RLIP, Mitochondrial Dysfunction in Alzheimer’s Disease

项目摘要 阿尔茨海默病（Alzheimer's disease，AD）是一种神经退行性疾病，影响很大比例的老年人， 人口尽管它的流行，没有具体的治疗方法可以预防或治疗这种疾病。研究 疾病的病理生理学和新药的测试仅限于携带 AD相关基因的突变形式，包括APP、PSEN 1、APOE β 4和ob（瘦素）。由于氧化 脑中的应激（OS）被认为参与AD发病机制，OS的标志物如蛋白质 氧化、脂质氧化、DNA氧化、糖氧化和线粒体功能障碍也可具有作为 AD的标记。RalBP 1（Rlip）是一种应激激活蛋白，在OS防御中起着至关重要的作用， 确定GSH结合的氧化代谢物流出中的酶。虽然我们有广泛的 Rlip作为一种重要的氧化应激防御机制， 癌症、代谢综合征和糖尿病，我们只是最近才开始研究它在神经元中的功能。我们 初步数据和发表的文章表明，在神经元细胞和Rlip小鼠中敲除Rlip， 与AD中的氧化应激/线粒体功能障碍和突触损伤有很强的机制联系。此外，本发明还 Rlip缺陷小鼠和神经元的脑中OS增加，NRF 2下调，OS 正常情况下会上调。这种失调的NRF 2反应可能有助于进一步加剧氧化应激。 应激、外源性物质代谢受损和线粒体功能失调。我们提供 有趣的初步证据表明，人类死后AD大脑中Rlip缺乏， 线粒体结构，功能和蛋白质在Rlip缺陷小鼠和Rlip缺陷神经元的培养。 我们的初步研究表明，Rlip缺失在表观遗传学上调节了几个AD连锁基因，包括 CREBBP，一个与神经认知有关的基因。Rlip+/-模型将使我们能够发展一种氧化应激 AD的动物模型，这反过来将有助于开发用于治疗AD的药物， 进行研究，将导致新的发现，对AD生物学。根据初步调查结果，我们 假设Rlip缺乏引起氧化应激，这加剧了神经变性， 神经认知功能失调;因此，通过Rlip减少氧化应激信号传导 上调可能会改善线粒体和突触功能以及认知行为。根据拟议的 目的：1）我们将研究Rlip基因敲除小鼠是否具有神经认知、组织病理学、生化和 与人源化Aβ基因敲入（hAβ-KI）小鼠相似的神经元缺陷，以及2）Rlip是否 上调改善了hAβ-KI模型的表型严重程度。这些研究将提供新的见解 调节AD中的氧化应激防御，并可能导致AD的新治疗方法。

PROJECT SUMMARY Alzheimer's disease (AD) is a neurodegenerative disorder that affects a large proportion of the aging population. Despite its prevalence, no specific treatments can prevent or treat this disease. Research on the pathophysiology of the disease and the testing of new drugs is limited to transgenic mouse models harboring mutated versions of AD-related genes, including APP, PSEN1, APOEɛ4, and ob (leptin). Since oxidative stress (OS) in the brain is believed to be involved in AD pathogenesis, markers of OS such as protein oxidation, lipid oxidation, DNA oxidation, glycoxidation, and mitochondrial dysfunction may also have utility as markers for AD. RalBP1 (Rlip) is a stress-activated protein that plays a crucial role in OS defense as the rate- determining enzyme in the efflux of the GSH-conjugated oxidative metabolites. While we have extensively characterized the role of Rlip as a centrally important oxidative stress-defense mechanism in the etiologies of cancer, metabolic syndrome, and diabetes, we have only recently begun to study its function in neurons. Our preliminary data and published suggests that the Rlip knockout in neuronal cells and Rlip mice developed strong mechanistic links with oxidative stress/mitochondrial dysfunction and synaptic damage in AD. Further, Rlip deficient mice and neurons have increased OS in the brain and downregulation of NRF2, which OS normally up-regulates. This dysregulated NRF2 response likely contributes to further exacerbated oxidative stress, impaired xenobiotic metabolism, and dysregulated mitochondrial functions in these mice. We provide intriguing preliminary evidence of Rlip deficiency in human postmortem AD brains and abnormalities of mitochondrial structure, function, and proteins in Rlip deficient mice and in Rlip deficient neurons in culture. Our preliminary studies show that Rlip depletion epigenetically regulates several AD-linked genes, including CREBBP, a gene implicated in neurocognition. The Rlip+/- model will allow us to develop an oxidative stress animal model of AD, which in turn will be helpful in the development of drugs for the treatment of AD and in conducting studies that will lead to novel findings on AD biology. Based on our preliminary findings, we hypothesize that Rlip deficiency causes oxidative stress, which exacerbates neurodegeneration and dysregulation of neurocognitive functions; therefore, reducing oxidative stress signaling through Rlip upregulation may improve mitochondrial and synaptic functions and cognitive behavior. Under the proposed Aims 1) we will study whether Rlip knockout mice have neurocognitive, histopathological, biochemical, and neuronal deficits resembling those seen in humanized Aβ knock-in (hAβ-KI) mice, and 2) whether Rlip upregulation ameliorates the phenotypic severity of the hAβ-KI model. These studies will offer novel insights into the regulation of oxidative stress defenses in AD and may lead to new treatments for AD.