Intratubular Angiotensin II and AT1a Receptors in The Proximal Tubules: Roles in Hypertension and Kidney Injury

近曲小管中的管内血管紧张素 II 和 AT1a 受体：在高血压和肾损伤中的作用

• 批准号: 10398943
• 负责人: Jia L. Zhuo
• 金额: $ 44.01万
• 依托单位: TULANE UNIVERSITY OF LOUISIANA
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-05-18 至 2024-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10398943
• 关键词: Adult; Affect; Angiotensin II; Angiotensinogen; Animal Model; Antihypertensive Agents; Attenuated; Biological Assay; Blood Pressure; CCL2 gene; Cardiovascular Diseases; Cardiovascular system; Cells; Clip; Cre-LoxP; Data; Development; Down-Regulation; Drug Targeting; Elastin; Electrons; End stage renal failure; Fluorescein-5-isothiocyanate; Genes; Genetic Transcription; Genetically Modified Animals; Glomerular Filtration Rate; Glucose; Heart failure; Human; Hypertension; Image; Impairment; Infusion procedures; Injury to Kidney; Kidney; Kidney Failure; Knock-out; Knockout Mice; Knowledge; Left; Liver; Measurement; Measures; Microscopic; Mitochondria; Mitochondrial Proteins; Monitor; Natriuresis; Pathogenesis; Pathway interactions; Patients; Pharmacology; Play; Population; Profibrotic signal; Proteins; Proteomics; Proximal Kidney Tubules; Receptor Gene; Regulation; Renal Hypertension; Reperfusion Injury; Reverse Transcriptase Polymerase Chain Reaction; Role; Signal Transduction; Signaling Protein; Sirtuins; Small Intestines; Stroke; TLR4 gene; Telemetry; Testing; Time; Tissues; Tubular formation; United States; Western Blotting; adenoviral-mediated; antiporter; blood pressure elevation; blood pressure regulation; cardiovascular injury; cardiovascular risk factor; chemokine; clinically relevant; cytokine; extracellular; hypertensive; innovation; microscopic imaging; mitochondrial dysfunction; mouse model; multi-photon; novel; organ injury; overexpression; patient response; polypeptide; pressure; receptor; renal ischemia; response; symporter; therapeutic target; two-photon

Hypertension is the most important risk factor for cardiovascular diseases, stroke, and end-stage kidney failure. In the United States, nearly 46% of adults develop hypertension and will be treated with antihypertensive drugs in their lifetime. Only 50% of hypertensive patients are responsive to current antihypertensive drugs, whereas 1/3 of remaining hypertensive patients will develop cardiovascular, stroke and renal complications. The mechanisms responsible for the development of cardiovascular and kidney injury and the reasons for poor responses to current antihypertensive therapies remain incompletely understood. Thus, further studies are necessary in order to uncover new mechanisms, pathways, and therapeutic targets of uncontrolled hypertension and target organ injury. In preliminary studies, we used the state of the art SGLT2-Cre/LoxP approach to delete angiotensin II (ANG II) AT1a receptors, the Na+/H+ exchanger 3 (NHE3), or a key mitochondrial protein sirtuin 3 (SIRT3) selectively in the S1 and S2 segments of the proximal tubules in the kidney. We have evidence that proximal tubule-specific deletion of AT1a or NHE3 decreases basal blood pressure, augments the pressure natriuresis response, and attenuates ANG II-induced hypertension, and that proximal tubule-specific deletion of AT1a receptors significantly attenuated, whereas proximal tubule-specific deletion of SIRT3 significantly worsened renal ischemia and reperfusion (I/R) injury. These preliminary studies strongly suggest that intratubular ANG II and its AT1a receptors and SIRT3 in the proximal tubules play an important role in the development of hypertension and renal I/R injury. In this proposal, we will test the hypotheses that intratubular ANG II and AT1a receptors in the proximal tubules of the kidney are required for the development of ANG II-induced hypertension and renal I/R injury, and that deletion of AT1a receptors or angiotensinogen (AGT) selectively in the proximal tubules will attenuate ANG II-induced hypertension and renal I/R injury in two specific aims. Specific Aim 1 will test the hypothesis that intratubular ANG II and AT1a receptors in the proximal tubules play a key role in maintaining basal blood pressure homeostasis and the development of ANG II-induced hypertension, via the activation of the Na+/H+ antiporter (NHE3), Na+ and glucose cotransporter 2 (sglt2), and the regulation of the pressure natriuresis response. Specific Aim 2 will test the hypothesis that AT1a receptors in the proximal tubules play a key role in the pathogenesis of renal I/R injury, activated by intratubular and intracellular ANG II to upregulate Toll-Like receptor 4 (TLR-4), downregulate mitochondrial SIRT3 expression, and impair mitochondrial function in the proximal tubules. These hypotheses will be tested using highly innovative mouse models with global and proximal tubule-specific knockout of a) AT1a receptors; b) angiotensinogen; c) NHE3; d) SGLT2; e) TLR4; or f) SIRT3. ANG II-dependent hypertension and renal I/R injury will be induced by a) infusing a native ANG II; b) 2-kidney, 1-clip renal hypertension; c) a genetically encoded circulating Elastin-Like Polypeptide-ANG II (ELP-ANG II); or d) overexpressing a proximal tubule- specific, mitochondria-targeting intracellular ECFP/ANG II. Telemetry blood pressure, the pressure natriuresis response, noninvasive glomerular filtration rate, intravital two-photon imaging and XFe24 Extracellular Flux Analyzer to measure mitochondrial function, electron microscopic and immunohistochemical imaging, and Western blot analyses of proinflammatory, profibrotic and signaling proteins will be studied. The proposed studies are highly significant and clinically relevant, and the new knowledge will lead to a paradigm shift on understanding the pathogenesis of hypertension and renal I/R injury, and help develop proximal tubule-targeting drugs to treat poorly controlled hypertension and renal I/R injury.

高血压是心血管疾病、中风和终末期肾衰竭的最重要危险因素。在美国 美国近 46% 的成年人患有高血压，并将在一生中接受降压药物治疗。仅有的 50% 的高血压患者对当前的抗高血压药物有反应，而 1/3 的剩余高血压患者 患者会出现心血管、中风和肾脏并发症。负责发展的机制 心血管和肾脏损伤以及当前抗高血压治疗反应不佳的原因仍然存在 不完全理解。因此，有必要进行进一步的研究，以揭示新的机制、途径和方法。 不受控制的高血压和靶器官损伤的治疗目标。在初步研究中，我们使用了最先进的技术 SGLT2-Cre/LoxP 方法删除血管紧张素 II (ANG II) AT1a 受体、Na+/H+ 交换器 3 (NHE3) 或关键 线粒体蛋白 Sirtuin 3 (SIRT3) 选择性地存在于肾脏近端小管的 S1 和 S2 段中。我们 有证据表明，近端小管特异性删除 AT1a 或 NHE3 可降低基础血压，增强血压 压力尿钠反应，并减弱 ANG II 诱导的高血压，以及近端小管特异性缺失 AT1a 受体显着减弱，而近端小管特异性 SIRT3 缺失显着减弱 肾缺血和再灌注（I/R）损伤恶化。这些初步研究强烈表明管内 ANG II及其AT1a受体和近曲小管中的SIRT3在高血压和高血压的发生发展中发挥重要作用 肾缺血再灌注损伤。在本提案中，我们将测试肾小管内 ANG II 和 AT1a 受体的假设 肾近曲小管是 ANG II 诱导的高血压和肾 I/R 发展所必需的 损伤，并且选择性地删除近曲小管中的 AT1a 受体或血管紧张素原 (AGT) 将 减轻 ANG II 引起的高血压和肾 I/R 损伤有两个具体目标。具体目标 1 将测试 假设近曲小管中的管内 ANG II 和 AT1a 受体在维持基础血液中发挥关键作用 通过 Na+/H+ 逆向转运蛋白的激活，维持压力稳态和 ANG II 诱导的高血压的发生 (NHE3)、Na+ 和葡萄糖协同转运蛋白 2 (sglt2)，以及压力尿钠反应的调节。具体目标2 将检验近曲小管中的 AT1a 受体在肾 I/R 损伤的发病机制中发挥关键作用的假设， 由管内和细胞内 ANG II 激活，上调 Toll 样受体 4 (TLR-4)，下调 线粒体 SIRT3 表达，并损害近端小管中的线粒体功能。这些假设将 使用高度创新的小鼠模型进行测试，该模型具有 a) AT1a 的整体和近端小管特异性敲除 受体； b) 血管紧张素原； c) NHE3； d) SGLT2； e) TLR4；或 f) SIRT3。 ANG II 依赖性高血压和 肾 I/R 损伤将通过 a) 输注天然 ANG II 引起； b) 2-肾，1​​-夹肾性高血压； c) 遗传上 编码循环弹性蛋白样多肽-ANG II (ELP-ANG II)；或 d) 过度表达近端小管- 特异性、线粒体靶向细胞内 ECFP/ANG II。遥测血压、压力尿钠 反应、无创肾小球滤过率、活体双光子成像和 XFe24 细胞外通量分析仪 测量线粒体功能、电子显微镜和免疫组织化学成像以及蛋白质印迹分析 将研究促炎、促纤维化和信号蛋白的作用。拟议的研究高度 重要且具有临床相关性，新知识将导致理解的范式转变 高血压和肾缺血再灌注损伤的发病机制，并帮助开发近曲小管靶向药物来治疗不良疾病 控制高血压和肾缺血再灌注损伤。