ABSTRACT
Objective To study the changes in miRNAs expression in the exosomes of human umbilical vein endothelial cells(HUVECs) after 60 Co γ-rays expose using microRNA(miRNA) chips and bioinformatics techniques so as to provide new clues to the mechanism of radiation-induced vascular tissue injury and its bystander effects.Methods HUVECs exosomes were collected in the control and 4 Gy irradiated cells by ultra-high-speed centrifugation,and further confirmed using transmission electron microscopy (TEM) and Western blotting of exosomes biomarkers.miRNA microarray was used to analyze miRNA expression profiles of exosomes and cells.Also,real-time quantitative PCR(qRT-PCR) was used to verify differentially expressed miRNAs,and the miRDB and TargetScan were performed to predict the target genes of the differentially expressed miRNAs.Bioinformatics analysis was performed using DAVID,KEGG and other online tools.Results Compared with the control exosomes from non-irradiated HUVECs,miRNA microarray analysis revealed that 5 up-regulated,and 13 down-regulated miRNAs were identified in the exosomes from HUVECs at 0.5 h after 4 Gy-irradiation,and 16 up-regulated and 5 down-regulated miRNAs at 2 h after 4 Gy-irradiation.Moreover,38 and 85 miRNAs were differentially expressed respectively in the HUVECs at 0.5 h and 2 h after radiation.The difference was statistically significant(P<0.01).The results of bioinformatics showed that these miRNAs might exert the radiation-induced bystander effect (RIBE) by regulating MAPK signal pathways,RAS and PI3K-Akt signal pathways.Conclusion The ionizing radiation injury significantly alters the components and expression levels of exosomal miRNAs,which play important roles in regulating the signal pathways in response to radiation.