Stevioside Suppressed Inflammatory Cytokine Secretion by Downregulation of NFκB and MAPK Signaling

In ammation,Vol.35,No.5,October2012(#2012)DOI:10.1007/s10753-012-9483-0

SteviosideSuppressedIn ammatoryCytokineSecretion

byDownregulationofNF-κBandMAPKSignalingPathwaysinLPS-StimulatedRAW264.7Cells

LiFengyang,1FuYunhe,1LiuBo,1LiuZhicheng,1LiDepeng,1LiangDejie,1ZhangWen,1CaoYongguo,1ZhangNaisheng,1ZhangXichen,1,2andYangZhengtao1,2

Abstract—Stevioside,aditerpeneglycosideisolatedfromSteviarebaudiana,hasbeenreportedtohaveanti-in ammatoryproperties.However,theunderlyingmolecularmechanismsarenotwellunderstood.Theobjectiveofthisstudywastoinvestigatethemolecularmechanismofsteviosideinmodifyinglipopolysaccharide(LPS)-inducedsignalpathwaysinRAW264.7cells.RAW264.7cellswerestimul-atedwithLPSinthepresenceorabsenceofstevioside.Theexpressionofpro-in ammatorycytokineswasdeterminedbyenzyme-linkedimmunosorbentassayandquantitativereal-timepolymerasechainreaction.Nuclearfactor-κB(NF-κB),inhibitorykappaB(IκBα)protein,p38,extracellularsignal-regulatedkinase(ERK),andc-JunN-terminalkinase(JNK)weredeterminedbywesternblot.Theresultsshowedthatsteviosidedose-dependentlyinhibitedtheexpressionoftumornecrosisfactor-α,interleukin-6,andinterleukin-1βinLPS-stimulatedRAW264.7cells.WesternblotanalysisshowedthatsteviosidesuppressedLPS-inducedNF-κBactivation,IκBadegradation,phosphorylationofERK,JNK,andP38.Ourresultssuggestthatsteviosideexertsananti-in ammatorypropertybyinhibitingtheactiv-ationofNF-κBandmitogen-activatedproteinkinasesignalingandthereleaseofproin ammatorycyto-kines.These ndingssuggestthatsteviosidemaybeatherapeuticagentagainstin ammatorydiseases.

KEYWORDS:cytokines;stevioside;nuclearfactor-kappaB(NF-κB);mitogen-activatedproteinkinase(MAPK);RAW264.7cells.

INTRODUCTION

In ammationisamulti-stepprocessthatischarac-terizedbyredness,pain,swelling,anddysfunctionoftheorgans[1].Theprevalenceofin ammatorydiseaseshasbecomeamajorpublichealthconcern.Lipopolysaccha-ride(LPS)asapowerfulbacterialvirulencefactorisacommontriggerofin ammation[2,3].Macrophagesplayanimportantroleinvariousin ammatoryresponsesbyreleasingproin ammatorymediators,suchasnitricoxide,reactiveoxygenspecies,prostaglandinE-2,tumor

LiFengyangandFuYunhecontributedequallytothiswork.

1

CollegeofAnimalScienceandVeterinaryMedicine,JilinUniversity,Changchun,JilinProvince130062,People’sRepublicofChina2

TowhomcorrespondenceshouldbeaddressedatCollegeofAnimalScienceandVeterinaryMedicine,JilinUniversity,Changchun,JilinProvince130062,People’sRepublicofChina.E-mail:xczhang@jluhp.edu.cn;E-mail:yangzhengtao01@sina.com

necrosisfactor-α(TNF-α),interleukin1β(IL-1β),andinterleukin6(IL-6)[4–6].Theseproin ammatorymediatorsleadtoseveretissuedamageandsepticshock.

Stevioside,aditerpeneglycosideisolatedfromSteviarebaudiana,hasbeenreportedtohaveantihyper-glycemic[7],antihypertensive[8,9],andantitumoreffects[10].Recently,ithasbeenshownthatsteviosideexhibitedanti-in ammatoryeffectandshowedtosuppres-sionofin ammatorycytokinesproductioninLPS-stimu-latedTHP-1cellsbyinterferingwiththeIκBkinaseβandNF-κBsignalingpathways[11].Furthermore,steviosidesuppressedTNF-α-inducedIL-8releaseinintestinalcellsbyinhibitingNF-κBactivation[12].However,thedetailmechanismsunderlyingtheanti-in ammatoryeffectofsteviosideinLPS-stimulatedRAW264.7cellsremainunclear.Inthisstudy,wesoughttoexaminetheanti-in ammatoryeffectsofsteviosideinLPS-stimulatedmacrophageandelucidatethepotentialanti-in ammatorymechanism.Theresultsshowedthatsteviosideinhibits

1669

0360-3997/12/0500-1669/0#2012SpringerScience+BusinessMedia,LLC

第1页下一页