Regulation of plasminogen activation by TGF-[beta] in cultured human retinal endothelial cells

BACKGROUND/AIMS Regulation of plasmin mediated extracellular matrix degradation by vascular endothelial cells is important in the development of angiogenesis. The aim was to determine whether transforming growth factor β (TGF-β) affected the regulation of components of the plasminogen system by huma...

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Bibliographic Details
Published in:British journal of ophthalmology 2000-04, Vol.84 (4), p.417
Main Authors: Wileman, Samantha M, Booth, Nuala A, Moore, Norma, Redmill, Brian, rester, John V, Knott, Rachel M
Format: Article
Language:English
Subjects:
Angiogenesis
Cell culture
Cell growth
Diabetes
Diabetic retinopathy
Endothelium
Extracellular matrix
Growth factors
Phosphatase
Retina
Studies
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Summary:BACKGROUND/AIMS Regulation of plasmin mediated extracellular matrix degradation by vascular endothelial cells is important in the development of angiogenesis. The aim was to determine whether transforming growth factor β (TGF-β) affected the regulation of components of the plasminogen system by human retinal endothelial cells, in order to define more clearly the role of TGF-β in retinal angiogenesis in the context of diabetes mellitus. METHODS Human retinal endothelial cells (HREC) were isolated from donor eyes and used between passages 4-8. The cells were cultured in medium supplemented with 2, 5, 15, or 25 mM glucose, plus or minus TGF-β (1 ng/ml). The concentrations of tissue plasminogen activator (t-PA), urokinase plasminogen activator (u-PA), and plasminogen activator inhibitor type 1 (PAI-1) in cell conditioned medium were determined by ELISA and the level of PAI-1 mRNA was determined using northern hybridisation. Cell associated plasminogen activity was determined using a clot lysis assay and a chromogenic assay. RESULTS Under basal conditions (5 mM glucose), HREC produced PAI-1, t-PA, and trace amounts of u-PA. Cell surface plasminogen activation observed by lysis of fibrin or by cleavage of chromogenic substrate, was mediated by t-PA. Glucose at varying concentrations (2-25 mM) had no significant effect on t-PA mediated clot lysis. In contrast, treatment with TGF-β resulted in increased synthesis of PAI-1 protein and mRNA. The increased expression of the P AI -1 mRNAs by TGF-β did not occur uniformly, the 2.3 kb mRNA transcript was preferentially increased in comparison with the 3.2 kb mRNA (p
ISSN:0007-1161
1468-2079
DOI:10.1136/bjo.84.4.417