EXCHANGE PROTEIN DIRECTLY ACTIVATED BY CAMP 1, PROMOTES IRON-MEDIATED CARDIOMYOCYTE DEATH

Iron-overloading conditions promotes cardiac dysfunction and failure. Ferroptosis is a new form of regulated cell death that is characterized by iron overload, leading to the accumulation of lethal levels of ROS and lipid peroxidation. Our previous RNA-Sequencing analysis performed in neonatal rat ventricular myocytes (NRVMs) showed that pharmacological modulation of Exchange protein directly activated by cAMP 1 (EPAC1) regulated gene markers of ferroptosis such as transferrin receptor (tfrc), soluble carrier 40A1 (slc40a1), Acyl-CoA synthetase long chain family member 4 (acsl4).



This study aims to determine the role of EPAC1 in cardiomyocyte iron metabolism and its implication in iron-mediated cell death of cardiomyocytes.



As expected, a known ferroptosis inducer, erastin induced concentration-dependent cardiomyocyte death, as assessed by LDH release. Consistently, micromolar concentrations of erastin promoted ROS and lipid peroxidation accumulation in NRVMs. To further confirm a potential impact of EPAC1 protein in erastin-induced ferroptosis cell death, we used a pharmacological EPAC1 inhibitor, AM-001. Analysis of cell viability revealed that AM-001 markedly prevented erastin-induced cell death in NRVMs. Accordingly, we found that the increase in ROS levels and accumulation of lipid peroxides after erastin treatment were prevented in NRVMS pretreated with AM-001 (20 µM). Similarly, iron accumulation, ROS as well as cell death were prevented in NRVMs treated with ferric ammonium citrate (100 µM) and AM-001 (20 µM).



Altogether our data show that EPAC1 blockade prevents iron-induced cell death in NRVMs. These results will further be confirmed in in vivo mouse models of cardiomyopathy induced by doxorubicin or iron dextran.