GSK3: immunoregulator in experimental autoimmune encephalomyelitis (EAE)

描述(申请人提供)：多发性硬化症(MS)是一种中枢神经系统(CNS)的自身免疫性炎症性疾病，以免疫介导的中枢神经系统脱髓鞘和神经变性为特征，目前尚无足够的治疗干预措施。这种疾病的特点是大脑中驻留细胞的局部炎症和外周白细胞的渗透。MS最初被认为是一种T细胞介导的自身免疫性疾病，至少在发病初期，对几种髓鞘来源的抗原具有自身反应性。与这种疾病相关的其他细胞类型包括树突状细胞、巨噬细胞和小胶质细胞。糖原合成酶-3(GSK3)是多种细胞功能的关键调节因子，我们和其他人现在报道它是炎症的主要调节因子。GSK3的失调与几种与炎症相关的神经退行性疾病有关，如阿尔茨海默病、帕金森病和肌萎缩侧索硬化症。我们发现，用GSK3抑制剂锂预处理的小鼠完全免受实验性自身免疫性脑脊髓炎(EAE)的发展，实验性自身免疫性脑脊髓炎(EAE)是多发性硬化症的小鼠模型，临床疾病发生后的锂治疗可以改善EAE并抑制复发。相反，在表达固有活性GSK3的敲击小鼠中，EAE发展得更快、更严重。这些数据提供了强有力的证据表明GSK3在EAE中是促炎的，然而GSK3调节中枢神经系统炎症的机制尚未解决。我们发现，锂治疗的小鼠从EAE中恢复与小胶质细胞激活减少和脱髓鞘减少有关。我们还证明，在体内用GSK3抑制剂锂治疗小鼠，剂量与人类相同的剂量，与未治疗的免疫小鼠相比，锂治疗组小鼠的脾细胞中抗原特异性T细胞增殖和促炎细胞因子受到抑制。基于这些数据，我们的中心假设是GSK3促进了EAE的促炎性级联反应。为了检验这一假说，我们将：1)扩大和跟进我们的初步发现，通过检查在体内通过药理学和遗传学方法调节GSK3对急性和复发/缓解型EAE的发生和进展的后果；2)进行体外研究，以解决锂介导的保护机制，以检验锂在小鼠体内衰减的主要靶点是树突状细胞和小胶质细胞的假说。我们提出的研究将为GSK3治疗多发性硬化症和其他神经炎症性疾病奠定治疗靶向的框架。由于锂已经是FDA批准的治疗精神障碍的药物，这项提议的结果可以导致对人类患者的快速评估。此外，随着更具特异性的GSK3抑制剂正在开发中，这项研究很可能成为它们用于治疗MS和其他带有炎症成分的神经退行性疾病的基础。公共卫生相关性：本申请中提出的研究将更好地了解导致实验性自身免疫性脑脊髓炎以及多发性硬化症和其他中枢神经系统炎症性疾病的神经损害的炎症事件。这个项目与公共卫生非常相关，因为炎症不仅与多发性硬化症有关，还与其他几种神经退行性疾病和精神疾病有关。GSK3酶被确认为大脑炎症过程的中央调节因子，这将为开发更具针对性的治疗多发性硬化症和其他涉及炎症成分的神经系统疾病的靶向疗法打开可能性。

DESCRIPTION (provided by applicant): Multiple sclerosis (MS) is an autoimmune inflammatory disease of the central nervous system (CNS), characterized by an immune-mediated demyelination and neurodegeneration of the CNS, for which there is no adequate therapeutic intervention. The disease is characterized by both local inflammation from resident cells in the brain and by the infiltration of leucocytes from the periphery. MS is primarily considered a T cell-mediated autoimmune disease, at least in the initiation phase, with self reactivity against several myelin-derived antigens. Other cell types involved in the disease are dendritic cells, macrophages, and microglia. The enzyme glycogen synthase kinase-3 (GSK3) is a critical regulator of a variety of cellular functions, and we and others now report that it is a major regulator of inflammation. Dysregulation of GSK3 is associated with several neurodegenerative disorders associated with inflammation, such as Alzheimer's disease, Parkinson's disease, and Amyotrophic Lateral Sclerosis. We found that mice pretreated with the GSK3 inhibitor lithium are completely protected from development of experimental autoimmune encephalomyelitis (EAE), a mouse model of MS, and that lithium treatment after onset of clinical disease ameliorates EAE and inhibits relapses. Conversely, in knockin mice expressing constitutively active GSK3, EAE developed more rapidly and was more severe. These data provides strong evidence that GSK3 is proinflammatory in EAE, however the mechanism by which GSK3 regulates inflammation in the CNS is unresolved. We found that the recovery from EAE in lithium treated mice is associated with reduced microglia activation, and decreased demyelination. We also demonstrated that treatment of mice in vivo with the GSK3 inhibitor lithium, at doses that parallel doses used in humans, inhibited antigen-specific T cell proliferation and proinflammatory cytokine from splenocytes of lithium-treated compared to untreated immunized mice. Based on these data our central hypothesis is that GSK3 promotes proinflammatory cascades in EAE. To test this hypothesis, we will: 1) expand and follow up our initial findings by examining the consequences of modulating GSK3 in vivo by pharmacological and genetic approaches on the development and progression of acute and relapsing/remitting EAE; 2) perform ex-vivo studies to address the mechanism of lithium-mediated protection to test the hypothesis that the major target of lithium attenuation of EAE in mice are dendritic cells and microglia. Our proposed studies will set the framework for therapeutic targeting of GSK3 for treatment of MS and other neuroinflammatory diseases. Since lithium is already a drug approved by FDA for treatment of psychiatric disorders, the outcome of this proposal can lead to rapid evaluations in human patients. Furthermore, with the availability of more specific GSK3 inhibitors that are being developed, this study is likely to be the basis for their use in the treatment of MS, and other neurodegenerative diseases with inflammatory components. PUBLIC HEALTH RELEVANCE: The research proposed in this application will provide better understanding of the inflammatory events that lead to neurological damage in experimental autoimmune encephalomyelitis, and by extension in multiple sclerosis and other inflammatory diseases of the central nervous system. This project is very relevant to public health because inflammation is linked not only to multiple sclerosis, but also to several other neurodegenerative, and psychiatric diseases. The identification of the enzyme GSK3 as a central regulator of the inflammatory processes in the brain will open a possibility for developing more specific targeted therapy for treatment of multiple sclerosis and other neurological diseases that involve inflammatory components.