A novel role of hypoxia-inducible factor in cobalt chloride- and hypoxia-mediated expression of IL-8 chemokine in human endothelial cells
A novel role of hypoxia-inducible factor in cobalt chloride- and hypoxia-mediated expression of IL-8 chemokine in human endothelial cells
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DOI：
10.4049/jimmunol.177.10.7211
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发表时间：
2006-11-15
影响因子：
4.4
通讯作者：
Kalra, Vijay K.
中科院分区：
文献类型：
--
作者：
Kim, Kyoung S.;Rajagopal, Vikram;Kalra, Vijay K.
组织低氧血症在多种病理性疾病中很常见，包括镰状细胞病和心肌梗塞中的血管闭塞。人们发现，肺损伤期间和血管内皮炎症部位的白细胞数量增加。在本研究中，我们使用人肺微血管内皮细胞和人真皮微血管内皮永生化细胞系来描述缺氧和CoCl2（缺氧模拟物）诱导IL-8表达的细胞信号传导机制，以及后者在多形核中性粒细胞趋化中的作用。我们发现缺氧和 CoCl2 诱导的 IL-8 mRNA 和蛋白表达涉及 PI3K/Akt 和 p38 MAPK 的激活，但不涉及 MEK 激酶。对一些与 M-8 启动子相关的转录因子的分析表明，缺氧和 CoCl2 增加了缺氧诱导因子 1 α (HIF-1 α)、NF-κ B 和 AP-1 的 DNA 结合活性。此外，我们发现缺氧和 CoCl2 诱导的 IL-8 表达需要激活 HIF，如下所示：1）EMSA； 2) 使用 HIF-1 α 结合位点突变的 IL-8 启动子报告构建体进行转染研究； 3) HIF-1α小干扰RNA和R59949减弱IL-8表达； 4)通过用HIF-脯氨酰羟化酶-2小干扰RNA转染或HIF-1α过表达来增强IL-8表达； 5) 染色质免疫沉淀分析。此外，由于IL-8的释放，来自缺氧处理的内皮细胞的条件培养基增强了中性粒细胞的趋化性。这些数据表明血管内皮中缺氧诱导的 IL-8 转录激活信号涉及 PI3K/Akt、p38 MAPK 和 HIF-1 α。抑制 HIF-1a 的药物可能会改善病理疾病中与缺氧相关的炎症。
Tissue hypoxemia is common in several pathological diseases, including vaso-occlusion in sickle cell disease and myocardial infarction. One finds increased presence of leukocytes during lung injury and at sites of inflammation in vascular endothelium. In this study, we used human pulmonary microvascular endothelial cells and human dermal microvascular endothelial immortalized cell line to delineate the cellular signaling mechanism of hypoxia- and CoCl2 (a mimetic of hypoxia)-induced IL-8 expression, and the latter's role in chemotaxis of polmorphonuclear neutrophils. We show that hypoxia- and CoCl2-induced IL-8 mRNA and protein expression involved activation of PI3K/Akt and p38 MAPK, but not MEK kinase. Analysis of some transcription factors associated with M-8 promoter revealed that hypoxia and CoCl2 increased DNA-binding activity of hypoxia-inducible factor-1 alpha (HIF-1 alpha), NF-kappa B, and AP-1. In addition, we show that hypoxia- and CoCl2-induced IL-8 expression requires activation of HIF as demonstrated by the following: 1) EMSA; 2) transfection studies with IL-8 promoter reporter constructs with mutation in HIF-1 alpha binding site; 3) attenuation of IL-8 expression by both HIF-1 alpha small interfering RNA and R59949; 4) augmentation of IL-8 expression by either transfection with HIF-prolyl hydroxylase-2 small interfering RNA or overexpression of HIF-1 alpha; and 5) chromatin immunoprecipitation analysis. Moreover, conditioned medium from hypoxia-treated endothelial cells augmented chemotaxis of neutrophils, due to release of IL-8. These data indicate that hypoxia-induced signaling in vascular endothelium for transcriptional activation of IL-8 involves PI3K/Akt, p38 MAPK, and HIF-1 alpha. Pharmacological agents, which inhibit HIF-1a, may possibly ameliorate inflammation associated with hypoxia in pathological diseases.