Preterm birth, lung innate immunity, and RSV

描述(申请人提供)：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呼吸道合胞病毒感染。呼吸道上皮细胞是呼吸道合胞病毒感染的起始部位，呼吸道上皮细胞与肺泡巨噬细胞(AM)和树突状细胞(DC)一起对先天性和获得性免疫反应至关重要。然而，早产儿上皮细胞和AM-DC先天免疫基因表达的程度可能是可变的/有限的。这一假说是：呼吸道上皮细胞和AM-DC早产儿的先天免疫功能降低提高了对RSV感染的易感性。这一假说是基于上述事实和我们在羔羊中的初步数据显示表面活性蛋白A和D(SP-AD)、绵羊β-防御素-1(SBD-1)和Toll样受体4(TLR4)的表达有限。它将在早产羔羊身上进行测试，这些羔羊与人类疾病有密切的相似之处，包括易感性、病变和先天免疫。特定目的1比较先天免疫关键基因(SBD-1、SP-AD、TLR4)的表达、体内蛋白质/多肽的产生以及AM-DC细胞因子在早产和足月肺中的表达。它还验证了早产(S)限制上皮细胞增殖和/或分化是SP-AD、SDB-1表达受限的机制基础的假说，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的转录活性、蛋白质/肽产生来检验这一假说。在绵羊模型和体外培养的上皮细胞中，特定目的2验证了SP-AD、SBD-1和AM-DC对RSV的反应在足月前低于足月的假设。第二个假设是，增加细胞增殖和/或上皮细胞分化可以防止RSV感染，这一假说将在体外通过目标1的治疗进行测试。SP-AD、SBD-1直接预防RSV感染的程度将通过RNAi分析进行测试。特殊目的3验证了这样一种假设，即还有其他与细胞增殖/分化有关的先天免疫基因可以防止RSV感染。这一目标使用了原代极化的人肺细胞的基因表达谱和呼吸道上皮细胞特异性探针集(Unigene)，这是迄今为止注释最充分和定义最明确的基因靶集。它还识别绵羊的人类基因同源基因，并测试早产/表达受损/减少。这个团队结合了兽医和人类的医学专业知识来实现这个项目的目标：发现SP-AD、Sbd-1和其他先天免疫基因表达不足的原因(S)，以及早产儿易患呼吸道合胞病毒感染的AMDC反应。这项工作意义重大，因为它发现了RSV易感性、早产和增强先天免疫的机械性方法的潜在基础。

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.