title: Platelet-derived growth factor A modulates limb chondrogenesis both in vivo and in vitro.
abstract: Cartilage formation in the chick limb follows rapid proliferation, condensation and differentiation of limb mesenchyme. The control of these early events is poorly understood. Platelet-derived growth factor receptor alpha (PDGFR-alpha) is present throughout the mesenchyme of early chick limb buds, while its ligand, PDGF-A, is expressed in the surrounding epithelium. PDGFR-alpha is down-regulated in areas that will not give rise to cartilage and is then lost from cartilage forming areas after they begin to differentiate. PDGF-A increases chondrogenesis in micromass cultures of stage-20-24 limb buds, but not stage 25, where it inhibits chondrogenesis. Ectopic PDGF-A in the chick wing can lead to either a localized increase in cartilage formation, or an inhibition. Inhibition of PDGF signalling in the chick limb results in the loss of cartilage. These data demonstrate that PDGF-A functions to promote chondrogenesis at early stages of limb development and suggest that it inhibits chondrogenesis at later stages.
authors.affiliation: MRC Laboratory for Molecular Cell Biology, University College London, UK. p.ataliotis@ucl.ac.uk
authors.forename: P
authors.initials: P
authors.lastname: Ataliotis
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics; D002356:Cartilage / Q000196:embryology*; D002642:Chick Embryo; D020219:Chondrogenesis / Q000235:genetics*; D004247:DNA / Q000096:biosynthesis; D005121:Extremities / Q000196:embryology*; D018507:Gene Expression Regulation, Developmental; D018878:Limb Buds / Q000502:physiology; D009924:Organ Culture Techniques; D010982:Platelet-Derived Growth Factor / Q000235:genetics* / Q000378:metabolism; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000235:genetics; D015398:Signal Transduction
chemical_list: D010982:Platelet-Derived Growth Factor; C075278:platelet-derived growth factor A; D004247:DNA; D020796:Receptor, Platelet-Derived Growth Factor alpha