Lung Structural and Functional Alterations Following Early-life RSV Infection

摘要 严重的呼吸道合胞病毒（RSV）感染与儿童的发育有关 哮喘在这项提议中，我们的假设将测试早期病毒感染是否会导致肺部发育， 以及重塑改变，这些改变对以后的生活中的肺功能产生负面影响。我们的初步数据显示 早期RSV感染改变了肺发育，导致ECM紊乱和肺泡上皮细胞简化， 间隙，导致肺功能测试（PFT）显示肺功能下降。新生儿RSV后5周 感染时，在测量的PFT参数中观察到与肺功能降低一致的显著缺陷。 早期生命的肺有一个特别修改的免疫环境，以适当的肺发育发生 这种易感性可能会通过劫持这些病毒来增强呼吸道病毒感染的有害影响， 导致肺部发育不良的项目。ILC 2在正常肺发育早期具有已知的作用， 并提供IL-13用于适当的肺泡化。在此期间，ECM正在组织，特别是弹性蛋白 和胶原沉积，以及正常肺发育所需的肺泡化。无论多么不合适 和/或这些程序的过度激活与严重的肺功能障碍有关。ILC 2以及树突状细胞 (DC)与IL-33和TSLP一起参与有害的肺重塑沿着， RSV感染后。我们实验室以前的研究表明，“炎性”DC和ILC 2是 在早期RSV感染后小鼠肺中持续增加，我们的初步数据显示， 它们与以后生活中改变的肺发育和功能障碍相关。免疫荧光成像5 感染后10周显示弹性蛋白沉积增加，与对照组相比， 同年龄的幼稚动物。我们还观察到IL 33和TSLP在离体气道中的表达增加， 来自感染后5周小鼠的上皮细胞，表明与感染相关的肺结构细胞的明显变化。 积累的先天性免疫细胞，DC和ILC 2。5周龄新生儿呼吸道合胞病毒DC的转移 感染的小鼠进入新生的幼稚小鼠导致肺功能下降，沿着增加的IL 13和弹性蛋白 在转移后5周在肺中的表达。后一项研究将改变的DC与早期RSV感染联系起来 与发育异常有关的肺部病理学我们假设早期RSV感染 促进TSLP驱动的DC修饰，改变ILC 2活性，导致肺功能失调 发育、持续性致病性结构改变和肺功能下降。我们的研究将 测试和确定在导致ILC 2活性改变的早期RSV感染后训练的DC免疫的作用 在肺结构发育过程中。我们将靶向已知影响DC和ILC 2细胞因子的TSLP途径 生产，导致强烈的免疫病理反应。这些研究将确定生命早期的呼吸系统 病毒感染导致肺部发育发生病因性改变，并具有与激活相关的明确机制 关键的先天性免疫细胞，长期后遗症，使婴儿在以后的生活中改变肺功能。

Abstract Severe respiratory syncytial virus (RSV) infection has been associated with the development of childhood asthma. In this proposal, our hypothesis will test whether early-life viral infections lead to lung developmental and remodeling alterations that negatively impact lung function later in life. Our preliminary data demonstrate that early-life RSV infection modifies lung development leading to disorganized ECM and simplified alveolar spaces, that lead to decreased lung function by pulmonary function tests (PFT). At 5 weeks post-neonatal RSV infection, significant defects are observed in measured PFT parameters consistent with decreased lung function. The early-life lung has a specifically modified immune environment in order for proper lung development to occur and this predisposition may enhance the detrimental effects of respiratory viral infection by hijacking these programs leading to improper lung development. ILC2 have a known role for normal lung development early in life and provide IL-13 for proper alveolarization. During this period, the ECM is being organized, especially elastin and collagen deposition, as well as alveolarization needed for normal lung development. However inappropriate and/or overactivation of these programs have been linked to severe lung dysfunction. ILC2 as well dendritic cells (DC), have been implicated in detrimental lung remodeling along with IL-33 and TSLP which are upregulated following RSV infection. Previous studies from our lab have shown that “inflammatory” DC and ILC2 are persistently increased in the lungs of mice following early-life RSV infection and our preliminary data show that they correlate to the altered lung development and dysfunction later in life. Immunofluorescent imaging at 5 weeks post-infection showed increased elastin deposition and the appearance of disorganized ECM compared to naïve animals of the same age. We also observed increased expression of Il33 and Tslp in isolated airway epithelial cells from 5 week post-infection mice, demonstrating clear changes in lung structural cells that link to the accumulated innate immune cells, DC and ILC2. The transfer of DC isolated from 5 week post-neonatal RSV infected mice into neonatal naïve mice led to decreased lung function along with increased Il13 and elastin expression in the lungs at 5 weeks post-transfer. These latter studies link altered DC from early-life RSV infection to lung pathology associated with altered development. We hypothesize that early-life RSV infection promotes TSLP-driven DC modifications that alter ILC2 activity leading to dysregulated lung development, persistant pathogenic structural alterations and decreased lung function. Our studies will test and define the role of trained DC immunity after early-life RSV infection that leads to altered ILC2 activity during lung structural development. We will target the TSLP pathway that is known to affect DC and ILC2 cytokine production, leading to strong immunopathogenic responses. These studies will define how early-life respiratory viral infection leads to causative alterations in lung development with defined mechanisms linking activation of critical innate immune cells to long term sequelae predisposing infants to altered lung function later in life.