Cytochrome P450 Eicosanoids and Myocardial Injury

最近的一些研究表明，低氧诱导细胞色素P450环氧合酶的表达，尤其是 在几种细胞类型中，细胞色素P4502C9和EET的产生。我们令人兴奋的初步结果表明，有几行 CYP来源的EET的重要作用和可能的信号通路在诱导中作用的证据 心脏保护。在细胞中，低氧诱导EETs的产生。初步数据显示， 外源性EETs增强表皮生长因子的活性(磷酸化) 受体(EGFR)。此外，根据检测，EETs增加了缺氧诱导因子-1(一个亚单位，HIF-1a) 通过西方在核部分的斑点。这些结果提示了几条重要的信号通路。 在心脏保护方面。例如，EET可以反式激活EGFR。内毒素对HIF-1a的激活作用 提示低氧诱导的CYP来源的EETs可能存在正反馈，进而EETs上调 HIF-1a可起到心脏保护作用。我们研究的其他证据表明， 可能参与CYP环氧合酶和EET诱导的心脏保护包括活性氧 ROS、蛋白激酶C-epsilon、PI3K/Akt信号通路、糖原合成酶-β(GSK3- 以及肌膜和线粒体！ATP调节的钾通道与线粒体通透性 过渡孔(MPTP)。具体来说，我们将测试以下目标： 特定目的1：证实缺氧是否上调细胞色素P450环氧合酶和EETs 心肌细胞。我们将确定低氧是否诱导CYP环氧合酶(亚型)的表达。 和EETs(异构体)的生产。我们将检测低氧心肌细胞中的CYP环氧合酶和 缺血的心脏组织。 具体目标2：使用药物和药物演示EET在心肌细胞中的功能 外源内源内毒素。我们将测试外源EET(11，12-和14，15-EET)对提高活性的影响 EGFRandHIF-1a。 具体目标3：阐明导致心脏保护的EET信号通路。我们将调查 EET对EGFR的反式激活及ROS在激活EGFR中的作用。此外，我们将调查 EET激活EGFR的下游信号通路，包括PKC/Akt/TK、p38或ERK1/2 小路。我们还将研究外源性EET是否激活HIF-1a，以及是否通过 激活ROS和EGFR。因此，在正在进行的研究计划中，我们将研究机械作用 EETs在心肌细胞(HL-1细胞、大鼠心肌细胞)和基因敲除等细胞系统中的表达 或者过度表达老鼠。

Several recent studies demonstrated that hypoxia induces the expression of CYP epoxygenases, particularly CYP2C9, and EET production in several cell types. Our exciting preliminary results suggest several lines of evidence for important roles of CYP-derived EETs and possible signajing pathways in eliciting cardioprotection. In cells, hypoxia induces the production of EETs. Preliminary data suggest that exogenously administered EETs increased the activity (phosphorylation) of Epidermal Growth Factor Receptor (EGFR). Furthermore, EETs increased hypoxia-inducible factor-1 (a subunit, HIF-1a), as detected by Western blots in the nuclear fraction. These results suggest several signaling pathways that are important in cardioprotection. For example, EETs may transactivate the EGFR. The activation of HIF-1a by EETs indicates a possible positive feedback of hypoxia-induced CYP-derived EETs, and in turn EETs upregulate HIF-1a which leads to cardioprotection. Other evidence from our studies which suggest mechanisms that might be involved in CYP epoxygenase and EET-induced cardioprotection include reactive oxygen species (ROS), Protein Kinase C-epsilon, the PI3K/Akt signaling pathway, glycogen synthase kinase-beta (GSK3- beta) and the sarcolemmal and mitochondria! ATP-regulated K channels and the mitochondrial permeability transition pore (MPTP). Specifically, we will test the following aims: Specific Aim 1: Demonstrate whether CYP epoxygenases and EETs are upregulated by hypoxia in cardiomyocytes. We will determine whether hypoxia induces expression of CYP epoxygenases (isoforms) and production of EETs (isomers). We will detect CYP epoxygenases in hypoxic cardiomyocytes and ischemic heart tissue. Specific Aim 2: Demonstrate the functions of EETs in cardiomyocytes using pharmacological agents and exogenous EETs. We will test the effects of exogenous EETs (11,12- and 14,15-EET) to increase the activity of EGFRandHIF-1a. Specific Aim 3: Elucidate the EET signaling pathways that lead to cardioprotection. We will investigate the transactivation of EGFR by EETs and the role of ROS in activating EGFR. Furthermore, we will investigate the down stream signaling pathways of EGFR activation by EETs, including the PKC/Akt/TK, p38, or ERK1/2 pathways. We will also investigate whether exogenous EETs activate HIF-1a, and whether it is through the activation of ROS and EGFR. Thus, in the ongoing research plan, we will investigate the mechanistic actions of EETs in cellular systems such as cardiomyocytes (HL-1 cells, rat cardiomyocytes) and in gene knockout or overexpressing mice.