ppt Rapamycin

Rapamycin通过PKB(蛋白激酶B)和MAPK(促分裂原活化蛋白激酶)激酶途径的激活诱导MKP-1（促分裂原活化蛋白激酶磷酸酶1）表达张莹内科学•CREB（cAMP反应元件结合蛋白）•全称cAMP-responseelementbindingprotein。C端有亮氨酸拉链结构，为DNA结合部位，N端为转录活化部位，包括两个不同的区域，一是磷酸化盒或又称为激酶诱导域，包括多个磷酸化位点，可被多种蛋白激酶如PKA，PKC等磷酸化；另一是存在于P-BOX两侧的富含谷氨酰胺残基的区域，可能与RNA聚合酶的结合有关。•ERK（细胞外调节蛋白激酶）•extracellularregulatedproteinkinases,是MAPK家族的一员，包括ERKl和ERK2,是将信号从表面受体传导至细胞核的关键。它的信号传递途径是涉及调节细胞生长、发育及分裂的信号网络的核心，遵循MAPKs的三级酶促级联反应，即上游激活蛋白→MAPK激酶的激酶（MAPKKK）→MAPK激酶（MAP-KK）→MAPK。在ERKs的传递途径中Ras作为上游激活蛋白，Raf作为MAPKKK，MAPK/ERK激酶（MEK）作为MAPKK，ERK即MAPK，即Ras-Raf-MEK-ERK途径。磷酸化激活的ERKl/2由胞质转位到核内,进而介导Elk-1,ATF,NF-κB,Ap-1,c-fos和c-Jun的转录活化,参与细胞增殖与分化、细胞形态维持、细胞骨架的构建、细胞凋亡和细胞的恶变等多种生物学反应。•Akt•又称PKB或Rac，在细胞存活和凋亡中起重要作用。胰岛素等生长和存活因子都可以激活Akt信号途径。Akt的Ser473可以被PDK1磷酸化。•PI3（磷脂酰肌醇3）Kinase-Akt信号途径是一条经典的信号途径，LY294002等PI3kinase的抑制剂抑制PI3kinase时，通常就会抑制Akt激活。BackgroundMAPkinasephosphatase(MKP)-1playsacriticalroleinregulatinginflammationininnateandadaptiveimmunity.(MKP)-1在固有免疫和获得性免疫的炎症反应调节中发挥着关键性作用。Introduction•Mitogen-activatedproteinkinasephosphatase(MKP)-1,alsoknownasdualspecificityphosphatase双重特异性磷酸酶(DUSP)-1,playsacrucialroleinthedeactivationofMAPkinases.SeveraldrugswithimmunesuppressivepropertiesmodulateMKP-1expressionaspartoftheirmechanismofaction（作用机制）.WeinvestigatedtheeffectofmTORinhibitionthroughrapamycinandadualmTORinhibitor(AZD2014)onMKP-1expression.•LowdoserapamycinledtoarapidactivationofbothAKTandERKpathwayswithasubsequentincreaseinMKP-1expression.•RapamycintreatmentledtophosphorylationofCREB,ATF1转录激活因子1andATF2,threetranscriptionfactorsthatbindtotheCREontheMkp-1promoter.•InhibitionofeithertheMEK（分裂原活化抑制剂）/ERKortheAKTpathwayattenuatedrapamycin-mediatedMKP-1induction.•AZD2014didnotactivateAKTbutactivatedtheERKpathway,leadingtoamoderateMKP-1induction.•Usingbonemarrow-derivedmacrophages(BMDMs骨髓巨噬细胞)derivedfromwildtype(WT)miceormicedeficientinAKT1andAKT2isoformsorBMDMfromtargeteddeficiencyinMEK1andMEK2,weshowthatrapamycintreatmentledtoanincreasedMKP1expressioninBMDMfromWT,butfailedtodosoinBMDMlackingAKT1isoformorMEK1andMEK2.Importantly,rapamycinpretreatmentinhibitedLPS-mediatedp38activationanddecreasednitricoxideandIL-6production.OurworkprovidesaconceptualframeworkfortheobservedimmunemodulatoryeffectofmTORinhibition.mTOR(哺乳动物雷帕霉素靶蛋白)•Mammaliantargetofrapamycin，isamultifunctionalkinasecomplexthatplaysacentralroleincellgrowthandmetabolism.•mTORcaninteractwiththeregulatoryassociatedproteinsofmTOR(raptor)toconstitutethemTORC1complexoralternatively,interactswithrapamycininsensitivecompanion(rictor)toformthemTORC2complex.mTORC1andmTORC2exerttheiractionsbyregulatingseveralimportantkinases,suchasS6K核糖体蛋白S6激酶andAKT.WhileAKTactivatesmTORC1,theTORC2complexdirectlyphosphorylatesAKTatSer473.Rapamycin•anaturalproductofthebacteriumStreptomyceshygroscopicus吸水链霉菌andamacrolideantibiotic大环内脂类抗菌素,hasemergedasapotentantiproliferative抗恶性细胞增生的medicationwithimmunosuppressiveproperties.ThreeprincipalMAPKsubfamilies,includingtheextracellularsignal-regulatedkinases(ERK)1and2,c-Junamino-terminalkinases(JNKs),andp38,areessentialforinitiation启动ofacuteinflammationinresponsetomitogensorstresssignals.WhileactivationofMAPKsisimportantincellularprocesses,failuretoterminate终止thisactivationmayleadtodetrimental不利的systemiceffects全身反应andchronicinflammatorydiseases.MKPsdephosphorylateboththreonineandtyrosineintheTXYmotifonMAPKs,andtherebymodulateinflammation.MKP-1preferentiallydephosphorylatesp38andJNK,whileMKP-3andDUSP-5preferERKsassubstrates.TheMKP-1geneisrapidlyinducedinresponsetogrowthfactors,stress,andseveralcytokines(TNF-αandTGF-β).TheexacttranscriptionalregulationofMKP-1isnotwellunderstood,butithasbeenreportedthatallthreekinases(ERK,p38andJNK)areinvolvedinitsregulation.Additionally,theinductionofMKP-1isrequiredfortheoptimalanti-inflammatoryeffectoftwopotentanti-inflammatorycytokines,IL-10andTGF-β.Moreover,MKP-1isnecessaryinT-cellactivationandfunction.Wehypothesizedthattheimmunosuppressiveeffectofrapamycinis,atleastinpart,duetoup-regulationofMKP-1expression.WeshowthatrapamycinrapidlyactivatesbothAKTandERKpathways(bothinmurinemacrophagesandBMDMs),enhancestheactivitiesofseveraltranscriptionfactorsthatdirectlybindtotheMkp-1promoterandupregulateMKP-1expressioninmacrophages.Moreover,blockingeithertheMEK/ERKpathwayortheAKTpathwayattenuatesrapamycinmediatedMKP-1inductioninresponsetomTORC1inhibition.Finally,weexploretheroleofAKT1and2isoform.ResultsmTORinhibitionleadstoinductionofMKP-1throughtheactivationofAKT1andMEK1/MEK2pathways.RapamycinpretreatmentofmacrophagesinhibitsLPS-mediatedp38activationandIL-6andnitricoxideproduction.ConclusionBothAKT1andMEK1/2regulaterapamycin-mediatedMKP-1induction1.RapamycinpotentlyinducesMKP-1expressionFigure1.Time-dependenteffectofrapamycinonMKP-1expression.2.RapamycinselectivelyactivatesERKpathway.Figure2.RapamycintreatmentactivatesERKbutnotJNKandp383.RapamycinactivatestheAKTandcRAF/MEK/ERKpathways.Figure3.RapamycintreatmentleadstoactivationthePI3/AKTandRAF/MEK1/2/ERKpathways.4.InhibitionofERKandAKTpathwaysattenuatesrapamycin-mediatedMKP-1induction.Figure4.InhibitionofAKTandERK