Synapse Remodeling and Neuronal MHC Class I

描述（由申请人提供）：本研究的长期目标是了解大脑发育过程中，由神经回路的活动驱动功能介导的经验如何转化为突触连通性的持久结构变化。本研究计划的具体目标是检验发育中活动依赖性突触重塑和成人突触可塑性的假设，涉及一个在免疫系统中具有众所周知功能的大基因家族：MHC I类基因（人类HLA基因）。在无偏倚的基于pcr的神经活动调节基因差异筛选中意外地发现了神经元MHC I类mRNA的表达；在缺乏MHC I功能的小鼠中进行的初步遗传研究随后揭示了视觉系统发育和海马可塑性需要I类MHC （Huh et al, 2000）。本文提出的研究目标是更多地了解I类MHC在正常、未受伤的中枢神经系统中的功能。提出了三个具体目标。1)通过免疫组织化学、特异脑区RT-PCR、原位杂交检测CNS表达，确定神经元中MHCI类蛋白是否位于突触，MHCI家族成员的表达模式是否存在分子逻辑。2)通过标准微电极记录和对野生型、功能缺失（B2m/TAP1）和功能获得（NSE-Db）突变小鼠海马切片谷氨酸受体运输的生化评估，确定MHC I类在海马双向突触可塑性中的作用。3)通过在体外检测野生型和突变型海马神经元突触的结构和生理，在改变神经活动的药理学操作后，确定I类MHC对神经活动转化为突触持久解剖变化是否必要。这些实验的结果应该拓宽我们对在发育和成人中使用依赖性变化是如何在神经回路结构中编码的理解。突触和神经回路的变化发生在儿童时期学习的关键时期，以及一生中记忆形成的关键时期。了解相关的分子和机制对于解决并最终治愈学习和记忆障碍也至关重要，从阅读障碍、自闭症和其他学习障碍，到阿尔茨海默氏症和其他大脑老化的记忆障碍。

DESCRIPTION (provided by applicant): The long term goal of this research is to learn how experience during brain development, mediated by the activity-driven functioning of neural circuits, is translated into lasting structural change in synaptic connectivity. The specific goal of this research proposal is to examine the hypothesis that activity-dependent synaptic remodeling in development, and adult synaptic plasticity, involve a large gene family with well-known function in the immune system: MHC Class I genes (HLA genes in humans). Neuronal MHC Class I mRNA expression was discovered unexpectedly in an unbiased PCR-based differential screen for genes regulated by neural activity; initial genetic studies in mice lacking MHC I function then revealed a requirement for Class I MHC in visual system development and hippocampal plasticity (Huh et al, 2000). The goal of research proposed here is to learn more about how Class I MHC functions in the normal, uninjured CNS. Three specific aims are proposed. 1) Determine whether MHC Class I protein in neurons is located at synapses and whether there is a molecular logic to expression patterns of MHCI family members by means of immunohistochemistry, RT-PCR of specific brain regions, and in situ hybridization to examine CNS expression. 2) Determine how MHC Class I functions in bidirectional synaptic plasticity in the hippocampus by standard microelectrode recordings and biochemical assessment of glutamate receptor trafficking in hippocampal slices from wildtype, loss (B2m/TAP1) and gain of function (NSE-Db) mutant mice. 3) Determine if Class I MHC is necessary for the translation of neural activity into lasting anatomical change at synapses by examining structure and physiology of synapses in wild type and mutant hippocampal neurons in vitro following pharmacological manipulations that alter neural activity. The results of these experiments should broaden our understanding of how use-dependent changes, both in development and in adult, are encoded in the structure of neural circuits. Changes in synapses and circuits occur during critical periods of learning in childhood, as well as in memory formation throughout life. Understanding the molecules and mechanisms involved is also crucial for addressing and ultimately curing disorders of learning and memory, from Dyslexia, Autism and other learning disorders, to Alzheimer's and other memory disorders of the aging brain.