Endothelin-dependent NOS activation in the kidney

我们以前报道过钠的排泄与硝酸盐/亚硝酸盐的排泄显著相关， cGMP和内皮素。在大鼠和小鼠体内， NOSI通过遗传和药理学抑制延迟钠排泄， 亚硝酸盐/硝酸盐排泄急性盐挑战后。由于钠排泄的最终控制发生在 收集管，我们假设，激活NOSI和NO的生产，在这一点上， 肾单位段促进钠排泄。为了直接验证这一假设，我们最近创建了 集合管特异性NOSI敲除（CD NOSI KO）小鼠。我们的初步数据表明， 与对照小鼠相比，NOSI KO小鼠具有盐依赖性高血压。 与Kohan的实验室合作，我们已经证明了收集导管衍生的 内皮素在基础盐和高盐条件下激活NOS中的作用。体外研究表明 内皮素激活肾髓质集合管细胞中的NOSI。众所周知，收集管道是一个 内皮素的主要来源。因此，我们预测，内皮素刺激NOSI在收集 以自分泌的方式输送。 控制集合管中钠重吸收的已知机制之一是通过亚细胞 上皮钠通道（ENaC）通过胞吞作用从顶膜的运输。最近， 已经表明，NO通过S-亚硝基化激活发动蛋白促进内吞作用， 内皮细胞，尽管尚不清楚这是否发生在集合管中。ENaC贩运是 由动力蛋白依赖的内吞作用调节。我们的初步数据表明，NOSI与 肾内髓质中的发动蛋白。此外，我们的数据表明，发动蛋白是S-亚硝基化的， 肾内髓质我们假设集合管N 0 S1调节动力蛋白依赖性 集合管钠通道的内吞作用。 基于以下目的设计实验： 目标1.为了验证集合管来源的内皮素是一种主要的自分泌调节剂的假设， 在饮食钠变化期间集合管中的NOS 1激活。 目标2.为了检验在集合管中NOSI调节钠的内吞作用的假设， 通过依赖动力的机制。

We previously reported that sodium excretion is significantly correlated to the excretion of nitrate/nitrite, cGMP, and endothelin in normotensive young adults. In rats and mice in vivo, loss of functional NOSI through both genetic and pharmacological inhibition delays the excretion of sodium and blunts nitrite/nitrate excretion following an acute salt challenge. Since the final control of sodium excretion occurs in the collecting duct, we have hypothesized that the activation of NOSI and NO production in this nephron segment facilitates sodium excretion. To directly test this hypothesis, we have recently created collecting duct specific NOSI knockout (CD NOSI KO) mice. Our preliminary data indicates that the CD NOSI KO mice have salt-dependent hypertension compared to control mice. In collaboration with Kohan's laboratory, we have demonstrated a role for collecting duct-derived endothelin in the activation of NOS under basal and high salt conditions. In vitro studies have shown that endothelin activates NOSI in renal medullary collecting duct cells. It is known that the collecting duct is a major source of endothelin. Thus, we have predicted that endothelin stimulates NOSI in the collecting duct in an autocrine manner. One of the known mechanisms that controls sodium reabsorption in the collecting duct is via subcellular trafficking of the epithelial sodium channel (ENaC) from the apical membrane via endocytosis. Recentiy, it has been shown that NO promotes endocytosis via activation of dynamin through S-nitrosylation in endothelial cells, although it is unknown whether this occurs in the collecting duct. ENaC trafficking is regulated by dynamin-dependent endocytosis. Our preliminary data demonstrates that NOSI interacts with dynamin in the renal inner medulla. Furthermore, our data indicates that dynamin is S-nitrosylated in the renal inner medulla. We have hypothesized that collecting duct N0S1 regulates dynamin-dependent endocytosis of collecting duct sodium channels. Experiments are designed based on the following aims: Aim 1. To test the hypothesis that collecting duct-derived endothelin is a major autocrine regulator of N0S1 activation In the collecting duct during changes In dietary sodium. Aim 2. To test the hypothesis that in the collecting duct, NOSI regulates endocytosis of sodium channels via a dynamin-dependent mechanism.