The New Mechanism Of Epoxyeicosatrienoic Acids Upregulation On Inhibiting Obesity And Associated Heart Injury

Objective:We have shown before that epoxyeicosatrienoic acids(EETs),specifically 11,12 and 14,15 EETs,reduce adipogenesis in human mesenchymal stem cells and mouse preadipocytes(3T-3L1).In this advancement study,we explore the effects of soluble epoxide hydrolase(sEH)deletion on various aspects of adipocyte-function,including programing for white vs.beige-like fat,and mitochondrial and thermogenic gene-expressions.We further hypothesize that EETs and heme-oxygenase 1(HO-1)form a synergistic,functional module whose effects on adipocyte and vascular function is greater than the effects of sEH deletion alone.Methods:For in vitro studies,the human bone marrow-derived MSCs were used to different into adipocytes,the cells were treated with 11,12-EET and 14,15-EET(1 M)alone and with sEH inhibitor(AUDA)(1 M),or with sEH siRNA,Oil Red O staining was used to determine the size of adipocyte.16 Male sEH null mice were provided by Dr.Darryl C.Zeldin at age of 12 weeks.Mice were fed with high fat diet and had free access to water,all mice were divided in to 3 groups(n=8):1)Control;2)sEH-KO male mice;3)sEH-KO+CoPP male mice.Cobalt protoporphyrin IX(CoPP)(3mg/kg once a week)was administered i.p.for 8 weeks.At sacrifice,adipocyte tissues were immediately collected,weighed.RT-PCR was used to measure gene expression in both cells and tissue,the genes include HO-1,NOV,TNF-?,Mfn1,Mfn2,COX-1,Fis1 and UCP1.EETs were extracted using solid phase C18-ODS AccuBond II 500-mg cartridges,and superoxide in adipocyte tissues were measured in a liquid scintillation counter.Results:For in vitro studies,we examined the effect of sEH inhibitors on hMSC-derived adipocyte.MSC-derived adipocytes exposed to AUDA,an inhibitor of sEH,exhibit an increased number of small and healthy adipocytes,an effect reproduced by siRNA for sEH.In vivo studies show that sEH deletion results in a significant decrease in body weight(29.37±2.46 vs.35.73±3.17,p<0.05),inflammatory adipokue NOV(1.51±0.22 vs.1.14±0.21,p<0.05)?TNF?(1.53±0.21 vs.1.12±0.19,p<0.05).These findings are associated with a decrease in body weight(p<0.05).Importantly,sEH deletion was associated with significant increase in Mfnl(1.54±0.23 vs.0.79±0.17,p<0.05),COX1(20.07±7.31 vs.3.82±0.79,p<0.05),and thermogenic genes UCP1(1.63±0.12 vs.0,81±0.13,p<0.05)and adiponectin(2.48±0.37 vs.1.42±0.21,p<0.05).sEH deletion was manifested by a significant increase in EETs isomers 5,6-8,9-11,12-and 14,15-EETs and an increased EET/DHETES ratio(p<0.05).Notably,activation of HO-1 gene expression further increased the levels of EETs,suggesting that the antioxidant HO-1 system protects EETs from degradation by ROS(86.42±13.38 vs.174.43±54.71,p<0.05).Conclusion:These results provide evidence that sEH deletion while increasing EET levels,resulted in the reprograming of white fat to express mitochondrial and thermogenic genes,a phenotype characteristic of beige-fat.Thus,upregulation of EET and HO-1 may have therapeutic potential in the treatment of metabolic syndrome and obesity.