Calprotectin release from human neutrophils is induced by Porphyromonas gingivalis lipopolysaccharide via the CD-14-Toll-like receptor-nuclear factor kappaB pathway.
OBJECTIVE
Calprotectin is a cytosolic protein with antibacterial action in leukocytes and its level increases in some inflammatory diseases, including periodontal diseases, rheumatoid arthritis and ulcerative colitis. Recently, we found that the lipopolysaccharide of Porphyromonas gingivalis (P-LPS) induced calprotectin release from human neutrophils. P-LPS, a major virulence factor of periodontal pathogens, is known to induce the production and release of inflammatory cytokines through CD14, Toll-like receptor (TLR) and nuclear factor kappaB (NF-kappaB). In the present study, we investigated whether calprotectin release by P-LPS is induced via the CD14-TLR-NF-kappaB pathway and the cellular mechanism of calprotectin release in human neutrophils.


METHODS
Human neutrophils were isolated from the peripheral blood of healthy donors and pre-incubated in medium containing antibodies against CD14, TLR2 and TLR4, or several inhibitors of NF-kappaB, microtubules and microfilaments, and then incubated with P-LPS. The calprotectin amount in the culture medium was determined using ELISA, and the nuclear extracts from cells were used for the examination of NF-kappaB binding activity using electrophoretic mobility shift assays.


RESULTS
P-LPS increased calprotectin release from neutrophils and its induction was inhibited by anti-CD14 and anti-TLR2 antibodies, but not by two anti-TLR4 antibodies. NF-kappaB inhibitors suppressed P-LPS-induced NF-kappaB binding activity and calprotectin release. The inhibitors of microtubule and microfilament polymerization significantly decreased P-LPS-induced calprotectin release.


CONCLUSIONS
These results suggest that calprotectin release is induced by P-LPS via the CD14-TLR2-NF-kappaB signal pathway in human neutrophils and may be dependent on microtubule and microfilament systems.
Kido
Jun-ichi
J
Department of Periodontology and Endodontology, Tokushima University School of Dentistry, Kuramoto, Tokushima, Japan. kido@dent.tokushima-u.ac.jp
Kido
Reiko
R
Suryono
Kataoka
Masatoshi
M
Fagerhol
Magne K
MK
Nagata
Toshihiko
T
D008841:Actin Cytoskeleton / Q000187:drug effects; D000199:Actins / Q000037:antagonists & inhibitors; D000328:Adult; D000911:Antibodies, Monoclonal / Q000276:immunology; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D039841:Leukocyte L1 Antigen Complex / Q000187:drug effects / Q000378:metabolism*; D018950:Lipopolysaccharide Receptors / Q000276:immunology / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008297:Male; D008562:Membrane Glycoproteins / Q000276:immunology / Q000378:metabolism*; D008870:Microtubules / Q000187:drug effects; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism*; D016966:Porphyromonas gingivalis / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000276:immunology / Q000378:metabolism*; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors; D050257:Tubulin Modulators
D000199:Actins; D000911:Antibodies, Monoclonal; D007074:Immunoglobulin G; D039841:Leukocyte L1 Antigen Complex; D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D016328:NF-kappa B; D011956:Receptors, Cell Surface; C495342:TLR2 protein, human; C495345:TLR4 protein, human; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors; D050257:Tubulin Modulators