Related Experiment Video

Updated: May 31, 2025

"Phagosome Closure Assay" to Visualize Phagosome Formation in Three Dimensions Using Total Internal Reflection Fluorescent Microscopy TIRFM
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"Phagosome Closure Assay" to Visualize Phagosome Formation in Three Dimensions Using Total Internal Reflection Fluorescent Microscopy TIRFM

Published on: August 26, 2016

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Force-bearing phagocytic adhesion rings mediate the phagocytosis of surface-bound particles

Subhankar Kundu1, Kaushik Pal2, Arghajit Pyne1

  • 1Hoxworth Center, College of Medicine, University of Cincinnati, Cincinnati, OH, USA.

Nature Communications
|January 24, 2025
PubMed

Insights

Macrophages detach adhered particles using unique phagocytic adhesion rings (PARs). These β₂ integrin structures constrict and pinch off particles, crucial for efficient phagocytosis across species.

Area of Science:

  • Cell biology
  • Immunology
  • Biophysics

Background:

  • Micro-particles, including pathogens, adhere strongly to host cells.
  • The mechanism by which macrophages detach these surface-bound particles during phagocytosis is not well understood.

Purpose of the Study:

  • To elucidate the mechanism of particle detachment by macrophages during phagocytosis.
  • To identify the cellular structures and molecular players involved in detaching surface-bound particles.

Main Methods:

  • Live-cell imaging of macrophages interacting with micro-particles.
  • Immunofluorescence microscopy to visualize actin and integrin dynamics.
  • Functional assays to assess the role of adhesion structures in particle internalization.

Main Results:

  • Macrophages form unique β₂ integrin-mediated adhesion structures, termed phagocytic adhesion rings (PARs), encircling surface-bound particles.
  • PARs support ring-shaped actin constriction that pinches particles from the substrate.
  • Integrins within PARs sustain tension, critical for efficient detachment and phagocytosis of surface-bound particles.
  • PAR formation is conserved across different macrophage types (mouse, human, fish) and particle types (microbeads, E. coli).

Conclusions:

  • Phagocytic adhesion rings (PARs) represent a novel mechanism for macrophages to detach and internalize surface-bound particles.
  • PARs utilize β₂ integrin-mediated adhesion and actin dynamics to overcome particle adhesion to substrates.
  • This conserved mechanism highlights the adaptability of macrophages in engulfing challenging targets.

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