Investigating the role of CaV1.2 in aortic valve stenosis

钙化性主动脉瓣疾病（CAVD）是一种进行性危及生命的疾病，其特征在于营养不良和/或 瓣膜细胞（VIC）的成骨转化，均导致钙化。没有任何医学疗法 预防或延缓CAVD。基于最近对全基因组关联研究的荟萃分析， 出乎意料地鉴定出CACNA 1C，编码电压门控L型钙离子通道的成孔α亚基。 通道CaV 1.2作为CAVD易感基因的候选基因，我们提出的初步数据表明，Ca 2 + VIC中通过CaV1.2的内流是CAVD的原因。这就提出了一种诱人的可能性，即临床上使用的Ca 2 + 通道拮抗剂（CCBs）可能是一种有效的治疗方法。虽然CCB通常禁忌于 对于严重CAVD患者，它们将是疾病过程早期的合理治疗。我们建议 检验以下总体假设：1）VIC中通过CaV1.2增加的Ca 2+内流导致营养不良和/或 成骨转化;和2）通过CaV1.2与CCB和/或通过靶向Ca 2 +- VIC中CaV1.2下游的依赖性信号分子延迟CAVD进展。我们开发了新的 小鼠模型和创新的维克培养物来检验这些总体假设，目的如下：目的1： 通过CaV1.2升高的Ca 2+内流激活VIC和/或增加信号通路基因的表达， 营养不良或成骨钙化的可能性吗使用通过转染增强的猪和小鼠VIC 信息cDNA，我们已经开发出方法来剖析下游的Ca 2+依赖性信号通路 CaV1.2与CAVD的关系，从而发现新的潜在治疗靶点。我们提出了一个 识别关键下游Ca 2+依赖性信号分子和途径的多管齐下的方法 导致营养不良性VIC的活化和/或VIC的成骨转化;目的2：Can抑制CaV1.2 主动脉瓣中的信号通路减少了瓣膜病变？用新的小鼠模型， 在人类CAVD中CaV1.2表达和信号传导增加，我们建议测试CCB是否改善瓣膜病变 一旦钙化开始，就可以逆转疾病进程。我们进一步建议， 目标1中的新候选目标，以测试操纵这些目标是否类似地减少或减缓CAVD 进展目的3：在高脂血症的背景下，通过CaV1.2的过量Ca 2+内流是否有助于CAVD？ 高血压是一个突出的CAVD风险因素。在冠状动脉疾病，一种相关的疾病，长期被忽视的数据， 指出CaV1.2和高脂血症之间的协同相互作用。我们建议：用新型小鼠进行试验 模型是否Ca 2+通过VIC或巨噬细胞中的CaV1.2内流加速AoV病变， 高脂血症，以及作为必然结果，当疾病过程由以下因素驱动时，CCB是否有效 2途径，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.