[The intracellular mechanism of NF-kappa B activation involved in iNOS and chemokine induction in C6 glioma cells].
To elucidate the intracellular mechanism of NF-kappa B activation, we performed the involvement of I kappa B alpha of NF-kappa B in the expression of inducible NO synthase (iNOS) and chemokine (CINC) following pretreatment with bacterial endotoxin (LPS) or IL-1 beta, respectively, using rat C6 glioma cells. We found that herbimycin A, a tyrosine protein kinase inhibitor, blocked: 1) LPS/IFN gamma-induced iNOS expression, 2) LPS-induced intranuclear translocation of activated NF-kappa B (p50. p65) and 3) IFN gamma-induced autophosphorylation and activation of Jak 2 and Stat 1 as well as intranuclear translocation of phosphorylated Stat 1. Furthermore, transfection of a dominant negative form of I kappa B alpha (SS-->AA) suppressed LPS/IFN gamma-induced iNOS expression, suggesting that NF-kappa B, in particular, I kappa B alpha molecules could play important roles in the iNOS expression. We also found in IL-1 beta-induced CINC expression using cultured C6 glioma cells, the transient translocation of NF-kappa B in response to IL-1 beta is partly dependent on transient proteasome activation. Thus we suggest that the formation of heterodimer p50.p65 from inactive trimer p50.p65.I kappa B alpha, particularly, proteolytic degradation and dissociation of I kappa B alpha from p50.p65 are a critical phase in NF-kappa B activation during LPS-induced iNOS and IL-1 beta-induced CINC expression in astroglial cells.
Nomura
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Y
Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan.
Uehara
T
T
Nishiya
T
T
D000818:Animals; D019743:Chemokines, CXC / Q000096:biosynthesis*; D002630:Chemotactic Factors / Q000096:biosynthesis*; D004268:DNA-Binding Proteins / Q000502:physiology; D004731:Endotoxins / Q000494:pharmacology; D005910:Glioma / Q000378:metabolism*; D006133:Growth Substances / Q000096:biosynthesis*; D020672:I-kappa B Proteins; D036341:Intercellular Signaling Peptides and Proteins; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000502:physiology*; D009363:Neoplasm Proteins / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000096:biosynthesis*; D052247:Nitric Oxide Synthase Type II; D051381:Rats; D014178:Translocation, Genetic; D014407:Tumor Cells, Cultured
D019743:Chemokines, CXC; D002630:Chemotactic Factors; D004268:DNA-Binding Proteins; D004731:Endotoxins; D006133:Growth Substances; D020672:I-kappa B Proteins; D036341:Intercellular Signaling Peptides and Proteins; D016328:NF-kappa B; D009363:Neoplasm Proteins; C000606206:Nfkbia protein, rat; D000072000:NF-KappaB Inhibitor alpha; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat