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

• Published in: The Journal of biological chemistry Vol. 285; no. 10; pp. 6960 - 6969
• Main Authors: McLaughlin, Martin, Alloza, Iraide, Quoc, Hung Pham, Scott, Christopher J., Hirabayashi, Yasuhiko, Vandenbroeck, Koen
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 05.03.2010; American Society for Biochemistry and Molecular Biology
• Subjects: Animals; Celecoxib; Cell Line; Chaperone Chaperonin; Cycloheximide - metabolism; Cyclooxygenase 2 Inhibitors - chemistry; Cyclooxygenase 2 Inhibitors - metabolism; Cytokines/Interleukins; Ecdysterone - analogs & derivatives; Ecdysterone - metabolism; Endoplasmic Reticulum (ER); Endoplasmic Reticulum - metabolism; Gene Expression Regulation; Heat-Shock Proteins - genetics; Heat-Shock Proteins - metabolism; HERP; Humans; Interleukin-12 - metabolism; Interleukin-23; Interleukin-23 - metabolism; Membrane Proteins - genetics; Membrane Proteins - metabolism; Molecular Chaperones - genetics; Molecular Chaperones - metabolism; Protein Structure and Folding; Protein Subunits - genetics; Protein Subunits - metabolism; Protein Synthesis Inhibitors - metabolism; Protein/Degradation; Protein/Secretion; Pyrazoles - chemistry; Pyrazoles - metabolism; RNA, Small Interfering - genetics; RNA, Small Interfering - metabolism; Sulfonamides - chemistry; Sulfonamides - metabolism; Protein/Secretion; Chaperone Chaperonin; Interleukin-23; Protein/Degradation; Cytokines/Interleukins; HERP; Celecoxib; Endoplasmic Reticulum (ER)
• ISSN: 0021-9258; 1083-351X; 1083-351X
• DOI: 10.1074/jbc.M109.056614

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.