Unraveling the mechanism of action of the PepGAT peptide against Candida albicans through proteomics approaches

Candida albicans is a major opportunistic human pathogen, frequently implicated in infections with increasing antifungal resistance. As such, the search for new therapeutic alternatives is essential. Therefore, synthetic antimicrobial peptides (SAMPs) have emerged as promising alternatives because resistance development against these molecules appears to occur less frequently than against many conventional antimicrobial drugs. Here, the mechanisms of action of the chitinase-derived synthetic peptide PepGAT, which is bioinspired by the chitinase of Arabidopsis thaliana, were evaluated against C. albicans. Proteomic analysis, enzymatic activity assays, ergosterol interaction studies, and membrane permeability assessments were performed to provide insights into how PepGAT affects C. albicans. Proteomic analysis revealed that PepGAT alters the protein profile of C. albicans cells, disrupting several key pathways involved in cell development, lipid metabolism, and drug resistance. Moreover, PepGAT decreased superoxide dismutase (SOD) activity while increasing catalase (CAT) activity, suggesting an impact on the cellular redox system. Additionally, PepGAT inhibits ergosterol biosynthesis, potentially leading to the formation of membrane pores with a size of at least 6 kDa, as suggested by fluorescence microscopy. Altogether, these findings indicate that PepGAT exhibits multiple mechanisms of action against C. albicans, highlighting its potential as an alternative antifungal agent.