Environmental Toxins and Uterine Gene Expression

环境毒素和子宫基因表达

基本信息

批准号：
6986776
负责人：
SANJOY K. DAS
金额：
$ 29.49万
依托单位：
VANDERBILT UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
1997
资助国家：
美国
起止时间：
1997-05-01 至 2007-11-30
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): An "early" and a "late" phase estrogenic response in the uterus has been recognized for more than 60 years yet mechanisms involved in their regulation remain controversial. One concept is that an early event(s), occurring within the first 6 h, prepares the uterus for later (18-30 h) increase in DNA synthesis, cell proliferation, and protein synthesis. An alternate view is that the late or growth phase is a result of the continuous presence of a stimulus. Discussion of either concept usually makes the assumption that all of the responses are dependent upon ligand interaction with one of the two estrogen receptor isoforms (ERalpha and ERbeta). However, increased gene expression following injection of estrogen or xenoestrogen, in mice lacking ERalpha, or in which all ER-activity has been suppressed by an estrogen-antagonist, ICI 182,780 (ICI), has shown this to be an oversimplification. Recently we identified several downstream target genes regulated early by estrogens in the uterus by an ER-independent mechanism. Preliminary studies indicated that estradiol-17beta (E2) rapidly activates phosphorylation of ERK1/ERK2 (MAP kinases) in uteri of both wild-type and ERalpha (-/-) mice. Furthermore, we observed that the administration of a selective inhibitor of ERK1/ERK2 activation (SL327), 30 min prior to an E2 injection totally abrogates the early responsive gene expression including uterine wet weights and the late uterotrophic (growth) responses. In contrast, injection of the inhibitor 6 h after E2 injection did not alter the late responses. Collectively, these results positioned us to study early and late estrogenic responses separately and determine the relationship between these two phases. Our hypothesis is that while estrogenic early responses are ER-independent, late responses are ER-dependent, and cooperation between the two phases is necessary for a full complement of estrogenic responses mediated by natural estrogen or xenoestrogen in the uterus. Our specific aims are to determine: 1. Early responses coordinate with the late growth responses for estrogenic actions in the uterus. 2. Molecular interactions of early and late estrogenic responses mediated by ER. 3. Direct consequences of inhibition of early genes in defining the estrogenic responses in uterine cells both in vivo and in vitro by adenoviral vector-driven delivery. 4. Estrogen-dependent early responsive genes function in a coordinated fashion to regulate ER-dependent activities. The results will help us define the relationship and a molecular cross-talk between the two-phase estrogenic responses in the uterus.

描述（由申请人提供）： 60 多年来，人们已经认识到子宫中的“早期”和“晚期”阶段雌激素反应，但涉及其调节的机制仍然存在争议。一个概念是，在最初 6 小时内发生的早期事件，为子宫随后（18-30 小时）DNA 合成、细胞增殖和蛋白质合成的增加做好了准备。另一种观点认为，晚期或生长期是刺激持续存在的结果。对任一概念的讨论通常假设所有反应都依赖于配体与两种雌激素受体亚型（ERα 和 ERβ）之一的相互作用。然而，在缺乏 ERα 或所有 ER 活性均被雌激素拮抗剂 ICI 182,780 (ICI) 抑制的小鼠中，注射雌激素或异雌激素后基因表达增加，表明这种情况过于简单化。最近，我们发现了一些在子宫中通过不依赖于内质网的机制早期受雌激素调节的下游靶基因。初步研究表明，雌二醇-17β (E2) 可快速激活野生型和 ERα (-/-) 小鼠子宫中 ERK1/ERK2（MAP 激酶）的磷酸化。此外，我们观察到，在 E2 注射前 30 分钟施用选择性 ERK1/ERK2 激活抑制剂 (SL327) 完全消除了早期反应基因表达，包括子宫湿重和晚期子宫营养（生长）反应。相反，注射 E2 后 6 小时注射抑制剂并没有改变晚期反应。总的来说，这些结果使我们能够分别研究早期和晚期雌激素反应，并确定这两个阶段之间的关系。我们的假设是，虽然雌激素早期反应是 ER 独立的，但晚期反应是 ER 依赖性的，并且两个阶段之间的合作对于子宫中天然雌激素或异雌激素介导的雌激素反应的完全补充是必要的。我们的具体目标是确定： 1. 子宫内雌激素作用的早期反应与晚期生长反应相协调。 2. ER介导的早期和晚期雌激素反应的分子相互作用。 3.通过腺病毒载体驱动的传递，抑制早期基因在体内和体外子宫细胞雌激素反应中的直接后果。 4. 雌激素依赖性早期反应基因以协调的方式发挥作用，调节 ER 依赖性活动。结果将帮助我们定义子宫内两相雌激素反应之间的关系和分子串扰。