重组组织型纤溶酶原激活剂通过血管内皮生长因子介导的内皮细胞内吞作用,在小鼠脑缺血期间短暂增强血脑屏障通透性。
Recombinant tissue-type plasminogen activator transiently enhances blood-brain barrier permeability during cerebral ischemia through vascular endothelial growth factor-mediated endothelial endocytosis in mice.
作者信息
Suzuki Yasuhiro, Nagai Nobuo, Yamakawa Kasumi, Muranaka Yoshinori, Hokamura Kazuya, Umemura Kazuo
机构信息
School of Pharmaceutical Sciences, Ohu University, Koriyama, Japan.
Department of Pharmacology, Hamamatsu University School of Medicine, Hamamatsu, Japan.
出版信息
J Cereb Blood Flow Metab. 2015 Dec;35(12):2021-31. doi: 10.1038/jcbfm.2015.167. Epub 2015 Jul 29.
Recombinant tissue-type plasminogen activator (rt-PA) modulates cerebrovascular permeability and exacerbates brain injury in ischemic stroke, but its mechanisms remain unclear. We studied the involvement of vascular endothelial growth factor (VEGF)-mediated endocytosis in the increase of blood-brain barrier (BBB) permeability potentiated by rt-PA after ischemic stroke. The rt-PA treatment at 4 hours after middle cerebral artery occlusion induced a transient increase in BBB permeability after ischemic stroke in mice, which was suppressed by antagonists of either low-density lipoprotein receptor families (LDLRs) or VEGF receptor-2 (VEGFR-2). In immortalized bEnd.3 endothelial cells, rt-PA treatment upregulated VEGF expression and VEGFR-2 phosphorylation under ischemic conditions in an LDLR-dependent manner. In addition, rt-PA treatment increased endocytosis and transcellular transport in bEnd.3 monolayers under ischemic conditions, which were suppressed by the inhibition of LDLRs, VEGF, or VEGFR-2. The rt-PA treatment also increased the endocytosis of endothelial cells in the ischemic brain region after stroke in mice. These findings indicate that rt-PA increased BBB permeability via induction of VEGF, which at least partially mediates subsequent increase in endothelial endocytosis. Therefore, inhibition of VEGF induction may have beneficial effects after thrombolytic therapy with rt-PA treatment after stroke.
重组组织型纤溶酶原激活剂(rt-PA)可调节脑血管通透性并加重缺血性脑卒中的脑损伤,但其机制尚不清楚。我们研究了血管内皮生长因子(VEGF)介导的内吞作用在rt-PA加重缺血性脑卒中后血脑屏障(BBB)通透性增加中的作用。在小鼠大脑中动脉闭塞后4小时给予rt-PA治疗,可导致缺血性脑卒中后BBB通透性短暂增加,这一现象可被低密度脂蛋白受体家族(LDLRs)拮抗剂或VEGF受体-2(VEGFR-2)拮抗剂所抑制。在永生化的bEnd.3内皮细胞中,rt-PA治疗在缺血条件下以LDLR依赖的方式上调VEGF表达和VEGFR-2磷酸化。此外,rt-PA治疗在缺血条件下增加了bEnd.3单层细胞的内吞作用和跨细胞转运,这一作用可被抑制LDLRs、VEGF或VEGFR-2所抑制。rt-PA治疗还增加了小鼠脑卒中后缺血脑区内皮细胞的内吞作用。这些发现表明,rt-PA通过诱导VEGF增加BBB通透性,而VEGF至少部分介导了随后内皮细胞内吞作用的增加。因此,抑制VEGF的诱导可能对脑卒中后rt-PA溶栓治疗具有有益作用。