Characterization of miRNAs on neural development and plasticity

miRNA 对神经发育和可塑性的表征

• 批准号: 8556964
• 负责人: Zheng Li
• 金额: $ 56.93万
• 依托单位: NATIONAL INSTITUTE OF MENTAL HEALTH
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8556964
• 关键词: 3' Untranslated Regions; Actins; Animal Model; Apoptosis; Base Pairing; Binding; Binding Sites; Biochemical; Bioinformatics; Biological; Biological Assay; Biological Process; Brain; Brain Injuries; Brain region; Cell Death; Cell Differentiation process; Cell physiology; Cells; Cessation of life; Cognition; Cognitive deficits; DNA Sequence Rearrangement; Databases; Dendritic Spines; Development; Emotional; Emotions; Environment; Functional RNA; Gene Expression; Gene Expression Profile; Gene Targeting; Genes; Genetic Transcription; Goals; Hippocampus (Brain); Hour; Human; Image; Impairment; Inflammatory Response; Injury; Lead; Learning; Leukocytes; Life; Mammals; Memory; Mental disorders; Messenger RNA; Metabolic; MicroRNAs; Modeling; Molecular; Molecular Profiling; Morphogenesis; Morphology; Mus; Neuronal Plasticity; Neurons; Nucleotides; Ontology; Orthologous Gene; Pathology; Pathway interactions; Play; Problem behavior; Protein Denaturation; Psyche structure; RNA Degradation; Rattus; Recovery; Regulator Genes; Role; Secondary to; Seeds; Signal Pathway; Staging; Stress-Induced Protein; Survivors; Symptoms; Synapses; Synaptic Transmission; Synaptic plasticity; Time; Translations; Trauma; Traumatic Brain Injury; Vertebral column; controlled cortical impact; disability; exhaustion; functional disability; molecular marker; neural circuit; neurodevelopment; neuropsychiatry; prevent; protein aggregation; protein expression; repaired; response

This year we studied traumatic brain injury (TBI) in rat to identify miRNAs which are important in repressing gene expression and regulating biological processes, such as cell differentiation, proliferation and apoptosis. TBI leads to temporary or permanent structural and functional impairment of the brain which is a leading cause of injury-related death and disability. Survivors of TBI show neuropsychiatric abnormalities such as cognitive deficits in addition to emotional and behavioral problems which are common and contribute substantially to post-TBI disabilities. One of the brain regions vulnerable to TBI is the hippocampus which is responsible for cognition and emotion. Pathological changes observed in TBI-hippocampus are cell loss, disturbed neural circuits, impaired synaptic transmission and plasticity, all of which lead to neuropsychiatric symptoms. The mechanisms responsible for hippocampus damage and recovery post-TBI remain unclear. However, these structural and functional changes result from altered gene expression in several brain regions, as has been shown in human and animal models of TBI. And again, the mechanisms for gene expression changes are also unclear. The target of our study, microRNAs, are critical for proper brain functions and their loss causes changes in synaptic protein expression, synaptic transmission, dendritic spine morphology, learning and memory. Previous studies have shown that TBI alters mRNA (messenger RNA) expression in the hippocampus. Altered miRNA expression more than likely impacts their target mRNA expression, so it is possible that miRNAs play a role in regulating gene expression in TBI. Since molecular and cellular mechanisms subserving neuronal damage and impairment in TBI mental abilities are largely unknown, we used deep-sequencing to delineate miRNA transcriptome changes in hippocampus at 24hr and day 7 post-TBI in the rat controlled cortical impact injury model (CCI). We also developed a bioinformatics analysis, called miRNA-gene-GO Enrichment, to computationally examine the potential effects of miRNA expression changes in CCI. The analysis was performed in these three general steps: 1) match rat miRNAs resulting from deep-sequencing to their mouse orthologs via the TargetScan database, 2) compile computationally predicted target genes of the mouse miRNA orthologs and estimate their statistical significance of enrichment, and 3) obtain the GO terms that annotate the over-represented genes from the Gene Ontology database and perform enrichment analysis on each of three sets of GO terms (biological process, molecular function, and cellular component). The GO enrichment analysis revealed that both the 24hr and 7 day post-CCI miRNAs correspond to the secondary damage stage (i.e. histological, biochemical, metabolic and cellular changes) of TBI, which occurs minutes to days or even months after the initial trauma. These types of cellular responses are essential to the initiation of secondary damage, and are thought to impact TBI-related structural and functional impairments of neurons. These findings are consistent with known post-trauma pathological changes. In addition, distinct GO terms are identified for the two post-CCI time points. At 24 hours the miRNAs are modulated to inhibit leukocyte cell death for the inflammatory response, prevent stress-induced protein denaturation and aggregation, and protect cells from energy exhaustion. At the 7 day time point, cells switch to miRNAs that support a cellular environment for repair and structural remodeling. Our study of the effect of CCI injury on the miRNA transcriptome in the hippocampus and identification of cellular functions and biological processes potentially regulated by miRNAs in the damaged hippocampus found distinct sets of miRNAs regulated at different post-CCI times, and suggest that multiple miRNAs cooperatively regulate cellular pathways for the pathological changes and management of brain injury. These distinct miRNAs expression profiles at different post-CCI times may be used as molecular markers to assess TBI progression. The bioinformatics analysis showed the miRNAs target to multiple GO terms in a post-CCI time specific manner which indicated that miRNAs act together to regulate a broad range of cellular functions in the brain at different stages of TBI. These identified biological pathways may be potential targets for development of new TBI treatments. In addition to traumatic brain injury, we investigated the role of miRNAs in synapse development by combining deep-sequencing, bioinformatics and live imaging. miRNAs differentially expressed in hippocampal neurons during spine morphogensis were identified by profiling miRNA transcriptomes. Bioinformatics analysis was conducted to determine mRNA targets and cellular processes statistically enriched by the identified miRNAs. The functions of several miRNAs were examined by live imaging of hippocampal neurons. Our study shows that miRNAs are essential for spine morphogenesis. We also identified the target genes through which these miRNAs regulate spines, and demonstrated that translation-dependent actin rearrangement plays important roles in spine remodeling. These findings reveal that by impinging on the expression of diverse targets, miRNAs orchestrate networks of cellular processes essential for synapse development.

今年，我们研究了大鼠创伤性脑损伤（TBI），以鉴定在抑制基因表达和调节生物过程（如细胞分化、增殖和凋亡）中重要的miRNA。TBI导致大脑的暂时或永久性结构和功能损伤，这是与损伤相关的死亡和残疾的主要原因。 TBI的幸存者显示出神经精神异常，如认知缺陷，除了情绪和行为问题，这是常见的，并大大有助于TBI后残疾。易受TBI影响的大脑区域之一是负责认知和情感的海马体。在TBI-海马中观察到的病理变化是细胞丢失、神经回路紊乱、突触传递和可塑性受损，所有这些都导致神经精神症状。脑外伤后海马损伤和恢复的机制尚不清楚。然而，这些结构和功能的变化是由几个脑区的基因表达改变引起的，如在TBI的人类和动物模型中所示。 同样，基因表达变化的机制也不清楚。 我们研究的目标是microRNA，它对正常的脑功能至关重要，它们的缺失会导致突触蛋白表达、突触传递、树突棘形态、学习和记忆的变化。先前的研究表明，TBI改变了海马中的mRNA（信使RNA）表达。改变的miRNA表达更可能影响其靶mRNA表达，因此miRNA可能在TBI中调节基因表达中起作用。 由于分子和细胞机制subserving神经元损伤和损伤的TBI精神能力在很大程度上是未知的，我们使用深度测序描绘在海马中的miRNA转录组的变化，在24小时和7天后TBI在大鼠控制的皮质撞击损伤模型（CCI）。 我们还开发了一种生物信息学分析，称为miRNA-基因-GO富集，以计算方式检查CCI中miRNA表达变化的潜在影响。在这三个一般步骤中进行分析：1）通过TargetScan数据库将深度测序产生的大鼠miRNA与其小鼠直系同源物匹配，2）编译小鼠miRNA直系同源物的计算预测的靶基因并估计其富集的统计学显著性，以及3）获得注释过-从Gene Ontology数据库中提取代表的基因，并对三组GO术语（生物过程、分子功能和细胞组分）中的每一组进行富集分析。GO富集分析显示CCI后24小时和7天的miRNA均对应于TBI的继发性损伤阶段（即组织学、生物化学、代谢和细胞变化），其发生在初始创伤后数分钟至数天或甚至数月。这些类型的细胞反应对于继发性损伤的起始是必不可少的，并且被认为影响TBI相关的神经元结构和功能损伤。这些发现与已知的创伤后病理变化一致。此外，确定了两个CCI后时间点的不同GO术语。在24小时，调节miRNA以抑制白细胞因炎症反应而死亡，防止应激诱导的蛋白质变性和聚集，并保护细胞免于能量耗尽。在第7天的时间点，细胞转换为支持细胞环境以进行修复和结构重塑的miRNA。 我们研究了CCI损伤对海马中miRNA转录组的影响，并鉴定了受损海马中可能由miRNA调节的细胞功能和生物学过程，发现了不同的miRNA组在CCI后不同时间受到调节，并表明多种miRNA协同调节脑损伤病理变化和管理的细胞途径。这些在CCI后不同时间的不同miRNA表达谱可用作评估TBI进展的分子标志物。生物信息学分析显示，miRNA以CCI后时间特异性方式靶向多个GO术语，这表明miRNA在TBI的不同阶段共同作用以调节脑中广泛的细胞功能。这些确定的生物学途径可能是开发新的TBI治疗的潜在目标。 除了创伤性脑损伤，我们还通过结合深度测序、生物信息学和实时成像研究了miRNA在突触发育中的作用。通过分析miRNA转录组，鉴定了在脊髓形态发生过程中海马神经元中差异表达的miRNA。进行生物信息学分析以确定由所鉴定的miRNA统计学富集的mRNA靶标和细胞过程。通过海马神经元的实时成像来检查几种miRNA的功能。我们的研究表明，miRNA是脊柱形态发生所必需的。我们还确定了这些miRNAs调控棘的靶基因，并证明了依赖于肌动蛋白重排的肌动蛋白重排在棘重塑中起着重要作用。这些发现表明，通过影响不同靶点的表达，miRNA协调了突触发育所必需的细胞过程网络。