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Pivotal advance: The pattern recognition receptor ligands lipopolysaccharide and polyinosine-polycytidylic acid stimulate factor B synthesis by the macrophage through distinct but overlapping mechanisms.
- Source :
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Journal of leukocyte biology [J Leukoc Biol] 2010 Oct; Vol. 88 (4), pp. 609-18. Date of Electronic Publication: 2010 Apr 22. - Publication Year :
- 2010
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Abstract
- TLRs and complement are critical to the host response in sepsis, trauma, and ischemia/reperfusion. We hypothesize that TLR stimulation leads to synthesis and release of complement components by macrophages, an important source of extrahepatic complement. RAW264.7 macrophages or peritoneal macrophages from WT and TLR4-, TLR3-, TRIF-, or MyD88-deficient mice were cultured under standard conditions. In some experiments, cells were pretreated with inhibitors of MAPKs or a NF-κB inhibitor. Cells were stimulated with TLR ligands at known stimulatory concentrations. Intratracheal and i.p. injections were also performed in mice. RT-PCR, Western blotting, and immunocytochemistry were used for analysis. Using a RT-PCR-based panel, we demonstrate that of 18 complement components tested, factor B of the alternative pathway is the most robustly up-regulated complement component in macrophages in response to LPS. This up-regulation results in release of factor B into the media. Up-regulation of factor B by LPS is dependent on TLR4, TRIF, JNK, and NF-κB. A screen of other TLR ligands demonstrated that stimulation with poly I:C (dsRNA analog) also results in up-regulation of factor B, which is dependent on JNK and NF-κB but independent of TLR3 and TRIF. Up-regulation of factor B is also observed after intratracheal and i.p. injection of LPS or poly I:C in vivo. PRR stimulation profoundly influences production and release of factor B by macrophages. Understanding the mechanisms of PRR-mediated complement production may lead to strategies aimed at preventing tissue damage in diverse settings, including sepsis, trauma, and ischemia/reperfusion.
- Subjects :
- Animals
Blotting, Western
Complement Factor B immunology
Enzyme-Linked Immunosorbent Assay
Immunohistochemistry
Interferon Inducers immunology
Ligands
Macrophages metabolism
Male
Mice
Mice, Inbred C57BL
Mice, Knockout
Reverse Transcriptase Polymerase Chain Reaction
Toll-Like Receptors metabolism
Complement Factor B biosynthesis
Lipopolysaccharides immunology
Macrophages immunology
Poly I-C immunology
Signal Transduction immunology
Toll-Like Receptors immunology
Subjects
Details
- Language :
- English
- ISSN :
- 1938-3673
- Volume :
- 88
- Issue :
- 4
- Database :
- MEDLINE
- Journal :
- Journal of leukocyte biology
- Publication Type :
- Academic Journal
- Accession number :
- 20413727
- Full Text :
- https://doi.org/10.1189/jlb.0809588