Effects of genipin crosslinking on mechanical cell-matrix interaction in 3D engineered tendon constructs

Area of Science:

• Biomedical Engineering
• Cell Biology
• Tissue Engineering

Background:

• Cells exert forces on the extracellular matrix (ECM).
• The influence of ECM mechanical properties on cellular forces is not fully understood.
• Understanding cell-matrix interactions is crucial for tissue homeostasis.

Purpose of the Study:

• To quantify the impact of matrix rigidity on cell-matrix interactions.
• To investigate how matrix cross-linking affects endogenous cellular forces in engineered human tendon constructs.

Main Methods:

• Engineered human tendon constructs were treated with genipin (cross-linking agent) or beta-aminopropionitrile (BAPN, cross-linking inhibitor).
• Cell-generated tissue re-tensioning and stress-relaxation were measured using a novel force monitor.
• Mechanical failure testing and biochemical analysis were performed.

Main Results:

• Increasing genipin concentration decreased endogenous re-tension after unloading.
• Peak stress increased with high genipin concentrations but decreased with BAPN treatment.
• Tendon construct stiffness increased with high genipin concentrations and decreased significantly with BAPN treatment.
• Cell viability was generally unaffected, except at the highest genipin concentration.

Conclusions:

• Human tendon fibroblasts regulate force exertion inversely to matrix cross-linking capacity, independent of matrix stiffness.
• An interaction between cell force generation and cross-linking plays a role in tissue mechanical homeostasis.
• These findings provide insights into the mechanobiology of tendon tissue.