Oxidized low-density lipoprotein impairs the anti-coagulant function of tissue-factor-pathway inhibitor through oxidative modification by its high association and accelerated degradation in cultured human endothelial cells

We have examined whether oxidized low-density lipoprotein (ox-LDL) affects the function of tissue-factor-pathway inhibitor (TFPI), an anti-coagulant regulator in the extrinsic pathway of coagulation, in cultured human umbilical vein endothelial cells (HUVEC). Treatment of culture medium of HUVEC wit...

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Bibliographic Details
Published in:Biochemical journal 2000-12, Vol.352 Pt 2 (2), p.277-285
Main Authors: Horie, S, Hiraishi, S, Hirata, Y, Kazama, M, Matsuda, J
Format: Article
Language:English
Subjects:
Anticoagulants - metabolism
Cells, Cultured
Culture Media
Electrophoresis, Polyacrylamide Gel
Endothelium, Vascular - cytology
Endothelium, Vascular - metabolism
Humans
Lipoproteins - genetics
Lipoproteins - immunology
Lipoproteins - physiology
Lipoproteins, LDL - physiology
Oxidation-Reduction
RNA, Messenger - genetics
RNA, Messenger - metabolism
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Summary:We have examined whether oxidized low-density lipoprotein (ox-LDL) affects the function of tissue-factor-pathway inhibitor (TFPI), an anti-coagulant regulator in the extrinsic pathway of coagulation, in cultured human umbilical vein endothelial cells (HUVEC). Treatment of culture medium of HUVEC with ox-LDL, but not with native or acetylated LDLs, drastically decreased the reactivity of TFPI to its antibody specific for Kunitz domain 1 or one specific for the conformation between Kunitz 1 and 2 of TFPI, and caused a rapid, concentration-dependent decrease in the functional activity of TFPI to inhibit Factor X activation. When 5 ng of recombinant TFPI (rTFPI) was mixed with 10 microg of ox-LDL for 30 min, almost all of the rTFPI was detected in the ox-LDL fraction and no free rTFPI was observed on non-denaturing PAGE, in contrast with the virtual absence of rTFPI in the native LDL fraction. Ox-LDL decreased the antigen level of TFPI in the lysate of HUVEC in a time-dependent manner. It did not affect the mRNA level, but ox-LDL-dependent reduction of the TFPI antigen level in HUVEC was reversed by the simultaneous treatment of ox-LDL with bafilomycin A1, an inhibitor of the lysosomal proton pump. These results indicate that ox-LDL lessens the anti-coagulant function of TFPI through both oxidative modification and accelerated degradation of the molecule outside and inside HUVEC respectively.
ISSN:0264-6021
1470-8728
DOI:10.1042/0264-6021:3520277