Role of Gq Signaling in Promoting Podocyte Injury in Diabetes Mellitus

Gq 信号传导在促进糖尿病足细胞损伤中的作用

基本信息

批准号：
8329659
负责人：
Robert Spurney
金额：
$ 34.15万
依托单位：
DUKE UNIVERSITY
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：
2011-09-09 至 2015-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8329659
关键词：
Americas Angiotensin II Receptor Animals Apoptosis Applications Grants Attenuated Calcium Cell Line Cell surface Cells Characteristics Clinical Complex Complication Coupled Developed Countries Diabetes Mellitus Diabetic Nephropathy Disease Disease Progression Doxycycline Economic Burden Economics End stage renal failure Endocrine system Endothelin Epidemic Etiology G-Protein-Coupled Receptors Genes Genetic Models Goals Healthcare Systems Human In Vitro Incidence Injury Inositol Phosphates Insulin-Dependent Diabetes Mellitus Kidney Kidney Diseases Mediator of activation protein Medicare Mus Natural regeneration Non-Insulin-Dependent Diabetes Mellitus PTGS2 gene Pathogenesis Patients Phospholipase Phosphoric Monoester Hydrolases Play Population Prostaglandins Role Second Messenger Systems Series Severities Signal Pathway Signal Transduction Stem cells System Technology Testing Thromboxanes Transgenic Mice United States base cost drug development glomerulosclerosis human MAPK14 protein in vivo inhibitor/antagonist novel therapeutics podocyte prevent promoter receptor regenerative research study rho GTP-Binding Proteins second messenger stress-activated protein kinase 1 therapeutic target treatment strategy type I and type II diabetes

项目摘要

DESCRIPTION (provided by applicant): Role of Gq signaling in promoting podocyte injury in diabetes mellitus: Diabetic nephropathy (DN) is the most common cause of end stage renal disease (ESRD) in developed countries. Accumulating evidence indicates that a reduced number of podocytes are a characteristic feature of both animals and humans with diabetic kidney disease. Because podocytes are terminally differentiated cells with little potential for proliferation, podocytes that are lost cannot be effectively replaced. In turn, sufficient loss of podocytes leads to instability of the tuft and glomerulosclerosis. While the etiology of podocyte loss in DN is complex, a large body of evidence suggests that cell surface G protein coupled receptors (GPCRs) play an important, injury promoting role in DN including receptors for angiotensin II (ANGII), thromboxanes (TP), prostaglandins (EP1) and endothelins (ETA). Indeed, these GPCRs are expressed by glomerular podocytes and several of these receptor systems have been shown to promote podocyte injury both in vitro and in vivo. A common feature of these injury-promoting GPCRs is activation of Gq a-subunits (Gq). Activation of Gq and its downstream effectors might, therefore, be a final common signaling pathway that synergizes with other signaling cascades to promote podocyte injury in DN. In this regard, we found that Gq dependent CN activation promotes podocyte apoptosis, in part, by induction of the CN responsive gene COX2. Based on these observations, we hypothesized that Gq-coupled signaling cascades are important mediators of podocyte injury in DN by promoting podocyte apoptosis. To investigate this hypothesis, 3 specific aims are proposed. In specific aim #1, we have created transgenic (TG) mice that express either a constitutively activate Gq a-subunit (GqQ>L) or a Gq inhibitor (Gqi) specifically in glomerular podocytes using an inducible promoter system. We will use GqQ>L or Gqi TG mice to determine if either activating or inhibiting Gq, respectively, specifically in glomerular podocytes modulates the severity of kidney disease in a genetic model of type 1 diabetes (Akita mice). In specific aim #2, we will determine the signaling cascades activated by Gq that promote podocyte apoptosis in an immortalized podocyte cell line as well as in vivo. Lastly, in specific aim #3, we will create mice lacking COX2 specifically in podocytes and then determine the effects of podocyte specific COX2 deletion on podocyte apoptosis and glomerular damage in Akita mice. These studies will test the utility of inhibiting Gq signaling as a potential treatment strategy in DN and the role of podocyte COX2 expression in disease pathogenesis. If successful, the results may suggest novel therapeutic strategies for treating diabetic kidney disease.

描述（由申请人提供）：Gq信号传导在促进糖尿病足细胞损伤中的作用：糖尿病肾病（DN）是发达国家终末期肾病（ESRD）的最常见原因。越来越多的证据表明，足细胞数量减少是患有糖尿病肾病的动物和人类的一个特征。由于足细胞是终末分化细胞，增殖潜力很小，因此丢失的足细胞无法有效替代。反过来，足细胞的足够损失会导致簇的不稳定和肾小球硬化。虽然 DN 足细胞丢失的病因很复杂，但大量证据表明细胞表面 G 蛋白偶联受体 (GPCR) 在 DN 中发挥着重要的促进损伤作用，包括血管紧张素 II (ANGII)、血栓素 (TP)、前列腺素 (EP1) 和内皮素 (ETA)。事实上，这些 GPCR 由肾小球足细胞表达，并且其中一些受体系统已被证明可在体外和体内促进足细胞损伤。这些促进损伤的 GPCR 的一个共同特征是 Gq a 亚基 (Gq) 的激活。因此，Gq 及其下游效应子的激活可能是最终的共同信号通路，与其他信号级联反应协同促进 DN 足细胞损伤。在这方面，我们发现 Gq 依赖性 CN 激活部分通过诱导 CN 响应基因 COX2 促进足细胞凋亡。基于这些观察，我们假设 Gq 偶联信号级联通过促进足细胞凋亡，是 DN 足细胞损伤的重要介质。为了研究这一假设，提出了 3 个具体目标。在具体目标#1中，我们创建了转基因（TG）小鼠，其使用诱导型启动子系统特异性地在肾小球足细胞中表达组成型激活的Gq a亚基（GqQ>L）或Gq抑制剂（Gqi）。我们将使用 GqQ>L 或 Gqi TG 小鼠来确定分别激活或抑制 Gq（特别是在肾小球足细胞中）是否会调节 1 型糖尿病遗传模型（秋田小鼠）中肾脏疾病的严重程度。在具体目标#2中，我们将确定 Gq 激活的信号级联，促进永生化足细胞细胞系以及体内的足细胞凋亡。最后，在具体目标#3中，我们将创建足细胞中特异性缺乏COX2的小鼠，然后确定足细胞特异性COX2缺失对秋田小鼠足细胞凋亡和肾小球损伤的影响。这些研究将测试抑制 Gq 信号传导作为 DN 潜在治疗策略的效用以及足细胞 COX2 表达在疾病发病机制中的作用。如果成功，结果可能会提出治疗糖尿病肾病的新治疗策略。