The Role of macrophages in chorioamnionitis and group B streptococcal infections

绒毛膜羊膜炎(CAM)，或胎膜炎症，通常是细菌上升的结果 感染，是早产、新生儿败血症以及长期残疾和发病率的主要因素 在婴儿身上。不幸的是，CAM通常是无症状的，不容易及时诊断，以防止母体和 胎儿不良结局。这个问题的解决受制于对疾病早期步骤的有限了解 发病机制。尽管它的结构相对简单，但令人惊讶的是，人们对胎膜是如何 参与对潜在病原体的免疫防御。定义先天的细胞和分子基础 膜内免疫有望揭示可操作的、以宿主为基础的诊断、预防 和对CAM的治疗。我们的目标是确定巨噬细胞对胎膜的特定贡献。 免疫学背景下的细菌性CAM由常见的B群链球菌(GBS)引起。 妊娠子宫中的巨噬细胞平衡宿主防御活动和妊娠特异性活动，如 促进胎盘发育，调节母胎免疫耐受。令人着迷的是 母体(蜕膜)和胎儿(胎盘)巨噬细胞都存在于母胎界面，但 它们在先天免疫中的具体作用尚不清楚。我们假设(1)母体和胎儿的巨噬细胞 在细菌感染时对宿主防御和组织炎症反应做出独特的贡献 以及(2)常见的CAM病原体GBS通过抵抗体内的氧化应激来逃避天然免疫 这些巨噬细胞。我们将通过三个目标来检验这一假设。在目标1中，我们将确定 在活体模型中，母体和胎儿的巨噬细胞对CAM的自然历史有哪些贡献 GBS感染呈上升趋势。在目标2中，我们将确定GBS在巨噬细胞内存活的程度 依赖于NADH过氧化物酶(Npx)或其他基因型特异性的细胞内生存防御。 将进行突变研究，以更好地了解npx和其他gbs突变对 活体内的生存能力和疾病，并使用RNA对这一过程中重要的细菌和宿主基因进行分类 测序。将检查更多的基因类型在蜕膜内存活的能力和 胎盘巨噬细胞和持续存在的抗生素通常用于治疗GBS感染。 最后，在目标3中，我们将定义人胎膜内巨噬细胞的旁分泌作用。 在感染期间。为此，我们将采取解构的方法，填充一种微流控、仪表化 含有蜕膜或胎盘巨噬细胞、蜕膜基质细胞、滋养层细胞和 羊膜上皮细胞。我们将验证子假说，即不同的巨噬细胞类型对 抑制未感染膜内的炎症反应并放大对微生物的促炎反应 以特定的方式进行威胁。这些研究将为生殖免疫学提供新的线索，并加速 开发支持健康妊娠的新的诊断、预后和治疗干预措施。

Chorioamnionitis (CAM), or inflammation of the fetal membranes, is often the result of ascending bacterial infection and is a major contributor to premature birth, neonatal sepsis, and long-term disability and morbidity in babies. Unfortunately, CAM is often asymptomatic and not easily diagnosed in time to prevent maternal and fetal adverse outcomes. Solving this problem is hamstrung by a limited understanding of early steps in disease pathogenesis. Despite its relatively simple structure, surprisingly little is known about how fetal membranes participate in immune defense against potential pathogens. Defining the cellular and molecular basis of innate immunity within the membranes promises to reveal actionable, host-based targets for diagnosis, prevention and therapy against CAM. Our objective is to define specific contributions of macrophages to fetal membrane immunology in the context of bacterial CAM caused by the common pathogen Group B Streptococcus (GBS). Macrophages in the gravid uterus balance host defense activities with pregnancy-specific actions such as promoting placental development and governing immune tolerance between mother and fetus. It is fascinating that both maternal (decidual) and fetal (placental) macrophages are present at the maternal-fetal interface, yet their specific roles in innate immunity are unknown. We hypothesize (1) that maternal and fetal macrophages make unique contributions both to host defense and tissue inflammatory responses during bacterial infection and (2) that the common CAM pathogen, GBS, evades innate immunity by resisting the oxidative stress within these macrophages. We will test this hypothesis through three Aims. In Aim 1 we will determine the extent to which maternal and fetal macrophages contribute to the natural history of CAM in vivo using a model of ascending GBS infection. In Aim 2 we will identify the extent to which GBS survival within macrophages depends upon the NADH peroxidase (npx) or other genotype-specific intracellular survival defenses. Mutagenesis studies will be conducted to better understand the impact of npx and other GBS mutations on survivability and disease in vivo, and to classify bacterial and host genes important for the process using RNA sequencing. Additional genotypes will be examined for variation in the ability to survive inside decidual and placental macrophages and persist in the presence of antibiotics commonly used to treat GBS infections. Lastly, in Aim 3 we will define the paracrine contribution of macrophages within the human fetal membrane during infection. For this aim, we will take a deconstructive approach, populating a microfluidic, instrumented fetal membrane-on-chip with decidual or placental macrophages, decidual stromal cells, trophoblasts and amnion epithelial cells. We will test the sub-hypothesis that distinct macrophage types contribute uniquely to inflammatory quiescence within uninfected membranes and amplify proinflammatory responses upon microbial threat in specific manners. These studies will shed new light on reproductive immunology and accelerate the development of new diagnostic, prognostic, and therapeutic interventions that support healthy pregnancies.