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Ueno K, Nagamori A, Honkyu NO, Kataoka M, Shimizu K, Chang YC, Kwon-Chung KJ, Miyazaki Y. Cryptococcus neoformans requires the TVF1 gene for thermotolerance and virulence. Med Mycol 2023; 61:myad101. [PMID: 37818721 PMCID: PMC10565887 DOI: 10.1093/mmy/myad101] [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] [Received: 07/11/2023] [Revised: 09/13/2023] [Accepted: 09/26/2023] [Indexed: 09/29/2023] Open
Abstract
Cryptococcus neoformans is the primary causative agent of cryptococcosis. Since C. neoformans thrives in environments and its optimal growth temperature is 25-30°C, it needs to adapt to heat stress in order to cause infection in mammalian hosts. In this study, we aimed to investigate the role of an uncharacterized gene, CNAG_03308. Although the CNAG_03308 deletion strain grew as well as the parent strain KN99, it produced yeast cells with abnormal morphology at 37°C and failed to propagate at 39°C. Furthermore, the deletion strain exhibited slower growth at 37°C in the presence of congo red, which is a cell wall stressor. When cultured at 39°C, the deletion strain showed strong staining with fluorescent probes for cell wall chitin and chitosan, including FITC-labeled wheat germ agglutinin, Eosin Y, and calcofluor white. The transmission electron microscopy of the deletion strain revealed a thickened inner layer of the cell wall containing chitin and chitosan under heat stress. This cell-surface altered deletion strain induced dendritic cells to secrete more interleukin (IL)-6 and IL-23 than the control strains under heat stress. In a murine infection study, C57BL/6 mice infected with the deletion strain exhibited lower mortality and lower fungal burden in the lungs and brain compared to those infected with the control strains. Based on these findings, we concluded that CNAG_03308 gene is necessary for C. neoformans to adapt to heat stress both in vitro and in the host environment. Therefore, we designated the CNAG_03308 gene as TVF1, which stands for thermotolerance and virulence-related factor 1.
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Affiliation(s)
- Keigo Ueno
- Department of Fungal Infection, National Institute of Infectious Diseases, Tokyo 162-8640, Japan
| | - Akiko Nagamori
- Department of Fungal Infection, National Institute of Infectious Diseases, Tokyo 162-8640, Japan
| | - Nahoko Oniyama Honkyu
- Department of Fungal Infection, National Institute of Infectious Diseases, Tokyo 162-8640, Japan
| | - Michiyo Kataoka
- Department of Pathology, National Institute of Infectious Diseases, Tokyo 162-8640, Japan
| | - Kiminori Shimizu
- Department of Biological Science and Technology, Tokyo University of Science, Tokyo 125-8585, Japan
| | - Yun C Chang
- Molecular Microbiology Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Kyung J Kwon-Chung
- Molecular Microbiology Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Yoshitsugu Miyazaki
- Department of Fungal Infection, National Institute of Infectious Diseases, Tokyo 162-8640, Japan
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Beardsley J, Dao A, Keighley C, Garnham K, Halliday C, Chen SCA, Sorrell TC. What's New in Cryptococcus gattii: From Bench to Bedside and Beyond. J Fungi (Basel) 2022; 9:jof9010041. [PMID: 36675862 PMCID: PMC9865494 DOI: 10.3390/jof9010041] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 12/19/2022] [Accepted: 12/20/2022] [Indexed: 12/29/2022] Open
Abstract
Cryptococcus species are a major cause of life-threatening infections in immunocompromised and immunocompetent hosts. While most disease is caused by Cryptococcus neoformans, Cryptococcus gattii, a genotypically and phenotypically distinct species, is responsible for 11-33% of global cases of cryptococcosis. Despite best treatment, C. gattii infections are associated with early mortality rates of 10-25%. The World Health Organization's recently released Fungal Priority Pathogen List classified C. gattii as a medium-priority pathogen due to the lack of effective therapies and robust clinical and epidemiological data. This narrative review summarizes the latest research on the taxonomy, epidemiology, pathogenesis, laboratory testing, and management of C. gattii infections.
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Affiliation(s)
- Justin Beardsley
- Sydney Infectious Disease Institute, University of Sydney, Sydney, NSW 2145, Australia
- Westmead Hospital, New South Wales Health, Sydney, NSW 2145, Australia
- Westmead Institute for Medical Research, Sydney, NSW 2145, Australia
- Correspondence:
| | - Aiken Dao
- Sydney Infectious Disease Institute, University of Sydney, Sydney, NSW 2145, Australia
- Westmead Hospital, New South Wales Health, Sydney, NSW 2145, Australia
- Westmead Institute for Medical Research, Sydney, NSW 2145, Australia
| | - Caitlin Keighley
- Sydney Infectious Disease Institute, University of Sydney, Sydney, NSW 2145, Australia
| | - Katherine Garnham
- Sydney Infectious Disease Institute, University of Sydney, Sydney, NSW 2145, Australia
- Sunshine Coast University Hospital, Sunshine Coast University, Birtinya, QLD 4575, Australia
| | - Catriona Halliday
- Sydney Infectious Disease Institute, University of Sydney, Sydney, NSW 2145, Australia
- Westmead Hospital, New South Wales Health, Sydney, NSW 2145, Australia
- Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Sydney, NSW 2145, Australia
| | - Sharon C.-A. Chen
- Sydney Infectious Disease Institute, University of Sydney, Sydney, NSW 2145, Australia
- Westmead Hospital, New South Wales Health, Sydney, NSW 2145, Australia
- Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Sydney, NSW 2145, Australia
| | - Tania C. Sorrell
- Sydney Infectious Disease Institute, University of Sydney, Sydney, NSW 2145, Australia
- Westmead Hospital, New South Wales Health, Sydney, NSW 2145, Australia
- Westmead Institute for Medical Research, Sydney, NSW 2145, Australia
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Saidykhan L, Onyishi CU, May RC. The Cryptococcus gattii species complex: Unique pathogenic yeasts with understudied virulence mechanisms. PLoS Negl Trop Dis 2022; 16:e0010916. [PMID: 36520688 PMCID: PMC9754292 DOI: 10.1371/journal.pntd.0010916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Members of Cryptococcus gattii/neoformans species complex are the etiological agents of the potentially fatal human fungal infection cryptococcosis. C. gattii and its sister species cause disease in both immunocompetent and immunocompromised hosts, while the closely related species C. neoformans and C. deneoformans predominantly infect immunocompromised hosts. To date, most studies have focused on similarities in pathogenesis between these two groups, but over recent years, important differences have become apparent. In this review paper, we highlight some of the major phenotypic differences between the C. gattii and neoformans species complexes and justify the need to study the virulence and pathogenicity of the C. gattii species complex as a distinct cryptococcal group.
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Affiliation(s)
- Lamin Saidykhan
- Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
- Division of Physical and Natural Science, University of The Gambia, Brikama Campus, West Coast Region, The Gambia
| | - Chinaemerem U. Onyishi
- Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Robin C. May
- Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
- * E-mail:
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Gene, virulence and related regulatory mechanisms in Cryptococcus gattii. Acta Biochim Biophys Sin (Shanghai) 2022; 54:593-603. [PMID: 35593469 PMCID: PMC9828318 DOI: 10.3724/abbs.2022029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Cryptococcus gattii is a kind of basidiomycetous yeast, which grows in human and animal hosts. C. gattii has four distinct genomes, VGI/AFLP4, VGII/AFLP6, VGIII/AFLP5, and VGIV/AFLP7. The virulence of C. gattii is closely associated with genotype and related stress-signaling pathways, but the pathogenic mechanism of C. gattii has not been fully identified. With the development of genomics and transcriptomics, the relationship among genes, regulatory mechanisms, virulence, and treatment is gradually being recognized. In this review, to better understand how C. gattii causes disease and to characterize hypervirulent C. gattii strains, we summarize the current understanding of C. gattii genotypes, phenotypes, virulence, and the regulatory mechanisms.
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Freitas GJC, Santos DA. Cryptococcus gattii polysaccharide capsule: An insight on fungal-host interactions and vaccine studies. Eur J Immunol 2021; 51:2206-2209. [PMID: 34396521 DOI: 10.1002/eji.202149349] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 07/27/2021] [Indexed: 11/07/2022]
Abstract
Cryptococcus neoformans and C. gattii complexes are the main causative agents of cryptococcosis, a neglected disease with high lethality. The capsule, composed predominantly of the capsular polysaccharide (CP) GXM, is the main virulence factor of this pathogen. The role of CP is well described for C. neoformans and; however, there is a scarcity of studies focused on C. gattii, especially in the context of the fungal-host interaction. Understanding how the immune system recognizes C. gattii can generate meaningful information for diagnosing, preventing, and treating cryptococcosis. In the current issue of the European Journal of Immunology [Eur. J. Immunol. 2021. 51: 2281-2295], Ueno et al. demonstrate that CP inhibits C. gattii recognition by CD11b. In this commentary, we highlight the importance of deeply understanding the role of C. gattii CP during infection and how this knowledge would influence the strategies to develop new vaccines against cryptococcosis.
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Affiliation(s)
- Gustavo J C Freitas
- Departament of Microbiology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Daniel A Santos
- Departament of Microbiology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
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