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: 10174147
• 负责人: Jia L. Zhuo
• 金额: $ 28.69万
• 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: 2020-03-01 至 2022-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10174147
• 关键词: Novel; Roles; Mitochondrial; Angiotensin; II

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，三分之一的成年人将患上高血压，并需要在 他们的一生。然而，只有1/2的高血压患者对当前的降压药反应，1/3 高血压患者将继续发展心血管和肾脏并发症。机制 潜在的对当前降压治疗的高血压控制不良的高血压仍然 不完全理解。在NIDDK赠款的支持下，我们确定：1）循环和组织ANG II被AT1A受体，内吞受体Megalin-或Caveolin 1-近端小管（PT）吸收。 依赖机制； 2）内部化的ANG II和AT1（AT1A）受体位于内体中，并且 Pt细胞的核； 3）ANG II的细胞内显微注射增加[Ca] I，而新鲜的暴露 2+ ANG II的分离肾皮质核会诱导转录TGF-β1，MCP-1和Na+/H+交换器3 （NHE3）通过AT1A受体的反应； 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受体在PT中有选择地诱导NHE3表达，促进 Na+吸收并增加血压，5）NHE3的全球或肾脏选择性缺失减弱 ANG II引起的高血压。这些研究强烈表明，细胞内ANG II可能起重要 在PT和血压稳态中Na+转运调节中的作用。在此A1修订的建议中， 我们将检验一个新的假设，即在肾脏，ANG II和AT1（AT1A）的PT中被内部化为 线粒体，线粒体II通过激活在线粒体功能上发挥双重作用 AT1A/CA2+/NADPH氧化酶/O2.-和AT2/ENOS/NO/CGMP信号通路。激活AT1A/ Ca2+/NADPH氧化酶/O2。-途径诱导线粒体呼吸和糖酵解应激，损害 压力纳地尿反应并增加血压，而线粒体的激活 ANG II的AT2/ENOS/NO/CGMP途径促进了纳地液的压力并降低了血压。在 AIM 1，我们将使用高分辨率电子显微镜放射自显影和浸润性多光子成像 确定AT1（AT1A）和AT2受体是否位于PT的线粒体中，以及[125i] - 是否存在 Ang II或Alexa488®-ANG II将小鼠的PT线粒体内部化。在AIM II中，我们将确定 PT细胞中线粒体靶向线粒体的线粒体II的过表达是否会损害线粒体功能 激活AT1A/CA2+/NADPH氧化酶/O2。-信号通路，而Mito-AT2R的过表达 通过激活AT2/ENOS/NO/CGMP信号来保护线粒体功能。 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AIM III中，我们将确定Mito-ang II在PT中激活Mito-AT1AR是否激活 线粒体呼吸道和糖酵解应激，损害压力纳地尿反应，并增加 分别使用特定的PT-AT1A-KO，PT-AT2-KO，PT-NHE3-KO或PT-SIRT3-KO小鼠的血压。