Imaging Cell Signaling Events During Luteinizing Hormone Pulses

描述(申请人提供)：随着年龄的增长，黄体生成素(LH)水平的升高与阿尔茨海默病(AD)的发展有关；来自临床研究的证据表明，用促性腺激素释放激素(GnRH)拮抗剂Lupron治疗患者可以降低LH水平，减缓AD的进展并改善认知功能。虽然已经有研究表明黄体生成素对小鼠大脑和M17细胞中淀粉样蛋白的加工有影响，但令人惊讶的是，关于黄体生成素对神经系统的直接影响知之甚少。最近关于这个问题的研究使用了固定浓度的黄体生成素，而忽略了黄体生成素的分泌，特别是在女性中，具有强烈的脉动性，而且年龄对黄体生成素脉冲的幅度有影响。在这里，我们建议检查高幅度的黄体生成素脉冲对神经母细胞瘤细胞系M17细胞的影响，该细胞系表达黄体生成素受体并从其前体处理淀粉样蛋白。将对年轻女性和绝经后女性的黄体生成素受体脉冲进行比较。我们假设，M17神经母细胞瘤细胞以绝经后妇女特有的幅度暴露于促黄体生成素脉冲，显著增加淀粉样蛋白的分泌，这是一种在AD患者大脑中出现过量的蛋白质。这些研究还将首次开发与激素暴露期间活细胞中促黄体生成素介导的信号相关的成像事件的策略。出于几个原因，我们为此应用程序选择了R03机制。该项目涉及“新研究技术的开发”，这是NICHD R03资助机制的一个目标。对此R03应用程序的支持将允许对几种实时监测促黄体生成素受体功能的生物物理方法进行原则证明。这些方法将被合并到R01应用程序中，该应用程序包含对卵巢细胞响应排卵前促黄体生成素脉冲和促黄体生成素激增的信号的详细检查。此外，这个项目的范围有限，很可能在两年内完成。国家老龄研究所的老龄生物学计划(BAP)对该项目的共同支持也可能是适当的。随着年龄的增长，黄体生成素搏动性的变化与AD的发生有关，因此代表着一种可能是老年人群中高发疾病的危险因素的“不利变化”。

DESCRIPTION (provided by applicant): Elevations of luteinizing hormone (LH) levels with aging have been implicated in the development of Alzheimer's Disease (AD); evidence from clinical studies suggests that treatment of patients with a GnRH antagonist, Lupron, reduces LH levels, slows the progression of AD and improves cognitive function. Although there have been studies implicating LH effects on processing of amyloid-¿ in the murine brain and M17 cells, there is surprisingly little known about direct effects of LH on the nervous system. Recent studies addressing this question have used fixed concentrations of LH and ignored the fact that LH secretion, particular in women, is strongly pulsatile and that there are effects of aging on the amplitude of LH pulses. Here we propose to examine the effects of high amplitude LH pulses on M17 cells, a neuroblastoma cell line which expresses LH receptors and processes amyloid-¿ from its precursor. LH receptor pulses characteristic of young women and of post-menopausal women will be compared. We hypothesize that exposure of M17 neuroblastoma cells to LH pulses at amplitudes characteristic of those in post-menopausal women significantly increases the secretion of amyloid-¿, a protein that appears in excess in the brains of patients with AD. These studies will also develop, for the first time, strategies for imaging events associated with LH-mediated signaling in living cells during exposure to hormone. We have chosen the R03 mechanism for this application for several reasons. This project involves the "development of new research technology", a goal of the NICHD's R03 funding mechanism. Support for this R03 application will permit a proof-of-principal demonstration of several biophysical approaches to monitor LH receptor function in real time. These approaches will be incorporated into an R01 application containing a detailed examination of signaling by ovarian cells in response to pre-ovulatory LH pulses and the LH surge. In addition, this project is of limited scope and likely to be completed within two years. Shared support for this project from the Biology of Aging Program (BAP) in the National Institute of Aging might also be appropriate. Changes in LH pulsatility with aging are implicated in the development of AD and thus represent an "adverse change" that may be a risk factor for development of a disease that occurs with high frequency in an aging population.