An essential role for the interaction between hyaluronan and hyaluronan binding proteins during joint development.
We studied the expression of hyaluronan binding proteins (HABPs) during the development of embryonic chick joints, using immunocytochemistry and biotinylated HA. The expression of actin capping proteins and of actin itself was also studied because the cytoskeleton is important in controlling HA-HABP interactions. Three cell surface HABPs were localized in the epiphyseal cartilage, articular fibrocartilage, and interzone that comprise the developing joint. Of these three HABPs, CD44 was associated with the articular fibrocartilages and interzone, whereas RHAMM and the IVd4 epitope were associated with all three tissues. Biotinylated HA was localized to interzone and articular fibrocartilages before cavity formation and within epiphyseal chondrocytes post cavitation. Actin filament bundles were observed at the developing joint line, as was the expression of the actin capping protein moesin. Manipulation of joint cavity development, using oligosaccharides of HA, disrupted joint formation and was associated with decreases in CD44 and actin filament expression as well as decreased hyaluronan synthetic capability. These results suggest that HA is actively bound by CD44 at the developing joint line and that HA-HABP interactions play a major role in the initial separation events occurring during joint formation.
Dowthwaite
G P
GP
Department of Veterinary Basic Sciences, The Royal Veterinary College, University of London, London, United Kingdom.
Edwards
J C
JC
Pitsillides
A A
AA
D000199:Actins / Q000378:metabolism; D000818:Animals; D000911:Antibodies, Monoclonal; D001798:Blood Proteins / Q000378:metabolism; D002356:Cartilage / Q000166:cytology / Q000378:metabolism; D002455:Cell Division; D002642:Chick Embryo; D003598:Cytoskeletal Proteins; D003692:Delayed-Action Preparations; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D006614:Hindlimb / Q000254:growth & development; D018960:Hyaluronan Receptors / Q000378:metabolism*; D006820:Hyaluronic Acid / Q000008:administration & dosage / Q000378:metabolism*; D007124:Immunoenzyme Techniques; D007596:Joints / Q000196:embryology* / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D008840:Microfilament Proteins; D009844:Oligosaccharides / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D011485:Protein Binding; D011506:Proteins / Q000378:metabolism; D013499:Surface Properties; D014533:Uridine Diphosphate Glucose Dehydrogenase / Q000378:metabolism; D000099149:Ezrin
D000199:Actins; D000911:Antibodies, Monoclonal; D001798:Blood Proteins; D003598:Cytoskeletal Proteins; D003692:Delayed-Action Preparations; D016326:Extracellular Matrix Proteins; D018960:Hyaluronan Receptors; D006820:Hyaluronic Acid; D008565:Membrane Proteins; D008840:Microfilament Proteins; D009844:Oligosaccharides; D010750:Phosphoproteins; D011506:Proteins; D014533:Uridine Diphosphate Glucose Dehydrogenase; D000099149:Ezrin; C098946:hyaluronan-mediated motility receptor; C071058:moesin; C071776:radixin