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.

说明(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侧膜上的细胞表面受体，对钠转运和细胞生长发挥强大的作用。然而，我们有新的证据表明，a)细胞外Ang II被体内和体外的近端小管细胞摄取；b)Ang II直接显微注射到细胞内增加细胞内钙；c)Ang II诱导分离的细胞核中的RNA转录和表达。我们的结果提示内在化的Ang II可能作为一种细胞内激素在这些细胞中发挥重要的生理和病理作用。在这个项目中，我们建议检验一个普遍的假设，即细胞外的Ang II是通过AT1a受体介导的内化被近端小管细胞摄取的，内化的Ang II与细胞质和核受体结合来诱导细胞内反应。为了验证这一假设，我们将进行体外和体内研究，使用互补的生化、形态、细胞和分子生物学方法。在目标I中，我们将研究近端肾小管细胞在体外和体内是否摄取细胞外的Ang II，并阐明Ang II受体和内吞机制调节Ang II转运的机制。在AIM 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的Ang II在体外和体内的细胞内转运途径和转运到细胞核的途径。在AIM III中，我们将研究微量注射Ang II是否通过激活胞浆AT1受体而增加细胞内钙及其相关的细胞机制。最后，在目标IV中，我们将研究内化的Ang II是否与细胞内的Ang II受体结合以激活转录因子NFkappaB及其转位到细胞核，以及内化的Ang II是否刺激核受体增加Na+/H+交换器NHE3和促炎细胞因子的转录和表达。这些研究将为内在化Ang II在肾脏生理和Ang II诱导的高血压肾损伤中的重要作用提供新的见解。