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Collagen/annexin V interactions regulate chondrocyte mineralization
Hyon Jong Kim1, Thorsten Kirsch
1Musculoskeletal Research Laboratories, Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.
The Journal of Biological Chemistry
|February 19, 2008
Summary
Collagen and annexin V interactions regulate cartilage mineralization by controlling calcium influx in chondrocytes. This discovery sheds light on both physiological and pathological bone development processes.
Area of Science:
- Biochemistry
- Cell Biology
- Orthopedics
Background:
- Physiological mineralization in growth plate cartilage is a tightly controlled process.
- Mineralization occurs in the extracellular matrix, suggesting a role for matrix components.
Purpose of the Study:
- To investigate the direct involvement of collagen, a major extracellular matrix component, in regulating cartilage mineralization.
- To explore the interaction between collagen and annexin V in chondrocytes.
Main Methods:
- Examined interactions between types II and X collagen and cell surface-expressed annexin V.
- Measured intracellular calcium concentration ([Ca(2+)](i)) and alkaline phosphatase activity.
- Manipulated collagen synthesis, annexin V expression, and annexin channel activity.
Main Results:
- Type II and X collagen interact with annexin V, stimulating calcium influx and increasing intracellular calcium levels.
- Enhanced collagen synthesis or annexin V activity increased mineralization.
- Inhibiting collagen secretion or annexin V channel activity decreased mineralization.
Conclusions:
- Interactions between collagen and annexin V are key regulators of growth plate cartilage mineralization.
- These interactions may also play a role in pathological mineralization events in articular cartilage, given annexin V's upregulation.
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