Tropical Journal of Pharmaceutical Research

Original Research Article | OPEN ACCESS

Inhibition of Nitric Oxide and Prostaglandin E2 expression by Methanol Extract of Polyopes affinis in Lipopolysaccharide-stimulated BV2 Microglial Cells through Suppression of Akt-dependent NF-kB Activity and MAPK Pathway

Rajapaksha Gedara Prasad Tharanga Jayasooriya¹, Yeon-Jeong Jang¹, Chang-Hee Kang¹, Matharage Gayani Dilshara¹, Dong-Oh Moon², Taek-Jeong Nam³, Yung Hyun Choi⁴ , Gi-Young Kim¹

¹Laboratory of Immunobiology, Department of Marine Life Sciences, Jeju National University, Jeju 690-756; ²Department of Biology Education, College of Education, Daegu University, Gyeongsan, Gyeongbuk 712-714; ³Department of Food Science and Biotechnology, Pukyong National University, Busan 608-737; ⁴Department of Biochemistry, College of Oriental Medicine, Dongeui University, Busan 614-051, Republic of Korea.

For correspondence:- Yung Choi Email: yhchoi@deu.ac.kr Tel:+82647543427

Received: 24 May 2012 Accepted: 28 October 2012 Published: 21 February 2013

Citation: Jayasooriya RG, Jang Y, Kang C, Dilshara MG, Moon D, Nam T, et al. Inhibition of Nitric Oxide and Prostaglandin E2 expression by Methanol Extract of Polyopes affinis in Lipopolysaccharide-stimulated BV2 Microglial Cells through Suppression of Akt-dependent NF-kB Activity and MAPK Pathway. Trop J Pharm Res 2013; 12(1):63-70 doi: 10.4314/tjpr.v12i1.11

© 2013 The authors.
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Abstract

Purpose: To determine whether the methanol extract of Polyopes affinis (MEPA) down-regulates the expression of pro-inflammatory mediators in lipopolysaccharide (LPS)-stimulated BV2 microglial cells.

Methods: The production of nitric oxide (NO) and prostaglandin E₂ (PGE₂) was measured by the Griess reagents and enzyme-linked immunosorbent assay (ELISA), respectively. expression levels of mRNA and protein in LPS-stimulated BV2 microglial cells were assessed by reverse transcription-polymerase (RT-PCR) and Western blot analysis. Activation of nuclear factor-κB (NF-κB) was detected by electrophoretic mobility shift assay (EMSA).

Results: MEPA inhibited the expression of 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 accompanying cytotoxicity. Moreover, treatment with MEPA significantly suppressed the LPS-induced DNA-binding activity of NF-κB, which is known as a main transcription factor for the regulation of pro-inflammatory genes, as well as the nuclear translocation of its subunit p65 and p50, by degrading IκBα. MEPA increased Akt dephosphorylation which leads to suppression of the DNA-binding activity of NF-κB in LPS-stimulated BV2 microglial cells and suppressed phosphorylation of ERK and JNK, which are involved in the mitogen-activated protein kinase (MAPK) signaling pathway for regulating pro-inflammatory genes.

Conclusion: Our results indicate that MEPA down-regulates pro-inflammatory mediators such as NO and PGE₂by suppressing Akt-dependent NF-κB activity as well as phosphorylation of ERK and JNK in LPS-stimulated BV2 microglial cells.

Keywords: Polyopes affinis, Nitric oxide, Prostaglandin E2, Nuclear factor-_4;B