雌激素及脱氢表雄酮对血管内皮细胞内质网应激调控的机制探讨

Cardiovascular disease is the leading cause of morbidity and.mortality in postmenopausal women. Estrogen may have protective effects in the cardiovascular system, as evidenced by the decreased incidence of cardiovascular disease (CVD) in premenopausal compared with postmenopausal women.There is evidence that estrogen therapy may be cardioprotective if started around the time of menopause and continued long term (often referred to as the 'window of opportunity'concept)..The mechanism of hypertension cuased by endogenous estrogen de?cient is complex and is affected by many factors such as postmenopausal vascular aging, atherosclerosis, obesity, insulin resistance and abnormal lipid metabolism.Dehydroepiandrosterone (DHEA) and its sulphate DHEAS are the most abundant steroids the human body, however their mechanism of action and physogical implications are not well understood.The endoplasmic reticulum(ER) is a vast membranous network responsible for the synthesis,maturation, and traf?cking of a wide range of proteins.It is also a critical site for Ca2+homeostasis. As a central regulator of protein folding, quality control, traf?cking, and targeting,the ability of the ER to adapt its capacity to manage synthetic,metabolic, and other adverse conditions is of paramount importance for the cell. Under conditions that challenge ER function,particularly an increase in newly synthesized, unfolded proteins in the ER lumen, this organelle elicits an elaborate adaptive response known as the UPR . The endoplasmic reticulum stress in endothelial cells involved in disease and development of vascular injury,Excessive endoplasmic reticulum stress causes vascular endothelial cell dysfunction, apoptosis, and promotes the occurrence of atherosclerosis development. The apoptosis pathway mediated by endoplasmic reticulum is involved in coronary artery endothelial cell injury.The exact mechanism of blood pressure regulation by estrogen is complex and not clarified. And the effects of estrogen and DHEA on internal endoplasmic reticulum stress is not clear.Our study will explore whether the inhibition by estrogen and DHEA on endoplasmic reticulum stress response is the cellular molecular mechanism of hypertensive cardiovascular remodeling antagonism. Also, by establishing the stress response model of cardiac muscle cell endoplasmic reticulum, our study will explore the signal transduction pathway of ER stress inhibition by estrogen and DHEA. The results of our study will guide us modify the regiment of hormone replacement therapy.The administration of individualized HRT (including androgenic preparations when approriate) may improve both sexuality and overall quality of life.

心血管疾病是绝经后女性死亡的首位原因，雌激素对绝经前妇女的心血管系统有保护作用，而且在绝经后早期（时间窗）开始激素补充治疗，能降低心血管疾病的发生，内源性雌激素缺乏对高血压发生的机制复杂并受多种因素影响，血管内皮细胞内质网应激参与血管损伤相关疾病发生及发展，过度内质网应激导致血管内皮细胞功能障碍，凋亡，促进动脉粥样硬化的发生、发展，而且内质网介导的凋亡相关途径参与冠状动脉内皮细胞损伤。雌激素调控血压的确切机制及对内质网应激的作用尚不清楚，脱氢表雄酮目前广泛用于营养补充，但对绝经后妇女心血管作用不明，本研究通过建立高血压心血管重塑模型，探讨雌激素及脱氢表雄酮抑制内质网应激反应是否为拮抗高血压心血管重塑的细胞分子机制，并通过心肌细胞内质网应激模型建立，研究雌激素和脱氢表雄酮抑制内质网应激的信号传导机制，探讨性激素对心血管的保护机制，指导绝经后妇女合理的应用激素补充治疗，使她们从中获得最大利益。

心血管疾病是绝经后女性死亡的首位原因，雌激素对绝经前妇女的心血管系统有保护作用，血管内皮细胞内质网应激（ERS）参与血管损伤相关疾病发生及发展，过度内质网应激导致血管内皮细胞功能障碍，凋亡，本研究探讨雌激素及脱氢表雄酮抑制内质网应激反应是否为拮抗高血压心血管重塑的细胞分子机制，并通过脐静脉内皮细胞内质网应激模型建立，研究雌激素（E2）和脱氢表雄酮（DHEA）抑制内质网应激的信号传导机制，探讨性激素对心血管的保护机制，指导绝经后妇女合理的应用激素补充治疗。本研究先分别用10μmol/L的衣霉素（Tunicamycin，TM）或2mmol/L的二硫苏糖醇（Dithiothreitol，DTT）建立内质网（ERS）的细胞模型，进而探索E2和DHEA对ERS的作用。模型建立后首先检测ERS的三条主要的信号通路蛋白的变化，上调最显著的为ERS最主要的信号通路，用Western blot检测ERS凋亡蛋白C/EBP-同源蛋白（C/EBP-homologous protein, CHOP）的表达 ，Hochest染色检测细胞凋亡率，探索E2对ERS凋亡的作用。然后添加E2受体拮抗剂ICI182,780（ERα、ERβ拮抗剂及GPER激动剂）和G15（GPER拮抗剂）后检测ERS最主要通路蛋白表达量的变化,探索雌激素受体在其抑制ERS中的作用。最后添加E2 受体后信号通路阻断剂，检测雌激素抑制ERS的过程中活化其受体后激活的最主要的受体后信号通路。通过上述实验本研究发现了雌激素防止动脉粥样硬化保护心血管系统的新途径,即通过抑制PERK信号通路引起的ERS凋亡，保护血管内皮细胞,其抑制ERS的机制主要为活化的雌激素受体激活PI3K/Akt通路。在探讨DHEA通过抑制内质网应激反应拮抗高血压心血管重塑的实验方面，我们的研究在HUVEC内质网应激模型上发现DHEA可以抑制HUVEC ERS凋亡，ERK1/2和JNK通路阻断剂可阻断DHEA抑制内质网应激的作用。我们的研究首次发现DHEA可以通过激活ERK1/2和JNK通路抑制ERS凋亡，揭示了DHEA抑制HUVEC ERS凋亡的新机制，为预防动脉粥样硬化提供了新的靶点。