Citation Information: JCI Insight. 2025. https://doi.org/10.1172/jci.insight.184954.
Abstract
Septic arthritis, the most severe joint disease, is frequently caused by Staphylococcus aureus (S. aureus). A substantial proportion of patients with septic arthritis experience poor joint outcomes, often necessitating joint replacement surgery. Here, we show that monocyte depletion confers full protection against bone erosion in a septic arthritis mouse model. In the infected synovium, Ly6Chigh monocytes exhibited increased expression of osteoclastogenesis-related molecules, including CCR2, c-Fms, and RANK. S. aureus lipoproteins induced elevated levels of RANKL, MCSF, and CCL-2 in joints, with synovial fibroblasts identified as the major RANKL producer. Anti-RANKL treatment prevented bone destruction in both local and hematogenous septic arthritis murine models. Importantly, combining anti-RANKL treatment with antibiotics provided robust protection against joint damage. Our results indicate that the infiltration and transformation of monocytes into bone-destructive, osteoclast-like cells are key mechanisms in septic arthritis. Combining anti-RANKL and antibiotic therapy represents a promising therapy against this devastating disease.
Authors
Zhicheng Hu, Meghshree Deshmukh, Anders Jarneborn, Miriam Bollmann, Carmen Corciulo, Pradeep Kumar Kopparapu, Abukar Ali, Mattias N.D. Svensson, Cecilia Engdahl, Rille Pullerits, Majd Mohammad, Tao Jin
