Document Detail


Synthesis and secretion of plasminogen activator inhibitor 1 by human endothelial cells in vitro. Effect of active site mutagenized tissue-type plasminogen activator.
MedLine Citation:
PMID:  1898737     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The effects of recombinant tissue-type plasminogen activator (rt-PA) and of an inactive mutant of rt-PA, obtained by mutagenesis of the active site Ser478 to Ala (rt-PA-Ala478), on the synthesis and secretion of plasminogen activator inhibitor-1 (PAI-1) by human umbilical vein endothelial cells (HUVEC) in culture were studied. Under base-line conditions, PAI-1 antigen secretion was 4.3 +/- 1.0 micrograms (mean +/- S.D., n = 8) per 10(6) cells in 24 h. This PAI-1 had a low specific activity (6,000 +/- 1,600 units/mg) and Mr of 50,000, which was not altered by addition of rt-PA. In HUVEC cultured with 2 micrograms/ml rt-PA-Ala478, PAI-1 antigen secretion was 2.1 +/- 0.8 micrograms (n = 5) per 10(6) cells in 24 h with a specific activity of 120,000 +/- 42,000 units/mg and Mr of 50,000. Addition of rt-PA to this conditioned medium resulted in generation of three main components: 16% migrated as an Mr 106,000 rt-PA.PAI-1 complex, 16% as an Mr 81,000 degraded rt-PA.PAI-1 complex and the remainder as an Mr 45,000 degradation product of PAI-1. HUVEC cultured with 2 micrograms/ml rt-PA secreted 3.9 +/- 0.6 micrograms (n = 8) PAI-1 antigen per 10(6) cells within 24 h, of which 20-50% occurred as intact or degraded complexes with t-PA (Mr 106,000 and 81,000) and the rest as an inactive Mr 45,000 degradation product of PAI-1. PAI-1 mRNA levels, determined by Northern blot analysis and expressed relative to beta-actin mRNA levels, were very similar for HUVEC cultured in the absence or the presence of rt-PA or rt-PA-Ala478. It is concluded that PAI-1 is secreted by HUVEC in culture in fully active form which spontaneously inactivates. PAI-1 can be stabilized by addition of rt-PA-Ala478 to the culture medium, resulting in a 20-fold increase in specific activity. Interaction of rt-PA with active PAI-1 produces both t-PA.PAI-1 complex and an inactive degradation product of PAI-1.
Authors:
K Bartha; P J Declerck; H Moreau; L Nelles; D Collen
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  266     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  1991 Jan 
Date Detail:
Created Date:  1991-02-12     Completed Date:  1991-02-12     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  792-7     Citation Subset:  IM    
Affiliation:
Center for Thrombosis and Vascular Research, University of Leuven, Belgium.
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MeSH Terms
Descriptor/Qualifier:
Antigens / genetics
Binding Sites
Blotting, Northern
Endothelium, Vascular / metabolism*
Humans
Mutation
Plasminogen Inactivators / metabolism*
RNA, Messenger / analysis
Recombinant Proteins / genetics
Tissue Plasminogen Activator / genetics*
Chemical
Reg. No./Substance:
0/Antigens; 0/Plasminogen Inactivators; 0/RNA, Messenger; 0/Recombinant Proteins; EC 3.4.21.68/Tissue Plasminogen Activator

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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