Cytokine-directed cellular cross-talk imprints synovial pathotypes in rheumatoid arthritis

• Published in: Annals of the rheumatic diseases Vol. 82; no. 9; p. 1142
• Main Authors: Kugler, Maximilian, Dellinger, Mirjam, Kartnig, Felix, Müller, Lena, Preglej, Teresa, Heinz, Leonhard X, Simader, Elisabeth, Göschl, Lisa, Puchner, Stephan E, Weiss, Sebastian, Shaw, Lisa E, Farlik, Matthias, Weninger, Wolfgang, Superti-Furga, Giulio, Smolen, Josef S, Steiner, Guenter, Aletaha, Daniel, Kiener, Hans P, Lewis, Myles J, Pitzalis, Costantino, Tosevska, Anela, Karonitsch, Thomas, Bonelli, Michael
• Format: Journal Article
• Language: English
• Published: England 01-09-2023
• Subjects: Arthritis, Rheumatoid; Cells, Cultured; Cytokines; Fibroblasts - pathology; Humans; Synovial Membrane - pathology; Synoviocytes - pathology; Tumor Necrosis Factor-alpha - pharmacology; Fibroblasts; T-Lymphocyte subsets; Inflammation; Cytokines; Rheumatoid Arthritis
• ISSN: 1468-2060
• DOI: 10.1136/ard-2022-223396

Structural reorganisation of the synovium with expansion of fibroblast-like synoviocytes (FLS) and influx of immune cells is a hallmark of rheumatoid arthritis (RA). Activated FLS are increasingly recognised as a critical component driving synovial tissue remodelling by interacting with immune cells resulting in distinct synovial pathotypes of RA.
Automated high-content fluorescence microscopy of co-cultured cytokine-activated FLS and autologous peripheral CD4
T cells from patients with RA was established to quantify cell-cell interactions. Phenotypic profiling of cytokine-treated FLS and co-cultured T cells was done by flow cytometry and RNA-Seq, which were integrated with publicly available transcriptomic data from patients with different histological synovial pathotypes. Computational prediction and knock-down experiments were performed in FLS to identify adhesion molecules for cell-cell interaction.
Cytokine stimulation, especially with TNF-α, led to enhanced FLS-T cell interaction resulting in cell-cell contact-dependent activation, proliferation and differentiation of T cells. Signatures of cytokine-activated FLS were significantly enriched in RA synovial tissues defined as lymphoid-rich or leucocyte-rich pathotypes, with the most prominent effects for TNF-α. FLS cytokine signatures correlated with the number of infiltrating CD4
T cells in synovial tissue of patients with RA. Ligand-receptor pair interaction analysis identified ICAM1 on FLS as an important mediator in TNF-mediated FLS-T cell interaction. Both, ICAM1 and its receptors were overexpressed in TNF-treated FLS and co-cultured T cells. Knock-down of ICAM1 in FLS resulted in reduced TNF-mediated FLS-T cell interaction.
Our study highlights the role of cytokine-activated FLS in orchestrating inflammation-associated synovial pathotypes providing novel insights into disease mechanisms of RA.