miRNA-155对氟虫腈作用下斑马鱼ZF4细胞存活的影响

microRNA（miRNA）是一类长约20～24 nt的非编码单链小分子RNA. 环境毒理学研究表明，当生物暴露于环境化学物质时，会引起相关miRNA表达发生变化，进而调节基因的表达. 农药氟虫腈是一种苯基吡唑类杀虫剂，能影响斑马鱼中miR-155的正常表达，但尚未见异位表达的miR-155对斑马鱼细胞影响的研究. 本研究明确了异位表达的miR-155对氟虫腈作用下斑马鱼胚胎细胞ZF4存活的影响. 结果显示，氟虫腈处理ZF4细胞72 h的IC50值为39.05 μmol/L，瞬时转染miR-155 mimic，显著降低了ZF4细胞氟虫腈暴露的存活率.同时real-time PCR结果显示,其潜在靶基因cyb561d2表达显著降低；而转染miR-155 inhibitor，抑制细胞内源性的miR-155则可显著增强ZF4细胞抵抗氟虫腈细胞毒性的能力，同时cyb561d2表达则显著增高.以上结果表明，miR-155参与氟虫腈毒理学效应，其表达量的高低可以影响氟虫腈作用下ZF4细胞的存活率，而其可能的途径之一是通过潜在靶基因cyb561d2的表达调控来实现. 因此，miR-155可作为氟虫腈环境毒性的潜在的生物标志物，有望成为致癌环境化学物质对生物体作用机制研究的新途径.

Effects of miRNA-155 on Zebrafish ZF4 Cell Survival under Fipronil Stress

microRNA (miRNA) is a class of non-coding RNAs in small sizes (20～24 nt). Environmental toxicological studies showed that the expression level of specific miRNAs changed during the exposure to environmental chemicals in many species, causing the expression alteration of their target genes. Fipronil is a phenylpyrazole insecticide known to influence the expression of miR-155 in zebrafish. This study evaluated the effects of the ectopic expression of miR-155 on the survival of zebrafish embryo ZF4 cells under fipronil stress. MTT assays indicated that the fipronil IC50 was 39.05 μmol/L at 72 h for ZF4 cells. The cell survival was significantly decreased under fipronil stress when transfected with miR-155 mimic. The expression of a target gene cyb561d2 was significantly reduced. When miR-155 inhibitor was transfected into ZF4 cells to suppress endogenous miR-155, the cells exerted the resistance to the fiproni cytotoxicity. The expression of cyb561d2 was also significantly increased. The results indicated that miR-155 was involved in the toxicological effects of fipronil and influenced the survival of ZF4 cells. The gene cyb561d2 could be a functional target for delivering such effects.