The outcome of phagocytic cell division with infectious cargo depends on single phagosome formation

Area of Science:

• Cell Biology
• Immunology
• Microbiology

Background:

• Macrophages are crucial phagocytic cells involved in host defense.
• Certain microbes, such as Cryptococcus yeasts, can survive and replicate within macrophages.
• Understanding how intracellular microbial cargo is distributed after host cell division is critical for pathogen survival and host immunity.

Purpose of the Study:

• To investigate the post-mitotic distribution of intracellular microbial cargo within host cells.
• To compare the distribution of Cryptococcus yeasts with inert polystyrene beads.
• To elucidate the mechanisms governing unequal cargo distribution and its implications for host-pathogen interactions.

Main Methods:

• Utilized macrophage-like cells for experimental analysis.
• Quantified the distribution of intracellular Cryptococcus yeasts and polystyrene beads post-mitosis.
• Employed a stochastic model to compare experimental data with theoretical predictions.

Main Results:

• Polystyrene beads exhibited stochastic, random distribution between daughter cells.
• Cryptococcus yeasts displayed unequal post-mitotic distribution, with preferential sorting to one daughter cell.
• Phagosomal fusion was identified as a mechanism reducing intracellular particle load and contributing to unequal distribution.

Conclusions:

• Post-mitotic intracellular particle distribution is generally stochastic but can be biased by microbial or host factors.
• Unequal cargo distribution in this system favored the microbe, potentially enhancing host cell exocytosis.
• The post-mitotic distribution of infectious cargo represents a novel factor influencing the outcome of intracellular pathogen interactions.