The role of NADPH oxidases in Multiple Sclerosis and its animal model, the experimental autoimmune encephalomyelitis

异常的免疫反应是中枢神经系统(CNS)自身免疫的根本原因，导致炎性损害，脱髓鞘，轴突变性和神经元丢失。尤其是神经变性似乎对多发性硬化症(MS)等慢性炎症性脱髓鞘疾病患者的不可逆转缺陷具有决定性作用，因此迫切需要创新的策略来防止神经元丢失。一种这样的高电位途径可能是反应性氧化物种(ROS)的出现，这些ROS已知在神经炎症中导致组织损伤和神经元死亡。然而，所有通过应用抗氧化剂化合物来清除ROS的主要临床试验都没有产生临床益处。抗氧化剂缺乏效果的一个原因可能是，在ROS水平升高的地方，抗氧化剂的生物利用度太低，因为氧化应激不是系统性的，而是局部的现象。鉴于此，迫切需要鉴定和表征与疾病相关的氧化应激源，以便通过首先防止ROS的形成来实现氧化应激的特定治疗靶点，而不是在ROS形成后在全身清除ROS。ROS的潜在来源是NADPH氧化酶(NOX)，这是已知的唯一专门产生ROS的酶家族。到目前为止，已经鉴定出五种不同的亚型。NOX1、NOX2、NOX4和NOX5在脑内均有表达，因此这些亚型可能在炎症加重、血脑屏障破坏和/或神经炎性变性中起决定性作用。然而，它们的作用、功能影响、背后的机制以及它们在体内参与中枢神经系统自身免疫的机制尚不清楚，因此，我们将评估NOX在体外和体内的功能相关性。为了阐明它们的作用，我们将在不同NOX缺乏的动物中诱导MS的动物模型，并与野生型对照进行比较。为了阐明作用模式，我们将分析不同的可能途径，并使用组织学、免疫学和分子生物学技术对这些动物进行表征。在解开机制后，我们将使用不同的可用的抑制剂来测试NOX的调节是否在MS动物模型中作为治疗有效。最后，我们将通过分析多发性硬化症患者的血液、脑脊液样本和中枢神经系统组织来评估氮氧化物在人类中的相关性。综上所述，该项目提供了一个独特的机会来阐明氧化应激在神经炎症中的功能作用和参与，因此可能成为未来改善炎性脱髓鞘疾病(如多发性硬化症)的治疗策略。

Aberrant immune responses represent the underlying cause of central nervous system (CNS) autoimmunity, leading to inflammatory lesions with demyelination, axonal degeneration and neuronal loss. As especially neurodegeneration seems to be decisive for irreversible deficits of individuals with chronic inflammatory demyelinating disorders like multiple sclerosis (MS), innovative strategies to prevent neuronal loss are urgently needed. One such high-potential pathway may be the occurrence of reactive oxidative species (ROS) that are known to cause tissue damage and neuronal death in neuroinflammation. However, all major clinical trials to scavenge ROS by applying antioxidant compounds did not result in clinical benefit. One reason for the lack of effect of anti-oxidants might be that their bioavailability is too low in those locations where ROS levels are elevated, as oxidative stress is not a systemic but local phenomenon. On this account, identification and characterization of the disease-relevant enzymatic sources of oxidative stress is urgently needed to allow specific therapeutic targeting of oxidative stress by preventing the formation of ROS in the first place, instead of scavenging ROS in the entire body after they have been formed. Potential sources of ROS are NADPH oxidases (NOX), the only known enzyme family that is especially dedicated to ROS production. Five different isoforms have been identified so far. NOX1, NOX2, NOX4 and NOX5 are expressed in brain, so that these isoforms might be decisive for enhanced inflammation, blood brain barrier breakdown and/or neurodegeneration in neuroinflammation. However, their role, functional impact, the mechanism behind and therefore their participation in terms of CNS autoimmunity in vivo is not yet understood.Therefore, we will assess the functional relevance of NOX in vitro and in vivo. To clarify their role, we will induce an animal model of MS in different NOX-deficient animals in comparison to wildtype controls. To clarify the mode of action, we will analyse different possible pathways and characterize these animals using histological, immunological and molecular biological techniques. After unraveling the mechanism, we will test if the modulation of NOX is effective as therapy in an animal model of MS using different available inhibitors. Finally, we will assess the relevance of NOX also in humans by analyzing blood, cerebrospinal fluid samples and CNS tissue of individuals with MS.In summary, this project offers the unique chance to clarify the functional role and participation of oxidative stress in neuroinflammation and might therefore serve as a future therapeutical strategy to ameliorate inflammatory demyelinating disorders such as MS.