Two-component macrophage model for active phagocytosis with pseudopod formation

Area of Science:

• Cell Biology
• Biophysics
• Computational Biology

Background:

• Macrophage phagocytosis is essential for immunity, tissue repair, and homeostasis.
• The process involves complex cell shape changes, cytoskeletal reorganization, and receptor-ligand interactions under mechanical forces.
• Existing models lack a comprehensive approach to the mechanical aspects of phagocytosis with cytoskeletal dynamics.

Purpose of the Study:

• To develop a novel coarse-grained mesoscopic model for simulating the mechanical process of phagocytosis.
• To investigate the role of cytoskeletal rearrangement and cell membrane dynamics during macrophage phagocytosis.
• To explore the mechanisms of pseudopod formation and phagocytic cup development.

Main Methods:

• A coarse-grained mesoscopic model integrating a fluid-like cell membrane and a cytoskeletal network was developed.
• The model simulates actin filament growth, cytoskeleton disassembly/reconstruction, and membrane area modification.
• Computational methods like micropipette aspiration were used to analyze mechanical properties.

Main Results:

• The model successfully simulates active phagocytosis through pseudopod formation and phagocytic cup generation.
• Dynamic changes in the cytoskeleton enable pseudopod extension and target engulfment.
• A novel algorithm prevents membrane rupture by managing surface area during phagocytosis.
• The model allows investigation of macrophage mechanical properties like bending modulus and cortical tension.

Conclusions:

• The developed model provides a powerful tool for studying the mechanics of macrophage phagocytosis at the cytoskeletal level.
• It elucidates the dynamic interplay between the macrophage cytoskeleton, cell membrane, and target particles.
• This research offers insights into the physical mechanisms underlying immune cell function and tissue repair.