FTY720 Ameliorates Acute Ischemic Stroke in Mice by Reducing Thrombo-Inflammation but Not by Direct Neuroprotection
FTY720 Ameliorates Acute Ischemic Stroke in Mice by Reducing Thrombo-Inflammation but Not by Direct Neuroprotection
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DOI：
10.1161/strokeaha.113.002880
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发表时间：
2013-11-01
期刊：
影响因子：
8.3
通讯作者：
Kleinschnitz, Christoph
中科院分区：
文献类型：
--
作者：
Kraft, Peter;Goeb, Eva;Kleinschnitz, Christoph
背景和目的淋巴细胞在急性缺血性中风的病理生理学中发挥着重要作用。淋巴细胞与内皮细胞和血小板的相互作用，称为血栓炎症，促进微血管功能障碍和继发性梗塞生长。 FTY720 是一种 1-磷酸鞘氨醇受体调节剂，可阻止淋巴细胞从淋巴器官流出，并已被证明可以减少缺血性神经变性；然而，其根本机制尚不清楚。我们研究了 FTY720 在脑缺血模型中的作用模式。 方法 在再灌注前立即用 FTY720 (1 mg/kg) 或媒介物处理的野生型和淋巴细胞缺陷型 Rag1(-/-) 小鼠中诱导短暂性大脑中动脉闭塞 (tMCAO)。 24小时后评估中风结果。通过流式细胞术对血液和脑中的免疫细胞进行计数。使用伊文思蓝染料分析血脑屏障的完整性。通过免疫组织化学和蛋白质印迹法测定血栓形成，并与脑灌注相关。结果在短暂大脑中动脉闭塞后的第1天和第3天，FTY720显着减少野生型小鼠中风的大小并改善功能结果。这种保护作用在淋巴细胞缺陷的 Rag1(-/-) 小鼠和培养的缺氧神经元中消失。 FTY720处理的野生型小鼠的脑血管系统中存在较少的淋巴细胞，这反过来又减少了血栓形成并增加了脑灌注。相比之下，FTY720 无法阻止大脑中动脉短暂闭塞后血脑屏障的破坏和跨内皮免疫细胞的运输。 结论 诱导淋巴细胞减少并同时减少微血管血栓形成是 FTY720 在中风中发挥作用的关键模式。相比之下，我们在 Rag1(-/-) 小鼠和培养神经元中的发现反对 FTY720 的直接神经保护作用。
Background and Purpose Lymphocytes are important players in the pathophysiology of acute ischemic stroke. The interaction of lymphocytes with endothelial cells and platelets, termed thrombo-inflammation, fosters microvascular dysfunction and secondary infarct growth. FTY720, a sphingosine-1-phosphate receptor modulator, blocks the egress of lymphocytes from lymphoid organs and has been shown to reduce ischemic neurodegeneration; however, the underlying mechanisms are unclear. We investigated the mode of FTY720 action in models of cerebral ischemia.Methods Transient middle cerebral artery occlusion (tMCAO) was induced in wild-type and lymphocyte-deficient Rag1(-/-) mice treated with FTY720 (1 mg/kg) or vehicle immediately before reperfusion. Stroke outcome was assessed 24 hours later. Immune cells in the blood and brain were counted by flow cytometry. The integrity of the blood-brain barrier was analyzed using Evans Blue dye. Thrombus formation was determined by immunohistochemistry and Western blot, and was correlated with cerebral perfusion.Results FTY720 significantly reduced stroke size and improved functional outcome in wild-type mice on day 1 and day 3 after transient middle cerebral artery occlusion. This protective effect was lost in lymphocyte-deficient Rag1(-/-) mice and in cultured neurons subjected to hypoxia. Less lymphocytes were present in the cerebral vasculature of FTY720-treated wild-type mice, which in turn reduced thrombosis and increased cerebral perfusion. In contrast, FTY720 was unable to prevent blood-brain barrier breakdown and transendothelial immune cell trafficking after transient middle cerebral artery occlusion.Conclusions Induction of lymphocytopenia and concomitant reduction of microvascular thrombosis are key modes of FTY720 action in stroke. In contrast, our findings in Rag1(-/-) mice and cultured neurons argue against direct neuroprotective effects of FTY720.