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JAK inhibitors AG-490 and WHI-P154 decrease IFN-gamma-induced iNOS expression and NO production in macrophages
Outi Sareila1, Riku Korhonen, Outi Kärpänniemi
1The Immunopharmacology Research Group, Medical School, University of Tampere and Research Unit, Tampere University Hospital, 33014 Tampere, Finland.
Mediators of Inflammation
|August 3, 2006
Summary
Janus kinase (JAK) inhibitors AG-490 and WHI-P154 reduce inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) production in macrophages. This occurs by inhibiting the JAK-STAT1 pathway, crucial in inflammatory responses.
Area of Science:
- Immunology
- Molecular Biology
- Biochemistry
Background:
- Inducible nitric oxide synthase (iNOS) plays a key role in inflammatory processes by producing nitric oxide (NO).
- The Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway, particularly STAT1alpha, is involved in regulating inflammatory gene expression.
Purpose of the Study:
- To investigate the impact of JAK inhibitors AG-490 and WHI-P154 on iNOS expression and NO production.
- To elucidate the role of the JAK-STAT1 pathway in modulating iNOS and NO levels in response to interferon-gamma (IFN-gamma).
Main Methods:
- J774 murine macrophages were stimulated with IFN-gamma.
- The effects of JAK inhibitors AG-490 and WHI-P154 on nuclear STAT1alpha levels, iNOS protein and mRNA expression, and NO production were assessed.
- mRNA decay was evaluated using the actinomycin D assay.
Main Results:
- AG-490 and WHI-P154 significantly decreased IFN-gamma-induced nuclear STAT1alpha levels.
- Both JAK inhibitors reduced iNOS protein and mRNA expression in a concentration-dependent manner.
- NO production was attenuated by AG-490 and WHI-P154, without affecting iNOS mRNA stability.
Conclusions:
- Inhibition of the JAK-STAT1 pathway by AG-490 or WHI-P154 effectively attenuates iNOS expression and NO production.
- These findings highlight the JAK-STAT1 pathway as a potential therapeutic target for inflammatory conditions involving iNOS and NO.