Osteoclast Biology in Immune Modulation and Bone Homeostasis

Bone homeostasis relies on a dynamic equilibrium between bone formation by osteoblasts and bone resorption by osteoclasts, a process tightly regulated by immune signals. Osteoclasts derive from monocyte–macrophage lineage precursors under the influence of macrophage colony-stimulating factor and receptor activator of NF-κB ligand, fusing into multinucleated cells that acidify and enzymatically degrade mineralised matrix. Beyond resorption, these cells shape haematopoietic niches, influence myeloid lineage commitment and modulate adaptive responses via cytokines such as TNF-α, IL-6 and IFN-γ. Dysregulation of osteoimmune crosstalk underlies osteoporosis, rheumatoid arthritis and inflammatory bowel disease, highlighting the global significance of targeting osteoclast biology for novel therapies and improved management of skeletal and immune disorders.

Research from Nature Portfolio

Recent studies using intravital imaging have revealed that direct contact between mature osteoblasts and osteoclasts transiently inhibits proton secretion and bone resorption. In the steady state, these cells occupy discrete territories, but intermittent cell–cell interfaces coincide with suppressed osteoclastic activity. Intermittent parathyroid hormone administration increases mixed cell distributions and contact frequency, shifting the balance towards bone formation. This work establishes direct intercellular inhibition as a fundamental mechanism in bone remodelling, suggesting avenues to modulate osteoclast function with spatial and temporal precision.

Osteoclast Biology in Immune Modulation and Bone Homeostasis publication trend

The graph below shows the total number of articles in osteoclast biology in immune modulation and bone homeostasis across all publications each year (not limited to Nature Index journals).

Technical terms

Osteoclast: Multinucleated cell derived from monocyte–macrophage lineage responsible for bone resorption.

Osteoblast: Bone-forming cell originating from mesenchymal stem cells that synthesises bone matrix.

RANKL: Receptor activator of NF-κB ligand, key cytokine that drives osteoclast differentiation and activation.

Haematopoietic niche: Bone marrow microenvironment supporting the maintenance and differentiation of blood and immune cells.

TRAP: Tartrate-resistant acid phosphatase, enzyme marker of osteoclast differentiation and bone-resorbing activity.

References

1. Immune Function and Diversity of Osteoclasts in Normal and Pathological Conditions. Frontiers in Immunology (2019).
2. Direct cell–cell contact between mature osteoblasts and osteoclasts dynamically controls their functions in vivo. Nature Communications (2018).
3. Dysregulated myeloid differentiation in colitis is induced by inflammatory osteoclasts in a TNFα-dependent manner. Mucosal Immunology (2024).
4. JAK inhibition ameliorates bone destruction by simultaneously targeting mature osteoclasts and their precursors. Inflammation and Regeneration (2023).
5. Specific inflammatory osteoclast precursors induced during chronic inflammation give rise to highly active osteoclasts associated with inflammatory bone loss. Bone Research (2022).