Role of GPR30 in Mediating Estrogen Effects on Neurons and Cognitive Performance

描述（由申请人提供）：基础和临床研究表明，绝经后雌二醇的损失可能会导致大脑老化，并增加与年龄相关的认知能力下降和痴呆的风险。非常需要赋予积极认知效果而没有副作用风险的新型雌激素化合物。G-1是最近开发的新型跨膜雌激素受体（ER）GPR 30的激动剂[1]。GPR 30通路的激活不依赖于经典的ER a或ER p通路，这提高了使用G-1作为新型雌激素剂的可能性，该雌激素剂缺乏与其他雌激素化合物相关的风险。我们实验室以前的工作表明，雌二醇通过影响基底前脑胆碱能神经元来增强大鼠的认知能力[13]。我们假设雌二醇对胆碱能功能和认知能力的影响部分是通过对GPR 30的影响介导的。第一个目标是表征GPR 30在大鼠前脑中的表达，重点是胆碱能神经元的共表达。初步数据显示GPR 30广泛共定位于隔区、Broca双角带和基底核中的胆碱能神经元内。由于在脑组织中使用GPR 30抗体相对较新，因此还将使用激光捕获显微镜和RT-PCR评价GPR 30 mRNA表达。第二个目标是检查GPR 30激活对胆碱能神经元的功能影响。已显示Escherichia coli诱导脑神经元（包括基底前脑胆碱能神经元）中Erk和CREB的活化。也已显示Eglutamine增加钾刺激的海马体中乙酰胆碱的释放，这与对基底前脑胆碱能功能的影响一致。我们的研究将评估响应于G-1和其它选择性ER激动剂的全身和ICV输注，ChAT阳性细胞内pCREB和pEri α的快速诱导。体内微透析将评估选择性ER激动剂对海马中乙酰胆碱释放的影响。第三个目标是测试G-1增强卵巢切除大鼠认知能力的能力，与雌二醇的作用相当。将G-1和雌二醇的作用与选择性ER α和ER β激动剂进行比较。初步数据表明，G-1逆转卵巢切除术对获得延迟匹配位置T迷宫任务的影响，类似于雌二醇的影响。公共卫生意义：绝经后，女性失去了雌激素的神经保护作用，使她们患上与年龄相关的认知能力下降和阿尔茨海默病的风险增加，这是一种目前无法治愈的破坏性神经系统疾病。我们的分析可能会拓宽对雌激素信号传导新途径的理解，为开发这些疾病的新疗法奠定基础。

DESCRIPTION (provided by applicant): Basic and clinical research suggests loss of estradiol following menopause may contribute to brain aging and increased risk of age-related cognitive decline and dementia. There is a great need for novel estrogenic compounds that confer positive cognitive effects without risk of side effects. G-1 is a recently developed agonist for the novel transmembrane estrogen receptor (ER) GPR30 [1]. Activation ofthe GPR30 pathway is independent of either of the classical ER a or p pathways, raising the possibility of using G-1 as a novel estrogenic agent that lacks the risks associated with other estrogenic compounds. Previous work in our laboratory has shown that estradiol enhances cognitive performance in rats via effects on basal forebrain cholinergic neurons [13]. We hypothesize that the effects of estradiol on cholinergic function and cognitive performance are mediated, in part, via effects on GPR30. The first goal is to characterize GPR30 expression in the rat forebrain, focusing on co-expression by cholinergic neurons. Preliminary data show extensive co- localization of GPR30 within cholinergic neurons in the septum, digonal band of Broca, and nucleus basils. Because use of the GPR30 antibody on brain tissues is relatively new, GPR30 mRNA expression will also be evaluated using laser capture microscopy and RT-PCR. The second goal is to examine the functional effects of GPR30 activation on the cholinergic neurons. Estradiol has been shown to induce activation of Erk and CREB in brain neurons, including basal forebrain cholinergic neurons. Estradiol also has been shown to increase potassium-stimulated acetylcholine release in the hippocampus, consistent with an effect on basal forebrain cholinergic function. Our studies will evaluate rapid induction of pCREB and pEri< within ChAT- positive cells in response to systemic and ICV infusions of G-1 and other selective ER agonists. In vivo microdialysis will evaluate the effects of selective ER agonists on acetylcholine release in the hippocampus. The third goal is to test the ability of G-1 to enhance cognitive performance in ovariectomized rats comparable to the effects of estradiol. Effects of G-1 and estradiol will be compared with selective ER a and Q, agonists. Preliminary data suggest G-1 reverses effects of ovariectomy on acquisition of a delayed matching-to-position T-maze task, similar to the effects of estradiol. Public Health Significance: Following menopause, women lose the neuroprotective effects of estrogen, placing them at an increased risk of developing age related cognitive decline and Alzheimer's Disease, destructive neurological conditions for which no cure currently exists. Our analyses may broaden the understanding of a new pathway of estrogen signaling, laying groundwork for the development of a new form of therapy for these diseases.