The Role Of Acot1 In Doxorubicin-induced Cardiotoxicity

Background:Adriamycin(Doxorubicin,DOX)can be used in clinical work for the treatment of a variety of solid tumor and blood tumor diseases,however,its cardiac-toxic side effects greatly limit its further application.DOX can cause and increase reactive oxygen species production and is considered to be one of the most important molecular mechanisms that cause DIC.It has been shown that a novel form of regulated cell death(RCD),ferroptosis,is involved in the process of cell death caused by iron overload,resulting in significant intracellular lipid peroxidation.Yet,the effects of ferroptosis in DIC,which is charactered with significantly iron overload,have not been fully clarified.In the current study,we explore the existence of ferroptosis and its regulatory mechanism in the process of DIC.We then confirm the protective effect of Acot1 in the course of DIC is due to its anti-lipid peroxidation effect and therefore inhibits ferroptosis in cardiomyocytes.Methods & Results:1.DOX(cumulative dose 25 mg/kg)was given to C57BL6/J mice via intraperitoneal injection,and a subacute model of DIC was then established after 14 days of treatment.Survival analysis suggested that DOX significantly increased the mortality rate in mice,and the echocardiography analysis show the DOX-induced damage to cardiac function was mainly characterized by the reduced contractile ability,accompanied by dilated left ventricular.2.Transcriptomics-bioinformatics analysis was carried out through RNA-seq using murine myocardial tissue and genes with significant changes in the process of DIC were screened out.The bio-pathways of differential enrichment were also identified.Transcriptomics-bioinformatics analysis showed a significant reduction in m RNA expression levels of genes,including Acot1,associated with the biosynthesis of unsaturated fatty acids in the cardiomyocytes of DOX treated mice.3.In animal experiments,Fer-1,a ferroptosis-specific small molecular inhibitor,was used to identify the presence of ferroptosis in DIC.The cardiac function of Fer-1treated mice were better than control mice.And a lower mortality rate was also observed in Fer-1 mice.Microstructure observation suggested that DOX treated murine cardiomyocytes with significant edema as well as lipofuscin deposition,while Fer-1reduced these pathology changes.The electron transmission microscopy witnessed DOX-induced significant myolysis,myofilament loss,and disarrangement in cardiomyocytes,all ferroptosis characteristic changes.The increased level of MDA was also observed in the DOX-treated group,as well as Ptgs2 expression level.The above indicators were reduced in Fer-1 treated mice.4.In cell experiments,the model of cardiomyocytes damage caused by RSL-3,a ferroptosis-specific small molecular inducer,and DOX were established using the cell line of mice cardiomyocyte(HL-1).The discovery in the transcriptome was verified.Plasmid and small interference RNA were transfected to HL-1 cells to observe the effects of Acot1 expression on DIC.Both DOX and RSL-3 can induce significant lipid peroxidation,resulting in cardiomyocytes’ death.Acot1 was significantly reduced in the DIC model.After using si RNA to knock-down Acot1 expression,lipid peroxidation in cardiomyocyte and cell death were both increased,while over-expression of Acot1 inhibits them all.5.Changes in the content of free fatty acids in myocardial specific transgenicαMHC-Acot1 mice were detected by GC-MS.In the heart tissue of Acot1 cardiacspecific transgenic mice,a significantly increased concentration of free DHA(C22:6)was observed.DHA treated HL-1 cardiomyocytes show enhanced sensitivity to DOX cytotoxicity,while Acot1 over-expression and Fer-1 treatment can inhibit DHAenhanced DOX cytotoxicity.:Conclusion:The current study highlighted that DIC was mainly related to the reduction of left ventricular contractile function,in which the mechanism of ferroptosis was involved,and lipid peroxidation played an important role.Fer-1 can inhibit the peroxidation of lipids and reduce the death of cardiomyocytes in DOX-treated mice.Preserved cardiac function and reduced mortality rate were also observed in Fer-1 treated mice.In the subacute phase of myocardial toxicity induced by DOX,several genes associated with the biosynthesis of polyunsaturated fatty acids were affected.The Acot1 gene was one of the most significantly altered genes.Changes in the Acot1 gene affect the content of free fatty acids,especially DHA,in cardiomyocytes through the hydrolysis of acylCo As.Furthermore,it may affect the relative composition of unsaturated fatty acids in the membrane structure of the cell,altering the sensitivity of myocardial cells to ferroptosis in DIC.Inhibiting the initiation of ferroptosis in cardiomyocytes may become a new strategy for the treatment of patients with DIC and provide new insights and methods for clinical practice.