Sodium Channels and Neuroprotection in Neuroinflammatory Disorders

神经炎症性疾病中的钠通道和神经保护

• 批准号: 8840065
• 负责人: Stephen Waxman
• 金额: --
• 依托单位: VA CONNECTICUT HEALTHCARE SYSTEM
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-10-01 至 2014-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8840065
• 关键词: Acute; Anti-Inflammatory Agents; Anti-inflammatory; Astrocytes; Attenuated; Axon; Axotomy; Back; Carbamazepine; Cells; Clinical Research; Demyelinations; Disease; Exhibits; Experimental Autoimmune Encephalomyelitis; Health; Human; Immune; In Vitro; Inflammation; Inflammatory; Inflammatory Response; Ion Channel; Knock-out; Laboratories; Lead; Lesion; MAPK14 gene; MAPK8 gene; Mediating; Methods; Microglia; Mitogen-Activated Protein Kinases; Multiple Sclerosis; Multiple Sclerosis Lesions; Mus; Nerve Degeneration; Neuroprotective Agents; Phagocytosis; Phenytoin; Phosphoric Monoester Hydrolases; Play; Property; Regulation; Role; Signal Pathway; Site; Sodium Channel; Sodium Channel Blockers; Spinal cord injury; Testing; Tissues; Up-Regulation; Veterans; Withdrawal; Work; axonal degeneration; channel blockers; disability; injured; interest; knock-down; macrophage; migration; mortality; neuroinflammation; neuroprotection; restoration; small hairpin RNA; transmission process; voltage

DESCRIPTION (provided by applicant): My laboratory is interested in neuroprotective approaches in neuroinflammatory disorders, including MS and SCI, where inflammation has been shown to occur within the injured spinal cord. In addition to studies that target axonal ion channels for axonal neuroprotection in disorders such as MS, we are interested in the contribution of voltage-gated Na channels within glial and immune cells to their functions in neuroinflammatory diseases, and in the effects of Na channel block in these cells. In this proposal, we focus on the following Specific Aims: I. Sodium Channel Blockers and Neuroprotection in Neuroinflammatory Disorders We have demonstrated that Na channel blockers have anti-inflammatory and neuroprotective effects in mice with EAE, but we observed acute worsening following Na channel blocker withdrawal. Several clinical studies of Na channel blockers in MS are ongoing. We will now determine whether exacerbation of EAE is unique to C57/BL6 mice and whether withdrawal of other Na channel blockers exacerbates EAE. II. Sodium Channel Nav1.5 and Functions of Astrocytes in Neuroinflammation We have demonstrated that human astrocytes express Na channels and that reactive astrocytes exhibit robust upregulation of Nav1.5 at the borders of, and within, MS lesions. We will now determine the contribution of Na channels to effector roles of astrocytes in neuroinflammatory disorders, using methods that include shRNA knock-down and Cre/lox knockouts. III. Sodium Channels and Functions of Microglia We have shown that Nav1.5 and Nav1.6 are present and functional within microglia / macrophages, and that Na channel blockade attenuates their migration and phagocytosis. However, the effects of Na channel blockade on other microglial/macrophage functions is less well understood, and there is a need to understand signaling pathways that control microglial/macrophage function. We have shown that ERK, p38 and JNK regulate migration of microglia, and that levels of phosphorylated ERK are attenuated in microglia following Na channel blockade. Recently, it was shown that induction of mitogen-activated protein kinase phosphatase (MPK), which dephosphorylates ERK, reduces migration of microglia. We will now examine the contribution of Na channels to multiple functions and signaling pathways of activated microglia. Injured axons in the CNS can undergo substantial retraction (die-back) from the initial site of axotomy. This can interfere with functional transmission along more proximal, initially uninjured axonal branches; or may lead to degeneration of sustaining collaterals and neuronal degeneration. We and others have demonstrated that microglia/macrophages can engulf transected axonal ovoids, but details of the role of microglia in axonal degeneration are not yet understood. We will therefore study the role of microglia/macrophages in axonal degeneration. IV. Studies in Human MS Tissue Building upon our prior studies on human MS tissue, we will extrapolate from our in vitro studies and studies with EAE to test the hypotheses in human MS lesions that astrocytes at the active edge of MS lesions show different properties in terms of Na channel expression compared to astrocytes in central parts of these lesions; that microglia/macrophages at the active border of MS lesions show different properties in terms of Na channel expression compared to microglia/macrophages in central parts of these lesions; and that microglia/ macrophages mediate axonal die-back in MS.

描述（由申请人提供）： 我的实验室对包括MS和SCI在内的神经炎症性疾病中的神经保护方法感兴趣，其中已显示在受伤的脊髓内发生炎症。除了针对MS等疾病中轴突神经保护剂靶向轴突离子通道的研究外，我们对胶质和免疫细胞内电源门控的Na通道的贡献感兴趣在这些细胞中。在该提案中，我们关注以下特定目的：I。钠通道阻滞剂和神经炎症性疾病中的神经保护因素，我们已经证明NA通道阻滞剂在EAE中具有抗炎和神经保护作用，但我们观察到Na通道阻滞剂急性变速提取。 MS中NA通道阻滞剂的几项临床研究正在进行中。现在，我们将确定EAE的加剧是否是C57/BL6小鼠独有的，以及其他NA通道阻滞剂的撤回是否加剧了EAE。 ii。钠通道NAV1.5和星形胶质细胞在神经炎症中的功能，我们已经证明人星形细胞表达Na通道，而反应性星形胶质细胞表现出强大的NAV1.5上调在NAV1.5的边界和内部，MS MS病变。现在，我们将使用包括SHRNA敲除和CRE/LOX敲除的方法来确定NA通道对星形胶质细胞在神经炎症性疾病中的效应子作用的贡献。 iii。小胶质细胞的钠通道和功能我们已经表明，NAV1.5和NAV1.6在小胶质细胞 /巨噬细胞中存在并功能性，并且NA通道的阻滞减弱了其迁移和吞噬作用。但是，NA通道阻断对其他小胶质细胞/巨噬细胞功能的影响知之甚少，并且需要了解控制小胶质细胞/巨噬细胞功能的信号通路。我们已经表明，ERK，p38和JNK调节小胶质细胞的迁移，并且在Na通道阻滞后，小胶质细胞中的磷酸化ERK水平会减弱。最近，结果表明，有丝分裂原激活的蛋白激酶磷酸酶（MPK）的诱导诱导，该蛋白激酶磷酸酶（MPK）降低了ERK，减少了小胶质细胞的迁移。现在，我们将研究NA通道对活化小胶质细胞的多个功能和信号通路的贡献。中枢神经系统中的受伤轴突可以从轴切开术的初始部位进行大量缩回（倒倒）。这会干扰沿更近端，最初未受伤的轴突分支的功能传播。或可能导致持续侧支和神经元变性的变性。我们和其他人已经证明，小胶质细胞/巨噬细胞可以吞噬轴突卵形，但尚不清楚小胶质细胞在轴突变性中的作用的细节。因此，我们将研究小胶质细胞/巨噬细胞在轴突变性中的作用。 iv。在人类MS组织中的研究基于我们先前对人类组织组织的研究，我们将从我们的体外研究和对EAE进行研究中推断出人类MS病变中的假设，这些假设在MS病变的活动边缘处的星形胶质细胞在MS病变的活性边缘显示出不同的特性，这些特性在与这些病变中央部分的星形胶质细胞相比，NA通道表达；与这些病变的中心部分的小胶质细胞/巨噬细胞相比，MS病变活性边界处的小胶质细胞/巨噬细胞在Na通道表达方面显示出不同的特性。小胶质细胞/巨噬细胞介导MS中的轴突倒态。