Trpa1 Expression Is Downregulated By Dexamethasone And Aurothiomalate In Human Chondrocytes: Trpa1 As A Novel Factor And Drug Target In Arthritis

### Key messages#### What is already known about this subject?#### What does this study add?#### How might this impact on clinical practice?Transient receptor potential ankyrin 1 (TRPA1) is a ligand-gated membrane-bound cation channel. TRPA1 has been largely studied in neurons, where it mediates pain and neurogenic inflammation and acts as a chemosensor for harmful exogenous compounds.1 2 More recently, TRPA1 has been found to be activated also by endogenous compounds formed in inflammatory conditions characteristic to arthritis, such as reactive oxygen and nitrogen species.3We have recently discovered that TRPA1 is functionally expressed in primary human osteoarthritic chondrocytes,4 where it upregulated the production of mediators related to arthritis: interleukin (IL)-6, prostaglandin E2 and matrix metalloproteinases 1, 3 and 13.4 Furthermore, we showed in monosodium iodoacetate-induced experimental arthritis that TRPA1 activation mediates inflammation, cartilage degradation and …