Identification and characterization of miRNAs involved in cold acclimation of zebrafish ZF4 cells

MicroRNAs (miRNAs) play vital roles in various biological processes by leading to mRNA cleavage or translational repression, and are also involved in multiple stress conditions. However, the detailed roles of miRNAs in cold acclimation in fish are still unclear. In the present study, high-throughput sequencing was performed to identify miRNAs from 6 small RNA libraries from the zebrafish embryonic fibroblast ZF4 cells under control (28°C, 30 days) and cold-acclimation (18°C, 30 days) conditions. A total of 414 miRNAs, 349 known and 65 novel, were identified. Among those miRNAs, 24 (19 known and 5 novel) were up-regulated, and 23 (9 known and 14 novel) were down-regulated in cold acclimated cells. The Gene Ontology (GO) and Kyoto Encyclopaedia of Genes and Genomes (KEGG) enrichment analyses indicated that the known differentially expressed miRNAs (DE-miRNA) are involved in cold acclimation by regulation of phosphorylation, cell junction, intracellular signal transduction, ECM-receptor interaction and so on. Moreover, dre-miR-100-3p inhibitor or dre-miR-16b mimics could protect ZF4 cells under cold stress, indicating the involvement of miRNA in cold acclimation. In summary, the present data show that miRNAs are closely involved in cold acclimation in fish and provide information for further understanding of the roles of miRNAs in cold acclimation. Overall design: ZF4 cells were cultured at 28 °C as control and at 18 °C for 30 days, seperately. Each condition has three biological replica.