title: Hyaluronate binding and degradation by cultured embryonic chick cardiac cushion and myocardial cells.
abstract: Cultured cells obtained from developing chick heart valvular and septal primordial tissues (cardiac cushions) and myocardium were tested for their capacity to bind, internalize, and degrade hyaluronate. A presumptive lysosomal hyaluronidase capable of hyaluronate degradation has been previously isolated and partially characterized from cultures enriched in either cushion tissue cells or myocardial cells (D. H. Bernanke and R. W. Orkin, 1984, Dev. Biol. 106, 351-359). In this study, both types of cultures were found to bind hyaluronate, but only the myocardial cultures could degrade the hyaluronate substrate. The lack of hyaluronate degradative capacity in the mesenchymal cushion tissue cells appears to result from their inability to internalize the macromolecule, thus failing to make it available to the lysosomal hyaluronidase. The data suggest that hyaluronate clearance from the extracellular matrix of the developing cushion is a complex process, involving more than simple extracellular degradation adjacent to the migrating mesenchymal cushion tissue cells. Instead, a sequence of events may be indicated which includes binding of hyaluronate to the cushion tissue cell surfaces and its transport by these cells across the cushion matrix toward the myocardium. The myocardium may be involved in the ultimate removal of hyaluronate from the cardiac jelly.
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D002352:Carrier Proteins / Q000378:metabolism*; D002478:Cells, Cultured; D002642:Chick Embryo; D006321:Heart / Q000196:embryology*; D018960:Hyaluronan Receptors; D006820:Hyaluronic Acid / Q000378:metabolism*; D007700:Kinetics; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D014316:Tritium
chemical_list: D002352:Carrier Proteins; D018960:Hyaluronan Receptors; D014316:Tritium; D006820:Hyaluronic Acid