Anesthesiology Service, Veterans Affairs Medical Center, Mail Code: P3ANES, 3710 SW US Veterans Hospital Rd., Portland, OR 97239, USA.
Am J Physiol Heart Circ Physiol. 2010 Feb;298(2):H679-87. doi: 10.1152/ajpheart.00533.2009. Epub 2009 Dec 11.
Soluble epoxide hydrolase (sEH) metabolizes epoxyeicosatrienoic acids (EETs), primarily 14,15-EET. EETs are derived from arachidonic acid via P-450 epoxygenases and are cardioprotective. We tested the hypothesis that sEH deficiency and pharmacological inhibition elicit tolerance to ischemia via EET-mediated STAT3 signaling in vitro and in vivo. In addition, the relevance of single nucleotide polymorphisms (SNPs) of EPHX2 (the gene encoding sEH) on tolerance to oxygen and glucose deprivation and reoxygenation and glucose repletion (OGD/RGR) was assessed in male C57BL\6J (WT) or sEH knockout (sEHKO) cardiomyocytes by using transactivator of transcription (TAT)-mediated transduction with sEH mutant proteins. Cell death and hydrolase activity was lower in Arg287Gln EPHX2 mutants vs. nontransduced controls. Excess 14,15-EET and SEH inhibition did not improve cell survival in Arg287Gln mutants. In WT cells, the putative EET receptor antagonist, 14,15-EEZE, abolished the effect of 14,15-EET and sEH inhibition. Cotreatment with 14,15-EET and SEH inhibition did not provide increased protection. In vitro, STAT3 inhibition blocked 14,15-EET cytoprotection, but not the effect of SEH inhibition. However, STAT3 small interfering RNA (siRNA) abolished cytoprotection by 14,15-EET and sEH inhibition, but cells pretreated with JAK2 siRNA remained protected. In vivo, STAT3 inhibition abolished 14,15-EET-mediated infarct size reduction. In summary, the Arg287Gln mutation is associated with improved tolerance against ischemia in vitro, and inhibition of sEH preserves cardiomyocyte viability following OGD/RGR via an EET-dependent mechanism. In vivo and in vitro, 14,15-EET-mediated protection is mediated in part by STAT3.
可溶性环氧化物水解酶（sEH）代谢环氧二十碳三烯酸（EETs），主要是 14,15-EET。EETs 是从花生四烯酸通过 P-450 环氧化酶产生的，具有心脏保护作用。我们测试了 sEH 缺乏和药理学抑制通过 EET 介导的 STAT3 信号在体外和体内引起对缺血耐受的假说。此外，通过使用转录激活因子（TAT）介导的 sEH 突变蛋白转导，评估 EPHX2（编码 sEH 的基因）单核苷酸多态性（SNPs）对氧和葡萄糖剥夺及再氧合和葡萄糖再补充（OGD/RGR）的耐受性在雄性 C57BL\6J（WT）或 sEH 敲除（sEHKO）心肌细胞中的相关性。与非转导对照相比，Arg287Gln EPHX2 突变体中的细胞死亡和水解酶活性较低。过量的 14,15-EET 和 SEH 抑制不能改善 Arg287Gln 突变体中的细胞存活。在 WT 细胞中，假定的 EET 受体拮抗剂 14,15-EEZE 消除了 14,15-EET 和 sEH 抑制的作用。14,15-EET 和 SEH 抑制的联合治疗没有提供增加的保护。在体外，STAT3 抑制阻断了 14,15-EET 的细胞保护作用，但不阻断 SEH 抑制的作用。然而，STAT3 小干扰 RNA（siRNA）消除了 14,15-EET 和 sEH 抑制的细胞保护作用，但用 JAK2 siRNA 预处理的细胞仍受到保护。在体内，STAT3 抑制消除了 14,15-EET 介导的梗死面积减小。总之，Arg287Gln 突变与体外对缺血的耐受性提高有关，并且 OGD/RGR 后通过 EET 依赖性机制抑制 sEH 可保持心肌细胞活力。在体内和体外，14,15-EET 介导的保护部分通过 STAT3 介导。
