PI3K p110beta positively regulates lipopolysaccharide-induced IL-12 production in human macrophages and dendritic cells and JNK1 plays a novel role.
The PI3K family is thought to participate in TLR signaling, and it has been reported to be a negative regulator of TLR-mediated production of IL-12, a key inducer of Th1 responses. However, the role of individual PI3K subtypes in IL-12 production remains obscure. We defined the distinct regulation of LPS-mediated IL-12 production by p110alpha and p110beta catalytic subunits of PI3K in human APCs. We observed that knockdown of PI3K p110beta by small interfering RNA (siRNA) suppressed both LPS-induced IL-12 protein production and mRNA expression in monocyte-derived macrophages and dendritic cells (DCs). Knockdown of PI3K p110alpha by siRNA reduced LPS-induced IL-12 protein production in both cell types. Conversely, knockdown of PI3K p110alpha suppressed LPS-induced IL-12 mRNA expression in monocyte-derived macrophages but minimally affected monocyte-derived DCs. PI3K p110beta siRNA inhibited JNK activation, but not p38 MAPK or ERK activation, stimulated by LPS, while PI3K p110alpha siRNA did not affect LPS-induced JNK, p38 MAPK, or ERK activation in both cell types. Transfection of siRNA against JNK1, JNK2, and both decreased LPS-induced IL-12 production. Furthermore, PI3K p110beta siRNA attenuated LPS-induced JNK1 phosphorylation, while not affecting JNK2 phosphorylation. Our findings indicate that PI3K p110beta positively controls LPS-induced IL-12 production through the JNK1-dependent pathway in human macrophages and DCs.
Utsugi
Mitsuyoshi
M
Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Maebashi, Japan. mutsugi@med.gunma-u.ac.jp
Dobashi
Kunio
K
Ono
Akihiro
A
Ishizuka
Tamotsu
T
Matsuzaki
Shin-ichi
S
Hisada
Takeshi
T
Shimizu
Yasuo
Y
Kawata
Tadayoshi
T
Aoki
Haruka
H
Kamide
Yosuke
Y
Mori
Masatomo
M
D000328:Adult; D002478:Cells, Cultured; D058534:Class I Phosphatidylinositol 3-Kinases; D003713:Dendritic Cells / Q000201:enzymology / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D018664:Interleukin-12 / Q000096:biosynthesis*; D053762:Interleukin-12 Subunit p40 / Q000096:biosynthesis*; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D020935:MAP Kinase Signaling System / Q000276:immunology; D008264:Macrophages / Q000201:enzymology / Q000276:immunology* / Q000378:metabolism; D048055:Mitogen-Activated Protein Kinase 8 / Q000037:antagonists & inhibitors / Q000502:physiology*; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000502:physiology*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D034622:RNA Interference; D015854:Up-Regulation / Q000235:genetics / Q000276:immunology*
D058534:Class I Phosphatidylinositol 3-Kinases; D018664:Interleukin-12; D053762:Interleukin-12 Subunit p40; D007527:Isoenzymes; D008070:Lipopolysaccharides; D048055:Mitogen-Activated Protein Kinase 8; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; C497132:PIK3CB protein, human