LIPOCORTINS AND ARACHIDONIC ACID RELEASE IN PARTURITION

胎儿膜合成和释放类二十烷酸的反应 胎儿或母体信号可能参与分娩的开始， 人类 然而，发生在羊膜和绒毛膜中的细胞内事件 触发这种反应的因素是不明确的。 花生四烯酸动员 磷脂酶的作用是花生四烯酸合成的关键调节步骤 释放并代谢成催产素类的三尖杉酯碱。 一群 磷脂酶抑制蛋白，脂皮质素（现在称为"膜联蛋白"）， 已被鉴定并与前列腺素产生的控制有关。 这些蛋白质似乎通过紧密结合来调节磷脂酶活性 磷脂（以Ca ++依赖性方式），有效螯合 磷脂酶底物。 我们已经证明，膜联蛋白存在于 人子宫内组织，其活性随分娩而变化。 在 这项建议旨在： 1.识别含有膜联蛋白的细胞类型和细胞内 之前获得的人羊膜和绒毛膜中膜联蛋白的定位， 分娩开始后， 2.定量人羊膜和绒毛膜中存在的膜联蛋白的量 在分娩开始之前和之后， 劳动， 3.描述膜联蛋白相互作用的亲和力和特异性 与膜磷脂的相互作用，特别是与 磷脂酰乙醇胺和磷脂酰肌醇（其被水解 在分娩期间释放花生四烯酸）， 4.鉴定与磷脂结合的特性，二价 阳离子和细胞骨架蛋白，以确定膜联蛋白与最高 对磷脂酰肌醇和磷脂酰乙醇胺的亲和力，和 5.体外改变膜联蛋白的位点特异性磷酸化， 对它们活性的影响， 去磷酸化膜联蛋白（具体目标3和4）。 这将决定 膜联蛋白是否有资格作为代谢途径的磷蛋白介质 （前列腺素生产的控制），通过测试它们是否满足 Krebs提出的磷酸化控制标准。 一旦胎儿发生特定膜联蛋白的生化变化， 在分娩开始时的膜被识别，定义的变化可以是 用于评估分娩的候选信号，并评估 在生化水平上的治疗干预的有效性， 目标在于鉴定可能用于预防的药剂 早产儿

Synthesis and release of eicosanoids by fetal membranes in response to fetal or maternal signals may be involved in the onset of parturition in humans. However, the intracellular events occurring in amnion and chorion which trigger this response are ill-defined. Mobilization of arachidonic acid by phospholipase(s) is a key regulatory step in arachidonic acid release and metabolism into oxytocic prostaglandins. A group of phospholipase inhibitory proteins, the lipocortins (now called "annexins"), have been identified and implicated in control of prostaglandin production. These proteins appear to regulate phospholipase activity by binding tightly to phospholipids (in a Ca++ dependent manner), effectively sequestering substrate from phospholipase. We have shown that annexins are present in human intrauterine tissues and that their activity changes with labor. In this proposal, we aim to: 1. Identify the cell types that contain annexins and the intracellular localization of annexins in human amnion and chorion obtained before and after the onset of labor, 2. Quantitate the amount of annexins present in human amnion and chorion before and after the onset of labor to establish changes which occur with labor, 3. Characterize the affinity and specificity of interaction of annexins with membrane phospholipids, particularly the interactions with phosphatidyl ethanolamine and phosphatidyl inositol (which are hydrolyzed during labor to release arachidonic acid), 4. Identify the characteristics of binding to phospholipid, divalent cations, and cytoskeletal proteins, to identify annexins with highest affinity for phosphatidyl inositol and phosphatidyl ethanolamine, and 5. Alter site-specific phosphorylation of annexins in vitro and measure the effect on their activity compared to the characteristics of dephosphorylated annexins (specific aims 3 and 4). This will determine whether annexins qualify as phosphoprotein mediators of a metabolic pathway (control of prostaglandin production), by testing whether they satisfy the criteria proposed by Krebs for control by phosphorylation. Once the biochemical changes which occur in specific annexins in fetal membranes at the onset of labor are identified, the defined changes can be used to evaluate candidate signals for parturition, and to assess the effectiveness of therapeutic interventions at the biochemical level, targeted toward identification of agents which may be useful in prevention of pre-term labor.