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

基本信息

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
项目类别：
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&apos 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

项目摘要

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其正常功能至关重要。这些连接的中断从脊髓损伤到青光眼再到化疗引起的神经病变，这些损伤经常发生使人衰弱。虽然轴突再生的内在能力为 PNS 的恢复提供了希望，但它的失败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。我们实验室的目标是了解神经元如何对轴突损伤做出反应，目的是调节这种反应以改善轴突再生和神经元存活。在当前的提案中，我们利用了我们最近发现的轴突损伤反应的意外第二个分支，该途径也与正常记忆有关形成和神经退行性疾病。了解这条途径的影响，称为综合应激反应 (ISR)，关于 PNS 和 CNS 轴突损伤易处理模型的修复和生存可能会促进目前正在探索的针对多种病症的基于 ISR 的疗法。此前，我们和其他人已经证明轴突再生和神经变性都依赖于神经元的主调节器轴突损伤反应称为双亮氨酸拉链激酶 (DLK)。损伤引起的 DLK 激活导致多方面的转录反应，主要是通过众所周知的 MAP 激酶 (MAPK) 的启动信号级联。没想到最近我们发现DLK对于搞事情也是必要且充分的情监侦。 DLK 反应的 MAPK 和 ISR 分支如何相互作用来定义细胞凋亡的差异以及中枢神经系统和三七总神经系统中受损神经元的再生命运？我们正在努力解决这个问题已汇聚到 ISR 的主要下游效应器之一，即激活转录因子 4 (ATF4)，作为再生和细胞凋亡的潜在调节剂。我们的初步证据表明 ATF4 可能对 CNS 和 PNS 的再生潜力产生不同的影响。与此同时，我们发现抑制 ISR 可减少中枢神经系统模型中的神经退行性变，尽管尚不清楚这是否会导致来自减少的 ATF4 或来自 ISR 的其他方面。了解 ATF4 在 ISR 和内部的作用为了更广泛的 DLK 反应，我们建议将体外方法与体内 CNS 和 PNS 损伤模型相结合。首先，为了了解 ISR 抑制的神经保护作用，我们将确定 ATF4 对基因的具体贡献体内中枢神经系统的表达变化和神经元损失。其次，我们将测试 ISR 和 ISR 的体内作用 ATF4 在周围神经损伤和视神经损伤后轴突再生中的作用，后者在与部分克服中枢神经系统再生障碍的操作相结合。第三，发现 ATF4 调节轴突再生的机制，我们将测试 ATF4 与其基因的相互作用我们建立的体外模型中推定的结合伙伴、上游介体和下游靶标。这些研究将揭示 DLK 反应的 ISR-ATF4 轴在决定轴突再生和神经退行性变，揭示这些靶点在轴突病和其他疾病中的治疗潜力。