Organ-specific role of MyD88 for gene regulation during polymicrobial peritonitis.
Sepsis leads to the rapid induction of proinflammatory signaling cascades by activation of the innate immune system through Toll-like receptors (TLR). To characterize the role of TLR signaling through MyD88 for sepsis-induced transcriptional activation, we investigated gene expression during polymicrobial septic peritonitis by microarray analysis. Comparison of gene expression profiles for spleens and livers from septic wild-type and MyD88-deficient mice revealed striking organ-specific differences. Whereas MyD88 deficiency strongly reduced sepsis-induced gene expression in the liver, gene expression in the spleen was largely independent of MyD88, indicating organ-specific transcriptional regulation during polymicrobial sepsis. In addition to genes regulated by MyD88 in an organ-dependent manner, we also identified genes that exhibited an organ-independent influence of MyD88 and mostly encoded cytokines and chemokines. Notably, the expression of interferon (IFN)-regulated genes was markedly increased in septic MyD88-deficient mice compared to that in septic wild-type controls. Expression of IFN-regulated genes was dependent on the adapter protein TRIF. These results suggest that the influence of MyD88 on gene expression during sepsis strongly depends on the organ compartment affected by inflammation and that the lack of MyD88 may lead to disbalance of the expression of IFN-regulated genes.
Weighardt
Heike
H
Department of Surgery, Technische Universität München, Ismaningerstrasse 22, 81675 Munich, Germany. weighardt@nt1.chir.med.tu-muenchen.de
Mages
Jörg
J
Jusek
Gabriela
G
Kaiser-Moore
Simone
S
Lang
Roland
R
Holzmann
Bernhard
B
D048868:Adaptor Proteins, Signal Transducing / Q000502:physiology*; D033942:Adaptor Proteins, Vesicular Transport / Q000502:physiology; D000818:Animals; D016470:Bacteremia / Q000276:immunology*; D018925:Chemokines / Q000235:genetics; D016207:Cytokines / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D007372:Interferons / Q000494:pharmacology; D008099:Liver / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D053594:Myeloid Differentiation Factor 88; D009928:Organ Specificity; D010538:Peritonitis / Q000276:immunology*; D013154:Spleen / Q000378:metabolism*; D051193:Toll-Like Receptors / Q000502:physiology
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D018925:Chemokines; D016207:Cytokines; D007372:Interferons; D053594:Myeloid Differentiation Factor 88; D051193:Toll-Like Receptors; C507780:Myd88 protein, mouse; C476286:Ticam1 protein, mouse