THU0077 CADHERINS GUIDE THE DIRECTIONAL MIGRATION OF THE SYNOVIOCYTES IN RHEUMATOID ARTHRITIS
Authors: J. H. Kang, S. Ahamed, K. H. Sa, S. W. Han, Y. M. Kang
Journal: Annals of the Rheumatic Diseases (2020)

Background: Aggressiveness of synoviocytes and collective migration of organized synovial tissues play a key role in the pathogenesis of pannus invasion into adjacent joint structure. Interactions among synovial cells for grouped movement, however, have not been properly elucidated. Objectives: We hypothesized that cadherins which have functions on the synovial invasion in RA, may play a critical role in collective migration of rheumatoid synoviocytes. Methods: Cadherins expression patterns on the synoviocytes isolated from patients with RA were evaluated using RT-PCR, flow cytometry, and western blot analysis. Mesenchymal and epithelial phenotypes were examined in cadherin overexpressing cell line by flow cytometry. L-cells with overexpression of CDH2 (CDH2 hi ), CDH11 (CDH11 hi ) , and combination of CDH2/CDH11 (CDH2 hi /CDH11 hi ) were prepared. Migration of cells was observed by taking time-lapse images with laser confocal microscope. In vitro collective migration and directional movement in response to inflammatory mediators and different matrix rigidity were evaluated. In vivo homing of CDH2 hi /CDH11 hi -L-cells into joint tissues was performed in collagen induced arthritis (CIA) mouse . In vivo and ex vivo migration pattern of CDH11 hi -L-cells were investigated in nude mice using optical imaging system. Results: In rheumatoid synovial tissues, CDH2 and CDH11 were highly expressed compared to synovial tissues from osteoarthritis. CDH2 and CDH11 were also highly expressed on synovial fibroblasts isolated from RA. Phenotype analysis of mesenchymal and epithelial cells in CDH11 hi -L-cells and CDH2 hi /CDH11 hi -L-cells showed increased expression of α5β1, CD44s, vimentin, and α-SMA compared with MOCK-L-cells. We then analyzed the pattern of migration of MOCK, CDH2 hi , CDH11 hi , and CDH2 hi /CDH11 hi -L-cells using time lapse images. During migration over a hard ECM, CDH2 hi and CDH11 hi -L cells represented higher aspect ratio compare to a soft ECM. Aspect ratio relatively found lower in CDH2 hi /CDH11 hi -L-cell lines than MOCK cells. CDH2 hi /CDH11 hi -L-cells showed significantly higher migration velocity and Euclidean distance with narrower angle of migratory directions in a cytokine mediated migration. Compared to the MOCK cells, persistence ratio and aspect ratio of migration were also higher in CDH2 hi , CDH11 hi , and CDH2 hi /CDH11 hi -L-cells. CDH2 hi /CDH11 hi -L-cells collectively migrated with the formation of leader and follower cells. In a chemokine mediated hard stiffness of ECM, durotaxis was observed in CDH11 hi -L-cells. After 24 hours of intraarticular knee injection in CIA mouse, higher number of CDH2 hi /CDH11 hi -L-cells invaded into the cartilage than MOCK cells. In vivo migration of CDH2 hi /CDH11 hi -L-cells was also found towards the chemokine and cartilage mixed matrigel plug in the subcutaneous space of mice. Conclusion: The expression of CDH2 and CDH11 promotes directional migration of synoviocytes, indicating the potential role of these cadherins on the pannus tissues in the invasion into adjacent joint structure in RA. References: [1]Noss EH, Chang SK, Watts GFM, Brenner MB. Cadherin-11 engagement modulates matrix metalloproteinase production by rheumatoid arthritis synovial fibroblasts. Arthritis Rheum. 2011 Dec; 63(12): 3768–3778 Disclosure of Interests: None declared