Clock Gene Control of Viral Infection and Asthma

项目摘要 哮喘是一种常见的肺部疾病，其活动受到时间的强烈影响。哮喘的症状各不相同 季节（反映呼吸道病毒感染率），它们也随一天中的时间而变化，因此许多 病人在半夜会出现最严重的症状。后者表明生物钟， 一组基因产生昼夜节律，与哮喘有关。虽然病毒和昼夜节律 节奏都是已知的影响哮喘症状，这两个方面的疾病从来没有 机械连接。在这里，我们发现一种叫做bmal 1的生物钟基因可能通过以下方式影响哮喘： 调节肺部对常见呼吸道病毒的反应。我们发现生物钟基因bmal 1的破坏 在小鼠中产生对副流感病毒和甲型流感病毒的异常抗病毒反应，导致严重的 下呼吸道感染bmal 1的抗病毒作用似乎局限于气道上皮细胞， 该基因在急性病毒性疾病期间协调干扰素应答。急性感染消退后，我们显示 在小鼠中，BMAL 1缺乏会加重病毒感染后慢性气道疾病，包括 哮喘肺部的特征。最后，我们发现bmal 1在气道样本中表达下调， 哮喘病人的。基于这些数据，我们假设生物钟调节抗病毒药物， 气道上皮细胞通过bmal 1的反应，从而控制急性和慢性病毒性肺炎的严重程度。 肺病理学我们进一步假设，昼夜节律钟功能是有缺陷的气道上皮细胞， 哮喘患者，导致bmal 1表达减少，并可能解释了 这些病人都感染了呼吸道病毒。确定bmal 1介导抗病毒的机制， 我们提出以下具体目的：1）确定bmal 1在气道中的 上皮细胞控制干扰素基因表达和急性呼吸道病毒性疾病的严重程度 2）确定bmal 1缺陷如何促进小鼠中的病毒后慢性气道疾病;以及，3） 确定哮喘患者气道上皮生物钟功能障碍的性质 患者我们将通过使用气道条件性bmal 1基因敲除小鼠和体外培养bmal 1基因来研究Aim 1。 无效小鼠气管上皮细胞，以描绘该基因如何调节干扰素对呼吸道感染的反应。 病毒（仙台和甲型流感病毒）。我们将通过使用他莫昔芬诱导的bmal 1敲除来解决Aim 2 小鼠以确定在感染过程中何时需要bmal 1来调节病毒后肺病。我们 将通过使用荧光素酶报告系统分析生物钟功能和bmal 1表达来解决Aim 3 在培养的人气道细胞中，来自正常和哮喘受试者。

PROJECT SUMMARY Asthma is a common lung disorder whose activity is strongly influenced by time. Asthma symptoms vary with the season (reflecting rates of respiratory viral infection), and they also vary by the time of day, such that many patients experience their worst symptoms in the middle of the night. The latter suggests that the circadian clock, a collection of genes that produce circadian rhythms, is connected to asthma. While viruses and circadian rhythms are both known to affect asthma symptoms, these two aspects of disease have never been mechanistically linked. Here, we discovered that a circadian clock gene called bmal1 may impact asthma by regulating the lung’s response to common respiratory viruses. We show that disruption of the clock gene bmal1 in mice produces an aberrant antiviral response to parainfluenza and influenza A viruses, resulting in severe lower respiratory tract infection. The antiviral actions of bmal1 appear localized to airway epithelial cells, where this gene orchestrates interferon responses during acute viral illness. After the acute infection resolves, we show in mice that bmal1 deficiency exacerbates post-viral chronic airway disease, including features that are characteristic of asthmatic lungs. Finally, we found that bmal1 expression is down-regulated in airway samples from asthma patients. Based on these data, we hypothesize that the circadian clock regulates the antiviral responses of airway epithelial cells through bmal1, and thereby controls the severity of acute and chronic viral lung pathology. We further hypothesize that circadian clock function is defective in the airway epithelial cells of asthmatics, leading to reduced bmal1 expression, and potentially explaining the heightened susceptibility that these patients have to respiratory viruses. To determine the mechanism by which bmal1 mediates antiviral defenses in the respiratory system we propose the following Specific Aims: 1) Determine how bmal1 in airway epithelial cells controls interferon gene expression and the severity of acute respiratory viral illness in mice; 2) Determine how bmal1 deficiency promotes post-viral chronic airway disease in mice; and, 3) Determine the nature of the circadian clock dysfunction in the airway epithelium of asthmatic patients. We will address Aim1 by using airway-conditional bmal1 knockout mice and in vitro culture of bmal1- null mouse tracheal epithelial cells to delineate how this gene regulates the interferon response to respiratory viruses (Sendai and Influenza A viruses). We will address Aim 2 by using tamoxifen-inducible bmal1 knockout mice to define when in the course of infection bmal1 is needed for the regulation of post-viral lung disease. We will address Aim 3 by using a luciferase reporter system to analyze circadian clock function and bmal1 expression in cultured human airway cells, derived from normal and asthmatic subjects.