Investigating the role of SMOX in rheumatoid arthritis.

Rheumatoid arthritis (RA) is pathologically marked by joint inflammation and damage. Although the association between spermidine and RA has been recognized, the precise contribution of spermine oxidase (SMOX)-the enzyme catalyzing spermidine synthesis-to RA pathogenesis remains undefined. It's observed in this study that SMOX was responsible for inflammatory stimuli that its expression increased obviously when RA-associated fibroblast-like synoviocytes (FLSs) were challenged by inflammatory factors. Functionally, silencing SMOX could inhibit migration, invasion, and cytokine production, but induced apoptosis of RA-FLS. Moreover, inhibition of SMOX using JNJ-9350 yielded anti-inflammatory effects comparable to those achieved by gene silencing in RA-FLS. In vivo experiments demonstrated that JNJ-9350 could effectively reduce the severity of arthritis, minimize histopathological damage, and prevent bone erosion in collagen antibody-induced arthritis (CAIA) mice. The present results indicate that SMOX is implicated in the development of RA and suggest that targeting SMOX could be a novel treatment strategy.