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Updated: Dec 20, 2025
10:30
Sequential In vivo Imaging of Osteogenic Stem/Progenitor Cells During Fracture Repair
Published on: May 23, 2014
10.9K
Thrombospondin-2 spatiotemporal expression in skeletal fractures
Robert L Zondervan1,2,3, Daniel C Jenkins1, John D Reicha1
1Department of Orthopaedics, University of Michigan Medical School, Ann Arbor, Michigan.
Summary
Thrombospondin-2 (TSP2) marks mesenchymal progenitor cells (MSCs) during fracture healing. This discovery offers a new way to identify and potentially target MSCs for improved bone repair therapies.
Area of Science:
- Biomedical Engineering
- Cell Biology
- Regenerative Medicine
Background:
- Fracture healing depends on mesenchymal progenitor cells (MSCs).
- Identifying specific MSC markers is crucial for developing fracture healing therapeutics.
- Thrombospondin-2 (TSP2) expression increases during early fracture healing, but its cellular source is unknown.
Purpose of the Study:
- To identify the cell population expressing thrombospondin-2 (TSP2) during fracture healing.
- To characterize TSP2-expressing cells using reporter mice, flow cytometry, and in vitro assays.
- To determine if TSP2 can serve as a marker for periosteal MSCs.
Main Methods:
- Utilized a TSP2 GFP reporter mouse model and a murine fracture model.
- Analyzed TSP2 expression during different fracture healing phases (inflammatory, soft callus, hard callus).
- Employed flow cytometry and colony formation assays to characterize TSP2-expressing cells.
Main Results:
- TSP2 expression was observed in periosteal cells and undifferentiated callus cells.
- TSP2-expressing cells were positive for traditional MSC markers.
- In vitro assays confirmed TSP2 expression in colony-forming MSCs, but not in chondrocytes.
Conclusions:
- TSP2 is expressed by undifferentiated MSCs during fracture healing.
- TSP2 expression is downregulated in chondrocytes.
- TSP2 represents a promising new marker for identifying MSCs in early fracture healing, aiding therapeutic development.
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