Conservation of Intracellular Pathogenic Strategy among Distantly Related Cryptococcal Species

Abstract

The genus includes several species pathogenic for humans. Until recently, the two major pathogenic species were recognized to be and We compared the interaction of murine macrophages with three species complex strains (WM179, R265, and WM161, representing molecular types VGI, VGIIa, and VGIII, respectively) and one species complex strain (H99, molecular type VNI) to ascertain similarities and differences in the yeast intracellular pathogenic strategy. The parameters analyzed included nonlytic exocytosis frequency, phagolysosomal pH, intracellular capsular growth, phagolysosomal membrane permeabilization, and macrophage transcriptional response, assessed using time-lapse microscopy, fluorescence microscopy, flow cytometry, and gene expression microarray analysis. The most striking result was that the intracellular pathogenic strategies of and species complex strains were qualitatively similar, despite the species having separated an estimated 100 million years ago. Macrophages exhibited a leaky phagolysosomal membrane phenotype and nonlytic exocytosis when infected with either or Conservation of the intracellular strategy among species that separated long ago suggests that it is ancient and possibly maintained by similar selection pressures through eons.

Cryptococcus neoformans and Cryptococcus gattii clinical isolates from Thailand display diverse phenotypic interactions with macrophages

“…Graphs depict mean ± SD and are representative of 3 experiments with 3 to 5 mice per group. Significance was determined by one-way ANOVA with Tukey's post hoc analysis * p <0.05, ** p <0.01 and *** p <0.001. similar [27]. Larger studies including strains from other geographical regions with different types of macrophage should be carried out to support our findings.…”

Macrophages use a bet-hedging strategy for antimicrobial activity in phagolysosomal acidification

“…Phagolysosomal pH was measured using ratiometric fluorescence imaging involving the use of pH-sensitive probe Oregon Green 488 as described in prior studies (15). The pH values analyzed here were collected in part during prior studies of C. neoformans-macrophage interactions (14)(15)(16). Briefly, Oregon Green 488 was first conjugated to monoclonal antibody (mAb) 18B7, which binds C. neoformans capsular polysaccharide, using an Oregon Green 488 Protein Labeling Kit (Molecular Probes).…”

“…Prior studies of C. neoformans phagosomal acidification measured great variation in the pH of individual phagolysosomes (14)(15)(16). The pH of cryptococcal phagolysosomes is affected by several microbial factors, including urease expression (15), phagosomal membrane integrity (14), and the presence of the cryptococcal capsule with glucuronic acid residues (17).…”

Cryptococcal Traits Mediating Adherence to Biotic and Abiotic Surfaces

“…Since severe fungal infections have become more common with the widespread use of indwelling medical devices, broad-spectrum antibiotics, and increased immunocompromised patient populations, future research on fungal adhesins during biofilm development would be highly significant to the medical field. Strikingly, a recent study performed by our group demonstrate that C. neoformans and C. gattii species complex strains conserved the same intracellular pathogenic strategies despite having separated around 100 million year ago, suggesting that these mechanisms are possible maintained by similar selective forces through ages [ 159 ]. Hence, particular focus on expanding our understanding of the “atypical” mechanisms related to cryptococcal adherence could be potentially valuable in therapy.…”