MDM2-p53 介导 miR-181c-3p/LIF 轴调节低剂量率辐射诱导的人 B 淋巴细胞 DNA 损伤。
MDM2-p53 mediate a miR-181c-3p/LIF axis to regulate low dose-rate radiation-induced DNA damage in human B lymphocytes.
机构信息
Institute of Cytology and Genetics, The Hengyang Key Laboratory of Cellular Stress Biology, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical School, University of South China, Hengyang, Hunan 421001, China.
The Second Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan 421001, China.
出版信息
Ecotoxicol Environ Saf. 2024 Jan 15;270:115848. doi: 10.1016/j.ecoenv.2023.115848. Epub 2023 Dec 21.
PURPOSE
Prolonged exposure to low dose-rate radiation (LDRR) is of growing concern to public health. Recent evidences indicates that LDRR causes deleterious health effects and is closely related to miRNAs. The aim of our study is to investigate the relationship between miRNAs and DNA damage caused by LDRR.
MATERIALS AND METHODS
In this study, we irradiated C57BL/6J mice with 12.5μGy/h dose of γ ray emitted from uranium ore for 8 h a day for 120 days at a total dose of 12 mGy, and identified differentially expressed miRNAs from the mice long-term exposed to LDRR through isolating serum RNAs, constructing small RNA library, Illumina sequencing. To further investigate the role of differential miRNA under LDRR，we first built DNA damage model in Immortal B cells irradiated with 12.5μGy/h dose of γ ray for 28 days at a total dose of 9.4 mGy. Then, we chose the highly conserved miR-181c-3p among 12 miRNA and its mechanism in alleviating DNA damage induced by LDRR was studied by transfection, quantitative PCR, luciferase assay, and Western blot.
RESULTS AND CONCLUSIONS
We have found that 12 differentially expressed miRNAs including miR-181c-3p in serum isolated from irradiated mice. Analysis of GO and KEGG indicated that target genes of theses 12 miRNA enriched in pathways related to membrane, protein binding and cancer. Long-term exposure to LDRR induced upregulation of gamma-H2A histone family member X (γ-H2AX) expression, a classical biomarker for DNA damage in B cells. miR-181c-3p inhibited Leukemia inhibitory factor (LIF) expression via combining its 3'UTR. LIF, MDM2, p53, and p-p53-s6 were upregulated after exposure to LDRR. In irradiated B cells, Transfection of miR-181c-3p reduced γ-H2AX expression and suppressed LIF and MDM2 protein levels, whereas p-p53-s6 expression was increased. As expected, the effect of LIF inhibition on irradiated B cells was similar to miR-181c-3p overexpression. Our results suggest that LDRR alters miRNA expression and induces DNA damage. Furthermore, miR-181c-3p can alleviate LDRR-induced DNA damage via the LIF/MDM2/p-p53-s6 pathway in human B lymphocytes. This could provide the basis for prevention and treatment of LDRR injury.
目的
低剂量率辐射（LDRR）的长期暴露对公共健康的影响越来越受到关注。最近的证据表明，LDRR 会造成有害的健康影响，并且与 miRNAs 密切相关。本研究旨在探讨 miRNA 与 LDRR 引起的 DNA 损伤之间的关系。
材料与方法
在这项研究中，我们通过从小鼠血清中分离 RNA，构建小 RNA 文库，进行 Illumina 测序，从长期暴露于 LDRR 的小鼠中鉴定出差异表达的 miRNAs。为了进一步研究 LDRR 下差异 miRNA 的作用，我们首先用 12.5μGy/h 剂量的γ射线照射 Immortal B 细胞，每天照射 8 小时，共照射 28 天，总剂量为 9.4mGy，建立 DNA 损伤模型。然后，我们选择在 12 个 miRNA 中高度保守的 miR-181c-3p，并通过转染、定量 PCR、荧光素酶测定和 Western blot 研究其在缓解 LDRR 引起的 DNA 损伤中的机制。
结果与结论
我们发现 12 种差异表达的 miRNAs，包括来自照射小鼠血清中的 miR-181c-3p。GO 和 KEGG 分析表明，这些 miRNA 的靶基因富集在与膜、蛋白质结合和癌症相关的途径中。长期暴露于 LDRR 会导致 B 细胞中 γ-H2AX 表达的上调，γ-H2AX 是 DNA 损伤的经典生物标志物。miR-181c-3p 通过结合其 3'UTR 抑制白血病抑制因子（LIF）的表达。LDRR 暴露后，LIF、MDM2、p53 和 p-p53-s6 表达上调。在照射的 B 细胞中，miR-181c-3p 的转染降低了 γ-H2AX 的表达，并抑制了 LIF 和 MDM2 蛋白水平，而 p-p53-s6 的表达增加。正如预期的那样，LIF 抑制对照射的 B 细胞的作用类似于 miR-181c-3p 的过表达。我们的结果表明，LDRR 改变了 miRNA 的表达并诱导了 DNA 损伤。此外，miR-181c-3p 可以通过 LIF/MDM2/p-p53-s6 通路减轻 LDRR 诱导的 DNA 损伤，这为预防和治疗 LDRR 损伤提供了依据。
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