Pain Mechanisms in Fabry Disease

项目摘要 该项目的中心目标是确定机械的细胞机制， 本发明涉及法布里病（FD）中的超敏反应和疼痛，从而鉴定用于改善疼痛治疗的新靶标。 FD是最常见的溶酶体贮积病。它是由于溶酶体酶α- 半乳糖苷酶A（α-Gal A），导致鞘糖脂在细胞溶酶体内积累 包括背根神经节（DRG）神经元。小纤维神经病变是FD的一个标志。神经病样痛 开始于5岁左右，随年龄增长而增加，并影响60-80%的所有（男性和女性）患者。所述疼痛是 被描述为由发烧、运动、疲劳或压力引发的偶发性“疼痛危象”，以及慢性“永久性”疼痛危象“。 痛苦”我们使用CRISPR/Cas9删除编码α-Gal A的基因，建立了FD转基因大鼠模型。 法布里病大鼠密切概括了患者中观察到的许多表型，包括血清α- 半乳糖基鞘糖脂，自发和机械诱发的疼痛行为，明显的脂质 小直径DRG神经元中α-半乳糖基鞘糖脂的包涵体和异常积聚， 严重的听力损失Fabry大鼠感觉神经元胞体对快速适应机械刺激的敏感性 电流和致敏反应芥子油，这表明Piezo 2和TRPA 1通道活动可能是 增强抑制TRPA 1可增强FD患者的行为机械超敏反应。传入纤维也 显示出明显的自发活动，这可能是持续疼痛的基础。这一现象的科学假设 提示FD患者DRG感觉神经元功能紊乱，鞘糖脂升高， 敏化感觉神经元中的Piezo 2和TRPA 1通道，导致机械超敏反应， 持续的疼痛。该提案将定义介导法布里病疼痛的机制，自上而下 方法的目的是：1）定义刺激诱发的、持续的和危机诱发的疼痛行为随时间的变化 在雄性和雌性Fabry大鼠中，2）确定DRG是否是产生和维持 机械性和持续性疼痛，以及3）询问Piezo 2和/或TRPA 1离子通道是否介导了 在Fabry大鼠中观察到机械致敏。除了确定FD的疼痛机制外， 具体而言，这些研究将通过确定可以促进 理解触觉异常性疼痛和其他类型的自发性疼痛的机制 神经性疾病，并揭示脂质在机械转导机制中的新作用， 躯体感觉系统

Project Summary The central goal of this project is to identify the cellular mechanisms that underlie the mechanical hypersensitivity and pain in Fabry Disease (FD), and thereby identify novel targets for improved pain treatment. FD is the most common lysosomal storage disease. It results from a deficiency of the lysosomal enzyme α- galactosidase A (α-Gal A) that leads to the accumulation of glycosphingolipids within the lysosomes of cells including dorsal root ganglia (DRG) neurons. Small fiber neuropathy is a hallmark of FD. Neuropathic-like pain begins around age 5, worsens with age, and affects 60-80% of all (male and female) patients. The pain is described as episodic “pain crises” triggered by fever, exercise, fatigue or stress, and chronic “permanent pain.” We created a transgenic rat model of FD using CRISPR/Cas9 to delete the gene encoding α-Gal A. Fabry rats closely recapitulate many phenotypes observed in patients, including elevated serum levels of α- galactosyl glycosphingolipids, spontaneous and mechanically-evoked pain behavior, pronounced lipid inclusions and aberrant accumulation of α-galactosyl glycosphingolipids in small-diameter DRG neurons and severe hearing loss. Sensory neurons somata from Fabry rats have sensitized rapidly adapting mechanical currents and sensitized responses to mustard oil, suggesting that Piezo2 and TRPA1 channel activities may be enhanced. Inhibition of TRPA1 alleviates the behavioral mechanical hypersensitivity in FD. Afferent fibers also show clear spontaneous activity, which may underlie the ongoing pain. The Scientific Premise of this proposal is that DRG sensory neurons in FD are dysfunctional and that the glycosphingolipids elevated in FD sensitize Piezo2 and TRPA1 channels in sensory neurons, resulting in the mechanical hypersensitivity and ongoing pain. This proposal will define the mechanisms that mediate Fabry disease pain in a top-down approach through Aims that 1) define the stimulus evoked, ongoing, and crisis-evoked pain behavior over time in male and female Fabry rats, 2) determine if the DRG is a key site for the generation and maintenance of mechanical and ongoing pain, and 3) interrogate whether Piezo2 and/or TRPA1 ion channels mediate the mechanical sensitization observed in the Fabry rat. In addition to identifying pain mechanisms that are FD- specific, these studies will have a broader impact by identifying mechanisms that could advance the understanding of mechanisms that underlie tactile allodynia and spontaneous pain in other types of neuropathic disorders and uncover novel roles for lipids in mechanotransduction mechanisms in somatosensory systems.