Arthritis & Rheumatism, Volume 63,
November 2011 Abstract Supplement
Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Chicago, Illinois November 4-9, 2011.
Aberrant Basal and TLR-Stimulated Expression of TSLP in Rheumatoid Synovial Fibroblasts.
Bombardieri1, Michele, Kam1, Yvonne NW, Filer2, Andrew, Buckley2, Christopher D., Pitzalis1, Costantino
Thymic stromal lymphopoietin (TSLP) is an interleukin-7-like cytokine which is a strong activator of dendritic cells mainly leading to a Th2 polarization. Recent studies in the collagen-induced arthritis (CIA) model demonstrated that TLSP is an important pro-inflammatory cytokine capable of exacerbating disease severity via a T-cell dependent mechanism. Here we investigated the expression of TSLP and its receptor (TSLPR) in the synovium of rheumatoid arthritis (RA) patients and in rheumatoid synovial fibroblasts (RASF), in basal conditions and upon stimulation with Toll-like receptors (TLR) ligands.
mRNA expression of TSLP in RASF, osteoarthritis (OASF) and RA dermal fibroblasts (RADF) in basal conditions or upon stimulation with TLR2, TLR3 and TLR4 ligands was assessed by Taqman PCR (QT-PCR). Intracellular and soluble TSLP protein expression was assessed by immunocytochemistry and ELISA, respectively. The expression of TSLP and TSLPR in the rheumatoid synovium of 40 RA patients was investigated by QT-PCR and immunohistochemistry.
RASF and, to a lesser extent OASF, displayed significantly higher constitutive mRNA expression compared to RADF (between 816 fold basal increase in RASF vs RADF). In vitro stimulation of TLR3 and TLR4, but not TLR2 on RASF led to strong induction of TSLP (~20-fold increase with TLR3) mRNA expression which peaked at 8h and return to baseline values at 48h. In response to TLR3, cytoplasmic staining of TSLP was strongly increased in RASF but not RADF, while soluble TSLP was time-dependently released in the supernatant of TLR3-stimulated RASF (~100pg/ml) but was undetectable in RADF. Finally, expression of TSLP mRNA was observed in all the RA samples examined while TSLPR was significantly increased in patients with follicular synovitis.
Here we demonstrated that the pro-arthritogenic and pro-inflammatory IL-7-like cytokine TSLP and its receptor TSLPR are abundantly expressed in the rheumatoid synovium. In addition, we showed that RASF but not RADF display an aberrant expression of TSLP in basal conditions which is further stimulated upon TLR3 and TLR4 ligations. Overall, these data strongly support a pivotal role for RASF in the dysregulated production of TSLP in the rheumatoid synovium, suggesting that the TSLP/TSLPR pathway contributes to chronic inflammation in RA.
To cite this abstract, please use the following information:
Bombardieri, Michele, Kam, Yvonne NW, Filer, Andrew, Buckley, Christopher D., Pitzalis, Costantino; Aberrant Basal and TLR-Stimulated Expression of TSLP in Rheumatoid Synovial Fibroblasts. [abstract]. Arthritis Rheum 2011;63 Suppl 10 :374