SGLT2 Mediates Glucose-Induced Angiotensinogen Synthesis in Proximal Tubule Cells

SGLT2 介导近端小管细胞中葡萄糖诱导的血管紧张素原合成

• 批准号: 8983617
• 负责人: Michael Winthers Cypress
• 金额: $ 4.31万
• 依托单位: TULANE UNIVERSITY OF LOUISIANA
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-01-04 至 2017-01-03
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8983617
• 关键词: Address; Angiotensin II; Angiotensinogen; Antioxidants; Attenuated; Blood Glucose; Blood Pressure; Cell Culture Techniques; Cell Line; Cell membrane; Cells; Chronic; Development; Diabetes Mellitus; Diabetic Nephropathy; Experimental Designs; Generations; Glucose; Hyperglycemia; Hypertension; Injury; Insulin-Dependent Diabetes Mellitus; Kidney; Kidney Failure; Knockout Mice; Laboratories; Measures; Mediating; Messenger RNA; Mitochondria; Molecular; Mus; NADPH Oxidase; Non-Insulin-Dependent Diabetes Mellitus; Oxidative Stress; Oxygen Consumption; Pathway interactions; Patients; Pharmacologic Substance; Plasma; Prevention; Process; Production; Proteins; Proximal Kidney Tubules; Reactive Oxygen Species; Receptor Activation; Receptor, Angiotensin, Type 1; Regulation; Renin-Angiotensin System; Reporting; Research; Respiration; Role; Sodium; Source; Staging; Testing; Tubular formation; United States; Up-Regulation; Urine; extracellular; glucose metabolism; human CYBA protein; improved; inhibitor/antagonist; insight; prevent; public health relevance; receptor; response; symporter; tempol; treatment strategy

 DESCRIPTION (provided by applicant): The intra-renal renin-angiotensin system (RAS) has been implicated in the development of hypertension and the progression of kidney injury that results from diabetes mellitus. RAS blockade is an effective strategy in preventing diabetic nephropathy and hypertension during diabetes. The production of angiotensinogen (AGT) is upregulated in the renal proximal tubular cells under high glucose conditions. This process is partially mediated by the formation of reactive oxygen species (ROS) as a result of glucose metabolism and mitochondrial respiration. AGT forms angiotensin II (Ang II) which causes oxidative stress by activating the Ang II Type 1 Receptor (AT1R). AT1R activation is also a major source of ROS generation in proximal tubular cells. The overall aim of this proposal is to elucidate the mechanisms underlying the up-regulation of AGT in the proximal tubule during diabetes and chronic hyperglycemia. The sodium-glucose cotransporter 2 (SGLT2) is the primary mechanism responsible for reabsorbing filtered glucose in the kidney. It is not known if SGLT2- mediated glucose reabsorption is responsible for the increased intratubular AGT expression reported during diabetes. Therefore, our overall hypothesis is that the increase in AGT expression in proximal tubular cells under high glucose conditions is mediated by increased glucose entry via SGLT2 which synergizes with the effects of AT1R activation. This will provide insight into the molecular mechanisms that occur in the kidney in the early stages of diabetes. To test this hypothesis, we will establish an increase in ROS accumulation and AGT expression in proximal tubular cells cultured in high glucose conditions and that this upregulation is dependent on glucose entry via SGLT2. We will demonstrate that glucose entry and mitochondrial respiration are increased by Ang II through AT1R activation. In addition, we will show that AT1R activation synergizes with the effects of high glucose to augment AGT expression. The experimental design will utilize immortalized proximal tubular cell lines derived from the wild type and AT1R knockout mice. Canagliflozin, a highly selective pharmaceutical blocker of SGLT2, will be used to demonstrate the role of SGLT2 on the production of AGT during high glucose conditions and address the overall hypothesis.

 描述(由申请人提供)：肾内肾素-血管紧张素系统(RAS)与高血压的发展和糖尿病引起的肾脏损伤的进展有关。RAS阻断是预防糖尿病肾病和糖尿病合并高血压的有效策略。在高糖条件下，肾小管上皮细胞血管紧张素原(AGT)的产生被上调。这一过程部分是由葡萄糖代谢和线粒体呼吸所导致的活性氧物种(ROS)的形成所介导的。血管紧张素转换酶形成血管紧张素II(Ang II)，通过激活Ang II 1型受体(AT1R)引起氧化应激。AT1R的激活也是近端肾小管细胞产生ROS的主要来源。这项建议的总体目的是阐明糖尿病和慢性高血糖时近端小管AGT上调的潜在机制。钠-葡萄糖共转运体2(SGLT2)是肾脏重新吸收过滤葡萄糖的主要机制。目前尚不清楚SGLT2介导的葡萄糖重吸收是否是糖尿病期间肾小管内AGT表达增加的原因。因此，我们的总体假设是，高糖条件下近端肾小管细胞AGT表达的增加是通过SGLT2增加葡萄糖进入而介导的，这与AT1R激活的效应是协同的。这将提供对糖尿病早期肾脏中发生的分子机制的洞察。为了验证这一假设，我们将建立在高糖条件下培养的近端肾小管细胞ROS积累和AGT表达增加的情况，并且这种上调依赖于通过SGLT2的葡萄糖进入。我们将证明血管紧张素转换酶II通过激活AT1R来增加葡萄糖进入和线粒体呼吸。此外，我们将证明AT1R的激活与高糖的作用协同作用，以增强AGT的表达。实验设计将利用来自野生型和AT1R基因敲除小鼠的永生化近端肾小管细胞系。Canagliflzin是一种高度选择性的SGLT2药物阻滞剂，将用于证明SGLT2在高糖条件下对AGT产生的作用，并解决总体假说。