AB0044 ENDOTHELIAL CELL AND RHEUMATOID ARTHRITIS SYNOVIAL FIBROBLAST MIGRATION AND ADHESION ARE ALTERED BY ACTIVIN/FOLLISTATIN

Background: Activin A and follistatin belong to an anti-inflammatory auto-regulatory cycle. Patients with rheumatoid arthritis (RA) have increased activin levels in the synovial fluid tissue. During inflammation, is released systemically, then inducing its antagonist follistatin. This negative feedback active different cell types but not RA fibroblasts (SF). Fibroblasts interact endothelial cells inflamed tissues angiogenesis. Objectives: Evaluation of role on RASF interactions. Methods: synovium was used for isolation, HUVEC were commercially obtained. stimulated mono- coculture. Direct: together HUVEC; indirect: inserts separated by a membrane from RASF. Stimuli: 15ng/ml, 500ng/ml, IL-1β 1ng/ml. Proliferation analyzed BrdU assay. Calcein-AM stained. Cells transferred 24-well plates after 18h stimulation. After adhesion 1h, non-adherent removed shaking 3x 5 min. Afterwards, fluorescent quantified. For flow-adhesion assay, cultured rattail collagen coated capillary slides. 4h TNFα, TNFα+activin or TNFα+follistatin. stimulation, 2x10^6 resuspended 20ml medium sent through capillaries. Two 1min videos recorded (18.4ml/h, 30.5ml/h). Settings: TNFα-stimulated wit TNFα A+TNFα follistatin+ TNFα. migration assays, 2% FCS 1x10^5 placed (8µm membrane) into wells 10% (control: 2%FCS vs. 2%FCS) with, IL-1, IL-1+activinA IL-1+follistatin. 16h, migrated scratch-assay 4x10^5 overnight, scratched stimulated, afterwards 3 pictures per scratch taken at start, 10h every 1.5h. migrating area Results: IL-1 induced all settings. IL-1-induced release reduced monoculture both cocultures compared alone monoculture. IL-6 indirect coculture direct Follistatin did alter responses. VEGF altered A. Short-term showed no significant influence (n=4). Flow assay adherence/rolling Migration assays that decreased without difference between effects mediated IL-1+follistatin Scratch dicrect greater unstimulated Conclusion: In effect dominant leading release. However, HUVECs during cell-contact types. The interaction seems prevent reducing HUVECs. impact short-term first observations show, alters selectin-mediated under flow conditions. shows enhanced decrease more prominent than although gap highest Disclosure Interests: None declared