SUMO化PPARγ1與FOXO1相互作用正反饋調節(jié)高脂高糖應激誘導血管內皮胰島素抵抗

SUMO化PPARγ1與FOXO1相互作用正反饋調節(jié)高脂高糖應激誘導血管內皮胰島素抵抗摘要：胰島素抵抗是糖尿病的主要病理基礎之一，而血管內皮細胞的胰島素抵抗是糖尿病類型2的主要癥狀。本研究利用蛋白質協同作用鑒定技術發(fā)現，SUMO化PPARγ1和FOXO1相互作用，并且它們之間存在正反饋機制，參與高脂高糖應激誘導血管內皮胰島素抵抗的調節(jié)過程。我們通過細胞實驗和小鼠模型研究發(fā)現，SUMO化PPARγ1和FOXO1相互作用可以降低細胞的胰島素信號轉導，抑制葡萄糖攝取，提高血管內皮細胞的脂肪酸吸收和轉運，引起血管內皮細胞的胰島素抵抗和血管損傷。我們還發(fā)現通過抑制SUMO化PPARγ1和FOXO1的相互作用，可以恢復血管內皮細胞的胰島素敏感性，改善高脂高糖誘導的胰島素抵抗和血管內皮損傷。因此，我們的研究揭示了一種新的糖尿病發(fā)病機制，并提供了有前景的靶標和治療策略。

關鍵詞：SUMO化PPARγ1；FOXO1；相互作用；正反饋；胰島素抵抗；血管內皮

Introduction

胰島素抵抗是糖尿病發(fā)展的主要病理生理基礎之一。在糖尿病患者中，胰島素的生物效應減弱或消失，導致高血糖和代謝紊亂。胰島素抵抗不僅是糖尿病的重要病理生理過程，還與多種慢性疾病和肥胖癥等相關。血管內皮細胞是維持心血管功能的重要組成部分，同時也是胰島素信號轉導的主要靶細胞。胰島素通過激活胰島素受體，促進細胞葡萄糖攝取和代謝，同時還能影響脂質代謝和氧化應激等生理過程。糖尿病患者往往存在血管內皮細胞的胰島素抵抗和血管損傷，但其發(fā)生的分子機制仍不清楚。

MaterialsandMethods

本研究利用蛋白質協同作用鑒定技術篩選出SUMO化PPARγ1和FOXO1相互作用。通過Westernblot和熒光共定位實驗驗證它們的相互作用。使用小分子SUMO化酶抑制劑和分子遺傳學方法調控它們的SUMO化水平，檢測胰島素信號通路和脂質代謝的相關分子表達。重建高脂高糖誘導的血管內皮胰島素抵抗模型，比較不同處理組的胰島素敏感性和細胞功能。

Results

本研究發(fā)現SUMO化PPARγ1和FOXO1相互作用，并且存在正反饋機制調節(jié)它們的活性。在高脂高糖應激誘導下，SUMO化PPARγ1和FOXO1相互作用可以降低細胞胰島素信號通路的響應性，抑制葡萄糖攝取，但是促進脂肪酸吸收和轉運。這種改變導致血管內皮細胞的胰島素抵抗和血管損傷。與此相似，抑制SUMO化PPARγ1和FOXO1相互作用可以恢復血管內皮細胞的胰島素敏感性，改善高脂高糖誘導的胰島素抵抗和血管內皮損傷。

Conclusion

SUMO化PPARγ1和FOXO1相互作用通過正反饋機制調節(jié)高脂高糖應激誘導的血管內皮胰島素抵抗。這項研究發(fā)現了一種新的糖尿病發(fā)病機制，提供了靶向調節(jié)SUMO化PPARγ1和FOXO1相互作用的治療策略。這類治療策略有可能用于治療糖尿病和心血管疾病相關的胰島素抵抗和血管損傷。Introduction

Type2diabetesisaworldwidehealthproblemthataffectsindividualsofallages.Itisrelatedtoinsulinresistanceinwhichcellsfailtorespondtoinsulinresultinginelevatedbloodglucoselevels.Insulinresistancehasbeenshowntobeassociatedwithvariousmetabolicdisordersincludingobesity,dyslipidemia,andcardiovasculardisease.Thevascularendotheliumplaysacriticalroleinthedevelopmentofinsulinresistance,andtheunderlyingmechanismsarenotcompletelyunderstood.

Post-translationalmodificationbySUMOylationisareversibleprocessthatregulatesproteinactivity,localization,andinteractions.RecentstudieshavesuggestedthatSUMOylationisinvolvedininsulinsignalingandglucosemetabolism.However,theroleofSUMOylationinvascularendothelium-mediatedinsulinresistanceremainsunclear.

Inthisstudy,weinvestigatedthemolecularmechanismsbywhichSUMOylationregulatesinsulinresistanceinvascularendothelialcells.WefocusedontheinteractionbetweenSUMOylatedPPARγ1andFOXO1,twotranscriptionfactorsknowntoplayimportantrolesininsulinsignalingandglucosemetabolism.

Methods

Weperformedco-immunoprecipitationandimmunofluorescenceassaystoverifytheinteractionbetweenSUMOylatedPPARγ1andFOXO1invascularendothelialcells.WeusedsmallmoleculeinhibitorsofSUMOylationandgeneticmanipulationtomodulatetheirSUMOylationlevelsandevaluatedtheexpressionofmoleculesrelatedtoinsulinsignalingandlipidmetabolism.Wealsoreconstructedahigh-fat-high-glucose-inducedvascularendothelialinsulinresistancemodelandcomparedtheinsulinsensitivityandcellularfunctionofdifferenttreatmentgroups.

Results

WefoundthatSUMOylatedPPARγ1andFOXO1interactedwitheachotherandapositivefeedbackmechanismregulatedtheiractivity.Underhigh-fat-high-glucosestress,theinteractionbetweenSUMOylatedPPARγ1andFOXO1coulddecreasetheresponsivenessofthecellularinsulinsignalingpathway,inhibitglucoseuptake,butpromotefattyacidabsorptionandtransportation.Thesechangescausedinsulinresistanceinvascularendothelialcellsandvasculardamage.Similarly,inhibitingtheinteractionbetweenSUMOylatedPPARγ1andFOXO1couldrestoreinsulinsensitivityinvascularendothelialcellsandimprovehigh-fat-high-glucose-inducedinsulinresistanceandvascularendothelialdamage.

Conclusion

OurstudyrevealedthattheinteractionbetweenSUMOylatedPPARγ1andFOXO1regulatesvascularendothelialinsulinresistanceunderhigh-fat-high-glucosestressthroughapositivefeedbackmechanism.Weidentifiedanovelmechanismunderlyingthedevelopmentoftype2diabetesandprovidedtherapeuticstrategiestargetingtheinteractionbetweenSUMOylatedPPARγ1andFOXO1thatmaybeusedtotreatinsulinresistanceandvasculardamageassociatedwithdiabetesandcardiovasculardiseases。Insummary,theinteractionbetweenSUMOylatedPPARγ1andFOXO1playsacrucialroleinregulatingvascularendothelialinsulinresistanceunderhigh-fat-high-glucosestress.Thisinteractionformsapositivefeedbackmechanism,anddisruptionofthisinteractionmayofferatherapeuticstrategytotreatinsulinresistanceandvasculardamageassociatedwithtype2diabetesandcardiovasculardiseases.

RecentstudieshavealsoshownthattargetingtheinteractionbetweenSUMOylatedPPARγ1andFOXO1maybeapotentialtherapeuticstrategyforotherdiseases.Forexample,SUMOylatedPPARγ1hasbeenfoundtoplayanimportantroleinthedevelopmentofnon-alcoholicfattyliverdisease(NAFLD).TheactivationofPPARγ1byitsligandsleadstotheupregulationoflipogenicgenesandaccumulationoftriglyceridesinhepatocytes,promotingthedevelopmentofNAFLD.However,theinteractionbetweenSUMOylatedPPARγ1andFOXO1caninhibitthelipogenicactivityofPPARγ1,therebyreducingtheaccumulationoftriglyceridesinhepatocytesandamelioratingNAFLD.

Furthermore,theinteractionbetweenSUMOylatedPPARγ1andFOXO1hasalsobeenimplicatedincancerdevelopmentandprogression.PPARγ1isknowntoplayadualroleincancer,actingasatumorsuppressorinsometypesofcancerandasatumorpromoterinothers.TheinteractionbetweenSUMOylatedPPARγ1andFOXO1canmodulatethetranscriptionalactivityofPPARγ1,therebyaffectingitsdualrolesincancer.Targetingthisinteractionmayofferanovelapproachforcancertherapy.

Inconclusion,theinteractionbetweenSUMOylatedPPARγ1andFOXO1isapromisingtargetforthedevelopmentoftherapeuticstrategiesformultiplediseases.Furtherstudiesareneededtofullyelucidatethemechanismsunderlyingtheinteractionbetweentheseproteinsandtoevaluatetheefficacyandsafetyoftargetingthisinteractionfordiseasetreatment。Furthermore,otherpotentialtargetsofPPARγ1SUMOylationandtheirimpactondiseasepathogenesisremaintobeexplored.EmergingevidencesuggeststhatPPARγ1isinvolvedindictatingtheimmuneresponseandmetabolisminvarioustissues.Therefore,targetingPPARγ1SUMOylationmayalsohavepotentialtherapeuticimplicationsformetabolicdisorders,suchasdiabetesandobesity,aswellasautoimmunedisorders.

Moreover,theidentificationofsmallmoleculesthatcanspecificallytargetthePPARγ1-SUMO1-FOXO1interactioncouldprovideanewavenuefordrugdevelopment.ThesemoleculescouldbeusedtomodulatetheinteractionbetweenPPARγ1andFOXO1andinfluencedownstreamsignalingpathways,resultinginpotentialtherapeuticbenefitsforavarietyofdiseases.

However,itshouldbenotedthattheuseofsmallmoleculestotargetprotein-proteininteractionsremainsachallengingtask.Severalapproaches,includingstructural-baseddrugdesignandhigh-throughputscreening,havebeendevelopedtoaddressthesechallenges.Nonetheless,thoroughtestingandvalidationwillberequiredtoensurecompoundspecificityandsafetybeforeclinicalapplication.

Insummary,theemergingroleofPPARγ1SUMOylationindiseasepathogenesissuggeststhattargetingtheinteractionbetweenSUMOylatedPPARγ1andFOXO1mayofferapromisingapproachtocombatdiversediseases,includingcancer,metabolicdisorders,andautoimmunedisorders.Futurestudiesareneededtoelucidatetheprecisemechanismsunderlyingtheseinteractionsandtoidentifyspecificmoleculartargetsfordrugdevelopment。Additionally,theroleofPPARγ1SUMOylationininflammatoryprocessesisalsoanareaofinterest.IthasbeenshownthatinflamedtissueshavedecreasedlevelsofPPARγ1SUMOylation,leadingtoanupregulationofpro-inflammatorygenes.Therefore,targetingtheinteractionbetweenSUMOylatedPPARγ1andFOXO1mayofferapotentialtherapeuticapproachforinflammatorydisorders.

Furthermore,theuseofPPARγ1agonistssuchasthiazolidinediones(TZDs)forthetreatmentofmetabolicdisorderssuchastype2diabeteshasbeenextensivelystudied.However,theuseofTZDshasbeenassociatedwithadverseeffectssuchasweightgainandincreasedriskofheartfailure.Therefore,targetingtheinteractionbetweenSUMOylatedPPARγ1andFOXO1mayprovideanalternativeapproachforthetreatmentofmetabolicdisorderswithouttheunwantedsideeffectsofTZDs.

Inconclusion,theemergingroleofPPARγ1SUMOylationindiseasepathogenesisopensupnewavenuesforthedevelopmentoftargetedtherapies.TargetingtheinteractionbetweenSUMOylatedPPARγ1andFOXO1mayofferpromisingapproachesforthetreatmentofdiversediseasessuchascancer,metabolicdisorders,andautoimmunedisorders.However,furtherstudiesareneededtoelucidatetheprecisemechanismsunderlyingtheseinteractionsandtoidentifyspecificmoleculartargetsfordrugdevelopment。Moreover,recentstudieshavealsohighlightedthepotentialtherapeuticbenefitsofmodulatingPPARγ1activityinneurologicaldisorderssuchasAlzheimer'sdisease(AD)andParkinson'sdisease(PD).PPARγ1hasbeenshowntobeinvolvedinregulatingvariousaspectsofneuroinflammation,oxidativestress,andneuronalsurvival,whichareallkeypathologicalfeaturesoftheseneurodegenerativedisorders.Inparticular,PPARγ1activationhasbeenfoundtohaveneuroprotectiveeffectsinanimalmodelsofADandPD,suggestingthattargetingPPARγ1maybeapromisingstrategyforthedevelopmentofdisease-modifyingtherapiesforthesedevastatingdiseases.

Inaddition,theemergingroleofPPARγ1inregulatingimmunecellfunctionhasalsoattractedattentionasapotentialtherapeutictargetinautoimmunedisorderssuchasmultiplesclerosis(MS)andrheumatoidarthritis(RA).PPARγ1hasbeenshowntomodulatetheactivityofvariousimmunecelltypesincludingTcells,Bcells,andmacrophages,anditsactivationhasbeenfoundtohaveanti-inflammatoryeffectsinanimalmodelsofthesediseases.Therefore,targetingPPARγ1mayprovideanovelapproachforthetreatmentofautoimmunedisordersbyregulatingtheimmuneresponseandreducinginflammation.

Inconclusion,theemergingroleofPPARγ1indiseasepathogenesishighlightsitspotentialasatherapeutictargetfordiversediseases,includingcancer,metabolicdisorders,neurologicaldisorders,andautoimmunedisorders.ThedevelopmentoftargetedtherapiesthatmodulatePPARγ1activityoritsinteractionswithotherkeymolecularplayersmayleadtothedevelopmentofnewdisease-modifyingtreatmentsforthesedebilitatingconditions.However,furtherresearchisneededtofullyunderstandthemechanismsunderlyingPPARγ1'sdiversefunctionsandtoidentifyspecificmoleculartargetsfordrugdevelopment。Inadditiontoitsroleinvariousdiseasepathways,PPARγ1hasalsobeenimplicatedinregulatinglipidmetabolism,insulinsignaling,andinflammation.ThesefunctionshighlightthepotentialimportanceofPPARγ1inthecontextofmetabolicdisorderssuchasdiabetesandobesity.

StudieshaveshownthatPPARγ1activationcanimproveinsulinsensitivityandglucosehomeostasisinanimalmodelsofdiabetes.Furthermore,PPARγ1hasbeenshowntopromotelipidstorageinadipocytes,whichcanhelppreventectopiclipidaccumulationintissuessuchastheliverandmuscle,whichcanleadtoinsulinresistance.

PPARγ1hasalsobeenshowntohaveanti-inflammatoryeffectsinvariouscontexts.Forexample,activationofPPARγ1cansuppresstheproductionofpro-inflammatorycytokinesandchemoki