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，困扰着全球近10亿人。它易导致心脏肥大、中风和慢性肾衰竭。在提供抗高血压药物的个人中，只有三分之一的人实现了血压控制，这是由于高成本、副作用和与经常需要的每日多种药物治疗相关的不依从性。在这方面，血管扩张蛋白的长期表达将是极其有利的，以避免与日常药物给药相关的高成本和不便，并且还使由短效抗高血压药物引起的血压波动最小化。作为候选血管扩张蛋白的主要兴趣是在血管平滑肌细胞（VSMC）和其他细胞类型的表面膜中表达的高电导、钙激活的K+（BK）通道。BK通道通过血管内压力升高激活，并作为一种补偿机制介导血管舒张。因此，我们设想，使用腺相关病毒（AAV）交付过表达BK通道在动脉VSMCs，我们可以建立一个“通道储备”的补偿扩张蛋白，将提供长期的抗高血压治疗。基于这一前提，该提议探索了以下假设：通过腺相关病毒（AAV）对BK通道基因的平滑肌特异性递送代表了用于长期控制高血压的疗法。在令人兴奋的原理证明研究中，我们观察到AAV介导的BK通道基因的递送可以使用平滑肌特异性启动子优先靶向脉管系统，并且这种疗法降低了高血压小鼠的血压。根据这些发现，我们设计了四个具体目标，将：优化BK通道基因递送（目的1），评估AAV递送BK通道在两种高血压小鼠模型中的抗高血压作用（目的2），评估转导的BK通道是否增强VSMC膜中的K+电流并保持正常特性（目的3），并在体外和体内评估AAV介导的BK通道递送的血管扩张益处（目的4）。显然，为了降低普通人群中高血压的发病率，必须将血管特异性的长期降压治疗引入临床护理。在这方面，我们的项目的发现表明，使用AAV介导的递送靶向BK通道到动脉VSMCs在疾病的建立阶段使高血压正常化，这表明了一种新的抗高血压治疗模式，避免了每天服用抗高血压药物。公共卫生相关性：高血压困扰着7200万美国人和全球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低，通常需要每天服用一次或两次短效抗高血压药物。该项目探索了一种可能的高血压长期基因治疗方法，使用一种病毒，只需一次注射即可将扩张蛋白直接输送到动脉，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.