Hypoxia Induces Permeability and Giant Cell Responses of Andes Virus-Infected Pulmonary Endothelial Cells by Activating the mTOR-S6K Signaling Pathway
Hypoxia Induces Permeability and Giant Cell Responses of Andes Virus-Infected Pulmonary Endothelial Cells by Activating the mTOR-S6K Signaling Pathway
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DOI：
10.1128/jvi.02103-13
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发表时间：
2013-12-01
影响因子：
5.4
通讯作者：
Mackow, Erich R.
中科院分区：
文献类型：
--
作者：
Gavrilovskaya, Irina N.;Gorbunova, Elena E.;Mackow, Erich R.
安第斯山脉病毒（ANDV）是一种南美汉他病毒，其引起高度致命的汉他病毒肺综合征（HPS），其特征在于缺氧、血小板减少和导致急性肺水肿的血管渗漏。ANDV感染人肺微血管和淋巴管内皮细胞（分别为MEC和LEC），并响应于血管内皮生长因子（VEGF）而非溶解性地增强内皮细胞间粘附连接的通透性。最近的研究结果还表明，ANDV导致巨内皮细胞的形成。在这里，我们证明，缺氧条件下单独增强ANDV感染的MEC和LEC的渗透性和巨细胞反应，通过激活mTOR信号通路。与非致病性图拉病毒（TULV）感染细胞相反，我们观察到ANDV感染的MEC和LEC暴露于缺氧条件下导致单层通透性增加3至6倍，并形成3倍至5倍正常大小的巨细胞。ANDV感染与缺氧条件相结合导致缺氧诱导因子1 α（HIF 1 α）介导的VEGF A、血管生成素4和EGLN 3转录反应增强。组成性mTOR信号传导通过S6K的磷酸化诱导巨细胞的形成，并且mTOR调节缺氧和VEGF A诱导的细胞应答。我们发现S6K在ANDV感染的、缺氧处理的MEC和LEC中过度磷酸化，并且雷帕霉素处理1小时抑制mTOR信号传导反应，并阻断ANDV感染的单层中的渗透性和巨细胞形成。这些发现表明ANDV感染和缺氧条件增强mTOR信号传导应答，导致内皮细胞通透性增强，并表明雷帕霉素在ANDV感染期间在治疗性稳定微血管和淋巴管内皮中的作用。
Andes virus (ANDV) is a South American hantavirus that causes a highly lethal hantavirus pulmonary syndrome (HPS) characterized by hypoxia, thrombocytopenia, and vascular leakage leading to acute pulmonary edema. ANDV infects human pulmonary microvascular and lymphatic endothelial cells (MECs and LECs, respectively) and nonlytically enhances the permeability of interendothelial cell adherence junctions in response to vascular endothelial growth factor (VEGF). Recent findings also indicate that ANDV causes the formation of giant endothelial cells. Here, we demonstrate that hypoxic conditions alone enhance permeability and giant cell responses of ANDV-infected MECs and LECs through activation of the mTOR signaling pathway. In contrast to infection of cells with nonpathogenic Tula virus (TULV), we observed that exposure of ANDV-infected MECs and LECs to hypoxic conditions resulted in a 3- to 6-fold increase in monolayer permeability and the formation of giant cells 3 x to 5 x normal size. ANDV infection in combination with hypoxic conditions resulted in the enhancement of hypoxia-inducible factor 1 alpha (HIF1 alpha)-directed VEGF A, angiopoietin 4, and EGLN3 transcriptional responses. Constitutive mTOR signaling induces the formation of giant cells via phosphorylation of S6K, and mTOR regulates hypoxia and VEGF A-induced cellular responses. We found that S6K was hyperphosphorylated in ANDV-infected, hypoxia-treated MECs and LECs and that rapamycin treatment for 1 h inhibited mTOR signaling responses and blocked permeability and giant cell formation in ANDV-infected monolayers. These findings indicate that ANDV infection and hypoxic conditions enhance mTOR signaling responses, resulting in enhanced endothelial cell permeability and suggest a role for rapamycin in therapeutically stabilizing the endothelium of microvascular and lymphatic vessels during ANDV infection.