TRANSCRIPTIONAL REGULATION OF THE INTERCELLULAR-ADHESION MOLECULE-1 GENE BY INFLAMMATORY CYTOKINES IN HUMAN ENDOTHELIAL-CELLS - ESSENTIAL ROLES OF A VARIANT NF-KAPPA-B SITE AND P65 HOMODIMERS
TRANSCRIPTIONAL REGULATION OF THE INTERCELLULAR-ADHESION MOLECULE-1 GENE BY INFLAMMATORY CYTOKINES IN HUMAN ENDOTHELIAL-CELLS - ESSENTIAL ROLES OF A VARIANT NF-KAPPA-B SITE AND P65 HOMODIMERS
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DOI：
10.1074/jbc.270.2.933
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发表时间：
1995-01-13
影响因子：
4.8
通讯作者：
PARKS, TP
中科院分区：
文献类型：
--
作者：
LEDEBUR, HC;PARKS, TP
细胞间粘附分子-1 （ICAM-1）在炎症部位的内皮细胞上显著上调，并参与白细胞附着和外渗。先前，我们已经表明，ICAM-1基因在人脐静脉内皮细胞（HUVECs）中的表达受肿瘤坏死因子- α (tnf - α)的转录调节(Wertheimer， S. J., Myers， C. L., Wallace， R. W., and Parks， T. P. (1992) J. Biol。化学，267,12030-12035)。在目前的研究中，发现tnf - α诱导的转录仅在翻译起始位点上游40和41个碱基对的两个位点上启动。对ICAM-1基因5'调控区域的缺失分析显示，在瞬时转染试验中，92个碱基对序列既必要又足够使tnf - α对相关的荧光素酶报告基因产生反应。这个tnf - α反应区包含一个变异的NF-kappa P位点，位于-187至-178，当突变时，完全消除了tnf - α、白细胞介素-1 β和脂多糖对ICAM-1启动子的激活。两个可诱导的核蛋白复合物结合到ICAM-1 kappa B位点，鉴定为NF-kappa D p65同型二聚体和p65/p50异源二聚体。在HUVECs中，p65而非p50的过表达会以kappa B位点依赖的方式反激活ICAM-1启动子。此外，p65介导的转录激活被p50的共表达所抑制。我们的研究结果表明，HUVECs中ICAM-1启动子的细胞因子激活可能严重依赖于p65同型二聚体与变异kappa B位点的结合。
Intercellular adhesion molecule-1 (ICAM-1) is greatly up-regulated on endothelial cells at sites of inflammation and is involved in leukocyte attachment and extravasation. Previously, we had shown that the ICAM-1 gene expression in human umbilical vein endothelial cells (HUVECs) was transcriptionally regulated by tumor necrosis factor-alpha (TNF-alpha) (Wertheimer, S. J., Myers, C. L., Wallace, R. W., and Parks, T. P. (1992) J. Biol. Chem. 267, 12030-12035). In the present investigation, TNF-alpha-induced transcription was found to be initiated exclusively at two sites, 40 and 41 base pairs upstream of the translation start site, Deletion analysis of the 5' regulatory region of the ICAM-1 gene revealed a 92-base pair sequence which was both necessary and sufficient to confer TNF-alpha responsiveness to a linked luciferase reporter gene in transient transfection assays, This TNF-alpha-responsive region contained a variant NF-kappa P site at -187 to -178, which when mutated, completely abolished ICAM-1 promoter activation by TNF-alpha, interleukin-1 beta, and lipopolysaccharide. Two inducible nuclear protein complexes bound to the ICAM-1 kappa B site and were identified as the NF-kappa D p65 homodimer and p65/p50 heterodimer. Overexpression of p65, but not p50, transactivated the ICAM-1 promoter in a kappa B site-dependent manner in HUVECs. In addition, p65-mediated transactivation was suppressed by co-expression of p50. Our results suggest that cytokine activation of the ICAM-1 promoter in HUVECs may critically depend on p65 homodimers binding to a variant kappa B site.