Effects of 17 β-estradiol on lipopolysacharride-induced intracellular adhesion molecule-1 mRNA expression and Ca2+ homeostasis alteration in human endothelial cells

• Published in: Vascular pharmacology 2010-11, Vol.53 (5), p.230-238
• Main Authors: Thor, Der, Zhang, Rui, Anderson, Leigh, Bose, Diptiman D, Dubé, Gregory P, Rahimian, Roshanak
• Format: Article
• Language: English
• Subjects: Calcium - metabolism; Cardiovascular; Cell Line; Endothelial Cells - drug effects; Endothelial Cells - metabolism; Estradiol - analogs & derivatives; Estradiol - pharmacology; Estrogen Antagonists - pharmacology; Estrogens - pharmacology; Homeostasis; Humans; Intercellular Adhesion Molecule-1 - biosynthesis; Intercellular Adhesion Molecule-1 - genetics; Lipopolysaccharides - pharmacology; RNA, Messenger - biosynthesis
• ISSN: 1537-1891; 1879-3649
• DOI: 10.1016/j.vph.2010.09.001

Abstract Recent evidence showed that 17 β-estradiol (E2 ) decreased cytokine-induced expression of cell adhesion molecules (CAM). Changes in intracellular Ca2+ concentration ([Ca2+ ]i ) has been shown to be associated with CAM expression in endothelial cells. Here, the effects of E2 (1 μM, 24 h) on the expression of intracellular adhesion molecule-1 (ICAM-1) and [Ca2+ ]i were investigated in a lipopolysaccharide (LPS) (100 ng/mL, 18 h)-stimulated human endothelial cell line, EA.hy926, using real-time PCR and spectrofluorometry, respectively. PCR analysis revealed a significant increase in ICAM-1 expression in calcium ionophore A23187 (1 nM)- or LPS-stimulated cells. Pretreatment of cells with E2 significantly inhibited LPS-induced ICAM-1 mRNA expression. [Ca2+ ]i was monitored in Fura-2 AM-loaded cells in the presence and absence of extracellular Ca2+ with thapsigargin (TG, 1 μM), a sarco/endoplasmic reticulum ATPase inhibitor or ATP (100 μM). The extent of TG- or ATP-induced [Ca2+ ]i increase was significantly higher in LPS-stimulated cells than in control cells. Pre-treatment of LPS-stimulated cells with E2 limited the Ca2+ response to the same level as in control cells. Furthermore, ICI 182,780, an estrogen receptor antagonist, attenuated the inhibitory actions of E2 on ICAM-1 mRNA expression and Ca2+ responses, suggesting that estrogen receptors mediate, at least in part, the effects of estrogen. These data suggest a potential underlying mechanism for the protective effect of E2 against atherosclerosis.