Small extracellular vesicles derived from synovial fibroblasts contain distinct miRNA profiles and contribute to chondrocyte damage in osteoarthritis

Abstract Background Small extracellular vesicles (sEV) derived from synovial fibroblasts (SF) represent a novel molecular mechanism regulating cartilage erosion in osteoarthritis (OA). However, a comprehensive evaluation using disease relevant cells has not been undertaken. The aim of this study was to isolate and characterise sEV from OA SF and to look at their ability to regulate OA chondrocyte effector responses relevant to disease. Profiling of micro (mi) RNA signatures in sEV and parental OA SF cells was performed. Methods SF and chondrocytes were isolated from OA synovial membrane and cartilage respectively (n = 9). sEV were isolated from OA SF (± IL-1β) conditioned media by ultracentrifugation and characterised using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Particle size was confirmed by nanoparticle tracking analysis (NTA). sEV regulation of OA chondrocyte and cartilage effector response was evaluated using qPCR, ELISA and sulphated glycosaminoglycan assay (sGAG). RNA-sequencing was used to establish miRNA signatures in isolated sEV from OA SF. Results OA SF derived sEV were readily taken up by OA chondrocytes, with increased expression of the catabolic gene MMP 13 (p