title: Phosphoinositide 3-kinaseγ controls the intracellular localization of CpG to limit DNA-PKcs-dependent IL-10 production in macrophages.
abstract: Synthetic oligodeoxynucleotides containing unmethylated CpG motifs (CpG) stimulate innate immune responses. Phosphoinositide 3-kinase (PI3K) has been implicated in CpG-induced immune activation; however, its precise role has not yet been clarified. CpG-induced production of IL-10 was dramatically increased in macrophages deficient in PI3Kγ (p110γ(-/-)). By contrast, LPS-induced production of IL-10 was unchanged in the cells. CpG-induced, but not LPS-induced, IL-10 production was almost completely abolished in SCID mice having mutations in DNA-dependent protein kinase catalytic subunit (DNA-PKcs). Furthermore, wortmannin, an inhibitor of DNA-PKcs, completely inhibited CpG-induced IL-10 production, both in wild type and p110γ(-/-) cells. Microscopic analyses revealed that CpG preferentially localized with DNA-PKcs in p110γ(-/-) cells than in wild type cells. In addition, CpG was preferentially co-localized with the acidic lysosomal marker, LysoTracker, in p110γ(-/-) cells, and with an early endosome marker, EEA1, in wild type cells. Over-expression of p110γ in Cos7 cells resulted in decreased acidification of CpG containing endosome. A similar effect was reproduced using kinase-dead mutants, but not with a ras-binding site mutant, of p110γ. Thus, it is likely that p110γ, in a manner independent of its kinase activity, inhibits the acidification of CpG-containing endosomes. It is considered that increased acidification of CpG-containing endosomes in p110γ(-/-) cells enforces endosomal escape of CpG, which results in increased association of CpG with DNA-PKcs to up-regulate IL-10 production in macrophages.
authors: Division of Molecular Medical Science, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan. khazeki@hiroshima-u.ac.jp
authors: Kaoru
authors: K
authors: Hazeki
authors: Yukiko
authors: Y
authors: Kametani
authors: Hiroki
authors: H
authors: Murakami
authors: Masami
authors: M
authors: Uehara
authors: Yuki
authors: Y
authors: Ishikawa
authors: Kiyomi
authors: K
authors: Nigorikawa
authors: Shunsuke
authors: S
authors: Takasuga
authors: Takehiko
authors: T
authors: Sasaki
authors: Tsukasa
authors: T
authors: Seya
authors: Misako
authors: M
authors: Matsumoto
authors: Osamu
authors: O
authors: Hazeki
mesh_terms: D000143:Acids / Q000378:metabolism; D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D002412:Cations; D058544:Class Ib Phosphatidylinositol 3-Kinase / Q000172:deficiency / Q000378:metabolism*; D051747:DNA-Activated Protein Kinase / Q000378:metabolism*; D011992:Endosomes / Q000187:drug effects / Q000378:metabolism; D005260:Female; D016753:Interleukin-10 / Q000096:biosynthesis*; D042541:Intracellular Space / Q000187:drug effects / Q000201:enzymology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008081:Liposomes / Q000378:metabolism; D008264:Macrophages / Q000187:drug effects / Q000201:enzymology*; D051379:Mice; D008810:Mice, Inbred C57BL; D016513:Mice, SCID; D009838:Oligodeoxyribonucleotides / Q000378:metabolism*; D021381:Protein Transport / Q000187:drug effects; D000077191:Wortmannin
chemical_list: D000143:Acids; D000730:Androstadienes; C408982:CPG-oligonucleotide; D002412:Cations; D008070:Lipopolysaccharides; D008081:Liposomes; D009838:Oligodeoxyribonucleotides; D016753:Interleukin-10; D058544:Class Ib Phosphatidylinositol 3-Kinase; C546764:Pik3cg protein, mouse; D051747:DNA-Activated Protein Kinase; D000077191:Wortmannin