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HO-1 and JAK-2/STAT-1 signals are involved in preferential inhibition of iNOS over COX-2 gene expression by newly synthesized tetrahydroisoquinoline alkaloid, CKD712, in cells activated with lipopolysacchride
- Source :
- Cellular signalling. 20(10)
- Publication Year :
- 2008
-
Abstract
- We found that CKD712, an S enantiomer of YS49, strongly inhibited inducible nitric oxide synthase (iNOS) and NO induction but showed a weak inhibitory effect on cyclooxygenase-2 (COX-2) and PGE(2) induction in LPS-stimulated RAW 264.7 cells. We, therefore, investigated the molecular mechanism(s) responsible for this by using CKD712 in LPS-activated RAW264.7 cells. Treatment with either SP600125, a specific JNK inhibitor or TPCK, a NF-kappaB inhibitor, but neither ERK inhibitor PD98059 nor p38 inhibitor SB203580, significantly inhibited LPS-mediated iNOS and COX-2 induction. CKD712 inhibited NF-kappaB (p65) activity and translocation but failed to prevent JNK activation. However, AG490, a specific JAK-2/STAT-1 inhibitor, efficiently prevented LPS-mediated iNOS induction but not the induction of COX-2, and CKD712 completely blocked STAT-1 phosphorylation by LPS, suggesting that the NF-kappaB and JAK-2/STAT-1 pathways but not the JNK pathway are important for CKD712 action. Interestingly, CKD712 induced heme oxygenase 1 (HO-1) gene expression in LPS-treated cells. LPS-induced NF-kappaB and STAT-1 activation was partially prevented by HO-1 overexpression. Furthermore, HO-1 siRNA partly reversed not only the LPS-induced NF-kappaB activation and STAT-1 phosphorylation but also inhibition of these actions by CKD 712. Additionally, silencing HO-1 by siRNA prevented CKD712 from inhibiting iNOS expression but not COX-2. When examined plasma NO and PGE(2) levels and iNOS and COX-2 protein levels in lung tissues of mice injected with LPS (10 mg/kg), pretreatment with CKD712 greatly prevented NO and iNOS induction in a dose-dependent manner and slightly affected PGE(2) and COX-2 production as expected. Taken together, we conclude that inhibition of JAK-2/STAT-1 pathways by CKD 712 is critical for the differential inhibition of iNOS and COX-2 by LPS in vitro and in vivo where HO-1 induction also contributes to this by partially modulating JAK-2/STAT-1 pathways.
- Subjects :
- MAPK/ERK pathway
Lipopolysaccharides
Cell Survival
p38 mitogen-activated protein kinases
Nitric Oxide Synthase Type II
Nitric Oxide
Models, Biological
Dinoprostone
Gene Expression Regulation, Enzymologic
Cell Line
Mice
Alkaloids
Tetrahydroisoquinolines
Gene silencing
Animals
Gene Silencing
Phosphorylation
Regulation of gene expression
biology
Chemistry
Macrophages
NF-kappa B
Cell Biology
Janus Kinase 2
Macrophage Activation
Molecular biology
Nitric oxide synthase
Heme oxygenase
Enzyme Activation
STAT1 Transcription Factor
Cell culture
Cyclooxygenase 2
biology.protein
lipids (amino acids, peptides, and proteins)
Mitogen-Activated Protein Kinases
Heme Oxygenase-1
Signal Transduction
Subjects
Details
- ISSN :
- 08986568
- Volume :
- 20
- Issue :
- 10
- Database :
- OpenAIRE
- Journal :
- Cellular signalling
- Accession number :
- edsair.doi.dedup.....cb58de79867f3cb15c1f0e429316e931