Eicosanoid formation by a cytochrome P450 isoform expressed in the pharynx of Caenorhabditis elegans
Eicosanoid formation by a cytochrome P450 isoform expressed in the pharynx of Caenorhabditis elegans
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DOI：
10.1042/bj20101942
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发表时间：
2011-05-01
影响因子：
4.1
通讯作者：
Menzel, Ralph
中科院分区：
文献类型：
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作者：
Kosel, Mandy;Wild, Waltraud;Menzel, Ralph
秀丽隐杆线虫含有多个 CYP（细胞色素 P450）基因，这些基因与哺乳动物 CYP 亚型同源，对于产生生理活性 AA（花生四烯酸）代谢物非常重要。我们测试了以下假设：哺乳动物和线虫可能具有相似的 CYP 依赖性类二十烷酸形成和作用的基本机制。我们重点关注 CYP33E2，它是一种与人类 AA 环氧合酶 CYP2C8 和 CYP2J2 相关的亚型。昆虫细胞中 CYP33E2 与人 NADPH CYP 还原酶的共表达导致活性微粒体单加氧酶系统的重建，该系统代谢 EPA（二十碳五烯酸），并且以较低的活性将 AA 代谢为特定组的区域异构环氧和羟基衍生物。主要产品包括来自EPA的17,18-环氧二十碳四烯酸和来自AA的19-羟基二十碳四烯酸。使用携带 pCYP33E2::GFP 报告基因构建体的线虫，我们发现 CYP33E2 仅在咽部表达，主要位于边缘细胞中。 RNAi（RNA 干扰）介导的 CYP33E2 表达沉默以及哺乳动物 AA 代谢 CYP 酶抑制剂的治疗，显着降低了成年线虫的咽泵频率。这些结果表明，EPA 和 AA 是有效的 CYP33E2 底物，并表明 CYP-二十烷酸影响哺乳动物心肌细胞和血管平滑肌细胞的收缩性，可能在线虫中作为咽泵活动的调节剂发挥作用。
Caenorhabditis elegans harbours several CYP (cytochrome P450) genes that are homologous with mammalian CYP isoforms important to the production of physiologically active AA (arachidonic acid) metabolites. We tested the hypothesis that mammals and C. elegans may share similar basic mechanisms of CYP-dependent eicosanoid formation and action. We focused on CYP33E2, an isoform related to the human AA-epoxygenases CYP2C8 and CYP2J2. Co-expression of CYP33E2 with the human NADPH CYP reductase in insect cells resulted in the reconstitution of an active microsomal mono-oxygenase system that metabolized EPA (eicosapentaenoic acid) and, with lower activity, also AA to specific sets of regioisomeric epoxy- and hydroxy-derivatives. The main products included 17,18-epoxyeicosatetraenoic acid from EPA and 19-hydroxyeicosatetraenoic acid from AA. Using nematode worms carrying a pCYP33E2::GFP reporter construct, we found that CYP33E2 is exclusively expressed in the pharynx, where it is predominantly localized in the marginal cells. RNAi (RNA interference)-mediated CYP33E2 expression silencing as well as treatments with inhibitors of mammalian AA-metabolizing CYP enzymes, significantly reduced the pharyngeal pumping frequency of adult C. elegans. These results demonstrate that EPA and AA are efficient CYP33E2 substrates and suggest that CYP-eicosanoids, influencing in mammals the contractility of cardiomyocytes and vascular smooth muscle cells, may function in C. elegans as regulators of the pharyngeal pumping activity.