scholarly journals Interferon-regulatory-factor 1 controls Toll-like receptor 9-mediated IFN-β production in myeloid dendritic cells

2007 ◽  
Vol 37 (2) ◽  
pp. 315-327 ◽  
Author(s):  
Frank Schmitz ◽  
Antje Heit ◽  
Simone Guggemoos ◽  
Anne Krug ◽  
Jörg Mages ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Interferon Regulatory Factor ◽  
Toll Like Receptor ◽  
Regulatory Factor ◽  
Myeloid Dendritic Cells ◽  
Interferon Regulatory Factor 1

Suppression of Interferon Regulatory Factor 8 Modulates Toll Like Receptor 2 and Toll Like Receptor 7/8 Induced Dendritic Cell Activation

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2573-2573
Author(s):  
Daniela Werth ◽  
Anita Bringmann ◽  
Katharina Brauer ◽  
Karin von Schwarzenberg ◽  
Stefanie Held ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Western Blot ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Cell Activation ◽  
Nuclear Translocation ◽  
Interferon Regulatory Factor ◽  
Toll Like Receptor ◽  
Regulatory Factor ◽  
Dendritic Cell Activation

Abstract Interferon regulatory factor 8 (IRF-8) is a member of the IRF family of transcription factors, which are stimulated through interferon mediated pathways. In mice, IRF-8 seems to play an essential role in the development and maturation of dendritic cells (DCs). However, very limited knowledge is available about the potential role of IRF-8 in the human system. To bridge this gap we analyzed function and activation of human monocyte-derived dendritic cells (mDCs) lacking IRF-8 expression. To knockdown IRF-8 protein levels, we electroporated mDCs with different siRNAs against IRF-8. Additionally, we stimulated the electroporated mDCs with the Toll like receptor (TLR) 2 ligand Pam3Cys or the TLR 7/8 ligand R848. IRF-8 knockdown in mDCs was verified constantly by Western Blot analysis using an anti-IRF-8 antibody. We found that IRF-8 knockdown clearly diminished the expression of the human lymphocyte antigen molecules HLA-ABC and HLA-DR in Pam3Cys and R848 stimulated mDCs. To gain functional data, we performed ELISAs to determine cytokine and chemokine secretion. The electroporation of mDCs with IRF-8 specific siRNA resulted in profound inhibition of secretion of the cytokines IL-6, IL-12 and TNF-a as well as the chemokines MIP-1a (CCL3), MCP-1 (CCL2) and RANTES (CCL5). To get additional information on IRF-8 function in human mDCs, the regulation of signal transduction pathways was determined by Western Blot analysis. The suppression of IRF-8 diminished the nuclear translocation of the NF-kB family member’s c-Rel and RelB as well as PU.1 and IRF-3 in activated mDCs. In addition, we showed that the suppression of IRF-8 caused a reduced phosphorylation of ERK and JNK, but had no effect on the expression of STAT3. In summary, the knockdown of IRF-8 reduced the capability of mDCs to develop appropriate phenotype and functions in response to activating stimuli. Our results indicate that these effects are mediated via the ERK, NF-kB and PU.1 signalling pathways. IRF-8 plays an important role in the activation and function of human mDCs.

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