Protein Kinase C-alpha Regulates Toll-like Receptor 4-Mediated Inducible Nitric Oxide Synthase Expression.
- Author:
Jin Gu LEE
1
;
Byung Rho CHIN
;
Suk Hwan BAEK
Author Information
1. Aging-associated Vascular Disease Research Center, Department of Biochemistry & Molecular Biology, College of Medicine, Yeungnam University, Korea. sbaek@med.yu.ac.kr
- Publication Type:Original Article
- Keywords:
lipopolysaccharide;
Inducible nitric oxide synthase;
protein kinase C;
NF-kappaB
- MeSH:
Bacterial Infections;
Blotting, Western;
Cell Line;
I-kappa B Proteins;
Immunity, Innate;
Isoenzymes;
Luciferases;
Macrophages;
NF-kappa B;
Nitric Oxide;
Nitric Oxide Synthase Type II;
Protein Kinase C;
Protein Kinase C-alpha;
Protein Kinases;
Toll-Like Receptors;
Transcriptional Activation
- From:Journal of the Korean Association of Oral and Maxillofacial Surgeons
2008;34(1):28-35
- CountryRepublic of Korea
- Language:English
-
Abstract:
PURPOSE: The nitric oxide (NO) release by inducible nitric oxide synthase (iNOS) is the key events in macrophage response to lipopolysaccharide (LPS) which is suggested to be a crucial mediator for inflammatory and innate immune responses. NO is an important mediator involved in many host defense action and may also lead to a harmful host response to bacterial infection. However, given the importance of iNOS in a variety of pathophysiological conditions, control of its expression and signaling events in response to LPS has been the subject of considerable investigation. MATERIALS AND METHODS: The Raw264.7 macrophage cell line was used to observe LPS-stimulated iNOS expression. The expression of iNOS is observed by Western blot analysis and real-time RT-PCR. Protein kinase C (PKC)-alpha overexpressing Raw264.7 cells are established to determine the involvement of PKC-alpha in LPS-mediated iNOS expression. NF-kappaB activity is measured by IkappaBalpha degradation and NF-kappaB luciferase activity assay. RESULTS: We found that various PKC isozymes regulate LPS-induced iNOS expression at the transcriptional and translational levels. The involvement of PKC-alpha in LPS-mediated iNOS induction was further confirmed by increased iNOS expression in PKC-alpha overexpressing cells. NF-kappaB dependent transactivation by LPS was observed and PKC-alpha specific inhibitory peptide abolished this activation, indicating that NF-kappaB activation is dependent on PKC-alpha. CONCLUSION: Our data suggests that PKC-alpha is involved in LPS-mediated iNOS expression and that its downstream target is NF-kappaB. Although PKC-alpha is a crucial mediator in the iNOS regulation, other PKC isozymes may contribute LPS-stimulated iNOS expression. This finding is needed to be elucidated in further study.
