Document Detail


Phagosomal retention of Francisella tularensis results in TIRAP/Mal-independent TLR2 signaling.
MedLine Citation:
PMID:  19889726     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
TLR2 plays a central role in the activation of innate immunity in response to Ft, the causative agent of tularemia. We reported previously that Ft LVS elicited strong, dose-dependent NF-kappaB reporter activity in TLR2-expressing human embryo kidney 293 T cells and that Ft LVS-induced murine macrophage proinflammatory cytokine gene and protein expression is TLR2-dependent. We demonstrated further that Ft can signal through TLR2 from within the phagosome and that phagosomal retention of Ft leads to greatly increased expression of a subset of proinflammatory genes. The two adaptor proteins associated with TLR2-mediated signaling are MyD88 and TIRAP. Although MyD88 is absolutely required for the Ft-induced macrophage cytokine response, the requirement for TIRAP can be overcome through retention of Ft within the phagosome. TIRAP-independent signaling was observed whether Ft was retained in the phagosome as a result of bacterial mutation (LVSDeltaiglC) or BFA-mediated inhibition of phagosome acidification. The requirement for TIRAP in TLR2 signaling could also be overcome by increasing the concentrations of synthetic bacterial TLR2 agonists. Taken together, these data suggest that prolonging or enhancing the interaction between TLR2 and its agonist overcomes the "bridging" function ascribed previously to TIRAP.
Authors:
Leah E Cole; Michelle H W Laird; Anna Seekatz; Araceli Santiago; Zhaozhao Jiang; Eileen Barry; Kari Ann Shirey; Katherine A Fitzgerald; Stefanie N Vogel
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2009-11-04
Journal Detail:
Title:  Journal of leukocyte biology     Volume:  87     ISSN:  1938-3673     ISO Abbreviation:  J. Leukoc. Biol.     Publication Date:  2010 Feb 
Date Detail:
Created Date:  2010-02-03     Completed Date:  2010-02-25     Revised Date:  2011-07-22    
Medline Journal Info:
Nlm Unique ID:  8405628     Medline TA:  J Leukoc Biol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  275-81     Citation Subset:  IM    
Affiliation:
Department of Microbiology and Immunology, University of Maryland, Baltimore, Baltimore, MD 21201, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Cell Line
Cytokines / genetics,  immunology
Francisella tularensis / genetics,  immunology*
Gene Expression Regulation / genetics,  immunology
Humans
Inflammation / genetics,  immunology,  microbiology
Macrophages, Peritoneal / immunology*,  microbiology
Membrane Glycoproteins / genetics,  immunology*
Membrane Transport Proteins / genetics,  immunology*
Mice
Mice, Knockout
Mutation
Myelin Proteins / genetics,  immunology*
Myeloid Differentiation Factor 88 / genetics,  immunology
Phagosomes / genetics,  immunology*,  microbiology
Proteolipids / genetics,  immunology*
Receptors, Interleukin-1 / genetics,  immunology*
Signal Transduction / genetics,  immunology*
Toll-Like Receptor 2 / agonists,  genetics,  immunology*
Grant Support
ID/Acronym/Agency:
AI-067497/AI/NIAID NIH HHS; R01 AI018797-29/AI/NIAID NIH HHS; U54 AI-157168/AI/NIAID NIH HHS
Chemical
Reg. No./Substance:
0/Cytokines; 0/MAL protein, T-cell; 0/Membrane Glycoproteins; 0/Membrane Transport Proteins; 0/Myd88 protein, mouse; 0/Myelin Proteins; 0/Myeloid Differentiation Factor 88; 0/Proteolipids; 0/Receptors, Interleukin-1; 0/TIRAP protein, mouse; 0/Tlr2 protein, mouse; 0/Toll-Like Receptor 2
Comments/Corrections

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