Urokinase activity in the developing avian heart: a spatial and temporal analysis.
Early events in cardiac morphogenesis are characterized by cell migrations and extensive tissue remodeling. This study was undertaken to determine the levels of urokinase in specific regions of the avian heart during early stages of development. Urokinase has previously been shown to be involved in both cell migration and matrix turnover. Elevated urokinase activity and mRNA levels were associated with the onset of ventricular trabeculation and mesenchymal cell migration in the endocardial cushion tissues. Urokinase was localized by immunostaining to the endocardial and mesenchymal cells of the developing atrioventricular canal (AVC) and outflow tract (OFT) as well as with evaginating ventricular endocardium. No immunoreactivity was seen associated directly with the matrix, suggesting that the enzyme remained mostly cell associated, a finding which was confirmed in isolated endocardial cells. Results from this study suggest a role for urokinase in the tissue remodeling and cell migration that occurs during the early stages of cardiac morphogenesis.
McGuire
P G
PG
Department of Anatomy, University of New Mexico School of Medicine, Albuquerque 87131.
Orkin
R W
RW
D000818:Animals; D002478:Cells, Cultured; D002642:Chick Embryo; D003370:Coturnix; D006321:Heart / Q000196:embryology*; D009206:Myocardium / Q000166:cytology / Q000201:enzymology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014568:Urokinase-Type Plasminogen Activator / Q000032:analysis* / Q000235:genetics
D012333:RNA, Messenger; D014568:Urokinase-Type Plasminogen Activator