Rho GTPases and Actin Cytoskeletal Function in Renal Ischemia

肾缺血中的 Rho GTP 酶和肌动蛋白细胞骨架功能

基本信息

批准号：
7990218
负责人：
Simon J. Atkinson
金额：
$ 6.42万
依托单位：
INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-12-18 至 2010-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7990218
关键词：
Actins Acute Kidney Failure Address Adenovirus Vector Affect Animal Model Animals Award Biochemical Biological Assay Blood flow Cell Culture Techniques Cell Polarity Cell Survival Cell physiology Cells Cellular Morphology Cellular Stress Clinical Complex Cytoskeletal Modeling Cytoskeleton Data Depressed mood Endothelial Cells Epithelial Cells Figs - dietary Fluorescence Microscopy Functional disorder Goals Guanosine Triphosphate Phosphohydrolases In Vitro Injury Ischemia Kidney Life Link Maintenance Measurement Measures Mediating Metabolic Morbidity - disease rate Outcome Pathway interactions Patient Care Patients Pharmaceutical Preparations Pharmacotherapy Phosphorylation Site Phosphotransferases Photons Play Proteins RNA Interference Recovery Regulation Relative (related person)Renal function Role Signal Pathway Signal Transduction Sirolimus Structure TSC1 gene TSC1/2 gene TSC2 gene Testing Translating Tubular formation adenylate kinase cell injury human FRAP1 protein in vivo in vivo Model injury and repair insight kidney cell monomer mortality mutant novel polymerization renal ischemia rho rho GTP-Binding Proteins sensor success therapy design

项目摘要

DESCRIPTION (provided by applicant): The persistence of ischemic acute renal failure as a major cause of morbidity and mortality in hospitalized patients and the relative lack of improvement in outcomes for these patients challenges us the better understand the cellular mechanisms underlying this injury. Disruption of the actin cytoskeletal organization that normally underpins the structure and function of proximal tubule epithelial cells is well-established as an early and critical aspect of injury, with direct consequences for renal function and cell survival. In the previous years of this award we have shown that Rho GTPases play critical roles that may mediate the cytoskeletal alterations observed with ischemia. Moreover, we showed that activities of RhoA, Rac1 and Cdc42 are sensitive to ATP depletion, but that the activity of each protein is differentially affected by depletion. We proposed that alterations in Rho GTPase activity and consequent cytoskeletal disruption are the result of signaling through the AMPK-TSC1/2 pathway resulting in inactivation of the type II (rapamycin insensitive) mTor complex 2, which has recently been shown to regulate the cytoskeleton through Rho GTPases or via novel mTOR independent pathways downstream of TSC1/2. We propose studies to test and elucidate our proposed mechanism using complementary studies in cell culture and in animal models of renal ischemia. We propose four specific aims to address our central hypothesis: 1) Investigate the activation of AMPK by ATP depletion in vitro and ischemia in vivo; 2) Investigate the role of TSC1/2 and Rheb GTPase signaling on Rho GTPase activity and cytoskeletal organization in vitro and in vivo; 3) Determine the effect of AMPK activation on the type II mTOR complex; 4) Determine the effect of altered AMPK, TSC1/2, Rheb and mTOR signaling on actin cytoskeletal organization and proximal tubule cell function in animal models of ischemic renal injury. These studies will determine the key mechanism linking energy depletion to cytoskeletal alterations, and afford an opportunity to identify targets for novel therapies. Narrative Ischemia (loss of blood flow) is a major cause of acute kidney failure. Currently there is a poor understanding of the way that kidney cells respond to ischemia, which makes it difficult to design therapies or drugs. The studies proposed will test a possible mechanism leading to cell injury that could be a target for drug therapy.

描述（由申请人提供）：缺血性急性肾衰竭是住院患者发病率和死亡率的主要原因，这些患者的结局相对缺乏改善，对我们挑战了我们更好地了解这种损伤的细胞机制。肌动蛋白细胞骨架组织的破坏通常是基于近端小管上皮细胞的结构和功能的破坏，这是损伤的早期和关键方面的完善，对肾功能和细胞存活的直接后果。在该奖项的前几年，我们表明Rho GTPases扮演着关键作用，可以介导缺血观察到的细胞骨架改变。此外，我们表明RhoA，Rac1和Cdc42的活性对ATP耗竭敏感，但是每种蛋白质的活性都会受到耗竭的影响。我们提出，Rho GTPase活性的变化和随之而来的细胞骨架破坏是通过AMPK-TSC1/2途径信号传导的结果，导致II型失活（Rapamycin不敏感）MTOR复合物2，最近已显示出通过Rho GTPase或Nemply pathowe downdowe downrowe downrowe downrowe downrowe downdrowe pathorey pathorey pathove consects condsce condsce condsce。我们建议使用细胞培养和肾脏缺血动物模型中的互补研究来测试和阐明我们提出的机制。我们提出了四个特定的目的，以解决我们的中心假设：1）在体内通过ATP耗竭研究AMPK的激活； 2）研究TSC1/2和RHEB GTPase信号在体外和体内的Rho GTPase活性和细胞骨架组织中的作用； 3）确定AMPK激活对II型MTOR复合物的影响； 4）确定改变AMPK，TSC1/2，RHEB和MTOR信号传导对肌动蛋白细胞骨架组织和近端小管细胞功能的影响。这些研究将确定将能量耗竭与细胞骨架改变联系起来的关键机制，并提供了鉴定新疗法靶标的机会。叙述缺血（血液流失）是急性肾衰竭的主要原因。目前，人们对肾细胞对缺血的反应方式的理解很差，这使得设计疗法或药物很难。提出的研究将测试导致细胞损伤的可能机制，这可能是药物治疗的靶标。