Protective mechanisms of ischemic postconditioning

描述（由申请人提供）：目前缺乏有效的急性卒中治疗方法，需要探索最终可能导致临床应用的创新概念。一种这样的技术是缺血后处理。我们已经证明，快速和延迟缺血后处理减少大鼠梗死。通过30分钟bCCA闭塞加永久性远端大脑中动脉（MCA）闭塞诱导卒中。bCCA释放允许部分再灌注，这模拟了中风患者中发生的常见临床病例。再灌注后立即应用快速后处理，而再灌注后5.5 h进行延迟后处理。尽管几个独立的研究小组证实了后处理的保护作用，但其潜在的保护机制尚不清楚。我们有初步的数据表明，快速后处理减弱活性氧（ROS）的活性，表明后处理和ROS减少之间的相关性。ROS的减少是否真的有助于后处理的保护作用尚不清楚。此外，ROS活性直接导致神经元存活信号通路Akt/PRAS 40通路的功能障碍，并且Akt功能障碍导致炎症。然而，Akt/PRAS 40通路和炎症在缺血后处理保护作用中的作用尚未得到充分研究。在这项研究中，我们将首先确定参与后处理保护作用的ROS活性的亚细胞来源。然后，我们将在大鼠和PRAS 40基因敲除小鼠中研究ROS减少与Akt/PRAS 40活性之间的关系，这从未在任何研究中使用过。最后，我们将研究Akt/PRAS 40如何调节炎症反应，包括其对促炎因子HMGB 1和考克斯-2的影响，以及新的galectin-9/Tim-3炎症通路。通过这些研究，我们将填补我们对缺血后处理的保护机制和临床翻译知识的重大空白。 具体目标1。确定在缺血后处理的保护作用中起关键作用的ROS减少的亚细胞调节源。 具体目标2。研究ROS抑制是否能提高Akt/PRAS 40活性。 具体目标3。检测Akt/PRAS 40通路对HMGB 1和考克斯-2的促炎反应以及半乳糖凝集素-9/Tim-3炎症通路的保护作用。

DESCRIPTION (provided by applicant): The current lack of effective treatments for acute stroke necessitates exploring innovative concepts that may eventually lead to clinical applications. One such technique is ischemic postconditioning. We have demonstrated that both rapid and delayed ischemic postconditioning reduces infarction in rats. Stroke was induced by a 30 min bCCA occlusion plus permanent distal middle cerebral artery (MCA) occlusion. The bCCA release allows partial reperfusion, which mimics the frequent clinical cases that occur in stroke patients. Rapid postconditioning is applied immediately after reperfusion while delayed postconditioning is conducted 5.5 h after reperfusion. Despite confirmation of the protective effects of postconditioning by several independent research groups, the underlying protective mechanisms are not understood. We have preliminary data showing that rapid postconditioning attenuates reactive oxygen species (ROS) activity, suggesting a correlation between postconditioning and ROS reduction. Whether ROS reduction truly contributes to postconditioning's protective effects is not known. In addition, ROS activity directly results in dysfunction of the neuronal survival signaling pathway, Akt/PRAS40 pathway, and Akt dysfunction leads to inflammation. However, the roles of the Akt/PRAS40 pathway and inflammation in the protective effects of ischemic postconditioning have not been well studied. In this grant, we will first identify subcellular sources of ROS activity that are involved in postconditioning's protective effects. We will then study the relationship between ROS reduction and Akt/PRAS40 activity in both rats and PRAS40 knockout mice, which has never been used in any studies. Finally, we will study how Akt/PRAS40 regulates the inflammatory response, including its effects on the pro-inflammatory factors HMGB1 and Cox-2, and the novel galectin-9/Tim-3 inflammatory pathway. Through these studies, we will fill significant gaps in our knowledge about the protective mechanisms and clinical translation of ischemic postconditioning. Specific Aim 1. To identify the subcellular regulatory sources of ROS reduction that play critical roles in the protective effects of ischemic postconditioning. Specific Aim 2. To study whether ROS inhibition improves the Akt/PRAS40 activity. Specific Aim 3. To examine the protective effects of the Akt/PRAS40 pathway on the pro-inflammatory response of HMGB1 and Cox-2, and the galectin-9/Tim-3 inflammatory pathway.