Regulation of Synapse Morphogenesis in Drosophila

果蝇突触形态发生的调控

基本信息

批准号：
8248274
负责人：
David L. Van Vactor
金额：
$ 36.34万
依托单位：
HARVARD MEDICAL SCHOOL
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-04-01 至 2015-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8248274
关键词：
Accounting Actins Animals Architecture Autistic Disorder Biological Models Biology Brain Cell Adhesion Molecules Cells Communication Conceptions Data Defect Development Disease Dissection Drosophila genus Embryo Epilepsy FMR1 Gene Family Fragile X Syndrome Functional disorder Future Gene Targeting Genes Genetic Epistasis Genetic Models Goals Growth Impaired cognition Intercellular Junctions Knowledge Logic Maintenance Mammals Mediating Mental Retardation MicroRNAs Modeling Molecular Molecular Analysis Morphogenesis Muscle Muscle Cells Neuraxis Neuromuscular Junction Neurons Organism Orthologous Gene Pathway interactions Phenocopy Phenotype Physiology Play Presynaptic Terminals Proteins Proteomics Regulation Regulatory Pathway Relative (related person)Repression Reticulum Role Signal Transduction Staging Stimulus Structure Surveys Synapses Testing Therapeutic Tissues brain malformation cell motility cytomatrix density fascinate gain of function in vivo insight loss of function member nervous system disorder neuroglian postsynaptic presynaptic public health relevance relating to nervous system synaptic function synaptogenesis tool

项目摘要

DESCRIPTION (provided by applicant): Dysfunction in the molecular pathways that regulate synapse form and function leads to a number of neurological disorders, including epilepsy, autism and mental retardation. Our goal is to explore the molecular machinery that mediates synapse development and morphogenesis. This fundamental knowledge will be important for our understanding of neurological disease and for the conception of future therapeutic tools. Using the Drosophila neuromuscular junction (NMJ) as a genetic model system, we have discovered that miR- 8, a member of the highly conserved miR-200 family of microRNAs (miRNAs), is essential for the normal growth and complexity of the synapse. Animals lacking miR-8 display NMJ defects at different stages of development. During larval stages, when NMJs dramatically expand under control of multiple stimuli and regulatory pathways, miR-8 is required in muscle cells to promote the growth of presynaptic terminals. Our analysis suggests that miR-8 is required for the normal architecture of the cytomatrix which defines subsynaptic reticulum (SSR) of the NMJ, a structure analogous to the postsynaptic density marked by PSD-95 in mammals. Multiple screens to define downstream effectors suggest that miR-8 regulates the expression of several target genes implicated in synaptogenesis and cytoskeletal biology. To better define the mechanisms downstream of miR-8, we have shown that postsynaptic repression of the actin-associated protein Enabled (Ena) plays an important role in controlling NMJ growth in late larval stages, consistent with the localization of Ena to the SSR. Ena is predicted to be a direct target of miR-8, and controls aspects of cytoskeletal structure and dynamics during cell movement and cell junction formation, but its role(s) at the synapse are not understood. Preliminary data also indicate that although miR-8 is expressed in the central nervous system (CNS), its activity is somehow suppressed in neurons relative to other tissues. Moreover, genetic epistasis reveals that miR-8 is required for NMJ expansion induced by activation of a key presynaptic pathway that limits synapse morphogenesis (the Fragile-X Mental Retardation gene, FMR1), suggesting that some type of trans- synaptic communication is involved upstream of postsynaptic miR-8. Together, these findings reveal a fascinating mechanism that regulates synapse development, and a wonderful opportunity to exploit a powerful and well-defined model system to understand the logic of miRNA control over synapse form and function. However, many additional studies will be required to define the developmental, cellular and molecular mechanisms required for miR-8 to exert its effects at the NMJ. PUBLIC HEALTH RELEVANCE: Recent insights reveal that microRNAs provide essential regulatory mechanisms during synapse development. Dysfunction in the molecules and pathways that control synaptic morphogenesis leads to neurological disorders such as mental retardation and autism, however, our understanding of the regulatory mechanisms upstream is limited. We will determine the strategy by which Drosophila miR-8 promotes synapse formation as a model to better define the logic of pathways upstream and downstream of synaptic microRNAs.

描述（由申请人提供）：调节突触形式和功能的分子途径中的功能障碍会导致许多神经系统疾病，包括癫痫，自闭症和智力低下。我们的目标是探索介导突触发育和形态发生的分子机制。这种基本知识对于我们对神经系统疾病的理解和未来治疗工具的概念至关重要。将果蝇神经肌肉结（NMJ）作为遗传模型系统，我们发现Mir-8是高度保守的miR-200 microRNA家族（miRNA）的成员，对于突触的正常生长和复杂性至关重要。缺乏miR-8的动物在发育的不同阶段显示NMJ缺陷。在幼虫阶段，当NMJ在控制多个刺激和调节途径的控制下大幅扩展时，肌肉细胞中需要miR-8才能促进突触前末端的生长。我们的分析表明，MIR-8是Cytomatrix的正常结构所必需的，该结构定义了NMJ的突触次触觉网状（SSR），NMJ的结构类似于哺乳动物中PSD-95标记的突触后密度。定义下游效应子的多个筛选表明miR-8调节与突触发生和细胞骨架生物学有关的几个靶基因的表达。为了更好地定义miR-8下游的机制，我们表明，启用肌动蛋白相关蛋白（ENA）的突触后抑制（ENA）在控制幼虫晚期阶段的NMJ生长方面起着重要作用，这与ENA定位在SSR上的定位一致。预计ENA是miR-8的直接靶标，并且控制细胞运动和细胞连接形成过程中细胞骨架结构和动力学的各个方面，但其在突触中的作用尚不清楚。初步数据还表明，尽管miR-8在中枢神经系统（CNS）中表达，但相对于其他组织，其活性在某种程度上抑制了神经元中的活性。此外，遗传上的上毒表明，通过激活关键突触前途径引起的NMJ扩展所必需的miR-8，该途径限制了突触形态发生（Frighile-X智力低下基因，FMR1），这表明某种类型的反式突触涉及Synaptic miR-8的上游。这些发现共同揭示了一种引人入胜的机制，可以调节突触的发展，并是利用强大且定义明确的模型系统来理解miRNA控制对突触形式和功能的逻辑的绝佳机会。但是，将需要许多其他研究来定义miR-8在NMJ上发挥作用所需的发育，细胞和分子机制。公共卫生相关性：最近的见解表明，microRNA在突触开发过程中提供了基本的调节机制。控制突触形态发生的分子和途径的功能障碍会导致神经系统疾病，例如智力低下和自闭症，但是，我们对上游调节机制的理解受到限制。我们将确定果蝇miR-8促进突触形成的策略，以更好地定义突触microRNA上游和下游途径的逻辑的模型。