Loubina Fazal1, Marion Laudette1, Sílvia Paula-Gomes1, Sandrine Pons1, Caroline Conte1, Florence Tortosa1, Pierre Sicard1, Yannis Sainte-Marie1, Malik Bisserier1, Olivier Lairez1, Alexandre Lucas1, Jérôme Roy1, Bijan Ghaleh1, Jérémy Fauconnier1, Jeanne Mialet-Perez1, Frank Lezoualc'h2. 1. From the Inserm, UMR-1048, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France (L.F., M.L., S.P.-G., C.C., F.T., P.S., Y.S.-M., M.B., O.L., A.L., J.M.-P., F.L.); Université de Toulouse, France (L.F., M.L., S.P.-G., C.C., F.T., P.S., Y.S.-M., M.B., O.L., A.L., J.M.-P., F.L.); Inserm, U955, Equipe 03, F-94000, Créteil, France (S.P., B.G.), and Inserm, UMR-1046 (J.R., J.F.); and UMR CNRS-9214, PHYMEDEX, Université de Montpellier, France (J.R., J.F.). 2. From the Inserm, UMR-1048, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France (L.F., M.L., S.P.-G., C.C., F.T., P.S., Y.S.-M., M.B., O.L., A.L., J.M.-P., F.L.); Université de Toulouse, France (L.F., M.L., S.P.-G., C.C., F.T., P.S., Y.S.-M., M.B., O.L., A.L., J.M.-P., F.L.); Inserm, U955, Equipe 03, F-94000, Créteil, France (S.P., B.G.), and Inserm, UMR-1046 (J.R., J.F.); and UMR CNRS-9214, PHYMEDEX, Université de Montpellier, France (J.R., J.F.). Frank.Lezoualch@inserm.fr.
Abstract
RATIONALE: Although the second messenger cyclic AMP (cAMP) is physiologically beneficial in the heart, it largely contributes to cardiac disease progression when dysregulated. Current evidence suggests that cAMP is produced within mitochondria. However, mitochondrial cAMP signaling and its involvement in cardiac pathophysiology are far from being understood. OBJECTIVE: To investigate the role of MitEpac1 (mitochondrial exchange protein directly activated by cAMP 1) in ischemia/reperfusion injury. METHODS AND RESULTS: We show that Epac1 (exchange protein directly activated by cAMP 1) genetic ablation (Epac1-/-) protects against experimental myocardial ischemia/reperfusion injury with reduced infarct size and cardiomyocyte apoptosis. As observed in vivo, Epac1 inhibition prevents hypoxia/reoxygenation-induced adult cardiomyocyte apoptosis. Interestingly, a deleted form of Epac1 in its mitochondrial-targeting sequence protects against hypoxia/reoxygenation-induced cell death. Mechanistically, Epac1 favors Ca2+ exchange between the endoplasmic reticulum and the mitochondrion, by increasing interaction with a macromolecular complex composed of the VDAC1 (voltage-dependent anion channel 1), the GRP75 (chaperone glucose-regulated protein 75), and the IP3R1 (inositol-1,4,5-triphosphate receptor 1), leading to mitochondrial Ca2+ overload and opening of the mitochondrial permeability transition pore. In addition, our findings demonstrate that MitEpac1 inhibits isocitrate dehydrogenase 2 via the mitochondrial recruitment of CaMKII (Ca2+/calmodulin-dependent protein kinase II), which decreases nicotinamide adenine dinucleotide phosphate hydrogen synthesis, thereby, reducing the antioxidant capabilities of the cardiomyocyte. CONCLUSIONS: Our results reveal the existence, within mitochondria, of different cAMP-Epac1 microdomains that control myocardial cell death. In addition, our findings suggest Epac1 as a promising target for the treatment of ischemia-induced myocardial damage.
RATIONALE: Although the second messenger cyclic AMP (cAMP) is physiologically beneficial in the heart, it largely contributes to cardiac disease progression when dysregulated. Current evidence suggests that cAMP is produced within mitochondria. However, mitochondrial cAMP signaling and its involvement in cardiac pathophysiology are far from being understood. OBJECTIVE: To investigate the role of MitEpac1 (mitochondrial exchange protein directly activated by cAMP 1) in ischemia/reperfusion injury. METHODS AND RESULTS: We show that Epac1 (exchange protein directly activated by cAMP 1) genetic ablation (Epac1-/-) protects against experimental myocardial ischemia/reperfusion injury with reduced infarct size and cardiomyocyte apoptosis. As observed in vivo, Epac1 inhibition prevents hypoxia/reoxygenation-induced adult cardiomyocyte apoptosis. Interestingly, a deleted form of Epac1 in its mitochondrial-targeting sequence protects against hypoxia/reoxygenation-induced cell death. Mechanistically, Epac1 favors Ca2+ exchange between the endoplasmic reticulum and the mitochondrion, by increasing interaction with a macromolecular complex composed of the VDAC1 (voltage-dependent anion channel 1), the GRP75 (chaperone glucose-regulated protein 75), and the IP3R1 (inositol-1,4,5-triphosphate receptor 1), leading to mitochondrial Ca2+ overload and opening of the mitochondrial permeability transition pore. In addition, our findings demonstrate that MitEpac1 inhibits isocitrate dehydrogenase 2 via the mitochondrial recruitment of CaMKII (Ca2+/calmodulin-dependent protein kinase II), which decreases nicotinamide adenine dinucleotide phosphatehydrogen synthesis, thereby, reducing the antioxidant capabilities of the cardiomyocyte. CONCLUSIONS: Our results reveal the existence, within mitochondria, of different cAMP-Epac1 microdomains that control myocardial cell death. In addition, our findings suggest Epac1 as a promising target for the treatment of ischemia-induced myocardial damage.
Authors: Klaus Aktories; Peter Gierschik; Dagmar Meyer Zu Heringdorf; Martina Schmidt; Günter Schultz; Thomas Wieland Journal: Naunyn Schmiedebergs Arch Pharmacol Date: 2019-05-17 Impact factor: 3.000
Authors: Massimo Bonora; Mariusz R Wieckowski; David A Sinclair; Guido Kroemer; Paolo Pinton; Lorenzo Galluzzi Journal: Nat Rev Cardiol Date: 2019-01 Impact factor: 32.419