Cell orientation response to cyclically deformed substrates: experimental validation of a cell model

Area of Science:

• Cell biology
• Biophysics
• Mechanical engineering

Background:

• Cellular orientation is influenced by substrate mechanics.
• Bipolar cells exhibit specific responses to mechanical stimuli.
• Understanding cell behavior on deformed surfaces is crucial for tissue engineering.

Purpose of the Study:

• To develop and validate a stochastic model for bipolar cell orientation on cyclically deformed substrates.
• To investigate the role of peak-to-peak axial strain and strain thresholds in cell reorientation.
• To compare model predictions with experimental observations of human melanocyte behavior.

Main Methods:

• Developed a stochastic model based on cell strain thresholds and avoidance behavior.
• Conducted stretch experiments on human melanocytes using cyclic stretching (1 Hz) at 0, 4, 8, and 12% amplitudes.
• Analyzed cell orientation distributions using the Kolmogorov-Smirnov test.

Main Results:

• The model successfully predicted cell orientation distributions for 4% and 8% stretches (p=0.70 and p=0.71, respectively).
• Determined the mean strain threshold of 3.5% and standard deviation of 1.0% for the cell population.
• Experimental data supported the model's hypotheses regarding cell avoidance of high strain directions.

Conclusions:

• The developed stochastic model accurately describes bipolar cell reorientation in response to substrate deformation.
• Cells exhibit a strain threshold, randomly orienting within acceptable strain limits.
• This study provides a quantitative framework for understanding mechanotransduction in cell orientation.