A Semi-Automatic Method for Image Analysis of Edge Dynamics in Living Cells

Area of Science:

• Cell Biology
• Biophysics
• Quantitative Imaging

Background:

• Actin edge ruffling is crucial for cell polarization and directional migration.
• The precise mechanisms by which external cues regulate actin polymerization at cell edges are not fully understood.

Purpose of the Study:

• To develop and validate a quantitative image analysis strategy for measuring the spatiotemporal distribution of actin edge ruffling.
• To investigate the role of actin polymerization dynamics in cell polarization and migration.

Main Methods:

• Utilized time-lapse imaging of endothelial cells (ECs) expressing mRFP-actin.
• Employed active contour segmentation and intensity line profile analysis to quantify polymerized actin near cell edges.
• Applied circular statistical analysis to detect cell polarity based on edge ruffle distribution.

Main Results:

• Successfully detected rapid, nondirectional increases in edge ruffling in serum-stimulated ECs.
• Observed changes in constitutive ruffling orientation in quiescent, nonpolarized ECs.
• Demonstrated method robustness through error analysis on simulated images.

Conclusions:

• The developed quantitative method accurately measures actin edge ruffling dynamics at the cellular length scale.
• This approach facilitates the investigation of molecular mechanisms underlying actin assembly and cell polarization.
• Provides a robust tool for studying cell migration and polarity.