Evolution of miR-155 and its probable targets:MST1R, Adam10, andCD9genes expression levels in adults and children gastritis patients withH. pyloriinfection

Introduction H. pylori accounts for the main factor of gastric cancer which contributes to an immune response with the promotion of inflammation. Recently, the effect of miRNAs on the prognosis of diseases is gaining the attraction of investigators. Herein, we studied the expression levels of miR-155 and its identified targets ( MST1R, Adam10 , and CD9 ) along with miR-155 expression correlation with virulence factors of H. pylori ( vacA and cag genes ), H. pylori colonization, and inflammation, in patients’ candidates for gastric endoscopy due to gastritis. Methods in this study total of 50 and 26 biopsy samples were taken from adults and children respectively. Biochemical and molecular identification of samples was performed using culture and PCR of ureC, 16sRNA , along with amplification of vacA and cagA genes for pathogenicity of bacteria. The qRT-PCR was carried out using STEM-LOOP RT-PCR (dye-based) for the evaluation of miR-155 expression level and Adam10, CD9 , and MST1R expression levels. All Real-Time PCR reactions were carried out in triplicate and data analysis was conducted using REST. Results A total of 30 out of 17 biopsy samples in adults and children were positive for H. pylori in both PCR and culture, respectively. The expression level of miR-155 is closely related to the H. pylori infection and the down-regulation of CD9 , and MST1R genes in H. pylori (+) samples compared to H. pylori (-) in adults’ biopsy (p=0.0001). Although, there wasn’t any relation between cagA and vacA genes with the expression of miR-155 in evaluated biopsy samples in both adults and children. i Conclusion This study for the first time revealed that the expression of MST1R, CD9 , and adam10 genes was relatively related to the expression of miR-155, and indicated that the miR-155 overexpression promoted the poor prognosis of H. pylori infection in adults.