Investigating the role of CaV1.2 in aortic valve stenosis

钙化性主动脉瓣病(CAVD)是一种进行性危及生命的疾病，其特征是营养不良和/或 瓣膜细胞(VIC)的成骨转化，两者都会导致钙化。目前还没有治疗方法 预防或延迟CAVD。基于最近对全基因组关联研究的荟萃分析， 意外鉴定为CACNA1C，编码电压门控L钙的致孔α亚单位 通道CaV1.2，作为CAVD的一个候选易感基因，我们提供的初步数据表明， VICS中CaV1.2的流入是CAVD的原因。这增加了临床使用钙离子的诱人可能性 通道拮抗剂可能是一种有效的治疗方法。尽管CCB一般不适用于 对于有严重CAVD的患者，他们会在疾病进程早期进行合理的治疗。我们建议 检验以下总体假设：1)VICS中通过CaV1.2的钙内流增加会导致营养不良和/或 成骨转化；以及2)通过CCBS的CaV1.2和/或通过靶向钙-2来减少钙内流。 VICS中CaV1.2下游的依赖信号分子延缓了CAVD的进展。我们开发了小说 小鼠模型和创新的VIC培养，以检验这些总体假设，目标如下：目标1：可以 通过CaV1.2增加的钙内流激活VICs和/或增加信号通路基因的表达 AOV的营养不良或成骨性钙化？利用转基因增强型猪和小鼠VICs 在信息丰富的cdna中，我们已经开发出方法来剖析下游依赖于钙的信号通路。 从而发现新的潜在治疗靶点。我们提出了一个 多管齐下识别关键的下游钙依赖信号分子和途径 导致营养不良VIC的激活和/或VIC的成骨转化；目的2：CaV1.2的CaN抑制 主动脉瓣中的信号通路是否会降低瓣膜的病理改变？新的鼠标模型模仿 在人类CAVD中CaV1.2表达和信号增加，我们建议测试CCBS是否改善瓣膜病变 一旦钙化开始，就会逆转疾病的进程。我们还建议在我们的身份识别的基础上 来自目标1的新的候选靶点，以测试操纵这些靶点是否类似地减少或减缓CAVD 进步。目的3：在高脂血症的情况下，通过CaV1.2过量的钙内流是否会导致CAVD？ 高脂血症是CAVD的重要危险因素。在冠状动脉疾病，一种相关的疾病，长期被忽视的数据 提示CaV1.2和高脂血症之间存在协同作用。我们建议：用新的小鼠进行测试 VIC或巨噬细胞中钙离子通过CaV1.2内流是否加速AOV损伤的模型 高脂血症以及作为推论，当疾病过程由以下因素驱动时，CCBS是否有效 高脂血症，从而确定靶向CaV1.2途径是否广泛适用于患者。

Calcific aortic valve disease (CAVD) is a progressive life-threatening disorder characterized by dystrophic and/or osteogenic transformation of valve cells (VICs), both leading to calcification. There are no medical therapies to prevent or delay CAVD. Building on a recent meta-analysis of genome-wide association studies that unexpectedly identified CACNA1C, encoding the pore-forming α subunit of the voltage gated L-type calcium channel CaV1.2, as a candidate CAVD susceptibility gene, we present preliminary data suggesting that Ca2+ influx through CaV1.2 in VICs is causal for CAVD. This raises the tantalizing possibility that clinically used Ca2+ channel antagonists (CCBs) may be an effective therapy. Although CCBs are generally contraindicated in patients with severe CAVD, they would be reasonable therapies earlier in the disease process. We propose to test the overall hypotheses that: 1) increased Ca2+ influx through CaV1.2 in VICs leads to dystrophic and/or osteogenic transformation; and 2) reduction of Ca2+ influx through CaV1.2 with CCBs and/or by targeting Ca2+- dependent signaling molecules downstream of CaV1.2 in VICs delays CAVD progression. We developed novel mouse models and innovative VIC cultures to test those overall hypotheses with the following Aims: Aim 1: Can elevated Ca2+ influx through CaV1.2 activate VICs and/or increase expression of signaling pathway genes leading to dystrophic or osteogenic calcification in the AoV? Using porcine and murine VICs enhanced by transfection of informative cDNAs, we have developed means to dissect the Ca2+-dependent signaling pathways downstream of CaV1.2 that contribute to CAVD, and thereby to discover new potential therapeutic targets. We propose a multi-pronged approach to identify the critical downstream Ca2+-dependent signaling molecules and pathways leading to activation of dystrophic VICs and/or osteogenic transformation of VICs; Aim 2: Can inhibition of CaV1.2 signaling pathways in the aortic valve decrease the valve pathology? With novel mouse models that mimic the increased CaV1.2 expression and signaling in human CAVD, we propose to test if CCBs ameliorate valve lesions and reverse the disease process once calcification is initiated. We further propose to build upon our identification of novel candidate targets from Aim 1 to test if manipulating these targets similarly reduces or slows CAVD progression. Aim 3: Does excess Ca2+ influx through CaV1.2 contribute to CAVD in the context of hyperlipidemia? Hyperlipidemia is a prominent CAVD risk factor. In coronary artery disease, a related disorder, long ignored data point to a synergistic interaction between CaV1.2 and hyperlipidemia. We propose: to test with novel mouse models whether Ca2+ influx through CaV1.2 in VICs or macrophages accelerates AoV lesions in the context of hyperlipidemia and, as a corollary, whether CCBs are effective when the disease process is driven by hyperlipidemia, thereby determining whether targeting the CaV1.2 pathway is broadly applicable in patients.