Lipid signal transduction /oscillatory insulin secretion

脂质信号转导/振荡胰岛素分泌

• 批准号: 6574873
• 负责人: BARBARA E. CORKEY
• 金额: $ 78.02万
• 依托单位: BOSTON MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-30 至 2005-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6574873
• 关键词: 6 phosphofructokinase; adipocytes; biological signal transduction; calcium channel; cell cell interaction; confocal scanning microscopy; electrophysiology; enzyme deficiency; flow cytometry; free fatty acids; gene targeting; genetically modified animals; glycolysis; insulin; laboratory mouse; laboratory rat; lipase; lipids; lipolysis; metabolism; microarray technology; mitochondria; pancreatic islet function; pancreatic islets; proteomics; single cell analysis; voltage gated channel

DESCRIPTION (provided by applicant): Insulin secretion oscillates, possibly due to oscillatory metabolism of glycolysis, mitochondrial energy production, anaplerosis and lipolysis. These oscillations generate important signals underlying oscillations in electrical activity, ion fluxes and, ultimately, secretion. We hypothesize that FFA may participate as coupling factors to synchronize islet metabolic signal transduction and insulin secretion and to provide communication between peripheral fat cells and islets. This may be achieved by recruiting beta cells, increasing synchrony among beta cells or enhancing responsiveness of beta-cells to glucose. We further presume that FFA and their release by hormone sensitive lipase (HSL) generate important signals that regulate insulin secretion in response to fuel stimuli and elevation of cAMP. We predict that animal models deficient in PFK-M (phosphofructokinase-M) or HSL will demonstrate the critical importance of glycolytic and lipolytic pathways in insulin secretion. Aim 1 will determine the effect of FFA on glucose-induced mitochondrial metabolic oscillations of individual cells within the intact islet. The role of endogenous FFA as a signaling molecule will be studied by monitoring the synchronized metabolic activity in the intact HSL deficient islet. Aim 2 will determine the relationship between oscillatory changes in lipid partitioning and lipolysis in beta cells and islets and GSIS and the effect of FFA on these parameters. Intracellular distribution and movement in real time of fluorescent FFA will be monitored using confocal imaging of beta cells and islets. In addition FFA and glycerol release from stimulated cells will be temporally correlated with insulin secretion and measurements made in Aim 1. Aim 3 will test the hypothesis that FFA promote secretion via direct modulation of voltage-gated L-type calcium channels. Aim 4 will test the hypothesis that oscillatory FFA release from fat cells via HSL-mediated lipolysis plays a role in synchronized insulin secretion from islets. Sequential co-perifusion of isolated fat cells and pancreatic islets will be undertaken. Aim 5 will test the hypothesis that regulation of HSL in the R-cell occurs via oscillatory inhibition by long chain-CoA. Aim 6 will study the mechanism whereby HSL-deficiency in beta-cell results in altered GSIS. Aim 7 will test mechanisms of secretory and electrical synchronization in the intact perfused pancreas and its relationship to islet and single cell studies.

描述（由申请人提供）： 胰岛素分泌振荡，可能是由于糖酵解、线粒体能量产生、回补和脂解的振荡代谢。这些振荡产生重要的信号，这些信号是电活动、离子通量以及最终分泌的振荡的基础。我们推测FFA可能作为偶联因子参与同步胰岛代谢信号转导和胰岛素分泌，并提供外周脂肪细胞和胰岛之间的通讯。这可以通过募集β细胞、增加β细胞之间的同步性或增强β细胞对葡萄糖的反应性来实现。我们进一步推测，FFA和它们的释放激素敏感脂肪酶（HSL）产生的重要信号，调节胰岛素分泌的燃料刺激和cAMP的升高。我们预测PFK-M（磷酸果糖激酶-M）或HSL缺陷的动物模型将证明糖酵解和脂解途径在胰岛素分泌中的至关重要性。目的1将确定FFA对葡萄糖诱导的完整胰岛内单个细胞的线粒体代谢振荡的影响。内源性FFA作为信号分子的作用将通过监测完整的HSL缺陷胰岛中的同步代谢活性来研究。目的2将确定β细胞和胰岛中脂质分配和脂解的振荡变化与GSIS之间的关系以及FFA对这些参数的影响。将使用β细胞和胰岛的共聚焦成像监测荧光FFA的真实的时间内的细胞内分布和运动。此外，受刺激细胞的FFA和甘油释放将与胰岛素分泌和目标1中进行的测量在时间上相关。目的3验证FFA通过直接调节电压门控L型钙通道促进分泌的假说。目的4将检验以下假设：通过HSL介导的脂解作用从脂肪细胞振荡释放FFA在胰岛同步分泌胰岛素中起作用。将进行分离的脂肪细胞和胰岛的顺序共灌流。目的5将检验R细胞中HSL的调节通过长链CoA的振荡抑制发生的假设。目的6研究β细胞中HSL缺陷导致GSIS改变的机制。目的7将测试完整灌注胰腺中分泌和电同步的机制及其与胰岛和单细胞研究的关系。