Page - 103 - in Advances in Neuroimmunology

BrainSci. 2017,7, 14 interleukin-1 beta (IL-1β) [2–4]; and induces atrophy of immune organs, such as the spleen and thymus[5–9]. Morphine-inducedimmunosuppressionsignificantly increases theriskofbacterial infection[10]. Although the immunosuppressiveeffectsofmorphinehavebeenwidely studied, themechanisms involved in thebody’s inflammatoryresponse topathogensduringmorphine tolerancehavenotbeen fully investigated. Inflammasomesaremulti-proteincomplexesassembledfromnucleotideoligomerizationdomain receptor proteins known as nucleotide-binding oligomerization domain (NOD)-like receptors (NLR) [11]. They functionas importantmediatorsof innate immunity. Inflammasomesplayakey role in the regulation of inflammation and immune responses byparticipating in the production of pro-inflammatory cytokines, including IL-1β and interleukin-18 (IL-18) [11–13]. Both IL-1β and IL-18 produce a wide variety of biological effects associated with infection, inflammation, andautoimmuneprocesses. There have been about 20NLR inflammasomes identified in humans. Themost commonly studied ones includeNLR Family Pyrin Domain Containing 1 (NLPR1), NLR family apoptosis inhibitoryprotein6 (NAIP2),NLRFamilyPyrinDomainContaining3(NLRP3),NLRFamilyPyrin DomainContaining5(NLRP5),NLRFamilyPyrinDomainContaining6(NLRP6),NLRFamilyPyrin DomainContaining12(NLRP12),NLRfamilymemberX1(NLRPX1),andNLRFamilyCARDDomain Containing4(NLRC4)[14]. Inflammasomeshavebeensub-dividedintotwogroups;pro-inflammatory inflammasomes and anti-inflammatory inflammasomes. The pro-inflammatory inflammasomes includeNLRP3andNLRC4,andtheir functionshavebeenwidelystudied. Theanti-inflammatory inflammasomes includeNLRP12,NLRX1,NLRC3,andNLRC5.Theyappear to functionbylimiting orsuppressingapro-inflammatoryresponse;however, thisgrouphasnotbeenwell studiedtodate. There have been a few recent reports characterizing the anti-inflammatory properties of NLRP12[15,16].NLRP12caninhibitNF-κBsignalingthroughboththecanonicalandnon-canonical pathways,which are important in the control and regulation of innate immune responses [15,16]. NLRP12 inhibits IL-1 receptor-associatedkinase1 (IRAK1),adownstreamcomponentof thepathogen activatedToll-like receptor (TLR)pathway,which, in turn,decreases thesignalingof thecanonical NF-κB pathway [17]. In the non-canonical NF-κB pathway, NLRP12 interacts with and rapidly degradesNF-κB-inducingkinase (NIK), therebysuppressingNF-κBsignaling[18]. TheLibraryof IntegratedNetwork-BasedCellularSignatures (LINCS) [19] isadatabasewhich implementsabiologicalnetwork-basedstrategytomakeassessmentsregardingthe impactofdrugs, genetics, andrelatedbiologicalperturbations (alterations inducedbyexternalor internalmechanisms) on cellular states. The librarydatabase is basedon thephilosophy that typical humanpathology, biology, and pharmacology aremost aptly understood using a systems-level approach. It was constructedtogeneratearobustapproachforperturbingadiversityofcell types,measuringcellular responses, integratingandanalyzingdata,andvisualizingandinterrogating thedatabase foravariety ofbiomedical researchapplications [19]. This libraryallowsresearchers toaccessawidevarietyof databyusingamatrixconsistingofcell typebyexperimental treatmentbyphenotypicassay.Using LINCS, researchersareable to inquireabout informationregardingmechanism-basedrelationships amongtheeffectsofdifferentdrugresponsesandtheir targets (perturbents)aswellasassociations amongrespondingcellularcomponents, in the formatofnetwork interactionsandstructure-function relationships [20]. In thisstudy,weusedaninflammasomePCRarraycontaining84 inflammasome-relatedgenes to investigate the expressionof inflammasomesduring an inflammatory response to thebacterial endotoxin, lipopolysaccharide (LPS), in the ratbrainduringmorphine tolerance. LINCSwas then usedtoprojectpossiblecandidate targets fromthemRNAgeneexpressionprofilesgeneratedfromthe PCRarrayanalysis. 103