Mechanisms of GDF-5 action during skeletal development

Development. 1999 Mar;126(6):1305-15. doi: 10.1242/dev.126.6.1305.

Abstract

Mutations in GDF-5, a member of the TGF-beta superfamily, result in the autosomal recessive syndromes brachypod (bp) in mice and Hunter-Thompson and Grebe-type chondrodysplasias in humans. These syndromes are all characterised by the shortening of the appendicular skeleton and loss or abnormal development of some joints. To investigate how GDF-5 controls skeletogenesis, we overexpressed GDF-5 during chick limb development using the retrovirus, RCASBP. This resulted in up to a 37.5% increase in length of the skeletal elements, which was predominantly due to an increase in the number of chondrocytes. By injecting virus at different stages of development, we show that GDF-5 can increase both the size of the early cartilage condensation and the later developing skeletal element. Using in vitro micromass cultures as a model system to study the early steps of chondrogenesis, we show that GDF-5 increases chondrogenesis in a dose-dependent manner. We did not detect changes in proliferation. However, cell suspension cultures showed that GDF-5 might act at these stages by increasing cell adhesion, a critical determinant of early chondrogenesis. In contrast, pulse labelling experiments of GDF-5-infected limbs showed that at later stages of skeletal development GDF-5 can increase proliferation of chondrocytes. Thus, here we show two mechanisms of how GDF-5 may control different stages of skeletogenesis. Finally, our data show that levels of GDF-5 expression/activity are important in controlling the size of skeletal elements and provides a possible explanation for the variation in the severity of skeletal defects resulting from mutations in GDF-5.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Bone Morphogenetic Proteins*
  • Bone and Bones / embryology*
  • Cartilage / embryology*
  • Cell Aggregation / drug effects
  • Cell Division / drug effects
  • Chick Embryo
  • Chondrogenesis / drug effects
  • Cloning, Molecular
  • DNA / analysis
  • Extremities / embryology*
  • Glycosaminoglycans / analysis
  • Growth Differentiation Factor 5
  • Growth Substances / genetics
  • Growth Substances / metabolism*
  • Growth Substances / pharmacology
  • Humerus / chemistry
  • Limb Buds / embryology
  • Molecular Sequence Data
  • Recombinant Proteins / metabolism
  • Sequence Homology, Amino Acid

Substances

  • Bone Morphogenetic Proteins
  • GDF5 protein, human
  • Gdf5 protein, mouse
  • Glycosaminoglycans
  • Growth Differentiation Factor 5
  • Growth Substances
  • Recombinant Proteins
  • A73025
  • DNA

Associated data

  • GENBANK/AF123389