Transcriptomic response of Cryptococcus neoformans to ecologically relevant nitrogen concentrations
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PROVIDER: PRJNA694029 | ENA |
REPOSITORIES: ENA
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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 causes meningoencephalitis and is an increasing human health threat. C. neoformans is neurotropic, and persists in the cerebrospinal fluid (CSF) of the mammalian host during infection. In order to survive in the host, pathogenic fungi must procure nutrients such as carbon and nitrogen. To enhance our understanding of nutrient acquisition during infection by Cryptococcus species, we examined utilization of nitrogen sources available in CSF. We screened for growth and capsule production of 817 global environmental and clinical isolates on various sources of nitrogen. Capsule production was assessed using ammonium and urea in the presence or absence of benomyl to determine the relationship of urea exposure to capsule production. Since urea is metabolized to ammonia and CO2 (a known signal for capsule induction), we examined urea metabolism mutants for their response to urea regarding capsule production. Non-preferred nitrogen sources were found to greatly affect capsule production in pathogenic species of Cryptococcus. Urea induced the greatest magnitude of capsule production. Capsule induction by urea was greater in Cryptococcus gattii strains than in C. neoformans strains. In addition, both environmental and clinical strains grew robustly on uric acid, casamino acids, creatinine, and asparagine as sole nitrogen sources. While substantial growth on nitrate was not apparent at day 3, growth was apparent by day 6 for all serotypes.
2013-09-25 | GSE46829 | GEO
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:To identify the genome-wide transcriptional changes that occur throughout germination of C. neoformans spores, we conducted a time-course microarray experiment spanning six timepoints to generate a temporal expression pattern for each known gene. Spores were placed in rich medium and allowed to germinate for 10 hours, when they start to replicate as yeast. Each time point was flash frozen in liquid nitrogen and RNA was harvested for each time point at the same time. Microarray hybridizations were conducted in a reference pool design, where each time point was mixed together in equal amounts to make a reference pool sample. Then each time point was hybrdized against the reference pool. Characterization of the genes and pathways that are regulated during germination of this ubiquitous fungal pathogen will allow us to better understand how infectious spores resume vegetative growth, a process that likely is critical for interaction between C. neoformans and a host.
2014-07-31 | GSE53912 | GEO
Project description:Cryptococcus neoformans is an opportunistic environmental fungal pathogen that at its peak epidemic levels caused an estimated million cases of cryptococcal meningitis per year worldwide. This yeast can adapt to various external (trees, soil, and/or bird excreta) and internal environments (intracellular microenvironments of phagocytes and/or free-living in host tissues/fluids). The genetic basic for this adaptation is not fully characterized and primarily relies on a single reference C. neoformans strain. To uncover genes important for yeast infection and disease progression we have compared the gene expression from multiple strains of different lineages (VNI and VNBI) and sources (environment and clinic) under diverse conditions. Here, we used RNA sequencing to assess the transcriptional profiles of seven C. neoformans isolates grown in five representative in vitro, environmental, and in vivo conditions. We characterized gene expression differences between isolates from two of the major lineages of this species, VNI and VNBI, between these conditions. Comparing isolates from these two lineages, we find that genes showing lineage specific expression are enriched in sub-telomeric regions and in lineage specific gene clusters. The major gene expression differences common in all conditions are involved in the utilization of different sugar and nitrogen sources. Comparing gene expression in macrophages and cerebrospinal fluid (CSF) also revealed several specific pathways down-regulated in CSF including lipid and carbohydrate metabolism, and valine, leucine and isoleucine degradation, which may reflect the usage of host nutrients during growth in the mammalian subarachnoid space compared to MP. In summary, our study provides the widest view to date of the transcriptome variation of C. neoformans across natural strains and provides insights into genes important for major in vitro and in vivo growth stages.
2019-09-05 | GSE136879 | 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:Cryptococcus neoformans causes meningoencephalitis and is an increasing human health threat. C. neoformans is neurotropic, and persists in the cerebrospinal fluid (CSF) of the mammalian host during infection. In order to survive in the host, pathogenic fungi must procure nutrients such as carbon and nitrogen. To enhance our understanding of nutrient acquisition during infection by Cryptococcus species, we examined utilization of nitrogen sources available in CSF. We screened for growth and capsule production of 817 global environmental and clinical isolates on various sources of nitrogen. Capsule production was assessed using ammonium and urea in the presence or absence of benomyl to determine the relationship of urea exposure to capsule production. Since urea is metabolized to ammonia and CO2 (a known signal for capsule induction), we examined urea metabolism mutants for their response to urea regarding capsule production. Non-preferred nitrogen sources were found to greatly affect capsule production in pathogenic species of Cryptococcus. Urea induced the greatest magnitude of capsule production. Capsule induction by urea was greater in Cryptococcus gattii strains than in C. neoformans strains. In addition, both environmental and clinical strains grew robustly on uric acid, casamino acids, creatinine, and asparagine as sole nitrogen sources. While substantial growth on nitrate was not apparent at day 3, growth was apparent by day 6 for all serotypes. In this study, transcription profiles of urea pathway mutants (ure1 and amt1/2) and WT Cryptococcus neoformans strains were compared in a dye-swap experiment following 1hr exposure to proline or proline + urea (.25g/L).
2013-09-25 | E-GEOD-46829 | biostudies-arrayexpress
Project description:The target of rapamycin (TOR) pathway is an evolutionarily conserved signal transduction system that is activated by varying nutrient and environmental signals and governs a plethora of eukaryotic biological processes. Nevertheless, its role in the human fungal pathogen Cryptococcus neoformans remains elusive. In this study, we investigated the TOR pathway by functionally characterizing two Tor-like kinases, Tor1 and Tlk1, in C. neoformans. We successfully deleted TLK1, but not TOR1. TLK1 deletion did not result in any evident in vitro phenotypes, except for a minor role in diamide and polyene resistance, suggesting that Tlk1 is mainly dispensable for the growth of C. neoformans. We further demonstrated that Tor1, but not Tlk1, is essential and the target of rapamycin by constructing and analyzing conditionally regulated strains and sporulation analysis of heterozygous mutants in the diploid strain background. To analyze the functions of Tor1 in more detail, we constructed constitutive TOR1 overexpression strains. Tor1 negatively regulated thermotolerance and the DNA damage response, which are two important virulence factors of C. neoformans. We also found that TOR1 overexpression reduced Mpk1 phosphorylation, which is required for cell wall integrity and thermoresistance, and Rad53 phosphorylation, which governs the DNA damage response pathway. Tor1 is localized to the cytoplasm but enriched in the vacuole membrane. Phosphoproteomics and transcriptomics revealed that Tor1 regulates a variety of biological processes, including metabolic processes, cytoskeleton organization, ribosome biogenesis, autophagy, and stress response. Finally, screening rapamycin-sensitive and -resistant kinase and transcription factor mutants revealed that the TOR pathway may crosstalk with a number of signaling pathways, including the Hog1 pathway. In conclusion, our study demonstrates that a single Tor1 kinase plays a variety of roles in the fungal meningitis pathogen C. neoformans.
2019-10-10 | PXD012983 | 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: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