胆固醇代谢课件

胆固醇代谢平衡调控胆固醇代谢提纲胆固醇的生物学功能胆固醇相关疾病胆固醇的生物合成胆固醇在血液中的运输家族型高胆固醇血症NPC疾病胆固醇的降解与清除胆固醇代谢的负反馈调控机制—SCAP-SREBP途径胆固醇代谢的负反馈调控机制—HMGCR降解途径饮食胆固醇吸收的分子途径胆固醇代谢Cholesterol（胆固醇）胆固醇代谢一、胆固醇的生物学功能MembraneFluidityBileAcidsHormones、VitaminDSynapseHedgehogModificationSignalTransduction……胆固醇代谢哺乳动物细胞模式图胆固醇代谢膜上的微结构域胆固醇代谢Cholesterolandcholesterolderivatives

雌激素雄激素胆固醇代谢胆固醇代谢脂肪酸、糖等提供能量（ATP）胆固醇并不提供能量胆固醇代谢二、胆固醇相关疾病胆固醇代谢Cholesterolisthemajorcauseofatherosclerosis胆固醇代谢心脑血管疾病恶性肿瘤肺炎、流感感染性疾病意外死亡慢性阻塞性肺病肝病及肝硬化糖尿病肾病其它43.8%22.3%FromHeJ.etal.,NEnglJMed,(2005),353:1124-1134.中国死亡原因统计胆固醇代谢蒙娜丽莎患有高胆固醇？意大利帕勒莫大学的病理解剖学教授弗兰克，研究认为蒙娜丽莎饮食不健康，患有高胆固醇症。正是眼部的脂肪瘤，造成了蒙娜丽莎这副神秘莫测的表情。画中的她（或者说达芬奇的这个模特）正在为自己体内过高的胆固醇而担忧。胆固醇代谢胆结石老年痴呆症CholesterolandDiseasesNiemann-PickTypeCDisease糖尿病/肥胖症胆固醇代谢FromIMSHealth,MIDAS

药品销售排行榜NameCompanyIndicationSalestoJune07($bn)LipitorPfizerHypercholesterolaemia（高胆固醇血症）13.5NexiumAstraZenecaGastroesophagealreflux（胃食管返流）,gastriculcers（胃溃疡）6.9SeretideGSKAsthma（哮喘）6.7PlavixBristol-MyersSquibbAtheroscleroticevents（动脉粥样硬化症）5.8AranespAmgenAnaemia（贫血症）5.1胆固醇代谢三、胆固醇的生物合成胆固醇代谢CholesterolisnotrequiredinthedietCholesterolisanessentialmoleculebutisnotrequiredinthedietbecauseallcellscansynthesizeitfromsimpleprecursors胆固醇代谢Cholesterolismadefromacetyl-CoAinfourstagesallofitscarbonatomsareprovidedbyasingleprecursor–acetate胆固醇代谢Stage1Threeacetateunitscondensetoformasixcarbonintermediate,mevalonate胆固醇代谢Twomoleculesofacetate-CoAcondenseformingacetoacetyl-CoA.Acetoacetyl-CoAcondenseswithacetyl-CoAtoyieldb-hydroxy-b-methylglutaryl-CoA(HMG-CoA)胆固醇代谢ThefinalstepthereductionofHMG-CoAtomevalonate,catalyzedbyHMG-CoAreductase.胆固醇代谢Stage2ConversionofmevalonateintoactivatedisopreneunitsIsoprenecontainingmoleculesareimportantintermediatesincholesterolbiosynthesis胆固醇代谢Stage3Polymerizationofsix5-carbonisopreneunitstoformthe30-carbonlinearstructureofsqualene.胆固醇代谢Cyclizationofsqualeneformsthefourringsofthesteroidnucleus.Subsequentmodificationsleadstothefinalproduct,cholesterol.Stage4胆固醇代谢胆固醇代谢MostofthecholesterolmadeintheliverisexportedMuchofcholesterolsynthesistakesplaceinthe

liverMostisexported胆固醇代谢Cholesterolisexportedinthreeforms1.Bilesalts–amphipathiccholesterolderivativesthataidlipiddigestion2.Cholesterol–tobile3.Cholesterylesters–transportedandsecretedin lipoproteinparticlestoother tissuesthatusecholesterol orarestoredintheliver胆固醇代谢四、胆固醇在血液中的运输胆固醇代谢CholesterylesterformationFormedintheliverConvertingcholesteroltoamorehydrophobicform胆固醇代谢Cholesteroltransport:theproblemCholesterolandcholesterylestersareessentiallyinsolubleinwaterThesemoleculesmustbemovedfromthetissueoforigintothetissuesinwhichtheyarestoredorareconsumed胆固醇代谢Cholesteroltransport:thesolutionCholesterolandcholesterylestersarecarriedinthebloodplasmafromonetissuetoanotherasplasmalipoproteins胆固醇代谢Cholesterolestersentercellsby

receptormediatedendocytosis胆固醇代谢五、家族型高胆固醇血症LDLreceptor(LDLR)突变胆固醇代谢家族性高胆固醇血症(FamilialHypercholesterolemia,FH)杂合子患者血清总胆固醇较正常人高出1～2倍纯合子患者血清总胆固醇较正常人高出6～8倍杂合子患者发生率为1/500纯合子患者发生率为1/1,000,000杂合子患者男性30～40岁时，患CAD，23%患者在50岁以前死于CAD，>50%患者在60岁时明显的CAD症状；纯合子患者十几岁时，有严重的心血管事件甚至死亡胆固醇代谢LDLR突变----黄色瘤胆固醇代谢FH患者LDLR突变----眼底脂质渗出正常人胆固醇代谢六、

Niemann-PicktypeC(NPC)疾病溶酶体堆积型疾病（LysosomalStorageDisorders）胆固醇在溶酶体中堆积进行性神经细胞死亡、肝脾肿大、小脑共济失调、痴呆、语言吞咽困难、青春期之前死亡1：120，000发病，携带者1：100NPC1（大的膜蛋白）或NPC2（小的可溶蛋白）基因突变临床尝试用环化糊精进行治疗胆固醇代谢正常细胞NPC1突变细胞胆固醇代谢胆固醇代谢胆固醇代谢七、胆固醇的降解与清除胆固醇代谢DegradationofcholesterolTheringstructureofcholesterolcannotbemetabolizedtoCO2andH2OinhumansTheintactsterolringiseliminatedfromthebodyby:Conversiontobileacids,whichareexcretedinfecesSecretionofcholesterolintothebile,whichtransportsittotheintestineforelimination胆固醇代谢SteroidhormonesareformedfromcholesterolAllsteroidhormonesarederivedformcholesterolInthecortexofadrenalglandstwoclassesofhormonesaresynthesized–mineralocorticoidsandglucocorticoidsInthemaleandfemalegonads–sexhormonesareproducedSexhormonesinclude–progesterone,androgensandestrogens胆固醇代谢八、胆固醇代谢的负反馈调控机制（一）SCAP-SREBP途径胆固醇代谢胆固醇代谢脂质代谢的关键蛋白质及其功能调控的临床意义LDLReceptorsLDLHMGCRSREBPPathwayHMGCRinhibitor胆固醇代谢Insig胆固醇代谢SREBP—膜结合的转录因子WangX,BriggsMR,HuaX,YokoyamaC,GoldsteinJL,BrownMS.Nuclearproteinthatbindssterolregulatoryelementoflowdensitylipoproteinreceptorpromoter.II.Purificationandcharacterization.JBiolChem.1993Jul5;268(19):14497-504.YokoyamaC,WangX,BriggsMR,AdmonA,WuJ,HuaX,GoldsteinJL,BrownMS.SREBP-1,abasic-helix-loop-helix-leucinezipperproteinthatcontrolstranscriptionofthelowdensitylipoproteinreceptorgene.Cell.1993Oct8;75(1):187-97.WangX,SatoR,BrownMS,HuaX,GoldsteinJL.SREBP-1,amembrane-boundtranscriptionfactorreleasedbysterol-regulatedproteolysis.Cell.1994Apr8;77(1):53-62.胆固醇代谢胆固醇代谢25-Hydroxycholesterol-irradiationMutantcellssurvive(25-RA)胆固醇代谢AmphotericinB-irradiationCholesterolauxotrophs(M19)HumanfibroblasmgenomicDNAtoM19cellsHfT1M19(c)Growinlipid-deficientmediumGrowinlipid-deficientmediumHfT1M19(c)genomicDNAtoM19cellsHfT2M19(c)Growinlipid-deficientmediumHfT2M19(c)genomicDNAtoM19cellsHfT3M19(c)Inter-AluPCR,usethisprobetoscreengenomicPAClibrary,transfectPACcloneintoM19,sequencePACcloneandcomparewithEST.胆固醇代谢S2PcDNAtoCHOcellsBrieflyincubatedwithLDL,AmphotericinBselection-irradiationLowfluorescentLDLuptake-irradiationSRD-12B胆固醇代谢DeBose-BoydRA,BrownMS,LiWP,NohturfftA,GoldsteinJL,EspenshadePJ.Transport-dependentproteolysisofSREBP:relocationofsite-1proteasefromGolgitoERobviatestheneedforSREBPtransporttoGolgi.Cell.1999Dec23;99(7):703-12.NohturfftA,YabeD,GoldsteinJL,BrownMS,EspenshadePJ.RegulatedstepincholesterolfeedbacklocalizedtobuddingofSCAPfromERmembranes.Cell.2000Aug4;102(3):315-23.SterolRegulatedTransportofSCAP胆固醇代谢PurificationSchemeforSCAP-interactingProteinsYangetal.,Cell(2002)489-500胆固醇代谢TwoInsigs:Insig-1andInsig-2A.SequenceAlignmentB.HydropathyPlotYabeetal.,PNAS(2002)12753-8胆固醇代谢Insig胆固醇代谢九、胆固醇代谢的负反馈调控机制（二）HMGCR降解途径胆固醇代谢FromHeJ.etal.,NEnglJMed,(2005),353:1124-1134.andIMSHealth,MIDAS

药品销售排行榜NameCompanyIndicationSalestoJune07($bn)LipitorPfizerHypercholesterolaemia（高胆固醇血症）13.5NexiumAstraZenecaGastroesophagealreflux（胃食管返流）,gastriculcers（胃溃疡）6.9SeretideGSKAsthma（哮喘）6.7PlavixBristol-MyersSquibbAtheroscleroticevents（动脉粥样硬化症）5.8AranespAmgenAnaemia（贫血症）5.1胆固醇代谢HMG-CoAReductase(HMGCR):theRate-LimitingEnzymeinCholesterolBiosyntheticPathway(HMGCR)胆固醇代谢ProposedModelforINSIG-mediatedRegulationof

HMGCoAReductaseandSCAP胆固醇代谢Sterol-RegulatedDegradationofHMG-CoAReductaseisBlockedbyInhibitorsofthe26SProteasome

胆固醇代谢WorkingHypothesisforSterol-RegulatedDegradationofHMG-CoAReductase胆固醇代谢Sterol-StimulatedUbiquitinaionofHMGCRRequiresInsigSever,Song,Yabe,etal.,JBC,2003胆固醇代谢AminoAcidSequenceoftheHMG-CoAReductase

MembraneDomain胆固醇代谢Lysines89and248areRequiredfortheSterol-RegulatedUbiquitinationandDegradationofHMGCR

胆固醇代谢StrategyforPurifyingtheE3ofHMG-CoAReductase胆固醇代谢E3ActivityCo-immunoprecipitateswithInsig-1inSterol-TreatedCells胆固醇代谢Identificationofgp78andVCPasInsig-1-associatingproteins胆固醇代谢胆固醇代谢MolecularPathwayforSterol-regulatedDegradationofHMGCRSongetal.,MolCell,2005Whatareotherproteinsinvolvedinthispathway?胆固醇代谢IdentificationofUfd1asagp78interactingproteinIP:Endogenousgp78IP:Endogenousgp78Transfect&CoIPIP:Flag-Ufd1ABC胆固醇代谢Ufd1isrequiredfortheubiquitinationofendogenousHMGCR胆固醇代谢Ufd1enhancestheE3activityofgp78invitro胆固醇代谢DualrolesofUfd1:EnhancingE3activityandPromotingdegradationCaoetal.,CellMetab,2007胆固醇代谢十、饮食胆固醇吸收的分子途径胆固醇代谢(HMGCR)DenovoCholesterolSynthesisisaEnergy-ConsumingProcess18

Acetyl-CoACholesterol27

NADPH11

O218

ATP胆固醇代谢CholesterolBiosynthesisandAbsorptioninHuman300-500mgDietaryAbsorptionBiosynthesis600-900mg~1000mgBiliaryre-absorption胆固醇代谢DietaryCholesterolAbsorptionbyIntestinalEnterocytesCholesterolEsterHydrolysisCholesterolCholesterolCholesterolEsterChylomicronIntestinallumenLymphACAT2EREnterocyteTightJunctionEzetimibe2001CholesterolabsorptioninhibitorEzetimibeNPC1L12004IdentificationofNPC1L1胆固醇代谢HumanNiemannPickC1

Like1(NPC1L1)胆固醇代谢NPC1L1mediatesthere-absorptionofcholesterolfrombileApicalHepatocytesBasolateralApical胆固醇代谢NPC1L1recyclesbetweenPMandERCrespondingtocholesterollevelAB胆固醇代谢OverexpressionofNPC1L1increasesfreecholesteroluptake胆固醇代谢KnockingdownofNPC1L1proteininL02cellsattenuatestheuptakeoffreecholesterol胆固醇代谢StructuresofdifferentsterolsSterolAbsorption:<5%plantsterols>50%cholesterol胆固醇代谢Sterol-specificityforNPC1L1-mediatedinternalizationAB胆固醇代谢Hypothesis:NPC1L1med