A semi-synthetic derivative of artemisinin, artesunate inhibits prostaglandin E2 production in LPS/IFNγ-activated BV2 microglia

Artesunate is a semi-synthetic derivative of artemisinin used to treat malaria, and has been shown to possess anti-inflammatory activity. In this study, we have investigated the effect of artesunate on PGE(2) production/COX-2 protein expression in LPS + IFN gamma-activated BV2 microglia. To further understand the mechanism of action of this compound, we investigated its interference with NF-kappa B and p38 MAPK signalling pathways. PGE(2) production was determined using EIA, while protein expressions of inflammatory targets like COX-2, mPGES-1, I kappa B, p38 and MAPKAPK2 were evaluated using western blot. An NF-kappa B-bearing luciferase reporter gene assay was used to test the effect of artesunate on NF-kappa B-mediated pro-inflammatory gene expression in HEK293 cells stimulated with TNF alpha (1 ng/ml). Artesunate (2 and 4 mu M), significantly (p<0.01) suppressed PGE(2) production in LPS + IFN gamma-activated BV2 microglia. This effect was found to be mediated via reduction in COX-2 and mPGES-1 proteins. Artesunate also produced significant inhibition of TNF alpha and IL-6 production in activated BV2 microglia. Further investigations showed that artesunate (0.5-4 mu M) significantly (p<0.001) reduced NF-kappa B-driven luciferase expression, and inhibited I kappa B phosphorylation and degradation, through inhibition of IKK. Artesunate inhibited phosphorylation of p38 MAPK and its substrate MAPKAPK2 following stimulation of microglia with LPS + IFN gamma. Taken together, we have shown that artesunate prevents neuroinflammation in BV2 microglia by interfering with NF-kappa B and p38 MAPK signalling. Crown Copyright (C) 2014 Published by Elsevier Ltd. All rights reserved.