title: Effects of 17 β-estradiol on lipopolysacharride-induced intracellular adhesion molecule-1 mRNA expression and Ca²+ homeostasis alteration in human endothelial cells.
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 E(2) significantly inhibited LPS-induced ICAM-1 mRNA expression. [Ca²+](i) was monitored in Fura-2AM-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.
authors.affiliation: Department of Physiology and Pharmacology, Thomas J. Long School of Pharmacy and Health Sciences, University of the Pacific, Stockton, CA, USA.
authors.forename: Der
authors.initials: D
authors.lastname: Thor
authors.forename: Rui
authors.initials: R
authors.lastname: Zhang
authors.forename: Leigh
authors.initials: L
authors.lastname: Anderson
authors.forename: Diptiman D
authors.initials: DD
authors.lastname: Bose
authors.forename: Gregory P
authors.initials: GP
authors.lastname: Dubé
authors.forename: Roshanak
authors.initials: R
authors.lastname: Rahimian
mesh_terms: D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology*; D004965:Estrogen Antagonists / Q000494:pharmacology; D004967:Estrogens / Q000494:pharmacology*; D000077267:Fulvestrant; D006706:Homeostasis; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis* / Q000235:genetics; D008070:Lipopolysaccharides / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis*
chemical_list: D004965:Estrogen Antagonists; D004967:Estrogens; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D018799:Intercellular Adhesion Molecule-1; D000077267:Fulvestrant; D004958:Estradiol; D002118:Calcium