APOE genotype and sex dependent effects of 17-alpha-estradiol on AD pathology

 描述（由申请人提供）：阿尔茨海默病（AD）的特征在于尸检时大脑皮层区域中含有高密度β-淀粉样蛋白（AAPs）的斑块和广泛的神经胶质增生，伴有神经元严重缺失，包括海马CA亚区中的锥体神经元和蓝斑（LC）中的去甲肾上腺素能神经元。AD是老年痴呆症的最常见原因，女性AD的发病率高于男性。性类固醇激素的逐渐丧失可能导致与年龄相关的认知能力下降。雌激素在小鼠模型中的神经保护作用已经确立。具体而言，17-β-雌二醇已显示刺激增强的突触可塑性、神经突生长、海马神经发生和长时程增强。然而，其对人类外周靶点的作用限制了β-E2作为潜在疗法的有用性。大型妇女健康倡议记忆研究（WHIMS）的负面结果，一项使用β-E2的临床研究强调了分析非女性化雌激素的迫切需要。最近，我们发现17-α-雌二醇（α-E2），17β-雌二醇的异构体，似乎可以减轻成年dtg APP/PS 1小鼠神经元丢失、淀粉样蛋白负荷和神经胶质细胞增殖的严重程度。为了开始在体内解决这一假设，我们建议确定α-E2在APOE敲入（APOE 3和APOE 4）和5x FAD小鼠中的神经保护作用的机制。使用相同数量的雄性和雌性小鼠，我们将通过皮下颗粒在60天内递送αE2。随后处死动物并取出大脑，以确定αE2的神经保护作用是否是介导的 以性别和/或apoE基因型依赖的方式。这些研究的终点将是计算机体视学，以量化CA 1和LC中的神经元损失、海马结构中的淀粉样蛋白负荷和神经胶质细胞增殖;以及酶联免疫测定，以量化海马分子层中的ARF肽和促炎细胞因子的水平。总之，这些实验将可能为αE2在APOE基因敲入（APOE 3和APOE 4）和5x FAD小鼠中的神经保护作用提供最直接的细胞部位体内评估。结果将评估αE2是否值得进一步研究，作为治疗中老年男性和女性AD的潜在策略。

 DESCRIPTION (provided by applicant): Alzheimer's disease (AD) is characterized at post-mortem examination by high densities of ß-amyloid (Aß)-containing plaques and extensive neurogliosis in cortical brain regions, with severe loss of neurons, including the pyramidal neurons in the CA sub-regions of the hippocampus and noradrenergic neurons in the locus coeruleus (LC). AD is the most common cause of elderly dementia and women have a higher incidence of AD than men. The gradual loss of sex steroid hormones may contribute to age associated cognitive decline. A neuroprotective role of estrogens in murine models has been established. Specifically, 17-β-estradiol has been shown to stimulate enhanced synaptic plasticity, neurite growth, hippocampal neurogenesis and long-term potentiation. However, its effects on peripheral targets in humans limit the usefulness of β-E2 as a potential therapy. Negative outcomes from the large Women's Health Initiative Memory Study (WHIMS), a clinical study using β-E2 highlight the dire need to analyze non-feminizing estrogens. Recently, we discovered that 17-α-estradiol (α-E2), an isomer of 17β-estradiol, appear to mitigate the severiy of neuron loss, amyloid burden, and neuroglial proliferation in adult dtg APP/PS1 mice. To begin to address this hypothesis in-vivo, we propose to identify mechanisms for the neuroprotective effects of α-E2 in APOE knock in (APOE3 and APOE4) and 5x FAD mice. Using equal numbers of both male and female mice, we will deliver αE2 over sixty days via subcutaneous pellets. Sacrifice and brain removal will follow to identify if neuroprotective effects of αE2 are mediated in a sex and/or apoE genotype dependent manner. Endpoints for these studies will be computerized stereology to quantify neuron loss in CA1 and LC, amyloid burden and neuroglial proliferation in the hippocampal formation; and enzyme-linked immunoassays to quantify levels of Aß peptides and pro-inflammatory cytokines in hippocampal molecular layers. Taken together, these experiments will provide perhaps the most direct in-vivo assessment of cellular sites for αE2's neuroprotective effects in APOE knock-in (APOE3 and APOE4) and 5x FAD mice. Results will assess whether αE2 deserves further study as a potential strategy for the therapeutic management of AD in middle-aged and elderly men and women.