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简介：InordertoinvestigatewhetherlipoxinA4(LXA4)hasanantagonisticeffectonlipopolysaccharide(LPS)-inducedsynthesisofinterleukin(IL)-1β,IL-6andIL-8inratpulmonarymicrovascularendothelialcells(PMVEC),andtoexplorethemolecularmechanismsofsignalpathwayinLXA4actions,culturedPMVECweretreatedwithLPS,withorwithoutpreincubationwithLXA4.ProteinsofIL-1β,IL-6andIL-8insupernatantwereanalyzedbyenzyme-linkedimmunosorbentassay(ELISA).ExpressionsofmRNAofIL-1β,IL-6andIL-8weredeterminedbyRT-PCR.Expressionsofphosphorylationofphosphoinositide3-kinase(PI3-K)andmyeloiddifferentiationfactor88(MyD88)wereanalyzedbyWesternblot.ActivitiesofDNA-bindingofnuclearfactor-kappaB(NF-κB)andactivatorprotein-1(AP-1)weremeasuredbyelectrophoreticmobilityshiftassay(EMSA).TheresultsshowedthatLPSinducedproductionofIL-1β,IL-6andIL-8inratPMVECviaMyD88/PI3-K/NF-κBandAP-1pathway-dependentsignaltransduction.LPS-stimulatedexpressionofPI3-K,activitiesofNFκBandAP-1,secretionofproteinandexpressionofmRNAofIL-1β,IL-6andIL-8butnotMyD88expressioninPMVECwereinhibitedbyLXA4inadose-dependentmanner.Inconclusion,LXA4inhibitssynthesisofIL-1β,IL-6andIL-8bydown-regulationofPI3-K/NF-κBandAP-1signalpathwayinPMVEC.

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简介：ToclarifytheroleofAPOBEC3G(A3G)incellulardefenseagainsthepatitisBvirus(HBV),theexpressionofA3GinnormalhumanliverandtheregulationoftheA3Gexpressioninhep-atomacellline(HuH-7)wereinvestigated.ExpressionlevelofAPOBEC3smRNAinhumanliverwasdeterminedbyRT-PCR.HuH-7andHepG2cellsweretreatedwithvariousconcentrationsofIFN-α(0U/ml,100U/ml,500U/ml,1000U/ml)for12h.ThemRNAlevelsweremeasuredbyaquantitativeRT-PCR,theresultswerenormalizedrelativetothespecimenswithoutIFN-αstimulation.TotalproteinofHuH-7cellstreatedwithvariousconcentrationsofIFN-αfor48hwassubjectedtoWesternblotanalysis.Forreportergeneassay,HuH-7cellsweretransfectedwiththereporterplasmidscontainingIRF-Esitesanditsmutantswithdifferentlengths.Thenthecellsweretreatedwithorwithout1200U/mlIFN-aforadditional12h(1000U/ml)after24hoftransfection,andthecelllysatewaspreparedandassayedforluciferaseactivity.ItwasfoundthatnormalhumanliverexpressedthemRNAofA3G.A3GmRNAexpressioninHuH-7andHepG2cellswereup-regulatedbyIFN-αstimulationinadose-depen-dentmanner.WesternblotanalysisindicatedthatA3GproteinexpressionwasalsoenhancedbyIFN-αstimulation.SequenceanalysisshowedtheexistenceofputativesitesofIFNregulatoryfactorelement(IRF-E)in5'regionofA3Ggeneupstreamtheinitiationcodon.IFN-αstimulationresultsin6-to8-foldincreaseinluciferaseactivityincellstransfectedwiththeplasmidcontainingIRF-Esitesofthe5'upstreamsequences,whereasluciferaseactivitydidnotchangeincellstransfectedwiththeplasmidcontainingmutantIRF-EsitesorwithoutIRF-Esites.Asaconclusion,A3Gareexpressedinnormalhumanliver.A3Gexpressionwasup-regulatedbyIFN-αstimulationinhepatomacellsandcouldbeinvolvedinhostdefensemechanismsagainstHBV.ERF-Esitein5'regionofAP0BEC3Ggeneupstreamtheinitiationcodonplaysanimportantroleinthisp

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简介：ExposureofnaivemurineCD4^+TlymphocytestosuperantigensuchasstaphylococcalenterotoxinB(SEB)inducesastrongproliferativeresponse.ProlongedexposureorsubsequentrestimulationoftherespondingTcellpopulationwithSEBleadstotheapoptoticeventsofactivation-inducedcelldeath(AICD).ThesignalingmechanismresponsiblefortheAICDisatargetofintensiveinvestigation.However,theprecisedownstreamsignahngpathwaysofSEB-inducedAICDremainsunclear.Ourresultshereshowthatthesequentialactivationofcaspase-1/ICE-hkeandcaspase-3/CPP32-hkecysteineproteasesprobablyplaysaroleinthesignalingtransductionofSEB-inducedAICD,butcaspase-3/CPP32-hkeproteasesactivationdoesnotdependoncaspase-1-likeproteasesactivation.HerbimycinA,aspecificinhibitorofproteintyresinekinases,inhibitcaspase-3/CPP32-1ikecysteineproteasesactivation.However,itdoesnotpreventDNAfragmentationofCD4^+TcellsapoptosisinducedbySEB.TheseresultsindicatethatproteintyrosinekinasespathwayisprobablyinvolvedinthesignalingtransductionofCD4^+TcellsapoptosisinducedbySEBand“crosstalks”withthepathwayofcaspase-3/CPP32-1ikeproteasesactivation.

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