Control of Tripartite Synapse Formation by Astrocytic Neuroligins

星形胶质细胞 Neuroligins 对三联突触形成的控制

• 批准号: 8911667
• 负责人: Jeff Alan Stogsdill
• 金额: $ 4.31万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-02-01 至 2018-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8911667
• 关键词: Adaptor Signaling Protein; Adherence; Adhesions; Architecture; Astrocytes; Autistic Disorder; Axon; Binding; Biological Assay; Brain; Brain Diseases; Cell Adhesion Molecules; Cell Culture System; Cells; Cellular biology; Cognition; Complex; Data; Dendrites; Development; Disease; Electron Microscopy; Electrophysiology (science); Epilepsy; Event; Evolution; Excitatory Synapse; Eye; Family; Gene Expression; Homeostasis; In Vitro; Inhibitory Synapse; Intercellular Junctions; Ions; Label; Learning; Light; Link; Measures; Memory; Mental Depression; Molecular; Morphology; Mus; Neuraxis; Neurodevelopmental Disorder; Neuronal Plasticity; Neurons; Outcome; Physiology; Play; Presynaptic Terminals; Process; Proteins; Publishing; Regulation; Research; Rodent; Role; Signal Transduction; Structure; Synapses; Synaptic plasticity; Techniques; Testing; Time; Trees; Universities; Visual Cortex; Work; base; cognitive function; extracellular; functional outcomes; improved; in vivo; learned behavior; light microscopy; member; mutant; nervous system disorder; neurotransmitter release; novel; novel strategies; postnatal; postsynaptic; presynaptic; public health relevance; research study; response; small hairpin RNA; synaptogenesis

 DESCRIPTION (provided by applicant): Synapses are specialized cell-cell junctions of the central nervous system (CNS) that are critical for learning, memory, and cognition. Localized to these junctions are cell adhesion molecules (CAMs) that link the presynaptic axon with the postsynaptic dendrite, which establish synaptic structure and function. CNS synapses are now considered a three-membered entity, or tripartite synapse, which include the axon terminal, the dendrite, and an ensheathing astrocyte process. Astrocytes are non-neuronal, architecturally complex cells with branches that terminate in thousands of fine processes that interact with synapses. A single mouse astrocyte can contact more than 100,000 synapses at a time. While decades of research have identified how synapses between two neurons are formed, the molecular mechanisms that regulate astrocyte-synapse interactions remain elusive. Additionally, the mechanisms and molecular links between astrocyte morphology and synapse association are unknown. Astrocyte branching complexity develops in the rodent cortex during the second postnatal week, a time of significant excitatory synapse formation. In preliminary experiments I found that astrocytes in vitro require contact with neurons to establish a complex morphology. Because astrocytes specifically contact synapses, it is likely that astrocytes express CAMs to interact with these neuronal adhesions. In preliminary experiments, I discovered that astrocytes express the neuroligin (NL) family of CAMs, which are known to play critical roles at neuronal synapses, and previously thought to be functional only in neurons. NLs are well-studied molecules that regulate synapse formation and structure of dendritic trees. Knockdown of astrocytic NLs in culture by shRNA demonstrated that NLs are required for establishing astrocyte morphology in response to neuronal contact. These data are novel and indicate that there are previously unknown functions of NLs in astrocytes, which potentially link astrocytes to synapses and control complex astrocyte architecture. Based on these observations and previously published results this proposal will utilize novel and well- established techniques to determine how NLs in astrocytes regulate synapse interaction and generate astrocyte architectural complexity. By combining cell biology, light and electron microscopy, and electrophysiology, the aims of this proposal will test the structural and functional requirement of NLs in astrocytes and identify the molecular mechanisms of astrocyte-neuron contact and downstream signaling through astrocytic NLs. The outcomes of this proposal will open exciting new avenues in studying the interactions between neurons and astrocytes throughout development and neural plasticity. NLs are associated with a number or disease states including autism and epilepsy. Therefore the proposed work will illuminate the need for reevaluation of these CAMs within the entirety of the tripartite synapse.

 描述（由申请人提供）：突触是中枢神经系统（CNS）的特化细胞-细胞连接，对学习、记忆和认知至关重要。位于这些连接处的是细胞粘附分子（CAM），其将突触前轴突与突触后树突连接起来，从而建立突触结构和功能。中枢神经系统突触现在被认为是一个三元实体，或三重突触，包括轴突终末，树突和成鞘星形胶质细胞过程。星形胶质细胞是一种非神经元的结构复杂的细胞，其分支终止于数千个与突触相互作用的精细过程。一只老鼠的星形胶质细胞一次可以接触超过10万个突触。虽然几十年的研究已经确定了两个神经元之间的突触是如何形成的，但调节星形胶质细胞-突触相互作用的分子机制仍然难以捉摸。此外，星形胶质细胞形态和突触联系之间的机制和分子联系尚不清楚。 星形胶质细胞分支的复杂性发展在啮齿动物皮层在出生后第二周，一个显着的兴奋性突触形成的时间。在初步实验中，我发现体外星形胶质细胞需要与神经元接触才能建立复杂的形态。由于星形胶质细胞特异性地接触突触，因此星形胶质细胞可能表达CAM以与这些神经元粘附相互作用。在初步实验中，我发现星形胶质细胞表达CAM的神经连接素（NL）家族，已知其在神经元突触中起关键作用，并且以前认为仅在神经元中起作用。神经胶质细胞是一种被广泛研究的调节突触形成和树突树结构的分子。通过shRNA敲低培养物中的星形胶质细胞NLs表明，NLs是建立响应神经元接触的星形胶质细胞形态所必需的。这些数据是新颖的，并表明星形胶质细胞中存在以前未知的NLs功能，其可能将星形胶质细胞与突触联系起来并控制复杂的星形胶质细胞结构。 基于这些观察结果和先前发表的结果，该提议将利用新颖且完善的技术来确定星形胶质细胞中的NLs如何调节突触相互作用并产生星形胶质细胞结构复杂性。通过结合细胞生物学、光学和电子显微镜以及电生理学，本提案的目的将测试 研究星形胶质细胞中的NLs，并鉴定星形胶质细胞-神经元接触和通过星形胶质细胞NLs的下游信号传导的分子机制。这一提议的结果将为研究整个发育过程中神经元和星形胶质细胞之间的相互作用和神经可塑性开辟令人兴奋的新途径。NLs与许多疾病状态相关，包括自闭症和癫痫。因此，拟议的工作将阐明需要重新评估这些CAM在整个三方突触。