Article

Enhanced postischemic functional recovery in CYP2J2 transgenic hearts involves mitochondrial ATP-sensitive K+ channels and p42/p44 MAPK pathway.

Division of Intramural Research, NIEHS/NIH, Research Triangle Park, NC 27709, USA.
Circulation Research (Impact Factor: 11.09). 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.

0 Followers
 · 
70 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Polyunsaturated fatty acids (PUFA) are oxidized by cytochrome P450 epoxygenases to PUFA epoxides which function as potent lipid mediators. The major metabolic pathways of PUFA epoxides are incorporation into phospholipids and hydrolysis to the corresponding PUFA diols by soluble epoxide hydrolase. Inhibitors of soluble epoxide hydrolase stabilize PUFA epoxides and potentiate their functional effects. The epoxyeicosatrienoic acids (EETs) synthesized from arachidonic acid produce vasodilation, stimulate angiogenesis, have anti-inflammatory actions, and protect the heart against ischemia-reperfusion injury. EETs produce these functional effects by activating receptor-mediated signaling pathways and ion channels. The epoxyeicosatetraenoic acids synthesized from eicosapentaenoic acid and epoxydocosapentaenoic acids synthesized from docosahexaenoic acid are potent inhibitors of cardiac arrhythmias. Epoxydocosapentaenoic acids also inhibit angiogenesis, decrease inflammatory and neuropathic pain, and reduce tumor metastasis. These findings indicate that a number of the beneficial functions of PUFA may be due to their conversion to PUFA epoxides. This article is part of a Special Issue entitled "Oxygenated metabolism of PUFA: analysis and biological relevance.
    Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids 08/2014; 1851(4). DOI:10.1016/j.bbalip.2014.07.020 · 4.50 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A specific behavioural response of Caenorhabditis elegans, the rapid increase of locomotion in response to anoxia/reoxygenation called the O2-ON response, has been used to model key aspects of ischemia/reperfusion injury. A genetic suppressor screen demonstrated a direct causal role of CYP-13A12 in this response and suggested that CYP-eicosanoids, which in mammals influence the contractility of cardiomyocytes and vascular smooth muscle cells, might function in C. elegans as specific regulators of the body muscle cell activity. Here we show that co-expression of CYP-13A12 with the NADPH-CYP-reductase EMB-8 in insect cells resulted in the reconstitution of an active microsomal monooxygenase system that metabolised EPA (eicosapentaenoic acid) and also AA (arachidonic acid) to specific sets of regioisomeric epoxy and hydroxy derivatives. Main products included 17,18-EEQ (epoxyeicosatetraenoic acid) from EPA and 14,15-EET (epoxyeicosatrienoic acid) from AA. Locomotion assays showed that the defective O2-ON response of C20-PUFA-deficient, Δ-12 and Δ-6 fatty acid desaturase mutants (fat-2 and fat-3, respectively) can be restored by feeding the nematodes AA or EPA, but not ETYA (eicosatetraynoic acid), a non-metabolisable AA-analogue. Already short-term incubation with 17,18-EEQ was sufficient to rescue the impaired locomotion of the fat-3 strain. The endogenous level of free 17,18-EEQ declined during anoxia and was rapidly restored in response to reoxygenation. Based on these results, we suggest that CYP-dependent eicosanoids such as 17,18-EEQ function as signalling molecules in the regulation of the O2-ON response in C. elegans. Remarkably, the exogenously administered 17,18-EEQ increased the locomotion activity already under normoxic conditions and was effective not only with C20-PUFA mutants but to a lesser extent also with wild-type worms.
    Biochemical Journal 08/2014; 464. DOI:10.1042/BJ20140848 · 4.78 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Over the last 20 years, it has become clear that cytochrome P450 (P450) enzymes generate a spectrum of bioactive lipid mediators from endogenous substrates. However, studies focused on the determining biologic activity of the P450 system have focused largely on the metabolites generated by one substrate (i.e., arachidonic acid). However, epoxides and diols derived from other endogenous substrates, such as linoleic acid, eicosapentaenoic acid, and docosahexaenoic acid, may be generated in higher concentrations and may potentially be of more physiologic relevance. Recent studies that used a combination of phenotyping and lipid array analyses revealed that rather than being inactive products, fatty acid diols play important roles in a number of biologic processes including inflammation, angiogenesis, and metabolic regulation. Moreover, inhibitors of the soluble epoxide hydrolase that increase epoxide but decrease diol levels have potential for the treatment of the metabolic syndrome.
    Pharmacological reviews 10/2014; 66(4):1106-1140. DOI:10.1124/pr.113.007781 · 18.55 Impact Factor

Full-text (3 Sources)

Download
26 Downloads
Available from
May 23, 2014