Targets of microRNA-132 in adult neurogenesis

microRNA-132 在成人神经发生中的靶标

基本信息

批准号：
8201725
负责人：
Xiaolu Ang Cambronne
金额：
$ 4.84万
依托单位：
OREGON HEALTH & SCIENCE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-07-01 至 2013-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8201725
关键词：
3&apos Untranslated Regions Ablation Accounting Acute Address Adult Affect Aging Antidepressive Agents Area Biological Assay Brain Brain region C-terminal CREB1 gene Cells Complex Conflict (Psychology)Cultured Cells Data Dendrites Development Disease Dominant-Negative Mutation Down-Regulation EGF gene Epithelial Excision Exonuclease Family Fibrinogen Functional RNA Gene Expression Genes Growth Factor Heparin Binding Hippocampus (Brain)Human In Vitro Indium Injury Knock-out Learning Life Luciferases Mediating Memory Messenger RNA MicroRNAs Modeling Molecular Mutate Neurons Newborn Infant Nucleotides Paper Parahippocampal Gyrus Pathway interactions Phenocopy Phenotype Positioning Attribute Process Publishing RNA Interference RNA-Induced Silencing Complex Regulation Repression Role Screening for Neuroblastoma Signal Pathway Signal Transduction Synapses Testing Time Transcript Translating Whole Organism adult neurogenesis cellular targeting cohort dentate gyrus granule cell in vivo insight interest mRNA Expression member mouse model nerve stem cell neuroblastoma cell neurogenesis newborn neuron novel novel strategies overexpression research study response synaptogenesis transcription factor

项目摘要

DESCRIPTION (provided by applicant): One distinguishing attribute of the mammalian hippocampus is its ability to continuously produce newborn neurons throughout adult life. These newborn neurons are first exposed to GABAergic signals as they emerge from the subgranule layer of the dentate gyrus. This activity drives a CREB-dependent signaling pathway that alters the gene expression within that newborn neuron, and as such, is required for its maturation and survival. Nevertheless, the exact mechanism is still poorly understood as to how CREB-signaling translates into the maturation, survival, and functional integration of that particular cell into the hippocampal circuitry. We do know that one of the important CREB targets for the maturation of adult newborn neurons in vivo is non-coding transcript microRNA-132 (miR-132). When we excised the miR-132 locus in adult newborn neurons it resulted in an immature dendritic arbor that phenocopied disruption of CREB signaling. Nevertheless as a microRNA, miR-132 has the ability to downregulate a number of diverse transcripts. The important issue that this proposal addresses is the identification and characterization of specific miR-132 targets that contribute to this establishment of the dendritic arbor. Without understanding the identity of specific cellular targets, we cannot fully appreciate the regulation conferred by miR-132, and only know that its activity is required for this process. Through preliminary screens and the availability of a mouse model, I am in a unique position to characterize how the regulation of candidate target Heparin-binding Epithelial Growth Factor (Hb-EGF) by miR- 132 contributes to the dendritic arbor of newborn neurons. Preliminary data demonstrate that levels of Hb-EGF are dramatically downregulated specifically in response to miR-132 activity. Aim 1 takes advantage of being able to target excision of the miR-132 locus in the adult newborn neurons of the floxed mouse model to examine how Hb-EGF is regulated by miR-132 in these cells. Changes in Hb-EGF levels will be evaluated for how they affect dendritic arborization, and then we will determine whether depletion of Hb-EGF can rescue the immature dendritic phenotype that occurs with miR-132 activity is ablated in adult newborn neurons. It is likely that other miR-132 direct targets are also important for maturation of the adult newborn neuron. To identify direct miR-132 targets that may function with Hb-EGF, I have developed a molecular miR- 132 target trap that I will develop into a screen in Aim 2. This approach takes advantage of a dominant- negative RNAi-Induced Silencing Complex (RISC)- a central component in the microRNA pathway that bridges the recognition of microRNAs and their targets-to stabilize and capture associated mRNA target transcripts that would otherwise decay via deadenylation and exonuclease activity. PUBLIC HEALTH RELEVANCE: In order to address how adult neurogenesis relates to human aging, disease, and injury, it is absolutely vital to have a clear and detailed understanding of the molecular mechanisms underlying this process. Over the years various cellular factors have been implicated in the establishment and maturation of adult newborn neurons, however, the revelation that activity- dependent microRNA-132 is important in this process provides a unique opportunity to flesh out significant and specific molecular pathways in greater depth. This proposal brings together detailed preliminary data from in vitro molecular studies-which reveal mechanistic insight down to the specific nucleotides that are targeted my miR-132-with important in vivo analysis of how the identified regulation affects the development of these newborn neurons within the context of a whole organism.

描述（由申请人提供）：哺乳动物海马体的一个显着属性是其在整个成年过程中持续产生新生神经元的能力。这些新生神经元在从齿状回的亚颗粒层出现时首先暴露于 GABA 信号。这种活性驱动 CREB 依赖性信号通路，改变新生神经元内的基因表达，因此是其成熟和存活所必需的。然而，关于 CREB 信号如何转化为特定细胞的成熟、存活和功能整合到海马回路中的确切机制仍然知之甚少。我们确实知道，成年新生神经元体内成熟的重要 CREB 靶标之一是非编码转录本 microRNA-132 (miR-132)。当我们切除成年新生神经元中的 miR-132 基因座时，会产生不成熟的树突状乔木，从而表现出 CREB 信号传导的破坏。然而，作为一种 microRNA，miR-132 具有下调多种不同转录本的能力。该提案解决的重要问题是有助于树突乔木建立的特定 miR-132 靶标的识别和表征。如果不了解特定细胞靶标的身份，我们就无法完全理解 miR-132 赋予的调节作用，只能知道其活性是该过程所必需的。通过初步筛选和小鼠模型的可用性，我处于一个独特的位置来描述 miR-132 对候选靶标肝素结合上皮生长因子 (Hb-EGF) 的调节如何促进新生神经元的树突状结构。初步数据表明，Hb-EGF 水平显着下调，特别是响应 miR-132 活性。目标 1 利用能够靶向切除 floxed 小鼠模型的成年新生神经元中的 miR-132 基因座来检查这些细胞中 miR-132 如何调节 Hb-EGF。我们将评估 Hb-EGF 水平的变化如何影响树突状树枝化，然后我们将确定 Hb-EGF 的消耗是否可以挽救成年新生神经元中 miR-132 活性被消除时出现的不成熟树突表型。其他 miR-132 直接靶标可能对于成年新生神经元的成熟也很重要。为了识别可能与 Hb-EGF 一起发挥作用的直接 miR-132 靶点，我开发了一种分子 miR-132 靶点陷阱，我将在目标 2 中将其开发为筛选。这种方法利用了显性失活 RNAi 诱导的沉默复合物(RISC) - microRNA 通路中的核心组件，连接 microRNA 及其靶标的识别 - 以稳定和捕获相关的 mRNA 靶标转录本，否则这些转录本会通过脱腺苷化和核酸外切酶而衰减活动。公共健康相关性：为了解决成人神经发生与人类衰老、疾病和损伤之间的关系，清楚而详细地了解这一过程背后的分子机制绝对至关重要。多年来，各种细胞因素与成年新生神经元的建立和成熟有关，然而，活动依赖性 microRNA-132 在此过程中的重要作用的揭示提供了一个独特的机会，可以更深入地充实重要和特定的分子途径。该提案汇集了来自体外分子研究的详细初步数据——这些数据揭示了针对 miR-132 的特定核苷酸的机制见解——以及重要的体内分析，即所识别的调节如何影响这些新生神经元的发育。一个完整的有机体。