The influence of axonal ER on retrograde synapse loss following axon damage

轴突 ER 对轴突损伤后逆行突触损失的影响

• 批准号: 9894123
• 负责人: ANNE MARION TAYLOR
• 金额: $ 41.34万
• 依托单位: XONA MICROFLUIDICS, LLC
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-04-01 至 2023-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9894123
• 关键词: ATP2A2; Acute; Affect; Amines; Axon; Axotomy; Ca(2+)-Transporting ATPase; Calcium; Calcium Channel; Calcium Oscillations; Calcium Signaling; Cell Death; Communication; Corticospinal Tracts; Cytosol; Data; Dendrites; Dendritic Spines; Development; Distal; Endoplasmic Reticulum; Event; Foundations; Future; Gene Expression Profiling; Genes; Genetic Transcription; Glutamates; Goals; Heat shock proteins; Hippocampus (Brain); Human; Image; In Vitro; Inhibitory Synapse; Injury; Investigation; Knowledge; Lead; Measures; Mediating; Methods; Microfluidic Microchips; Microfluidics; Microtubules; Modeling; Molecular; Molecular Target; Mus; Nervous System Trauma; Neuronal Injury; Neurons; Partner in relationship; Pharmacology; Presynaptic Terminals; Proteins; Psyche structure; Pyramidal Cells; Pyramidal Tracts; Rattus; Reporter; Research; Role; Signal Pathway; Signal Transduction; Site; Sodium-Calcium Exchanger; Specificity; Stains; Stroke; Surgical incisions; Synapses; Synaptic Vesicles; Testing; Therapeutic; Time; Traumatic Brain Injury; Work; axon injury; base; biological adaptation to stress; density; differential expression; endoplasmic reticulum stress; hippocampal pyramidal neuron; human stem cells; immunocytochemistry; improved; in vivo; nerve injury; nervous system disorder; neuronal cell body; novel; postsynaptic; prevent; regenerative; response to injury; stroke patient; tool; vesicular release

Axon injury is an early event of neurotrauma that leads to retrograde cellular changes, including somatic ER stress, synapse loss, hyper-excitability, and even cell death. Foundational work remains needed to understand how axon-to-soma injury signals propagate to effect these profound retrograde changes in long projection pyramidal cells. Understanding this signaling is critical for the future development of neuroprotective approaches. Axon injury causes massive influx of calcium into the cytosol to initiate axon-to-soma signaling, leading to transcription-dependent retrograde synapse loss and hyperexcitability. Evidence suggests either an endoplasmic reticulum (ER)-dependent calcium wave or calcium-primed microtubule-based transport mediates this long-range axon-to-soma signaling. A vast ER network extends throughout the neuron from distal axon terminals to dendritic spines, influencing the availability of calcium, but the extent of axonal ER involvement in axon injury-induced synapse loss and hyper-excitability remains unknown. Further, while rat injury models are a mainstay of this research, it remains unclear how human glutamatergic neurons, with their diminished regenerative capacity, differ in their injury signaling mechanisms. Experimentally tractable multi-compartment, microfluidic chambers enable manipulation of axons independently from somata and dendrites, providing an important tool to investigate axon-to-soma communication in both murine and human stem cell-derived neurons. We found that hippocampal pyramidal neurons subjected to distal axotomy in our microfluidic chambers undergo somatic ER stress, retrograde synapse loss, and hyper-excitability. Reducing calcium influx locally at the site of injury and blocking transcription prevents axotomy-induced dendritic spine loss; thus, calcium signaling and rapid transcription mediate synapse loss following axon injury. Our long-term goal is to identify key molecular players and their timing of action that cause retrograde synapse loss and hyper-excitability following axon injury. Aim 1 will determine the influence of axonal ER on axotomy-induced somatic ER stress in both rat and human glutamatergic neurons. Aim 2 will examine the influence of axonal ER signaling on axotomy-induced synapse loss and hyper-excitability. Together, this study provides a critical first step in defining the role of ER during axon-to-soma injury signaling in pyramidal cells. Further, this project may lead to the novel identification of therapeutics during early stages of neuron damage and will likely have broader implications for other neurological disorders where both ER stress and axon damage are prevalent.

轴突损伤是神经瘤的早期事件，导致逆行细胞变化，包括体细胞ER 压力，突触丧失，超出性能甚至细胞死亡。基本工作仍然需要了解 轴突到肌瘤的损伤如何传播以实现长投影的这些深刻的逆行变化 锥体细胞。了解该信号对于神经保护的未来发展至关重要 方法。轴突损伤会导致钙大量流入细胞质中，以引发轴突到膜的信号传导， 导致转录依赖性逆行突触丧失和过度兴奋。有证据表明 内质网（ER）依赖性钙波或基于钙的微管介导 这种远程轴突到膜的信号传导。巨大的ER网络从远端轴突延伸到整个神经元 树突状刺的末端，影响钙的可用性，但轴突ER参与的程度 轴突损伤引起的突触丧失和超级启动性仍然未知。此外，大鼠损伤模型是 这项研究的主要支柱，尚不清楚人类谷氨酸能神经元如何减少 再生能力，其伤害信号传导机制有所不同。实验可拖动的多室， 微流体腔室可独立于Somata和树突对轴突进行操纵，提供 研究鼠和人类干细胞衍生的神经元中轴突对 - 瘤通信的重要工具。 我们发现，在微流体室进行远端轴切开术的海马锥体神经元发生 体细胞应力，逆行突触丧失和高兴趣。在本地减少钙涌入的位置 损伤和阻塞转录可防止轴切开术引起的树突状脊柱丧失；因此，钙信号传导和 快速转录介导轴突损伤后突触损失。我们的长期目标是确定关键分子 轴突受伤后导致逆行突触丧失和超出性能的球员及其动作时间。 AIM 1将确定轴突ER对大鼠和人的轴突切开术诱导的体细胞应激的影响 谷氨酸能神经元。 AIM 2将检查轴突ER信号传导对轴突造成的突触的影响 损失和超出性。这项研究共同为定义ER的作用提供了关键的第一步 锥体细胞中的轴突损伤信号传导。此外，该项目可能导致对 在神经元损害的早期阶段的治疗剂，可能会对其他 ER应力和轴突损伤都普遍存在的神经系统疾病。