Endogenous and exogenous protection of the BBB in stroke

描述（由申请人提供）：卒中中BBB的内源性和外源性保护。血脑屏障（BBB）功能障碍发生在多种神经系统疾病和损伤（例如中风）中。这种功能障碍可能通过增强白细胞流入大脑，允许潜在的神经毒性血液成分进入并引起血管源性水肿而参与这些状态。此外，它可能影响疾病治疗（例如，出血性转化是使用组织纤溶酶原激活剂诱导的再灌注治疗缺血性卒中的主要限制因素）。因此，非常需要保护BBB的方法。通过检查疾病状态下哪些内源性机制发生改变，可能会确定治疗靶点。我们已经证明，预处理刺激可以保护血脑屏障和脑内皮细胞在体内和体外。我们还表明，中风相关因素导致脑内皮细胞中胱氨酸/谷氨酸交换（系统XC-），细胞内谷胱甘肽的调节剂的表达显着增加。该交换器受nrf 2（一种抗氧化转录因子）调节，xc-可通过暴露于萝卜硫素（一种Nrf 2的激活剂和十字花科蔬菜的组分）而显著上调。这些结果使我们假设：Nrf 2及其调节的蛋白质（例如xCT，血红素加氧酶1和铁蛋白）可能是保护BBB的靶点。由于Nrf 2调节这些蛋白质需要蛋白质合成，我们还假设该系统的功能是防止延迟的BBB破坏，特别是由于缺血中白细胞的迁移。这些假设将在五个具体目标中进行检验：1+2）确定中风相关因子、炎症介质或萝卜硫素对系统xc-的上调是否具有保护作用。3+4）确定中风或炎症后脑内皮中Nrf 2是否被激活，以及其激活和下游蛋白的上调是否会保护脑内皮。5)检查用萝卜硫素治疗是否可以保护体内的BBB。这些特定的目的将在体外进行检查，以阐明分子机制，并在体内，以确定病理生理学相关性。结果应强调内源性血脑屏障保护机制和潜在的外源性化合物激活或抑制这些机制。公共卫生相关性：脑血管具有非常特殊的功能，形成血脑屏障。这种屏障的破坏发生在许多神经系统疾病和损伤中，导致脑功能障碍。该提案研究了可能保护血脑屏障的自然防御机制，如何激活这些机制或在治疗上防止其失活。

DESCRIPTION (provided by applicant): Endogenous and exogenous protection of the BBB in stroke. Blood-brain barrier (BBB) dysfunction occurs in a wide variety of neurological diseases and injuries (e.g. stroke). Such dysfunction may participate in those states by enhancing the influx of leukocytes into the brain, allowing the entry of potentially neurotoxic blood components and causing vasogenic edema. In addition, it may affect disease treatment (e.g. hemorrhagic transformation is a major limiting factor for the use of tissue plasminogen activator-induced reperfusion therapy for ischemic stroke). There is, therefore, a great need for methods to protect the BBB. Therapeutic targets may potentially be identified by examining which endogenous mechanisms are altered in disease states. We have shown that preconditioning stimuli can protect the BBB and cerebral endothelial cells in vivo and in vitro. We have also shown that stroke-related factors cause a marked increase in the expression of the cystine/glutamate exchanger (system xc-), a regulator of intracellular glutathione, in cerebral endothelial cells. This exchanger is regulated by nrf2 (an anti-oxidant transcription factor) and xc- can be markedly upregulated by exposure to sulforaphane, an activator of Nrf2 and a component of cruciferous vegetables. These results have led us to hypothesize that: Nrf2 and the proteins it regulates (e.g. xCT, heme oxygenase 1 and ferritin) may be a target for protecting the BBB. As Nrf2 regulation of these proteins requires protein synthesis, we also hypothesize that the function of this system is to protect against delayed BBB disruption, particularly due to migrating leukocytes in ischemia. These hypotheses will be examined in five specific aims: 1+2) Determine whether upregulation of system xc- by stroke-related factors, inflammatory mediators or sulforaphane is protective. 3+4) Determine whether Nrf2 is activated in the cerebral endothelium after stroke or inflammation and whether its activation and the upregulation of downstream proteins will protect the cerebral endothelium. 5) Examines whether treatment with sulforaphane can protect the BBB in vivo. These specific aims will be examined in vitro, to allow elucidation of molecular mechanisms, and in vivo, to determine pathophysiological relevance. The results should highlight endogenous BBB protective mechanisms and the potential exogenous compounds to activate or inhibit those mechanisms. PUBLIC HEALTH RELEVANCE: Brain blood vessels have very specialized functions, forming a blood-brain barrier. Disuption of that barrier occurs in many neurological disorders and injuries, contributing to brain dysfunction. This proposal examines natural defense mechanisms that may protect the blood-brain barrier, how to activate those mechanisms or prevent their inactivation therapeutically.