免疫蛋白酶体调控NF-κB与Wnt/β-catenin通路介导脑缺血再灌注血脑屏障损伤的作用机制研究

脑缺血后血脑屏障（BBB）损伤机制复杂，缺血过度激活NF-κB通路损伤BBB；而缺血抑制Wnt/β-catenin通路影响了BBB修复。泛素-蛋白酶体系统（UPS）在调控NF-κB和Wnt/β-catenin通路活化起关键作用，且参与了脑缺血损伤过程。我们前期研究发现大鼠脑缺血/再灌注（MCAO/R）后脑免疫蛋白酶体（IP）作为UPS的负性成分介导缺血再灌注损伤；抑制IP有脑保护作用，相关机制尚不明确。为此我们提出假说：免疫蛋白酶体调控NF-κB与Wnt/β-catenin通路介导脑缺血再灌注血脑屏障损伤。为验证本假说，我们选择大鼠MCAO/R模型和原代大鼠脑微血管内皮细胞与星形胶质细胞共培养的体外BBB氧糖剥夺/复供模型，利用组织病理、western blot 和RNA 干扰等技术，探讨IP在脑缺血BBB损伤中的作用及其机制，为IP作为急性脑梗死的治疗靶点提供重要的理论和实验依据。

The mechanism underlying blood–brain barrier (BBB) disruption after cerebral ischaemic/reperfusion(I/R) injury is complex and poorly understood. Ischemia-induced excessive activation of nuclear transcription factor kappaB (NF-κB) leads to impairment of BBB; however, the activation of Wnt/β-catenin signaling pathway which contributes to BBB repairmen is inhibited after cerebral ischemia. Ubiquitin proteasome system (UPS) plays a critical role in regulating the activation of NF-κB and Wnt/β-catenin pathway, and involves in cerebral ischemia injury. Immunoproteasome (IP) is one of the important ingredients of UPS. In our previous study, we firstly discovered that the augmentation of expression and proteasome-dependent proteolytic activities of immunoproteasome as one of negative components of UPS mediated ischemia-reperfusion injury. Furthermore, we confirmed that selective inhibition of the immunoproteasome subunit offered a strong neuroprotection after MCAO. Nevertheless, the underlying mechanisms remain to be determined.Our current hypothesis is that effects and mechanisms of immunoproteasome on the cerebral ischemia/reperfusion-induced blood brain barrier injury by regulating NF-κB and Wnt/β-catenin signaling pathway. To illustrate this hypothesis, we will use a rat model of MCAO/R and in vitro BBB model composed of co-cultivation of primary rat brain microvascular endothelial cells (BMVECs) with astrocytes that were pretreatment by oxygen glucose deprivation/reoxygenation(OGD/R). We will firstly determine the effects of immunoproteasome on the BBB after cerebral ischemia reperfusion, and further investigate the underlying mechanisms by means of histochemistry, western blot and RNA interference and so on. This study will provide important theoretical and experimental evidences of immunoproteasome as one of targets in the treatment of acute cerebral infarction.