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RGD-dependent integrins are mechanotransducers in dynamically compressed tissue-engineered cartilage constructs
Linda M Kock1, Ronny M Schulz, Corrinus C van Donkelaar
1Department of Biomedical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands. l.m.kock@tue.nl
Journal of Biomechanics
|August 7, 2009
Summary
Blocking RGD-dependent integrins affects extracellular matrix gene expression and synthesis in cartilage cells. This role is dependent on loading frequency, influencing chondrocyte mechanotransduction.
Area of Science:
- Biomedical Engineering
- Cell Biology
- Biochemistry
Background:
- Integrins function as mechanoreceptors in articular cartilage.
- Understanding chondrocyte response to mechanical loading is crucial for cartilage repair.
Purpose of the Study:
- To investigate the role of RGD-dependent integrins in mediating mechanical loading effects on chondrocytes.
- To examine how blocking these integrins impacts extracellular matrix (ECM) gene expression and protein synthesis.
Main Methods:
- Porcine articular chondrocytes were cultured in agarose constructs.
- Constructs were subjected to compressive loading (15% strain) at 0.33 Hz and 1 Hz.
- RGD-dependent integrins were blocked using GRGDSP.
- ECM gene expression (aggrecan, collagen II, MMP-3) and sGAG content were analyzed.
Main Results:
- Loading at 0.33 Hz increased aggrecan and MMP-3 mRNA, but not collagen II mRNA; GRGDSP blocked these changes.
- Loading at 1 Hz increased all tested mRNA levels, with GRGDSP counteracting these effects.
- Low-frequency loading decreased sGAG, while high-frequency loading increased it; integrin blocking affected long-term sGAG only at 1 Hz.
Conclusions:
- RGD-dependent integrins act as mechanotransducers in chondrocytes under mechanical loading.
- The role of integrins in regulating ECM gene expression and matrix biosynthesis is dependent on loading frequency.
- These findings highlight the importance of mechanical stimuli and integrin signaling in cartilage homeostasis and potential therapeutic strategies.
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