Mechanisms regulating fetal membrane and neutrophil responses to infection

调节胎膜和中性粒细胞对感染反应的机制

• 批准号: 10876528
• 负责人: Vikki M Abrahams
• 金额: $ 40.4万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-03 至 2024-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10876528
• 关键词: Acetylmuramyl-Alanyl-Isoglutamine; Agonist; Allopurinol; Bacteria; Bacterial Infections; Cells; Chemotactic Factors; Communication; Complex; Data; Exposure to; Family; Fetal Membranes; Fetus; Grant; Human; IL8 gene; Immune; In Vitro; Infection; Inflammasome; Inflammation; Inflammatory; Inflammatory Response; Lipopolysaccharides; Maternal-Fetal Exchange; Mediating; Mediator; MicroRNAs; Modeling; Mus; Nature; Neutrophil Activation; Neutrophil Infiltration; Outcome; Pathologic; Pathology; Pattern recognition receptor; Peptidoglycan; Play; Pregnancy; Pregnancy Complications; Premature Birth; Process; Production; Regulation; Risk; Risk Factors; Role; Signal Pathway; Signal Transduction; Site; Source; TLR2 gene; TLR4 gene; TLR7 gene; TLR8 gene; Testing; Tissue membrane; Toll-like receptors; Uric Acid; Woman; Xanthine Oxidase; chemokine; cytokine; exosome; extracellular; in vitro testing; in vivo; inflammatory milieu; inhibitor; intraamniotic infection; mouse model; neutrophil; novel; premature; receptor; response; sensor; therapeutic target; tissue injury; xanthine oxidase inhibitor

Summary/Abstract Chorioamnionitis - inflammation of the fetal membranes (FM) - is characterized by neutrophil infiltration and is a major risk factor for preterm birth. Even in the absence of prematurity, chorioamnionitis can be detrimental to the fetus. Despite a strong association between bacterial infection, chorioamnionitis, and preterm birth, the mechanisms involved are not fully understood. Through expression of the innate immune pattern recognition receptors (PRR), Toll-like receptors (TLRs) and Nod-like receptors (NLRs), FMs have strategies to evade and protect against infection. However, depending upon the nature of signaling and regulation, these protective immune mechanisms may create an inflammatory milieu that can contribute to pathology. In particular, IL-8 is a major neutrophil chemoattractant and inflammasome-mediated IL-1b is a major inducer of tissue injury and mediator of preterm birth. We have found that the chorionic compartment is the primary site of FM IL-8 and IL- 1b production in response to bacterial lipopolysaccharide (LPS), peptidoglycan (PDG), and muramyl dipeptide (MDP) which activate TLR4, TLR2, and Nod2, respectively. While TLRs and NLRs can directly activate signaling pathways leading to inflammatory cytokine/chemokine production, there is the potential for far more complex modulation, regulation, and fine-tuning of these processes and the type of responses generated, particularly for IL-1b. This grant focusses on the requirement of two or more PRRs to be activated sequentially in FMs exposed to bacterial triggers via novel intermediates. A non-classical family of microRNAs (miRs) activate the ssRNA sensors, TLR7 and TLR8, to elicit an inflammatory response. These miRs can also be carried in exosomes and delivered to TLR7 or TLR8 in target cells. Our preliminary data supports the concept that TLR8-activating miR-146a-3p may acts as a novel intermediate signal that drives FM chemotactic and inflammatory responses to bacterial TLR and NLR agonists. We also have preliminary data demonstrating that FM-derived exosomes containing TLR8-activating miRs trigger neutrophil activation and release of neutrophil extracellular traps. Finally, we found that FM tissue and circulating exosomal TLR8-activating miR-146a-3p is elevated in women with preterm birth. Based on this, our central hypothesis is that TLR8-activating miRs mediate FM chemotactic IL-8 and inflammasome-mediated inflammatory IL-1b in response to bacterial triggers, and through their release and delivery via exosomes active maternal neutrophils. This leads to inflammation at the maternal-fetal interface, increasing the risk for chorioamnionitis. To test this, our specific aims are to determine if: Aim 1. TLR8-activating miRs mediate a FM chemotactic IL-8 response after exposure to bacterial triggers. Aim 2. TLR8-activating miRs contribute to FM inflammasome activation and inflammatory IL-1b production. Aim 3. FM exosomes containing TLR8-activating miRs induce neutrophil activation.

摘要/摘要 绒毛膜羊膜炎——胎膜炎症（FM）——以中性粒细胞浸润为特征， 早产的主要危险因素。即使没有早产，绒毛膜羊膜炎也可能对胎儿造成损害。 胎儿。尽管细菌感染、绒毛膜羊膜炎和早产之间存在密切关联， 所涉及的机制尚不完全清楚。通过表达先天免疫模式识别 受体（PRR）、Toll 样受体（TLR）和 Nod 样受体（NLR），FM 具有逃避和防御策略 防止感染。然而，根据信号传导和调节的性质，这些保护性 免疫机制可能会产生导致病理的炎症环境。特别地，IL-8是 主要的中性粒细胞趋化剂和炎症小体介导的 IL-1b 是组织损伤和 早产的中介者。我们发现绒毛膜室是 FM IL-8 和 IL-的主要位点。 1b 响应细菌脂多糖 (LPS)、肽聚糖 (PDG) 和胞壁酰二肽而产生 (MDP) 分别激活 TLR4、TLR2 和 Nod2。而TLR和NLR可以直接激活 导致炎症细胞因子/趋化因子产生的信号通路，还有更多的潜力 这些过程的复杂调制、调节和微调以及生成的响应类型， 特别是对于 IL-1b。该补助金重点关注两个或多个 PRR 依次激活的要求 在通过新型中间体暴露于细菌触发物的 FM 中。非经典的 microRNA (miR) 家族 激活 ssRNA 传感器 TLR7 和 TLR8，引发炎症反应。这些 miR 也可以 携带在外泌体中并递送至靶细胞中的TLR7或TLR8。我们的初步数据支持这个概念 TLR8 激活 miR-146a-3p 可能作为一种新型中间信号驱动 FM 趋化和 对细菌 TLR 和 NLR 激动剂的炎症反应。我们还有初步数据表明 含有 TLR8 激活 miR 的 FM 衍生外泌体可触发中性粒细胞激活和中性粒细胞释放 细胞外陷阱。最后，我们发现 FM 组织和循环外泌体 TLR8 激活 miR-146a-3p 是 早产女性中升高。基于此，我们的中心假设是 TLR8 激活 miR 介导 FM 趋化性 IL-8 和炎症小体介导的炎症性 IL-1b 对细菌的反应 触发因素，并通过外泌体释放和递送活跃的母体中性粒细胞。这导致 母胎界面炎症，增加绒毛膜羊膜炎的风险。为了测试这一点，我们的 具体目标是确定是否： 目标 1. TLR8 激活 miR 在暴露于细菌触发物后介导 FM 趋化性 IL-8 反应。 目标 2. TLR8 激活 miR 有助于 FM 炎症小体激活和炎症 IL-1b 产生。 目标 3. 含有 TLR8 激活 miR 的 FM 外泌体诱导中性粒细胞激活。