Cationic Amino Acid Transporters and Lung NO Production

阳离子氨基酸转运蛋白和肺 NO 产生

• 批准号: 7032108
• 负责人: LEIF D NELIN
• 金额: $ 33.2万
• 依托单位: RESEARCH INST NATIONWIDE CHILDREN'S HOSP
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-02-03 至 2010-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7032108
• 关键词: Adenoviridae; aminoacid transport; arginine; cations; enzyme activity; gene expression; hypoxia; inflammation; laboratory rat; lipopolysaccharides; lung; lung injury; mitogen activated protein kinase; nitric oxide; nitric oxide synthase; protein isoforms; protein structure function; protein tyrosine kinase; respiratory function; small interfering RNA; tissue /cell culture; transfection /expression vector; tumor necrosis factor alpha; vascular endothelium; vasomotion; western blottings

DESCRIPTION (provided by applicant): Nitric oxide (NO) is an important molecule involved in a myriad of physiological functions. In pulmonary hypertensive diseases, NO production is decreased resulting in vasoconstriction and vascular remodeling. While in pulmonary inflammatory diseases, NO production is increased resulting in tissue damage. NO is generated from L-arginine (L-arg) by the NO synthases (NOS). The cellular bioavailability of L-arg to NOS is determined in large part by uptake of extracellular L-arg via the cationic amino acid transporters (CAT). Preliminary studies suggest that manipulation of L-arg uptake modifies clinically important parameters in highly vulnerable patient populations. Thus, the studies described in the present application are focused on elucidation of the functional and mechanistic aspects of endothelial cell uptake of L-arg by CAT and its role in regulation of NO production in the lung. The long-term goals of these studies are to develop therapies that increase NO production by facilitating CAT-mediated L-arg uptake in pulmonary hypertensive diseases, and that decrease NO production by inhibiting CAT-mediated L-arg uptake in inflammatory lung diseases. The working hypothesis is that NO production can be modulated by control of L-arg bioavailability to NOS through alterations in CAT-mediated L-arg transport. The studies will address the hypothesis in three specific aims: 1) to test the hypothesis that alterations in CAT activities regulate NO production by altering the bioavailability of L-arg to NOS; 2) to test the hypothesis that Src-family tyrosine kinases and mitogen-activated protein kinases mediate inflammation-induced alterations in the expression of CAT and/or NOS; and 3) to test the hypothesis that gene transfer to regulate CAT expression in vivo will affect NO production in the lung, and thereby affect pulmonary vasomotor tone and lung injury. RELEVANCE: Therapies aimed at manipulating NO-mediated effects in lung diseases have centered on pharmacological inhibition of NO production or inhalation of exogenous NO, however a majority of these critically ill patients do not respond to these therapies. L-arg uptake represents a rate-limiting step in lung NO production. The present proposal will provide translational data necessary for the design of rational clinical trials to determine safe and effective pharmacological and genetic manipulations of L-arg uptake rates, and thereby NO production, in severe pulmonary diseases, such as ARDS and pulmonary hypertension.

描述（由申请人提供）：一氧化氮（NO）是参与多种生理功能的重要分子。在肺动脉高压疾病中，NO产生减少，导致血管收缩和血管重塑。而在肺部炎症性疾病中，NO产生增加，导致组织损伤。NO由L-精氨酸（L-arg）通过NO还原酶（NOS）产生。L-arg对NOS的细胞生物利用度在很大程度上取决于通过阳离子氨基酸转运蛋白（CAT）摄取细胞外L-arg。初步研究表明，操纵L-arg摄取修改临床上重要的参数，在高度脆弱的患者群体。因此，本申请中描述的研究集中于阐明CAT对L-arg的内皮细胞摄取的功能和机制方面及其在肺中NO产生的调节中的作用。这些研究的长期目标是开发通过促进CAT介导的L-arg摄取在肺动脉高压疾病中增加NO产生的疗法，以及通过抑制CAT介导的L-arg摄取在炎性肺病中减少NO产生的疗法。工作假设是NO的产生可以通过改变CAT介导的L-arg转运来控制L-arg对NOS的生物利用度来调节。本研究将从三个方面来探讨这一假说：1）验证CAT活性的改变通过改变L-arg对NOS的生物利用度来调节NO产生的假说; 2）验证Src家族酪氨酸激酶和丝裂原活化蛋白激酶介导炎症诱导的CAT和/或NOS表达的改变的假说;以及3）验证体内基因转移调节CAT表达将影响肺中NO的产生，从而影响肺血管张力和肺损伤的假设。 相关性：旨在操纵NO介导的肺部疾病作用的治疗集中在NO产生的药理学抑制或外源性NO的吸入，然而，这些危重患者中的大多数对这些治疗没有反应。L-arg摄取代表肺NO产生的限速步骤。本提案将提供必要的翻译数据的设计合理的临床试验，以确定安全和有效的药理学和遗传操作的L-arg摄取率，从而NO的生产，在严重的肺部疾病，如ARDS和肺动脉高压。