NF-κB and p38 signalling-dependent inhibition of neuroinflammation by artemether

UP Okorji, O Olajide. University of Huddersfield, Huddersfield, UK

Artemether (sigma), a lipid-soluble derivative of artemisinin, has been shown to possess anti-inflammatory activity in mouse model of colitis [1]. In addition, experiments on experimental rheumatoid arthritis have shown that artemether could be offered as a second-line drug treatment of rheumatoid arthritis [2]. Moreover, a closely related compound artesunate (another derivative of artemisinin) has been shown to inhibit neuroinflammation in LPS/IFN-γ activated BV2 cells [3]. In this study the anti-inflammatory effect of artemether on LPS activated BV2 cells was investigated. BV2 cells were pre-treated with artemether (5 - 40μM) for 30 min and stimulated with LPS for 1 h. Thereafter, cytoplasmic and nuclear extracts were collected. Western blot was used to measure phospho-IκB, phospho-NF-κB, phospho-p38, phospho-MAPKAPK2 and phospho-MKK3/6 protein expressions. Values of all experiments were represented as a mean ± SEM of at least 3 experiments. Pre-treatment with artemether significantly (p<0.05) inhibited IκB and NF-κB protein expression in LPS-activated BV2 cells. At 40μM, pre-treatment with artemether produced 45% phospho-IκB and 48% phospho-NF-κB (Fig.1A) protein expression (p<0.001) when compared to the LPS control. In addition, artemether attenuated p38 MAPK signalling by inhibiting phospho-p38 and its upstream kinases MAPKAPK2 and MKK3/6. At 40μM, pre-treatment with artemether resulted in the production of 32% phospho-p38 (p<0.001) when compared to the LPS control (Fig.1B). More so, 40% and 37% phospho-MAPKAPK2 and MKK3/6 (p<0.001) were produced at this concentration when compared to the LPS control. These data show that artemether inhibits inflammation in LPS-activated BV-2 cells through interference with NF-κB and p38 signalling pathways.

A. B.

Figure 1: Effect of Artemether (5-40µM) on NF-κB and p38MAPK protein expressions in LPS-activated BV-2 microglia cells. A. Artemether (5-40µM) inhibits the expression of p-NF-κB protein expression in LPS-activated BV-2 microglia cells. B. Artemether (5-40µM) inhibits protein expression of p-p38MAPK in LPS-activated BV-2 microglia cells.

References

(1) Lee YJ, Choi DY, Choi IS, et al. (2011) J Neuroinflammation 8: 132 – 1316.

(2) Cuzzocrea S, Saadat F, Di Paola R, Mirshafiey A (2005) Immunopharmacology and Immunotoxiciology. 27, 4 (2005) 615 – 630

(3) Okorji UP, Olajide OA (2014) Bioorganic and Medicinal Chemistry. 22(17) 4726-4734