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Shi R, Lin X. Illuminating the Cryptococcus neoformans species complex: unveiling intracellular structures with fluorescent-protein-based markers. Genetics 2024; 227:iyae059. [PMID: 38752295 PMCID: PMC11228865 DOI: 10.1093/genetics/iyae059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 04/06/2024] [Indexed: 07/09/2024] Open
Abstract
Cryptococcus neoformans is a fungal pathogen of the top critical priority recognized by the World Health Organization. This clinically important fungus also serves as a eukaryotic model organism. A variety of resources have been generated to facilitate investigation of the C. neoformans species complex, including congenic pairs, well-annotated genomes, genetic editing tools, and gene deletion sets. Here, we generated a set of strains with all major organelles fluorescently marked. We tested short organelle-specific targeting sequences and successfully labeled the following organelles by fusing the targeting sequences with a fluorescence protein: the plasma membrane, the nucleus, the peroxisome, and the mitochondrion. We used native cryptococcal Golgi and late endosomal proteins fused with a fluorescent protein to label these two organelles. These fluorescence markers were verified via colocalization using organelle-specific dyes. All the constructs for the fluorescent protein tags were integrated in an intergenic safe haven region. These organelle-marked strains were examined for growth and various phenotypes. We demonstrated that these tagged strains could be employed to track cryptococcal interaction with the host in phagocytosis assays. These strains also allowed us to discover remarkable differences in the dynamics of proteins targeted to different organelles during sexual reproduction. Additionally, we revealed that "dormant" spores transcribed and synthesized their own proteins and trafficked the proteins to the appropriate subcellular compartments, demonstrating that spores are metabolically active. We anticipate that these newly generated fluorescent markers will greatly facilitate further investigation of cryptococcal biology and pathogenesis.
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Affiliation(s)
- Ran Shi
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA
| | - Xiaorong Lin
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA
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2
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Smith-Peavler E, Sircy LM, Nelson DE, McClelland EE. Two Methods of Measuring Cryptococcus neoformans Fungal Burden in Macrophages. Methods Mol Biol 2024; 2775:211-221. [PMID: 38758320 DOI: 10.1007/978-1-0716-3722-7_14] [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: 05/18/2024]
Abstract
The ability of C. neoformans to survive and replicate within host phagocytes enables it to evade the immune system and allows for persistence of the infection. As such, measuring fungal burden of C. neoformans strains-and indeed how drug treatments can influence fungal burden-provides important information about C. neoformans pathogenesis. In this chapter, we describe two methods that may be used to appraise fungal burden: a standard end-point colony-formation assay for calculating the average number of yeast per host cell and a fluorescence microscopy-based method that may be used to measure changes in fungal burden in individual living macrophages in real time.
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Affiliation(s)
- Emily Smith-Peavler
- Department of Biology, Middle Tennessee State University, Murfreesboro, TN, USA
- KIPP Collegiate High School, Nashville, TN, USA
| | - Linda M Sircy
- Department of Biology, Middle Tennessee State University, Murfreesboro, TN, USA
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Salt Lake City, UT, USA
| | - David E Nelson
- Department of Biology, Middle Tennessee State University, Murfreesboro, TN, USA
| | - Erin E McClelland
- Department of Biomedical Sciences, Marian University College of Osteopathic Medicine, Indianapolis, IN, USA.
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3
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Vu K, Buckley BJ, Bujaroski RS, Blumwald E, Kelso MJ, Gelli A. Antifungal activity of 6-substituted amiloride and hexamethylene amiloride (HMA) analogs. Front Cell Infect Microbiol 2023; 13:1101568. [PMID: 36923593 PMCID: PMC10009331 DOI: 10.3389/fcimb.2023.1101568] [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: 11/18/2022] [Accepted: 01/20/2023] [Indexed: 02/19/2023] Open
Abstract
Fungal infections have become an increasing threat as a result of growing numbers of susceptible hosts and diminishing effectiveness of antifungal drugs due to multi-drug resistance. This reality underscores the need to develop novel drugs with unique mechanisms of action. We recently identified 5-(N,N-hexamethylene)amiloride (HMA), an inhibitor of human Na+/H+ exchanger isoform 1, as a promising scaffold for antifungal drug development. In this work, we carried out susceptibility testing of 45 6-substituted HMA and amiloride analogs against a panel of pathogenic fungi. A series of 6-(2-benzofuran)amiloride and HMA analogs that showed up to a 16-fold increase in activity against Cryptococcus neoformans were identified. Hits from these series showed broad-spectrum activity against both basidiomycete and ascomycete fungal pathogens, including multidrug-resistant clinical isolates.
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Affiliation(s)
- Kiem Vu
- Department of Pharmacology, School of Medicine, University of California, Genome and Biomedical Sciences Facility, Davis, CA, United States
| | - Benjamin J. Buckley
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia
| | - Richard S. Bujaroski
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia
- Monash Institute of Pharmaceutical Science (ATMCF), Monash University, Parkville, VIC, Australia
| | - Eduardo Blumwald
- Department of Plant Sciences, PRB Building, University of California, Davis, CA, Australia
| | - Michael J. Kelso
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia
| | - Angie Gelli
- Department of Pharmacology, School of Medicine, University of California, Genome and Biomedical Sciences Facility, Davis, CA, United States
- *Correspondence: Angie Gelli,
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4
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Markandan K, Tiong YW, Sankaran R, Subramanian S, Markandan UD, Chaudhary V, Numan A, Khalid M, Walvekar R. Emergence of infectious diseases and role of advanced nanomaterials in point-of-care diagnostics: a review. Biotechnol Genet Eng Rev 2022:1-89. [PMID: 36243900 DOI: 10.1080/02648725.2022.2127070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 09/12/2022] [Indexed: 11/09/2022]
Abstract
Infectious outbreaks are the foremost global public health concern, challenging the current healthcare system, which claims millions of lives annually. The most crucial way to control an infectious outbreak is by early detection through point-of-care (POC) diagnostics. POC diagnostics are highly advantageous owing to the prompt diagnosis, which is economical, simple and highly efficient with remote access capabilities. In particular, utilization of nanomaterials to architect POC devices has enabled highly integrated and portable (compact) devices with enhanced efficiency. As such, this review will detail the factors influencing the emergence of infectious diseases and methods for fast and accurate detection, thus elucidating the underlying factors of these infections. Furthermore, it comprehensively highlights the importance of different nanomaterials in POCs to detect nucleic acid, whole pathogens, proteins and antibody detection systems. Finally, we summarize findings reported on nanomaterials based on advanced POCs such as lab-on-chip, lab-on-disc-devices, point-of-action and hospital-on-chip. To this end, we discuss the challenges, potential solutions, prospects of integrating internet-of-things, artificial intelligence, 5G communications and data clouding to achieve intelligent POCs.
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Affiliation(s)
- Kalaimani Markandan
- Temasek Laboratories, Nanyang Technological University, Nanyang Drive, Singapore
- Faculty of Engineering, Technology and Built Environment, UCSI University, Kuala Lumpur, Malaysia
| | - Yong Wei Tiong
- NUS Environmental Research Institute, National University of Singapore, Engineering Drive, Singapore
| | - Revathy Sankaran
- Graduate School, University of Nottingham Malaysia Campus, Semenyih, Selangor, Malaysia
| | - Sakthinathan Subramanian
- Department of Materials & Mineral Resources Engineering, National Taipei University of Technology (NTUT), Taipei, Taiwan
| | | | - Vishal Chaudhary
- Research Cell & Department of Physics, Bhagini Nivedita College, University of Delhi, New Delhi, India
| | - Arshid Numan
- Graphene & Advanced 2D Materials Research Group (GAMRG), School of Engineering and Technology, Sunway University, Petaling Jaya, Selangor, Malaysia
- Sunway Materials Smart Science & Engineering (SMS2E) Research Cluster School of Engineering and Technology, Sunway University, Selangor, Malaysia
| | - Mohammad Khalid
- Graphene & Advanced 2D Materials Research Group (GAMRG), School of Engineering and Technology, Sunway University, Petaling Jaya, Selangor, Malaysia
- Sunway Materials Smart Science & Engineering (SMS2E) Research Cluster School of Engineering and Technology, Sunway University, Selangor, Malaysia
| | - Rashmi Walvekar
- Department of Chemical Engineering, School of Energy and Chemical Engineering, Xiamen University Malaysia, Sepang, Selangor, Malaysia
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5
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Pathogenesis of Fungal Infections in the Central Nervous System: Host and Pathogen Factors in Neurotropism. CURRENT FUNGAL INFECTION REPORTS 2022. [DOI: 10.1007/s12281-022-00444-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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6
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Haider MS, Master M, Mahtani A, Guzzo E, Khalil A. Cryptococcal Pneumonia in an Immunocompetent Patient: A Rare Occurrence. Cureus 2022; 14:e29841. [PMID: 36348868 PMCID: PMC9632677 DOI: 10.7759/cureus.29841] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/02/2022] [Indexed: 11/05/2022] Open
Abstract
Cryptococcosis is an invasive yeast infection commonly found among immunosuppressed patients. Pulmonary cryptococcal infection can have variable presentations ranging from pulmonary nodules and masses to consolidation. A patient can present with shortness of breath, cough, sputum production, chest pain, fatigue, and weight loss. Diagnosis can be made using fungal culture, histology, radiographic findings, and cryptococcal antigen in serum as well as in the cerebrospinal fluid. Treatment is usually with a combination or a single antifungal agent. Few cases have been reported in immunocompetent individuals. Here we present a case of 69-year-old immunocompetent individual, who was initially seen in the outpatient clinic for dyspnea, cough, and fatigue and was treated for pneumonia. The patient remained symptomatic despite multiple courses of oral antibiotics. He was then sent for inpatient admission. CT scan was obtained that showed patchy infiltrates and consolidations, followed by bronchoscopy. The cytology confirmed adenocarcinoma. The fungal smear and culture grew Cryptococcus neoformans. The patient was treated with fluconazole with improvement of his symptoms before starting chemotherapy. We are reporting this case as clinicians usually focus on bacterial etiologies in outpatient setting. Our patient, who was immunocompetent, had a new diagnosis of cryptococcal pneumonia and was also found to have lung adenocarcinoma. This case highlights the rare occurrence of this type of pneumonia in immunocompetent patients and the importance of considering fungal causes of pneumonia in patients.
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Georgakopoulou VE, Damaskos C, Sklapani P, Trakas N, Gkoufa A. Pleural involvement in cryptococcal infection. World J Clin Cases 2022; 10:5510-5514. [PMID: 35812673 PMCID: PMC9210898 DOI: 10.12998/wjcc.v10.i16.5510] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 03/30/2022] [Accepted: 04/30/2022] [Indexed: 02/06/2023] Open
Abstract
Pleural involvement of cryptococcal infection is uncommon and is more commonly observed in immunocompromised hosts than in immunocompetent ones. Pleural involvement in cryptococcal infections can manifest with or without pleural effusion. The presence of Cryptococcus spp. in the effusion or pleura is required for the diagnosis of cryptococcal pleural infection, which is commonly determined by pleural biopsy, fluid culture, and/or detection of cryptococcal antigen in the pleura or pleural fluid.
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Affiliation(s)
| | - Christos Damaskos
- Department of Infectious Diseases, Laiko General Hospital, Athens 11527, Greece
| | - Pagona Sklapani
- Department of Infectious Diseases, Laiko General Hospital, Athens 11527, Greece
| | - Nikolaos Trakas
- Department of Infectious Diseases, Laiko General Hospital, Athens 11527, Greece
| | - Aikaterini Gkoufa
- Department of Infectious Diseases, Laiko General Hospital, Athens 11527, Greece
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8
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Bryan AM, You JK, Li G, Kim J, Singh A, Morstein J, Trauner D, Pereira de Sá N, Normile TG, Farnoud AM, London E, Del Poeta M. Cholesterol and sphingomyelin are critical for Fcγ receptor-mediated phagocytosis of Cryptococcus neoformans by macrophages. J Biol Chem 2021; 297:101411. [PMID: 34793834 PMCID: PMC8661020 DOI: 10.1016/j.jbc.2021.101411] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 11/04/2021] [Accepted: 11/11/2021] [Indexed: 12/21/2022] Open
Abstract
Cryptococcus neoformans is a fungal pathogen that causes life-threatening meningoencephalitis in lymphopenic patients. Pulmonary macrophages comprise the first line of host defense upon inhalation of fungal spores by aiding in clearance but can also potentially serve as a niche for their dissemination. Given that macrophages play a key role in the outcome of a cryptococcal infection, it is crucial to understand factors that mediate phagocytosis of C. neoformans. Since lipid rafts (high-order plasma membrane domains enriched in cholesterol and sphingomyelin [SM]) have been implicated in facilitating phagocytosis, we evaluated whether these ordered domains govern macrophages' ability to phagocytose C. neoformans. We found that cholesterol or SM depletion resulted in significantly deficient immunoglobulin G (IgG)-mediated phagocytosis of fungus. Moreover, repletion of macrophage cells with a raft-promoting sterol (7-dehydrocholesterol) rescued this phagocytic deficiency, whereas a raft-inhibiting sterol (coprostanol) significantly decreased IgG-mediated phagocytosis of C. neoformans. Using a photoswitchable SM (AzoSM), we observed that the raft-promoting conformation (trans-AzoSM) resulted in efficient phagocytosis, whereas the raft-inhibiting conformation (cis-AzoSM) significantly but reversibly blunted phagocytosis. We observed that the effect on phagocytosis may be facilitated by Fcγ receptor (FcγR) function, whereby IgG immune complexes crosslink to FcγRIII, resulting in tyrosine phosphorylation of FcR γ-subunit (FcRγ), an important accessory protein in the FcγR signaling cascade. Correspondingly, cholesterol or SM depletion resulted in decreased FcRγ phosphorylation. Repletion with 7-dehydrocholesterol restored phosphorylation, whereas repletion with coprostanol showed FcRγ phosphorylation comparable to unstimulated cells. Together, these data suggest that lipid rafts are critical for facilitating FcγRIII-mediated phagocytosis of C. neoformans.
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Affiliation(s)
- Arielle M Bryan
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, USA
| | - Jeehyun Karen You
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, USA
| | - Guangtao Li
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, USA
| | - JiHyun Kim
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, USA
| | - Ashutosh Singh
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, USA
| | - Johannes Morstein
- Department of Chemistry, New York University, New York, New York, USA
| | - Dirk Trauner
- Department of Chemistry, New York University, New York, New York, USA
| | - Nívea Pereira de Sá
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, USA
| | - Tyler G Normile
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, USA
| | - Amir M Farnoud
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, USA
| | - Erwin London
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, USA
| | - Maurizio Del Poeta
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, USA; Division of Infectious Diseases, Stony Brook University, Stony Brook, New York, USA; Veteran Affairs Medical Center, Northport, New York, USA.
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9
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Dangarembizi R. Reimagining the future of African brain health: Perspectives for basic research on the pathogenesis of cryptococcal meningitis. Brain Behav Immun Health 2021; 18:100388. [PMID: 34825235 PMCID: PMC8605210 DOI: 10.1016/j.bbih.2021.100388] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 10/28/2021] [Accepted: 11/05/2021] [Indexed: 11/24/2022] Open
Abstract
Cryptococcal meningitis is a fatal opportunistic infection of the brain and a leading cause of neurological damage and death in immunocompromised individuals. This neglected fungal disease of the brain is a huge burden on the health systems of developing countries, especially in Sub-Saharan Africa, where up to 25% of people living with HIV/AIDS succumb to it. Cryptococcal fungal cells have a predilection for the brain and they are capable of traversing the blood brain barrier and invade the brain where they cause infection, inflammation and a disruption of normal brain function. A robust host neuroimmune response is critical for pathogen clearance and survival, and a good understanding of the mechanisms underlying its development in the host is critical for the development of effective treatments. However, past basic research studies have been focussed on the characteristics of the fungus and its effect on the peripheral immune system; with little attention paid to how it interacts with brain immune cells. This mini review briefly discusses the paucity of basic research data on the neuroimmune response to cryptococcal infection, raises pertinent questions on how the brain cells respond to the fungal infection, and thereafter discusses models, techniques and advanced technologies that could be useful for carrying out high-throughput research on the pathogenesis of cryptococcal meningitis.
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Affiliation(s)
- R Dangarembizi
- Division of Physiological Sciences, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Neuroscience Institute, Faculty of Health Sciences, University of Cape Town, Groote Schuur Hospital, Cape Town, South Africa
- CMM AFRICA Medical Mycology Research Unit, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
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10
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Khwantongyim P, Wansee S, Lu X, Zhang W, Sun G. Variations in the Community Structure of Fungal Microbiota Associated with Apple Fruit Shaped by Fruit Bagging-Based Practice. J Fungi (Basel) 2021; 7:jof7090764. [PMID: 34575802 PMCID: PMC8470174 DOI: 10.3390/jof7090764] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 09/05/2021] [Accepted: 09/13/2021] [Indexed: 11/26/2022] Open
Abstract
The various fungal communities that adhere to apple fruit are influenced by agricultural practices. However, the effects of fruit bagging-based management practice on the fungal microbiota are still unknown, and little is known about the fungal communities of bagged apple fruit. We conducted a study using apple fruit grown in a conventionally managed orchard where pesticide use is an indispensable practice. Fungal communities were collected from the calyx-end and peel tissues of bagged and unbagged fruit and characterized using barcode-type next-generation sequencing. Fruit bagging had a stronger effect on fungal richness, abundance, and diversity of the fungal microbiota in comparison to non-bagging. In addition, bagging also impacted the compositional variation of the fungal communities inhabiting each fruit part. We observed that fruit bagging had a tendency to maintain ecological equilibrium since Ascomycota and Basidiomycota were more distributed in bagged fruit than in unbagged fruit. These fungal communities consist of beneficial fungi rather than potentially harmful fungi. Approximately 50 dominant taxa were detected in bagged fruit, for example, beneficial genera such as Articulospora, Bullera, Cryptococcus, Dioszegia, Erythrobasidium, and Sporobolomyces, as well as pathogenic genera such as Aureobasidium and Taphrina. These results suggested that fruit bagging could significantly increase fungal richness and promote healthy fungal communities, especially the harmless fungal communities, which might be helpful for protecting fruit from the effects of pathogens. This study provides a foundation for understanding the impacts of bagging-based practice on the associated fungal microbiota.
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Johns LE, Goldman GH, Ries LN, Brown NA. Nutrient sensing and acquisition in fungi: mechanisms promoting pathogenesis in plant and human hosts. FUNGAL BIOL REV 2021. [DOI: 10.1016/j.fbr.2021.01.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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12
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Aviel YB, Ofir A, Ben-Izhak O, Vlodavsky E, Karbian N, Brik R, Mevorach D, Magen D. A novel loss-of-function mutation in LACC1 underlies hereditary juvenile arthritis with extended intra-familial phenotypic heterogeneity. Rheumatology (Oxford) 2021; 60:4888-4898. [PMID: 33493343 DOI: 10.1093/rheumatology/keab017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Accepted: 11/19/2020] [Indexed: 01/02/2023] Open
Abstract
OBJECTIVE To investigate phenotypic and molecular characteristics of a consanguineous family with autosomal-recessive, polyarticular, juvenile idiopathic arthritis (JIA) with extra-articular manifestations, including renal amyloidosis and Crohn's disease, associated with a novel homozygous truncating variant in LACC1. METHODS Whole exome sequencing (WES) or targeted Sanger verification were performed in 15 participants. LACC1 expression and cytokine array were analyzed in patient-derived and CRISPR/Cas9-generated LACC1-knockout macrophages (Mϕ). RESULTS A homozygous truncating variant (p.Glu348Ter) in LACC1 was identified in three affected and one asymptomatic family member, and predicted harmful by causing premature stop of the LACC1 protein sequences, and by absence from ethnically-matched controls and public variation databases. Expression studies in patient-derived macrophages (Mϕ) showed no endogenous p. Glu348Ter-LACC1 RNA transcription or protein expression, compatible with nonsense-mediated mRNA decay. WES analysis in the asymptomatic homozygous subject for p. Glu348Ter-LACC1 detected an exclusive heterozygous variant (p.Arg928Gln) in complement component C5. Further complement activity analysis suggested a protective role for the p. Arg928Gln-C5 variant as a phenotypic modifier of LACC1-associated disease. Finally, cytokine profile analysis indicated increased levels of pro-inflammatory cytokines in LACC1-disrupted as compared with wild-type Mϕ. CONCLUSIONS Our findings reinforce the role of LACC1 disruption in autosomal-recessive JIA, extend the clinical spectrum and intra-familial heterogeneity of the disease-associated phenotype, indicate a modulatory effect of complement factor C5 on phenotypic severity, and suggest an inhibitory role for wild-type LACC1 on pro-inflammatory pathways.
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Affiliation(s)
- Yonatan Butbul Aviel
- Department of Pediatrics and Pediatric Rheumatology Service, Ruth Children's Hospital, Rambam Health Care Campus, Haifa, Israel.,Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Ayala Ofir
- Laboratory of Molecular Medicine, Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Ofer Ben-Izhak
- Department of Pathology, Rambam Health Care Campus, Haifa, Israel.,Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Euvgeni Vlodavsky
- Department of Pathology, Rambam Health Care Campus, Haifa, Israel.,Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Netanel Karbian
- Rheumatology Research Center, Department of Medicine, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Riva Brik
- Department of Pediatrics and Pediatric Rheumatology Service, Ruth Children's Hospital, Rambam Health Care Campus, Haifa, Israel.,Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Dror Mevorach
- Rheumatology Research Center, Department of Medicine, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Daniella Magen
- Laboratory of Molecular Medicine, Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel.,Pediatric Nephrology Institute, Ruth Children's Hospital, Rambam Health Care Campus, Haifa, Israel
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13
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Nathan CL, Emmert BE, Nelson E, Berger JR. CNS fungal infections: A review. J Neurol Sci 2021; 422:117325. [PMID: 33516057 DOI: 10.1016/j.jns.2021.117325] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 12/23/2020] [Accepted: 01/19/2021] [Indexed: 11/19/2022]
Affiliation(s)
- Cody L Nathan
- Departments of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Brian E Emmert
- Departments of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Ernest Nelson
- Departments of Pathology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Joseph R Berger
- Departments of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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14
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Nematollahi S, Dioverti-Prono V. Cryptococcal infection in haematologic malignancies and haematopoietic stem cell transplantation. Mycoses 2020; 63:1033-1046. [PMID: 32740974 DOI: 10.1111/myc.13153] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 07/22/2020] [Accepted: 07/23/2020] [Indexed: 12/18/2022]
Abstract
This review summarises both the recent and relevant studies about cryptococcal infections in haematologic malignancies and haematopoietic stem cell transplantation. Although uncommon in this patient population, this infection carries a high mortality, especially if left untreated. Given the limited data, we draw some conclusions with respect to management from the solid organ transplantation and HIV-infected literature. Herein, we discuss cryptococcosis with a particular attention to its background, epidemiology, risk factors, clinical presentation, diagnosis, treatment and prevention in this group.
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Affiliation(s)
- Saman Nematollahi
- Department of Medicine, Division of Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Veronica Dioverti-Prono
- Department of Medicine, Division of Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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15
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Incorporation of 2-amino-thiophene derivative in nanoparticles: enhancement of antifungal activity. Braz J Microbiol 2020; 51:647-655. [PMID: 32141030 DOI: 10.1007/s42770-020-00248-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Accepted: 02/18/2020] [Indexed: 01/08/2023] Open
Abstract
The objective of this study was to evaluate the effects of nanoparticles (nanospheres and nanocapsules) of the promising antifungal 2-amino-thiophene (6CN10) and 6CN10 complexed with 2-hydroxypropyl-β-cyclodextrin (6CN10:HP-β-CD) in vitro and compared with free drug against Candida and Cryptococcus, using a microdilution method to measure susceptibility. The Candida and Cryptococcus clinical strains were identified using phenotypic methods and matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF). To measure in vitro antifungal susceptibility, we used microdilution trials. Serial drug or nanoparticle dilutions were prepared according to the CLSI M27-A3 guidelines. Anti-biofilm activity was verified for Cryptococcus neoformans. All Candida isolates were sensitive to the free drug (MIC = 41.66-333.33 μg/mL) and were able to grow even at the higher concentration tested for all 6CN10 nanoparticles. However, the Cryptococcus neoformans strains presented MIC values of 0.32-83.33 μg/mL for 6CN10 nanoparticles, and MIC values of 0.1-0.2 μg/mL for 6CN10:HP-β-CD nanoparticles, i.e., 3333 times more active than the free drug (MIC values 166.66-333.33 μg/mL), and presenting activity greater than that of the reference drug amphotericin B (MIC = 0.5-0.125 μg/mL). 6CN10:HP-β-CD nanosphere also showed high anti-biofilm potential. The in vitro study showed that the nanoparticles allowed better drug efficiency against Cryptococcus than did the free drug. These results suggest that 6CN10-loaded nanoparticles may become a future alternative for cryptococcosis and candidiasis therapy. In vivo experiments are essential prior to clinical use.
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Setianingrum F, Rautemaa-Richardson R, Denning DW. Pulmonary cryptococcosis: A review of pathobiology and clinical aspects. Med Mycol 2019; 57:133-150. [PMID: 30329097 DOI: 10.1093/mmy/myy086] [Citation(s) in RCA: 132] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 09/05/2018] [Indexed: 01/13/2023] Open
Abstract
Pulmonary cryptococcosis is an important opportunistic invasive mycosis in immunocompromised patients, but it is also increasingly seen in immunocompetent patients. The main human pathogens are Cryptococcus neoformans and C. gattii, which have a worldwide distribution. In contrast to cryptococcal meningitis, pulmonary cryptococcosis is still underdiagnosed because of limitations in diagnostic tools. It can mimic lung cancer, pulmonary tuberculosis, bacterial pneumonia, and other pulmonary mycoses both clinically and radiologically. Pulmonary nodules are the most common radiological feature, but these are not specific to pulmonary cryptococcosis. The sensitivity of culture of respiratory samples for Cryptococcus is poor and a positive result may also reflect colonisation. Cryptococcal antigen (CrAg) with lateral flow device is a fast and sensitive test and widely used on serum and cerebrospinal fluid, but sera from patients with pulmonary cryptococcosis are rarely positive in the absence of disseminated disease. Detection of CrAg from respiratory specimens might assist the diagnosis of pulmonary cryptococcosis but there are very few data. Molecular detection techniques such as multiplex reverse transcription polymerase chain reaction (RT-PCR) could also provide better sensitivity but these still require validation for respiratory specimens. The first line of treatment for pulmonary cryptococcosis is fluconazole, or amphotericin B and flucytosine for those with central nervous system involvement. Pulmonary cryptococcosis worsens the prognosis of cryptococcal meningitis. In this review, we summarize the biological aspects of Cryptococcus and provide an update on the diagnosis and management of pulmonary cryptococcosis.
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Affiliation(s)
- Findra Setianingrum
- Division of Infection, Immunity and Respiratory Medicine, Faculty of Biology, Medicine and Health, University of Manchester, UK
- Parasitology Department, Universitas Indonesia, Jakarta, Indonesia
| | - Riina Rautemaa-Richardson
- Division of Infection, Immunity and Respiratory Medicine, Faculty of Biology, Medicine and Health, University of Manchester, UK
- Mycology Reference Centre Manchester, ECMM Centre of Excellence in Clinical and Laboratory Mycology and Clinical Studies, Wythenshawe Hospital, Manchester University NHS Foundation Trust, Manchester, UK
- Department of Infectious Diseases, Wythenshawe Hospital Manchester University NHS Foundation Trust, Manchester, UK
| | - David W Denning
- Division of Infection, Immunity and Respiratory Medicine, Faculty of Biology, Medicine and Health, University of Manchester, UK
- Department of Infectious Diseases, Wythenshawe Hospital Manchester University NHS Foundation Trust, Manchester, UK
- National Aspergillosis Centre, Wythenshawe Hospital, Manchester University NHS Foundation Trust, Manchester, UK
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McHugh KE, Gersey M, Rhoads DD, Procop GW, Zhang Y, Booth CN, Sturgis CD. Sensitivity of Cerebrospinal Fluid Cytology for the Diagnosis of Cryptococcal Infections: A 21-Year Single-Institution Retrospective Review. Am J Clin Pathol 2019; 151:198-204. [PMID: 30321269 DOI: 10.1093/ajcp/aqy133] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Objectives Cryptococcal meningoencephalitis is the most common fungal infection of the central nervous system diagnosed by cerebrospinal fluid cytology (CSF) studies. Existing literature suggests that routine CSF cytomorphologic evaluations are exquisitely specific; however, less is known about their sensitivity. Methods An electronic record review of the cytopathology and microbiology files was conducted for the 21-year interval from January 1, 1995, through December 31, 2015. Results In 21 years, 12,584 CSF samples were processed in the laboratory. Of these, 24 (0.2%) were reported positive for cryptococcal organisms by light microscopy, and 129 CSF fungal cultures were positive for Cryptococcus species. All cotested specimens with positive cytology results were positive on culture (15 specimens, 100% specificity). Twenty-four samples with positive culture results were negative by CSF cytology (sensitivity 39%). Conclusions When culture is used as a gold standard, CSF cytology is 100% specific and 39% sensitive, with a positive predictive value of 100% and a negative predictive value of 99.8%.
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Affiliation(s)
- Kelsey E McHugh
- Department of Laboratory Medicine, Cleveland Clinic, Cleveland, OH
| | - Melanie Gersey
- Department of Laboratory Medicine, Cleveland Clinic, Cleveland, OH
| | - Daniel D Rhoads
- Department of Pathology, Case Western Reserve University, Cleveland, OH
- Department of Pathology, University Hospitals Cleveland Medical Center, Cleveland, OH
| | - Gary W Procop
- Department of Laboratory Medicine, Cleveland Clinic, Cleveland, OH
| | - Yaxia Zhang
- Department of Pathology, Hospital for Special Surgery, New York, NY
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Zhu L, Maruvada R, Sapirstein A, Peters-Golden M, Kim KS. Cysteinyl leukotrienes as novel host factors facilitating Cryptococcus neoformans penetration into the brain. Cell Microbiol 2016; 19. [PMID: 27573789 DOI: 10.1111/cmi.12661] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 07/27/2016] [Accepted: 08/05/2016] [Indexed: 01/07/2023]
Abstract
Cryptococcus neoformas infection of the central nervous system (CNS) continues to be an important cause of mortality and morbidity, and a major contributing factor is our incomplete knowledge of the pathogenesis of this disease. Here, we provide the first direct evidence that C. neoformans exploits host cysteinyl leukotrienes (LTs), formed via LT biosynthetic pathways involving cytosolic phospholipase A2 α (cPLA2 α) and 5-lipoxygenase (5-LO) and acting via cysteinyl leukotriene type 1 receptor (CysLT1), for penetration of the blood-brain barrier. Gene deletion of cPLA2 α and 5-LO and pharmacological inhibition of cPLA2 α, 5-LO and CysLT1 were effective in preventing C. neoformans penetration of the blood-brain barrier in vitro and in vivo. A CysLT1 antagonist enhanced the efficacy of an anti-fungal agent in therapy of C. neoformans CNS infection in mice. These findings demonstrate that host cysteinyl LTs, dependent on the actions of cPLA2 α and 5-LO, promote C. neoformans penetration of the blood-brain barrier and represent novel targets for elucidating the pathogenesis and therapeutic development of C. neoformans CNS infection.
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Affiliation(s)
- Longkun Zhu
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Cell Biology and Medical Genetics/Center for Cell and Developmental Biology, School of Basic Medical Sciences Fujian Medical University, Fuzhou, Fujian, China
| | - Ravi Maruvada
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Adam Sapirstein
- Department of Anesthesiology and Critical Care Medicine, Baltimore, MD, USA
| | - Marc Peters-Golden
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Kwang Sik Kim
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Diagnostic Challenges of Cryptococcus neoformans in an Immunocompetent Individual Masquerading as Chronic Hydrocephalus. Case Rep Neurol Med 2016; 2016:7381943. [PMID: 27525140 PMCID: PMC4971305 DOI: 10.1155/2016/7381943] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 05/24/2016] [Indexed: 12/03/2022] Open
Abstract
Cryptococcus neoformans can cause disseminated meningoencephalitis and evade immunosurveillance with expression of a major virulence factor, the polysaccharide capsule. Direct diagnostic assays often rely on the presence of the cryptococcal glucuronoxylomannan capsular antigen (CrAg) or visualization of the capsule. Strain specific phenotypic traits and environmental conditions influence differences in expression that can thereby compromise detection and timely diagnosis. Immunocompetent hosts may manifest clinical signs and symptoms indolently, often expanding the differential and delaying appropriate treatment and diagnosis. We describe a 63-year-old man who presented with a progressive four-year history of ambulatory dysfunction, headache, and communicating hydrocephalus. Serial lumbar punctures (LPs) revealed elevated protein (153–300 mg/dL), hypoglycorrhachia (19–47 mg/dL), lymphocytic pleocytosis (89–95% lymphocyte, WBC 67–303 mg/dL, and RBC 34–108 mg/dL), and normal opening pressure (13–16 cm H2O). Two different cerebrospinal fluid (CSF) CrAg assays were negative. A large volume CSF fungal culture grew unencapsulated C. neoformans. He was initiated on induction therapy with amphotericin B plus flucytosine and consolidation/maintenance therapy with flucytosine, but he died following discharge due to complications. Elevated levels of CSF Th1 cytokines and decreased IL6 may have affected the virulence and detection of the pathogen.
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Curbelo J, Galván JM, Aspa J. Actualización sobre Aspergillus, Pneumocystis y otras micosis pulmonares oportunistas. Arch Bronconeumol 2015; 51:647-53. [DOI: 10.1016/j.arbres.2015.02.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 02/19/2015] [Accepted: 02/20/2015] [Indexed: 01/15/2023]
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Chen YC, Chang TY, Liu JW, Chen FJ, Chien CC, Lee CH, Lu CH. Increasing trend of fluconazole-non-susceptible Cryptococcus neoformans in patients with invasive cryptococcosis: a 12-year longitudinal study. BMC Infect Dis 2015; 15:277. [PMID: 26194004 PMCID: PMC4509779 DOI: 10.1186/s12879-015-1023-8] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2014] [Accepted: 07/13/2015] [Indexed: 12/23/2022] Open
Abstract
Background This study aimed to investigate the rate of fluconazole-non-susceptible Cryptococcus neoformans in Southern Taiwan for the period 2001–2012 and analyze the risk factors for acquiring it among patients with invasive cryptococcosis. Methods All enrolled strains were isolated from blood or cerebrospinal fluid samples of the included patients. If a patient had multiple positive results for C. neoformans, only the first instance was enrolled. Susceptibility testing was performed using the Clinical and Laboratory Standards Institutes M27-A3 broth micro-dilution method. The MIC interpretative criteria for susceptibility to fluconazole were ≤8 μg/ml. A total of 89 patients were included. Patients (n = 59) infected by fluconazole-susceptible strains were compared with those (n = 30) infected by non-susceptible strains. The patients’ demographic and clinical characteristics were analyzed. Results The rate of fluconazole-non-susceptible C. neoformans in the study period significantly increased over time (p < 0.001). The C. neoformans isolated in 2011–2012 (odds ratio: 10.68; 95 % confidence interval: 2.87-39.74; p < 0.001) was an independent predictive factor for the acquisition of fluconazole-non-susceptible C. neoformans. Conclusions The rate of fluconazole-non-susceptible C. neoformans has significantly increased recently. Continuous and large-scale anti-fungal susceptibility tests for C. neoformans are warranted to confirm this trend.
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Affiliation(s)
- Yi-Chun Chen
- Division of Infectious Diseases, Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan.
| | - Tzu-Yao Chang
- Division of Infectious Diseases, Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan.
| | - Jien-Wei Liu
- Division of Infectious Diseases, Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan. .,Chang Gung University College of Medicine, 123 Ta-Pei Road, Niao-Sung District, Kaohsiung City, 833, Taiwan.
| | - Fang-Ju Chen
- Division of Infectious Diseases, Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan.
| | - Chun-Chih Chien
- Department of Laboratory Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan.
| | - Chen-Hsiang Lee
- Division of Infectious Diseases, Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan. .,Chang Gung University College of Medicine, 123 Ta-Pei Road, Niao-Sung District, Kaohsiung City, 833, Taiwan.
| | - Cheng-Hsien Lu
- Chang Gung University College of Medicine, 123 Ta-Pei Road, Niao-Sung District, Kaohsiung City, 833, Taiwan. .,Department of Neurology, Kaohsiung Chang Gung Memorial Hospital, 123 Ta-Pei Road, Niao-Sung District, Kaohsiung City, 833, Taiwan. .,Department of Biological Science, National Sun Yat-Sen University, Kaohsiung, Taiwan.
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Abstract
UNLABELLED Cryptococcosis is an opportunistic infection due to the ubiquitous yeast Cryptococcus neoformans. This yeast interacts closely with innate immune cells, leading to various fates, including fungal persistence within cells, making possible the dissemination of the yeast cells with monocytes via a Trojan horse strategy. In humans, the natural history of the infection begins with primoinfection during childhood, which is followed by dormancy and, in some individuals, reactivation upon immunosuppression. To address the question of dormancy, we studied C. neoformans infection at the macrophage level (in vitro H99-macrophage interaction) and at the organ level in a murine model of cryptococcosis. We analyzed the diversity of yeast adaptation to the host by characterizing several C. neoformans populations with new assays based on flow cytometry (quantitative flow cytometry, multispectral imaging flow cytometry, sorting), microscopy (dynamic imaging), and gene expression analysis. On the basis of parameters of multiplication and stress response, various populations of yeast cells were observed over time in vivo and in vitro. Cell sorting allowed the identification of a subpopulation that was less prone to grow under standard conditions than the other populations, with growth enhanced by the addition of serum. Gene expression analysis revealed that this population had specific metabolic characteristics that could reflect dormancy. Our data suggest that dormant yeast cells could exist in vitro and in vivo. C. neoformans exhibits a huge plasticity and adaptation to hosts that deserves further study. In vitro generation of dormant cells is now the main challenge to overcome the limited number of yeast cells recovered in our models. IMPORTANCE Cryptococcus neoformans is a sugar-coated unicellular fungus that interacts closely with various cells and organisms, including amoebas, nematodes, and immune cells of mammals. This yeast is able to proliferate and survive in the intracellular environment. C. neoformans causes cryptococcosis, and yeast dormancy in humans has been suggested on the basis of epidemiological evidence obtained years ago. By studying an in vitro model of yeast-macrophage interaction and murine models of cryptococcosis, we observed that yeast cells evolve in heterogeneous populations during infection on the basis of global metabolic activity. We compared the growth ability and gene expression of yeast cells belonging to various populations in those two models. We eventually found a population of yeast cells with low metabolism that fit some of the criteria for dormant cells. This paves the way for further characterization of dormancy in C. neoformans.
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Mischnik A, Stockklausner J, Hohneder N, Jensen HE, Zimmermann S, Reuss DE, Rickerts V, Tintelnot K, Stockklausner C. First case of disseminated cryptococcosis in aGorilla gorilla. Mycoses 2014; 57:664-71. [DOI: 10.1111/myc.12215] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 05/21/2014] [Accepted: 06/01/2014] [Indexed: 02/02/2023]
Affiliation(s)
- Alexander Mischnik
- Department of Infectious Diseases, Medical Microbiology and Hygiene; Heidelberg University Hospital; Heidelberg Germany
| | | | | | - Henrik E. Jensen
- Department of Veterinary Disease Biology; Faculty of Life Sciences; University of Copenhagen; Copenhagen Denmark
| | - Stefan Zimmermann
- Department of Infectious Diseases, Medical Microbiology and Hygiene; Heidelberg University Hospital; Heidelberg Germany
| | - David E. Reuss
- Department of Neuropathology; Institute of Pathology; Heidelberg University Hospital and German Cancer Consortium (DKTK); Clinical Cooperation Unit Neuropathology; German Cancer Research Center (DKFZ); Heidelberg Germany
| | | | | | - Clemens Stockklausner
- Department of Pediatric Oncology and Hematology; Heidelberg University Hospital; Heidelberg Germany
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Stone NRH, Bicanic T. Therapy of AIDS-Related Cryptococcal Meningitis. CURRENT TREATMENT OPTIONS IN INFECTIOUS DISEASES 2014. [DOI: 10.1007/s40506-014-0018-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Srikanta D, Santiago-Tirado FH, Doering TL. Cryptococcus neoformans: historical curiosity to modern pathogen. Yeast 2014; 31:47-60. [PMID: 24375706 PMCID: PMC3938112 DOI: 10.1002/yea.2997] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 12/06/2013] [Accepted: 12/10/2013] [Indexed: 12/22/2022] Open
Abstract
The importance of the Basidiomycete Cryptococcus neoformans to human health has stimulated its development as an experimental model for both basic physiology and pathogenesis. We briefly review the history of this fascinating and versatile fungus, some notable aspects of its biology that contribute to virulence, and current tools available for its study.
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Affiliation(s)
- Deepa. Srikanta
- Department of Molecular Microbiology, Washington University School of Medicine
| | | | - Tamara L. Doering
- Department of Molecular Microbiology, Washington University School of Medicine
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Abstract
Urease in Cryptococcus neoformans plays an important role in fungal dissemination to the brain and causing meningoencephalitis. Although urea is not required for synthesis of apourease encoded by URE1, the available nitrogen source affected the expression of URE1 as well as the level of the enzyme activity. Activation of the apoenzyme requires three accessory proteins, Ure4, Ure6, and Ure7, which are homologs of the bacterial urease accessory proteins UreD, UreF, and UreG, respectively. A yeast two-hybrid assay showed positive interaction of Ure1 with the three accessory proteins encoded by URE4, URE6, and URE7. Metalloproteomic analysis of cryptococcal lysates using inductively coupled plasma mass spectrometry (ICP-MS) and a biochemical assay of urease activity showed that, as in many other organisms, urease is a metallocentric enzyme that requires nickel transported by Nic1 for its catalytic activity. The Ure7 accessory protein (bacterial UreG homolog) binds nickel likely via its conserved histidine-rich domain and appears to be responsible for the incorporation of Ni2+ into the apourease. Although the cryptococcal genome lacks the bacterial UreE homolog, Ure7 appears to combine the functions of bacterial UreE and UreG, thus making this pathogen more similar to that seen with the plant system. Brain invasion by the ure1, ure7, and nic1 mutant strains that lack urease activity was significantly less effective in a mouse model. This indicated that an activated urease and not the Ure1 protein was responsible for enhancement of brain invasion and that the factors required for urease activation in C. neoformans resemble those of plants more than those of bacteria. Cryptococcus neoformans is the major fungal agent of meningoencephalitis in humans. Although urease is an important factor for cryptococcal brain invasion, the enzyme activation system has not been studied. We show that urease is a nickel-requiring enzyme whose activity level is influenced by the type of available nitrogen source. C. neoformans contains all the bacterial urease accessory protein homologs and nickel transporters except UreE, a nickel chaperone. Cryptococcal Ure7 (a homolog of UreG) apparently functions as both the bacterial UreG and UreE in activating the Ure1 apoenzyme. The cryptococcal urease accessory proteins Ure4, Ure6, and Ure7 interacted with Ure1 in a yeast two-hybrid assay, and deletion of any one of these not only inactivated the enzyme but also reduced the efficacy of brain invasion. This is the first study showing a holistic picture of urease in fungi, clarifying that urease activity, and not Ure1 protein, contributes to pathogenesis in C. neoformans
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Sabiiti W, May RC. Capsule independent uptake of the fungal pathogen Cryptococcus neoformans into brain microvascular endothelial cells. PLoS One 2012; 7:e35455. [PMID: 22530025 PMCID: PMC3328471 DOI: 10.1371/journal.pone.0035455] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Accepted: 03/17/2012] [Indexed: 01/11/2023] Open
Abstract
Cryptococcosis is a life-threatening fungal disease with a high rate of mortality among HIV/AIDS patients across the world. The ability to penetrate the blood-brain barrier (BBB) is central to the pathogenesis of cryptococcosis, but the way in which this occurs remains unclear. Here we use both mouse and human brain derived endothelial cells (bEnd3 and hCMEC/D3) to accurately quantify fungal uptake and survival within brain endothelial cells. Our data indicate that the adherence and internalisation of cryptococci by brain microvascular endothelial cells is an infrequent event involving small numbers of cryptococcal yeast cells. Interestingly, this process requires neither active signalling from the fungus nor the presence of the fungal capsule. Thus entry into brain microvascular endothelial cells is most likely a passive event that occurs following ‘trapping’ within capillary beds of the BBB.
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Affiliation(s)
- Wilber Sabiiti
- Institute of Microbiology & Infection, School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Robin C. May
- Institute of Microbiology & Infection, School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom
- * E-mail:
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Abstract
Fungal meningitis is a serious disease caused by a fungal infection of the central nervous system (CNS) mostly in individuals with immune system deficiencies. Fungal meningitis is often fatal without proper treatment, and the mortality rate remains unacceptably high even with antifungal drug interventions. Currently, cryptococcal meningitis is the most common fungal meningitis in HIV-1/AIDS, and its disease mechanism has been extensively studied. The key steps for fungi to infect brain and cause meningitis after establishment of local infection are the dissemination of fungal cells to the bloodstream and invasion through the blood brain barrier to reach the CNS. In this review, we use cryptococcal CNS infection as an example to describe the current molecular understanding of fungal meningitis, including the establishment of the infection, dissemination, and brain invasion. Host and microbial factors that contribute to these infection steps are also discussed.
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Affiliation(s)
- Tong-Bao Liu
- The Public Health Research Institute, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark, NJ, USA
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Disseminated cryptococcal infection in patient with novel JAK3 mutation severe combined immunodeficiency, with resolution after stem cell transplantation. Pediatr Infect Dis J 2012; 31:204-6. [PMID: 22138680 DOI: 10.1097/inf.0b013e318239c3b3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Disseminated cryptococcal infection is the second most common cause of death after tuberculosis in acquired immune deficiency syndrome patients. Surprisingly, it has been reported only in few patients with primary immunodeficiency diseases. Herein, we report the clinical presentation and outcome of a 23-month-old boy with novel JAK3 mutation severe combined immunodeficiency disease complicated by severe disseminated cryptococcal infection.
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Lessons from Cryptococcal Laccase: From Environmental Saprophyte to Pathogen. CURRENT FUNGAL INFECTION REPORTS 2011. [DOI: 10.1007/s12281-011-0069-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Srikanta D, Yang M, Williams M, Doering TL. A sensitive high-throughput assay for evaluating host-pathogen interactions in Cryptococcus neoformans infection. PLoS One 2011; 6:e22773. [PMID: 21829509 PMCID: PMC3145667 DOI: 10.1371/journal.pone.0022773] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Accepted: 06/29/2011] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Cryptococcus neoformans causes serious disease in immunocompromised individuals, leading to over 600,000 deaths per year worldwide. Part of this impact is due to the organism's ability to thwart what should be the mammalian hosts' first line of defense against cryptococcal infection: internalization by macrophages. Even when C. neoformans is engulfed by host phagocytes, it can survive and replicate within them rather than being destroyed; this ability is central in cryptococcal virulence. It is therefore critical to elucidate the interactions of this facultative intracellular pathogen with phagocytic cells of its mammalian host. METHODOLOGY/PRINCIPAL FINDINGS To accurately assess initial interactions between human phagocytic cells and fungi, we have developed a method using high-throughput microscopy to efficiently distinguish adherent and engulfed cryptococci and quantitate each population. This method offers significant advantages over currently available means of assaying host-fungal cell interactions, and remains statistically robust when implemented in an automated fashion appropriate for screening. It was used to demonstrate the sensitivity of human phagocytes to subtle changes in the cryptococcal capsule, a major virulence factor of this pathogen. CONCLUSIONS/SIGNIFICANCE Our high-throughput method for characterizing interactions between C. neoformans and mammalian phagocytic cells offers a powerful tool for elucidating the relationship between these cell types during pathogenesis. This approach will be useful for screens of this organism and has potentially broad applications for investigating host-pathogen interactions.
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Affiliation(s)
- Deepa Srikanta
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Meng Yang
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Matthew Williams
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Tamara L. Doering
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
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Florio AR, Ferrari S, De Carolis E, Torelli R, Fadda G, Sanguinetti M, Sanglard D, Posteraro B. Genome-wide expression profiling of the response to short-term exposure to fluconazole in Cryptococcus neoformans serotype A. BMC Microbiol 2011; 11:97. [PMID: 21569340 PMCID: PMC3119188 DOI: 10.1186/1471-2180-11-97] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Accepted: 05/11/2011] [Indexed: 12/31/2022] Open
Abstract
Background Fluconazole (FLC), a triazole antifungal drug, is widely used for the maintenance therapy of cryptococcal meningoencephalitis, the most common opportunistic infection in AIDS patients. In this study, we examined changes in the gene expression profile of the C. neoformans reference strain H99 (serotype A) following FLC treatment in order to investigate the adaptive cellular responses to drug stress. Results Simultaneous analysis of over 6823 transcripts revealed that 476 genes were responsive to FLC. As expected up-regulation of genes involved in ergosterol biosynthesis was observed, including the azole target gene ERG11 and ERG13, ERG1, ERG7, ERG25, ERG2, ERG3 and ERG5. In addition, SRE1 which is a gene encoding a well-known regulator of sterol homeostasis in C. neoformans was up-regulated. Several other genes such as those involved in a variety of important cellular processes (i.e. lipid and fatty acid metabolism, cell wall maintenance, stress and virulence) were found to be up-regulated in response to FLC treatment. Conversely, expression of AFR1, the major transporter of azoles in C. neoformans, was not regulated by FLC. Conclusions Short-term exposure of C. neoformans to FLC resulted in a complex altered gene expression profile. Some of the observed changes could represent specific adaptive responses to the antifungal agent in this pathogenic yeast.
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Affiliation(s)
- Ada Rita Florio
- Istituto di Microbiologia, Università Cattolica del Sacro Cuore, Largo F. Vito 1, 00168 Rome, Italy
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Whittington A, Wang P. The RGS protein Crg2 is required for establishment and progression of murine pulmonary cryptococcosis. Med Mycol 2010; 49:263-75. [PMID: 20818923 DOI: 10.3109/13693786.2010.512618] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Cryptococcal regulators of G protein signaling (CRG) are important for growth, differentiation, and virulence of Cryptococcus neoformans. Disruption of CRG2 resulted in dysregulated cAMP signaling and attenuated virulence, whereas disruption of CRG1 increased pheromone responses and enhanced virulence in the archetypal H99 strain. In tests with newly constructed near congenic mutants, a distinction between crg2Δ and crg1Δ gene expression was not apparent during macrophage interaction. Intranasal inoculation indicated that crg2Δ, crg1Δ, and wild-type strains reached the lungs within 0.5 hours of infection. However, CFUs were significantly decreased for crg2Δ at 2, 7, and 14 days post-infection. In contrast, crg1Δ proliferated to the same extent as the wild type (WT). Lung edema was not apparent in mice infected with crg2Δ 0.5 hours post-infection, which showed little cellular infiltrate in comparison to WT. Alveolar septal thickening was most evident in mice infected with crg1Δ, while mice infected with WT exhibited decreased septal thickening at later time points. Consistent with these observations, crg2Δ was less efficient in the elicitation of Th2 immune responses in a multiplex cytokine assay. Our results suggest that Crg2 is critical for establishment of early pulmonary infection and for persistence of infection, Crg1 regulates virulence in a strain-specific manner, and crg2Δ, crg1Δ and WT can all be distinguished on the basis of host tissue responses.
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Affiliation(s)
- Amy Whittington
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
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Vu K, Gelli A. Astemizole and an analogue promote fungicidal activity of fluconazole againstCryptococcus neoformansvar.grubiiandCryptococcus gattii. Med Mycol 2010. [DOI: 10.3109/13693780903081968] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Kim MS, Kim SY, Yoon JK, Lee YW, Bahn YS. An efficient gene-disruption method in Cryptococcus neoformans by double-joint PCR with NAT-split markers. Biochem Biophys Res Commun 2009; 390:983-8. [PMID: 19852932 DOI: 10.1016/j.bbrc.2009.10.089] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2009] [Accepted: 10/16/2009] [Indexed: 10/20/2022]
Abstract
Targeted gene disruption via biolistic transformation and homologous recombination is a method widely used to identify and investigate the function of genes in Cryptococcus neoformans that causes fatal fungal meningitis if not timely treated. Currently, most laboratories employ the overlap-PCR method to generate a gene-disruption cassette with dominant selectable markers, such as nourseothricin acetyltransferase (NAT). However, the conventional overlap-PCR method is often found to be inefficient because of the presence of multiple templates and of the long length of the final overlap-PCR products. In this report, we suggested an efficient gene-disruption method for C. neoformans, termed a double-joint PCR with NAT-split markers. Here we demonstrated that the gene-disruption cassette generated using double-joint PCR with NAT-split markers can be used successfully for targeted C. neoformans gene disruption with the advantages of providing a more convenient construction of gene-disruption cassettes and high targeted-integration frequency.
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Affiliation(s)
- Min Su Kim
- Department of Biotechnology, Center for Fungal Pathogenesis, Yonsei University, Seoul 120-749, Republic of Korea
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Eisenman HC, Frases S, Nicola AM, Rodrigues ML, Casadevall A. Vesicle-associated melanization in Cryptococcus neoformans. MICROBIOLOGY-SGM 2009; 155:3860-3867. [PMID: 19729402 DOI: 10.1099/mic.0.032854-0] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Recently, several pathogenic fungi were shown to produce extracellular vesicles that contain various components associated with virulence. In the human pathogenic fungus Cryptococcus neoformans, these components included laccase, an enzyme that catalyses melanin synthesis. Spherical melanin granules have been observed in the cell wall of C. neoformans. Given that melanin granules have dimensions that are comparable to those of extracellular vesicles, and that metazoan organisms produce melanin in vesicular structures known as melanosomes, we investigated the role of vesicles in cryptococcal melanization. Extracellular vesicles melanized when incubated with the melanin precursor L-3,4-dihydroxyphenylalanine (L-DOPA). The kinetics of substrate incorporation into cells and vesicles was analysed using radiolabelled L-DOPA. The results indicated that substrate incorporation was different for cells and isolated vesicles. Acid-generated melanin ghosts stained with lipophilic dyes, implying the presence of associated lipid. A model for C. neoformans melanization is proposed that accounts for these observations and provides a mechanism for the assembly of melanin into relatively uniform spherical particles stacked in an orderly arrangement in the cell wall.
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Affiliation(s)
- Helene C Eisenman
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Susana Frases
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - André M Nicola
- Departamento de Biologia Celular, Universidade de Brasília, Brazil.,Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Marcio L Rodrigues
- Laboratório de Estudos Integrados em Bioquímica Microbiana, Instituto de Microbiologia Professor Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-590, Brazil
| | - Arturo Casadevall
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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The capsule of the fungal pathogen Cryptococcus neoformans. ADVANCES IN APPLIED MICROBIOLOGY 2009; 68:133-216. [PMID: 19426855 DOI: 10.1016/s0065-2164(09)01204-0] [Citation(s) in RCA: 321] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The capsule of the fungal pathogen Cryptococcus neoformans has been studied extensively in recent decades and a large body of information is now available to the scientific community. Well-known aspects of the capsule include its structure, antigenic properties and its function as a virulence factor. The capsule is composed primarily of two polysaccharides, glucuronoxylomannan (GXM) and galactoxylomannan (GalXM), in addition to a smaller proportion of mannoproteins (MPs). Most of the studies on the composition of the capsule have focused on GXM, which comprises more than 90% of the capsule's polysaccharide mass. It is GalXM, however, that is of particular scientific interest because of its immunological properties. The molecular structure of these polysaccharides is very complex and has not yet been fully elucidated. Both GXM and GalXM are high molecular mass polymers with the mass of GXM equaling roughly 10 times that of GalXM. Recent findings suggest, however, that the actual molecular weight might be different to what it has traditionally been thought to be. In addition to their structural roles in the polysaccharide capsule, these molecules have been associated with many deleterious effects on the immune response. Capsular components are therefore considered key virulence determinants in C. neoformans, which has motivated their use in vaccines and made them targets for monoclonal antibody treatments. In this review, we will provide an update on the current knowledge of the C. neoformans capsule, covering aspects related to its structure, synthesis and particularly, its role as a virulence factor.
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Charlier C, Nielsen K, Daou S, Brigitte M, Chretien F, Dromer F. Evidence of a role for monocytes in dissemination and brain invasion by Cryptococcus neoformans. Infect Immun 2009; 77:120-7. [PMID: 18936186 PMCID: PMC2612285 DOI: 10.1128/iai.01065-08] [Citation(s) in RCA: 275] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2008] [Revised: 09/11/2008] [Accepted: 10/08/2008] [Indexed: 01/01/2023] Open
Abstract
The pathogenesis of cryptococcosis, including the events leading to the production of meningoencephalitis, is still largely unknown. Evidence of a transcellular passage of Cryptococcus neoformans across the blood-brain barrier (BBB) and subsequent BBB disruption exists, but the paracellular passage of free yeasts and the role of monocytes in yeast dissemination and brain invasion (Trojan horse method) remain uncertain. We used our model of disseminated cryptococcosis, in which crossing of the BBB starts 6 h after intravenous inoculation, to study paracellular passage of the BBB. We prepared bone marrow-derived monocytes (BMDM) infected in vitro with C. neoformans (BMDM yeasts) and free yeasts and measured fungal loads in tissues. (i) Spleen and lung CFU were >2-fold higher in mice treated with BMDM yeasts than in those treated with free yeasts for 1 and 24 h (P < 0.05), while brain CFU were increased (3.9 times) only at 24 h (P < 0.05). (ii) By comparing the kinetics of brain invasion in naïve mice and in mice with preestablished cryptococcosis, we found that CFU were lower in the latter case, except at 6 h, when CFU from mice inoculated with BMDM yeasts were comparable to those measured in naïve mice and 2.5-fold higher than those in mice with preestablished cryptococcosis who were inoculated with free yeasts. (iii) Late phagocyte depletion obtained by clodronate injection reduced disease severity and lowered the fungal burden by 40% in all organs studied. These results provide evidence for Trojan horse crossing of the BBB by C. neoformans, together with mechanisms involving free yeasts, and overall for a role of phagocytes in fungal dissemination.
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Affiliation(s)
- Caroline Charlier
- Unité de Mycologie Moléculaire, CNRS URA3012, Institut Pasteur, 25 rue du Dr. Roux, 75724 Paris Cedex 15, France
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Jong A, Wu CH, Prasadarao NV, Kwon-Chung KJ, Chang YC, Ouyang Y, Shackleford GM, Huang SH. Invasion of Cryptococcus neoformans into human brain microvascular endothelial cells requires protein kinase C-alpha activation. Cell Microbiol 2008; 10:1854-65. [PMID: 18489726 DOI: 10.1111/j.1462-5822.2008.01172.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Pathogenic fungus Cryptococcus neoformans has a predilection for the central nervous system causing devastating meningoencephalitis. Traversal of C. neoformans across the blood-brain barrier (BBB) is a crucial step in the pathogenesis of C. neoformans. Our previous studies have shown that the CPS1 gene is required for C. neoformans adherence to the surface protein CD44 of human brain microvascular endothelial cells (HBMEC), which constitute the BBB. In this report, we demonstrated that C. neoformans invasion of HBMEC was blocked in the presence of G109203X, a protein kinase C (PKC) inhibitor, and by overexpression of a dominant-negative form of PKCalpha in HBMEC. During C. neoformans infection, phosphorylation of PKCalpha was induced and the PKC enzymatic activity was detected in the HBMEC membrane fraction. Our results suggested that the PKCalpha isoform might play a crucial role during C. neoformans invasion. Immunofluorescence microscopic images showed that induced phospho-PKCalpha colocalized with beta-actin on the membrane of HBMEC. In addition, cytochalasin D (an F-filament-disrupting agent) inhibited fungus invasion into HBMEC in a dose-dependent manner. Furthermore, blockage of PKCalpha function attenuated actin filament activity during C. neoformans invasion. These results suggest a significant role of PKCalpha and downstream actin filament activity during the fungal invasion into HBMEC.
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Affiliation(s)
- Ambrose Jong
- Division of Hematology-Oncology, Children's Hospital Los Angeles, Los Angeles, CA 90027, USA.
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Panepinto J, Komperda K, Frases S, Park YD, Djordjevic JT, Casadevall A, Williamson PR. Sec6-dependent sorting of fungal extracellular exosomes and laccase of Cryptococcus neoformans. Mol Microbiol 2008; 71:1165-76. [PMID: 19210702 DOI: 10.1111/j.1365-2958.2008.06588.x] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The cell wall of pathogenic fungi such as Cryptococcus neoformans, provides a formidable barrier to secrete virulence factors that produce host cell damage. To study secretion of virulence factors to the cell periphery, sec6 RNAi mutant strains of C. neoformans were tested for virulence factor expression. The studies reported here show that SEC6 RNAi mutant strains were defective in a number of virulence factors including laccase, urease as well as soluble polysaccharide and demonstrated attenuated virulence in mice. Further analysis by transmission electron microscopy detected the production of abundant extracellular exosomes in wild-type strains containing empty plasmid, but a complete absence in the iSEC6 strain. In addition, a green fluorescent protein-laccase fusion protein demonstrated aberrant localization within cytoplasmic vesicles in iSEC6 strains. In contrast, iSEC6 strains retained normal growth at 37 degrees C, as well as substantially normal capsule formation, phospholipase activity and total secreted protein. These results provide the first molecular evidence for the existence of fungal exosomes and associate these vesicles with the virulence of C. neoformans.
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Affiliation(s)
- John Panepinto
- Section of Infectious Diseases, Department of Medicine, University of Illinois at Chicago College of Medicine, Chicago, IL, USA
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