A replicating stem-like cell that contributes to bone morphogenetic protein 2-induced heterotopic bone formation

Area of Science:

• Regenerative Medicine
• Stem Cell Biology
• Skeletal Biology

Background:

• Bone morphogenetic protein 2 (BMP2) induces heterotopic bone formation (HBF), providing a model for lineage tracking.
• Previous methods struggled to identify rare cell populations involved in bone regeneration.

Purpose of the Study:

• To identify and characterize novel stem cell populations involved in BMP2-induced heterotopic bone formation.
• To evaluate the regenerative potential of identified stem cells in vivo.

Main Methods:

• Utilized GLAST-CreERT2:tdTomato red (TR) mice for lineage tracing during BMP2-induced HBF.
• Employed single-cell RNA sequencing (scRNA-seq) to identify cell types and developmental trajectories.
• Isolated and characterized replicating stem-like cells (RSCs) and chondro-osseous progenitors (COPs) using flow cytometry for transplantation experiments.

Main Results:

• Identified a highly replicating stem-like cell (RSC) that differentiates into chondro-osseous progenitors (COPs).
• Transplanted RSCs showed significantly higher contribution (9%) to heterotopic bone compared to COPs (<0.5%).
• Donor-derived RSCs in engrafted bone confirmed their early progenitor nature, differentiating into COPs and mature bone cells.

Conclusions:

• Replicating stem-like cells (RSCs) are potent progenitors in BMP2-induced heterotopic bone formation.
• Single-cell RNA sequencing is effective in detecting rare, critical cell populations like RSCs.
• RSCs demonstrate significant potential for tissue regeneration applications.