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Hargett AA, Azurmendi HF, Crawford CJ, Wear MP, Oscarson S, Casadevall A, Freedberg DI. The structure of a C. neoformans polysaccharide motif recognized by protective antibodies: A combined NMR and MD study. Proc Natl Acad Sci U S A 2024; 121:e2315733121. [PMID: 38330012 PMCID: PMC10873606 DOI: 10.1073/pnas.2315733121] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 12/02/2023] [Indexed: 02/10/2024] Open
Abstract
Cryptococcus neoformans is a fungal pathogen responsible for cryptococcosis and cryptococcal meningitis. The C. neoformans' capsular polysaccharide and its shed exopolysaccharide function both as key virulence factors and to protect the fungal cell from phagocytosis. Currently, a glycoconjugate of these polysaccharides is being explored as a vaccine to protect against C. neoformans infection. In this study, NOE and J-coupling values from NMR experiments were consistent with a converged structure of the synthetic decasaccharide, GXM10-Ac3, calculated from MD simulations. GXM10-Ac3 was designed as an extension of glucuronoxylomannan (GXM) polysaccharide motif (M2) which is common in the clinically predominant serotype A strains and is recognized by protective forms of GXM-specific monoclonal antibodies. The M2 motif is a hexasaccharide with a three-residue α-mannan backbone, modified by β-(1→2)-xyloses (Xyl) on the first two mannoses (Man) and a β-(1→2)-glucuronic acid (GlcA) on the third Man. Combined NMR and MD analyses reveal that GXM10-Ac3 adopts an extended structure, with Xyl/GlcA branches alternating sides along the α-mannan backbone. O-acetyl esters also alternate sides and are grouped in pairs. MD analysis of a twelve M2-repeating unit polymer supports the notion that the GXM10-Ac3 structure is uniformly represented throughout the polysaccharide. This derived GXM model displays high flexibility while maintaining a structural identity, yielding insights to further explore intermolecular interactions between polysaccharides, interactions with anti-GXM mAbs, and the cryptococcal polysaccharide architecture.
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Affiliation(s)
- Audra A. Hargett
- Laboratory of Bacterial Polysaccharides, Office of Vaccines Research and Review, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD 20993
| | - Hugo F. Azurmendi
- Laboratory of Bacterial Polysaccharides, Office of Vaccines Research and Review, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD 20993
| | - Conor J. Crawford
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD21205
- Centre for Synthesis and Chemical Biology, University College Dublin, Dublin 4, Ireland
| | - Maggie P. Wear
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD21205
| | - Stefan Oscarson
- Centre for Synthesis and Chemical Biology, University College Dublin, Dublin 4, Ireland
| | - Arturo Casadevall
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD21205
| | - Darón I. Freedberg
- Laboratory of Bacterial Polysaccharides, Office of Vaccines Research and Review, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD 20993
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Hargett AA, Azurmendi HF, Crawford CJ, Wear MP, Oscarson S, Casadevall A, Freedberg DI. The structure of a C. neoformans polysaccharide motif recognized by protective antibodies: A combined NMR and MD study. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.06.556507. [PMID: 37732210 PMCID: PMC10508755 DOI: 10.1101/2023.09.06.556507] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
Cryptococcus neoformans is a fungal pathogen responsible for cryptococcosis and cryptococcal meningitis. The C. neoformans capsular polysaccharide and shed exopolysaccharide functions both as a key virulence factor and to protect the fungal cell from phagocytosis. Currently, a glycoconjugate of these polysaccharides is being explored as a vaccine to protect against C. neoformans infection. In this combined NMR and MD study, experimentally determined NOEs and J-couplings support a structure of the synthetic decasaccharide, GXM10-Ac3, obtained by MD. GXM10-Ac3 was designed as an extension of glucuronoxylomannan (GXM) polysaccharide motif (M2) which is common in the clinically predominant serotype A strains and is recognized by protective forms of GXM-specific monoclonal antibodies. The M2 motif is characterized by a 6-residue α-mannan backbone repeating unit, consisting of a triad of α-(1→3)-mannoses, modified by β-(1→2)-xyloses on the first two mannoses and a β-(1→2)-glucuronic acid on the third mannose. The combined NMR and MD analyses reveal that GXM10-Ac3 adopts an extended structure, with xylose/glucuronic acid branches alternating sides along the α-mannan backbone. O-acetyl esters also alternate sides and are grouped in pairs. MD analysis of a twelve M2-repeating unit polymer supports the notion that the GXM10-Ac3 structure is uniformly represented throughout the polysaccharide. This experimentally consistent GXM model displays high flexibility while maintaining a structural identity, yielding new insights to further explore intermolecular interactions between polysaccharides, interactions with anti-GXM mAbs, and the cryptococcal polysaccharide architecture.
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Affiliation(s)
- Audra A. Hargett
- Laboratory of Bacterial Polysaccharides, Office of Vaccines Research and Review, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, USA
| | - Hugo F. Azurmendi
- Laboratory of Bacterial Polysaccharides, Office of Vaccines Research and Review, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, USA
| | - Conor J. Crawford
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
- Centre for Synthesis and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
- Current address: Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Maggie P. Wear
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Stefan Oscarson
- Centre for Synthesis and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
| | - Arturo Casadevall
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Darόn I. Freedberg
- Laboratory of Bacterial Polysaccharides, Office of Vaccines Research and Review, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, USA
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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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Stempinski PR, Goughenour KD, du Plooy LM, Alspaugh JA, Olszewski MA, Kozubowski L. The Cryptococcus neoformans Flc1 Homologue Controls Calcium Homeostasis and Confers Fungal Pathogenicity in the Infected Hosts. mBio 2022; 13:e0225322. [PMID: 36169198 PMCID: PMC9600462 DOI: 10.1128/mbio.02253-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 09/12/2022] [Indexed: 01/30/2023] Open
Abstract
Cryptococcus neoformans, an opportunistic yeast pathogen, relies on a complex network of stress response pathways that allow for proliferation in the host. In Saccharomyces cerevisiae, stress responses are regulated by integral membrane proteins containing a transient receptor potential (TRP) domain, including the flavin carrier protein 1 (Flc1), which regulates calcium homeostasis and flavin transport. Here, we report that deletion of C. neoformans FLC1 results in cytosolic calcium elevation and increased nuclear content of calcineurin-dependent transcription factor Crz1, which is associated with an aberrant cell wall chitin overaccumulation observed in the flc1Δ mutant. Absence of Flc1 or inhibition of calcineurin with cyclosporine A prevents vacuolar fusion under conditions of combined osmotic and temperature stress, which is reversed in the flc1Δ mutant by the inhibition of TORC1 kinase with rapamycin. Flc1-deficient yeasts exhibit compromised vacuolar fusion under starvation conditions, including conditions that stimulate formation of carbohydrate capsule. Consequently, the flc1Δ mutant fails to proliferate under low nutrient conditions and displays a defect in capsule formation. Consistent with the previously uncharacterized role of Flc1 in vacuolar biogenesis, we find that Flc1 localizes to the vacuole. The flc1Δ mutant presents a survival defect in J774A.1 macrophage cell-line and profound virulence attenuation in both the Galleria mellonella and mouse pulmonary infection models, demonstrating that Flc1 is essential for pathogenicity. Thus, cryptococcal Flc1 functions in calcium homeostasis and links calcineurin and TOR signaling with vacuolar biogenesis to promote survival under conditions associated with vacuolar fusion required for this pathogen's fitness and virulence. IMPORTANCE Cryptococcosis is a highly lethal infection with limited drug choices, most of which are highly toxic or complicated by emerging antifungal resistance. There is a great need for new drug targets that are unique to the fungus. Here, we identify such a potential target, the Flc1 protein, which we show is crucial for C. neoformans stress response and virulence. Importantly, homologues of Flc1 exist in other fungal pathogens, such as Candida albicans and Aspergillus fumigatus, and are poorly conserved in humans, which could translate into wider spectrum therapy associated with minimal toxicity. Thus, Flc1 could be an "Achille's heel" of C. neoformans to be leveraged therapeutically in cryptococcosis and possibly other fungal infections.
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Affiliation(s)
- Piotr R. Stempinski
- Department of Genetics and Biochemistry, Eukaryotic Pathogens Innovation Center (EPIC), Clemson University, Clemson, South Carolina, USA
| | - Kristie D. Goughenour
- LTC Charles S. Kettles VA Medical Center, Ann Arbor, Michigan, USA
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan Medical School
| | - Lukas M. du Plooy
- Departments of Medicine and Molecular Genetics/Microbiology, Duke University Medical Center, Durham, North Carolina, USA
| | - J. Andrew Alspaugh
- Departments of Medicine and Molecular Genetics/Microbiology, Duke University Medical Center, Durham, North Carolina, USA
| | - Michal A. Olszewski
- LTC Charles S. Kettles VA Medical Center, Ann Arbor, Michigan, USA
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan Medical School
| | - Lukasz Kozubowski
- Department of Genetics and Biochemistry, Eukaryotic Pathogens Innovation Center (EPIC), Clemson University, Clemson, South Carolina, USA
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5
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Wang L, Wang Y, Wang F, Zhao M, Gao X, Chen H, Li N, Zhu Q, Liu L, Zhu W, Liu X, Chen Y, Zhou P, Lu Y, Wang K, Zhao W, Liang W. Development and Application of Rapid Clinical Visualization Molecular Diagnostic Technology for Cryptococcus neoformans/ C. gattii Based on Recombinase Polymerase Amplification Combined With a Lateral Flow Strip. Front Cell Infect Microbiol 2022; 11:803798. [PMID: 35096653 PMCID: PMC8790172 DOI: 10.3389/fcimb.2021.803798] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 12/16/2021] [Indexed: 11/13/2022] Open
Abstract
Cryptococcus neoformans (C. neoformans)/C. gattii can easily invade the human central nervous system and cause cryptococcal meningitis (CM). The clinical fatality rate of these fungi is extremely high and causes more than 180,000 deaths worldwide every year. At present, the common clinical identification methods of these fungi are traditional culture methods and Indian ink staining. In addition, enzyme-linked immunosorbent assay (ELISAs), polymerase chain reaction (PCR), real-time quantitative PCR detecting system (qPCR), mass spectrometry, and metagenomic next-generation sequencing (mNGS) have also been applied to detect these fungus. Due to the rapid progress of meningitis caused by C. neoformans/C. gattii infection, there is a desperate need for fast, sensitive, and on-site detection methods to meet the clinical diagnosis. Recombinase polymerase amplification (RPA) is a promising isothermal amplification technique that can compensate for the shortcomings of the above techniques, featuring short reaction time, high specificity, and high sensitivity, thus meeting the demand for in-field detection of C.neoformans/C. gattii. In our study, RPA- lateral flow strip (LFS) was used to amplify the capsule-associated gene, CAP64, of C. neoformans/C. gattii, and the primer-probe design was optimized by introducing base mismatches to obtain a specific and sensitive primer-probe combination for clinical testing, and specificity of the detection system was determined for 26 common clinical pathogens. This system was developed to obtain results in 20 min at an isothermal temperature of 37°C with a lower limit of detection as low as 10 CFU/μL or 1 fg/μL. A total of 487 clinical samples collected from multicenter multiplexes were tested to evaluate the detection performance of the RPA-LFS system, which revealed that the system could specifically detect C. neoformans/C. gattii, meeting the need for rapid, specific, and sensitive detection.
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Affiliation(s)
- Lei Wang
- Department of Central Laboratory, Lianyungang Hospital Affiliated to Jiangsu University, Lianyungang, China.,School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, China
| | - Yan Wang
- Department of Central Laboratory, Lianyungang Hospital Affiliated to Jiangsu University, Lianyungang, China
| | - Fang Wang
- Department of Central Laboratory, Lianyungang Hospital Affiliated to Jiangsu University, Lianyungang, China
| | - Mengdi Zhao
- Department of Materials Science and Engineering, Suzhou University of Science and Technology, Suzhou, China
| | - Xuzhu Gao
- Department of Central Laboratory, Lianyungang Hospital Affiliated to Jiangsu University, Lianyungang, China
| | - Huimin Chen
- Department of Central Laboratory, Lianyungang Hospital Affiliated to Jiangsu University, Lianyungang, China
| | - Na Li
- Lianyungang Second People's Hospital Affiliated to Bengbu Medical College, Lianyungang, China
| | - Qing Zhu
- Lianyungang Hospital Affiliated to Xuzhou Medical University, Lianyungang, China
| | - Lipin Liu
- Lianyungang Hospital Affiliated to Xuzhou Medical University, Lianyungang, China
| | - Wenjun Zhu
- Department of Central Laboratory, Lianyungang Hospital Affiliated to Jiangsu University, Lianyungang, China
| | - Xia Liu
- Department of Central Laboratory, Lianyungang Hospital Affiliated to Jiangsu University, Lianyungang, China
| | - Yujiao Chen
- Department of Central Laboratory, Lianyungang Hospital Affiliated to Jiangsu University, Lianyungang, China
| | - Ping Zhou
- Department of Central Laboratory, Lianyungang Hospital Affiliated to Jiangsu University, Lianyungang, China
| | - Yingzhi Lu
- Department of Central Laboratory, Lianyungang Hospital Affiliated to Jiangsu University, Lianyungang, China
| | - Kun Wang
- Department of Central Laboratory, Lianyungang Hospital Affiliated to Jiangsu University, Lianyungang, China
| | - Weiguo Zhao
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, China
| | - Wei Liang
- Department of Central Laboratory, Lianyungang Hospital Affiliated to Jiangsu University, Lianyungang, China
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7
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Garcia-Ceron D, Bleackley MR, Anderson MA. Fungal Extracellular Vesicles in Pathophysiology. Subcell Biochem 2021; 97:151-177. [PMID: 33779917 DOI: 10.1007/978-3-030-67171-6_7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Fungal pathogens are a concern in medicine and agriculture that has been exacerbated by the emergence of antifungal-resistant varieties that severely threaten human and animal health, as well as food security. This had led to the search for new and sustainable treatments for fungal diseases. Innovative solutions require a deeper understanding of the interactions between fungal pathogens and their hosts, and the key determinants of fungal virulence. Recently, a link has emerged between the release of extracellular vesicles (EVs) and fungal virulence that may contribute to finding new methods for fungal control. Fungal EVs carry pigments, carbohydrates, protein, nucleic acids and other macromolecules with similar functions as those found in EVs from other organisms, however certain fungal features, such as the fungal cell wall, impact EV release and cargo. Fungal EVs modulate immune responses in the host, have a role in cell-cell communication and transport molecules that function in virulence. Understanding the function of fungal EVs will expand our knowledge of host-pathogen interactions and may provide new and specific targets for antifungal drugs and agrichemicals.
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8
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Zhou B, She J, Yang L, Zhu B. Coexistent pulmonary cryptococcal infection and pulmonary sarcoidosis: a case report and literature review. J Int Med Res 2020; 48:300060520903870. [PMID: 32070156 PMCID: PMC7110916 DOI: 10.1177/0300060520903870] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Cryptococcus is an encapsulated, yeast-like fungus commonly responsible for infections in individuals with impaired T cell-mediated immune responses, including those with acquired immune deficiency syndrome or taking immunosuppressive agents such as steroids or cyclosporine. However, pulmonary fungal infection is rare in patients with untreated sarcoidosis. We report a case of coexistent pulmonary cryptococcal infection in a 43-year-old man with pulmonary sarcoidosis in North-western China. The patient was diagnosed with sarcoidosis via right anterior mediastinal lymph node biopsy and lung biopsy by bronchoscopy. He was treated with oral prednisone 25 mg/day and achieved complete remission of all symptoms. However, repeat chest computed tomography examination revealed enlarged nodules in the left lower lobe, but decreased bilateral diffuse small nodules in the lungs. Computed tomography-guided percutaneous lung puncture biopsy revealed cryptococcal infection. This case highlights the need to consider fungal infection in patients with sarcoidosis at initial presentation, irrespective of their use of immunosuppressive medication.
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Affiliation(s)
- Bo Zhou
- Respiratory and Critical Care Medicine, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Jianqing She
- Cardiovascular Department, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Lan Yang
- Respiratory and Critical Care Medicine, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Bo Zhu
- Respiratory and Critical Care Medicine, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
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9
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Hu P, Liu L, Ke W, Tian X, Wang L. A cyclin protein governs the infectious and sexual life cycles of Cryptococcus neoformans. SCIENCE CHINA-LIFE SCIENCES 2020; 64:1336-1345. [PMID: 33165808 DOI: 10.1007/s11427-020-1697-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 04/29/2020] [Indexed: 12/19/2022]
Abstract
Cell cycle is a fundamental process underlying growth and development in evolutionarily diverse organisms, including fungi. In human fungal pathogens, cell cycle control generally determines their life cycles, either in the environment or during infections. Thus, cell cycle components can potentially serve as important targets for the development of antifungal strategy against fungal infections. Here, in Cryptococcus neoformans, the most common cause of fatal fungal meningitis, we show that a previously uncharacterized B-type cyclin named Cbc1 is essential for both its infectious and sexual cycles. We reveal that Cbc1 coordinates various sexual differentiation and molecular processes, including meiosis. Especially, the absence of Cbc1 abolishes formation of sexual spores in C. neoformans, which are presumed infectious particles. Cbc1 is also required for the major Cryptococcus pathogenic attributes. Virulence assessment using the murine model of cryptococcosis revealed that the cbc1 mutant is avirulent. Together, our results provide an important insight into how C. neoformans employs shared cell cycle regulation to coordinate its infectious and sexual cycles, which are considered crucial for virulence evolution and the production of infectious spores.
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Affiliation(s)
- Pengjie Hu
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Linxia Liu
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Weixin Ke
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiuyun Tian
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Linqi Wang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China. .,University of Chinese Academy of Sciences, Beijing, 100049, China.
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10
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Maliehe M, Ntoi MA, Lahiri S, Folorunso OS, Ogundeji AO, Pohl CH, Sebolai OM. Environmental Factors That Contribute to the Maintenance of Cryptococcus neoformans Pathogenesis. Microorganisms 2020; 8:microorganisms8020180. [PMID: 32012843 PMCID: PMC7074686 DOI: 10.3390/microorganisms8020180] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 12/04/2019] [Accepted: 12/11/2019] [Indexed: 02/07/2023] Open
Abstract
The ability of microorganisms to colonise and display an intracellular lifestyle within a host body increases their fitness to survive and avoid extinction. This host–pathogen association drives microbial evolution, as such organisms are under selective pressure and can become more pathogenic. Some of these microorganisms can quickly spread through the environment via transmission. The non-transmittable fungal pathogens, such as Cryptococcus, probably return into the environment upon decomposition of the infected host. This review analyses whether re-entry of the pathogen into the environment causes restoration of its non-pathogenic state or whether environmental factors and parameters assist them in maintaining pathogenesis. Cryptococcus (C.) neoformans is therefore used as a model organism to evaluate the impact of environmental stress factors that aid the survival and pathogenesis of C. neoformans intracellularly and extracellularly.
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11
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Meya DB, Okurut S, Zziwa G, Cose S, Boulware DR, Janoff EN. HIV-Associated Cryptococcal Immune Reconstitution Inflammatory Syndrome Is Associated with Aberrant T Cell Function and Increased Cytokine Responses. J Fungi (Basel) 2019; 5:jof5020042. [PMID: 31126019 PMCID: PMC6616503 DOI: 10.3390/jof5020042] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 04/24/2019] [Accepted: 04/29/2019] [Indexed: 12/11/2022] Open
Abstract
Cryptococcal meningitis remains a significant opportunistic infection among HIV-infected patients, contributing 15-20% of HIV-related mortality. A complication of initiating antiretroviral therapy (ART) following opportunistic infection is immune reconstitution inflammatory syndrome (IRIS). IRIS afflicts 10-30% of HIV-infected patients with cryptococcal meningitis (CM), but its immunopathogenesis is poorly understood. We compared circulating T cell memory subsets and cytokine responses among 17 HIV-infected Ugandans with CM: 11 with and 6 without CM-IRIS. At meningitis diagnosis, stimulation with cryptococcal capsule component, glucuronoxylomannan (GXM) elicited consistently lower frequencies of CD4+ and CD8+ T cell memory subsets expressing intracellular cytokines (IL-2, IFN-γ, and IL-17) among subjects who subsequently developed CM-IRIS. After ART initiation, T cells evolved to show a decreased CD8+ central memory phenotype. At the onset of CM-IRIS, stimulation more frequently generated polyfunctional IL-2+/IL-17+ CD4+ T cells in patients with CM-IRIS. Moreover, CD8+ central and effector memory T cells from CM-IRIS subjects also demonstrated more robust IL-2 responses to antigenic stimulation vs. controls. Thus, ART during CM elicits distinct differences in T cell cytokine production in response to cryptococcal antigens both prior to and during the development of IRIS, suggesting an immunologic foundation for the development of this morbid complication of CM infection.
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Affiliation(s)
- David B Meya
- Infectious Diseases Institute, Makerere University, Kampala P.O. Box 22418, Uganda.
- Department of Medicine, Center for Infectious Diseases and Microbiology Translational Research, University of Minnesota, Minneapolis, MN 55455, USA.
- School of Medicine, College of Health Sciences, Makerere University, Kampala P.O. Box 7072, Uganda.
| | - Samuel Okurut
- Infectious Diseases Institute, Makerere University, Kampala P.O. Box 22418, Uganda.
| | - Godfrey Zziwa
- Research Department, Makerere University Walter Reed Project, Plot 42, Nakasero Road, Kampala P.O. Box 1624, Uganda.
| | - Stephen Cose
- Clinical Research Department, London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, UK.
- MRC/UVRI and LSHTM Uganda Research Unit, Plot 51-59 Nakiwogo Road, Entebbe P.O.Box 49, Uganda.
| | - David R Boulware
- Department of Medicine, Center for Infectious Diseases and Microbiology Translational Research, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Edward N Janoff
- Mucosal and Vaccine Research Program Colorado (MAVRC), University of Colorado, Denver, Aurora, CO 80045, USA.
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12
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Fan CL, Han LT, Jiang ST, Chang AN, Zhou ZY, Liu TB. The Cys 2His 2 zinc finger protein Zfp1 regulates sexual reproduction and virulence in Cryptococcus neoformans. Fungal Genet Biol 2019; 124:59-72. [PMID: 30630094 DOI: 10.1016/j.fgb.2019.01.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 01/03/2019] [Accepted: 01/03/2019] [Indexed: 12/16/2022]
Abstract
Cryptococcus neoformans is a ubiquitous yeast pathogen that often infects the human central nervous system (CNS) to cause meningitis in immunocompromised individuals. Although numerous signaling pathways and factors important for fungal sexual reproduction and virulence have been investigated, their precise mechanism of action remains to be further elucidated. In this study, we identified and characterized a novel zinc finger protein Zfp1 that regulates fungal sexual reproduction and virulence in C. neoformans. qRT-PCR and ZFP1 promoter regulatory activity assays revealed a ubiquitous expression pattern of ZFP1 in all stages during mating. Subcellular localization analysis indicates that Zfp1 is targeted to the cytoplasm of C. neoformans. In vitro assays of stress responses showed that zfp1Δ mutants and the ZFP1 overexpressed strains ZFP1OE are hypersensitive to SDS, but not Congo red, indicating that Zfp1 may regulate cell membrane integrity. Zfp1 is also essential for fungal sexual reproduction because basidiospore production was blocked in bilateral mating between zfp1Δ mutants or ZFP1 overexpressed strains. Fungal nuclei development assay showed that nuclei in the bilateral mating of zfp1Δ mutants or ZFP1 overexpressed strains failed to undergo meiosis after fusion, indicating Zfp1 is important for regulating meiosis during mating. Although zfp1Δ mutants showed normal growth and produced normal major virulence factors, virulence was attenuated in a murine model. Interestingly, we found that the ZFP1 overexpressed strains were avirulent in a murine systemic-infection model. Overall, our study showed that the zinc finger protein Zfp1 is essential for fungal sporulation and virulence in C. neoformans.
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Affiliation(s)
- Cheng-Li Fan
- College of Animal Science and Technology, Southwest University, Chongqing 400715, China; State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China
| | - Lian-Tao Han
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Microsporidia Infection and Prevention, Southwest University, Chongqing 400715, China
| | - Su-Ting Jiang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Microsporidia Infection and Prevention, Southwest University, Chongqing 400715, China
| | - An-Ni Chang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China
| | - Ze-Yang Zhou
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Microsporidia Infection and Prevention, Southwest University, Chongqing 400715, China
| | - Tong-Bao Liu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Microsporidia Infection and Prevention, Southwest University, Chongqing 400715, China.
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de Azevedo MI, Da Silva AS, Ferreiro L, Doleski PH, Tonin AA, Casali EA, Moritz CE, Schirmbeck GH, Cardoso VV, Flores MM, Fighera R, Santurio JM. Serum and brain purine levels in an experimental systemic infection of mice by Cryptococcus neoformans : Purinergic immunomodulatory effects. Microb Pathog 2017; 113:124-128. [DOI: 10.1016/j.micpath.2017.10.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Revised: 10/04/2017] [Accepted: 10/12/2017] [Indexed: 12/20/2022]
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Heat shock protein 90 localizes to the surface and augments virulence factors of Cryptococcus neoformans. PLoS Negl Trop Dis 2017; 11:e0005836. [PMID: 28783748 PMCID: PMC5559104 DOI: 10.1371/journal.pntd.0005836] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 08/16/2017] [Accepted: 07/26/2017] [Indexed: 12/15/2022] Open
Abstract
Background Thermotolerance is an essential attribute for pathogenesis of Cryptococcus as exemplified by the fact that only two species in the genus, which can grow at 37°C, are human pathogens. Species which have other virulence factors including capsule formation and melanisation, but lack the ability to propagate at 37°C are not pathogenic. In another related fungal pathogen, Candida albicans, heat shock protein 90 has been implicated to be a central player in commanding pathogenicity by governing yeast to hyphal transition and drug resistance. Exploring Hsp90 biology in Cryptococcus in context of thermotolerance may thus highlight important regulatory principles of virulence and open new therapeutic avenues. Methodology/Principal findings Hsp90 is involved in regulating thermotolerance in Cryptococcus as indicated by growth hypersensitivity at 37°C upon mild compromise of Hsp90 function relative to 25°C. Biochemical studies revealed a more potent inhibition of ATPase activity by pharmacological inhibitor 17-AAG at 37°C as compared to 25°C. Catalytic efficiency of the protein at 37°C was found to be 6.39×10−5μM-1. Furthermore, indirect immunofluorescence analysis using a specific antibody revealed cell surface localization of Hsp90 via ER Golgi classical secretory pathway. Hsp90 was found to be induced under capsule inducing conditions and Hsp90 inhibition led to decrease in capsular volume. Finally compromising Hsp90 function improved anidulafungin tolerance in Cryptococcus. Conclusions/Significance Our findings highlight that Hsp90 regulates pathogenicity of the fungus by myriad ways. Firstly, it is involved in mediating thermotolerance which implies targeting Hsp90 can abrogate thermotolerance and hence growth of the fungus. Secondly, this study provides the first report of biochemical properties of Hsp90 of a pathogenic fungus. Finally, since Hsp90 is localised at the cell wall, targeting cell surface Hsp90 can represent a novel strategy to combat this lethal infection. Thermotolerance is a pre-requisite for microbes to propagate successfully as human pathogens. In this study, we have investigated the role of Heat shock protein 90 in the pathogenesis and thermotolerance of C. neoformans, an environmental fungus that causes meningoencephalitis in humans. We show that thermotolerance of Cryptococcus critically depends on Hsp90 function as modest inhibition of Hsp90 function, robustly compromised growth of the fungus at 37°C with little effect at 25°C. This observation correlated with the fact that pharmacological inhibitor, 17-AAG also showed a more potent inhibition of ATPase activity of the protein at 37°C as indicated by a lower IC50 as compared to 25°C. Indirect immunofluorescence analysis using an antibody specific to CnHsp90 revealed cell surface localization of Hsp90. BFA sensitivity of such surface localization indicated involvement of ER-Golgi classical secretory pathway for this localization. Furthermore, inhibition of Hsp90 function not only abrogated the natural resistance of C. neoformans to cell wall targeting inhibitors echinocandins but also led to decrease in capsular assembly which is one of the classical virulence determinants of the pathogen. In all, this study provides the first detailed biochemical as well as functional insights into the role of Hsp90 in governing thermotolerance and augmenting virulence factors in C. neoformans.
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Azevedo RVDM, Rizzo J, Rodrigues ML. Virulence Factors as Targets for Anticryptococcal Therapy. J Fungi (Basel) 2016; 2:jof2040029. [PMID: 29376946 PMCID: PMC5715936 DOI: 10.3390/jof2040029] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 11/18/2016] [Accepted: 11/25/2016] [Indexed: 12/24/2022] Open
Abstract
The global mortality due to cryptococcosis caused by Cryptococcus neoformans or C. gattii is unacceptably high. Currently available therapies are decades old and may be impacted by drug resistance. Therefore, the need for more effective antifungal drugs for cryptococcosis is evident. A number of Cryptococcus virulence factors have been studied in detail, providing crucial information about the fungal biology and putative molecular targets for antifungals. This review focuses on the use of well-described virulence factors of Cryptococcus as potential anticryptococcal agents.
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Affiliation(s)
- Renata V D M Azevedo
- Fundação Oswaldo Cruz-Fiocruz, Centro de Desenvolvimento Tecnológico em Saúde (CDTS), 21040-361 Rio de Janeiro, Brazil.
| | - Juliana Rizzo
- Instituto de Microbiologia Paulo de Góes (IMPG), Universidade Federal do Rio de Janeiro, 21941-902 Rio de Janeiro, Brazil.
- Instituto de Bioquímica Médica (IBqM), Universidade Federal do Rio de Janeiro, 21941-902 Rio de Janeiro, Brazil.
| | - Marcio L Rodrigues
- Fundação Oswaldo Cruz-Fiocruz, Centro de Desenvolvimento Tecnológico em Saúde (CDTS), 21040-361 Rio de Janeiro, Brazil.
- Instituto de Microbiologia Paulo de Góes (IMPG), Universidade Federal do Rio de Janeiro, 21941-902 Rio de Janeiro, Brazil.
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Dahal G, Viola RE. Structure of a fungal form of aspartate semialdehyde dehydrogenase from Cryptococcus neoformans. Acta Crystallogr F Struct Biol Commun 2015; 71:1365-71. [PMID: 26527262 PMCID: PMC4631584 DOI: 10.1107/s2053230x15017495] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 09/18/2015] [Indexed: 11/10/2022] Open
Abstract
Aspartate semialdehyde dehydrogenase (ASADH) functions at a critical junction in the aspartate-biosynthetic pathway and represents a valid target for antimicrobial drug design. This enzyme catalyzes the NADPH-dependent reductive dephosphorylation of β-aspartyl phosphate to produce the key intermediate aspartate semialdehyde. Production of this intermediate represents the first committed step in the biosynthesis of the essential amino acids methionine, isoleucine and threonine in fungi, and also the amino acid lysine in bacteria. The structure of a new fungal form of ASADH from Cryptococcus neoformans has been determined to 2.6 Å resolution. The overall structure of CnASADH is similar to those of its bacterial orthologs, but with some critical differences both in biological assembly and in secondary-structural features that can potentially be exploited for the development of species-selective drugs.
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Affiliation(s)
- Gopal Dahal
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, OH 43606, USA
| | - Ronald E. Viola
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, OH 43606, USA
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Abstract
Enzymes play key roles in fungal pathogenesis. Manipulation of enzyme expression or activity can significantly alter the infection process, and enzyme expression profiles can be a hallmark of disease. Hence, enzymes are worthy targets for better understanding pathogenesis and identifying new options for combatting fungal infections. Advances in genomics, proteomics, transcriptomics, and mass spectrometry have enabled the identification and characterization of new fungal enzymes. This review focuses on recent developments in the virulence-associated enzymes from Cryptococcus neoformans. The enzymatic suite of C. neoformans has evolved for environmental survival, but several of these enzymes play a dual role in colonizing the mammalian host. We also discuss new therapeutic and diagnostic strategies that could be based on the underlying enzymology.
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Meya DB, Okurut S, Zziwa G, Rolfes MA, Kelsey M, Cose S, Joloba M, Naluyima P, Palmer BE, Kambugu A, Mayanja-Kizza H, Bohjanen PR, Eller MA, Wahl SM, Boulware DR, Manabe YC, Janoff EN. Cellular immune activation in cerebrospinal fluid from ugandans with cryptococcal meningitis and immune reconstitution inflammatory syndrome. J Infect Dis 2014; 211:1597-606. [PMID: 25492918 PMCID: PMC4407762 DOI: 10.1093/infdis/jiu664] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 11/11/2014] [Indexed: 12/22/2022] Open
Abstract
Background. Human immunodeficiency virus (HIV)-associated cryptococcal meningitis (CM) is characterized by high fungal burden and limited leukocyte trafficking to cerebrospinal fluid (CSF). The immunopathogenesis of CM immune reconstitution inflammatory syndrome (IRIS) after initiation of antiretroviral therapy at the site of infection is poorly understood. Methods. We characterized the lineage and activation status of mononuclear cells in blood and CSF of HIV-infected patients with noncryptococcal meningitis (NCM) (n = 10), those with CM at day 0 (n = 40) or day 14 (n = 21) of antifungal therapy, and those with CM-IRIS (n = 10). Results. At diagnosis, highly activated CD8+ T cells predominated in CSF in both CM and NCM. CM-IRIS was associated with an increasing frequency of CSF CD4+ T cells (increased from 2.2% to 23%; P = .06), a shift in monocyte phenotype from classic to an intermediate/proinflammatory, and increased programmed death ligand 1 expression on natural killer cells (increased from 11.9% to 61.6%, P = .03). CSF cellular responses were distinct from responses in peripheral blood. Conclusions. After CM, T cells in CSF tend to evolve with the development of IRIS, with increasing proportions of activated CD4+ T cells, migration of intermediate monocytes to the CSF, and declining fungal burden. These changes provide insight into IRIS pathogenesis and could be exploited to more effectively treat CM and prevent CM-IRIS.
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Affiliation(s)
- David B Meya
- Infectious Disease Institute School of Medicine, College of Health Sciences Department of Medicine, Center for Infectious Diseases and Microbiology Translational Research, University of Minnesota, Minneapolis
| | - Samuel Okurut
- Makerere University Walter Reed Project, Kampala Uganda
| | - Godfrey Zziwa
- Makerere University Walter Reed Project, Kampala Uganda
| | - Melissa A Rolfes
- Department of Medicine, Center for Infectious Diseases and Microbiology Translational Research, University of Minnesota, Minneapolis
| | - Melander Kelsey
- Mucosal and Vaccine Research Program Colorado, University of Colorado Denver, Aurora Denver Veterans Affairs Medical Center
| | - Steve Cose
- School of Medicine, College of Health Sciences Medical Research Council/Uganda Virus Research Institute Uganda Research Unit on AIDS, Entebbe London School of Hygiene and Tropical Medicine, United Kingdom
| | - Moses Joloba
- School of Biomedical Sciences, Microbiology Department, Makerere University
| | | | - Brent E Palmer
- Mucosal and Vaccine Research Program Colorado, University of Colorado Denver, Aurora
| | - Andrew Kambugu
- Infectious Disease Institute Department of Medicine, Center for Infectious Diseases and Microbiology Translational Research, University of Minnesota, Minneapolis
| | | | - Paul R Bohjanen
- Department of Medicine, Center for Infectious Diseases and Microbiology Translational Research, University of Minnesota, Minneapolis
| | - Michael A Eller
- US Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring Henry M. Jackson Foundation for the Advancement of Military Medicine
| | - Sharon M Wahl
- National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland
| | - David R Boulware
- Department of Medicine, Center for Infectious Diseases and Microbiology Translational Research, University of Minnesota, Minneapolis
| | - Yuka C Manabe
- Infectious Disease Institute Division of Infectious Diseases, Department of Medicine, Johns Hopkins University, Baltimore
| | - Edward N Janoff
- Mucosal and Vaccine Research Program Colorado, University of Colorado Denver, Aurora Denver Veterans Affairs Medical Center
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Albuquerque PC, Fonseca FL, Dutra FF, Bozza MT, Frases S, Casadevall A, Rodrigues ML. Cryptococcus neoformans glucuronoxylomannan fractions of different molecular masses are functionally distinct. Future Microbiol 2014; 9:147-61. [PMID: 24571070 DOI: 10.2217/fmb.13.163] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
AIMS Glucuronoxylomannan (GXM) is the major polysaccharide component of Cryptococcus neoformans. We evaluated in this study whether GXM fractions of different molecular masses were functionally distinct. MATERIALS & METHODS GXM samples isolated from C. neoformans cultures were fractionated to generate polysaccharide preparations differing in molecular mass. These fractions were used in experiments focused on the association of GXM with cell wall components of C. neoformans, as well as on the interaction of the polysaccharide with host cells. RESULTS & CONCLUSION GXM fractions of variable molecular masses bound to the surface of a C. neoformans acapsular mutant in a punctate pattern that is in contrast to the usual annular pattern of surface coating observed when GXM samples containing the full molecular mass range were used. The polysaccharide samples were also significantly different in their ability to stimulate cytokine production by host cells. Our findings indicate that GXM fractions are functionally distinct depending on their mass.
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Affiliation(s)
- Priscila C Albuquerque
- Centro de Desenvolvimento Tecnológico em Saúde, CTDS-Fiocruz. Avenida Brasil 4036, Prédio da Expansão, 8o andar, Sala 814, Rio de Janeiro, RJ, 21040-361, Brazil
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20
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Virulence mechanisms and Cryptococcus neoformans pathogenesis. Fungal Genet Biol 2014; 78:55-8. [PMID: 25256589 DOI: 10.1016/j.fgb.2014.09.004] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 09/12/2014] [Accepted: 09/15/2014] [Indexed: 01/01/2023]
Abstract
The human fungal pathogen Cryptococcus neoformans is able to rapidly and effectively adapt to varying conditions, favoring its survival in the environment and in the infected host. Many microbial phenotypes have been specifically correlated with virulence in this opportunistic pathogen, such as capsule production, melanin formation, and the secretion of various proteins. Additionally, cellular features such as the cell wall and morphogenesis play important roles in the interaction of this fungus with host immune recognition and response pathways. Survival in the face of host stress also requires maintaining RNA/DNA integrity. Additionally, aging and senescence of the fungal cells determines resistance to host-derived stresses. New mechanisms regulating the expression of these virulence-associated phenotypes have been recently explored. Importantly, human clinical studies are now confirming the roles of specific microbial factors in human infections.
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Teixeira PAC, Penha LL, Mendonça-Previato L, Previato JO. Mannoprotein MP84 mediates the adhesion of Cryptococcus neoformans to epithelial lung cells. Front Cell Infect Microbiol 2014; 4:106. [PMID: 25191644 PMCID: PMC4137752 DOI: 10.3389/fcimb.2014.00106] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 07/18/2014] [Indexed: 01/13/2023] Open
Abstract
The capsule is the most important virulence factor of the fungal pathogen Cryptococcus neoformans. This structure consists of highly hydrated polysaccharides, including glucuronoxylomannan (GXM), and galactoxylomannan (GalXM). It is also composed of mannoproteins (MPs) which corresponds to less than 1% of the capsular weight. Despite MPs being the minority and least studied components, four of these molecules with molecular masses of 115, 98, 88, and 84 kDa were identified and characterized as C. neoformans immunoreactive antigens involved in the pathogenesis, and are potential cryptococcosis vaccine candidates. With the aim to describe the adhesive property of MPs, we cloned and expressed the MP84, a mannoprotein with molecular weight of 84 kDa, on Pichia pastoris yeast, and performed interaction assays of C. neoformans with epithelial lung cells, in the presence or absence of capsule components. Two fungal strains, the wild type, NE-241, and a mutant, CAP67, deficient in GXM production, were used throughout this study. The adhesion assays were completed using epithelial lung cells, A549, and human prostate cancer cells, PC3, as a control. We observed that capsulated wild type (NE-241), and acapsular (CAP67) strains adhered significantly to A549 cells, compared with PC3 cells (p < 0.05). GXM inhibits the NE-241 adhesion, but not the CAP67. In contrast, CAP67 adhesion was only inhibited in the presence of MP84. These results demonstrate the involvement of MP in the adhesion of C. neoformans to epithelial lung cells. We conclude that this interaction possibly involves an adhesion-like interaction between MP on the fungal surface and the complementary receptor molecules on the epithelial cells.
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Affiliation(s)
- Pedro A C Teixeira
- Laboratório de Glicobiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro Rio de Janeiro, Brazil
| | - Luciana L Penha
- Laboratório de Glicobiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro Rio de Janeiro, Brazil
| | - Lucia Mendonça-Previato
- Laboratório de Glicobiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro Rio de Janeiro, Brazil
| | - Jose O Previato
- Laboratório de Glicobiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro Rio de Janeiro, Brazil
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Galiza GJ, Silva TM, Caprioli RA, Tochetto C, Rosa FB, Fighera RA, Kommers GD. Características histomorfológicas e histoquímicas determinantes no diagnóstico da criptococose em animais de companhia. PESQUISA VETERINÁRIA BRASILEIRA 2014. [DOI: 10.1590/s0100-736x2014000300011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sete casos de criptococose (seis gatos e um cão) foram estudados para estabelecer as características histomorfológicas e histoquímicas determinantes no diagnóstico histopatológico dessa condição. Os dados complementares relacionados à epidemiologia, aos aspectos clínicos, à localização das lesões e às alterações macroscópicas foram obtidos dos protocolos de necropsias e biópsias. Na histologia, as leveduras foram observadas no interior de macrófagos ou livres no parênquima, associadas à reação inflamatória linfo-histioplasmocítica que variou de escassa a acentuada. Pela técnica de hematoxilina-eosina (HE) as leveduras eram arredondadas, com célula central contendo um núcleo, circundada por um halo claro (cápsula geralmente não corada). As técnicas histoquímicas do ácido periódico de Schiff (PAS), Grocott e Fontana-Masson (FM) foram utilizadas e evidenciaram a parede das células das leveduras. Pelo FM observou-se a melanina presente nessas células. As técnicas do azul Alciano e da mucicarmina de Mayer evidenciaram principalmente a cápsula polissacarídica das leveduras. O diâmetro das células das leveduras variou de 1,67 a 10,00µm e o diâmetro total das leveduras encapsuladas variou entre 4,17 e 34,16µm. Os brotamentos foram melhor visualizados através do PAS e ocorreram em base estreita, de forma única ou múltipla, principalmente em polos opostos das células das leveduras ou formando uma cadeia. O diagnóstico definitivo de criptococose foi estabelecido através do exame histopatológico, baseando-se na morfologia característica do agente (levedura encapsulada) e em suas propriedades tintoriais (histoquímicas), principalmente nos casos em que a cultura micológica não foi realizada.
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Pbx proteins in Cryptococcus neoformans cell wall remodeling and capsule assembly. EUKARYOTIC CELL 2014; 13:560-71. [PMID: 24585882 DOI: 10.1128/ec.00290-13] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The cryptococcal capsule is a critical virulence factor of an important pathogen, but little is known about how it is associated with the cell or released into the environment. Two mutants lacking PBX1 and PBX2 were found to shed reduced amounts of the capsule polysaccharide glucuronoxylomannan (GXM). Nuclear magnetic resonance, composition, and physical analyses showed that the shed material was of normal mass but was slightly enriched in xylose. In contrast to previous reports, this material contained no glucose. Notably, the capsule fibers of pbxΔ mutant cells grown under capsule-inducing conditions were present at a lower than usual density and were loosely attached to the cell wall. Mutant cell walls were also defective, as indicated by phenotypes including abnormal cell morphology, reduced mating filamentation, and altered cell integrity. All observed phenotypes were shared between the two mutants and exacerbated in a double mutant. Consistent with a role in surface glycan synthesis, the Pbx proteins localized to detergent-resistant membrane domains. These results, together with the sequence motifs in the Pbx proteins, suggest that Pbx1 and Pbx2 are redundant proteins that act in remodeling the cell wall to maintain normal cell morphology and precursor availability for other glycan synthetic processes. Their absence results in aberrant cell wall growth and metabolic imbalance, which together impact cell wall and capsule synthesis, cell morphology, and capsule association. The surface changes also lead to increased engulfment by host phagocytes, consistent with the lack of virulence of pbx mutants in animal models.
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Fabri RL, Coimbra ES, Almeida AC, Siqueira EP, Alves TMA, Zani CL, Scio E. Essential oil of Mitracarpus frigidus as a potent source of bioactive compounds. AN ACAD BRAS CIENC 2013. [PMID: 23207707 DOI: 10.1590/s0001-37652012000400021] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In our previous work (Fabri et al. 2009), we showed that different extracts of Mitracarpus frigidus had significant antibacterial, antifungal and leishmanicidal activities. In order to increase our knowledge about this species, this work assesses the chemical composition and the in vitro biological activity of its essential oil. Thus, the essential oil obtained by hydrodistillation of the aerial parts of M. frigidus was analyzed by GC/MS. Among several compounds detected, 11 were identified, being linalool and eugenol acetate the major components. The essential oil exhibited a moderate antibacterial effect against Staphyloccocus aureus, Bacillus cereus, Pseudomonas aeruginosa and Enterobacter cloacae (MIC 250 µg/mL). On the other hand, it showed a strong antifungal effect against Cryptoccocus neoformans (MIC 8 µg/mL) and Candida albicans (MIC 63 µg/mL). Expressive activity against L. major and L. amazonensis promastigote forms with IC50 values of 47.2 and 89.7 µg/mL, respectively, were also observed. In addition, the antioxidant activity was investigated through DPPH radical-scavenging and showed a significative activity with IC50 of 38 µg/mL. The cytotoxicity against Artemia salina was moderate with LC(50) of 88 µg/mL. The results presented here are the first report on the chemical composition and biological properties of M. frigidus essential oil.
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Affiliation(s)
- Rodrigo L Fabri
- Laboratório de Produtos Naturais Bioativos, Departamento de Bioquímica, Instituto de Ciências Biológicas, Universidade Federal de Juiz de Fora, MG, Brasil
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Where do they come from and where do they go: candidates for regulating extracellular vesicle formation in fungi. Int J Mol Sci 2013; 14:9581-603. [PMID: 23644887 PMCID: PMC3676800 DOI: 10.3390/ijms14059581] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Revised: 04/11/2013] [Accepted: 04/17/2013] [Indexed: 01/23/2023] Open
Abstract
In the past few years, extracellular vesicles (EVs) from at least eight fungal species were characterized. EV proteome in four fungal species indicated putative biogenesis pathways and suggested interesting similarities with mammalian exosomes. Moreover, as observed for mammalian exosomes, fungal EVs were demonstrated to be immunologically active. Here we review the seminal and most recent findings related to the production of EVs by fungi. Based on the current literature about secretion of fungal molecules and biogenesis of EVs in eukaryotes, we focus our discussion on a list of cellular proteins with the potential to regulate vesicle biogenesis in the fungi.
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Chae HS, Jang GE, Kim NH, Son HR, Lee JH, Kim SH, Park GN, Jo HJ, Kim JT, Chang KS. Classification of Cryptococcus neoformans and yeast-like fungus isolates from pigeon droppings by colony phenotyping and ITS genotyping and their seasonal variations in Korea. Avian Dis 2012; 56:58-64. [PMID: 22545529 DOI: 10.1637/9703-030711-reg.1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Cryptococcus neoformans (C neoformans) is a frequent cause of invasive fungal disease in immunocompromised human hosts. Ninety-eight samples of pigeon droppings were collected from the pigeon shelters in Seoul, and cultured on birdseed agar (BSA) and Sabouraud dextrose agar (SDA). One hundred yeast-like colonies were selected and identified via phenotype characteristics, such as colony morphology and biochemical characteristics. This was then followed with genotyping via sequencing of the internal transcribed spacer (ITS) region. The colonies were classified into four kinds of colony color types: brown type (BrT), beige type (BeT), pink type (PT), and white type (WT). Numbers of isolated BrT, BeT, PT, and WT colonies were 22 (22%), 30 (30%), 19 (19%), and 39 (39%), respectively. All BrT colonies were identified as C neoformans. BeT were identified as 19 isolates of Cryptococcus laurentii, 10 isolates of Malassezia furfur, and 1 isolate of Cryptococcus uniguttulatus. PT was divided into two colony color types: light-PT (l-PT) and deep-PT (d-PT). Eighteen of l-PT and one of d-PT were identified as Rhodotorula glutinis and Rhodotorula mucilaginosa, respectively. WT were identified as 34 isolates of Cryptococcus guilliermondii, 3 isolates of Cryptococcus zeylanoides, 1 isolate of Cryptococcus sake, and 1 isolate of Stephanoascus ciferrii. Most strains were classified identically with the use of either phenotype or genotyping techniques, but C uniguttulatus and C sake classified by phenotyping were Pseudozyma aphidis and Cryptococcus famata by genotyping. This rapid screening technique of pathogenic yeast-like fungi by only colony characteristics is also expected to be very useful for primary yeast screening. Additionally, we investigated the seasonal variations of C neoformans and other yeast-like fungi from 379 pigeon-dropping samples that were collected from February 2011 to March 2011. We isolated 685 yeast-like fungi from the samples. Almost all C neoformans and yeast-like fungi were isolated in the fall (298 strains, 43.5%) and spring (244 strains, 35.6%). A few yeast-like fungi were isolated in winter (98 strains, 14.3%) and summer (45 strains, 6%). These results would be used as an important indicator related to epidemiology and prevention of pathogenic yeast-like fungi infections transmitted through pigeon droppings.
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Affiliation(s)
- H S Chae
- Seoul Metropolitan Government Research Institute of Public Health & Environment, Yang-Jae dong, Seo-Cho Gu, Seoul 137-131, Republic of Korea
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Debourgogne A, Iriart X, Blanchet D, Veron V, Boukhari R, Nacher M, Carme B, Aznar C. Characteristics and specificities of Cryptococcus infections in French Guiana, 1998–2008. Med Mycol 2011; 49:864-71. [DOI: 10.3109/13693786.2011.584198] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Martins DB, Zanette RA, França RT, Howes F, Azevedo MI, Botton SA, Mazzanti C, Lopes STA, Santurio JM. Massive cryptococcal disseminated infection in an immunocompetent cat. Vet Dermatol 2010; 22:232-4. [PMID: 21182547 DOI: 10.1111/j.1365-3164.2010.00948.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Extracellular vesicles from Cryptococcus neoformans modulate macrophage functions. Infect Immun 2010; 78:1601-9. [PMID: 20145096 DOI: 10.1128/iai.01171-09] [Citation(s) in RCA: 192] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Cryptococcus neoformans and distantly related fungal species release extracellular vesicles that traverse the cell wall and contain a varied assortment of components, some of which have been associated with virulence. Previous studies have suggested that these extracellular vesicles are produced in vitro and during animal infection, but the role of vesicular secretion during the interaction of fungi with host cells remains unknown. In this report, we demonstrate by fluorescence microscopy that mammalian macrophages can incorporate extracellular vesicles produced by C. neoformans. Incubation of cryptococcal vesicles with murine macrophages resulted in increased levels of extracellular tumor necrosis factor alpha (TNF-alpha), interleukin-10 (IL-10), and transforming growth factor beta (TGF-beta). Vesicle preparations also resulted in a dose-dependent stimulation of nitric oxide production by phagocytes, suggesting that vesicle components stimulate macrophages to produce antimicrobial compounds. Treated macrophages were more effective at killing C. neoformans yeast. Our results indicate that the extracellular vesicles of C. neoformans can stimulate macrophage function, apparently activating these phagocytic cells to enhance their antimicrobial activity. These results establish that cryptococcal vesicles are biologically active.
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Moretti ML, Resende MR, Lazéra MDS, Colombo AL, Shikanai-Yasuda MA. [Guidelines in cryptococcosis--2008]. Rev Soc Bras Med Trop 2009; 41:524-44. [PMID: 19009203 DOI: 10.1590/s0037-86822008000500022] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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31
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Nes WD, Zhou W, Ganapathy K, Liu J, Vatsyayan R, Chamala S, Hernandez K, Miranda M. Sterol 24-C-methyltransferase: An enzymatic target for the disruption of ergosterol biosynthesis and homeostasis in Cryptococcus neoformans. Arch Biochem Biophys 2009; 481:210-8. [DOI: 10.1016/j.abb.2008.11.003] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2008] [Revised: 10/30/2008] [Accepted: 11/01/2008] [Indexed: 10/21/2022]
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Atypical biosynthetic properties of a Delta 12/nu+3 desaturase from the model basidiomycete Phanerochaete chrysosporium. Appl Environ Microbiol 2008; 75:1156-64. [PMID: 19088315 DOI: 10.1128/aem.02049-08] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The model white-rot basidiomycete Phanerochaete chrysosporium contains a single integral membrane Delta(12)-desaturase FAD2 related to the endoplasmic reticular plant FAD2 enzymes. The fungal fad2-like gene was cloned and distinguished itself from plant homologs by the presence of four introns and a significantly larger coding region. The coding sequence exhibits ca. 35% sequence identity to plant homologs, with the highest sequence conservation found in the putative catalytic and major structural domains. In vivo activity of the heterologously expressed enzyme favors C(18) substrates with nu+3 regioselectivity, where the site of desaturation is three carbons carboxy-distal to the reference position of a preexisting double bond (nu). Linoleate accumulated to levels in excess of 12% of the total fatty acids upon heterologous expression of P. chrysosporium FAD2 in Saccharomyces cerevisiae. In contrast to the behavior of the plant FAD2 enzymes, this oleate desaturase does not 12-hydroxylate lipids and is the first example whose activity increases at higher temperatures (30 degrees C versus 15 degrees C). Thus, while maintaining the hallmark activity of the fatty acyl Delta(12)-desaturase family, the basidiomycete fad2 genes appear to have evolved substantially from an ancestral desaturase.
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Belluco S, Thibaud JL, Guillot J, Krockenberger MB, Wyers M, Blot S, Colle MA. Spinal cryptococcoma in an immunocompetent cat. J Comp Pathol 2008; 139:246-51. [PMID: 18783789 PMCID: PMC7094615 DOI: 10.1016/j.jcpa.2008.06.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Accepted: 06/23/2008] [Indexed: 10/27/2022]
Abstract
This report describes an unusual case of primary cryptococcoma in the proximal thoracic spinal cord of an 11-year-old immunocompetent cat from a farm on which there were large numbers of pigeons. This animal was referred for examination with progressive paralysis and shown to be free from feline immunodeficiency virus, feline leukaemia virus, feline coronavirus and Toxoplasma gondii. It died 2 months later. At necropsy, the only lesion detected was a malacic area, 4cm in length, in the spinal cord. Histopathological examination of the spinal cord revealed severe granulomatous inflammation associated with large numbers of encapsulated yeast cells. In addition to the granulomatous host response, necrosis, digestion chambers, Gitter cells, spheroids and lymphocytic perivascular cuffs were features of the malacic areas. Immunohistochemistry confirmed the presence of Cryptococcus neoformans var. grubii yeast cells.
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Affiliation(s)
- S Belluco
- Unité d'Anatomie-Pathologique, UMR 703 INRA/ENVN, Ecole Nationale Vétérinaire de Nantes, France
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Lindenberg ADSC, Chang MR, Paniago AMM, Lazéra MDS, Moncada PMF, Bonfim GF, Nogueira SA, Wanke B. Clinical and epidemiological features of 123 cases of cryptococcosis in Mato Grosso do Sul, Brazil. Rev Inst Med Trop Sao Paulo 2008; 50:75-8. [DOI: 10.1590/s0036-46652008000200002] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2007] [Accepted: 02/01/2008] [Indexed: 11/22/2022] Open
Abstract
To identify the clinical and epidemiological profile of cryptococcosis diagnosed at the University Hospital of the Federal University of Mato Grosso do Sul, Brazil, medical records of 123 patients admitted from January 1995 to December 2005 were analyzed. One hundred and four cases (84.5%) had HIV infection, six (4.9%) had other predisposing conditions and 13 (10.6%) were immunocompetent. Male patients predominated (68.3%) and their age ranged from 19 to 69 years (mean: 35.9). Most patients (73.2%) were born and lived lifelong in the state of Mato Grosso do Sul. Involvement of the central nervous system occurred in 103 patients (83.7%) and headache and vomiting were the most frequent symptoms. In 77 cases it was possible to identify the Cryptococcus species: 69 (89.6%) C. neoformans and eight (10.4%) C. gattii. Amphotericin B was the drug of choice for treatment (106/123), followed by fluconazole in 60% of cases. The overall lethality rate was 49.6%, being 51% among the HIV infected patients and 41.2% among the non-HIV infected (p > 0.05). Although cryptococcosis exhibited in our region a similar behavior to that described in the literature, the detection of an important rate of immunocompetent individuals and five C. gattii cryptococcosis in HIV-infected patients is noteworthy.
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Barbosa FM, Daffre S, Maldonado RA, Miranda A, Nimrichter L, Rodrigues ML. Gomesin, a peptide produced by the spiderAcanthoscurria gomesiana, is a potent anticryptococcal agent that acts in synergism with fluconazole. FEMS Microbiol Lett 2007; 274:279-86. [PMID: 17645524 DOI: 10.1111/j.1574-6968.2007.00850.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Gomesin is an 18-residue cysteine-rich antimicrobial peptide produced by hemocytes of the spider Acanthoscurria gomesiana. In the present study, the antifungal properties of gomesin against Cryptococcus neoformans, the etiologic agent of cryptococcosis, were evaluated. Gomesin bound to the cell surface of cryptococci, which resulted in cell death associated with membrane permeabilization. Antifungal concentrations of gomesin were not toxic for human brain cells. Supplementation of cryptococcal cultures with the peptide (1 microM) caused a decrease in capsule expression and rendered fungal cells more susceptible to killing by human brain phagocytes. The possible use of gomesin in combination with fluconazole, a standard antifungal drug, was also evaluated. In association with fluconazole, gomesin concentrations with low antimicrobial activity (0.1-1 microM) inhibited fungal growth and enhanced the antimicrobial activity of brain phagocytes. These results reveal the potential of gomesin to promote inhibition of cryptococcal growth directly or by enhancing the effectiveness of host defenses.
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Affiliation(s)
- Fabiane M Barbosa
- Departamento de Microbiologia Geral, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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36
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Rodrigues ML, Shi L, Barreto-Bergter E, Nimrichter L, Farias SE, Rodrigues EG, Travassos LR, Nosanchuk JD. Monoclonal antibody to fungal glucosylceramide protects mice against lethal Cryptococcus neoformans infection. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2007; 14:1372-6. [PMID: 17715331 PMCID: PMC2168121 DOI: 10.1128/cvi.00202-07] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Glucosylceramides (GlcCer) are involved in the regulation of Cryptococcus neoformans virulence. In the present study, we demonstrate that passive immunization with a monoclonal antibody to GlcCer significantly reduces host inflammation and prolongs the survival of mice lethally infected with C. neoformans, revealing a potential therapeutic strategy to control cryptococcosis.
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Affiliation(s)
- Marcio L Rodrigues
- Instituto de Microbiologia Professor Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-590, Brazil.
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37
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Collopy-Junior I, Esteves FF, Nimrichter L, Rodrigues ML, Alviano CS, Meyer-Fernandes JR. An ectophosphatase activity in Cryptococcus neoformans. FEMS Yeast Res 2006; 6:1010-7. [PMID: 17042750 DOI: 10.1111/j.1567-1364.2006.00105.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
There is increasing evidence in the literature showing that fungal pathogens express biologically active ectoenzymes. The expression of surface phosphatases at the cell surface of Cryptococcus neoformans, the etiologic agent of cryptococcosis, was evaluated in the present study. Different isolates of C. neoformans express ectophosphatase activity, which is not influenced by capsule size or serotype. The cryptococcal enzyme is an acid phosphatase, inhibited by classic inhibitors of ectophosphatases, including ammonium molybdate and sodium salts of fluoride and orthovanadate. Only the inhibition of enzyme activity caused by sodium orthovanadate has been shown to be irreversible. The cryptococcal ectoenzyme is also inhibited by Zn2+ and inorganic phosphate, the final product of reactions catalyzed by phosphatases. The ectophosphatase from C. neoformans efficiently releases phosphate groups from different phosphorylated amino acids, giving a higher rate of phosphate removal when phosphothreonine is used as a substrate. Yeast cells with irreversibly inhibited ectophosphatases are less capable of adhering to animal epithelial cells than fungi fully expressing enzyme activity, suggesting that ectoenzyme expression can contribute to the pathogenesis of C. neoformans.
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Affiliation(s)
- Itallo Collopy-Junior
- Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, CCS, Bloco H, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, RJ, Brazil
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38
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Rodrigues ML, Nimrichter L, Oliveira DL, Frases S, Miranda K, Zaragoza O, Alvarez M, Nakouzi A, Feldmesser M, Casadevall A. Vesicular polysaccharide export in Cryptococcus neoformans is a eukaryotic solution to the problem of fungal trans-cell wall transport. EUKARYOTIC CELL 2006; 6:48-59. [PMID: 17114598 PMCID: PMC1800364 DOI: 10.1128/ec.00318-06] [Citation(s) in RCA: 363] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The mechanisms by which macromolecules are transported through the cell wall of fungi are not known. A central question in the biology of Cryptococcus neoformans, the causative agent of cryptococcosis, is the mechanism by which capsular polysaccharide synthesized inside the cell is exported to the extracellular environment for capsule assembly and release. We demonstrate that C. neoformans produces extracellular vesicles during in vitro growth and animal infection. Vesicular compartments, which are transferred to the extracellular space by cell wall passage, contain glucuronoxylomannan (GXM), a component of the cryptococcal capsule, and key lipids, such as glucosylceramide and sterols. A correlation between GXM-containing vesicles and capsule expression was observed. The results imply a novel mechanism for the release of the major virulence factor of C. neoformans whereby polysaccharide packaged in lipid vesicles crosses the cell wall and the capsule network to reach the extracellular environment.
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Affiliation(s)
- Marcio L Rodrigues
- Laboratório de Estudos Integrados em Bioquímica Microbiana, Instituto de Microbiologia Professor Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941590, Brazil
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Snelgrove RJ, Edwards L, Williams AE, Rae AJ, Hussell T. In the Absence of Reactive Oxygen Species, T Cells Default to a Th1 Phenotype and Mediate Protection against PulmonaryCryptococcus neoformansInfection. THE JOURNAL OF IMMUNOLOGY 2006; 177:5509-16. [PMID: 17015737 DOI: 10.4049/jimmunol.177.8.5509] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
In recent years, the prevalence of invasive fungal infections has increased, attributed mostly to the rising population of immunocompromised individuals. Cryptococcus neoformans has been one of the most devastating, with an estimated 6-8% of AIDS-infected patients succumbing to Cryptococcus-associated meningitis. Reactive oxygen species (ROS) are potent antimicrobial agents but also play a significant role in regulating immune cell phenotype, but cause immunopathology when produced in excess. We now show that mice lacking phagocyte NADPH oxidase have heightened macrophage and Th1 responses and improved pathogen containment within pulmonary granulomatous lesions. Consequently, dissemination of this fungus to the brain is diminished, an effect that is independent of IL-12. Similar results are described using the metalloporphyrin antioxidant manganese(III) tetrakis(N-ethyl pyridinium-2-yl)porphyrin, which also promoted a protective Th1 response and reduced dissemination to the brain. These findings are in sharp contrast to the protective potential of ROS against other fungal pathogens, and highlight the pivotal role that ROS can fulfill in shaping the profile of the host's immune response.
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Affiliation(s)
- Robert J Snelgrove
- Kennedy Institute of Rheumatology, Imperial College London, Hammersmith, London, United Kingdom
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40
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Fortes TO, Alviano DS, Tupinambá G, Padrón TS, Antoniolli AR, Alviano CS, Seldin L. Production of an antimicrobial substance against Cryptococcus neoformans by Paenibacillus brasilensis Sa3 isolated from the rhizosphere of Kalanchoe brasiliensis. Microbiol Res 2006; 163:200-7. [PMID: 16790336 DOI: 10.1016/j.micres.2006.05.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/10/2006] [Indexed: 11/24/2022]
Abstract
An antifungal substance produced by Paenibacillus brasilensis strain Sa3 was preliminary characterized and showed to be stable after treatment with different enzymes and organic solvents and at a wide range of pH, and presented a molecular weight between 3 and 10 kDa. In vitro antagonism of this strain towards Cryptococcus neoformans was investigated by optical and electronic microscopic analyses and a fungicidal effect on C. neoformans was observed. Ultrastructural analysis showed intense changes on the fungus when it was paired cultured with strain Sa3, mainly the detachment of the capsule from the cell wall and the presence of altered organelles in the cytoplasm. This novel antifungal substance produced by P. brasilensis Sa3 may represent a new insight in antifungal therapy mainly against emergent fungi. Also, prospective studies on rhizobacteria of plants as Kalanchoe brasiliensis may offer a potential source for the discovery of bioactive compounds with medical value.
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Affiliation(s)
- Tiago Oliveira Fortes
- Laboratório de Genética Microbiana, Centro de Ciências da Saúde, Instituto de Microbiologia Prof. Paulo de Góes, Universidade Federal do Rio de Janeiro, Bloco I, Ilha do Fundão, CEP 21941-590 Rio de Janeiro, RJ, Brasil
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Barbosa FM, Fonseca FL, Holandino C, Alviano CS, Nimrichter L, Rodrigues ML. Glucuronoxylomannan-mediated interaction of Cryptococcus neoformans with human alveolar cells results in fungal internalization and host cell damage. Microbes Infect 2005; 8:493-502. [PMID: 16293436 DOI: 10.1016/j.micinf.2005.07.027] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2005] [Revised: 07/28/2005] [Accepted: 07/29/2005] [Indexed: 10/25/2022]
Abstract
Infection by Cryptococcus neoformans begins with inhalation of infectious propagules. Fungi reach the lung tissue and interact with epithelial cells in a crucial but poorly understood process. In this study, the interaction of C. neoformans with the human alveolar epithelial cell lineage A549 was investigated, focusing on the relevance of the capsular polysaccharide in this process. The association of encapsulated strains with A549 cells was significantly inhibited by a monoclonal antibody to glucuronoxylomannan (GXM), a major component of the cryptococcal capsule. A purified preparation of GXM produced similar results, suggesting the occurrence of surface receptors for this polysaccharide on the surface of alveolar cells. A549 cells were in fact able to bind soluble GXM, as confirmed by indirect immunofluorescence analysis using the anti-polysaccharide antibody. C. neoformans is internalized after GXM-mediated interaction with A549 cells in a process that culminates with death of host cells. Our results suggest that C. neoformans can use GXM for attachment to alveolar epithelia, allowing the fungus to reach the intracellular environment and damage host cells through still uncharacterized mechanisms.
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Affiliation(s)
- Fabiane M Barbosa
- Laboratório de Estudos Integrados em Bioquímica Microbiana, Instituto de Microbiologia Professor Paulo de Góes, Universidade Federal do Rio de Janeiro, Cidade Universitária, CCS, Bloco I, Ilha do Fundão, Rio de Janeiro, RJ 21941590, Brazil
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42
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Junior IC, Rodrigues ML, Alviano CS, Travassos LR, Meyer-Fernandes JR. Characterization of an ecto-ATPase activity in Cryptococcus neoformans. FEMS Yeast Res 2005; 5:899-907. [PMID: 15951247 DOI: 10.1016/j.femsyr.2005.04.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2005] [Revised: 04/05/2005] [Accepted: 04/18/2005] [Indexed: 11/18/2022] Open
Abstract
Cryptococcus neoformans is the causative agent of pulmonary cryptococcosis and cryptococcal meningoencephalitis, which are major clinical manifestations in immunosuppressed patients. In the present study, a surface ATPase (ecto-ATPase) was identified in C. neoformans yeast cells. Intact yeasts hydrolyzed adenosine-5'-triphosphate (ATP) at a rate of 29.36+/-3.36nmol Pi/hx10(8) cells. In the presence of 5 mM MgCl(2), this activity was enhanced around 70 times, and an apparent K(m) for Mg-ATP corresponding to 0.61mM was determined. Inhibitors of phosphatases, mitochondrial Mg(2+)-ATPases, V-ATPases, Na(+)-ATPases or P-ATPases had no effect on the cryptococcal ATPase, but extracellular impermeant compounds reduced enzyme activity in living cells. ATP was the best substrate for the cryptococcal ecto-enzyme, but it also efficiently hydrolyzed inosine 5'-triphosphate (ITP), cytidine 5'-triphosphate (CTP), guanosine 5'-triphosphate (GTP) and uridine-5'-triphosphate (UTP). In the presence of ATP, C. neoformans became less susceptible to the antifungal action of fluconazole. Our results are indicative of the occurrence of a C. neoformans ecto-ATPase that may have a role in fungal physiology.
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Affiliation(s)
- Itallo Collopy Junior
- Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, CCS, Bloco H, Cidade Universitária, Ilha do Fundão, 21541-590 Rio de Janeiro, RJ, Brazil
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Boyton RJ, Altmann DM, Wright A, Kon OM. Pulmonary Infection with Cryptococcus neoformans in the Face of Underlying Sarcoidosis. Respiration 2005; 74:462-6. [PMID: 16106116 DOI: 10.1159/000087461] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2004] [Accepted: 01/11/2005] [Indexed: 11/19/2022] Open
Abstract
We present a case of limited pulmonary cryptococcal infection following exposure to pigeon excreta in a patient with sarcoidosis. The pathogenicity of Cryptococcus neoformans depends on the interplay between the immune status of the host and the virulence of the infecting strain. It can range from asymptomatic lung colonization in the immunocompetent host to rapidly progressive meningitis in immunocompromised patients. Immunological models of respiratory disease emphasize a distinction between infections associated with immune suppression on the one hand and diseases such as sarcoidosis believed to involve an excessive Th1-mediated immune response on the other. This case exemplifies the complex nature of immunological responses in the lung and highlights the importance of considering the possibility of co-existent fungal infection in individuals with sarcoidosis. Novel immunotherapeutic options for cryptococcal infection are discussed.
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Affiliation(s)
- Rosemary J Boyton
- Lung Immunology Group, Department of Biological Sciences/NHLI, Faculty of Medicine, Imperial College London, London, UK.
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44
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Lian T, Simmer MI, D'Souza CA, Steen BR, Zuyderduyn SD, Jones SJM, Marra MA, Kronstad JW. Iron-regulated transcription and capsule formation in the fungal pathogen Cryptococcus neoformans. Mol Microbiol 2005; 55:1452-72. [PMID: 15720553 DOI: 10.1111/j.1365-2958.2004.04474.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cryptococcus neoformans is the leading cause of fungal meningitis in humans. Production of a polysaccharide capsule is a key virulence property for the fungus and capsule synthesis is regulated by iron levels. Given that iron acquisition is an important aspect of virulence for many pathogens, we employed serial analysis of gene expression (SAGE) to examine the transcriptome under iron-limiting and iron-replete conditions. Initially, we demonstrated by SAGE and Northern analysis that iron limitation results in an elevated transcript level for the CAP60 gene that is required for capsule production. We also identified genes encoding putative components for iron transport and homeostasis, including the FTR1 (iron permease) gene, with higher transcript levels in the low-iron condition. An FTR1 disruption mutant grows more slowly than wild-type cells in low-iron medium, and shows delayed growth and altered capsule regulation in iron-replete medium. Iron deprivation also resulted in elevated SAGE tags for putative extracellular mannoproteins and the GPI8 gene encoding a glycosylphosphatidylinositol (GPI) transamidase. The GPI8 gene appears to be essential while disruption of the CIG1 gene encoding a mannoprotein resulted in impaired growth in low-iron medium and altered capsule response to the iron-replete condition. Additionally, we found that iron-replete conditions led to elevated transcripts for genes for iron storage, nitrogen metabolism, glycolysis, mitochondrial function, lipid metabolism and calmodulin-calcineurin signalling. Overall, these studies provide the first view of the C. neoformans transcriptional response to different iron levels.
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Affiliation(s)
- Tianshun Lian
- The Michael Smith Laboratories, Department of Microbiology and Immunology, and Faculty of Agricultural Sciences, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
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Edwards L, Williams AE, Krieg AM, Rae AJ, Snelgrove RJ, Hussell T. Stimulation via Toll-like receptor 9 reduces Cryptococcus neoformans-induced pulmonary inflammation in an IL-12-dependent manner. Eur J Immunol 2005; 35:273-81. [PMID: 15597328 DOI: 10.1002/eji.200425640] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Cytosine-phosphate-guanosine-containing oligodeoxynucleotides (CpG ODN) are important vaccine adjuvants that promote Th1-type immune responses. Cryptococcus neoformans is a serious human pathogen that replicates in the lung but may disseminate systemically leading to meningitis, particularly in immunocompromised individuals. Immunization of susceptible C57BL/6 mice with CpG ODN deviates the immune response from a Th2- toward a Th1-type response following infection with C. neoformans. CpG also induces IL-12, TNF, MCP-1 and macrophage nitric oxide production. CD4(+) and CD8(+) T cells producing IFN-gamma increase in frequency, while those producing IL-5 decrease. More importantly, pulmonary eosinophilia is significantly reduced, an effect that depends on IL-12 and CD8(+) T cells but not NK cells. CpG treatment also reduces the burden of C. neoformans in the lung, an effect that is IL-12-, NK cell- and T cell-independent and probably reflects a direct effect of CpG on pathogen opsonization or an enhancement of macrophage antimicrobial activity. An equivalent beneficial effect is also observed when CpG ODN treatment is delivered during established cryptococcal disease. This is the first study documenting that promotion of lung TLR9 signaling using synthetic agonists enhances host defense. Activation of innate immunity has clear therapeutic potential and may even be beneficial in patients with acquired immune deficiency.
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Affiliation(s)
- Lorna Edwards
- Department of Biological Sciences, Imperial College London, CMMI, London SW7 2AZ, UK
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van de Wetering JK, Coenjaerts FEJ, Vaandrager AB, van Golde LMG, Batenburg JJ. Aggregation of Cryptococcus neoformans by surfactant protein D is inhibited by its capsular component glucuronoxylomannan. Infect Immun 2004; 72:145-53. [PMID: 14688091 PMCID: PMC343972 DOI: 10.1128/iai.72.1.145-153.2004] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cryptococcus neoformans is an opportunistic pathogen invading the immunocompromised host. Infection starts with the inhalation of acapsular or sparsely encapsulated cells, after which capsule synthesis is initiated. The capsule is the main virulence factor of this yeast-like fungus. Pulmonary surfactant protein D (SP-D) is an important component of the local innate defense system. In the present study, interactions of SP-D with intact C. neoformans cells and their isolated capsular components were investigated. Although encapsulated cryptococci were bound, SP-D showed the highest affinity for acapsular C. neoformans. Only acapsular cryptococci were aggregated by SP-D. Furthermore, the cryptococcal capsular components glucuronoxylomannan (GXM) and mannoprotein 1 (MP1) were bound with relatively high affinity, in contrast to GalXM and MP2. Binding as well as aggregation of acapsular C. neoformans by SP-D could be inhibited by GXM in concentrations that are likely to be present in the lung after infection, suggesting that not only the capsule hampers SP-D function within the innate defense system of the lung but also the secreted capsular component GXM.
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Affiliation(s)
- J K van de Wetering
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Graduate School of Animal Health, Utrecht University, Utrecht, The Netherlands
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Bose I, Reese AJ, Ory JJ, Janbon G, Doering TL. A yeast under cover: the capsule of Cryptococcus neoformans. EUKARYOTIC CELL 2003; 2:655-63. [PMID: 12912884 PMCID: PMC178345 DOI: 10.1128/ec.2.4.655-663.2003] [Citation(s) in RCA: 164] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Indrani Bose
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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Rodrigues ML, dos Reis FCG, Puccia R, Travassos LR, Alviano CS. Cleavage of human fibronectin and other basement membrane-associated proteins by a Cryptococcus neoformans serine proteinase. Microb Pathog 2003; 34:65-71. [PMID: 12623274 DOI: 10.1016/s0882-4010(02)00195-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The interaction between the fungal pathogen Cryptococcus neoformans and human fibronectin (HFN) was examined in this study. Polypeptides from cryptococcal whole homogenates and cell wall with molecular masses of 25 and 35 kDa, respectively reacted with HFN. The relevance of the occurrence of these proteins in intact cells was uncertain, since yeast cells from different strains and serotypes of C. neoformans did not significantly adhere to soluble or solid-phased HFN. In contrast, an exocellular proteolytic activity that cleaves HFN was suggested. Degradation of HFN by culture supernatant fluids was demonstrated by Western blotting using a monoclonal anti-HFN antibody. Several fragments of lower molecular weights were observed which reacted with the antibody. Proteolysis was mediated by a serine protease activity, since HFN cleavage was completely inhibited by phenylmethylsulfonyl fluoride (PMSF), aprotinin, and N-tosyl-L-phenylalanyl chloromethylketone (TPCK), but not by inhibitors of metalo, cysteine, or aspartyl proteases. Similar results were obtained when the fluorogenic peptide carbobenzoxy-phenylalanyl-arginyl-7-amido-4-methylcoumarin (CBZ-Phe-Arg-NHmet-C) was used as substrate. The cryptococcal supernatant also cleaved laminin and type IV collagen, as demonstrated by polyacrylamide gel electrophoresis with co-polymerized proteins. The hydrolysis of these proteins was mediated by a single cryptococcal protease with a molecular mass of 75 kDa. The cleavage of key host components of the basement membrane and extracellular matrix by C. neoformans may be a relevant factor in the process of fungal invasion.
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Affiliation(s)
- Marcio L Rodrigues
- Departamento de Microbiologia Geral, Instituto de Microbiologia Professor Paulo de Góes, Universidade Federal do Rio de Janeiro, Cidade Universitária, CCS, Bloco G-Ilha do Fundão, Rio de Janeiro, RJ 21941-590, Brazil.
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Mandrioli L, Bettini G, Marcato PS, Benazzi C, Della Salda L, Krockenberger MB, Jensen HE. Central nervous system cryptococcoma in a cat. JOURNAL OF VETERINARY MEDICINE. A, PHYSIOLOGY, PATHOLOGY, CLINICAL MEDICINE 2002; 49:526-30. [PMID: 12549832 DOI: 10.1046/j.1439-0442.2002.00501.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This report describes the gross, histopathological, immunohistochemical and electron microscopic findings in a 4-year-old cat with systemic Cryptococcus neoformans infection. A 1-cm diameter pontine mass, pinpoint lesions in the cerebellum and in the right kidney were the main macroscopic findings. A presumptive diagnosis of cerebral neoplasia with metastasis was formulated. Light microscopy revealed a huge number of yeasts surrounded by a pyogranulomatous inflammatory reaction in the cerebral parenchyma and, to a lesser extent, in the kidney, while the meninges were not involved. The positive mucicarmine stain that coloured the capsule of the yeasts was indicative of cryptococcal infection. Immunohistochemistry confirmed the presence of C. neoformans var. grubii (C. neoformans serotype A). Electron microscopy revealed yeasts with a massive fibrillar capsule and lamellar cell wall free in the cerebral tissue and within macrophages.
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Affiliation(s)
- L Mandrioli
- Department of Veterinary Public Health and Animal Pathology, Faculty of Veterinary Medicine, University of Bologna, Bologna, Italy.
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Lacaz CDS, Heins-Vaccari EM, Hernandez-Arriagada GL, Martins EL, Prearo CAL, Corim SM, Martins MDA. Primary cutaneous cryptococcosis due to Cryptococcus neoformans var. gattii serotype B, in an immunocompetent patient. Rev Inst Med Trop Sao Paulo 2002; 44:225-8. [PMID: 12219115 DOI: 10.1590/s0036-46652002000400008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The authors report a male patient, a seller with no detected immunosuppression, with an extensive ulcerated skin lesion localized on the left forearm, caused by Cryptococcus neoformans var. gattii serotype B. Oral treatment with fluconazole was successful. A review of the literature showed the rarity of this localization in HIV-negative patients. In contrast, skin lesions frequently occurs in HIV-positive patients, with Cryptococcus neoformans var. neoformans serotype A predominating as the etiological agent. In this paper, the pathogenicity of C. neoformans to skin lesions in patients immunocompromised or not, is discussed, showing the efficacy of fluconazole for the treatment of these processes.
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Affiliation(s)
- Carlos da Silva Lacaz
- Laboratório de Micologia Médica, Instituto de Medicina Tropical de São Paulo, São Paulo, Brazil
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