RESUMO
Cryptococcus gattii and Cryptococcus neoformans are the main etiological agents of cryptococcosis, an invasive mycosis treated with amphotericin B, 5-fluorocytosine, and fluconazole. This limited arsenal is toxic and is associated with antifungal resistance. Cryptococcosis and malaria pathogens are eukaryotic organisms that have a high incidence in Sub-Saharan Africa. The antimalarials (ATMs) halofantrine (HAL) and amodiaquine (AQ) block Plasmodium heme polymerase, and artesunate (ART) induces oxidative stress. Considering that Cryptococcus spp. is susceptible to reactive oxygen species and that iron is essential for metabolism, the repurposing of ATMs for treating cryptococcosis was tested. ATMs reduced fungal growth, induced oxidative and nitrosative stresses, and altered ergosterol content, melanin production, and polysaccharide capsule size in C. neoformans and C. gattii, revealing a dynamic effect on fungal physiology. A comprehensive chemical-genetic analysis using two mutant libraries demonstrated that the deletion of genes involved in synthesizing components of the plasma membrane and cell wall, and oxidative stress responses are essential for fungal susceptibility to ATMs. Interestingly, the amphotericin B (AMB) fungicidal concentrations were â¼10 times lower when combined with ATMs, demonstrating a synergistic interaction. Further, the combinations showed reduced toxicity to murine macrophages. Finally, HAL+AMB and AQ+AMB efficiently reduced lethality and fungal burden in the lungs and brain in murine cryptococcosis. These findings provide perspectives for further studies with ATMs against cryptococcosis and other fungal infections.
Assuntos
Antimaláricos , Criptococose , Cryptococcus gattii , Cryptococcus neoformans , Animais , Camundongos , Anfotericina B/farmacologia , Anfotericina B/uso terapêutico , Antifúngicos/farmacologia , Antifúngicos/uso terapêutico , Antifúngicos/metabolismo , Antimaláricos/farmacologia , Antimaláricos/uso terapêutico , Antimaláricos/metabolismo , Criptococose/tratamento farmacológico , Criptococose/microbiologia , Fluconazol/farmacologia , Fluconazol/uso terapêutico , Testes de Sensibilidade MicrobianaRESUMO
The phenotypic plasticity of Cryptococcus neoformans is widely studied and demonstrated in vitro, but its influence on pathogenicity remains unclear. In this study, we investigated the dynamics of cryptococcal cell and transcriptional remodeling during pulmonary infection in a murine model. We showed that in Cryptococcus neoformans, cell size reduction (cell body ≤ 3 µm) is important for initial adaptation during infection. This change was associated with reproductive fitness and tissue invasion. Subsequently, the fungus develops mechanisms aimed at resistance to the host's immune response, which is determinant for virulence. We investigated the transcriptional changes involved in this cellular remodeling and found an upregulation of transcripts related to ribosome biogenesis at the beginning (6 h) of infection and a later (10 days) upregulation of transcripts involved in the inositol pathway, energy production, and the proteasome. Consistent with a role for the proteasome, we found that its inhibition delayed cell remodeling during infection with the H99 strain. Altogether, these results further our understanding of the infection biology of C. neoformans and provide perspectives to support therapeutic and diagnostic targets for cryptococcosis.