Department of Radiotherapy and Oncology, University of Frankfurt, Frankfurt am Main, Germany.
Radiother Oncol. 2010 Nov;97(2):346-51. doi: 10.1016/j.radonc.2010.01.013. Epub 2010 Feb 17.
This study aimed to characterize a link between X-linked inhibitor of apoptosis protein (XIAP) expression, apoptosis induction, Nuclear Factor kappa B (NF-κB) activity and the anti-inflammatory properties of low-dose ionising-radiation (LD-RT).
EA.hy.926 endothelial cells (ECs) were irradiated with doses ranging from 0.3 to 3Gy, and subsequently stimulated by TNF-α, and XIAP expression was either detected by immunoblotting or TaqMan-PCR. Apoptosis was quantified by AnnexinV staining or by caspase 3/7 activity assays. NF-κB transcriptional activity was analysed by a luciferase reporter assay, secretion of Transforming Growth Factor beta 1 (TGF-β(1)) and adhesion of peripheral blood mononuclear cells (PBMC) to EC were quantified using ELISA and adhesion assays.
LD-RT of the activated EA.Hy.926 EC induces XIAP expression in a discontinuous manner with a relative maximum at 0.5Gy and 3Gy which parallels a discontinuity in apoptosis induction and caspase 3/7 activity. siRNA-mediated attenuation of XIAP resulted in an increased rate of apoptosis, a hampered NF-κB transcriptional activity and a diminished secretion of TGF-β(1). As compared to control-siRNA treated cells, adhesion of PBMC to EC was increased in XIAP depleted EA.Hy.926 EC.
The modulation of apoptosis, NF-κB activity and TGF-β(1) by XIAP in irradiated and subsequent stimulated EC contributes to an impaired PBMC/EC adhesion and to the anti-inflammatory properties of LD-RT.
本研究旨在描述 X 连锁凋亡抑制蛋白（XIAP）表达、细胞凋亡诱导、核因子 kappa B（NF-κB）活性与低剂量电离辐射（LD-RT）的抗炎特性之间的联系。
用 0.3 至 3Gy 的剂量辐照 EA.hy.926 内皮细胞（EC），随后用 TNF-α 刺激，通过免疫印迹或 TaqMan-PCR 检测 XIAP 的表达。通过 AnnexinV 染色或 caspase 3/7 活性测定来定量细胞凋亡。通过荧光素酶报告基因测定分析 NF-κB 转录活性，通过 ELISA 和黏附测定来定量转化生长因子β 1（TGF-β1）的分泌和外周血单核细胞（PBMC）与 EC 的黏附。
激活的 EA.Hy.926 EC 的 LD-RT 以不连续的方式诱导 XIAP 表达，在 0.5Gy 和 3Gy 时相对最大，这与细胞凋亡诱导和 caspase 3/7 活性的不连续性相平行。用 siRNA 介导的 XIAP 衰减导致细胞凋亡率增加、NF-κB 转录活性受阻和 TGF-β1 分泌减少。与对照 siRNA 处理的细胞相比，XIAP 耗尽的 EA.Hy.926 EC 中 PBMC 与 EC 的黏附增加。
在辐照后的 EC 中，XIAP 对细胞凋亡、NF-κB 活性和 TGF-β1 的调节有助于受损的 PBMC/EC 黏附，并有助于 LD-RT 的抗炎特性。
