Molecular Dissection of the Axonal Injury Response for Regeneration and Neuroprotection

轴突损伤反应再生和神经保护的分子解剖

• 批准号: 10817383
• 负责人: Trent Watkins
• 金额: $ 37.95万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-04-01 至 2025-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10817383
• 关键词: Acute; Address; Adult; Afferent Neurons; Alzheimer' s Disease; Apoptosis; Apoptotic; Axon; Axotomy; Binding; Cells; Cellular Stress; Complex; Data; Disease; Dissection; Drug Targeting; Engineering; Exhibits; Failure; Feedback; Functional disorder; Gene Expression; Genes; Genetic; Genetic Transcription; Glaucoma; Goals; In Vitro; Induction of Apoptosis; Injury; Intervention; JUN gene; Knockout Mice; Laboratories; Leucine Zippers; MAP Kinase Modules; Mediating; Mediator; Memory; Mitogen-Activated Protein Kinases; Modeling; Molecular; Mus; Natural regeneration; Nerve Crush; Nerve Degeneration; Neurodegenerative Disorders; Neuronal Injury; Neurons; Optic Nerve; Optic Nerve Injuries; Optics; Outcome; Pathology; Pathway interactions; Peripheral Nervous System Diseases; Peripheral nerve injury; Phosphotransferases; Play; Recovery; Regenerative response; Regulation; Role; Sensory; Signal Transduction; Small Interfering RNA; Spinal cord injury; Stress; Testing; Therapeutic; Translations; Trauma; Up-Regulation; activating transcription factor 4; aged; arm; axon growth; axon injury; axon regeneration; axonopathy; biological adaptation to stress; chemotherapy induced neuropathy; conditional knockout; experimental study; functional restoration; improved; in vitro Model; in vitro regeneration; in vivo; in vivo evaluation; injured; insight; knock-down; loss of function; nerve damage; neuron apoptosis; neuron loss; neuronal survival; neuroprotection; novel; novel therapeutics; overexpression; preservation; programs; regeneration potential; regenerative; repaired; response; response to injury; retinal neuron; screening; single nucleus RNA-sequencing; transcription factor

The axonal connections between neurons are essential for their proper function. Disruption of these connections in insults ranging from spinal cord injury to glaucoma to chemotherapy-induced neuropathy are frequently debilitating. Whereas intrinsic capacity for axon regeneration offers hope for recovery in the PNS, its failure in the CNS, along with injury-induced neurodegeneration, frequently results in permanent deficits. Our lab aims to understand how neurons respond to axon injuries, with the goal of modulating this response for improved axon regeneration and neuronal survival. In the current proposal, we capitalize on our recent discovery of an unexpected second branch of the axonal injury response, a pathway that is also implicated in normal memory formation and in neurodegenerative diseases. Understanding the impact of this pathway, known as the Integrated Stress Response (ISR), on repair and survival in the tractable models of PNS and CNS axonal injury may facilitate ISR-based therapies currently being explored for a variety of conditions. Previously, we and others have demonstrated that both axon regeneration and neurodegeneration depend on a master regulator of the axonal injury response known as the Dual Leucine-zipper Kinase (DLK). Injury-induced DLK activation leads to a multifaceted transcriptional response, primarily through the initiation of a well-known MAP kinase (MAPK) signaling cascade. Unexpectedly, we recently discovered that DLK is also necessary and sufficient to engage the ISR. How do the MAPK and ISR branches of the DLK response interact to define the differential apoptotic and regenerative fates of injured neurons in the CNS and PNS? Our ongoing efforts to address this question have converged on one of the principal downstream effectors of the ISR, the Activating Transcription Factor 4 (ATF4), as a potential regulator of both regeneration and apoptosis. Our preliminary evidence suggests that ATF4 may differentially impact regenerative potential in the CNS and PNS. In parallel, we have found that inhibition of the ISR reduces neurodegeneration in a CNS model, though it is not yet known whether this results from reduced ATF4 or from other aspects of the ISR. To understand the role of ATF4 within the ISR and within the broader DLK response, we propose to combine in vitro approaches with in vivo CNS and PNS injury models. First, to understand neuroprotection by ISR inhibition, we will determine the specific contribution of ATF4 to gene expression changes and neuronal loss in the CNS in vivo. Secondly, we will test the in vivo roles of the ISR and ATF4 in axon regeneration following peripheral nerve injury and following optic nerve injury, the latter in combination with manipulations that partially overcome CNS regenerative failure. Thirdly, to discover mechanisms by which ATF4 regulates axon regeneration, we will test the genetic interactions of ATF4 with its putative binding partners, upstream mediators, and downstream targets in our established in vitro model. These studies will expose the roles of the ISR-ATF4 axis of the DLK response in determining axon regeneration and neurodegeneration, informing the therapeutic potential of these targets in axonopathies and other conditions.

神经元之间的轴突连接对于它们的适当功能至关重要。这些连接的破坏 从脊髓损伤到青光眼到化学疗法引起的神经病的侮辱，经常是 使人衰弱。轴突再生的内在能力为PNS恢复提供了希望 中枢神经系统以及损伤引起的神经变性，经常导致永久性缺陷。我们的实验室旨在 了解神经元如何应对轴突损伤，目的是调节此反应以改善轴突 再生和神经元生存。在当前的建议中，我们利用了最近发现的 轴突损伤反应的意外第二个分支，这一途径也与正常记忆有关 形成和神经退行性疾病。了解这一途径的影响，称为 综合应力响应（ISR），关于PNS和CNS轴突损伤的可拖动模型的修复和存活 可能会促进目前正在针对各种疾病探索的基于ISR的疗法。以前，我们和其他人 已经证明轴突再生和神经退行性都取决于 轴突损伤反应称为双亮氨酸Zipper激酶（DLK）。受伤引起的DLK激活导致 多方面的转录响应主要是通过众所周知的MAP激酶（MAPK）的启动 信号级联。出乎意料的是，我们最近发现DLK也足以参与。 ISR。 DLK响应的MAPK和ISR分支如何相互作用以定义差异凋亡 中枢神经系统和PN中受伤的神经元的再生命运？我们正在进行的解决这个问题的努力 已经收敛于ISR的主要下游效应子之一，即激活转录因子4 （ATF4），作为再生和凋亡的潜在调节剂。我们的初步证据表明 ATF4可能会差异地影响中枢神经系统和PN的再生潜力。同时，我们发现 ISR的抑制会降低CNS模型中的神经变性，尽管尚不清楚这是否会导致 从减少的ATF4或ISR的其他方面。了解ATF4在ISR和内部的作用 我们建议更广泛的DLK响应将体外方法与体内CNS和PNS损伤模型相结合。 首先，要通过ISR抑制了解神经保护，我们将确定AT​​F4对基因的特定贡献 CNS体内中枢神经系统的表达变化和神经元丧失。其次，我们将测试ISR的体内角色和 外周神经损伤和视神经损伤后的轴突再生中的ATF4，后者在 结合部分克服CNS再生失败的操作。第三，发现 ATF4调节轴突再生的机制，我们将测试ATF4与ITS的遗传相互作用 我们已建立的体外模型中推定的结合伙伴，上游介体和下游目标。这些 研究将揭示DLK响应的ISR-ATF4轴的作用在确定轴突再生和 神经变性，在轴突病和其他疾病中为这些靶标的治疗潜力告知。