Tiliroside, a dietary glycosidic flavonoid, inhibits TRAF-6/NF-κB/p38-mediated neuroinflammation in activated BV2 microglia

Ravikanth Velagapudi, Mutallib Aderogba, Olumayokun A. Olajide

Research output: Contribution to journalArticle

43 Citations (Scopus)

Abstract

Background: Tiliroside is a dietary glycosidic flavonoid which has shown in vivo anti-inflammatory activity. This study is aimed at evaluating the effect of tiliroside on neuroinflammation in BV2 microglia, and to identify its molecular targets of anti-neuroinflammatory action.

Methods: BV2 cells were stimulated with LPS + IFNγ in the presence or absence of tiliroside. TNFα, IL-6, nitrite and PGE2production was determined with ELISA, Griess assay and enzyme immunoassay, respectively. iNOS, COX-2, phospho-p65, phospho-IκBα, phospho-IKKα, phospho-p38, phospho-MK2, phosopho-MKK3/6 and TRAF-6 were determined by western blot analysis. NF-κB activity was also investigated using a reporter gene assay in HEK293 cells. LPS-induced microglia ROS production was tested using the DCFDA method, while HO-1 and Nrf2 activation was determined with western blot.

Results: Tiliroside significantly suppressed TNFα, IL-6, nitrite and PGE2production, as well as iNOS and COX-2 protein expression from LPS + IFNγ-activated BV2 microglia. Further mechanistic studies showed that tiliroside inhibited neuroinflammation by targeting important steps in the NF-κB and p38 signalling in LPS + IFNγ-activated BV2 cells. This compound also inhibited LPS-induced TRAF-6 protein expression in BV2 cells. Antioxidant activity of tiliroside in BV2 cells was demonstrated through attenuation of LPS + IFNγ-induced ROS production and activation of HO-1/Nrf2 antioxidant system.

Conclusions: Tiliroside inhibits neuroinflammation in BV2 microglia through a mechanism involving TRAF-6-mediated activation of NF-κB and p38 MAPK signalling pathways. These activities are possibly due, in part, to the antioxidant property of this compound.

General Significance: Tiliroside is a potential novel natural compound for inhibiting neuroinflammation in neurodegenerative disorders.

Original languageEnglish
Pages (from-to)3311-3319
Number of pages9
JournalBiochimica et Biophysica Acta - General Subjects
Volume1840
Issue number12
Early online date23 Aug 2014
DOIs
Publication statusPublished - Dec 2014

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