Targeting IFN-I driven tertiary lymphoid structures halts B cell-mediated bone loss in periodontitis

Area of Science:

• Immunology
• Periodontology
• Pathology

Background:

• Lymphocytes are key in periodontitis, producing RANKL.
• Tertiary lymphoid structures (TLSs) are ectopic lymphoid aggregates involved in local immune responses.

Purpose of the Study:

• Investigate the role and formation of TLSs in periodontitis.
• Elucidate the mechanism of TLS organization by gingival fibroblasts.
• Determine the contribution of TLS-associated B cells to periodontitis pathogenesis.
• Evaluate the therapeutic potential of targeting IFN-I signaling.

Main Methods:

• Multiplex immunohistochemistry staining to analyze TLS formation and maturation.
• Single-cell RNA sequencing and in vitro assays to identify fibroblast activation pathways.
• Mouse periodontitis model to assess B cell activity and bone resorption.
• Intervention studies inhibiting IFN-I signaling.

Main Results:

• TLSs form and mature with increasing inflammation severity, correlating with poorer surgical outcomes.
• Oral pathogens activate the IFN-I-IRF7 axis in fibroblasts, inducing a CXCL13-producing subtype that drives TLS organization.
• Activated B cells within TLSs promote osteoclastogenesis and bone resorption via RANKL.
• IFN-I inhibition suppressed TLS formation, RANKL production, and periodontitis-associated bone loss.

Conclusions:

• TLSs act as pathological hubs coordinating B cell-mediated bone destruction in periodontitis.
• The IFN-I signaling pathway is crucial for TLS formation and periodontitis progression.
• Targeting IFN-I signaling offers a potential therapeutic strategy for periodontitis.