Viral and Host Determinants of Infant and Childhood Allergy and Asthma

这项应用的长期目标是确定婴儿呼吸道合胞病毒与 (RSV)感染和使哮喘发生的宿主反应，发展RSV和 哮喘预防策略。有大量证据表明，在儿童时期经历严重呼吸道合胞病毒的儿童 婴儿期在童年后期患哮喘的风险更大；然而，宿主和病毒决定因素 导致哮喘发生的原因尚不清楚。在我们之前的融资周期中，我们进行了一项研究，考虑到 婴儿期呼吸道合胞病毒感染作为一种自然的准随机事件，表明婴幼儿呼吸道合胞病毒感染不仅 严重感染与哮喘风险增加有关，在婴儿期未发现RSV感染 预防哮喘的发生。此外，我们还证实了婴儿呼吸道合胞病毒感染的中介作用。 关于发育中的呼吸道微生物群和免疫发展以及喘息的风险，在初步数据中， 呼吸道合胞病毒对呼吸道上皮细胞长期代谢的影响我们对这一提议的总体假设 婴儿呼吸道合胞病毒感染的年龄依赖性效应是否通过改变 呼吸道上皮DNA甲基化(DNaM)与呼吸道上皮代谢和发育 编程，识别基因x RSV相互作用将解释哮喘易感性的极端 在婴儿感染呼吸道合胞病毒后。该提案利用丰富的数据集和出生队列来解决这些问题 假说，并有可能极大地促进对机制和发展的理解 呼吸道合胞病毒对反复喘息和哮喘影响的潜在过程。为了检验这些假设，我们将使用 两项专门设计的婴儿呼吸道合胞病毒感染的自然准随机研究 探讨婴幼儿呼吸道合胞病毒感染对呼吸道健康和呼吸道上皮细胞的影响。 呼吸道合胞病毒感染鼻呼吸道上皮细胞的模型以及前沿实验室和 整合复杂数据的分析方法。项目2利用来自INSPIRE队列的数据 这表明，出生时L-瓜氨酸(L-CIT)婴儿血液水平的升高与 降低婴儿患毛细支气管炎的几率。这些数据表明，出生时L-CIT的血液水平较高 防止婴儿毛细支气管炎，并可能防止儿童后期哮喘的发展。 我们假设，与普通日粮(RD)相比，父母喂养的L-CIT添加日粮(L-CITSD) 在怀孕期间和他们的后代预防严重的呼吸道合胞病毒毛细支气管炎。我们的初步数据 有力地支持了这一假说，并揭示了L合剂可降低呼吸道合胞病毒诱导的肺IL-13的表达。 降低肺组织IL-13表达ILC2的频率，抑制气道反应性。此外，L-- 当IL-33体外刺激细胞时，CITSD显著降低IL-13的ILC2表达，并 在ILC2培养中加入L-CIT可抑制IL-33诱导的IL-13的产生。这些研究支持了L是一位 治疗目标是降低严重呼吸道合胞病毒毛细支气管炎和随后的儿童哮喘的风险。

The long-term objective of this application is to define the relationship between infant respiratory syncytial virus (RSV) infection and the host response that enables asthma inception, data needed to develop RSV and asthma prevention strategies. There is abundant evidence that children who experience severe RSV during infancy are at greater risk for developing asthma later in childhood; however, the host and viral determinants that lead to asthma development are not known. In our prior funding cycle, we conducted a study considering RSV infection in infancy as a natural quasi-random event and demonstrated that infant RSV infection, not only severe infection, is associated with increased asthma risk, and that missing RSV infection during infancy protects from asthma development. Furthermore, we demonstrated the mediating effect of infant RSV infection on the developing airway microbiome and immune development and risk of wheeze, and in preliminary data, the effect of RSV on long-term airway epithelial cell metabolism. Our overarching hypothesis for this proposal is that age-dependent effects of infant RSV infection contribute to chronic respiratory disease through altering DNA methylation (DNAm) of the airway epithelium, and airway epithelial metabolism and developmental programming, and that identifying gene x RSV interactions will explain extremes of asthma susceptibility following infant RSV infection. This proposal leverages rich data sets and birth cohorts to address these hypotheses, and has the potential to greatly advance understanding of the mechanisms and developmental processes underlying the effect of RSV on recurrent wheeze and asthma. To test these hypotheses we will use a combination of two human natural quasi-randomization studies of infant RSV infection specifically designed to assess effects of infant RSV infection on subsequent respiratory health and the airway epithelium, in vitro models of RSV infection of nasal airway epithelial cells (NAECs), along with cutting edge-laboratory and analytic approaches to integrate the resultant complex data. Project 2 leverages data from the INSPIRE cohort that revealed that increased infant blood levels at birth of L-citrulline (L-CIT) were significantly associated with decreased odds of infant bronchiolitis. These data suggested that higher blood levels of L-CIT at time of birth protected against infant bronchiolitis and may protect against the development of asthma later in childhood. We hypothesize that compared to regular diet (RD), an L-CIT supplemented diet (L-CITsd) fed to parents during gestation and their offspring prevents severe RSV bronchiolitis in the offspring. Our preliminary data strongly support this hypothesis and reveal that the L-CITsd decreased RSV-induced lung IL-13 expression, reduced the frequency of lung IL-13 expressing ILC2, and restrained airways responsiveness. Further, L- CITsd significantly decreased ILC2 expression of IL-13 when the cells were stimulated ex vivo with IL-33, and L-CIT added to ILC2 culture inhibited IL-33-induced IL-13 production. These studies support that L-CITsd is a therapeutic target to decrease the risk for severe RSV bronchiolitis and subsequent childhood asthma.