Extracellular Collagen Promotes Interleukin-1?2a€“Induced Urokinase-Type Plasminogen Activator Production by Human Corneal FibroblastsCollagen Promotes IL-1?2-Induced uPA Production

摘要

Purpose:Keratocytesmaintainhomeostasisofthecornealstromathroughsynthesis,secretion,anddegradationofcollagenfibrilsoftheextracellularmatrix.Giventhatthesecellsareessentiallyembeddedinacollagenmatrix,keratocytea€“collageninteractionsmayplayakeyroleinregulationoftheexpressionoractivationofenzymesresponsibleformatrixdegradationincludingurokinase-typeplasminogenactivator(uPA),plasmin,andmatrixmetalloproteinases(MMPs).WeexaminedtheeffectofextracellularcollagenontheproductionofuPAbycornealfibroblasts(activatedkeratocytes)stimulatedwiththeproinflammatorycytokineinterleukin-1?2(IL-1?2).Methods:Humancornealfibroblastswereculturedeitheronplasticorinathree-dimensionalgeloftypeIcollagen.Plasminogenactivatorsweredetectedbyfibrinzymography,whereastheIL-1receptor(IL-1R)andMMPsweredetectedbyimmunoblotanalysis.Collagendegradationbycornealfibroblastswasassessedbymeasurementofhydroxyprolineinacidhydrolysatesofculturesupernatants.Results:CollagenandIL-1?2synergisticallyincreasedthesynthesisandsecretionofuPAincornealfibroblasts.CollagenalsoupregulatedIL-1Rexpressioninthecellsinaconcentration-dependentmanner.Theconversionofextracellularplasminogentoplasmin,aswellastheplasminogen-dependentactivationofMMP-1andMMP-3anddegradationofcollagenapparentinthree-dimensionalculturesofcornealfibroblastsexposedtoIL-1?2,wereallabolishedbyaselectiveuPAinhibitor.Conclusions:CollagenandIL-1?2cooperatetoupregulateuPAproductionbycornealfibroblasts.Furthermore,IL-1?2a€“inducedcollagendegradationbythesecellsappearstobestrictlydependentonuPAexpressionandmediatedbyauPAa€“plasmina€“MMPpathway.