Zeldin D C, Foley J, Ma J, Boyle J E, Pascual J M, Moomaw C R, Tomer K B, Steenbergen C, Wu S
Laboratory of Pulmonary Pathobiology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA.
Mol Pharmacol. 1996 Nov;50(5):1111-7.
Cytochrome P450 (P450) monooxygenases catalyze the epoxidation of arachidonic acid to form epoxyeicosatrienoic acids, which modulate bronchial smooth muscle tone and airway transepithelial ion transport. We recently described a new human P450 arachidonic acid epoxygenase (CYP2J2) and the corresponding rat homologue (CYP2J3). Northern analysis of lung RNA using CYP2J cDNA probes demonstrated that CYP2J2 and CYP2J3 mRNAs were expressed in the lung. Immunoblotting of microsomal fractions prepared from human and rat lungs using a polyclonal antibody raised against recombinant human CYP2J2 revealed a single 56-kDa band confirming abundant pulmonary CYP2J2 and CYP2J3 protein expression. Immunohistochemical analysis of formalin-fixed paraffin-embedded human and rat lung sections using the anti-human CYP2J2 IgG and avidin/biotin/peroxidase detection showed that CYP2J proteins were primarily expressed in ciliated epithelial cells lining the airway. Prominent staining was also noted in nonciliated airway epithelial cells, bronchial and pulmonary vascular smooth muscle cells, pulmonary vascular endothelium, and alveolar macrophages, whereas less intense staining was noted in alveolar epithelial cells. Endogenous epoxyeicosatrienoic acids were detected in both human and rat lung using gas chromatography/mass spectrometry, thus providing direct evidence for the in vivo human and rat pulmonary P450 metabolism of arachidonic acid. Based on these data, we conclude that CYP2J2 and CYP2J3 are abundant pulmonary arachidonic acid epoxygenases and that CYP2J products, the epoxyeicosatrienoic acids, are endogenous constituents of human and rat lung. In addition to known effects on airway smooth muscle tone and transepithelial electrolyte transport, the localization of CYP2J proteins to vascular smooth muscle and endothelium suggests that epoxyeicosatrienoic acids may also be involved in the modulation of pulmonary vascular tone.
细胞色素P450（P450）单加氧酶催化花生四烯酸环氧化形成环氧二十碳三烯酸，后者可调节支气管平滑肌张力和气道跨上皮离子转运。我们最近描述了一种新的人类P450花生四烯酸环氧化酶（CYP2J2）及其相应的大鼠同源物（CYP2J3）。使用CYP2J cDNA探针进行的肺RNA的Northern分析表明，CYP2J2和CYP2J3 mRNA在肺中表达。使用针对重组人CYP2J2产生的多克隆抗体对人肺和大鼠肺制备的微粒体组分进行免疫印迹，显示出一条单一的56 kDa条带，证实肺中CYP2J2和CYP2J3蛋白表达丰富。使用抗人CYP2J2 IgG和抗生物素蛋白/生物素/过氧化物酶检测对福尔马林固定石蜡包埋的人肺和大鼠肺切片进行免疫组织化学分析，结果显示CYP2J蛋白主要表达于气道内衬的纤毛上皮细胞中。在非纤毛气道上皮细胞、支气管和肺血管平滑肌细胞、肺血管内皮细胞和肺泡巨噬细胞中也观察到明显的染色，而在肺泡上皮细胞中染色较弱。使用气相色谱/质谱法在人肺和大鼠肺中均检测到内源性环氧二十碳三烯酸，从而为花生四烯酸在体内的人肺和大鼠肺P450代谢提供了直接证据。基于这些数据，我们得出结论，CYP2J2和CYP2J3是肺中丰富的花生四烯酸环氧化酶，并且CYP2J产物环氧二十碳三烯酸是人和大鼠肺的内源性成分。除了对气道平滑肌张力和跨上皮电解质转运的已知作用外，CYP2J蛋白在血管平滑肌和内皮中的定位表明环氧二十碳三烯酸也可能参与肺血管张力的调节。
