Gliovascular Mechanisms of Blood-Brain Barrier Disruption in Neuroinflammatory Disease

摘要 多发性硬化症(MS)是一种范围广泛的中枢神经系统(CNS)衰弱性神经炎症性疾病 神经症状，如麻木、瘫痪和失明。疾病病理表现为大量 炎症脱髓鞘导致轴突损伤的血管周围病变，是神经元丢失的主要罪魁祸首 多发性硬化症患者的功能。虽然关于细胞和分子与疾病病理有关的知识很多，但什么细胞 而启动针对中枢神经系统的免疫级联反应的分子机制尚不清楚。最早的迹象是 人类多发性硬化症患者和多发性硬化症动物模型的损害都是血脑屏障(BBB)的破坏和激活 小胶质细胞，这是中枢神经系统的常驻免疫细胞。我们之前的活体成像研究发现，小胶质细胞是 实验性自身免疫性脑脊髓炎(EAE，已建立的多发性硬化症动物模型)中最早的应答者。我们发现 小胶质细胞聚集在血管周围，这些血管将血液因子泄漏到中枢神经系统，从而确定血管周围的位置 在那里形成新的损伤。是什么导致早期血管改变，局部血管破裂，并招募 形成这些血管周围病变的外周免疫细胞尚不清楚。在这个提案中，我们将探索蜂窝和 EAE和MS早期血管改变和血脑屏障破坏的分子机制我们将进行调查 EAE早期血管周围小胶质细胞聚集是否涉及小胶质细胞和血管壁之间的信号传递， 导致这样的血管改变，并推动免疫细胞向中枢神经系统募集。具体来说，我们将确定是否 激活的小胶质细胞通过内皮素(ET)与脑血管细胞成分进行通讯。 这是调节血管张力、血压和血压的主要分子机制之一。 血液流动。除了改变血管特性外，ET-1还具有强大的促炎作用，因为它增强了反式-血管紧张素转换酶。 单核细胞和白细胞的内皮细胞通道。ET信号与心血管疾病有关，例如 高血压和中风，但对其在多发性硬化症及其动物模型中的潜在作用知之甚少。我们的初步结果和 先前的研究表明，ET系统是导致脑血流量和血管减少的一个很好的候选途径 EAE和MS的异常我们建议的实验方法结合了药物和基因抑制 小鼠血管破裂及小胶质细胞、巨噬细胞和T细胞的体内成像方法 当然是EAE。此外，我们将寻求验证我们在临床前动物模型中关于ET途径表达的结果 多发性硬化症患者的不同类型的病变，使用我们在 克利夫兰诊所。由于ET受体拮抗剂是FDA批准用于治疗高血压的，我们的研究有 有可能提供原则证明，证明重新调整这些药物的用途可能对治疗多发性硬化症有利 人类病人。

Abstract Multiple sclerosis (MS) is a debilitating neuroinflammatory disease of the central nervous system (CNS) with a broad range of neurological manifestations such as numbness, paralysis, and loss of vision. Disease pathology presents with massive perivascular lesions where inflammatory demyelination results in axonal damage, the main culprit for the loss of neuronal function in MS patients. Although a lot is known about cells and molecules involved with disease pathology, what cellular and molecular mechanisms initiate the immunological cascade against the CNS remain unknown. The earliest signs of lesions in both human MS patients and in animal models of MS are blood-brain barrier (BBB) disruption and activation of microglia, which are the resident immune cells of the CNS. Our previous in vivo imaging studies identified microglia as the earliest responders in experimental autoimmune encephalomyelitis (EAE, an established animal model for MS). We found that microglia cluster around vessels that leak blood factors into the CNS and thereby determine the perivascular locations where new lesions form. What causes early vascular alterations, local disruption of blood vessels, and recruitment of peripheral immune cells that form these perivascular lesions is not known. In this proposal, we will explore the cellular and molecular mechanisms involved with early vascular alterations and BBB disruption in EAE and MS. We will investigate whether early perivascular microglial accumulation in EAE involves signaling between microglia and the vessel wall, which causes such vascular alterations and drives immune cell recruitment to the CNS. Specifically, we will determine whether activated microglia communicate with the cellular constituents of the cerebral vasculature through the endothelin (ET) system, which is one of the main molecular mechanisms involved in the regulation of vascular tone, blood pressure, and blood flow. Besides altering vascular properties, ET-1 also has potent pro-inflammatory effects as it enhances trans- endothelial passage of monocytes and leukocytes. ET signaling has been implicated in cardiovascular diseases, such as hypertension and stroke, but little is known about its potential role in MS or its animal models. Our preliminary results and prior studies suggest that the ET system is a good candidate pathway for inducing reduced cerebral blood flow and vascular abnormalities in EAE and MS. Our proposed experimental approach combines pharmacological and genetic inhibition approaches with in vivo imaging of vascular disruption and microglia, macrophages, and T cells in mice undergoing the course of EAE. Moreover, we will seek to validate our preclinical animal model findings on ET pathway expression across different types of lesions from MS patients by using the unique human brain tissue bank that we have available at the Cleveland Clinic. Since ET receptor antagonists are FDA-approved for the treatment of hypertension, our studies have the potential to provide proof-of-principle validation that repurposing these drugs can be beneficial for the treatment of MS in human patients.