分子医学-炎症、感染与相关疾病

分子医学（MolecularMedicine）炎症、感染与相关疾病2Infection感染Immunityisthebody’ssolutiontoprotectitselffromInfectiousDiseasesCommensalflora(共生菌群):staph,strep,pneumonia(葡萄球菌，链球菌，肺炎)Opportunisticpathogens(条件致病菌):candida,Clostridiumdifficile

(念珠菌，艰难梭状芽胞杆菌)Truepathogens(致病菌):Influenza3ContentsBriefintroductionofInfectiousDiseasesBacteriainfectionandInnateImmunityagainstbacteriainfectionViralinfectionandInnateImmunityagainstviralinfection4BriefintroductionofInfectiousDiseases1951年中国城市居民前10位死因:

肺炎;中枢神经系之血管病变;胃炎,十二指肠炎,肠炎及大肠炎;心脏疾病;恶性肿瘤;周产期之死因;结核病;意外灾祸;自杀及自伤;肾炎及肾水肿5InfectiousdiseasesisstillamajorprimarycausesofdeathworldwideMorensDMetal.,Nature2004,430:242-9.6Emergingandre-emerginginfectiousdiseasesMorensDMetal.,Nature2004,430:242-9.7InnateimmunityagainstPathogenicMicrobes

Bacteria:

Virus

Fungi8BacteriaFACTS:largenumbersofsingle-celledprokaryotemicroorganisms.2.Typicallyafewmicrometersinlength;3.Everywhereinearth:water,soil,aswellasinlivebodiesofplantsandanimals4.10millioninagramofsoil;amillionin1Lwater,5×1030onearth;10timescellnumbersinhumanflora(菌群).BacteriaInfection9BacteriaFACTS:5.Thevastmajorityofthebacteriainthebodyarerenderedharmlessbytheprotectiveeffectsoftheimmunesystem,andafewarebeneficial.6.Afewspeciesofbacteriaarepathogenicandcauseinfectiousdiseases,includingcholera,syphilis,anthrax,leprosyandbubonicplague(霍乱，梅毒，炭疽，麻风病和鼠疫).Themostcommonfatalbacterialdiseasesarerespiratoryinfections,withturberculosisalonekillingabout2millionpeopleayear.7.Antibioticsareusedtotreatbacterialinfectionsandinagriculture,soantibioticresistanceisbecomingcommon.8.Inindustry,bacteriaareimportantinsewagetreatment,theproductionofcheeseandyogurtthroughfermentation,aswellasinbiotechnology,andthemanufactureofantibioticsandotherchemicals.10Endotoxin:EndotoxinsaretoxinsassociatedwithcertainGram-negativebacteriawhicharestructuralmoleculesofthebacteriathatisrecognizedbytheimmunesystem.Theprototypicalexamplesofendotoxinarelipopolysaccharide(LPS).Exotoxin:Toxinsexcretedbyamicroorganism,includingbacteria,fungi,algaeandprotozoa.Anexotoxincancausedamagetothehostbydestroyingcellsordisruptingnormalcellularmetabolism.Theyarehighlypotentandcancausemajordamagetothehost.PathogenesisofBacteriaInfection11ExotoxinsofBacteriaInfection12DiseasesfromBacteriaInfection13固有免疫适应性免疫14RecognitionOpsonization,phagocytosisDestructionMemoryInnateimmunity

Phagocytes Macrophages

Dendriticcells

Neutrophils

Receptors Toll-likereceptors C-typelectinreceptors

Cytosolic NODproteins RNAhelicases DNArecognition Mediators

InflamatorycytokinesAdaptiveimmunity

Humoral Antibodies Cellular TcellsMicrobialrecognitionininnateimmunereceptorsInvertebrates/VertebratesVertebrates15RecognitionofMicrobeproductsbyPAMPSPathogen-associatedmolecularpatterns,orPAMPs,aremoleculesassociatedwithgroupsofpathogensrecognizedbycellsoftheinnateimmunesystem.Thesemoleculescanbereferredtoassmallmolecularmotifsconservedwithinaclassofmicrobes.Theyarerecognizedbypatternrecognitionreceptors(PRRs)likeToll-likereceptors(TLRs)inbothplantsandanimals.16BacterialLipopolysaccharide(LPS)onbacterialcellmembrane(Gram-)Bbacterial

flagelinPeptidoglycanandlipoteichoicacid(磷脂壁酸)fromGrampositivebacteriaUnmethylated

CpGDNA。。。

PAMPsfrombacteria17Toll-likereceptors(TLRs;transmembranereceptors)RIG-I-likereceptors(RLRs;cytoplasmicRNAhelicases)NOD-likereceptors(NLRs;cytoplasmicsensors)C-typelectinreceptors(CLRs;transmembranereceptors)Pattern

RecognitionReceptors（PRRs）18Recognitionofpathogen-associatedmolecularpatternsbyPRRs19DrosophilaTollIdentifiedaproteincalled“Toll”meaning“weird”HelpstheDrosophilaembryotodifferentiateitstopfromitsbottom

(Neuraltubedevelopment)http:///genomics/papers/drosophila.html

20TollandInnerPartofHumanIL-1RisSimilarSearchingforproteinssimilartoTollShowscytoplasmicdomainofTollrelatedtothatofhIL-1RIdentityextendsfor135aaDidn’tmakesenseWhydoesaproteininvolvedinhumaninflammationlooklikeoneinvolvedinflyneuraltubedevelopment?21FliesuseTolltoDefendfromFungiInfectedTl-deficientadultflieswithAspergillus

fumigatusAllfliesdiedafter2-3daysFliesuseTolltodefendfromfungiThus,inDrosophila,Tollseemstobeinvolvedinembryonicdevelopmentandadultimmunity22SurvivalrateofadultDrosophilainfected

withAspergillusfumigatusinToll-23FliesuseTolltoDefendfromFungiDrosophilahasnoadaptiveimmunesystemThereforeneedsarapidantimicrobialpeptideresponseTwodistinctpathwaystoactivateantimicrobialpeptidegenesinadultsMutationsinTollpathwayreducesurvivalafterfungalinfection24HumanTollDiscoveryIninsect,IL-1receptorandtheTollproteinareonlysimilarinthesegmentswithinthecellhumanproteinsthattotallyresembletoTollwerelaterdiscovered25HumanTollDiscoveryAlignmentofthesequencesofhumanandDrosophilaTollproteinsHomologyovertheentirelengthoftheproteinchainshTollgenemoststronglyexpressedinSpleenandPBL(peripheralbloodleukocytes)26TLRs:Toll-likeReceptorsdiacyl-triacyl-lipopeptide

酰基脂肽；flagellin:鞭毛蛋白;LPS:脂多糖(Lipopolysaccharides)

27LPSistheligandforTLR4LargemoleculesfoundinoutermembraneofGram-negativebacteriaComprisedofalipidandsaccharidecomponentHighlyimmunogenicRecognizedbyTLR4CancausesepticshockandleadtodeathOftenreferredtoasEndotoxinsinceitisnotsecretedbutisabyproductofbacteriallysis28TLR4ActivatedbyLPSNormalmicedieofsepsisafterbeinginjectedwithLPSC3H/HeJmicehavedefectiveresponsetoLPSandsurviveMissensemutationaffectingthecytoplasmicdomainofTLR4Majorbreakthroughinthefieldofsepsis–molecularmechanismthatunderliesinflammationrevealed29LPS30LPS31/nobel_prizes/medicine/laureates/2011/#32TLRs:Structure33LigandRecognitionTLR3-dsRNA34LigandRecognitionTLR4/MD2–LPS35MyD88-dependentandindependentpathway36

CytoplasmictailsofTLRsshowsimilaritiestoIL-1receptor(TIR)CommonadaptortoTLRsisMyD88CrucialprolineresidueinallTLRTIRdomains,exceptTLR3Ifmutatedordeleted,nosignalingoccursAllTLRslikelyhaveaMyD88pathway(TLR3isanexception)TLR4hasaMyD88independentpathwayaswellCytoplasmicTIRdomainTLRsandTIRDomain37MyD88knockoutmicehavenoresponsetoLPSMyD88isessentialtoallinflammatorysignalingpathwaysMyD88s,asplicevariantofMyD88downregulatestheinflammatoryresponseMyD88interactswithTIRdomainofTLRandrecruitsIRAK-4,IRAK-1andTRAF-6MyD88AdaptorRakoff-Nahoumetal.,Recognitionofcommensal

microflorabyToll-likereceptorsisrequiredforintestinalhomestasis.Cell118:229-41,2004.384IRAKsknown,IRAK1,IRAK-2,IRAK-MandIRAK-4IRAKareserine/threonine

kinasesIRAK-4phosphorylatesIRAK-1IRAK-MplaysaninhibitoryroleinTLRsignalingTRAF6isamemberoftheTNFreceptorassociatedfactor(TRAF)familyTRAF6interactswithIRAK-1andgetsactivatedReleaseofTRAF6/IRAK-1ensuessubsequentsignalingIRAKandTRAF6IL-1RI-associatedproteinkinases(IRAKs)tumornecrosisfactorreceptor-associatedfactor6(TRAF6).39TRAF6/IRAK-1complexassociateswith3proteinsTAK1(TGF-Bactivatedkinase)TAB1(TAK1bindingproteins)TAB2(TAK1bindingproteins)LargecomplexassociateswithmembraneEventuallyIRAK-1staysinmembranewhileTRAF6/TAK1/TAB1/TAB2movetocytosolE2LigasessuchasUbc13andUev1AjoinfurtherenlargingcomplexIRAKandTRAF6Release40TAK-1ActivationTheenlargedcomplexthatincludesTRAF6,TAK1,TAB1,TAB2,Ubc13,Uev1AactivateTAK1ActivatedTAK1phosphorylatesIKKcomplexActivatedTAK1canalsophosphorylateMAPKinases

IKKcomplexconsistsofIKK,and/NEMOIBphosphorylationresultsinNF-Btranslocationtonucleus41OverviewofMyD88-dependentpathway42MyD88IndependentPathwayMyD88KnockoutmicedonotproduceinflammatorycytokinessuchasTNF-

HoweverwithTLR4stimulationNF-BandJNKdelayedactivityoccursThisstronglysuggeststheexistenceof2pathwaysinTLRsignalingaMyD88dependentpathwayaMyD88independentpathwayTLR3stimulationalsoexchibitsaMyD88independentpathwayTLR443OverviewofTLRsignaling4445InflammationCytokinesChemokinesFluidsProteinsBacteriatriggermacrophagestoreleasecytokinesandchemokinesVasodilationandincreasedvascularpremeabilitycauseredness,heat,andswellingInflammatorycellsmigrateintotissue,releasinginflammatorymediatorsthatcausepain46InflammationInflammationispartofthecomplexbiologicalresponseofvasculartissuestoharmfulstimuli,suchaspathogens,damagedcells,orirritants.Inflammationisaprotectiveattemptbytheorganismtoremovetheinjuriousstimuliandtoinitiatethehealingprocess.FourMajorSymptomsofInflammation:1.Redness2.Pain3.Heat4.SwellingMayalsoobserve:5.Lossoffunction47FunctionsofInflammationDestroyandremovepathogens(aswellasdamagedselftissuesandcells).Ifdestructionisnotpossible,tolimiteffectsbyconfiningthepathogenanditsproducts.Repairandreplacetissuedamagedbypathogenanditsproducts.48InflammationmediatedbycytokinesLowmolecularweight,solubleproteinsthatareproducedinresponsetoanantigenandfunctionaschemicalmessengersforregulatingtheinnateandadaptiveimmunesystemInnateimmunesystemMacrophagesandDendriticcellsTumornecrosisfactor-alpha(TNF-)Interleukin-1(IL-1)Interleukin-12(IL-12)Adaptiveimmunesystem……………49InflammationPro-inflammatorycytokines(TNF,IL-1)signaltoendothelialcellstomakethem:Leakytofluid(influxofplasma;containingantibodies,complementcomponents,etc.)Stickyforleukocytes,leadingtoinfluxofneutrophilsfirst,thenmonocytes,lymphocytesSystemiceffects:fever,acutephaseresponse50Sepsis(Septicshock)BacterialsepticemialeadstoactivationofTLRsonmonocytesinthebloodSystemicreleaseofTNFandIL-1leadsto“inflammation”alloverthebodyShockfromlossofbloodpressure(vasodilationandleakageoffluidintotissues)Thecombinationofeffectscanleadtomulti-organfailureanddeathBacteriaInfectionafterinjury—SepsisinEmergencyRoomNeonatalSepsis51NegativeRegulationofToll-likereceptorsignaling52SolubleTLRs53Membrane-associatedRegulators54FeedbackRegulationofIntracellularsignaling55NLRTheNOD-likereceptors(NLRs)arecytoplasmicproteinsthathaveavarietyoffunctionsinregulationofinflammatoryandapoptoticresponses;TheofficialdefinitionofNLRiscurrently"Nucleotide-bindingdomain,Leucine-Richrepeatcontaining"proteinsincetheseproteinsarecomposedofconserved"modules"includingacentralnucleotide-bindingoligomerizationdomainandaseriesoftandemleucine-richrepeats.NLRsareencodedbyalargegenefamiliesinmanydifferentanimalspecies;therearemorethan20NLRgenesinhumans.Manyarethoughttoserveaspatternrecognitionreceptors(PRRs)whichsensemicrobialproductsinthecytoplasmofcells,althoughsomemembershavedifferentfunctions.56NOD1&NOD2recognizepeptidoglycansubstructuresandpromoteinnateimmuneresponsesNOD1andNOD2areintracellularmoleculesandresemblesomeplantdiseaseresistanceproteins;bestunderstoodofthe“NOD-likereceptors”orNLRs

57NLR

signalingCARD

Domains：Caspaserecruitmentdomains58ProcessingofIL-1andrelatedcytokinesbyinflammasome:animportantregulatorystepSome“NLRs”assembletoformthe“inflammasome”whichproteolyticallyprocessesIL-1andrelatedcytokinestotheiractive,secretedforms.InflammasomeinactivatedbycellularstressorrecognitionofmicrobialcomponentsinthecytoplasmGeneticperiodicfeversyndromesareduetoactivatingmutationsininflammasome59NOD-likereceptor(NLR)familymemberssuchasNALPs,NAIP,andIPAFTheLRRofNALP3orIPAFsensetheactivatingsignalsleadingtotheoligomerization

oftheNACHTregion.TheexposedPYDandCARDdomaincanrecruitadaptorproteinASCandCARD-containingcaspasestoformadonutshapecomplex.TheIL-1β-processingcaspaseactivitymostlikelyfacetheinsideofthedonut(lowerpanel).NACHTPYDCARD60Two

signalsareessentialforIL-1secretion61InnateImmunityagainstViralinfection62Viralinfection:Avirusisasmallinfectiousagentthatcanreplicateonlyinsidethelivingcellsoforganisms.EntrymediatedbyCellsurfaceReceptors:ViralInfectionVirus

receptor

celltypeHIV CD4 ThcellsEBV CR2 BcellsInfluenza sialicacid manycelltypesRhinovirus ICAM-1 manycelltypesPoliovirus poliovirusreceptor neuronsMeasles CD46 manycelltypesHHV6 CD46 manycelltypes 63GeneralProcessofViralInfection:ViralInfectionAttachmentPenetrationUncoatingReplicationself-assemblyRelease64Celldamagesmediatedbyviralinfection-EffectsonthehostcellMostvirusinfectionseventuallyresultinthedeathofthehostcell.Thecausesofdeathincludecelllysisandapoptosis。Oftencelldeathiscausedbycessationofitsnormalactivitiesbecauseofsuppressionbyvirus-specificproteinsSomevirusescausenoapparentchangestotheinfectedcell（latentinfection）.Thiscausespersistentinfectionsandthevirusisoftendormantformanymonthsoryears.Thisisoftenthecasewithherpesviruses.Someviruses,suchasEpstein-Barrvirus,cancausecellstoproliferatewithoutcausingmalignancy,whileothers,suchas,papilloma

viruses(HPV

乳头状瘤病毒)areestablishedcausesofcancer.ViralInfection65ViralInfection66ViralNucleicAcidsrecognizedbyTLRs67ViralNucleicAcidsrecognizedbyTLRs68RecognitionofcytosolicviralRNAsbyRLRsRIG-I-likereceptors(RLRs),alsoknownasRIG-I-likehelicases(RLHs)constituteafamilyofcytoplasmicRNAhelicasesthatarecriticalforhostantiviralresponses.

RIG-I(retinoic-acid-inducibleprotein1,alsoknownasDdx58)andMDA-5(melanoma-differentiation-associatedgene5,alsoknownasIfih1orHelicard)sensedouble-strandedRNA(dsRNA),areplicationintermediateforRNAviruses,leadingtoproductionoftypeIinterferons(IFNs)ininfectedcells.

69RIG-IandMDA-5containaDExD/HboxRNAhelicaseandtwocaspaserecruitingdomain(CARD)-likedomains.ThehelicasedomaininteractswithdsRNA,whereastheCARDdomainsarerequiredtorelaythesignal.

RIG-IparticipatesintherecognitionofParamyxoviruses(Newcastlediseasevirus(NDV),Sendaivirus(SeV)),Rhabdoviruses(vesicularstomatitisvirus(VSV)),Flaviviruses(hepatitisC(HCV))andOrthomyxoviruses(Influenza).MDA-5isessentialfortherecognitionofPicornaviruses(encephalo-myocarditisvirus(EMCV))andpoly(I:C),asyntheticanalogofviraldsRNA.

Notably,RIG-IbindsspecificallytosinglestrandedRNAcontaining5’-triphosphatesuchasviralRNAandinvitro-transcribedlongdsRNA[4].MammalianRNAiseithercappedorcontainsbasemodificationssuggestingthatRIG-Iisabletodiscriminatebetweenselfandnon-selfRNA.RIG-IbindspreferentiallytoshortdsRNAwhileMDA-5recognizespreferentiallylongdsRNA.70ViraldsRNAisalsorecognizedbyToll-Likereceptor3(TLR3)whichisexpressedonthecellsurfacemembraneorendosomes.

RecognitionofdsRNAbyRIG-I/MDA-5orTLR3iscell-typedependent.StudiesofRIG-I-andMDA-5-deficientmicehaverevealedthatconventionaldendriticcells(DCs),macrophagesandfibroblastsisolatedfromthesemicehaveimpairedIFNinductionafterRNAvirusinfection,whileproductionofIFNisstillobservedinplasmacytoid

DCs(pDCs).ThusincDCs,macrophagesandfibroblasts,RLRsarethemajorsensorsforviralinfection,whileinpDCs,TLRsplayamoreimportantrole.RLRs

vsTLR3711.IFNisinducedbyviralinfection.2.IFNbindstospecificcellsurfacereceptorsandactivateintracellularsignalingpathways.3.IFNsignalindu