Suppression of lipopolysaccharide-induced cytokine production of gingival fibroblasts by a soybean, Kunitz trypsin inhibitor.
BACKGROUND
Human bikunin, a Kunitz-type trypsin inhibitor, inhibits inflammation by down-regulating the expression of proinflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha) in tumor cells and inflammatory cells.


OBJECTIVE
We analyzed the effect of a soybean-derived Kunitz trypsin inhibitor (KTI) on TNF-alpha production in human gingival fibroblasts stimulated by lipopolysaccharide (LPS), an inflammatory inducer.


METHODS
Mitogen-activated protein kinase (MAPK) activation and cytokine levels were monitored using western blot and a specific enzyme-linked immunosorbent assay (ELISA).


RESULTS
Here, we show (i) a soybean KTI abrogates LPS-induced up-regulation of TNF-alpha mRNA and protein expression in a dose-dependent manner in gingival fibroblasts, (ii) KTI also blocks the induction of TNF-alpha target molecules interleukin-1beta (IL-1beta) and IL-6 proteins, (iii) inhibition by KTI of TNF-alpha induction correlates with the suppressive capacity of extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 signaling pathways, implicating repressed ERK1/2 and p38 signalings in the inhibition, and (iv) pretreatment of cells with KTI blocked LPS-induced nuclear factor kappaB (NFkappaB) activation.


CONCLUSIONS
Our results indicate that KTI inhibits LPS-induced up-regulation of cytokine expression possibly through suppression of ERK1/2 and p38 kinase-mediated NFkappaB activation. These findings may identify anti-inflammatory properties of KTI at the level of gingival fibroblasts and may be relevant to the use of KTI in modulating inflammation, including periodontal disease.
Kobayashi
Hiroshi
H
Department of Obstetrics and Gynecology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan. hirokoba@hama-med.ac.jp
Yoshida
Ryuji
R
Kanada
Yasufumi
Y
Fukuda
Yoichi
Y
Yagyu
Tatsuo
T
Inagaki
Kiyokazu
K
Kondo
Toshiharu
T
Kurita
Noriyuki
N
Suzuki
Mika
M
Kanayama
Naohiro
N
Terao
Toshihiko
T
D000328:Adult; D002478:Cells, Cultured; D015536:Down-Regulation; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D005347:Fibroblasts / Q000187:drug effects*; D005881:Gingiva / Q000166:cytology / Q000187:drug effects*; D006801:Humans; D018836:Inflammation Mediators / Q000494:pharmacology*; D007375:Interleukin-1 / Q000037:antagonists & inhibitors; D008070:Lipopolysaccharides / Q000494:pharmacology*; D020935:MAP Kinase Signaling System / Q000187:drug effects; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors; D020928:Mitogen-Activated Protein Kinases / Q000187:drug effects; D016328:NF-kappa B / Q000037:antagonists & inhibitors; D014360:Trypsin Inhibitor, Kunitz Soybean / Q000494:pharmacology*; D014361:Trypsin Inhibitors / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors*; D015854:Up-Regulation / Q000187:drug effects; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors; D000093242:Interleukin-6 Inhibitors
D004791:Enzyme Inhibitors; D018836:Inflammation Mediators; D007375:Interleukin-1; D008070:Lipopolysaccharides; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D016328:NF-kappa B; D014360:Trypsin Inhibitor, Kunitz Soybean; D014361:Trypsin Inhibitors; D014409:Tumor Necrosis Factor-alpha; D048051:p38 Mitogen-Activated Protein Kinases; D000093242:Interleukin-6 Inhibitors