Regulation of Ras Signaling by Rlf In Hypertrophy

Rlf 在肥大中对 Ras 信号传导的调节

基本信息

批准号：
7324811
负责人：
Steven Post
金额：
$ 15.67万
依托单位：
UNIVERSITY OF KENTUCKY
依托单位国家：
美国
项目类别：
财政年份：
2003
资助国家：
美国
起止时间：
2003-12-01 至 2009-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7324811
关键词：
1-Phosphatidylinositol 3-Kinase Age Americas Antisense Oligonucleotides Atrial Natriuretic Factor Binding Proteins Cardiac Cells Cellular Stress Chronic Congestive Heart Failure Depressed mood Development Diagnosis Exhibits Experimental Models Family Fibrosis Functional disorder GTP-Binding Proteins Genetic Guanine Guanine Nucleotide Exchange Factors HRAS gene Heart Heart Diseases Heart Hypertrophy Heart failure Human Hypertrophic Cardiomyopathy Hypertrophy Infusion procedures Isoproterenol JNK-activating protein kinase Lead MAPK8 gene MEKs Mediating Modeling Mus Muscle Cells Myocardial Myocardium Myosin Heavy Chains N-terminal Neonatal Nucleotides Pathogenesis Pathway interactions Phenotype Phosphoinositide-3-Kinase, Catalytic, Gamma Polypeptide Phosphotransferases Protein Overexpression Rattus Regulation Research Personnel Risk Role Severities Signal Pathway Signal Transduction Sorbitol Stimulus Stress Survival Rate Testing Transgenic Mice Transgenic Organisms Ventricular Week Work cDNA Library in vivo interstitial member mouse model novel novel therapeutics outcome forecast pressure prevent programs promoter response

项目摘要

DESCRIPTION (provided by applicant): Important recent advances derived from experimental models of cardiac hypertrophy suggest that distinct signaling pathways regulate compensated hypertrophy and decompensated heart failure. Ras is a small GTP binding protein that signals through multiple effectors, including the Raf-MEK-ERK pathway, PI3 kinase (PI3K), guanine exchange factors for Ral (RalGEFs) and cJun N-terminal kinase (JNK). In transgenic mice, V12Ras-mediated hypertrophy is associated with JNK activation and depressed cardiac function. However, certain Ras-dependent signaling cascades, including ERK and PI3K, activate compensatory hypertrophic responses that preserve contractile activity. To identify novel Ras effectors we screened a human heart cDNA library using Ras as bait and isolated Ral guanine nucleotide exchange factor-like factor (RIf). To examine the functional consequence of the Ras-RIf interaction, we expressed V12Ras in concert with RIf in neonatal ventricular rat myocytes (NRVM). Expression of RIf suppressed V12Ras-induced JNK activity and ANF expression but not other Ras effectors. RIf also inhibited sorbitol-induced JNK activation indicating that RIf expression negatively regulates JNK activation in response to multiple stimuli. These results demonstrate that RIf suppresses an effector pathway suggested to mediate depressed function of myocardial cells. We will test the hypothesis that RIf negatively regulates JNK activation and that function inhibits the development of hypertrophic cardiomyopathy in vivo. The signaling pathways that couple Ras to JNK activation are not known but may involve MEKK1 (MAPWERK kinase kinase 1), a Ras binding protein that preferentially activates JNK. In aim #1, we will define the role of MEKK1-JKK-JNK in RIf-mediated inhibition of V12Ras- and stress- signaling. In aims #2 and #3, the pathophysiological implications of RIf function will be investigated in transgenic mice that overexpress RIf. We will test the potential protective role of RIf on the pathogenesis of cardiac hypertrophy in response to pressure overload, isoproterenol infusion and V12Ras overexpression and investigate the signaling cascades involved. Elucidation of the mechanisms by which RIf regulates hypertrophic signaling pathways may lead the development of novel therapeutic approaches to prevent cardiac dysfunction.

描述（由申请人提供）：从心脏肥大的实验模型得出的重要进展表明，不同的信号通路调节补偿肥大和代偿性心力衰竭。 RAS是一种小的GTP结合蛋白，它通过多个效应子发出信号，包括RAF-MEK-ERK途径，PI3激酶（PI3K），RAL（RALGEFS）的鸟嘌呤交换因子和CJUN N末端激酶（JNK）。在转基因小鼠中，V12RAS介导的肥大与JNK激活和抑郁心脏功能有关。但是，包括ERK和PI3K在内的某些RAS依赖性信号级联激活了保留收缩活性的补偿性肥厚反应。为了识别新型RAS效应子，我们使用RAS作为诱饵和分离的Ral鸟嘌呤核苷酸交换因子（RIF）筛选了人心脏cDNA文库。为了检查RAS-RIF相互作用的功能后果，我们在新生儿心室大鼠肌细胞（NRVM）中与RIF共同表示V12RA。 RIF的表达抑制了V12RAS诱导的JNK活性和ANF表达，但没有其他RAS效应子。 RIF还抑制了山梨糖醇诱导的JNK激活，表明RIF表达对多种刺激的响应对JNK激活进行负调节。这些结果表明，RIF抑制了建议介导心肌细胞抑郁功能的效应途径。我们将检验以下假设，即RIF负调节JNK激活，并且该假设的功能抑制了体内肥厚性心肌病的发展。尚不清楚将对ras与JNK激活的RAS相对的信号传导途径，但可能涉及MEKK1（MAPWERK激酶激酶1），这是一种优先激活JNK的Ras结合蛋白。在AIM＃1中，我们将定义MEKK1-JKK-JNK在RIF介导的V12RAS和应力信号传导抑制中的作用。在AIMS＃2和＃3中，将在过表达RIF的转基因小鼠中研究RIF功能的病理生理意义。我们将测试RIF在压力过载，异丙肾上腺素输注和V12RAS过表达的响应中，RIF对心脏肥大的发病机理的潜在保护作用，并研究所涉及的信号传导级联。阐明RIF调节肥厚信号通路的机制可能会导致新型治疗方法的发展以防止心脏功能障碍。