Tropical Journal of Pharmaceutical Research

Original Research Article | OPEN ACCESS

Methanol Extract of Myelophycus caespitosus Inhibits the Inflammatory Response in Lipopolysaccharide-stimulated BV2 Microglial Cells by Downregulating NF-kB via Inhibition of the Akt Signaling Pathway

Rajapaksha Gendara Prasad Tharanga Jayasooriya¹, Chang-Hee Kang¹, Yeon-Jeong Jang¹, Sang-Hyuck Kang¹, Matharage Gayani Dilshara¹, Yung Hyun Choi², Dong-Oh Moon³, Gi-Young Kim¹

¹Laboratory of Immunobiology, Department of Marine Life Sciences, Jeju National University, Jeju 690-756; ²Department of Biochemistry, College of Oriental Medicine, Dongeui University, Busan 614-054; ³Department of Biology Education, College of Education, Gyeongsan, Gyeongbuk 712-714, Republic of Korea.

For correspondence:- Gi-Young Kim Email: immunkim@jejunu.ac.kr Tel:+82647543427

Received: 26 March 2012 Accepted: 8 October 2012 Published: 13 December 2012

Citation: Prasad Tharanga Jayasooriya RG, Kang C, Jang Y, Kang S, Dilshara MG, Choi YH, et al. Methanol Extract of Myelophycus caespitosus Inhibits the Inflammatory Response in Lipopolysaccharide-stimulated BV2 Microglial Cells by Downregulating NF-kB via Inhibition of the Akt Signaling Pathway. Trop J Pharm Res 2012; 11(6):917-924 doi: 10.4314/tjpr.v11i6.7

© 2012 The authors.
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Abstract

Purpose: To determine whether the methanol extract of Myelophycus caespitosus (MEMC) downregulates the expression of pro-inflammatory mediators in lipopolysaccharide (LPS)-stimulated BV2 microglial cells.

Methods: Reverse transcription-polymerase chain reaction (RT-PCR) together with Western blot analysis was used to evaluate the expression of pro-inflammatory mediators such as nitric oxide (NO) and prostaglandin E₂(PGE₂) as well as their regulatory genes such as inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2), in LPS-stimulated BV2 microglial cells. The level of NO production was analyzed using Griess reaction. The release of PGE₂ was determined using sandwich enzyme-linked immunosorbent assay. The DNA-binding activity of nuclear factor-κB (NF-κB) was measured by electrophoretic mobility shift assay.

Results: MEMC inhibited LPS-induced pro-inflammatory mediators, NO and PGE₂, as well as their respective genes, iNOS and COX-2, at both protein and mRNA levels, without any significant cytotoxicity. Treatment with MEMC also substantially reduced the LPS-induced DNA-binding activity of NF-κB and nuclear translocation of NF-κB subunits p65 and p50 via the inhibition of IκBα phosphorylation and degradation. MEMC promoted dephosphorylation of Akt that subsequently suppressed the DNA-binding activity of NF-κB in LPS-stimulated BV2 microglial cells.

Conclusion: Collectively, these data suggest that MEMC attenuates expression of pro-inflammatory mediators such as NO and PGE₂ by suppression of their regulatory genes through the inhibition of Akt-mediated NF-κB activity.

Keywords: Myelophycus caespitosus, Nitric oxide, Prostaglandin E2, Nuclear factor-_4;B