Cell-specific Functional and Transcriptomic Analysis of Plasticity Pathways in MECP2-Duplication Syndrome

MECP 2重复综合征是由MECP 2基因重复引起的，导致进行性智力障碍。 残疾、自闭症、运动功能障碍、痉挛和癫痫。突触可塑性 多种自闭症谱系障碍的病因机制，包括甲基CpG结合蛋白-2 （MECP 2）重复综合征。我们最近描述了一种异常的突触可塑性表型在Tg 1 MECP 2-复制综合征小鼠模型，涉及Ras/MAPK通路。然而，细胞特异性 有关可塑性途径的研究还有待进行。表征共同的可塑性途径 自闭症谱系障碍（ASD）的功能障碍主题对于确定新的治疗目标具有潜在的巨大价值。 干预直到最近，还不可能原位测量单个细胞的转录组，并将其与细胞的生长和分化相关。 它的功能特性。在这里，我们采用最近开发的高通量原位mRNA杂交技术， 方法（MERFISH），能够解决数百至数千个不同的mRNA转录每个成像会话， 在MECP 2复制的Tg 1小鼠模型中研究学习过程中的皮质可塑性机制 综合征我们使用M Bear介绍的一种强大的视觉训练范式，包括多个演示文稿， 高对比度闪烁光栅。已知这在区域V1+中形成真实的存储器轨迹， 需要睡眠来巩固，具有行为相关性，并与LTP共享核心分子特征。 目的-1：比较MECP 2重复小鼠与同窝小鼠的视觉皮层回路如何与学习功能发生故障 对照视觉反应特性、层内和层间功能连接概况将在 V1区，并在训练前后进行基因型比较。假设：皮层回路的能力， 突变小鼠与对照小鼠的学习以层状特异性方式不同。层间功能连接配置文件将 MECP 2-复制综合征异常，导致皮质间信号传输和处理异常 纹层这将在训练后加剧，导致僵硬，不灵活的神经反应。 目的-2：比较视觉系统中可塑性和神经递质通路的单细胞分辨转录组学特征， MECP 2复制的皮层与经历aim-1中引入的训练范例的对照动物。有关 aim-1中获得的神经元响应与从相同神经元获得的细胞特异性转录组学谱。 假设：我们将获得一个更完整的、特定于细胞的关于可塑性机制如何在细胞中失败的图片 MECP 2复制综合征小鼠模型的新皮质。获得的数据将产生以下假设 这有助于确定未来药物干预的目标。 影响：首次将细胞特异性可塑性和神经递质/离子通道转录组学特征与 在学习过程中体内获得的细胞特性，表征了大脑皮层功能障碍的机制， MECP 2-重复综合征。数据将提供给科学界。随着时间的推移， 自闭症将被纳入这一框架，产生一个路线图，以确定适当的治疗目标，在自闭症。

MECP2-duplication syndrome is caused by duplication of the MECP2 gene leading to progressive intellectual disability, autism, motor dysfunction, spasticity, and epilepsy in males with 100% penetrance. Synaptic plasticity mechanisms are causally implicated in multiple autism spectrum disorders, including Methyl-CpG-binding-protein-2 (MECP2) duplication syndrome. We recently described an abnormal synaptic plasticity phenotype in the Tg1 mouse model of MECP2-duplication syndrome, implicating the Ras/MAPK pathway. However, cell-specific investigation of plasticity pathways involved has yet to be undertaken. Characterizing common plasticity pathway themes of dysfunction in autism spectrum disorders (ASD) is potentially of great value for identifying new targets for intervention. Until recently it has not been possible to measure the transcriptome of individual cells in situ and relate it to their functional properties. Here, we adapt a recently developed high-throughput in-situ mRNA hybridization method (MERFISH), capable of resolving hundreds to thousands of distinct mRNA transcripts per imaging session, to investigate cortical plasticity mechanisms during learning in the Tg1 mouse model of the MECP2-duplication syndrome. We use a robust visual training paradigm introduced by M Bear, consisting of multiple presentations of a high contrast flickering grating at a specific orientation. This is known to form a true memory trace in area V1+ that requires sleep for consolidation, has a behavioral correlate and shares core molecular features with LTP. Aim-1: Compare how visual cortex circuits malfunction with learning in MECP2-duplication mice vs in littermate controls. Visual response properties, intra- and inter-layer functional connectivity profiles will be measured within area V1 and compared across genotypes before and after training. Hypothesis: The capacity of cortical circuits for learning differs in mutant vs control mice in a laminar specific way. Inter-layer functional connectivity profiles will be abnormal in MECP2-duplication syndrome resulting in abnormal signal transmission and processing across cortical laminae. This will be exacerbated post-training leading to rigid, less flexible, neural responses. Aim-2: Compare single-cell resolved transcriptomic profiles of plasticity and neurotransmitter pathways in the visual cortex of MECP2-duplication vs control animals undergoing the training paradigm introduced in aim-1. Relate neuronal responses obtained in aim-1 to cell-specific transcriptomic profiles obtained from the same neurons. Hypothesis: We will acquire a more complete, cell-specific, picture of how mechanisms of plasticity fail in the neocortex of the mouse model of MECP2-duplication syndrome. Data obtained will generate hypotheses for follow up experiments, helping to identify targets for future pharmacologic interventions. IMPACT: Relate for the first time, cell-specific plasticity & neurotransmitter/ion-channel transcriptomic profiles with cell properties acquired in vivo during learning, characterizing the mechanisms underlying cortical dysfunction in MECP2-duplication syndrome. Data will be made available to the scientific community. In time, additional models of autism will be brought into this framework, yielding a roadmap for identifying appropriate therapeutic targets in ASD.