Identification and bioinformatic function analysis of differentially expressed miRNAs in the exosomes secreted from BEP2D cells irradiated by γ-rays / 中华放射医学与防护杂志

ABSTRACT

Objective@# To identify the differentially expressed miRNAs in the exosomes secreted from γ-ray irradiated cells and provide new clues in disclosing the mechanisms of radiation-induced bystander effects.@*Methods@#The human bronchial epithelial cells (BEP2D) were irradiated with 60Co γ-rays, and the exosomes were collected by ultracentrifugation from the culture medium of 2 Gy-irradiated cells and non-irradiated control. The exosomes were identified by an electron microscopy. The miRNA microarray technique was used to analyze the miRNA expression profiles in the exosomes. qRT-PCR was used to verify the miRNAs expression. The functional pathways of miRNAs targeting genes were predicted by informatic analysis using the databases of TargetScan, miRanda, GO and KEGG.@*Results@#Sixteen miRNA with significantly increased expression (P<0.05) were identified in the exosomes of BEP2D cells at 4 h post-2 Gy irradiation as compared with the non-irradiated control cells, among which miR-100-5p, miR-1246, miR-29b-3p, and miR-7-5p were further confirmed to be unregulated by qRT-PCR assay (P<0.05). Meanwhile, the expression changes of above-mentioned four miRNAs were also investigated in the irradiated cells. The data indicated the expression was significantly increased at 2 h post-2 Gy irradiation for the miR-100-5p, miR-1246, miR-29b-3p in addition to miR-7-5p. However, all these four miRNAs were downregulated in the cells at 4 h post-irradiation and then gradually recovered. Bioinformatics analysis showed that the targeted genes of these differentially expressed miRNAs might participate in the biological processes and signal pathways of cell adhesion, mTOR signal pathway, chromatin modification, HR and NHEJ pathways of DNA repair and so on.@*Conclusions@# Radiation-inducible miRNAs have been identified in the exosomes from the irradiated BEP2D cells. The target genes of these miRNAs play roles in a series of important biological processes and functional pathways, which provides new clues in elucidating the mechanisms of radiation-induced bystander effects.