Nikola Sladojevic1, Goo Taeg Oh2,3, Hyung-Hwan Kim2, Lea M Beaulieu4, Hervé Falet5, Karol Kaminski2,6, Jane E Freedman4, James K Liao1,2. 1. Department of Medicine, Section of Cardiology, University of Chicago, 5841 S. Maryland Avenue, Chicago, IL 60637, USA. 2. Department of Medicine, Vascular Medicine Research Unit, Brigham and Women's Hospital and Harvard Medical School, 65 Landsdowne Street, Cambridge, MA 02139, USA. 3. Department of Life Science, Ewha Womans University, 52 Ewhayeodae-gil, Daehyeon-dong, Seodaemun-gu, Seoul, Korea. 4. Department of Medicine, University of Massachusetts Medical School, 55 N. Lake Avenue, Worcester, MA 01655, USA. 5. Division of Hematology, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA. 6. Department of Population Medicine, Medical University of Bialystok, Jana Kilinskiego 1, 15-089, Bialystok, Poland.
Abstract
AIMS: Rho-associated coiled-coil containing kinase (ROCK)-2 is an important mediator of the actin cytoskeleton. Because changes in the actin cytoskeleton are critical for platelet function, we hypothesized that ROCK2 in platelets will play important role in thrombosis and can be potentially a target for therapeutic intervention in thromboembolic stroke. METHODS AND RESULTS: We generated platelet-specific ROCK2-deficient mice (ROCK2Plt-/-) from conditional ROCK2fl°x/fl°x and platelet factor (PF)-4-Cre transgenic mice. Platelets from ROCK2Plt-/- mice were less responsive to thrombin stimulation in terms of pseudopodia formation, collagen adhesion, and in the formation of homotypic and heterotypic aggregates. This corresponded to prolonged bleeding time and delayed vascular occlusion following vessel injury. To determine whether these changes in platelet function could affect thrombotic disease, we utilized a clot-embolic model of ischaemic stroke. When pre-formed clots from ROCK2Plt-/- mice were injected into the middle cerebral artery of control mice, cerebral blood flow recovery occurred more rapidly, leading to decreased cerebral injury and neurological deficits, compared to pre-formed clots from control mice. Interestingly, pre-formed clots from control mice produced similar degree of cerebral injury when injected into control or ROCK2Plt-/- mice, suggesting that platelet ROCK2 deficiency affects clot formation but not propagation. Indeed, in a non-thrombotic intra-filament MCA occlusion model of stroke, platelet ROCK2 deletion was not protective. Furthermore, ROCK2Plt-/- mice exhibit similar atherosclerosis severity and vascular remodeling as control mice. CONCLUSION: These findings indicate that platelet ROCK2 plays important role in platelet function and thrombosis, but does not contribute to the pathogenesis of atherosclerosis and vascular remodeling. Published on behalf of the European Society of Cardiology. All rights reserved.
AIMS: Rho-associated coiled-coil containing kinase (ROCK)-2 is an important mediator of the actin cytoskeleton. Because changes in the actin cytoskeleton are critical for platelet function, we hypothesized that ROCK2 in platelets will play important role in thrombosis and can be potentially a target for therapeutic intervention in thromboembolic stroke. METHODS AND RESULTS: We generated platelet-specific ROCK2-deficient mice (ROCK2Plt-/-) from conditional ROCK2fl°x/fl°x and platelet factor (PF)-4-Cre transgenic mice. Platelets from ROCK2Plt-/- mice were less responsive to thrombin stimulation in terms of pseudopodia formation, collagen adhesion, and in the formation of homotypic and heterotypic aggregates. This corresponded to prolonged bleeding time and delayed vascular occlusion following vessel injury. To determine whether these changes in platelet function could affect thrombotic disease, we utilized a clot-embolic model of ischaemic stroke. When pre-formed clots from ROCK2Plt-/- mice were injected into the middle cerebral artery of control mice, cerebral blood flow recovery occurred more rapidly, leading to decreased cerebral injury and neurological deficits, compared to pre-formed clots from control mice. Interestingly, pre-formed clots from control mice produced similar degree of cerebral injury when injected into control or ROCK2Plt-/- mice, suggesting that platelet ROCK2 deficiency affects clot formation but not propagation. Indeed, in a non-thrombotic intra-filament MCA occlusion model of stroke, platelet ROCK2 deletion was not protective. Furthermore, ROCK2Plt-/- mice exhibit similar atherosclerosis severity and vascular remodeling as control mice. CONCLUSION: These findings indicate that platelet ROCK2 plays important role in platelet function and thrombosis, but does not contribute to the pathogenesis of atherosclerosis and vascular remodeling. Published on behalf of the European Society of Cardiology. All rights reserved.
Authors: Dmitri Nikitin; Seungbum Choi; Jan Mican; Martin Toul; Wi-Sun Ryu; Jiri Damborsky; Robert Mikulik; Dong-Eog Kim Journal: J Stroke Date: 2021-01-31 Impact factor: 6.967
Authors: Tadeu L Montagnoli; Jaqueline S da Silva; Susumu Z Sudo; Aimeé D Santos; Gabriel F Gomide; Mauro P L de Sá; Gisele Zapata-Sudo Journal: Cells Date: 2021-06-30 Impact factor: 7.666