Novel Roles of Mitochondrial Angiotensin II in The Proximal Tubule of The Kidney

线粒体血管紧张素 II 在肾近端小管中的新作用

• 批准号: 9765283
• 负责人: Jia L. Zhuo
• 金额: $ 20.81万
• 依托单位: UNIVERSITY OF MISSISSIPPI MED CTR
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-03-01 至 2020-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9765283
• 关键词: AGTR2 gene; Adult; Agonist; Angiotensin II; Antihypertensive Agents; Attenuated; Biological Markers; Blood Pressure; CCL2 gene; Cardiovascular Diseases; Cardiovascular system; Cell Nucleus; Cell surface; Cells; Chimeric Proteins; Clinical Trials; Congestive Heart Failure; Cyclic GMP; Drug Targeting; Electrons; Endosomes; Female; Funding; Genetic Transcription; Genus Hippocampus; Glycolysis; Grant; Hypertension; Impairment; In Vitro; Kidney; Kidney Diseases; Kidney Failure; Knockout Mice; LDL-Receptor Related Protein 2; Left; Liver Mitochondria; Mediating; Microinjections; Microscopic Autoradiography; Mitochondria; Mus; NADPH Oxidase; National Institute of Diabetes and Digestive and Kidney Diseases; Natriuresis; Nuclear; Oral; Pathogenesis; Pathway interactions; Patients; Play; Proximal Kidney Tubules; Receptor Signaling; Regulation; Renin-Angiotensin System; Reporting; Resolution; Role; Signal Pathway; Signal Transduction; Stress; Stroke; Subgroup; Testing; Tissues; United States; acetovanillone; adenoviral-mediated; blood pressure reduction; blood pressure regulation; caveolin 1; extracellular; male; mitochondrial dysfunction; multiphoton imaging; novel; overexpression; pressure; promoter; protective effect; receptor; respiratory; response

In the United States, one in three adults will develop hypertension and require antihypertensive treatments in their lifetime. Yet only 1/2 of hypertensive patients respond to current antihypertensive drugs, and 1/3 of hypertensive patients will continue to develop cardiovascular and renal complications. The mechanisms underlying poorly controlled hypertension in response to current antihypertensive therapies remain incompletely understood. Supported by NIDDK grants, we have established that: 1) circulating and tissue ANG II is taken up by the proximal tubule (PT) via AT1a receptor-, the endocytic receptor megalin-, or caveolin 1- dependent mechanisms; 2) internalized ANG II and AT1 (AT1a) receptors are localized in the endosomes and nuclei of PT cells; 3) intracellular microinjection of ANG II increases [Ca ]i, whereas exposure of freshly 2+ isolated renal cortical nuclei with ANG II induces transcriptional TGF-β1, MCP-1, and the Na+/H+ exchanger 3 (NHE3) responses via AT1a receptors; 4) in vitro or intrarenal adenovirus-mediated overexpression of an intracellular ANG II fusion protein with AT1a receptors selectively in the PT induces NHE3 expression, promotes Na+ reabsorption, and increases blood pressure, and 5) global- or kidney-selective deletion of NHE3 attenuates ANG II-induced hypertension. These studies strongly suggest that intracellular ANG II may play an important role in the regulation of Na+ transport in the PT and blood pressure homeostasis. In this A1 revised proposal, we will test a new hypothesis that in the PT of the kidney, ANG II and AT1 (AT1a) are internalized into the mitochondria, where mito-ANG II exerts dual roles on the mitochondrial function via activation of the AT1a/Ca2+/NADPH oxidase/O2.- and the AT2/eNOS/NO/cGMP signaling pathways. Activation of the AT1a/ Ca2+/NADPH oxidase/O2.- pathway induces mitochondrial respiratory and glycolysis stress, impairs pressure natriuresis response, and increases blood pressure, whereas activation of the mitochondrial AT2/eNOS/NO/cGMP pathway by ANG II promotes pressure natriuresis and lowers blood pressure. In Aim 1, we will use high resolution electron microscopic autoradiography and intravital multiphoton imaging to determine whether AT1 (AT1a) and AT2 receptors are localized in the mitochondria of the PT, and whether [125I]- ANG II or Alexa 488®-ANG II is internalized into the mitochondria of the PT in mice. In Aim II, we will determine whether overexpression of a mitochondria-targeting mito-ANG II in PT cells impairs mitochondrial function by activating the AT1a/Ca2+/NADPH oxidase/O2.- signaling pathways, whereas overexpression of mito-AT2R protects mitochondrial function by activating the AT2/eNOS/NO/cGMP signaling. The PT-specific sglt2 promoter and the mitochondria-targeting sequence will be used to drive the overexpression of mito-ANG II, mito-AT1aR or mito-AT2R in PT cells. In Aim III, we will determine whether activation of mito-AT1aR by mito-ANG II in the PT induces mitochondrial respiratory and glycolysis stress, impairs pressure natriuresis responses, and increases blood pressure using specific PT-AT1a-KO, PT-AT2-KO, PT-NHE3-KO, or PT-SIRT3-KO mice, respectively.

在美国，三分之一的成年人会患高血压并需要抗高血压治疗 他们的一生。然而，只有 1/2 的高血压患者对当前的抗高血压药物有反应，1/3 的患者 高血压患者将继续出现心血管和肾脏并发症。机制 对当前抗高血压治疗的潜在高血压控制不佳的情况仍然存在 不完全理解。在 NIDDK 拨款的支持下，我们已经确定：1) 循环和组织 ANG II 通过 AT1a 受体、内吞受体巨蛋白或小窝蛋白 1- 被近端小管 (PT) 吸收 依赖机制； 2) 内化的 ANG II 和 AT1 (AT1a) 受体位于核内体中，并且 PT细胞的细胞核； 3）细胞内显微注射ANG II会增加[Ca ]i，而新鲜的暴露 2+ 分离的肾皮质核与 ANG II 诱导转录 TGF-β1、MCP-1 和 Na+/H+ 交换器 3 (NHE3) 通过 AT1a 受体作出反应； 4) 体外或肾内腺病毒介导的过表达 细胞内 ANG II 融合蛋白与 AT1a 受体选择性地在 PT 诱导 NHE3 表达，促进 Na+ 重吸收，血压升高，5) NHE3 的整体或肾脏选择性缺失会减弱 ANG II 诱发的高血压。这些研究强烈表明细胞内 ANG II 可能发挥重要作用 PT 和血压稳态中 Na+ 转运的调节作用。在此 A1 修订提案中， 我们将测试一个新的假设，即在肾脏的 PT 中，ANG II 和 AT1 (AT1a) 内化到肾脏的 PT 中。 线粒体，mito-ANG II 通过激活线粒体对线粒体功能发挥双重作用 AT1a/Ca2+/NADPH 氧化酶/O2.- 和 AT2/eNOS/NO/cGMP 信号通路。 AT1a/的激活 Ca2+/NADPH 氧化酶/O2.- 途径诱导线粒体呼吸和糖酵解应激，损害 压力尿钠反应，并增加血压，而线粒体的激活 ANG II 的 AT2/eNOS/NO/cGMP 通路可促进压力尿钠排泄并降低血压。在 目标1，我们将使用高分辨率电子显微镜放射自显影和活体多光子成像 确定 AT1 (AT1a) 和 AT2 受体是否位于 PT 的线粒体中，以及是否 [125I]- ANG II 或 Alexa 488®-ANG II 内化至小鼠 PT 的线粒体中。在目标 II 中，我们将确定 PT 细胞中线粒体靶向 mito-ANG II 的过度表达是否会通过以下方式损害线粒体功能： 激活 AT1a/Ca2+/NADPH 氧化酶/O2.- 信号通路，而 mito-AT2R 过度表达 通过激活 AT2/eNOS/NO/cGMP 信号传导来保护线粒体功能。 PT 特异性 SGLT2 启动子 线粒体靶向序列将用于驱动 mito-ANG II、mito-AT1aR 或 PT 细胞中的 mito-AT2R。在目标 III 中，我们将确定 PT 中 mito-ANG II 是否激活 mito-AT1aR 诱导线粒体呼吸和糖酵解应激，损害压力尿钠反应，并增加 分别使用特定的 PT-AT1a-KO、PT-AT2-KO、PT-NHE3-KO 或 PT-SIRT3-KO 小鼠测量血压。