The role of IL-23 receptor signaling in inflammation-mediated erosive autoimmune arthritis and bone remodeling

The IL-23/Th17 axis has been implicated in the development of autoimmune diseases, such as rheumatoid arthritis (RA) and psoriatic arthritis (PsA). RA and PsA are heterogeneous diseases with substantial burden on patients. Increasing evidence suggests that the IL-23 signaling pathway may be involved in the development of autoimmunity and erosive joint damage. IL-23 can act either directly or indirectly on bone forming osteoblasts as well as on bone resorbing osteoclasts. As IL-23 regulates the activity of cells of the bone, it is conceivable that in addition to inflammation-mediated joint erosion, IL-23 may play a role in physiological bone remodeling. In this review, we focus on the role of IL-23 in autoimmune arthritis in patients and murine models, and provide an overview of IL-23 producing and responding cells in autoimmune arthritic joints. In addition, we discuss the role of IL-23 on bone forming osteoblasts and bone resorbing osteoclasts regarding inflammation-mediated joint damage and bone remodeling. At last, we briefly discuss the clinical implications of targeting this pathway for joint damage and systemic bone loss in autoimmune arthritis.