SWELLING ACTIVATED CURRENTS AND MYOCYTE VOLUME IN CHF

描述（申请人逐字描述）：充血性心力衰竭 (CHF)引起心肌细胞大小的显著变化。肌细胞增多 体积（肥大）最终需要细胞内积累 渗透剂和水。细胞内渗透压在肌细胞中由 多种机制，包括离子通过通道的跨膜通量， 对细胞体积的变化很敏感。我们发现其中一种离子 电流，细胞溶胀激活的Cl-电流（IC，lswell）是慢性的 在等渗条件下激活的犬心室肌细胞 家兔主动脉瓣关闭不全诱发CHF。 此外，我们还发现，CHF时ICl活性、肿胀和细胞体积 而对照组心肌细胞则受蛋白激酶C（PKC）和蛋白质 磷酸酶被认为控制离子通道的磷酸化， 一氯，膨胀。 总体目标是了解Icl、溶胀和细胞体积是如何变化的。 调节CHF的容量和压力过载模型，以及激素和 与CHF发生有关的自分泌-旁分泌因子对此有贡献 调控儿茶酚胺、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、溶胀和细胞体积。细胞内信号通路， 包括蛋白激酶C、酪氨酸激酶、丝裂原活化蛋白 激酶和磷酸酶，将进行检查，以评估它们对 lCl、肿胀和肌细胞体积。穿孔膜片钳与数字视频 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假手术中急性分离的单个肌细胞 手术或CHF动物将进行研究，因为这些细胞更好地反映了 在CHF期间体内状态比细胞培养模型更好。因为没有一个模特 充分代表临床CHF、压力、心动过速和容量 将使用CHF的过载模型。在适当情况下， 对细胞信号传导通路的干预将用蛋白质印迹法证实 用磷酸化抗体 将讨论以下问题： 1.在不同的动物中，lCl、膨胀行为及其对肌细胞体积的影响是否不同？ 压力大于容量超负荷CHF？ 2.在临床上明显的CHF发作之前，压力下的Icl，swell是否被激活 和容量过载模型 3. lCl、肿胀和肌细胞体积受自分泌-旁分泌因子调节吗 在CHF的发生中起重要作用 4.细胞内信号通路在CHF中是否起重要作用 lCl、肿胀和肌细胞体积？ 了解肿胀激活离子电流及其如何影响肌细胞 CHF的体积可能为CHF的病理生理学提供重要的见解。 CHF中发生的快速性心律失常以及收缩和舒张功能障碍。 此外，这项工作可能会导致新的方法来治疗或预防CHF， 从而降低这一常见疾病的发病率和死亡率。

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.