Regulation of NOS Activity in the Kidney & Hypertension

一氧化氮(NO)通过扩张血管和促进肾脏盐分排泄来降低血压。厚 上升的肢体吸收过滤后的纳西的30%。这一部分不适当的盐分保留会导致 高血压。我们报道了由粗大的升肢中的一氧化氮合酶(NOS)3产生的NO作为一种 可抑制运输的金丝雀形细胞。血流通过内皮细胞机械敏感通道增强一氧化氮合酶活性 细胞。我们的初步数据显示，管腔血流激活了粗大的上升肢体中的NOS3，这需要 酶转移到管腔膜上。然而，还不知道管腔流动是如何调节的。 NO在这一部分的活性或流动诱导的NO如何影响NaCI的重吸收。我们假设 粗大升肢的管腔血流增加通过激活NOS3刺激NO的产生 机械敏感的TRPV4通道、ATP的释放和Akt的激活。NO因此产生钝化 NaCI重吸收。对流动刺激的NO产生的反应缺陷增加了盐分滞留和 推广盐敏感型高血压。这一假设将在4个目标中得到检验。目标一.假设：增长 腔内血流引起NOS3的移位和激活，通过粗大的上行刺激NO的产生 肢体由于剪应力增加。目的II.假设：腔内血流通过激活 TRPV4通道，并引起局部细胞内钙升高。目的III.假设：TRPV4通过 腔内血流诱导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NOS3。目的IV：假设：流动刺激的NO产生抑制钠的重吸收 粗大的上肢通过激活cGMP刺激的磷酸二酯酶2和cAMP的减少。 流动促进NO产生的反应缺陷促进了盐滞留和盐敏性 高血压。我们将研究血流如何刺激灌流的小管和培养的细胞中的NO 生理、成像、分子和生化方法。项目1与中心主题有关，因为它 将研究肾脏NOS3的调节以及NO对盐吸收的影响。来自项目1的信息将是 与所有其他项目的信息集成在一起。它将使用所有内核。这些将是第一批确定 血流是如何激活NOS3的，它对粗大的升支重吸收钠的影响，以及这些 盐敏感型高血压的影响是迟钝的。这一信息可能会导致新的治疗靶点 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.