Defining the epitope in antiNMDA receptor encephalitis

描述（申请人提供）：谷氨酸是中枢神经系统中的主要兴奋性递质，不仅对突触传递至关重要，而且对突触可塑性和基因表达控制等长期神经元变化也至关重要。然而，谷氨酸的过度释放（如在病理情况下发生的）可导致细胞死亡，并且NMDA受体功能减退与精神分裂症有关。最近，与Josep Dalmau博士合作，我们发现NMDA受体的抗体介导与人格和行为变化，急性精神病和短期记忆缺陷相关的免疫性脑炎。患有这种综合征的个体会产生抗体，选择性地与海马体反应，海马体是一个与记忆有关的区域，抗原是NMDAR的NR 1亚基。使用分子生物学方法，我们已经将表位定义为NR 1上的前380个氨基酸内。此外，表位的产生被衣霉素阻断，并且NR 1中特异性N-连接的糖基化/脱酰胺位点的破坏消除了免疫反应性，表明位点特异性N-连接的糖基化和脱酰胺化特异性地参与表位的产生。我们将表征该表位的特征，以便更好地理解这2个关键生化过程在NMDAR特性中的作用。我们将确定大脑中脱酰胺和差异糖基化NMDA受体的分布，并将其与抗NMDA受体脑炎中发现的患者相关抗NMDAR免疫反应性的独特模式进行比较。此外，我们将用患者血清免疫标记NMDAR，并评估标记的NMDAR是否在特定位点糖基化或脱酰胺。在我们的第二个目标中，我们将NMDA受体引入缺乏特异性糖基化酶的细胞系中。然后，我们将评估对NMDAR的糖基化模式、其细胞运输及其生理特性的影响。这些将与特定脑区域和细胞类型中NMDAR的独特特性进行比较。总之，这些目标将提供有关抗NMDAR脑炎机制的新数据，对糖基化和脱酰胺化在神经元化学中的作用提供新的理解，并为研究NMDA的生物化学设计新的策略。公共卫生相关性：该提案涉及在称为抗N-甲基-D-天冬氨酸受体脑炎的疾病中产生抗体的机制。通过对这一过程的理解，该提案可能有助于预防这种疾病损害的治疗，并有助于对其他神经系统疾病（如中风）的基本了解。

DESCRIPTION (provided by applicant): Glutamate, the major excitatory transmitter in the central nervous system, is crucial not only for synaptic transmission but also for long-term neuronal changes such as synaptic plasticity and control of gene expression. However, excessive release of glutamate (as occurs in pathological situations) can result in cell death and NMDA receptor hypofunction has been implicated in schizophrenia. Recently, in collaboration with Dr. Josep Dalmau, we have found that antibodies to the NMDA receptor mediate an immune encephalitis associated with personality and behavioral changes, acute psychosis, and short-term memory deficits. Individuals with this syndrome make antibodies that selectively react with the hippocampus, an area involved in memory, and the antigen is the NR1 subunit of the NMDAR. Using molecular biological approaches we have defined the epitope to be within the first 380 amino acids on NR1. Furthermore, creation of the epitope is blocked by tunicamycin and disruption of a specific N- linked glycosylation/deamidation site in NR1 removes immunoreactivity, suggesting that site specific N-linked glycosylation and deamidation are specifically involved in the production of the epitope. We will characterize the features of this epitope in order to better understand the role of these 2 crucial biochemical processes in NMDAR properties. We will ascertain the distribution of deamidated and differentially glycosylated NMDA receptors in the brain and comparing this to the unique pattern of patients' related anti-NMDAR immunoreactivity that is found in anti NMDA receptor encephalitis. In addition, we will immunolabel NMDAR with patient serum and assess whether labeled NMDAR are glycosylated or deamidated at specific sites. In our second aim, we introduce NMDA receptors into cell lines lacking specific glycosylation enzymes. We will then assess the effect on the glycosylation pattern of NMDAR, on their cellular trafficking, and their physiological properties. These will be compared to the unique properties of NMDAR in specific brain regions and cell types. Together, these aims will supply new data on the mechanisms involved in antiNMDAR encephalitis, provide new understanding of the role of glycosylation and deamidation in neuronal chemistry, and devise new strategies for studying the biochemistry of NMDA. PUBLIC HEALTH RELEVANCE: The proposal addresses the mechanisms by which antibodies are generated in the disorder known as anti-N-methyl-D-aspartate Receptor encephalitis. Through understanding of this process, the proposal may facilitate therapies for preventing damage in this disorder and a basic understanding of other neurologic disorders such as stroke.