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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：
8321448
负责人：
JOSEPH Isaac SHAPIRO
金额：
$ 56.44万
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/8321448
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.

描述（由申请人提供）：我们发现Na/ k - atp酶具有不依赖离子泵的受体功能。具体来说，它与Src结合形成受体复合物。强心剂与该受体复合物结合激活Src，进而启动一系列信号级联反应，包括活性氧（ROS）的产生和肾和心脏细胞中PI3K/Akt通路的激活。此外，我们发现5/6肾切除术（PNx）引起的尿毒症心肌病大鼠模型中循环CTS显著增加。中和CTS增加可减少ROS应激，减轻以心肌细胞肥大和心脏纤维化为特征的心肌病。因此，我们假设CTS升高对这种新发现的受体机制的慢性刺激可能是尿毒症大鼠心脏重构的原因。相反，在CTS升高的情况下，抑制受体功能可以减轻靶器官的病理变化。最近，我们开发了几个新工具，使我们能够在体内进一步测试这些假设。首先，我们发现a1亚基的n端（NT）作为一个显性负突变体，能够抑制cts诱导的信号转导。其次，与野生型小鼠相比，NT转基因小鼠对高盐饮食引起的心脏和肾脏结构损伤具有抵抗力。第三，我们已经开发了受体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的小分子拮抗剂，可以防止乌阿巴因激活细胞培养中的蛋白激酶。为此，我们提出以下三个具体目标。目的1将测试CTS对Na/ k - atp酶的离子泵非依赖性受体功能的慢性刺激是否会导致心脏和肾脏的病理改变。目的2将探讨NT或pNaKtide对Na/ k - atp酶介导的信号转导的抑制是否会减弱高盐和pnx诱导的重构。在目标3中，我们将进一步表征MB5作为一类新的CTS拮抗剂的体外和体内活性，并测试MB5在体内对CTS诱导的器官损伤产生抗性的有效性。这三个特定目标的完成将显著推进我们对内源性CTS和Na/K- atp酶介导的动物病理生理信号转导的理解。此外，它将证明受体Na/ k - atp酶拮抗剂实际上可以减少肾脏和心脏损伤的概念。