: C
authors: Merceron
authors: Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
authors: Elisa
authors: E
authors: Araldi
authors: Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
authors: Richa
authors: R
authors: Khatri
authors: Division of Endocrinology, Department of Medicine, School of Medicine, Indiana University, Indianapolis, IN 46202, USA.
authors: Rita
authors: R
authors: Gerard-O'Riley
authors: Department of Orthopaedic Surgery, Medical School, University of Michigan, Ann Arbor, MI 48109, USA; Division of Endocrinology, Department of Medicine, School of Medicine, Indiana University, Indianapolis, IN 46202, USA; Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
authors: Tremika LeShan
authors: TL
authors: Wilson
authors: Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; Division of Radiation and Cancer Biology, Department of Radiation Oncology, Stanford University, Stanford, CA 94303-5152, USA.
authors: Erinn B
authors: EB
authors: Rankin
authors: Division of Radiation and Cancer Biology, Department of Radiation Oncology, Stanford University, Stanford, CA 94303-5152, USA.
authors: Amato J
authors: AJ
authors: Giaccia
authors: Department of Orthopaedic Surgery, Medical School, University of Michigan, Ann Arbor, MI 48109, USA; Division of Endocrinology, Department of Medicine, School of Medicine, Indiana University, Indianapolis, IN 46202, USA; Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; Division of Endocrinology, Department of Medicine, Medical School, University of Michigan, Ann Arbor, MI 48109, USA. Electronic address: eschipan@med.umich.edu.
authors: Ernestina
authors: E
authors: Schipani
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics; D002454:Cell Differentiation / Q000235:genetics; D015687:Cell Hypoxia; D049109:Cell Proliferation; D002478:Cells, Cultured; D020219:Chondrogenesis / Q000235:genetics / Q000502:physiology; D006132:Growth Plate / Q000196:embryology / Q000254:growth & development; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics; D018878:Limb Buds / Q000166:cytology; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D010012:Osteogenesis / Q000235:genetics*; D051794:Von Hippel-Lindau Tumor Suppressor Protein / Q000235:genetics / Q000502:physiology*; D000099162:Endothelial PAS Domain-Containing Protein 1
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D051794:Von Hippel-Lindau Tumor Suppressor Protein; D000099162:Endothelial PAS Domain-Containing Protein 1; C497443:Hif1a protein, mouse; C494469:VHL protein, mouse
keywords: Endochondral bone development; Hypoxia Inducible Factor; Limb bud mesenchyme; Von Hippel–Lindau