Mechanisms and Therapeutic Role of C-terminus of Cav1.3 L-type Calcium Channel in the Heart

在内心，有两种类型的L式的钙离子通道，经典的Cav1.2和小说 特征较少的骑士队1.3。它们都将细胞膜去极化转化为钙。 瞬变并启动兴奋-收缩耦合。有趣的是，Cav1.3在 胎儿和新生儿心脏的室上组织和脑室，但不在脑室 成人的心脏。Cav1.3也有一个延长的C-末端。与此应用程序相关的是我们的 初步数据表明，Cav1.3的C末端是可移动的，具有 自身Cav1.3基因的转录自动增强子。这种独特的内生属性可以是 在心脏情况下产生恢复心脏功能所需的变力力 在退伍军人中非常普遍的失败。在这里，我们将第一次检验这一假设 Cav1.3 C末端可移动片段移位到细胞核将上调 Cav1.3基因在特定启动子区域的表达(S)，从而提供额外的钙进入 进入心肌细胞，改善小鼠心脏模型的心功能 失败了。这一假设将在三个目标中得到验证：目标1：研究基因的调节 Cav1.3的C末端在自然环境中的表达；目的2：确定其机制 Cav1.3 C末端对Cav1.3基因启动子活性的调控；目的3：研究 Cav1.3 C末端在心力衰竭中的潜在治疗作用。研究将在以下时间进行 电生理学(膜片钳和光学标测)、RNA-SEQ、 体内和体外心脏的生化、超声心动图和组织学。调查结果来自 本工作将为Cav1.3 L类钙通道的作用提供一种新的机制 作为传统的离子孔，也作为一种转录因子调节基因表达和细胞 通过其C端起作用。Cav1.3的C末端上调自身基因的能力 可用于开发治疗心力衰竭的新型变力疗法 在退伍军人中很普遍。

In the heart, there are two types of L-type calcium channels, the classical Cav1.2 and the novel less characterized Cav1.3. They both convert cell-membrane depolarization into calcium transients and initiate excitation-contraction coupling. Interestingly, Cav1.3 is expressed in the supraventricular tissue and ventricles of the fetal and neonatal hearts but not in the ventricles of the adult heart. Cav1.3 also has an extended C-terminus. Relevant to this application is that our preliminary data demonstrate that the C-terminus of Cav1.3 is mobile and functions as a transcription auto-enhancer of its own Cav1.3 gene. This unique endogenous property can be leveraged to generate inotropic force necessary to restore cardiac function in the setting of heart failure which is highly prevalent in Veterans. Here we will test, for the first time, the hypothesis that the translocation of the Cav1.3 C-terminus mobile fragment to the nucleus will upregulate Cav1.3 gene expression at specific promoter region(s) and thus provide additional calcium entry into the cardiac myocyte resulting in improved cardiac function in a murine model of heart failure. This hypothesis will be tested in three aims: Aim 1: Investigate the regulation of gene expression by C-terminus of Cav1.3 in a native environment; Aim 2: Determine the mechanisms of Cav1.3 C-terminus regulation of Cav1.3 gene promoter activity; Aim 3: Investigate the potential therapeutic impact of Cav1.3 C-terminus in heart failure. Studies will be carried out by a combination of electrophysiological (patch-clamp and optical mapping), RNA-seq, biochemical, echocardiography and histology, in in-vivo and ex-vivo hearts. The findings from this work will provide a novel mechanism by which Cav1.3 L-type calcium channel acts not only as a conventional ion pore but also as a transcription factor regulating gene expression and cell function via its C-terminus. The ability of the C-terminus of Cav1.3 to upregulate its own gene can be exploited for the development of novel inotropic therapies for heart failure which is prevalent in Veterans.