title: Suppression of the pro-inflammatory NLRP3/interleukin-1β pathway in macrophages by the thioredoxin reductase inhibitor auranofin.
abstract: BACKGROUND
  The thioredoxin/thioredoxin reductase system, which is best known for its essential role in antioxidant defense and redox homeostasis, is increasingly implicated in the regulation of multiple cellular signaling pathways. In the present study, we asked if the thioredoxin system in macrophages might regulate toll-like receptor 4 (TLR4)-dependent gene expression and consequent responses.
  
  
  METHODS
  Using microarray analysis we analyzed the effect of auranofin, a highly potent and specific inhibitor of thioredoxin reductase, on the transcriptional program activated in J774 macrophages by the TLR4 agonist, lipopolysaccharide (LPS). We used quantitative real-time PCR (qPCR), Western blotting, ELISA and cytotoxicity assays to confirm and extend the microarray results.
  
  
  RESULTS
  Global transcriptional profiling revealed that macrophage treatment with auranofin exerted a selective effect on LPS-induced gene expression, suppressing the induction of a small number of genes. Interestingly, among these suppressed genes were three members of the interleukin-1 (IL-1) family of genes, among which IL-1β was most affected. qPCR analyses confirmed the repressive effects of auranofin on IL-1 genes. In addition, qPCR and Western blot analyses showed that auranofin impaired TLR4-dependent induction of the inflammasome receptor NLRP3, which plays a critical role in IL-1β processing. Consistent with these findings, inflammasome-dependent release of IL-1β from stimulated macrophages was suppressed by auranofin as was inflammasome-mediated cell death.
  
  
  CONCLUSIONS
  Our findings suggest a regulatory role for the thioredoxin system in macrophage inflammatory signaling. Inhibition of the thioredoxin system in macrophages exerts an anti-inflammatory effect by repressing the activation of the NLRP3/IL-1β pathway.
authors: Department of Biochemistry, Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel.
authors: Elina
authors: E
authors: Isakov
authors: Department of Biochemistry, Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel.
authors: Pnina
authors: P
authors: Weisman-Shomer
authors: Department of Biochemistry, Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel. Electronic address: benhar@tx.technion.ac.il.
authors: Moran
authors: M
authors: Benhar
mesh_terms: D000818:Animals; D018501:Antirheumatic Agents / Q000494:pharmacology*; D001310:Auranofin / Q000494:pharmacology*; D002352:Carrier Proteins / Q000378:metabolism*; D002460:Cell Line; D005786:Gene Expression Regulation / Q000187:drug effects; D058847:Inflammasomes / Q000378:metabolism; D053583:Interleukin-1beta / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology; D017737:Macrophages, Peritoneal / Q000378:metabolism*; D051379:Mice; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; D015398:Signal Transduction / Q000187:drug effects*; D013880:Thioredoxin-Disulfide Reductase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000819:agonists / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D018501:Antirheumatic Agents; D002352:Carrier Proteins; D058847:Inflammasomes; D053583:Interleukin-1beta; D008070:Lipopolysaccharides; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; C492716:Nlrp3 protein, mouse; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D001310:Auranofin; D013880:Thioredoxin-Disulfide Reductase
keywords: Inflammation; Interleukin-1β; Macrophage; NLRP3; Thioredoxin reductase; Toll-like receptor