REGULATION OF CARDIAC CONTRACTILITY BY DIACYLGLYCEROL

摘要。该研究的长远目标是阐明二酰基甘油和蛋白激酶c调控心肌收缩的机制。许多细胞外化学信号，如激素、神经递质、细胞因子、生长因子、机械应力和氧应激，可能通过动员脂质第二信使（包括二酰基甘油和顺式不饱和脂肪酸）来调节心脏收缩。至少有四种酶系统，PLA2, plc - β， plc - γ和PLD参与产生这些脂质信使，产生在脂质物种中编码的潜在的富含信息的信号，这些脂质信使产生在脂质物种中编码的潜在的富含信息的信号，以系统的方式定时和定位，以建立这些参数对收缩调节的影响。顺式不饱和脂肪酸和Ca将与二酰基甘油作为可能选择性激活蛋白激酶C亚型α， ε或δ的推定共信使进行研究。我们将研究蛋白激酶C锚定在横小管和肌丝上的机制，并确定它们在调节收缩期钙水平和肌丝钙敏感性中的作用。蛋白激酶C介导的心肌肌钙蛋白I磷酸化是否是心室肌细胞正性或负性肌力反应的主要机制也将被确定。目标是结合细胞生物物理学、成像和分子生物学的现代和创新方法，为心脏中二酰基甘油信号传导的基本问题提供明确的答案。本研究将进一步了解脂质信使改变心脏生理的基本机制，以及蛋白激酶C调控心肌肌钙蛋白I功能的机制，从而发现和纠正各种疾病状态下这些通路的缺陷。拟议的研究将与其他子项目高度互动，并将在很大程度上依赖于该计划中其他研究人员的专业知识。总的来说，本研究解决了该计划的一个主要主题，涉及阐明膜受体拮抗剂在心肌中引起的信号转导机制。

Abstract. The broad, long-term objectives of the proposed research are to elucidate mechanisms underlying the regulation of myocardial contraction by diacylglycerol and protein kinase C. Many extracellular chemical signals such as hormones, neurotransmitters, cytokines, growth factors, mechanical stress and oxygen stress may regulate cardiac contractility by mobilizing lipid second messengers including diacylglycerol and cis- unsaturated fatty acids. There are at least four enzyme systems, PLA2, PLC-beta, PLC-gamma and PLD involved in generating these lipid messengers giving rise to a potentially information-rich signal encoded in lipid species generating these lipid messengers giving rise to a potentially information-rich signal encoded in lipid species, timing and location in a systematic way in order to establish the influence of these parameters on contractile regulation. cis-Unsaturated fatty acids and Ca will be investigated as putative co-messengers with diacylglycerol that may selectively activate protein kinase C isoforms alpha, epsilon or delta. The mechanisms of protein kinase C anchoring to sites on the transverse tubules and to sites on the myofilament will be examined and their respective roles in regulating systolic Ca levels and myofilament Ca sensitivity will be established. Whether protein kinase C mediated phosphorylation of cardiac troponin I is a major mechanism underlying positive or negative inotropic responses in ventricular myocytes will also be established. The goal is to use a combination of modern and innovative methodologies in cell biophysics, imaging and molecular biology to provide unambiguous answers to fundamental questions about diacylglycerol signaling in the heart. This research will further our understanding of basic mechanisms by which lipid messengers alter cardiac physiology, and mechanisms of protein kinase C regulation of cardiac troponin I function, so that defects in these pathways in various diseased states can be identified and corrected. The proposed research will be highly interactive with other subprojects and will rely to a significant extent on the expertise of other investigators in the Program. Overall, this research addresses a major theme of the Program involving elucidation of signal transduction mechanisms evoked by membrane receptor antagonists in myocardium.