Pairing Modeling and Experiment to Understand Microtubule Behavior in Healthy and Injured Neurons

配对建模和实验以了解健康和受损神经元的微管行为

• 批准号: 10445753
• 负责人: Maria-Veronica Ciocanel
• 金额: $ 33.57万
• 依托单位: PENNSYLVANIA STATE UNIVERSITY, THE
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-06-21 至 2027-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10445753
• 关键词: Acute; Address; Architecture; Axon; Behavior; Biological Assay; Biophysical Process; Cells; Coupling; Cytoskeletal Modeling; Cytoskeleton; Dendrites; Development; Differential Equation; Drosophila genus; Equilibrium; Excision; Filament; Foundations; Generations; Genetic; Geometry; Growth; Health; Image; Individual; Injury; Markov Chains; Mathematics; Measurable; Measurement; Measures; Microtubules; Modeling; Natural regeneration; Neuronal Injury; Neurons; Outcome; Pattern; Regulation; Role; Selection Bias; Shapes; Stereotyping; System; Testing; Time; Validation; Work; axon injury; axon regeneration; base; cell injury; discrete time; experimental study; flexibility; in silico; in vivo; in vivo Model; in vivo evaluation; in vivo imaging; insight; mathematical methods; mathematical model; novel; predictive modeling; resilience; response; response to injury; theories

Project Summary Neurons rely on polarity and stability of the microtubule cytoskeleton to support long-range directed transport and long-term survival. However, both polarity and stability can be rapidly altered in response to injury and these rearrangements are critical for neuronal resilience. It is becoming clear that rather than a single master mechanism controlling neuronal microtubule organization through time and space, multiple mechanisms operate in parallel. This complexity makes it challenging to understand how each mechanism contributes to filament organization and how the system works as a whole. To overcome this challenge, a mathematical framework that incorporates known mechanisms will be built. This framework will be invaluable for understanding the dendrite microtubule system, and how it responds to perturbations induced by injury. Aim 1. Polarized organization of microtubules in neurons is critical for correct cargo delivery to axons and dendrites. A spatial stochastic model of the polarized array of dendritic microtubules will be constructed using known mechanisms of polarity control in Drosophila dendrites. This model will also incorporate known parameters for microtubule growth dynamics. Model validation will be carried out using experimental perturbations of polarity control mechanisms as well as using measurements of microtubule dynamics. This model will provide a framework for understanding how individual microtubule dynamics and local polarity mechanisms influence microtubule spatial organization and polarity. Aim 2. Neurons normally maintain the same polarized arrangement of microtubules for a lifetime. However, if the axon is removed, a dendrite can reverse polarity and become a regenerating axon. How polarity reversal occurs is not understood. The hypothesis that increased entry of microtubules from the cell body drives reversal will be tested in vivo and in silico. The role of other control mechanisms in polarity reversal will also be systematically addressed by testing the mathematical model and informing new experimental directions. Aim 3. Most neurons have several dendrites emerging from the cell body. After axon damage, only one dendrite switches polarity whereas the others revert to their pre-injury orientation. This selection bias is hypothesized to depend on branching patterns of the dendrites. The combination of axon removal experiments in neurons with distinct branching features and a reduced mathematical description of microtubule behavior will provide insights on how dendrite geometry influences polarity control, robustness, and regeneration. The combination of sophisticated live imaging of microtubules in neurons in vivo with new mathematical modeling of microtubule behavior will drive new insights on how neurons maintain a polarized, yet dynamic and flexible microtubule cytoskeleton for a lifetime. The challenges posed by axonal injury require radical cytoskeletal reorganization. Models developed and validated with measurements from healthy neurons will be used to gain deep understanding of microtubule control mechanisms that are critical for axonal regeneration.

项目摘要 神经元依赖于微管细胞骨架的极性和稳定性来支持长距离定向的 运输和长期生存。然而，极性和稳定性都可以响应于 损伤和这些重排对于神经元恢复力是至关重要的。越来越清楚的是， 通过时间和空间控制神经元微管组织的单一主机制， 机制并行运行。这种复杂性使得理解每种机制 有助于细丝组织和系统如何作为一个整体工作。为了克服这一挑战，A 将建立包含已知机制的数学框架。这一框架将是非常宝贵的 了解树突微管系统，以及它如何响应损伤引起的扰动。 目标1。神经元中微管的极化组织对于将货物正确递送到轴突和神经元中至关重要。 树突一个树突状微管极化阵列的空间随机模型将被构建， 果蝇树突极性控制的已知机制。该模型还将结合已知的 微管生长动力学参数。模型验证将使用实验 极性控制机制的扰动以及使用微管动力学的测量。这 模型将为理解个体微管动力学和局部极性 机制影响微管的空间组织和极性。 目标二。神经元在正常情况下会终生保持微管的极化排列。但如果 轴突被移除，树突可以反转极性并成为再生轴突。极性逆转 发生的事情不理解。假设增加微管从细胞体进入 将在体内和计算机模拟中测试逆转。其他控制机制在极性反转中的作用也将被讨论。 通过测试数学模型和通知新的实验方向来系统地解决。 目标3.大多数神经元有几个树突从细胞体中出现。轴突受损后，只有一个 枝晶切换极性，而其它枝晶恢复到它们的损伤前取向。这种选择偏差是 假设依赖于树突的分支模式。轴突移除实验 在具有明显分支特征和微管行为的简化数学描述的神经元中， 提供有关枝晶几何形状如何影响极性控制、鲁棒性和再生的见解。 结合复杂的活的成像微管在体内神经元与新的数学 微管行为的建模将推动对神经元如何保持极化的新见解，但动态， 灵活的微管细胞骨架。轴突损伤带来的挑战需要彻底的 细胞骨架重组通过健康神经元的测量结果开发和验证的模型将在 用于深入了解对轴突再生至关重要的微管控制机制。