VASCULAR CELL CATIONIC AMINO ACID TRANSPORT & METABOLISM

血管细胞阳离子氨基酸运输

• 批准号: 6184800
• 负责人: Andrew I Schafer
• 金额: $ 30.05万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-04-01 至 2003-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6184800
• 关键词: aminoacid metabolism; aminoacid transport; arginine; cell proliferation; collagen; cytokine; enzyme mechanism; extracellular matrix; gene expression; genetically modified animals; growth factor; injury; laboratory mouse; ornithine; ornithine decarboxylase; protein biosynthesis; tissue /cell culture; transaminases; vascular smooth muscle

The basic molecular and biological mechanisms involved in the vascular response to injury have yet to be clearly defined. Convergence of findings from several lines of studies in the laboratory of the P.I. has led to an emerging new model which suggests that cationic amino acid (L- arginine, L-ornithine) transport and metabolism are critical processes in modulating the response to vascular injury. The basic hypothesis of this proposed project is that biochemical mediators (growth factors, cytokines), hemodynamic forces (shear stress, cyclic stretch), and injury all act as stimuli of cationic amino acid transport in vascular smooth muscle cells (SMC) but exert highly selective and divergent actions on the intracellular pathways of L-arginine and L-ornithine metabolism. Further, it is proposed that these pathways are critical regulators of the major processes of vascular remodeling, including SMC proliferation and extracellular matrix collagen synthesis: L-ornithine- derived polyamines and L-proline promote these activities, while L- arginine-derived nitric oxide inhibits them. This project will study this problem and further develop this new model utilizing three linked specific aims that utilize complementary in vitro and in vivo approaches. First, experiments are designed to elucidate the control of L-arginine/L-ornithine transport and metabolism by growth factors and cytokines in cultured SMC. Studies will examine the growth factor and cytokine control of the functions and gene expression of vascular SMC cationic amino acid transporters (CATs), and the L-ornithine- metabolizing enzymes, ornithine decarboxylase and aminotransferase. Second, studies are proposed to examine the effect of the more complex, pathophysiologically relevant hemodynamic stimuli of cyclic stretch and shear stress on vascular SMC L-arginine/L-ornithine transport and metabolism. Third, these in vitro findings will be applied to an in vivo-model of vascular injury. Experiments will be performed to study the regulation of L-arginine/L-ornithine transport and metabolism, including their roles in SMC proliferation and extracellular matrix collagen synthesis, using a well characterized model of arterial injury in mice. Using pharmacologic, and ultimately transgenic approaches, this model should help define the biological roles of SMC cationic amino acid transport and metabolism in vascular remodeling in vivo. Elucidation of the molecular mechanisms that modulate the response to vascular injury will provide new rational targets for therapeutic intervention.

血管反应涉及损伤的基本分子和生物学机制尚未明确定义。来自P.I.实验室的几项研究的发现的收敛导致了一个新的新模型，该模型表明阳离子氨基酸（L-精氨酸，L-雌性氨酸）的转运和代谢是调节对血管损伤反应的关键过程。 该提出的项目的基本假设是，生化介质（生长因子，细胞因子），血液动力学力（剪切应力，环状拉伸）和损伤都充当阳离子氨基酸在血管平滑肌细胞（SMC）中的刺激（SMC）的刺激性，但在l-arithininine和l-arithininine的内部细胞素构素中对高度选择性和分歧作用。 此外，有人提出这些途径是血管重塑主要过程的关键调节剂，包括SMC增殖和细胞外基质胶原蛋白合成：L-雌氨酸衍生的多胺和L-丙啉蛋白和L-丙啉活性，而L-精氨酸衍生的硝酸氧化物则抑制它们。 该项目将研究此问题，并利用三个利用互补体外和体内方法的链接特定目的进一步开发这种新模型。 首先，设计实验旨在阐明通过培养的SMC中生长因子和细胞因子对L-精氨酸/L-雌性转运和代谢的控制。研究将检查血管SMC阳离子氨基酸转运蛋白（CAT）的功能和基因表达的生长因子和细胞因子的控制，以及L-厄氨生活代谢酶，鸟氨酸脱羧酶和氨基转移酶。其次，提出了研究以检查循环拉伸和剪切应力对血管SMC L-精氨酸/L-雌激素转运和代谢的更复杂，病理学相关的血液动力学刺激的影响。 第三，这些体外发现将应用于血管损伤的体内模型。 将使用良好表征的小鼠动脉损伤模型来研究实验，以研究L-精氨酸/L-雌雄同体转运和代谢的调节。 使用药理学和最终的转基因方法，该模型应有助于定义SMC阳离子氨基酸转运和代谢在体内血管重塑中的生物学作用。阐明调节对血管损伤反应的分子机制将为治疗干预提供新的合理目标。