Respiratory Virus Induced Sensory Neuroplasticity

描述(申请人提供)：呼吸道病毒感染调节感觉神经系统，导致打喷嚏、喉咙痛、咳嗽、反射性分泌物和喘息。对许多人来说，这是一个自我限制的问题；对另一些人来说，这可能会发展成严重的发病率。在FAAC，病毒感染是导致儿童哮喘恶化的主要原因，也是COPD恶化的常见原因。病毒感染也被认为是慢性无效咳嗽的主要原因，据说影响多达10%的人口。这项建议的长期目标是更好地了解呼吸道病毒诱导的感觉神经调节的机制和媒介。在目标1中，我们具体阐述了我们的假设，并得到了初步数据的支持，即病毒感染导致迷走神经肺外A？纤维的表型变化，使它们呈现C纤维伤害性感受器样表型。我们关注肺外A纤维，是因为它们终止于大呼吸道的上皮之下(许多呼吸道病毒感染的靶细胞)，而且当它们被激活时，会导致咳嗽、反射性分泌物和支气管收缩。我们假设，病毒感染从头开始诱导A纤维神经元中配体门控离子通道TRPV1、TRPA1和嘌呤能受体的表达，使它们对无数通常不起作用的刺激产生反应。我们在单个识别神经元的基因表达水平上解决了这一假说。在目标2中，我们通过记录气管内单个A？神经末梢的动作电位放电，在电生理学和生理学上使用咳嗽反射作为结果，在功能水平上进一步解决这一假设。在AIMS中，3-4个实验旨在解决这样的假设，即病毒诱导的神经可塑性背后的机制涉及脑源性神经营养因子(BDNF/NT3)和/或胶质细胞源性神经营养因子配体(GFLS)分别与TrkB和GFR受体相互作用。我们使用模仿、药理拮抗的策略来解决我们的假设，并利用我们最近验证的方法，在体通过将腺相关病毒-sh-RNAs传递到结状神经节来沉默迷走感觉神经元中的基因表达。我们的多学科方法的结果在提供有关呼吸道感觉神经可塑性的新知识方面应该具有内在价值。这一结果还将揭示呼吸道病毒感染的复杂病理生理学，并可能为旨在限制哮喘、慢性阻塞性肺病和慢性咳嗽的病毒诱发加重的治疗提出新的治疗策略。

DESCRIPTION (provided by applicant): Respiratory virus infections modulate the sensory nervous system leading to sneezing, sore throat, coughing, reflex secretions and wheezing. For many this is a self-limiting problem; for others this can progress to significant morbidity. In fac, viral infections are the leading cause of asthma exacerbations in children, and are also a common cause of COPD exacerbation. Viral infections are also thought to be a leading cause of chronic unproductive cough that is said to affect as many as 10% of the population. The long-range goal of this proposal is to develop at a better understanding of the mechanisms and mediators involved in respiratory virus-induced sensory neuromodulation. In Aim 1 we specifically address on our hypothesis, supported by preliminary data, that viral infection leads to a phenotypic change in the vagal extrapulmonary A¿ fibers such they take on a C-fiber nociceptor-like phenotype. We focus on the nodose extrapulmonary A-fibers because they terminate just beneath the epithelium in large airways (the target cell in many respiratory virus infections) and because when they are activated it leads to coughing, reflex secretions and bronchoconstriction. We hypothesize that viral infections induce, de novo, the expression of the ligand-gated ion channels TRPV1, TRPA1, and purinergic receptors, in the A-fiber neurons rendering them responsive to myriad stimuli they would ordinarily be unresponsive to. We address this hypothesis at the level of gene expression in single identified neurons. In Aim 2 we further address this hypothesis at a functional level both electrophysiologically by recording action potential discharge from single A¿ nerve terminals in the trachea, and physiologically using the cough reflex as an outcome. In Aims 3-4 experiments are designed to address the hypothesis that the mechanisms underlying the viral-induced neuroplasticity involved brain-derived neurotrophic factor (BDNF/NT3) and/or glial cell-derived neurotrophic factor ligands (GFLs) interacting with the TRKB and GFR¿ receptors, respectively. We address our hypotheses using a strategy of mimicry, pharmacological antagonism and by making use of our recently validated method to silence gene expression in vagal sensory neurons in vivo with adeno-associated virus-sh-RNAs delivered to the nodose ganglion. The results from our multidisciplinary approach should be of intrinsic value in providing new knowledge regarding sensory neuroplasticity in the airways. The results will also shed new light on the complex pathophysiology of respiratory viral infections and possibly suggest new therapeutic strategies for treatment aimed at limiting viral evoked exacerbations of asthma, COPD, and chronic cough.