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: 6653343
• 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: 2002
• 资助国家: 美国
• 起止时间: 2002-09-01 至 2003-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6653343
• 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.

这是研究大鼠肾脏的血管和管状细胞中20-羟基羟基乙烯烯酸（20-HETE）合成的调节机制的建议。我们的研究已经确定，花生四烯酸（AA）的omega-羟基化产物20-Hete是在大鼠肾皮质和外部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种Hete具有有效的生物学活动，并提供了证据表明它有助于调节肾脏血管和管状功能，并控制动脉压的控制。包括AA在内的脂肪酸的omega-羟基化是由CYP4A家族的酶（包括4A1，4A2、4A3和4A8）催化的。我们的研究表明，尽管具有较高的同源性，但这些同工型表现出不同的催化特性，包括动力学参数，产品曲线和抑制剂敏感性的差异。我们假设大鼠CYP4A酶尽管共享非常高的序列同源性和共同的独特性，即，在欧米茄碳中羟on子的羟基苯二酚的羟基化形成20-Hete，但表现出不同的催化活性和底物的特异性，并且在不同的局部和不同的范围下，在不同的局部机构中，在不同的情况下，在不同的情况下，在不同的方面，在此不同，在不同的是，在此不同，在此不同，贡献了不同的机械级别，这些机构是造成的。催化活性和调节机制，从而在给定的组织中有明显的内源性水平。为了理解调节机制，在给定的组织中有明显的内源水平有助于内源性水平。为了理解这种重要类类肾合成的调节机制，拟议的研究旨在进一步识别这些同工型在生化和分子水平上相对于表达的催化活性和调节（AIM 1）（AIM 1）的差异（其次），其次是在细胞和肾功能中含义在Vitro（AIM 2）和AIM 2）和VIV（VIV）。这些CYP4A介导的20-HETE产生的细胞，生化和分子研究将增强我们对20-HETE生理功能的理解及其可能参与高血压和心血管疾病的发病机理。