Adiponectin 导致的内皮细胞的硝酸氧化物Synthase 活化作用和硝酸氧化物生产由APP

Adiponectin-InducedEndothelialNitricOxideSynthaseActivationandNitricOxideProductionAreMediatedbyAPPL1inEndothelialCellsKennethK.Y.Cheng1,2,KarenS.L.Lam1,2,YuWang3,YuHuang4,DavidCarling5,DonghaiWu6,ChiwaiWong6,andAiminXu1,2,61DepartmentofMedicine,UniversityofHongKong,HongKong,China2ResearchCenterofHeart,BrainHormoneandHealthyAging,UniversityofHongKong,HongKong,China3GenomeResearchCenterandDepartmentofBiochemistry,UniversityofHongKong,HongKong,China4DepartmentofPhysiology,ChineseUniversityofHongKong,HongKong,China5CellularStressGroup,MedicalResearchCouncil(MRC)ClinicalSciencesCentre,ImperialCollege,U.K6GuangzhouInstituteofBiomedicineandHealth,ChineseAcademyofSciences,Guangzhou,ChinaAddresscorrespondenceandreprintrequeststoAiminXu,PhD,DepartmentofMedicine,UniversityofHongKong,L8-43,NewLaboratoryBlock,21SassoonRoad,HongKong.E-mail:[e-mail]:AMPK,AMP-activatedproteinkinase;eNOS,endothelialnitricoxidesynthase;GFP,greenfluorescentprotein;HSP,heatshockprotein;HUVEC,humanumbilicalveinendothelialcell;L-NAME,N-nitro-L-argininemethylester;PI,phosphoinositide;RNAi,RNAinterferenceABSTRACTTOPABSTRACTRESEARCHDESIGNANDMETHODSRESULTSDISCUSSIONREFERENCESAdiponectinprotectsthevascularsystempartlythroughstimulationofendothelialnitricoxide(NO)productionandendothelium-dependentvasodilation.Thecurrentstudyinvestigatedtheroleoftworecentlyidentifiedadiponectinreceptors,AdipoR1and-R2,andtheirdownstreameffectorsinmediatingtheendotheliumactionsofadiponectin.Inhumanumbilicalveinendothelialcells,adiponectin-inducedphosphorylationofendothelialNOsynthase(eNOS)atSer1177andNOproductionwereabrogatedwhenexpressionofAdipoR1and-R2weresimultaneouslysuppressed.ProteomicanalysisdemonstratedthatthecytoplasmictailsofbothAdipoR1and-R2interactedwithAPPL1,anadaptorproteinthatcontainsaPH(pleckstrinhomology)domain,aPTB(phosphotyrosine-binding)domain,andaLeucinezippermotif.SuppressionofAPPL1expressionbyRNAinterferencesignificantlyattenuatedadiponectin-inducedphosphorylationofAMP-activatedproteinkinase(AMPK)atThr172andeNOSatSer1177,andthecomplexformationbetweeneNOSandheatshockprotein90,resultinginamarkedreductionofNOproduction.Adenovirus-mediatedoverexpressionofaconstitutivelyactiveversionofAMPKreversedthesechanges.Indb/dbdiabeticmice,bothAPPL1expressionandadiponectin-inducedvasodilationweresignificantlydecreasedcomparedwiththeirleanlittermates.Takentogether,theseresultssuggestthatAPPL1actsasacommondownstreameffectorofAdipoR1and-R2,mediatingadiponectin-evokedendothelialNOproductionandendothelium-dependentvasodilation.Endothelialdysfunction,characterizedbydecreasedproductionand/orbioactivityofnitricoxide(NO)andimpairedendothelium-dependentvasodilation,isakeymediatorthatlinksobesity,diabetes,andcardiovasculardiseases(1).Dysfunctionoftheendotheliuminconduitarteriesisawell-establishedantecedentofhypertensionandatherosclerosis,whereasdysfunctionofperipheralvascularendotheliumatthearteriolarandcapillarylevelcontributestothepathogenesisofinsulinresistanceandthemetabolicsyndrome(2).Ontheotherhand,insulinresistanceaggravatesendothelialdysfunction.Therapeuticinterventionsinanimalmodelsandhumanshavedemonstratedthatimprovingendothelialfunctionamelioratesinsulinresistance,whileincreasinginsulinsensitivityalleviatesendothelialdysfunction(3).Adiponectin,aninsulin-sensitizingadipokinesecretedpredominantlyfromadipocytes,possessespotentprotectiveeffectsagainstendothelialdysfunction(4).Unlikemostadipokines,plasmalevelsofadiponectinaredecreasedinobeseindividualsandpatientswithinsulinresistance,type2diabetes,andcardiovasculardiseases.Anindependentassociationbetweenserumlevelsofadiponectinandendothelium-dependentvasodilationhasbeenrepeatedlydocumented(5–7).Hypoadiponectinemiahasbeencloselylinkedtoimpairmentinendothelium-dependentvasodilationinbothnormalsubjectsandpatientswithhypertensionandtype2diabetes.Consistentwiththeseclinicalfindings,adiponectin-deficientmiceexhibitreducedendothelium-dependentvasodilationonanatherogenicdiet(6),increasedneointimalhyperplasiaafteracutevascularinjury(8,9),andelevatedbloodpressurecomparedwiththeirwild-typelittermates(10).Ontheotherhand,bothadenovirus-mediatedoverexpressionoffull-lengthadiponectinandtransgenicoverexpressionofglobularadiponectinresultinamarkedalleviationofatheroscleroticlesioninapolipoproteinE–deficientmice(11)andalsocauseasignificantameliorationofendothelialdysfunctionandhypertension(10)inobesemice.Theendothelium-protectivefunctionsofadiponectinaremediated,atleastinpart,byitsabilitytoincreasetheproductionofNO,avasodilatorsynthesizedbyendothelialNOsynthase(eNOS)fromtheprecursorL-arginine(4,7,12).NOprotectsthevascularsystembyenhancingvasodilationandinhibitingplateletaggregation,monocyteadhesion,andsmoothmusclecellproliferation(13).RecentstudiesfromseveralindependentlaboratorieshavedemonstratedthatadiponectinstimulatesendothelialNOproductionandaugmentsendothelium-dependentvasodilation(7,12,14–16).Inendothelialcells,adiponectinenhanceseNOSactivitybyinducingeNOSphosphorylationatSer1177andthecomplexformationbetwee