Mechanisms of Axonal Degeneration in Traumatic Injury and Neurological Disease

描述(申请人提供)：轴突变性有助于糖尿病、青光眼和帕金森病的病理，是化疗的剂量限制副作用。它是一种主动调控的程序，类似于细胞凋亡，但其执行机制不同。控制轴突保存和破坏的细胞程序还不是很清楚，我们目前也没有防止这种退化的治疗方法。开发治疗或预防轴突变性的疗法可以显著提高上述疾病患者的生活质量，同时还可以减轻它们给我们的医疗保健系统带来的负担。目前已知有两个基因影响神经元中的轴突退化：Wlds和MAP激酶DLK。抑制DLK或其下游的JNK可显著延缓损伤模型的轴突变性。我建议研究由DLK控制的允许这种延迟的细胞机制。我将在体外培养原代体感神经元，在培养中损伤轴突，并使用细胞分析、共聚焦显微镜和生物化学来研究DLK如何调节微管、轴突运输和其他受轴突变性影响的途径。DLK和Wlds通路的交集也将被研究，因为这两种控制机制可能以相加的方式发挥作用，并可能为设计轴突变性的分子疗法提供额外的洞察力。为此，我们将使用已经建立的转基因小鼠和慢病毒感染的神经元在体外和体内。最后，我将测试DLK或JNK抑制是否控制组成视神经的视网膜神经节细胞(RGC)轴突的退化，因为这些轴突在青光眼期间经历退化。RGCs的体外研究和体内损伤模型，以及已建立的青光眼小鼠模型，都将被用来研究DLK和/或Wlds是否在这个系统中起到保护作用，以及抑制DLK通路是否可能是治疗青光眼的合适策略。由于轴突变性引起症状的疾病范围广泛，了解轴突变性将对公众健康有显著的好处。我们的研究试图确定延缓或预防轴突变性的有效途径，可用于临床环境。

DESCRIPTION (provided by applicant): Axon degeneration contributes to the pathologies of diabetes, glaucoma, and Parkinson's Disease, and is the dose-limiting side effect of chemotherapeutic treatments. It is an actively regulated program similar to apoptosis but distinct in its execution mechanisms. Cellular programs controlling the preservation and destruction of axons are not well understood, and we do not currently have therapies to prevent such degeneration. Development of therapies to treat or prevent axon degeneration could significantly improve the quality of life for patients with the above disorders while also reducing the burden they place on our health care system. Two genes are currently known to influence axon degeneration in neurons: Wlds, and the MAP kinase DLK. Inhibition of DLK or its downstream kinase JNK significantly delay axon degeneration in injury models. I propose to investigate the cellular mechanisms controlled by DLK that allow this delay. I will culture primary somatosensory neurons in vitro, injure axons in culture, and use cellular assays, confocal microscopy, and biochemistry to ask how DLK regulates microtubules, axon transport, and other pathways affected by axon degeneration. The intersection of the DLK and Wlds pathways will also be examined, as these two control mechanisms may act in an additive manner and could provide additional insight into designing molecular therapies for axon degeneration. For this aim we will use already established transgenic mice and lentiviral infection of neurons in vitro and in vivo. Finally, I will test whether DLK or JNK inhibition control degeneration in axons of retinal ganglion cells (RGCs) comprising the optic nerve, as these axons undergo degeneration during glaucoma. Both in vitro studies of RGCs and in vivo injury models, as well as established mouse models of glaucoma, will be used to ask whether DLK and/or Wlds exert protective effects in this system and whether DLK pathway inhibition may be an appropriate therapeutic strategy for glaucoma. Understanding axon degeneration will have significant public health benefits due to the broad spectrum of diseases where axon degeneration causes symptoms. Our research seeks to determine effective avenues for delay or prevention of axon degeneration that could be used in clinical settings