Ethanol downregulates transcription of the PAI-1 gene in cultured human endothelial cells.
Human endothelial cells are a major site of synthesis for plasminogen activator inhibitor type-1. Elevated plasminogen activator inhibitor type-1 levels in young survivors of myocardial infarction [1] suggest that plasminogen activator inhibitor type-1 may have an important pathologic role in the development of coronary artery disease. Epidemiological studies indicate that moderate alcohol consumption (1-2 drinks/day) reduces the risk for cardiovascular mortality. This cardioprotective benefit has been attributed in part to an increase in fibrinolysis, which decreases fibrin-based thrombosis. The studies described herein were performed to determine whether moderate levels of ethanol affect plasminogen activator inhibitor type-1 gene expression. Cultured human endothelial cells were exposed to 0.1% v/v ethanol for 1 hour. Following incubation in the absence of ethanol plasminogen activator inhibitor type-1, mRNA levels were decreased in a time- and dose-dependent manner, reaching a maximum decrease of 3- to 4-fold at 2 to 4 hours following ethanol challenge. This decline in mRNA occurs at the transcription level; therefore, nuclear transcription run-on assays were performed. A 2.5- to 5-fold decrease in the rate of plasminogen activator inhibitor type-1 gene transcription was measured at 2 and 4 hours following ethanol challenge. Next, a 3.4- and a 1.1-kb fragment from the plasminogen activator inhibitor type-1 promoter region were linked to a luciferase reporter gene, and these constructs were transfected into human endothelial cells. Treatment of these transiently transfected human endothelial cells with ethanol showed a 2- to 3.5-fold decrease in promoter activity, respectively. These results indicate that low doses of ethanol downregulate transcription of the plasminogen activator inhibitor type-1 gene in cultured human endothelial cells. However, the mechanism(s) for this transcriptional decrease is currently unknown.
Grenett
H E
HE
Department of Medicine, University of Alabama at Birmingham, 35294, USA. hgrenett@cardio.dom.uab.edu
Aikens
M L
ML
Tabengwa
E M
EM
Davis
G C
GC
Booyse
F M
FM
D002478:Cells, Cultured; D015536:Down-Regulation / Q000187:drug effects*; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000502:physiology; D000431:Ethanol / Q000494:pharmacology*; D006801:Humans; D017395:Plasminogen Activator Inhibitor 1 / Q000096:biosynthesis / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000187:drug effects / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis / Q000187:drug effects; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection; D014471:Umbilical Veins
D017395:Plasminogen Activator Inhibitor 1; D012333:RNA, Messenger; D000431:Ethanol