Article

Enhanced Postischemic Functional Recovery in CYP2J2 Transgenic Hearts Involves Mitochondrial ATP-Sensitive K+ Channels and p42/p44 MAPK Pathway

Duke University, Durham, North Carolina, United States
Circulation Research (Impact Factor: 11.02). 10/2004; 95(5):506-14. DOI: 10.1161/01.RES.0000139436.89654.c8
Source: PubMed

ABSTRACT

Human CYP2J2 is abundant in heart and active in the biosynthesis of epoxyeicosatrienoic acids (EETs); however, the functional role of this P450 and its eicosanoid products in the heart remains unknown. Transgenic mice with cardiomyocyte-specific overexpression of CYP2J2 were generated. CYP2J2 transgenic (Tr) mice have normal heart anatomy and basal contractile function. CYP2J2 Tr hearts have improved recovery of left ventricular developed pressure (LVDP) compared with wild-type (WT) hearts after 20 minutes ischemia and 40 minutes reperfusion. Perfusion with the selective P450 epoxygenase inhibitor N-methylsulphonyl-6-(2-proparglyloxyphenyl)hexanamide (MS-PPOH) for 20 minutes before ischemia results in reduced postischemic LVDP recovery in WT hearts and abolishes the improved postischemic LVDP recovery in CYP2J2 Tr hearts. Perfusion with the ATP-sensitive K(+) channel (K(ATP)) inhibitor glibenclamide (GLIB) or the mitochondrial K(ATP) (mitoK(ATP)) inhibitor 5-hydroxydecanoate (5-HD) for 20 minutes before ischemia abolishes the cardioprotective effects of CYP2J2 overexpression. Flavoprotein fluorescence, a marker of mitoK(ATP) activity, is higher in cardiomyocytes from CYP2J2 Tr versus WT mice. Moreover, CYP2J2-derived EETs (1 to 5 micromol/L) increase flavoprotein fluorescence in WT cardiomyocytes. CYP2J2 Tr mice exhibit increased expression of phospho-p42/p44 mitogen-activated protein kinase (MAPK) after ischemia, and addition of the p42/p44 MAPK kinase (MEK) inhibitor PD98059 during reperfusion abolishes the cardioprotective effects of CYP2J2 overexpression. Together, these data suggest that CYP2J2-derived metabolites are cardioprotective after ischemia, and the mechanism for this cardioprotection involves activation of mitoK(ATP) and p42/p44 MAPK.

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    • "Nithipatikom et al. [27] found that exogenous EETs produced a marked reduction in infarct size in dogs. Another study reported that the expression of CYP2J2 in cardiomyocytes led to improved functional recovery and reduced infarct size after ischemia [28]. EETs were reported to have aided in the preservation of mitochondrial integrity and membrane potential during I/R [29]. "
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    ABSTRACT: 14,15-Epoxyeicosatrienoic acids (14,15-EETs) generated from arachidonic acid by cytochrome P450 epoxygenases have beneficial effects in certain cardiovascular diseases, and increased 14,15-EET levels protect the cardiovascular system. 14,15-EETs are rapidly hydrolyzed by soluble epoxide hydrolase (sEH) to the corresponding 14,15-dihydroxyeicosatrienoic acids (14,15-DHETs), which are generally less biologically active but more stable metabolite. A functionally relevant polymorphism of the CYP2J2 gene is independently associated with an increased risk of coronary heart disease (CHD), and the major CYP2J2 product is 14,15-EETs. 14,15-DHETs can be considered a relevant marker of CYP2J2 activity. Therefore, the aim of the present study was to evaluate the plasma 14,15-DHET levels to reflect the 14,15-EET levels in an indirectly way in patients with CHD, and to highlight the growing body of evidence that 14,15-EETs also play a role in anti-inflammatory and lipid-regulating effects in patients with CHD. This was achieved by investigating the relationship between 14,15-DHETs and high-sensitivity C-reactive protein (hs-CRP) and blood lipoproteins. Samples of peripheral venous blood were drawn from 60 patients with CHD and 60 healthy controls. A 14,15-DHET enzyme-linked immunosorbent assay kit (14,15-DHET ELISA kit) was used to measure the plasma 14,15-DHET levels. Hs-CRP, total cholesterol, triglyceride, high-density lipoprotein cholesterol, and low-density lipoprotein-cholesterol levels were measured. 14,15-DHET levels (2.53 +/- 1.60 ng/mL) were significantly higher in patients with CHD as compared with those of the healthy controls (1.65 +/- 1.54 ng/mL, P < 0.05). There was a significant positive correlation between 14,15-DHETs and hs-CRP levels (R = 0.286, P = 0.027). However, there was no significant correlation between 14,15-DHETs and blood lipoproteins (all, P > 0.05). Increased plasma 14,15-DHET levels reflect the decreased of 14,15-EET levels in an indirectly way . Indicated that decreased plasma 14,15-EET levels might be involved in the inflammatory reaction process in atherosclerosis.
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    • "However, a human heart model remains elusive and testing relies on animal-model, especially dog, cell systems or recombinant enzymes. Much of CYP2J2's activity has been assessed in such models as Escherichia coli-expressed or Baculovirus-infected insect cell–expressed enzyme (Supersomes) (Lafite et al., 2007), human liver microsomes (Lee et al., 2012), or in humanized animal models that overexpress the enzyme in cardiac tissue (Seubert et al., 2004; Deng et al., 2011). "
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    ABSTRACT: Cytochrome P450 2J2 (CYP2J2) plays a significant role in the epoxidation of arachidonic acid to important signaling molecules in cardiovascular events. CYP2J2 also contributes to drug metabolism and is responsible for the intestinal clearance of ebastine. However, the interaction between arachidonic acid metabolism and drug metabolism in cardiac tissue, the main expression site of CYP2J2, has not been examined. Here we investigate an adult-derived human primary cardiac cell line as a suitable model to study metabolic drug interactions (inhibition and induction) of CYP2J2 in cardiac tissue. The primary human cardiomyocyte cell line demonstrated similar mRNA-expression profiles of CYP-enzymes to adult human ventricular tissue. CYP2J2 was the dominant isozyme with minor contributions from CYP2D6 and CYP2E1. Both terfenadine and astemizole oxidation were observed in this cell line whereas midazolam was not metabolized suggesting lack of CYP3A activity. Compared to recombinant CYP2J2, terfenadine was hydroxylated in cardiomyocytes at a similar Km value of 1.5 μM. The Vmax of terfenadine hydroxylation in recombinant enzyme was found to be 29.4 pmol/pmol P450/min and in the cells 6.0 pmol/pmol P450/min. CYP2J2 activity in the cell line was inhibited by danazol, astemizole and ketoconazole in sub-micromolar range, but also by xenobiotics known to cause cardiac adverse effects. Of the 14 compounds tested for CYP2J2 induction, only rosiglitazone increased mRNA expression by 1.8 fold. This cell model can be a useful in vitro model to investigate the role of CYP2J2 mediated drug metabolism, arachidonic acid metabolism and their association to drug induced cardiotoxicity.
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    • "Similarly, EETs have been shown to activate ERK and p38 MAPKs in ECs (Wang et al., 2005). Moreover, it has been demonstrated that CYP2J2-derived metabolites are cardioprotective subsequent to ischemia by a mechanism that involves p42/p44 MAPK activation (Seubert et al., 2004). "
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    ABSTRACT: Abstract A plethora of studies have demonstrated the expression of cytochrome P450 (CYP) and soluble epoxide hydrolase (sEH) enzymes in the heart and other cardiovascular tissues. In addition, the expression of these enzymes is altered during several cardiovascular diseases (CVDs), including cardiac hypertrophy (CH). The alteration in CYP and sEH expression results in derailed CYP-mediated arachidonic acid (AA) metabolism. In animal models of CH, it has been reported that there is an increase in 20-hydroxyeicosatetraenoic acid (20-HETE) and a decrease in epoxyeicosatrienoic acids (EETs). Further, inhibiting 20-HETE production by CYP ω-hydroxylase inhibitors and increasing EET stability by sEH inhibitors have been proven to protect against CH as well as other CVDs. Therefore, CYP-mediated AA metabolites 20-HETE and EETs are potential key players in the pathogenesis of CH. Some studies have investigated the molecular mechanisms by which these metabolites mediate their effects on cardiomyocytes and vasculature leading to pathological CH. Activation of several intracellular signaling cascades, such as nuclear factor of activated T cells, nuclear factor kappa B, mitogen-activated protein kinases, Rho-kinases, Gp130/signal transducer and activator of transcription, extracellular matrix degradation, apoptotic cascades, inflammatory cytokines, and oxidative stress, has been linked to the pathogenesis of CH. In this review, we discuss how 20-HETE and EETs can affect these signaling pathways to result in, or protect from, CH, respectively. However, further understanding of these metabolites and their effects on intracellular cascades will be required to assess their potential translation to therapeutic approaches for the prevention and/or treatment of CH and heart failure.
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