Gap junction communication and the propagation of bystander effects induced by microbeam irradiation in human fibroblast cultures: the impact of radiation quality.
Gap junction communication and the propagation of bystander effects induced by microbeam irradiation in human fibroblast cultures: the impact of radiation quality.
复制标题
DOI：
10.1667/rr3111.1
复制
发表时间：
2013-10
影响因子：
3.4
通讯作者：
Murakami T
中科院分区：
文献类型：
--
作者：
Autsavapromporn N;Suzuki M;Funayama T;Usami N;Plante I;Yokota Y;Mutou Y;Ikeda H;Kobayashi K;Kobayashi Y;Uchihori Y;Hei TK;Azzam EI;Murakami T
了解低或高线性能量转移（LET）辐射的低剂量/低通量旁观者效应的机制与放射治疗和辐射防护相关。在这里，我们研究了缝隙连接细胞间通讯（GJIC）的作用，在传播的压力效应在汇合正常人成纤维细胞培养，其中只有0.036-0.144%的细胞在人口中被穿越的主要辐射轨道。在加入或不加入GJIC抑制剂18-α-大黄酸（阿加）的情况下，用5.35keV X射线（LET ~6 keV/μ m）、18.3MeV/u碳离子（LET ~103 keV/μ m）、13 MeV/u氖离子（LET ~380 keV/μm）或11.5MeV/u氩离子（LET ~ 1, 260 keV/μm）微束对融合细胞进行不同剂量照射。在37°C下孵育4小时后，对细胞进行传代培养并测定微核（MN）形成。根据初级辐射靶向的细胞比例，诱导的细胞比例高于预期，并且任何辐射源的效应均以剂量依赖性方式发生。有趣的是，MN形成的重离子微束照射在没有阿加高于在其存在下，在高的平均吸收剂量。与此相反，有或没有阿加暴露于X射线微束照射的细胞培养物中没有显着差异。这表明抑制GJIC抑制了暴露于高LET辐射的旁观者细胞中MN形成的增强，但对低LET辐射没有抑制作用。从5.35 keV X射线照射培养物收获的生长培养基的旁观者细胞受体经历了以过量微核形成形式表现的应激。总之，这些结果支持连接通讯和分泌因子参与辐射诱导的应激向旁观者细胞的传播。他们强调了辐射质量和剂量在观察到的效应中的重要作用。
Understanding the mechanisms underlying the bystander effects of low doses/low fluences of low- or high-linear energy transfer (LET) radiation is relevant to radiotherapy and radiation protection. Here, we investigated the role of gap-junction intercellular communication (GJIC) in the propagation of stressful effects in confluent normal human fibroblast cultures wherein only 0.036–0.144% of cells in the population were traversed by primary radiation tracks. Confluent cells were exposed to graded doses from monochromatic 5.35 keV X ray (LET ~6 keV/μm), 18.3 MeV/u carbon ion (LET ~103 keV/μm), 13 MeV/u neon ion (LET ~380 keV/μm) or 11.5 MeV/u argon ion (LET ~1,260 keV/μm) microbeams in the presence or absence of 18-α-glycyrrhetinic acid (AGA), an inhibitor of GJIC. After 4 h incubation at 37°C, the cells were subcultured and assayed for micronucleus (MN) formation. Micronuclei were induced in a greater fraction of cells than expected based on the fraction of cells targeted by primary radiation, and the effect occurred in a dose-dependent manner with any of the radiation sources. Interestingly, MN formation for the heavy-ion microbeam irradiation in the absence of AGA was higher than in its presence at high mean absorbed doses. In contrast, there were no significant differences in cell cultures exposed to X-ray microbeam irradiation in presence or absence of AGA. This showed that the inhibition of GJIC depressed the enhancement of MN formation in bystander cells from cultures exposed to high-LET radiation but not low-LET radiation. Bystander cells recipient of growth medium harvested from 5.35 keV X-irradiated cultures experienced stress manifested in the form of excess micronucleus formation. Together, the results support the involvement of both junctional communication and secreted factor(s) in the propagation of radiation-induced stress to bystander cells. They highlight the important role of radiation quality and dose in the observed effects.