Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267-0575, USA.
Endocrinology. 2010 Dec;151(12):5689-99. doi: 10.1210/en.2010-0710. Epub 2010 Oct 6.
Estrogenic endocrine disrupting chemicals (EDCs) constitute a diverse group of man-made chemicals and natural compounds derived from plants and microbial metabolism. Estrogen-like actions are mediated via the nuclear hormone receptor activity of estrogen receptor (ER)α and ERβ and rapid regulation of intracellular signaling cascades. Previous study defined cerebellar granule cell neurons as estrogen responsive and that granule cell precursor viability was developmentally sensitive to estrogens. In this study experiments using Western blot analysis and pharmacological approaches have characterized the receptor and signaling modes of action of selective and nonselective estrogen ligands in developing cerebellar granule cells. Estrogen treatments were found to briefly increase ERK1/2-phosphorylation and then cause prolonged depression of ERK1/2 activity. The sensitivity of granule cell precursors to estrogen-induced cell death was found to require the integrated activation of membrane and intracellular ER signaling pathways. The sensitivity of granule cells to selective and nonselective ER agonists and a variety of estrogenic and nonestrogenic EDCs was also examined. The ERβ selective agonist DPN, but not the ERα selective agonist 4,4',4'-(4-propyl-[1H]-pyrazole-1,3,5-triyl) trisphenol or other ERα-specific ligands, stimulated cell death. Only EDCs with selective or nonselective ERβ activities like daidzein, equol, diethylstilbestrol, and bisphenol A were observed to induce E2-like neurotoxicity supporting the conclusion that estrogen sensitivity in granule cells is mediated via ERβ. The presented results also demonstrate the utility of estrogen sensitive developing granule cells as an in vitro assay for elucidating rapid estrogen-signaling mechanisms and to detect EDCs that act at ERβ to rapidly regulate intracellular signaling.
雌激素类内分泌干扰化学物质（EDCs）构成了一组多样化的人造化学物质和天然化合物，它们源自植物和微生物代谢。雌激素样作用是通过核激素受体雌激素受体（ER）α和 ERβ的活性以及细胞内信号级联的快速调节来介导的。先前的研究将小脑颗粒细胞神经元定义为雌激素反应性，并且颗粒细胞前体细胞的活力对雌激素在发育上是敏感的。在这项研究中，使用 Western blot 分析和药理学方法的实验，描述了选择性和非选择性雌激素配体在发育中的小脑颗粒细胞中的受体和信号作用模式。发现雌激素处理会短暂增加 ERK1/2 的磷酸化，然后导致 ERK1/2 活性的长期抑制。发现颗粒细胞前体细胞对雌激素诱导的细胞死亡的敏感性需要膜和细胞内 ER 信号通路的整合激活。还检查了颗粒细胞对选择性和非选择性 ER 激动剂以及各种雌激素和非雌激素 EDC 的敏感性。选择性 ERβ激动剂 DPN，但不是 ERα 选择性激动剂 4,4',4'-(4-丙基-[1H]-吡唑-1,3,5-三基)三苯酚或其他 ERα 特异性配体，刺激细胞死亡。只有具有选择性或非选择性 ERβ 活性的 EDC，如大豆黄酮、雌马酚、己烯雌酚和双酚 A，被观察到诱导与 E2 相似的神经毒性，支持了在颗粒细胞中雌激素敏感性是通过 ERβ 介导的结论。所呈现的结果还表明，雌激素敏感的发育中的颗粒细胞作为体外测定法，可用于阐明快速的雌激素信号机制，并检测作用于 ERβ 以快速调节细胞内信号的 EDC。
