Activator protein 1 shows a biphasic induction and transcriptional activity after low dose X-irradiation in EA.hy.926 endothelial cells

• Published in: Autoimmunity (Chur, Switzerland) Switzerland), 2009-01, Vol.42 (4), p.343-345
• Main Authors: Rödel, Franz, Keilholz, Ludwig, Herrmann, Martin, Weiss, Christian, Frey, Benjamin, Voll, Reinhard, Gaipl, Udo, Rödel, Claus
• Format: Article
• Language: English
• Subjects: Dose-Response Relationship, Radiation; Electrophoretic Mobility Shift Assay; Endothelial Cells - metabolism; Endothelial Cells - radiation effects; Gene Expression - radiation effects; Gene Expression Regulation - radiation effects; Humans; Transcription Factor AP-1 - genetics; Transcription Factor AP-1 - metabolism; Transcription Factor AP-1 - radiation effects
• ISSN: 0891-6934; 1607-842X
• DOI: 10.1080/08916930902831597

Low dose radiotherapy (LD-RT) is known to exert an anti-inflammatory effect. The underlying molecular mechanisms, however, are still a matter of actual research. We have recently shown that LD-RT of stimulated EA.hy.926 endothelial cells (EC) resulted in a biphasic DNA-binding and transcriptional activity of NF-κB in parallel with a biphasic course of leukocyte adhesion. Here we report, that following low dose X-irradiation, an increased activator protein 1 (AP-1) DNA-binding activity was observed in EC with a first relative maximum at 0.3 Gy as analysed by electrophoretic mobility shift assay. AP-1 activity then decreased at doses between 0.5 and 1 Gy and subsequently increased again at 3 Gy. This biphasic profile was confirmed on the transcriptional level by an AP-1 specific chemoluminescence reporter assay. In conclusion, the discontinuous dose response of AP-1 activation may add a further facet to the plethora of mechanisms contributing to the anti-inflammatory efficacy of LD-RT.