Candela Diaz-Cañestro1, Mario Merlini2, Nicole R Bonetti1, Luca Liberale3, Patricia Wüst1, Sylvie Briand-Schumacher1, Jan Klohs4, Sara Costantino1, Melroy Miranda1, Gabriele Schoedon-Geiser5, Gerd A Kullak-Ublick6, Alexander Akhmedov1, Francesco Paneni7, Jürg H Beer8, Thomas F Lüscher7, Giovanni G Camici9. 1. Center for Molecular Cardiology, University of Zurich, Schlieren, Switzerland. 2. Gladstone Institute of Neurological Disease, University of California, San Francisco, San Francisco, CA, USA. 3. Center for Molecular Cardiology, University of Zurich, Schlieren, Switzerland,; First Clinic of Internal Medicine, Department of Internal Medicine, University of Genoa, Genoa, Italy. 4. Institute for Biomedical Engineering, Swiss Federal Institute of Technology Zurich (ETHZ), Zurich, Switzerland. 5. Inflammation Research Unit, Division of Internal Medicine, University Hospital Zurich, Zurich, Switzerland. 6. Division of Clinical Pharmacology and Toxicology, University Hospital Zurich, Zurich, Switzerland. 7. Center for Molecular Cardiology, University of Zurich, Schlieren, Switzerland,; Department of Cardiology, University Heart Center, University Hospital Zurich, Zurich, Switzerland. 8. Center for Molecular Cardiology, University of Zurich, Schlieren, Switzerland,; Department of Internal Medicine, Cantonal Hospital Baden, Baden, Switzerland. 9. Center for Molecular Cardiology, University of Zurich, Schlieren, Switzerland,; Department of Cardiology, University Heart Center, University Hospital Zurich, Zurich, Switzerland; Zurich Neuroscience Center (ZNZ), Zurich, Switzerland. Electronic address: giovanni.camici@uzh.ch.
Abstract
BACKGROUND: In acute ischemic stroke (AIS) patients, impaired blood-brain barrier (BBB) integrity is associated with hemorrhagic transformation and worsened outcome. Yet, the mechanisms underlying these relationships are poorly understood and consequently therapeutic strategies are lacking. This study sought to determine whether SIRT5 contributes to BBB damage following I/R brain injury. METHODS AND RESULTS: SIRT5 knockout (SIRT5-/-) and wild type (WT) mice underwent transient middle cerebral artery (MCA) occlusion (tMCAO) followed by 48h of reperfusion. Genetic deletion of SIRT5 decreased infarct size, improved neurological function and blunted systemic inflammation following stroke. Similar effects were also achieved by in vivo SIRT5 silencing. Immunohistochemical analysis revealed decreased BBB leakage and degradation of the tight junction protein occludin in SIRT5-/- mice exposed to tMCAO as compared to WT. In primary human brain microvascular endothelial cells (HBMVECs) exposed to hypoxia/reoxygenation (H/R), SIRT5 silencing decreased endothelial permeability and upregulated occludin and claudin-5; this effect was prevented by the PI3K inhibitor wortmannin. Lastly, SIRT5 gene expression was increased in peripheral blood monocytes (PBMCs) of AIS patients at 6h after onset of stroke compared to sex- and age-matched healthy controls. CONCLUSION: SIRT5 is upregulated in PBMCs of AIS patients and in the MCA of WT mice exposed to tMCAO; SIRT5 mediates I/R-induced brain damage by increasing BBB permeability through degradation of occludin. This effect was reproduced in HBMVECs exposed to H/R, mediated by the PI3K/Akt pathway. Our findings shed new light on the mechanisms of I/R-dependent brain damage and suggest SIRT5 as a novel therapeutic target.
BACKGROUND: In acute ischemic stroke (AIS) patients, impaired blood-brain barrier (BBB) integrity is associated with hemorrhagic transformation and worsened outcome. Yet, the mechanisms underlying these relationships are poorly understood and consequently therapeutic strategies are lacking. This study sought to determine whether SIRT5 contributes to BBB damage following I/R brain injury. METHODS AND RESULTS:SIRT5 knockout (SIRT5-/-) and wild type (WT) mice underwent transient middle cerebral artery (MCA) occlusion (tMCAO) followed by 48h of reperfusion. Genetic deletion of SIRT5 decreased infarct size, improved neurological function and blunted systemic inflammation following stroke. Similar effects were also achieved by in vivo SIRT5 silencing. Immunohistochemical analysis revealed decreased BBB leakage and degradation of the tight junction protein occludin in SIRT5-/- mice exposed to tMCAO as compared to WT. In primary human brain microvascular endothelial cells (HBMVECs) exposed to hypoxia/reoxygenation (H/R), SIRT5 silencing decreased endothelial permeability and upregulated occludin and claudin-5; this effect was prevented by the PI3K inhibitor wortmannin. Lastly, SIRT5 gene expression was increased in peripheral blood monocytes (PBMCs) of AISpatients at 6h after onset of stroke compared to sex- and age-matched healthy controls. CONCLUSION:SIRT5 is upregulated in PBMCs of AISpatients and in the MCA of WT mice exposed to tMCAO; SIRT5 mediates I/R-induced brain damage by increasing BBB permeability through degradation of occludin. This effect was reproduced in HBMVECs exposed to H/R, mediated by the PI3K/Akt pathway. Our findings shed new light on the mechanisms of I/R-dependent brain damage and suggest SIRT5 as a novel therapeutic target.
Authors: Takuto Chiba; Kevin D Peasley; Kasey R Cargill; Katherine V Maringer; Sivakama S Bharathi; Elina Mukherjee; Yuxun Zhang; Anja Holtz; Nathan Basisty; Shiva D Yagobian; Birgit Schilling; Eric S Goetzman; Sunder Sims-Lucas Journal: J Am Soc Nephrol Date: 2019-10-01 Impact factor: 10.121
Authors: Alexander Akhmedov; Nicole R Bonetti; Martin F Reiner; Remo D Spescha; Heidi Amstalden; Mario Merlini; Daniel S Gaul; Candela Diaz-Cañestro; Sylvie Briand-Schumacher; Rebecca S Spescha; Aurora Semerano; Giacomo Giacalone; Gianluigi Savarese; Fabrizio Montecucco; Luka Kulic; Roger M Nitsch; Christian M Matter; Gerd A Kullak-Ublick; Maria Sessa; Thomas F Lüscher; Jürg H Beer; Luca Liberale; Giovanni G Camici Journal: J Cereb Blood Flow Metab Date: 2018-08-03 Impact factor: 6.200
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Authors: Maria Shvedova; Yana Anfinogenova; Elena N Atochina-Vasserman; Igor A Schepetkin; Dmitriy N Atochin Journal: Front Pharmacol Date: 2018-07-05 Impact factor: 5.810