Figure 6. Effect of CATP decreased expression in an ex vivo and in vivo models of infection.

(A) P. brasiliensis yeast cells were incubated in the presence of human PMNs for 3 hours, at 36 °C, with 5% of CO₂. Then, yeast cells survival was determined by enumeration of viable CFUs (black bar). Later on, human PMNs were treated with DPI (blue bar) in order to inhibit NADPH-oxidase. Next, yeast survival was determined during the interaction of P. brasiliensis with human PMNs treated with DPI. (B) Virulence of PbCATP-aRNA isolate in an experimental murine model of infection. CFUs recovered from lungs of mice intranasally inoculated with 1.5×10⁶ yeast cells obtained from PbWT, PbEV, and PbCATP-aRNA strains. Mice were euthanized at 12 days post-infection, their organs were harvested and the fungal burden in lung tissue was determined. No significant differences between the PbWT and PbEV strains were found. Asterisks indicate significant differences (p < 0.05) from animals infected with PbWT and PbEV as compared to PbCATP-aRNA strains determined by Student’s t test. (C) Expression of CAT isoforms in yeast cells from PbWT obtained after interaction with PMNs (ex vivo) and in yeast cells recovered from lung tissues (in vivo). Bars represent the fold changes (in vivo compared to ex vivo gene expression) for PbCATA, PbCATB and PbCATP genes, determined through RT-qPCR assay and normalized with the housekeeping gene β-tubulin.