Compression loading-induced stress responses in intervertebral disc cells encapsulated in 3D collagen constructs
Wai Hon Chooi1, Barbara Pui Chan1
1Tissue Engineering Laboratory, Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong Special Administrative Region, China.
Scientific Reports
|May 21, 2016
Summary
Compression loading on nucleus pulposus cells (NPCs) activates the heat shock response (HSR) and suppresses the unfolded protein response (UPR). This cellular stress response in NPCs may enhance cell survival under mechanical stress.
Area of Science:
- Biomedical Engineering
- Cell Biology
- Biochemistry
Background:
- Cellular stress responses protect cells from environmental damage.
- Intervertebral disc cells exhibit stress responses to various stimuli.
- The impact of compression loading on nucleus pulposus cells (NPCs) stress response is not well understood.
Purpose of the Study:
- To investigate the effect of compression loading on the cellular stress response in NPCs.
- To analyze the expression of heat shock response (HSR) and unfolded protein response (UPR) genes under mechanical stress.
- To determine the role of stress response genes in NPC survival following compression.
Main Methods:
- Utilized an in vitro collagen microencapsulation model for NPCs.
- Applied compression loading with varying strain and duration.
- Assessed cell viability, and gene/protein expression (HSR and UPR markers).
Main Results:
- Longer compression durations upregulated HSR genes (HSP70, HSP27) and downregulated UPR genes.
- Gene expression changes persisted even after load removal.
- No significant increase in apoptosis was observed, suggesting a protective role of stress response.
Conclusions:
- Mechanical compression induces a distinct cellular stress response in NPCs.
- HSR and UPR gene expression are modulated by compression loading duration and intensity.
- Stress response pathways may contribute to NPC survival under mechanical stress.
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