Suppression by 17beta-estradiol of monocyte adhesion to vascular endothelial cells is mediated by estrogen receptors.
Several observational studies have shown that estrogen replacement therapy decreases cardiovascular mortality and morbidity in postmenopausal women. However, The Women's Health Initiative (WHI) study has found that women receiving estrogen plus progestin had a significantly higher risk of breast cancer, coronary heart disease, stroke, and pulmonary embolus. In the present study, we examined whether estrogen prevents mechanisms that relate to plaque formation by inhibiting monocyte adhesion to endothelial cells. ECV304 cells, an endothelial cell line that normally expresses minimal estrogen receptor (ER)alpha, were transfected with an ERalpha expression plasmid. Treatment with tumor necrosis factor (TNF)-alpha increased expression of vascular cell adhesion molecule (VCAM)-1 mRNA, activation of nuclear factor-kappaB (NF-kappaB), and U937 cell adhesion in ECV304 cells. These effects of TNF-alpha were not significantly inhibited by pretreatment of native ECV304 cells with 17beta-estradiol (E(2)). In ECV304 cells overexpressing ERalpha, E(2) significantly inhibited the effects of TNF-alpha on NF-kappaB activation, VCAM-1 expression, and U937 cell adhesion. These findings suggest E(2) suppresses inflammatory cell adhesion to vascular endothelial cells that possess functional estrogen receptors. The mechanism of suppression may involve inhibition of NF-kappaB-mediated up-regulation of VCAM-1 expression induced by atherogenic stimuli. E(2) may prevent plaque formation, as first stage of atheroscrelosis through inhibiting adhesion monocytes to endothelial cell. Actions of estrogen replacement therapy can be assessed in terms of densities of functional ERalpha.
Mori
Michiko
M
Department of Obstetrics and Gynecology, Tokyo Women's Medical University School of Medicine, 8-1, Kawada-cho, Shinjuku, Tokyo, 162-8666, Japan. ciw75830@rio.odn.ne.jp
Tsukahara
Fujiko
F
Yoshioka
Toshimasa
T
Irie
Kaoru
K
Ohta
Hiroaki
H
D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D004958:Estradiol / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D009000:Monocytes / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D016328:NF-kappa B / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011959:Receptors, Estradiol / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D020298:U937 Cells / Q000187:drug effects / Q000502:physiology; D015854:Up-Regulation; D019010:Vascular Cell Adhesion Molecule-1 / Q000235:genetics / Q000378:metabolism
D016328:NF-kappa B; D012333:RNA, Messenger; D011959:Receptors, Estradiol; D014409:Tumor Necrosis Factor-alpha; D019010:Vascular Cell Adhesion Molecule-1; D004958:Estradiol