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-κB 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* and 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: E-mail:
yhchoi@deu.ac.kr
or
immunkim@jejunu.ac.kr Tel: +82 64 754
3427; Fax: +82 64 756 3493
Received: 24 May 2012
Revised accepted: 28 October 2012
Tropical
Journal of Pharmaceutical Research, February 2013;
12(1): 63-70
http://dx.doi.org/10.4314/tjpr.v12i1.11
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 PGE2 by 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-κB.
