Understanding the Impact of Influenza A Virus Infection During Pregnancy

项目总结 成功的怀孕与复杂的免疫平衡有关，这种平衡对支持 外来胎儿的存在和发育。这种平衡以生理变化为标志，这些变化可以改变 肺间室，包括增加氧气消耗的需要，这可能会影响怀孕 女性对呼吸道感染的反应。例如，在怀孕期间感染甲型流感病毒(IAV)是 更有可能导致严重疾病，包括住院甚至死亡。在2009年大流行期间，29% 与流感相关的住院病例中，高达16%的死亡病例发生在孕妇身上。母体IAV 感染也会对后代产生负面影响，包括自然流产、胎儿死亡、 胎龄小(SGA)和认知功能障碍。尽管有这些有害的结果，但对 潜在的机制仍然很稀少。我们知识中的一个根本差距是理解 不同孕期的肺微环境影响对IAV感染的反应。一个重要的 阻碍这些研究进一步发展的障碍是很难可靠地确定怀孕日期。填补这一空白 据我所知，我使用了一种健壮且可重现的怀孕小鼠模型，在该模型中我使用超声波 分析，以更准确地确定怀孕日期，使我可以在怀孕早期感染怀孕的水坝 (胚胎日(E)8.5)、孕中期(E10.5)和常用的E12.5时间点，代表晚期 怀孕了。我的体内研究表明，孕妇在怀孕早期感染IAV与 与未怀孕感染的小鼠和晚些时候感染的小鼠相比，肺损伤导致的死亡率增加 怀孕，突出阶段依赖的易感性和疾病。在怀孕早期感染的怀孕小鼠中， 我发现肺中隔增厚，细支气管壁剥落，提示肺损伤。 斯特尔玛。在与保罗·托马斯博士的实验室的合作下，我们小组最近展示了 基质细胞在流感应答和修复过程中对肺微环境的调节和重塑 (Boyd等人，《自然》2020)。总而言之，这导致我假设妊娠阶段调节IAV 改变肺微环境的发病机制，包括肺间质细胞的显著变化 人口。我将使用综合方法，包括组织学，基于流式细胞仪的分析，单细胞 基因表达谱(SCEX)和生物信息学。为了解决这一假设，在目标1中，我将进一步评估， 量化并从功能上确定妊娠期如何调节IAV增加的发病机制 怀孕的母亲。目标2将进一步确定妊娠期流感感染对母体肺间质的影响 细胞，这是一个研究严重不足的领域。完成后，这些研究将对关键的 孕期窗口，可以针对最大限度地保护母亲和胎儿免受IAV感染， 包括调整疫苗方案和治疗干预措施。

PROJECT SUMMARY A successful pregnancy is associated with an intricate immunological balance that is crucial in supporting the presence and development of a "foreign" fetus. This balance is marked by physiological changes that can alter the lung compartment, including the need for increased oxygen consumption, which can influence pregnant women's response to respiratory infections. For example, influenza A virus (IAV) infection during pregnancy is more likely to result in severe disease, including hospitalization and even death. During the 2009 pandemic, 29% of influenza-associated hospital admissions and up to 16% of deaths were in pregnant women. Maternal IAV infection can also negatively impact the offspring, including increases in spontaneous abortions, fetal death, small gestational age (SGA), and cognitive dysfunction. Despite these detrimental outcomes, insight into the underlying mechanisms is still sparse. A fundamental gap in our knowledge is understanding how remodeling of the lung microenvironment during distinct gestational stages affects the response to IAV infection. A significant barrier to further these studies has been the difficulty to reliably define gestational dates. To fill this gap in knowledge, I have employed a robust and reproducible pregnant mouse model whereby I use ultrasound analysis to more accurately determine the gestational date allowing me to infect pregnant dams at early gestation (embryonic day (E)8.5), mid-gestation (E10.5) and at the commonly used E12.5 timepoint, which represents late gestation. My in vivo studies have shown that maternal IAV infection during early gestation is associated with increased mortality due to lung damage compared to non-pregnant infected mice and mice infected later in pregnancy, highlighting stage-dependent susceptibility and disease. In pregnant mice infected early in gestation, I found that there is increased septal thickening and denuded bronchioles suggesting damage to the lung’s stroma. In collaboration with Dr. Paul Thomas's laboratory, our group recently demonstrated the critical role for stromal cells in regulating and remodeling the lung microenvironment during response and repair to influenza (Boyd et al., Nature 2020). Collectively, this leads me to hypothesize that the gestational stage modulates IAV pathogenesis by altering the lung microenvironment, including marked changes in the lung's stromal cell populations. I will utilize integrative approaches including histology, flow-cytometry-based assays, single-cell gene-expression profiling (scEX), and bioinformatics. To address this hypothesis, in Aim 1, I will further assess, quantify and functionally determine how gestational stage can mediate increased IAV pathogenesis in the pregnant mother. Aim 2 will further define the impact of gestational influenza infection on maternal lung stromal cells, a severely understudied area. Upon completion, these studies will have major implications on the critical gestational window that could be targeted to maximize protection for the mother and fetus from IAV infection, including restructuring vaccine regimens and therapeutic interventions.