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: 10627786
• 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 2025-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10627786
• 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; Inflammatory; 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; Play; Population; 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; absorption; adenoviral mediated; antiporter; blood pressure elevation; blood pressure regulation; cardiovascular injury; cardiovascular risk factor; chemokine; clinically relevant; cytokine; extracellular; hypertensive; innovation; ischemic injury; microscopic imaging; mitochondrial dysfunction; mouse model; multi-photon; novel; organ injury; overexpression; patient response; pharmacologic; 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，中风和末期肾衰竭的最重要危险因素。在曼联 各州，近46％的成年人患有高血压，并将在其一生中接受降压药治疗。仅有的 50％的高血压患者对当前的降压药有反应，而剩余的高血压为1/3 患者会发展心血管，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对当前降压治疗的反应不佳的原因仍然存在 不完全理解。因此，为了发现新的机制，途径和 不受控制的高血压和靶器官损伤的治疗靶标。在初步研究中，我们使用了最先进的状态 删除血管紧张素II（ANG II）AT1A受体，Na+/H+交换器3（NHE3）或键的SGLT2-CRE/LOXP方法 线粒体蛋白SIRTUIN 3（SIRT3）在肾脏近端小管的S1和S2段中有选择地。我们 有证据表明，AT1A或NHE3的近端小管特异性缺失可降低基础血压，增强 压力纳地硫酸盐反应，并减轻ANG II诱导的高血压，并近端小管特异性缺失 AT1A受体的大量减弱，而SIRT3的近端小管特异性缺失显着减弱 恶化的肾脏缺血和再灌注（I/R）受伤。这些初步研究强烈表明，间管内ANG II及其近端小管中的AT1A受体和SIRT3在高血压发展中起重要作用 肾脏I/R受伤。在此提案中，我们将测试在本内ANG II和AT1A受体中的假设 肾脏的近端小管是ANG II诱导的高血压和肾脏I/R的发展所必需的 损伤，在近端小管中选择性地缺失AT1A受体或血管紧张素原（AGT） 在两个特定目标中减弱了ANG II诱导的高血压和肾脏I/R损伤。特定目标1将测试 假设近端小管中的囊内ANG II和AT1A受体在维持基础血液中起关键作用 压力稳态和ANG II诱导的高血压的发展，通过Na+/H+抗肌动物的激活 （NHE3），Na+和葡萄糖共转运蛋白2（SGLT2），以及压力纳地尿反应的调节。具体目标2 将检验以下假设：近端小管中的AT1A受体在肾脏I/R损伤的发病机理中起关键作用， 被囊内和细胞内ANG II激活，以上调类似的受体4（TLR-4），下调 线粒体SIRT3表达，并在近端小管中损害线粒体功能。这些假设会 使用具有全球和近端小管特异性敲除A）AT1A的高度创新的鼠标模型进行测试 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 肾脏I/R损伤将由A）注入本地ANG II； b）2-kidney，1张肾脏高压； c）遗传学 编码的循环弹性弹性蛋白样多肽-ANG II（ELP-ANG II）；或d）过表达近端小管 特定的，线粒体靶向细胞内ECFP/ANG II。遥测血压，压力纳地液 反应，无创肾小球滤过速率，浸润性的两光子成像和XFE24细胞外通量分析仪对 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，纤维化和信号传导蛋白。提出的研究高度 重要且在临床上相关，新知识将导致理解的范式转变 高血压和肾脏I/R损伤的发病机理，并有助于开发近端小管靶向药物以治疗不良 控制高血压和肾脏I/R损伤。