Role of Intracrine Angiotensin II in Kidney Cells

内分泌血管紧张素 II 在肾细胞中的作用

• 批准号: 7193516
• 负责人: Jia L. Zhuo
• 金额: $ 24.03万
• 依托单位: HENRY FORD HEALTH SYSTEM
• 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 2009-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7193516
• 关键词: AGTR2 gene; ATP phosphohydrolase; Agonist; Analytical Biochemistry; Angiotensin II; Angiotensin II Receptor; Angiotensinogen; Arts; Binding; Biochemical; Biological; Blood Pressure; Brush Border; CCL2 gene; Ca(2+)-Transporting ATPase; Calcium; Calcium Channel; Cardiovascular system; Cell Nucleus; Cell Surface Receptors; Cell surface; Cells; Chronic; Colchicine; Complex; Confocal Microscopy; Cytoplasm; Cytoplasmic and Nuclear Receptors; Development; Doctor of Medicine; Doctor of Philosophy; Dose; Electrons; Embryo; Endocytosis; Exposure to; Figs - dietary; Flow Cytometry; Fluid Balance; Fluorescein; Fluoresceins; Fluorescence; Future; Genetic Transcription; Growth; Growth Factor; Hormones; Human; Hypertension; Image; Immunohistochemistry; In Transferrin; In Vitro; Inflammatory; Infusion procedures; Injury; Kidney; Kidney Diseases; Knowledge; Label; Liquid substance; Localized; Mediating; Messenger RNA; Microinjections; Microscopic; Microscopic Autoradiography; Molecular Biology; Molecular and Cellular Biology; Mus; Mutate; NF-kappa B; Northern Blotting; Nuclear; Nuclear Receptors; Organ; Pathway interactions; Personal Satisfaction; Phosphorylation; Physiological; Physiology; Play; Process; Property; Protein Kinase C; RNA; Rattus; Research Personnel; Role; Signal Pathway; Site; Sodium; Sucrose; TNF gene; Testing; Tubular formation; activating transcription factor; ataxia telangiectasia mutated protein; basolateral membrane; cell growth; citrate carrier; cytokine; drug development; extracellular; in vivo; inhibitor/antagonist; insight; interstitial; kidney cell; mRNA Expression; novel; oxophenylarsine; prevent; programs; receptor; receptor mediated endocytosis; response; trafficking; transcription factor; uptake

DESCRIPTION (provided by applicant): Angiotensin II (Ang II) plays an essential role in maintaining body sodium and fluid balance and normal blood pressure by regulating proximal tubular sodium reabsorption. Ang II exerts powerful effects on sodium transport and cell growth by activating cell surface receptors on brush borders and basolateral membranes of proximal tubule cells. However, we have new evidence that a) extracellular Ang II is taken up by proximal tubule cells in vivo and in vitro; b) microinjection of Ang II directly into the cells increases intracellular calcium; and c) Ang II induces RNA transcription and expression in isolated nuclei. Our results suggest that internalized Ang II may act as an intracellular hormone to play important physiological and pathological roles in these cells. In this project, we propose to test the general hypothesis that extracellular Ang II is taken up by proximal tubule cells through AT1A receptor-mediated internalization, and that internalized Ang II binds to cytoplasmic and nuclear receptors to induce intracellular responses. To test this hypothesis, we will conduct both in vitro and in vivo studies, using complementary biochemical, morphological, cellular and molecular biology approaches. In Aim I, we will study whether proximal tubular cells take up extracellular Ang II in vitro and in vivo and elucidate the mechanisms by which Ang II receptors and the endocytotic machinery regulate Ang II trafficking. In Aim II, we will use confocal microscopy, state-of-the-art EM autoradiography and immunohistochemistry to trace intracellular trafficking pathways of internalized Ang II to the endosomal compartments and its translocaUon to the nucleus in vitro and in vivo. In Aim III we will study whether microinjection of Ang II increases intracellular calcium through activation of cytoplasmic AT1 receptors and the cellular mechanisms involved. Finally, in Aim IV we will investigate whether internalized Ang II binds to intracellular Ang II receptors to activate transcription factor NFkappaB and its translocation to the nucleus, and whether internalized Ang II stimulates nuclear receptors to increase transcription and expression of the Na+/H+ exchanger NHE3 and pro-inflammatory cytokines. These studies will provide new insights into the important role of internalized Ang II in renal physiology and Ang II-induced hypertensive renal injury.

描述（申请人提供）：血管紧张素II（Ang II）通过调节近端肾小管钠重吸收，在维持体内钠和液体平衡以及正常血压方面发挥重要作用。 Ang II 通过激活近端小管细胞刷状缘和基底外侧膜上的细胞表面受体，对钠转运和细胞生长产生强大的影响。 然而，我们有新的证据表明a）细胞外Ang II在体内和体外被近曲小管细胞吸收； b) 将血管紧张素II直接显微注射到细胞中增加细胞内钙； c) Ang II 在分离的细胞核中诱导 RNA 转录和表达。 我们的结果表明，内化的 Ang II 可能作为细胞内激素在这些细胞中发挥重要的生理和病理作用。 在本项目中，我们建议测试以下一般假设：细胞外 Ang II 通过 AT1A 受体介导的内化被近端肾小管细胞摄取，并且内化的 Ang II 与细胞质和核受体结合以诱导细胞内反应。 为了检验这一假设，我们将使用互补的生化、形态学、细胞和分子生物学方法进行体外和体内研究。 在目标 I 中，我们将研究近端肾小管细胞是否在体外和体内摄取细胞外 Ang II，并阐明 Ang II 受体和内吞机制调节 Ang II 运输的机制。 在目标 II 中，我们将使用共聚焦显微镜、最先进的 EM 放射自显影和免疫组织化学来追踪内化 Ang II 到内体区室的细胞内运输途径及其在体外和体内转运到细胞核的途径。 在目标 III 中，我们将研究显微注射 Ang II 是否通过激活细胞质 AT1 受体以及所涉及的细胞机制来增加细胞内钙。 最后，在Aim IV中，我们将研究内化Ang II是否与细胞内Ang II受体结合以激活转录因子NFkappaB及其易位至细胞核，以及内化Ang II是否刺激核受体以增加Na+/H+交换器NHE3和促炎细胞因子的转录和表达。 这些研究将为内化血管紧张素II在肾脏生理学和血管紧张素II诱导的高血压肾损伤中的重要作用提供新的见解。