《Nuclear-receptors(核受体))培训课件》由会员分享，可在线阅读，更多相关《Nuclear-receptors(核受体))培训课件（73页珍藏版）》请在金锄头文库上搜索。
1、INTRACELLULARRECEPTORS Theintracellular nuclear receptorsuperfamilySteroidhormones thyroidhormones retinoidsandvitaminD Regulationoftranscriptionactivity RegulatorymechanismsvaryHeterodimericreceptors exclusivelynuclear withoutligand represstranscriptionbybindingtotheircognatesitesinDNAHomodimericre
2、ceptors mostlycytoplasmic withoutligands hormonebindingleadstonucleartranslocationofreceptorsWithoutligand aggregationofreceptorwithinhibitorproteins egHsp90 SteroidhormonesareoftenrequiredtodimerizewithapartnertoactivategenetranscriptionReceptorsforvitaminD retinoicacidandthyroidhormonebindtorespon
3、siveelementsasheterodimersSecondcomponentoftheheterodimerisRXRmonomer i e RXR RAR RXR VDR Specificitiesofsomereceptors Intracellularsignalmoleculessmall lipid solublemoleculessuchassteroidhormones retinoids thyroidhormones VitaminD madefromcholesterol Thesemoleculesdiffusethroughplasmaandnuclearmemb
4、ranesandinteractdirectlywiththetranscriptionfactorstheycontrol 6 LipophilicHormones CirculationinthebloodboundtotransportproteinsDissociationfromcarrierattargetcellsActioninthecell Passthroughthecellmembraneandbindtoanintracellularreceptor eitherinthecytoplasmorthenucleus Hormone receptorcomplexbind
5、stohormoneresponseelementsinDNA Regulategeneexpression 7 SteroidHormones STEROIDHORMONES sexsteroids estrogen progesterone testosterone corticosteroids glucocorticoidsandmineralcorticoids OTHERHORMONESThyroidhormone vitaminD3 andretinoicacidhavedifferentstructureandfunctionbutsharethesamemechanismof
6、actionwiththeothersteroids BIOSYNTHESISOFSTEROIDS Endocrinedisruption InterferenceofxenobioticswithnormalfunctionofhormonalsystemPossibleconsequences Disruptionofhomeostasis reproduction development and orbehavior andotherhormone controlledprocesses Shiftinsexratio defectivesexualdevelopmentLowfecun
7、dity fertilityHypo immunity carcinogenesisMalformations Toxicantsinteractwithhormonalsystematdifferentlevels Transport Metabolization Interactionwithreceptors Stimulation Suppression biosynthesisandreleaseofhormones bindingtoplasmatictransportproteins bindingtonuclearhormonalreceptor HR activationof
8、HR dissociationofassociatedheatshockproteins formationofhomodimers bindingoftheactivatedreceptorcomplextospecificDNAmotifs HREs chromatinrearrangementandtranscriptionofestrogen induciblegenes effectsatthecellular tissue organ organism and orpopulationlevel e g modulationofCYP11Aand orCYP19activities
9、 e g down regulationofreceptorlevels e g modulationofothernuclearreceptors PPAR RXR RXR TR STEROIDOGENESIS Mechanismsofsteroidhormonessignallingdisruption Nonphysiologicalactivationofhormonereceptor HR BindingtoHRwithoutactivationDecreaseofHRcellularlevelsDisruptionofthe master hormones FSH LH Chang
10、esinhormonemetabolism Endocrinedisruptersintheenvironment EDCs PersistentOrganicCompounds POPsandtheirmetabolites steroidhormonesandtheirderivativesfromcontraceptionpillsalkylphenolsorganometallics butyltins pharmaceuticalsPesticides numberofunknowns ESTROGENRECEPTOR ERthemoststudiedtargetofEDCs Est
11、rogens playakeyroleinfemalehormoneregulationandsignallingareresponsibleformetabolic behaviouralandmorphologicchangesoccurringduringstagesofreproductionareinvolvedinthegrowth developmentandhomeostasisofanumberoftissuescontroltheboneformation regulationofhomeostasis cardiovascularsystemandbehaviourreg
12、ulateproduction transportandconcentrationoftesticularliquidandanabolicactivityofandrogensinmalesSynthesisinovariesDISRUPTION investigatedinaquaticbiota laboratoryorganisms seenotesonEDCs ESTROGENRECEPTORS ER ER subtype ER inbreast ovary brain liver boneandcardiovascularsystem adrenals testisanduroge
13、nitaltract ER inkidneys prostateandgastrointestinaltract ER infish Naturalproductsgenisteinnaringenincoumestrolzearalenone EnvironmentalpollutantDDTkeponePCBs OH PCBsPAHsanddioxins IndustrialchemicalsBisphenolANonionicsurfactantsPthalateestersendosulfan PharmaceuticalsEthinylestradiolDiethylstilbest
14、rolgestodenenorgestrel DEHP Environmentalestrogens xenoestrogens exoestrogens adiversegroupofsubstancesthatdonotnecessarilysharestructuralsimilaritytotheprototypicalestrogen 17 estradiol MayactasAGONISTSand orANTAGONISTS Exoestrogens RelativePotenciestobindtoERa REPs Toxicityassessmentnumberofinvivo
15、andinvitromethods Jano ek J Hilscherov K Bl ha L andHoloubek I 2006 Environmentalxenobioticsandnuclearreceptors Interactions effectsandinvitroassessment ToxicologyinVitro20 18 37 Invitroassays INTERACTION BINDING tothereceptorcompetitiveligandbindingassayEffectunknown Activation suppression noeffect
16、 Testingtheeffectatcellularlevel interferencewithreceptorbiologicalactivity cellproliferationassayendogenousproteinexpression orenzymeactivity assayreportergeneassay InvitroER mediatedeffectsluciferasereporterassay ER mediatedeffectsluciferasereporterassay 96microwellplatecultivationoftransgeniccelllinesER breastcarcinomaMVLNcellsSIMILARDESIGNFOROTHERRECEPTORS discussedbelow AhR H4IIE luccells AR MDAcells RAR RXR P19cells Celllysis extractionofinducedluciferase Exposure 6 24h standards samples L
