Preterm birth, lung innate immunity, and RSV

描述（由申请方提供）：呼吸道合胞病毒（RSV）感染是导致儿童住院的呼吸道疾病的最常见原因。早产儿特别容易受到严重的RSV感染。呼吸道上皮是RSV感染的起始部位，上皮细胞沿着肺泡巨噬细胞（AM）和树突状细胞（DC）对于先天性和适应性免疫应答至关重要。然而，早产儿中上皮细胞和AM-DC的先天免疫基因表达的程度可能是可变的/有限的。假设是：呼吸道上皮细胞和AM-DC早产儿先天免疫力降低增强了对RSV感染的易感性。该假设基于上述事实和我们在羔羊中的初步数据，表明早产儿表面活性蛋白A和D（SP-AD）、绵羊β-防御素-1（SBD-1）和Toll样受体4（TLR 4）的表达有限。将在与人类疾病（包括易感性、病变和先天免疫）密切相似的早产羔羊中进行试验。特异性目的1比较了关键先天免疫基因（SBD-1、SP-AD、TLR 4）的表达和体内蛋白质/肽的产生，以及早产和足月肺中AM-DC细胞因子的表达。本发明还检验了以下假设：有限的上皮细胞增殖和/或分化早产是有限的SP-AD、SDB-1表达的机制基础，并通过比较有或没有细胞增殖和分化的早产和足月培养细胞中的转录活性、蛋白质/肽产生来检验这一点。特定目标2测试了以下假设：在羔羊模型和体外培养的上皮细胞中，SP-AD、SBD-1和AM-DC对RSV的反应在足月前比足月时要小。第二个假设，即上皮细胞的细胞增殖和/或分化增加可防止RSV感染，将在体外用目标1的治疗进行测试。SP-AD、SBD-1直接预防RSV感染的程度将用RNAi测定法进行测试。特异性目的3检验了以下假设：与细胞增殖/分化一起表达的其他先天免疫基因可预防RSV感染。该目的使用原代极化人肺细胞的基因表达谱和呼吸道上皮特异性探针集（Unigene），该探针集是迄今为止注释最好和定义最明确的基因靶点集。它还鉴定了人类基因的绵羊直系同源物，并检测了早产儿表达受损/降低。该团队结合了兽医和人类医学专业知识，以实现该项目的目标：发现SP-AD，SBD-1和其他先天免疫基因表达不足的原因，以及早产时易患RSV感染的AMDC反应。这项工作是重要的，因为它发现了RSV易感性的基础，早产和机制的方法，以提高先天免疫。

DESCRIPTION (provided by the applicant): Respiratory syncytial virus (RSV) infection is the most common cause of respiratory disease leading to hospitalization in children. Preterm infants are especially susceptible to severe RSV infection. Respiratory epithelium is an initial site of RSV infection and epithelial cells along with alveolar macrophages (AM) and dendritic cells (DC) are vital to innate and adaptive immune responses. However, the extent of innate immune gene expression by epithelia and AM-DC in preterm infants can be variable/limited. The hypothesis is that: Reduced innate immunity by respiratory epithelia and AM-DC preterm enhances susceptibility to RSV infection This hypothesis is based on the facts above and our preliminary data in lambs demonstrating limited expression of surfactant proteins A and D (SP-AD), sheep beta-defensin-1 (SBD-1), and Toll-like receptor 4 (TLR4) preterm. It will be tested in preterm lambs which have close similarities with human disease including susceptibility, lesions, and innate immunity. Specific Aim 1 compares expression of key innate immune genes (SBD-1, SP-AD, TLR4) and protein/peptide production in vivo as well as AM-DC cytokine expression in pre- and full-term lung. It also tests the hypothesis that limited epithelial cell proliferation and/or differentiation pre-term underlie(s) the mechanistic basis for limited SP-AD, SDB-1 expression and tests this by comparing transcriptional activity, protein/peptide production in pre- and full term cultured cells with or without cell proliferation and differentiation. Specific Aim 2 tests the hypothesis that SP-AD, SBD-1 and AM-DC responses to RSV are less at pre- than full-term in the lamb model and in vitro with cultured epithelial cells. A second hypothesis, that increased cell proliferation and/or differentiation of epithelia protects against RSV infection, will be tested in vitro with treatments from Aim 1. The extent to which SP-AD, SBD-1 directly prevent RSV infection will be tested with RNAi assays. Specific Aim 3 tests the hypothesis that yet other innate immune genes expressed with cell proliferation/differentiation prevent RSV infection. This Aim uses gene expression profiling of primary polarized human lung cells and a respiratory epithelia-specific probe set (Unigene) that is the most well-annotated and defined gene target set to date. It also identifies ovine orthologs of human genes and test for impaired/reduced expression preterm. This team combines veterinary and human medical expertise to attain the goal of this project: to discover the reason(s) for inadequate expression of SP-AD, SBD-1 and other innate immune genes as well as AMDC responses at preterm that predispose to RSV infection. The work is significant because it discovers the underlying basis for RSV susceptibility preterm and mechanistic approaches to enhance innate immunity.