MiR-155 Induction by Microbes/Microbial Ligands Requires NF-?B-Dependent de novo Protein Synthesis.

MiR-155 Induction by Microbes/Microbial Ligands Requires NF-?B-Dependent de novo Protein Synthesis.

Front Cell Infect Microbiol. 2012;2:73

Authors: Cremer TJ, Fatehchand K, Shah P, Gillette D, Patel H, Marsh RL, Besecker BY, Rajaram MV, Cormet-Boyaka E, Kanneganti TD, Schlesinger LS, Butchar JP, Tridandapani S

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-?B signaling to up-regulate fos/jun transcription factors. Finally, we demonstrate that the requirement for NF-?B-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.

PMID: 22919664 [PubMed]

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