Background/aims: MicroRNAs (miRNAs) regulate gene expression. We assess miRNA regulation by Helicobacter pylori infection and elucidate their role in H. pylori-infected gastric epithelial cells.
Methods: The relationship between miRNA expression and DNA methylation was examined. Cells were treated with the nuclear factor-kappaB (NF-κB) inhibitor Bay 11-7082 to determine the relationship between miRNA expression and NF-κB signal transduction.
Results: In the negative control cells infected with H. pylori 26695, the expression of six miRNAs was increased, whereas the expression of five miRNAs was decreased. The expression of upregulated miRNAs was increased when the host cells were treated with H. pylori and an NF-κB inhibitor. miR-127-5p, -155, and -181 were associated with increased interleukin 6 (IL-6) secretion in H. pylori infected cells treated with anti-miRNA. The expression of miR-155, -127-5p, -195, -216, -206, and -488 increased by approximately 3-fold following treatment with the methylation inhibitor Aza.
Conclusions: We found novel miRNAs in H. pylori-infected negative control cells using miRNA microarrays. Upregulated miRNA expression was inversely related to the transcription of NF-κB. miR-195 and miR-488 appear to play a pivotal role in controlling IL-6 activity in H. pylori infection. miRNA expression in H. pylori infection was affected by methylation.
Keywords: Cytokines; Helicobacter pylori; MicroRNAs; NF-kappa B; Negative control cell lines.