Artemin and its cognate receptor, GFRα3, play a function role in osteoarthritis pain

Osteoarthritis associated pain (OA-pain) is a significant global problem. OA-pain limits limb use and mobility, and is associated with widespread sensitivity. Therapeutic options are limited, and the ones that are available are often associated with side or adverse effects. The lack of therapeutic options is partly due to a lack of understanding of clinically relevant underlying neural mechanisms of OA-pain. In previous work in naturally occurring OA-pain in dogs, we identified potential signaling molecules (artemin/GFR3) that were upregulated. Here, we use multiple approaches including knockout mice, immunological suppression in a mouse model of OA, and clinically relevant measures of sensitivity and limb use to explore the functional role of artemin/GFR3 signaling in OA-pain. We found the monoiodoacetate (MIA)-induced OA model in mice is associated with decreased limb use and hypersensitivity. GFR3 expression is increased in sensory neurons. Exogenous artemin induces heat, cold and mechanical hypersensitivity, and anti-artemin monoclonal antibody administration reverses this hypersensitivity and restores limb use in mice with MIA-induced OA pain. Our results provide a molecular basis of arthritis pain linked with artemin/GFR3 signaling and indicate that further work is warranted to investigate the neuronal plasticity and the pathways that drive pain in OA.