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)可引起心肌细胞大小的显著变化。肌细胞增多 体积(肥大)最终需要在细胞内积累 渗透剂和水。心肌细胞内渗透压的调节是通过 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。我们发现这些离子中的一个 电流，细胞肿胀激活的氯离子电流(IC，Iswell)是慢性的 犬心肌细胞在等渗条件下被激活 心动过速诱发的心动过速和主动脉瓣关闭不全所致的心力衰竭。 此外，我们还发现CHF患者ICL活性、细胞肿胀和细胞体积 对照组心肌细胞受蛋白激酶C(PKC)和蛋白质的调节 被认为控制离子通道磷酸化的磷酸酶负责 LCL，膨胀。 总体目标是了解ICL、肿胀和细胞体积是如何 调节充血性心力衰竭的容量和压力超负荷模型，以及激素和 参与CHF发生的自分泌-旁分泌因子参与了这一过程。 监管。儿茶酚胺、自分泌-旁分泌因子的作用 包括血管紧张素II和心肌营养素-1，以及选定的生长因子 检查ICL、肿胀和细胞体积。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 将检查激酶和磷酸酶，以评估它们对 LCL、肿胀和心肌细胞体积。穿孔膜片电压钳和数字视频 显微镜将同时用于量化离子流和它们的 对细胞体积的影响。从两个假手术组中急性分离出单个心肌细胞 将对手术或CHF动物进行研究，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要好。因为没有一个单一的模型 心衰完全代表临床心衰、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， 对细胞信号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.LCL、肿胀行为及其对心肌细胞体积的影响 压力比容量过载瑞士法郎？ 2.ICL在临床明显的压力充血性心力衰竭发作前是否被激活 和容量过载模型？ 3.LCL、肿胀和心肌细胞体积是否受自分泌-旁分泌因子的调节 在慢性心力衰竭的发生中起重要作用的是什么？ 4.对CHF起重要作用的细胞内信号通路有影响吗？ LCL、肿胀和心肌细胞体积？ 肿胀激活离子电流的知识及其对心肌细胞的影响 充血性心力衰竭的容量可能为了解心力衰竭的病理生理机制提供重要的见解。 心衰时出现的快速性心律失常、收缩和舒张性功能障碍。 此外，这项工作可能导致治疗或预防充血性心力衰竭和 从而降低这一常见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.