GSK3: immunoregulator in experimental autoimmune encephalomyelitis (EAE)

描述（由申请人提供）：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，其特征是免疫介导的脱髓鞘和中枢神经系统的神经退行性变，没有足够的治疗干预。这种疾病的特点是来自脑内驻留细胞的局部炎症和来自外周的白细胞浸润。MS主要被认为是一种T细胞介导的自身免疫性疾病，至少在起始阶段，对几种髓鞘源性抗原具有自身反应性。其他涉及该疾病的细胞类型包括树突状细胞、巨噬细胞和小胶质细胞。糖原合成酶激酶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，这是一种多发性硬化症小鼠模型，并且在临床疾病发作后使用锂治疗可以改善EAE并抑制复发。相反，在表达组成型活性GSK3的敲入小鼠中，EAE发展更快，更严重。这些数据为GSK3在EAE中具有促炎作用提供了强有力的证据，然而，GSK3调节中枢神经系统炎症的机制尚不清楚。我们发现锂处理小鼠EAE的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，在小鼠体内用GSK3抑制剂锂治疗，剂量与在人体内使用的剂量相当，与未治疗的免疫小鼠相比，锂治疗小鼠脾细胞的抗原特异性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EAE的促炎级联反应。为了验证这一假设，我们将：1)通过药理学和遗传学方法研究体内调节GSK3对急性和复发/缓解型EAE的发展和进展的影响，扩大和跟进我们的初步发现；2)开展离体研究，探讨锂介导的保护机制，验证锂对小鼠EAE的衰减主要作用靶点为树突状细胞和小胶质细胞的假设。我们提出的研究将为GSK3靶向治疗多发性硬化症和其他神经炎性疾病建立框架。由于锂已经被FDA批准用于治疗精神疾病，因此该提案的结果可以在人类患者中进行快速评估。此外，随着更多特异性GSK3抑制剂的开发，该研究可能成为其用于治疗多发性硬化症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的神经损伤的炎症事件，进而扩展到多发性硬化症和其他中枢神经系统炎症性疾病。这个项目与公共卫生密切相关，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酶作为大脑炎症过程的中枢调节因子的鉴定，将为开发更具体的靶向治疗多发性硬化症和其他涉及炎症成分的神经系统疾病提供可能性。

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.