The CYP4A Isoforms hydroxylate epoxyeicosatrienoic acids to form high affinity peroxisome proliferator-activated receptor ligands
The CYP4A Isoforms hydroxylate epoxyeicosatrienoic acids to form high affinity peroxisome proliferator-activated receptor ligands
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DOI：
10.1074/jbc.m201575200
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发表时间：
2002-09-20
影响因子：
4.8
通讯作者：
Capdevila, JH
中科院分区：
文献类型：
--
作者：
Cowart, LA;Wei, SZ;Capdevila, JH
CYP2C和CYP4A基因亚家族的细胞色素P450分别将花生四烯酸代谢为5,6-,8,9-,11,12-和14,15-环氧二碳四烯酸（EETs）和19-和20-羟基二碳四烯酸（HETEs）。大量的功能研究表明，作为离子通道活性的介质和血管张力和全身血压的调节剂，eet和HETEs表现出强大的、往往相反的生物活性。8、9-、11、12-和14、15- eet与大鼠CYP4A微体和纯化型异构体孵育，导致nadph依赖于相应的19-和20-羟基化eet的快速代谢。与花生四烯酸和月桂酸的反应速率和催化效率的比较表明，eet是迄今为止描述的大鼠CYP4A亚型的最佳内源底物之一。CYP4A1偏爱8,9- eet，而CYP4A2、CYP4A3和CYP4A8偏爱11,12- eet。一般来说，氧化环越靠近羧酸官能团，EET的代谢率越高，EET -碳的区域特异性越低。对人过氧化物酶体增殖体激活受体α配体结合区域的顺式parinaric酸置换分析表明，omega-羟基化的14,15- eet与该受体具有高亲和力（K-i = 3 +/- 1 nM）。此外，在1mum时，14,15- eet的ω -醇或8,9-和11,12- eet的ω -醇的1:4混合物在瞬时转染试验中激活了人和小鼠过氧化物酶体增殖激活受体- α，表明它们作为这些孤儿核受体的内源性配体的作用。
Cytochromes P450 of the CYP2C and CYP4A gene subfamilies metabolize arachidonic acid to 5,6-, 8,9-, 11,12-, and 14,15-epoxyeicosatrienoic acids (EETs) and to 19- and 20-hydroxyeicosatetraenoic acids (HETEs), respectively. Abundant functional studies indicate that EETs and HETEs display powerful and often opposing biological activities as mediators of ion channel activity and regulators of vascular tone and systemic blood pressures. Incubation of 8,9-,11,12-, and 14,15-EETs with microsomal and purified forms of rat CYP4A isoforms led to rapid NADPH-dependent metabolism to the corresponding 19- and 20-hydroxylated EETs. Comparisons of reaction rates and catalytic efficiency with those of arachidonic and lauric acids showed that EETs are one of the best endogenous substrates so far described for rat CYP4A isoforms. CYP4A1 exhibited a preference for 8,9-EET, whereas CYP4A2, CYP4A3, and CYP4A8 preferred 11,12-EET. In general, the closer the oxido ring is to the carboxylic acid functionality, the higher the rate of EET metabolism and the lower the regiospecificity for the EET omega-carbon. Analysis of cis-parinaric acid displacement from the ligand-binding domain of the human peroxisome proliferator-activated receptor-alpha showed that omega-hydroxylated 14,15-EET bound to this receptor with high affinity (K-i = 3 +/- 1 nM). Moreover, at 1 muM, the omega-alcohol of 14,15-EET or a 1:4 mixture of the omega-alcohols of 8,9- and 11,12-EETs activated human and mouse peroxisome proliferator-activated receptor-alpha in transient transfection assays, suggesting a role for them as endogenous ligands for these orphan nuclear receptors.