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

Huang, Lawrence ; Helmke, Brian

In: Cellular and Molecular Bioengineering, 2011, vol. 4, no. 2, p. 205-219

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    Titre
    • A Semi-Automatic Method for Image Analysis of Edge Dynamics in Living Cells
    Auteur
    • Huang, Lawrence. Department of Biomedical Engineering, University of Virginia, P.O. Box 800759, 22908-0759, Charlottesville, VA, USA
    • Helmke, Brian. Department of Biomedical Engineering, University of Virginia, P.O. Box 800759, 22908-0759, Charlottesville, VA, USA
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • Cellular and Molecular Bioengineering, 2011, vol. 4, no. 2, p. 205-219. Springer US; http://www.springer-ny.com
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:318433
    Summary
    Spatial asymmetry of actin edge ruffling contributes to the process of cell polarization and directional migration, but mechanisms by which external cues control actin polymerization near cell edges remain unclear. We designed a quantitative image analysis strategy to measure the spatiotemporal distribution of actin edge ruffling. Time-lapse images of endothelial cells (ECs) expressing mRFP-actin were segmented using an active contour method. In intensity line profiles oriented normal to the cell edge, peak detection identified the angular distribution of polymerized actin within 1μm of the cell edge, which was localized to lamellipodia and edge ruffles. Edge features associated with filopodia and peripheral stress fibers were removed. Circular statistical analysis enabled detection of cell polarity, indicated by a unimodal distribution of edge ruffles. To demonstrate the approach, we detected a rapid, nondirectional increase in edge ruffling in serum-stimulated ECs and a change in constitutive ruffling orientation in quiescent, nonpolarized ECs. Error analysis using simulated test images demonstrate robustness of the method to variations in image noise levels, edge ruffle arc length, and edge intensity gradient. These quantitative measurements of edge ruffling dynamics enable investigation at the cellular length scale of the underlying molecular mechanisms regulating actin assembly and cell polarization