The Role And Mechanism Of TRIM8 In Mouse Cardiomyocyte Apoptosis Induced By High Glucose And High Free Fatty Acid

Objectives:To investigate the effects of tripartite motif 8(TRIM8)on the apoptosis of mouse cardiomyocytes(MCMs)induced by high glucose and high free fatty acid and the underlying mechanism.Methods:MCMs were divided into normal glucose group(glucose at 5.5 mmol/L,NG),High glucose group(glucose at 33 mmol/L,HG),High free fatty acid group(free fatty acid at 300 μmol/L,HF)and high glucose combined with high free fatty acid group(glucose at 33 mmol/L,free fatty acid at 300 μmol/L,HGHF).Then,the expression of TRIM8 in the MCMs was knocked-down by siRNA,and the MCMs was further divided into Control group,Scramble siRNA/PBS group,TRIM8 siRNA/PBS group,Scramble siRNA/HGHF group and TRIM8 siRNA/HGHF group.In order to further confirm the specific mechanism of TRIM8 in high glucose-induced MCM injury,the MCMs was subgrouped into HGHF/DMSO group,HGHF+Ts/DMSO group,HGHF/ML385 group and HGHF+Ts/ML385 group.Therefore,apoptosis was analyzed by flow cytometry,the levels of reactive oxygen species(ROS)were measured by DHE staining and flow cytometry.The expression of TRIM8,Nrf2,Gclc,Ho-1,and Nqo-1 at mRNA and protein levels was determined by qPCR and Western blot.Results:The HGHF increased the expression of TRIM8,and suppressed the expression of Nrf2,Gclc,Ho-1 and Nqo-1 in the MCMs(P<0.05).Compared with Scramble siRNA/HGHF group,the intracellular ROS content and apoptotic rate were decreased in TRIM8-siRNA/HGHF group(P<0.05).Correspondingly,the expression of the antioxidant molecule Nrf2 and its downstream genes Gclc,Ho-1 and Nqo-1 was increased.In contrast,the addition of Nrf2 inhibitor ML385 partially reversed the inhibitory effect of TRIM8 expression knock-down on high glucose and high fat-induced apoptosis of MCMs.Conclusion:TRIM8 exacerbates the HGHF induced cardiomyocyte apoptosis by modulating Nrf2 antioxidative pathway.