Yeast-amoeba interaction influences murine cryptococcosis

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 exopolysaccharide content and influences the progression of cryptococcal infection. (c) 2023 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Automated summary

The virulence of Cryptococcus spp. can be regulated by the interaction with abiotic and biotic factors in the natural environment. This study evaluated the impact of prior interaction between highly virulent Cryptococcus gattii strain R265 and Acanthamoeba castellanii on the progression of cryptococcosis. The results showed that the interaction between yeast and amoeba altered yeast phenotype, polysaccharide secretion, and oxidative stress tolerance, thus influencing the progression of cryptococcal infection.