Regulation of NOS Activity in the Kidney & Hypertension

肾脏中 NOS 活性的调节

• 批准号: 7595338
• 负责人: Jeffrey L. Garvin
• 金额: $ 37.66万
• 依托单位: HENRY FORD HEALTH SYSTEM
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-04-01 至 2014-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7595338
• 关键词: 1-Phosphatidylinositol 3-Kinase; Affect; Apyrase; Arginine; Autacoids; Bicarbonates; Binding; Biochemical; Blood; Blood Pressure; Blood Vessels; Chelating Agents; Cultured Cells; Cyclic AMP; Cyclic GMP; Data; Defect; Dominant-Negative Mutation; Endothelial Cells; Enzymes; Epithelial Cells; Excretory function; Hexoses; Hypertension; In Vitro; Ions; Kidney; Knockout Mice; Lead; Limb structure; Measures; Mechanics; Mediating; Methods; NOS3 gene; Nitric Oxide; Nitric Oxide Synthase; Phosphotransferases; Physiological; Production; Rattus; Regulation; Reporting; Resistance; Role; Small Interfering RNA; Sodium Chloride; Stretching; TRPV channel; Testing; Thick; Vanilloid; absorption; blood pressure regulation; human NOS3 protein; hypertension treatment; in vivo; inhibitor/antagonist; luminal membrane; molecular imaging; new therapeutic target; novel; phosphoric diester hydrolase; pressure; prevent; receptor; response; salt sensitive; shear stress; sodium-potassium chloride cotransporter 2 protein

Nitric oxide (NO)reduces blood pressure by dilating blood vessels and promoting renal salt excretion. Thick ascending limbs absorb 30% of the filtered NaCI. Inappropriate salt retention by this segment leads to hypertension. We reported that NO produced by NO synthase (NOS) 3 in the thick ascending limb acts as an autacoid to inhibit transport. Flow augments NOS 3 activity via mechano-sensitive channels in endothelial cells. Our preliminary data show that luminal flow activates NOS 3 in thick ascending limbs and this requires translocation of the enzyme to the luminal membrane. However, it is not known how luminal flow regulates NOS 3 activity in this segment or how flow-induced NO affects NaCI reabsorption. We hypothesize that increasing luminal flow in thick ascending limbs stimulates NO production by NOS 3 via activation of mechano-sensitive TRPV4 channels, release of ATP and activation of Akt.The NO thus produced blunts NaCI reabsorption. Defects in the response to flow-stimulated NO production enhance salt retention and promote salt-sensitive hypertension. This hypothesis will be tested in 4 aims. Aim I. Hypothesis: Increasing luminal flow causes translocation and activation of NOS 3, stimulating NO production by the thick ascending limb due to increased shear stress. Aim II. Hypothesis: Luminal flow enhances NOS 3 activity by activating TRPV 4 channels and causing local increases in intracellular Ca. Aim III.Hypothesis: TRPV 4 activation by luminal flow induces release of ATP, which binds to purinergic 2 receptors and activates phosphatidylinositol 3 kinase, Akt and NOS 3. Aim IV: Hypothesis: Flow-stimulated NO production inhibits Na reabsorption by thick ascending limbs via activation of cGMP-stimulated phosphodiesterase 2 and reductions in cAMP. Defects in the response to flow-enhanced NO production promote salt retention and salt-sensitive hypertension. We will study how flow stimulates NO in perfused tubules and cultured cells using physiological, imaging, molecular and biochemical methods. Project 1 relates to the central theme since it will study renal NOS 3 regulation and the effects of NO on salt absorption. Information from Project 1 will be integrated with that from all other projects. It will use all of the cores. These will be the first studies to define how flow activates NOS 3, its effects on Na reabsorption by the thick ascending limb and whether these effects are blunted in salt-sensitive hypertension. This information may lead to new therapeutic targets for the treatment of hypertension.

一氧化氮 (NO) 通过扩张血管和促进肾盐排泄来降低血压。厚的 上升肢吸收 30% 的过滤后的 NaCl。该部分不适当的盐保留会导致 高血压。我们报道了厚升肢中NO合酶（NOS）3产生的NO充当 自体物质抑制运输。流量通过内皮细胞中的机械敏感通道增强 NOS 3 活性 细胞。我们的初步数据表明，腔内血流激活粗上行肢中的 NOS 3，这需要 酶易位至腔膜。然而，尚不清楚管腔流量如何调节 该节段中的 NOS 3 活性或流量诱导的 NO 如何影响 NaCl 重吸收。我们假设 增加粗壮上升肢的管腔流量可通过激活 NOS 3 刺激 NO 产生 机械敏感的 TRPV4 通道，释放 ATP 并激活 Akt。NO 由此产生钝化 氯化钠重吸收。对流动刺激的 NO 产生的反应缺陷会增强盐保留和 促进盐敏感性高血压。该假设将在 4 个目标中进行检验。目标 I. 假设：增加 腔内血流引起 NOS 3 的易位和激活，刺激浓密上升的 NO 产生 由于剪切应力增加而导致肢体变形。目标二。假设：管腔流量通过激活 NOS 3 来增强 NOS 3 活性 TRPV 4 通道并导致细胞内 Ca 的局部增加。目标 III.假设：TRPV 4 激活 管腔流量诱导 ATP 释放，ATP 与嘌呤能 2 受体结合并激活磷脂酰肌醇 3 激酶、Akt 和 NOS 3. 目标 IV：假设：流量刺激的 NO 产生通过以下方式抑制 Na 重吸收： 通过激活 cGMP 刺激的磷酸二酯酶 2 和减少 cAMP，使上肢变粗。 对流量增强的 NO 产生的响应缺陷会促进盐保留和盐敏感 高血压。我们将研究流动如何刺激灌注小管和培养细胞中的 NO 生理学、成像、分子和生化方法。项目 1 与中心主题相关，因为它 将研究肾脏NOS 3 调节以及NO 对盐吸收的影响。来自项目 1 的信息将是 与所有其他项目的集成。它将使用所有核心。这些将是第一个定义 血流如何激活 NOS 3，其对粗升肢 Na 重吸收的影响以及这些是否 对盐敏感的高血压的作用会减弱。这些信息可能会带来新的治疗靶点 高血压的治疗。