Impact on Reproductive Aging on Neural-Immune Responses

描述(由申请人提供)：本申请的目的是确定卵巢老化对神经炎症的影响。几种免疫细胞类型对雌激素等性腺类固醇激素敏感，绝经后这些卵巢激素的丢失显著影响免疫系统和脑、骨、皮肤和心血管系统等靶器官的炎症反应。我们特别感兴趣的是确定卵巢老化或生殖衰老对血脑屏障和神经炎症反应的影响。炎症被认为是阿尔茨海默氏症和多发性硬化症等神经退行性疾病的病因之一，女性作为一个群体似乎面临着这些疾病的更高风险。通常情况下，血脑屏障保护大脑免受循环免疫细胞及其细胞毒产物的影响。然而，血脑屏障完整性的变化可能会使脆弱的、往往不可替代的神经网络暴露在对它们致命的蛋白质面前。 使用生殖衰老的动物模型，我们已经表明，与年轻成年女性相比，生殖衰老女性的血脑屏障对静脉注射染料的容许性更强。此外，雌激素治疗增加了染料转移到衰老大脑的关键脑区，而抑制了年轻成年女性的染料转移。在我们的前脑损伤研究中，雌激素的作用也出现了类似的二分法，雌激素抑制了年轻女性炎性细胞因子的产生，但加剧了她们在衰老大脑中的水平。基于这些研究，我们的中心假设是卵巢老化增加了血脑屏障的通透性，并增加了前脑的细胞毒性。这一假设将在两个具体目标中得到检验： 具体目标1将测试生殖衰老导致血脑屏障的物理和功能变化的假设，使这种结构对循环免疫细胞和蛋白质更具容许性。具体地说，我们将使用荧光和放射性标记的示踪剂来确定血脑屏障的通透性，并使用蛋白质检测分析来确定血脑屏障的紧密连接蛋白、黏附蛋白和基质裂解酶的变化。 《特定目的2》将检验这样一种假设：与年轻成年动物相比，全身性侮辱将导致生殖衰老动物迅速和/或长期的神经炎症，并导致更大的神经变性。将使用两种系统性侮辱：一种是使用脂多糖注射的实验性脓毒症模型，另一种是与临床相关的炎性侮辱，包括高胆固醇饮食。我们将测量外周器官(肝脏)和特定脑区的炎症介质，由于这种全身损伤而导致的白细胞在大脑中的运输，以及神经细胞的死亡。

DESCRIPTION (provided by applicant): The goal of this application is to determine the impact of ovarian aging on neural inflammation. Several immune cell types are sensitive to gonadal steroids such as estrogen and the loss of these ovarian hormones at menopause significantly affects the immune system and the inflammatory response in target organs such as the brain, bone, skin and cardiovascular system. We are specifically interested in determining the effects of ovarian aging or reproductive senescence on the blood brain barrier and the neural inflammatory response. Inflammation is believed to contribute to the etiology of neurodegenerative diseases such as Alzheimer's and multiple sclerosis, and women as a group appear to be at a higher risk for these diseases. Ordinarily, the brain is protected from circulating immune cells and their cytotoxic products by the blood brain barrier. However, changes in the integrity of the blood brain barrier can exposed fragile, and often irreplaceable, neural networks to proteins that are fatal for them. Using an animal model of reproductive senescence, we have shown that the blood brain barrier of reproductive senescent females is more "permissive" to intravenously injected dye as compared to young adult females. Furthermore, estrogen treatment increases dye transfer into a key brain region of the senescent brain, while suppressing dye transfer in young adult females. A similar dichotomy was seen in estrogen action in our forebrain injury studies, where estrogen suppressed inflammatory cytokine production in young females but exacerbated their levels in the senescent brain. Based on these studies, our central hypothesis is that ovarian aging increases the permeability of the blood brain barrier and increases cytotoxicity in the forebrain. This hypothesis will be tested in two Specific Aims: Specific Aim 1 will test the hypothesis that reproductive aging results in physical and functional changes in the blood brain barrier, causing this structure to become more permissive to circulating immune cells and proteins. Specifically, we will use fluorescent- and radio-labeled tracers to determine permeability of the blood brain barrier, and protein detection assays to determine changes in tight junction proteins, adherence proteins and matrix-cleaving enzymes of the blood brain barrier. Specific Aim 2 will test the hypothesis that systemic insults will result in a rapid and/or prolonged neural inflammation with greater neurodegeneration in reproductive senescent animals as compared to young adult animals. Two systemic insults will be used: an experimental sepsis model using LPS injections and a clinically-relevant inflammatory insult consisting of a high cholesterol diet. We will measure inflammatory mediators in peripheral organs (liver) and specific brain regions, leukocyte trafficking in the brain due to this systemic insult and neuronal cell death.