Long-term Antihypertensive Therapy by Delivery of the BK Channel Gene to VSMCs

描述（由申请人提供）：原发性高血压是一种多基因疾病，全世界有近10亿人患有该病。它容易导致心脏肥厚、中风和慢性肾衰竭。在接受降压药治疗的个体中，由于高昂的费用、副作用以及经常需要的每日多种药物治疗的不依从性，只有三分之一的人实现了血压控制。因此，血管舒张蛋白的长期表达对于避免日常给药的高成本和不便，以及减少短效降压药引起的血压波动是极为有利的。作为一种候选血管舒张蛋白，主要的兴趣是在血管平滑肌细胞（VSMCs）和其他细胞类型的表面膜中表达的高电导、钙活化的K+ (BK)通道。BK通道被血管内压力升高激活，并作为代偿机制介导血管舒张。因此，我们设想使用腺相关病毒（AAV）递送在动脉VSMCs中过表达BK通道；我们可以建立代偿性扩张蛋白的“通道储备”，提供长期的抗高血压治疗。基于这一前提，本研究探讨了以下假设：腺相关病毒（AAV）通过平滑肌特异性递送BK通道基因是一种长期控制高血压的治疗方法。在令人兴奋的原理证明研究中，我们观察到aav介导的BK通道基因的传递可以使用平滑肌特异性启动子优先靶向血管系统，这种疗法可以降低高血压小鼠的血压。基于这些发现，我们设计了四个特定的目标：优化BK通道基因传递（Aim 1），在两种高血压小鼠模型中评估AAV传递BK通道的降压作用（Aim 2），评估转导的BK通道是否增强了VSMC膜中的K+电流并保持了正常特性（Aim 3），以及评估AAV介导的BK通道在体外和体内的血管扩张益处（Aim 4）。显然，为了减少高血压在普通人群中的发病率，必须在临床护理中引入血管特异性的长期降压治疗。在这方面，我们项目的研究结果表明，使用aav介导的靶向BK通道到动脉VSMCs的递送可以使高血压在疾病的既定阶段正常化，这表明了一种新的降压治疗模式，避免了日常使用降压药物。公共卫生相关性：高血压困扰着7200万美国人和全世界10亿人。大多数患者的血压没有得到控制，因为对药物治疗方案的依从性较低，通常需要每天服用一次或两次短效降压药。该项目探索了一种可能的长期高血压基因治疗方法，使用一种病毒，只需要一次注射就可以将扩张蛋白直接输送到动脉中，以缓解高血压。

DESCRIPTION (provided by applicant): Essential hypertension is a polygenetic disease afflicting nearly 1 billion individuals worldwide. It predisposes to cardiac hypertrophy, stroke and chronic renal failure. Of the individuals offered antihypertensive drugs, only one third achieve blood pressure control due to the high cost, side effects and noncompliance associated with the daily, multi-drug therapy that is often required. In this regard, the long-term expression of vasodilator proteins would be extremely advantageous to avoid the high cost and inconvenience associated with daily drug administration, and also to minimize the blood pressure fluctuations caused by short-acting antihypertensive drugs. Of major interest as a candidate vasodilator protein is the high-conductance, calcium- activated K+ (BK) channel that is expressed in the surface membrane of vascular smooth muscle cells (VSMCs) and other cell types. The BK channel is activated by rises in intravascular pressure, and acts as a compensatory mechanism to mediate vasodilation. Thus, we envision that using adeno-associated viral (AAV) delivery to overexpress the BK channel in arterial VSMCs; we can establish a "channel reserve" of compensatory dilator proteins that will provide long-term antihypertensive therapy. Based on this premise, this proposal explores the hypothesis that: Smooth muscle-specific delivery of the BK channel gene by adeno- associated-virus (AAV) represents a therapy for the long-term control of high blood pressure. In exciting proof- of-principle studies, we observed that AAV-mediated delivery of the BK channel gene can be preferentially targeted to the vasculature using a smooth muscle-specific promoter, and this therapy lowers blood pressure in hypertensive mice. Based on these findings, we have designed four specific aims that will: Optimize BK channel gene delivery (Aim 1), assess the antihypertensive effect of AAV delivery of BK channels in two mouse models of hypertension (Aim 2), evaluate if the transduced BK channels enhance K+ current and retain normal properties in VSMC membranes (Aim 3), and evaluate the vasodilator benefit of AAV-mediated delivery of BK channels in vitro and in vivo (Aim 4). Clearly, in order to reduce the incidence of hypertension in the general population, vascular-specific, long-term antihypertensive treatments must be introduced into clinical care. In this respect, the findings of our project suggest that using AAV-mediated delivery to target BK channels to arterial VSMCs normalizes hypertension in the established phase of the disease, suggesting a new paradigm for antihypertensive treatment that avoids the daily administration of antihypertensive drugs. PUBLIC HEALTH RELEVANCE: Hypertension afflicts 72 million Americans and 1 billion people worldwide. Blood pressure is not controlled in most patients, because of low adherence to a drug regimen that often requires once or twice daily administration of short-acting antihypertensive drugs. This project explores a possible long-term gene therapy for hypertension using a virus that requires only a single injection to deliver a dilator protein directly to arteries to alleviate high blood pressure.