Cyclooxygenase-2 Regulation of Blood-Brain Barrier Opening in Ischemic Stroke

描述（由申请人提供）：神经炎症导致缺血性卒中的进行性损伤。缺血性卒中后24 - 48 h发生的血脑屏障（BBB）破坏是导致神经元死亡的病理机制。目前迫切需要确定限制中风后继发性损害的药理学策略。环氧合酶（考克斯）-2/前列腺素E2（PGE 2）通路积极参与加重初始缺血性脑损伤的炎症事件。我们的长期目标是了解如何操纵考克斯-2/PGE 2通路来阻断缺血性卒中后的进行性损伤级联反应。本项目的总体目标是确定增加的考克斯-2/PGE 2如何介导缺血性卒中中的BBB损伤和神经元死亡。我们的中心假设是抑制考克斯-2/PGE 2通路通过减少MMP-3/-9的产生来保护BBB损伤和神经元死亡。这项研究的基本原理是，了解考克斯-2/PGE 2在中风中的急性（有害）和晚期（可能有益）作用的机制，应该为阻断考克斯-2/PGE 2通路的药物更有选择性和更有效的治疗干预确定新的靶点。 具体目标#1：确定缺血后考克斯-2介导的MMP-3/-9表达/活性增加和BBB损伤的下游效应物。为此目的的实验检验了这样的假设，即在局灶性缺血性脑损伤中，考克斯-2衍生的PGE 2通过激活特异性EP受体诱导MMP-3/-9产生和BBB破坏。我们将在一个完善的缺血性中风大鼠模型中利用体内药理学方法。这将与EP受体和MMP-3/-9的免疫组织化学、免疫印迹和生物化学分析相结合。 具体目标#2：确定调节考克斯-2/PGE 2途径的药物的保护和长期作用的治疗时间窗。该目的的实验检验了以下假设：用阻断缺血诱导的PGE 2形成/信号传导的试剂进行缺血后治疗提供神经保护而不干扰后期恢复阶段。我们将利用体内药理学方法，结合创新的MRI技术和一系列测试来评估神经功能。MRI方法将与免疫组织化学分析相结合，以测量神经发生和血管生成。 我们期望这项研究将提供有关考克斯-2衍生的PGE 2及其EP受体对缺血性中风后神经炎症过程的贡献的重要知识。我们还希望确定一个临床相关的治疗时间窗口的管理药物靶向考克斯-2/PGE 2。这些结果将有望产生重要的积极影响，因为它们将确定新的和急需的方法，以减少中风引起的BBB损伤的破坏性后果。

DESCRIPTION (provided by applicant): Neuroinflammation leads to progressive damage in ischemic stroke. Disruption of the blood-brain barrier (BBB) occurring at 24-48 h following ischemic stroke is a pathological mechanism that contributes to neuronal death. There is an urgent need to identify pharmacological strategies that limit the secondary damage following stroke. The cyclooxygenase (COX)-2/prostaglandin E2 (PGE2) pathway is actively involved in inflammatory events that exacerbate initial ischemic brain injury. Our long-term goal is to understand how the COX-2/PGE2 pathway can be manipulated to block the progressive injury cascade following ischemic stroke. The overall objective of this project is to determine how increased COX-2/PGE2 mediates BBB damage and neuronal death in ischemic stroke. Our central hypothesis is that inhibition of the COX-2/PGE2 pathway protects against BBB damage and neuronal death by reducing MMP-3/-9 production. The rationale for the proposed research is that understanding the mechanisms involved in acute (deleterious) and late (possibly beneficial) effects of COX-2/PGE2 in stroke should identify novel targets for a more selective and effective therapeutic intervention with drugs blocking the COX-2/PGE2 pathway. Specific Aim #1: To identify the downstream effectors of COX-2-mediated increase in MMP-3/-9 expression/activity and damage to the BBB after ischemia. Experiments in this aim test the hypothesis that COX-2-derived PGE2 induces MMP-3/-9 production and BBB breakdown through activation of specific EP receptor(s) in focal ischemic brain injury. We will utilize an in vivo pharmacological approach in a well- established rat model of ischemic stroke. This will be coupled with immunohistochemical, immunoblotting and biochemical analyses of EP receptors and MMP-3/-9. Specific Aim #2: To determine the therapeutic time window of protection and long-term effects of drugs modulating the COX-2/PGE2 pathway. Experiments in this aim test the hypothesis is that post- ischemic treatment with agents blocking ischemia-induced PGE2 formation/signaling provides neuroprotection without interfering in the late recovery phase. We will utilize an in vivo pharmacological approach together with innovative MRI techniques and a battery of tests to evaluate neurological function. The MRI approach will be coupled with immunohistochemical analyses to measure neurogenesis and angiogenesis. It is our expectation that this research will provide significant knowledge of the contribution of COX-2- derived PGE2 and its EP receptors to the neuroinflammatory process that follows ischemic stroke. We also expect to identify a clinically relevant therapeutic time window for the administration of drugs targeting COX- 2/PGE2. Such results would be expected to have an important positive impact, since they would identify novel and much-needed approaches to reduce the devastating consequences of stroke-induced BBB damage.