Pain Mechanisms in Fabry Disease

项目摘要 这个项目的中心目标是确定机械的细胞机制。 此外，我们还将研究Fabry病(FD)中的过敏性和疼痛，从而确定改进疼痛治疗的新靶点。 FD是最常见的溶酶体蓄积性疾病。它是由于溶酶体酶α缺乏所致。 半乳糖苷酶A(α-GalA)，导致糖鞘糖脂在细胞溶酶体内积累 包括背根神经节(DRG)神经元。小纤维神经病是FD的一个标志。神经病理性疼痛 开始于5岁左右，随着年龄的增长而恶化，影响到所有患者(男性和女性)的60%-80%。痛苦的是 被描述为由发烧、运动、疲劳或压力引发的间歇性“疼痛危机”，以及慢性“永久性” 很痛苦。“我们使用CRISPR/CAS9建立了一个转基因的FD大鼠模型，以删除编码α-GalA的基因。 法布里大鼠紧密地概括了在患者中观察到的许多表型，包括血清α-1水平升高。 半乳糖基鞘糖脂，自发和机械诱发的疼痛行为，明显的脂质 α-半乳糖基鞘糖脂在小直径背根神经节神经元内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迅速敏化适应机械 电流和对芥子油的敏化反应，提示Piezo2和TRPA1通道活动可能是 增强版。抑制TRPA1可减轻FD大鼠的行为机械超敏反应。传入纤维也 表现出明显的自发活动，这可能是持续疼痛的原因。这其中的科学前提 有观点认为，FD的DRG感觉神经元功能障碍，而FD的神经鞘糖脂升高 敏化感觉神经元上的Piezo2和TRPA1通道，导致机械超敏和 持续的疼痛。该提案将定义自上而下调节Fabry病疼痛的机制 通过目标1)定义随时间推移的刺激引起的、持续的和危机引起的疼痛行为 在雄性和雌性Fabry大鼠中，2)确定背根神经节是否是产生和维持 3)询问Piezo2和/或TRPA1离子通道是否介导了 在法布里大鼠体内观察到机械敏化。除了确定FD的疼痛机制外- 具体地说，这些研究将通过确定可能促进 对其他类型的触觉异常和自发性疼痛的机制的理解 神经病变和发现脂类在机械转导机制中的新作用 体感系统。

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.