Osteoclast Heterogeneity in Osteoarthritis: From Single-Cell Microenvironments to Program-Specific Therapeutic...

Area of Science:

• Biomedical Science
• Orthopedics
• Cell Biology

Background:

• Osteoarthritis (OA) is a major cause of disability with limited disease-modifying treatments.
• Subchondral bone remodeling, driven by osteoclasts, is an early OA hallmark contributing to structural damage and pain.
• Previous therapies targeting osteoclasts have shown inconsistent results, highlighting the need for a deeper understanding of osteoclast biology.

Purpose of the Study:

• To review recent advances in understanding osteoclast heterogeneity in osteoarthritis.
• To examine how osteoclast-lineage diversity influences subchondral bone remodeling and OA pathology.
• To explore the potential of this new framework for patient stratification and targeted OA therapies.

Main Methods:

• Synthesis of recent high-resolution evidence, including single-cell and spatial multi-omics studies.
• Analysis of osteoclast heterogeneity across different disease stages and osteochondral microenvironments.
• Examination of the contribution of distinct osteoclast-lineage programs to OA pathogenesis.

Main Results:

• Osteoclasts are not a homogeneous population but exhibit significant heterogeneity in origin, state, function, and adaptation.
• This heterogeneity is organized across OA disease stages and osteochondral niches.
• Distinct osteoclast-lineage programs contribute to subchondral remodeling, angiogenesis, and pain in OA.

Conclusions:

• A state-spectrum framework, acknowledging osteoclast-lineage heterogeneity, is essential for advancing OA research.
• Understanding this heterogeneity can guide patient stratification and the development of mechanism-matched, program-specific OA therapies.
• Targeting specific osteoclast-lineage programs offers a promising avenue for novel OA treatments.