to disease pathogenesis its activation, altered expression and in psoriasis maycontribute Keratinocytes functional express CARD18, a negative regulator ofinﬂammasome Molecular Immunology

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MolecularImmunology73(2016)10–18

ContentslistsavailableatScienceDirect

Molecular Immunology

jo u r n al h om ep age:w w w . e l s e v i e r . c o m / l o c a t e / m o l i m m

Keratinocytes express functional CARD18, a negative regulator of inﬂammasome activation, and its altered expression in psoriasis may contribute to disease pathogenesis

Anikó Göblös

^a,∗

, Judit Danis

^a

, Krisztina Vas

^a

, Zsuzsanna Bata-Csörg ˝o

^a,b

, Lajos Kemény

^a,b

, Márta Széll

^b,c

aDepartmentofDermatologyandAllergology,UniversityofSzeged,Korányifasor6,H-6720Szeged,Hungary

bMTA-SZTEDermatologicalResearchGroup,UniversityofSzeged,Korányifasor6,H-6720Szeged,Hungary

cDepartmentofMedicalGenetics,UniversityofSzeged,Somogyiu.4,H-6720Szeged,Hungary

a r t i c l e i n f o

Articlehistory:

Received20January2016

Receivedinrevisedform10March2016 Accepted22March2016

Availableonline26March2016

Keywords:

Psoriasis Inﬂammation Caspase-1 AIM2 IL-1␤

CARD18

a b s t r a c t

Caspaserecruitmentdomainfamilymember18(CARD18,Iceberg)isknownasanegativeregulatory moleculethatinhibitsinﬂammatoryeventsbyterminatinginﬂammasomeactivationduetoadirect interactionwithpro-caspase-1.

Duringtheinvestigationofmolecularmechanismsinkeratinocytesthatcontributetothepathogenesis ofpsoriasis,wefoundthatCARD18expressiondiffersinhealthyandpsoriaticskin;moreover,CARD18 demonstratedalteredresponseunderinflammatoryconditionsinhealthyandpsoriaticskin.Inhealthy skin,lowbasalCARD18expressionwasdetected,whichshowedsignificantelevationinresponseto inflammatorystimuli(lymphokinetreatmentormechanicalinjury).Incontrast,higherbasalexpression wasobservedinpsoriaticnon-involvedskin,butnofurtherinductioncouldbedetected.

WedemonstratedthatkeratinocytesexpressCARD18bothatmRNAandproteinlevelsandtheexpres- sionincreased inparallelwithdifferentiation.Theinvestigationofcellular inflammatoryprocesses revealedthatpsoriasis-associateddangersignalstriggeredtheexpressionofinflammasomecomponents (AIM2,Caspase-1)andCARD18aswellasIL-1␤productionofkeratinocytes.Furthermore,gene-specific silencingofCARD18incellstreatedwithcytosolicDNA(poly(dA:dT))resultedinincreasedIL-1␤secre- tion,suggestinganegativeregulatoryroleforCARD18inkeratinocyteinflammatorysignaling.

ThedifferentialregulationofCARD18inhealthyandpsoriaticuninvolvedepidermismaycontribute tothesusceptibilityofpsoriasis.Furthermore,ourinvitroresultsindicatethatCARD18maycontribute totheﬁnetuningofkeratinocyteinnateimmuneprocesses.

Abbreviations: AIM2,absenceinmelanoma2;CARD18,caspaserecruitment domain family member 18; COP, CARD-only protein; DAPI, 4,6-diamidino- 2-phenylindole;DNase,deoxyribonucleases; GM-CSF,granulocyte macrophage colony-stimulating factor; IL, interleukin; IFN-γ, interferon-γ; TNF, tumor necrosisfactor;IHC, immunohistochemistry;NHEK, normalhuman epidermal keratinocytes; PBS,phosphate-buffered saline; poly(dA:dT), polydeoxyadenylic acid–polydeoxythymidylicaciddouble-strandedhomopolymer;TS,tapestripping.

∗Correspondingauthor.

E-mailaddresses:goblos.aniko@med.u-szeged.hu(A.Göblös),

danis.judit@med.u-szeged.hu(J.Danis),vas.krisztina@med.u-szeged.hu(K.Vas), bata.zsuzsa@med.u-szeged.hu(Z.Bata-Csörg ˝o),kemeny.lajos@med.u-szeged.hu (L.Kemény),szell.marta@med.u-szeged.hu(M.Széll).

1. Introduction

Theinnateimmunesystemconstitutestheﬁrstlineofdefense thatdetectspathogen-anddamage-associatedmolecularpatterns.

Inflammation is a protective physiological response; however, impairedactivationand/ordown-regulationofinflammatorysig- nalingmayresultininflammatorydiseases,someofwhichinvolve multipleorgans.Inflammasomes,locatedinthecytosol,arepart oftheinnateimmunesystem.Thesemulti-molecularcomplexes areresponsible for therecognitionof variouscytoplasmic dan- gersignalsandprovokeinflammatoryresponsesbyrecruitingand activatingpro-caspase-1throughautocatalyticcleavage(Schroder andTschopp,2010).Theactivationofcaspase-1ultimatelyleadsto theprocessingand,thus,secretionofpro-inflammatorycytokines, mostimportantlyinterleukin(IL)1␤andIL-18,andalsoinduces