Respiratory Dysfunction in an Optineurin knock out ALS mouse model

7.项目摘要/摘要 肌萎缩侧索硬化症(ALS)是一种毁灭性的、致命的神经退行性疾病，目前尚无治愈方法。 局灶性无力最终发展为全身性肌肉无力和瘫痪，但这些疾病的确切病因 事件仍未可知。许多患者最终死于通风不足、缺氧、 和呼吸衰竭。最近，视神经磷酸酶(optineurin，OPTN)基因被发现与 肌萎缩侧索硬化症的神经变性。OPTN突变患者的ALS发病年龄在30至60岁之间， 在最终死于呼吸衰竭之前，他们有一种缓慢发展的疾病。OPTN的病因学研究 缺乏引起的呼吸衰竭仍然未知，并将是本申请的目标1的重点。此外, 在目标2中，我们将观察低氧(或低氧水平)对疾病发生和发展的影响。在……里面 肌萎缩侧索硬化症，呼吸肌进行性无力导致的呼吸障碍导致慢性间歇 缺氧。然而，在诊断之前，我们认为缺氧也可能在引发疾病中发挥作用。 OPTN缺乏症患者的发病和加重运动无力。在细胞水平上，低氧诱导 线粒体降解，激活自噬，诱导细胞死亡。有趣的是，OPTN调节 线粒体降解、自噬和细胞死亡。由于OPTN在调节自噬方面是必不可少的，我们 提出在没有OPTN的情况下，慢性间歇性低氧(CIH)的影响将被放大，并将 导致呼吸运动神经元的蛋白质聚集和细胞破坏。这种扰乱将进一步 加重呼吸障碍。因此，推动这一提议的基本假设是OPTN 缺乏会损害呼吸功能，而接触CIH会引发早期疾病发作和 加速呼吸道病理。为了验证我们的假设，我们将使用OPTN基因敲除小鼠(OPTN-/-) 由Henry Tseng(co-I)生成。与ALS患者经历的病理相似，这些小鼠表现出缺陷 随着年龄的增长而逐渐恶化的平衡、协调和运动障碍。OPTN-/-小鼠提供了一种 这是研究压力依赖机制的重要机会和理想工具 肌萎缩侧索硬化症的神经退行性变和呼吸功能。使用OPTN将实现两个具体目标-/- 小鼠模型：目的1：确定OPTN缺乏对呼吸功能和呼吸的影响 肌萎缩侧索硬化症的运动神经元、神经和肌肉和目标2：评估脑出血对疾病发生和发展的影响 OPTN缺乏症的进展。拟议的实验涉及对呼吸系统的全面评估 功能包括自主呼吸和呼吸神经输出，以及生化和组织学 呼吸运动单元的评估。这份R21提案将结合呼吸生理学和ALS 小鼠模型的PI(ElMallah)经验，具有神经生物学和视神经磷酸酶经验的co-I (曾)。 项目摘要/摘要第1页

7. PROJECT SUMMARY/ABSTRACT Amyotrophic Lateral Sclerosis (ALS) is a devastating and fatal neurodegenerative disease with no current cure. Focal weakness eventually progresses to global muscle weakness and paralysis, but the exact etiology of these events remains unknown. Many patients die when they ultimately succumb to inadequate ventilation, hypoxia, and respiratory failure. Recently, the gene for optineurin (OPTN) was found to be associated with neurodegeneration in ALS. Patients with OPTN mutations show an onset of ALS from 30 to 60 years of age and have a slowly progressive disease before they eventually die of respiratory failure. The etiology of OPTN deficiency induced respiratory failure remains unknown and will be a focus of Aim 1 of this application. In addition, in Aim 2, we will look at the impact of hypoxia (or low oxygen levels) on disease initiation and progression. In ALS, impaired breathing due to progressive weakness of the respiratory muscles leads to chronic intermittent hypoxia. However, prior to diagnosis, we propose that hypoxia may also play a role in triggering the disease onset and exacerbating motor weakness in OPTN deficient patients. At the cellular level, hypoxia induces mitochondrial degradation, activates autophagy and induces cell death. Interestingly, OPTN regulates mitochondrial degradation, autophagy and cell death. Since OPTN is essential in regulating autophagy, we propose that in the absence of OPTN, the effects of chronic intermittent hypoxia (CIH) will be amplified and will result in protein aggregation and cellular disruption in respiratory motoneurons. This disruption will further exacerbate breathing impairment. Thus, the fundamental hypothesis driving this proposal is that OPTN deficiency impairs respiratory function, and exposure to CIH triggers early disease onset and accelerates respiratory pathology. In order to test our hypothesis, we will use OPTN knock out mice (Optn-/-) generated by Henry Tseng (co-I). Similar to pathology experienced by ALS patients, these mice exhibit deficits in balance, coordination, and motor impairment that progressively deteriorates with age. Optn-/- mice provide an important opportunity and an ideal tool to study stress-dependent mechanisms that exacerbate neurodegeneration and respiratory function in ALS. Two specific aims will be accomplished using the Optn-/- mouse model: Aim 1: To identify the impact of OPTN deficiency on respiratory function and respiratory motoneurons, nerves, and muscle in ALS and Aim 2: To assess the impact of CIH on disease onset and progression in OPTN deficiency. The proposed experiments address a comprehensive evaluation of respiratory function including spontaneous breathing and respiratory nerve output, as well as biochemical and histological assessment of respiratory motor units. This R21 proposal will combine the respiratory physiology and ALS mouse model experience of the PI (ElMallah), with the neurobiology and optineurin experience of the co-I (Tseng). Project Summary/Abstract Page 1