SWELLING ACTIVATED CURRENTS AND MYOCYTE VOLUME IN CHF

CHF 中的膨胀激活电流和心肌细胞体积

• 批准号: 6390844
• 负责人: SIMON H CLEMO
• 金额: $ 29万
• 依托单位: VIRGINIA COMMONWEALTH UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-30 至 2004-08-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6390844
• 关键词: angiotensin II; autocrine; biological signal transduction; cardiac myocytes; catecholamines; cell morphology; cell osmotic pressure; chloride channels; congestive heart failure; disease /disorder model; dogs; growth factor; hormone regulation /control mechanism; laboratory rabbit; mitogen activated protein kinase; paracrine; pathologic process; phosphoprotein phosphatase; protein kinase C; tissue /cell culture; video microscopy; voltage /patch clamp; western blottings

DESCRIPTION (the applicant's description verbatim): Congestive heart failure (CHF) induces significant changes in cardiac myocyte size. Increased myocyte volume (hypertrophy) ultimately requires intracellular accumulation of osmolytes and water. Intracellular osmolarity is regulated in myocytes by multiple mechanisms, including transmembrane flux of ions through channels that are sensitive to changes in cell volume. We discovered that one of these ionic currents, the cell swelling-activated Cl- current (IC,lswell) is chronically activated under isosmotic conditions in ventricular myocytes from dogs with tachycardia-induced and rabbits with aortic regurgitation-induced CHF. Furthermore, we showed that the activity of ICl,swell and cell volume in CHF and control myocytes were regulated by protein kinase C (PKC) and protein phosphatases thought to control phosphorylation of ion channels responsible for lCl,swell. The overall objective is to understand how Icl,swell and cell volume are regulated in volume and pressure overload models of CHF and how hormonal and autocrine-paracrine factors implicated in the genesis of CHF contribute to this regulation. The effects of catecholamines, autocrine-paracrine factors including angiotensin II and cardiotrophin-1, and selected growth factors on Icl,swell and cell volume will be examined. Intracellular signaling pathways, including protein kinase C, tyrosine kinases, mitogen-activated protein kinases, and phosphatases, will be examined to evaluate their influence on lCl,swell and myocyte volume. Perforated patch voltage clamp and digital video microscopy will be used concurrently to quantify ionic currents and their effect on cell volume. Single myocytes isolated acutely from either sham operated or CHF animals will be studied because these cells better reflect the in vivo state during CHF than do cell culture models. Because no single model of CHF fully represents clinical CHF, pressure, tachycardia, and volume overload models of CHF will be used. Where appropriate, the effect of interventions on cell signaling pathways will be confirmed with western blot with phospho-antibodies. The following questions will be addressed: 1. Are lCl,swell behavior and its effect on myocyte volume different in pressure than volume overload CHF? 2. Is Icl,swell activated prior to onset of clinically apparent CHF in pressure and volume overload models? 3. Are lCl,swell and myocyte volume regulated by autocrine-paracrine factors that are important in the genesis of CHF? 4. Do intracellular signaling pathways that are important in CHF influence lCl,swell and myocyte volume? Knowledge of swelling-activated ion currents and how they influence myocyte volume in CHF may provide important insights into the pathophysiology of tachyarrhythmias and contractile and diastolic dysfunction that occur in CHF. Further, this work may lead to new approaches to treat or prevent CHF and thereby, reduce the morbidity and mortality of this common disease.

描述（申请人的逐字描述）：充血性心力衰竭 (CHF) 会引起心肌细胞大小的显着变化。肌细胞增多 体积（肥大）最终需要细胞内积累 渗透剂和水。肌细胞中细胞内渗透压的调节 多种机制，包括离子通过通道的跨膜通量 对细胞体积的变化敏感。我们发现这些离子之一 电流，细胞肿胀激活的 Cl- 电流 (IC,lswell) 长期存在 在等渗条件下激活狗的心室肌细胞 心动过速诱发的兔和主动脉瓣反流诱发的 CHF。 此外，我们还发现 CHF 中 ICl 的活性、膨胀和细胞体积 和对照肌细胞受蛋白激酶 C (PKC) 和蛋白质调节 磷酸酶被认为控制离子通道的磷酸化，负责 lCl，膨胀。 总体目标是了解 Icl、膨胀和细胞体积如何 CHF 的容量和压力超载模型中的调节以及激素和压力如何调节 与 CHF 发生有关的自分泌-旁分泌因素对此有贡献 规定。儿茶酚胺、自分泌-旁分泌因子的影响 包括血管紧张素 II 和心肌营养素-1，以及选定的生长因子 将检查 Icl、膨胀和细胞体积。细胞内信号通路， 包括蛋白激酶C、酪氨酸激酶、丝裂原激活蛋白 将检查激酶和磷酸酶，以评估它们对 lCl、膨胀和肌细胞体积。穿孔贴片电压钳和数字视频 显微镜将同时用于量化离子电流及其 对细胞体积的影响。从任一假手术中急性分离出单个肌细胞 将研究手术或 CHF 动物，因为这些细胞更好地反映 CHF 期间的体内状态与细胞培养模型相比。因为没有单一型号 CHF 完全代表临床 CHF、压力、心动过速和容量 将使用 CHF 的过载模型。在适当的情况下，效果 对细胞信号通路的干预将通过蛋白质印迹得到证实 与磷酸化抗体。 将解决以下问题： 1. lCl、膨胀行为及其对肌细胞体积的影响是否存在不同 压力大于容量超载CHF？ 2. Icl,swell 是否在临床上明显的压力性 CHF 出现之前激活 和容量过载模型？ 3. lCl、肿胀和肌细胞体积是否受自分泌-旁分泌因子调节 哪些因素对于 CHF 的发生很重要？ 4. 对CHF影响重要的细胞内信号通路 lCl、肿胀和肌细胞体积？ 了解肿胀激活离子流及其如何影响肌细胞 CHF 的体积可能为了解 CHF 的病理生理学提供重要见解 CHF 中发生的快速心律失常以及收缩和舒张功能障碍。 此外，这项工作可能会带来治疗或预防慢性心力衰竭和慢性心力衰竭的新方法。 从而降低这种常见疾病的发病率和死亡率。