Luca Liberale1,2, Daniel S Gaul1, Alexander Akhmedov1, Nicole R Bonetti1,3, Vanasa Nageswaran4, Sarah Costantino1, Jürgen Pahla1, Julien Weber5, Vera Fehr1, Daria Vdovenko1, Aurora Semerano6, Giacomo Giacalone6, Gerd A Kullak-Ublick7, Maria Sessa6, Urs Eriksson1,8, Francesco Paneni1,9,10, Frank Ruschitzka9, Fabrizio Montecucco11,12, Jürg H Beer1,3, Thomas F Lüscher1,13, Christian M Matter1,9, Giovanni G Camici1,9,10,14. 1. Center for Molecular Cardiology, Schlieren Campus, University of Zurich, Wagistrasse 12, Schlieren 8952, Switzerland. 2. First Clinic of Internal Medicine, Department of Internal Medicine, University of Genoa, 6 viale Benedetto XV, Genoa 16132, Italy. 3. Department of Internal Medicine, Cantonal Hospital of Baden, Im Ergel 1, Baden 5404, Switzerland. 4. Department of Cardiology, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Hindenburgdamm 30, Berlin 12203, Germany. 5. Institute of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland. 6. Department of Neurology, San Raffaele Scientific Institute, via Olgettina 60, Milano 20132, Italy. 7. Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, Zurich, Switzerland. 8. GZO Spital Wetzikon, Spitalstrasse 66, Wetzikon 8620, Switzerland. 9. Department of Cardiology, University Heart Center, University Hospital Zurich, Rämistrasse 100, Zurich 8092, Switzerland. 10. Department of Research and Education, University Hospital Zurich, Rämistrasse 100, Zurich 8092, Switzerland. 11. IRCCS Ospedale Policlinico San Martino Genoa - Italian Cardiovascular Network, L.go R. Benzi 10, Genoa 16132, Italy. 12. First Clinic of Internal Medicine, Department of Internal Medicine, Centre of Excellence for Biomedical Research (CEBR), University of Genoa, 6 viale Benedetto XV, Genoa 16132, Italy. 13. Royal Brompton and Harefield Hospitals, Imperial College, Dovehouse Street, London SW3 6LY, UK. 14. Zurich Neuroscience Center, University of Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland.
Abstract
AIMS: Aging is an established risk factor for stroke; genes regulating longevity are implicated in the pathogenesis of ischaemic stroke where to date, therapeutic options remain limited. The blood-brain barrier (BBB) is crucially involved in ischaemia/reperfusion (I/R) brain injury thus representing an attractive target for developing novel therapeutic agents. Given the role of endothelial cells in the BBB, we hypothesized that the endothelial-specific expression of the recently described longevity gene SIRT6 may exhibit protective properties in stroke. METHODS AND RESULTS: SIRT6 endothelial expression was reduced following stroke. Endothelial-specific Sirt6 knockout (eSirt6-/-) mice, as well as animals in which Sirt6 overexpression was post-ischaemically induced, underwent transient middle cerebral artery occlusion (tMCAO). eSirt6-/- animals displayed increased infarct volumes, mortality, and neurological deficit after tMCAO, as compared to control littermates. Conversely, post-ischaemic Sirt6 overexpression decreased infarct size and neurological deficit. Analysis of ischaemic brain sections revealed increased BBB damage and endothelial expression of cleaved caspase-3 in eSIRT6-/- mice as compared to controls. In primary human brain microvascular endothelial cells (HBMVECs), hypoxia/reoxygenation (H/R) reduced SIRT6 expression and SIRT6 silencing impaired the barrier function (transendothelial resistance) similar to what was observed in mice exposed to I/R. Further, SIRT6-silenced HBMVECs exposed to H/R showed reduced viability, increased cleaved caspase-3 expression and reduced activation of the survival pathway Akt. In ischaemic stroke patients, SIRT6 expression was higher in those with short-term neurological improvement as assessed by NIHSS scale and correlated with stroke outcome. CONCLUSION: Endothelial SIRT6 exerts a protective role in ischaemic stroke by blunting I/R-mediated BBB damage and thus, it may represent an interesting novel therapeutic target to be explored in future clinical investigation. Published on behalf of the European Society of Cardiology. All rights reserved.
AIMS: Aging is an established risk factor for stroke; genes regulating longevity are implicated in the pathogenesis of ischaemic stroke where to date, therapeutic options remain limited. The blood-brain barrier (BBB) is crucially involved in ischaemia/reperfusion (I/R) brain injury thus representing an attractive target for developing novel therapeutic agents. Given the role of endothelial cells in the BBB, we hypothesized that the endothelial-specific expression of the recently described longevity gene SIRT6 may exhibit protective properties in stroke. METHODS AND RESULTS: SIRT6 endothelial expression was reduced following stroke. Endothelial-specific Sirt6 knockout (eSirt6-/-) mice, as well as animals in which Sirt6 overexpression was post-ischaemically induced, underwent transient middle cerebral artery occlusion (tMCAO). eSirt6-/- animals displayed increased infarct volumes, mortality, and neurological deficit after tMCAO, as compared to control littermates. Conversely, post-ischaemic Sirt6 overexpression decreased infarct size and neurological deficit. Analysis of ischaemic brain sections revealed increased BBB damage and endothelial expression of cleaved caspase-3 in eSIRT6-/- mice as compared to controls. In primary human brain microvascular endothelial cells (HBMVECs), hypoxia/reoxygenation (H/R) reduced SIRT6 expression and SIRT6 silencing impaired the barrier function (transendothelial resistance) similar to what was observed in mice exposed to I/R. Further, SIRT6-silenced HBMVECs exposed to H/R showed reduced viability, increased cleaved caspase-3 expression and reduced activation of the survival pathway Akt. In ischaemic stroke patients, SIRT6 expression was higher in those with short-term neurological improvement as assessed by NIHSS scale and correlated with stroke outcome. CONCLUSION: Endothelial SIRT6 exerts a protective role in ischaemic stroke by blunting I/R-mediated BBB damage and thus, it may represent an interesting novel therapeutic target to be explored in future clinical investigation. Published on behalf of the European Society of Cardiology. All rights reserved.
Authors: Luca Liberale; Nicole R Bonetti; Yustina M Puspitasari; Ana Vukolic; Alexander Akhmedov; Candela Diaz-Cañestro; Stephan Keller; Fabrizio Montecucco; Mario Merlini; Aurora Semerano; Giacomo Giacalone; Marco Bacigaluppi; Maria Sessa; Frank Ruschitzka; Thomas F Lüscher; Peter Libby; Jürg H Beer; Giovanni G Camici Journal: Eur J Clin Invest Date: 2021-06-02 Impact factor: 4.686