[Frontiers in Bioscience E3, 1079-1091, June 1, 2011]

Costunolide inhibits proinflammatory cytokines and iNOS in activated murine BV2 microglia

Nirmala Arul Rayan2, Nimmi Baby1, Daisy Pitchai2, Fransisca Indraswari1 Eng-Ang Ling1 Jia Lu3,Thameem Dheen1

1Department of Anatomy, The Yong Loo Lin School of Medicine, National University of Singapore, Singapore-117517., 2Department of Biotechnology, Holy Cross College, Tiruchirapalli, India, 3Defense Medical and Environmental Research Institute, DSO National Laboratories, Singapore 117510

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. Materials and methods
3.1. Murine BV-2 cell culture
3.2. Treatment of BV2 cells
3.3. Cytotoxicity assay
3.4. Immunofluorescence labeling
3.5. RNA isolation and real-time RT-PCR
3.6. Nitrite assay
3.7. NFκB transcription factor assay
3.8. Western immunoblot assay
3.9. Statistical analysis
4. Results
4.1. Effect of costunolide on BV2 microglial cell viability
4.2. Inhibitory effects of costunolide on LPS-induced TNF-alpha, IL-1, IL-6 mRNA expression in BV2 cells
4.3. Effect of costunolide on the expression of iNOS and NO release in LPS-stimulated BV2 microglia
4.4. Attenuating role of Costunolide on Cox gene expression and NF-kappaB translocation from cytoplasm to nucleus in microglia exposed to LPS
4.5. Costunolide mediated inhibition of MCP-1 through induction of MKP-1 in activated BV2 microglia
5. Discussion
6. Conclusion
7. Acknowldgement
8. References

1. ABSTRACT

Costunolide, a sesquiterpene lactone present in Costus speciosus root exerts a variety of pharmacological activity but its effects on neuroinflammation have not been studied. Microglia, the resident phagocytic cells in the central nervous system respond to neuroinflammation and their overwhelming response in turn aggravate brain damage during infection, ischemia and neurodegenerative diseases. In this study, we report the effect of Costunolide on the production of proinflammatory mediators and mechanisms involved in BV2 microglial cells stimulated with LPS. Costunolide attenuated the expression of tumour necrosis factor-alpha, interleukin-1,6, inducible nitric oxide synthase, monocyte chemotactic protein 1 and cyclooxygenase 2 in activated microglia. This Costunolide-mediated inhibition was correspondent with the inhibition of NFkappaB activation. It has been further shown that Costunolide suppressed MAPK pathway activation by inducing MKP-1 production. Collectively our results suggest that Costunolide shows an ability to inhibit expression of multiple neuroinflammatory mediators and this is attributable to the compounds inhibition of NFkappaB and MAPK activation. This novel role of Costunolide upon investigation may aid in developing better therapeutic strategies for treatment of neuroinflammatory diseases.