Age-dependent microglial responses in hypoxia-ischemia

个人描述(申请人提供)：我的总体职业目标是成为儿科脑损伤研究领域的领军人物。我对神经发育对脑缺血反应的影响的兴趣源于我作为一名儿科重症监护医生照顾脑损伤儿童的临床经验。在过去的5年里，我在小动物MRI在脑缺血啮齿动物模型中的应用方面积累了专业知识。在培训期间，我将获得更多关于尖端神经成像技术和方法的经验，以评估发育中大脑中小胶质细胞反应的分子机制。一种新的PET/MR成像技术的个性化验证培训将为我提供所需的专业知识，以开发创新的成像技术来研究HI后的神经炎症。我将通过威斯康星大学的临床和翻译研究所学习统计学、成像方法、免疫学和发育神经生物学的正式课程。加州大学旧金山分校的维克斯勒实验室和萨法尔复苏研究中心的克拉克实验室将提供关于评估神经细胞死亡以及评估和抑制HI后小胶质细胞激活的新技术的培训。为了培养将我的临床前影像研究转化为临床应用所需的技能，并开始在该领域建立声誉，我将参加儿科神经危重护理研究小组，这是一个多机构转换研究网络。我会继续指导脑部损伤 这将提高我对儿童脑损伤结果的理解，并为未来的临床试验建立一个衡量结果的框架。所有这些步骤都将有助于我成功地过渡到独立。环境：威斯康星大学是美国一流的研究机构之一，校园里有170多名神经学家。儿科为一名研究助理提供启动资金、实验室空间和工资支持，以及每年9个月的受保护研究时间。我的实验室位于韦斯曼发育障碍研究中心，是进行发育性脑损伤转化性研究的理想环境。韦斯曼中心拥有我的导师和其他发育性脑损伤和神经成像专家的实验室，并提供动物成像、行为测试、显微镜和流式细胞术的核心设施资源。我们组建了一支经验丰富的导师团队，他们在对我的研究至关重要的领域拥有专业知识：缺血、髓鞘疾病和神经炎症的分子机制，以及临床前和临床神经成像。这种最佳的研究环境将确保我成功地过渡到一名独立的内科科学家。研究：美国每年有2万多名婴儿和儿童受到脑缺血影响，治疗选择有限。减轻缺血引起的神经炎性反应的治疗已被认为是一种很有前途的神经保护策略。然而，小胶质细胞介导的炎症反应在发育中的大脑中对缺血的了解还不是很清楚。在未成熟的脑中，小胶质细胞在突触形成过程中被激活以吞噬细胞碎片，目前尚不清楚这种激活的小胶质细胞的优势如何影响缺血性损伤。在我们的初步研究中，我们发现小胶质细胞对缺氧-缺血(HI)的反应存在区域和发育差异：与其他脑区相比，出生后第9天(P9)小鼠海马区的小胶质细胞早期激活，与P30小鼠相比，小胶质细胞反应增强。我们假设，未成熟脑中小胶质细胞的持续分化和激活使其容易对HI产生比青少年和成人脑更强烈的促炎反应，并且小胶质细胞反应的年龄和区域差异导致不同的神经元损伤。这些假说将在以下目标中进行检验：具体目标1：检验我们的假说，即未成熟脑损伤前增加的小胶质细胞激活有助于更有力的小胶质细胞对 嗨。具体目标2：使用小胶质细胞抑制方法测试我们的假设，即小胶质细胞反应的区域和年龄相关的差异导致不同的神经元损伤轮廓。综上所述，这项研究提案将探讨小胶质细胞对缺血的反应是发育调节的这一新假说。这项研究的完成将为了解发育中的脑缺氧缺血后小胶质细胞的功能提供新的线索，并确定HI后抑制小胶质细胞的潜在益处。完成高级神经成像、神经炎症和翻译研究方面的培训计划将为我提供一套独特的技能，使我能够利用我在神经危重护理方面的临床专业知识，并开发新的 针对儿童脑缺血神经炎性反应的治疗策略。好了！

DESCRIPTION (provided by applicant): My overall career goal is to become a leader in the field of pediatric brain injury research. My interest in the effect of neurodevelopment on responses to cerebral ischemia is rooted in my clinical experience caring for children with brain injury as a Pediatric Critical Care Physician. Over the past 5 years, I have developed an expertise in the use of small animal MRI in rodent models of cerebral ischemia. During the training period, I will gain additional experience in cutting edge neuroimaging techniques and methods for assessing molecular mechanisms of microglial responses in the developing brain. An individualized training in validation of a novel PET/MR imaging technique will provide me with the expertise I need to develop innovative imaging techniques for studying neuroinflammation after HI. I will take formal coursework through the University of Wisconsin's Institute for Clinical and Translational Research in statistics, imaging methods, immunology, and developmental neurobiology. Externships to the Vexler Lab at UCSF and the Clark Lab at the Safar Center for Resuscitation Research will provide training in new techniques for assessing neuronal cell death and for assessing and inhibiting microglial activation post-HI. To develop the skills necessary to translate my pre-clinical imaging studies into clinical use, and to begin to establish a reputation in the field, I will participate in the Pediatric Neurocritical Care Researc Group, a multi-institution translational research network. I will continue to direct a brain injury follow-up clinic, which will improve my understanding of outcomes from pediatric brain injury, and create a framework for measuring outcomes in future clinical trials. All of these steps will facilitate my successful transition to independence. Environment: The University of Wisconsin is one of the premier research institutions in the United States with over 170 neuroscientists on campus. The Department of Pediatrics has provided start-up funds, lab space, and salary support for a research associate, and 9 months of protected research time per year. The location of my lab at the Waisman Center for Developmental Disabilities research is the ideal environment for conducting translational research in developmental brain injuries. The Waisman Center houses the labs of my Mentors and other experts in developmental brain injuries and neuroimaging, and provides core facility resources for animal imaging, behavioral testing, microscopy, and flow cytometry. We have assembled a team of experienced mentors with expertise in the fields vital to my research: molecular mechanisms of ischemia, myelinopathies, and neuroinflammation, and pre-clinical and clinical neuro-imaging. This optimal research environment will ensure that my transition into an independent physician scientist is successful. Research: Cerebral ischemia affects over 20,000 infants and children every year in the US, and treatment options are limited. Therapies that mitigate the neuroinflammatory response to ischemia have been recognized as a promising neuroprotective strategy. However, the microglia-mediated inflammatory response to ischemia in the developing brain is not well understood. In the immature brain, microglial cells are activated for phagocytosis of cellular debris during synaptogenesis, and it is unknown how this predominance of activated microglia impacts ischemic injury. In our preliminary studies we found both regional and developmental differences in microglial responses to hypoxia-ischemia (HI): early microglia activation in the hippocampus compared to other brain regions, and increased microglial responses in postnatal day 9 (P9) mice compared to P30 mice. We hypothesize that the ongoing differentiation and activation of microglia in the immature brain predisposes it to a more vigorous pro-inflammatory response to HI than juvenile and adult brains, and that age- and region- dependent differences in microglial responses result in different profiles of neuronal injury. These hypotheses will be tested in the following aims: Specific Aim 1: Test our hypothesis that increased microglial activation prior to injury in immature brains contributes to a more vigorous microglial response to HI. Specific Aim 2: Test our hypothesis that region- and age-dependent differences in microglial responses result in different profiles of neuronal injury using a microglial inhibition approach. I summary, this research proposal will investigate the novel hypothesis that the microglia response to ischemia is developmentally regulated. The completion of this study will shed new light on microglia function after hypoxia- ischemia in the developing brain, and determine the potential benefit of microglial inhibition after HI. Completion of the Training Plan in advanced neuroimaging, neuroinflammation, and translational research will provide me with a unique skill set that will allow me to capitalize on my clinical expertise in neurocritical care and develop new treatment strategies targeting the neuroinflammatory response to pediatric cerebral ischemia. !