T-5224-d8 is the deuterium-labeled form of T-5224. T-5224 acts as a selective inhibitor of the transcription factor c-Fos/activator protein (AP)-1, demonstrating anti-inflammatory properties. It specifically inhibits the DNA binding activity of c-Fos/c-Jun without affecting the binding activity of other transcription factors. T-5224 also suppresses the transcriptional upregulation of IL-1β-induced Mmp-3, Mmp-13, and Adamts-5.