IL7-IL7R Interaction Mediates Fibroblast-Driven Macrophage-to-Osteoclast Differentiation in Periodontitis

Area of Science:

• Immunology
• Oral Biology
• Cell Biology

Background:

• Periodontitis is a chronic inflammatory disease leading to alveolar bone destruction.
• Macrophage subsets play critical roles in the pathogenesis of periodontitis, but specific osteoclastogenic populations remain poorly defined.

Purpose of the Study:

• To identify osteoclastogenic macrophage subsets in periodontitis.
• To elucidate the regulatory mechanisms driving their osteoclastogenic potential.
• To explore potential therapeutic targets for periodontitis-associated bone loss.

Main Methods:

• Integrated single-cell RNA sequencing from human and murine periodontitis datasets.
• Functional enrichment, cell-cell communication, and machine learning analyses.
• In vitro and in vivo validation using assays like ELISA, TRAP staining, micro-CT, qPCR, flow cytometry, and immunofluorescence.

Main Results:

• Identified Interleukin-7 Receptor-positive (IL7R+) macrophages as having significant osteoclast differentiation potential.
• The Interleukin-7 (IL7)/IL7R signaling axis was confirmed to drive osteoclast differentiation.
• IL7R+ macrophages increased in periodontitis, and targeting IL7/IL7R signaling mitigated bone resorption.

Conclusions:

• IL7R+ macrophages are identified as potential osteoclast precursors in periodontitis.
• The IL7/IL7R signaling pathway is a critical therapeutic target for periodontitis.
• Inhibition of IL7R presents a potential strategy to prevent bone loss in periodontitis.