Blockade of IL-33 signalling attenuates osteoarthritis.

OBJECTIVES

Osteoarthritis (OA) is the most common form of arthritis characterised by cartilage degradation, synovitis and pain. Disease modifying treatments for OA are not available. The critical unmet need is to find therapeutic targets to reduce both disease progression and pain. The cytokine IL-33 and its receptor ST2 have been shown to play a role in immune and inflammatory diseases, but their role in osteoarthritis is unknown.

METHODS

Non-OA and OA human chondrocytes samples were examined for IL-33 and ST2 expression. Novel inducible cartilage specific knockout mice (IL-33) and inducible fibroblast-like synoviocyte knockout mice (IL-33) were generated and subjected to an experimental OA model. In addition, wild-type mice were intra-articularly administered with either IL-33- or ST2-neutralising antibodies during experimental OA studies.

RESULTS

IL-33 and its receptor ST2 have increased expression in OA patients and a murine disease model. Administering recombinant IL-33 increased OA and pain . Synovial fibroblast-specific deletion of IL-33 decreased synovitis but did not impact disease outcomes, whilst cartilage-specific deletion of IL-33 improved disease outcomes . Blocking IL-33 signalling also reduced the release of cartilage-degrading enzymes in human and mouse chondrocytes. Most importantly, we show the use of monoclonal antibodies against IL-33 and ST2 attenuates both OA and pain .

CONCLUSION

Overall, our data reveal blockade of IL-33 signalling as a viable therapeutic target for OA.