Hydrogen peroxide-induced secondary necrosis in conidia of Aspergillus fumigatus.

Aspergillus fumigatus conidia have been linked to severe aspergillosis in immunocompromised patients. Recently, the cytotoxic effect of secondary metabolites from A. fumigatus conidia was reported. In the present work, a methodology used to detect cell death markers in fungal hyphae was adapted to study conidia cell death. Additionally, the mechanism of H2O2-induced cell death was studied in A. fumigatus conidia for the first time. Data presented in this work reveal that the H2O2-induced conidial cell death was associated with a marked increase of TUNEL- and PI-positive cells. It is therefore suggested that conidia cell death occurs in a dose-dependent manner through a secondary necrosis mechanism. The knowledge of conidia cell death machinery may provide insights into the molecular mechanism of conidia-mediated toxicity to the respiratory tract and may pave the way for improved therapeutic approaches against A. fumigatus conidia-mediated diseases.