Injury Mechanisms and Systemic Immune Responses after Cerebral Global Ischemia

描述(申请人提供)：这个合作项目汇集了两个研究团队，他们在(1)因心脏骤停和复苏导致的全脑缺血后再灌注损伤的治疗方面拥有20多年的联合研究经验，(2) 神经损伤的机制和通过系统免疫反应的保护，以及(3)向中枢神经系统(CNS)的全身性药物输送。在寻找使用成人干细胞有效治疗全球脑缺血的过程中，研究人员偶然发现了一种通过细胞信号而不是转分化或干细胞/宿主细胞融合来保护干细胞的新机制。最重要的是，研究人员发现，这一信号传递过程可以强烈地调节对全球缺血的炎症反应，并通过防止对神经胶质细胞的促炎损伤来保护选择性脆弱的神经元。该项目的主要目的是从机制上理解全脑缺血时全身和脑免疫反应之间的耦合，从而开发一种系统的治疗策略来接近心脏骤停后的神经元修复。中心假设是，复苏后再灌注后期的大部分播散性神经元丢失可以通过调整免疫系统来关闭促炎反应和开启保护性免疫激活来预防和逆转。一种创新的方法被提出，以劫持免疫细胞的自然修复潜力，并为以前未知的治疗领域塑造其细胞因子的功能性分泌。一种临床相关的小鼠心脏骤停和复苏结局模型已经被开发出来，以允许在控制良好的心脏骤停和复苏后使用部分和完全免疫缺陷的转基因小鼠进行纵向生存研究。这个项目的具体目标是 具体目标是：1：建立免疫完全野生型小鼠心脏骤停后全脑缺血再灌注损伤的全身和脑免疫反应之间的相关性；具体目标2：利用部分和完全免疫缺陷转基因小鼠鉴定和区分促炎症细胞因子和抗炎细胞因子在神经元损伤和修复中的免疫贡献；特殊目标3：设计骨髓来源的巨噬细胞和树突状细胞以恢复部分和完全免疫缺陷小鼠的靶向免疫反应，以实现对神经元损伤和保护中系统免疫反应的潜在过程的机制了解；具体目标4：开发可能的体内后治疗策略，重点是在心脏骤停和复苏后，使用RNA干扰技术在野生型小鼠中重新平衡促炎和抗炎细胞因子。这些具体的研究将为最终确定治疗心脏骤停后全球缺血的最有效策略铺平道路。 并在从桌面到床边的新机械理解上架起桥梁。

DESCRIPTION (provided by applicant): This collaborative project brings together two investigative teams with over two decades of combined research experience in (1) the treatment of reperfusion injuries after global cerebral ischemia due to cardiac arrest and resuscitation, (2) mechanisms of neuronal injury and protection through systemic immune responses, and (3) systemic drug delivery to the central nervous system (CNS). In their search for effective treatment of global cerebral ischemia using adult stem cells, the investigators serendipitously discovered a novel mechanism of stem cell protection through cell signaling instead of transdifferentiation or stem-cell/host-cell fusion. Most importantly, the investigators found that this signaling process can strongly modulate the inflammation response to global ischemia and render protection to selectively vulnerable neurons by preventing pro- inflammatory damage to glial cells. The main objective of this project is to achieve a mechanistic understanding of the coupling between systemic and brain immune responses to global cerebral ischemia, thereby developing a systemic treatment strategy to approach neuronal repair after cardiac arrest. The central hypothesis is that most of the disseminated neuronal loss in the later phase of reperfusion after resuscitation can be prevented and reversed by tailoring the immune system to turn off pro-inflammatory responses and turn on protective immune activation. An innovative approach is proposed to hijack the immune cells' natural repairing potential and to shape their functional secretion of cytokines for a previously uncharted therapeutic territory. A clinically relevant outcome model of cardiac arrest and resuscitation in mice has been developed to allow the use of partially and completely immunodeficient transgenic mice in longitudinal survival studies after a well-controlled cardiac arrest and resuscitation. The specific aims of this project are: Specific Aim 1: To establish correlations between systemic and brain immune responses to global cerebral ischemia and reperfusion injuries after clinically relevant cardiac arrest in immunocomplete wild-type mice; Specific Aim 2: To use partially and completely immunodeficient transgenic mice to identify and differentiate immune contributions from pro- and anti-inflammatory cytokines in neuronal injury and repair; Specific Aim 3: To engineer bone-marrow-derived macrophagic and dendritic cells to restore the targeted immune response in partially and completely immunodeficient mice to achieve a mechanistic understanding of the underlying processes in systemic immune responses in neuronal injury and protection; and Specific Aim 4: To develop possible in vivo post-treatment strategies focusing on rebalancing the pro- and anti-inflammatory cytokines using RNA-interference technology in wild-type mice after cardiac arrest and resuscitation. These specific investigations will pave the way to ultimately identifying the most effective strategies to treat global ischemia after cardiac arrest, and to bridge new mechanistic understandings from benchtop to bedside.