Molecular and Cellular Correlates of Plasticity in Hippocampal-Prefrontal Circuitry

资助金摘要 海马体-前额叶回路与许多神经精神疾病有关。这条赛道非常关键 参与认知和情绪调节，特别容易受到压力的影响，这是一个关键的诱因 导致这些疾病的因素。慢性应激对神经元结构和生理功能的有害影响 在海马区，并损害海马体依赖行为，包括背景恐惧的处理。这个 在认知和情绪任务中，海马区(HPC)和前额叶皮质(PFC)通过改变 这两个区域之间振荡活动的一致性。然而，细胞和分子事件 HPC-PFC同步中的驱动器变化并不是很好地理解。腹侧CA1区投射的神经元 HPC为PFC提供主要的单突触输入。神经精神疾病的许多危险因素 包括应激在内的疾病会影响在突触发育和可塑性中发挥重要作用的基因，以及 HPC和PFC之间神经元投射的突触连接中断可能导致 HPC-PFC同步中的损伤。这一提议的中心假设是细胞和分子 HPC-PFC投射神经元中的信号控制其结构和功能，这些信号通路 调节HPC和PFC之间的神经活动模式，影响它们的连接性。这样做的目的是 应用1)了解压力如何驱动HPC-PFC投射细胞中的分子和细胞信号 以控制其生理功能；以及2)确定HPC-PFC投射神经元的可塑性如何影响 控制恐惧相关行为的功能连接。这项受资助的申请有三个目的，旨在揭示 关于HPC-PFC投射神经元的分子和细胞信号程序的基本信息。目标 1：确定压力如何影响海马体前额叶回路的神经活动，以驱动增强的恐惧回忆； 目的2：确定海马-前额叶投射神经元的可塑性调节机制 HPC和PFC之间的功能连接；目标3：确定压力如何影响分子和结构 海马额前投射神经元可塑性的相关性。我们在AIMS 2上取得了实质性进展 具体来说，我们在HPC-PFC投影机中成功、稳定地过表达了BDNF，并获得了LFP 在植入立体电极的HPC和PFC中评估BDNF表达如何影响这一区域的连接性 并同时评估了恐惧回忆过程中单个PFC神经元中的钙活动。迈向目标 在目标3中，我们在PFC中进行了选择性刺激后的单核rna测序。 HPC-PFC投射神经元和对照投射神经元类型蓝斑(LC)-PFC神经元。一个 来自这些研究的关键的、意想不到的发现，我们用RNAScope技术在细胞分辨率上进行了验证， 是刺激LC-PFC神经元后选择性上调PFC神经元载脂蛋白E(ApoE)。

Summary of funded grant The hippocampal-prefrontal circuit is implicated in many neuropsychiatric illnesses. This circuit is critically involved in cognition and emotional regulation, and is particularly vulnerable to stress, which is a key precipitating factor for these disorders. Chronic stress has deleterious effects on neuronal structure and physiological function in the hippocampus, and impairs hippocampal-dependent behavior, including processing of contextual fear. The hippocampus (HPC) and prefrontal cortex (PFC) communicate during cognitive and emotional tasks by altering the coherence of oscillatory activity between the two regions. However, the cellular and molecular events that drive changes in HPC-PFC synchrony are not well understood. Neurons projecting from the ventral CA1 region of the HPC provide the major monosynaptic input to the PFC. Many of the risk factors for neuropsychiatric disorders, including stress, affect genes that play important roles in synapse development and plasticity, and disruptions in synaptic connections of the neuronal projections between the HPC and PFC could contribute to impairments in HPC-PFC synchrony. The central hypothesis of this proposal is that cellular and molecular signaling in HPC-PFC projection neurons control their structure and function, and that these signaling pathways regulate patterns of neural activity between the HPC and PFC that influence their connectivity. The goals of this application are to 1) understand how stress drives molecular and cellular signaling in HPC-PFC projection cells to control their physiological function; and 2) determine how plasticity in HPC-PFC projection neurons impacts functional connectivity to control fear-related behavior. The funded application has three aims, designed to reveal fundamental information about molecular and cellular signaling programs in HPC-PFC projection neurons. Aim 1: Identify how stress impacts neural activity in hippocampal-prefrontal circuitry to drive enhanced fear recall; Aim 2: Determine how manipulation of plasticity in hippocampal-prefrontal projection neurons mediates functional connectivity between the HPC and PFC; Aim 3: Define how stress impacts molecular and structural correlates of plasticity in hippocampal-prefrontal projection neurons. We made substantial progress on Aims 2 and 3. Specifically, we successfully and stably overexpressed BDNF in HPC-PFC projectors, and acquired LFPs in HPC and PFC from implanted stereotrodes to assess how BDNF expression impacted connectivity in this circuit, and in parallel, assessed calcium activity in individual PFC neurons during fear recall. Towards the goals of Aim 3 we conducted single-nuclei RNA sequencing (snRNA-seq) in PFC following selective stimulation of both HPC-PFC projection neurons and a comparator projection neuron type - locus coeruleus (LC)-PFC neurons. A key, unexpected finding from these studies, which we validated at cellular resolution with RNAscope techn y, is selective upregulation of apolipoprotein E (ApoE) in PFC neurons after stimulation of LC-PFC neurons.