Gene expression profiling in human fibroblast after low-LET irradiation

Exposure to radiation provokes cellular responses controlled in part by gene expression networks. MicroRNAs (miRNAs) are small non-coding RNAs which mostly regulate gene expression by degrading the messages or inhibiting translation. Here we investigated changes in miRNA expression patterns after low (0.1 Gy) and high (2.0 Gy) doses of X-ray in human fibroblasts. At early (0.5 h) and late (6 and 24 h) time points irradiation caused qualitative and quantitative differences in the down-regulation of miRNA levels including miR-92b 137 660 and 656. A transient up-regulation of miRNAs was observed after 2 h post-irradiation following high doses of radiation including miR-558 and 662. MicroRNA levels were inversely correlated with targets from mRNA and proteomic profiling after 2.0 Gy of radiation. MicroRNAs miR-579 608 548-3p and 585 are noted for targeting genes involved in radioresponsive mechanisms such as cell cycle checkpoint and apoptosis. We suggest here a model in which miRNAs may act as hub regulators of specific cellular responses immediately down-regulated so as to stimulate DNA repair mechanisms followed by up-regulation involved in suppressing apoptosis for cell survival. Taken together miRNAs may mediate signaling pathways in sequential fashion in response to radiation and may serve as biodosimetric markers of radiation exposure. Overall design: The gene expression patterns in human fibroblasts after 2.0 Gy of low-LET radiation was determined at 2 and 24 hrs post-irradiation time in technical triplicates. Control non-irradiated samples were also prepared in triplicates.

辐射暴露诱发由基因表达网络部分调控的细胞反应。微RNA（miRNA）是一类小型非编码RNA，主要通过降解信息或抑制翻译来调节基因表达。在本研究中，我们调查了在人类成纤维细胞中，低剂量（0.1 Gy）和高剂量（2.0 Gy）X射线照射后miRNA表达模式的改变。在早期（0.5小时）和晚期（6小时和24小时）时间点，照射导致miRNA水平的下调发生质和量的差异，包括miR-92b、137、660和656。在高剂量辐射（包括miR-558和662）照射后2小时，观察到miRNA的短暂上调。在2.0 Gy辐射后，miRNA水平与mRNA和蛋白质组学分析的目标呈负相关。miR-579、608、548-3p和585等miRNA因其靶向涉及放射反应机制（如细胞周期检查点和细胞凋亡）的基因而受到关注。我们在此提出一种模型，其中miRNA可能作为特定细胞反应的枢纽调节因子，立即下调，以刺激DNA修复机制，随后上调，参与抑制细胞凋亡以促进细胞存活。综合来看，miRNA可能在辐射响应中按顺序介导信号通路，并可能作为辐射暴露的生物剂量学标记。总体设计：在2.0 Gy低LET辐射照射后2小时和24小时，以技术重复三份的方式确定了人类成纤维细胞的基因表达模式。还准备了三份非照射对照样本。