Small Extracellular Vesicles from adipose derived stromal cells significantly attenuate in vitro the NF-κB dependent inflammatory/catabolic environment of osteoarthritis.

The therapeutic ability of Mesenchymal Stem/Stromal Cells to address osteoarthritis (OA) is mainly related to the secretion of biologically active factors, which can be found within their secreted Extracellular Vesicles including small Extracellular Vesicles (sEV). Aim of this study was to investigate the effects of sEV from adipose derived stromal cells (ADSC) on both chondrocytes and synoviocytes, in order to gain insights into the mechanisms modulating the inflammatory/catabolic OA environment. sEV, obtained by a combined precipitation and size exclusion chromatography method, were quantified and characterized, and administered to chondrocytes and synoviocytes stimulated with IL-1β. Cellular uptake of sEV was evaluated from 1 to 12 h. Gene expression and protein release of cytokines/chemokines, catabolic and inflammatory molecules were analyzed at 4 and 15 h, when p65 nuclear translocation was investigated to study NF-κB pathway. This study underlined the potential of ADSC derived sEV to affect gene expression and protein release of both chondrocytes and synoviocytes, counteracting IL-1β induced inflammatory effects, and provided insights into their mechanisms of action. sEV uptake was faster in synoviocytes, where it also elicited stronger effects, especially in terms of cytokine and chemokine modulation. The inflammatory/catabolic environment mediated by NF-κB pathway was significantly attenuated by sEV, which hold promise as new therapeutic strategy to address OA.