Dynamic regulation of SER during development and synaptic plasticity

发育和突触可塑性过程中 SER 的动态调节

• 批准号: 8701399
• 负责人: DEBORAH JEAN WATSON
• 金额: $ 5.7万
• 依托单位: UNIVERSITY OF TEXAS AT AUSTIN
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-01 至 2015-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8701399
• 关键词: AMPA Receptors; Adult; Age; Basic Science; Calcium; Carrying Capacities; Cell model; Collaborations; Complex; Dendrites; Dendritic Spines; Dependence; Development; Electron Microscopy; Elements; Equilibrium; Goals; Hippocampus (Brain); Hour; Indium; Knowledge; Laboratories; Learning; Light; Long-Term Potentiation; Membrane; Membrane Protein Traffic; Memory; Mission; Modeling; Modification; NMDA receptor antagonist; National Institute of Child Health and Human Development; National Institute of Mental Health; Neurons; Organelles; Outcome; Pattern; Perfusion; Phase; Phosphorylation; Process; Protein Biosynthesis; Proteins; Pyramidal Cells; Regulation; Relative (related person); Research; Research Proposals; Resolution; Resources; Role; Route; Science; Slice; Smooth Endoplasmic Reticulum; Specificity; Structure; Sum; Synapses; Synaptic plasticity; Testing; Time; Tubular formation; United States National Institutes of Health; Vertebral column; brain behavior; cognitive function; density; developmental disease; experience; in vivo; indexing; light microscopy; nanometer; postnatal; public health relevance; reconstruction; research study; synaptogenesis; therapeutic target

DESCRIPTION (provided by applicant): New research from a collaboration between the Harris and Ehlers laboratories shows that the mobility of cargo along the smooth endoplasmic reticulum (SER) of hippocampal dendrites is reduced where the SER is highly elaborated, particularly along spiny segments and at dendritic branch points. The primary objective of this research proposal is to investigate whether the SER network within developing dendrites is locally regulated in the vicinity of spines and synapses. We will examine changes in dendritic SER organization during a period of robust synaptogenesis from postnatal day (P) 15 to P21. During this one postnatal week, oblique dendrites mature substantially in spine number and synapse size. Aim 1 will examine how the dendritic SER accommodates new spine formation during normal development. We will test the hypothesis that the local organization of dendritic SER becomes more elaborate as spine density and synapse size increase from P15 to P21. To test this hypothesis, we will use the nanometer resolution of serial section electron microscopy to make three-dimensional (3D) reconstructions of dendrites, synapses, and the dendritic SER network of perfusion-fixed hippocampus in vivo at P15 and P21. To estimate an index of local elaboration, we will compare regions of SER that form complex SER cisterns to regions that mainly consist of simple tubules along spiny and spine-free segments of dendrites. We will also induce long-term potentiation (LTP) in hippocampal slices (as a cellular model of learning) to investigate changes in the organization of dendritic SER during synaptic plasticity. We will use theta-burst stimulation (TBS) to study multiple phases of LTP. The AMPA receptor-dependent, early-phase LTP (E-LTP) lasts up to an hour, while the protein-synthesis dependent, late- phase LTP (L-LTP) endures for more than 3 hrs. Aim 2 will test whether dendritic SER undergoes plasticity- dependent elaboration during E-LTP. Aim 3 will test the hypothesis that plasticity-dependent elaboration of dendritic SER is reduced during L-LTP relative to E-LTP. In these experiments, slices that received TBS (1 each for E-LTP and L-LTP) will be compared to a slice that only received control-stimulation. After expression of LTP, we will compare spine density and synapse size between control and TBS dendrites at P15 and P21, and evaluate whether the organization of the dendritic SER near spines is altered relative to the spine-free portions of the dendritic shaft in these slices. LTP-specific effects will be controlled for by administering APV, a competitive NMDA receptor antagonist known to block LTP. The implications of these findings will establish a comprehensive description of the role of SER in the development and plasticity of spines and synapses at a postnatal age where developmental disorders often manifest dendritic abnormalities. The goals put forth in this application serve the mission of a variety of NIH agencies that use basic research to understand the evolving science of brain, behavior, and experience (e.g., NIMH and NICHD) and will help to identify potential therapeutic targets for developmental disorders associated with malformed spines and dysfunctional SER.

描述（由申请人提供）：来自哈里斯和埃勒斯实验室之间的合作的新研究表明，在高度详细说明SER的情况下，沿着SER高度阐述的海马树突的光滑内质网（SER）的货物的移动性降低了，尤其是沿着Spiny片段和树突状分支点。该研究建议的主要目的是研究开发树突中的SER网络是否在刺和突触的附近受到本地调节。我们将在产后（P）15至P21的强大突触发生期间检查树突状组织的变化。在这个产后的一周中，倾斜的树突在脊柱数量和突触大小中基本上成熟。 AIM 1将检查树突状在正常发育过程中如何适应新的脊柱形成。我们将检验以下假设：随着脊柱密度和突触的大小从p15增加到p21，树突状Ser的局部组织变得更加详尽。为了检验这一假设，我们将使用串行截面电子显微镜的纳米分辨率来对树突，突触，突触和树突状Ser网络进行三维（3D）重建，该网络是在P15和P21的体内灌注固定海马的网络。为了估计局部详细说明的指数，我们将比较形成复杂的SER水箱的SER区域与主要由沿树突的刺和无脊柱段的简单小管组成的区域。我们还将在海马切片中诱导长期增强（LTP）（作为一种学习的细胞模型），以研究突触可塑性期间树突状Ser组织的变化。我们将使用theta-burst刺激（TBS）研究LTP的多个阶段。 AMPA受体依赖性的早期LTP（E-LTP）持续一个小时，而蛋白质合成依赖于晚期LTP（L-LTP）持续3个小时以上。 AIM 2将测试在E-LTP期间，树突状Ser是否经历了依赖性阐述。 AIM 3将检验以下假设：相对于E-LTP，在L-LTP期间，树突状Ser的塑性依赖性阐述会减少。在这些实验中，将比较接收TBS的切片（E-LTP和L-LTP 1）与仅接收控制刺激的切片。 LTP表达后，我们将在P15和P21处比较对照和TBS树突之间的脊柱密度和突触大小，并评估是否相对于无脊椎部分的棘突的组织是否改变了棘突。 这些切片中的树突轴。 LTP特异性效应将通过管理APV（已知可以阻止LTP的竞争性NMDA受体拮抗剂）来控制APV。这些发现的含义将对SER在产后时代的刺和突触的发展和突触的可塑性中的作用进行全面描述，在这些年龄中，发育障碍通常表现出树突状异常。本应用程序中提出的目标达到了各种NIH机构的使命，这些NIH机构使用基础研究来了解大脑，行为和经验的不断发展的科学（例如NIMH和NICHD），并将有助于确定与棘突和功能障碍性疾病相关的发育障碍的潜在治疗目标。