Regulation of NOS Activity in the Kidney & 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 上升肢吸收30%的过滤的NaCl。这一部分的不适当的盐保留导致 高血压我们报道了在粗的升支中由NO合酶（NOS）3产生的NO作为一种抑制剂， 抑制运输的autacoid。血流通过机械敏感性通道增强内皮细胞NOS3活性 细胞我们的初步数据显示，管腔血流激活了粗大的上行支中的NOS3， 转移酶的腔膜。然而，尚不清楚管腔流量如何调节 NOS3活性在这段或如何流量诱导NO影响NaCl重吸收。我们假设 在粗大的上行支中增加管腔血流通过激活 机械敏感性TRPV4通道，ATP释放和Akt激活。 NaCl重吸收。对流动刺激的NO产生的反应缺陷增强了盐的保留， 促进盐敏感性高血压。这一假设将在4个目标中进行检验。艾姆岛假设：增加 管腔血流引起NOS3移位和激活，刺激NO的产生， 由于剪切应力的增加而导致肢体的损伤。Aim II.假设：管腔血流通过激活 TRPV 4通道和引起细胞内Ca的局部增加。目的III.假设：TRPV 4活化， 腔流诱导ATP的释放，ATP结合嘌呤能2受体并激活磷脂酰肌醇 3激酶、Akt和NOS 3.目的IV：假设：流量刺激的NO产生通过以下途径抑制Na重吸收： 通过激活cGMP刺激的磷酸二酯酶2和减少cAMP，使上升肢体变粗。 对流动增强的NO产生的响应中的缺陷促进盐保留和盐敏感性。 高血压我们将研究如何流刺激一氧化氮在灌流小管和培养细胞， 生理学、成像、分子和生物化学方法。项目1与中心主题有关，因为它 研究肾脏NOS3的调节及NO对盐吸收的影响。项目1的信息将 与其他所有项目相结合。它将使用所有的核心。这将是第一个研究， 血流如何激活NOS3，它对粗的上升支钠重吸收的影响，以及这些 在盐敏感性高血压中效果减弱。这些信息可能会导致新的治疗目标， 高血压的治疗

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.