1
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Kwon S, Choi Y, Kim ES, Lee KT, Bahn YS, Jung KW. Pleiotropic roles of LAMMER kinase, Lkh1 in stress responses and virulence of Cryptococcus neoformans. Front Cell Infect Microbiol 2024; 14:1369301. [PMID: 38774630 PMCID: PMC11106425 DOI: 10.3389/fcimb.2024.1369301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Accepted: 03/27/2024] [Indexed: 05/24/2024] Open
Abstract
Dual-specificity LAMMER kinases are highly evolutionarily conserved in eukaryotes and play pivotal roles in diverse physiological processes, such as growth, differentiation, and stress responses. Although the functions of LAMMER kinase in fungal pathogens in pathogenicity and stress responses have been characterized, its role in Cryptococcus neoformans, a human fungal pathogen and a model yeast of basidiomycetes, remains elusive. In this study, we identified a LKH1 homologous gene and constructed a strain with a deleted LKH1 and a complemented strain. Similar to other fungi, the lkh1Δ mutant showed intrinsic growth defects. We observed that C. neoformans Lkh1 was involved in diverse stress responses, including oxidative stress and cell wall stress. Particularly, Lkh1 regulates DNA damage responses in Rad53-dependent and -independent manners. Furthermore, the absence of LKH1 reduced basidiospore formation. Our observations indicate that Lkh1 becomes hyperphosphorylated upon treatment with rapamycin, a TOR protein inhibitor. Notably, LKH1 deletion led to defects in melanin synthesis and capsule formation. Furthermore, we found that the deletion of LKH1 led to the avirulence of C. neoformans in a systemic cryptococcosis murine model. Taken together, Lkh1 is required for the stress response, sexual differentiation, and virulence of C. neoformans.
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Affiliation(s)
- Sunhak Kwon
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, Jeonbuk, Republic of Korea
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea
| | - Yeseul Choi
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea
| | - Eui-Seong Kim
- Korea Zoonosis Research Institute, Jeonbuk National University, Iksan, Jeonbuk, Republic of Korea
| | - Kyung-Tae Lee
- Korea Zoonosis Research Institute, Jeonbuk National University, Iksan, Jeonbuk, Republic of Korea
| | - Yong-Sun Bahn
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea
| | - Kwang-Woo Jung
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, Jeonbuk, Republic of Korea
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2
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Ma L, Zhang X, Li C, Ma X, Zhao X, Zhao X, Zhang P, Zhu X. A U2 snRNP-specific protein, U2A', is involved in stress response and drug resistance in Cryptococcus deneoformans. Biochimie 2024; 220:179-187. [PMID: 37806618 DOI: 10.1016/j.biochi.2023.10.005] [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] [Received: 03/14/2023] [Revised: 08/14/2023] [Accepted: 10/06/2023] [Indexed: 10/10/2023]
Abstract
The spliceosome, a large complex containing five conserved small ribonucleoprotein particles (snRNPs) U1, U2, U4, U5 and U6, plays important roles in precursor messenger RNA splicing. However, the function and mechanism of the spliceosomal snRNPs have not been thoroughly studied in the pathogenic yeast Cryptococcus deneoformans. In this study, we identified a U2A' homologous protein as a component of the cryptococcal U2 snRNP, which was encoded by the LEA1 gene. Using the "suicide" CRISPR-Cas9 tool, we deleted the LEA1 gene in C. deneoformans JEC21 strain and obtained the disruption mutant lea1Δ. The mutant showed a hypersensitivity to 0.03 % sodium dodecyl sulfate, as well as disordered chitin distribution in cell wall observed with Calcofluor White staining, which collectively illustrated the function of U2A' in maintenance of cell wall integrity. Further examination showed that lea1Δ displayed a decreased tolerance to lower or elevated temperatures, osmotic pressure and oxidative stress. The lea1Δ still exhibited susceptibility to geneticin and 5-flucytosine, and increased resistance to ketoconazole. Even, the mutant had a reduced capsule, and the virulence of lea1Δ in the Galleria mellonella model was decreased. Our results indicate that the U2A'-mediated RNA-processing has a particular role in the processing of gene products involved in response to stresses and virulence.
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Affiliation(s)
- Lan Ma
- Beijing Key Laboratory of Genetic Engineering Drug and Biotechnology, College of Life Sciences, Beijing Normal University, Beijing, 100875, China
| | - Xueqing Zhang
- Beijing Key Laboratory of Genetic Engineering Drug and Biotechnology, College of Life Sciences, Beijing Normal University, Beijing, 100875, China
| | - Chenxi Li
- Beijing Key Laboratory of Genetic Engineering Drug and Biotechnology, College of Life Sciences, Beijing Normal University, Beijing, 100875, China
| | - Xiaoyu Ma
- Beijing Key Laboratory of Genetic Engineering Drug and Biotechnology, College of Life Sciences, Beijing Normal University, Beijing, 100875, China
| | - Xuan Zhao
- Beijing Key Laboratory of Genetic Engineering Drug and Biotechnology, College of Life Sciences, Beijing Normal University, Beijing, 100875, China
| | - Xueru Zhao
- Henan Provincial People's Hospital, Zhengzhou, 450003, China
| | - Ping Zhang
- Beijing Key Laboratory of Genetic Engineering Drug and Biotechnology, College of Life Sciences, Beijing Normal University, Beijing, 100875, China.
| | - Xudong Zhu
- Beijing Key Laboratory of Genetic Engineering Drug and Biotechnology, College of Life Sciences, Beijing Normal University, Beijing, 100875, China.
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3
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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
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4
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Yang YL, Fan YB, Gao L, Zhang C, Gu JL, Pan WH, Fang W. Cryptococcus neoformans Csn1201 Is Associated With Pulmonary Immune Responses and Disseminated Infection. Front Immunol 2022; 13:890258. [PMID: 35720283 PMCID: PMC9201341 DOI: 10.3389/fimmu.2022.890258] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 05/09/2022] [Indexed: 11/21/2022] Open
Abstract
Cryptococcus neoformans is a major etiological agent of fungal meningoencephalitis. The outcome of cryptococcosis depends on the complex interactions between the pathogenic fungus and host immunity. The understanding of how C. neoformans manipulates the host immune response through its pathogenic factors remains incomplete. In this study, we defined the roles of a previously uncharacterized protein, Csn1201, in cryptococcal fitness and host immunity. Use of both inhalational and intravenous mouse models demonstrated that the CSN1201 deletion significantly blocked the pulmonary infection and extrapulmonary dissemination of C. neoformans. The in vivo hypovirulent phenotype of the csn1201Δ mutant was attributed to a combination of multiple factors, including preferential dendritic cell accumulation, enhanced Th1 and Th17 immune responses, decreased intracellular survival inside macrophages, and attenuated blood–brain barrier transcytosis rather than exclusively to pathogenic fitness. The csn1201Δ mutant exhibited decreased tolerance to various stressors in vitro, along with reduced capsule production and enhanced cell wall thickness under host-relevant conditions, indicating that the CSN1201 deletion might promote the exposure of cell wall components and thus induce a protective immune response. Taken together, our results strongly support the importance of cryptococcal Csn1201 in pulmonary immune responses and disseminated infection.
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Affiliation(s)
- Ya-Li Yang
- Department of Dermatology, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China.,Department of Laser and Aesthetic Medicine, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Molecular Medical Mycology, Department of Dermatology and Venereology, Changzheng Hospital, Naval Military Medical University, Shanghai, China
| | - Yi-Bin Fan
- Department of Dermatology, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, China
| | - Lei Gao
- Microscopy Core Facility, Biomedical Research Core Facilities, Westlake University, Hangzhou, China
| | - Chao Zhang
- Shanghai Key Laboratory of Molecular Medical Mycology, Department of Dermatology and Venereology, Changzheng Hospital, Naval Military Medical University, Shanghai, China
| | - Ju-Lin Gu
- Department of Dermatology, Third Affiliated Hospital of Naval Military Medical University, Shanghai, China
| | - Wei-Hua Pan
- Shanghai Key Laboratory of Molecular Medical Mycology, Department of Dermatology and Venereology, Changzheng Hospital, Naval Military Medical University, Shanghai, China
| | - Wei Fang
- Department of Laser and Aesthetic Medicine, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Molecular Medical Mycology, Department of Dermatology and Venereology, Changzheng Hospital, Naval Military Medical University, Shanghai, China
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5
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Simplified All-In-One CRISPR-Cas9 Construction for Efficient Genome Editing in Cryptococcus Species. J Fungi (Basel) 2021; 7:jof7070505. [PMID: 34202664 PMCID: PMC8303259 DOI: 10.3390/jof7070505] [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: 04/28/2021] [Revised: 06/19/2021] [Accepted: 06/22/2021] [Indexed: 11/17/2022] Open
Abstract
Cryptococcus neoformans and Cryptococcus deneoformans are opportunistic fungal pathogens found worldwide that are utilized to reveal mechanisms of fungal pathogenesis. However, their low homologous recombination frequency has greatly encumbered genetic studies. In preliminary work, we described a ‘suicide’ CRISPR-Cas9 system for use in the efficient gene editing of C. deneoformans, but this has not yet been used in the C. neoformans strain. The procedures involved in constructing vectors are time-consuming, whether they involve restriction enzyme-based cloning of donor DNA or the introduction of a target sequence into the gRNA expression cassette via overlap PCR, as are sophisticated, thus impeding their widespread application. Here, we report the optimized and simplified construction method for all-in-one CRISPR-Cas9 vectors that can be used in C. neoformans and C. deneoformans strains respectively, named pNK003 (Genbank: MW938321) and pRH003 (Genbank: KX977486). Taking several gene manipulations as examples, we also demonstrate the accuracy and efficiency of the new simplified all-in-one CRISPR-Cas9 genome editing tools in both Serotype A and Serotype D strains, as well as their ability to eliminate Cas9 and gDNA cassettes after gene editing. We anticipate that the availability of new vectors that can simplify and streamline the technical steps for all-in-one CRISPR-Cas9 construction could accelerate genetic studies of the Cryptococcus species.
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6
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Li H, Li Y, Sun T, Du W, Zhang Z, Li D, Ding C. Integrative Proteome and Acetylome Analyses of Murine Responses to Cryptococcus neoformans Infection. Front Microbiol 2020; 11:575. [PMID: 32362878 PMCID: PMC7181412 DOI: 10.3389/fmicb.2020.00575] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Accepted: 03/16/2020] [Indexed: 01/09/2023] Open
Abstract
Cryptococcus neoformans is a causative agent for pulmonary infection and meningoencephalitis. Understanding the host’s response to C. neoformans infection is critical for developing effective treatment. Even though some have elucidated the host response at the transcriptome level, little is known about how it modulates its defense machinery through the proteome mechanism or how protein posttranslational modification responds to the infection. In this work, we employed a murine infection model and mass spectrometry to systematically determine the proteome and acetylome statuses of lungs and brains in the early stage of infection. To extensively analyze the host response, we integrated the proteome data to the transcriptome results. Critical genes, including genes involved in phagosome, lysosome, and platelet activation are significantly altered in protein and gene expression during infection. In the acetylome analysis, we demonstrated that lung and brain tissues differentially regulate protein acetylation during infection. The three primary groups of proteins altered in acetylation status are histones, proteins involved in glucose and fatty acid metabolism, and proteins from the immune system. These analyses provide an integrative regulation network of the host responding to C. neoformans and shed new light on understanding the host’s regulation mechanism when responding to C. neoformans.
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Affiliation(s)
- Hailong Li
- College of Life and Health Sciences, Northeastern University, Shenyang, China
| | - Yanjian Li
- College of Life and Health Sciences, Northeastern University, Shenyang, China
| | - Tianshu Sun
- Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, China.,Central Research Laboratory, Department of Scientific Research, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
| | - Wei Du
- College of Life and Health Sciences, Northeastern University, Shenyang, China
| | - Zhijie Zhang
- Clinical Laboratory, Shengjing Hospital of China Medical University, Shenyang, China
| | - Dancheng Li
- Software College, Northeastern University, Shenyang, China
| | - Chen Ding
- College of Life and Health Sciences, Northeastern University, Shenyang, China.,Key Laboratory of Data Analytics and Optimization for Smart Industry, Northeastern University, Shenyang, China
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7
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Walsh TJ, McCarthy MW. The expanding use of matrix-assisted laser desorption/ionization-time of flight mass spectroscopy in the diagnosis of patients with mycotic diseases. Expert Rev Mol Diagn 2019; 19:241-248. [PMID: 30682890 DOI: 10.1080/14737159.2019.1574572] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
INTRODUCTION Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has emerged as a powerful new tool to identify human fungal pathogens and has radically altered the diagnostic mycology workflow at many medical centers around the world. Areas covered: While most experience is with the identification of yeasts, including species of Candida and Cryptococcus, there is ongoing work investigating the role of MALDI-TOF MS to detect molds, including species of Aspergillus, Fusarium, Scedosporium, and Mucormyctes as well as thermally dimorphic fungi. Expert commentary: In this paper, we review the current knowledge about this important new platform and examine how its expanding use may impact molecular diagnostics and patient care in the years ahead.
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Affiliation(s)
- Thomas J Walsh
- a Transplantation-Oncology Infectious Diseases Program, Departments of Pediatrics, and Microbiology & Immunology , Weill Cornell Medicine , New York , NY , USA
| | - Matthew W McCarthy
- b Division of General Internal Medicine , Weill Cornell Medicine of Cornell University , New York , NY , USA
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8
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Cao W, Jian C, Zhang H, Xu S. Comparison of Clinical Features and Prognostic Factors of Cryptococcal Meningitis Caused by Cryptococcus neoformans in Patients With and Without Pulmonary Nodules. Mycopathologia 2018; 184:73-80. [PMID: 29737452 DOI: 10.1007/s11046-018-0263-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 04/18/2018] [Indexed: 12/22/2022]
Abstract
Whether the clinical features of cryptococcal meningitis (CM) patients vary with the coexistence of pulmonary nodules is not clear. This study aimed to compare the clinical features of CM in patients with and without pulmonary nodules detected by chest computed tomography (CT). The medical records of CM patients hospitalized in Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology from January 1, 2010, to December 31, 2016, were retrospectively reviewed. Baseline demographics, laboratory and radiographic findings, clinical managements, and outcomes were analyzed. A total of 90 CM patients were enrolled. Forty (44.4%) patients had pulmonary nodules (PN-positive), and 50 (55.6%) patients had no pulmonary nodules (PN-negative). Compared with PN-negative patients, PN-positive patients had higher cerebrospinal fluid (CSF)/serum albumin ratios, higher rates of CSF protein > 1000 mg/L, CSF glucose < 2.5 mmol/L, worse overall treatment response, higher rates of abnormal head CT and magnetic resonance imaging manifestations, and more unfavorable clinical outcomes. Multivariate analysis showed that immunocompromise (p = 0.037) and CSF glucose < 2.5 mmol/L (p = 0.044) indicated poor outcome in PN-positive patients, while CSF glucose < 2.5 mmol/L (p = 0.025) also indicated poor outcome in PN-negative patients. Amphotericin B in the initial therapy was a protective factor for PN-negative patients (p = 0.008). Certain clinical features showed significant differences between CM patients with and without pulmonary nodules, and several independent contributing factors impacted the clinical outcomes for CM patients. Future studies should be performed to further examine these factors.
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Affiliation(s)
- Wenhao Cao
- Department of Respiratory and Critical Care Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan, Hubei, 430030, People's Republic of China
| | - Cui Jian
- Department of Clinical Laboratory, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Huojun Zhang
- Department of Respiratory and Critical Care Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan, Hubei, 430030, People's Republic of China
| | - Shuyun Xu
- Department of Respiratory and Critical Care Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan, Hubei, 430030, People's Republic of China.
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9
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Antimicrobial Octapeptin C4 Analogues Active against Cryptococcus Species. Antimicrob Agents Chemother 2018; 62:AAC.00986-17. [PMID: 29158283 PMCID: PMC5786788 DOI: 10.1128/aac.00986-17] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 11/08/2017] [Indexed: 12/31/2022] Open
Abstract
Resistance to antimicrobials is a growing problem in both developed and developing countries. In nations where AIDS is most prevalent, the human fungal pathogen Cryptococcus neoformans is a significant contributor to mortality, and its growing resistance to current antifungals is an ever-expanding threat. We investigated octapeptin C4, from the cationic cyclic lipopeptide class of antimicrobials, as a potential new antifungal. Octapeptin C4 was a potent, selective inhibitor of this fungal pathogen with an MIC of 1.56 μg/ml. Further testing of octapeptin C4 against 40 clinical isolates of C. neoformans var. grubii or neoformans showed an MIC of 1.56 to 3.13 μg/ml, while 20 clinical isolates of C. neoformans var. gattii had an MIC of 0.78 to 12.5 μg/ml. In each case, the MIC values for octapeptin C4 were equivalent to, or better than, current antifungal drugs fluconazole and amphotericin B. The negatively charged polysaccharide capsule of C. neoformans influences the pathogen's sensitivity to octapeptin C4, whereas the degree of melanization had little effect. Testing synthetic octapeptin C4 derivatives provided insight into the structure activity relationships, revealing that the lipophilic amino acid moieties are more important to the activity than the cationic diaminobutyric acid groups. Octapeptins have promising potential for development as anticryptococcal therapeutic agents.
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10
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Arras SDM, Ormerod KL, Erpf PE, Espinosa MI, Carpenter AC, Blundell RD, Stowasser SR, Schulz BL, Tanurdzic M, Fraser JA. Convergent microevolution of Cryptococcus neoformans hypervirulence in the laboratory and the clinic. Sci Rep 2017; 7:17918. [PMID: 29263343 PMCID: PMC5738413 DOI: 10.1038/s41598-017-18106-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 12/05/2017] [Indexed: 12/30/2022] Open
Abstract
Reference strains are a key component of laboratory research, providing a common background allowing for comparisons across a community of researchers. However, laboratory passage of these strains has been shown to lead to reduced fitness and the attenuation of virulence in some species. In this study we show the opposite in the fungal pathogen Cryptococcus neoformans, with analysis of a collection of type strain H99 subcultures revealing that the most commonly used laboratory subcultures belong to a mutant lineage of the type strain that is hypervirulent. The pleiotropic mutant phenotypes in this H99L (for “Laboratory”) lineage are the result of a deletion in the gene encoding the SAGA Associated Factor Sgf29, a mutation that is also present in the widely-used H99L-derived KN99a/α congenic pair. At a molecular level, loss of this gene results in a reduction in histone H3K9 acetylation. Remarkably, analysis of clinical isolates identified loss of function SGF29 mutations in C. neoformans strains infecting two of fourteen patients, demonstrating not only the first example of hypervirulence in clinical C. neoformans samples, but also parallels between in vitro and in vivo microevolution for hypervirulence in this important pathogen.
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Affiliation(s)
- Samantha D M Arras
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia.,School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Kate L Ormerod
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia.,School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Paige E Erpf
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia.,School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Monica I Espinosa
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia.,School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Alex C Carpenter
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia.,School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Ross D Blundell
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia.,School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Samantha R Stowasser
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia.,School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Benjamin L Schulz
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia.,School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Milos Tanurdzic
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - James A Fraser
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia. .,School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia.
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11
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RNA Interference Screening Reveals Host CaMK4 as a Regulator of Cryptococcal Uptake and Pathogenesis. Infect Immun 2017; 85:IAI.00195-17. [PMID: 28970273 DOI: 10.1128/iai.00195-17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 09/25/2017] [Indexed: 12/29/2022] Open
Abstract
Cryptococcus neoformans, the causative agent of cryptococcosis, is an opportunistic fungal pathogen that kills over 200,000 individuals annually. This yeast may grow freely in body fluids, but it also flourishes within host cells. Despite extensive research on cryptococcal pathogenesis, host genes involved in the initial engulfment of fungi and subsequent stages of infection are woefully understudied. To address this issue, we combined short interfering RNA silencing and a high-throughput imaging assay to identify host regulators that specifically influence cryptococcal uptake. Of 868 phosphatase and kinase genes assayed, we discovered 79 whose silencing significantly affected cryptococcal engulfment. For 25 of these, the effects were fungus specific, as opposed to general alterations in phagocytosis. Four members of this group significantly and specifically altered cryptococcal uptake; one of them encoded CaMK4, a calcium/calmodulin-dependent protein kinase. Pharmacological inhibition of CaMK4 recapitulated the observed defects in phagocytosis. Furthermore, mice deficient in CaMK4 showed increased survival compared to wild-type mice upon infection with C. neoformans This increase in survival correlated with decreased expression of pattern recognition receptors on host phagocytes known to recognize C. neoformans Altogether, we have identified a kinase that is involved in C. neoformans internalization by host cells and in host resistance to this deadly infection.
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12
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McCarthy MW, Walsh TJ. The fungal meningitis outbreak five years later: what have we learned about Exserohilum rostratum? EXPERT REVIEW OF PRECISION MEDICINE AND DRUG DEVELOPMENT 2017. [DOI: 10.1080/23808993.2017.1392827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Matthew W. McCarthy
- Medicine, Weill Cornell Medical College, Assistant Attending Physician, Division of General Internal Medicine, New York-Presbyterian Hospital, New York, NY, USA
| | - Thomas J. Walsh
- Transplantation-Oncology Infectious Diseases Program, Chief, Medical Mycology Research Laboratory, Medicine, Pediatrics, and Microbiology & Immunology, Weill Cornell Medical Center, Henry Schueler Foundation Scholar, Sharpe Family Foundation Scholar in Pediatric Infectious Diseases, New York, NY, USA
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13
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McCarthy MW, Kalasauskas D, Petraitis V, Petraitiene R, Walsh TJ. Fungal Infections of the Central Nervous System in Children. J Pediatric Infect Dis Soc 2017; 6:e123-e133. [PMID: 28903523 DOI: 10.1093/jpids/pix059] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 07/04/2017] [Indexed: 01/03/2023]
Abstract
Although uncommon in children, fungal infections of the central nervous system can be devastating and difficult to treat. A better understanding of basic mycologic, immunologic, and pharmacologic processes has led to important advances in the diagnosis and management of these diseases, but their mortality rates remain unacceptably high. In this focused review, we examine the epidemiology and clinical features of the most common fungal pathogens of the central nervous system in children and explore recent advances in diagnosis and antifungal therapy.
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Affiliation(s)
- Matthew W McCarthy
- Division of General Internal Medicine, Weill Cornell Medicine of Cornell University, New York, New York
| | - Darius Kalasauskas
- Department of Neurosurgery, University Medical Center, Johannes Gutenberg University, Mainz, Germany.,Transplantation-Oncology Infectious Diseases Program, Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine of Cornell University, New York, New York
| | - Vidmantas Petraitis
- Transplantation-Oncology Infectious Diseases Program, Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine of Cornell University, New York, New York.,Institute of Infectious Disease and Pathogenic Microbiology, Prienai, Lithuania
| | - Ruta Petraitiene
- Transplantation-Oncology Infectious Diseases Program, Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine of Cornell University, New York, New York.,Institute of Infectious Disease and Pathogenic Microbiology, Prienai, Lithuania
| | - Thomas J Walsh
- Transplantation-Oncology Infectious Diseases Program, Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine of Cornell University, New York, New York.,Departments of Pediatrics, and Microbiology & Immunology, Weill Cornell Medicine of Cornell University, New York, New York
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Arras SDM, Chitty JL, Wizrah MSI, Erpf PE, Schulz BL, Tanurdzic M, Fraser JA. Sirtuins in the phylum Basidiomycota: A role in virulence in Cryptococcus neoformans. Sci Rep 2017; 7:46567. [PMID: 28429797 PMCID: PMC5399365 DOI: 10.1038/srep46567] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 03/17/2017] [Indexed: 02/07/2023] Open
Abstract
Virulence of Cryptococcus neoformans is regulated by a range of transcription factors, and is also influenced by the acquisition of adaptive mutations during infection. Beyond the temporal regulation of virulence factor production by transcription factors and these permanent microevolutionary changes, heritable epigenetic modifications such as histone deacetylation may also play a role during infection. Here we describe the first comprehensive analysis of the sirtuin class of NAD+ dependent histone deacetylases in the phylum Basidiomycota, identifying five sirtuins encoded in the C. neoformans genome. Each sirtuin gene was deleted and a wide range of phenotypic tests performed to gain insight into the potential roles they play. Given the pleiotropic nature of sirtuins in other species, it was surprising that only two of the five deletion strains revealed mutant phenotypes in vitro. However, cryptic consequences of the loss of each sirtuin were identified through whole cell proteomics, and mouse infections revealed a role in virulence for SIR2, HST3 and HST4. The most intriguing phenotype was the repeated inability to complement mutant phenotypes through the reintroduction of the wild-type gene. These data support the model that regulation of sirtuin activity may be employed to enable a drastic alteration of the epigenetic landscape and virulence of C. neoformans.
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Affiliation(s)
- Samantha D M Arras
- Australian Infectious Diseases Research Centre, Queensland, Australia.,School of Chemistry &Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Jessica L Chitty
- Australian Infectious Diseases Research Centre, Queensland, Australia.,School of Chemistry &Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Maha S I Wizrah
- Australian Infectious Diseases Research Centre, Queensland, Australia.,School of Chemistry &Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Paige E Erpf
- Australian Infectious Diseases Research Centre, Queensland, Australia.,School of Chemistry &Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Benjamin L Schulz
- School of Chemistry &Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Milos Tanurdzic
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - James A Fraser
- Australian Infectious Diseases Research Centre, Queensland, Australia.,School of Chemistry &Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
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15
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Chitty JL, Tatzenko TL, Williams SJ, Koh YQAE, Corfield EC, Butler MS, Robertson AAB, Cooper MA, Kappler U, Kobe B, Fraser JA. GMP Synthase Is Required for Virulence Factor Production and Infection by Cryptococcus neoformans. J Biol Chem 2017; 292:3049-3059. [PMID: 28062578 DOI: 10.1074/jbc.m116.767533] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 01/04/2017] [Indexed: 11/06/2022] Open
Abstract
Over the last four decades the HIV pandemic and advances in medical treatments that also cause immunosuppression have produced an ever-growing cohort of individuals susceptible to opportunistic pathogens. Of these, AIDS patients are particularly vulnerable to infection by the encapsulated yeast Cryptococcus neoformans Most commonly found in the environment in purine-rich bird guano, C. neoformans experiences a drastic change in nutrient availability during host infection, ultimately disseminating to colonize the purine-poor central nervous system. Investigating the consequences of this challenge, we have characterized C. neoformans GMP synthase, the second enzyme in the guanylate branch of de novo purine biosynthesis. We show that in the absence of GMP synthase, C. neoformans becomes a guanine auxotroph, the production of key virulence factors is compromised, and the ability to infect nematodes and mice is abolished. Activity assays performed using recombinant protein unveiled differences in substrate binding between the C. neoformans and human enzymes, with structural insights into these kinetic differences acquired via homology modeling. Collectively, these data highlight the potential of GMP synthase to be exploited in the development of new therapeutic agents for the treatment of disseminated, life-threatening fungal infections.
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Affiliation(s)
- Jessica L Chitty
- From the Australian Infectious Diseases Research Centre, School of Chemistry & Molecular Biosciences.,the Institute for Molecular Bioscience, and
| | - Tayla L Tatzenko
- From the Australian Infectious Diseases Research Centre, School of Chemistry & Molecular Biosciences
| | - Simon J Williams
- From the Australian Infectious Diseases Research Centre, School of Chemistry & Molecular Biosciences.,the ANU Research School of Biology, Australian National University, Acton, ACT 2601, Australia
| | - Y Q Andre E Koh
- From the Australian Infectious Diseases Research Centre, School of Chemistry & Molecular Biosciences
| | - Elizabeth C Corfield
- From the Australian Infectious Diseases Research Centre, School of Chemistry & Molecular Biosciences
| | | | | | - Matthew A Cooper
- From the Australian Infectious Diseases Research Centre, School of Chemistry & Molecular Biosciences.,the Institute for Molecular Bioscience, and
| | - Ulrike Kappler
- From the Australian Infectious Diseases Research Centre, School of Chemistry & Molecular Biosciences.,the Centre for Metals in Biology, University of Queensland, St. Lucia, Queensland 4072, Australia and
| | - Bostjan Kobe
- From the Australian Infectious Diseases Research Centre, School of Chemistry & Molecular Biosciences.,the Institute for Molecular Bioscience, and
| | - James A Fraser
- From the Australian Infectious Diseases Research Centre, School of Chemistry & Molecular Biosciences,
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Arras SDM, Chua SMH, Wizrah MSI, Faint JA, Yap AS, Fraser JA. Targeted Genome Editing via CRISPR in the Pathogen Cryptococcus neoformans. PLoS One 2016; 11:e0164322. [PMID: 27711143 PMCID: PMC5053423 DOI: 10.1371/journal.pone.0164322] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 09/22/2016] [Indexed: 12/21/2022] Open
Abstract
Low rates of homologous integration have hindered molecular genetic studies in Cryptococcus neoformans over the past 20 years, and new tools that facilitate genome manipulation in this important pathogen are greatly needed. To this end, we have investigated the use of a Class 2 CRISPR system in C. neoformans (formerly C. neoformans var. grubii). We first expressed a derivative of the Streptococcus pyogenes Cas9 nuclease in C. neoformans, and showed that it has no effect on growth, production of virulence factors in vitro, or virulence in a murine inhalation model. In proof of principle experiments, we tested the CAS9 construct in combination with multiple self-cleaving guide RNAs targeting the well-characterized phosphoribosylaminoamidazole carboxylase-encoding ADE2 gene. Utilizing combinations of transient and stable expression of our constructs, we revealed that functionality of our CRISPR constructs in C. neoformans is dependent upon the CAS9 construct being stably integrated into the genome, whilst transient expression of the guide RNA is sufficient to enhance rates of homologous recombination in the CAS9 genetic background. Given that the presence of the CRISPR nuclease does not influence virulence in a murine inhalation model, we have successfully demonstrated that this system is compatible with studies of C. neoformans pathogenesis and represents a powerful tool that can be exploited by researchers in the field.
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Affiliation(s)
- Samantha D. M. Arras
- Australian Infectious Diseases Research Centre, St Lucia, Queensland, Australia
- School of Chemistry & Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia
| | - Sheena M. H. Chua
- Australian Infectious Diseases Research Centre, St Lucia, Queensland, Australia
- School of Chemistry & Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia
| | - Maha S. I. Wizrah
- Australian Infectious Diseases Research Centre, St Lucia, Queensland, Australia
- School of Chemistry & Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia
| | - Joshua A. Faint
- Australian Infectious Diseases Research Centre, St Lucia, Queensland, Australia
- School of Chemistry & Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia
| | - Amy S. Yap
- Australian Infectious Diseases Research Centre, St Lucia, Queensland, Australia
- School of Chemistry & Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia
| | - James A. Fraser
- Australian Infectious Diseases Research Centre, St Lucia, Queensland, Australia
- School of Chemistry & Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia
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Arras SDM, Fraser JA. Chemical Inhibitors of Non-Homologous End Joining Increase Targeted Construct Integration in Cryptococcus neoformans. PLoS One 2016; 11:e0163049. [PMID: 27643854 PMCID: PMC5028063 DOI: 10.1371/journal.pone.0163049] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 09/01/2016] [Indexed: 11/19/2022] Open
Abstract
The development of a biolistic transformation protocol for Cryptococcus neoformans over 25 years ago ushered in a new era of molecular characterization of virulence in this previously intractable fungal pathogen. However, due to the low rate of homologous recombination in this species, the process of creating targeted gene deletions using biolistic transformation remains inefficient. To overcome the corresponding difficulty achieving molecular genetic modifications, members of the Cryptococcus community have investigated the use of specific genetic backgrounds or construct design strategies aimed at reducing ectopic construct integration via non-homologous end joining (NHEJ). One such approach involves deletion of components of the NHEJ-associated Ku heterodimer. While this strategy increases homologous recombination to nearly 100%, it also restricts strain generation to a ku80Δ genetic background and requires subsequent complex mating procedures to reestablish wild-type DNA repair. In this study, we have investigated the ability of known inhibitors of mammalian NHEJ to transiently phenocopy the C. neoformans Ku deletion strains. Testing of eight candidate inhibitors revealed a range of efficacies in C. neoformans, with the most promising compound (W7) routinely increasing the rate of gene deletion to over 50%. We have successfully employed multiple inhibitors to reproducibly enhance the deletion rate at multiple loci, demonstrating a new, easily applied methodology to expedite acquisition of precise genetic alterations in C. neoformans. Based on this success, we anticipate that the use of these inhibitors will not only become widespread in the Cryptococcus community, but may also find use in other fungal species as well.
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Affiliation(s)
- Samantha D. M. Arras
- Australian Infectious Diseases Research Centre, School of Chemistry & Molecular Biosciences, The University of Queensland, St Lucia, QLD 4072 Australia
| | - James A. Fraser
- Australian Infectious Diseases Research Centre, School of Chemistry & Molecular Biosciences, The University of Queensland, St Lucia, QLD 4072 Australia
- * E-mail:
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Arras SDM, Chitty JL, Blake KL, Schulz BL, Fraser JA. A genomic safe haven for mutant complementation in Cryptococcus neoformans. PLoS One 2015; 10:e0122916. [PMID: 25856300 PMCID: PMC4391909 DOI: 10.1371/journal.pone.0122916] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 02/19/2015] [Indexed: 01/03/2023] Open
Abstract
Just as Koch’s postulates formed the foundation of early infectious disease study, Stanley Falkow’s molecular Koch’s postulates define best practice in determining whether a specific gene contributes to virulence of a pathogen. Fundamentally, these molecular postulates state that if a gene is involved in virulence, its removal will compromise virulence. Likewise, its reintroduction should restore virulence to the mutant. These approaches are widely employed in Cryptococcus neoformans, where gene deletion via biolistic transformation is a well-established technique. However, the complementation of these mutants is less straightforward. Currently, one of three approaches will be taken: the gene is reintroduced at the original locus, the gene is reintroduced into a random site in the genome, or the mutant is not complemented at all. Depending on which approach is utilized, the mutant may be complemented but other genes are potentially disrupted in the process. To counter the drawbacks of the current approaches to complementation we have created a new tool to assist in this key step in the study of a gene’s role in virulence. We have identified and characterized a small gene-free region in the C. neoformans genome dubbed the “safe haven”, and constructed a plasmid vector that targets DNA constructs to this preselected site. The plasmid vector integrates with high frequency, effectively complementing a mutant strain without disrupting adjacent genes. qRT-PCR of the flanking genes on either side of the safe haven site following integration of the targeting vector revealed no changes in their expression, and no secondary phenotypes were observed in a range of phenotypic assays including an intranasal murine infection model. Combined, these data confirm that we have successfully created a much-needed molecular resource for the Cryptococcus community, enabling the reliable fulfillment of the molecular Koch’s postulates.
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Affiliation(s)
- Samantha D. M. Arras
- Australian Infectious Diseases Research Centre and School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Jessica L. Chitty
- Australian Infectious Diseases Research Centre and School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Kirsten L. Blake
- Australian Infectious Diseases Research Centre and School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Benjamin L. Schulz
- Australian Infectious Diseases Research Centre and School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - James A. Fraser
- Australian Infectious Diseases Research Centre and School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
- * E-mail:
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Chitty JL, Fraser JA. Rethinking the targets for antifungal development. MICROBIOLOGY AUSTRALIA 2015. [DOI: 10.1071/ma15028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Datta K, Subramaniam KS. Host Defense Against Cryptococcal Disease: Is There a Role for B Cells and Antibody-Mediated Immunity? CURRENT FUNGAL INFECTION REPORTS 2014. [DOI: 10.1007/s12281-014-0208-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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