RRC ID 50467
Author Shiratsuchi A, Nitta M, Kuroda A, Komiyama C, Gawasawa M, Shimamoto N, Tuan TQ, Morita T, Aiba H, Nakanishi Y.
Title Inhibition of Phagocytic Killing of Escherichia coli in Drosophila Hemocytes by RNA Chaperone Hfq.
Journal J Immunol
Abstract An RNA chaperone of Escherichia coli, called host factor required for phage Qβ RNA replication (Hfq), forms a complex with small noncoding RNAs to facilitate their binding to target mRNA for the alteration of translation efficiency and stability. Although the role of Hfq in the virulence and drug resistance of bacteria has been suggested, how this RNA chaperone controls the infectious state remains unknown. In the present study, we addressed this issue using Drosophila melanogaster as a host for bacterial infection. In an assay for abdominal infection using adult flies, an E. coli strain with mutation in hfq was eliminated earlier, whereas flies survived longer compared with infection with a parental strain. The same was true with flies deficient in humoral responses, but the mutant phenotypes were not observed when a fly line with impaired hemocyte phagocytosis was infected. The results from an assay for phagocytosis in vitro revealed that Hfq inhibits the killing of E. coli by Drosophila phagocytes after engulfment. Furthermore, Hfq seemed to exert this action partly through enhancing the expression of σ(38), a stress-responsive σ factor that was previously shown to be involved in the inhibition of phagocytic killing of E. coli, by a posttranscriptional mechanism. Our study indicates that the RNA chaperone Hfq contributes to the persistent infection of E. coli by maintaining the expression of bacterial genes, including one coding for σ(38), that help bacteria evade host immunity.
Volume 197(4)
Pages 1298-307
Published 2016-8-15
DOI 10.4049/jimmunol.1501953
PII jimmunol.1501953
PMID 27357148
MeSH Animals Blotting, Western Disease Models, Animal Drosophila / microbiology* Escherichia coli / pathogenicity* Escherichia coli Infections / microbiology* Escherichia coli Proteins / metabolism* Gene Expression Regulation, Bacterial / physiology* Hemocytes / microbiology Host Factor 1 Protein / metabolism* Phagocytosis / physiology Reverse Transcriptase Polymerase Chain Reaction Virulence / physiology
IF 4.718
Drosophila Oregon R