P-450-dependent Epoxygenase Pathway of Arachidonic Acid Is Involved in Myeloma-induced Angiogenesis of Endothelial Cells

P-450-dependent epoxygenase pathway of arachidonic acid and the products of epoxyeicosatrienoic acids（EETs） have been demonstrated to be involved in angiogenesis and tumor progression.This study examined the expression of EETs and the role of the pathway in the angiogenesis of multiple myeloma（MM）.MM cell lines of U266 and RPMI8226 were cultured,and the EETs levels（11,12-EET and 14,15-EET） in the supernatant were determined by ELISA.Human umbilical vein endothelial cells（HUVECs） were cultured and used for analysis of the angiogenesis activity of the two MM cell lines,which was examined both in vitro and in vivo by employing MTT,chemotaxis,tube formation and matrigel plug assays.11,12-EET and 14,15-EET were found in the supernatant of the cultured MM cells.The levels of the two EETs in the supernatant of U266 cells were significantly higher than those in the RPMI8226 cell supernatant（P〈0.05）,and the levels paralleled the respective angiogenesis activity of the two different MM cell lines.17-octadecynoic acid（17-ODYA）,as a specific inhibitor of P450 enzyme,suppressed HUVECs proliferation and tube formation induced by MM cells.Furthermore,17-ODYA decreased the EET levels in the supernatant of MM cells.These results suggest that EETs may play an important role in the angiogenesis of MM,and the inhibitor 17-ODYA suppresses this effect.

Increased Soluble Epoxide Hydrolase Activity Positively Correlates with Mortality in Heart Failure Patients with Preserved Ejection Fraction:Evidence from Metabolomics

Epoxyeicosatrienoic acids(EETs)have pleiotropic endogenous cardiovascular protective effects and can be hydrolyzed to the corresponding dihydroxyeicosatrienoic acids by soluble epoxide hydrolase(sEH).Heart failure with preserved ejection fraction(HFpEF)has shown an increased prevalence and worse prognosis over the decades.However,the role of sEH activ-ity in HFpEF remains unclear.We enrolled 500 patients with HFpEF and 500 healthy controls between February 2010 and March 2016.Eight types of sEH-related eicosanoids were measured according to target metabolomics,and their correlation with clinical endpoints was also analyzed.The primary endpoint was cardiac mortality,and the secondary endpoint was a composite of cardiac events,including heart failure(HF)readmission,cardiogenic hospitalization,and all-cause mortal-ity.Furthermore,the effect of sEH inhibitors on cardiac diastolic function in HFpEF was investigated in vivo and in vitro.Patients with HFpEF showed significantly enhanced EET degradation by the sEH enzyme compared with healthy controls.More importantly,sEH activity was positively correlated with cardiac mortality in patients with HFpEF,especially in older patients with arrhythmia.A consistent result was obtained in the multiple adjusted models.Decreased sEH activity by the sEH inhibitor showed a significant effective effect on the improvement of cardiac diastolic function by ameliorating lipid disorders in cardiomyocytes of HFpEF mouse model.This study demonstrated that increased sEH activity was associated with cardiac mortality in patients with HFpEF and suggested that sEH inhibition could be a promising therapeutic strategy to improve diastolic cardiac function.Clinical trial identifier:NCT03461107(https://clini caltr ials.gov).

Site-directed deuteration of dronedarone preserves cytochrome P4502J2 activity and mitigates its cardiac adverse effects in canine arrhythmic hearts

Cytochrome P4502J2(CYP2J2)metabolizes arachidonic acid(AA)to cardioprotective epoxyeicosatrienoic acids(EETs).Dronedarone,an antiarrhythmic drug prescribed for treatment of atrial fibrillation(AF)induces cardiac adverse effects(AEs)with poorly understood mechanisms.We previously demonstrated that dronedarone inactivates CYP2J2 potently and irreversibly,disrupts AA-EET pathway leading to cardiac mitochondrial toxicity rescuable via EET enrichment.In this study,we investigated if mitigation of CYP2J2 inhibition prevents dronedarone-induced cardiac AEs.We first synthesized a deuterated analogue of dronedarone(termed poyendarone)and demonstrated that it neither inactivates CYP2J2,disrupts AA-EETs metabolism nor causes cardiac mitochondrial toxicity in vitro.Our patch-clamp experiments demonstrated that pharmacoelectrophysiology of dronedarone is unaffected by deuteration.Next,we show that dronedarone treatment or CYP2J2 knockdown in spontaneously beating cardiomyocytes indicative of depleted CYP2J2 activity exacerbates beat-to-beat(BTB)variability reflective of proarrhythmic phenotype.In contrast,poyendarone treatment yields significantly lower BTB variability compared to dronedarone in cardiomyocytes indicative of preserved CYP2J2 activity.Importantly,poyendarone and dronedarone display similar antiarrhythmic properties in the canine model of persistent AF,while poyendarone substantially reduces beat-to-beat variability of repolarization duration suggestive of diminished proarrhythmic risk.Our findings prove that deuteration of dronedarone prevents CYP2J2 inactivation and mitigates dronedarone-induced cardiac AEs.