Effectors of presynaptic cAMP dependent potentiation at mossy fiber synapses

苔藓纤维突触突触前 cAMP 依赖性增强的效应器

• 批准号: 10501884
• 负责人: Anis Contractor
• 金额: $ 63.84万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2027-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10501884
• 关键词: Affect; Aging; Alzheimer' s Disease; Anatomy; Animals; Anxiety Disorders; Behavioral; Biochemical; Brain; Chemosensitization; Coupling; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Dense Core Vesicle; Electrophysiology (science); Environment; Episodic memory; Event; Exocytosis; Goals; Heart; Hippocampus (Brain); Impairment; In Situ; In Vitro; Knock-out; Label; Learning; Mammals; Mediating; Memory; Memory impairment; Microscopy; Molecular; Mus; Neurodegenerative Disorders; Neurons; Neuropeptides; Pattern; Pharmacology; Phosphorylation; Physiological; Physiology; Play; Process; Proteins; Proteomics; Research; Resolution; Retrieval; Role; Schizophrenia; Signal Pathway; Signal Transduction; Structure; Synapses; Synaptic Transmission; Synaptic Vesicles; Synaptic plasticity; Testing; Vesicle; Visit; dentate gyrus; experience; hippocampal pyramidal neuron; insight; memory process; memory retrieval; mossy fiber; nanoenvironment; nervous system disorder; neural circuit; neuropsychiatric disorder; neurotransmitter release; postsynaptic; presynaptic; social; synaptic function; way finding

SUMMARY Synaptic plasticity in the hippocampus is critical to the formation, storage and retrieval of episodic memories. The separate regions of the hippocampus have evolved to play distinct roles in spatial navigation, contextual memories, social memories, and our ability to separate patterns or complete patterns to reconstruct partial memories. In particular the dentate and CA3 regions of the hippocampus are involved in pattern separation that is vital to the integrity of episodic memories. At the center of this region are the mossy fiber afferents that make conditional detonator synapses onto CA3 pyramidal neurons, which have a distinct form of presynaptic cAMP dependent plasticity. Despite the importance of cAMP plasticity to memory formation and retrieval in the CA3 the exact molecular mechanisms underlying MF LTP have yet to be uncovered. The premise of this research builds upon our finding that there are at least two downstream cAMP effectors, PKA (protein kinase A) and Epac2 (exchange protein directly activated by cAMP 2), that contribute to cAMP dependent MF LTP. Despite these findings it is still not known how signaling by each of these effectors results in elevated release from MF synapses and, what are the important targets and substrates that are involved in MF LTP. Here we will use a comprehensive approach with leading edge proteomic, biochemical and electrophysiological approaches to determine the signaling partners of the cAMP effectors, and uncover the physiological mechanism of their actions. Thus, in Aim 1 we will take orthogonal approaches to find the interactors and substrates of PKA and Epac2 and validate these by performing high resolution labeling in situ. In Aim 2 we will determine the exact physiological mechanism that underlie increases in release of neurotransmitter at MF synapses using a combined optoactivation-knockout/pharmacological strategy. In the final Aim we will answer the question of how these different, but convergent, mechanisms are engaged during naturalistic activity patterns, and whether selective disruption of these effectors impairs the ability of mice to separate similar patterns that underlie the formation and retrieval of episodic memories.

概括 海马体的突触可塑性对于情景记忆的形成、存储和检索至关重要。 海马体的不同区域已经进化出在空间导航、情境导航等方面发挥着不同的作用。 记忆、社会记忆以及我们分离模式或完整模式以重建部分模式的能力 回忆。特别是海马体的齿状区和 CA3 区参与模式分离 这对于情景记忆的完整性至关重要。该区域的中心是苔藓纤维传入 将条件雷管突触置于 CA3 锥体神经元上，该神经元具有独特的突触前形式 cAMP 依赖性可塑性。尽管 cAMP 可塑性对于记忆形成和检索非常重要 CA3 MF LTP 的确切分子机制尚未被揭示。这样做的前提是 研究建立在我们发现至少有两个下游 cAMP 效应子、PKA（蛋白激酶 A) 和 Epac2（由 cAMP 2 直接激活的交换蛋白），有助于 cAMP 依赖性 MF LTP。 尽管有这些发现，但仍不清楚这些效应器的信号传导如何导致释放增加 MF 突触中的重要靶点和底物涉及 MF LTP。 在这里，我们将使用领先的蛋白质组学、生物化学和 电生理学方法来确定 cAMP 效应器的信号传导伙伴，并揭示 其作用的生理机制。因此，在目标 1 中，我们将采用正交方法来找到 PKA 和 Epac2 的相互作用子和底物，并通过原位高分辨率标记来验证这些。 在目标 2 中，我们将确定增加释放的确切生理机制 使用组合的光激活-敲除/药理学策略来控制 MF 突触的神经递质。在 最终目标，我们将回答这些不同但趋同的机制如何在 自然活动模式，以及这些效应器的选择性破坏是否会损害小鼠的能力 将情景记忆的形成和检索的相似模式分开。