Regulation of in vitro glia-induced microvessel morphogenesis by urokinase.
Plasminogen activators (PAs) regulate a variety of processes involved in tissue morphogenesis and differentiation. We used a coculture system in which microvascular endothelial cells are induced by glial cells to form capillary-like structures in order to examine the role of urokinase-type PA (uPA) during microvessel morphogenesis within the central nervous system (CNS). Endothelia-derived uPA activity decreased sevenfold within glial-endothelial cocultures when capillary-like structures were formed. Incubation of cocultures with concentrations of phorbol 12-myristate 13-acetate (0.1 and 1.0 nM) that induced endothelial uPA activity (45-210%) inhibited endothelial differentiation (25-70%). Furthermore, incubation of cocultures with proteolytically active low molecular weight uPA (5-500 IU/ml) inhibited endothelial differentiation (37-75%), whereas the amino terminal cell-binding fragment of uPA had minimal effect. Inhibition of plasminogen activation in cocultures with the serine protease/plasmin inhibitors aprotinin and soybean trypsin inhibitor increased glia-induced capillary-like structure formation (96-98%). These findings establish a paracrine/autocrine function for urokinase and its inhibitors in regulating endothelial responses to perivascular glia and provide insight into mechanisms of microvascular reactions to CNS pathology.
Laterra
J
J
Department of Neurology, Kennedy Krieger Research Institute, Johns Hopkins Medical Institutions, Baltimore, Maryland 21205.
Indurti
R R
RR
Goldstein
G W
GW
D000818:Animals; D002196:Capillaries / Q000254:growth & development; D002417:Cattle; D004730:Endothelium, Vascular / Q000166:cytology* / Q000187:drug effects* / Q000201:enzymology; D004790:Enzyme Induction; D005341:Fibrinolysin / Q000037:antagonists & inhibitors; D009457:Neuroglia / Q000502:physiology*; D010446:Peptide Fragments / Q000494:pharmacology; D051381:Rats; D012171:Retinal Vessels / Q000166:cytology / Q000254:growth & development*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism / Q000494:pharmacology*
D010446:Peptide Fragments; D005341:Fibrinolysin; D014568:Urokinase-Type Plasminogen Activator; D013755:Tetradecanoylphorbol Acetate