The Role of Inflammasomes in Osteoarthritis and Secondary Joint Degeneration Diseases.
Osteoarthritis is age-related and the most common form of arthritis. The main characteristics of the disease are progressive loss of cartilage and secondary synovial inflammation, which finally result in pain, joint stiffness, and functional disability. Similarly, joint degeneration is characteristic of systemic inflammatory diseases such as rheumatoid arthritis and gout, with the associated secondary type of osteoarthritis. Studies suggest that inflammation importantly contributes to the progression of the disease. Particularly, cytokines TNFα and IL-1β drive catabolic signaling in affected joints. IL-1β is a product of inflammasome activation. Inflammasomes are inflammatory multiprotein complexes that propagate inflammation in various autoimmune and autoinflammatory conditions through cell death and the release of inflammatory cytokines and damage-associated molecule patterns. In this article, we review genetic, marker, and animal studies that establish inflammasomes as important drivers of secondary arthritis and discuss the current evidence for inflammasome involvement in primary osteoarthritis. The NLRP3 inflammasome has a significant role in the development of secondary osteoarthritis, and several studies have provided evidence of its role in the development of primary osteoarthritis, while other inflammasomes cannot be excluded. Inflammasome-targeted therapeutic options might thus provide a promising strategy to tackle these debilitating diseases.