SUMO化PPARγ1與FOXO1相互作用正反饋調(diào)節(jié)高脂高糖應(yīng)激誘導(dǎo)血管內(nèi)皮胰島素抵抗摘要：胰島素抵抗是糖尿病的主要病理基礎(chǔ)之一，而血管內(nèi)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(zhì)協(xié)同作用鑒定技術(shù)發(fā)現(xiàn)，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(yīng)激誘導(dǎo)血管內(nèi)皮胰島素抵抗的調(diào)節(jié)過程。我們通過細胞實驗和小鼠模型研究發(fā)現(xiàn)，SUMO化PPARγ1和FOXO1相互作用可以降低細胞的胰島素信號轉(zhuǎn)導(dǎo)，抑制葡萄糖攝取，提高血管內(nèi)皮細胞的脂肪酸吸收和轉(zhuǎn)運，引起血管內(nèi)皮細胞的胰島素抵抗和血管損傷。我們還發(fā)現(xiàn)通過抑制SUMO化PPARγ1和FOXO1的相互作用，可以恢復(fù)血管內(nèi)皮細胞的胰島素敏感性，改善高脂高糖誘導(dǎo)的胰島素抵抗和血管內(nèi)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(biāo)和治療策略。

關(guān)鍵詞：SUMO化PPARγ1；FOXO1；相互作用；正反饋；胰島素抵抗；血管內(nèi)皮

Introduction

胰島素抵抗是糖尿病發(fā)展的主要病理生理基礎(chǔ)之一。在糖尿病患者中，胰島素的生物效應(yīng)減弱或消失，導(dǎo)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(guān)。血管內(nèi)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(zhuǎn)導(dǎo)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(zhì)代謝和氧化應(yīng)激等生理過程。糖尿病患者往往存在血管內(nèi)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(zhì)協(xié)同作用鑒定技術(shù)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(xué)方法調(diào)控它們的SUMO化水平，檢測胰島素信號通路和脂質(zhì)代謝的相關(guān)分子表達。重建高脂高糖誘導(dǎo)的血管內(nèi)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(xiàn)SUMO化PPARγ1和FOXO1相互作用，并且存在正反饋機制調(diào)節(jié)它們的活性。在高脂高糖應(yīng)激誘導(dǎo)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(yīng)性，抑制葡萄糖攝取，但是促進脂肪酸吸收和轉(zhuǎn)運。這種改變導(dǎo)致血管內(nèi)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(fù)血管內(nèi)皮細胞的胰島素敏感性，改善高脂高糖誘導(dǎo)的胰島素抵抗和血管內(nèi)皮損傷。

Conclusion

SUMO化PPARγ1和FOXO1相互作用通過正反饋機制調(diào)節(jié)高脂高糖應(yīng)激誘導(dǎo)的血管內(nèi)皮胰島素抵抗。這項研究發(fā)現(xiàn)了一種新的糖尿病發(fā)病機制，提供了靶向調(diào)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(guān)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