title: Tiliroside, a dietary glycosidic flavonoid, inhibits TRAF-6/NF-κB/p38-mediated neuroinflammation in activated BV2 microglia.
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 PGE2 production 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 PGE2 production, 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.
  
  
  CONCLUSIONS
  Tiliroside is a potential novel natural compound for inhibiting neuroinflammation in neurodegenerative disorders.
authors.affiliation: Department of Pharmacy, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, United Kingdom.
authors.forename: Ravikanth
authors.initials: R
authors.lastname: Velagapudi
authors.affiliation: Department of Chemistry, Faculty of Science, Obafemi Awolowo University, Ile-Ife, Nigeria.
authors.forename: Mutallib
authors.initials: M
authors.lastname: Aderogba
authors.affiliation: Department of Pharmacy, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, United Kingdom. Electronic address: o.a.olajide@hud.ac.uk.
authors.forename: Olumayokun A
authors.initials: OA
authors.lastname: Olajide
keywords: Antioxidant; NF-κB; Neuroinflammation; TRAF-6; Tiliroside; p38