Interleukin-33 as an immune therapy for stroke

中风是美国退伍军人的主要医疗问题之一。经典的神经中枢 中风研究中对大脑的看法可能阻碍了有效治疗方法的发展。白质 (WM)损伤，其特征是髓鞘丢失和产生髓鞘的少突胶质细胞(OLs)，是导致 中风后的功能性残疾，但直到最近才得到广泛的重视。有能力的战略 减轻灰质和西医的病理生理学需要达到完全的脑保护和长期的 神经恢复。越来越多的证据表明，不同功能表型的小胶质细胞/ 巨噬细胞在脑损伤后炎症状态的调节中起着重要作用，最终 影响大脑的完整性。具体地说，M2样表型对于组织保存和脑修复是必不可少的 因为M2细胞可以消除局部炎症，清除细胞碎片，并提供保护因子。 白介素33(IL-33)是一种多功能细胞因子，参与多种免疫反应， 包括增强巨噬细胞的M2样反应。有趣的是，IL-33及其受体 由ST2和IL-1受体辅助蛋白组成，均在中枢神经系统表达。IL-33/ST2的确切作用 然而，缺血脑中的信号并不是很好的特征和潜在的作用机制。 仍然不为人所知。我们的初步结果表明，ST2基因敲除(KO)小鼠表现出扩大的脑梗塞， 短暂性大脑中动脉闭塞(TMCAO)后WM损伤加重，感觉运动功能障碍加重。 相反，tMCAO后1h鼻腔内注射IL-33可减轻脑梗塞。值得注意的是，ST2 KO小鼠 显示缺血时M2样标记物表达减少，而M1样标记物表达增加 大脑。我们在体外发现IL-33增强M2极化，尤其是IL-10的产生。 小胶质细胞。此外，IL-33治疗提高了神经元和OL在缺氧缺糖条件下的存活率 (OGD)，IL-10中和抗体可消除这种作用。 本研究将进一步探讨IL-33/ST2信号通路对缺血性脑损伤的保护作用。 希望将IL-33发展为一种新的、临床可行的治疗策略来改善中风后的脑功能 损坏。我们将测试主要的假设，即IL-33/ST2信号的激活可以预防 脑缺血通过增强小胶质细胞/巨噬细胞向保护性M2表型的极化，这是 进而限制中风后神经元和WM的损伤。要测试的具体目标是：目标1：测试 IL-33治疗后对幼年和老年小鼠局灶性脑缺血具有保护作用的假说。目标 2：验证IL-33/ST2信号通过移位改善缺血性神经元和OL损伤的假设 小胶质细胞向保护性表型转变。目的3：检验IL-10是一种基本保护因子的假设 由IL-33处理的小胶质细胞释放。这项研究的成功将阐明IL-33作为一种潜在的治疗手段 卒中后灰质和西医保护和长期康复的策略。

Stroke is one of the major medical concerns for United States military veterans. The classically neurocentric view of the brain in stroke research may have hindered the development of effective therapies. White matter (WM) injury, characterized by loss of myelin and myelin-producing oligodendrocytes (OLs), is a major cause of functional disability after stroke but has not been widely appreciated until recently. Strategies that are able to alleviate both gray matter and WM pathophysiology are needed to achieve full brain protection and long-term neurological recovery. Accumulating evidence suggests that the different functional phenotypes of microglia/ macrophages contribute considerably to the regulation of inflammatory status of injured brain and ultimately impact the brain integrity. Specifically, M2-like phenotype is essential for tissue preservation and brain repair because M2 cells resolve local inflammation, clear cell debris, and provide protective factors. Interleukin-33 (IL-33) is a multifunctional cytokine that involves in a wide range of immune responses, including potentiating M2-like responses in macrophages. Interestingly, both IL-33 and its receptor, which consists of ST2 and IL-1 receptor accessory protein, are expressed in the CNS. The precise roles of IL-33/ST2 signaling in the ischemic brain, however, are not well-characterized and the underlying mechanisms of action remain unknown. Our preliminary results show that ST2 knockout (KO) mice exhibited enlarged brain infarct, deteriorated WM injury and worse sensorimotor deficits after transient middle cerebral artery occlusion (tMCAO). In contrast, intranasal infusion of IL-33 1h after tMCAO attenuates brain infarct. Remarkably, ST2 KO mice showed reduced expression of M2-like markers and increased expression of M1-like markers in the ischemic brain. We have found in vitro that IL-33 potentiates M2 polarization, especially IL-10 production in primary microglia. Furthermore, IL-33 treatment enhanced neuronal and OL survival against oxygen glucose deprivation (OGD) in neuron-glia mixed culture, which can be abolished by IL-10 neutralizing antibody. This proposal will further explore the protective effect of IL-33/ST2 signaling after ischemic brain injury with the hope of developing IL-33 into a novel, clinically feasible therapeutic strategy to ameliorate post-stroke brain damage. We will test the overarching hypothesis that the activation of IL-33/ST2 signaling protects against cerebral ischemia by enhancing microglia/macrophage polarization toward a protective M2 phenotype, which in turn restricting neuronal and WM injury after stroke. The Specific Aims to be tested are: Aim 1: Test the hypothesis that IL-33 post-treatment protects against focal cerebral ischemia in both young and aged mice. Aim 2: Test the hypothesis that IL-33/ST2 signaling ameliorates ischemic neuronal and OL damage via shifting microglia toward a protective phenotype. Aim 3: Test the hypothesis that IL-10 is an essential protective factor released by IL-33-treated microglia. The success of this study will shed light on IL-33 as a potential therapeutic strategy for both gray matter and WM protection and long-term recovery after stroke.