Hallahan D, Clark E T, Kuchibhotla J, Gewertz B L, Collins T
Department of Radiation and Cellular Oncology, University of Chicago, Illinois 60637, USA.
Biochem Biophys Res Commun. 1995 Dec 26;217(3):784-95. doi: 10.1006/bbrc.1995.2841.
The mechanism of the x-ray-mediated inflammatory response in normal tissues is unknown. To determine whether leukocyte infiltration into irradiated tissue is regulated by adhesion molecule expression, we quantified the synthesis of glycoproteins that participate in inflammation. We found that E-selectin is synthesized in a time-dependent manner following exposure to doses as low as 0.5 Gy. Northern blot analysis demonstrated that E-selectin mRNA expression increased at 2 h after x-irradiation and increased expression required no de novo protein synthesis. Transcription of the promoter region of E-selectin (-578 to +35) was transiently induced following x-irradiation, whereas deletion of the NFkB binding site eliminated x-ray induction. Electrophoretic mobility gel shift analysis confirmed increased binding of nuclear proteins from irradiated endothelial cells to the NFkB binding sequence from the E-selectin promoter. Nuclear protein binding to the NFkB binding sequence was altered by antibodies to the p50 and p65 components of NFkB. These data demonstrate that E-selectin expression does not require cytokine synthesis, but involves NFkB activation.
正常组织中X射线介导的炎症反应机制尚不清楚。为了确定白细胞浸润到受照射组织中是否受黏附分子表达的调节，我们对参与炎症的糖蛋白合成进行了定量。我们发现，暴露于低至0.5 Gy的剂量后，E-选择素以时间依赖性方式合成。Northern印迹分析表明，X射线照射后2小时E-选择素mRNA表达增加，且表达增加不需要从头合成蛋白质。X射线照射后短暂诱导E-选择素启动子区域（-578至+35）的转录，而删除NFkB结合位点则消除了X射线诱导作用。电泳迁移率凝胶移位分析证实，受照射内皮细胞核蛋白与E-选择素启动子的NFkB结合序列的结合增加。针对NFkB的p50和p65成分的抗体改变了核蛋白与NFkB结合序列的结合。这些数据表明，E-选择素的表达不需要细胞因子合成，但涉及NFkB激活。
