Assuntos
DNA Ribossômico/genética , Piedra/terapia , Pele/microbiologia , Trichosporon/patogenicidade , Tricosporonose/microbiologia , Tricosporonose/terapia , Animais , Humanos , Técnicas de Tipagem Micológica/métodos , Piedra/diagnóstico , Piedra/microbiologia , Trichosporon/classificação , Tricosporonose/diagnóstico , LevedurasRESUMO
Aspergillus fumigatus is an opportunistic pathogenic fungus able to infect immunocompromised patients, eventually causing disseminated infections that are difficult to control and lead to high mortality rates. It is important to understand how the signaling pathways that regulate these factors involved in virulence are orchestrated. Protein phosphatases are central to numerous signal transduction pathways. Here, we characterize the A. fumigatus protein phosphatase 2A SitA, the Saccharomyces cerevisiae Sit4p homologue. The sitA gene is not an essential gene, and we were able to construct an A. fumigatus null mutant. The ΔsitA strain had decreased MpkA phosphorylation levels, was more sensitive to cell wall-damaging agents, had increased ß-(1,3)-glucan and chitin, was impaired in biofilm formation, and had decreased protein kinase C activity. The ΔsitA strain is more sensitive to several metals and ions, such as MnCl2, CaCl2, and LiCl, but it is more resistant to ZnSO4. The ΔsitA strain was avirulent in a murine model of invasive pulmonary aspergillosis and induces an augmented tumor necrosis factor alpha (TNF-α) response in mouse macrophages. These results stress the importance of A. fumigatus SitA as a possible modulator of PkcA/MpkA activity and its involvement in the cell wall integrity pathway.
Assuntos
Aspergillus fumigatus/metabolismo , Biofilmes/crescimento & desenvolvimento , Proteínas de Transporte de Cátions/metabolismo , Adesão Celular/fisiologia , Parede Celular/metabolismo , Monoéster Fosfórico Hidrolases/metabolismo , Virulência/fisiologia , Animais , Quitina/metabolismo , Modelos Animais de Doenças , Feminino , Proteínas Fúngicas/metabolismo , Aspergilose Pulmonar Invasiva/metabolismo , Aspergilose Pulmonar Invasiva/microbiologia , Pneumopatias Fúngicas/metabolismo , Pneumopatias Fúngicas/microbiologia , Macrófagos/microbiologia , Camundongos , Camundongos Endogâmicos BALB C , Transdução de Sinais/fisiologia , Fator de Necrose Tumoral alfa/metabolismoRESUMO
The present study developed Galleria mellonella and murine infection models for the study of Trichosporon infections. The utility of the developed animal models was demonstrated through the assessment of virulence and antifungal efficacy for 7 clinical isolates of Trichosporon asahii, T. asteroides and T. inkin. The susceptibility of the Trichosporon isolates to several common antifungal drugs was tested in vitro using the broth microdilution and the E-test methods. The E-test method depicted a lower minimal inhibitory concentration (MIC) for amphotericin and a slightly higher MIC for caspofungin, while MICs observed for the azoles were different but comparable between both methods. All three Trichosporon species established infection in both the G. mellonella and immunosuppressed murine models. Species and strain dependent differences were observed in both the G. mellonella and murine models. T. asahii was demonstrated to be more virulent than the other 2 species in both animal hosts. Significant differences in virulence were observed between strains for T. asteroides in the murine model. In both animal models, fluconazole and voriconazole were able to improve the survival of the animals compared to the untreated control groups infected with any of the 3 Trichosporon species. In G. mellonella, amphotericin was not able to reduce mortality in any of the 3 species. In contrast, amphotericin was able to reduce murine mortality in the T. asahii or T. inkin models, respectively. Hence, the developed animal infection models can be directly applicable to the future deeper investigation of the molecular determinants of Trichosporon virulence and antifungal resistance.