AIM:Cytochrome P450 epoxygenase 2J2 and epoxyeicosatrienoic acids ( EETs) are known to protect against cardiac hypertrophy and heart failure, which involve activation of 5′-AMP-activated protein kinase ( AMPK) and Akt.Although the functional roles of AMPK and Akt are well established , the significance of crosstalk between them in the development of cardiac hypertrophy and anti -hy-pertrophy of CYP2J2 and EETs remains unclear .Here, we investigated whether CYP 2J2 and its metabolites EETs protected against cardiac hypertrophy by activating AMPKα2 and Akt1.Moreover, we tested whether EETs enhanced crosstalk between AMPKα2 and phosphorylated Akt1 ( p-Akt1), and stimulated the nuclear translocation of p-Akt1, to exert their anti-hypertrophic effects. METHODS:The recombinant rAAV9 vector was coupled to CYP2J2 and the rAAV9-CYP2J2 construct was injected into the caudal vein of AMPKα2-/-and littermate control mice .AMPKα2 -/-and littermate control mice that overexpressed CYP 2J2 in heart were treated with angiotensin II (Ang II) for 2 weeks.Hemodynamic and cardiac functions were also evaluated after 14 days of infusion with Ang II or saline.RESULTS:Interestingly, the overexpression of CYP2J2 suppressed cardiac hypertrophy , including decreased heart size, cross sectional area of cardiomyocytes , markers of cardiac hypertrophy [ brain natriuretic peptide ( BNP) ,β-myosin heavy chain (β-MHC) and skeletal muscle α-actin (ACTA1)] and increased levels of atrial natriuretic peptide (ANP) in the heart tissue and plasma of wild-type mice but not AMPKα2 -/-mice.Measurement of left ventricular ejection fraction and fractional shortening showed that CYP2J2 overexpression prevented Ang II-induced ventricular systolic dysfunction in mice .Moreover, an Ang II-induced reduction in cardiac function, demonstrated by decreased dp/dtmax and dp/dtmin, was prevented by overexpression of CYP2J2.Mechanistically, the CYP2J2 metabolites 11,12-EET activated AMPKα2 to induce the nuclear translocation of p-Akt1, which increased production of ANP and thereby inhibited the development of cardiac hypertrophy .Furthermore , by co-immunoprecipitation analysis , we found that full-length Akt1 and an Akt1 fragment containing amino acids 150-408, which constitute the protein kinase domain , but not other frag-ments of Akt1, bind to the AMPKγ1 subunit.AMPKα2β2γ1 and p-Akt1 interact through the direct binding of the AMPKγ1 subunit to the Akt1 protein kinase domain.This interaction was enhanced by 11,12-EET.CONCLUSION:Our studies reveal a novel mechanism in which CYP2J2 and EETs enhanced Akt1 nuclear translocation through interaction with AMPKα2β2γ1 and protect against cardiac hy-pertrophy and suggest that overexpression of CYP 2J2 might have clinical potential to suppress cardiac hypertrophy and heart failure .

BACKGROUND:Cytochrome P450 ( CYP) epoxygenases metabolize arachidonic acids ( AA) to form epoxyeicosatrienoic acids
(EETs), which exert beneficial roles in the treatment of cardiovascular diseases , but little is known about its role on adventitial remo-deling.METHODS:We used C57BL/6J mice in vivo and primary rat adventitial fibroblasts ( AFs) in vitro treated with angiotensin II (Ang II) to investigate the effects of CYP2J2 gene delivery and exogenous EETs administration on adventitial remodeling .RESULTS:CYP/sEH system was found to exist in human adventitia , and involved in adventitial remodeling process .Exogenous EETs administra-tion significantly inhibited Ang II-induced AFs activation , characterized by differentiation , proliferation, migration, and collagen syn-thesis.These protective effects were partially reversed by PPARγantagonist GW9662 pretreatment or SOCS3 siRNA transfection.EETs suppressed Ang II-induced IκBαphosphorylation , subsequent NF-κB nuclear translocation via PPARγdependent signaling pathway in AFs.Additionally, EETs reduced Ang II-induced JAK2, STAT3 phosphorylation and subsequent phosphor-STAT3 nuclear transloca-tion, which were mediated by SOCS3 induction but independent of PPARγactivation.Furthermore, rAAV-CYP2J2 gene delivery re-duced vessel wall thickening , AFs differentiation , proliferation and collagen deposition in aortic adventitia induced by Ang II infusion , which were mediated by NF-κB and SOCS3/JAK/STAT signaling pathways in blood pressure-dependent and -independent manners , re-spectively.CONCLUSION:We concluded that CYP2J2 overexpression attenuated Ang II-induced adventitial remodeling via PPARγ-dependent NF-κB and PPARγ-independent SOCS 3/JAK/STAT inflammatory signaling pathways .