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Abstract：
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.
摘要：
除了辐射的直接影响，在周围的非照射区域内观察到间接效应；受照射的细胞在这个近距离传递应激信号，诱导所谓的辐射诱导的旁观者效应。由邻近的未照射的细胞接收的这些信号诱导与直接照射的细胞相似的特异性应答。为了了解旁观者细胞的细胞反应，我们对接受低剂量照射的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输的候选旁观者因子。旁观者软骨细胞的蛋白质组学分析突出了20个蛋白质点，这些蛋白质点在低剂量下被显著修饰，牵涉到几种细胞机制，如氧化应激反应，细胞运动性,和外泌体途径。此外,分泌组学分析显示，0.1Gy照射的软骨肉瘤细胞的条件培养基中40种蛋白质的丰度被显著修饰，与未照射细胞的条件培养基相比。在0.1Gy条件下，参与应激颗粒的一大簇蛋白质和参与细胞对DNA损伤刺激的反应的几种蛋白质增加。通过功能分析证实了这些候选物和细胞机制中的一些，如8-oxodG定量，westernblot,和伤口愈合迁移测试。一起来看,这些结果为辐射引起的旁观者效应的复杂性以及所涉及的各种细胞和分子机制提供了新的启示，包括识别新的潜在演员，即应力颗粒。
