Department of Immunology and Parasitology, School of Medicine, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu, 807-8555, Japan; Department of Clinical Laboratory, The Fourth Hospital of Hebei Medical University, No. 169 Tian Shan Street, Shijiazhuang, 050035, China.
Department of Radiobiology and Hygiene Management, Institute of Industrial Ecological Sciences Group for Environmental Evaluation, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu, 807-8555, Japan.
Dev Comp Immunol. 2021 Sep;122:104124. doi: 10.1016/j.dci.2021.104124. Epub 2021 May 8.
DNA damage-induced cellular senescence is involved in aging. We reported previously that p53 mice subjected to irradiation at a young age exhibited an increased number of splenic lymphocytes in the S and G2/M phases. However, the detailed nature of splenic disorders in these mice is not fully understood. In this study, we investigated the effects on molecules in splenocytes, especially on senescence factors after early exposure of mice to radiation. Mice, 8- (young) or 17-, 30-, and 41-week-old (old) p53 were subjected to 3-Gy whole-body irradiation. Splenocytes were prepared at 56 weeks of age. Immunoblot showed that irradiation at 8 weeks enhanced the expression and phosphorylation of p53, cyclin-dependent kinase 2, cell division cycle 6, and the MDM2 proto-oncogene in splenocytes. However, these molecules were not affected by irradiation at 17, 30, and 41 weeks of age. Similarly, irradiation at 8, but not 17, 30, or 41 weeks, induced phosphorylation of IKKα, NF-κB inhibitor alpha, and p65. Electrophoretic mobility shift assay demonstrated that active forms of NF-κB were increased. In addition, enzyme-linked immunosorbent assay showed that lipopolysaccharide-induced IL-6 production was enhanced in splenocytes of mice irradiated at 8 weeks. ATP levels were increased in splenocytes of mice irradiated at 8, but not 17, 30, or 41 weeks. CDK2 expression and p65 phosphorylation were induced in CD45R/B220 cells from irradiated mice. Overall, irradiation induced a NF-κB-related immune response in the spleen with an increase in senescence marker proteins, such as CDKs and IL-6, which are known to be typical senescence-associated secretory phenotype factors related to stresses, such as DNA damage.
DNA 损伤诱导的细胞衰老与衰老有关。我们之前报道过，年轻时接受辐射照射的 p53 小鼠表现出脾脏淋巴细胞在 S 和 G2/M 期的数量增加。然而，这些小鼠脾脏紊乱的详细性质尚未完全了解。在这项研究中，我们研究了辐射早期暴露对脾细胞中分子的影响，特别是对衰老相关分泌表型因子的影响。将 8 周（年轻）或 17 周、30 周和 41 周（老年）p53 小鼠进行 3Gy 全身照射。在 56 周龄时制备脾细胞。免疫印迹显示，8 周照射增强了脾细胞中 p53、细胞周期蛋白依赖性激酶 2、细胞分裂周期 6 和 MDM2 原癌基因的表达和磷酸化。然而，这些分子不受 17、30 和 41 周照射的影响。同样，8 周照射诱导 IKKα、NF-κB 抑制剂 α 和 p65 的磷酸化，但 17、30 或 41 周照射则没有。电泳迁移率变动分析显示 NF-κB 的活性形式增加。此外，酶联免疫吸附试验显示，8 周照射的小鼠脾细胞中脂多糖诱导的 IL-6 产生增强。8 周照射的小鼠脾细胞中 ATP 水平升高，但 17、30 或 41 周照射则没有。照射小鼠的 CD45R/B220 细胞中 CDK2 表达和 p65 磷酸化增加。总之，辐射诱导了脾脏中与 NF-κB 相关的免疫反应，增加了衰老标志物蛋白，如 CDKs 和 IL-6，这些蛋白已知是与 DNA 损伤等应激相关的典型衰老相关分泌表型因子。
