IDO1 and TGF- 1 β mediate protective effects of IFN-α in antigen-induced arthritis
(English)Manuscript (preprint) (Other academic)
Interferon-α (IFN-α) prevents antigen-induced arthritis (AIA) in mice by an unknown mechanism. Indoleamine 2, 3 dioxygenase 1 (IDO1) is an immunoregulator via enzymatic as well as signalling activity, which can be activated by TGF-β and further mediated via non canonical NF-κB signalling. We here investigated whether IDO1 and TGF-β are involved in IFN-α protective effects in AIA. Arthritis was induced in wt, Ido1-/- or Ifnar-/- mice, treated or not with IFN-α or kynurenine, the main IDO1 product, and antibodies neutralizing TGF-β or 1-methyltryptophan (1-MT), an inhibitor of IDO1 catalytic activity. IDO1 expression and enzymatic activity were determined by RT-PCR and HPLC, respectively. Proliferation was measured by 3H-Thymidine incorporation. Non-canonical NF-κB signalling was evaluated by ELISA and Western blot in plasmacytoid DCs (pDCs) from treated mice. Protective effects of IFN-α in AIA were associated with increased IDO1 expression and kynurenine production in spleen cells, particularly at the time of mBSA sensitization. Lack of IDO1 ablated IFN-α protection and kynurenine prevented AIA in an IFNAR-independent manner. The IDO1 catalytic activity was crucial for IFN-α effects at the sensitization but not effector phase of AIA. The disease effector phase in mice treated with IFN-α was instead characterized by sustained IDO1 and TGF-β expression and activation of the noncanonical NF-κB pathway in pDCs. IFN-α protective effects in AIA involves IDO1 enzymatic and signalling activity in the disease sensitization and effector phase, respectively. Kynurenine, the main IDO1 metabolite, can be used as an alternative treatment to IFN-α in protecting mice from AIA.
Pharmacology and Toxicology Rheumatology and Autoimmunity Clinical Medicine
IdentifiersURN: urn:nbn:se:liu:diva-122461OAI: oai:DiVA.org:liu-122461DiVA: diva2:866546
FunderSwedish Research CouncilSwedish Rheumatism AssociationLinköpings universitet