Mechanisms of age-specific differences in the Type I IFN response to respiratory viral infection

项目摘要/摘要 呼吸道病毒感染在很大程度上造成了全球婴儿的损失，并对早产造成了不成比例的影响 新生儿。在所有不到12个月大的婴儿继发于呼吸道病毒感染的死亡中，55%发生在 妊娠30周前出生的新生儿。直到最近，大多数关于新生儿和婴儿的研究都是初级的 对病毒感染的免疫反应是基于概括到新生儿的成年动物模型的数据。 目前的数据表明，与人类婴儿更相关的模型是新生小鼠，因为 出生后免疫系统的类似进化。我们已经建立了一个3日龄小鼠的幼鼠模型 流感病毒感染，相当于早产晚期(34-37周)的人类新生儿。要确定 我们用纳米串技术测量了流感病毒初始先天反应的年龄差异 新生儿和成人全肺12h诱导的753个免疫相关基因的RNA转录变化 感染PR8流感病毒后与未感染的年龄匹配的新生儿。感染后12小时， 新生的小鼠与未感染的年龄匹配的小鼠有相似的转录图谱，而 感染的成年小鼠上调了数百个基因，特别是在I型干扰素(干扰素)途径中， 抗病毒防御的基本组成部分。尽管I型干扰素诱导关键的抗病毒途径，但干扰素也可以 用来放大促炎反应，这会增加成人呼吸道的损害。 然而，婴儿特异性I型干扰素的动力学以及I型干扰素对婴儿是保护还是有害 代表着巨大的知识鸿沟。在初步研究中，缺乏I型干扰素受体的新生小鼠 (干扰素αβR-/-)在感染流感病毒后存活率大大提高，与 C57BL/6的存活率仅为15%。这与成年老鼠的情况正好相反，成年老鼠的病毒感染率更高。 在缺乏I型干扰素反应的情况下致病。我们假设新生儿患有异常的I型 干扰素对流感病毒的反应动力学直接导致氧化应激、炎症和肺组织 损坏。由于干扰素αβ受体的存在对成人具有保护作用，我们还假设 新生儿干扰素αβ受体依赖性反应可能涉及与成人I型不同的下游通路 干扰素应答。为了验证这一假设，我们建议调查婴儿的发育差异。 通过下一代测序、体内测序的强大组合来应对呼吸道病毒感染 新生小鼠感染模型和一种创新的原代新生肺上皮细胞培养方法。体内的关键 将确定新生儿和成人、幼稚和流感感染的C57BL/6和 干扰素αβR-/-流式细胞仪纯化小鼠肺II型上皮细胞。我们还将定义特定年龄的I型干扰素动力学 促进新生儿流感感染肺上皮细胞氧化应激反应的差异 这对致病性有贡献。最后，我们将测试抗氧化剂(N-乙酰半胱氨酸)是否合理 在这一极其脆弱的人群中治疗婴儿呼吸道病毒感染的治疗选择。

Project Summary/Abstract Respiratory viral infections contribute substantially to global infant losses and disproportionately affect preterm neonates. Of all deaths less than 12 months of age secondary to a respiratory viral infection, 55% occur in a neonate born before 30 weeks gestation. Until recently, most research about neonatal and infant primary immune response to viral infections was based on data from adult animal models generalized to the neonate. Current data suggest that a more relevant model for the human infant is the neonatal mouse because of a similar evolution of the immune system post-birth. We have established a 3-day old murine model of infant influenza virus infection, comparable to a late preterm (34-37 weeks gestation) human neonate. To determine age-specific differences in the initial innate response to influenza virus, we measured by Nanostring technology RNA transcriptional changes in 753 immune-related genes induced in neonatal and adult whole lungs 12 hours after PR8 influenza virus infection and uninfected age-matched neonates. Twelve hours after infection, the neonatal mouse had a similar transcriptional profile to an uninfected age-matched mouse, whereas the infected adult mouse upregulated hundreds of genes, especially in the type I interferon (IFN) pathway, an essential component of antiviral defense. Although type I IFNs induce key antiviral pathways, IFNs can also serve to amplify proinflammatory responses, which can increase damage in the respiratory tract in adults. However, the infant-specific type I IFN kinetic and whether type I IFNs are protective or deleterious to infants represents a significant knowledge gap. In preliminary studies, neonatal mice devoid of the type I IFN receptor (IFNαβR-/-) had a greatly improved survival rate of 80% after influenza virus infection, compared to the C57BL/6 survival rate of only 15%. This is in direct opposition to adult mice, where viral infection is more pathogenic in the absence of a type I IFN response. We hypothesize that the neonate has an aberrant type I IFN kinetic in response to influenza virus which directly leads to oxidative stress, inflammation and lung tissue damage. Since the presence of IFNαβ receptor is protective in adults, we also hypothesize that differences in neonatal IFNαβ receptor-dependent responses may involve distinct downstream pathways than the adult type I IFN response. To test this hypothesis, we propose to investigate developmental differences in the infant response to respiratory viral infection through a powerful combination of next generation sequencing, an in vivo neonatal mouse infection model and an innovative primary neonatal lung epithelial cell culture. Key in vivo transcriptome differences will be determined in neonatal and adult, naïve and influenza-infected, C57BL/6 and IFNαβR-/- FACS purified murine lung Type II epithelial cells. We will also define age-specific type I IFN kinetic differences which promote an oxidative stress response in neonatal influenza-infected lung epithelial cells which contributes to pathogenicity. Finally, we will test if an anti-oxidant (N-acetyl cysteine) is a reasonable therapeutic option to treat infant respiratory viral infection in this extremely vulnerable population.