Harnessing microglia towards repair vs. damage: Does p38 MAPK hold the reins?

描述(由申请人提供)： 阿尔茨海默病(AD)的一个主要病理成分是脑部炎症。小胶质细胞是“大脑的巨噬细胞”，它的激活被认为是阿尔茨海默病发生的原因，也是神经元损伤的原因之一。对外周巨噬细胞的研究已经确定巨噬细胞存在多种不同的激活状态，最近的研究证实了小胶质细胞的这些发现。巨噬细胞/小胶质细胞可以广义地定义为经典激活或交替激活。经典激活的巨噬细胞的典型特征是释放促炎症细胞因子(如IL-12、肿瘤坏死因子-1)和活性氧和氮物种，它们是已知引起神经元损伤的炎症反应的组成部分。然而，并不是所有形式的小胶质细胞激活都是有害的。某些形式的小胶质细胞激活是有益的，例如导致淀粉样β蛋白(A2)的去除或清除的替代激活反应。这一提议将检验这样一种假设，即p381 MAP激酶信号级联导致有害形式的小胶质细胞激活，并且阻断p381通路将减少激活的小胶质细胞的有害反应而不影响有益反应。目的1验证在AD相关转基因小鼠模型(Tg6799小鼠)发病早期，小胶质细胞中存在p381MAPK信号级联激活的假说。目的2将使用一种新的、脑穿透的、小分子的p381抑制剂来测试抑制p381活性将减缓Tg6799小鼠病理的假设。这一目标将提供使用药理学工具、神经退行性疾病的转基因模型和治疗靶点验证方面的培训。目的3将评估小胶质细胞中p381相对于其他类型神经细胞在A2造成的损伤中的相对贡献。为了测试这一目的，我们将使用A2注射AD相关模型，在小鼠中仅在小胶质细胞中缺失p381基因。这一目标将提供使用cre/lox系统的条件性基因敲除小鼠模型的培训，以及小鼠的立体定位手术。该项目的成功完成将提供对关键调节蛋白p381如何参与中枢神经系统病理生理学机制和干预反应的机械性洞察，并将为针对这一重要蛋白激酶的后续中枢神经系统治疗开发活动奠定基础。职业发展计划已经正式确定，其中包括参加正式课堂和专业讲习班，定期在实验室和研究小组一级介绍拟议的研究计划和结果，以研讨会形式介绍独立研究成果，参加国家和国际科学会议，编写研究提案和出版物，以及发展更多促进职业发展的技能。一位经验丰富的导师，丰富的科学环境，以及有组织的教育和培训计划，将确保申请者拥有最佳的科学成长、职业发展和发展为独立学术研究人员的机会。 公共卫生相关性： 神经炎症越来越被认为是许多神经退行性疾病的病理因素，例如阿尔茨海默病，这是一种没有有效治疗或治愈的破坏性衰老疾病。该项目的成功完成将提供对关键调控蛋白p381MAPK如何参与疾病相关应激源引起的脑促炎反应和中枢神经系统功能障碍的机械性洞察。此外，研究结果还将揭示小胶质细胞p381MAPK在疾病相关病理反应中的相对重要性。从长远来看，拟议研究产生的洞察力和知识将为未来开发新的疾病修改疗法类别和更全面地解释疾病进展调查提供更坚实的基础。

DESCRIPTION (provided by applicant): A primary pathological component of Alzheimer's disease (AD) is brain inflammation. Activation of microglia, the "macrophages of the brain", is known to occur in AD and believed to contribute to the neuronal damage. Studies of peripheral macrophages have determined that multiple distinct activation states of macrophages exist, and recent studies have confirmed these findings in microglia. Macrophages/microglia can be broadly defined as being classically activated or alternatively activated. Classically activated macrophages are typified by the release of proinflammatory cytokines (e.g. IL-12, TNF-1) and reactive oxygen and nitrogen species, which are components of the inflammatory response that is known to cause neuronal damage. However, not all forms of microglia activation are detrimental. Some forms of microglia activation are beneficial, such as alternative activation responses that lead to removal or clearance of amyloid beta (A2). This proposal will test the hypothesis that the p381 MAP kinase signaling cascade leads to the detrimental forms of microglia activation, and that blocking the p381 pathway will decrease the detrimental responses of activated microglia without affecting the beneficial responses. Aim 1 will test the hypothesis that activation of the p381 MAP kinase signaling cascade occurs in microglia during the early phase of pathogenesis in an AD-relevant transgenic mouse model (the Tg6799 mouse). Aim 2 will use a novel, brain-penetrant, small molecule inhibitor of p381 to test the hypothesis that suppression of p381 activity will slow the pathology in the Tg6799 mouse. This aim will provide training in the use of pharmacological tools, transgenic models of neurodegenerative disease, and therapeutic target validation. Aim 3 will evaluate the relative contribution of p381 in microglia vs. other neural cell types in the damage produced by A2. To test this aim, we will use an A2 infusion AD-relevant model in a mouse with a genetic deletion of p381 only in the microglia. This aim will provide training in the use of conditional knockout mouse models using the cre/lox system, and stereotaxic surgery in mice. Successful completion of this project will provide mechanistic insight into how the key regulatory protein p381 is involved in CNS pathophysiology mechanisms and intervention responses, and will form the foundation for follow-on CNS therapeutic development campaigns targeting this important protein kinase. A Career Development Plan has been formalized, and includes a combination of formal classroom and specialty workshop participation, regular presentations of proposed research plans and results at the laboratory and research group level, presentation of independent research results in seminar format, participation in national and international scientific meetings, preparation of research proposals and publications, and development of additional career- enhancing skills. An experienced mentor, a rich scientific environment, and an organized educational and training plan will assure that the applicant has optimal opportunities for scientific growth, career enhancement and development into an independent academic investigator. PUBLIC HEALTH RELEVANCE: Neuroinflammation is increasingly being recognized as a contributor to pathology in many neurodegenerative diseases, such as Alzheimer's disease, a devastating disease of aging with no effective treatment or cure. Successful completion of this project will provide mechanistic insight into how the key regulatory protein, p381 MAPK, is involved in brain pro-inflammatory responses and CNS dysfunction caused by disease-relevant stressors. In addition, the results will delineate the relative importance of microglial p381 MAPK to the disease-relevant pathological responses. Longer term, the insights and knowledge generated by the proposed studies will provide a firmer foundation for future development of new classes of disease- modifying therapeutics and fuller interpretation of disease progression investigations.