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Abstract：
Intercellular adhesion molecule 1 (ICAM-1) is a central cell adhesion molecule for retinal transendothelial migration of the leukocytes in non-infectious posterior uveitis. Inhibiting ICAM1 gene transcription reduces induction of ICAM-1 in inflamed retinal endothelium. Based on published literature implicating transcription factor ETS-1 as an activator of ICAM1 gene transcription, we investigated the effect of ETS-1 blockade on ICAM-1 levels in cytokine-stimulated human retinal endothelial cells. We first examined ICAM1 and ETS1 transcript expression in human retinal endothelial cells exposed to tumor necrosis factor-alpha (TNF-α) or interleukin-1beta (IL-1β). ICAM1 and ETS1 transcripts were increased in parallel in primary human retinal endothelial cell isolates (n = 5) after a 4-hour stimulation with TNF-α or IL-1β (p ≤ 0.012 and ≤ 0.032, respectively). We then assessed the effect of ETS-1 blockade by small interfering (si)RNA on cellular ICAM1 transcript and membrane-bound ICAM-1 protein. ETS1 transcript was reduced by greater than 90% in cytokine-stimulated and non-stimulated human retinal endothelial cell monolayers following a 48-hour treatment with two ETS-1-targeted siRNA, in comparison to negative control non-targeted siRNA (p ≤ 0.0002). The ETS-1 blockade did not reduce ICAM1 transcript expression nor levels of membrane-bound ICAM-1 protein, rather it increased both for a majority of siRNA-treatment and cytokine-stimulation conditions (p ≤ 0.018 and ≤ 0.004, respectively). These unexpected findings indicate that ETS-1 blockade increases ICAM-1 transcript and protein levels in human retinal endothelial cells. Thus ETS-1-targeting would be expected to promote rather than inhibit retinal transendothelial migration of leukocytes in non-infectious posterior uveitis.
摘要：
细胞间粘附分子1（ICAM-1）是非感染性后葡萄膜炎中白细胞经视网膜内皮迁移的中枢细胞粘附分子。抑制ICAM-1基因转录降低了ICAM-1在发炎的视网膜内皮中的诱导。根据已发表的文献，暗示转录因子ETS-1是ICAM1基因转录的激活因子，我们研究了ETS-1阻断对细胞因子刺激的人视网膜内皮细胞ICAM-1水平的影响.我们首先检查了暴露于肿瘤坏死因子-α（TNF-α）或白介素-1β（IL-1β）的人视网膜内皮细胞中的ICAM1和ETS1转录本表达。用TNF-α或IL-1β刺激4小时后，原代人视网膜内皮细胞分离株（n=5）的ICAM1和ETS1转录物平行增加（分别为p≤0.012和≤0.032）。然后，我们评估了小干扰（si）RNA阻断ETS-1对细胞ICAM1转录本和膜结合ICAM-1蛋白的影响。用两种ETS-1靶向siRNA处理48小时后，在细胞因子刺激和非刺激的人视网膜内皮细胞单层中，ETS1转录物减少了90％以上。与阴性对照非靶向siRNA相比（p≤0.0002）。ETS-1阻断并没有降低ICAM1转录物的表达，也没有降低膜结合ICAM-1蛋白的水平，相反,它在大多数siRNA治疗和细胞因子刺激条件下都增加(分别为p≤0.018和≤0.004).这些意外发现表明ETS-1阻断增加了人视网膜内皮细胞中的ICAM-1转录物和蛋白质水平。因此,预期ETS-1靶向在非感染性后葡萄膜炎中促进而不是抑制白细胞的视网膜跨内皮迁移。
