Zacharek Alex, Chen Jieli, Cui Xu, Li Ang, Li Yi, Roberts Cynthia, Feng Yifan, Gao Qi, Chopp Michael
Department of Neurology, Henry Ford Health Sciences Center, Detroit, Michigan, USA.
J Cereb Blood Flow Metab. 2007 Oct;27(10):1684-91. doi: 10.1038/sj.jcbfm.9600475. Epub 2007 Mar 14.
Bone marrow stromal cells (MSCs) increase vascular endothelial growth factor (VEGF) expression and promote angiogenesis after stroke. Angiopoietin-1 (Ang1) and its receptor Tie2 mediate vascular integrity and angiogenesis as does VEGF and its receptors. In this study, we tested whether MSC treatment of stroke increases Ang1/Tie2 expression, and whether Ang1/Tie2 with VEGF/ vascular endothelial growth factor receptor 2 (VEGFR2) (Flk1), in combination, induced by MSCs enhances angiogenesis and vascular integrity. Male Wistar rats were subjected to middle cerebral artery occlusion (MCAo) and treated with or without MSCs. Marrow stromal cell treatment significantly decreased blood-brain barrier (BBB) leakage and increased Ang1, Tie2, and occludin (a tight junction protein) expression in the ischemic border compared with MCAo control. To further test the mechanisms of MSC-induced angiogenesis and vascular stabilization, cocultures of MSCs with mouse brain endothelial cells (MBECs) or astrocytes were performed. Supernatant derived from MSCs cocultured with MBECs significantly increased MBEC expression of Ang1/Tie2 and Flk1 compared with MBEC alone. Marrow stromal cells cocultured with astrocytes also significantly increased astrocyte VEGF and Ang1/Tie2 expression compared with astrocyte culture alone. Conditioned media from MSCs alone, and media from cocultures of MSCs with astrocytes or MBECs, all significantly increased capillary tube-like formation of MBEC compared with control Dulbecco's modified Eagle's medium media. Inhibition of Flk1 and/or Ang1 significantly decreased MSC-induced MBEC tube formation. Knockdown of Tie2 expression in MBECs significantly inhibited MSC-induced tube formation. Our data indicate MSC treatment of stroke promotes angiogenesis and vascular stabilization, which is at least partially mediated by VEGF/Flk1 and Ang1/Tie2.
骨髓基质细胞（MSCs）可增加血管内皮生长因子（VEGF）的表达，并在中风后促进血管生成。血管生成素-1（Ang1）及其受体Tie2与VEGF及其受体一样，介导血管完整性和血管生成。在本研究中，我们测试了MSCs治疗中风是否会增加Ang1/Tie2的表达，以及MSCs诱导的Ang1/Tie2与VEGF/血管内皮生长因子受体2（VEGFR2，即Flk1）联合是否能增强血管生成和血管完整性。雄性Wistar大鼠接受大脑中动脉闭塞（MCAo）处理，并给予或不给予MSCs治疗。与MCAo对照组相比，骨髓基质细胞治疗显著降低了血脑屏障（BBB）渗漏，并增加了缺血边界区Ang1、Tie2和闭合蛋白（一种紧密连接蛋白）的表达。为了进一步测试MSCs诱导血管生成和血管稳定的机制，进行了MSCs与小鼠脑内皮细胞（MBECs）或星形胶质细胞的共培养。与单独的MBECs相比，与MBECs共培养的MSCs的上清液显著增加了MBECs中Ang1/Tie2和Flk1的表达。与单独的星形胶质细胞培养相比，与星形胶质细胞共培养的骨髓基质细胞也显著增加了星形胶质细胞VEGF和Ang1/Tie2的表达。与对照的杜氏改良 Eagle培养基相比，单独的MSCs条件培养基以及MSCs与星形胶质细胞或MBECs共培养的培养基均显著增加了MBECs的毛细血管样形成。抑制Flk1和/或Ang1显著降低了MSCs诱导的MBECs管形成。敲低MBECs中Tie2的表达显著抑制了MSCs诱导的管形成。我们的数据表明，MSCs治疗中风可促进血管生成和血管稳定，这至少部分是由VEGF/Flk1和Ang1/Tie2介导的。
