The role of Cannabinoid Receptor 2 in cerebrovascular protection following traumatic brain injury

项目摘要/摘要 创伤性脑损伤(TBI)是美国与伤害相关的死亡和残疾的主要原因 全世界。头部受到撞击、打击或震动或穿透性脑损伤后，脑损伤会扰乱正常的大脑。 功能分为两个阶段：首先，原发损伤发生在撞击的瞬间，后来，免疫/炎症 反应，也称为继发性损伤。继发性损伤期间发生的炎症反应可能 极大地促进了神经变化，包括认知障碍、执行功能障碍、情绪 和行为失调症。目前，还没有批准的治疗脑损伤的药物治疗，尽管 近十年来，颅脑损伤的发病率呈上升趋势。因此，对小说的需求十分迫切 控制异常二次损伤反应的药理靶点。颅脑损伤病理的标志性特征 血管破裂和血脑屏障(BBB)高通透性。针对目标群体的战略 神经血管学可能为新的有效疗法打开大门。已知内源性大麻素 系统是神经元动态平衡和免疫功能的主要调节者。内源性大麻素系统， 大麻素2受体(CB2)是炎症消退的主要贡献者。重要的是，我们的实验室 先前显示CB2在脑微血管内皮细胞低基础水平表达，并且是 在神经炎症期间表达上调。然而，TBI研究的一个未被研究的方面是CB2的动力学 以及它作为脑血管内皮细胞水平的治疗靶点的潜力。具体地说，我们在这里探索 新型CB2激动剂恢复实验性神经损伤后血脑屏障完整性的能力。初步数据 体外使用合成的基于铬并吡唑的CB2激动剂，具有更高的亲和力和溶解性， 证明在恢复血脑屏障功能和减弱内皮细胞激活方面有改善。此外, 从撞击区域分离的微血管中的基因表达分析显示， CNR2基因，编码CB2。因此，我们假设脑损伤后内皮细胞CB2的激活 促进血脑屏障修复和血管保护。这一假设将使用以下具体的方法进行探讨 目的：1)研究血管内皮细胞损伤后CB2表达的受体动态变化及治疗 有效的CB2激动剂在体外和体内脑损伤模型中提供血管保护的可能性。这些 研究以先进的成像技术、神经行为评估和新的高度特异的CB2为特色 激动剂，2)鉴定连接CB2受体信号与途径的分子机制 调节血脑屏障功能。综上所述，这项研究提出的目标将有助于深入了解脑损伤的机制-- 病理学和新型CB2激动剂对抗神经炎症有害影响的有效性。

PROJECT SUMMARY/ABSTRACT Traumatic brain injury (TBI) is the leading cause of injury-related death and disability in the United States and worldwide. The result of a bump, blow, or jolt to the head or penetrating brain injury, TBI disrupts normal brain function in two stages: first, the primary injury at the moment of impact, and later, the immune/inflammatory response, also called secondary injury. The inflammatory response that occurs during secondary injury can contribute greatly to neurological changes including cognitive impairment, executive function deficits, emotional and behavioral dysregulation. Currently, there are no approved pharmacological treatments for TBI despite the incidence of TBI increasing over the past decade. Consequently, there is an urgent need for novel pharmacological targets to control the aberrant secondary injury response. A hallmark feature of TBI pathology is vascular disruption and Blood Brain Barrier (BBB) hyperpermeability. Strategies that target the neurovasculature could open the door to new, effective therapeutics. It is known that the endocannabinoid system is a major regulator of neuronal homeostasis and immune function. Of the endocannabinoid system, the Cannabinoid 2 Receptor (CB2) is a major contributor to inflammation resolution. Importantly, our lab previously showed CB2 is expressed at low basal levels on cerebral microvascular endothelial cells and is upregulated during neuroinflammation. However, an unstudied aspect of TBI research is the kinetics of CB2 and its potential as a therapeutic target at the level of the cerebral endothelium. Specifically, here we explore the ability of novel CB2 agonists to restore BBB integrity following experimental neurotrauma. Preliminary data in vitro using synthetic chromenopyrazole based CB2 agonists, featuring increased affinity and solubility, demonstrate improvements in restoring BBB function and attenuating endothelial activation. In addition, analysis of gene expression in microvessels isolated from the area of impact shows rapid upregulation of the CNR2 gene, which encodes for CB2. Therefore, we hypothesize that activation of endothelial CB2 following TBI promotes BBB repair and vascular protection. This hypothesis will be explored using the following specific aims: 1) to characterize the receptor dynamics of endothelial CB2 expression post-injury and the therapeutic potential for potent CB2 agonists to provide vascular protection in both in vitro and in vivo models of TBI. These studies feature advanced imaging techniques, neurobehavioral evaluations and novel highly specific CB2 agonists, 2) Identification of molecular mechanisms that bridge CB2 receptor signaling with pathways that modulate BBB function. Together the aims proposed in this study will provide insight into mechanisms of TBI- pathology and the effectiveness of novel CB2 agonists against the harmful effects of neuroinflammation.