Novel downstream effectors of protein kinase G in hypertensive disease

摘要 高血压在美国是一个巨大的健康和社会经济负担，是导致 世界范围内的心血管发病率和死亡率。总体而言，三分之一的美国人患有高血压，近2%的人患有高血压 在65岁以上的美国人中，有三分之三的人。高血压会显著增加患心脏病的风险 心力衰竭(HF)，而降低血压则降低风险。众所周知，高血压是最重要的 射血分数(HFpEF)保留的心衰发生的共同危险因素 全身炎症和活性氧物种的激活降低了一氧化氮的生物利用度并损害了 蛋白激酶G(PKG)信号传导。慢性高血压的特点是收缩和舒张期受损。 心功能和病理重塑，以及过度的肾脏钠滞留和容量超负荷， 两者共同导致进展为HFpEF和预后不良。试图减少血液的治疗方法 HFpEF患者的压力大多未能产生积极的结果。许多患者患有高血压，即 抵抗常规治疗，而且由于大多数HFpEF患者是老年人，他们表现出老龄化 一氧化氮生物利用度和PKG信号的固有缺陷，使现有治疗效果较差。 虽然，已知PKG信号受损是高血压相关的心肾功能损害的中心。 特别是在老年人中，专门为增强PKG活性而设计的疗法并不成功。 我们的初步研究探索了一种操纵PKG水平以改善结果的替代方法 在高血压和HFpEF中，通过绕过复杂的信号级联而有利于直接靶向 PKG下游效应子。我们在调控序列中发现了一个可磷酸化的丝氨酸残基273(S273)。 蛋白MyBPC作为PKG的关键特异性下游靶点，在各种压力模型中上调 超负荷诱导的高血压，但在HFpEF模型中下调。这些观察结果奠定了 为我们的一般假设奠定了基础，即增加慢性HTN的S273磷酸化水平可以预防 进展到HFpEF。在目标1中，我们将确定S273的PKG特异性的体外分子机制 在目标2中，我们将利用高血压和HFpEF的实验模型和新的转基因技术 动物模型，以确定PKG水平改变和衰老的体内功能后果，以及Aim 3 我们将利用体内心脏选择性AAV9病毒基因传递拟磷脂S273来预防或逆转 老年小鼠和消融PKG小鼠的HFpEF表型。成功地完成了这些机械 研究有望将S273确定为治疗高血压引起的HFpEF的新治疗策略， 一种没有有效治疗方法的毁灭性疾病。

Abstract Hypertension is an enormous health and socio-economic burden in the United States and is a leading cause of cardiovascular morbidity and mortality worldwide. Overall, 1 in 3 of Americans have hypertension, and nearly 2 in 3 of Americans over the age of 65 years. Hypertension significantly increases the risk of developing heart failure (HF), whereas reducing blood pressure decreases the risk. It is known that hypertension is the most common risk factor in the development of HF with preserved ejection fraction (HFpEF) by a mechanism where systemic inflammation and activation of reactive oxygen species reduces nitric oxide bioavailability and impairs Protein kinase G (PKG) signaling. Chronic hypertension is characterized by impaired systolic and diastolic cardiac function and pathological remodeling, and excessive renal sodium retention and volume overload, which together contribute to progression to HFpEF and a poor prognosis. Therapies attempting to reduce blood pressure in HFpEF patients have mostly failed to yield positive results. Many patients have hypertension that is resistant to conventional therapy, and because the majority of HFpEF patients are elderly, they display aging inherent deficits in nitric oxide bioavailability and PKG signaling that make available therapies less effective. Although, it is known that impaired PKG signaling is central to the cardio-renal deficits related to hypertension especially in older individuals, therapies specifically designed to enhance PKG activity have not been successful. Our preliminary studies have explored an alternative approach to manipulating PKG levels to improve outcomes in hypertension and HFpEF by bypassing complex signaling cascades in favor of directly targeting the downstream effectors of PKG. We have identified a phosphorylatable serine residue 273 (S273) in the regulatory protein MyBPC as a critical specific downstream target of PKG that is upregulated in various models of pressure overload-induced hypertension, but is downregulated in models of HFpEF. These observations lay the foundation for our general hypothesis that increasing S273 phosphorylation levels in chronic Htn prevents progression to HFpEF. In Aim 1 we will define the PKG-specific in vitro molecular mechanisms of S273 phosphorylation, in Aim 2 we will utilize experimental models of hypertension and HFpEF and novel transgenic animal models to determine the in vivo functional consequences of altered PKG levels and aging, and in Aim 3 we will utilize in vivo cardioselective AAV9 viral gene delivery of phosphomimetic S273 to prevent or reverse the HFpEF phenotype in aged mice and in mice with ablated PKG. Successful completion of these mechanistic studies have the promise to identify S273 as a novel therapeutic strategy to treat hypertension-induced HFpEF, a devastating disease with no effective treatments.