Identification of MyD88 as a novel target of miR‐155, involved in negative regulation of Helicobacter pylori ‐induced inflammation

MicroRNA‐155 (miR‐155) has been implicated as a central regulator of the immune system. We have previously reported that miR‐155 negatively regulates Helicobacter pylori ( H. pylori )‐induced inflammation, but the molecular mechanism of miR‐155 regulating the inflammation is not fully clear. Here, we identified myeloid differentiation protein 88 (MyD88) as a target gene of miR‐155, and found that miR‐155 decreased MyD88 expression at the protein but not the mRNA message level, suggesting that the miR‐155‐mediated inhibition is a post‐transcriptional event. Furthermore, the overexpression of miR‐155 led to significantly reduced IL‐8 production induced by H. pylori infection. Thus, we have demonstrated that miR‐155 can negatively regulate inflammation by targeting a key adaptor molecule MyD88 in inflammatory pathways.