Investigation and clinical application of estrogen receptor α and β prevent vascular disease

我们的研究目的是阐明雌激素的动脉粥样硬化保护作用，特别是雌激素受体（ER）亚型的作用，并应用雌激素受体预防动脉粥样硬化的新治疗方法。我们在三年中取得了六项成果，如下所述。(1)探讨糖尿病对动脉粥样硬化的影响与ER的关系。我们发现，在高糖状态下，培养的血管平滑肌细胞中Erα的表达降低，这是通过蛋白激酶c的激活介导的。(2)我们成功构建了过表达Erα和Erβ均具有显性负转录活性的ER突变体转基因小鼠。在这只小鼠的股动脉周围放置聚乙烯袖套形成新生内膜。通过这种方法，我们能够明确ER的生物物理效应。(3)通过腺病毒介导的ER α和β的过表达，研究了雌激素对血管平滑肌细胞增殖的抑制作用与哪一种ER亚型有关。我们发现抑制作用主要是通过Erβ介导的。(4)血管内皮细胞的凋亡可能与动脉粥样硬化病变的发生有关。我们发现雌激素能减轻内皮细胞的凋亡。这种作用部分是通过下调Bax表达介导的。(5)肥胖是动脉粥样硬化的重要危险因素之一，雌激素具有抗肥胖作用。我们发现雌激素抑制作用的机制是通过Erβ在中枢神经系统的表达。(6)我们研究了187名日本绝经后妇女Erβ基因上游CA（胞嘧啶-腺嘌呤）重复序列多态性与血压的关系。我们发现一组携带特定CA重复序列的受试者表现出明显的收缩期高血压。

The goal of our study is to elucidate the atheroprotective effects of estrogen, especially the role of estrogen receptor (ER) subtype, and to apply a new therapeutic method using ER to prevent atherosclerosis. We have gained six results for the three years, described below. (1) We examined the influence of diabetes mellitus on atherosclerosis in relation to ER. We showed that the expression of Erα was decreased in high glucose state in cultured vascular smooth muscle cells, mediated through the activation of protein kinase C. (2) We successfully constructed transgenic mouse overexpressing mutant ER which has a dominant negative transcriptional activity to both Erα and Erβ. Neointima was formed in this mouse by placing polyethylene cuff around the femoral artery. By this method, we were able to clarify the biophysical effect of ER. (3) We examined which ER subtype was involved in the inhibitory effect of estrogen on vascular smooth muscle cell proliferation using adenovirus-mediated overexpression of Erα and β. We found that the inhibitory effect was mediated mainly via Erβ. (4) Apoptosis of vascular endothelium is supposed to be related to the initiation of atherosclerotic lesion. We showed that estrogen attenuated apoptosis of endothelium. This effect was mediated, in part, through the downregulation of Bax expression. (5) Obesity is one of the important risk factors for atherosclerosis, and estrogen has anti-obese effect. We found that the mechanism of the inhibitory effect of estrogen is through Erβ expressed in the central nervous system. (6) We investigated the association between the polymorphism of CA (cytosine-adenine) repeat in the upstream of Erβ gene and blood pressure in 187 Japanese postmenopausal women. We found that a group of subjects who bears a specific CA repeats showed significant systolic hypertension.