MOLECULAR DISSECTION OF THE AXONAL INJURY RESPONSE FOR REGENERATION AND NEUROPROTECTION

轴突损伤再生和神经保护反应的分子解剖

• 批准号: 9973607
• 负责人: Trent Watkins
• 金额: $ 37.6万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 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 2025-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/9973607
• 关键词: Acute; Address; Adult; Afferent Neurons; Alzheimer' s Disease; Apoptosis; Apoptotic; Axon; Axotomy; Binding; Cells; Cellular Stress Response; Complex; Data; Disease; Dissection; Drug Targeting; Engineering; Exhibits; Failure; Feedback; Functional disorder; Gene Expression; Genes; Genetic; Genetic Transcription; Glaucoma; Goals; In Vitro; Injury; Intervention; JUN gene; Knockout Mice; Laboratories; Leucine Zippers; MAP Kinase Modules; Mediating; Mediator of activation protein; 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; 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; base; biological adaptation to stress; chemotherapy induced neuropathy; conditional knockout; experimental study; functional restoration; improved; in vitro Model; in vivo; in vivo evaluation; injured; insight; knock-down; loss of function; neuron apoptosis; neuron loss; neuronal survival; neuroprotection; novel; novel therapeutics; overexpression; preservation; programs; regenerative; repaired; response; response to injury; retinal neuron; screening; 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正常功能是必不可少的。这些连接的中断 在从脊髓损伤到青光眼到化疗引起的神经病变的损伤中， 使人虚弱尽管轴突再生的内在能力为PNS的恢复提供了希望，但它在PNS中的失败， CNS，沿着损伤诱导的神经变性，经常导致永久性缺陷。我们的实验室旨在 了解神经元如何对轴突损伤作出反应，目的是调节这种反应，以改善轴突 再生和神经元存活。在目前的建议中，我们利用我们最近发现的一种 轴突损伤反应的第二个意外分支，这一通路也与正常记忆有关 形成和神经退行性疾病。了解这一途径的影响，称为 综合应激反应（ISR），在PNS和CNS轴突损伤的易处理模型中的修复和存活 可能有助于目前正在探索的用于各种病症的基于ISR的疗法。此前，我们和其他 已经证明，轴突再生和神经变性都依赖于一个主调节器， 轴突损伤反应称为双亮氨酸拉链激酶（DLK）。损伤诱导的DLK激活导致 多方面的转录反应，主要通过启动一个众所周知的MAP激酶（MAPK） 信号级联没想到，我们最近发现，DLK也是有必要和充分从事 的ISR。DLK应答的MAPK和ISR分支如何相互作用以定义差异凋亡的细胞因子？ 以及CNS和PNS中受损神经元的再生命运？我们正在努力解决这个问题 已经聚集在ISR的主要下游效应物之一，转录激活因子4上 （ATF 4），作为再生和凋亡的潜在调节剂。我们的初步证据显示 ATF 4可能对CNS和PNS的再生潜力产生不同的影响。同时，我们发现， 抑制ISR可减少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ATF 4或从ISR的其他方面。了解ATF 4在ISR和 更广泛的DLK反应，我们建议将体外方法与体内CNS和PNS损伤模型联合收割机结合。 首先，为了理解ISR抑制的神经保护作用，我们将确定ATF 4对基因表达的特异性贡献。 表达变化和体内CNS中的神经元损失。其次，我们将测试ISR的体内作用， ATF 4在周围神经损伤和视神经损伤后轴突再生中的作用，后者在神经损伤后轴突再生中的作用。 结合部分克服CNS再生失败的操作。第三，发现 为了研究ATF 4调控轴突再生的机制，我们将测试ATF 4与其 推定的结合伴侣，上游介质，和下游目标，在我们建立的体外模型。这些 研究将揭示DLK反应的ISR-ATF 4轴在决定轴突再生中的作用， 神经变性，告知这些目标在轴突病和其他病症中的治疗潜力。