Thrombin-Stimulated Intrauterine Signaling Pathway

描述（由申请人提供）：早产在美国导致8-10%的妊娠并发症，导致新生儿和儿科的严重发病率，约占新生儿死亡率的75%。早产发生的机制尚不清楚；然而，迄今为止的研究表明，早产通常与生殖道感染有关，这与促炎细胞因子（如il - 2、ILa、TNF-a和IFN-g）升高有关。虽然已经证明这些细胞因子导致子宫内组织前列腺素生成增加，但尚不清楚这是否是这些促炎细胞因子导致早产刺激的唯一机制。本RO1申请中描述的研究将验证以下假设：内毒素（LPS）刺激促炎细胞因子增加，特别是IL-2、TNF-a和IFN-g，导致“凝血酶刺激的宫内信号通路”激活；即磷脂超燃酶（PLS）、组织凝血酶原（Fgl2）、凝血酶原和凝血酶受体（PAR1）表达和激活增强，导致早产和分娩。我们的初步研究已经证实了这一途径的所有成分在近期大鼠子宫内的分子表达。利用lps诱导的定时妊娠大鼠早产模型，我们将完成以下具体目的：1)测定早产大鼠子宫中Fgl2表达和激活是否升高，导致凝血酶原活性升高；2)测定早产大鼠子宫中磷脂超燃酶表达和功能活性是否升高，导致Fgl2活性增强；3)测定宫内凝血酶原表达是否升高，导致凝血酶生成增强；5)验证上述现象平行发生的假设，以及前列腺素在lps刺激下大鼠早产和分娩过程中的作用。这些研究预计将显著提高我们对存在宫内感染的早产机制的理解。

DESCRIPTION (provided by applicant): Preterm delivery, which complicates 8-10% of pregnancies in the United States, results in significant neonatal and pediatric morbidity, and is responsible for about 75% of the neonatal mortality. The mechanisms underlying the onset of preterm labor are unclear; however, studies to date suggest that preterm delivery is often associated with genital tract infection, as suggested by elevated proinflammatory cytokines (e.g. IL2, ILa, TNF-a, and IFN-g). Although it has been shown that these cytokines lead to increased prostaglandin production by intrauterine tissues, it is unclear whether this is the only mechanism by which these pro-inflammatory cytokines lead to the stimulation of preterm contractions. The research described in this RO1 application will test the hypothesis: endotoxin (LPS) stimulates increased proinflammatory cytokines, especially IL-2, TNF-a and IFN-g resulting in activation of the "thrombin stimulated intrauterine signaling pathway"; i.e. enhanced phospholipid scramblase (PLS), tissue prothrombinase (Fgl2), prothrombin and thrombin receptor (PAR1) expression and activation leading to preterm contractions and delivery. Our preliminary studies have confirmed the molecular expression of all of the components of this pathway within the near term rat uterus. Using the LPS-induced preterm delivery model in the timed-pregnant rat, we will complete the following specific aims: 1) determine if Fgl2 expression and activation are increased in the preterm rat uterus, leading to prothrombinase activity, 2) determine if phospholipid scramblase expression and functional activity increase in the preterm rat uterus, leading to enhanced Fgl2 activity, 3) determine if increased intrauterine prothrombin expression occurs, leading to enhanced thrombin generation, 4) determine if uterine PAR-1 expression and activation are increased, leading to myometrial contractions, decidual necrosis, and intrauterine bleeding, and 5) test the hypothesis that the above phenomena occur in parallel and contribute to the role of prostaglandins during the events leading to LPS-stimulated preterm labor and delivery in the rat. These studies are anticipated to significantly improve our understanding of the mechanisms underlying preterm labor in the presence of intrauterine infection.