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Time-lapse 3D Imaging of Phagocytosis by Mouse Macrophages
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Micromechanics of filopodia mediated capture of pathogens by macrophages

L Vonna1, A Wiedemann, M Aepfelbacher

  • 1Institut de Chimie des Surfaces et Interfaces, 15, rue Jean Starcky, BP2478, 68057 Mulhouse Cedex, France. laurent.vonna@uha.fr

European Biophysics Journal : EBJ
|December 13, 2006
PubMed

Insights

Filopodia, cell structures, can generate significant retraction forces to capture and detach pathogens. This study reveals their mechanical role in the initial steps of phagocytosis by macrophages.

Area of Science:

  • Cell Biology
  • Biophysics
  • Immunology

Background:

  • Filopodia are crucial for cell functions but their mechanical properties are underexplored.
  • Understanding filopodia's mechanical role is key to comprehending cellular interactions with pathogens.

Purpose of the Study:

  • To investigate the mechanical forces generated by filopodia during pathogen capture.
  • To explore the role of filopodia in the initial stages of phagocytosis using bacterial mimetics.

Main Methods:

  • Magnetic microbeads coated with invasin (a bacterial protein) were used as pathogen mimetics.
  • J774 mouse macrophages with long filopodia were utilized for experiments.
  • The retraction dynamics of filopodia upon bead adhesion were analyzed using bead motion tracking.

Main Results:

  • Specific adhesion of beads to filopodia tips triggered retraction.
  • Filopodia generated substantial retraction forces over large distances (>10 micrometers).
  • The study quantified the minimal force developed by filopodia during this process.

Conclusions:

  • Thin filopodia can exert surprisingly large retraction forces.
  • Filopodia act as effective mechanical tools for detaching adhered pathogens.
  • This highlights the mechanical significance of filopodia in host-pathogen interactions.

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