Abstract
Interferon-γ (IFN-γ) plays a crucial role in innate immunity and inflammation. It causes the synergistic effect on endotoxin lipopolysaccharide (LPS)-stimulated inducible nitric oxide synthase (iNOS)/NO biosynthesis; however, the mechanism remains unclear. In the present study, we investigated the effects of glycogen synthase kinase-3 (GSK-3)-mediated inhibition of anti-inflammatory interleukin-10 (IL-10). We found, in LPS-stimulated macrophages, that IFN-γ increased iNOS expression and NO production in a time-dependent manner. In addition, ELISA analysis showed the upregulation of tumor necrosis factor-α and regulated on activation, normal T expressed and secreted, and the downregulation of IL-10. RT-PCR further showed changes in the IL-10 mRNA level as well. Treating cells with recombinant IL-10 showed a decrease in IFN-γ/LPS-induced iNOS/NO biosynthesis, whereas anti-IL-10 neutralizing antibodies enhanced this effect, suggesting that IL-10 acts in an anti-inflammatory role. GSK-3-inhibitor treatment blocked IFN-γ/LPS-induced iNOS/NO biosynthesis but upregulated IL-10 production. Inhibiting GSK-3 using short-interference RNA showed similar results. Additionally, treating cells with anti-IL-10 neutralizing antibodies blocked these effects. We further showed that inhibiting GSK-3 increased phosphorylation of transcription factor cyclic AMP response element binding protein. Inhibiting protein tyrosine kinase Pyk2, an upstream regulator of GSK-3β, caused inhibition on IFN-γ/LPS-induced GSK-3β phosphorylation at tyrosine 216 and iNOS/NO biosynthesis. Taken together, these findings reveal the involvement of GSK-3-inhibited IL-10 on the induction of iNOS/NO biosynthesis by IFN-γ synergized with LPS.
Original language | English |
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Pages (from-to) | 746-755 |
Number of pages | 10 |
Journal | Journal of Cellular Biochemistry |
Volume | 105 |
Issue number | 3 |
DOIs | |
Publication status | Published - Oct 15 2008 |
Externally published | Yes |
Keywords
- GSK-3
- IFN-γ
- IL-10
- iNOS
- LPS
- Macrophage
- NO
ASJC Scopus subject areas
- Biochemistry
- Cell Biology
- Molecular Biology