Abstract
OBJECTIVE: Angiogenesis is crucial in RA disease progression. Lymphotoxin β receptor (LTβR)-induced activation of the non-canonical nuclear factor-κB (NF-κB) pathway via NF-κB-inducing kinase (NIK) has been implicated in this process. Consequently, inhibition of this pathway may hold therapeutic potential in RA. We describe a novel three-dimensional (3D) model of synovial angiogenesis incorporating endothelial cells (ECs), RA fibroblast-like synoviocytes (RAFLSs) and RA synovial fluid (RASF) to further investigate the contributions of NF-κB in this process.
METHODS: Spheroids consisting of RAFLSs and ECs were stimulated with RASF, the LTβR ligands LTβ and LIGHT, or growth factor bFGF and VEGF, followed by quantification of EC sprouting using confocal microscopy and digital image analysis. Next, the effects of anginex, NIK-targeting siRNA (siNIK), LTβR-Ig fusion protein (baminercept) and a novel pharmacological NIK inhibitor were investigated.
RESULTS: RASF significantly promoted sprout formation, which was blocked by the established angiogenesis inhibitor anginex (P < 0.05). LTβ and LIGHT induced significant sprouting (P < 0.05), as did bFGF/VEGF (P < 0.01). siNIK pre-treatment of ECs led to reductions in LTβR-induced vessel formation (P < 0.05). LTβR-Ig not only blocked LTβ- or LIGHT-induced sprouting, but also RASF-induced sprouting (P < 0.05). The NIK inhibitor blocked angiogenesis induced by LTβ, LIGHT, growth factors (P < 0.05) and RASF (P < 0.01).
CONCLUSION: We present a novel 3D model of synovial angiogenesis incorporating RAFLSs, ECs and RASF that mimics the in vivo situation. Using this system, we demonstrate that non-canonical NF-κB signalling promotes neovascularization and show that this model is useful for dissecting relative contributions of signalling pathways in specific cell types to angiogenic responses and for testing pharmacological inhibitors of angiogenesis.
Original language | English |
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Pages (from-to) | 294-302 |
Number of pages | 9 |
Journal | Rheumatology (Oxford, England) |
Volume | 56 |
Issue number | 2 |
Early online date | 2016 |
DOIs | |
Publication status | Published - Feb 2017 |
Keywords
- Arthritis, Rheumatoid
- Cells, Cultured
- Endothelial Cells
- Fibroblast Growth Factors
- Humans
- Journal Article
- Lymphotoxin beta Receptor
- Lymphotoxin-beta
- Microscopy, Confocal
- NF-kappa B
- Neovascularization, Pathologic
- Peptides
- Protein-Serine-Threonine Kinases
- RNA, Small Interfering
- Recombinant Fusion Proteins
- Signal Transduction
- Synovial Fluid
- Synovial Membrane
- Synoviocytes
- Tumor Necrosis Factor Ligand Superfamily Member 14
- Vascular Endothelial Growth Factor A