Positive and negative cooperativity of TNF and Interferon-γ in regulating synovial fibroblast function and B cell survival in fibroblast/B cell co-cultures

Abstract

Synovial fibroblasts (SF) were reported to produce B cell activating factor (BAFF) in response to stimulation with interferon-γ (IFN-γ) or tumor necrosis factor (TNF). However, the influence of these pro-inflammatory cytokines on other receptors/ligands of the TNF superfamily or associated cytokine receptors in SF has not been investigated yet. Here we show the differential regulation of BAFF (CD257), Fn14 (CD266), TACI (CD267), BAFF-R (CD268), BCMA (CD269), CD40 ligand (CD40L, CD154), IFN-γR (CD119), Leptin receptor (ObR, CD295), VCAM-1 (CD106) and membrane TGF-β in isolated Sf and the impact of ifn-γ/TNF co-incubation on proliferation, IL-6 and IL-8 production. In addition, the impact of differentially stimulated SF on B cell survival in co-cultures was assessed. Surface cytokines and cytokine receptors were detected by flow cytometry. Soluble cytokine receptors and cytokines were quantified by ELISA. Proliferation was assessed by cell titer blue. Murine B cell survival in fibroblast/ B cell co-cultures was determined by annexin V/propidium iodide staining and flow cytometry. IFN-γ together with TNF synergistically and significantly increased the cell surface levels of BAFF, Fn14, TACI, BAFF-R, BCMA, CD40L, ObR and IFN-γR in rheumatoid arthritis SF after 72 h incubation. Soluble BAFF was only induced by IFN-γ and inhibited by TNF. Addition of TWEAK had no influence on proliferation or IL-8 production but decreased TNF-induced IL-6 production, whereas APRIL, BAFF and leptin did not modulate TNF or TNF/IFN-γ-induced proliferation or cytokine production. Proliferation was increased by TNF and further enhanced by the addition of IFN-γ. In co-culture experiments, SF stimulated with TNF/IFN but not TNF or IFN-γ alone increased shedding of VCAM-1 and expression of membrane TGFβ, which was associated with reduced survival of murine B cells. ifn-γ and TNF regulate the expression of TNF family member cytokines and associated receptors. Ligation of IFN-γR and Fn14 under proinflammatory conditions modulated IL-6/IL-8 production and proliferation. In B cell/SF co-cultures, the combination of TNF/IFN reduced B cell survival possibly via enhanced VCAM-1 shedding and/ or increased tGf-β production. ifn-γ is necessary for the observed effects on B cell survival and SF cytokine production and emphasizes its anti-inflammatory role in rheumatoid arthritis. In rheumatoid arthritis (RA), interferon-γ (IFN-γ) levels are increased in synovial fluid and concomitantly, synovial fluid mononuclear cells show increased IFN-γ mRNA levels 1,2. IFN-γ has a dual role in chronic inflammation since it does increase the presentation of antigens via induction of MHC class II molecules in synovial fibroblasts

Bi-directional communication: Conversations between fibroblasts and immune cells in systemic sclerosis

“…This occurs in a BAFF dependent manner and requires direct contact between FLS and B cells. FLS express the membrane bound form of BAFF following stimulation with IFN-γ/TNF-α and promote B cell survival[163]. A study by Francois et al, found that contact between SSc dermal fibroblasts and B cells promoted collagen production, however SSc fibroblasts did not secrete BAFF or express the BAFF receptor[6].…”

Adipose/Connective Tissue From Thyroid-Associated Ophthalmopathy Uncovers Interdependence Between Methylation and Disease Pathogenesis: A Genome-Wide Methylation Analysis

“…In TAO patients' retrobulbar space, elevated VCAM-1 in endothelial cells has been detected to induce the recruitment of lymphocytes (Heufelder and Scriba, 1996). Except for endothelial cells, fibroblasts can express VCAM-1 in response to TNF-a, which has been proved in autoimmune rheumatoid arthritis (Lowin et al, 2020). In TAO patients, VCAM-1 can also be elevated by activated immune cells, such as Th17 cells, and mediates orbital fibrosis and adipogenesis (Fang et al, 2017(Fang et al, , 2021.…”

The Role of RhoH in TCR Signalling and Its Involvement in Diseases

“…Interestingly, IFN-γ overproduction is involved in cancer progression by stimulating tumour growth with immunoevasive properties [ 94 ]. This pro-oncogenic property of IFN-γ is probably due to its ability to regulate B cell-activating factor, BAFF production [ 95 , 96 ], a cytokine involved in B cell survival and differentiation. Increased production of BAFF was observed in SLE, particularly in the pathogenesis of lupus nephritis, causing an overproduction of T cell-dependent B cell pathogenic autoantibodies [ 95 , 97 ].…”