miR132 regulation of neuronal plasticity, learning, and memory

miR132 对神经元可塑性、学习和记忆的调节

• 批准号: 8256198
• 负责人: Katelin L.F. Hansen
• 金额: $ 3.53万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-30 至 2014-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8256198
• 关键词: 3' Untranslated Regions; Adult; Affect; Alzheimer' s Disease; Behavioral; Behavioral Paradigm; Bioinformatics; Biological; CREB1 gene; Cell Culture Techniques; Cells; Code; Cognition; Cognitive; Cognitive deficits; Data; Dendrites; Development; Developmental Process; Disease; Doxycycline; Exposure to; Fluorescent in Situ Hybridization; Functional RNA; Gene Expression; Gene Expression Profile; Genetic Transcription; Genetic Translation; Hippocampus (Brain); Huntington Disease; Immunofluorescence Immunologic; Immunolabeling Technics; Impaired cognition; In Situ Hybridization; In Vitro; Label; Lead; Learning; Memory; Memory impairment; Mental disorders; Messenger RNA; MicroRNAs; Molecular; Molecular Target; Morphogenesis; Morphology; Mouse Strains; Mus; Nature; Nervous System Physiology; Nervous system structure; Neuronal Plasticity; Neurons; Nucleotides; Output; Pattern; Performance; Phenocopy; Phenotype; Plastics; Play; Population; Process; Prosencephalon; Publishing; RNA Binding; RNA-Induced Silencing Complex; Regulation; Research; Rett Syndrome; Role; Schizophrenia; Seeds; Signal Transduction; Signaling Molecule; Stem cells; Sum; Synaptic plasticity; Techniques; Testing; Tetanus Helper Peptide; Tetracycline Control; Tetracyclines; Tissues; Transcript; Transgenes; Transgenic Mice; Transgenic Model; Transgenic Organisms; Untranslated RNA; Vertebral column; Work; base; cognitive enhancement; density; dentate gyrus; drinking water; environmental enrichment for laboratory animals; gene induction; in vivo; interest; memory recognition; mouse model; novel therapeutics; promoter; research study; response; transgene expression; treatment strategy

Inducible gene expression plays a central role in neuronal plasticity, learning, and memory. Dysregulation of these processes can lead to severe neuronal disorders and cognitive impairment. In addition to coding transcripts (mRNAs), non-coding microRNA (miRNAs) appear to play a regulatory role in the neuronal plasticity. miRNAs are small, evolutionarily-conserved signaling molecules that act as silencing regulators of mRNA targets. Disruption of miRNA expression and signaling is associated with severe cognitive impairment. Thus, the functional role of miRNAs in nervous system physiology and cognition merits close examination. This proposal focuses on the CREB-regulated miRNA132 (miR132), which has been shown to be expressed in an activity-dependant manner in vitro and in vivo. Altered miR132 is associated with several psychiatric (schizophrenia) and degenerative (Huntington's disease) disorders of the nervous system. Recently, my published work using a miR132 transgenic mouse strain revealed that miR132 significantly regulates hippocampal dendrite spinogenesis in vivo, as well as recognition memory. However, the details of miR132's molecular regulation and its behavioral consequences remain unclear. I hypothesize that miR132 is expressed in mature and developing neurons throughout the hippocampus, and its inducible expression is required for normal memory formation. As an extension of this idea, I further propose that miR132 levels (both basal and inducible) must be tightly controlled, and that deviation from this range will result in cognitive deficits. Here, I propose a strategy to assess the hippocampal expression of miR132, to explore its behavioral/cognitive consequences and to profile a subset of its putative molecular (mRNA) targets. To this end, Aim 1 will utilize in situ hybridization and immunolabeling techniques to examine basal miR132 expression patterns within the hippocampus, as well as profile its inducible expression following environmental enrichment and learning paradigms. In Aim 2, I will employ the noted tetracycline-regulated transgenic mouse strain (tTA:miR132) that expresses miR132 in forebrain neurons to explore the contribution of miR132 to learning and memory. To this end, I will initially profile cognitive consequences of tonic transgenic miR132 expression. I will then examine whether the miR132 learning phenotype is plastic in nature, or whether it is fixed (i.e. a permanent cognitive deficit) by taking advantage of the tetracycline-controlled promoter to shut down transcription of the transgenic miR132. Finally, although I have shown that tonically high levels of transgenic miR132 impair learning, I hypothesize that there exists an optimized level of miR132 expression that facilitates cognitive performance. This idea will be tested in experiments which will titer transgenic miR132 (using doxycycline) to parallel the level observed following environmental enrichment, in an attempt to phenocopy cognitive enhancement resulting environmental enrichment. Finally, Aim 3 proposes to use the Solexa Deep Sequencing technique to profile downstream targets of miR132 in the tTA::miR132 mouse strain. Further, a small subset of these targets (5 in total) will be validated using molecular and histological approaches. In sum, a more complete understanding of miR132's role in neuronal signaling and cognition should further our efforts to develop novel therapeutic strategies for the treatment of a variety of mental disorders.

诱导基因表达在神经元可塑性、学习和记忆中起着核心作用。这些过程的失调可导致严重的神经障碍和认知障碍。除了编码转录本（mrna）外，非编码microRNA （mirna）似乎在神经元可塑性中发挥调节作用。mirna是一种小的，进化保守的信号分子，作为mRNA靶点的沉默调节因子。miRNA表达和信号的中断与严重的认知障碍有关。因此，mirna在神经系统生理和认知中的功能作用值得深入研究。这一建议的重点是creb调控的miRNA132 (miR132)，它已被证明在体外和体内以活性依赖的方式表达。miR132的改变与几种精神疾病（精神分裂症）和神经系统退行性疾病（亨廷顿氏病）有关。最近，我发表的使用miR132转基因小鼠品系的研究表明，miR132在体内显著调节海马树突棘发生，以及识别记忆。然而，miR132的分子调控细节及其行为后果尚不清楚。我假设miR132在整个海马的成熟和发育神经元中表达，其诱导表达是正常记忆形成所必需的。作为这一观点的延伸，我进一步提出miR132水平（基础和诱导）必须严格控制，偏离这一范围将导致认知缺陷。在这里，我提出了一种评估miR132海马表达的策略，以探索其行为/认知后果，并描述其假定的分子（mRNA）靶标子集。为此，Aim 1将利用原位杂交和免疫标记技术来检查海马体内基本的miR132表达模式，并在环境富集和学习范式下描述其诱导表达。在Aim 2中，我将使用著名的四环素调节转基因小鼠品系（tTA:miR132），在前脑神经元中表达miR132，以探索miR132对学习和记忆的贡献。为此，我将首先介绍补性转基因miR132表达的认知后果。然后，我将通过利用四环素控制的启动子来关闭转基因miR132的转录，来检查miR132的学习表型在本质上是可塑的，还是固定的（即永久的认知缺陷）。最后，虽然我已经证明了高水平的转基因miR132损害学习，但我假设存在一个优化的miR132表达水平，促进认知表现。这一想法将在实验中进行测试，该实验将滴度转基因miR132（使用强力霉素），以平行于环境富集后观察到的水平，试图表型认知增强导致环境富集。最后，Aim 3提出使用Solexa Deep Sequencing技术来分析tTA::miR132小鼠品系中miR132的下游靶点。此外，这些靶点的一小部分（总共5个）将使用分子和组织学方法进行验证。总之，更全面地了解miR132在神经元信号传导和认知中的作用，将进一步推动我们开发治疗各种精神障碍的新治疗策略。