Department of Life and Environmental Physics, HoriaHulubei National Institute of Physics and Nuclear Engineering, 077125 Magurele, Romania.
Faculty of Biology, University of Bucharest, 050095 Bucharest, Romania.
Int J Mol Sci. 2021 Jul 26;22(15):7957. doi: 10.3390/ijms22157957.
Besides the direct effects of radiations, indirect effects are observed within the surrounding non-irradiated area; irradiated cells relay stress signals in this close proximity, inducing the so-called radiation-induced bystander effect. These signals received by neighboring unirradiated cells induce specific responses similar with those of direct irradiated cells. To understand the cellular response of bystander cells, we performed a 2D gel-based proteomic study of the chondrocytes receiving the conditioned medium of low-dose irradiated chondrosarcoma cells. The conditioned medium was directly analyzed by mass spectrometry in order to identify candidate bystander factors involved in the signal transmission. The proteomic analysis of the bystander chondrocytes highlighted 20 proteins spots that were significantly modified at low dose, implicating several cellular mechanisms, such as oxidative stress responses, cellular motility, and exosomes pathways. In addition, the secretomic analysis revealed that the abundance of 40 proteins in the conditioned medium of 0.1 Gy irradiated chondrosarcoma cells was significantly modified, as compared with the conditioned medium of non-irradiated cells. A large cluster of proteins involved in stress granules and several proteins involved in the cellular response to DNA damage stimuli were increased in the 0.1 Gy condition. Several of these candidates and cellular mechanisms were confirmed by functional analysis, such as 8-oxodG quantification, western blot, and wound-healing migration tests. Taken together, these results shed new lights on the complexity of the radiation-induced bystander effects and the large variety of the cellular and molecular mechanisms involved, including the identification of a new potential actor, namely the stress granules.
除了辐射的直接效应外，在周围未照射区域也观察到间接效应；受照射的细胞在近距离内传递应激信号，诱导所谓的辐射诱导旁观者效应。这些未受照射的邻近细胞接收到的信号诱导出与直接受照射细胞相似的特定反应。为了了解旁观者细胞的细胞反应，我们对接受低剂量照射软骨肉瘤细胞条件培养基的软骨细胞进行了基于 2D 凝胶的蛋白质组学研究。通过质谱法直接分析条件培养基，以鉴定参与信号传递的候选旁观者因子。对旁观者软骨细胞的蛋白质组学分析突出了 20 个在低剂量下显著修饰的蛋白质斑点，涉及几种细胞机制，如氧化应激反应、细胞迁移和外泌体途径。此外，分泌组学分析显示，与非照射细胞的条件培养基相比，0.1Gy 照射软骨肉瘤细胞的条件培养基中 40 种蛋白质的丰度显著改变。在 0.1Gy 条件下，应激颗粒中涉及的大量蛋白质簇和几种参与细胞对 DNA 损伤刺激反应的蛋白质增加。这些候选物和细胞机制中的几个通过功能分析得到了证实，例如 8-oxodG 定量、western blot 和划痕愈合迁移试验。总之，这些结果揭示了辐射诱导旁观者效应的复杂性和所涉及的大量细胞和分子机制，包括鉴定一个新的潜在因子，即应激颗粒。
