Respiratory Virus Induced Sensory Neuroplasticity

描述（由申请人提供）：呼吸道病毒感染会调节感觉神经系统，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；对其他人来说，这可能会发展为严重的发病率。事实上，病毒感染是儿童哮喘加重的主要原因，也是慢性阻塞性肺病加重的常见原因。病毒感染也被认为是慢性非生产性咳嗽的主要原因，据说有多达10%的人口受到影响。本研究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介质。在Aim 1中，我们特别讨论了我们的假设，该假设得到了初步数据的支持，即病毒感染导致迷走神经肺外a纤维的表型改变，使它们呈现c纤维伤害感受器样表型。我们将重点放在结节性肺外a纤维上，因为它们终止于大气道上皮下方（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。我们假设病毒感染诱导了a纤维神经元中配体门控离子通道TRPV1、TRPA1和嘌呤能受体的重新表达，使它们对通常不敏感的无数刺激产生反应。我们在单个识别神经元的基因表达水平上解决了这一假设。在Aim 2中，我们在功能水平上进一步解决了这一假设，包括电生理学上通过记录气管单个a¿神经末梢的动作电位放电，以及生理学上使用咳嗽反射作为结果。在Aims 3-4中，实验旨在解决病毒诱导的神经可塑性机制的假设，即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。我们采用模仿、药理拮抗策略，并利用我们最近验证的方法，通过将腺相关病毒-sh- rna递送到结节神经节，在体内沉默迷走感觉神经元中的基因表达，来解决我们的假设。我们的多学科方法的结果应该在提供关于气道感觉神经可塑性的新知识方面具有内在价值。该结果还将揭示呼吸道病毒感染的复杂病理生理学，并可能为限制病毒引起的哮喘、慢性阻塞性肺病和慢性咳嗽恶化提供新的治疗策略。

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.