Regulation of Phospholipase A2 in Human Amnion

人羊膜中磷脂酶 A2 的调节

• 批准号: 7006082
• 负责人: LESLIE MYATT
• 金额: $ 33.73万
• 依托单位: UNIVERSITY OF CINCINNATI
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-02-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7006082
• 关键词: amnion; antisense nucleic acid; arachidonate; biological signal transduction; biomarker; birth; clinical research; cytokine; eicosanoid metabolism; enzyme activity; epithelium; fibroblasts; human pregnant subject; hypoxia; lipid biosynthesis; mitogen activated protein kinase; peroxisome proliferator activated receptor; phospholipase A2; phosphoproteins; phosphorylation; polymerase chain reaction; premature labor; prostaglandin E; prostaglandin endoperoxide synthase; proteomics; tissue /cell culture; transfection; western blottings

DESCRIPTION (provided by applicant): The amnion is a major site of PGE2 production during labor and is a rich source of arachidonic acid, the precursor of PG production. In the fetal membranes, the amnion fibroblast cells produce approx 50-fold greater PGE2 per cell and overall account for a 5-fold greater production than the amnion epithelium. In the amnion fibroblasts, we have shown glucocorticoids increase PGE2 synthesis by up-regulation of cPLA2 and PGHS-2 enzymes. We described the presence of both the cytosolic and microsomal PGE synthase isoforms (cPGES and mPGES) in fetal membranes but that their expression did not change with gestational age or labor, nor were they induced by glucocorticoid treatment in isolated epithelial or fibroblast cells. The enzymes in the arachidonic acid cascade are now know to be functionally coupled at discrete cellular locations to produce specific PG's. We do not know if cPLA2 and PGHS-2 are coupled to either cPGES or mPGES in amnion cells at labor to produce PGE2. In fetal membranes obtained from patients at term, we observed a punctuate pattern of immunostaining for cPGES and mPGES, identical to that with Sudan Black B, a stain for lipid. Thus these enzymes may localize to lipid bodies (lipid droplets) which are foci for production of eicosanoids in inflammatory cells where cPLA2, PGHS-2, p38 MAP kinase and ERK1, 2 signal transduction molecules are associated with them. Lipid bodies can be lost during tissue or cell fixation possibly accounting for the previous absence of recognition in fetal membranes. Adipophilin and perilipin are found in association with lipid droplets perhaps serving structural and functional roles in various cell types. Both adipophilin and perilipin expression are upregulated by ligands to the transcription factor PPAR-gamma. We have demonstrated increasing adipophilin expression in the human fetal membranes throughout gestation, apparently in association with lipid bodies. Adipophilin was recently shown to be inducible by hypoxia and it is possible that in the avascular fetal membranes hypoxia may regulate adipophilin expression. The hypotheses to be tested are that either cPGES or mPGES are functionally coupled to cPLA2, and PGHS-2 to produce PGE2 at labor, that this may occur in lipid droplets, which are sites of accumulation of enzymes involved in eicosanoid synthesis including, cPLA2, PGHS-2, cPGES, mPGES, p38MAP Kinase and ERK1, 2, and that the PPAR-gamma and hypoxia-regulated proteins adipophilin and peripin play key roles in assembly and function of lipid droplets.

描述（由申请人提供）：羊膜是分娩过程中 PGE2 生产的主要场所，并且是花生四烯酸（PG 生产的前体）的丰富来源。在胎膜中，羊膜成纤维细胞每个细胞产生的 PGE2 大约是羊膜上皮细胞的 50 倍，总体产量是羊膜上皮的 5 倍。在羊膜成纤维细胞中，我们发现糖皮质激素通过上调 cPLA2 和 PGHS-2 酶来增加 PGE2 合成。我们描述了胎膜中胞质和微粒体 PGE 合酶亚型（cPGES 和 mPGES）的存在，但它们的表达不随胎龄或分娩而变化，也不是在分离的上皮细胞或成纤维细胞中通过糖皮质激素处理诱导的。现在已知花生四烯酸级联中的酶在离散的细胞位置上功能性耦合以产生特定的PG。我们不知道 cPLA2 和 PGHS-2 是否在分娩时与羊膜细胞中的 cPGES 或 mPGES 偶联以产生 PGE2。在从足月患者获得的胎膜中，我们观察到 cPGES 和 mPGES 的点状免疫染色模式，与苏丹黑 B（一种脂质染色剂）的免疫染色模式相同。因此，这些酶可能定位于脂质体（脂滴），脂质体是炎症细胞中产生类二十烷酸的焦点，其中 cPLA2、PGHS-2、p38 MAP 激酶和 ERK1, 2 信号转导分子与其相关。脂体可能在组织或细胞固定过程中丢失，这可能是胎膜先前缺乏识别的原因。发现 Adipophilin 和 perilipin 与脂滴相关，可能在各种细胞类型中发挥结构和功能作用。转录因子 PPAR-gamma 的配体可上调 adipophilin 和 perilipin 的表达。我们已经证明，在整个妊娠期间，人类胎膜中的亲脂蛋白表达不断增加，这显然与脂质体有关。最近显示，嗜脂蛋白是由缺氧诱导的，并且在无血管胎膜中，缺氧可能调节嗜脂蛋白的表达。 要测试的假设是，cPGES 或 mPGES 在功能上与 cPLA2 和 PGHS-2 偶联，在分娩时产生 PGE2，这可能发生在脂滴中，脂滴是参与类二十烷酸合成的酶的积累位点，包括 cPLA2、PGHS-2、cPGES、mPGES、p38MAP 激酶和 ERK1, 2，并且 PPAR-γ 和缺氧调节蛋白 adipophilin 和 peripin 在脂滴的组装和功能中发挥着关键作用。