LIPOCORTINS AND ARACHIDONIC ACID RELEASE IN PARTURITION

胎膜合成和释放二十烷基类化合物对 胎儿或母亲的信号可能参与了分娩的开始 人类。然而，发生在羊膜和绒毛膜的细胞内事件 是什么触发了这一反应，这些定义都不明确。花生四头肌松动 磷脂酶催化的酸(S)是花生四烯酸的关键调控步骤 释放和代谢成催产素前列腺素。一群 磷脂酶抑制蛋白，脂皮质素(现在称为“膜联蛋白”)， 已被发现并与前列腺素生产的控制有关。 这些蛋白质似乎通过紧密结合来调节磷脂酶活性。 对磷脂(以钙离子依赖的方式)，有效地隔离 磷脂酶的底物。我们已经证明膜联蛋白存在于 人类宫内组织，它们的活动随分娩而变化。在……里面 这项建议的目的是： 1.确定含有膜联蛋白的细胞类型和细胞内 膜联蛋白在人羊膜和绒毛膜中的定位 分娩开始后， 2.定量测定人羊膜和绒毛膜中膜联蛋白的含量 在分娩开始之前和之后确定发生的变化 劳工， 3.表征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(它们是水解物 在分娩期间释放花生四烯酸)， 4.鉴定与二价磷脂结合的特征 阳离子和细胞骨架蛋白，以确定最高的膜联蛋白 对磷脂酰肌醇和磷脂酰乙醇胺的亲和力，以及 5.体外改变膜联蛋白的位点特异性磷酸化，并测定 对其活性的影响与其特征相比较 去磷酸化的膜联蛋白(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化蛋白介质 (前列腺素生产的控制)，通过测试它们是否满足 克雷布斯提出的通过磷酸化控制的标准。 一旦胎儿体内特定的膜联蛋白发生生化变化 在分娩开始时识别胎膜，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， 以确定可能对预防有用的药物为目标 早产的风险。

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.