The Role of macrophages in chorioamnionitis and group B streptococcal infections

绒毛膜羊膜炎 (CAM) 或胎膜炎症，通常是细菌上行的结果 感染，是早产、新生儿败血症以及长期残疾和发病的主要原因 在婴儿中。不幸的是，CAM 往往无症状，且不易及时诊断以预防孕产妇和儿童感染 胎儿不良后果。由于对疾病早期步骤的了解有限，解决这个问题受到阻碍 发病机制。尽管其结构相对简单，但令人惊讶的是，人们对胎膜如何运作知之甚少。 参与针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、基于宿主的诊断、预防目标 以及针对 CAM 的治疗。我们的目标是确定巨噬细胞对胎膜的具体贡献 由常见病原体 B 组链球菌 (GBS) 引起的细菌 CAM 的免疫学。 妊娠子宫中的巨噬细胞平衡宿主防御活动与妊娠特异性行为，例如 促进胎盘发育并控制母亲和胎儿之间的免疫耐受。这是令人着迷的 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) 母体和胎儿巨噬细胞 在细菌感染期间对宿主防御和组织炎症反应做出独特的贡献 (2) 常见的 CAM 病原体 GBS 通过抵抗体内的氧化应激来逃避先天免疫 这些巨噬细胞。我们将通过三个目标来检验这个假设。在目标 1 中，我们将确定 使用以下模型，母体和胎儿巨噬细胞对体内 CAM 的自然史有贡献 GBS 上行感染。在目标 2 中，我们将确定 GBS 在巨噬细胞内的存活程度 取决于 NADH 过氧化物酶 (npx) 或其他基因型特异性的细胞内生存防御。 将进行诱变研究，以更好地了解 npx 和其他 GBS 突变对 体内存活率和疾病，并使用 RNA 对对该过程重要的细菌和宿主基因进行分类 测序。将检查其他基因型在蜕膜和蜕膜内生存能力的变化。 胎盘巨噬细胞并在常用于治疗 GBS 感染的抗生素存在下持续存在。 最后，在目标 3 中，我们将定义巨噬细胞在人胎膜内的旁分泌贡献 感染期间。为了这个目标，我们将采取解构性的方法，填充微流体、仪器化的 胎儿膜芯片，带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。我们将测试以下子假设：不同的巨噬细胞类型对 未感染膜内的炎症静止并放大微生物的促炎反应 以特定方式进行威胁。这些研究将为生殖免疫学提供新的线索并加速 开发新的诊断、预后和治疗干预措施以支持健康妊娠。

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.