The antimicrobial peptide, psacotheasin induces reactive oxygen species and triggers apoptosis in Candida albicans

Previously, the antimicrobial effects and membrane-active action of psacotheasin in Candida albicans were investigated. In this study, we have further found that a series of characteristic cellular changes of apoptosis in C. albicans can be induced by the accumulation of intracellular reactive oxygen species, specifically hydroxyl radicals, the well-known important regulators of apoptosis. Cells treated with psacotheasin showed diagnostic markers in yeast apoptosis at early stages: phosphatidylserine externalization from the inner to the outer membrane surface, visualized by Annexin V-staining; mitochondrial membrane depolarization, observed by DiOC6(3) staining; and increase of metacaspase activity, measured using the CaspACE FITC-VAD-FMK. Moreover, DNA fragmentation and condensation also revealed apoptotic phenomena at late stages through the TUNEL assay staining and DAPI staining, respectively. Taken together, our findings suggest that psacotheasin possess an antifungal property in C. albicans via apoptosis as another mode of action.

Research highlights
► Psacotheasin increases total intracellular ROS levels in C. albicans.
► Phosphatidylserine externalization by psacotheasin in C. albicans.
► Psacotheasin induces collapse of ΔΨm and increases the activation of metacaspase in C. albicans.
► Psacotheasin induces late apoptotic phenotype in C. albicans.