Environmental Health Sciences and Research Bureau, Health Canada, ON, Canada.
Mutat Res. 2011 Jun 17;722(2):131-9. doi: 10.1016/j.mrgentox.2010.02.012. Epub 2010 Feb 25.
Benzo(a)pyrene (BaP) is a mutagenic and carcinogenic environmental contaminant. Metabolic activation of BaP is required for it to exert its mutagenic effects. Metabolism occurs via BaP interaction with the aryl hydrocarbon receptor (AHR) resulting in induction of phase 1 enzymes. Exposure to BaP is expected to cause differential regulation of AHR-responsive genes as well as pathways responding to DNA damage induced by its metabolites. MicroRNAs (miRNAs) are short non-coding molecules that control mRNA levels and protein translation. MiRNA regulation may also be affected by chemical insult. Here we investigate the correlation between hepatic mRNA and miRNA response to BaP in vivo. Mature male mice were orally exposed to 3 daily doses of 150mg/kg BaP. DNA microarrays were used to profile gene and miRNA expression in the liver 4 and 24h following the final dose. Despite widespread changes in gene expression (>400 genes) in pathways consistent with the known effects of BaP, we found no changes in miRNA. This was confirmed on two microarray platforms and by qRT-PCR. Analysis of positive controls (2 distinct reference pools) indicated that the Agilent technology could identify differences in miRNA. The effects of sample storage at -80°C were also compared. We found little effect of prolonged freezing on the technical correlation between samples or on differential expression. Our results are consistent with the lack of response of miRNA in rodent liver to dioxin, another potent AHR-agonist. We conclude that hepatic miRNA in vivo is not directly responsive to BaP exposure.
苯并[a]芘（BaP）是一种致突变和致癌的环境污染物。BaP 发挥其致突变作用需要代谢激活。代谢通过 BaP 与芳烃受体（AHR）相互作用发生，导致 1 期酶的诱导。预计 BaP 的暴露会导致 AHR 反应基因以及其代谢物诱导的 DNA 损伤反应途径的差异调节。microRNAs（miRNAs）是控制 mRNA 水平和蛋白质翻译的短非编码分子。化学刺激也可能影响 miRNA 的调节。在这里，我们研究了体内 BaP 对肝 mRNA 和 miRNA 反应的相关性。成熟雄性小鼠经口暴露于 3 次 150mg/kg BaP 的每日剂量。在最后一次剂量后 4 和 24 小时，用 DNA 微阵列分析肝脏中的基因和 miRNA 表达谱。尽管在与 BaP 已知作用一致的途径中观察到基因表达的广泛变化（>400 个基因），但我们没有发现 miRNA 的变化。这在两个微阵列平台和 qRT-PCR 上得到了证实。阳性对照（2 个不同的参考池）的分析表明，安捷伦技术可以识别 miRNA 的差异。还比较了 -80°C 下样本储存的影响。我们发现长时间冷冻对样品之间的技术相关性或差异表达的影响很小。我们的结果与 miRNA 对另一种强效 AHR 激动剂二恶英在啮齿动物肝脏中的反应缺乏一致。我们得出结论，体内肝 miRNA 对 BaP 暴露没有直接反应。
