Mechanism and prevention of lipopolysaccharide-induced early pregnancy complications

项目总结 现有证据表明，宫内和/或母体细菌感染是早产的主要原因。 以及妊娠晚期并发症。目前用于治疗细菌的抗菌和抗炎药物 孕期感染被认为对孕产妇和胎儿健康有害。因此，继续研究 寻找更好的治疗方案，以避免细菌感染引发的妊娠并发症是诱人的。 蜕膜和胎盘位于母体-胚胎交界处，是母体-胚胎界面的第一道线。 对细菌毒素的防御，但其对细菌毒素的防御机制较差 明白了。内毒素(LPS)是革兰氏阴性杆菌的一种内毒素，与 感染导致的妊娠缺陷。细胞表面蛋白对内毒素的识别是 细胞表面分子启动其炎症信号或使其失活。我们的初步结果 建立：1)子宫腔上皮、蜕膜和胎盘表达内毒素传感和信号。 TLR4/CD14/MD2复合体；2)妊娠第5天注射脂多糖可通过 在胚胎着床点选择性激活依赖于MyD88的TLR4信号通路；3) 脂多糖诱导促炎细胞因子基因如肿瘤坏死因子-α和IL-1β的表达，趋化因子基因如 CXCL1&2和中性粒细胞向EIS募集；4)蜕膜和胎盘细胞表面表达组织- 能去磷酸化内毒素的非特异性碱性磷酸酶(TNAP)同工酶；5) 去磷酸化的内毒素对小鼠妊娠无炎性和无毒性；6)AP同工酶治疗 减轻脂多糖诱导的小鼠早孕丢失。这些初步发现导致了这一假设 在EIS早期，脂多糖诱导的微环境破坏是由 常驻蜕膜细胞和招募的中性粒细胞，以及通过补充和/或内毒素解毒 诱导TNAP的产生/活性可能会消除内毒素介导的早期妊娠缺陷/丢失。 为了检验我们的假设，我们提出了三个机械论目标。在目标1中，我们将使用Cre-lox和抗体- 介导性中和技术确立了内毒素诱导发展的重要一步 早期EIS的不良炎症是蜕膜细胞类型依赖的炎性募集 中性粒细胞。在目标2中，我们将产生新的具有子宫tnap基因alp1缺失的雌性小鼠来确定 子宫内源性TNAP缺乏是否会增强对内毒素的反应。在目标3中，我们将研究 三磷酸腺苷及其激活剂或诱导剂在减轻脂多糖或大肠杆菌诱导的早孕中的作用 缺陷/损失。 在完成这些目标后，我们希望获得：1)感染诱导机制的洞察力 2)开发一种新的内毒素解毒治疗策略，以避免细菌- 诱发早孕并发症。

PROJECT SUMMARY The available evidence suggests that intrauterine and/or maternal bacterial infection is a major cause of early and late pregnancy complications. Current antibacterial and anti-inflammatory drugs used to treat bacterial infection during pregnancy are considered harmful to maternal and fetal health. Thus, continued research to look for better treatment options to avoid bacterial infection-induced pregnancy complications is alluring. The decidua and placenta are uniquely positioned at the maternal-embryonic interface to serve as a first line of defense against bacterial toxins, but their defensive mechanisms against bacterial toxins are poorly understood. Lipopolysaccharide (LPS) is an endotoxin of Gram-negative E. coli that is associated with infection-induced pregnancy defects. LPS recognition by cell surface proteins is an important step required for the initiation of its inflammatory signaling or inactivation by cell surface molecules. Our preliminary results establish that: 1) the uterine luminal epithelium, decidua and placenta express the LPS sensing and signaling TLR4/CD14/MD2 complex; 2) LPS injection on day 5 of pregnancy terminates pregnancy by day 8 via selective-activation of the MyD88-dependent TLR4 signaling pathway at the embryo implantation site (EIS); 3) LPS induces expression of proinflammatory cytokine genes such as Tnf-α & Il-1β, chemokine genes such as Cxcl1&2, and neutrophil recruitment to the EIS; 4) cell surfaces of the decidua and placenta express tissue- nonspecific alkaline phosphatase (TNAP) isozyme that is capable of dephosphorylating LPS; 5) dephosphorylated LPS is non-inflammatory and non-toxic to murine pregnancy; and 6) AP isozyme treatment alleviates LPS-induced early pregnancy loss in mice. These preliminary findings have led to the hypothesis that LPS-induced microenvironment disruption at the early EIS is a result of concerted action of resident decidual cells and recruited neutrophils, and LPS detoxification by supplementation and/or induction of TNAP production/activity may abrogate LPS-mediated early pregnancy defects/loss. To test our hypothesis, we have proposed three mechanistic aims. In Aim 1, we will use Cre-lox and antibody- mediated neutralization technologies to establish that an important step in the development of LPS-induced unwanted inflammation at the early EIS is decidual cell-type-dependent recruitment of inflammatory neutrophils. In Aim 2, we will generate novel female mice with uterine deletion of TNAP gene Alpl to determine whether endogenous TNAP deficiency in the uterus augments the response to LPS. In Aim 3, we will examine the potential of TNAP and its activator or inducer in mitigating LPS- or E. coli-induced early pregnancy defects/loss. Upon completion of these aims, we hope to gain: 1) insights into the mechanisms of infection-induced inflammation at the early EIS; and 2) develop a novel LPS-detoxification therapeutic strategy to avoid bacteria- induced early pregnancy complications.