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Ortiz SC, Hull CM. Biogenesis, germination, and pathogenesis of Cryptococcus spores. Microbiol Mol Biol Rev 2024; 88:e0019623. [PMID: 38440970 PMCID: PMC10966950 DOI: 10.1128/mmbr.00196-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2024] Open
Abstract
SUMMARYSpores are primary infectious propagules for the majority of human fungal pathogens; however, relatively little is known about their fundamental biology. One strategy to address this deficiency has been to develop the basidiospores of Cryptococcus into a model for pathogenic spore biology. Here, we provide an update on the state of the field with a comprehensive review of the data generated from the study of Cryptococcus basidiospores from their formation (sporulation) and differentiation (germination) to their roles in pathogenesis. Importantly, we provide support for the presence of basidiospores in nature, define the key characteristics that distinguish basidiospores from yeast cells, and clarify their likely roles as infectious particles. This review is intended to demonstrate the importance of basidiospores in the field of Cryptococcus research and provide a solid foundation from which researchers who wish to study sexual spores in any fungal system can launch their studies.
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Affiliation(s)
- Sébastien C. Ortiz
- Department of Biomolecular Chemistry, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Christina M. Hull
- Department of Biomolecular Chemistry, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
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2
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Milner DS, Galindo LJ, Irwin NAT, Richards TA. Transporter Proteins as Ecological Assets and Features of Microbial Eukaryotic Pangenomes. Annu Rev Microbiol 2023; 77:45-66. [PMID: 36944262 DOI: 10.1146/annurev-micro-032421-115538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
Abstract
Here we review two connected themes in evolutionary microbiology: (a) the nature of gene repertoire variation within species groups (pangenomes) and (b) the concept of metabolite transporters as accessory proteins capable of providing niche-defining "bolt-on" phenotypes. We discuss the need for improved sampling and understanding of pangenome variation in eukaryotic microbes. We then review the factors that shape the repertoire of accessory genes within pangenomes. As part of this discussion, we outline how gene duplication is a key factor in both eukaryotic pangenome variation and transporter gene family evolution. We go on to outline how, through functional characterization of transporter-encoding genes, in combination with analyses of how transporter genes are gained and lost from accessory genomes, we can reveal much about the niche range, the ecology, and the evolution of virulence of microbes. We advocate for the coordinated systematic study of eukaryotic pangenomes through genome sequencing and the functional analysis of genes found within the accessory gene repertoire.
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Affiliation(s)
- David S Milner
- Department of Biology, University of Oxford, Oxford, United Kingdom;
| | | | - Nicholas A T Irwin
- Department of Biology, University of Oxford, Oxford, United Kingdom;
- Merton College, University of Oxford, Oxford, United Kingdom
| | - Thomas A Richards
- Department of Biology, University of Oxford, Oxford, United Kingdom;
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3
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Han L, Wu Y, Xiong S, Liu T. Ubiquitin Degradation of the AICAR Transformylase/IMP Cyclohydrolase Ade16 Regulates the Sexual Reproduction of Cryptococcus neoformans. J Fungi (Basel) 2023; 9:699. [PMID: 37504688 PMCID: PMC10381356 DOI: 10.3390/jof9070699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 06/17/2023] [Accepted: 06/21/2023] [Indexed: 07/29/2023] Open
Abstract
F-box protein is a key protein of the SCF E3 ubiquitin ligase complex, responsible for substrate recognition and degradation through specific interactions. Previous studies have shown that F-box proteins play crucial roles in Cryptococcus sexual reproduction. However, the molecular mechanism by which F-box proteins regulate sexual reproduction in C. neoformans is unclear. In the study, we discovered the AICAR transformylase/IMP cyclohydrolase Ade16 as a substrate of Fbp1. Through protein interaction and stability experiments, we demonstrated that Ade16 is a substrate for Fbp1. To examine the role of ADE16 in C. neoformans, we constructed the iADE16 strains and ADE16OE strains to analyze the function of Ade16. Our results revealed that the iADE16 strains had a smaller capsule and showed growth defects under NaCl, while the ADE16OE strains were sensitive to SDS but not to Congo red, which is consistent with the stress phenotype of the fbp1Δ strains, indicating that the intracellular protein expression level after ADE16 overexpression was similar to that after FBP1 deletion. Interestingly, although iADE16 strains can produce basidiospores normally, ADE16OE strains can produce mating mycelia but not basidiospores after mating, which is consistent with the fbp1Δmutant strains, suggesting that Fbp1 is likely to regulate the sexual reproduction of C. neoformans through the modulation of Ade16. A fungal nuclei development assay showed that the nuclei of the ADE16OE strains failed to fuse in the bilateral mating, indicating that Ade16 plays a crucial role in the regulation of meiosis during mating. In summary, our findings have revealed a new determinant factor involved in fungal development related to the post-translational regulation of AICAR transformylase/IMP cyclohydrolase.
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Affiliation(s)
- Liantao Han
- State Key Laboratory of Resource Insects, Southwest University Medical Research Institute, Chongqing 400715, China
| | - Yujuan Wu
- State Key Laboratory of Resource Insects, Southwest University Medical Research Institute, Chongqing 400715, China
| | - Sichu Xiong
- State Key Laboratory of Resource Insects, Southwest University Medical Research Institute, Chongqing 400715, China
| | - Tongbao Liu
- State Key Laboratory of Resource Insects, Southwest University Medical Research Institute, Chongqing 400715, China
- Jinfeng Laboratory, Chongqing 401329, China
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4
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Sephton-Clark P, Tenor JL, Toffaletti DL, Meyers N, Giamberardino C, Molloy SF, Palmucci JR, Chan A, Chikaonda T, Heyderman R, Hosseinipour M, Kalata N, Kanyama C, Kukacha C, Lupiya D, Mwandumba HC, Harrison T, Bicanic T, Perfect JR, Cuomo CA. Genomic Variation across a Clinical Cryptococcus Population Linked to Disease Outcome. mBio 2022; 13:e0262622. [PMID: 36354332 PMCID: PMC9765290 DOI: 10.1128/mbio.02626-22] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 10/13/2022] [Indexed: 11/12/2022] Open
Abstract
Cryptococcus neoformans is the causative agent of cryptococcosis, a disease with poor patient outcomes that accounts for approximately 180,000 deaths each year. Patient outcomes may be impacted by the underlying genetics of the infecting isolate; however, our current understanding of how genetic diversity contributes to clinical outcomes is limited. Here, we leverage clinical, in vitro growth and genomic data for 284 C. neoformans isolates to identify clinically relevant pathogen variants within a population of clinical isolates from patients with human immunodeficiency virus (HIV)-associated cryptococcosis in Malawi. Through a genome-wide association study (GWAS) approach, we identify variants associated with the fungal burden and the growth rate. We also find both small and large-scale variation, including aneuploidy, associated with alternate growth phenotypes, which may impact the course of infection. Genes impacted by these variants are involved in transcriptional regulation, signal transduction, glycosylation, sugar transport, and glycolysis. We show that growth within the central nervous system (CNS) is reliant upon glycolysis in an animal model and likely impacts patient mortality, as the CNS yeast burden likely modulates patient outcome. Additionally, we find that genes with roles in sugar transport are enriched in regions under selection in specific lineages of this clinical population. Further, we demonstrate that genomic variants in two genes identified by GWAS impact virulence in animal models. Our approach identifies links between the genetic variation in C. neoformans and clinically relevant phenotypes and animal model pathogenesis, thereby shedding light on specific survival mechanisms within the CNS and identifying the pathways involved in yeast persistence. IMPORTANCE Infection outcomes for cryptococcosis, most commonly caused by C. neoformans, are influenced by host immune responses as well as by host and pathogen genetics. Infecting yeast isolates are genetically diverse; however, we lack a deep understanding of how this diversity impacts patient outcomes. To better understand both clinical isolate diversity and how diversity contributes to infection outcomes, we utilize a large collection of clinical C. neoformans samples that were isolated from patients enrolled in a clinical trial across 3 hospitals in Malawi. By combining whole-genome sequence data, clinical data, and in vitro growth data, we utilize genome-wide association approaches to examine the genetic basis of virulence. Genes with significant associations display virulence attributes in both murine and rabbit models, demonstrating that our approach can identify potential links between genetic variants and patho-biologically significant phenotypes.
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Affiliation(s)
- Poppy Sephton-Clark
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Jennifer L. Tenor
- Division of Infectious Diseases, Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA
| | - Dena L. Toffaletti
- Division of Infectious Diseases, Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA
| | - Nancy Meyers
- Division of Infectious Diseases, Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA
| | - Charles Giamberardino
- Division of Infectious Diseases, Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA
| | - Síle F. Molloy
- Centre for Global Health, Institute of Infection and Immunity, St George's University of London, London, United Kingdom
- Clinical Academic Group in Infection, St George's University Hospital, London, United Kingdom
| | - Julia R. Palmucci
- Division of Infectious Diseases, Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA
| | - Adrienne Chan
- Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
| | - Tarsizio Chikaonda
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Robert Heyderman
- Division of Infection and Immunity, University College London, London, United Kingdom
| | - Mina Hosseinipour
- UNC Project Malawi, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Newton Kalata
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Cecilia Kanyama
- UNC Project Malawi, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Christopher Kukacha
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Duncan Lupiya
- Tisungane Clinic, Zomba Central Hospital, Zomba, Malawi
| | - Henry C. Mwandumba
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Thomas Harrison
- Centre for Global Health, Institute of Infection and Immunity, St George's University of London, London, United Kingdom
- Clinical Academic Group in Infection, St George's University Hospital, London, United Kingdom
| | - Tihana Bicanic
- Centre for Global Health, Institute of Infection and Immunity, St George's University of London, London, United Kingdom
- Clinical Academic Group in Infection, St George's University Hospital, London, United Kingdom
| | - John R. Perfect
- Division of Infectious Diseases, Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA
| | - Christina A. Cuomo
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
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5
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Han LT, Wu YJ, Liu TB. The F-Box Protein Fbp1 Regulates Virulence of Cryptococcus neoformans Through the Putative Zinc-Binding Protein Zbp1. Front Cell Infect Microbiol 2022; 11:794661. [PMID: 35024357 PMCID: PMC8744115 DOI: 10.3389/fcimb.2021.794661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 12/06/2021] [Indexed: 11/13/2022] Open
Abstract
The ubiquitin-proteasome system (UPS) is the major protein turnover mechanism that plays an important role in regulating various cellular functions. F-box proteins are the key proteins of the UPS, responsible for the specific recognition and ubiquitination of downstream targets. Our previous studies showed that the F-box protein Fbp1 plays an essential role in the virulence of C. neoformans. However, the molecular mechanism of Fbp1 regulating the virulence of C. neoformans is still unclear. In this study, we analyzed the potential Fbp1 substrates using an iTRAQ-based proteomic approach and identified the zinc-binding protein Zbp1 as a substrate of Fbp1. Protein interaction and stability assays showed that Zbp1 interacts with Fbp1 and is a downstream target of Fbp1. Ubiquitination analysis in vivo showed that the ubiquitination of Zbp1 is dependent on Fbp1 in C. neoformans. Subcellular localization analysis revealed that the Zbp1 protein was localized in the nucleus of C. neoformans cells. In addition, both deletion and overexpression of the ZBP1 gene led to the reduced capsule size, while overexpression has a more significant impact on capsule size reduction. Fungal virulence assays showed that although the zbp1Δ mutants are virulent, virulence was significantly attenuated in the ZBP1 overexpression strains. Fungal load assay showed that the fungal burdens recovered from the mouse lungs decreased gradually after infection, while no yeast cells were recovered from the brains and spleens of the mice infected by ZBP1 overexpression strains. Thus, our results revealed a new determinant of fungal virulence involving the post-translational regulation of a zinc-binding protein.
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Affiliation(s)
- Lian-Tao Han
- State Key Laboratory of Silkworm Genomic Biology, Southwest University, Chongqing, China.,Chongqing Key Laboratory of Microsporidia Infection and Control, Southwest University, Chongqing, China
| | - Yu-Juan Wu
- State Key Laboratory of Silkworm Genomic Biology, Southwest University, Chongqing, China.,Chongqing Key Laboratory of Microsporidia Infection and Control, Southwest University, Chongqing, China
| | - Tong-Bao Liu
- State Key Laboratory of Silkworm Genomic Biology, Southwest University, Chongqing, China.,Chongqing Key Laboratory of Microsporidia Infection and Control, Southwest University, Chongqing, China.,Medical Research Institute, Southwest University, Chongqing, China
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6
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Emergence and evolution of virulence in human pathogenic fungi. Trends Microbiol 2022; 30:693-704. [DOI: 10.1016/j.tim.2021.12.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 12/21/2021] [Accepted: 12/21/2021] [Indexed: 12/23/2022]
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7
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Inositol Metabolism Regulates Capsule Structure and Virulence in the Human Pathogen Cryptococcus neoformans. mBio 2021; 12:e0279021. [PMID: 34724824 PMCID: PMC8561382 DOI: 10.1128/mbio.02790-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The environmental yeast Cryptococcus neoformans is the most common cause of deadly fungal meningitis in primarily immunocompromised populations. A number of factors contribute to cryptococcal pathogenesis. Among them, inositol utilization has been shown to promote C. neoformans development in nature and invasion of central nervous system during dissemination. The mechanisms of the inositol regulation of fungal virulence remain incompletely understood. In this study, we analyzed inositol-induced capsule growth and the contribution of a unique inositol catabolic pathway in fungal development and virulence. We found that genes involved in the inositol catabolic pathway are highly induced by inositol, and they are also highly expressed in the cerebrospinal fluid of patients with meningoencephalitis. This pathway in C. neoformans contains three genes encoding myo-inositol oxygenases that convert myo-inositol into d-glucuronic acid, a substrate of the pentose phosphate cycle and a component of the polysaccharide capsule. Our mutagenesis analysis demonstrates that inositol catabolism is required for C. neoformans virulence and deletion mutants of myo-inositol oxygenases result in altered capsule growth as well as the polysaccharide structure, including O-acetylation. Our study indicates that the ability to utilize the abundant inositol in the brain may contribute to fungal pathogenesis in this neurotropic fungal pathogen. IMPORTANCE The human pathogen Cryptococcus neoformans is the leading cause of fungal meningitis in primarily immunocompromised populations. Understanding how this environmental organism adapts to the human host to cause deadly infection will guide our development of novel disease control strategies. Our recent studies revealed that inositol utilization by the fungus promotes C. neoformans development in nature and invasion of the central nervous system during infection. The mechanisms of the inositol regulation in fungal virulence remain incompletely understood. In this study, we found that C. neoformans has three genes encoding myo-inositol oxygenase, a key enzyme in the inositol catabolic pathway. Expression of these genes is highly induced by inositol, and they are highly expressed in the cerebrospinal fluid of patients with meningoencephalitis. Our mutagenesis analysis indeed demonstrates that inositol catabolism is required for C. neoformans virulence by altering the growth and structure of polysaccharide capsule, a major virulence factor. Considering the abundance of free inositol and inositol-related metabolites in the brain, our study reveals an important mechanism of host inositol-mediated fungal pathogenesis for this neurotropic fungal pathogen.
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8
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Gröhs Ferrareze PA, Maufrais C, Silva Araujo Streit R, Priest SJ, Cuomo CA, Heitman J, Staats CC, Janbon G. Application of an optimized annotation pipeline to the Cryptococcus deuterogattii genome reveals dynamic primary metabolic gene clusters and genomic impact of RNAi loss. G3-GENES GENOMES GENETICS 2021; 11:6080769. [PMID: 33585873 PMCID: PMC8022950 DOI: 10.1093/g3journal/jkaa070] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 12/24/2020] [Indexed: 12/15/2022]
Abstract
Evaluating the quality of a de novo annotation of a complex fungal genome based on RNA-seq data remains a challenge. In this study, we sequentially optimized a Cufflinks-CodingQuary-based bioinformatics pipeline fed with RNA-seq data using the manually annotated model pathogenic yeasts Cryptococcus neoformans and Cryptococcus deneoformans as test cases. Our results show that the quality of the annotation is sensitive to the quantity of RNA-seq data used and that the best quality is obtained with 5–10 million reads per RNA-seq replicate. We also showed that the number of introns predicted is an excellent a priori indicator of the quality of the final de novo annotation. We then used this pipeline to annotate the genome of the RNAi-deficient species Cryptococcus deuterogattii strain R265 using RNA-seq data. Dynamic transcriptome analysis revealed that intron retention is more prominent in C. deuterogattii than in the other RNAi-proficient species C. neoformans and C. deneoformans. In contrast, we observed that antisense transcription was not higher in C. deuterogattii than in the two other Cryptococcus species. Comparative gene content analysis identified 21 clusters enriched in transcription factors and transporters that have been lost. Interestingly, analysis of the subtelomeric regions in these three annotated species identified a similar gene enrichment, reminiscent of the structure of primary metabolic clusters. Our data suggest that there is active exchange between subtelomeric regions, and that other chromosomal regions might participate in adaptive diversification of Cryptococcus metabolite assimilation potential.
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Affiliation(s)
- Patrícia Aline Gröhs Ferrareze
- Département de Mycologie, Institut Pasteur, Unité Biologie des ARN des Pathogènes Fongiques, F-75015 Paris, France.,Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre 15005, Brazil
| | - Corinne Maufrais
- Département de Mycologie, Institut Pasteur, Unité Biologie des ARN des Pathogènes Fongiques, F-75015 Paris, France.,Département Biologie Computationnelle, Institut Pasteur, HUB Bioinformatique et Biostatistique, C3BI, USR 3756 IP CNRS, F-75015 Paris, France
| | - Rodrigo Silva Araujo Streit
- Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre 15005, Brazil
| | - Shelby J Priest
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Christina A Cuomo
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Charley Christian Staats
- Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre 15005, Brazil
| | - Guilhem Janbon
- Département de Mycologie, Institut Pasteur, Unité Biologie des ARN des Pathogènes Fongiques, F-75015 Paris, France
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9
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Johns LE, Goldman GH, Ries LN, Brown NA. Nutrient sensing and acquisition in fungi: mechanisms promoting pathogenesis in plant and human hosts. FUNGAL BIOL REV 2021. [DOI: 10.1016/j.fbr.2021.01.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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10
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Jung WH, Sánchez-León E, Kronstad JW. Coordinated regulation of iron metabolism in Cryptococcus neoformans by GATA and CCAAT transcription factors: connections with virulence. Curr Genet 2021; 67:583-593. [PMID: 33760942 DOI: 10.1007/s00294-021-01172-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 03/01/2021] [Accepted: 03/03/2021] [Indexed: 10/21/2022]
Abstract
Iron acquisition is critical for pathogenic fungi to adapt to and survive within the host environment. However, to same extent, the fungi must also avoid the detrimental effects caused by excess iron. The importance of iron has been demonstrated for the physiology and virulence of major fungal pathogens of humans including Aspergillus fumigatus, Candida albicans, and Cryptococcus neoformans. In particular, numerous studies have revealed that aspects of iron acquisition, metabolism, and homeostasis in the fungal pathogens are tightly controlled by conserved transcriptional regulators including a GATA-type iron transcription factor and the CCAAT-binding complex (CBC)/HapX orthologous protein complex. However, the specific downstream regulatory networks are slightly different in each fungus. In addition, roles have been proposed or demonstrated for other factors including monothiol glutaredoxins, BolA-like proteins, and Fe-S cluster incorporation on the GATA-type iron transcription factor and the CBC/HapX orthologous protein complex, although limited information is available. Here we focus on recent work on C. neoformans in the context of an emerging framework for fungal regulation of iron acquisition, metabolism, and homeostasis. Our specific goal is to summarize recent findings on transcriptional networks governed by the iron regulators Cir1 and HapX in C. neoformans.
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Affiliation(s)
- Won Hee Jung
- Department of Systems Biotechnology, Chung-Ang University, Anseong, 17546, Korea.
| | - Eddy Sánchez-León
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada
| | - James W Kronstad
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada.
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11
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Ramos-Figueroa JS, Aamudalapalli HB, Jagdhane RC, Smith J, Palmer DRJ. Preparation and Application of 13C-Labeled myo-Inositol to Identify New Catabolic Products in Inositol Metabolism in Lactobacillus casei. Biochemistry 2020; 59:2974-2985. [PMID: 32786400 DOI: 10.1021/acs.biochem.0c00539] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
myo-Inositol (mI) is widely distributed in all domains of life and is important for several cellular functions, including bacterial survival. The enzymes responsible for the bacterial catabolism of mI, encoded in the iol operon, can vary from one organism to another, and these pathways have yet to be fully characterized. We previously identified a new scyllo-inositol dehydrogenase (sIDH) in the iol operon of Lactobacillus casei that can oxidize mI in addition to the natural substrate, scyllo-inositol, but the product of mI oxidation was not determined. Here we report the identification of these metabolites by monitoring the reaction with 13C nuclear magnetic resonance. We prepared all six singly 13C-labeled mI isotopomers through a biocatalytic approach and used these labeled inositols as substrates for sIDH. The use of all six singly labeled mI isotopomers allowed for metabolite characterization without isolation steps. sIDH oxidation of mI produces 1l-5-myo-inosose preferentially, but also two minor products, 1d-chiro-inosose and 1l-chiro-inosose. Together with previous crystal structure data for sIDH, we were able to rationalize the observed oxidation preference. Our relatively simple procedure for the preparation of isotopically labeled mI standards can have broad applications for the study of mI biotransformations.
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Affiliation(s)
| | - Hari Babu Aamudalapalli
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada
| | - Rajendra C Jagdhane
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada
| | - Joseph Smith
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada
| | - David R J Palmer
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada
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12
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Osman M, Stigloher C, Mueller MJ, Waller F. An improved growth medium for enhanced inoculum production of the plant growth-promoting fungus Serendipita indica. PLANT METHODS 2020; 16:39. [PMID: 32190103 PMCID: PMC7076966 DOI: 10.1186/s13007-020-00584-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 03/11/2020] [Indexed: 06/10/2023]
Abstract
BACKGROUND The plant endophytic fungus Serendipita indica colonizes roots of a wide range of plant species and can enhance growth and stress resistance of these plants. Due to its ease of axenic cultivation and its broad host plant range including the model plant Arabidopsis thaliana and numerous crop plants, it is widely used as a model fungus to study beneficial fungus-root interactions. In addition, it was suggested to be utilized for commercial applications, e.g. to enhance yield in barley and other species. To produce inoculum, S. indica is mostly cultivated in a complex Hill-Käfer medium (CM medium), however, growth in this medium is slow, and yield of chlamydospores, which are often used for plant root inoculation, is relatively low. RESULTS We tested and optimized a simple vegetable juice-based medium for an enhanced yield of fungal inoculum. The described vegetable juice (VJ) medium is based on commercially available vegetable juice and is easy to prepare. VJ medium was superior to the currently used CM medium with respect to biomass production in liquid medium and hyphal growth on agar plates. Using solid VJ medium supplemented with sucrose (VJS), a high amount of chlamydospores developed already after 8 days of cultivation, producing significantly more spores than on CM medium. Use of VJ medium is not restricted to S. indica, as it also supported growth of two pathogenic fungi often used in plant pathology experiments: the ascomycete Fusarium graminearum, the causal agent of Fusarium head blight disease on wheat and barley, and Verticillium longisporum, the causal agent of verticillium wilt. CONCLUSIONS The described VJ medium is recommended for streamlined and efficient production of inoculum for the plant endophytic fungus Serendipita indica and might prove superior for the propagation of other fungi for research purposes.
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Affiliation(s)
- Mohamed Osman
- Julius-Von-Sachs Institute of Biosciences, Biocenter, Pharmaceutical Biology, Julius-Maximilians-Universität Würzburg, Julius-von-Sachs-Platz 2, 97082 Würzburg, Germany
| | - Christian Stigloher
- Imaging Core Facility, Theodor-Boveri Institute of Biosciences, Biocenter, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Martin J. Mueller
- Julius-Von-Sachs Institute of Biosciences, Biocenter, Pharmaceutical Biology, Julius-Maximilians-Universität Würzburg, Julius-von-Sachs-Platz 2, 97082 Würzburg, Germany
| | - Frank Waller
- Julius-Von-Sachs Institute of Biosciences, Biocenter, Pharmaceutical Biology, Julius-Maximilians-Universität Würzburg, Julius-von-Sachs-Platz 2, 97082 Würzburg, Germany
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13
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A Mechanosensitive Channel Governs Lipid Flippase-Mediated Echinocandin Resistance in Cryptococcus neoformans. mBio 2019; 10:mBio.01952-19. [PMID: 31822582 PMCID: PMC6904872 DOI: 10.1128/mbio.01952-19] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Echinocandins show fungicidal activity against common invasive mycoses but are ineffective against cryptococcosis. The underlying mechanism for echinocandin resistance in Cryptococcus neoformans remains poorly understood but has been shown to involve Cdc50, the regulatory subunit of lipid flippase. In a forward genetic screen for cdc50Δ suppressor mutations that are caspofungin resistant, we identified Crm1 (caspofungin resistant mutation 1), a homolog of mechanosensitive channel proteins, and showed that crm1Δ restored caspofungin resistance in cdc50Δ cells. Caspofungin-treated cdc50Δ cells exhibited abnormally high intracellular calcium levels ([Ca2+]c) and heightened activation of the calcineurin pathway. Deletion of CRM1 in the cdc50Δ background normalized the abnormally high [Ca2+]c. Cdc50 interacts with Crm1 to maintain cellular calcium homeostasis. Analysis of chitin/chitosan content showed that deleting CRM1 reversed the decreased chitosan production of cdc50Δ cells. Together, these results demonstrate that Cdc50 and Crm1 regulation of the calcineurin pathway and cytoplasmic calcium homeostasis may underlie caspofungin resistance in C. neoformans IMPORTANCE Cryptococcus neoformans is the leading cause of fungal meningitis, accounting for ∼15% of HIV/AIDS-related deaths, but treatment options for cryptococcosis are limited. Echinocandins are the newest fungicidal drug class introduced but are ineffective in treating cryptococcosis. Our previous study identified the lipid flippase subunit Cdc50 as a contributor to echinocandin resistance in C. neoformans Here, we further elucidated the mechanism of Cdc50-mediated caspofungin drug resistance. We discovered that Cdc50 interacts with the mechanosensitive calcium channel protein Crm1 to regulate calcium homeostasis and caspofungin resistance via calcium/calcineurin signaling. These results provide novel insights into echinocandin resistance in this pathogen, which may lead to new treatment options, as well as inform echinocandin resistance mechanisms in other fungal organisms and, hence, advance our understanding of modes of antifungal drug susceptibility and resistance.
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Gerstein AC, Jackson KM, McDonald TR, Wang Y, Lueck BD, Bohjanen S, Smith KD, Akampurira A, Meya DB, Xue C, Boulware DR, Nielsen K. Identification of Pathogen Genomic Differences That Impact Human Immune Response and Disease during Cryptococcus neoformans Infection. mBio 2019; 10:e01440-19. [PMID: 31311883 PMCID: PMC6635531 DOI: 10.1128/mbio.01440-19] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 06/10/2019] [Indexed: 12/18/2022] Open
Abstract
Patient outcomes during infection are due to a complex interplay between the quality of medical care, host immunity factors, and the infecting pathogen's characteristics. To probe the influence of pathogen genotype on human survival, immune response, and other parameters of disease, we examined Cryptococcus neoformans isolates collected during the Cryptococcal Optimal Antiretroviral Therapy (ART) Timing (COAT) Trial in Uganda. We measured human participants' survival, meningitis disease parameters, immunologic phenotypes, and pathogen in vitro growth characteristics. We compared those clinical data to whole-genome sequences from 38 C. neoformans isolates of the most frequently observed sequence type (ST), ST93, in our Ugandan participant population and to sequences from an additional 18 strains of 9 other sequence types representing the known genetic diversity within the Ugandan Cryptococcus clinical isolates. We focused our analyses on 652 polymorphisms that were variable among the ST93 genomes, were not in centromeres or extreme telomeres, and were predicted to have a fitness effect. Logistic regression and principal component analysis identified 40 candidate Cryptococcus genes and 3 hypothetical RNAs associated with human survival, immunologic response, or clinical parameters. We infected mice with 17 available KN99α gene deletion strains for these candidate genes and found that 35% (6/17) directly influenced murine survival. Four of the six gene deletions that impacted murine survival were novel. Such bedside-to-bench translational research identifies important candidate genes for future studies on virulence-associated traits in human Cryptococcus infections.IMPORTANCE Even with the best available care, mortality rates in cryptococcal meningitis range from 20% to 60%. Disease is often due to infection by the fungus Cryptococcus neoformans and involves a complex interaction between the human host and the fungal pathogen. Although previous studies have suggested genetic differences in the pathogen impact human disease, it has proven quite difficult to identify the specific C. neoformans genes that impact the outcome of the human infection. Here, we take advantage of a Ugandan patient cohort infected with closely related C. neoformans strains to examine the role of pathogen genetic variants on several human disease characteristics. Using a pathogen whole-genome sequencing approach, we showed that 40 C. neoformans genes are associated with human disease. Surprisingly, many of these genes are specific to Cryptococcus and have unknown functions. We also show deletion of some of these genes alters disease in a mouse model of infection, confirming their role in disease. These findings are particularly important because they are the first to identify C. neoformans genes associated with human cryptococcal meningitis and lay the foundation for future studies that may lead to new treatment strategies aimed at reducing patient mortality.
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Affiliation(s)
- Aleeza C Gerstein
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Katrina M Jackson
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Tami R McDonald
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Yina Wang
- Public Health Research Institute, Rutgers University, Newark, New Jersey, USA
| | - Benjamin D Lueck
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Sara Bohjanen
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Kyle D Smith
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Andrew Akampurira
- Infectious Diseases Institute and School of Medicine, College of Health Sciences, Makerere University, Kampala, Uganda
| | - David B Meya
- Infectious Diseases Institute and School of Medicine, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Chaoyang Xue
- Public Health Research Institute, Rutgers University, Newark, New Jersey, USA
| | - David R Boulware
- Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Kirsten Nielsen
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota, USA
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15
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Rutherford JC, Bahn YS, van den Berg B, Heitman J, Xue C. Nutrient and Stress Sensing in Pathogenic Yeasts. Front Microbiol 2019; 10:442. [PMID: 30930866 PMCID: PMC6423903 DOI: 10.3389/fmicb.2019.00442] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 02/20/2019] [Indexed: 12/23/2022] Open
Abstract
More than 1.5 million fungal species are estimated to live in vastly different environmental niches. Despite each unique host environment, fungal cells sense certain fundamentally conserved elements, such as nutrients, pheromones and stress, for adaptation to their niches. Sensing these extracellular signals is critical for pathogens to adapt to the hostile host environment and cause disease. Hence, dissecting the complex extracellular signal-sensing mechanisms that aid in this is pivotal and may facilitate the development of new therapeutic approaches to control fungal infections. In this review, we summarize the current knowledge on how two important pathogenic yeasts, Candida albicans and Cryptococcus neoformans, sense nutrient availability, such as carbon sources, amino acids, and ammonium, and different stress signals to regulate their morphogenesis and pathogenicity in comparison with the non-pathogenic model yeast Saccharomyces cerevisiae. The molecular interactions between extracellular signals and their respective sensory systems are described in detail. The potential implication of analyzing nutrient and stress-sensing systems in antifungal drug development is also discussed.
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Affiliation(s)
- Julian C Rutherford
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Yong-Sun Bahn
- Department of Biotechnology, Yonsei University, Seoul, South Korea
| | - Bert van den Berg
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, United States
| | - Chaoyang Xue
- Public Health Research Institute, Rutgers University, Newark, NJ, United States.,Department of Molecular Genetics, Biochemistry and Microbiology, Rutgers University, Newark, NJ, United States
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16
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Konarzewska P, Wang Y, Han GS, Goh KJ, Gao YG, Carman GM, Xue C. Phosphatidylserine synthesis is essential for viability of the human fungal pathogen Cryptococcus neoformans. J Biol Chem 2019; 294:2329-2339. [PMID: 30602568 DOI: 10.1074/jbc.ra118.006738] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 12/28/2018] [Indexed: 11/06/2022] Open
Abstract
Phospholipids are an integral part of the cellular membrane structure and can be produced by a de novo biosynthetic pathway and, alternatively, by the Kennedy pathway. Studies in several yeast species have shown that the phospholipid phosphatidylserine (PS) is synthesized from CDP-diacylglycerol and serine, a route that is different from its synthesis in mammalian cells, involving a base-exchange reaction from preexisting phospholipids. Fungal-specific PS synthesis has been shown to play an important role in fungal virulence and has been proposed as an attractive drug target. However, PS synthase, which catalyzes this reaction, has not been studied in the human fungal pathogen Cryptococcus neoformans Here, we identified and characterized the PS synthase homolog (Cn Cho1) in this fungus. Heterologous expression of Cn CHO1 in a Saccharomyces cerevisiae cho1Δ mutant rescued the mutant's growth defect in the absence of ethanolamine supplementation. Moreover, an Sc cho1Δ mutant expressing Cn CHO1 had PS synthase activity, confirming that the Cn CHO1 encodes PS synthase. We also found that PS synthase in C. neoformans is localized to the endoplasmic reticulum and that it is essential for mitochondrial function and cell viability. Of note, its deficiency could not be complemented by ethanolamine or choline supplementation for the synthesis of phosphatidylethanolamine (PE) or phosphatidylcholine (PC) via the Kennedy pathway. These findings improve our understanding of phospholipid synthesis in a pathogenic fungus and indicate that PS synthase may be a useful target for antifungal drugs.
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Affiliation(s)
| | - Yina Wang
- From the Public Health Research Institute and
| | - Gil-Soo Han
- the Rutgers Center for Lipid Research and.,Department of Food Science, Rutgers University, New Brunswick, New Jersey 08901, and
| | - Kwok Jian Goh
- the School of Biological Sciences, Nanyang Technological University, Singapore 117597, Singapore
| | - Yong-Gui Gao
- the School of Biological Sciences, Nanyang Technological University, Singapore 117597, Singapore
| | - George M Carman
- the Rutgers Center for Lipid Research and.,Department of Food Science, Rutgers University, New Brunswick, New Jersey 08901, and
| | - Chaoyang Xue
- From the Public Health Research Institute and .,the Rutgers Center for Lipid Research and.,Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers University, Newark, New Jersey 07103
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17
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The Unfolded Protein Response Pathway in the Yeast Kluyveromyces lactis. A Comparative View among Yeast Species. Cells 2018; 7:cells7080106. [PMID: 30110882 PMCID: PMC6116095 DOI: 10.3390/cells7080106] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 08/04/2018] [Accepted: 08/08/2018] [Indexed: 12/31/2022] Open
Abstract
Eukaryotic cells have evolved signalling pathways that allow adaptation to harmful conditions that disrupt endoplasmic reticulum (ER) homeostasis. When the function of the ER is compromised in a condition known as ER stress, the cell triggers the unfolded protein response (UPR) in order to restore ER homeostasis. Accumulation of misfolded proteins due to stress conditions activates the UPR pathway. In mammalian cells, the UPR is composed of three branches, each containing an ER sensor (PERK, ATF6 and IRE1). However, in yeast species, the only sensor present is the inositol-requiring enzyme Ire1. To cope with unfolded protein accumulation, Ire1 triggers either a transcriptional response mediated by a transcriptional factor that belongs to the bZIP transcription factor family or an mRNA degradation process. In this review, we address the current knowledge of the UPR pathway in several yeast species: Saccharomyces cerevisiae, Schizosaccharomyces pombe, Candida glabrata, Cryptococcus neoformans, and Candida albicans. We also include unpublished data on the UPR pathway of the budding yeast Kluyveromyces lactis. We describe the basic components of the UPR pathway along with similarities and differences in the UPR mechanism that are present in these yeast species.
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18
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Abstract
The kingdom Fungi comprises species that inhabit nearly all ecosystems. Fungi exist as both free-living and symbiotic unicellular and multicellular organisms with diverse morphologies. The genomes of fungi encode genes that enable them to thrive in diverse environments, invade plant and animal cells, and participate in nutrient cycling in terrestrial and aquatic ecosystems. The continuously expanding databases of fungal genome sequences have been generated by individual and large-scale efforts such as Génolevures, Broad Institute's Fungal Genome Initiative, and the 1000 Fungal Genomes Project (http://1000.fungalgenomes.org). These efforts have produced a catalog of fungal genes and genomic organization. The genomic datasets can be utilized to better understand how fungi have adapted to their lifestyles and ecological niches. Large datasets of fungal genomic and transcriptomic data have enabled the use of novel methodologies and improved the study of fungal evolution from a molecular sequence perspective. Combined with microscopes, petri dishes, and woodland forays, genome sequencing supports bioinformatics and comparative genomics approaches as important tools in the study of the biology and evolution of fungi.
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19
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Desjardins CA, Giamberardino C, Sykes SM, Yu CH, Tenor JL, Chen Y, Yang T, Jones AM, Sun S, Haverkamp MR, Heitman J, Litvintseva AP, Perfect JR, Cuomo CA. Population genomics and the evolution of virulence in the fungal pathogen Cryptococcus neoformans. Genome Res 2018; 27:1207-1219. [PMID: 28611159 PMCID: PMC5495072 DOI: 10.1101/gr.218727.116] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 05/01/2017] [Indexed: 12/23/2022]
Abstract
Cryptococcus neoformans is an opportunistic fungal pathogen that causes approximately 625,000 deaths per year from nervous system infections. Here, we leveraged a unique, genetically diverse population of C. neoformans from sub-Saharan Africa, commonly isolated from mopane trees, to determine how selective pressures in the environment coincidentally adapted C. neoformans for human virulence. Genome sequencing and phylogenetic analysis of 387 isolates, representing the global VNI and African VNB lineages, highlighted a deep, nonrecombining split in VNB (herein, VNBI and VNBII). VNBII was enriched for clinical samples relative to VNBI, while phenotypic profiling of 183 isolates demonstrated that VNBI isolates were significantly more resistant to oxidative stress and more heavily melanized than VNBII isolates. Lack of melanization in both lineages was associated with loss-of-function mutations in the BZP4 transcription factor. A genome-wide association study across all VNB isolates revealed sequence differences between clinical and environmental isolates in virulence factors and stress response genes. Inositol transporters and catabolism genes, which process sugars present in plants and the human nervous system, were identified as targets of selection in all three lineages. Further phylogenetic and population genomic analyses revealed extensive loss of genetic diversity in VNBI, suggestive of a history of population bottlenecks, along with unique evolutionary trajectories for mating type loci. These data highlight the complex evolutionary interplay between adaptation to natural environments and opportunistic infections, and that selection on specific pathways may predispose isolates to human virulence.
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Affiliation(s)
| | - Charles Giamberardino
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Sean M Sykes
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Chen-Hsin Yu
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Jennifer L Tenor
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Yuan Chen
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Timothy Yang
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Alexander M Jones
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Sheng Sun
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Miriam R Haverkamp
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Anastasia P Litvintseva
- Mycotic Diseases Branch, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30329, USA
| | - John R Perfect
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Christina A Cuomo
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
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20
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Role of the inositol pyrophosphate multikinase Kcs1 in Cryptococcus inositol metabolism. Fungal Genet Biol 2018; 113:42-51. [PMID: 29357302 DOI: 10.1016/j.fgb.2018.01.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 01/08/2018] [Accepted: 01/14/2018] [Indexed: 12/20/2022]
Abstract
Cryptococcus neoformans is the most common cause of deadly fungal meningitis. This fungus has a complex inositol acquisition and utilization system, and our previous studies have shown the importance of inositol utilization in cryptococcal development and virulence. However, how inositol utilization is regulated in this fungus remains unknown. In this study, we found that inositol, irrespective of the presence of glucose in the media, represses the expression of C. neoformans genes involved in inositol pyrophosphate biosynthesis, including the gene encoding inositol hexakisphosphate kinase Kcs1. Kcs1 was recently reported to regulate inositol metabolism in Saccharomyces cerevisiae and to impact virulence in C. neoformans. To examine the potential role of Kcs1 in inositol regulation in C. neoformans, we generated the kcs1Δ mutant and compared its phenotype with the wild type strain. We found that Kcs1 negatively regulates inositol uptake and catabolism in C. neoformans, but, in contrast to Kcs1 function in S. cerevisiae, does not appear to regulate inositol biosynthesis. Together, these results show that Kcs1 functions to fine-tune inositol acquisition to maintain inositol homeostasis in C. neoformans.
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21
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Pasricha S, MacRae JI, Chua HH, Chambers J, Boyce KJ, McConville MJ, Andrianopoulos A. Extensive Metabolic Remodeling Differentiates Non-pathogenic and Pathogenic Growth Forms of the Dimorphic Pathogen Talaromyces marneffei. Front Cell Infect Microbiol 2017; 7:368. [PMID: 28861398 PMCID: PMC5563070 DOI: 10.3389/fcimb.2017.00368] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Accepted: 07/31/2017] [Indexed: 11/13/2022] Open
Abstract
Fungal infections are an increasing public health problem, particularly in immunocompromised individuals. While these pathogenic fungi show polyphyletic origins with closely related non-pathogenic species, many undergo morphological transitions to produce pathogenic cell types that are associated with increased virulence. However, the characteristics of these pathogenic cells that contribute to virulence are poorly defined. Talaromyces marneffei grows as a non-pathogenic hyphal form at 25°C but undergoes a dimorphic transition to a pathogenic yeast form at 37°C in vitro and following inhalation of asexual conidia by a host. Here we show that this transition is associated with major changes in central carbon metabolism, and that these changes are correlated with increased virulence of the yeast form. Comprehensive metabolite profiling and 13C-labeling studies showed that hyphal cells exhibited very active glycolytic metabolism and contain low levels of internal carbohydrate reserves. In contrast, yeast cells fully catabolized glucose in the mitochondrial TCA cycle, and store excess glucose in large intracellular pools of trehalose and mannitol. Inhibition of the yeast TCA cycle inhibited replication in culture and in host cells. Yeast, but not hyphae, were also able to use myo-inositol and amino acids as secondary carbon sources, which may support their survival in host macrophages. These analyses suggest that T. marneffei yeast cells exhibit a more efficient oxidative metabolism and are capable of utilizing a diverse range of carbon sources, which contributes to their virulence in animal tissues, highlighting the importance of dimorphic switching in pathogenic yeast.
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Affiliation(s)
- Shivani Pasricha
- Genetics, Genomics and Systems Biology, School of BioSciences, University of MelbourneParkville, VIC, Australia
| | - James I MacRae
- Department of Biochemistry and Molecular Biology, Bio21 Institute of Molecular Science and Biotechnology, University of MelbourneParkville, VIC, Australia
| | - Hwa H Chua
- Department of Biochemistry and Molecular Biology, Bio21 Institute of Molecular Science and Biotechnology, University of MelbourneParkville, VIC, Australia
| | - Jenny Chambers
- Department of Biochemistry and Molecular Biology, Bio21 Institute of Molecular Science and Biotechnology, University of MelbourneParkville, VIC, Australia
| | - Kylie J Boyce
- Genetics, Genomics and Systems Biology, School of BioSciences, University of MelbourneParkville, VIC, Australia
| | - Malcolm J McConville
- Department of Biochemistry and Molecular Biology, Bio21 Institute of Molecular Science and Biotechnology, University of MelbourneParkville, VIC, Australia
| | - Alex Andrianopoulos
- Genetics, Genomics and Systems Biology, School of BioSciences, University of MelbourneParkville, VIC, Australia
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22
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Abstract
To respond to the changing environment, cells must be able to sense external conditions. This is important for many processes including growth, mating, the expression of virulence factors, and several other regulatory effects. Nutrient sensing at the plasma membrane is mediated by different classes of membrane proteins that activate downstream signaling pathways: nontransporting receptors, transceptors, classical and nonclassical G-protein-coupled receptors, and the newly defined extracellular mucin receptors. Nontransporting receptors have the same structure as transport proteins, but have lost the capacity to transport while gaining a receptor function. Transceptors are transporters that also function as a receptor, because they can rapidly activate downstream signaling pathways. In this review, we focus on these four types of fungal membrane proteins. We mainly discuss the sensing mechanisms relating to sugars, ammonium, and amino acids. Mechanisms for other nutrients, such as phosphate and sulfate, are discussed briefly. Because the model yeast Saccharomyces cerevisiae has been the most studied, especially regarding these nutrient-sensing systems, each subsection will commence with what is known in this species.
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23
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Niu C, Payne GA, Woloshuk CP. Involvement of FST1 from Fusarium verticillioides in virulence and transport of inositol. MOLECULAR PLANT PATHOLOGY 2017; 18:695-707. [PMID: 27195938 PMCID: PMC6638204 DOI: 10.1111/mpp.12430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 05/11/2016] [Accepted: 05/13/2016] [Indexed: 06/05/2023]
Abstract
Fumonisin B1 (FB1), a polyketide mycotoxin produced by Fusarium verticillioides during the colonization of maize kernels, is detrimental to human and animal health. FST1 encodes a putative protein with 12 transmembrane domains; however, its function remains unknown. The FST1 gene is highly expressed by the fungus in the endosperm of maize kernels compared with the levels of expression in germ tissues. Previous research has shown that FST1 affects FB1 production, virulence, hydrogen peroxide resistance, hydrophobicity and macroconidia production. Here, we examine the phylogeny of FST1, its expression in a Saccharomyces cerevisiae strain lacking a functional myo-inositol transporter (ITR1) and the effect of amino acid changes in the central loop and C-terminus regions of FST1 on functionality. The results indicate that expression of FST1 in an ITR1 mutant strain restores growth on myo-inositol medium to wild-type levels and restores the inhibitory effects of FB1, suggesting that FST1 can transport both myo-inositol and FB1 into yeast cells. Our results with engineered FST1 also indicate that amino acids in the central loop and C-terminus regions are important for FST1 functionality in both S. cerevisiae and F. verticillioides. Overall, this research has established the first characterized inositol transporter in filamentous fungi and has advanced our knowledge about the global regulatory functions of FST1.
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Affiliation(s)
- Chenxing Niu
- Department of Botany and Plant PathologyPurdue UniversityWest LafayetteIN47907‐2054USA
| | - Gary A. Payne
- Department of Plant PathologyNorth Carolina State UniversityRaleighNC27695‐7567USA
| | - Charles P. Woloshuk
- Department of Botany and Plant PathologyPurdue UniversityWest LafayetteIN47907‐2054USA
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Continental Drift and Speciation of the Cryptococcus neoformans and Cryptococcus gattii Species Complexes. mSphere 2017; 2:mSphere00103-17. [PMID: 28435888 PMCID: PMC5397565 DOI: 10.1128/msphere.00103-17] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 04/04/2017] [Indexed: 01/24/2023] Open
Abstract
Genomic analysis has placed the origins of two human-pathogenic fungi, the Cryptococcus gattii species complex and the Cryptococcus neoformans species complex, in South America and Africa, respectively. Molecular clock calculations suggest that the two species separated ~80 to 100 million years ago. This time closely approximates the breakup of the supercontinent Pangea, which gave rise to South America and Africa. On the basis of the geographic distribution of these two species complexes and the coincidence of the evolutionary divergence and Pangea breakup times, we propose that a spatial separation caused by continental drift resulted in the emergence of the C. gattii and C. neoformans species complexes from a Pangean ancestor. We note that, despite the spatial and temporal separation that occurred approximately 100 million years ago, these two species complexes are morphologically similar, share virulence factors, and cause very similar diseases. Continuation of these phenotypic characteristics despite ancient separation suggests the maintenance of similar selection pressures throughout geologic ages.
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25
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de Vries RP, Riley R, Wiebenga A, Aguilar-Osorio G, Amillis S, Uchima CA, Anderluh G, Asadollahi M, Askin M, Barry K, Battaglia E, Bayram Ö, Benocci T, Braus-Stromeyer SA, Caldana C, Cánovas D, Cerqueira GC, Chen F, Chen W, Choi C, Clum A, dos Santos RAC, Damásio ARDL, Diallinas G, Emri T, Fekete E, Flipphi M, Freyberg S, Gallo A, Gournas C, Habgood R, Hainaut M, Harispe ML, Henrissat B, Hildén KS, Hope R, Hossain A, Karabika E, Karaffa L, Karányi Z, Kraševec N, Kuo A, Kusch H, LaButti K, Lagendijk EL, Lapidus A, Levasseur A, Lindquist E, Lipzen A, Logrieco AF, MacCabe A, Mäkelä MR, Malavazi I, Melin P, Meyer V, Mielnichuk N, Miskei M, Molnár ÁP, Mulé G, Ngan CY, Orejas M, Orosz E, Ouedraogo JP, Overkamp KM, Park HS, Perrone G, Piumi F, Punt PJ, Ram AFJ, Ramón A, Rauscher S, Record E, Riaño-Pachón DM, Robert V, Röhrig J, Ruller R, Salamov A, Salih NS, Samson RA, Sándor E, Sanguinetti M, Schütze T, Sepčić K, Shelest E, Sherlock G, Sophianopoulou V, Squina FM, Sun H, Susca A, Todd RB, Tsang A, Unkles SE, van de Wiele N, van Rossen-Uffink D, Oliveira JVDC, Vesth TC, Visser J, Yu JH, Zhou M, Andersen MR, Archer DB, Baker SE, Benoit I, Brakhage AA, Braus GH, Fischer R, Frisvad JC, Goldman GH, Houbraken J, Oakley B, Pócsi I, Scazzocchio C, Seiboth B, vanKuyk PA, Wortman J, Dyer PS, Grigoriev IV. Comparative genomics reveals high biological diversity and specific adaptations in the industrially and medically important fungal genus Aspergillus. Genome Biol 2017; 18:28. [PMID: 28196534 PMCID: PMC5307856 DOI: 10.1186/s13059-017-1151-0] [Citation(s) in RCA: 316] [Impact Index Per Article: 45.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 01/10/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The fungal genus Aspergillus is of critical importance to humankind. Species include those with industrial applications, important pathogens of humans, animals and crops, a source of potent carcinogenic contaminants of food, and an important genetic model. The genome sequences of eight aspergilli have already been explored to investigate aspects of fungal biology, raising questions about evolution and specialization within this genus. RESULTS We have generated genome sequences for ten novel, highly diverse Aspergillus species and compared these in detail to sister and more distant genera. Comparative studies of key aspects of fungal biology, including primary and secondary metabolism, stress response, biomass degradation, and signal transduction, revealed both conservation and diversity among the species. Observed genomic differences were validated with experimental studies. This revealed several highlights, such as the potential for sex in asexual species, organic acid production genes being a key feature of black aspergilli, alternative approaches for degrading plant biomass, and indications for the genetic basis of stress response. A genome-wide phylogenetic analysis demonstrated in detail the relationship of the newly genome sequenced species with other aspergilli. CONCLUSIONS Many aspects of biological differences between fungal species cannot be explained by current knowledge obtained from genome sequences. The comparative genomics and experimental study, presented here, allows for the first time a genus-wide view of the biological diversity of the aspergilli and in many, but not all, cases linked genome differences to phenotype. Insights gained could be exploited for biotechnological and medical applications of fungi.
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Affiliation(s)
- Ronald P. de Vries
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
- Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Robert Riley
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Ad Wiebenga
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
- Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Guillermo Aguilar-Osorio
- Department of Food Science and Biotechnology, Faculty of Chemistry, National University of Mexico, Ciudad Universitaria, D.F. C.P. 04510 Mexico
| | - Sotiris Amillis
- Department of Biology, National and Kapodistrian University of Athens, Panepistimioupolis, 15781 Athens, Greece
| | - Cristiane Akemi Uchima
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192 CEP 13083-970, Campinas, São Paulo Brasil
- Present address: VTT Brasil, Alameda Inajá, 123, CEP 06460-055 Barueri, São Paulo Brazil
| | - Gregor Anderluh
- Laboratory for Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Mojtaba Asadollahi
- Department of Biochemical Engineering, Faculty of Science and Technology, University of Debrecen, 4032 Debrecen, Hungary
| | - Marion Askin
- Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
- Present address: CSIRO Publishing, Unipark, Building 1 Level 1, 195 Wellington Road, Clayton, VIC 3168 Australia
| | - Kerrie Barry
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Evy Battaglia
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
- Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Özgür Bayram
- Department of Molecular Microbiology and Genetics, Institute for Microbiology and Genetics, Georg August University Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany
- Department of Biology, Maynooth University, Maynooth, Co. Kildare Ireland
| | - Tiziano Benocci
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
- Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Susanna A. Braus-Stromeyer
- Department of Molecular Microbiology and Genetics, Institute for Microbiology and Genetics, Georg August University Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany
| | - Camila Caldana
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192 CEP 13083-970, Campinas, São Paulo Brasil
- Max Planck Partner Group, Brazilian Bioethanol Science and Technology Laboratory, CEP 13083-100 Campinas, Sao Paulo Brazil
| | - David Cánovas
- Department of Genetics, Faculty of Biology, University of Seville, Avda de Reina Mercedes 6, 41012 Sevilla, Spain
- Fungal Genetics and Genomics Unit, Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences (BOKU) Vienna, Vienna, Austria
| | | | - Fusheng Chen
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan, 430070 China
| | - Wanping Chen
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan, 430070 China
| | - Cindy Choi
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Alicia Clum
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Renato Augusto Corrêa dos Santos
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192 CEP 13083-970, Campinas, São Paulo Brasil
| | - André Ricardo de Lima Damásio
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192 CEP 13083-970, Campinas, São Paulo Brasil
- Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, CEP 13083-862 Campinas, SP Brazil
| | - George Diallinas
- Department of Biology, National and Kapodistrian University of Athens, Panepistimioupolis, 15781 Athens, Greece
| | - Tamás Emri
- Department of Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
| | - Erzsébet Fekete
- Department of Biochemical Engineering, Faculty of Science and Technology, University of Debrecen, 4032 Debrecen, Hungary
| | - Michel Flipphi
- Department of Biochemical Engineering, Faculty of Science and Technology, University of Debrecen, 4032 Debrecen, Hungary
| | - Susanne Freyberg
- Department of Molecular Microbiology and Genetics, Institute for Microbiology and Genetics, Georg August University Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany
| | - Antonia Gallo
- Institute of Sciences of Food Production (ISPA), National Research Council (CNR), via Provinciale Lecce-Monteroni, 73100 Lecce, Italy
| | - Christos Gournas
- Institute of Biosciences and Applications, Microbial Molecular Genetics Laboratory, National Center for Scientific Research, Demokritos (NCSRD), Athens, Greece
- Present address: Université Libre de Bruxelles Institute of Molecular Biology and Medicine (IBMM), Brussels, Belgium
| | - Rob Habgood
- School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD UK
| | | | - María Laura Harispe
- Institut Pasteur de Montevideo, Unidad Mixta INIA-IPMont, Mataojo 2020, CP11400 Montevideo, Uruguay
- Present address: Instituto de Profesores Artigas, Consejo de Formación en Educación, ANEP, CP 11800, Av. del Libertador 2025, Montevideo, Uruguay
| | - Bernard Henrissat
- CNRS, Aix-Marseille Université, Marseille, France
- INRA, USC 1408 AFMB, 13288 Marseille, France
- Department of Biological Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Kristiina S. Hildén
- Department of Food and Environmental Sciences, University of Helsinki, Viikinkaari 9, Helsinki, Finland
| | - Ryan Hope
- School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD UK
| | - Abeer Hossain
- Dutch DNA Biotech BV, Utrechtseweg 48, 3703AJ Zeist, The Netherlands
- Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Eugenia Karabika
- School of Biology, University of St Andrews, St Andrews, Fife KY16 9TH UK
- Present Address: Department of Chemistry, University of Ioannina, Ioannina, 45110 Greece
| | - Levente Karaffa
- Department of Biochemical Engineering, Faculty of Science and Technology, University of Debrecen, 4032 Debrecen, Hungary
| | - Zsolt Karányi
- Department of Medicine, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, 4032 Debrecen, Hungary
| | - Nada Kraševec
- Laboratory for Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Alan Kuo
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Harald Kusch
- Department of Molecular Microbiology and Genetics, Institute for Microbiology and Genetics, Georg August University Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany
- Department of Medical Informatics, University Medical Centre, Robert-Koch-Str.40, 37075 Göttingen, Germany
- Department of Molecular Biology, Universitätsmedizin Göttingen, Humboldtallee 23, Göttingen, 37073 Germany
| | - Kurt LaButti
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Ellen L. Lagendijk
- Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Alla Lapidus
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
- Present address: Center for Algorithmic Biotechnology, St.Petersburg State University, St. Petersburg, Russia
| | - Anthony Levasseur
- INRA, Aix-Marseille Univ, BBF, Biodiversité et Biotechnologie Fongiques, Marseille, France
- Present address: Aix-Marseille Université, Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes (URMITE), UM63, CNRS 7278, IRD 198, INSERM U1095, IHU Méditerranée Infection, Pôle des Maladies Infectieuses, Assistance Publique-Hôpitaux de Marseille, Faculté de Médecine, 27 Bd Jean Moulin, 13005 Marseille, France
| | - Erika Lindquist
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Anna Lipzen
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Antonio F. Logrieco
- Institute of Sciences of Food Production (ISPA), National Research Council (CNR), Via Amendola 122/O, 70126 Bari, Italy
| | - Andrew MacCabe
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas (CSIC), Paterna, Valencia, Spain
| | - Miia R. Mäkelä
- Department of Food and Environmental Sciences, University of Helsinki, Viikinkaari 9, Helsinki, Finland
| | - Iran Malavazi
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, São Paulo Brazil
| | - Petter Melin
- Uppsala BioCenter, Department of Microbiology, Swedish University of Agricultural Sciences, P.O. Box 7025, 750 07 Uppsala, Sweden
- Present address: Swedish Chemicals Agency, Box 2, 172 13 Sundbyberg, Sweden
| | - Vera Meyer
- Institute of Biotechnology, Department Applied and Molecular Microbiology, Berlin University of Technology, Gustav-Meyer-Allee 25, 13355 Berlin, Germany
| | - Natalia Mielnichuk
- Department of Genetics, Faculty of Biology, University of Seville, Avda de Reina Mercedes 6, 41012 Sevilla, Spain
- Present address: Instituto de Ciencia y Tecnología Dr. César Milstein, Fundación Pablo Cassará, CONICET, Saladillo 2468 C1440FFX, Ciudad de Buenos Aires, Argentina
| | - Márton Miskei
- Department of Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
- MTA-DE Momentum, Laboratory of Protein Dynamics, Department of Biochemistry and Molecular Biology, University of Debrecen, Nagyerdei krt.98., 4032 Debrecen, Hungary
| | - Ákos P. Molnár
- Department of Biochemical Engineering, Faculty of Science and Technology, University of Debrecen, 4032 Debrecen, Hungary
| | - Giuseppina Mulé
- Institute of Sciences of Food Production (ISPA), National Research Council (CNR), Via Amendola 122/O, 70126 Bari, Italy
| | - Chew Yee Ngan
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Margarita Orejas
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas (CSIC), Paterna, Valencia, Spain
| | - Erzsébet Orosz
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
- Department of Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
| | - Jean Paul Ouedraogo
- Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
- Present address: Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke Street West, Montreal, QC H4B 1R6 Canada
| | - Karin M. Overkamp
- Dutch DNA Biotech BV, Utrechtseweg 48, 3703AJ Zeist, The Netherlands
| | - Hee-Soo Park
- School of Food Science and Biotechnology, Kyungpook National University, Daegu, 702-701 Republic of Korea
| | - Giancarlo Perrone
- Institute of Sciences of Food Production (ISPA), National Research Council (CNR), Via Amendola 122/O, 70126 Bari, Italy
| | - Francois Piumi
- INRA, Aix-Marseille Univ, BBF, Biodiversité et Biotechnologie Fongiques, Marseille, France
- Present address: INRA UMR1198 Biologie du Développement et de la Reproduction - Domaine de Vilvert, Jouy en Josas, 78352 Cedex France
| | - Peter J. Punt
- Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
- Dutch DNA Biotech BV, Utrechtseweg 48, 3703AJ Zeist, The Netherlands
| | - Arthur F. J. Ram
- Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Ana Ramón
- Sección Bioquímica, Departamento de Biología Celular y Molecular, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Stefan Rauscher
- Department of Microbiology, Karlsruhe Institute of Technology, Institute for Applied Biosciences, Hertzstrasse 16,, 76187 Karlsruhe, Germany
| | - Eric Record
- INRA, Aix-Marseille Univ, BBF, Biodiversité et Biotechnologie Fongiques, Marseille, France
| | - Diego Mauricio Riaño-Pachón
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192 CEP 13083-970, Campinas, São Paulo Brasil
| | - Vincent Robert
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Julian Röhrig
- Department of Microbiology, Karlsruhe Institute of Technology, Institute for Applied Biosciences, Hertzstrasse 16,, 76187 Karlsruhe, Germany
| | - Roberto Ruller
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192 CEP 13083-970, Campinas, São Paulo Brasil
| | - Asaf Salamov
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Nadhira S. Salih
- School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD UK
- Department of Biology, School of Science, University of Sulaimani, Al Sulaymaneyah, Iraq
| | - Rob A. Samson
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Erzsébet Sándor
- Institute of Food Science, Faculty of Agricultural and Food Sciences and Environmental Management, University of Debrecen, 4032 Debrecen, Hungary
| | - Manuel Sanguinetti
- Sección Bioquímica, Departamento de Biología Celular y Molecular, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Tabea Schütze
- Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
- Present address: Department Applied and Molecular Microbiology, Institute of Biotechnology, Berlin University of Technology, Gustav-Meyer-Allee 25, 13355 Berlin, Germany
| | - Kristina Sepčić
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana, Slovenia
| | - Ekaterina Shelest
- Systems Biology/Bioinformatics group, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, (HKI), Beutenbergstr. 11a, 07745 Jena, Germany
| | - Gavin Sherlock
- Department of Genetics, Stanford University, Stanford, CA 94305-5120 USA
| | - Vicky Sophianopoulou
- Institute of Biosciences and Applications, Microbial Molecular Genetics Laboratory, National Center for Scientific Research, Demokritos (NCSRD), Athens, Greece
| | - Fabio M. Squina
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192 CEP 13083-970, Campinas, São Paulo Brasil
| | - Hui Sun
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Antonia Susca
- Institute of Sciences of Food Production (ISPA), National Research Council (CNR), Via Amendola 122/O, 70126 Bari, Italy
| | - Richard B. Todd
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506 USA
| | - Adrian Tsang
- Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke Street West, Montreal, QC H4B 1R6 Canada
| | - Shiela E. Unkles
- School of Biology, University of St Andrews, St Andrews, Fife KY16 9TH UK
| | - Nathalie van de Wiele
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Diana van Rossen-Uffink
- Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
- Present address: BaseClear B.V., Einsteinweg 5, 2333 CC Leiden, The Netherlands
| | - Juliana Velasco de Castro Oliveira
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192 CEP 13083-970, Campinas, São Paulo Brasil
| | - Tammi C. Vesth
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 223, 2800 Kongens Lyngby, Denmark
| | - Jaap Visser
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Jae-Hyuk Yu
- Departments of Bacteriology and Genetics, University of Wisconsin-Madison, 1550 Linden Drive, Madison, WI 53706 USA
| | - Miaomiao Zhou
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
- Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Mikael R. Andersen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 223, 2800 Kongens Lyngby, Denmark
| | - David B. Archer
- School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD UK
| | - Scott E. Baker
- Fungal Biotechnology Team, Pacific Northwest National Laboratory, Richland, Washington, 99352 USA
| | - Isabelle Benoit
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
- Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
- Present address: Centre of Functional and Structure Genomics Biology Department Concordia University, 7141 Sherbrooke St. W., Montreal, QC H4B 1R6 Canada
| | - Axel A. Brakhage
- Department of Molecular and Applied Microbiology, Leibniz-Institute for Natural Product Research and Infection Biology - Hans Knoell Institute (HKI) and Institute for Microbiology, Friedrich Schiller University Jena, Beutenbergstr. 11a, 07745 Jena, Germany
| | - Gerhard H. Braus
- Department of Molecular Microbiology and Genetics, Institute for Microbiology and Genetics, Georg August University Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany
| | - Reinhard Fischer
- Department of Microbiology, Karlsruhe Institute of Technology, Institute for Applied Biosciences, Hertzstrasse 16,, 76187 Karlsruhe, Germany
| | - Jens C. Frisvad
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 223, 2800 Kongens Lyngby, Denmark
| | - Gustavo H. Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café S/N, CEP 14040-903 Ribeirão Preto, São Paulo Brazil
| | - Jos Houbraken
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Berl Oakley
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas 66045 USA
| | - István Pócsi
- Department of Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
| | - Claudio Scazzocchio
- Department of Microbiology, Imperial College, London, SW7 2AZ UK
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, University Paris‐Sud, Université Paris‐Saclay, 91198 Gif‐sur‐Yvette cedex, France
| | - Bernhard Seiboth
- Research Division Biochemical Technology, Institute of Chemical Engineering, TU Wien, Gumpendorferstraße 1a, 1060 Vienna, Austria
| | - Patricia A. vanKuyk
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
- Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Jennifer Wortman
- Broad Institute, 415 Main St, Cambridge, MA 02142 USA
- Present address: Seres Therapeutics, 200 Sidney St, Cambridge, MA 02139 USA
| | - Paul S. Dyer
- School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD UK
| | - Igor V. Grigoriev
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
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Steenwyk JL, Soghigian JS, Perfect JR, Gibbons JG. Copy number variation contributes to cryptic genetic variation in outbreak lineages of Cryptococcus gattii from the North American Pacific Northwest. BMC Genomics 2016; 17:700. [PMID: 27590805 PMCID: PMC5009542 DOI: 10.1186/s12864-016-3044-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 08/24/2016] [Indexed: 12/13/2022] Open
Abstract
Background Copy number variants (CNVs) are a class of structural variants (SVs) and are defined as fragments of DNA that are present at variable copy number in comparison with a reference genome. Recent advances in bioinformatics methodologies and sequencing technologies have enabled the high-resolution quantification of genome-wide CNVs. In pathogenic fungi SVs have been shown to alter gene expression, influence host specificity, and drive fungicide resistance, but little attention has focused specifically on CNVs. Using publicly available sequencing data, we identified 90 isolates across 212 Cryptococcus gattii genomes that belong to the VGII subgroups responsible for the recent deadly outbreaks in the North American Pacific Northwest. We generated CNV profiles for each sample to investigate the prevalence and function of CNV in C. gattii. Results We identified eight genetic clusters among publicly available Illumina whole genome sequence data from 212 C. gattii isolates through population structure analysis. Three clusters represent the VGIIa, VGIIb, and VGIIc subgroups from the North American Pacific Northwest. CNV was bioinformatically predicted and affected ~300–400 Kilobases (Kb) of the C. gattii VGII subgroup genomes. Sixty-seven loci, encompassing 58 genes, showed highly divergent patterns of copy number variation between VGII subgroups. Analysis of PFam domains within divergent CN variable genes revealed enrichment of protein domains associated with transport, cell wall organization and external encapsulating structure. Conclusions CNVs may contribute to pathological and phenotypic differences observed between the C. gattii VGIIa, VGIIb, and VGIIc subpopulations. Genes overlapping with population differentiated CNVs were enriched for several virulence related functional terms. These results uncover novel candidate genes to examine the genetic and functional underpinnings of C. gattii pathogenicity. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3044-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jacob L Steenwyk
- Biology Department, Clark University, 950 Main Street, Worcester, MA, USA.,Current address: Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - John S Soghigian
- Biology Department, Clark University, 950 Main Street, Worcester, MA, USA.,Current address: Department of Environmental Sciences, The Connecticut Agricultural Experiment Station, New Haven, CT, USA
| | - John R Perfect
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, NC, USA
| | - John G Gibbons
- Biology Department, Clark University, 950 Main Street, Worcester, MA, USA.
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Abstract
Cryptococcus neoformans is a human fungal pathogen and a major cause of fungal meningitis in immunocompromised individuals. Treatment options for cryptococcosis are limited. Of the two major antifungal drug classes, azoles are active against C. neoformans but exert a fungistatic effect, necessitating long treatment regimens and leaving open an avenue for emergence of azole resistance. Drugs of the echinocandin class, which target the glucan synthase and are fungicidal against a number of other fungal pathogens, such as Candida species, are ineffective against C. neoformans. Despite the sensitivity of the target enzyme to the drug, the reasons for the innate resistance of C. neoformans to echinocandins remain unknown. To understand the mechanism of echinocandin resistance in C. neoformans, we screened gene disruption and gene deletion libraries for mutants sensitive to the echinocandin-class drug caspofungin and identified a mutation of CDC50, which encodes the β-subunit of membrane lipid flippase. We found that the Cdc50 protein localized to membranes and that its absence led to plasma membrane defects and enhanced caspofungin penetration into the cell, potentially explaining the increased caspofungin sensitivity. Loss of CDC50 also led to hypersensitivity to the azole-class drug fluconazole. Interestingly, in addition to functioning in drug resistance, CDC50 was also essential for fungal resistance to macrophage killing and for virulence in a murine model of cryptococcosis. Furthermore, the surface of cdc50Δ cells contained increased levels of phosphatidylserine, which has been proposed to act as a macrophage recognition signal. Together, these results reveal a previously unappreciated role of membrane lipid flippase in C. neoformans drug resistance and virulence. Cryptococcus neoformans is a fungal pathogen that is the most common cause of fungal meningitis, causing over 620,000 deaths annually. The treatment options for cryptococcosis are very limited. The most commonly used drugs are either fungistatic (azoles) or highly toxic (amphotericin B). Echinocandins are the newest fungicidal drug class that works well in treating candidiasis and aspergillosis, yet they are ineffective in treating cryptococcosis. In this study, we showed that the regulatory subunit of the lipid translocase (flippase), a protein that regulates the asymmetrical orientation of membrane lipids, is required for C. neoformans resistance to caspofungin, as well as for virulence during infection. This discovery identifies lipid flippase as a potential C. neoformans drug target, which plays an important role in the innate resistance of C. neoformans to echinocandins and in fungal virulence.
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Jung KW, Yang DH, Maeng S, Lee KT, So YS, Hong J, Choi J, Byun HJ, Kim H, Bang S, Song MH, Lee JW, Kim MS, Kim SY, Ji JH, Park G, Kwon H, Cha S, Meyers GL, Wang LL, Jang J, Janbon G, Adedoyin G, Kim T, Averette AK, Heitman J, Cheong E, Lee YH, Lee YW, Bahn YS. Systematic functional profiling of transcription factor networks in Cryptococcus neoformans. Nat Commun 2015; 6:6757. [PMID: 25849373 PMCID: PMC4391232 DOI: 10.1038/ncomms7757] [Citation(s) in RCA: 122] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 02/24/2015] [Indexed: 02/06/2023] Open
Abstract
Cryptococcus neoformans causes life-threatening meningoencephalitis in humans, but its overall biological and pathogenic regulatory circuits remain elusive, particularly due to the presence of an evolutionarily divergent set of transcription factors (TFs). Here, we report the construction of a high-quality library of 322 signature-tagged gene-deletion strains for 155 putative TF genes previously predicted using the DNA-binding domain TF database, and examine their in vitro and in vivo phenotypic traits under 32 distinct growth conditions. At least one phenotypic trait is exhibited by 145 out of 155 TF mutants (93%) and ∼85% of them (132/155) are functionally characterized for the first time in this study. The genotypic and phenotypic data for each TF are available in the C. neoformans TF phenome database (http://tf.cryptococcus.org). In conclusion, our phenome-based functional analysis of the C. neoformans TF mutant library provides key insights into transcriptional networks of basidiomycetous fungi and human fungal pathogens.
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Affiliation(s)
- Kwang-Woo Jung
- Department of Biotechnology, Center for Fungal Pathogenesis, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Dong-Hoon Yang
- Department of Biotechnology, Center for Fungal Pathogenesis, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Shinae Maeng
- Department of Biotechnology, Center for Fungal Pathogenesis, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Kyung-Tae Lee
- Department of Biotechnology, Center for Fungal Pathogenesis, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Yee-Seul So
- Department of Biotechnology, Center for Fungal Pathogenesis, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Joohyeon Hong
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Jaeyoung Choi
- Department of Agricultural Biotechnology, Center for Fungal Pathogenesis, Seoul National University, Seoul 151-921, Korea
| | - Hyo-Jeong Byun
- Department of Biotechnology, Center for Fungal Pathogenesis, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Hyelim Kim
- Department of Biotechnology, Center for Fungal Pathogenesis, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Soohyun Bang
- Department of Biotechnology, Center for Fungal Pathogenesis, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Min-Hee Song
- Department of Biotechnology, Center for Fungal Pathogenesis, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Jang-Won Lee
- Department of Biotechnology, Center for Fungal Pathogenesis, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Min Su Kim
- Department of Biotechnology, Center for Fungal Pathogenesis, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Seo-Young Kim
- Department of Biotechnology, Center for Fungal Pathogenesis, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Je-Hyun Ji
- Department of Biotechnology, Center for Fungal Pathogenesis, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Goun Park
- Department of Biotechnology, Center for Fungal Pathogenesis, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Hyojeong Kwon
- Department of Biotechnology, Center for Fungal Pathogenesis, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Suyeon Cha
- Department of Biotechnology, Center for Fungal Pathogenesis, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Gena Lee Meyers
- Department of Biotechnology, Center for Fungal Pathogenesis, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Li Li Wang
- Department of Biotechnology, Center for Fungal Pathogenesis, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Jooyoung Jang
- Department of Biotechnology, Center for Fungal Pathogenesis, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Guilhem Janbon
- Unité Biologie et Pathogénicité Fongiques, Département de Mycologie, Institut Pasteur, Paris F-75015, France
| | - Gloria Adedoyin
- Department of Molecular Genetics and Microbiology, Medicine, and Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Taeyup Kim
- Department of Molecular Genetics and Microbiology, Medicine, and Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Anna K. Averette
- Department of Molecular Genetics and Microbiology, Medicine, and Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Medicine, and Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Eunji Cheong
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Yong-Hwan Lee
- Department of Agricultural Biotechnology, Center for Fungal Pathogenesis, Seoul National University, Seoul 151-921, Korea
| | - Yin-Won Lee
- Department of Agricultural Biotechnology, Center for Fungal Pathogenesis, Seoul National University, Seoul 151-921, Korea
| | - Yong-Sun Bahn
- Department of Biotechnology, Center for Fungal Pathogenesis, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
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Abstract
UNLABELLED Cryptococcosis is an opportunistic infection due to the ubiquitous yeast Cryptococcus neoformans. This yeast interacts closely with innate immune cells, leading to various fates, including fungal persistence within cells, making possible the dissemination of the yeast cells with monocytes via a Trojan horse strategy. In humans, the natural history of the infection begins with primoinfection during childhood, which is followed by dormancy and, in some individuals, reactivation upon immunosuppression. To address the question of dormancy, we studied C. neoformans infection at the macrophage level (in vitro H99-macrophage interaction) and at the organ level in a murine model of cryptococcosis. We analyzed the diversity of yeast adaptation to the host by characterizing several C. neoformans populations with new assays based on flow cytometry (quantitative flow cytometry, multispectral imaging flow cytometry, sorting), microscopy (dynamic imaging), and gene expression analysis. On the basis of parameters of multiplication and stress response, various populations of yeast cells were observed over time in vivo and in vitro. Cell sorting allowed the identification of a subpopulation that was less prone to grow under standard conditions than the other populations, with growth enhanced by the addition of serum. Gene expression analysis revealed that this population had specific metabolic characteristics that could reflect dormancy. Our data suggest that dormant yeast cells could exist in vitro and in vivo. C. neoformans exhibits a huge plasticity and adaptation to hosts that deserves further study. In vitro generation of dormant cells is now the main challenge to overcome the limited number of yeast cells recovered in our models. IMPORTANCE Cryptococcus neoformans is a sugar-coated unicellular fungus that interacts closely with various cells and organisms, including amoebas, nematodes, and immune cells of mammals. This yeast is able to proliferate and survive in the intracellular environment. C. neoformans causes cryptococcosis, and yeast dormancy in humans has been suggested on the basis of epidemiological evidence obtained years ago. By studying an in vitro model of yeast-macrophage interaction and murine models of cryptococcosis, we observed that yeast cells evolve in heterogeneous populations during infection on the basis of global metabolic activity. We compared the growth ability and gene expression of yeast cells belonging to various populations in those two models. We eventually found a population of yeast cells with low metabolism that fit some of the criteria for dormant cells. This paves the way for further characterization of dormancy in C. neoformans.
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Schneider S. Inositol transport proteins. FEBS Lett 2015; 589:1049-58. [DOI: 10.1016/j.febslet.2015.03.012] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Revised: 03/05/2015] [Accepted: 03/18/2015] [Indexed: 12/27/2022]
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Finding the sweet spot: how human fungal pathogens acquire and turn the sugar inositol against their hosts. mBio 2015; 6:e00109. [PMID: 25736882 PMCID: PMC4358016 DOI: 10.1128/mbio.00109-15] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Inositol is an essential nutrient with important structural and signaling functions in eukaryotes. Its role in microbial pathogenesis has been reported in fungi, protozoans, and eubacteria. In a recent article, Porollo et al. [mBio 5(6):e01834-14, 2014, doi:10.1128/mBio.01834-14] demonstrated the importance of inositol metabolism in the development and viability of Pneumocystis species—obligate fungal pathogens that remain unculturable in vitro. To understand their obligate nature, the authors used innovative comparative genomic approaches and discovered that Pneumocystis spp. are inositol auxotrophs due to the lack of inositol biosynthetic enzymes and that inositol insufficiency is a contributing factor preventing fungal growth in vitro. This work is in accord with other studies suggesting that inositol plays a conserved role in microbial pathogenesis. Inositol uptake and metabolism therefore may represent novel antimicrobial drug targets. Using comparative genomics to analyze metabolic pathways offers a powerful tool to gain new insights into nutrient utilization in microbes, especially obligate pathogens.
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Sambe MAN, He X, Tu Q, Guo Z. A cold-induced myo-inositol transporter-like gene confers tolerance to multiple abiotic stresses in transgenic tobacco plants. PHYSIOLOGIA PLANTARUM 2015; 153:355-64. [PMID: 25131886 DOI: 10.1111/ppl.12249] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Revised: 03/30/2014] [Accepted: 04/26/2014] [Indexed: 05/15/2023]
Abstract
A full length cDNA encoding a myo-inositol transporter-like protein, named as MfINT-like, was cloned from Medicago sativa subsp. falcata (herein falcata), a species with greater cold tolerance than alfalfa (M. sativa subsp. sativa). MfINT-like is located on plasma membranes. MfINT-like transcript was induced 2-4 h after exogenous myo-inositol treatment, 24-96 h with cold, and 96 h by salinity. Given that myo-inositol accumulates higher in falcata after 24 h of cold treatment, myo-inositol is proposed to be involved in cold-induced expression of MfINT-like. Higher levels of myo-inositol was observed in leaves of transgenic tobacco plants overexpressing MfINT-like than the wild-type but not in the roots of plants grown on myo-inositol containing medium, suggesting that transgenic plants had higher myo-inositol transport activity than the wild-type. Transgenic plants survived better to freezing temperature, and had lower ion leakage and higher maximal photochemical efficiency of photosystem II (Fv /Fm ) after chilling treatment. In addition, greater plant fresh weight was observed in transgenic plants as compared with the wild-type when plants were grown under drought or salinity stress. The results suggest that MfINT-like mediated transport of myo-inositol is associated with plant tolerance to abiotic stresses.
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Affiliation(s)
- Mame Abdou Nahr Sambe
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, South China Agricultural University, Guangzhou, 510642, China
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Liu TB, Subbian S, Pan W, Eugenin E, Xie J, Xue C. Cryptococcus inositol utilization modulates the host protective immune response during brain infection. Cell Commun Signal 2014; 12:51. [PMID: 25201772 PMCID: PMC4172957 DOI: 10.1186/s12964-014-0051-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 08/21/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cryptococcus neoformans is the most common cause of fungal meningitis among individuals with HIV/AIDS, which is uniformly fatal without proper treatment. The underlying mechanism of disease development in the brain that leads to cryptococcal meningoencephalitis remains incompletely understood. We have previously demonstrated that inositol transporters (ITR) are required for Cryptococcus virulence. The itr1aΔ itr3cΔ double mutant of C. neoformans was attenuated for virulence in a murine model of intra-cerebral infection; demonstrating that Itr1a and Itr3c are required for full virulence during brain infection, despite a similar growth rate between the mutant and wild type strains in the infected brain. RESULTS To understand the immune pathology associated with infection by the itr1aΔ itr3cΔ double mutant, we investigated the molecular correlates of host immune response during mouse brain infection. We used genome-wide transcriptome shotgun sequencing (RNA-Seq) and quantitative real-time PCR (qRT-PCR) methods to examine the host gene expression profile in the infected brain. Our results show that compared to the wild type, infection of mouse brains by the mutant leads to significant activation of cellular networks/pathways associated with host protective immunity. Most of the significantly differentially expressed genes (SDEG) are part of immune cell networks such as tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ) regulon, indicating that infection by the mutant mounts a stronger host immune response compared to the wild type. Interestingly, a significant reduction in glucuronoxylomannan (GXM) secretion was observed in the itr1aΔ itr3cΔ mutant cells, indicating that inositol utilization pathways play a role in capsule production. CONCLUSIONS Since capsule has been shown to impact the host response during Cryptococcus-host interactions, our results suggest that the reduced GXM production may contribute to the increased immune activation in the mutant-infected animals.
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Macrae JI, Lopaticki S, Maier AG, Rupasinghe T, Nahid A, Cowman AF, McConville MJ. Plasmodium falciparum is dependent on de novo myo-inositol biosynthesis for assembly of GPI glycolipids and infectivity. Mol Microbiol 2014; 91:762-76. [PMID: 24350823 DOI: 10.1111/mmi.12496] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/15/2013] [Indexed: 12/27/2022]
Abstract
Intra-erythrocytic stages of the malaria parasite, Plasmodium falciparum, are thought to be dependent on de novo synthesis of phosphatidylinositol, as red blood cells (RBC) lack the capacity to synthesize this phospholipid. The myo-inositol headgroup of PI can either be synthesized de novo or scavenged from the RBC. An untargeted metabolite profiling of P. falciparum infected RBC showed that trophozoite and schizont stages accumulate high levels of myo-inositol-3-phosphate, indicating increased de novo biosynthesis of myo-inositol from glucose 6-phosphate. Metabolic labelling studies with (13) C-U-glucose in the presence and absence of exogenous inositol confirmed that de novo myo-inositol synthesis occurs in parallel with myo-inositol salvage pathways. Unexpectedly, while both endogenous and scavenged myo-inositol was used to synthesize bulk PI, only de novo-synthesized myo-inositol was incorporated into GPI glycolipids. Moreover, gene disruption studies suggested that the INO1 gene, encoding myo-inositol 3-phosphate synthase, is essential in asexual parasite stages. Together these findings suggest that P. falciparum asexual stages are critically dependent on de novo myo-inositol biosynthesis for assembly of a sub-pool of PI species and GPI biosynthesis. These findings highlight unexpected complexity in phospholipid biosynthesis in P. falciparum and a lack of redundancy in some nutrient salvage versus endogenous biosynthesis pathways.
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Affiliation(s)
- James I Macrae
- Department of Biochemistry and Molecular Biology, Bio21 Institute of Molecular Science and Biotechnology, 30 Flemington Road, Melbourne, Vic., 3010, Australia
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Implication of lateral genetic transfer in the emergence of Aeromonas hydrophila isolates of epidemic outbreaks in channel catfish. PLoS One 2013; 8:e80943. [PMID: 24278351 PMCID: PMC3835674 DOI: 10.1371/journal.pone.0080943] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 10/08/2013] [Indexed: 01/29/2023] Open
Abstract
To investigate the molecular basis of the emergence of Aeromonas hydrophila responsible for an epidemic outbreak of motile aeromonad septicemia of catfish in the Southeastern United States, we sequenced 11 A. hydrophila isolates that includes five reference and six recent epidemic isolates. Comparative genomics revealed that recent epidemic A. hydrophila isolates are highly clonal, whereas reference isolates are greatly diverse. We identified 55 epidemic-associated genetic regions with 313 predicted genes that are present in epidemic isolates but absent from reference isolates and 35% of these regions are located within genomic islands, suggesting their acquisition through lateral gene transfer. The epidemic-associated regions encode predicted prophage elements, pathogenicity islands, metabolic islands, fitness islands and genes of unknown functions, and 34 of the genes encoded in these regions were predicted as virulence factors. We found two pilus biogenesis gene clusters encoded within predicted pathogenicity islands. A functional metabolic island that encodes a complete pathway for myo-inositol catabolism was evident by the ability of epidemic A. hydrophila isolates to use myo-inositol as a sole carbon source. Testing of A. hydrophila field isolates found a consistent correlation between myo-inositol utilization as a sole carbon source and the presence of an epidemic-specific genetic marker. All epidemic isolates and one reference isolate shared a novel O-antigen cluster. Altogether we identified four different O-antigen biosynthesis gene clusters within the 11 sequenced A. hydrophila genomes. Our study reveals new insights into the evolutionary changes that have resulted in the emergence of recent epidemic A. hydrophila strains.
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Fbp1-mediated ubiquitin-proteasome pathway controls Cryptococcus neoformans virulence by regulating fungal intracellular growth in macrophages. Infect Immun 2013; 82:557-68. [PMID: 24478071 DOI: 10.1128/iai.00994-13] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Cryptococcus neoformans is a human fungal pathogen that often causes lung and brain infections in immunocompromised patients, with a high fatality rate. Our previous results showed that an F-box protein, Fbp1, is essential for Cryptococcus virulence independent of the classical virulence factors, suggesting a novel virulence control mechanism. In this study, we show that Fbp1 is part of the ubiquitin-proteasome system, and we further investigated the mechanism of Fbp1 function during infection. Time course studies revealed that the fbp1Δ mutant causes little damage in the infected lung and that the fungal burden in the lung remains at a low but persistent level throughout infection. The fbp1Δ mutant cannot disseminate to other organs following pulmonary infection in the murine inhalation model of cryptococcosis but still causes brain infection in a murine intravenous injection model, suggesting that the block of dissemination of the fbp1Δ mutant is due to its inability to leave the lung. The fbp1Δ mutant showed a defect in intracellular proliferation after phagocytosis in a Cryptococcus-macrophage interaction assay, which likely contributes to its virulence attenuation. To elucidate the molecular basis of the SCF(Fbp1) E3 ligase function, we analyzed potential Fbp1 substrates based on proteomic approaches combined with phenotypic analysis. One substrate, the inositol phosphosphingolipid-phospholipase C1 (Isc1), is required for fungal survival inside macrophage cells, which is consistent with the role of Fbp1 in regulating Cryptococcus-macrophage interaction and fungal virulence. Our results thus reveal a new determinant of fungal virulence that involves the posttranslational regulation of inositol sphingolipid biosynthesis.
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Liu TB, Wang Y, Baker GM, Fahmy H, Jiang L, Xue C. The glucose sensor-like protein Hxs1 is a high-affinity glucose transporter and required for virulence in Cryptococcus neoformans. PLoS One 2013; 8:e64239. [PMID: 23691177 PMCID: PMC3653957 DOI: 10.1371/journal.pone.0064239] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Accepted: 04/08/2013] [Indexed: 01/14/2023] Open
Abstract
Cryptococcus is a major fungal pathogen that frequently causes systemic infection in patients with compromised immunity. Glucose, an important signal molecule and the preferred carbon source for Cryptococcus, plays a critical role in fungal development and virulence. Cryptococcus contains more than 50 genes sharing high sequence homology with hexose transporters in Saccharomyces cerevisiae. However, there is no report on their function in glucose sensing or transport. In this study, we investigated two hexose transporter-like proteins (Hxs1 and Hxs2) in Cryptococcus that share the highest sequence identity with the glucose sensors Snf3 and Rgt2 in S. cerevisiae. The expression of HXS1 is repressed by high glucose, while the HXS2 expression is not regulated by glucose. Functional studies showed that Hxs1 is required for fungal resistance to oxidative stress and fungal virulence. The hxs1Δ mutant exhibited a significant reduction in glucose uptake activity, indicating that Hxs1 is required for glucose uptake. Heterologous expression of Cryptococcus HXS1 rendered the S. cerevisiae mutant lacking all 20 hexose transporters a high glucose uptake activity, demonstrating that Hxs1 functions as a glucose transporter. Heterologous expression of HXS1 in the snf3Δ rgt2Δ double mutant did not complement its growth in YPD medium containing the respiration inhibitor antimycin A, suggesting that Hxs1 may not function as a glucose sensor. Taken together, our results demonstrate that Hxs1 is a high-affinity glucose transporter and required for fungal virulence.
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Affiliation(s)
- Tong-Bao Liu
- Public Health Research Institute Center, University of Medicine and Dentistry of New Jersey, Newark, New Jersey, USA
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Liu TB, Kim JC, Wang Y, Toffaletti DL, Eugenin E, Perfect JR, Kim KJ, Xue C. Brain inositol is a novel stimulator for promoting Cryptococcus penetration of the blood-brain barrier. PLoS Pathog 2013; 9:e1003247. [PMID: 23592982 PMCID: PMC3617100 DOI: 10.1371/journal.ppat.1003247] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 02/01/2013] [Indexed: 11/17/2022] Open
Abstract
Cryptococcus neoformans is the most common cause of fungal meningitis, with high mortality and morbidity. The reason for the frequent occurrence of Cryptococcus infection in the central nervous system (CNS) is poorly understood. The facts that human and animal brains contain abundant inositol and that Cryptococcus has a sophisticated system for the acquisition of inositol from the environment suggests that host inositol utilization may contribute to the development of cryptococcal meningitis. In this study, we found that inositol plays an important role in Cryptococcus traversal across the blood-brain barrier (BBB) both in an in vitro human BBB model and in in vivo animal models. The capacity of inositol to stimulate BBB crossing was dependent upon fungal inositol transporters, indicated by a 70% reduction in transmigration efficiency in mutant strains lacking two major inositol transporters, Itr1a and Itr3c. Upregulation of genes involved in the inositol catabolic pathway was evident in a microarray analysis following inositol treatment. In addition, inositol increased the production of hyaluronic acid in Cryptococcus cells, which is a ligand known to binding host CD44 receptor for their invasion. These studies suggest an inositol-dependent Cryptococcus traversal of the BBB, and support our hypothesis that utilization of host-derived inositol by Cryptococcus contributes to CNS infection. Cryptococcus neoformans is an AIDS-associated human fungal pathogen that annually causes over 1 million cases of meningitis world-wide, and more than 600,000 attributable deaths. Cryptococcus often causes lung and brain infection and is the leading cause of fungal meningitis in immunosuppressed patients. Why Cryptococcus frequently infects the central nervous system to cause fatal meningitis is an unanswered critical question. Our previous studies revealed a sophisticated inositol acquisition system in Cryptococcus that plays a central role in utilizing environmental inositol to complete its sexual cycle. Here we further demonstrate that inositol acquisition is also important for fungal infection in the brain, where abundant inositol is available. We found that inositol promotes the traversal of Cryptococcus across the blood-brain barrier (BBB), and such stimulation is fungal inositol transporter dependent. We also identified the effects of host inositol on fungal cellular functions that contribute to the stimulation of fungal penetration of the BBB. We propose that inositol utilization is a novel virulence factor for CNS cryptococcosis. Our work lays an important foundation for understanding how fungi respond to available host inositol and indicates the impact of host inositol acquisition on the development of cryptococcal meningitis.
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Affiliation(s)
- Tong-Bao Liu
- Public Health Research Institute Center, University of Medicine and Dentistry of New Jersey, Newark, New Jersey, United States of America
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Xue C. Cryptococcus and beyond--inositol utilization and its implications for the emergence of fungal virulence. PLoS Pathog 2012; 8:e1002869. [PMID: 23028304 PMCID: PMC3441655 DOI: 10.1371/journal.ppat.1002869] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Chaoyang Xue
- Public Health Research Institute, University of Medicine and Dentistry of New Jersey, Newark, New Jersey, USA.
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Choi JN, Kim J, Kim J, Jung WH, Lee CH. Influence of iron regulation on the metabolome of Cryptococcus neoformans. PLoS One 2012; 7:e41654. [PMID: 22911836 PMCID: PMC3402442 DOI: 10.1371/journal.pone.0041654] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Accepted: 06/26/2012] [Indexed: 01/10/2023] Open
Abstract
Iron is an essential nutrient for virtually all organisms and acts as a cofactor for many key enzymes of major metabolic pathways. Furthermore, iron plays a critical role in pathogen-host interactions. In this study, we analyzed metabolomic changes associated with iron availability and the iron regulatory protein Cir1 in a human fungal pathogen Cryptococcus neoformans. Our metabolite analysis revealed that Cir1 influences the glycolytic pathway, ergosterol biosynthesis and inositol metabolism, which require numerous iron-dependent enzymes and play important roles in pathogenesis and antifungal sensitivity of the fungus. Moreover, we demonstrated that increased cellular iron content and altered gene expression in the cir1 mutant contributed to metabolite changes. Our study provides a new insight into iron regulation and the role of Cir1 in metabolome of C. neoformans.
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Affiliation(s)
- Jung Nam Choi
- Department of Bioscience and Biotechnology, Konkuk University, Seoul, Republic of Korea
| | - Jeongmi Kim
- Department of Biotechnology, Chung-Ang University, Anseong-Si, Gyeonggi-Do, Republic of Korea
| | - Jiyoung Kim
- Department of Bioscience and Biotechnology, Konkuk University, Seoul, Republic of Korea
| | - Won Hee Jung
- Department of Biotechnology, Chung-Ang University, Anseong-Si, Gyeonggi-Do, Republic of Korea
| | - Choong Hwan Lee
- Department of Bioscience and Biotechnology, Konkuk University, Seoul, Republic of Korea
- * E-mail:
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Abstract
Fungal meningitis is a serious disease caused by a fungal infection of the central nervous system (CNS) mostly in individuals with immune system deficiencies. Fungal meningitis is often fatal without proper treatment, and the mortality rate remains unacceptably high even with antifungal drug interventions. Currently, cryptococcal meningitis is the most common fungal meningitis in HIV-1/AIDS, and its disease mechanism has been extensively studied. The key steps for fungi to infect brain and cause meningitis after establishment of local infection are the dissemination of fungal cells to the bloodstream and invasion through the blood brain barrier to reach the CNS. In this review, we use cryptococcal CNS infection as an example to describe the current molecular understanding of fungal meningitis, including the establishment of the infection, dissemination, and brain invasion. Host and microbial factors that contribute to these infection steps are also discussed.
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Affiliation(s)
- Tong-Bao Liu
- The Public Health Research Institute, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark, NJ, USA
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The casein kinase I protein Cck1 regulates multiple signaling pathways and is essential for cell integrity and fungal virulence in Cryptococcus neoformans. EUKARYOTIC CELL 2011; 10:1455-64. [PMID: 21926330 DOI: 10.1128/ec.05207-11] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Casein kinases regulate a wide range of cellular functions in eukaryotes, including phosphorylation of proteins that are substrates for degradation via the ubiquitin-proteasome system (UPS). Our previous study demonstrated that Fbp1, a component of the SCF(FBP1) E3 ligase complex, was essential for Cryptococcus virulence. Because the Saccharomyces cerevisiae homolog of Fbp1, Grr1, requires casein kinase I (Yck1 and Yck2) to phosphorylate its substrates, we investigated the function of casein kinase I in Cryptococcus neoformans. In this report, we identified a C. neoformans casein kinase I protein homolog, Cck1. Similar to Fbp1, the expression of Cck1 is negatively regulated by glucose and during mating. cck1 null mutants showed significant virulence attenuation in a murine systemic infection model, but Cck1 was dispensable for the development of classical virulence factors (capsule, melanin, and growth at 37°C). cck1 mutants were hypersensitive to SDS treatment, indicating that Cck1 is required for cell integrity. The functional overlap between Cck1 and Fbp1 suggests that Cck1 may be required for the phosphorylation of Fbp1 substrates. Interestingly, the cck1 mutant also showed increased sensitivity to osmotic stress and oxidative stress, suggesting that Cck1 regulates both cell integrity and the cellular stress response. Our results show that Cck1 regulates the phosphorylation of both Mpk1 and Hog1 mitogen-activated protein kinases (MAPKs), demonstrating that Cck1 regulates cell integrity via the Mpk1 pathway and regulates cell adaptation to stresses via the Hog1 pathway. Overall, our study revealed that Cck1 plays important roles in regulating multiple signaling pathways and is required for fungal pathogenicity.
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Dynamics of Cryptococcus neoformans-macrophage interactions reveal that fungal background influences outcome during cryptococcal meningoencephalitis in humans. mBio 2011; 2:mBio.00158-11. [PMID: 21828220 PMCID: PMC3149853 DOI: 10.1128/mbio.00158-11] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Cryptococcosis is a multifaceted fungal infection with variable clinical presentation and outcome. As in many infectious diseases, this variability is commonly assigned to host factors. To investigate whether the diversity of Cryptococcus neoformans clinical (ClinCn) isolates influences the interaction with host cells and the clinical outcome, we developed and validated new quantitative assays using flow cytometry and J774 macrophages. The phenotype of ClinCn-macrophage interactions was determined for 54 ClinCn isolates recovered from cerebrospinal fluids (CSF) from 54 unrelated patients, based on phagocytic index (PI) and 2-h and 48-h intracellular proliferation indexes (IPH2 and IPH48, respectively). Their phenotypes were highly variable. Isolates harboring low PI/low IPH2 and high PI/high IPH2 values were associated with nonsterilization of CSF at week 2 and death at month 3, respectively. A subset of 9 ClinCn isolates with different phenotypes exhibited variable virulence in mice and displayed intramacrophagic expression levels of the LAC1, APP1, VAD1, IPC1, PLB1, and COX1 genes that were highly variable among the isolates and correlated with IPH48. Variation in the expression of virulence factors is thus shown here to depend on not only experimental conditions but also fungal background. These results suggest that, in addition to host factors, the patient’s outcome can be related to fungal determinants. Deciphering the molecular events involved in C. neoformans fate inside host cells is crucial for our understanding of cryptococcosis pathogenesis. Cryptococcus neoformans is a life-threatening human fungal pathogen that is responsible for an estimated 1 million cases of meningitis/year, predominantly in HIV-infected patients. The diversity of infecting isolates is well established, as is the importance of the host factors. Interaction with macrophages is a major step in cryptococcosis pathogenesis. How the diversity of clinical isolates influences macrophages’ interactions and impacts cryptococcosis outcome in humans remains to be elucidated. Using new assays, we uncovered how yeast-macrophage interactions were highly variable among clinical isolates and found an association between specific behaviors and cryptococcosis outcome. In addition, gene expression of some virulence factors and intracellular proliferation were correlated. While many studies have established that virulence factors can be differentially expressed as a function of experimental conditions, our study demonstrates that, under the same experimental conditions, clinical isolates behaved differently, a diversity that could participate in the variable outcome of infection in humans.
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The F-Box protein Fbp1 regulates sexual reproduction and virulence in Cryptococcus neoformans. EUKARYOTIC CELL 2011; 10:791-802. [PMID: 21478432 DOI: 10.1128/ec.00004-11] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Cryptococcus neoformans is the leading cause of fungal meningitis in immunocomprised populations. Although extensive studies have been conducted on signal transduction pathways important for fungal sexual reproduction and virulence, how fungal virulence is regulated during infection is still not understood. In this study, we identified the F-box protein Fbp1, which contains a putative F-box domain and 12 leucine-rich repeats (LRR). Although fbp1 mutants showed normal growth and produced normal major virulence factors, such as melanin and capsule, Fbp1 was found to be essential for fungal virulence, as fbp1 mutants were avirulent in a murine systemic-infection model. Fbp1 is also important for fungal sexual reproduction. Basidiospore production was blocked in bilateral mating between fbp1 mutants, even though normal dikaryotic hyphae were observed during mating. In vitro assays of stress responses revealed that fbp1 mutants are hypersensitive to SDS, but not calcofluor white (CFW) or Congo red, indicating that Fbp1 may regulate cell membrane integrity. Fbp1 physically interacts with Skp1 homologues in both Saccharomyces cerevisiae and C. neoformans via its F-box domain, suggesting it may function as part of an SCF (Skp1, Cullins, F-box proteins) E3 ligase. Overall, our study revealed that the F-box protein Fbp1 is essential for fungal sporulation and virulence in C. neoformans, which likely represents a conserved novel virulence control mechanism that involves the SCF E3 ubiquitin ligase-mediated proteolysis pathway.
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Two major inositol transporters and their role in cryptococcal virulence. EUKARYOTIC CELL 2011; 10:618-28. [PMID: 21398509 DOI: 10.1128/ec.00327-10] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Cryptococcus neoformans is an AIDS-associated human fungal pathogen and the most common cause of fungal meningitis, with a mortality rate over 40% in AIDS patients. Significant advances have been achieved in understanding its disease mechanisms. Yet the underlying mechanism of a high frequency of cryptococcal meningitis remains unclear. The existence of high inositol concentrations in brain and our earlier discovery of a large inositol transporter (ITR) gene family in C. neoformans led us to investigate the potential role of inositol in Cryptococcus-host interactions. In this study, we focus on functional analyses of two major ITR genes to understand their role in virulence of C. neoformans. Our results show that ITR1A and ITR3C are the only two ITR genes among 10 candidates that can complement the growth defect of a Saccharomyces cerevisiae strain lacking inositol transporters. Both S. cerevisiae strains heterologously expressing ITR1A or ITR3C showed high inositol uptake activity, an indication that they are major inositol transporters. Significantly, itr1a itr3c double mutants showed significant virulence attenuation in murine infection models. Mutating both ITR1A and ITR3C in an ino1 mutant background activates the expression of several remaining ITR candidates and does not show more severe virulence attenuation, suggesting that both inositol uptake and biosynthetic pathways are important for inositol acquisition. Overall, our study provides evidence that host inositol and fungal inositol transporters are important for Cryptococcus pathogenicity.
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Abstract
Cryptococcus gattii recently emerged as the causative agent of cryptococcosis in healthy individuals in western North America, despite previous characterization of the fungus as a pathogen in tropical or subtropical regions. As a foundation to study the genetics of virulence in this pathogen, we sequenced the genomes of a strain (WM276) representing the predominant global molecular type (VGI) and a clinical strain (R265) of the major genotype (VGIIa) causing disease in North America. We compared these C. gattii genomes with each other and with the genomes of representative strains of the two varieties of Cryptococcus neoformans that generally cause disease in immunocompromised people. Our comparisons included chromosome alignments, analysis of gene content and gene family evolution, and comparative genome hybridization (CGH). These studies revealed that the genomes of the two representative C. gattii strains (genotypes VGI and VGIIa) are colinear for the majority of chromosomes, with some minor rearrangements. However, multiortholog phylogenetic analysis and an evaluation of gene/sequence conservation support the existence of speciation within the C. gattii complex. More extensive chromosome rearrangements were observed upon comparison of the C. gattii and the C. neoformans genomes. Finally, CGH revealed considerable variation in clinical and environmental isolates as well as changes in chromosome copy numbers in C. gattii isolates displaying fluconazole heteroresistance. Isolates of Cryptococcus gattii are currently causing an outbreak of cryptococcosis in western North America, and most of the cases occurred in the absence of coinfection with HIV. This pattern is therefore in stark contrast to the current global burden of one million annual cases of cryptococcosis, caused by the related species Cryptococcus neoformans, in the HIV/AIDS population. The genome sequences of two outbreak-associated major genotypes of C. gattii reported here provide insights into genome variation within and between cryptococcal species. These sequences also provide a resource to further evaluate the epidemiology of cryptococcal disease and to evaluate the role of pathogen genes in the differential interactions of C. gattii and C. neoformans with immunocompromised and immunocompetent hosts.
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