Methanol Extract of &lt;i&gt;Polyopes lancifolius&lt;/i&gt; Inhibits the Expression of Pro-inflammatory Mediators in LPSstimulated BV2 Microglia Cells via Downregulation of the NF-&amp;#954B Pathway

Rgtp Jayasooriya,S-Y Park,Yh Choi,G-Y Kim,D-O Moon,C-H Kang

doi:10.4314/tjpr.v11i1.6

Abstract

Purpose: This study is aimed at identifying the anti-inflammatory mechanisms of a methanol extract of Polyopes lancifolius (MEPL) in lipopolysaccharide (LPS)-stimulated BV2 microglia cells.Methods: The expression of mRNA and protein were investigated RT-PCR and western blot analyses in LPS-stimulated BV2 microglial cells. The level of nitric oxide (NO) production was analyzed using Griess reaction. The release of prostaglandin E2 (PGE2) and tumor necrosis factor-α (TNF-α) were determined using sandwich ELISA. NF-κB activation was detected using EMSA methods.Results: MEPL significantly suppressed NO production in LPS-stimulated BV2 cells without any cytotoxicity. The results also indicate that MEPL decreased the production of PGE2 and TNF-α in LPSstimulated BV2 cells. Furthermore, pretreatment with MEPL resulted in a downregulation of LPSinduced mRNA and protein expression of inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2) and TNF-α. Investigation of the effect of MEPL on nuclear factor-κB (NF-κB) activity, which is a potential transcriptional factor for regulating inflammatory genes such as iNOS, COX-2 and TNF-α, showed that MEPL substantially inhibited the LPS-induced DNA-binding activity of NF-κB. MEPL also suppressed the LPS-induced degradation and phosphorylation of I&kappaBα, and it consequently blocked p65 translocation from the cytosol to the nucleus.Conclusion: These data show that MEPL may regulate LPS-induced NO, PGE2, and TNF-α production by suppressing NF-κB activity.Keywords: Polyopes lancifolius, Nitric oxide, Prostaglandin E2, Tumor necrosis factor-α, Nuclear factor-κB

Highlights

Inflammation is an important host response to external challenge or cellular injury, which is mediated by a variety of cell signaling pathways to balance the restoration of tissue structure and function [1]
We investigated the effects of a methanol extract of P. lancifolius (MEPL) on the expression of nitric oxide (NO), prostaglandin E2 (PGE2), and tumor necrosis factorα (TNF-α) in lipopolysaccharide (LPS)-stimulated BV2 microglia cells
Our data revealed that methanol extract of Polyopes lancifolius (MEPL) alone (83 ± 19 pg/ml) sustained PGE2 production compared to the untreated control (80 ± 21 pg/ml)

Summary

Introduction

Inflammation is an important host response to external challenge or cellular injury, which is mediated by a variety of cell signaling pathways to balance the restoration of tissue structure and function [1]. As a result of the activation of these signaling pathways, many genes are expressed that produce different kinds of mediators such as nitric oxide (NO) and prostaglandins, which are generated by inducible isoforms of NO synthase (iNOS) and cyclooxygenase-2 (COX-2), respectively and cytokines such as tumor necrosis factorα (TNF-α) [2]. Several well-characterized cell signaling pathways involve the production of different cytokines and inflammatory mediators. Free NF-κB translocates to the nucleus where it binds to target DNA elements and activates the transcription of genes encoding proteins involved in immune responses, inflammation, or cell proliferation [8]. Many NFκB inhibitors, like non-steroidal antiinflammatory drugs, cell-permeable peptides such as SN-50, and proteasome inhibitors, have been thought as chemotherapeutic agents, because they suppress a variety of inflammatory diseases [9]

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