Cytokines in Glial Cells and EAE Brain

描述(申请人提供)：多发性硬化症(MS)，一种炎症性脱髓鞘疾病，缺乏有效的治疗，因为目前针对免疫抑制的MS药物对中枢神经系统(CNS)疾病继续发展的益处有限(如果有的话)。本研究旨在研究靶向Rho家族GTP酶(RFGs)的药物在EAE/MS中枢神经系统中诱导内源性髓鞘修复机制的可能性。本实验室等人的先前研究表明，在实验性自身免疫性脑脊髓炎(EAE)中，他汀类药物对RFGs的调节提供了免疫调节和血脑屏障保护活性。我们最近的研究为RFGs介导的神经保护机制提供了证据，其表现为脱髓鞘减少(髓鞘蛋白和脂类的丢失)和OL前体细胞的丢失。此外，混合胶质细胞培养的体外研究证明，RFGs介导的机制也可能提供早幼粒细胞效应，这一点可以通过增强少突胶质细胞(OL)前体细胞的存活和分化来证明。重要的是，他汀类药物的这些作用归因于细胞内类异戊二烯的特异性消耗，而不是细胞或中枢神经系统中的胆固醇水平。此外，观察到EAE患者中枢神经系统中PPAR水平的降低以及他汀类药物对其的正常化和激活，提示他汀类RFGs介导的机制可能调节PPAR的细胞内稳态。基于这一信息，我们推测他汀类药物对RFGs的调节可能通过调节OL祖细胞中的PPAR活性来促进其在EAE动物中枢神经系统中分化为重新髓鞘的OL。为了验证这一假说，我们建议进行以下研究。具体目的1：在体外细胞培养系统中，探讨RFGs介导的PPAR激活对OL祖细胞存活和分化的调控机制。具体目的2：评价RFGs诱导的PPAR活性在EAE炎性脱髓鞘模型中诱导髓鞘修复的意义。本研究的创新之处在于发现诱导髓鞘修复的新的治疗靶点，以改善对MS等神经退行性疾病的治疗和管理。在炎性脱髓鞘模型中以神经细胞机制为靶向治疗本质上是一种创新的方法。 公共卫生相关性：多发性硬化症是一种自身免疫性炎症性脱髓鞘疾病，仅在美国就影响大约40万人，全球超过200万人。尽管目前的治疗方法是针对免疫反应，但疾病的进展往往会导致神经变性，从而导致反映中枢神经系统损伤的身体残疾。因此，缺乏有效的治疗多发性硬化症的方法是治疗中枢神经系统疾病的一大缺口。除了抗炎和免疫调节特性外，最近观察到的他汀类药物的神经保护活性通过靶向内源性前体细胞确定了其髓鞘修复机制的新方面。这些研究具有创新性，因为它们将提高我们对药物增强中枢神经系统内源性细胞治疗多发性硬化中枢神经系统疾病(髓鞘修复)潜力的机制的理解。这些研究将确定诱导多发性硬化症髓鞘修复的治疗靶点，这些发现应该适用于其他相关的神经退行性疾病。

DESCRIPTION (provided by applicant): Multiple Sclerosis (MS), an inflammatory demyelinating disease, lacks effective treatment because the current MS drugs targeting immunosuppression provide limited, if any, benefit to the central nervous system (CNS) disease where it continues to progress. This proposal is designed to investigate the potential of drugs targeting the Rho family GTPases (RFGs) for induction of endogenous myelin repair mechanisms in the CNS of EAE/MS. Previous studies from our laboratory and others have demonstrated that isoprenoids mediated regulation of RFGs with statins provides immunomodulatory and blood-brain-barrier protection activities in experimental autoimmune encephalomyelitis (EAE), an animal model of MS. Our recent studies provide evidence for involvement of RFGs mediated mechanisms in neuroprotection as revealed by reduced demyelination (loss of both myelin proteins and lipids) and loss of OL-progenitors in EAE. Moreover, in vitro studies with mixed glial cultures document that RFGs mediated mechanisms may also potentially provide promyelinating effects as evidenced by enhanced survival and differentiation of oligodendrocyte (OL)-progenitors. Importantly, these effects of statins were attributed to be the specific depletion of intracellular isoprenoids rather than the level of cholesterol in the cells or CNS. Moreover, the observed reduced levels of peroxisome proliferator activated receptors (PPARs) in the CNS of EAE and their normalization and activation by statin indicates that statin-RFGs mediated mechanisms may regulate the cellular homeostasis of PPARs. Based on this information, we hypothesize that statin mediated regulation of RFGs may modulate PPARs activities in OL-progenitors to promote their differentiation into remyelinating OLs in the CNS of EAE animals. The following studies are proposed to test this hypothesis. Specific aim 1: To investigate the RFGs mediated regulatory mechanisms for PPARs activation for the survival and differentiation of OL-progenitors in vitro cell culture systems. Specific aim 2: To evaluate the significance of RFGs induced PPARs activities in the induction of myelin repair in the inflammatory demyelinating model of EAE. The novelty of the study is to identify new therapeutic targets for induction of myelin repair for improved treatment and management of neurodegenerative diseases such as MS. Therapeutic targeting of neural cell mechanisms in inflammatory demyelinating model is essentially an innovative approach. PUBLIC HEALTH RELEVANCE: MS an autoimmune inflammatory demyelinating disease, affects approximately 400,000 individuals in US only and over 2.0 million individuals worldwide. In spite of the current therapeutics targeting immune response, the disease often progresses leading to neurodegeneration and thus physical disability reflecting the CNS injury. Therefore, the lack of effective treatments for MS represents a significant gap for treating the CNS disease. In addition to the anti-inflammatory and immunomodulatory properties the recently observed neuroprotective activities of statins identify novel aspect of their mechanisms for myelin repair by targeting the endogenous precursor cell. The proposed studies are innovative as they will improve our understanding of mechanisms for pharmacological enhancement of the potential of CNS endogenous cells to treat CNS disease (myelin repair) in MS. These studies will identify therapeutic targets for induction of myelin repair in MS and these findings should be applicable to other related neurodegenerative diseases.