Effects of 17β-Estradiol on the Plasminogen Activator System in Vascular Smooth Muscle Cells Treated with Lysophophatidylcholine
- Author:
Byung-Koo YOON
1
;
Young-Hee KANG
;
Won-Jong OH
;
Dong-Yun LEE
;
Duk-Kyung KIM
;
Bruce KESSEL
;
Chi-Dug KANG
Author Information
- Publication Type:ORIGINAL ARTICLE
- From:Journal of Menopausal Medicine 2020;26(1):9-17
- CountryRepublic of Korea
- Language:0
-
Abstract:
Objectives:When administered soon after menopause, hormone therapy can prevent coronary heart diseases in women. To explore the mechanism underlying the cardioprotective actions of estrogen, we investigated the effects of 17β-estradiol (17β-E2) on the plasminogen activator system using cultured vascular smooth muscle cells (VSMCs).
Methods:VSMCs were isolated from rat aortas. Protein expression of plasminogen activator inhibitor type 1 (PAI-1) and tissue-type plasminogen activator (t-PA) were evaluated using Western blotting and enzyme-linked immunosorbent assay, respectively. The enzyme activity of PAI-1 in a conditioned medium was assessed via reverse fibrin overlay zymography and that of t-PA was assessed via fibrin overlay zymography. Gene expression was quantified using real-time reverse transcription-polymerase chain reaction.
Results:Following pre-treatment for 24 hours, 17β-E2 suppressed both protein expression and enzyme activity of PAI-1 stimulated by lysophosphatidylcholine (lysoPC) in a significant and dose-dependent manner at a near physiological concentration. Moreover, 17β-E2 (10−7 M) inhibited PAI-1 gene expression, and ICI 182,780—a specific estrogen receptor antagonist—blocked the effects of 17β-E2 on the PAI-1 protein. 17β-E2 did not affect t-PA secretion but significantly enhanced free t-PA activity through reduced binding to PAI-1. Furthermore, 17β-E2 suppressed intracellular reactive oxygen species production and nuclear factor-κB-mediated transcription.
Conclusions:In VSMCs stimulated with lysoPC, 17β-E2 reduced PAI-1 expression through a non-receptor-mediated mechanism via antioxidant activity as well as a receptor-mediated mechanism; however, it did not alter t-PA secretion. Of note, 17β-E2 suppressed PAI- 1 activity and concurrently enhanced t-PA activity, suggesting a beneficial influence on fibrinolysis.
