Lipopolysaccharide-induced NF-κB nuclear translocation is primarily dependent on MyD88, but TNF$\alpha$ expression requires TRIF and MyD88


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Authors
Sakai, J 
Cammarota, E 
Wright, JA 
Gottschalk, RA 
Abstract

TLR4 signalling through the MyD88 and TRIF-dependent pathways initiates translocation of the transcription factor NF-κB into the nucleus. In cell population studies using mathematical modeling and functional analyses, Cheng et al. suggested that LPS-driven activation of MyD88, in the absence of TRIF, impairs NF-κB translocation. We tested the model proposed by Cheng et al. using real-time single cell analysis in macrophages expressing EGFP-tagged p65 and a TNFα promoter-driven mCherry. Following LPS stimulation, cells lacking TRIF show a pattern of NF-κB dynamics that is unaltered from wild-type cells, but activation of the TNFα promoter is impaired. In macrophages lacking MyD88, there is minimal NF-κB translocation to the nucleus in response to LPS stimulation, and there is no activation of the TNFα promoter. These findings confirm that signalling through MyD88 is the primary driver for LPS-dependent NF-κB translocation to the nucleus. The pattern of NF-κB dynamics in TRIF-deficient cells does not, however, directly reflect the kinetics of TNFα promoter activation, supporting the concept that TRIF-dependent signalling plays an important role in the transcription of this cytokine.

Description
Keywords
cell signalling, innate immune cells
Journal Title
Scientific Reports
Conference Name
Journal ISSN
2045-2322
2045-2322
Volume Title
7
Publisher
Nature Publishing Group
Sponsorship
Biotechnology and Biological Sciences Research Council (BB/H021930/1)
Biotechnology and Biological Sciences Research Council (BB/K006436/1)
Medical Research Council (G1000133)
Wellcome Trust (108045/Z/15/Z)
J.S. is supported by the Cambridge Commonwealth, European and International Trust. CEB was supported by a BBSRC fellowship (BB/H021930/1) and a Wellcome Trust Investigator award (WT108045AIA). E.C. and P.C. acknowledge EU-ITN Transpol and EU-ERC Hydrosync. I.D.C.F. is supported by the intramural Research Program of the National Institute of Allergy and Infectious Diseases.
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