Interaction of Cryptococcus neoformans extracellular vesicles with the cell wall

Area of Science:

• Mycology
• Cell Biology
• Biochemistry

Background:

• Cryptococcus neoformans generates extracellular vesicles (EVs) carrying virulence factors.
• The mechanism of fungal EV release through the cell wall remains largely unknown.
• Understanding EV biogenesis and release is crucial for fungal pathogenesis research.

Purpose of the Study:

• To elucidate the ultrastructural morphology of vesicle release from C. neoformans.
• To investigate the mechanisms of vesicle transit through the fungal cell wall.
• To analyze vesicle size and protein composition.

Main Methods:

• Electron microscopy was employed to visualize vesicle-cell wall interactions.
• Melanized C. neoformans cells were used to trap and study vesicles in the cell wall.
• Proteomic analysis was performed on different vesicle populations.

Main Results:

• Distinct single and multiple vesicle-leaving events were observed, suggesting different origins (plasma membrane vs. multivesicular bodies).
• Vesicle size varied based on the release mechanism.
• Proteomic analysis identified numerous new EV-associated proteins, but minimal differences between size-based vesicle batches.

Conclusions:

• Fungal extracellular vesicles are produced via multiple biogenesis pathways.
• Vesicles traverse the cell wall to reach the extracellular space.
• EV populations exhibit continuous variation in size and protein content, challenging discrete categorization.