Enhanced Susceptibility to Citrobacter rodentium Infection in MicroRNA-155-Deficient Mice
Clare S., John V., Walker AW., Hill JL., Abreu-Goodger C., Hale C., Goulding D., Lawley TD., Mastroeni P., Frankel G., Enright AJ., Vigorito E., Dougan G.
ABSTRACTMicroRNAs (miRNAs) are small noncoding molecules that control gene expression posttranscriptionally, with microRNA-155 (miR-155) one of the first to be implicated in immune regulation. Here, we show that miR-155-deficient mice are less able to eradicate a mucosalCitrobacter rodentiuminfection than wild-type C57BL/6 mice. miR-155-deficient mice exhibited prolonged colonization associated with a higherC. rodentiumburden in gastrointestinal tissue and spread into systemic tissues. Germinal center formation and humoral immune responses againstC. rodentiumwere severely impaired in infected miR-155-deficient mice. A similarly susceptible phenotype was observed in μMT mice reconstituted with miR-155-deficient B cells, indicating that miR-155 is required intrinsically for mediating protection against this predominantly luminal bacterial pathogen.