Bikunin inhibits lipopolysaccharide-induced tumor necrosis factor alpha induction in macrophages.
Bikunin, a Kunitz-type protease inhibitor, exhibits anti-inflammatory activity in protection against cancer and inflammation. To investigate the molecular mechanism of this inhibition, we analyzed the effect of bikunin on tumor necrosis factor alpha (TNF-alpha) production in human peripheral mononuclear cells stimulated by lipopolysaccharide (LPS), an inflammatory inducer. Here, we show the following results. (i) LPS induced TNF-alpha expression in time- and dose-dependent manners through phosphorylation of extracellular signal-regulated kinases 1 and 2 (ERK1/2), c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase pathways. (ii) Bikunin inhibits LPS-induced up-regulation of TNF-alpha protein expression in a dose-dependent manner, reaching 60% inhibition at the highest doses of bikunin tested (5.0 microM). (iii) Inhibition by bikunin of TNF-alpha induction correlates with the suppressive capacity of ERK1/2, JNK, and p38 signaling pathways, implicating repressions of at least three different signals in the inhibition. (iv) Bikunin blocks the induction of TNF-alpha target molecules interleukin-1beta (IL-1beta) and IL-6 proteins. (v) Bikunin is functional in vivo, and this glycoprotein blocks systemic TNF-alpha release in mice challenged with LPS. (vi) Finally, bikunin can prevent LPS-induced lethality. In conclusion, bikunin significantly inhibits LPS-induced TNF-alpha production, suggesting a mechanism of anti-inflammation by bikunin through control of cytokine induction during inflammation. Bikunin might be a candidate for the treatment of inflammation, including septic shock.
Matsuzaki
Hidenori
H
NetForce Co. Ltd., Taiko, Japan.
Kobayashi
Hiroshi
H
Yagyu
Tatsuo
T
Wakahara
Kiyoshi
K
Kondo
Toshiharu
T
Kurita
Noriyuki
N
Sekino
Hideo
H
Inagaki
Kiyokazu
K
Suzuki
Mika
M
Kanayama
Naohiro
N
Terao
Toshihiko
T
D000818:Animals; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008070:Lipopolysaccharides / Q000008:administration & dosage*; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D008262:Macrophage Activation / Q000187:drug effects; D008264:Macrophages / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000008:administration & dosage*; D051379:Mice; D015842:Serine Proteinase Inhibitors / Q000008:administration & dosage*; D014360:Trypsin Inhibitor, Kunitz Soybean / Q000008:administration & dosage*; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*
D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; C109148:SPINT2 protein, human; D015842:Serine Proteinase Inhibitors; D014409:Tumor Necrosis Factor-alpha; D014360:Trypsin Inhibitor, Kunitz Soybean