Eosinophil Mechanisms of Sensory Neuroplasticity in a Murine Model of Asthma

描述(申请人提供)：哮喘是一种慢性肺部炎症性疾病，是一种严重的健康负担。尽管适当使用哮喘药物可以成功地减少损害，但它们不会减缓病情发展，并有可能增加病情恶化的风险。哮喘也是一种具有多种病理特征和治疗耐药亚型的异质性疾病。以下项目旨在深入了解感觉神经可塑性，或感觉神经元在哮喘中的变化，这是一个确定的治疗目标和有用的工具，以表征哮喘亚型。哮喘时呼吸道感觉神经元功能障碍并引起气道高反应性。由于呼吸道神经支配的特征障碍，感觉障碍背后的神经元结构和刺激因素的上游变化尚不清楚。在目前的项目中，开发了一种新的方法，允许对整个呼吸道的神经支配进行可视化，并对神经分支和神经密度进行计算机量化。我们已经证明，呼吸道中嗜酸性粒细胞的增加会导致神经分支点和长度加倍。这项研究的长期目标是将这项技术与转基因、体外和分子方法结合使用，以表征和了解哮喘相关的感觉神经可塑性。在类似疾病的数据和初步数据的指导下，目前的项目将测试两种哮喘模型中感觉神经元的分支和密度是否通过嗜酸性粒细胞增加，以及分支生长是否与感觉神经诱导的反射性支气管收缩增加相关。初步数据已经证明了其中的一些变化。该项目随后将研究嗜酸性粒细胞衍生神经营养因子在产生哮喘相关感觉神经可塑性中的作用。目前的项目将使用几种哮喘的小鼠模型，包括1。白蛋白致敏和激发模型，2)缺乏嗜酸性粒细胞的转基因小鼠，以及3.转基因小鼠表现出过多的肺嗜酸性粒细胞。对于第一个目标，呼吸道神经分支和长度将通过计算神经模型进行量化，并与功能读数(反射性支气管收缩)进行比较。第二个目的是利用共培养系统研究嗜酸性粒细胞神经营养因子(NGF、BDNF、NT-3、NT-4)释放对感觉神经可塑性的影响。嗜酸性粒细胞和感觉神经元的混合培养将与外源性神经营养因子和神经营养因子阻断抗体一起使用，随后将对神经元分支生长进行量化。 公共卫生相关性：目前的提案将利用一种新的技术来调查呼吸道感觉神经元的生长作为哮喘的原因，哮喘是一种常见的炎症性肺部疾病。这项工作将有助于了解哮喘的发病机制，并寻找新的治疗靶点。

DESCRIPTION (provided by applicant): Asthma is a chronic inflammatory disease of the lung and a significant health burden. Although appropriate usage of asthma medications successfully reduces impairment they do not slow progression and potentially increase risk of exacerbation. Asthma is also a heterogenous disease with various pathologic features and treatment-resistant subtypes. The following project aims to offer insight into sensory neuroplasticity, or how sensory neurons change in asthma, which is an established therapeutic target and useful tool to characterize asthma subtypes. Airway sensory neurons in asthma malfunction and cause airway hyperreactivity. The upstream changes to neuron structure and inciting factor behind sensory dysfunction are unknown due to obstacles in characterizing airway innervation. For the current project a novel method was developed permitting the visualization of whole airway innervation and computerized quantification of nerve branching and nerve density. We have shown that increased eosinophils in the airway results in a doubling of nerve branchpoints and length. The long term goal of this research is to use this technique in tandem with transgenic, in vitro, and molecular approaches to characterize and understand asthma-related sensory neuroplasticity. Guided by data from similar diseases and preliminary data, the current project will test if sensory neuron branching and density increases via eosinophils in two asthma models and if branched outgrowth correlates with increased sensory nerve-induced reflex bronchoconstriction. Preliminary data has already demonstrated some of these changes. This project will subsequently investigate the role of eosinophil-derived neurotrophins in producing asthma-related sensory neuroplasticity. The current project will use several mouse models of asthma including 1.) an valbumin sensitization and challenge model, 2.) transgenic mice lacking eosinophils, and 3.) transgenic mice exhibiting overabundant lung eosinophils. For the first aim, airway nerve branching and length will be quantified with computational nerve modeling and compared to a functional readout, that of reflex bronchoconstriction. The second aim is to investigate the role of eosinophil neurotrophin (NGF, BDNF, NT-3, NT-4) release on sensory neuroplasticity using a co-culture system. Eosinophil and sensory neuron co-cultures will be used with exogenous administration of neurotrophins, and neurotrophin blocking antibodies followed by quantification of neuron branched outgrowth. PUBLIC HEALTH RELEVANCE: The current proposal will utilize a novel technique to investigate outgrowth of airway sensory neurons as a cause of asthma, a common inflammatory lung disease. This work will aid in understanding asthma pathogenesis and identifying new therapeutic targets.