Division of Intramural Research, National Institute for Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA.
FASEB J. 2011 Oct;25(10):3436-47. doi: 10.1096/fj.11-188300. Epub 2011 Jun 22.
Cytochrome P450 (CYP) epoxygenases CYP2C8 and CYP2J2 generate epoxyeicosatrienoic acids (EETs) from arachidonic acid. Mice with expression of CYP2J2 in cardiomyocytes (αMHC-CYP2J2 Tr) or treated with synthetic EETs have increased functional recovery after ischemia/reperfusion (I/R); however, no studies have examined the role of cardiomyocyte- vs. endothelial-derived EETs or compared the effects of different CYP epoxygenase isoforms in the ischemic heart. We generated transgenic mice with increased endothelial EET biosynthesis (Tie2-CYP2C8 Tr and Tie2-CYP2J2 Tr) or EET hydrolysis (Tie2-sEH Tr). Compared to wild-type (WT), αMHC-CYP2J2 Tr hearts showed increased recovery of left ventricular developed pressure (LVDP) and decreased infarct size after I/R. In contrast, LVDP recovery and infarct size were unchanged in Tie2-CYP2J2 Tr and Tie2-sEH Tr hearts. Surprisingly, compared to WT, Tie2-CYP2C8 Tr hearts had significantly reduced LVDP recovery (from 21 to 14%) and increased infarct size after I/R (from 51 to 61%). Tie2-CYP2C8 Tr hearts also exhibited increased reactive oxygen species (ROS) generation, dihydroxyoctadecenoic acid (DiHOME) formation, and coronary resistance after I/R. ROS scavengers and CYP2C8 inhibition reversed the detrimental effects of CYP2C8 expression in Tie2-CYP2C8 Tr hearts. Treatment of WT hearts with 250 nM 9,10-DiHOME decreased LVDP recovery compared to vehicle (16 vs. 31%, respectively) and increased coronary resistance after I/R. These data demonstrate that increased ROS generation and enhanced DiHOME synthesis by endothelial CYP2C8 impair functional recovery and mask the beneficial effects of increased EET production following I/R.
细胞色素 P450（CYP）环氧合酶 CYP2C8 和 CYP2J2 可从花生四烯酸生成环氧二十碳三烯酸（EETs）。在心肌细胞中表达 CYP2J2 的小鼠（αMHC-CYP2J2 Tr）或用合成 EET 治疗的小鼠在缺血/再灌注（I/R）后功能恢复增加；然而，尚无研究检查心肌细胞与内皮细胞衍生的 EETs 的作用或比较不同 CYP 环氧合酶同工酶在缺血心脏中的作用。我们生成了内皮细胞 EET 生物合成增加的转基因小鼠（Tie2-CYP2C8 Tr 和 Tie2-CYP2J2 Tr）或 EET 水解增加的转基因小鼠（Tie2-sEH Tr）。与野生型（WT）相比，αMHC-CYP2J2 Tr 心脏在 I/R 后左心室发展压（LVDP）的恢复增加，梗死面积减小。相比之下，Tie2-CYP2J2 Tr 和 Tie2-sEH Tr 心脏的 LVDP 恢复和梗死面积没有变化。令人惊讶的是，与 WT 相比，Tie2-CYP2C8 Tr 心脏的 LVDP 恢复明显减少（从 21%降至 14%），I/R 后梗死面积增加（从 51%增至 61%）。Tie2-CYP2C8 Tr 心脏也表现出 I/R 后活性氧（ROS）生成、二羟十八碳烯酸（DiHOME）形成和冠状动脉阻力增加。ROS 清除剂和 CYP2C8 抑制剂逆转了 Tie2-CYP2C8 Tr 心脏中 CYP2C8 表达的有害影响。与载体相比，WT 心脏用 250 nM 9,10-DiHOME 治疗后 LVDP 恢复降低（分别为 16%和 31%），I/R 后冠状动脉阻力增加。这些数据表明，内皮细胞 CYP2C8 增加的 ROS 生成和增强的 DiHOME 合成会损害功能恢复，并掩盖 I/R 后增加的 EET 产生的有益作用。
