TETRAHYDROBIOPTERIN--REGULATOR OF ENDOTHELIAL FUNCTION

四氢生物蝶呤--内皮功能调节剂

• 批准号: 2231497
• 负责人: Zvonimir S Katusic
• 金额: $ 19.49万
• 依托单位: MAYO CLINIC ROCHESTER
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-12-01 至 1999-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2231497
• 关键词: angiography; biological signal transduction; cerebral artery; chemical synthesis; cofactor; coronary artery; cyclic AMP; cyclic GMP; dogs; enzyme activity; enzyme mechanism; gene expression; genetic library; guanosine triphosphate; guanylate cyclase; hydrogen peroxide; hydrolase; muscle function; nitric oxide synthase; polymerase chain reaction; pteridine analog; radioimmunoassay; tissue /cell culture; vascular endothelium; vascular smooth muscle

L-Arginine/nitric oxide pathway plays a key role in regulation of arterial tone. Biosynthesis of nitric oxide requires activation of nitric oxide synthase in the presence of tetrahydrobiopterin as a cofactor. The proposition to be tested is that in vascular endothelial cells suboptimal concentrations of tetrahydrobiopterin may favor nitric oxide synthase- catalyzed production of hydrogen peroxide. Protocols are designed to determine if in coronary arteries with impaired tetrahydrobiopterin biosynthesis, hydrogen peroxide may replace nitric oxide as mediator of endothelium-dependent relaxations. Mechanisms of relaxations to hydrogen peroxide will be studied and levels of cyclic GMP will be measured in order to characterize the role of soluble guanylate cyclase. Hydrogen peroxide is a potent oxidant and it is expected that these studies may provide new information concerning the role of dysfunctional nitric oxide synthase in endothelial injury. Since de novo synthesis of tetrahydrobiopterin is regulated by enzymatic activity of GTP cyclohydrolase I, molecular mechanisms regulating expression of mRNA isoforms encoding for this protein will be studied. Activity of GTP cyclohydrolase I and concentrations of tetrahydrobiopterin in endothelial cells will be measured. Preliminary studies demonstrated that type 1 GTP cyclohydrolase I is expressed in human aortic endothelial cells. Identification of signal transduction pathways involved in control of gene expression, as well as activity of GTP cyclohydrolase I, will provide a molecular basis for understanding of mechanisms responsible for impairment of tetrahydrobiopterin biosynthesis and dysfunction of nitric oxide synthase. In order to determine whether dysfunction could be corrected by exogenous pterins, vascular effects of tetrahydrobiopterin and 6-methyl- tetrahydropterin on mechanisms of endothelium-dependent relaxations in control arteries and arteries with impaired tetrahydrobiopterin biosynthesis will be investigated. Canine basilar arteries will be used as a model to study the inhibitory effects of pterins on endothelium- dependent contractions. The effect of pterins on production of cyclic GMP, cyclic AMP as well as on prostanoid production associated with endothelium-dependent contractions will be measured. These experiments will reveal whether pterins may affect balance between relaxing and contracting factors released from endothelium. It is anticipated that results of this proposal will define the role of tetrahydrobiopterin in regulation of endothelial function. The proposed studies may also help to identity if impaired tetrahydrobiopterin biosynthesis may contribute to initial endothelial injury known to be a key event in the pathogenesis of vascular diseases.

L-精氨酸/一氧化氮途径在动脉粥样硬化的调节中起关键作用 语气一氧化氮的生物合成需要激活一氧化氮 在四氢生物蝶呤作为辅因子的存在下，的 有待检验的命题是，在血管内皮细胞中， 四氢生物蝶呤的浓度可能有利于一氧化氮合酶- 催化生产过氧化氢。协议旨在 确定四氢生物蝶呤受损的冠状动脉中 生物合成，过氧化氢可以取代一氧化氮作为介体， 内皮依赖性舒张。氢弛豫机制 过氧化物将被研究，环鸟苷酸的水平将被测量， 以表征可溶性鸟苷酸环化酶的作用。氢 过氧化物是一种有效的氧化剂，预计这些研究可能 提供有关功能失调的一氧化氮的作用的新信息， 合酶在内皮损伤中的作用由于从头合成 四氢生物蝶呤受GTP酶活性调节 环化水解酶I，调控mRNA表达的分子机制 将研究编码该蛋白的同种型。GTP活性 环化水解酶I和内皮细胞中四氢生物蝶呤的浓度 细胞将被测量。初步研究表明，1型GTP 环水解酶I在人主动脉内皮细胞中表达。 参与基因调控的信号转导途径的鉴定 GTP环化水解酶I的表达以及活性，将提供一种 理解损伤机制的分子基础 四氢生物蝶呤生物合成和一氧化氮功能障碍 合成酶为了确定功能障碍是否可以通过 外源性蝶呤，四氢生物蝶呤和6-甲基- 四氢蝶呤对内皮依赖性舒张机制影响 控制动脉和四氢生物蝶呤受损的动脉 将研究生物合成。犬基底动脉将用作 研究蝶呤对内皮细胞的抑制作用的模型- 依赖性收缩蝶呤对环鸟苷酸产生的影响， 环AMP以及与前列腺素相关的前列腺素类产生 将测量内皮依赖性收缩。这些实验 将揭示蝶呤是否会影响放松和放松之间的平衡， 内皮细胞释放的收缩因子。 预计各国 该提案的结果将确定四氢生物蝶呤在以下方面的作用： 调节内皮功能。拟议的研究也可能有助于 如果四氢生物蝶呤生物合成受损， 已知初始内皮损伤是 血管疾病