Receptor Na/K-ATPase Antagonists As Novel Therapeutics For Renal/Cardiac Diseases

受体 Na/K-ATP 酶拮抗剂作为肾病/心脏病的新型疗法

基本信息

批准号：
8159937
负责人：
JOSEPH Isaac SHAPIRO
金额：
$ 56.69万
依托单位：
UNIVERSITY OF TOLEDO HEALTH SCI CAMPUS
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-08-18 至 2015-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8159937
关键词：
1-Phosphatidylinositol 3-Kinase Abbreviations Address Affinity Agonist Angiotensin II Animals Antibodies Attenuated Binding Biology Blood Pressure Cardiac Cardiac Glycosides Cardiomyopathies Cell Culture Techniques Cells Chronic Chronic Kidney Failure Clinical Complex Congestive Heart Failure Cultured Cells Diet Dominant-Negative Mutation Effectiveness Endocytosis Fibrosis Fluorescence Functional disorder Generations Goals Heart Heart Diseases Heart Hypertrophy ITPR1 gene In Vitro Inositol Ion Pumps Kidney Kidney Diseases Kidney Failure Lesion Ligands Mediating Modeling Mus Muscle Cells Na(+)-K(+)-Exchanging ATPase Nephrectomy Organ Ouabain Pathogenesis Pathway interactions Peptides Play Protein Kinase Protein Kinase C Proteins Rattus Reactive Oxygen Species Receptor Activation Regulation Research Resistance Risk Factors Role Series Signal Transduction Sodium Chloride Solid Steroid Receptors Stimulus Stress Testing Therapeutic Transgenic Mice Transgenic Organisms base in vitro activity in vivo marinobufagenin novel novel therapeutics prevent receptor receptor function small molecule tool tripolyphosphate

项目摘要

DESCRIPTION (provided by applicant): We find that the Na/K-ATPase has an ion pumping-independent receptor function. Specifically, it associates with Src to form a receptor complex. Binding of cardiotonic steroids to this receptor complex activates Src, which, in turn, initiates a series of signaling cascades including the generation of reactive oxygen species (ROS) and the activation of PI3K/Akt pathways in renal and cardiac cells. Moreover, we demonstrate a significant increase in circulating CTS in rat model of uremic cardiomyopathy induced by 5/6 nephrectomy (PNx). Neutralization of this increase in CTS reduced ROS stress and diminished cardiomyopathy characterized by myocyte hypertrophy and cardiac fibrosis. Thus, we hypothesize that chronic stimulation of this newly appreciated receptor mechanism by elevated CTS may be the cause of the cardiac remodeling observed in uremic rats. Conversely, inhibition of the receptor function could attenuate the pathological changes in the target organs under this and other clinical conditions where CTS are elevated. Recently, we have developed several new tools that allow us to further test these hypotheses in vivo. First, we find that the N-terminus (NT) of a1 subunit acts as a dominant negative mutant capable of inhibiting CTS-induced signal transduction. Second, NT transgenic mice, in contrast to their wild-type littermates, are resistant to high salt diet-induced structural damages in the heart and in the kidney. Third, we have developed a peptide antagonist of receptor Na/K-ATPase/Src complex and demonstrated its effectiveness in vitro and in vivo. Finally, we have identified a novel class of small molecule antagonists that prevent ouabain from activating protein kinases in cell cultures. Therefore, we propose the following three specific aims. Aim 1 will test whether that chronic stimulation of the ion pumping-independent receptor function of Na/K-ATPase by CTS could result in pathological changes in the heart and the kidney. Aim 2 will address whether inhibition of Na/K-ATPase- mediated signal transduction by NT or pNaKtide attenuates high salt- and PNx-induced remodeling. In aim 3 we will further characterize the in vitro and in vivo activity of MB5 as a new class of CTS antagonists and test the in vivo effectiveness of MB5 in conferring resistance to CTS-induced organ damage. The completion of these three specific aims would significantly advance our understanding of endogenous CTS and Na/K- ATPase-mediated signal transduction in animal pathophysiology. Moreover, it would provide proof of the concept that antagonists of the receptor Na/K-ATPase can actually reduce renal and cardiac damages. PUBLIC HEALTH RELEVANCE: We have discovered a new receptor mechanism that plays an important role in the pathogenesis of renal and cardiac diseases. The proposed research will further advance our understanding of this receptor mechanism and explore the possibility of using the newly discovered receptor antagonists to prevent renal insufficiency and high salt diet-induced cardiac lesions.

描述（由申请人提供）：我们发现Na/k-ATPase具有与离子泵浦无关的受体函数。具体而言，它与SRC合并以形成受体复合物。心脏元素类固醇与该受体复合物的结合激活了SRC，这反过来又引发了一系列信号级联反应，包括活性氧（ROS）的产生以及肾细胞中PI3K/AKT途径的激活。此外，我们证明了由5/6肾切除术（PNX）诱导的尿毒症心肌病模型的循环CTS显着增加。 CTS增加的中和减少了ROS应激，并以肌细胞肥大和心脏纤维化为特征的心肌病降低。因此，我们假设通过升高CTS对这种新欣赏的受体机制的慢性刺激可能是尿毒症大鼠中心脏重塑的原因。相反，对受体功能的抑制可能会削弱在CT升高CTS和其他临床条件下目标器官的病理变化。最近，我们开发了几种新工具，使我们能够在体内进一步检验这些假设。首先，我们发现A1亚基的N端（NT）充当能够抑制CTS诱导的信号转导的显性负突变体。其次，与野生型同窝仔相比，NT转基因小鼠对高盐饮食引起的心脏和肾脏的结构性损害具有抵抗力。第三，我们开发了一种受体Na/K-ATPase/SRC复合物的肽拮抗剂，并在体外和体内证明了其有效性。最后，我们已经确定了一类新型的小分子拮抗剂，这些拮抗剂可防止瓦巴因激活细胞培养物中的蛋白激酶。因此，我们提出以下三个特定目标。 AIM 1将测试CTS对Na/k-ATPase的离子泵浦非依赖受体功能的慢性刺激是否会导致心脏和肾脏的病理变化。 AIM 2将解决NT或PNAKTIDE对Na/K-ATPase介导的信号转导的抑制是否会减弱高盐和PNX诱导的重塑。在AIM 3中，我们将进一步将MB5的体外和体内活性描述为新类CTS拮抗剂，并测试MB5在赋予CTS诱导的器官损伤的耐药性方面的体内有效性。这三个特定目标的完成将显着提高我们对内源性CT和Na/k- ATPase介导的信号转导的理解。此外，它将提供证明受体Na/K-ATPase的拮抗剂实际上可以减少肾脏和心脏损害的概念。公共卫生相关性：我们发现了一种新的受体机制，该机制在肾脏和心脏疾病的发病机理中起着重要作用。拟议的研究将进一步提高我们对这种受体机制的理解，并探索使用新发现的受体拮抗剂来防止肾脏不足和高盐饮食诱导的心脏病变的可能性。