膽固醇代謝課件

膽固醇代謝平衡調(diào)控膽固醇代謝提綱膽固醇的生物學功能膽固醇相關疾病膽固醇的生物合成膽固醇在血液中的運輸家族型高膽固醇血癥NPC疾病膽固醇的降解與清除膽固醇代謝的負反饋調(diào)控機制—SCAP-SREBP途徑膽固醇代謝的負反饋調(diào)控機制—HMGCR降解途徑飲食膽固醇吸收的分子途徑膽固醇代謝Cholesterol（膽固醇）膽固醇代謝一、膽固醇的生物學功能MembraneFluidityBileAcidsHormones、VitaminDSynapseHedgehogModificationSignalTransduction……膽固醇代謝哺乳動物細胞模式圖膽固醇代謝膜上的微結(jié)構(gòu)域膽固醇代謝Cholesterolandcholesterolderivatives

雌激素雄激素膽固醇代謝膽固醇代謝脂肪酸、糖等提供能量（ATP）膽固醇并不提供能量膽固醇代謝二、膽固醇相關疾病膽固醇代謝Cholesterolisthemajorcauseofatherosclerosis膽固醇代謝心腦血管疾病惡性腫瘤肺炎、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腎病其它43.8%22.3%FromHeJ.etal.,NEnglJMed,(2005),353:1124-1134.中國死亡原因統(tǒng)計膽固醇代謝蒙娜麗莎患有高膽固醇？意大利帕勒莫大學的病理解剖學教授弗蘭克，研究認為蒙娜麗莎飲食不健康，患有高膽固醇癥。正是眼部的脂肪瘤，造成了蒙娜麗莎這副神秘莫測的表情。畫中的她（或者說達芬奇的這個模特）正在為自己體內(nèi)過高的膽固醇而擔憂。膽固醇代謝膽結(jié)石老年癡呆癥CholesterolandDiseasesNiemann-PickTypeCDisease糖尿病/肥胖癥膽固醇代謝FromIMSHealth,MIDAS

藥品銷售排行榜NameCompanyIndicationSalestoJune07($bn)LipitorPfizerHypercholesterolaemia（高膽固醇血癥）13.5NexiumAstraZenecaGastroesophagealreflux（胃食管返流）,gastriculcers（胃潰瘍）6.9SeretideGSKAsthma（哮喘）6.7PlavixBristol-MyersSquibbAtheroscleroticevents（動脈粥樣硬化癥）5.8AranespAmgenAnaemia（貧血癥）5.1膽固醇代謝三、膽固醇的生物合成膽固醇代謝CholesterolisnotrequiredinthedietCholesterolisanessentialmoleculebutisnotrequiredinthedietbecauseallcellscansynthesizeitfromsimpleprecursors膽固醇代謝Cholesterolismadefromacetyl-CoAinfourstagesallofitscarbonatomsareprovidedbyasingleprecursor–acetate膽固醇代謝Stage1Threeacetateunitscondensetoformasixcarbonintermediate,mevalonate膽固醇代謝Twomoleculesofacetate-CoAcondenseformingacetoacetyl-CoA.Acetoacetyl-CoAcondenseswithacetyl-CoAtoyieldb-hydroxy-b-methylglutaryl-CoA(HMG-CoA)膽固醇代謝ThefinalstepthereductionofHMG-CoAtomevalonate,catalyzedbyHMG-CoAreductase.膽固醇代謝Stage2ConversionofmevalonateintoactivatedisopreneunitsIsoprenecontainingmoleculesareimportantintermediatesincholesterolbiosynthesis膽固醇代謝Stage3Polymerizationofsix5-carbonisopreneunitstoformthe30-carbonlinearstructureofsqualene.膽固醇代謝Cyclizationofsqualeneformsthefourringsofthesteroidnucleus.Subsequentmodificationsleadstothefinalproduct,cholesterol.Stage4膽固醇代謝膽固醇代謝MostofthecholesterolmadeintheliverisexportedMuchofcholesterolsynthesistakesplaceinthe

liverMostisexported膽固醇代謝Cholesterolisexportedinthreeforms1.Bilesalts–amphipathiccholesterolderivativesthataidlipiddigestion2.Cholesterol–tobile3.Cholesterylesters–transportedandsecretedin lipoproteinparticlestoother tissuesthatusecholesterol orarestoredintheliver膽固醇代謝四、膽固醇在血液中的運輸膽固醇代謝CholesterylesterformationFormedintheliverConvertingcholesteroltoamorehydrophobicform膽固醇代謝Cholesteroltransport:theproblemCholesterolandcholesterylestersareessentiallyinsolubleinwaterThesemoleculesmustbemovedfromthetissueoforigintothetissuesinwhichtheyarestoredorareconsumed膽固醇代謝Cholesteroltransport:thesolutionCholesterolandcholesterylestersarecarriedinthebloodplasmafromonetissuetoanotherasplasmalipoproteins膽固醇代謝Cholesterolestersentercellsby

receptormediatedendocytosis膽固醇代謝五、家族型高膽固醇血癥LDLreceptor(LDLR)突變膽固醇代謝家族性高膽固醇血癥(FamilialHypercholesterolemia,FH)雜合子患者血清總膽固醇較正常人高出1～2倍純合子患者血清總膽固醇較正常人高出6～8倍雜合子患者發(fā)生率為1/500純合子患者發(fā)生率為1/1,000,000雜合子患者男性30～40歲時，患CAD，23%患者在50歲以前死于CAD，>50%患者在60歲時明顯的CAD癥狀；純合子患者十幾歲時，有嚴重的心血管事件甚至死亡膽固醇代謝LDLR突變----黃色瘤膽固醇代謝FH患者LDLR突變----眼底脂質(zhì)滲出正常人膽固醇代謝六、

Niemann-PicktypeC(NPC)疾病溶酶體堆積型疾?。↙ysosomalStorageDisorders）膽固醇在溶酶體中堆積進行性神經(jīng)細胞死亡、肝脾腫大、小腦共濟失調(diào)、癡呆、語言吞咽困難、青春期之前死亡1：120，000發(fā)病，攜帶者1：100NPC1（大的膜蛋白）或NPC2（小的可溶蛋白）基因突變臨床嘗試用環(huán)化糊精進行治療膽固醇代謝正常細胞NPC1突變細胞膽固醇代謝膽固醇代謝膽固醇代謝七、膽固醇的降解與清除膽固醇代謝DegradationofcholesterolTheringstructureofcholesterolcannotbemetabolizedtoCO2andH2OinhumansTheintactsterolringiseliminatedfromthebodyby:Conversiontobileacids,whichareexcretedinfecesSecretionofcholesterolintothebile,whichtransportsittotheintestineforelimination膽固醇代謝SteroidhormonesareformedfromcholesterolAllsteroidhormonesarederivedformcholesterolInthecortexofadrenalglandstwoclassesofhormonesaresynthesized–mineralocorticoidsandglucocorticoidsInthemaleandfemalegonads–sexhormonesareproducedSexhormonesinclude–progesterone,androgensandestrogens膽固醇代謝八、膽固醇代謝的負反饋調(diào)控機制（一）SCAP-SREBP途徑膽固醇代謝膽固醇代謝脂質(zhì)代謝的關鍵蛋白質(zhì)及其功能調(diào)控的臨床意義LDLReceptorsLDLHMGCRSREBPPathwayHMGCRinhibitor膽固醇代謝Insig膽固醇代謝SREBP—膜結(jié)合的轉(zhuǎn)錄因子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.膽固醇代謝膽固醇代謝25-Hydroxycholesterol-irradiationMutantcellssurvive(25-RA)膽固醇代謝AmphotericinB-irradiationCholesterolauxotrophs(M19)HumanfibroblasmgenomicDNAtoM19cellsHfT1M19(c)Growinlipid-deficientmediumGrowinlipid-deficientmediumHfT1M19(c)genomicDNAtoM19cellsHfT2M19(c)Growinlipid-deficientmediumHfT2M19(c)genomicDNAtoM19cellsHfT3M19(c)Inter-AluPCR,usethisprobetoscreengenomicPAClibrary,transfectPACcloneintoM19,sequencePACcloneandcomparewithEST.膽固醇代謝S2PcDNAtoCHOcellsBrieflyincubatedwithLDL,AmphotericinBselection-irradiationLowfluorescentLDLuptake-irradiationSRD-12B膽固醇代謝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膽固醇代謝PurificationSchemeforSCAP-interactingProteinsYangetal.,Cell(2002)489-500膽固醇代謝TwoInsigs:Insig-1andInsig-2A.SequenceAlignmentB.HydropathyPlotYabeetal.,PNAS(2002)12753-8膽固醇代謝Insig膽固醇代謝九、膽固醇代謝的負反饋調(diào)控機制（二）HMGCR降解途徑膽固醇代謝FromHeJ.etal.,NEnglJMed,(2005),353:1124-1134.andIMSHealth,MIDAS

藥品銷售排行榜NameCompanyIndicationSalestoJune07($bn)LipitorPfizerHypercholesterolaemia（高膽固醇血癥）13.5NexiumAstraZenecaGastroesophagealreflux（胃食管返流）,gastriculcers（胃潰瘍）6.9SeretideGSKAsthma（哮喘）6.7PlavixBristol-MyersSquibbAtheroscleroticevents（動脈粥樣硬化癥）5.8AranespAmgenAnaemia（貧血癥）5.1膽固醇代謝HMG-CoAReductase(HMGCR):theRate-LimitingEnzymeinCholesterolBiosyntheticPathway(HMGCR)膽固醇代謝ProposedModelforINSIG-mediatedRegulationof

HMGCoAReductaseandSCAP膽固醇代謝Sterol-RegulatedDegradationofHMG-CoAReductaseisBlockedbyInhibitorsofthe26SProteasome

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

MembraneDomain膽固醇代謝Lysines89and248areRequiredfortheSterol-RegulatedUbiquitinationandDegradationofHMGCR

膽固醇代謝StrategyforPurifyingtheE3ofHMG-CoAReductase膽固醇代謝E3ActivityCo-immunoprecipitateswithInsig-1inSterol-TreatedCells膽固醇代謝Identificationofgp78andVCPasInsig-1-associatingproteins膽固醇代謝膽固醇代謝MolecularPathwayforSterol-regulatedDegradationofHMGCRSongetal.,MolCell,2005Whatareotherproteinsinvolvedinthispathway?膽固醇代謝IdentificationofUfd1asagp78interactingproteinIP:Endogenousgp78IP:Endogenousgp78Transfect&CoIPIP:Flag-Ufd1ABC膽固醇代謝Ufd1isrequiredfortheubiquitinationofendogenousHMGCR膽固醇代謝Ufd1enhancestheE3activityofgp78invitro膽固醇代謝DualrolesofUfd1:EnhancingE3activityandPromotingdegradationCaoetal.,CellMetab,2007膽固醇代謝十、飲食膽固醇吸收的分子途徑膽固醇代謝(HMGCR)DenovoCholesterolSynthesisisaEnergy-ConsumingProcess18

Acetyl-CoACholesterol27

NADPH11

O218

ATP膽固醇代謝CholesterolBiosynthesisandAbsorptioninHuman300-500mgDietaryAbsorptionBiosynthesis600-900mg~1000mgBiliaryre-absorption膽固醇代謝DietaryCholesterolAbsorptionbyIntestinalEnterocytesCholesterolEsterHydrolysisCholesterolCholesterolCholesterolEsterChylomicronIntestinallumenLymphACAT2EREnterocyteTightJunctionEzetimibe2001CholesterolabsorptioninhibitorEzetimibeNPC1L12004IdentificationofNPC1L1膽固醇代謝HumanNiemannPickC1

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