AAV-mediated Overexpression of IL-10 Mitigates the Inflammatory Cascade in Stimulated Equine Chondrocyte Pellets.

Abstract

Following joint trauma, a posttraumatic inflammatory cascade drives degeneration of the joint. We aimed to assess whether transduction of chondrocytes with AAV5 overexpressing the immunomodulatory cytokine IL-10 would have protective effects in pellet cultures stimulated with IL-1β. Chondrocytes were isolated from 3 healthy horses and were transduced with AAV5-IL-10 at a dose of 1 x 105vg/cell. Chondrocyte pellets were formed by centrifugation and were stimulated with IL-1β starting 48 hours following transduction. After 2, 6 and 14 days in culture, supernatants were collected for cytokine analysis and RNA was isolated from cells for gene expression analysis. Pellets were also collected for biochemical analysis. Transduction of chondrocytes led to significant increases in IL-10 expression. IL-10 expression was further enhanced by IL-1β stimulation. IL-10 overexpression led to significantly decreased expression of IL-1β and ADAMTS4. PGE2 synthesis was also significantly decreased. IL-1β mediated suppression of GAG synthesis was not rescued by IL-10. Overexpression of IL-10 modulates the inflammatory response in chondrocytes, which may mitigate some of the deleterious effects of pro-inflammatory cascades in the posttraumatic joint. AAV5-IL-10 led to efficient and sustained overexpression of IL-10 in chondrocytes and could represent a viable treatment option for preventing osteoarthritis.