Interferon beta modulates neuroinflammation and extends tPA therapeutic window in ischemic stroke

项目总结 中风是导致死亡的主要原因，在多达30%的幸存者中会导致永久性残疾。其中， 缺血性中风约占所有病例的87%。组织纤溶酶原激活物(TPA)是唯一的 有效治疗缺血性中风，但治疗窗口非常有限，为3-4.5小时。令人不快地被耽搁了 TPA治疗超过发病3-4.5小时会增加血脑屏障(BBB)破坏的风险，并 出血性转化(HT)，进一步加重脑损伤。此外，tPA已被证明可以 通过增强小胶质细胞(MG)的激活而加重神经炎症。因此，迫切需要制定一种 减轻脑缺血后炎症和拓宽tPA治疗窗的治疗方法 卒中。干扰素β是一种具有免疫调节特性的细胞因子，已被美国食品和药物管理局批准用于 治疗复发-缓解型多发性硬化症(MS)超过十年。已经有充分的证据表明 干扰素β可抑制多发性硬化患者中枢神经系统炎症，提示干扰素β可能具有治疗多发性硬化症的作用。 缺血性中风的治疗。事实上，我们最近的发现表明，干扰素β可以减轻缺血诱导的作用。 在啮齿动物卒中模型中脑梗塞和神经功能障碍的减轻，从而证明干扰素β具有 对缺血性中风有保护作用。然而，涉及到保护作用的详细机制 干扰素β抑制缺血诱导的原发和再灌流诱导的继发性神经炎症 仍有待阐明。更重要的是，干扰素β对组织型纤溶酶原激活剂介导的神经炎症和延迟性炎症的影响 TPA诱导的缺血脑内血脑屏障破坏和羟色胺尚不清楚。我们假设干扰素β可以改善 缺血、再灌注和tPA诱导的炎性MG转化为抗炎性MG所致的缺血性脑损伤 炎症性MG和调节炎性免疫细胞浸润。此外，干扰素β延长了tPA。 通过抑制延迟性tPA诱导的MMP3/9的产生、血脑屏障的破坏和高血压的治疗窗口 脑缺血。我们提出了以下三个具体目标来检验我们的假设。在目标1中，我们将测试 干扰素β与组织型纤溶酶原激活剂合用对缺血性脑损伤及组织型纤溶酶原激活剂治疗窗的影响 卒中。在目标2中，我们将确定干扰素β与tPA联合应用对急性发作时MG激活的影响。 缺血性卒中亚急性期对炎性免疫细胞的影响。在AIM 3，我们将确定干扰素β是否能减轻缺血性卒中患者tPA诱导的迟发性血脑屏障破坏和羟色胺。 我们建议的研究的完成将提供强有力的证据，证明干扰素β可以被开发为一种新型的 治疗缺血性中风，并最终导致一个新的医疗干预场所的脑缺血。

PROJECT SUMMARY Stroke is a leading cause of death and results in permanent disability in up to 30% of survivors. Among them, ischemic stroke accounts for about 87 percent of all cases. Tissue plasminogen activator (tPA) is the only effective treatment for ischemic stroke but has a very limited therapeutic window of 3-4.5h. Undesirably, delayed tPA treatment beyond 3-4.5h disease onset increases risk of blood brain barrier (BBB) disruption and hemorrhagic transformation (HT) that further exacerbates brain injury. In addition, tPA has been shown to aggravate neuroinflammation by enhancing microglia (MG) activation. Thus, there is a critical need to develop a therapeutic approach to attenuate brain inflammation and widen the tPA therapeutic window following ischemic stroke. Interferon beta (IFNβ), a cytokine with immunomodulatory properties, was approved by the FDA for the treatment of relapsing-remitting multiple sclerosis (MS) for more than a decade. It has been well-established that IFNβ suppresses CNS inflammation in MS, thereby suggesting that IFNβ might have a therapeutic potential for the treatment of ischemic stroke. Indeed, our recent findings showed that IFNβ attenuated ischemia-induced brain infarct and lessened neurological deficits in rodent stroke models, thereby demonstrating that IFNβ confers a protective effect against ischemic stroke. However, detailed mechanisms involved in the protective effects of IFNβ on the suppression of ischemia-induced primary and reperfusion-mediated secondary neuroinflammation remain to be elucidated. More importantly, the effect of IFNβ on tPA-mediated neuroinflammation and delayed tPA-induced BBB disruption and HT in the ischemic brain is unknown. We hypothesize that IFNβ ameliorate ischemic brain injury by converting ischemia, reperfusion, and tPA-induced inflammatory MG into anti- inflammatory MG and modulating inflammatory immune cell infiltration. In addition, IFNβ extends the tPA therapeutic window by inhibiting delayed tPA-induced MMP3/9 production, BBB disruption, and HT in the ischemic brain. We propose the following three specific aims to test our hypothesis. In Aim 1, we will test the effect of IFNβ, co-administered with tPA, on ischemic brain injury and on the tPA therapeutic window in ischemic stroke. In Aim 2, we will determine the effect of IFNβ, co-administered with tPA, on MG activation during acute phase and on infiltrating inflammatory immune cell activation during sub-acute phase in ischemic stroke. In Aim 3, we will determine whether IFNβ alleviates delayed tPA-induced BBB disruption and HT in ischemic stroke. The completion of our proposed studies will provide strong evidence that IFNβ can be developed as a novel therapy for ischemic stroke and ultimately lead to a new venue of medical intervention for cerebral ischemia.