Early Life Rhinovirus Infection and Childhood Asthma

项目摘要 出生队列研究发现，生命早期喘息相关的呼吸道疾病 呼吸道感染和13岁以下儿童哮喘的发展。这些研究表明 早期呼吸道感染对肺和/或免疫细胞发育有直接影响， 哮喘为了确定可能的机制，我们建立了早期RV感染的小鼠模型。感染 的6日龄小鼠，而不是成熟小鼠，诱导持久的粘液化生，嗜酸性粒细胞炎症和 气道高反应性（AHR），其与2型先天性淋巴样细胞（ILC2）扩增相关， 依赖于IL-13、IL-25和IL-33。对于这次续约申请，我们已经制定了初步数据， 表明早期RV感染增加了气道IL-25 + DCLK1+刷状细胞的数量， 持续ILC2依赖性哮喘样表型的机制。此外，我们还发现，在 未成熟小鼠，NLRP 3炎性体的激活和IL-1 β成熟抑制2型细胞因子 表达和粘膜化生。在本建议中，我们将测试一般假设，在早期- 终生RV感染、发生ILC 2依赖性2型气道炎症和粘液化生 代表簇状细胞RV诱导的IL-25信号传导（促进表型）和NLRP 3- 依赖性IL-1 β信号传导（抑制表型）。为了验证这一点，我们提出以下目标： 具体目标1。确定气道刷状（簇状）细胞对病毒诱导的IL-25的贡献 生产我们假设：1）早期RV感染刺激了RV数量的持续增加， 产生IL-25的气道簇细胞; 2）RV诱导的ILC2扩增、粘液化生和炎症反应需要簇细胞; 3）RV诱导的IL-25和IL-13的产生（通过ILC2和M2极化的巨噬细胞）构成了一种新的免疫调节机制。 簇细胞发育的前馈机制。 具体目标2。确定IL-1 β在RV诱导的粘膜化生发展中的作用 和AHR。我们假设：1）在未成熟小鼠中，RV诱导的NLRP 3炎性体依赖性IL-1 β 2）IL-1 β抑制上皮细胞天然细胞因子的表达; 和3）LPS和与狗相关的屋尘各自减弱粘液化生表型的发展 通过刺激炎性小体引发和激活。 具体目标3。确定早期RV-C感染的影响。我们假设：1）比较 与RV-A相比，RV-C感染6日龄小鼠可诱导更多的2型炎症、粘膜化生和AHR; 2） RV-C诱导簇状细胞的更大扩增; 3）RV-C促进炎性体引发但不激活，从而 允许更大和更持久的2型细胞因子表达和粘膜化生。 将研究患有呼吸道病毒感染的未成熟小鼠和婴儿。完成拟议工作 将为哮喘的发病机制提供新的见解，并确定新的预防目标。

Project Summary Birth cohort studies have found significant associations between early-life wheezing-associated respiratory tract infections and the development of asthma in children up to 13 years of age. These studies suggest that early life respiratory tract infections have a direct effect on lung and/or immune cell development and the risk of asthma. To determine possible mechanisms, we established a mouse model of early-life RV infection. Infection of 6 day-old mice, but not mature mice, induces long-lasting mucous metaplasia, eosinophilic inflammation and airways hyperresponsiveness (AHR) which is associated with type 2 innate lymphoid cell (ILC2) expansion and dependent on IL-13, IL-25 and IL-33. For this renewal application, we have developed preliminary data showing that early-life RV infection increases the number of airway IL-25+ DCLK1+ brush cells, providing a mechanism for a persistent ILC2-dependent asthma-like phenotype. In addition, we have found that, in immature mice, activation of the NLRP3 inflammasome and IL-1β maturation inhibits type 2 cytokine expression and mucous metaplasia. In this proposal, we will test the general hypothesis that, following early- life RV infection, development of ILC2-dependent type 2 airway inflammation and mucous metaplasia represents a balance between tuft cell RV-induced IL-25 signaling (promotes the phenotype) and NLRP3- dependent IL-1β signaling (suppresses the phenotype). To test this, we propose the following Aims: Specific Aim 1. Determine the contribution of airway brush (tuft) cells to viral-induced IL-25 production. We hypothesize that: 1) early-life RV infection stimulates a persistent increase in the number of IL-25-producing airway tuft cells; 2) tuft cells are required for RV-induced ILC2 expansion, mucous metaplasia and AHR; 3) RV-induced IL-25 and IL-13 production (by ILC2s and M2 polarized macrophages) constitute a feed-forward mechanism for tuft cell development. Specific Aim 2. Determine the role of IL-1β on the development of RV-induced mucous metaplasia and AHR. We hypothesize that: 1) in immature mice, RV-induced, NLRP3 inflammasome-dependent IL-1β production suppresses the asthma-like phenotype; 2) IL-1β inhibits epithelial cell innate cytokine expression; and 3) LPS and dog-associated house dust each attenuate development of the mucous metaplasia phenotype by stimulating inflammasome priming and activation. Specific Aim 3. Determine the effects of early-life RV-C infection. We hypothesize that: 1) compared to RV-A, RV-C infection of 6 day-old mice induces more type 2 inflammation, mucous metaplasia and AHR; 2) RV-C induces greater expansion of tuft cells; 3) RV-C elicits inflammasome priming but not activation, thereby permitting greater and more long-lasting type 2 cytokine expression and mucous metaplasia. Immature mice and infants with respiratory viral infections will be studied. Completion of the proposed work will provide new insight into the pathogenesis of asthma development, and identify new targets for prevention.