Tissue-specific modulation of Apolipoprotein E in neurodegeneration

项目概要： 阿尔茨海默氏病（AD）和肌萎缩侧索硬化症（ALS）是多方面的、进行性的 神经退行性疾病给患者、医疗服务提供者和公众带来巨大负担 医疗保健系统。目前没有可用于AD或ALS的疾病修饰治疗。虽然 每种疾病的病因都得到了很好的研究，针对疾病发病机制的特征的战略- 例如，在一个实施例中，β-淀粉样蛋白在AD中的临床疗效有限。确定改变进展的新靶点 神经退行性疾病的创新治疗发展所需要的。 AD和ALS是由遗传和环境因素引起的，这些因素改变了下游途径，如脂质 体内平衡作为全身和中枢神经系统（CNS）脂质转运的关键参与者， 与神经变性的发生和进展有关的是载脂蛋白E（ApoE）。的遗传缺失 ApoE减少小鼠的神经病理学，但也导致动脉粥样硬化。因此，尽管它的含义， 由于ApoE在其独特的生物学"池"（即全身和CNS）中的多样功能， 挑战治疗目标。减少单个ApoE池可以避免这个问题。但 系统性或CNS ApoE沉默对神经变性疾病的独立作用尚不清楚。 本提案的目的是确定系统和CNS ApoE池之间的关系，及其 对AD和ALS小鼠疾病进展的影响。该项目将利用化学稳定，自我， 递送小干扰RNA（siRNA），其能够持续地、组织特异性地沉默靶mRNA。 GalNAc-siRNA特异性递送至肝脏（全身性ApoE产生的位点），并且二价（Di）-siRNA递送 在脑室内（ICV）注射后遍及脑和脊髓。 在Anastasia Khvorova（siRNA化学）、Robert Brown（ALS）、Evgeny Rogaev（AD）博士的指导下， 模型）、Andrew Tapper（动物行为学）和托马斯史密斯（神经病理学家），GalNAc-和Di-siRNA将 分别用于沉默肝脏和CNS ApoE，以及对CNS和全身ApoE池的影响，和 将检查AD和ALS表型。在目标1中，将皮下施用靶向ApoE的GalNAc-siRNA。 注射到老鼠体内。在目标2中，靶向ApoE的Di-siRNA将通过ICV注射递送至CNS。两个目标 将利用AD的APP/PSEN1小鼠模型和ALS的SOD1G93A小鼠模型，并将测量 全身和CNS ApoE和胆固醇水平，以及AD和ALS神经病理学和行为2个月 注射后。这些研究将促进对ApoE库在以下背景下如何相互作用的理解： 神经变性，以及对疾病进展的影响。这些发现将为安全和 有效治疗AD、ALS和年龄相关神经退行性疾病中的ApoE。

PROJECT SUMMARY: Alzheimer’s Disease (AD) and Amyotrophic Lateral Sclerosis (ALS) are multifaceted, progressive neurodegenerative conditions that place a monumental burden on patients, providers, and the public healthcare system. No disease-modifying treatments are currently available for either AD or ALS. Although the etiology of each disease is well studied, strategies targeting characteristic features of disease pathogenesis— e.g., beta-amyloid in AD—show limited clinical efficacy. Identification of novel targets that modify progression of neurodegeneration is needed for innovative therapeutic development across neurodegenerative disorders. AD and ALS are caused by genetic and environmental factors that alter downstream pathways like lipid homeostasis. A critical player in systemic and central nervous system (CNS) lipid transport, that is also implicated in the onset and progression of neurodegeneration, is apolipoprotein E (ApoE). Genetic deletion of ApoE reduces neuropathology in mice, but also causes atherosclerosis. Thus, despite its implication in disease, the diverse functionality of ApoE in its distinct biological “pools” (i.e. systemic and CNS) makes it a challenging therapeutic target. Reducing individual ApoE pools may circumvent this issue. However, the independent effects of systemic or CNS ApoE silencing on neurodegenerative diseases are unclear. The goal of this proposal is to determine the relationship between systemic and CNS ApoE pools, and their effects on disease progression in AD and ALS mice. The project will take advantage of chemically-stable, self- delivering small interfering RNAs (siRNAs) that enable sustained, tissue-specific silencing of target mRNA. GalNAc-siRNAs specifically deliver to liver (site of systemic ApoE production), and divalent (Di)-siRNAs deliver throughout the brain and spinal cord after intra-cerebroventricular (ICV) injection. With guidance from Drs. Anastasia Khvorova (siRNA chemistry), Robert Brown (ALS), Evgeny Rogaev (AD models), Andrew Tapper (animal behavior), and Thomas Smith (neuropathologist), GalNAc- and Di-siRNA will be used to silence hepatic and CNS ApoE, respectively, and the effects on CNS and systemic ApoE pools, and AD and ALS phenotypes, will be examined. In Aim 1, GalNAc-siRNA targeting ApoE will be subcutaneously injected into mice. In Aim 2, Di-siRNA targeting ApoE will be delivered to the CNS via ICV injection. Both aims will utilize the APP/PSEN1 mouse model of AD and the SOD1G93A mouse model of ALS, and will measure systemic and CNS ApoE and cholesterol levels, and AD and ALS neuropathology and behavior two months post injection. These studies will advance the understanding of how ApoE pools interact in the context of neurodegeneration, and the effects on disease progression. Such findings will inform strategies for safe and effective therapeutic targeting of ApoE in AD, ALS, and age-related neurodegenerative disorders.