Lymphocyte Functions in the Injured Spinal Cord

描述（由申请人提供）：脊髓损伤（SCI）激活免疫细胞，导致CNS组织损伤。迄今为止，这一领域的大多数研究都集中在巨噬细胞和T细胞的损伤作用上。然而，结合CNS蛋白的抗体在SCI患者的血清和脑脊液中积累，这表明活化的B细胞可能有助于创伤后炎症损伤。在过去的五年中，我们已经表明，SCI触发B细胞活化和自身抗体的合成。重要的是，没有B细胞的小鼠在SCI后具有较小的损伤和改善的恢复。在这次更新申请中，我们将测试SCI后产生的抗体加剧神经元和神经胶质病理从而限制功能恢复的假设。提出了三个具体目标。在Aim 1中，我们将使用蛋白质组学来揭示SCI后激活B细胞的蛋白质的身份。在目的2中，我们将研究在损伤后不同时间从SCI小鼠获得的纯化抗体的生物学效应。这将通过将纯化的抗体注射到脊髓的特定区域，然后对脊髓功能进行行为和电生理分析来实现。将使用标准免疫组织化学技术记录抗体介导的神经元/神经胶质细胞存活、轴突病理学和/或脱髓鞘变化。同样在目标2中，我们将评估负责脊柱内抗体注射引起的任何有害作用的机制。这将通过将抗体注射到经过遗传修饰的小鼠中来实现，使得它们缺乏已知介导抗体作用的关键蛋白质。在目标3中，我们将确定两个关键的B细胞存活因子是否对SCI后B细胞的慢性椎管内活动负责。具体来说，我们将记录SCI后BAFF和APRIL的时空诱导模式和来源。为了确定这些生长因子是否可以被操纵到干B细胞和SCI后抗体介导的病理学，我们将在损伤部位注入诱饵受体，其将阻断BAFF和APRIL信号传导。总的来说，本研究中的实验将提供关于抗体产生B细胞对SCI引起的组织损伤的贡献的新信息。此外，这些研究将可能揭示治疗SCI的新的治疗靶点。公共卫生相关性这项提案将确定激活B细胞的蛋白质的身份，导致它们在脊髓损伤（SCI）后产生致病性自身抗体。此外，负责脊髓中自身抗体介导的损伤的机制将被确定，并且将开发阻断SCI介导的B细胞活化的新策略。这些研究的数据将用于开发治疗人类SCI的新临床疗法。

DESCRIPTION (provided by applicant): Spinal cord injury (SCI) activates immune cells that cause tissue damage in the CNS. To date, most studies in this area have focused on the injurious effects of macrophages and T cells. However, antibodies that bind CNS proteins accumulate in sera and cerebrospinal fluid of people with SCI, suggesting that activated B cells may contribute to post-traumatic inflammatory damage. During the last five years, we have shown that SCI triggers B cell activation and autoantibody synthesis. Importantly, mice without B cells have smaller lesions and improved recovery after SCI. In this renewal application, we will test the hypothesis that antibodies produced after SCI exacerbate neuron and glial pathology thereby limiting functional recovery. Three specific aims are proposed. In Aim1, we will use proteomics to reveal the identities of proteins that activate B cells after SCI. In Aim 2, we will investigate the biological effects of purified antibodies obtained from SCI mice at different times after injury. This will be accomplished by injecting purified antibodies into specific regions of the spinal cord followed by behavioral and electrophysiological analysis of spinal cord function. Antibody-mediated changes in neuron/glial survival, axon pathology and/or demyelination will be documented using standard immunohistochemical techniques. Also in Aim 2, we will evaluate the mechanisms responsible for any detrimental effects caused by intraspinal antibody injection. This will be accomplished by injecting antibodies into mice that have been genetically modified such that they lack key proteins that known to mediate the effects of antibodies. In Aim 3, we will determine if two key B cell survival factors are responsible for the chronic intraspinal activity of B cells after SCI. Specifically, we will document spatiotemporal induction patterns and sources of BAFF and APRIL after SCI. To determine if these growth factors can be manipulated to stem B cell and antibody-mediated pathology after SCI, we will infuse the injury site with decoy receptors that will block BAFF and APRIL signaling. Collectively, the experiments in this proposal will provide novel information about the contributions of antibody-producing B cells to the tissue damage caused by SCI. Moreover, these studies will likely reveal novel therapeutic targets for treating SCI. PUBLIC HEALTH RELEVANCE This proposal will determine the identities of proteins that activate B cells, causing them to produce pathogenic autoantibodies after spinal cord injury (SCI). Moreover, the mechanisms responsible for autoantibody-mediated injury in the spinal cord will be determined and new strategies to block SCI-mediated B cell activation will be developed. Data from these studies will be used to develop novel clinical therapies to treat SCI in humans.