Nongenomic Signaling Mechanisms of Environmental Estrogens

干扰内分泌的化学物质，如环境雌激素，污染我们的周围环境，损害我们的健康。 动物的生殖健康，可能还有人类。这些化合物可能充当不适当的雌激素，和/或 干扰内源性雌激素的作用，但其作用机制低，环境相关 浓度基本上是未知的。我们最近表明，信号级联导致诱导功能 由雌二醇（E2）在质膜上启动的雌激素受体也可由非生理性雌激素有效启动 （异种雌激素）。在表达膜型雌激素受体a（mER a）的细胞中， 通过激活细胞外调节激酶（ERK）引发独特的信号传导模式（时间，剂量反应） 和/或钙升高。我们现在将解决（1）激活mER a以产生 信号及其相关功能，通过比较具有不同碳- 链长和结构，和突出的生理雌激素（E2，雌三醇和雌酮）;（2）活性 烷基酚通过加和、协同和 拮抗机制;（3）这些反应的G蛋白偶联。G蛋白可能位于 我们以前的工作和其他人的信号反应。我们现在要寻找G蛋白亚型的直接证据 通过免疫共沉淀、使用特异性抑制剂和显性阴性G蛋白亚型与mERa相互作用 和诱饵相互作用肽方法。两种生理雌激素作用下G蛋白偶联的变化 和烷基酚类异种雌激素。我们的长期目标是利用我们建立的模型系统， 回答了各种详细的机械问题，关于不同的生理结构的具体结构特征， 雌激素和异种雌激素亚类通过非基因组途径和mER α影响作用， 扰乱内分泌过程健康相关性：了解环境雌激素如何破坏正常信号传导， 生殖功能将使我们能够设计新的预防和治疗战略，以应对其毒性。 证明它们的低剂量效应也将指导重新评估联邦规定的法律的污染 环境雌激素的限制。环境雌激素促进的程度和机制 必须了解雌激素过量的疾病（如乳腺癌和垂体癌，不孕症）， 可以限制在安全水平。

Endocrine-disrupting chemicals such as environmental estrogens contaminate our surroundings and impair the reproductive health of animals, and probably humans. These compounds may act as inappropriate estrogens, and/or interfere with the actions of endogenous estrogens, but their mechanisms of action at low, environmentally relevant concentrations are largely unknown. We have recently shown that signal cascades leading to induced functions initiated by estradiol (E2) at the plasma membrane are also potently initiated by nonphysiological estrogens (xenoestrogens). In cells that express a membraneform of the estrogen receptor-a (mERa), each xenoestrogen elicited unique signaling patterns (temporal, dose-response) via activation of extracellular-regulated kinases (ERKs) and/or calcium elevation. We will now address (1) the structural requirements for activating mERa to generate signals and their linked functions, by comparing the effects of alkylphenol xenoestrogens having varying carbon- chain lengths and structures, and prominent physiological estrogens (E2, estriol, and estrone); (2) active alkylphenols' ability of to act in combination with physiological estrogens via additive, synergistic, and antagonistic mechanisms; and (3) the G protein coupling of these responses. G proteins likely lie upstream of the signaling responses shown by our previous work and others'. We will now seek direct evidence for G protein subtype interactions with mERa via co-immunoprecipitation, use of specific inhibitors, and dominant-negative G protein subtype and decoy interaction peptide approaches. Changes in G protein coupling in response to both physiological estrogens and alkylphenol xenoestrogens will be examined. Our long-term objective is to use our established model system to answer a variety of detailed mechanistic questions about how specific structural features of different physiological estrogens and xenoestrogen subclasses affect actions through the nongenomic pathway and the mERa, and thereby disrupt endocrine processes. Health relevance: Knowing how environmental estrogens disrupt normal signaling and reproductive functions will enable design of new prevention and treatment strategies to deal with their toxicity. Demonstrating their low-dose effects will also guide re-evaluation of Federal regulations setting legal contamination limits for environmental estrogens. The extent and mechanisms by which environmental estrogens contribute to diseases of estrogen overexposure (eg.breast and pituitary cancers, infertility) must be understood so that exposures can be limited to safe levels.