Pathogenesis of anti-ganglioside antibody-mediated neuropathies

描述(申请人提供)：抗神经节苷脂抗体(Abs)是被称为格林-巴利综合征(GBS)的免疫性神经病中最常见的自身免疫反应。具有GM1和GD1a特异性的ABS与GBS的运动性轴突变异有关，在轴索和脱髓鞘形式中恢复不良。一个令人费解的临床发现是，具有相同特异性的抗神经节苷脂抗体的患者在临床表型和结果上存在差异。我们的总体目标是研究抗神经节苷脂抗体对完整和受损神经纤维的潜在病理生物学作用机制。我们的初步研究表明：a)抗神经节苷脂抗体导致神经、Ranvier结节和运动神经末梢的特定区域功能障碍；b)抗神经节苷脂抗体在动物模型中抑制受损神经纤维的再生；c)在两种动物模型中，高亲和力的单抗对完整和损伤的神经纤维具有病理生物学效应。根据这些结果，我们假设抗神经节苷脂抗体：1)通过改变Ranvier结节和运动神经末梢的离子通道和/或胞吐机制的蛋白质而导致可逆性神经功能障碍；2)抑制神经再生，这是抗神经节苷脂抗体治疗的GBS患者恢复不良的机制之一；3)抗体亲和力决定神经损伤的程度和类型以及临床表型。此次更新将通过以下具体目标来检验这些假说：目标1将在神经内注射模型中检查抗神经节苷脂抗体对完整的Ranvier结节的影响；目标2将通过宏观膜片钳研究这些抗体如何影响神经肌肉传递；在目标3中，这些抗体对神经再生的影响将在坐骨神经挤压和神经移植模型中被研究；以及目标4将通过在动物和组织培养神经损伤模型中通过关联抗体亲和力(在固相分析中确定)和致病性来评估抗体亲和力在神经病理损伤中的作用。这些研究将提供抗体介导的轴突损伤的详细发病机制，这将有助于开发治疗自身免疫性疾病的方法，如免疫性神经病和多发性硬化症，在这些疾病中，轴突损伤是康复差的核心。公开信息声明：这项转译研究项目旨在研究GBS轴突损伤的机制。这些研究将有助于开发治疗策略，以防止轴突变性和增强轴突再生的自身免疫性神经病。

DESCRIPTION (provided by applicant): Anti-ganglioside antibodies (Abs) are the most frequently recognized autoimmune responses in immune neuropathies termed Guillain-Barre syndrome (GBS). Abs with GM1 and GD1a specificity are associated with the motor axonal variant of GBS and poor recovery in both axonal and demyelinating forms of the disease. A puzzling clinical finding is that patients with anti-ganglioside Abs of same specificities have variations in clinical phenotype and outcome. Our overall goal is to study mechanisms underlying pathobiologic effects of anti-ganglioside Abs on intact and injured nerve fibers. Our preliminary studies show that: a) anti-ganglioside Abs induce dysfunction at specialized regions of the nerves, nodes of Ranvier and motor nerve terminals; b) an anti-ganglioside Ab inhibits regeneration of injured nerve fibers in an animal model; and C) a monoclonal Ab with high affinity has pathobiologic effects on intact and injured nerve fibers in two animal models. From these results we hypothesize that anti-ganglioside Abs: 1) induce reversible nerve dysfunction by altering ion channels and/or proteins of exocytic machinery at nodes of Ranvier and motor nerve terminals; 2) inhibit nerve regeneration, which is one mechanism of poor recovery in GBS patients with anti-ganglioside Abs; and 3) Ab affinity determines extent and type of nerve injury and clinical phenotype. This renewal will test these hypotheses by the following specific aims: Aim 1 will examine the effects of anti-ganglioside Abs on intact nodes of Ranvier in an intraneural injection model; how these Abs affect neuromuscular transmission will be investigated by macro-patch-clamp studies in Aim 2; in Aim 3, effects of these Abs on nerve regeneration will be studied in sciatic nerve crush and nerve transplant models; and Aim 4 will evaluate the role of Ab affinity in neuropathic injury by correlating Ab affinity (as determined in solid phase assays) and pathogenicity in animal and tissue culture models of nerve injury. These studies will provide detailed pathogenesis of Ab-mediated axon injury, which will help in developing therapies for autoimmune conditions like immune neuropathies and multiple sclerosis where axonal damage is central to poor recovery. Public information statement: This translational research project seeks to examine mechanisms of axonal injury in GBS. These studies will help develop treatment strategies to prevent axonal degeneration and enhance axonal regeneration in autoimmune neuropathies.