Extracellular vesicles from Distinct Histoplasma capsulatum Strains Modulate Phagocyte Function and Promote Fungal...

Area of Science:

• Mycology
• Immunology
• Cell Biology

Background:

• Fungal extracellular vesicles (EVs) are key mediators of fungal pathogenesis.
• EVs transport diverse molecules, including virulence factors and antigens.
• Histoplasma capsulatum EVs modulate host immune responses.

Purpose of the Study:

• Investigate the effects of EVs from distinct Histoplasma capsulatum strains on immune cells.
• Determine how H. capsulatum EVs influence macrophage and dendritic cell functions.
• Elucidate the role of EVs in host-pathogen interactions and fungal persistence.

Main Methods:

• Isolated EVs from H. capsulatum strains G-217B and G-184A.
• Treated bone marrow-derived macrophages (BMDMs) and dendritic cells (BMDCs) with H. capsulatum EVs.
• Assessed cytokine production (IL-6, IL-10), nitric oxide (NO) production, metabolic activity, and phagocytosis.

Main Results:

• H. capsulatum EVs were internalized by BMDMs and BMDCs, eliciting distinct responses.
• EVs increased IL-6 production in BMDMs and both IL-6 and IL-10 in BMDCs.
• EVs reduced phagocyte metabolic activity and enhanced fungal growth, suggesting a self-stimulatory mechanism.

Conclusions:

• H. capsulatum EVs significantly modulate phagocyte function, influencing host-pathogen interactions.
• EVs play a role in immune evasion and may contribute to fungal virulence and persistence.
• These findings highlight EVs as critical components in Histoplasma pathogenesis.