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ludc webb

Isabel Goncalves

Professor

ludc webb

Oxidized LDL and lysophosphatidylcholine stimulate plasminogen activator inhibitor-1 expression in vascular smooth muscle cells

Author

  • Wolfgang Dichtl
  • Ann Stiko
  • Per Eriksson
  • Isabel Goncalves
  • Frederico Calara
  • Cristina Banfi
  • Mikko P Ares
  • Anders Hamsten
  • Jan Nilsson

Summary, in English

Plasminogen activator inhibitor-1 (PAI-1) functions as an important regulator of fibrinolysis by inhibiting both tissue-type and urokinase-type plasminogen activator. PAI-1 is produced by smooth muscle cells (SMCs) in atherosclerotic arteries, but the mechanisms responsible for induction of PAI-1 in SMCs are less well understood. In cultured human aortic SMCs, PAI-1 mRNA expression and protein secretion were increased after incubation with oxidized low-density lipoprotein (LDL) and the lipid peroxidation product lysophosphatidylcholine, whereas the effects of native LDL on PAI-1 production and release were more variable and did not reach statistical significance. The effect of LDL on arterial expression of PAI-1 in vivo was also studied in an animal model. Intravenous injection of human LDL in Sprague-Dawley rats resulted in accumulation of apolipoprotein B in the aorta within 12 hours as assessed by immunohistochemical testing. Epitopes specific for oxidized LDL began to develop in the aorta 12 hours after injection of LDL and peaked at 24 hours; this peak was accompanied by intense expression of PAI-1 immunoreactivity in the media. Also, increased aortic expression of PAI-1 mRNA after LDL injection was detected by using in situ hybridization. The transcription factor activator protein-1, which is known to bind to the promoter of the PAI-1 gene, was activated in the aortic wall 24 hours after LDL injection as assessed by electrophoretic mobility shift assay. Pretreatment of LDL with the antioxidant probucol decreased expression of oxidized LDL and PAI-1 immunoreactivity and activator protein-1 induction in the aorta but did not affect expression of apolipoprotein B immunoreactivity. These findings demonstrate that LDL oxidation enhances secretion of PAI-1 from cultured SMCs and that a similar mechanism may be involved in vascular expression of PAI-1.

Department/s

  • Cardiovascular Research - Translational Studies
  • Cardiovascular Research - Immunity and Atherosclerosis

Publishing year

1999

Language

English

Pages

32-3025

Publication/Series

Arteriosclerosis, Thrombosis, and Vascular Biology

Volume

19

Issue

12

Document type

Journal article

Publisher

Lippincott Williams & Wilkins

Topic

  • Medical and Health Sciences

Status

Published

Research group

  • Cardiovascular Research - Translational Studies
  • Cardiovascular Research - Immunity and Atherosclerosis