ppt20170429 itch黄宇翔 耿奇 张楚珩Journal Club GQ_2017 4 29

UncoverItchfromaReceptor,QiGENG29thApril,2017,2,OUTLINE,BackgroundResultsEstablishtheplatformandassaysIdentifyandtestifythereceptorLeadapathforwardSummary&Discussion,3,XinzhongDong,/scientists/xinzhong-dong,ProfessorattheJohnsHopkins(2004-)PostdocatCaltechPhDatUCLAB.S.atWuhanUniversity,4,Mrgpr(Mas-relatedG-coupledproteinreceptor)HighlyspecificinDRGneurons,5,DRG(Dorsalrootganglion),/wiki/Dorsal_root_ganglion,CloselyrelativetosomatosensationSmall-diameterneurons&C-fiberspainanditch,XinzhongDongetal.,2001,Cell,6,CQ-induceditch,CQ(Chloroquine):anti-malaria(疟疾)drugwithterribleside-effectHistamine-independentway,7,OUTLINE,BackgroundResultsEstablishtheplatformandassaysIdentifyandtestifythereceptorLeadapathforwardSummary&Discussion,8,Mrgpr-cluster-/-mice,Targeteddeletion,9,Mrgpr-cluster-/-mice,10,Southernblots,MutantmiceimmunetoCQ,11,nociceptionassays,MutantmiceimmunetoCQ,12,Scratchassays,*SASHmutant,OUTLINE,BackgroundResultsEstablishtheplatformandassaysIdentifyandtestifythereceptorLeadapathforwardSummary&Discussion,13,CQexcitesDRGneurons,14,Ca2+imaging,*EGTACa2+chelatingagent(螯合剂)*RutheniumRedTRPsinhibitor,CQexcitesDRGneurons,15,Patch-clamprecording,MrgprA3(mouse)&MrgprX1(Human),16,MrgprA3/X1selectivelyactivated,17,EC50=27.552.03M,EC50=279.682.10M,DistributionofMrgprA3+neurons,Green:MrgprA3Red:MrgprD,18,RTPCRSingle-cellRTPCR,DRG&Nodoseganglia,KnockdownMrgprA3inDRGneurons,CQ-responsivenesscompletelylostinWTneuronswithsiRNAMrgprA3,19,RNAi,MrgprA3/X1rescuesCQ-responsiveness,20,OUTLINE,BackgroundResultsEstablishtheplatformandassaysIdentifyandtestifythereceptorLeadapathforwardSummary&Discussion,21,MrgprA3+neuronsareitch-sensitive,22,3.6%ofDRGneurons,CQBAM8-22HisCapsaicin,23,Blue:MrgprA3Brown:GRP,MrgprA3+neuronsareitch-sensitive,*GRP:Gastrin-releasingpeptide.GRPR+neuronsarefoundtomediateitchexclusivelyinspinalcord(2007,ZFChengroup),OUTLINE,BackgroundResultsEstablishtheplatformandassaysIdentifyandtestifythereceptorLeadapathforwardSummary&Discussion,24,Summary,TargeteddeletiongeneratesagoodmicemodelMrgprA3/X1isnecessaryforCQ-responseMrgprA3/X1issufficientforCQ-responseMrgprA3/X1reflexesremarkablespecificityMrgprA3+neuronsarelikelytobeitch-specificneurons,25,Discussion,Whatcantheitchreceptorbeusedfor?Milestonebuilton“coincidence”DiscriminateItchfromPainlabeledlinetheoryNextmove?Geneticallyremovethissmallgroupofcells,exchangepainanditchreceptorsRutheniumRedan