FUNCTION AND REGULATION OF CYTOCHROME P450 4A ISOFORMS

细胞色素 P450 4A 异构体的功能和调节

• 批准号: 6578854
• 负责人: Michal Laniado Schwartzman
• 金额: $ 31.48万
• 依托单位: NEW YORK MEDICAL COLLEGE
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-11-01 至 2002-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6578854
• 关键词: cytochrome P450; eicosanoid metabolism; eicosanoids; enzyme activity; enzyme mechanism; fatty acid metabolism; gas chromatography mass spectrometry; gene expression; hydroxylation; hypertension; isolation perfusion; isozymes; kidney metabolism; laboratory rat; protein isoforms; protein localization; renal tubular transport; spontaneous hypertensive rat

This is a proposal to investigate the mechanisms underlying the regulation of 20-hydroxyeicosatetraenoic acid (20-HETE) synthesis in vascular and tubular cells of the rat kidney. Our studies have established that 20- HETE, the omega-hydroxylation product of arachidonic acid (AA), is the principal AA metabolite formed in tubular and vascular structures of the rat renal cortex and outer medulla. We and others have demonstrated that 20 HETE is endowed with potent biological activities and have provided evidence that it contributes to the regulation of renal vascular and tubular functions and to the control of arterial pressures. The omega- hydroxylation of fatty acids, including AA, is catalyzed by enzymes of the CYP4A family including 4A1, 4A2, 4A3 and 4A8. Our studies indicated that despite the high homology, these isoforms display distinct catalytic properties including differences in kinetic parameters, product profile and inhibitor sensitivity. We hypothesize that the rat CYP4A enzymes, although sharing very high sequence homology and a common unique, i.e., hydroxylation of arachidonic acid at the omega carbon to form 20-HETE, exhibit different catalytic activities and substrate specificities, and display distinct patterns of localized and ,most likely, are under different regulatory mechanisms, thereby, distinct contributing to the endogenous level of 20-HETE, exhibit different catalytic activities and regulatory mechanisms, thereby distinctively contributing to the endogenous level of 20-HETE in a given tissue. To understand the regulatory mechanisms, thereby, distinctively contributing to the endogenous level of 20-HETE in a given tissue. To understand the regulatory mechanisms underlying the renal synthesis of this important eicosanoid, the proposed studies are designed to further identify differences among these isoforms at the biochemical and molecular levels with respect to catalytic activity and regulation of expression (Aim 1) and, secondly, to implicate such differences in terms of cell and renal function in vitro (Aim 2) and in vivo (Aim 3). These cellular, biochemical, and molecular studies of CYP4A-mediated, 20-HETE production will increase our understanding of the physiological function of 20-HETE and its possible involvement in the pathogenesis of hypertension and cardiovascular diseases.

本提案旨在研究大鼠肾脏血管和肾小管细胞中 20-羟基二十碳四烯酸 (20-HETE) 合成的调节机制。我们的研究已证实，20-HETE（花生四烯酸 (AA) 的 omega-羟基化产物）是在大鼠肾皮质和外髓质的管状和血管结构中形成的主要 AA 代谢物。我们和其他人已经证明 20 HETE 具有强大的生物活性，并提供证据表明它有助于调节肾血管和肾小管功能以及控制动脉压。脂肪酸（包括 AA）的 omega-羟基化由 CYP4A 家族的酶（包括 4A1、4A2、4A3 和 4A8）催化。我们的研究表明，尽管具有高度同源性，但这些亚型表现出不同的催化特性，包括动力学参数、产物概况和抑制剂敏感性的差异。我们假设大鼠 CYP4A 酶虽然具有非常高的序列同源性和共同的独特性，即花生四烯酸在 omega 碳处羟基化形成 20-HETE，但表现出不同的催化活性和底物特异性，并显示出不同的局部和底物模式。最有可能的是，它们处于不同的调节机制下，因此，对 20-HETE 的内源水平有不同的贡献，表现出不同的催化活性和调节机制，从而对 20-HETE 的内源水平有不同的贡献给定组织中 20-HETE 的内源水平。了解调节机制，从而对特定组织中 20-HETE 的内源水平做出独特贡献。为了了解这种重要的类二十烷酸的肾脏合成的调节机制，拟议的研究旨在进一步确定这些异构体在生化和分子水平上在催化活性和表达调节方面的差异（目标 1），其次，暗示了体外（目标 2）和体内（目标 3）细胞和肾功能方面的这种差异。这些对 CYP4A 介导的 20-HETE 产生的细胞、生化和分子研究将增加我们对 20-HETE 生理功能及其可能参与高血压和心血管疾病发病机制的了解。