Argininosuccinate lyase is an essential regulator of systemic nitric oxide produc

精氨基琥珀酸裂解酶是全身一氧化氮生成的重要调节剂

基本信息

批准号：
9320990
负责人：
Brendan Lee
金额：
$ 45.59万
依托单位：
BAYLOR COLLEGE OF MEDICINE
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-09-01 至 2019-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9320990
关键词：
Antihypertensive Agents Arginine Argininosuccinate lyase deficiency Biochemical Biological Blood Pressure Blood Vessels Case Study Caveolins Cells Clinical Clinical Research Complex Cross-Over Studies Data Defect Diagnosis Dilatation - action Disease Dose Double-Blind Method Endothelial Cells Enzymes Equilibrium Fibroblasts Genetic study Genotype Heat-Shock Proteins 90 Human Hyperammonemia Hypertension Immunoprecipitation In Vitro Inborn Errors of Metabolism Lead Liver Liver diseases Measures Mediating Modeling Morbidity - disease rate Mus Mutation Natural History Neonatal Screening Neurocognitive Nitrates Nitric Oxide Nitric Oxide Synthase Nitrites Pathogenesis Patients Pharmaceutical Preparations Phenotype Placebo Control Plasma Production Proteins Recurrence Refractory Regulation Reporting Residual state Risk Sodium Nitrite Source Structural Models Supplementation Systemic hypertension Testing Tissues Tracer Translating Vascular Diseases Vascular Endothelium argininosuccinate lyase base brachial artery cohort efficacy study endothelial dysfunction enzyme activity experimental study extracellular gene therapy hepatic ureagenesis in vitro Assay in vivo insight liver function mouse model novel novel therapeutics preclinical study prevent public health relevance response stable isotope treatment response treatment strategy urea cycle

项目摘要

DESCRIPTION (provided by applicant): This renewal application focuses on studying the efficacy of nitric oxide (NO) supplementation as a treatment for the vascular complications in argininosuccinic aciduria (ASA) caused by deficiency of argininosuccinate lyase (ASL), the second most common urea cycle disorder and a human model of nitric oxide (NO) deficiency. ASL serves distinct catalytic vs. structural functions that provide a structural model for understanding why ASA patients defy the arginine paradox, i.e., they are unable to generate NO efficiently in spite of supplemental arginine therapy. In a proof-of-principle case study, we successfully treated an ASA patient with severe hypertension refractory to multiple antihypertensive medications with NO supplementation. Our data imply that NO deficiency at the tissue level contributes to the complications of ASA and preventing hyperammonemia alone may not prevent long-term morbidity. To translate this discovery into a new treatment strategy, we propose to answer the following questions: Aim 1. Can NO supplementation be used to treat endothelial dysfunction in patients with ASA? We will perform a double-blind, placebo-controlled, cross over study in patients with ASA. We hypothesize that a subset of ASA patients will demonstrate endothelial dysfunction due to lack of NOS-dependent NO production from the vascular endothelium and that supplementation with an NOS-independent NO source such as low dose sodium nitrite via the nutriceutical Neo40(R) would correct this defect. Aim 2. Can we develop in vitro assays that predict in vivo clinical response to NO supplementation and clinical variability? We will determine the ability of ASA trial patient fibroblasts to produce NO as measured by nitrite and nitrosothiols and correlate the clinical response and phenotype in Aim 1 with in vitro production of NO in response to arginine supplementation. Aim 3. What is the mechanistic basis of NO regulation by the ASL/NOS complex? NO synthesis may be regulated in part by the participation of NOS in both positive and negative regulatory complexes. To explore the mechanisms that regulate these structural complexes, we will test the hypothesis that NO production is controlled by a balance of negative regulatory complex involving NOS and caveolin vs. a positive, synthetic complex involving NOS and ASL. The insights from these studies may offer a paradigm for studying the diverse biological effects of NO in other disease contexts. While the pathogenesis of ASA is complex and may extend to other arginine- dependent mechanisms, our preclinical and clinical studies support the dominant contribution of NO deficiency on the endpoints tested in this study. Moreover, the approaches and mechanisms proposed here may be broadly application to dysregulation of NO in other disease states.

描述（由申请人提供）：本续展申请重点研究补充一氧化氮 (NO) 治疗精氨琥珀酸尿症 (ASA) 血管并发症的功效，该并发症是由于精氨琥珀酸裂解酶 (ASL)（第二常见的尿素）缺乏引起的循环障碍和一氧化氮（NO）缺乏的人体模型。 ASL 具有独特的催化功能和结构功能，为理解为什么 ASA 患者无法克服精氨酸悖论提供了一个结构模型，即尽管进行了补充精氨酸治疗，他们仍无法有效地产生 NO。在一项原理验证案例研究中，我们成功地治疗了一名 ASA 患者，该患者患有严重高血压，对多种抗高血压药物均无效，且补充一氧化氮。我们的数据表明，组织水平的 NO 缺乏会导致 ASA 并发症，仅预防高氨血症可能无法预防长期发病。为了将这一发现转化为新的治疗策略，我们建议回答以下问题：目标 1. NO 补充剂能否用于治疗 ASA 患者的内皮功能障碍？我们将对 ASA 患者进行双盲、安慰剂对照、交叉研究。我们假设一部分 ASA 患者会因血管内皮缺乏 NOS 依赖性 NO 产生而出现内皮功能障碍，并且通过营养药 Neo40(R) 补充不依赖 NOS 的 NO 源（例如低剂量亚硝酸钠）可以纠正这一问题。这个缺陷。目标 2. 我们能否开发出预测体内对 NO 补充的临床反应和临床变异性的体外测定方法？我们将通过亚硝酸盐和亚硝基硫醇测量确定 ASA 试验患者成纤维细胞产生 NO 的能力，并将目标 1 中的临床反应和表型与响应精氨酸补充的体外 NO 产生相关联。目标 3. ASL/NOS 复合体调节 NO 的机制基础是什么？ NO 合成可能部分受到 NOS 参与正向和负向调节复合体的调节。为了探索调节这些结构复合物的机制，我们将检验这样的假设：NO 的产生是由涉及 NOS 和 Caveolin 的负调节复合物与涉及 NOS 和 ASL 的正合成复合物的平衡控制的。这些研究的见解可能为研究 NO 在其他疾病中的多种生物学效应提供范例。虽然 ASA 的发病机制很复杂，并且可能延伸到其他精氨酸依赖性机制，但我们的临床前和临床研究支持 NO 缺乏对本研究测试的终点的主要贡献。此外，本文提出的方法和机制可能广泛应用于其他疾病状态下的 NO 失调。