Traumatic axonal injury in the visual system: role of dual leucine zipper kinase

视觉系统外伤性轴突损伤：双亮氨酸拉链激酶的作用

• 批准号: 9895809
• 负责人: VASSILIS E. KOLIATSOS
• 金额: $ 50.96万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-04-01 至 2022-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9895809
• 关键词: Acceleration; Atrophic; Axon; Axotomy; Blindness; Blood; Brain; CRISPR/Cas technology; Cell Death; Cessation of life; Clinical Services; Clustered Regularly Interspaced Short Palindromic Repeats; Communities; Crush Injury; Data; Denervation; Diffuse; Drug Targeting; Enzymes; FDA approved; Foundations; Functional disorder; Genes; Genetic; Impairment; Incidence; Individual; Injury; Knock-out; Knockout Mice; Label; Laboratories; Lesion; Leucine Zippers; Location; LoxP-flanked allele; MAPK8 gene; Mediator of activation protein; Methods; Modeling; Molecular; Mus; Nerve Crush; Nerve Degeneration; Neuroanatomy; Neurons; Optic Nerve; Optic Nerve Injuries; Optic tract structure; Outcome; Pathway interactions; Pharmacology; Phosphotransferases; Preparation; Presynaptic Terminals; Resolution; Retinal Ganglion Cells; Rodent; Role; Rotation; Severities; Signal Pathway; Signal Transduction; Signaling Molecule; System; Testing; Therapeutic; Therapeutic Effect; Time; Tracer; Transgenic Organisms; Traumatic Brain Injury; Visual; Visual Acuity; Visual system structure; Work; axon injury; axonal degeneration; axonopathy; base; behavior measurement; brain tissue; cell injury; clinically relevant; conditional knockout; design; drug development; experimental study; genome editing; inhibitor/antagonist; injured; kinase inhibitor; mechanical force; medical attention; member; neuropathology; novel; novel therapeutics; prevent; protective effect; relating to nervous system; response; retinal ganglion cell degeneration; retinotectal; superior colliculus Corpora quadrigemina

PROJECT SUMMARY Traumatic brain injury (TBI) is a very common problem with over 2 million new cases requiring medical attention annually in the US. A neuropathology that is widely shared among various types of TBI and across spectrum of severity is diffuse or traumatic axonal injury (TAI), a form of ultra-rapid deformation and disruption of axons caused by rotational acceleration and shearing of brain tissue. In this project we use a visual model of TAI and explore the hypothesis that the DLK-JNK signaling cascade, known to be activated in simple axotomy lesions like nerve crush, triggers downstream degenerative effects of TAI in neurons projecting in the optic nerve, i.e. retinal ganglion cells (RGCs). We ask three questions, in logical order: is DLK-JNK pathway activated in visual TAI? If so, does DLK-JNK activation trigger retrograde degenerative effects in RGCs as in simple axotomy models? And does blocking of the DLK-JNK pathway prevent or treat RGC degeneration and related system impairments such as disconnection with CNS targets and loss of vision? To inflict TBI, we use the impact acceleration model of diffuse TAI with which we have consistently produced primary optic nerve injury in our laboratories. Our experimental subjects are conditional knockout mice for key members of the dual leucine zipper kinase (DLK-JNK) cascade. We also employ CRISPR strategies to disrupt the initiating kinases of the DLK-JNK cascade, DLK and LZK, and also treat wild-type injured mice with the DLK inhibitor sunitinib. Our experimental readouts include kinase activation, cell death, axonal and terminal degeneration using conventional and high-resolution (CLARITY) neuroanatomical methods, and behavioral measures of visual acuity. Besides exploring the role of key members of the DLK-JNK signaling pathway in perikaryal and axonal degeneration in visual TAI, the proposed experiments provide proof of concept for the protective or therapeutic effect of DLK/LZK blockade in TAI. The project leverages the complementary strengths of our laboratories and the design and experimental methods are supported by extensive preliminary studies. In Specific Aim 1 that serves as the foundation of the proposal, we will determine whether TAI in the visual system is associated with activation of the DLK-JNK signaling cascade in RGCs and we will identify key signaling molecules. In Specific Aim 2, we will explore whether blocking JNK and DLK/LZK signaling with knockout/genome editing strategies or pharmacological inhibition prevents or aborts RGC perikaryal and axonal degeneration in visual TAI. In Specific Aim 3, we will determine whether blocking DLK/LZK activation with knockout/genome editing strategies or pharmacological approaches prevents or aborts neural system impairments (visual disconnection and dysfunction). Taken together, these experiments examine the role of the DLK-JNK pathway in neuronal degeneration, disconnection, and dysfunction following TAI in a model CNS system and explore novel protective and therapeutic strategies for diffuse TBI.

项目摘要 创伤性脑损伤（TBI）是一个非常普遍的问题，超过200万个新病例需要医疗 每年在美国注意。一种神经病理学，在各种TBI和整个TBI中广泛共享 严重程度的频谱是弥漫性或创伤性轴突损伤（TAI），这是一种超优化变形和破坏的形式 由旋转加速度和脑组织剪切引起的轴突。在这个项目中，我们使用了一个视觉模型 TAI并探讨了以下假设：DLK-JNK信号级联（已知在简单的轴切开术中被激活） 诸如神经挤压，诸如神经压伤之类的病变，触发TAI在光学上投射的神经元中的下游退化效应 神经，即视网膜神经节细胞（RGC）。我们以逻辑顺序提出三个问题：是DLK-JNK途径 在Visual Tai中激活？如果是这样，DLK-JNK激活是否触发RGC中的逆行退行效应 简单的轴切割模型？并阻止DLK-JNK途径预防或治疗RGC变性和 相关的系统障碍，例如与CNS目标断开连接和视力丧失？为了造成TBI，我们使用 弥漫性TAI的撞击加速度模型，我们一直在使用它产生主要的视神经 我们的实验室受伤。我们的实验主题是双重主要成员的有条件敲除小鼠 亮氨酸拉链激酶（DLK-JNK）级联。我们还采用CRISPR策略来破坏引发激酶 DLK-JNK Cascade，DLK和LZK，还用DLK抑制剂苏尼替尼治疗野生型受伤的小鼠。 我们的实验读数包括激活激活，细胞死亡，轴突和末端变性 常规和高分辨率（清晰度）神经解剖学方法以及视觉的行为度量 敏锐度。除了探索DLK-JNK信号传导途径的主要成员的角色和轴突的角色 Visual Tai的变性，提出的实验为保护性或治疗性提供了概念证明 TAI中DLK/LZK封锁的效果。该项目利用了我们实验室的互补优势 广泛的初步研究支持了设计和实验方法。在特定目标1中 作为提案的基础，我们将确定视觉系统中的TAI是否与 RGC中DLK-JNK信号级联的激活，我们将确定关键信号分子。具体 AIM 2，我们将探索使用淘汰/基因组编辑策略阻止JNK和DLK/LZK信号传导 或药理学抑制可防止或中止视觉TAI中的RGC周期和轴突变性。在 特定目标3，我们将确定是否通过敲除/基因组编辑阻止DLK/LZK激活 策略或药理学方法可以防止或流产神经系统障碍（视觉断开连接 和功能障碍）。综上所述，这些实验检查了DLK-JNK途径在神经元中的作用 TAI在模型CNS系统中的TAI之后的变性，断开和功能障碍并探索新颖 弥漫性TBI的保护和治疗策略。