模式识别受体

InnateImmunerecognition

ThreatstotheindividualProtectionfrommicrobialinvasionNobelPrize2023–innateimmunityNobelPrize2023JulesA.Hoffmann:In1996,found“Toll”genehasaroleinthefly'simmunitytofungalinfections.BruceA.Beutler:in1998,BruceA.BeutlerandcolleaguesdiscoveredthattheToll-likereceptors(TLRs)actastheprincipalsensorsofinfectioninmammals.RalphM.Steinman1973，RalphSteinmanisolateDentriticCell)。DCcanactivateTcell.DCisthebirdgebetweeninnateimmunityandadaptiveimmunity.TollPathwayDrosophilaTheyalldeservetheNobelPrizeRuslanMedzhitovCharlesJaneway1943–2023TakashiFujita,ShizuoAkira

PRRTLRRLRYaleUniv.YaleUniv.KyotoUniv.,OsakaUniv.pathogenassociatedmolecularpatterns,PAMPsConservedpatternfoundonlyinpathogens,notinhostcells。

(CharlesJenaway1989，atColdspringharbor

meeting)TypicalPAMPs：1、Glycans：G-bacteria(lipopolysaccharide,LPS）;G+

bacteria(peptidoglycan)；

Bacterialflagellin2、Nucleotide:VirusDNA/RNA..PAMPsGlucan

Peptidoglycan

LPSFlagellin。。。。patternrecognitionreceptors,PRR：Receptors,onthesurfaceorinsidethecells,forthosepathogenassociatedmoleculepatterns.TypesofPRRs：Toll-likereceptors;TLRsRNA

sensor（RIG-I,MDA5…）DNA

sensor（AIM2，DAI…）NOD-likereceptors；NLRsC-LectinreceptorsOtherPRRs

PRR-PAMPsengagementactivatesphagocytesTolllikeReceptor（TLR）Nature.1997Jul24;388(6640):394-7.AhumanhomologueoftheDrosophilaTollproteinsignalsactivationofadaptiveimmunity.MedzhitovR,Preston-HurlburtP,JanewayCAJr.SourceSectionofImmunobiology,YaleUniversitySchoolofMedicine,NewHaven,Connecticut06520-8011,USA.AbstractWereportherethecloningandcharacterizationofahumanhomologueoftheDrosophilatollprotein(Toll)whichhasbeenshowntoinducetheinnateimmuneresponseinadultDrosophila.LikeDrosophilaToll,humanTollisatypeItransmembraneproteinwithanextracellulardomainconsistingofaleucine-richrepeat(LRR)domain,andacytoplasmicdomainhomologoustothecytoplasmicdomainofthehumaninterleukin(IL)-1receptor.BothDrosophilaTollandtheIL-1receptorareknowntosignalthroughtheNF-kappaBpathway.WeshowthataconstitutivelyactivemutantofhumanTolltransfectedintohumancelllinescaninducetheactivationofNF-kappaBandtheexpressionofNF-kappaB-controlledgenesfortheinflammatorycytokinesIL-1,IL-6andIL-8,aswellastheexpressionoftheco-stimulatorymoleculeB7.1,whichisrequiredfortheactivationofnaiveTcells.PUBMEDsearch“Tolllikereceptor”>24700papers1-1)CellulardistributionofTLRsCellmembraneEndosomemembranePRRs

inPMN1-2)TLRsexpressionincellsImmunecellsandsomeepitheliacellsexpressTLRsTLRsexpressedinimmunecells1-3)StructureofTLRs**Homo-orheterodimers,ortogetherwithothermolecules1-4)TLRs

signalingpathway：MyD88dependentpathway:AllTLRsexcept3MyD88independentpathway:TLR3;partofTLR4↑effectorgenesTLRs

signalingpathway：TLRs

signalingpathway：1.5)NegativeregulationofTLRssignaling1-6)RoleofTLRsinimmuneresponseInnateimmunity:

Activatephagocytosisandkilling:regulatedexpressionofgenesofphagocytosis

Promotingsecretionofcytokines/chemokines:IL1,IL6,TNFa,IFNs,CXCLs,CCLs(recruitotherimmunecells)

Promotesecretionofanti-peptide:eg:Defensins1-6)RoleofTLRsinimmuneresponseAdaptiveimmunity:

TLRsinduceDCmaturation:cytokinesecretion;costimulatorymolecules----DCactivation-presentantigentoactivateTcells

TLRssignalinginfluencesThcelldifferentiation:toinfluencethedifferentiationofTcells:Th1,Th2,Th17

TLRsinduceTregactivation:regulatoryTcellsTregexpressTLR4/5/7/8,TLRsignaldirectlyinvolvedinthebiologicalfunctionofTreg

Bcellactivation(eg:CpGDNATLR9ligandsmaybeusedasadjuvant)2-1）RNAsensors（TLRsandRLRs）RIG-ILikeReceptors（RLR）：RIG-IMDA-5LGP2。。。FujitaTNatImmunol.2023

JImmunol20232-2）structureofRIG-IRIG-I结合5’-pppdsRNAMAVS：adapterforRIG-ISeth,R.B.,Sun,L.,Ea,C.,andChen,Z.J.,"IdentificationandcharacterizationofMAVS:amitochondrialantiviralsignalingproteinthatactivatesNF-κBandIRF3."Cell,122:669-682,2023

Prion-likeproteinfightoffviruses:MAVS,Cell2023UniversityofTexasSouthwesternHHMI2-3）RIG-1/MDA-5

signalingpathway2-4）regulatorofRIG-I/MDA-5Ubiquitin(泛素）对PRR信号旳调整泛素由76个氨基酸残基构成，其中涉及7个赖氨酸残基(K),其C末端可与底物旳赖氨酸残基形成异肽键，从而引起底物泛素化。泛素旳K11、K29、K48和K63均能参加形成泛素与泛素间旳异肽键(Isopeptidebond)。30UbiquitinationforRIG-IsignalingK63泛素化：激活K48泛素化：降解Back3-1）DNA

sensorDNAsensor：TLR9；PolIII；DAI；AIM24-1）NOD

likereceptors（NLRs）NLRs：C端：亮氨酸反复序列（LRR）中间：NACHT：寡聚体化，活化N端：CARD，PYD：相互作用4-2）NLRs

activtesinflammasomePAMP经过NLRs激活炎症反应NLRC4inflammasome邵峰北京生命科学研究所ShaoF.

(2023)

Nature,477,596–600.5-1）C-Lectin

receptorfamilyDectin-1，MannoseReceptors（MRs）5-2）Thefungalpatternreceptor：Dectin-1Onesuchsubfamilyisthe‘Dectin-1cluster’whichisprimarily,butnotexclusively,expressedbymyeloidcells[macrophages,dendriticcells(DC)andneutrophils]。5-2）Thefungalpatternreceptor：Dectin-1BackDectinSignalingPathway葡聚糖甘露聚糖甘露聚糖6-2）otherPRRs清道夫受体（Scavengerreceptors）:结合脂类，LPS等甲酸基多肽受体（Formylpeptidereceptor)：结合含甲酸基旳特殊氨基酸构造补体受体（Complementreceptor）：CrosstalkofPRRsignalingCrosstalkofPRRsignalingPathogenevasionofPRRsignalingpathwayeg:HCVinteractwithPRRsFig1:structureofHCVHCVinteractwithPRRs

PaperDiscussion（1）：RoleofTLR7inWNVinfection(TownTetal.,2023Immunity;IF>20)ssRNA—dsRNA(duringreplication)Fig1:IncreasedSusceptibilityofTlr7−/−andMyd88−/−Mice,butNotTlr9−/−Mice,afterWestNileVirusChallengeWT:50%死亡TLR7-/-:90%死亡TLR7：抗病毒作用Fig2.Tlr7-andMyd88-DependentViralLoadandInnateImmuneCytokineResponsesafterWestNileVirusChallenge：

ViralLoad:↑

Cytokine：IL23,IL12↓

Fig3：ImmuneCellHomingtoWNV-InfectedCellsInVivodependsonTLR7Green：WNV（MoreinTLR7-/-）Red：ImmuneCells(LessinTLR6-/-)ImmuneCellHomingHoming旳意义：1、淋巴细胞得以合理旳再分布及补充；2、增长抗原和淋巴细胞旳接触机会，产生有效旳免疫应答。(免疫细胞有效旳迁移到受感染旳部位)。TLR7dependantmacrophagehomingLesscellinfiltrationFig4.MacrophageHomingtoWestNileVirusIsIL-23SignalingDependentMacrophageVirusHomingIssueBrainsectionstainingSummary:TLR7mediatedanti-WNVfunctionImmuneCellHomingVirusClearancePaperdiscussion(2):Caspase-12controlsWestNilevirusinfectionviatheviralRNAreceptorRIG-I.(WangP.etal.,NatureImmunology2023)Caspase12-/-:Lesssurvival;Severeneurologicalsymptoms1)Viralload↑↑inCaspase12-/-mice2)↓↓INFbproductioninCaspase12-/-mice3)Caspase12interactswithRIG-I/TRIM254)LessUb-RIG-IinCaspase12-/-miceUb-RIG-ITotalRIG-ITotalTRIM25StorySummary:Caspase12isrequiredforRIG-IUb→IFNbproduction（Caspase12旳抗病毒作用）Casp12eg:IFNproductionPaperDiscussion（3）：Toll-likereceptor3mediatesWestNilevirusentryintothebraincausinglethalencephalitis（TLR3helpsthevirus?）WangT.etal.,2023NatureMedicineWT:0%survivalTLR3-/-:40%survivalTLR3旳存在增强了病毒感染2）TLR3-/-micehave↑viralloadinblood;but↓TNFa,IL63)TLR3-/-have↓↓viralinbrain（TLR3-/-血液里virus多，但virus不能有效进入大脑。）4)ReducedbraintissuedamageinTLR3-/-mice炎性细胞渗透降低5）BBBpermeabilityincreasedinWTbutinTLR3-/-miceafterWNVinfection血脑屏障被打开血脑屏障相对完好Virus难以进入TLR3-/-小鼠脑部。6）TNFaisimportantforBBBbreakdown1）TNFa-/-鼠，WNV感染死亡率下降2）IL6-/-鼠，没差别3）TNFa-/-鼠，BBB保持相对完好TNFa是破坏BBB旳细胞因子Summary：TLR3helpsWNVenterthebrainviaTNFa***免疫分子往往是把双刃剑血液------------------大脑Paperdiscussion4:TLRandAgingJImmunol.2023Mar1;184(5):2518-27.PandaA,etal，YaleUniversitySchoolofMedicineAge-associateddecreaseinTLRfunctioninprimaryhumandendriticcellspredictsinfluenzavaccineresponse.Fig1.TLRexpressioninDCsFig2.lesscytokineproductioninoldFig3.VaccineefficiencyinyoungandoldpopulationVaccineefficiencyYoung》》oldResponsestoinfluenzavaccinationinolderadultsandyoungadults.Paper4Summary1.LessTLRexpressioninold2.TLRsignalingarelessresponsiveinold3.DefectofTLRsignalingresultedinvaccinefailureinoldPaperDiscussion5:

DDX24NegativelyRegulatesCytosolicRNA-Mediated

InnateImmuneSignaling

DDX24interactwithFADDIFNinduceDDX24expressionDDX24inhibitIFNproductionSilenceDDX24，IFNproductionincreasedFigure3SiRNA-mediatedknockdownofDDX24enhancesdsRNAinducedRLRsignaling.(G)Genearrayindicatingmostup-regulatedgenesinMEFtreatedwithpolyI:Cat3hoursand9hoursVSnontreatment.Datafrom(A)(B)(C)(D)(E)(F)arepresentedasmeans6s.e.fromthreeindependentexperiments.*indicatesP,0.05.**indicatesP,0.01.Figure4.SiRNA-mediatedknockdownofDDX24inhibitsVSVreplication.Figure4.SiRNA-mediatedknockdownofDDX24inhibitsVSVreplication.(F)Lossof