NAD metabolism and mitochondrial dysfunction in ALS models

ALS 模型中的 NAD 代谢和线粒体功能障碍

• 批准号: 10084091
• 负责人: Marcelo R Vargas
• 金额: $ 18.92万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-01 至 2020-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10084091
• 关键词: NAD; metabolism; mitochondrial; dysfunction; ALS

 DESCRIPTION (provided by applicant): The long-term goal of the proposal is to develop new therapeutic strategies using mechanistic insights drawn from understanding astrocyte-motor neuron interaction in amyotrophic lateral sclerosis (ALS). In particular, the primary objective of this proposal is to establish whether increased nicotinamide adenine dinucleotide (NAD) availability ameliorates motor neuron degeneration in ALS models. ALS or Lou Gehrig's disease accounts for about 1 in 500 to 1 in 1,000 adult deaths in the United States and is caused by the progressive degeneration of motor neurons in the spinal cord, brain stem, and motor cortex. Motor neuron death leads to muscle weakness and paralysis causing death in one to five years from the time of symptoms onset. Most ALS cases are sporadic (SALS) and exposure to yet unidentified environmental toxicants might be responsible for SALS. About 5-10% of the cases are inherited (familial ALS, FALS) but FALS and SALS are phenotypically indistinguishable, and a significant share of our understanding come from the study of rodent models over-expressing ALS-linked mutant human superoxide dismutase 1 (hSOD1). Primary astrocytes isolated from mutant hSOD1 over-expressing mice induce motor neuron death in co-culture, and it has been demonstrated that astrocytes differentiated from spinal cord autopsy-derived neuronal progenitor cells from FALS and SALS patients are also toxic for motor neurons in co-culture. Sirtuins are a family of enzymes capable of catalyzing NAD-dependent deacylation and mono(ADPribosyl)ation reactions. Remarkably, NAD- dependent sirtuin-mediated deacetylation has been shown to modulate all major mitochondrial processes. Since mitochondrial dysfunction has been linked to ALS and the toxicity of ALS-astrocytes, we seek to better define the role of NAD-dependent signaling in motor neuron degeneration and determine if the modulation of NAD levels may be a potential therapeutic strategy for ALS. Our ongoing experiments demonstrate that increasing NAD content in ALS-astrocytes reverts its toxicity towards co-cultured motor neurons, while NAD synthesis and NAD-dependent signaling may be compromised in mutant hSOD1 mice. Thus, the specific aims of the proposal are: Aim 1-To determine the role of NAD content in the toxicity of astrocytes expressing ALS- linked mutant hSOD1s toward co-cultured motor neurons. Aim 2-To evaluate the effect of transgenic models with altered NAD synthesis and degradation on the onset and progression of the disease in ALS mouse models. Aim 3-To evaluate the effect of treatment with a key NAD precursor on the onset and progression of the disease in ALS mouse models. The outcome of the proposal will contribute to the current understanding of NAD metabolism and mitochondrial dysfunction in neurodegeneration. More important, since we have shown that therapeutic targets identified in our astrocyte-motor neuron co-culture system have a beneficial effect when translated into animal models of ALS, the proposal is likely to provide in vivo proof of the value of modulating NAD metabolism as a therapeutic target in ALS.

 描述（由申请人提供）：该提案的长期目标是利用从了解肌萎缩侧索硬化症（ALS）中星形胶质细胞-运动神经元相互作用中获得的机制见解来开发新的治疗策略。特别是，该提案的主要目标是。确定增加烟酰胺腺嘌呤二核苷酸 (NAD) 的可用性是否可以改善 ALS 或卢伽雷氏病模型中的运动神经元变性（约占 1%）。在美国，每 1,000 名成年人中就有 500 比 1 的人死亡，是由脊髓、脑干和运动皮层运动神经元的进行性退化引起的。运动神经元死亡会导致肌肉无力和瘫痪，从而在一到五年内死亡。大多数 ALS 病例是散发性的 (SALS)，接触尚未确定的环境毒物可能导致 SALS 的大约 5-10% 是遗传性的（家族性 ALS、 FALS），但 FALS 和 SALS 在表型上是无法区分的，我们的理解很大一部分来自对过表达 ALS 相关突变型人超氧化物歧化酶 1 (hSOD1) 的啮齿动物模型的研究，从突变型 hSOD1 过表达小鼠中分离出原代星形胶质细胞。共培养中运动神经元死亡，并且已证明星形胶质细胞是从脊髓尸检衍生的 FALS 和 SALS 神经元祖细胞分化而来Sirtuins 是能够催化 NAD 依赖性脱酰化和单（ADPribosyl）化反应的酶家族，值得注意的是，NAD 依赖性 Sirtuin 介导的脱乙酰化已被证明可以调节所有主要线粒体。由于线粒体与 ALS 和 ALS 星形胶质细胞的毒性有关，我们寻求更好的功能障碍来定义 NAD 依赖性信号传导在运动神经元变性中的作用，并确定是否。 NAD 水平的调节可能是 ALS 的潜在治疗策略，我们正在进行的实验表明，增加 ALS 星形胶质细胞中的 NAD 含量可恢复其对共培养运动神经元的毒性，而 NAD 合成和 NAD 依赖性信号传导可能会在突变 hSOD1 中受到损害。因此，该提案的具体目标是： 目标 1-确定 NAD 含量在表达 ALS 连接突变型 hSOD1 的星形胶质细胞对共培养运动神经元的毒性中的作用。 2-评估 NAD 合成和降解改变的转基因模型对 ALS 小鼠模型疾病发生和进展的影响 目标 3-评估关键 NAD 前体治疗对疾病发生和进展的影响。该提案的结果将有助于目前对神经退行性疾病中 NAD 代谢和线粒体功能障碍的理解，因为我们已经表明，在我们的星形胶质细胞-运动神经元共培养系统中确定的治疗靶点具有有益的作用。翻译时在 ALS 动物模型中，该提案可能会提供体内证据，证明调节 NAD 代谢作为 ALS 治疗靶点的价值。