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Published on: June 22, 2019
Yeast-amoeba interaction influences murine cryptococcosis
Jessica Helen Dos Santos Carvalho1, Jeana Karen Castro Nascimento1, Kassia Gabriela Vieira Silva1
1Laboratório de Biologia Molecular de Microrganismos Patogênicos, Universidade CEUMA, São Luís, Maranhão, Brazil.
Abstract:
The virulence of Cryptococcus spp. is modulated in the natural environment through interaction with abiotic and biotic factors, and this can occasionally have implications for the progression of cryptococcosis in mammals. Hence, we evaluated whether the prior interaction of highly virulent Cryptococcus gattii strain R265 with Acanthamoeba castellanii influenced the progression of cryptococcosis. The influence of the capsule on endocytosis was evaluated using amoeba and yeast morphometrics. Mice were intratracheally infected with yeast re-isolated from the amoeba (Interaction), yeast without prior contact with the amoeba (Non-Interaction), or sterile phosphate-buffered saline (SHAM). Morbidity signs and symptoms were monitored during the survival curve, while cytokine and fungal burden measurements and histopathological analysis were performed on the 10th day post infection. Morbidity and mortality parameters in experimental cryptococcosis were influenced by the prior interaction of yeast with amoeba, which led to phenotypic changes in the cryptococcal cells, polysaccharide secretion, and their tolerance to oxidative stress. Our results suggest that a prior yeast-amoeba interaction modulates yeast virulence, which is associated with a greater tolerance to oxidative stress related to the exo-polysaccharide content and influences the progression of cryptococcal infection.
Insights
Prior interaction between Cryptococcus gattii and Acanthamoeba castellanii enhances fungal virulence. This interaction increases yeast oxidative stress tolerance and impacts cryptococcosis progression in mice.
Area of Science:
- Mycology
- Pathogen-Host Interactions
- Immunology
Background:
- Cryptococcus spp. virulence is influenced by environmental interactions.
- Cryptococcosis progression in mammals can be affected by these interactions.
- The role of environmental factors in modulating fungal virulence is not fully understood.
Purpose of the Study:
- To investigate if prior interaction with Acanthamoeba castellanii influences the virulence of Cryptococcus gattii strain R265.
- To assess the impact of yeast-amoeba interaction on the progression of experimental cryptococcosis.
Main Methods:
- Cryptococcus gattii strain R265 was co-cultured with Acanthamoeba castellanii.
- Mice were infected intratracheally with either interacted or non-interacted yeast.
- Survival, fungal burden, cytokine levels, and histopathology were analyzed.
Main Results:
- Yeast-amoeba interaction led to phenotypic changes in Cryptococcus gattii.
- The interacted yeast exhibited increased polysaccharide secretion and tolerance to oxidative stress.
- Morbidity and mortality parameters were significantly influenced by the prior yeast-amoeba interaction.
Conclusions:
- Prior interaction with Acanthamoeba castellanii modulates Cryptococcus gattii virulence.
- Enhanced oxidative stress tolerance, linked to exopolysaccharide content, contributes to increased virulence.
- Yeast-amoeba interactions represent a significant factor influencing the pathogenesis of cryptococcosis.
