Disruptions of the BBB During Hypoxia/Reoxygenation

描述(申请人提供)：血脑屏障(BBB)是将外周循环与中枢神经系统(CNS)隔开的物理和代谢屏障，用于调节和保护大脑的微环境。血脑屏障的破坏发生在许多病理情况下，包括炎症调节障碍、阿尔茨海默病、糖尿病、多发性硬化症和缺血/再灌注。缺氧和复氧与缺血和再灌注的变化相关，与各种疾病状态相关，这些疾病状态显著影响血脑屏障，从而对更敏感的神经组织产生影响。阐明低氧(H)和/或低氧后复氧(H/R)引起的血脑屏障改变的程度和方式仍然是一个相当大的任务。研究细胞内途径、转录因子和紧密连接蛋白在这种条件下的调节和激活对于理解这些BBB变化至关重要。本论文的总体目标是确定在低氧/缺氧后复氧暴露期间导致血脑屏障结构和功能变化的细胞内信号机制(蛋白激酶C和转录因子)。这些研究将集中在H和H/R对信号分子蛋白激酶C和转录因子HIF1和NFKappaB的影响，以及这些介质如何参与血脑屏障的破坏，从而导致血管源性脑水肿，血管源性脑水肿是与缺血性中风相关的主要因素。我们的假设是，由于缺氧和/或缺氧后复氧损伤刺激的细胞内机制/介质，内皮细胞的细胞结构发生了变化，导致血脑屏障的功能改变。为了研究这一假说，我们的目标和具体目的是通过检测血脑屏障通透性的变化、紧密连接/细胞骨架蛋白的表达和定位、转录因子表达/激活的变化以及细胞信号通路/机制(PKC)来研究H和H/R损伤对血脑屏障毛细血管内皮细胞的影响。这项研究需要使用多种技术，并整合体外(即大鼠脑微血管内皮细胞)和体内(即SD-Dawley大鼠脑微血管)模型，以使我们能够区分和关联与H和H/R损伤后BBB扰动相关的功能和结构变化的细胞信号通路。我们的目标是更好地了解血脑屏障低氧与缺血性卒中相关的机制，从而产生更好的治疗范例。

DESCRIPTION (provided by applicant): The blood-brain barrier (BBB) is a physical and metabolic barrier that separates the peripheral circulation from the central nervous system (CNS) and serves to regulate and protect the microenvironment of the brain. Disruption of the BBB occurs in a number of pathological conditions, including inflammatory regulated disorders, Alzheimer's disease, diabetes, multiple sclerosis, and ischemia/reperfusion. Hypoxia and reoxygenation correlate with changes in ischemia and reperfusion, are associated with various disease states which significantly influence the BBB, with subsequent effects in more sensitive neural tissue. Clarifying the extent and manner of BBB alterations induced by the hypoxia (H) and/or post-hypoxic reoxygenation (H/R), remains a considerable task. Examination of the regulation and activation of intracellular pathways, transcription factors, and tight junction proteins under such conditions is vital to understanding these BBB alterations. The overall goal of this submission is to determine the intracellular signaling mechanisms (protein kinase C and transcription factors) responsible for BBB structural and functional changes during hypoxia/post-hypoxic reoxygenation exposure. These studies will focus on the effects of H and H/R on the signaling molecule, protein kinase C, and the transcription factors, HIF1 and NFKappaB, and how these mediators contribute to BBB disruptions which lead to vasogenic brain edema, a major factor associated with ischemic stroke. Our hypothesis is that functional changes at the BBB occur due to alterations in the cytoarchitecture of the endothelial cell as a result of intracellular mechanisms/ mediators stimulated by hypoxia and/or post-hypoxic reoxvqenation insult. To investigate this hypothesis, our objectives and Specific Aims are to examine the effects of H and H/R insult on capillary endothelial cells of the BBB, by examining BBB permeability changes, tight junction/ cytoskeletal protein expression and localization, and changes in transcription factor expression/activation in conjunction with cellular signaling pathways/mechanisms (PKC). This study requires the use of multiple techniques and the integration of both in vitro (i.e., rat cerebral microvessel endothelial cells) and in vivo (i.e., Sprague-Dawley rat cerebral microvessel) models to allow us to differentiate and correlate cellular signaling pathways to functional and structural changes associated with BBB perturbation following H and H/R insult. Our goal is to gain a better understanding on the mechanisms involved in hypoxia associated with ischemic stroke at the BBB, leading to better treatment paradigms.