A RIPK2-associated macrophage program links mycobacterial sensing to osteoclastogenesis in bone tuberculosis

In bone tuberculosis, Mycobacterium tuberculosis (Mtb) infection triggers inflammatory bone destruction, but the macrophage programs that convert Mtb signals into osteoclastogenesis remain poorly defined.

We generated single-cell RNA-seq data from human spinal tuberculosis lesions and integrated them with public H3K27ac ChIP-seq, RNA-seq, Hi-C, and motif data. Key findings were validated in primary macrophages stimulated with Mtb lysate.

We identified 64 Mtb-induced super-enhancers, and integrated analysis prioritized RIPK2 as a candidate. Lesion-associated myeloid populations showed enhanced inflammatory and osteoclast-priming signatures, followed a mononuclear phagocyte-to-osteoclast trajectory, and exhibited a linear correlation between RIPK2 expression and osteoclast score. In mice, RIPK2 localized to CTSK-positive bone interfaces. In vitro, Mtb stimulation induced Il1b, Nfkbiz, and Tnfrsf11a expression, IL-1β secretion, and surface RANK upregulation; these responses were suppressed by the RIPK2 inhibitor GSK583.

These findings link RIPK2 to both macrophage inflammatory signaling and osteoclastogenesis in bone tuberculosis, suggesting that RIPK2 may be a target for limiting infection-driven bone destruction.