Avaliação do papel da hipóxia na modulação da parede celular do fungo Paracoccidioides brasiliensis
Data
2021-09-24
Autores
Barros, Yasmin Nascimento de [UNIFESP]
Orientadores
Batista, Wagner Luiz [UNIFESP]
Tipo
Dissertação de mestrado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
Fungos termodimórficos do gênero Paracoccidioides são os agentes etiológicos da paracoccidioidomicose (PCM), uma micose sistêmica com ocorrência na América Latina. A interação entre Paracoccidioides spp. e seu ambiente extracelular, são de grande importância para o sucesso do estabelecimento do fungo no hospedeiro. Embora os fungos patogênicos respondam a diferentes estresses, tais como: altas temperaturas, ROS/RNS, alterações de pH e limitação de macro e micronutrientes, pouco se conhece sobre como os fungos patogênicos humanos respondem à limitação de oxigênio, particularmente quando condições hipóxicas são encontradas no tecido hospedeiro. Neste sentido, o objetivo do trabalho é avaliar a modulação dos componentes da parede celular de Paracoccidioides brasiliensis em respostaa ambientes com baixas concentrações de oxigênio. Os resultados demonstram um aumento viabilidade do P. brasilienses quando incubado a baixas concentrações de oxigênio. Além disso, genes envolvidos na síntese de α-glucana aumentaram ao mesmo tempo que genes relacionados a síntese de β-glucana reduzem sua expressão relativa em resposta a hipóxia. Ensaio de interação entre β-glucana e Dectina-1 por citometria de fluxo demonstrou que em baixas concentrações de oxigênio, há uma redução da interação entre β-glucana e seu receptor. Além disso, Leveduras de P. brasiliensis apresentam uma resistência à fagocitose quando submetido à hipóxia. Em adição, a via de cAMP-PKA não parece estar envolvida na modulação dos componentes de parede celular de leveduras de P. brasiliensis sob baixas concentrações de oxigênio. Por fim, as leveduras submetidas a hipóxia apresentaram uma menor suscetibilidade ao antifúngico fluconazol. Em conjunto, os resultados encontrados nesse trabalho sugerem uma modulação da parede celular do fungo patogênico P. brasiliensis em resposta à hipóxia.
Thermodimorphic fungi of the genus Paracoccidioides are the etiologic agents of paracoccidioidomycosis (PCM), a systemic mycosis occurring in Latin America. The interaction between Paracoccidioides spp. and extracellular environment, have great importance for the successful establishment of the fungus in the host. Although pathogenic fungi respond to different stresses, such as high temperatures, ROS/RNS, pH changes and macro and micronutrient limitations, little is known about how human pathogenic fungi respond to oxygen limitation, particularly when hypoxic conditions are encountered in the host tissue. In this sense, the objective of the work is to evaluate the modulation of the cell wall components of Paracoccidioides brasiliensis in response environments with low concentrations of oxygen. In view of the studies being conducted, the partial results demonstrate an increased viability of P. brasilienses when incubated at low oxygen concentrations. In addition, genes involved in the synthesis of α-glucan increased at the same time that genes related to β-glucan synthesis reduced their relative expression in response to hypoxia. Interaction assay between β-glucan and Dectin-1 by flow cytometry demonstrated that at low oxygen concentrations, there is a reduction in the interaction between β-glucan and its receptores. In addition, P. brasiliensis yeasts show resistance to phagocytosis when submitted to hypoxia. Finally, the cAMP-PKA pathway does not appear to be involved in the modulation of cell wall components of P. brasiliensis yeasts under low oxygen concentrations. Finally, the yeasts submitted to hypoxia showed a lower susceptibility to the antifungal fluconazole. Together, the results found in this work suggest a modulation of the cell wall of the pathogenic fungus P. brasiliensis in response to hypoxia.
Thermodimorphic fungi of the genus Paracoccidioides are the etiologic agents of paracoccidioidomycosis (PCM), a systemic mycosis occurring in Latin America. The interaction between Paracoccidioides spp. and extracellular environment, have great importance for the successful establishment of the fungus in the host. Although pathogenic fungi respond to different stresses, such as high temperatures, ROS/RNS, pH changes and macro and micronutrient limitations, little is known about how human pathogenic fungi respond to oxygen limitation, particularly when hypoxic conditions are encountered in the host tissue. In this sense, the objective of the work is to evaluate the modulation of the cell wall components of Paracoccidioides brasiliensis in response environments with low concentrations of oxygen. In view of the studies being conducted, the partial results demonstrate an increased viability of P. brasilienses when incubated at low oxygen concentrations. In addition, genes involved in the synthesis of α-glucan increased at the same time that genes related to β-glucan synthesis reduced their relative expression in response to hypoxia. Interaction assay between β-glucan and Dectin-1 by flow cytometry demonstrated that at low oxygen concentrations, there is a reduction in the interaction between β-glucan and its receptores. In addition, P. brasiliensis yeasts show resistance to phagocytosis when submitted to hypoxia. Finally, the cAMP-PKA pathway does not appear to be involved in the modulation of cell wall components of P. brasiliensis yeasts under low oxygen concentrations. Finally, the yeasts submitted to hypoxia showed a lower susceptibility to the antifungal fluconazole. Together, the results found in this work suggest a modulation of the cell wall of the pathogenic fungus P. brasiliensis in response to hypoxia.