Disruptions of the BBB During Hypoxia/Reoxygenation

描述（由申请人提供）：血脑屏障（BBB）是一种物理和代谢屏障，将外周循环与中枢神经系统（CNS）隔开，并用于调节和保护大脑的微环境。BBB的破坏发生在许多病理状况中，包括炎性调节障碍、阿尔茨海默病、糖尿病、多发性硬化和缺血/再灌注。缺氧和复氧与缺血和再灌注的变化相关，与显著影响BBB的各种疾病状态相关，随后影响更敏感的神经组织。阐明由缺氧（H）和/或缺氧后再氧合（H/R）诱导的BBB改变的程度和方式仍然是一项相当大的任务。在这种条件下，检查细胞内通路，转录因子和紧密连接蛋白的调节和激活对于理解这些BBB改变至关重要。本次提交的总体目标是确定缺氧/缺氧后复氧暴露期间导致BBB结构和功能变化的细胞内信号传导机制（蛋白激酶C和转录因子）。这些研究将集中于H和H/R对信号分子、蛋白激酶C和转录因子HIF 1和NF κ B的影响，以及这些介质如何促进BBB破坏，从而导致血管源性脑水肿，这是与缺血性卒中相关的主要因素。我们的假设是，BBB的功能变化是由于内皮细胞的细胞结构的改变而发生的，内皮细胞的细胞结构的改变是由缺氧和/或缺氧后再氧合损伤刺激的细胞内机制/介质引起的。为了研究这一假设，我们的目的和具体目标是通过检查BBB通透性变化、紧密连接/细胞骨架蛋白表达和定位以及转录因子表达/激活与细胞信号传导途径/机制（PKC）的变化，来检查H和H/R损伤对BBB毛细血管内皮细胞的影响。本研究需要使用多种技术并在体外整合两者（即，大鼠脑微血管内皮细胞）和体内（即，Sprague-Dawley大鼠脑微血管）模型，使我们能够区分和相关的细胞信号转导途径的功能和结构的变化与BBB扰动后H和H/R损伤。我们的目标是更好地了解与BBB缺血性卒中相关的缺氧机制，从而获得更好的治疗模式。

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.