Methanol
Extract of Myelophycus caespitosus Inhibits the
Inflammatory Response in Lipopolysaccharide-stimulated
BV2 Microglial Cells by Downregulating NF-κB 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
and 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:
Email:
immunkim@jejunu.ac.kr Tel: +82 64 754
3427; Fax: +82 64 756 3493
Received:
26
March 2012 Revised
accepted: 8 October 2012
Tropical
Journal of Pharmaceutical Research, December 2012;
11(6):
917-924
http://dx.doi.org/10.4314/tjpr.v11i6.7
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-κB.
