Preserving mitochondrial function for alleviating ALS progression

项目摘要 肌萎缩侧索硬化症(ALS)是一种无法治愈的致命神经肌肉疾病。大多数肌萎缩侧索硬化症是零星的 没有确定遗传原因的病例。然而，脊髓和肌肉的尸检/活检样本来自 散发性和家族性肌萎缩侧索硬化症患者均表现出明显的形态和生化特征缺陷。 线粒体。这表明线粒体异常是神经肌肉退行性变的常见因素。 尽管有病因学。在过去的12年里，我们使用ALS小鼠模型(G93A)进行的研究建立了一个 骨骼肌线粒体功能障碍是ALS发病机制的一部分。肌肉出现 成为ALS突变的主要目标，除了成为神经元撤退的受害者，因为 肌萎缩侧索硬化症患者肌肉中线粒体缺陷对神经肌肉接头(NMJ)重构的反馈作用。因此， 恢复线粒体功能是缓解ALS全身症状的合理途径 修复一种常见的病理。我们做了一个新奇的发现，ALS的进展包括肠道渗漏和 G93A小鼠微生物群失衡(微生态失调)。这种肠道缺陷发生在肌萎缩侧索硬化症发病之前。 神经肌肉症状，表明肠道缺陷可能在ALS的进展中起作用。我们报道了 G93A小鼠的结肠含有较少的丁酸产生菌，饲料中添加丁酸 减轻G93A小鼠的肠道缺陷，改善它们的神经肌肉性能，延长它们的寿命。 因此，我们的研究提出了一个新的概念，即恢复肠道内稳态可能提供一种替代手段 改善神经肌肉功能治疗肌萎缩侧索硬化。自最初提交以来，我们与布罗托的合作 实验室有了几个令人兴奋的新发现。我们鉴定了ROS相关生物活性的改变的脂组学图谱 G93A小鼠补充1个月丁酸盐后，肌肉中的脂质(BLS)得到恢复。此外， 丁酸盐治疗直接增强了肌肉的收缩能力。我们的初步数据还显示，丁酸盐 治疗改善G93A细胞线粒体功能及其对氧化应激损伤的易感性 肌肉纤维。我们的数据表明，丁酸可能是调节神经肌肉肠道的重要介质。 综合生理学。我们假设神经肌肉系统和 肠道参与肌萎缩侧索硬化症线粒体功能的进行性丧失和丁酸的恢复。 相关微生物组对ALS的治疗有保护线粒体功能的作用。这个 拟议的研究将解决两个基本问题：肠道缺陷如何影响线粒体 肌萎缩侧索硬化症的神经肌肉系统功能障碍(目标1)？神经肌肉-肠道信号能否被利用来 改善线粒体功能以减缓ALS进展和/或提高ALS患者的生活质量(目的 2)?虽然肠道动态平衡和微生物群的改变与人类ALS的病理有关，但我们 期待我们的研究将为肌萎缩侧索硬化症研究领域带来新的概念。从这项研究中获得的知识 可能对开发抗击肌萎缩侧索硬化症的新治疗策略具有潜在的翻译意义。

Project Summary Amyotrophic lateral sclerosis (ALS) is a fatal neuromuscular disease without cure. Most ALS are sporadic cases without identified genetic causes. However, the spinal cord and muscle autopsy/biopsy samples from both sporadic and familial ALS patients all show remarkable defects in morphology and biochemical properties of mitochondria. This indicates abnormal mitochondria as a common player in neuromuscular degeneration despite the etiology. Our research using the ALS mouse models (G93A), over the last 12 years, establishes a concept that mitochondrial dysfunction in skeletal muscle is part of the pathogenesis of ALS. Muscle appears to be a primary target of ALS mutation, in addition to being victim of neuronal withdrawal, because mitochondrial defects in muscle feedback to neuromuscular junction (NMJ) remodeling in ALS. Thus, restoration of mitochondrial function is a logical approach to alleviate the systemic symptom of ALS through fixing a common pathology. We made a novel discocery that ALS progression includes a leaky gut with an imbalanced microbiome (dysbiosis) in G93A mice. This gut defects occurs before the onset of ALS neuromuscular symptoms, suggesting that gut defects may play a role in ALS progression. We reported that the colon of G93A mice contained less butyrate-producing bacteria, and the dietary butyrate supplementation alleviated gut defects in G93A mice, improving their neuromuscular performance and extending their life span. Thus, our study brought a new concept that restoring gut homeostasis may provide an alternative means for improving neuromuscular function to treat ALS. Since the original submission, our collaboration with the Brotto Lab made several exciting new discoveries. We identified altered Lipidomics Profiles of ROS-related Bioactive Lipids (BLs) in muscle that were restored by one-month butyrate diet supplementation in G93A mice. Further, butyrate treatment directly enhanced muscle contractility. Our preliminary data also show that butyrate treatment improved mitochondrial function and its susceptibility to oxidative-stress induced damage in G93A muscle fibers. Our data suggest that butyrate could be an important mediator regulating the neuromuscular-gut integrative physiology. We hypothesize that integrative signaling between the neuromuscular system and gut contributes to the progressive loss of mitochondrial function in ALS, and restoration of butyrate- related microbiome has benefits in preserving mitochondrial function for treatment of ALS. The proposed study will address two fundamental questions: How do gut defects contribute to mitochondrial dysfunction of neuromuscular system in ALS (Aim 1)? Can neuromuscular-gut signaling be leveraged to improve mitochondrial function to slow ALS progression and/or improve the life quality of ALS patients (Aim 2)? While altered intestinal homeostasis and microbiome is linked to the human pathology of ALS, we anticipate that our study will bring novel concepts to the ALS research field. Knowledge gained from this study can have potential translational implications for developing new therapeutic strategies for combating ALS.