PHOSPHOLIPID SIGNALLING MECHANISMS IN CARDIOMYOCYTES

心肌细胞中的磷脂信号传导机制

• 批准号: 3339536
• 负责人: JOAN HELLER BROWN
• 金额: $ 16.67万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 1982
• 资助国家: 美国
• 起止时间: 1982-08-01 至 1995-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3339536
• 关键词: alpha adrenergic receptor; angiotensin II; atrial natriuretic peptide; calcium channel; calcium flux; chick embryo; croton oil; diacylglycerols; endothelin; enzyme activity; enzyme induction /repression; gallamine triethiodide; gene expression; genetic transcription; guanosine triphosphate; heart cell; heart conduction system; heart contraction; heart pharmacology; heart rate; hormone regulation /control mechanism; laboratory rat; muscarinic receptor; newborn animals; phosphatidylcholines; phosphatidylinositols; protein kinase C; radiotracer; second messengers; secretion; thrombin; tissue /cell culture; tritium; ventricular hypertrophy

The long term objective of our research continues to be to understand the mechanisms by which extracellular signals are transduced into cellular responses in the heart. In this renewal the title of the grant has been changed to more specifically reflect the focus of this proposal. The central hypothesis is that membrane phospholipids, particularly phosphatidylinositides (PI) and phosphatidylcholine (PC) are hydrolyzed in response to hormones and generate products that serve as second messenger mediating cardiac responses. Studies will be carried out in primary cultures of cardiomyocytes prepared from embryonic chick, adult rat and neonatal rat heart. A number of cardioactive hormones, including muscarinic and alpha1-adrenergic receptor agonists, angiotensin II, thrombin and endothelin stimulate PI hydrolysis in these cells. These agents have not been directly shown to stimulate diacylglycerol (DAG) formation or to activate protein kinase C (PKC). Also unknown is whether these hormones induce PC hydrolysis. The specific aims of this proposal are to determine 1) whether agonists stimulate PC hydrolysis in myocytes, what phospholipases are activated, and by what molecular mechanisms (GTP- binding protein, activation through protein kinase) 2) if DAG is increased, if there is a significant basal or hormone stimulated level of ether-linked (particularly alkeny- acyl- or plasmalogenic) diglycerides, and if there is a significant contribution of PC to diglyceride formation 3) if the activation of PKC can be demonstrated by intact cell [3H]-PDB binding, by enzyme activation in permeabilized cells or by redistribution of immunoreactive PKC protein 4) the possible role of phospholipid generated second messengers in leading to c-fos induction and increases in specific gene expression in neonatal ventricular myocyte and in leading to ANF secretion in atrial myocytes. If cardioactive hormones stimulate the generation of phospholipid-derived second messengers that mediate ANF secretion or cause alterations in gene transcription like those seen in hypertrophy, the basic mechanisms leading to pathological changes in these functions may be clarified and may prove to be amenable to pharmacological treatment.

我们研究的长期目标继续是了解 细胞外信号转导为细胞的机制 心脏的反应。 在此续签中，赠款的标题是 更改为更具体地反映了该提案的重点。 这 中心假设是膜磷脂，特别是 磷脂酰肌醇（PI）和磷脂酰胆碱（PC）被水解在 对激素的反应并生成用作第二使者的产品 介导心脏反应。 研究将在初级 由胚胎小鸡，成年大鼠和 新生儿大鼠心脏。 许多心活性激素，包括 毒蕈碱和α1-肾上腺素能受体激动剂，血管紧张素II， 凝血酶和内皮素刺激这些细胞中的PI水解。 这些 尚未直接证明药物刺激二酰基甘油（DAG） 形成或激活蛋白激酶C（PKC）。 也未知是是否 这些激素诱导PC水解。 该提议的具体目的 确定1）激动剂是否刺激肌细胞中的PC水解， 哪种磷脂酶是被激活的，以及通过什么分子机制（GTP- 结合蛋白，通过蛋白激酶的激活）2）如果DAG增加，则 如果存在明显的基底或激素刺激的醚连接水平 （尤其是烷基酰基或浆原性的）甘油二酸酯，以及是否存在 PC对甘油三酸酯形成的重要贡献3）如果 PKC的激活可以通过完整的细胞[3H] -PDB结合来证明 透化细胞中的酶激活或通过重新分布 免疫反应性PKC蛋白4）产生磷脂的可能作用 第二个使者导致C-FOS诱导并增加 新生儿心肌细胞和导致ANF的基因表达 心肌细胞中的分泌。 如果心活性激素刺激 介导ANF的磷脂衍生的第二信使产生 分泌或引起基因转录的改变，如在 肥大，是导致病理学变化的基本机制 可以阐明功能，并可能被证明是药理的 治疗。