AUTHOR=Tridandapani Susheela , Cremer Thomas J., Fatehchand Kavin , Shah Prexy , Gillette Devyn , Patel Hemal , Marsh Rachel L., Besecker Beth Y., Rajaram Murugesan V., Kanneganti Thirumala-Devi , Schlesinger Larry , Butchar Jonathan P. TITLE=MiR-155 Induction by Microbes/Microbial Ligands Requires NF-κB-Dependent de novo Protein Synthesis JOURNAL=Frontiers in Cellular and Infection Microbiology VOLUME=2 YEAR=2012 URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2012.00073 DOI=10.3389/fcimb.2012.00073 ISSN=2235-2988 ABSTRACT=

MiR-155 regulates numerous aspects of innate and adaptive immune function. This miR is induced in response to Toll-like receptor ligands, cytokines, and microbial infection. We have previously shown that miR-155 is induced in monocytes/macrophages infected with Francisella tularensis and suppresses expression of the inositol phosphatase SHIP to enhance activation of the PI3K/Akt pathway, which in turn promotes favorable responses for the host. Here we examined how miR-155 expression is regulated during infection. First, our data demonstrate that miR-155 can be induced through soluble factors of bacterial origin and not the host. Second, miR-155 induction is not a direct effect of infection and it requires NF-κB signaling to up-regulate fos/jun transcription factors. Finally, we demonstrate that the requirement for NF-κB-dependent de novo protein synthesis is globally shared by microbial ligands and live bacteria. This study provides new insight into the complex regulation of miR-155 during microbial infection.