NADPH oxidases-derived ROS downregulate TRPC6 in mesangial cells in diabetes

NADPH 氧化酶衍生的 ROS 下调糖尿病肾小球膜细胞中的 TRPC6

• 批准号: 8069863
• 负责人: RONG MA
• 金额: $ 28.04万
• 依托单位: UNIVERSITY OF NORTH TEXAS HLTH SCI CTR
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-05-15 至 2014-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8069863
• 关键词: Address; Agonist; Animal Model; Applications Grants; Area; Blood Vessels; Cell Culture Techniques; Cell surface; Characteristics; Clinical Treatment; Complications of Diabetes Mellitus; Development; Diabetes Mellitus; Diabetic Nephropathy; Down-Regulation; Drug Design; Enzymes; Extracellular Matrix; Family; Focal Segmental Glomerulosclerosis; Generations; Genes; Genetic Transcription; Glomerular Capillary; Glomerular Filtration Rate; Glomerular Mesangial Cell; Glucose; Homologous Gene; Human; Hyperglycemia; Hypertrophy; Impairment; In Vitro; Kidney; Kidney Diseases; Link; Measures; Mediating; Messenger RNA; Molecular; NADP; NADPH Oxidase; Oxidative Stress; Pathway interactions; Phagocytes; Phenotype; Physiological; Play; Property; Protein Isoforms; Proteins; Rattus; Reactive Oxygen Species; Regulation; Reporting; Rest; Role; Series; Signal Pathway; Signal Transduction; Smooth Muscle Myocytes; Source; Staging; Streptozocin; Surface; System; Testing; Vascular Smooth Muscle; Vasoconstrictor Agents; Work; arteriole; cell type; diabetic; diabetic rat; hemodynamics; in vivo; interest; kidney cortex; mRNA Expression; member; mesangial cell; novel; podocyte; protein expression; public health relevance; receptor; response

DESCRIPTION (provided by applicant): At the early stage of diabetes, the GFR becomes supernormal. This early hemodynamic phenotype provokes the subsequent demise of a diabetic kidney. The diabetic hyperfiltration is derived from a combined decreased responsiveness of both the renal afferent arterioles and the MCs to vasoconstrictors. Reduced Ca2+ influx is a critical contributing factor to the hypocontractility of MCs in diabetes. However, the underlying mechanism(s) are still poorly understood. Furthermore, emerging evidence implicates NADPH oxidases-, particularly Nox4-derived ROS in the development of diabetic nephropathy. However, the underlying mechanism and downstream signaling pathway are at a large extent unknown. This proposal seeks to test the hypothesis that TRPC6 protein, a newly found Ca2+ permeable channel protein, contributes to the contractile function of MCs and downregulation of the protein in MCs by NADPH oxidases-mediated ROS results in diabetic hyperfiltration. Three specific aims will be tested. (1) Determine whether TRPC6 regulates contractile function and Ca2+ signaling of glomerular MCs in in vitro, ex vivo, and in vivo systems. (2) Explore the postulate that ROS mediate downregulation of TRPC6 protein expression in glomerular MCs by diabetes in an in vitro (cultured MCs) and in vivo animal model. (3) Determine the source of ROS, focusing on NADPH oxidases, and the molecules downstream ROS, focusing on NF-ko, in the signaling pathway of TRPC6 downregulation by diabetes. The information obtained from this novel study will advance our current understanding of the molecular mechanism for the development of diabetic nephropathy, and therefore provides a rationale for drug design and clinical treatment of diabetes by intervening in the proposed pathway. In addition, TRPC6 has been found to play an important role in a variety of cell types. However, regulation of TRPC6 channel, particularly at gene transcriptional level, is unknown currently. The proposed studies will tackle this important issue by investigating if ROS repress TRPC6 gene transcription through the NF-ko mechanism. Thus, this project is of interest to both ROS and TRPC6 fields. PUBLIC HEALTH RELEVANCE: The proposed study is to test the hypothesis that a decrease in expression level of TRPC6 channel protein leads to the diabetic hyperfiltration at early stage of Diabetes. We further propose that a reactive oxygen species-involved signaling pathway mediates the decrease in TRPC6 protein in diabetes.

描述（申请人提供）： 在糖尿病早期，GFR 变得超正常。这种早期的血流动力学表型会引发糖尿病肾病随后的死亡。糖尿病性高滤过源自肾传入小动脉和 MC 对血管收缩剂的综合反应性降低。 Ca2+ 流入减少是糖尿病中 MC 收缩力低下的一个关键因素。然而，潜在的机制仍然知之甚少。此外，新出现的证据表明 NADPH 氧化酶，特别是 Nox4 衍生的 ROS 与糖尿病肾病的发展有关。然而，其潜在机制和下游信号通路在很大程度上尚不清楚。该提案旨在检验这样的假设：TRPC6 蛋白（一种新发现的 Ca2+ 通透性通道蛋白）有助于 MC 的收缩功能，并且 NADPH 氧化酶介导的 ROS 下调 MC 中的蛋白质，导致糖尿病超滤。将测试三个具体目标。 (1) 确定 TRPC6 是否在体外、离体和体内系统中调节肾小球 MC 的收缩功能和 Ca2+ 信号传导。 (2)在体外（培养的MC）和体内动物模型中探索ROS介导糖尿病导致的肾小球MC中TRPC6蛋白表达下调的假设。 (3)确定糖尿病下调TRPC6信号通路中ROS的来源，重点关注NADPH氧化酶，以及ROS下游分子，重点关注NF-ko。从这项新研究中获得的信息将增进我们目前对糖尿病肾病发展的分子机制的理解，从而为药物设计和通过干预所提出的途径来临床治疗糖尿病提供依据。此外，TRPC6被发现在多种细胞类型中发挥着重要作用。然而，TRPC6通道的调控，特别是在基因转录水平上的调控，目前尚不清楚。拟议的研究将通过调查 ROS 是否通过 NF-ko 机制抑制 TRPC6 基因转录来解决这一重要问题。因此，该项目对 ROS 和 TRPC6 领域都很感兴趣。 公共健康相关性：本研究旨在检验以下假设：TRPC6 通道蛋白表达水平降低会导致糖尿病早期糖尿病性高滤过。我们进一步提出活性氧参与的信号通路介导糖尿病中 TRPC6 蛋白的减少。