Repression of SPI2 transcription by nitric oxide-producing, IFNγ-activated macrophages promotes maturation of Salmonella phagosomes

Bruce D. McCollister, Travis J. Bourret, Ronald Gill, Jessica Jones-Carson, Andrés Vázquez-Torres

Research output: Contribution to journalArticle

51 Citations (Scopus)

Abstract

By remodeling the phagosomal membrane, the type III secretion system encoded within the Salmonella pathogenicity island-2 (SPI2) helps Salmonella thrive within professional phagocytes. We report here that nitric oxide (NO) generated by IFNγ-activated macrophages abrogates the intracellular survival advantage associated with a functional SPI2 type III secretion system. NO congeners inhibit overall expression of SPI2 effectors encoded both inside and outside the SPI2 gene cluster, reflecting a reduced transcript level of the sensor kinase SsrA that governs overall SPI2 transcription. Down-regulation of SPI2 expression in IFNγ-treated macrophages does not seem to be the result of global NO cytotoxicity, because transcription of the housekeeping rpoD sigma factor remains unchanged, whereas the expression of the hmpA-encoded, NO-metabolizing flavohemoprotein is stimulated. Because of the reduced SPI2 expression, Salmonella-containing vacuoles interact more efficiently with compartments of the late endosomal/lysosomal system in NO-producing, IFNγ-treated macrophages. These findings demonstrate that inhibition of intracellular SPI2 transcription by NO promotes the interaction of Salmonella phagosomes with the degradative compartments required for enhanced antimicrobial activity. Transcriptional repression of a type III secretion system that blocks phagolysosome biogenesis represents a novel mechanism by which NO mediates resistance of IFNγ-activated phagocytes to an intracellular pathogen. JEM

Original languageEnglish
Pages (from-to)625-635
Number of pages11
JournalJournal of Experimental Medicine
Volume202
Issue number5
DOIs
StatePublished - Sep 5 2005
Externally publishedYes

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Genomic Islands
Phagosomes
Salmonella
Nitric Oxide
Macrophages
Phagocytes
Sigma Factor
Housekeeping
Multigene Family
Vacuoles
Phosphotransferases
Down-Regulation

All Science Journal Classification (ASJC) codes

  • Immunology

Cite this

Repression of SPI2 transcription by nitric oxide-producing, IFNγ-activated macrophages promotes maturation of Salmonella phagosomes. / McCollister, Bruce D.; Bourret, Travis J.; Gill, Ronald; Jones-Carson, Jessica; Vázquez-Torres, Andrés.

In: Journal of Experimental Medicine, Vol. 202, No. 5, 05.09.2005, p. 625-635.

Research output: Contribution to journalArticle

McCollister, Bruce D. ; Bourret, Travis J. ; Gill, Ronald ; Jones-Carson, Jessica ; Vázquez-Torres, Andrés. / Repression of SPI2 transcription by nitric oxide-producing, IFNγ-activated macrophages promotes maturation of Salmonella phagosomes. In: Journal of Experimental Medicine. 2005 ; Vol. 202, No. 5. pp. 625-635.
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