Non-canonical translation in hippocampal mGluR-dependent long-term depression - R

描述(申请人提供)：突触可塑性描述突触连接的特定修改，以响应神经元的经验，并被广泛认为是记忆的细胞基质。大量研究表明，从头合成蛋白对于稳定持久形式的突触可塑性是必不可少的，如长时程增强(LTP)和长期抑制(LTD)。然而，神经元中有两种翻译模式可以促进这些过程中的蛋白质合成。更常见和研究较多的模式是规范或帽子依赖的翻译，当翻译起始因子的多蛋白复合体与真核mRNAs的5‘端结合时启动。蛋白质合成也可以通过一条非规范的途径发生，该途径与mRNA中的内部核糖体进入位点(IRES)中的一组不同的因子一起启动翻译。关于这一非规范途径在神经元正常生理活动中的作用，人们知之甚少。然而，以前的工作和我们实验室的新的初步数据表明，这一翻译途径可能在突触可塑性的持久形式中发挥作用。这项研究的目的是了解非规范翻译是如何参与由海马区代谢性谷氨酸受体(MGluR)介导的依赖蛋白质合成的LTD的。我将使用有针对性的病毒和药物操作与报告活性分析、图像分析和蛋白质组学相结合的方法来测试中心假设，即非规范翻译被积极利用来支持海马区的mGluR-LTD。其具体目的是描述非规范翻译是如何在时间和空间上受海马mGluR-Ltd.调控的。这项工作具有重要意义，因为它通过洞察非规范的翻译机制，解决了我们在突触可塑性过程中对蛋白质合成的活性依赖调节方面的一个主要知识空白。更好地了解突触可塑性背后的神经生物学事件 这可能有助于开发新的药物或策略来改善记忆功能或削弱记忆，这具有重要的临床意义。

DESCRIPTION (provided by applicant): Synaptic plasticity describes the specific modification of synaptic connections in response to neuronal experience and is widely held as a cellular substrate of memory. Numerous studies have demonstrated that de novo protein synthesis is essential for stabilizing persistent forms of synaptic plasticity such as long-term potentiation (LTP) and long-term depression (LTD). However, there are two modes of translation in neurons that can contribute to the protein synthesis underlying these processes. The more common and well-studied mode is canonical or cap-dependent translation, which initiates when a multi-protein complex of translation initiation factors bind the 5' cap of eukaryotic mRNAs. Protein synthesis can also occur through a non- canonical pathway that initiates translation with a different set of factors from an internal ribosome entry site (IRES) in the mRNA. Very little is known about the role of this non-canonical pathway during normal physiological activity in neurons. However, previous work and new preliminary data from our lab suggests that this translation pathway may play a role in persistent forms of synaptic plasticity. The goal of the proposed research is to understand how non-canonical translation is involved specifically in a protein synthesis- dependent form of LTD mediated by metabotropic glutamate receptors (mGluR) in the hippocampus. I will use a combination of targeted viral and pharmacological manipulations with reporter activity assays, image analysis and proteomics to test the central hypothesis that non-canonical translation is actively utilized to support mGluR-LTD in the hippocampus. The specific aim is to characterize how non-canonical translation is temporally and spatially regulated following hippocampal mGluR-LTD. This work is significant because it addresses a major gap in our knowledge about activity-dependent regulation of protein synthesis during synaptic plasticity by providing insight into non-canonical mechanisms of translation. A better understanding of the neurobiological events that underlie synaptic plasticity will likely aid the development of new agents or strategies for improving memory function or weakening memories, which has important clinical implications.