title: Inhibition of secretion of interleukin (IL)-12/IL-23 family cytokines by 4-trifluoromethyl-celecoxib is coupled to degradation via the endoplasmic reticulum stress protein HERP.
abstract: Interleukin-12 (IL-12), p80, and IL-23 are structurally related cytokines sharing a p40 subunit. We have recently demonstrated that celecoxib and its COX-2-independent analogue 4-trifluoromethyl-celecoxib (TFM-C) inhibit secretion but not transcription of IL-12 (p35/p40) and p80 (p40/p40). This is associated with a mechanism involving altered cytokine-chaperone interaction in the endoplasmic reticulum (ER). In the present study, we found that celecoxib and TFM-C also block secretion of IL-23 (p40/p19 heterodimers). Given the putative ER-centric mode of these compounds, we performed a comprehensive RT-PCR analysis of 23 ER-resident chaperones/foldases and associated co-factors. This revealed that TFM-C induced 1.5-3-fold transcriptional up-regulation of calreticulin, GRP78, GRP94, GRP170, ERp72, ERp57, ERdj4, and ERp29. However, more significantly, a 7-fold up-regulation of homocysteine-inducible ER protein (HERP) was observed. HERP is part of a high molecular mass protein complex involved in ER-associated protein degradation (ERAD). Using co-immunoprecipitation assays, we show that TFM-C induces protein interaction of p80 and IL-23 with HERP. Both HERP siRNA knockdown and HERP overexpression coupled to cycloheximide chase assays revealed that HERP is necessary for degradation of intracellularly retained p80 by TFM-C. Thus, our data suggest that targeting cytokine folding in the ER by small molecule drugs could be therapeutically exploited to alleviate inappropriate inflammation in autoimmune conditions.
authors.affiliation: Neurogenomiks Laboratory, Universidad Del País Vasco (UPV/EHU), Parque Tecnológico de Bizkaia, 48170 Zamudio, Spain.
authors.forename: Martin
authors.initials: M
authors.lastname: McLaughlin
authors.forename: Iraide
authors.initials: I
authors.lastname: Alloza
authors.forename: Hung Pham
authors.initials: HP
authors.lastname: Quoc
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Scott
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Hirabayashi
authors.forename: Koen
authors.initials: K
authors.lastname: Vandenbroeck
mesh_terms: D000818:Animals; D000068579:Celecoxib; D002460:Cell Line; D003513:Cycloheximide / Q000378:metabolism; D052246:Cyclooxygenase 2 Inhibitors / Q000737:chemistry / Q000378:metabolism; D004441:Ecdysterone / Q000031:analogs & derivatives / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D000091342:Endoplasmic Reticulum Chaperone BiP; D005786:Gene Expression Regulation; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D018664:Interleukin-12 / Q000378:metabolism*; D053759:Interleukin-23 / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D011500:Protein Synthesis Inhibitors / Q000378:metabolism; D011720:Pyrazoles / Q000737:chemistry / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D013449:Sulfonamides / Q000737:chemistry / Q000378:metabolism
chemical_list: D052246:Cyclooxygenase 2 Inhibitors; D000091342:Endoplasmic Reticulum Chaperone BiP; C485932:HERPUD1 protein, human; C000717247:HSPA5 protein, human; D006360:Heat-Shock Proteins; D053759:Interleukin-23; D008565:Membrane Proteins; D018832:Molecular Chaperones; D021122:Protein Subunits; D011500:Protein Synthesis Inhibitors; D011720:Pyrazoles; D034741:RNA, Small Interfering; D013449:Sulfonamides; D018664:Interleukin-12; D004441:Ecdysterone; C008999:ponasterone A; D003513:Cycloheximide; D000068579:Celecoxib