Frataxin Mediates Mitochondrial Damage Induced By Ethanol And The Potential Protection Of Quercetin

Objective:Mitochondrial damage as an early pathological manifestation plays an important role in the pathogenesis of alcoholic liver disease.To investigate the role of frataxin in liver mitochondrial alcoholic injury and the potential effects of the protection of quercetin.Methods:1.In vivo experiment 60 male C57BL/6J mice were randomly divided into 4 groups and pair-fed with either regular or ethanol-containing Lieber De Carli liquids diets for 15 weeks.At the same time,quercetin?100 mg/kg.bw.?was given by gavage according to the body weight.Collecting the Liver tissue samples immediately after the model is completed.The following indexes were detected:?1?The change of mitochondrial ultrastructure and mitochondrial membrane potential;?2?Mitochondrial total iron and labile iron pool?LIP?levels;?3?The content of cytoplasm and mitochondrial ROS;?4?The protein expression of frataxin.2.In vitro experiment shRNA^FXN/shRNA^Controlcells were cultured in DMEM medium containing ethanol?100mM?and/or quercetin?50?M?for 24 h.The following indexes were detected:?1?Mitochondrial membrane potential and cytoplasm ROS level;?2?LIP and FTL protein levels;?3?The protein expression of frataxin,MFRN2,FECH.Results:1.Compared with the normal control group,chronic ethanol intake damaged mitochondrial ultrastructure,decreased mitochondrial membrane potential,significantly increased mitochondrial total iron and LIP levels,increased levels of cytoplasm and mitochondrial ROS,the expression of frataxin protein was reduced.Quercetin intervention improved all the pathological changes induced by ethanol intake.2.Compared with the respective control group,ethanol treatment reduced the level of frataxin protein by 37%in shRNA^Controlontrol cells and 17%in shRNA^FXNXN cells.Frataxin silencing compared to shRNA^Controlontrol cells frataxin protein expression decreased by 65%,shRNA^FXNethanol treatment versus shRNA^Controlethanol treatment,frataxin protein expression was further reduced by 50%.Quercetin significantly rescued the inhibition of frataxin protein expression induced by frataxin silence and ethanol.3.Compared with the respective control group,after ethanol treatment shRNA^Controlontrol and shRNA^FXNXN cells cytoplasmic ROS level was increased,mitochondrial membrane potential and the level of LIP were decreased,the expression of FTL,MFRN2,FECH protein were increased.Compared with shRNA^Controlontrol control group,Frataxin silence also resulted in an increase in cytoplasmic ROS,a decrease in mitochondrial membrane potential and LIP level,whereas the expression of FTL protein was decreased,the expression of FECH,MFRN2 protein were increased.Compared with shRNA^Controlontrol ethanol group,Frataxin silence plus ethanol further changed cytoplasmic ROS level and mitochondrial membrane potential,further decreased LIP level and increased FECH protein level,FTL protein level was less decreased and MFRN2 protein level was increased the same amplitude.Quercetin intervention significantly decreased the level of ROS and increased mitochondrial membrane potential,while obviously reducing LIP level,FTL protein expression,and no significant effect on FECH and MFRN2 protein level.Conclusions:Ethanol intake leads to fratarxin protein expression decreased,mitochondria iron overload and oxidative stress,damaging mitochondrial structure and function.Quercetin protects against alcoholic liver mitochondrial damage by recovering the expression of frataxin protein and preventing mitochondrial iron overload.