Cryptococcus neoformans
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ABSTRACT:
PROVIDER: PRJNA139121 | ENA |
REPOSITORIES: ENA
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Project description:Cryptococcus spp. are environmental fungi that first must adapt to the host environment before they can cause life-threatening meningitis in immunocompromised patients. Host CO2 concentrations are 100-fold higher than the external environment and strains unable to grow at host CO2 concentrations are not pathogenic. Using a genetic screening and transcriptional profiling approach, we found that the TOR pathway is critical for C. neoformans adaptation to host CO2 partly through Ypk1-dependent remodeling of phosphatidylserine asymmetry at the plasma membrane. We also identified a C. neoformans ABC/PDR transporter (PDR9) that is highly expressed in CO2-sensitive environmental strains, suppresses CO2-induced phosphatidylserine remodeling, and increases susceptibility to host concentrations of CO2. Interestingly, regulation of plasma membrane lipid asymmetry by the TOR-Ypk1 axis is distinct in C. neoformans compared to S. cerevisiae. Finally, host CO2 concentrations suppress the C. neoformans pathways that respond to host temperature (Mpk1) and pH (Rim101), indicating that host adaptation requires a stringent balance among distinct stress responses.
2023-10-24 | GSE241788 | GEO
Project description:We measured protein translation (by ribosome profiling) and RNA levels (by polyA-enriched RNA-seq) in Cryptococcus neoformans strain H99 and Cryptococcus neoformans strain JEC21. This is the first transcriptome-wide map of translation in this species complex.
2019-06-22 | GSE133125 | GEO
Project description:Thermotolerance, a key factor essential for the virulence of pathogenic fungi including Cryptococcus neoformans, remains largely unexplored in terms of its underlying mechanism. In this study, our findings demonstrate that Set3C, a widely distributed and conserved histone deacetylase complex, is required for thermotolerance in Cryptococcus neoformans. Specifically, the deletion of the core subunit Set302, responsible for the integrity of the complex, results in a significant reduction in the growth ability under high stress and the viability at extreme temperature. Moreover, the absence of Set302 leads to a decrease in the production of capsule and melanin. Transcriptomics analysis revealed that Set302 regulates a large number of genes compared to normal condition, and their expression is responsive to heat stress. Notably, we observed that Set302 positively influences the expression of genes related to ubiquitin-proteasome system (UPS) at high temperature. Using GFP-α-synuclein overexpression model, we observed a pronounced accumulation of misfolded proteins under heat stress, consequently inhibiting the thermotolerance of Cryptococcus neoformans. Furthermore, the loss of Set302 exacerbates this inhibition of thermotolerance. Interestingly, set302∆ strain exhibits a similar phenotype under proteasome stress as it does under high temperature. We also found that set302∆ strain displayed significantly reduced pathogenicity and colonization ability compared to the wild-type strain in the murine infection model. Collectively, our findings indicate that Set302 modulates the degradation of misfolded proteins through the UPS pathway, thereby affecting the thermotolerance and pathogenicity of Cryptococcus neoformans.
2023-09-05 | GSE242109 | GEO
Project description:Cryptococcus neoformans interactions with murine macrophages are critical for disease. In this project we analyzed fungal proteins which were co-purified with murine host proteins after interaction. H99 C. neoformans was opsonized with mAb 18B7 and addedd to murine macrophages. Then murine cells were lysed and cell extracts submitted to proteomics.
2023-03-11 | PXD024951 | Pride
Project description:We investigated the effects of the hypoxia-mimetic CoCl2 on the gene expression of pathogenic fungus Cryptococcus neoformans. Keywords: compound treatment design
2009-05-01 | GSE11390 | GEO
Project description:C. neoformans is an opportunistic human pathogen whose polysaccharide capsule anchored to the cell wall is critical for virulence. Biogenesis of both cell wall and capsule relies on the secretory pathway. Protein secretion begins with protein translocation across the endoplasmic reticulum (ER) membrane through a highly conserved channel formed by three proteins, Sec61, Sbh1, and Sss1. Sbh1 is most divergent and contains multiple phosphorylation sites which may allow it to control entry into the secretory pathway in a regulated, species- and protein-specific manner. We show here that in contrast to S. cerevisiae, C. neoformans lacking SBH1 are barely temperature-sensitive, but that absence of SBH1 causes a cell-wall defect in both species. Comparison of the proteomes of wildtype and Δsbh1 C. neoformans revealed a small set of secretory and transmembrane proteins whose expression under infection-like conditions was upregulated in wildtype, but not in the Δsbh1 mutant. These proteins are mostly involved in cell-wall biogenesis. We found that adhesion to macrophages was compromised in the Δsbh1 strain and in mice, the C. neoformans Δsbh1 mutant was virtually avirulent. We conclude that upon contact with the host Sbh1 controls entry of virulencefactors into the secretory pathway of Cryptococcus neoformans.
2023-01-27 | PXD013894 | Pride
Project description:The opportunistic fungal pathogen Cryptococcus neoformans must adapt to the mammalian environment to establish an infection. Proteins facilitating adaptation to novel environments, such as chaperones, may be required for virulence. In this study, we identified a novel mitochondrial co-chaperone, Mrj1, necessary for virulence in C. neoformans. The mrj1∆ and J-domain inactivated mutants had general growth defects, and were deficient in two major virulence factors, thermotolerance and capsule elaboration. The latter phenotype was associated with cell wall changes and increased capsular polysaccharide shedding. Accordingly, the mrj1∆ mutant was avirulent in a murine model of cryptococcosis. Mrj1 has a mitochondrial localization and co-immunoprecipitated with Qcr2, a core component of complex III of the ETC (Electron Transport Chain). The mrj1 mutants were deficient in mitochondrial functions including growth on alternative carbon sources, growth without iron, and mitochondrial polarization. They were also insensitive to complex III inhibitors and hypersensitive to an alternative oxidase (AOX) inhibitor suggesting that Mrj1 functions in respiration. In support of this conclusion, mrj1 mutants also had elevated basal oxygen consumption rates which were completely abolished by the addition of the AOX inhibitor, confirming that Mrj1 is required for mitochondrial respiration through complexes III and IV. Furthermore, inhibition of complex III phenocopied the capsule and cell wall defects of the mrj1 mutants. Taken together, these results indicate that Mrj1 is required for normal mitochondrial respiration, a key aspect of adaptation to the host environment and virulence.
2020-06-12 | PXD013659 | Pride
Project description:We examine the transcriptomic response of Cryptococcus neoformans to two different ecologically relevant nitrogen concentrations. Our data revealed that low nitrogen conditions modulate the expression of numerous virulence genes in C. neoformans. Among these were, CTR4 and CGP1, which showed highly significant modulation under low nitrogen conditions. Furthermore, data analysis revealed the upregulation of antifungal tolerance-related genes in low nitrogen conditions, including genes involved in ergosterol biosynthetic processes and cell wall integrity. Overall, our findings provide insight into the survival of C. neoformans in nitrogen-poor ecological niches and suggest that pre-adaptation to these conditions may influence the pathobiology of this yeast.
2021-01-23 | GSE165294 | GEO
Project description:Cryptococcus neoformans is an invasive human fungal pathogen, which causes pneumonia and meningoencephalitis in both healthy and immunodeficient individuals, resulting 181,100 deaths each year. Studies have demonstrated that copper detoxification machineries play critical functions in modulating C. neoformans fitness and pathogenicity in the host lung tissue. Pulmonary C. neoformans infection provokes the generation of toxic copper bombardment, which in return activate detoxification process in fungal cells. However, the molecular mechanism on how Cu inhibits C. neoformans in proliferation remains unclear. Here, using Cu detoxification gene knockout strains we demonstrated that exogenous Cu ions inhibit cell growth of the metallothionein mutant, which was significantly rescue when supplementing with the ROS scavenger, N-acetylcysteine. To future characterize the molecular mechanism of C. neoformans response to Cu toxicity, we employ iTRAQ with LC-MS/MS analysis, in the presence of exogenous Cu or NAC. Our data showed that an increased Cu level repressed expression of factors involved in protein translation but activates expression of important players in ubiquitin-degradation process. We proposed that the downregulation of protein synthesis and the upregulation of protein degradation were the main strategy of Cu toxicity. The metallothionein mutant showed a higher ubiquitination level under Cu treatment. In addition, MG132 could partially restore the Cu toxicity effect on metallothionein mutant. These results shed new light on the Cu antifungal mechanisms from proteomic profile.
2021-02-09 | PXD024098 |
Project description:Cryptococcus neoformans, an environmental opportunistic human fungal pathogen, is a causative agent for acute pulmonary infection and meningoencephalitis. Understanding the host’s response to C. neoformans infection is critical for developing effective treatment. Even though some have elucidated the host response at the transcriptome level, little is known about how it modulates its defense machinery through the proteome mechanism or how protein posttranslational modification responds to the infection. In this work, we employed a Cryptococcus murine infection model and mass spectrometry to systematically determine the proteome and acetylome statuses of two primary organs (lung and brain) in the early stage of infection. To extensively analyze the host response, we compared and integrated the proteome data to the transcriptome results. We demonstrated a significant overlap between two data sets. Critical genes, including genes involved in phagosome, lysosome, or osteoblast differentiation and platelet activation are significantly altered in protein and gene expression during infection. In the acetylome analysis, we demonstrated that lung and brain tissues differentially regulate protein acetylation during infection. The three primary groups of proteins altered in acetylation status are histones, proteins involved in glucose and fatty acid metabolism, and proteins from the immune system. These analyses provide an integrative regulation network of the host responding to C. neoformans and shed new light on understanding the host’s regulation mechanism when responding to C. neoformans.
2020-04-21 | PXD016614 | Pride