Rhinovirus and Airway Epithelial Cell Responses

描述（由申请人提供）：病毒感染，最常见的是人鼻病毒（HRV），是哮喘发作的最常见原因。理论上，由hrv感染的上皮细胞产生的趋化因子诱导炎症细胞向气道募集，这反过来又产生了能够增加气道反应的细胞因子和介质。然而，这种模式不能解释为什么哮喘患者在感冒后会出现下呼吸道疾病的表现，而正常人却没有。这一提议验证了一个新的假设，即预先存在的气道疾病，无论是过敏性还是非过敏性，都会改变气道巨噬细胞的极化状态，导致对鼻病毒感染的反应改变。与此一致，我们的试验数据表明，过敏原致敏和卵清蛋白（OVA）的攻击改变了对HRV感染的反应，从嗜中性粒细胞反应转变为th2主导的嗜中性粒细胞和嗜酸性粒细胞联合反应，部分由巨噬细胞产生eotaxin-1/CCL11和MCP-1/CCL2介导。hrv感染的巨噬细胞在体内和体外产生eotaxin-1和MCP-1，巨噬细胞耗竭可减轻hrv增强的气道嗜酸性粒细胞炎症和高反应性。最后，ova处理小鼠的巨噬细胞显示出Arg-1、m-1和MGL-2的表达增加。气道对HRV感染的整体反应不仅取决于促炎途径，还取决于抗病毒反应。据推测，由于干扰素（IFN）产生不足，哮喘患者容易发生hrv诱导的恶化。然而，IFN产生的减少可能伴随着炎症反应的减弱，这将倾向于防止哮喘恶化。事实上，我们的试验数据显示，感染hrv1b的toll样受体-3 -/-小鼠具有较低的IFN反应，气道炎症和反应性降低。在本研究中，我们将研究体内hrv诱导IFN表达所需的信号中间体，并测试IFN产生受损是否会导致hrv诱导的气道炎症增加。我们提出以下具体目标：确定既往气道疾病对HRV反应的影响。具体目标2。确定巨噬细胞在hrv诱导的小鼠气道疾病恶化中的作用。具体目标3。测定体内干扰素产生受损对病毒载量和气道炎症的影响。这项包括动物和人类研究的工作的完成，将为尚不清楚的病毒引起的哮喘发作提供一个新的范例，确定治疗干预的分子靶点，引入一种检测呼吸道病毒的设备，并直接验证IFN产生受损导致更严重哮喘恶化的假设。

DESCRIPTION (provided by applicant): Viral infections, most commonly by human rhinovirus (HRV), are the most frequent cause of asthma attacks. In theory, chemokine production by HRV-infected epithelial cells induces the recruitment of inflammatory cells to the airways, which in turn elaborate cytokines and mediators capable of increasing airway responses. This paradigm, however, fails to explain why asthmatics experience manifestations of lower airways disease following colds while normals do not. This proposal tests the novel hypothesis that pre-existing airways disease, either allergic or non-allergic, modifies the polarization state of airway macrophages, leading to an altered response to rhinovirus infection. Consistent with this, our pilot data indicate that allergen sensitization and challenge with ovalbumin (OVA) alters the response to HRV infection from a neutrophilic response to a Th2-dominant, combined neutrophilic and eosinophilic response that is mediated in part by macrophage production of eotaxin-1/CCL11 and MCP-1/CCL2. HRV-infected macrophages produce eotaxin-1 and MCP-1 in vivo and ex vivo, and macrophage depletion attenuates HRV-enhanced airway eosinophilic inflammation and hyperresponsiveness. Finally, macrophages from OVA-treated mice show increased expression of the alternative activation markers Arg-1, Ym-1 and MGL-2. The overall airway response to HRV infection depends not only on pro-inflammatory pathways but also the antiviral response. It has been hypothesized that asthmatics are prone to HRV-induced exacerbations due to deficient interferon (IFN) production. However, reduced IFN production may be accompanied by attenuated inflammatory responses, which would tend to protect against asthma exacerbation. Indeed, our pilot data show that HRV1B-infected Toll-like receptor-3 -/- mice with lower IFN responses show reduced airways inflammation and responsiveness. In this application, we will examine the signaling intermediates required for HRV-induced IFN expression in vivo, and test whether impaired IFN production leads to increased HRV-induced airway inflammation. We propose the following Specific Aims: Specific Aim 1. Determine the effects of preexisting airways disease on HRV responses. Specific Aim 2. Determine the role of the macrophage in HRV-induced exacerbations of pre- existing airways disease in mice. Specific Aim 3. Determine the effect of impaired IFN production on viral load and airway inflammation in vivo. Completion of this work, which includes both animal and human studies, will provide a new paradigm for poorly-understood viral-induced asthma attacks, identify molecular targets for therapeutic intervention, introduce a device for detection of respiratory viruses, and directly test the hypothesis that impaired IFN production leads to more severe asthma exacerbations. PUBLIC HEALTH RELEVANCE: Viral infections, most commonly caused by rhinovirus, are the most frequent cause of asthma attacks. This application seeks to understand the cellular and biochemical mechanisms underlying rhinovirus-induced asthma exacerbations. It proposes a new paradigm in which rhinovirus infects alternatively polarized macrophages, resulting in exaggerated pro-inflammatory responses. Insight provided from the proposed studies may lead to new treatments for asthma and other chronic airways diseases.