Endogenous Galectin-9 Suppresses Apoptosis in Human Rheumatoid Arthritis Synovial Fibroblasts.
Mark J PearsonMagdalena A BikCaroline OspeltAmy J NaylorCorinna WehmeyerSimon W JonesChristopher Dominic BuckleySteffen GayAndrew FilerJanet M LordPublished in: Scientific reports (2018)
Galectin-9 (Gal9) has been postulated to have anti-inflammatory properties based on the ability of exogenous Gal9 to induce apoptosis in synovial fibroblasts in animal models of rheumatoid arthritis (RA). Here we aimed to assess the potential role of endogenous Galectins, including Gal9, in the inflammatory pathology of the RA synovium in humans. Firstly expression of Galectins 1-9 was determined in synovial fibroblasts (RASF) and dermal fibroblasts (DF) isolated from RA patients, the latter representing a non-inflamed site. We then further challenged the cells with pro-inflammatory TLR agonists and cytokines and assessed Galectin expression. Gal9 was found to be differentially and abundantly expressed in RASF compared to DF. Agonists of TLR3 and TLR4, along with IFNgamma were also found to induce Gal9 expression in RASF. siRNA was then used to knock-down Gal9 expression in RASF and the effects of this on apoptosis and cell viability were assessed. Increased apoptosis was observed in RASF following Gal9 knock-down. We conclude that, unlike exogenous Gal9, endogenous Gal9 is protective against apoptosis and enhances synovial fibroblast viability suggesting that its role in RA is both pathogenic and pro-inflammatory.
Keyphrases
- rheumatoid arthritis
- cell cycle arrest
- oxidative stress
- endoplasmic reticulum stress
- poor prognosis
- cell death
- disease activity
- induced apoptosis
- toll like receptor
- ankylosing spondylitis
- immune response
- pi k akt
- binding protein
- endothelial cells
- interstitial lung disease
- anti inflammatory
- long non coding rna
- newly diagnosed
- nuclear factor
- cell proliferation
- patient reported outcomes