Aspergillus fumigatus activates thrombocytes by secretion of soluble compounds

Area of Science:

• Immunology
• Hematology
• Mycology

Background:

• Invasive aspergillosis involves complex host-pathogen interactions.
• The role of platelets (thrombocytes) in fungal infections is not fully understood.
• Platelets may contribute to both defense and pathology during Aspergillus infections.

Purpose of the Study:

• To investigate whether Aspergillus fumigatus secretes factors that influence platelet activity.
• To determine the mechanisms and consequences of fungus-induced platelet activation.

Main Methods:

• Platelets were incubated with Aspergillus fumigatus culture supernatant.
• Platelet activation was assessed by measuring granule release, membrane changes, aggregation, and microparticle formation.
• In vivo studies involved infecting mice with A. fumigatus and analyzing thrombocyte activation.
• Stimulating components in the supernatant were identified.

Main Results:

• Fungal culture supernatant potently stimulated platelets in a time- and dose-dependent manner.
• Stimulation induced platelet degranulation, aggregation, and microparticle formation.
• Infected mice exhibited higher platelet activation levels compared to controls.
• A fungal serine protease and the mycotoxin gliotoxin were identified as key activators.
• Activated platelets demonstrated enhanced antifungal activity, inhibiting fungal growth.

Conclusions:

• Aspergillus fumigatus secretes factors that activate platelets, influencing their function.
• Platelet activation by fungal components supports antifungal immunity but may also promote inflammation and thrombosis.
• Platelet activation could be a potential diagnostic parameter for invasive aspergillosis.