Screening and preliminary analysis of differentially expressed miRNAs in gastric cancer cell-derived exosomes induced by Helicobacter pylori / 中华微生物学和免疫学杂志

ABSTRACT

Objective:To investigate the differentially expressed microRNAs (miRNAs) in human gastric carcinoma SGC-7901 cell-derived exosomes induced by Helicobacter pylori ( H. pylori), providing new clues for further elucidating the carcinogenic mechanism of H. pylori. Methods:Ultracentrifugation and exosome extraction kit were used to extract the exosomes released by the H. pylori-stimulated and negative control group, and transmission electron microscope(TEM), nanoparticle tracking analysis(NTA) and Western blot experiments were employed to identify exosomes. Then, exosomes were labeled with the fluorescent dye PKH67 and co-cultured with THP-1-derived macrophages. The internalization of exosomes by macrophages was observed by laser confocal fluorescent microscopy. Additionally, miRNA microarray chips were performed to detect the differentially expressed miRNAs of exosomes from the two groups of cells. Real-time fluorescence quantitative PCR (qRT-PCR) was used to verify the expression of four differentially expressed miRNAs. Furthermore, the target genes and their functions as well as the possible signal pathways involved of partial differentially expressed miRNAs were predicted and analyzed by bioinformatics software. Differentially expressed miR-382-5p was labeled by Cy3 to observe whether it could be transferred to macrophages through exosomes. The expression of phenotype molecule CD206 and the cytokines TNF-α, IL-6 and IL-10 in miR-382-5p mimic-transfected macrophages were analyzed by qRT-PCR and ELISA, and the proportion of cells expressing CD206 and HLA-DR was analyzed by flow cytometry. Results:The extracted exosomes were consistent with exosome morphology and highly expressed the surface marker proteins CD9, CD63 and TSG101. After co-culturing with THP-1 derived macrophages for 12 h, the exosomes could be internalized by macrophages. Compared with the control group, there were 130 up-regulated miRNAs and 111 down-regulated miRNAs in the H. pylori-stimulated group. Bioinformatic analysis showed that the potential target genes of partial differentially expressed miRNAs were mainly involved in the regulation of PI3K-AKT, NF-κB, JAK-STAT, stem cell pluripotency and other inflammation and tumor-related pathways. miR-382-5p could be transferred to macrophages through exosomes, and induced the expression of M2-type phenotype molecule CD206 and cytokines IL-10 in macrophages, while inhibited the expression of TNF-α and IL-6 and increased the proportion of CD206 high HLA-DR low cells. Conclusions:H. pylori treatment caused a significant change in the expression level of exosome miRNAs in SGC-7901 cells. Bioinformatics analysis demonstrated that the prospective targets of these differentially expressed miRNAs might play an important role in the regulation of inflammation and tumor-related signaling pathways. miR-382-5p might induce the M2-type polarization of macrophages.