17beta-Estradiol induces protein S-nitrosylation in the endothelium.
OBJECTIVE
Estrogen induces nitric oxide (NO) in the endothelium and appears to protect against inflammation and atherosclerosis. NO can induce post-translational protein modifications such as cysteine S-nitrosylation in the cellular proteins which may exert anti-inflammatory effects. However, whether estrogen can induce protein S-nitrosylation in the endothelium is not known. Given this background, we investigated the role of 17beta-estradiol (E2beta), the major form of estrogen in the body, on endothelial protein S-nitrosylation.


RESULTS
Experiments were performed in human umbilical vein endothelial cells (HUVECs). S-nitrosylation was detected by immunostaining for nitrosocysteine and further confirmed by biotin switch method. Ovariectomized 12-month-old Sprague-Dawley rats with/without estradiol supplementation were used for in vivo validation of findings. We found that physiologically relevant doses of E2beta increased protein S-nitrosylation in HUVECs through estrogen receptor-alpha (ERalpha) and endothelial nitric oxide synthase (eNOS). Interestingly, specific agonists for both ERalpha and ERbeta increased eNOS protein expression, while only the former could activate eNOS through phosphorylation. S-nitrosylation by E2beta prevented angiotensin II-induced upregulation of intercellular cell adhesion molecule-1, suggesting a potential anti-inflammatory mechanism. Finally, we showed that exogenous E2beta could increase endothelial S-nitrosylation in vivo in a rat model.


CONCLUSIONS
Our results demonstrate for the first time that E2beta increases protein S-nitrosylation in the vascular endothelium, which might be a novel pathway to mediate the protective effects on the vasculature.
Chakrabarti
Subhadeep
S
Department of Obstetrics and Gynecology, Women and Children's Health Research Institute (WCHRI), Cardiovascular Research Centre and Mazankowski Alberta Heart Institute, University of Alberta, 232 HMRC, Edmonton, AB, Canada.
Lekontseva
Olga
O
Peters
Amber
A
Davidge
Sandra T
ST
D000804:Angiotensin II / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D001011:Aorta / Q000166:cytology / Q000378:metabolism; D002478:Cells, Cultured; D003545:Cysteine / Q000378:metabolism; D004195:Disease Models, Animal; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D004958:Estradiol / Q000494:pharmacology*; D047628:Estrogen Receptor alpha / Q000819:agonists / Q000378:metabolism; D047629:Estrogen Receptor beta / Q000819:agonists / Q000378:metabolism; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D006801:Humans; D009569:Nitric Oxide / Q000378:metabolism; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014471:Umbilical Veins / Q000166:cytology / Q000378:metabolism; D014662:Vasoconstrictor Agents / Q000378:metabolism / Q000494:pharmacology
D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D004967:Estrogens; D014662:Vasoconstrictor Agents; D000804:Angiotensin II; D009569:Nitric Oxide; D004958:Estradiol; C496320:NOS1 protein, human; C496319:NOS2 protein, human; C496314:NOS3 protein, human; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D003545:Cysteine; D009584:Nitrogen