1
|
Wu S, Song R, Liu T, Li C. Antifungal therapy: Novel drug delivery strategies driven by new targets. Adv Drug Deliv Rev 2023; 199:114967. [PMID: 37336246 DOI: 10.1016/j.addr.2023.114967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 05/22/2023] [Accepted: 06/14/2023] [Indexed: 06/21/2023]
Abstract
In patients with compromised immunity, invasive fungal infections represent a significant cause of mortality. Given the limited availability and drawbacks of existing first-line antifungal drugs, there is a growing interest in exploring novel targets that could facilitate the development of new antifungal agents or enhance the effectiveness of conventional ones. While previous studies have extensively summarized new antifungal targets inherent in fungi for drug development purposes, the exploration of potential targets for novel antifungal drug delivery strategies has received less attention. In this review, we provide an overview of recent advancements in new antifungal drug delivery strategies that leverage novel targets, including those located in the physio-pathological barrier at the site of infection, the infection microenvironment, fungal-host interactions, and the fungal pathogen itself. The objective is to enhance therapeutic efficacy and mitigate toxic effects in fungal infections, particularly in challenging cases such as refractory, recurrent, and drug-resistant invasive fungal infections. We also discuss the current challenges and future prospects associated with target-driven antifungal drug delivery strategies, offering important insights into the clinical implementation of these innovative approaches.
Collapse
Affiliation(s)
- Shuang Wu
- State Key Laboratory of Resource Insects, Medical Research Institute, Southwest University, Chongqing 400716, PR China
| | - Ruiqi Song
- State Key Laboratory of Resource Insects, Medical Research Institute, Southwest University, Chongqing 400716, PR China
| | - Tongbao Liu
- State Key Laboratory of Resource Insects, Medical Research Institute, Southwest University, Chongqing 400716, PR China.
| | - Chong Li
- State Key Laboratory of Resource Insects, Medical Research Institute, Southwest University, Chongqing 400716, PR China; College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, PR China.
| |
Collapse
|
2
|
Denham ST, Brammer B, Chung KY, Wambaugh MA, Bednarek JM, Guo L, Moreau CT, Brown JCS. A dissemination-prone morphotype enhances extrapulmonary organ entry by Cryptococcus neoformans. Cell Host Microbe 2022; 30:1382-1400.e8. [PMID: 36099922 PMCID: PMC9588642 DOI: 10.1016/j.chom.2022.08.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 06/01/2022] [Accepted: 08/18/2022] [Indexed: 01/08/2023]
Abstract
Environmental pathogens move from ecological niches to mammalian hosts, requiring adaptation to dramatically different environments. Microbes that disseminate farther, including the fungal meningitis pathogen Cryptococcus neoformans, require additional adaptation to diverse tissues. We demonstrate that the formation of a small C. neoformans morphotype-called "seed" cells due to their colonizing ability-is critical for extrapulmonary organ entry. Seed cells exhibit changes in fungal cell size and surface expression that result in an enhanced macrophage update. Seed cell formation is triggered by environmental factors, including C. neoformans' environmental niche, and pigeon guano with phosphate plays a central role. Seed cells show the enhanced expression of phosphate acquisition genes, and mutants unable to acquire phosphate fail to adopt the seed cell morphotype. Additionally, phosphate can be released by tissue damage, potentially establishing a feed-forward loop of seed cell formation and dissemination. Thus, C. neoformans' size variation represent inducible morphotypes that change host interactions to facilitate microbe spread.
Collapse
Affiliation(s)
- Steven T Denham
- Division of Microbiology and Immunology, Department of Pathology, University of Utah, Salt Lake City, UT 84112, USA
| | - Brianna Brammer
- Division of Microbiology and Immunology, Department of Pathology, University of Utah, Salt Lake City, UT 84112, USA
| | - Krystal Y Chung
- Division of Microbiology and Immunology, Department of Pathology, University of Utah, Salt Lake City, UT 84112, USA
| | - Morgan A Wambaugh
- Division of Microbiology and Immunology, Department of Pathology, University of Utah, Salt Lake City, UT 84112, USA
| | - Joseph M Bednarek
- Division of Microbiology and Immunology, Department of Pathology, University of Utah, Salt Lake City, UT 84112, USA
| | - Li Guo
- Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112, USA
| | - Christian T Moreau
- Division of Microbiology and Immunology, Department of Pathology, University of Utah, Salt Lake City, UT 84112, USA
| | - Jessica C S Brown
- Division of Microbiology and Immunology, Department of Pathology, University of Utah, Salt Lake City, UT 84112, USA.
| |
Collapse
|
3
|
Rajesh S, Gangadoo S, Nguyen H, Zhai J, Dekiwadia C, Drummond CJ, Chapman J, Truong VK, Tran N. Application of Fluconazole-Loaded pH-Sensitive Lipid Nanoparticles for Enhanced Antifungal Therapy. ACS APPLIED MATERIALS & INTERFACES 2022; 14:32845-32854. [PMID: 35850116 DOI: 10.1021/acsami.2c05165] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Cryptococcus neoformans is a yeast-like fungus that can cause the life-threatening disease cryptococcal meningitis. Numerous reports have shown increased resistance of this fungus against antifungal treatments, such as fluconazole (Fluc), contributing to an 80% global mortality rate. This work presents a novel approach to improve the delivery of the antifungal agent Fluc and increase the drug's targetability and availability at the infection site. Exploiting the acidic environment surrounding a C. neoformans infected site, we have developed pH-sensitive lipid nanoparticles (LNP) encapsulating Fluc to inhibit the growth of resistant C. neoformans. The LNP-Fluc delivery system consists of a neutral lipid monoolein (MO) and a novel synthetic ionizable lipid 2-morpholinoethyl oleate (O2ME). At neutral pH, because of the presence of O2ME, the nanoparticles are neutral and exhibit a liquid crystalline hexagonal nanostructure (hexosomes). At an acidic pH, they are positively charged with a cubic nanostructure (cubosomes), which facilitates the interaction with the negatively charged fungal cell wall. This interaction results in the MIC50 and MIC90 values of the LNP-Fluc being significantly lower than that of the free-Fluc control. Confocal laser scanning microscopy and scanning electron microscopy further support the MIC values, showing fungal cells exposed to LNP-Fluc at acidic pH were heavily distorted, demonstrating efflux of cytoplasmic molecules. In contrast, fungal cells exposed to Fluc alone showed cell walls mostly intact. This current study represents a significant advancement in delivering targeted antifungal therapy to combat fungal antimicrobial resistance.
Collapse
Affiliation(s)
- Sarigama Rajesh
- School of Science, RMIT University, 124 La Trobe St., Melbourne, VIC 3000, Australia
| | - Sheeana Gangadoo
- School of Science, RMIT University, 124 La Trobe St., Melbourne, VIC 3000, Australia
| | - Han Nguyen
- School of Science, RMIT University, 124 La Trobe St., Melbourne, VIC 3000, Australia
| | - Jiali Zhai
- School of Science, RMIT University, 124 La Trobe St., Melbourne, VIC 3000, Australia
| | - Chaitali Dekiwadia
- School of Science, RMIT University, 124 La Trobe St., Melbourne, VIC 3000, Australia
| | - Calum J Drummond
- School of Science, RMIT University, 124 La Trobe St., Melbourne, VIC 3000, Australia
| | - James Chapman
- School of Science, RMIT University, 124 La Trobe St., Melbourne, VIC 3000, Australia
| | - Vi Khanh Truong
- School of Science, RMIT University, 124 La Trobe St., Melbourne, VIC 3000, Australia
- Biomedical Nanoengineering Lab, College of Medicine and Public Health, Flinders University, Bedford Park 5043, South Australia
| | - Nhiem Tran
- School of Science, RMIT University, 124 La Trobe St., Melbourne, VIC 3000, Australia
| |
Collapse
|
4
|
Garcia-Villa M, Gonzalez-Lara A, Rodriguez-Leyva I. Cryptococcal meningitis due to Cryptococcus gattii in an immunocompetent patient: uncommon presentation of a thunderclap headache. BMJ Case Rep 2022; 15:e246158. [PMID: 35379676 PMCID: PMC8981403 DOI: 10.1136/bcr-2021-246158] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/24/2022] [Indexed: 12/30/2022] Open
Abstract
Thunderclap headache is a medical emergency presented as the worst headache ever, is characterised by an abrupt onset and maximal intensity within seconds to minutes. However, cerebrovascular causes are among the most common causes of thunderclap headache, and other non-vascular life-threatening aetiologies should be considered in evaluating a patient. We describe a 23-year-old previously healthy Latino woman who presented to our hospital after a month of repetitive severe, abrupt-onset headaches. Her prior medical history was unremarkable. After a normal brain MRI with angio-MRI, a lumbar puncture was performed with normal opening pressure, hypoglycorrhachia, increased proteins and a leucocyte; India ink staining was positive for encapsulated yeast, cultures were positive for Cryptococcus gattii The patient received appropriate antifungal treatment with a good response. This case highlights the particular presentation of cryptococcal meningitis due to C. gattii among immunocompetent patients.
Collapse
Affiliation(s)
- Marcela Garcia-Villa
- Hospital Star Medica Morelia, Neurology Service, Outpatient Clinic, Morelia Michoacan, Mexico
| | | | - Ildefonso Rodriguez-Leyva
- Neurology, Hospital Central Dr Ignacio Morones Prieto, San Luis Potosi, Mexico
- Neurology Department, Facultad de Medicina, Universidad Autonoma de San Luis Potosi, San Luis Potosi, Mexico
| |
Collapse
|
5
|
Piffer AC, Santos FMD, Thomé MP, Diehl C, Garcia AWA, Kinskovski UP, Schneider RDO, Gerber A, Feltes BC, Schrank A, Vasconcelos ATR, Lenz G, Kmetzsch L, Vainstein MH, Staats CC. Transcriptomic analysis reveals that mTOR pathway can be modulated in macrophage cells by the presence of cryptococcal cells. Genet Mol Biol 2021; 44:e20200390. [PMID: 34352067 PMCID: PMC8341293 DOI: 10.1590/1678-4685-gmb-2020-0390] [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] [Received: 10/21/2020] [Accepted: 05/05/2021] [Indexed: 11/21/2022] Open
Abstract
Cryptococcus neoformans and Cryptococcus gattii are the etiological agents of cryptococcosis, a high mortality disease. The development of such disease depends on the interaction of fungal cells with macrophages, in which they can reside and replicate. In order to dissect the molecular mechanisms by which cryptococcal cells modulate the activity of macrophages, a genome-scale comparative analysis of transcriptional changes in macrophages exposed to Cryptococcus spp. was conducted. Altered expression of nearly 40 genes was detected in macrophages exposed to cryptococcal cells. The major processes were associated with the mTOR pathway, whose associated genes exhibited decreased expression in macrophages incubated with cryptococcal cells. Phosphorylation of p70S6K and GSK-3β was also decreased in macrophages incubated with fungal cells. In this way, Cryptococci presence could drive the modulation of mTOR pathway in macrophages possibly to increase the survival of the pathogen.
Collapse
Affiliation(s)
- Alícia C Piffer
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Porto Alegre, RS, Brazil
| | - Francine M Dos Santos
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Porto Alegre, RS, Brazil
| | - Marcos P Thomé
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Porto Alegre, RS, Brazil
| | - Camila Diehl
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Porto Alegre, RS, Brazil
| | - Ane Wichine Acosta Garcia
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Porto Alegre, RS, Brazil
| | - Uriel Perin Kinskovski
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Porto Alegre, RS, Brazil
| | - Rafael de Oliveira Schneider
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Porto Alegre, RS, Brazil
| | - Alexandra Gerber
- Laboratório Nacional de Computação Científica, Petrópolis, RJ, Brazil
| | - Bruno César Feltes
- Universidade Federal do Rio Grande do Sul, Instituto de Informática, Porto Alegre, RS, Brazil
| | - Augusto Schrank
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Porto Alegre, RS, Brazil
| | | | - Guido Lenz
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Porto Alegre, RS, Brazil
| | - Lívia Kmetzsch
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Porto Alegre, RS, Brazil
| | - Marilene H Vainstein
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Porto Alegre, RS, Brazil
| | - Charley C Staats
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Porto Alegre, RS, Brazil
| |
Collapse
|
6
|
Lev S, Li C, Desmarini D, Liuwantara D, Sorrell TC, Hawthorne WJ, Djordjevic JT. Monitoring Glycolysis and Respiration Highlights Metabolic Inflexibility of Cryptococcus neoformans. Pathogens 2020; 9:pathogens9090684. [PMID: 32839374 PMCID: PMC7559270 DOI: 10.3390/pathogens9090684] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 08/13/2020] [Accepted: 08/20/2020] [Indexed: 12/14/2022] Open
Abstract
Cryptococcus neoformans is a human fungal pathogen that adapts its metabolism to cope with limited oxygen availability, nutrient deprivation and host phagocytes. To gain insight into cryptococcal metabolism, we optimized a protocol for the Seahorse Analyzer, which measures extracellular acidification rate (ECAR) and oxygen consumption rate (OCR) as indications of glycolytic and respiratory activities. In doing so we achieved effective immobilization of encapsulated cryptococci, established Rotenone/Antimycin A and 2-deoxyglucose as effective inhibitors of mitochondrial respiration and glycolysis, respectively, and optimized a microscopy-based method of data normalization. We applied the protocol to monitor metabolic changes in the pathogen alone and in co-culture with human blood-derived monocytes. We also compared metabolic flux in wild-type C. neoformans, its isogenic 5-PP-IP5/IP7-deficient metabolic mutant kcs1∆, the sister species of C. neoformans, Cryptococcus deuterogattii/VGII, and two other yeasts, Saccharomyces cerevisiae and Candida albicans. Our findings show that in contrast to monocytes and C. albicans, glycolysis and respiration are tightly coupled in C. neoformans and C. deuterogattii, as no compensatory increase in glycolysis occurred following inhibition of respiration. We also demonstrate that kcs1∆ has reduced metabolic activity that correlates with reduced mitochondrial function. Metabolic inflexibility in C. neoformans is therefore consistent with its obligate aerobe status and coincides with phagocyte tolerance of ingested cryptococcal cells.
Collapse
Affiliation(s)
- Sophie Lev
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Westmead, NSW 2145, Australia; (S.L.); (C.L.); (D.D.); (T.C.S.)
- Sydney Medical School—Westmead, The University of Sydney, Westmead, NSW 2145, Australia;
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW 2050, Australia
| | - Cecilia Li
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Westmead, NSW 2145, Australia; (S.L.); (C.L.); (D.D.); (T.C.S.)
- Sydney Medical School—Westmead, The University of Sydney, Westmead, NSW 2145, Australia;
| | - Desmarini Desmarini
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Westmead, NSW 2145, Australia; (S.L.); (C.L.); (D.D.); (T.C.S.)
- Sydney Medical School—Westmead, The University of Sydney, Westmead, NSW 2145, Australia;
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW 2050, Australia
| | - David Liuwantara
- Centre for Transplant and Renal Research, The Westmead Institute for Medical Research, Westmead, NSW 2145, Australia;
| | - Tania C. Sorrell
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Westmead, NSW 2145, Australia; (S.L.); (C.L.); (D.D.); (T.C.S.)
- Sydney Medical School—Westmead, The University of Sydney, Westmead, NSW 2145, Australia;
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW 2050, Australia
| | - Wayne J. Hawthorne
- Sydney Medical School—Westmead, The University of Sydney, Westmead, NSW 2145, Australia;
- Centre for Transplant and Renal Research, The Westmead Institute for Medical Research, Westmead, NSW 2145, Australia;
| | - Julianne T. Djordjevic
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Westmead, NSW 2145, Australia; (S.L.); (C.L.); (D.D.); (T.C.S.)
- Sydney Medical School—Westmead, The University of Sydney, Westmead, NSW 2145, Australia;
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW 2050, Australia
- Correspondence:
| |
Collapse
|
7
|
Mody CH, Ogbomo H, Xiang RF, Kyei SK, Feehan D, Islam A, Li SS. Microbial killing by NK cells. J Leukoc Biol 2019; 105:1285-1296. [PMID: 30821868 DOI: 10.1002/jlb.mr0718-298r] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Revised: 01/21/2019] [Accepted: 02/10/2019] [Indexed: 11/07/2022] Open
Abstract
It is now evident that NK cells kill bacteria, fungi, and parasites in addition to tumor and virus-infected cells. In addition to a number of recent publications that have identified the receptors and ligands, and mechanisms of cytotoxicity, new insights are reflected in the reports from researchers all over the world at the 17th Meeting of the Society for Natural Immunity held in San Antonio, TX, USA from May 28 through June 1, 2018. We will provide an overview of the field and discuss how the presentations at the meeting might shape our knowledge and future directions in the field.
Collapse
Affiliation(s)
- Christopher H Mody
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
- The Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
- Department of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Henry Ogbomo
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
- The Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Richard F Xiang
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
- The Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Stephen K Kyei
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
- The Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - David Feehan
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
- The Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Anowara Islam
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
- The Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Shu Shun Li
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
- The Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| |
Collapse
|
8
|
Lev S, Djordjevic JT. Why is a functional PHO pathway required by fungal pathogens to disseminate within a phosphate-rich host: A paradox explained by alkaline pH-simulated nutrient deprivation and expanded PHO pathway function. PLoS Pathog 2018; 14:e1007021. [PMID: 29928051 PMCID: PMC6013017 DOI: 10.1371/journal.ppat.1007021] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Sophie Lev
- Centre for Infectious Diseases and Microbiology, Westmead Institute for Medical Research, Westmead, Australia
- Sydney Medical School-Westmead, University of Sydney, Westmead, Australia
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, Australia
| | - Julianne Teresa Djordjevic
- Centre for Infectious Diseases and Microbiology, Westmead Institute for Medical Research, Westmead, Australia
- Sydney Medical School-Westmead, University of Sydney, Westmead, Australia
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, Australia
- * E-mail:
| |
Collapse
|
9
|
Trevijano-Contador N, de Oliveira HC, García-Rodas R, Rossi SA, Llorente I, Zaballos Á, Janbon G, Ariño J, Zaragoza Ó. Cryptococcus neoformans can form titan-like cells in vitro in response to multiple signals. PLoS Pathog 2018; 14:e1007007. [PMID: 29775477 PMCID: PMC5959073 DOI: 10.1371/journal.ppat.1007007] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 04/03/2018] [Indexed: 02/07/2023] Open
Abstract
Cryptococcus neoformans is an encapsulated pathogenic yeast that can change the size of the cells during infection. In particular, this process can occur by enlarging the size of the capsule without modifying the size of the cell body, or by increasing the diameter of the cell body, which is normally accompanied by an increase of the capsule too. This last process leads to the formation of cells of an abnormal enlarged size denominated titan cells. Previous works characterized titan cell formation during pulmonary infection but research on this topic has been hampered due to the difficulty to obtain them in vitro. In this work, we describe in vitro conditions (low nutrient, serum supplemented medium at neutral pH) that promote the transition from regular to titan-like cells. Moreover, addition of azide and static incubation of the cultures in a CO2 enriched atmosphere favored cellular enlargement. This transition occurred at low cell densities, suggesting that the process was regulated by quorum sensing molecules and it was independent of the cryptococcal serotype/species. Transition to titan-like cell was impaired by pharmacological inhibition of PKC signaling pathway. Analysis of the gene expression profile during the transition to titan-like cells showed overexpression of enzymes involved in carbohydrate metabolism, as well as proteins from the coatomer complex, and related to iron metabolism. Indeed, we observed that iron limitation also induced the formation of titan cells. Our gene expression analysis also revealed other elements involved in titan cell formation, such as calnexin, whose absence resulted in appearance of abnormal large cells even in regular rich media. In summary, our work provides a new alternative method to investigate titan cell formation devoid the bioethical problems that involve animal experimentation. Cryptococcus neoformans is a fungal pathogen that has a significant incidence in HIV+ patients in particular, in Sub-saharan Africa, Asia and South America. This yeast poses an excellent model to investigate fungal virulence because it develops many strategies to adapt to the host and evade the immune response. One of the adaptation mechanisms involves the formation of Titan Cells, which are yeast of an abnormal large size. However, research on these cells has been limited to in vivo studies (mainly in mice) because they were not reproducibly found in vitro. In this work, we describe several conditions that induce the appearance of cells that mimic titan cells, and that we denominated as titan-like cells. The main factor that induced titan-like cells was the addition of serum to nutrient limited media. This has allowed to easily performing new approaches to characterize several signaling pathways involved in their development. We found that the formation of these cells is regulated by quorum sensing molecules, and that pathways such as cAMP and PKC regulate the process of cellular enlargement. We have also performed transcriptomic analysis, which led to the identification of new genes that could be involved in the process. This work will open different research lines that will contribute to the elucidation of the role of these cells during infection and on the development of cryptococcal disease.
Collapse
Affiliation(s)
- Nuria Trevijano-Contador
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Haroldo Cesar de Oliveira
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
- Universidade Estadual Paulista (UNESP), Faculdade de Ciências Farmacêuticas, Câmpus Araraquara, Departamento de Análises Clínicas, Laboratório de Micologia Clínica, Araraquara, São Paulo, Brazil
| | - Rocío García-Rodas
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Suélen Andreia Rossi
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Irene Llorente
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Ángel Zaballos
- Genomics Unit, Core Scientific Services, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Guilhem Janbon
- Institut Pasteur, Unité Biologie des ARN des Pathogènes Fongiques, Département de Mycologie, Paris, France
| | - Joaquín Ariño
- Institut de Biotecnologia i Biomedicina and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain
| | - Óscar Zaragoza
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
- * E-mail:
| |
Collapse
|
10
|
Muranda AZ, Greeff L, Sathekge MM, Lengano T, Karusseit VOL. Cryptococcoma of a transplanted kidney in a patient presenting with recurrent urinary tract infection: a case report. BMC Nephrol 2018; 19:94. [PMID: 29688849 PMCID: PMC5914020 DOI: 10.1186/s12882-018-0891-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 04/09/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cryptococcosis is an important opportunistic infection of organ transplant recipients. It is the third most common fungal infection of transplant patients and occurs especially in kidney recipients. Cryptococcus neoformans is a ubiquitous fungus which infects humans by inhalation of spores. C. gattii has more recently been recognised as a pathogen. Infection commonly is disseminated affecting mainly the central nervous system and the lungs. Cryptococcoma, a localised form of the disease, has been described in various organs. We present a unique case of a cryptococcoma in a transplanted kidney. The lesion was not seen on ultrasound or uncontrasted computerised tomography but was detected by FDG-PET/CT. CASE PRESENTATION A 30 year old woman received a deceased donor kidney transplant in 2005. Due to chronic allograft nephropathy in 2014, cyclosporine and azathioprine immunosuppression was changed to tacrolimus and mycophenolate. After rapid deterioration of renal function in 2015 due to suspected non-adherence to immunosuppressants, steroid pulses were administered. The patient developed severe recurrent bacterial urinary tract infections and demonstrated several features of severe immunosuppression. She was treated for cytomegalovirus infection and BK virus was demonstrated in the urine. In addition, Kaposi sarcoma of the stomach was diagnosed on endoscopic biopsy. A metabolically-active lesion of the kidney transplant was imaged on FDG-PET/CT scan. Biopsy of the lesion demonstrated infection with cryptococcus. Escherichia coli with the same antibiotic sensitivity spectrum as that in the urine was cultured from the biopsy. Cryptococcus was not cultured from urine at that time or from several subsequent specimens. The lesion was not detected by conventional imaging. The patient manifested no other evidence of cryptococcosis. The lesion responded poorly to treatment with fluconazole. CONCLUSIONS This is probably the first report of a case of a cryptococcoma in a transplanted organ. FDG-PET/CT scan, which is dependent on cellular metabolism, proved useful in visualising the lesion. Clinicians should be aware of this rare presentation of cryptococcosis in organ transplant recipients.
Collapse
Affiliation(s)
- Albert Z Muranda
- Department of Nephrology, Steve Biko Academic Hospital and The University of Pretoria, Pretoria, South Africa
| | - Ludolf Greeff
- Department of Nephrology, Steve Biko Academic Hospital and The University of Pretoria, Pretoria, South Africa
| | - Mike M Sathekge
- Department of Nuclear Medicine, Steve Biko Academic Hospital and The University of Pretoria, Pretoria, South Africa
| | - Thabo Lengano
- Department of Nuclear Medicine, Steve Biko Academic Hospital and The University of Pretoria, Pretoria, South Africa
| | - Victor O L Karusseit
- Department of Surgery, Faculty of Health Sciences, Steve Biko Academic Hospital and The University of Pretoria, Private Bag X323, Arcadia, Pretoria, 0007, South Africa.
| |
Collapse
|
11
|
Uppar A, Raj ARP, Konar S, Kandregula S, Shukla D, Somanna S, Devi BI, C Y, Chandrashekar N. Intracranial Cryptococcoma-Clinicopathologic Correlation and Surgical Outcome: A Single-Institution Experience. World Neurosurg 2018; 115:e349-e359. [PMID: 29678697 DOI: 10.1016/j.wneu.2018.04.056] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 04/07/2018] [Accepted: 04/09/2018] [Indexed: 10/17/2022]
Abstract
OBJECTIVE To describe clinical characteristics of patients with intracranial cryptococcoma, clinicopathologic findings, and outcomes after surgery. MATERIALS AND METHODS Clinical data were collected from hospital case records, and pathologic confirmation was done by a neuropathologist. Clinical details, imaging features, and treatment modalities were evaluated and correlated with outcomes based on regular follow-up. RESULTS This case series included 5 cases of histology- and culture-proven intracranial cryptococcoma. Three patients (60%) were aged between the 3rd and 5th decades. Three cases were supratentorial in location, and 2 were in the posterior fossa. One patient presented with seizures. Three patients (60%) presented with fever. Three patients (60%) had papilledema, and 4 (80%) had signs of meningeal irritation. Four patients (80%) were immunocompetent. Only 1 patient was immunocompromised. All lesions were peripherally enhancing on computed tomography. Four of 5 patients underwent surgical decompression without any residue. Only 1 patient underwent stereotactic biopsy. All patients received antifungal therapy. One patient who was immunocompromised developed multiorgan failure and died after 2 months after surgery (20%). Of 5 cases, 4 (80%) had a good outcome with a mean follow-up of 5 years. CONCLUSIONS Cryptococcus gattii is a rarer species implicated in intracranial cryptococcoma that is seen along with the more common Cryptococcus neoformans. Early diagnosis and surgical decompression followed by intravenous amphotericin B therapy for at least 6 weeks and concomitant therapy with fluconazole for prolonged periods may reduce morbidity and mortality.
Collapse
Affiliation(s)
- Alok Uppar
- Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - A R Prabhu Raj
- Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bangalore, India.
| | - Subhas Konar
- Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Sandeep Kandregula
- Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Dhaval Shukla
- Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Sampath Somanna
- Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - B Indira Devi
- Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Yasha C
- Department of Neuropathology, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Nagarathna Chandrashekar
- Department of Neuro Microbiology, National Institute of Mental Health and Neurosciences, Bangalore, India
| |
Collapse
|
12
|
Differential In Vitro Cytokine Induction by the Species of Cryptococcus gattii Complex. Infect Immun 2018; 86:IAI.00958-17. [PMID: 29311248 DOI: 10.1128/iai.00958-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 01/04/2018] [Indexed: 12/13/2022] Open
Abstract
Cryptococcal species vary in capsule and cell size, thermotolerance, geographic distribution, and affected populations. Cryptococcus gattii sensu stricto and C. deuterogattii affect mainly immunocompetent hosts; however, C. bacillisporus, C. decagattii, and C. tetragattii cause infections mainly in immunocompromised hosts. This study aimed to compare the capacities of different species of the C. gattii species complex to induce cytokines and antimicrobial molecules in human peripheral blood mononuclear cells (PBMCs). Cryptococcus bacillisporus and C. deuterogattii induced the lowest levels of tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), and IL-6 among the five species of the C. gattii complex. Cryptococcus deuterogattii induced higher levels of IL-22 than those induced by C. tetragattii and the environmental species C. flavescens In addition, C. bacillisporus and C. gattii sensu stricto proliferated inside human monocyte-derived macrophages after 24 h of infection. All Cryptococcus species were able to generate reactive oxygen species (ROS) in human PBMCs, with C. bacillisporus and C. deuterogattii being more efficient than the other species. In conclusion, C. bacillisporus and C. deuterogattii induce lower levels of the proinflammatory cytokines TNF-α, IL-1β, and IL-6 and higher ROS levels than those induced by the other species. Species of the Cryptococcus gattii complex have different abilities to induce cytokine and ROS production by human PBMCs.
Collapse
|
13
|
Van Dyke MCC, Chaturvedi AK, Hardison SE, Leopold Wager CM, Castro-Lopez N, Hole CR, Wozniak KL, Wormley FL. Induction of Broad-Spectrum Protective Immunity against Disparate Cryptococcus Serotypes. Front Immunol 2017; 8:1359. [PMID: 29163469 PMCID: PMC5670106 DOI: 10.3389/fimmu.2017.01359] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 10/04/2017] [Indexed: 12/17/2022] Open
Abstract
Cryptococcosis is a fungal disease caused by multiple Cryptococcus serotypes; particularly C. neoformans (serotypes A and D) and C. gattii (serotypes B and C). To date, there is no clinically available vaccine to prevent cryptococcosis. Mice given an experimental pulmonary vaccination with a C. neoformans serotype A strain engineered to produce interferon-γ, denoted H99γ, are protected against a subsequent otherwise lethal experimental infection with C. neoformans serotype A. Thus, we determined the efficacy of immunization with C. neoformans strain H99γ to elicit broad-spectrum protection in BALB/c mice against multiple disparate Cryptococcus serotypes. We observed significantly increased survival rates and significantly decreased pulmonary fungal burden in H99γ immunized mice challenged with Cryptococcus serotypes A, B, or D compared to heat-killed H99γ (HKH99γ) immunized mice. Results indicated that prolonged protection against Cryptococcus serotypes B or D in H99γ immunized mice was CD4+ T cell dependent and associated with the induction of predominantly Th1-type cytokine responses. Interestingly, immunization with H99γ did not elicit greater protection against challenge with the Cryptococcus serotype C tested either due to low overall virulence of this strain or enhanced capacity of this strain to evade host immunity. Altogether, these studies provide “proof-of-concept” for the development of a cryptococcal vaccine that provides cross-protection against multiple disparate serotypes of Cryptococcus.
Collapse
Affiliation(s)
- Marley C Caballero Van Dyke
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States.,The South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX, United States
| | - Ashok K Chaturvedi
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States.,The South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX, United States
| | - Sarah E Hardison
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States.,The South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX, United States
| | - Chrissy M Leopold Wager
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States.,The South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX, United States
| | - Natalia Castro-Lopez
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States.,The South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX, United States
| | - Camaron R Hole
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States.,The South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX, United States
| | - Karen L Wozniak
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States.,The South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX, United States
| | - Floyd L Wormley
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States.,The South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX, United States
| |
Collapse
|
14
|
Palanco AC, Lacorte Singulani JD, Costa-Orlandi CB, Gullo FP, Strohmayer Lourencetti NM, Gomes PC, Ayusso GM, Dutra LA, Silva Bolzani VD, Regasini LO, Soares Mendes-Giannini MJ, Fusco-Almeida AM. Activity of 3'-hydroxychalcone against Cryptococcus gattii and toxicity, and efficacy in alternative animal models. Future Microbiol 2017; 12:1123-1134. [PMID: 28876122 DOI: 10.2217/fmb-2017-0062] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
AIM This work aimed to evaluate the activity of 3'-hydroxychalcone against Cryptococcus gattii in planktonic and biofilm forms and their toxicity using alternative animal models. MATERIALS & METHODS Minimum inhibitory concentration and minimum fungicide concentration were determined. Biofilm formation and the susceptibility tests were performed by the 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-5-[carbonyl(phenylamino)]-2H-tetrazolium hydroxide assay. Toxicity and efficacy were checked in Danio rerio and Galleria mellonella models. RESULTS The compound 3'-hydroxychalcone showed fungicidal activity against C. gattii in both planktonic and biofilm forms. The toxicity in zebrafish embryos revealed a low lethal concentration. In G. mellonella, the compound did not show antifungal activity and larvae toxicity. CONCLUSION Because of the activity of 3'-hydroxychalcone against C. gattii in vitro, molecular modifications should be made to improve efficacy and to reduce toxicity in vivo. [Formula: see text].
Collapse
Affiliation(s)
- Ana Cerrejón Palanco
- School of Pharmaceutical Sciences, UNESP - São Paulo State University, Araraquara, São Paulo, Brazil
| | | | | | - Fernanda Patrícia Gullo
- School of Pharmaceutical Sciences, UNESP - São Paulo State University, Araraquara, São Paulo, Brazil
| | | | - Paulo César Gomes
- School of Pharmaceutical Sciences, UNESP - São Paulo State University, Araraquara, São Paulo, Brazil
| | - Gabriela Miranda Ayusso
- Institute of Biosciences, Letters & Exact Sciences, UNESP - São José do Rio Preto, São Paulo, Brazil
| | | | | | - Luis Octávio Regasini
- Institute of Biosciences, Letters & Exact Sciences, UNESP - São José do Rio Preto, São Paulo, Brazil
| | | | - Ana Marisa Fusco-Almeida
- School of Pharmaceutical Sciences, UNESP - São Paulo State University, Araraquara, São Paulo, Brazil
| |
Collapse
|
15
|
Jandú JJ, Costa MC, Santos JRA, Andrade FM, Magalhães TF, Silva MV, Castro MCAB, Coelho LCBB, Gomes AG, Paixão TA, Santos DA, Correia MTS. Treatment with pCramoll Alone and in Combination with Fluconazole Provides Therapeutic Benefits in C. gattii Infected Mice. Front Cell Infect Microbiol 2017; 7:211. [PMID: 28596945 PMCID: PMC5442327 DOI: 10.3389/fcimb.2017.00211] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 05/09/2017] [Indexed: 01/17/2023] Open
Abstract
Cryptococcus gattii is one of the main causative agents of cryptococcosis in immunocompetent individuals. Treatment of the infection is based on the use of antimycotics, however, the toxicity of these drugs and the increase of drug-resistant strains have driven the search for more effective and less toxic therapies for cryptococcosis. pCramoll are isolectins purified from seeds of Cratylia mollis, a native forage plant from Brazil, which has become a versatile tool for biomedical application. We evaluated the effect of pCramoll alone and in combination with fluconazole for the treatment of mice infected with C. gatti. pCramoll alone or in combination with fluconazole increased the survival, reduced the morbidity and improved mice behavior i.e., neuropsychiatric state, motor behavior, autonomic function, muscle tone and strength and reflex/sensory function. These results were associated with (i) decreased pulmonary and cerebral fungal burden and (ii) increased inflammatory infiltrate and modulatory of IFNγ, IL-6, IL-10, and IL-17A cytokines in mice treated with pCramoll. Indeed, bone marrow-derived macrophages pulsed with pCramoll had increased ability to engulf C. gattii, with an enhanced production of reactive oxygen species and decrease of intracellular fungal proliferation. These findings point toward the use of pCramoll in combination with fluconazole as a viable, alternative therapy for cryptococcosis management.
Collapse
Affiliation(s)
- Jannyson J Jandú
- Departamento de Bioquímica, Universidade Federal de PernambucoRecife, Brazil
| | - Marliete C Costa
- Departamento de Microbiologia, Universidade Federal de Minas GeraisBelo Horizonte, Brazil
| | | | - Fernanda M Andrade
- Departamento de Bioquímica, Universidade Federal de PernambucoRecife, Brazil
| | - Thais F Magalhães
- Departamento de Microbiologia, Universidade Federal de Minas GeraisBelo Horizonte, Brazil
| | - Márcia V Silva
- Departamento de Bioquímica, Universidade Federal de PernambucoRecife, Brazil
| | - Maria C A B Castro
- Núcleo de Enfermagem, Universidade Federal de PernambucoVitória de Santo Antão, Brazil.,Laboratório de Imunogenética, Centro de Pesquisas Aggeu MagalhãesRecife, Brazil
| | - Luanna C B B Coelho
- Departamento de Bioquímica, Universidade Federal de PernambucoRecife, Brazil
| | - Aline G Gomes
- Departamento de Patologia Geral, Instituto Universidade Federal de Minas GeraisBelo Horizonte, Brazil
| | - Tatiane A Paixão
- Departamento de Patologia Geral, Instituto Universidade Federal de Minas GeraisBelo Horizonte, Brazil
| | - Daniel A Santos
- Departamento de Microbiologia, Universidade Federal de Minas GeraisBelo Horizonte, Brazil
| | - Maria T S Correia
- Departamento de Bioquímica, Universidade Federal de PernambucoRecife, Brazil
| |
Collapse
|
16
|
Pho4 Is Essential for Dissemination of Cryptococcus neoformans to the Host Brain by Promoting Phosphate Uptake and Growth at Alkaline pH. mSphere 2017; 2:mSphere00381-16. [PMID: 28144629 PMCID: PMC5266496 DOI: 10.1128/msphere.00381-16] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 12/30/2016] [Indexed: 12/30/2022] Open
Abstract
Phosphate acquisition by fungi is regulated by the phosphate-sensing and acquisition (PHO) signaling pathway. Cryptococcus neoformans disseminates from the lung to the brain and is the commonest cause of fungal meningitis worldwide. To investigate the contribution of PHO signaling to cryptococcal dissemination, we characterized a transcription factor knockout strain (hlh3Δ/pho4Δ) defective in phosphate acquisition. Despite little similarity with other fungal Pho4 proteins, Hlh3/Pho4 functioned like a typical phosphate-responsive transcription factor in phosphate-deprived cryptococci, accumulating in nuclei and triggering expression of genes involved in phosphate acquisition. The pho4Δ mutant strain was susceptible to a number of stresses, the effect of which, except for alkaline pH, was alleviated by phosphate supplementation. Even in the presence of phosphate, the PHO pathway was activated in wild-type cryptococci at or above physiological pH, and under these conditions, the pho4Δ mutant had a growth defect and compromised phosphate uptake. The pho4Δ mutant was hypovirulent in a mouse inhalation model, where dissemination to the brain was reduced dramatically, and markedly hypovirulent in an intravenous dissemination model. The pho4Δ mutant was not detected in blood, nor did it proliferate significantly when cultured with peripheral blood monocytes. In conclusion, dissemination of infection and the pathogenesis of meningitis are dependent on cryptococcal phosphate uptake and stress tolerance at alkaline pH, both of which are Pho4 dependent. IMPORTANCE Cryptococcal meningitis is fatal without treatment and responsible for more than 500,000 deaths annually. To be a successful pathogen, C. neoformans must obtain an adequate supply of essential nutrients, including phosphate, from various host niches. Phosphate acquisition in fungi is regulated by the PHO signaling cascade, which is activated when intracellular phosphate decreases below a critical level. Induction of phosphate acquisition genes leads to the uptake of free phosphate via transporters. By blocking the PHO pathway using a Pho4 transcription factor mutant (pho4Δ mutant), we demonstrate the importance of the pathway for cryptococcal dissemination and the establishment of brain infection in murine models. Specifically, we show that reduced dissemination of the pho4Δ mutant to the brain is due to an alkaline pH tolerance defect, as alkaline pH mimics the conditions of phosphate deprivation. The end result is inhibited proliferation in host tissues, particularly in blood.
Collapse
|
17
|
Leopold Wager CM, Hole CR, Wozniak KL, Wormley FL. Cryptococcus and Phagocytes: Complex Interactions that Influence Disease Outcome. Front Microbiol 2016; 7:105. [PMID: 26903984 PMCID: PMC4746234 DOI: 10.3389/fmicb.2016.00105] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 01/19/2016] [Indexed: 12/18/2022] Open
Abstract
Cryptococcus neoformans and C. gattii are fungal pathogens that cause life-threatening disease. These fungi commonly enter their host via inhalation into the lungs where they encounter resident phagocytes, including macrophages and dendritic cells, whose response has a pronounced impact on the outcome of disease. Cryptococcus has complex interactions with the resident and infiltrating innate immune cells that, ideally, result in destruction of the yeast. These phagocytic cells have pattern recognition receptors that allow recognition of specific cryptococcal cell wall and capsule components. However, Cryptococcus possesses several virulence factors including a polysaccharide capsule, melanin production and secretion of various enzymes that aid in evasion of the immune system or enhance its ability to thrive within the phagocyte. This review focuses on the intricate interactions between the cryptococci and innate phagocytic cells including discussion of manipulation and evasion strategies used by Cryptococcus, anti-cryptococcal responses by the phagocytes and approaches for targeting phagocytes for the development of novel immunotherapeutics.
Collapse
Affiliation(s)
- Chrissy M Leopold Wager
- Department of Biology, The University of Texas at San AntonioSan Antonio, TX, USA; The South Texas Center for Emerging Infectious Diseases, The University of Texas at San AntonioSan Antonio, TX, USA
| | - Camaron R Hole
- Department of Biology, The University of Texas at San AntonioSan Antonio, TX, USA; The South Texas Center for Emerging Infectious Diseases, The University of Texas at San AntonioSan Antonio, TX, USA
| | - Karen L Wozniak
- Department of Biology, The University of Texas at San AntonioSan Antonio, TX, USA; The South Texas Center for Emerging Infectious Diseases, The University of Texas at San AntonioSan Antonio, TX, USA
| | - Floyd L Wormley
- Department of Biology, The University of Texas at San AntonioSan Antonio, TX, USA; The South Texas Center for Emerging Infectious Diseases, The University of Texas at San AntonioSan Antonio, TX, USA
| |
Collapse
|
18
|
Rella A, Mor V, Farnoud AM, Singh A, Shamseddine AA, Ivanova E, Carpino N, Montagna MT, Luberto C, Del Poeta M. Role of Sterylglucosidase 1 (Sgl1) on the pathogenicity of Cryptococcus neoformans: potential applications for vaccine development. Front Microbiol 2015; 6:836. [PMID: 26322039 PMCID: PMC4531891 DOI: 10.3389/fmicb.2015.00836] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2015] [Accepted: 07/29/2015] [Indexed: 01/01/2023] Open
Abstract
Cryptococcosis caused by Cryptococcus neoformans and Cryptococcus gattii affects a large population and is a cause of significant morbidity and mortality. Despite its public health burden, there are currently no vaccines against cryptococcosis and new strategies against such infections are needed. In this study, we demonstrate that C. neoformans has the biochemical ability to metabolize sterylglucosides (SGs), a class of immunomodulatory glycolipids. Genetic manipulations that eliminate cryptococccal sterylglucosidase lead to the accumulation of SGs and generate a mutant strain (Δsgl1) that is non-pathogenic in the mouse models of cryptococcosis. Interestingly, this mutant strain acts as a vaccine strain and protects mice against cryptococcosis following infection with C. neoformans or C. gattii. The immunity induced by the Δsgl1 strain is not CD4+ T-cells dependent. Immunocompromised mice, which lack CD4+ T-cells, are able to control the infection by Δsgl1 and acquire immunity against the challenge by wild-type C. neoformans following vaccination with the Δsgl1 strain. These findings are particularly important in the context of HIV/AIDS immune deficiency and suggest that the Δsgl1 strain might provide a potential vaccination strategy against cryptococcosis.
Collapse
Affiliation(s)
- Antonella Rella
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook NY, USA
| | - Visesato Mor
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook NY, USA
| | - Amir M Farnoud
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook NY, USA
| | - Ashutosh Singh
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook NY, USA
| | | | - Elitza Ivanova
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook NY, USA
| | - Nicholas Carpino
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook NY, USA
| | - Maria T Montagna
- Department of Biomedical Science and Human Oncology, Hygiene Section, University of Bari Bari, Italy
| | - Chiara Luberto
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook NY, USA
| | - Maurizio Del Poeta
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook NY, USA
| |
Collapse
|
19
|
Abstract
Understanding of the taxonomy and phylogeny of Cryptococcus gattii has been advanced by modern molecular techniques. C. gattii probably diverged from Cryptococcus neoformans between 16 million and 160 million years ago, depending on the dating methods applied, and maintains diversity by recombining in nature. South America is the likely source of the virulent C. gattii VGII molecular types that have emerged in North America. C. gattii shares major virulence determinants with C. neoformans, although genomic and transcriptomic studies revealed that despite similar genomes, the VGIIa and VGIIb subtypes employ very different transcriptional circuits and manifest differences in virulence phenotypes. Preliminary evidence suggests that C. gattii VGII causes severe lung disease and death without dissemination, whereas C. neoformans disseminates readily to the central nervous system (CNS) and causes death from meningoencephalitis. Overall, currently available data indicate that the C. gattii VGI, VGII, and VGIII molecular types more commonly affect nonimmunocompromised hosts, in contrast to VGIV. New, rapid, cheap diagnostic tests and imaging modalities are assisting early diagnosis and enabling better outcomes of cerebral cryptococcosis. Complications of CNS infection include increased intracranial pressure, severe neurological sequelae, and development of immune reconstitution syndrome, although the mortality rate is low. C. gattii VGII isolates may exhibit higher fluconazole MICs than other genotypes. Optimal therapeutic regimens are yet to be determined; in most cases, initial therapy with amphotericin B and 5-flucytosine is recommended.
Collapse
|
20
|
Mukhopadhyay SL, Kumar M, Chickabasaviah YT, Bahubali VKH, Raj PA, Bharath RD, Siddaiah N. Cerebellar cryptococcoma due to Cryptococcus gattii VGI; a rare and first report from India. JMM Case Rep 2015. [DOI: 10.1099/jmmcr.0.000052] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
| | - Mukesh Kumar
- National institute of Mental Health and Neuro Sciences, Hosur Road, Bangalore 560029, Karnataka, India
| | - Yasha T. Chickabasaviah
- National institute of Mental Health and Neuro Sciences, Hosur Road, Bangalore 560029, Karnataka, India
| | - Veena Kumari H. Bahubali
- National institute of Mental Health and Neuro Sciences, Hosur Road, Bangalore 560029, Karnataka, India
| | - Prabhu A.R. Raj
- National institute of Mental Health and Neuro Sciences, Hosur Road, Bangalore 560029, Karnataka, India
| | - Rose Dawn Bharath
- National institute of Mental Health and Neuro Sciences, Hosur Road, Bangalore 560029, Karnataka, India
| | - Nagarathna Siddaiah
- National institute of Mental Health and Neuro Sciences, Hosur Road, Bangalore 560029, Karnataka, India
| |
Collapse
|
21
|
Taylor T, Bose I, Luckie T, Smith K. Biolistic transformation of a fluorescent tagged gene into the opportunistic fungal pathogen Cryptococcus neoformans. J Vis Exp 2015:52666. [PMID: 25867491 PMCID: PMC4401375 DOI: 10.3791/52666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The basidiomycete Cryptococcus neoformans, an invasive opportunistic pathogen of the central nervous system, is the most frequent cause of fungal meningitis worldwide resulting in more than 625,000 deaths per year worldwide. Although electroporation has been developed for the transformation of plasmids in Cryptococcus, only biolistic delivery provides an effective means to transform linear DNA that can be integrated into the genome by homologous recombination. Acetate has been shown to be a major fermentation product during cryptococcal infection, but the significance of this is not yet known. A bacterial pathway composed of the enzymes xylulose-5-phosphate/fructose-6-phosphate phosphoketolase (Xfp) and acetate kinase (Ack) is one of three potential pathways for acetate production in C. neoformans. Here, we demonstrate the biolistic transformation of a construct, which has the gene encoding Ack fused to the fluorescent tag mCherry, into C. neoformans. We then confirm integration of the ACK-mCherry fusion into the ACK locus.
Collapse
Affiliation(s)
- Tonya Taylor
- Department of Genetics and Biochemistry, Eukaryotic Pathogens Innovation Center (EPIC), Clemson University
| | - Indrani Bose
- Department of Biology, Western Carolina University
| | - Taylor Luckie
- Department of Genetics and Biochemistry, Eukaryotic Pathogens Innovation Center (EPIC), Clemson University
| | - Kerry Smith
- Department of Genetics and Biochemistry, Eukaryotic Pathogens Innovation Center (EPIC), Clemson University;
| |
Collapse
|
22
|
Azevedo MID, Ferreiro L, Da Silva AS, Tonin AA, Ruchel JB, Rezer JF, França RT, Zimmermann CE, Leal DB, Duarte MM, Lopes ST, Flores MM, Fighera R, Santurio JM. E-NTPDase and E-ADA activities in rats experimental infected by Cryptococcus neoformans. Vet Microbiol 2014; 174:206-13. [DOI: 10.1016/j.vetmic.2014.09.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 07/15/2014] [Accepted: 09/09/2014] [Indexed: 12/20/2022]
|
23
|
Identification of Aph1, a phosphate-regulated, secreted, and vacuolar acid phosphatase in Cryptococcus neoformans. mBio 2014; 5:e01649-14. [PMID: 25227465 PMCID: PMC4172073 DOI: 10.1128/mbio.01649-14] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cryptococcus neoformans strains isolated from patients with AIDS secrete acid phosphatase, but the identity and role of the enzyme(s) responsible have not been elucidated. By combining a one-dimensional electrophoresis step with mass spectrometry, a canonically secreted acid phosphatase, CNAG_02944 (Aph1), was identified in the secretome of the highly virulent serotype A strain H99. We created an APH1 deletion mutant (Δaph1) and showed that Δaph1-infected Galleria mellonella and mice survived longer than those infected with the wild type (WT), demonstrating that Aph1 contributes to cryptococcal virulence. Phosphate starvation induced APH1 expression and secretion of catalytically active acid phosphatase in the WT, but not in the Δaph1 mutant, indicating that Aph1 is the major extracellular acid phosphatase in C. neoformans and that it is phosphate repressible. DsRed-tagged Aph1 was transported to the fungal cell periphery and vacuoles via endosome-like structures and was enriched in bud necks. A similar pattern of Aph1 localization was observed in cryptococci cocultured with THP-1 monocytes, suggesting that Aph1 is produced during host infection. In contrast to Aph1, but consistent with our previous biochemical data, green fluorescent protein (GFP)-tagged phospholipase B1 (Plb1) was predominantly localized at the cell periphery, with no evidence of endosome-mediated export. Despite use of different intracellular transport routes by Plb1 and Aph1, secretion of both proteins was compromised in a Δsec14-1 mutant. Secretions from the WT, but not from Δaph1, hydrolyzed a range of physiological substrates, including phosphotyrosine, glucose-1-phosphate, β-glycerol phosphate, AMP, and mannose-6-phosphate, suggesting that the role of Aph1 is to recycle phosphate from macromolecules in cryptococcal vacuoles and to scavenge phosphate from the extracellular environment. Infections with the AIDS-related fungal pathogen Cryptococcus neoformans cause more than 600,000 deaths per year worldwide. Strains of Cryptococcus neoformans isolated from patients with AIDS secrete acid phosphatase; however, the identity and role of the enzyme(s) are unknown. We have analyzed the secretome of the highly virulent serotype A strain H99 and identified Aph1, a canonically secreted acid phosphatase. By creating an APH1 deletion mutant and an Aph1-DsRed-expressing strain, we demonstrate that Aph1 is the major extracellular and vacuolar acid phosphatase in C. neoformans and that it is phosphate repressible. Furthermore, we show that Aph1 is produced in cryptococci during coculture with THP-1 monocytes and contributes to fungal virulence in Galleria mellonella and mouse models of cryptococcosis. Our findings suggest that Aph1 is secreted to the environment to scavenge phosphate from a wide range of physiological substrates and is targeted to vacuoles to recycle phosphate from the expendable macromolecules.
Collapse
|
24
|
Vaccine-mediated immune responses to experimental pulmonary Cryptococcus gattii infection in mice. PLoS One 2014; 9:e104316. [PMID: 25119981 PMCID: PMC4132117 DOI: 10.1371/journal.pone.0104316] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Accepted: 07/07/2014] [Indexed: 11/25/2022] Open
Abstract
Cryptococcus gattii is a fungal pathogen that can cause life-threatening respiratory and disseminated infections in immune-competent and immune-suppressed individuals. Currently, there are no standardized vaccines against cryptococcosis in humans, underlying an urgent need for effective therapies and/or vaccines. In this study, we evaluated the efficacy of intranasal immunization with C. gattii cell wall associated (CW) and/or cytoplasmic (CP) protein preparations to induce protection against experimental pulmonary C. gattii infection in mice. BALB/c mice immunized with C. gattii CW and/or CP protein preparations exhibited a significant reduction in pulmonary fungal burden and prolonged survival following pulmonary challenge with C. gattii. Protection was associated with significantly increased pro-inflammatory and Th1-type cytokine recall responses, in vitro and increased C. gattii-specific antibody production in immunized mice challenged with C. gattii. A number of immunodominant proteins were identified following immunoblot analysis of C. gattii CW and CP protein preparations using sera from immunized mice. Immunization with a combined CW and CP protein preparation resulted in an early increase in pulmonary T cell infiltrates following challenge with C. gattii. Overall, our studies show that C. gattii CW and CP protein preparations contain antigens that may be included in a subunit vaccine to induce prolonged protection against pulmonary C. gattii infection.
Collapse
|
25
|
Feretzaki M, Hardison SE, Wormley FL, Heitman J. Cryptococcus neoformans hyperfilamentous strain is hypervirulent in a murine model of cryptococcal meningoencephalitis. PLoS One 2014; 9:e104432. [PMID: 25093333 PMCID: PMC4122496 DOI: 10.1371/journal.pone.0104432] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 07/11/2014] [Indexed: 01/08/2023] Open
Abstract
Cryptococcus neoformans is a human fungal pathogen that causes lethal infections of the lung and central nervous system in immunocompromised individuals. C. neoformans has a defined bipolar sexual life cycle with a and α mating types. During the sexual cycle, which can occur between cells of opposite mating types (bisexual reproduction) or cells of one mating type (unisexual reproduction), a dimorphic transition from yeast to hyphal growth occurs. Hyphal development and meiosis generate abundant spores that, following inhalation, penetrate deep into the lung to enter the alveoli, germinate, and establish a pulmonary infection growing as budding yeast cells. Unisexual reproduction has been directly observed only in the Cryptococcus var. neoformans (serotype D) lineage under laboratory conditions. However, hyphal development has been previously associated with reduced virulence and the serotype D lineage exhibits limited pathogenicity in the murine model. In this study we show that the serotype D hyperfilamentous strain XL280α is hypervirulent in an animal model. It can grow inside the lung of the host, establish a pulmonary infection, and then disseminate to the brain to cause cryptococcal meningoencephalitis. Surprisingly, this hyperfilamentous strain triggers an immune response polarized towards Th2-type immunity, which is usually observed in the highly virulent sibling species C. gattii, responsible for the Pacific Northwest outbreak. These studies provide a technological advance that will facilitate analysis of virulence genes and attributes in C. neoformans var. neoformans, and reveal the virulence potential of serotype D as broader and more dynamic than previously appreciated.
Collapse
Affiliation(s)
- Marianna Feretzaki
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Sarah E. Hardison
- Department of Biology, The University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - Floyd L. Wormley
- Department of Biology, The University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
- * E-mail:
| |
Collapse
|
26
|
Cryptococcus gattii infection dampens Th1 and Th17 responses by attenuating dendritic cell function and pulmonary chemokine expression in the immunocompetent hosts. Infect Immun 2014; 82:3880-90. [PMID: 24980974 DOI: 10.1128/iai.01773-14] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Cryptococcal infections are primarily caused by two related fungal species: Cryptococcus neoformans and Cryptococcus gattii. It is well known that C. neoformans generally affects immunocompromised hosts; however, C. gattii infection can cause diseases in not only immunocompromised hosts but also immunocompetent individuals. While recent studies suggest that C. gattii infection could dampen pulmonary neutrophil recruitment and inflammatory cytokine production in immunocompetent hosts, the impact of C. gattii infection on the development of their adaptive T helper cell immune response has not been addressed. Here, we report that C. neoformans infection with highly virulent and less virulent strains preferentially induced pulmonary Th1 and Th17 immune responses in the host, respectively. However, fewer pulmonary Th1 and Th17 cells could be detected in mice infected with C. gattii strains. Notably, dendritic cells (DC) in mice infected with C. gattii expressed much lower levels of surface MHC-II and Il12 or Il23 transcripts and failed to induce effective Th1 and Th17 differentiation in vitro. Furthermore, the expression levels of Ip10 and Cxcl9 transcripts, encoding Th1-attracting chemokines, were significantly reduced in the lungs of mice infected with the highly virulent C. gattii strain. Thus, our data suggest that C. gattii infection dampens the DC-mediated effective Th1/Th17 immune responses and downregulates the pulmonary chemokine expression, thus resulting in the inability to mount protective immunity in immunocompetent hosts.
Collapse
|
27
|
Glenn K, Ingram-Smith C, Smith KS. Biochemical and kinetic characterization of xylulose 5-phosphate/fructose 6-phosphate phosphoketolase 2 (Xfp2) from Cryptococcus neoformans. EUKARYOTIC CELL 2014; 13:657-63. [PMID: 24659577 PMCID: PMC4060483 DOI: 10.1128/ec.00055-14] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 03/13/2014] [Indexed: 11/20/2022]
Abstract
Xylulose 5-phosphate/fructose 6-phosphate phosphoketolase (Xfp), previously thought to be present only in bacteria but recently found in fungi, catalyzes the formation of acetyl phosphate from xylulose 5-phosphate or fructose 6-phosphate. Here, we describe the first biochemical and kinetic characterization of a eukaryotic Xfp, from the opportunistic fungal pathogen Cryptococcus neoformans, which has two XFP genes (designated XFP1 and XFP2). Our kinetic characterization of C. neoformans Xfp2 indicated the existence of both substrate cooperativity for all three substrates and allosteric regulation through the binding of effector molecules at sites separate from the active site. Prior to this study, Xfp enzymes from two bacterial genera had been characterized and were determined to follow Michaelis-Menten kinetics. C. neoformans Xfp2 is inhibited by ATP, phosphoenolpyruvate (PEP), and oxaloacetic acid (OAA) and activated by AMP. ATP is the strongest inhibitor, with a half-maximal inhibitory concentration (IC50) of 0.6 mM. PEP and OAA were found to share the same or have overlapping allosteric binding sites, while ATP binds at a separate site. AMP acts as a very potent activator; as little as 20 μM AMP is capable of increasing Xfp2 activity by 24.8% ± 1.0% (mean ± standard error of the mean), while 50 μM prevented inhibition caused by 0.6 mM ATP. AMP and PEP/OAA operated independently, with AMP activating Xfp2 and PEP/OAA inhibiting the activated enzyme. This study provides valuable insight into the metabolic role of Xfp within fungi, specifically the fungal pathogen Cryptococcus neoformans, and suggests that at least some Xfps display substrate cooperative binding and allosteric regulation.
Collapse
Affiliation(s)
- Katie Glenn
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, South Carolina, USA
| | | | | |
Collapse
|
28
|
Springer DJ, Saini D, Byrnes EJ, Heitman J, Frothingham R. Development of an aerosol model of Cryptococcus reveals humidity as an important factor affecting the viability of Cryptococcus during aerosolization. PLoS One 2013; 8:e69804. [PMID: 23894542 PMCID: PMC3720958 DOI: 10.1371/journal.pone.0069804] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Accepted: 06/12/2013] [Indexed: 12/14/2022] Open
Abstract
Cryptococcus is an emerging global health threat that is annually responsible for over 1,000,000 infections and one third of all AIDS patient deaths. There is an ongoing outbreak of cryptococcosis in the western United States and Canada. Cryptococcosis is a disease resulting from the inhalation of the infectious propagules from the environment. The current and most frequently used animal infection models initiate infection via liquid suspension through intranasal instillation or intravenous injection. These models do not replicate the typically dry nature of aerosol exposure and may hinder our ability to decipher the initial events that lead to clearance or the establishment of infection. We have established a standardized aerosol model of murine infection for the human fungal pathogen Cryptococcus. Aerosolized cells were generated utilizing a Collison nebulizer in a whole-body Madison Chamber at different humidity conditions. The aerosols inside the chamber were sampled using a BioSampler to determine viable aerosol concentration and spray factor (ratio of viable aerosol concentration to total inoculum concentration). We have effectively delivered yeast and yeast-spore mixtures to the lungs of mice and observed the establishment of disease. We observed that growth conditions prior to exposure and humidity within the Madison Chamber during exposure can alter Cryptococcus survival and dose retained in mice.
Collapse
Affiliation(s)
- Deborah J Springer
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA.
| | | | | | | | | |
Collapse
|
29
|
Islam A, Li SS, Oykhman P, Timm-McCann M, Huston SM, Stack D, Xiang RF, Kelly MM, Mody CH. An acidic microenvironment increases NK cell killing of Cryptococcus neoformans and Cryptococcus gattii by enhancing perforin degranulation. PLoS Pathog 2013; 9:e1003439. [PMID: 23853583 PMCID: PMC3708852 DOI: 10.1371/journal.ppat.1003439] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 05/06/2013] [Indexed: 12/14/2022] Open
Abstract
Cryptococcus gattii and Cryptococcus neoformans are encapsulated yeasts that can produce a solid tumor-like mass or cryptococcoma. Analogous to malignant tumors, the microenvironment deep within a cryptococcoma is acidic, which presents unique challenges to host defense. Analogous to malignant cells, NK cells kill Cryptococcus. Thus, as in tumor defense, NK cells must kill yeast cells across a gradient from physiologic pH to less than 6 in the center of the cryptococcoma. As acidic pH inhibits anti-tumor activities of NK cells, we sought to determine if there was a similar reduction in the anticryptococcal activity of NK cells. Surprisingly, we found that both primary human NK cells and the human NK cell line, YT, have preserved or even enhanced killing of Cryptococcus in acidic, compared to physiological, pH. Studies to explore the mechanism of enhanced killing revealed that acidic pH does not increase the effector to target ratio, binding of cytolytic cells to Cryptococcus, or the active perforin content in effector cells. By contrast, perforin degranulation was greater at acidic pH, and increased degranulation was preceded by enhanced ERK1/2 phosphorylation, which is essential for killing. Moreover, using a replication defective ras1 knockout strain of Cryptococcus increased degranulation occurred during more rapid replication of the organisms. Finally, NK cells were found intimately associated with C. gattii within the cryptococcoma of a fatal infection. These results suggest that NK cells have amplified signaling, degranulation, and greater killing at low pH and when the organisms are replicating quickly, which would help maintain microbicidal host defense despite an acidic microenvironment. Immune responses that protect from infection must occur in a variety of unique and potentially hostile environments. Within these environments, acidosis causes profound affects on protective responses. Low pH can occur in focal tumor-like infections, such as in a cryptococcoma produced by the fungal pathogen Cryptococcus. Similarly, low pH occurs in focal malignant tumors. It follows that Cryptococcus and malignant cells can both be killed by NK cells, which provide an important mechanism of host defense. Thus, we asked whether low pH, which impairs tumor killing, might also affect NK cell killing of Cryptococcus. Surprisingly, despite impaired tumor killing, NK cells possess enhanced killing of Cryptococcus at low pH. The mechanism involved a gain in intracellular signal transduction that led to enhanced perforin degranulation. This led us to examine NK cells in persistent cryptococcoma of a fatal brain infection and lung. We found that NK cells associate with Cryptococcus within the cryptococcoma, but perforin is reduced. These studies suggest NK cell cytotoxicity need not be impaired at low pH, and that enhanced signal transduction and degranulation at low pH might be used to enhance host defense.
Collapse
Affiliation(s)
- Anowara Islam
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Shu Shun Li
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Paul Oykhman
- Department of Medical Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Martina Timm-McCann
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Shaunna M. Huston
- Department of Medical Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Danuta Stack
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Richard F. Xiang
- Department of Medical Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Margaret M. Kelly
- Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Christopher H. Mody
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
- Department of Internal Medicine, University of Calgary, Calgary, Alberta, Canada
- * E-mail:
| |
Collapse
|
30
|
Hole CR, Wormley FL. Vaccine and immunotherapeutic approaches for the prevention of cryptococcosis: lessons learned from animal models. Front Microbiol 2012; 3:291. [PMID: 22973262 PMCID: PMC3428735 DOI: 10.3389/fmicb.2012.00291] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Accepted: 07/24/2012] [Indexed: 12/19/2022] Open
Abstract
Cryptococcus neoformans and C. gattii, the predominant etiological agents of cryptococcosis, can cause life-threatening infections of the central nervous system in immunocompromised and immunocompetent individuals. Cryptococcal meningoencephalitis is the most common disseminated fungal infection in AIDS patients, and C. neoformans remains the third most common invasive fungal infection among organ transplant recipients. Current anti-fungal drug therapies are oftentimes rendered ineffective due to drug toxicity, the emergence of drug resistant organisms, and/or the inability of the host's immune defenses to assist in eradication of the yeast. Therefore, there remains an urgent need for the development of immune-based therapies and/or vaccines to combat cryptococcosis. Studies in animal models have demonstrated the efficacy of various vaccination strategies and immune therapies to induce protection against cryptococcosis. This review will summarize the lessons learned from animal models supporting the feasibility of developing immunotherapeutics and vaccines to prevent cryptococcosis.
Collapse
Affiliation(s)
- Camaron R Hole
- Department of Biology, The University of Texas at San Antonio San Antonio, TX, USA
| | | |
Collapse
|
31
|
Abstract
Cryptococcosis is the leading invasive fungal infection in the world today. Over the past century, the causative agents, Cryptococcus neoformans and Cryptococcus gattii, have risen from the status of medical curiosities to common but life-threatening central nervous system pathogens. In an elegant experimental pathobiology study of these two organisms carried out by Ngamskulrungroj et al., there are three matters that merit further discussion. First is the question of whether there is a variable specific pathobiology for each yeast strain. Does it make biological and clinical sense to designate C. neoformans and C. gattii as two separate species? Second is the matter of how the organisms differ pathologically at the site of infection. Finally, there is the possibility that the human immune system responds differently to each species. Although no single study can provide definitive mechanistic answers to the important questions, this experimental pathology study and its discussion clearly frame the issues to be dissected.
Collapse
|
32
|
A decade of experience: Cryptococcus gattii in British Columbia. Mycopathologia 2011; 173:311-9. [PMID: 21960040 DOI: 10.1007/s11046-011-9475-x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Accepted: 09/02/2011] [Indexed: 12/31/2022]
Abstract
It has been over a decade since Cryptococcus gattii was first recognized as the causative organism of an outbreak of cryptococcosis on Vancouver Island, British Columbia. A number of novel observations have been associated with the study of this emergent pathogen. A novel genotype of C. gattii, VGIIa was described as the major genotype associated with clinical disease. Minor genotypes, VGIIb and VGI, are also responsible for disease in British Columbians, in both human and animal populations. The clinical major genotype VGIIa and minor genotype VGIIb are identical to C. gattii isolated from the environment of Vancouver Island. There is more heterogeneity in VGI, and a clear association with the environment is not apparent. Between 1999 and 2010, there have been 281 cases of C. gattii cryptococcosis. Risk factors for infection are reported to be age greater than 50 years, history of smoking, corticosteroid use, HIV infection, and history of cancer or chronic lung disease. The major C. gattii genotype VGIIa is as virulent in mice as the model Cryptococcus, H99 C. neoformans, although the outbreak strain produces a less protective inflammatory response in C57BL/6 mice. The minor genotype VGIIb is significantly less virulent in mouse models. Cryptococcus gattii is found associated with native trees and soil on Vancouver Island. Transiently positive isolations have been made from air and water. An ecological niche for this organism is associated within a limited biogeoclimatic zone characterized by daily average winter temperatures above freezing.
Collapse
|
33
|
Abstract
Infections caused by the emerging pathogen Cryptococcus gattii are increasing in frequency in North America. During the past decade, interest in the pathogen has continued to grow, not only in North America but also in other areas of the world where infections have recently been documented. This review synthesizes existing data and raises issues that remain to be addressed.
Collapse
Affiliation(s)
- Julie Harris
- Mycotic Diseases Branch, Centers for Disease Control and Prevention, 1600 Clifton Rd NE, MS C-09, Atlanta, GA 30309 USA.
| | | | | |
Collapse
|
34
|
Chaturvedi V, Chaturvedi S. Cryptococcus gattii: a resurgent fungal pathogen. Trends Microbiol 2011; 19:564-71. [PMID: 21880492 DOI: 10.1016/j.tim.2011.07.010] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Revised: 07/19/2011] [Accepted: 07/29/2011] [Indexed: 01/20/2023]
Abstract
Cryptococcus gattii and Cryptococcus neoformans are causal agents of cryptococcosis, which manifests as pneumonia and meningitis. C. gattii has recently received widespread attention owing to outbreaks in British Columbia, Canada and the US Pacific Northwest. The biology of this tree-dwelling yeast is relatively unexplored, and there are few clues about how it causes infections in humans and animals. In this review, we summarize recent discoveries about C. gattii genetics and its ecological niche and highlight areas ripe for future exploration. Increased focus on epidemiology, ecological modeling and host-pathogen interactions is expected to yield a better understanding of this enigmatic yeast, and ultimately lead to better measures for its control.
Collapse
Affiliation(s)
- Vishnu Chaturvedi
- Mycology Laboratory, Wadsworth Center, New York State Department of Health, Albany, NY 12208, USA.
| | | |
Collapse
|
35
|
Chayakulkeeree M, Johnston SA, Oei JB, Lev S, Williamson PR, Wilson CF, Zuo X, Leal AL, Vainstein MH, Meyer W, Sorrell TC, May RC, Djordjevic JT. SEC14 is a specific requirement for secretion of phospholipase B1 and pathogenicity of Cryptococcus neoformans. Mol Microbiol 2011; 80:1088-101. [PMID: 21453402 DOI: 10.1111/j.1365-2958.2011.07632.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Secreted phospholipase B1 (CnPlb1) is essential for dissemination of Cryptococcus neoformans to the central nervous system (CNS) yet essential components of its secretion machinery remain to be elucidated. Using gene deletion analysis we demonstrate that CnPlb1 secretion is dependent on the CnSEC14 product, CnSec14-1p. CnSec14-1p is a homologue of the phosphatidylinositol transfer protein ScSec14p, which is essential for secretion and viability in Saccharomyces cerevisiae. In contrast to CnPlb1, neither laccase 1-induced melanization within the cell wall nor capsule induction were negatively impacted in CnSEC14-1 deletion mutants (CnΔsec14-1 and CnΔsec14-1CnΔsfh5). Similar to the CnPLB1 deletion mutant (CnΔplb1), CnΔsec14-1 was hypovirulent in mice and did not disseminate to the CNS by day 14 post infection. Furthermore, macrophage expulsion of live CnΔsec14-1 and CnΔplb1 (vomocytosis) was reduced. Individual deletion of CnSEC14-2, a closely related CnSEC14-1 homologue, and CnSFH5, a distantly related SEC fourteen like homologue, did not abrogate CnPlb1 secretion or virulence. However, reconstitution of CnΔsec14-1 with CnSEC14-1 or CnSEC14-2 restored both phenotypes, consistent with functional genetic redundancy. We conclude that CnPlb1 secretion is SEC14-dependent and that C. neoformans preferentially exports virulence determinants to the cell periphery via distinct pathways. We also demonstrate that CnPlb1 secretion is essential for vomocytosis.
Collapse
Affiliation(s)
- Methee Chayakulkeeree
- Centre for Infectious Diseases and Microbiology, Sydney Medical School-Western, and Westmead Millennium Institute, University of Sydney at Westmead Hospital, Westmead 2145 NSW, Australia
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Lester SJ, Malik R, Bartlett KH, Duncan CG. Cryptococcosis: update and emergence of Cryptococcus gattii. Vet Clin Pathol 2011; 40:4-17. [PMID: 21244455 DOI: 10.1111/j.1939-165x.2010.00281.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Cryptococcosis is a fungal disease that occurs throughout the world. Recent reclassification of Cryptococcus species along with a change in the distribution pattern has prompted reevaluation of the organism and the diseases caused by this pathogen. This review highlights the emergence of Cryptococcus gattii as a primary pathogen in North America and summarizes our current understanding of the disease in mammals and birds.
Collapse
|
37
|
Jung WH, Saikia S, Hu G, Wang J, Fung CKY, D'Souza C, White R, Kronstad JW. HapX positively and negatively regulates the transcriptional response to iron deprivation in Cryptococcus neoformans. PLoS Pathog 2010; 6:e1001209. [PMID: 21124817 PMCID: PMC2991262 DOI: 10.1371/journal.ppat.1001209] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Accepted: 10/25/2010] [Indexed: 11/23/2022] Open
Abstract
The fungal pathogen Cryptococcus neoformans is a major cause of illness in immunocompromised individuals such as AIDS patients. The ability of the fungus to acquire nutrients during proliferation in host tissue and the ability to elaborate a polysaccharide capsule are critical determinants of disease outcome. We previously showed that the GATA factor, Cir1, is a major regulator both of the iron uptake functions needed for growth in host tissue and the key virulence factors such as capsule, melanin and growth at 37°C. We are interested in further defining the mechanisms of iron acquisition from inorganic and host-derived iron sources with the goal of understanding the nutritional adaptation of C. neoformans to the host environment. In this study, we investigated the roles of the HAP3 and HAPX genes in iron utilization and virulence. As in other fungi, the C. neoformans Hap proteins negatively influence the expression of genes encoding respiratory and TCA cycle functions under low-iron conditions. However, we also found that HapX plays both positive and negative roles in the regulation of gene expression, including a positive regulatory role in siderophore transporter expression. In addition, HapX also positively regulated the expression of the CIR1 transcript. This situation is in contrast to the negative regulation by HapX of genes encoding GATA iron regulatory factors in Aspergillus nidulans and Schizosaccharomyces pombe. Although both hapX and hap3 mutants were defective in heme utilization in culture, only HapX made a contribution to virulence, and loss of HapX in a strain lacking the high-affinity iron uptake system did not cause further attenuation of disease. Therefore, HapX appears to have a minimal role during infection of mammalian hosts and instead may be an important regulator of environmental iron uptake functions. Overall, these results indicated that C. neoformans employs multiple strategies for iron acquisition during infection. Cryptococcus neoformans causes life-threatening central nervous system infections in immunocompromised people such as AIDS patients. The competition for iron between pathogens such as C. neoformans and mammalian hosts is a key aspect of disease outcome. We previously identified and characterized the major iron regulatory protein Cir1 in C. neoformans, as well as proteins for the transport of iron-binding molecules (siderophores) and for high-affinity iron uptake. In this study, we examined the roles of additional regulatory proteins (Hap proteins) in the response to low-iron conditions and the use of host iron sources such as heme and transferrin. We discovered that the HapX protein has a conserved regulatory function to repress iron-dependent functions during iron deprivation, as well as a positive regulatory role for the expression of putative siderophore transporters. A hapX mutant was defective in the use of heme as an iron source in culture but was only modestly attenuated for virulence in mice. This result suggests that additional mechanisms for iron uptake must be available to support C. neoformans proliferation in the host, and that HapX may play an important role in environmental iron acquisition.
Collapse
Affiliation(s)
- Won Hee Jung
- Department of Biotechnology, Chung-Ang University, Daedeok-Myeon, Anseong-Si, Gyeonggi-Do, Republic of Korea
| | - Sanjay Saikia
- The Michael Smith Laboratories, Department of Microbiology and Immunology, and Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, Canada
| | - Guanggan Hu
- The Michael Smith Laboratories, Department of Microbiology and Immunology, and Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, Canada
| | - Joyce Wang
- The Michael Smith Laboratories, Department of Microbiology and Immunology, and Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, Canada
| | - Carlen Ka-Yin Fung
- The Michael Smith Laboratories, Department of Microbiology and Immunology, and Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, Canada
| | - Cletus D'Souza
- The Michael Smith Laboratories, Department of Microbiology and Immunology, and Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, Canada
| | - Rick White
- Department of Statistics, University of British Columbia, Vancouver, British Columbia, Canada
| | - James W. Kronstad
- The Michael Smith Laboratories, Department of Microbiology and Immunology, and Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, Canada
- * E-mail:
| |
Collapse
|
38
|
Lockhart SR, Harris J. Cryptococcus gattii: Clinical Importance and Emergence in North America. CURRENT FUNGAL INFECTION REPORTS 2010. [DOI: 10.1007/s12281-010-0021-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
39
|
Li Q, You C, Liu Q, Liu Y. Central nervous system cryptococcoma in immunocompetent patients: a short review illustrated by a new case. Acta Neurochir (Wien) 2010; 152:129-36. [PMID: 19404577 DOI: 10.1007/s00701-009-0311-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2008] [Accepted: 03/31/2009] [Indexed: 02/05/2023]
Abstract
OBJECTIVE Cryptococcal infection in CNS is frequently seen in HIV patients and those with other immunosuppressed conditions. However, cryptococcal granuloma in CNS in immunocompetent patient is rare. We present one new case of cryptococcoma and review literature to illustrate diagnosis and treatment of these lesions. METHODS We conducted literature search in Pubmed search engine of the National Center for Biotechnology Information. RESULTS Seventeen cases of CNS cryptoccoma in immunocompetent patients, including ours, have been reported to date. Of them, two patients had lesions inside spinal cord, and C. neoformans var. gattii was identified in three cases. All patients were symptomatic with normal immunocompetency although two patients had type 2 diabetes mellitus and one had torsades de pointes. Eight patients received surgical treatment and all were given antifungal agents except one suspected of teniasis. CONCLUSIONS With literature reports and our experiences, we suggest that ring shaped enhancement of mass lesion with or without cystic changes in MR scan may indicate cryptococcoma, but definitive diagnosis relies on pathology study of lesion specimen. Open surgery and anti-fungal therapy should be scheduled, and outcome of cryptococcoma is largely determined by its locations.
Collapse
Affiliation(s)
- Qiang Li
- Department of Neurosurgery, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, People's Republic of China
| | | | | | | |
Collapse
|
40
|
Cryptococcus gattii isolates from the British Columbia cryptococcosis outbreak induce less protective inflammation in a murine model of infection than Cryptococcus neoformans. Infect Immun 2009; 77:4284-94. [PMID: 19635827 DOI: 10.1128/iai.00628-09] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The fungal pathogen Cryptococcus neoformans causes approximately one million cases of cryptococcosis per year in people with AIDS. In contrast, the related species C. gattii is responsible for a much smaller number of cases, but these often occur in immunocompetent people. In fact, C. gattii has emerged in the last decade as the frequent cause of cryptococcosis in otherwise healthy people in British Columbia. We analyzed the immune responses elicited by three C. gattii strains and one C. neoformans strain in mice as a first step toward understanding why C. gattii is able to cause disease in immunocompetent hosts. The C. gattii strains all induced a less protective inflammatory response in C57BL/6 mice by inhibiting or failing to provoke the migration of neutrophils to sites of infection. The C. gattii strains also failed to elicit the production of protective cytokines, such as tumor necrosis factor alpha, compared to the ability of the C. neoformans strain. Despite these differences, the strain representing the major outbreak genotype from British Columbia showed a virulence equivalent to that of the C. neoformans strain, while two other C. gattii strains had reduced virulence. Taken together, our results indicate that C. gattii strains thrive in immunocompetent hosts by evading or suppressing the protective immune responses that normally limit the progression of disease caused by C. neoformans.
Collapse
|
41
|
Hu G, Cheng PY, Sham A, Perfect JR, Kronstad JW. Metabolic adaptation in Cryptococcus neoformans during early murine pulmonary infection. Mol Microbiol 2008; 69:1456-75. [PMID: 18673460 DOI: 10.1111/j.1365-2958.2008.06374.x] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
SUMMARY The pathogenic fungus Cryptococcus neoformans generally initiates infection in mammalian lung tissue and subsequently disseminates to the brain. We performed serial analysis of gene expression (SAGE) on C. neoformans cells recovered from the lungs of mice and found elevated expression of genes for central carbon metabolism including functions for acetyl-CoA production and utilization. Deletion of the highly expressed ACS1 gene encoding acetyl-CoA synthetase revealed a requirement for growth on acetate and for full virulence. Transcripts for transporters (e.g. for monosaccharides, iron, copper and acetate) and for stress-response proteins were also elevated thus indicating a nutrient-limited and hostile host environment. The pattern of regulation was reminiscent of the control of alternative carbon source utilization and stress response by the Snf1 protein kinase in Saccharomyces cerevisiae. A snf1 mutant of C. neoformans showed defects in alternative carbon source utilization, the response to nitrosative stress, melanin production and virulence. However, loss of Snf1 did not influence the expression of a set of genes for carbon metabolism that were elevated upon lung infection. Taken together, the results reveal specific metabolic adaptations of C. neoformans during pulmonary infection and indicate a role for ACS1 and SNF1 in virulence.
Collapse
Affiliation(s)
- Guanggan Hu
- Michael Smith Laboratories, The University of British Columbia, 2185 East Mall, Vancouver, BC, Canada
| | | | | | | | | |
Collapse
|
42
|
Oliveira FDM, Severo CB, Guazzelli LS, Severo LC. Cryptococcus gattii fungemia: report of a case with lung and brain lesions mimicking radiological features of malignancy. Rev Inst Med Trop Sao Paulo 2008; 49:263-5. [PMID: 17823759 DOI: 10.1590/s0036-46652007000400014] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2006] [Accepted: 01/09/2007] [Indexed: 12/15/2022] Open
Abstract
A 64-year-old apparently immunocompetent white man developed lung and brain lesions of disseminated cryptococcosis. The radiologic features mimicked those of lung cancer metastatic to the central nervous system. C. gattii was recovered from cultures of bronchoalveolar lavage fluid, brain biopsy, and blood. The same fungus was recovered from pulmonary and brain specimens at autopsy. Serum and cerebrospinal fluid cryptococcal antigen tests were diagnostic in our case and should be included in the diagnostic evaluation of unexplained pulmonary and cerebral lesions. A literature search showed few reports of fungemia by this species of Cryptococcus, contrasting to C. neoformans.
Collapse
Affiliation(s)
- Flávio de Mattos Oliveira
- Programa de Pós-Graduação em Pneumologia - Mestrado e Doutorado, Universidade Federal do Rio Grande do Sul, Brasil
| | | | | | | |
Collapse
|
43
|
Wright LC, Santangelo RM, Ganendren R, Payne J, Djordjevic JT, Sorrell TC. Cryptococcal lipid metabolism: phospholipase B1 is implicated in transcellular metabolism of macrophage-derived lipids. EUKARYOTIC CELL 2006; 6:37-47. [PMID: 17099081 PMCID: PMC1800365 DOI: 10.1128/ec.00262-06] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Cryptococci survive and replicate within macrophages and can use exogenous arachidonic acid for the production of eicosanoids. Phospholipase B1 (PLB1) has a putative, but uninvestigated, role in these processes. We have shown that uptake and esterification of radiolabeled arachidonic, palmitic, and oleic acids by the Cryptococcus neoformans var. grubii H99 wild-type strain and its PLB1 deletion mutant strain (the Deltaplb1 strain) are independent of PLB1, except under hyperosmolar stress. Similarly, PLB1 was required for metabolism of 1-palmitoyl lysophosphatidylcholine (LysoPC), which is toxic to eukaryotic cell membranes, under hyperosmolar conditions. During both logarithmic and stationary phases of growth, the physiologically relevant phospholipids, dipalmitoyl phosphatidylcholine (DPPC) and dioleoyl phosphatidylcholine, were taken up and metabolized via PLB1. Exogenous DPPC did not enhance growth in the presence of glucose as a carbon source but could support it for at least 24 h in glucose-free medium. Detoxification of LysoPC by reacylation occurred in both the H99 wild-type and the Deltaplb1 strains in the presence of glucose, but PLB1 was required when LysoPC was the sole carbon source. This indicates that both energy-independent (via PLB1) and energy-dependent transacylation pathways are active in cryptococci. Phospholipase A(1) activity was identified by PLB1-independent degradation of 1-palmitoyl-2-arachidonoyl phosphatidylcholine, but the arachidonoyl LysoPC formed was not detoxified by reacylation. Using the human macrophage-like cell line THP-1, we demonstrated the PLB1-dependent incorporation of macrophage-derived arachidonic acid into cryptococcal lipids during cryptococcus-phagocyte interaction. This pool of arachidonate can be sequestered for eicosanoid production by the fungus and/or suppression of host phagocytic activity, thus diminishing the immune response.
Collapse
Affiliation(s)
- Lesley C Wright
- Centre for Infectious Diseases and Microbiology, Level 3, ICPMR Building, Westmead Hospital, Westmead NSW 2145, Australia.
| | | | | | | | | | | |
Collapse
|
44
|
Lester SJ, Kowalewich NJ, Bartlett KH, Krockenberger MB, Fairfax TM, Malik R. Clinicopathologic features of an unusual outbreak of cryptococcosis in dogs, cats, ferrets, and a bird: 38 cases (January to July 2003). J Am Vet Med Assoc 2004; 225:1716-22. [PMID: 15626222 DOI: 10.2460/javma.2004.225.1716] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine clinical and pathologic findings associated with an outbreak of cryptococcosis in an unusual geographic location (British Columbia, Canada). DESIGN Retrospective study. ANIMALS 1 pink-fronted cockatoo, 2 ferrets, 20 cats, and 15 dogs. PROCEDURE A presumptive diagnosis of cryptococcosis was made on the basis of serologic, histopathologic, or cytologic findings, and a definitive diagnosis was made on the basis of culture or immunohistochemical staining. RESULTS No breed or sex predilections were detected in affected dogs or cats. Eleven cats had neurologic signs, 7 had skin lesions, and 5 had respiratory tract signs. None of 17 cats tested serologically for FeLV yielded positive results; 1 of 17 cats yielded positive results for FIV (western blot). Nine of 15 dogs had neurologic signs, 2 had periorbital swellings, and only 3 had respiratory tract signs initially. Microbiologic culture in 15 cases yielded 2 isolates of Cryptococcus neoformans var grubii (serotype A) and 13 isolates of C. neoformans var gattii (serotype B); all organisms were susceptible to amphotericin B and ketoconazole. Serologic testing had sensitivity of 92% and specificity of 98%. CONCLUSIONS AND CLINICAL RELEVANCE Serologic titers were beneficial in identifying infection in animals with nonspecific signs, but routine serum biochemical or hematologic parameters were of little value in diagnosis. Most animals had nonspecific CNS signs and represented a diagnostic challenge. Animals that travel to or live in this region and have nonspecific malaise or unusual neurologic signs should be evaluated for cryptococcosis.
Collapse
Affiliation(s)
- Sally J Lester
- Central Laboratory for Veterinarians, 5645 199th St, Langley, BC V3A 1H9, Canada
| | | | | | | | | | | |
Collapse
|
45
|
Ganendren R, Widmer F, Singhal V, Wilson C, Sorrell T, Wright L. In vitro antifungal activities of inhibitors of phospholipases from the fungal pathogen Cryptococcus neoformans. Antimicrob Agents Chemother 2004; 48:1561-9. [PMID: 15105106 PMCID: PMC400561 DOI: 10.1128/aac.48.5.1561-1569.2004] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Secreted phospholipase B is a proven virulence factor for the pathogenic fungus Cryptococcus neoformans and exhibits three phospholipase activities in the one protein. These are phospholipase B (PLB), lysophospholipase (LPL), and lysophospholipase transacylase (LPTA). Our aim was to investigate the feasibility of using this enzyme as a target for antifungal therapy. We determined in C. neoformans var. grubii strain H99 that 82% of PLB activity was secreted but that 64% of LPL activity and 70% of LPTA activity were cell associated. Cell-associated activities (cytosolic and membrane) were further characterized, since it is likely that any fungicidal effect would depend on inhibition of these enzymes. Four commercially available compounds with structural similarities to phospholipid substrates were tested as inhibitors. These were alexidine dihydrochloride (compound A), dioctadecyldimethylammonium bromide (compound O), 1,12 bis-(tributylphosphonium)dodecane dibromide (compound P), and decamethonium dibromide (compound D). The best phospholipase inhibitors (compounds A and P) were also the most potent antifungal agents by the standard broth microdilution test. Compound A was highly selective for secreted and cell-associated PLB activities and showed no inhibition of mammalian phospholipase A(2) at 0.25 micro M. Compound O, which was specific for secretory and cytosolic LPL and LPTA and membrane-associated PLB, was not antifungal. We conclude that inhibitors of cryptococcal phospholipases can be selective for fungal enzymes and intrinsically antifungal. They also provide tools for assessing the relative importance of the various enzyme activities in virulence. Our results enable further rational structure-function studies to validate the use of phospholipases as antifungal targets.
Collapse
Affiliation(s)
- Ranjini Ganendren
- Centre for Infectious Diseases and Microbiology, University of Sydney at Westmead, and Department of Infectious Diseases, Westmead Hospital, Westmead, NSW 2145, Australia
| | | | | | | | | | | |
Collapse
|
46
|
Santangelo R, Zoellner H, Sorrell T, Wilson C, Donald C, Djordjevic J, Shounan Y, Wright L. Role of extracellular phospholipases and mononuclear phagocytes in dissemination of cryptococcosis in a murine model. Infect Immun 2004; 72:2229-39. [PMID: 15039347 PMCID: PMC375158 DOI: 10.1128/iai.72.4.2229-2239.2004] [Citation(s) in RCA: 133] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2003] [Revised: 09/24/2003] [Accepted: 01/09/2004] [Indexed: 11/20/2022] Open
Abstract
Secreted phospholipase B (PLB) activity promotes the survival and replication of Cryptococcus neoformans in macrophages in vitro. We therefore investigated the role of mononuclear phagocytes and cryptococcal PLB in the dissemination of infection in a mouse model, using C. neoformans var. grubii wild-type strain H99, a PLB1 deletion mutant (Delta plb1), and a reconstituted strain (Delta plb1(rec)). PLB facilitated the entry of endotracheally administered cryptococci into lung IM. PLB was also required for lymphatic spread from the lung to regional lymph nodes and for entry into the blood. Langhans-type giant cells containing budding cryptococci were seen free in the lymphatic sinuses of hilar nodes of H99- and Delta plb1(rec)-infected mice, suggesting that they may have a role in the dissemination of cryptococcal infection. The transfer of infected lung macrophages to recipient mice by tail vein injections demonstrated that these cells can facilitate hematogenous dissemination of cryptococci to the brain, independent of cryptococcal PLB secretion. PLB activities of cryptococci isolated from lung macrophages or infected brains were not persistently increased. We conclude that mononuclear phagocytes are a vehicle for cryptococcal dissemination and that PLB activity is necessary for the initiation of interstitial pulmonary infections and for dissemination from the lung via the lymphatics and blood. PLB is not, however, essential for the establishment of neurological infections when cryptococci are presented within, or after passage through, mononuclear phagocytes.
Collapse
Affiliation(s)
- Rosemary Santangelo
- Centre for Infectious Diseases and Microbiology, University of Sydney at Westmead and Department of Infectious Diseases, Westmead Hospital, NSW 2145, Australia
| | | | | | | | | | | | | | | |
Collapse
|
47
|
Current awareness on yeast. Yeast 2003; 20:653-60. [PMID: 12769126 DOI: 10.1002/yea.945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
|
48
|
Himmelreich U, Allen C, Dowd S, Malik R, Shehan BP, Mountford C, Sorrell TC. Identification of metabolites of importance in the pathogenesis of pulmonary cryptococcoma using nuclear magnetic resonance spectroscopy. Microbes Infect 2003; 5:285-90. [PMID: 12706441 DOI: 10.1016/s1286-4579(03)00028-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Primary lung infection with Cryptococcus neoformans is characterised by circumscribed lesions (cryptococcomas). To identify cryptococcal and/or host products of importance in pathogenesis, we applied proton nuclear magnetic resonance (NMR) spectroscopy, which identifies mobile compounds present in complex mixtures, to experimental pulmonary cryptococcomas from rats. Magnetic resonance experiments were performed on cryptococcomas (n = 10) and healthy lungs (n = 8). Signal assignment to key metabolites was confirmed by homo-nuclear and hetero-nuclear NMR correlation spectroscopy. Cryptococcal metabolites, dominating spectra from cryptococcomas included the stress protectants, trehalose and mannitol, acetate, and in some animals, ethanol. Glycerophosphorylcholine was also abundant in cryptococcomas, consistent with hydrolysis of phospholipids in vivo by the cryptococcal enzyme, phospholipase B (PLB). PLB has been identified by molecular studies as a cryptococcal virulence determinant. We propose that PLB secreted by cryptococci promotes tissue invasion by hydrolysing host phospholipids, such as dipalmitoyl phosphatidyl choline, which is abundant in pulmonary surfactant, and lung cell membrane phospholipids. Our results confirm the utility of NMR spectroscopy in studies of microbial pathogenesis.
Collapse
Affiliation(s)
- Uwe Himmelreich
- Centre for Infectious Diseases and Microbiology, University of Sydney at Westmead Hospital, Room 3114, Level 3, ICPMR, Darcy Road, Westmead, NSW 2145, Australia
| | | | | | | | | | | | | |
Collapse
|