Luca Liberale1,2, Alexander Akhmedov1, Nikolaos I Vlachogiannis3, Nicole R Bonetti1,4, Vanasa Nageswaran5, Melroy X Miranda1, Yustina M Puspitasari1, Lena Schwarz1, Sarah Costantino1, Francesco Paneni1,6,7, Jürg H Beer1,4, Frank Ruschitzka6, Fabrizio Montecucco8,9, Thomas F Lüscher1,10, Kimon Stamatelopoulos3,11, Konstantinos Stellos3,12, Giovanni G Camici1,6,7,13. 1. Center for Molecular Cardiology, Schlieren Campus, University of Zurich, Wagistrasse 12, 8952 Schlieren, Switzerland. 2. First Clinic of Internal Medicine, Department of Internal Medicine, University of Genoa, 6 viale Benedetto XV, 16132 Genoa, Italy. 3. Biosciences Institute, Vascular Biology and Medicine Theme, Faculty of Medical Sciences, Newcastle University, Framlington Place, NE2 4HH Newcastle upon Tyne, UK. 4. Department of Internal Medicine, Cantonal Hospital of Baden, Im Ergel 1, 5404 Baden, Switzerland. 5. Department of Cardiology, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Hindenburgdamm 30, 12203 Berlin, Germany. 6. Department of Cardiology, University Heart Center, University Hospital Zurich, Rämistrasse 100, 8092 Zurich, Switzerland. 7. Department of Research and Education, University Hospital Zurich, Rämistrasse 100, 8092 Zurich, Switzerland. 8. IRCCS Ospedale Policlinico San Martino Genoa-Italian Cardiovascular Network, L.go R. Benzi 10, 16132 Genoa, Italy. 9. First Clinic of Internal Medicine, Department of Internal Medicine and Centre of Excellence for Biomedical Research (CEBR), University of Genoa, 6 viale Benedetto XV, 16132 Genoa, Italy. 10. Royal Brompton and Harefield Hospitals and Imperial College, Dovehouse Street, London SW3 6LY, UK. 11. Department of Clinical Therapeutics, Alexandra Hospital, University of Athens, Lourou 4-2, 115 28 Athens, Greece. 12. Department of Cardiology, Newcastle Hospitals NHS Foundation Trust, Freeman Rd, High Heaton, Newcastle upon Tyne NE7 7DN, UK. 13. Zurich Neuroscience Center, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
Abstract
AIMS: Arterial thrombosis as a result of plaque rupture or erosion is a key event in acute cardiovascular events. Sirtuin 5 (SIRT5) belongs to the lifespan-regulating sirtuin superfamily and has been implicated in acute ischaemic stroke and cardiac hypertrophy. This project aims at investigating the role of SIRT5 in arterial thrombus formation. METHODS AND RESULTS: Sirt5 transgenic (Sirt5Tg/0) and knock-out (Sirt5-/-) mice underwent photochemically induced carotid endothelial injury to trigger arterial thrombosis. Primary human aortic endothelial cells (HAECs) were treated with SIRT5 silencing-RNA (si-SIRT5) as well as peripheral blood mononuclear cells from acute coronary syndrome (ACS) patients and non-ACS controls (case-control study, total n = 171) were used to increase the translational relevance of our data. Compared to wild-type controls, Sirt5Tg/0 mice displayed accelerated arterial thrombus formation following endothelial-specific damage. Conversely, in Sirt5-/- mice, arterial thrombosis was blunted. Platelet function was unaltered, as assessed by ex vivo collagen-induced aggregometry. Similarly, activation of the coagulation cascade as assessed by vascular and plasma tissue factor (TF) and TF pathway inhibitor expression was unaltered. Increased thrombus embolization episodes and circulating D-dimer levels suggested augmented activation of the fibrinolytic system in Sirt5-/- mice. Accordingly, Sirt5-/- mice showed reduced plasma and vascular expression of the fibrinolysis inhibitor plasminogen activator inhibitor (PAI)-1. In HAECs, SIRT5-silencing inhibited PAI-1 gene and protein expression in response to TNF-α. This effect was mediated by increased AMPK activation and reduced phosphorylation of the MAP kinase ERK 1/2, but not JNK and p38 as shown both in vivo and in vitro. Lastly, both PAI-1 and SIRT5 gene expressions are increased in ACS patients compared to non-ACS controls after adjustment for cardiovascular risk factors, while PAI-1 expression increased across tertiles of SIRT5. CONCLUSION: SIRT5 promotes arterial thrombosis by modulating fibrinolysis through endothelial PAI-1 expression. Hence, SIRT5 may be an interesting therapeutic target in the context of atherothrombotic events. Published on behalf of the European Society of Cardiology. All rights reserved.
AIMS: Arterial thrombosis as a result of plaque rupture or erosion is a key event in acute cardiovascular events. Sirtuin 5 (SIRT5) belongs to the lifespan-regulating sirtuin superfamily and has been implicated in acute ischaemic stroke and cardiac hypertrophy. This project aims at investigating the role of SIRT5 in arterial thrombus formation. METHODS AND RESULTS: Sirt5 transgenic (Sirt5Tg/0) and knock-out (Sirt5-/-) mice underwent photochemically induced carotid endothelial injury to trigger arterial thrombosis. Primary human aortic endothelial cells (HAECs) were treated with SIRT5 silencing-RNA (si-SIRT5) as well as peripheral blood mononuclear cells from acute coronary syndrome (ACS) patients and non-ACS controls (case-control study, total n = 171) were used to increase the translational relevance of our data. Compared to wild-type controls, Sirt5Tg/0 mice displayed accelerated arterial thrombus formation following endothelial-specific damage. Conversely, in Sirt5-/- mice, arterial thrombosis was blunted. Platelet function was unaltered, as assessed by ex vivo collagen-induced aggregometry. Similarly, activation of the coagulation cascade as assessed by vascular and plasma tissue factor (TF) and TF pathway inhibitor expression was unaltered. Increased thrombus embolization episodes and circulating D-dimer levels suggested augmented activation of the fibrinolytic system in Sirt5-/- mice. Accordingly, Sirt5-/- mice showed reduced plasma and vascular expression of the fibrinolysis inhibitor plasminogen activator inhibitor (PAI)-1. In HAECs, SIRT5-silencing inhibited PAI-1 gene and protein expression in response to TNF-α. This effect was mediated by increased AMPK activation and reduced phosphorylation of the MAP kinase ERK 1/2, but not JNK and p38 as shown both in vivo and in vitro. Lastly, both PAI-1 and SIRT5 gene expressions are increased in ACS patients compared to non-ACS controls after adjustment for cardiovascular risk factors, while PAI-1 expression increased across tertiles of SIRT5. CONCLUSION: SIRT5 promotes arterial thrombosis by modulating fibrinolysis through endothelial PAI-1 expression. Hence, SIRT5 may be an interesting therapeutic target in the context of atherothrombotic events. Published on behalf of the European Society of Cardiology. All rights reserved.