From the Section of Hematology-Oncology, Department of Pediatrics, Baylor College of Medicine Houston, TX (T.A.F.).
Center for Translational Research on Inflammatory Diseases, Michael E. DeBakey Veterans Affairs Medical Center, Houston, TX (T.A.F., S.-H.H., Q.D., C.V., M.A.C., S.P.M.).
Stroke. 2018 Oct;49(10):2536-2540. doi: 10.1161/STROKEAHA.118.022888.
Background and Purpose- VWF (von Willebrand factor) strings mediate spontaneous platelet adhesion in the vascular lumen, which may lead to microthrombi formation and contribute to stroke pathology. However, the mechanism of VWF string attachment at the endothelial surface is unknown. We tested the novel hypothesis that VWF strings are tethered to the endothelial surface through an interaction between extracellular vimentin and the A2 domain of VWF. We further explored the translational value of blocking this interaction in a model of ischemic stroke. Methods- Human endothelial cells and pressurized cerebral arteries were stimulated with histamine to elicit VWF string formation. Recombinant proteins and antibodies were used to block VWF string formation. Mice underwent transient middle cerebral artery occlusion with reperfusion. Just before recanalization, mice were given either vehicle or A2 protein (recombinant VWF A2 domain) to disrupt the vimentin/VWF interaction. Laser speckle contrast imaging was used to monitor cortical perfusion. Results- Pressurized cerebral arteries produced VWF strings following histamine stimulation, which were reduced in arteries from Vim KO (vimentin knockout) mice. VWF string formation was significantly reduced in endothelial cells incubated with A2 protein or antivimentin antibodies. Lastly, A2 protein treatment significantly improved cortical reperfusion after middle cerebral artery occlusion. Conclusions- We provide the first direct evidence of cerebral VWF strings and demonstrate that extracellular vimentin significantly contributes to VWF string formation via A2 domain binding. Lastly, we show that pharmacologically targeting the vimentin/VWF interaction through the A2 domain can promote improved reperfusion after ischemic stroke. Together, these studies demonstrate the critical role of VWF strings in stroke pathology and offer new therapeutic targets for treatment of ischemic stroke.
背景与目的-VWF（血管性血友病因子）串介导血管腔内自发性血小板黏附，可能导致微血栓形成，并有助于中风病理。然而，VWF 串在血管内皮表面附着的机制尚不清楚。我们检验了一个新的假说，即 VWF 串通过细胞外波形蛋白与 VWF 的 A2 结构域之间的相互作用而被固定在血管内皮表面。我们进一步在缺血性中风模型中探索了阻断这种相互作用的转化价值。方法-用组胺刺激人内皮细胞和加压脑动脉，引发 VWF 串形成。使用重组蛋白和抗体来阻断 VWF 串形成。对小鼠进行短暂性大脑中动脉闭塞再灌注。在再通之前，给小鼠注射载体或 A2 蛋白（重组 VWF A2 结构域）以破坏波形蛋白/VWF 相互作用。使用激光散斑对比成像监测皮质灌注。结果-组胺刺激后加压脑动脉产生 VWF 串，Vim KO（波形蛋白敲除）小鼠的动脉中 VWF 串减少。在孵育有 A2 蛋白或抗波形蛋白抗体的内皮细胞中，VWF 串形成明显减少。最后，A2 蛋白治疗显著改善大脑中动脉闭塞后的皮质再灌注。结论-我们提供了脑 VWF 串的首个直接证据，并证明细胞外波形蛋白通过 A2 结构域结合显著促进 VWF 串形成。最后，我们表明通过 A2 结构域靶向波形蛋白/VWF 相互作用可以促进缺血性中风后的再灌注。综上所述，这些研究表明 VWF 串在中风病理中的关键作用，并为缺血性中风的治疗提供了新的治疗靶点。
