RESUMO
The increasing prevalence of Candida parapsilosis as a causative agent of fungal infections underscores the need to comprehensively understand its virulence factors. Secreted aspartic proteases (Saps) play a significant role in adhesion events, promoting biofilm formation, causing tissue damage and evading the host's immune response. In C. parapsilosis, three Saps have been identified: Sapp1, Sapp2 and Sapp3. The present study investigates the production dynamics of Sapp1 and Sapp2 across 10 clinical isolates of C. parapsilosis using various approaches. Each fungal isolate demonstrated the capability to utilize bovine serum albumin (BSA) as the sole nitrogen source, as evidenced by its degradation in a cell-free culture medium, forming low molecular mass polypeptides. Interestingly, the degradation of different proteinaceous substrates, such as BSA, human serum albumin (HSA), gelatin and hemoglobin, was typically isolate-dependent. Notably, higher proteolysis of HSA compared to BSA, gelatin and hemoglobin was observed. A quantitative assay revealed that the cleavage of a peptide fluorogenic substrate (cathepsin D) was isolate-specific, ranging from 44.15 to 270.61 fluorescence arbitrary units (FAU), with a mean proteolysis of 150.7 FAU. The presence of both Sapp1 and Sapp2 antigens on the cell surface of these fungal isolates was confirmed through immunological detection employing specific anti-Sapp1 and anti-Sapp2 antibodies. The surface levels of Sapp1 were consistently higher, up to fourfold, compared to Sapp2. Similarly, higher levels of Sapp1 than Sapp2 were detected in fungal secretions. This study provides insights into the dynamic expression and regulation of Sapps in C. parapsilosis, highlighting a known virulence factor that is considered a potential target for drug development against this increasingly prominent pathogen.
The fungal pathogen Candida parapsilosis can secrete aspartic proteases (Sapps) as part of its arsenal of virulence factors. We demonstrated that Sapps were able to cleave key host proteins, and the production of Sapp1 and Sapp2 antigens was typically dependent on the fungal isolate when grown in both planktonic- and biofilm-forming cells.
Assuntos
Ácido Aspártico Proteases , Candida parapsilosis , Candida parapsilosis/enzimologia , Candida parapsilosis/genética , Humanos , Ácido Aspártico Proteases/metabolismo , Ácido Aspártico Proteases/genética , Fatores de Virulência/metabolismo , Soroalbumina Bovina , Proteólise , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/genética , Candidíase/microbiologia , Meios de Cultura/química , Catepsina D/metabolismo , Proteases Aspárticas SecretedasRESUMO
Abstract INTRODUCTION: Candida parapsilosis complex species differ from each other with regard to their prevalence and virulence. METHODS: The hydrolytic enzyme activity, biofilm production, and adhesion to epithelial cells were analyzed in 87 C. parapsilosis complex strains. RESULTS: Among the studied isolates, 97.7%, 63.2%, and 82.8% exhibited very strong proteinase, esterase, and hemolysin activity, respectively. All the C. parapsilosis complex isolates produced biofilms and presented an average adherence of 96.0 yeasts/100 epithelial cells. CONCLUSIONS: Our results show that Candida parapsilosis complex isolates showed different levels of enzyme activity, biofilm production, and adhesion to epithelial cells.