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: 10392331
• 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 2023-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10392331
• 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; 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; base; 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; 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其正常功能至关重要。这些连接的中断