Effects Of Elabela On Doxorubicin-induced Cardiotoxicity

Background:Cardio-Oncology is a rising interdisciplinary subject,which mainly focuses on anti-tumor therapy associated cardiotoxicity.Doxorubicin(DOX)remains one of the most prescribed anti-tumor agents around the world.DOXinduced cardiotoxicity(DIC)threatens the health of cancer patients and cancer survivors.Unfortunately,there is still lack of a safe and effective strategy to treat DIC.Elabela(ELA),a newly found endogenous peptide,is indispensable for cardiac development.Recently,studies revealed that ELA exerts cardioprotective effect in multiple cardiovascular diseases,including heart failure,myocardial infarction and hypertension.However,whether ELA is capable of alleviating DIC remains unknown.Objectives:To investigate if ELA ameliorates DIC.Further,the role of autophagic flux in the protection of ELA on DIC is also explored.Methods:6-8 weeks male C57BL mice were used to establish acute DIC models.Echocardiography,serum cTnT and CK-MB,heart weight(HW)/body weight(BW)ratio and WGA staining were measured to evaluate the cardiac function,injury and atrophy of mice,respectively.Neonatal rat cardiomyocytes(NRCs)were isolated and used in vitro studies,phalloidin staining,AM/PI staining and TUNEL staining were applied to analyze cell atrophy and death,respectively.Autophagic flux were monitored by the change of p62 and LC3II in WB as well as autophagic vacuoles in TEM assay in vivo.Additionally,autophagic flux were detected by WB,mRFP-GFP-LC3 puncta and LysoSensor in vitro.Autophagic flux were damaged by chloroquine(CQ)to investigate its role in the protection of ELA on DIC in vivo.Further,whether TFEB signaling pathway participates in the improvement of ELA on DOX-induced autophagic flux impairment as well as cardiomyocyte atrophy and death was explored in vitro.Results:1.DIC was ameliorated by ELA:ELA administration was found to attenuate DOX-induced cardiac dysfunction,cardiac injury and cardiac atrophy in vivo and cell death and atrophy in vitro.2.ELA improved the autophagic flux damaged by DOX:Lysosome acidification dysfunction,autolysosome accumulation and autophagic flux blockage caused by DOX were partially abolished by ELA treatment.3.ELA protected DIC possibly via enhancing autophagic flux:(1)In vivo studies found that the improvement of ELA on DOXinduced cardiac dysfunction and cardiac atrophy was abrogated by chloroquine,an autophagic flux inhibitor.(2)TFEB is a transcription factor mastering the regulation of lysosome function.In vitro studies revealed that ELA reversed the inhibition of TFEB induced by DOX,downregulation of TFEB with TFEB siRNA abated the amelioration of ELA on DOX-induced autophagic flux damage,cell death and atrophy.Conclusion:This study first reported that ELA ameliorates DIC though the restoration of autophagic flux via activating TFEB.ELA might be a promising target in DIC prevention and therapy.