Deletion of activin A in mesenchymal but not myeloid cells ameliorates disease severity in experimental arthritis

Autor: Vanessa Waltereit-Kracke, Corinna Wehmeyer, Denise Beckmann, Eugenie Werbenko, Julia Reinhardt, Fabienne Geers, Mike Dienstbier, Michelle Fennen, Johanna Intemann, Peter Paruzel, Adelheid Korb-Pap, Thomas Pap, Berno Dankbar
Rok vydání: 2021
Předmět:
Zdroj: Annals of the rheumatic diseases. 81(8)
ISSN: 1468-2060
Popis: ObjectiveThe aim of this study was to assess the extent and the mechanism by which activin A contributes to progressive joint destruction in experimental arthritis and which activin A-expressing cell type is important for disease progression.MethodsLevels of activin A in synovial tissues were evaluated by immunohistochemistry, cell-specific expression and secretion by PCR and ELISA, respectively. Osteoclast (OC) formation was assessed by tartrat-resistant acid phosphatase (TRAP) staining and activity by resorption assay. Quantitative assessment of joint inflammation and bone destruction was performed by histological and micro-CT analysis. Immunoblotting was applied for evaluation of signalling pathways.ResultsIn this study, we demonstrate that fibroblast-like synoviocytes (FLS) are the main producers of activin A in arthritic joints. Most significantly, we show for the first time that deficiency of activin A in arthritic FLS (ActβAd/dColVI-Cre) but not in myeloid cells (ActβAd/dLysM-Cre) reduces OC development in vitro, indicating that activin A promotes osteoclastogenesis in a paracrine manner. Mechanistically, activin A enhanced OC formation and activity by promoting the interaction of activated Smad2 with NFATc1, the key transcription factor of osteoclastogenesis. Consistently, ActβAd/dLysM-Cre hTNFtg mice did not show reduced disease severity, whereas deficiency of activin A in ColVI-Cre-expressing cells such as FLS highly diminished joint destruction reflected by less inflammation and less bone destruction.ConclusionsThe results highly suggest that FLS-derived activin A plays a crucial paracrine role in inflammatory joint destruction and may be a promising target for treating inflammatory disorders associated with OC formation and bone destruction like rheumatoid arthritis.
Databáze: OpenAIRE