Exacerbation of pertussis airway inflammation and pathology by pertussis toxin

描述(申请人提供)：百日咳(百日咳)是一种人类呼吸道疾病，由细菌病原体百日咳杆菌急性感染引起。在美国，尽管疫苗被广泛使用，但2012年报告的病例数量达到了60年来的最高水平，许多其他病例没有报告。几个州经历了50多年来最严重的百日咳疫情，多名婴儿死亡，数千例病例。患有百日咳的人通常会经历持续数周的衰弱咳嗽发作，但没有有效的治疗方法。百日咳感染呼吸道并产生大量毒素，对宿主产生不利影响并调节宿主反应。其中百日咳毒素(PT)是百日咳杆菌特有的一种重要毒力因子。PT-ADP-核糖基化哺乳动物细胞中的异源三聚体Gi蛋白，扰乱G蛋白偶联受体(GPCR)信号通路，对细胞产生广泛的下游效应。我们假设PT通过对宿主的多方面影响而导致百日咳感染和疾病。我们先前发现PT对宿主免疫反应有几种抑制作用，包括抑制有利于细菌感染的先天免疫反应。然而，我们的初步数据表明，PT在百日咳杆菌感染的高峰期刺激多种呼吸道炎症反应，包括一种被称为垂蛋白的上皮性阴离子转运体的表达增加。垂丝蛋白调节呼吸道表面液体体积和黏液粘度，并与哮喘和COPD小鼠模型的呼吸道病理有关，因此是百日咳呼吸道病理的潜在贡献者。我们也有初步数据表明，PT可增加炎症介质缓激肽的呼吸水平，缓激肽与包括咳嗽在内的几种呼吸道病理有关，并且PT可加重对缓激肽的呼吸反应。因此，我们假设PT通过多种作用参与百日咳呼吸道病理，包括上调促成呼吸道病理的因子(如支链蛋白)和加重对炎症介质(如缓激肽)的呼吸反应。使用百日咳杆菌感染的小鼠模型和体外互补方法，我们将在两个特定的目标上检验这些假说，以确定这些PT介导的效应在百日咳呼吸道病理中的作用。本项目的总体目标是了解PT在百日咳呼吸器病理中的作用(S)，以期确定治疗和预防百日咳的新疗法的可能靶点。

DESCRIPTION (provided by applicant): Pertussis (whooping cough) is a respiratory disease of humans caused by acute infection with the bacterial pathogen Bordetella pertussis. In the U.S., despite widespread vaccine use, the number of reported cases in 2012 was at a 60-year high, and many other cases go unreported. Several states experienced their worst pertussis epidemic in over 50 years, with multiple infant deaths and thousands of cases. Individuals suffering from pertussis typically experience debilitating cough episodes that last for weeks, but there is no effective treatment for this disease. B. pertussis infects the respiratory tract and produces a number of toxins that adversely affect the host and modulate host responses. One of these toxins, pertussis toxin (PT), is an important virulence factor uniquely produced by B. pertussis. PT ADP-ribosylates heterotrimeric Gi proteins in mammalian cells, disrupting G protein-coupled receptor (GPCR) signaling pathways and causing a wide range of downstream effects on the cell. We hypothesized that PT contributes to pertussis infection and disease through multiple effects on the host. We previously found that PT has several inhibitory effects on the host immune response, including inhibition of innate immune responses that favor bacterial infection. However, our preliminary data here demonstrate that PT stimulates multiple airway inflammatory responses at the peak of B. pertussis infection, including increased expression of an epithelial anion transporter known as pendrin. Pendrin regulates airway surface liquid volume and mucus viscosity, and is implicated in airway pathology in mouse models of asthma and COPD, and therefore represents a potential contributor to pertussis respiratory pathology. We also have preliminary data that PT increases respiratory levels of the inflammatory mediator bradykinin, a peptide implicated in several airway pathologies including cough, and that PT exacerbates respiratory responses to bradykinin. Therefore, we hypothesize that PT is involved in pertussis airway pathology through multiple effects, including upregulation of factors that contribute to airway pathology (such as pendrin) and exacerbation of respiratory responses to inflammatory mediators (such as bradykinin). Using mouse models of B. pertussis infection combined with complementary in vitro approaches, we will test these hypotheses in two specific aims to determine the roles of these PT-mediated effects in pertussis airway pathology. The broad objective of this project is to understand the role(s) of PT in the respirator pathology of pertussis disease, with a view to identification of possible targets for novel therapeutics to treat and prevent pertussis.