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Sanchez Ramirez L, Dragotakes Q, Casadevall A. A food color-based colorimetric assay for Cryptococcus neoformans laccase activity. Microbiol Spectr 2024:e0044224. [PMID: 38869282 DOI: 10.1128/spectrum.00442-24] [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: 04/05/2024] [Accepted: 05/09/2024] [Indexed: 06/14/2024] Open
Abstract
Cryptococcus neoformans is a fungal pathogen that causes cryptococcosis primarily in immunocompromised patients, such as those with HIV/AIDS. One survival mechanism of C. neoformans during infection is melanin production, which catalyzed by laccase and protects fungal cells against immune attack. Hence, the comparative assessment of laccase activity is useful for characterizing cryptococcal strains. We serendipitously observed that culturing C. neoformans with food coloring resulted in degradation of some dyes with phenolic structures. Consequently, we investigated the color changes for the food dyes metabolized by C. neoformans laccase and by using this effect explored the development of a colorimetric assay to measure laccase activity. We developed several versions of a food dye-based colorimetric laccase assay that can be used to compare the relative laccase activities between different C. neoformans strains. We found that phenolic color degradation was glucose-dependent, which may reflect changes in the reduction properties of the media. Our food color-based colorimetric assay has several advantages, including lower cost, irreversibility, and not requiring constant monitoring , over the commonly used 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay for determining laccase activity. This method has potential applications to bioremediation of water pollutants in addition to its use in determining laccase virulence factor expression.IMPORTANCECryptococcus neoformans is present in the environment, and while infection is common, disease occurs mostly in immunocompromised individuals. C. neoformans infection in the lungs results in symptoms like pneumonia, and consequently, cryptococcal meningitis occurs if the fungal infection spreads to the brain. The laccase enzyme catalyzes the melanization reaction that serves as a virulence factor for C. neoformans. Developing a simple and less costly assay to determine the laccase activity in C. neoformans strains can be useful for a variety of procedures ranging from studying the relative virulence of cryptococci to environmental pollution studies.
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Affiliation(s)
- Lia Sanchez Ramirez
- Department of Molecular and Cell Biology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Quigly Dragotakes
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, Maryland, USA
| | - Arturo Casadevall
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, Maryland, USA
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Okurut S, Boulware DR, Manabe YC, Tugume L, Skipper CP, Ssebambulidde K, Rhein J, Musubire AK, Akampurira A, Okafor E, Olobo JO, Janoff EN, Meya DB. Impact of Cerebrospinal Fluid Leukocyte Infiltration and Neuroimmmune Mediators on Survival with HIV-Associated Cryptococcal Meningitis. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.05.29.24308130. [PMID: 38854002 PMCID: PMC11160828 DOI: 10.1101/2024.05.29.24308130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Introduction Cryptococcal meningitis remains a prominent cause of death in persons with advanced HIV disease. CSF leukocyte infiltration predicts survival at 18 weeks; however, how CSF immune response relates to CSF leukocyte infiltration is unknown. Methods We enrolled 401 adults with HIV-associated cryptococcal meningitis in Uganda who received amphotericin and fluconazole induction therapy. We assessed the association of CSF leukocytes, chemokine, and cytokine responses with 18-week survival. Results Participants with CSF leukocytes ≥50/μL, had higher probability 68% (52/77) of 18-week survival compared with 52% (151/292) 18-week survival in those with ≤50 cells/μL (Hazard Ratio=1.63, 95% confidence intervals 1.14-2.23; p=0.008). Survival was also associated with higher expression of T helper (Th)-1, Th17 cytokines, and immune regulatory elements. CSF levels of Programmed Death-1 Ligand, CXCL10, and Interleukin (IL)-2 independently predicted survival. In multivariate analysis, CSF leukocytes were inversely associated with CSF fungal burden and positively associated with CSF protein, interferon-gamma (IFN-γ), IL-17A, tumor necrosis factor (TNF)-α, and peripheral blood CD4+ and CD8+ T cells expression. Conclusion 18-week survival after diagnosis of cryptococcal meningitis was associated with higher CSF leukocytes at baseline with greater T helper 1 (IFN-γ, IL-2 and TNF-α cytokines), T helper 17 (IL-17A cytokine) and CXCR3+ T cell (CXCL10 chemokine) responses. These results highlight the interdependent contribution of soluble and cellular immune responses in predicting survival with HIV-associated cryptococcal meningitis.
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Affiliation(s)
- Samuel Okurut
- Research Department, Infectious Diseases Institute, Makerere University, Kampala, Uganda
- Department of Medical Microbiology, School of Biomedical Sciences, College of Health Sciences, Makerere University, Kampala, Uganda
| | - David R. Boulware
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Yukari C. Manabe
- Research Department, Infectious Diseases Institute, Makerere University, Kampala, Uganda
- Division of Infectious Diseases, Department of Medicine, John Hopkins University School of Medicine, Baltimore, Maryland, MD, USA
| | - Lillian Tugume
- Research Department, Infectious Diseases Institute, Makerere University, Kampala, Uganda
| | - Caleb P. Skipper
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Kenneth Ssebambulidde
- Research Department, Infectious Diseases Institute, Makerere University, Kampala, Uganda
| | - Joshua Rhein
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Abdu K. Musubire
- Research Department, Infectious Diseases Institute, Makerere University, Kampala, Uganda
| | - Andrew Akampurira
- Research Department, Infectious Diseases Institute, Makerere University, Kampala, Uganda
- Department of Medical Microbiology, School of Biomedical Sciences, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Elizabeth Okafor
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Joseph O. Olobo
- Department of Immunology and Molecular Biology, School of Biomedical Sciences, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Edward N. Janoff
- Mucosal and Vaccine Research Program Colorado, Department of Medicine, Division of Infectious Diseases, University of Colorado Denver, Aurora, Colorado, CO. USA
- Rocky Mountain Regional Veterans Affairs Medical Center, Aurora CO, USA
| | - David B. Meya
- Research Department, Infectious Diseases Institute, Makerere University, Kampala, Uganda
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, USA
- Department of Medicine, School of Medicine, College of Health Sciences, Makerere University, Kampala, Uganda
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Hansakon A, Angkasekwinai P. Murine Models of Cryptococcus Infection. Curr Protoc 2024; 4:e1001. [PMID: 38456766 DOI: 10.1002/cpz1.1001] [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: 03/09/2024]
Abstract
Cryptococcus is recognized as one of the emerging fungal pathogens that have major impact on diverse populations worldwide. Because of the high mortality rate and limited antifungal therapy options, there is an urgent need to understand the impact of dynamic processes between fungal pathogens and hosts that influence cryptococcal pathogenesis and disease outcomes. With known common limitations in human studies, experimental murine cryptococcosis models that can recapitulate human disease provide a valuable tool for studying fungal virulence and the host interaction, leading to development of better treatment strategies. Infection with Cryptococcus in mice via intranasal inhalation is mostly used because it is noninvasive and considered to be the most common mode of infection, strongly correlating with cryptococcal disease in humans. The protocols described in this article provide the procedures of establishing a murine model of Cryptococcus infection by intranasal inhalation and assessing the host immune response and disease progression during Cryptococcus infection. © 2024 Wiley Periodicals LLC. Basic Protocol 1: Murine model of pulmonary cryptococcal infection via intranasal inhalation Basic Protocol 2: Assessment of the pulmonary immune response during Cryptococcus infection Support Protocol: Evaluation of pulmonary gene expression by real-time PCR Basic Protocol 3: Enumeration of survival rate and organ fungal burden.
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Affiliation(s)
- Adithap Hansakon
- Chulabhorn International College of Medicine, Thammasat University, Pathum Thani, Thailand
| | - Pornpimon Angkasekwinai
- Department of Medical Technology, Faculty of Allied Health Sciences, Thammasat University, Pathum Thani, Thailand
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Yang C, Shen W, Wang L, Zang X, Huang Y, Deng H, Zhou Y, Xie M, Xue X, Shen D. Cryptococcus gattii strains with a high phagocytosis phenotype by macrophages display high pathogenicity at the early stage of infection in vivo. Acta Biochim Biophys Sin (Shanghai) 2024; 56:291-303. [PMID: 37885429 PMCID: PMC10984874 DOI: 10.3724/abbs.2023250] [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: 08/15/2023] [Accepted: 10/09/2023] [Indexed: 10/28/2023] Open
Abstract
Cryptococcus gattii (Cg) is a facultative intracellular pathogen that can replicate and disseminate in mammalian macrophages, causing life-threatening cryptococcosis in both immunocompetent and immunocompromised individuals. Cryptococcus-macrophage interactions are crucial for cryptococcosis prognosis. However, the relationship between Cg pathogenicity and phagocytosis by macrophages has not yet been investigated in depth. In this study, a series of in vitro and in vivo experiments were conducted to investigate the interaction between macrophages and Cg. Flow cytometry was used to detect the phagocytic phenotypes of the Cg strains within macrophages. Scanning electron microscopy, transmission electron microscopy, and immunofluorescence were used to observe phagocytosis and proliferation, respectively. Survival and lung fungal burden tests were also performed. Our results show that Cg cells display different phagocytosis phenotypes, which are independent of the molecular type. Within macrophages, the high phagocytosis phenotype (HP) strains obtain higher intracellular proliferation than the low phagocytosis phenotype (LP) strains. At the early stage of infection in vivo, HP-inducing permissive granulomas within the lungs seldom limit the dissemination of cryptococci. In addition, HP strains could inhibit the formation of M1-type macrophages, proliferate intracellularly and disseminate extracellularly, and cause hypoxia induced by mucus and acidic polysaccharide accumulation in pulmonary alveoli much earlier than LP strains in vivo. Our work reveals that Cg displays diverse interactions with macrophages, which may enhance our understanding of the pathogenicity of this life-threatening pathogen.
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Affiliation(s)
- Chen Yang
- Department of Laboratory Medicinethe First Medical CentreChinese People’s Liberation Army (PLA) General HospitalBeijing100853China
| | - Wanjun Shen
- State Key Laboratory of Kidney DiseaseDepartment of NephrologyChinese People’s Liberation Army (PLA) General HospitalBeijing100853China
| | - Lifeng Wang
- Department of Laboratory Medicinethe First Medical CentreChinese People’s Liberation Army (PLA) General HospitalBeijing100853China
| | - Xuelei Zang
- Department of Respiratory and Critical CareBeijing Shijitan HospitalCapital Medical UniversityPeking University Ninth School of Clinical MedicineBeijing100089China
| | - Yemei Huang
- Department of Respiratory and Critical CareBeijing Shijitan HospitalCapital Medical UniversityPeking University Ninth School of Clinical MedicineBeijing100089China
| | - Hengyu Deng
- School of Clinical MedicineWeifang Medical UniversityWeifang261053China
| | - Yangyu Zhou
- Department of Respiratory and Critical CareBeijing Shijitan HospitalCapital Medical UniversityPeking University Ninth School of Clinical MedicineBeijing100089China
| | - Mei Xie
- of Respiratory and Critical CareChinese People’s Liberation Army (PLA) General HospitalBeijing100853China
| | - Xinying Xue
- Department of Respiratory and Critical CareBeijing Shijitan HospitalCapital Medical UniversityPeking University Ninth School of Clinical MedicineBeijing100089China
- School of Clinical MedicineWeifang Medical UniversityWeifang261053China
| | - Dingxia Shen
- Department of Laboratory Medicinethe First Medical CentreChinese People’s Liberation Army (PLA) General HospitalBeijing100853China
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Wang P, Li Y, Gao L, Tang X, Zheng D, Wu K, Wang L, Guo P, Ye F. In vitro characterization and molecular epidemiology of Cryptococcus spp. isolates from non-HIV patients in Guangdong, China. Front Microbiol 2024; 14:1295363. [PMID: 38287960 PMCID: PMC10823435 DOI: 10.3389/fmicb.2023.1295363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Accepted: 12/27/2023] [Indexed: 01/31/2024] Open
Abstract
Background The burden of cryptococcosis in mainland China is enormous. However, the in vitro characterization and molecular epidemiology in Guangdong, a key region with a high incidence of fungal infection in China, are not clear. Methods From January 1, 2010, to March 31, 2019, clinical strains of Cryptococcus were collected from six medical centres in Guangdong. The clinical information and characteristics of the strains were analysed. Furthermore, molecular types were determined. Results A total of 84 strains were collected, mostly from male and young or middle-aged adult patients. Pulmonary and cerebral infections (82.1%) were most common. All strains were Cryptococcus neoformans, grew well at 37°C and had capsules around their cells. One melanin- and urea- and one melanin+ and urea- variants were found. Although most strains exhibited a low minimum inhibitory concentration (MIC) value for voriconazole (mean: 0.04 μg/mL) and posaconazole (mean: 0.12 μg/mL), the results for these isolates showed a high degree of variation in the MIC values of fluconazole and 5-fluorocytosine, and resistance was observed for 4 out of 6 drugs. A significant proportion of these strains had MIC values near the ECV values, particularly in the case of amphotericin B. The proportion of strains near the clinical breakpoints was as follows: fluconazole: 3.66%; voriconazole: 3.66%; itraconazole: 6.10%; posaconazole: 13.41%; amphotericin B: 84.15%; 5-fluorocytosine: 2.44%. These strains were highly homogeneous and were dominated by the Grubii variant (95.2%), VNI (94.0%), α mating (100%), and ST5 (89.3%) genotypes. Other rare types, including ST4, 31, 278, 7, 57 and 106, were also found. Conclusion Phenotypically variant and non-wild-type strains were found in Guangdong, and a significant proportion of these strains had MIC values near the ECV values towards the 6 antifungal drugs, and resistance was observed for 4 out of 6 drugs. The molecular type was highly homogeneous but compositionally diverse, with rare types found. Enhanced surveillance of the aetiology and evolution and continuous monitoring of antifungal susceptibility are needed to provide references for decision-making in the health sector and optimization of disease prevention and control.
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Affiliation(s)
- Penglei Wang
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, National Center for Respiratory Medicine, Guangzhou, China
- Department of Respiratory Medicine, Longgang Central Hospital, Shenzhen, China
| | - Yongming Li
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, National Center for Respiratory Medicine, Guangzhou, China
| | - Lei Gao
- Microscopy Core Facility, Biomedical Research Core Facilities, Westlake University, Hangzhou, China
| | - Xiang Tang
- Intensive Care Unit, Guangzhou First People's Hospital, Guangzhou, China
| | - Dandian Zheng
- Department of Hematology Oncology, Jieyang City People's Hospital, Jieyang, China
| | - Kuihai Wu
- Clinical Medicine Laboratory, Foshan City First People's Hospital, Foshan, China
| | - Luxia Wang
- Clinical Medicine Laboratory, Southern Military Region General Hospital, Guangzhou, China
| | - Penghao Guo
- Clinical Medicine Laboratory, Sun Yat-sen University First Affiliated Hospital, Guangzhou, China
| | - Feng Ye
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, National Center for Respiratory Medicine, Guangzhou, China
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Albuquerque P, de Sousa HR, de Oliveira Frazão S, do Nascimento Miranda LV, Paes HC, Pereira IS, Nicola AM. Measuring Laccase Activity and Melanin Production in Cryptococcus neoformans. Methods Mol Biol 2024; 2775:257-268. [PMID: 38758323 DOI: 10.1007/978-1-0716-3722-7_17] [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
Melanin is a complex dark pigment synthetized by the phenoloxidase enzyme laccase in Cryptococcus neoformans. In vitro, this enzyme oxidizes exogenous catecholamines to produce melanin that may be secreted or incorporated into the fungal cell wall. This pigment has multiple roles in C. neoformans virulence during its interaction with different hosts and probably also in protecting fungal cells in the environment against predation and oxidative and radiation stresses, among others. However, it is important to note that laccase also has melanin-independent roles in C. neoformans interactions with host cells. In this chapter, we describe a quantitative laccase assay and a method for evaluating the kinetics of melanin production in C. neoformans colonies.
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Affiliation(s)
| | | | | | | | - Hugo Costa Paes
- Faculty of Medicine, University of Brasília, Brasília, DF, Brazil
| | - Ildinete Silva Pereira
- Institute of Biology, Department of Cell Biology, University of Brasília, Brasília, DF, Brazil
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7
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Agustinho DP, Brown HL, Chen G, Gaylord EA, Geddes-McAlister J, Brent MR, Doering TL. Unbiased discovery of natural sequence variants that influence fungal virulence. Cell Host Microbe 2023; 31:1910-1920.e5. [PMID: 37898126 PMCID: PMC10842055 DOI: 10.1016/j.chom.2023.10.002] [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: 05/23/2023] [Revised: 08/18/2023] [Accepted: 10/02/2023] [Indexed: 10/30/2023]
Abstract
Isolates of Cryptococcus neoformans, a fungal pathogen that kills over 112,000 people each year, differ from a 19-Mb reference genome at a few thousand up to almost a million DNA sequence positions. We used bulked segregant analysis and association analysis, genetic methods that require no prior knowledge of sequence function, to address the key question of which naturally occurring sequence variants influence fungal virulence. We identified a region containing such variants, prioritized them, and engineered strains to test our findings in a mouse model of infection. At one locus, we identified a 4-nt variant in the PDE2 gene that occurs in common laboratory strains and severely truncates the encoded phosphodiesterase. The resulting loss of phosphodiesterase activity significantly impacts virulence. Our studies demonstrate a powerful and unbiased strategy for identifying key genomic regions in the absence of prior information and provide significant sequence and strain resources to the community.
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Affiliation(s)
- Daniel Paiva Agustinho
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Holly Leanne Brown
- Department of Computer Science & Engineering, Washington University, St. Louis, MO 63130, USA
| | - Guohua Chen
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Elizabeth Anne Gaylord
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | | | - Michael Richard Brent
- Department of Computer Science & Engineering, Washington University, St. Louis, MO 63130, USA; Department of Genetics and Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Tamara Lea Doering
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
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Ristow LC, Jezewski AJ, Chadwick BJ, Stamnes MA, Lin X, Krysan DJ. Cryptococcus neoformans adapts to the host environment through TOR-mediated remodeling of phospholipid asymmetry. Nat Commun 2023; 14:6587. [PMID: 37852972 PMCID: PMC10584969 DOI: 10.1038/s41467-023-42318-y] [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: 04/17/2023] [Accepted: 10/06/2023] [Indexed: 10/20/2023] Open
Abstract
Cryptococcus spp. are environmental fungi that first must adapt to the host environment before they can cause life-threatening meningitis in immunocompromised patients. Host CO2 concentrations are 100-fold higher than the external environment and strains unable to grow at host CO2 concentrations are not pathogenic. Using a genetic screening and transcriptional profiling approach, we report that the TOR pathway is critical for C. neoformans adaptation to host CO2 partly through Ypk1-dependent remodeling of phosphatidylserine asymmetry at the plasma membrane. We also describe a C. neoformans ABC/PDR transporter (PDR9) that is highly expressed in CO2-sensitive environmental strains, suppresses CO2-induced phosphatidylserine/phospholipid remodeling, and increases susceptibility to host concentrations of CO2. Interestingly, regulation of plasma membrane lipid asymmetry by the TOR-Ypk1 axis is distinct in C. neoformans compared to S. cerevisiae. Finally, host CO2 concentrations suppress the C. neoformans pathways that respond to host temperature (Mpk1) and pH (Rim101), indicating that host adaptation requires a stringent balance among distinct stress responses.
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Affiliation(s)
- Laura C Ristow
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Andrew J Jezewski
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | | | - Mark A Stamnes
- Department of Molecular Physiology and Biophysics, Caver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Xiaorong Lin
- Department of Plant Biology, University of Georgia, Athens, GA, 30602, USA
- Department of Microbiology, University of Georgia, Athens, GA, 30602, USA
| | - Damian J Krysan
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA.
- Department of Molecular Physiology and Biophysics, Caver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA.
- Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA.
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Onyishi CU, Desanti GE, Wilkinson AL, Lara-Reyna S, Frickel EM, Fejer G, Christophe OD, Bryant CE, Mukhopadhyay S, Gordon S, May RC. Toll-like receptor 4 and macrophage scavenger receptor 1 crosstalk regulates phagocytosis of a fungal pathogen. Nat Commun 2023; 14:4895. [PMID: 37580395 PMCID: PMC10425417 DOI: 10.1038/s41467-023-40635-w] [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: 01/27/2023] [Accepted: 08/03/2023] [Indexed: 08/16/2023] Open
Abstract
The opportunistic fungal pathogen Cryptococcus neoformans causes lethal infections in immunocompromised patients. Macrophages are central to the host response to cryptococci; however, it is unclear how C. neoformans is recognised and phagocytosed by macrophages. Here we investigate the role of TLR4 in the non-opsonic phagocytosis of C. neoformans. We find that loss of TLR4 function unexpectedly increases phagocytosis of non-opsonised cryptococci by murine and human macrophages. The increased phagocytosis observed in Tlr4-/- cells was dampened by pre-treatment of macrophages with oxidised-LDL, a known ligand of scavenger receptors. The scavenger receptor, macrophage scavenger receptor 1 (MSR1) (also known as SR-A1 or CD204) was upregulated in Tlr4-/- macrophages. Genetic ablation of MSR1 resulted in a 75% decrease in phagocytosis of non-opsonised cryptococci, strongly suggesting that it is a key non-opsonic receptor for this pathogen. We go on to show that MSR1-mediated uptake likely involves the formation of a multimolecular signalling complex involving FcγR leading to SYK, PI3K, p38 and ERK1/2 activation to drive actin remodelling and phagocytosis. Altogether, our data indicate a hitherto unidentified role for TLR4/MSR1 crosstalk in the non-opsonic phagocytosis of C. neoformans.
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Affiliation(s)
- Chinaemerem U Onyishi
- Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Guillaume E Desanti
- Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Alex L Wilkinson
- Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Samuel Lara-Reyna
- Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Eva-Maria Frickel
- Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Gyorgy Fejer
- School of Biomedical Sciences, Faculty of Health, University of Plymouth, Plymouth, United Kingdom
| | - Olivier D Christophe
- Université Paris-Saclay, INSERM, Hémostase inflammation thrombose HITH U1176, 94276, Le Kremlin-Bicêtre, France
| | - Clare E Bryant
- University of Cambridge, Department of Medicine, Box 157, Level 5, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, United Kingdom
| | - Subhankar Mukhopadhyay
- Peter Gorer Department of Immunobiology, School of Immunology & Microbial Sciences, King's College London, London, SE1 9RT, United Kingdom
| | - Siamon Gordon
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Robin C May
- Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom.
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Hansakon A, Jeerawattanawart S, Angkasekwinai P. Differential and cooperative effects of IL-25 and IL-33 on T helper cells contribute to cryptococcal virulence and brain infection. Sci Rep 2023; 13:9895. [PMID: 37337050 DOI: 10.1038/s41598-023-37158-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 06/16/2023] [Indexed: 06/21/2023] Open
Abstract
The epithelial cell-derived cytokines IL-33 and IL-25 are important mediators in driving type-2 inflammation during C. neoformans infection. Nevertheless, the impact of these cytokines in regulating host T helper cell response during C. neoformans infection is still unclear. We observed that C. neoformans infection promoted a predominant increase of T helper cells that co-expressed IL-25 and IL-33 receptors within the lung during the late infection phase. A comparative transcriptomic analysis of effector T helper cells co-treated with IL-25 and IL-33 revealed a cooperative effect of these cytokines in promoting IL-13 gene expression. Without IL-25 receptor signaling, IL-33 treatment upregulated Th1-associated genes and genes associated with nucleotide metabolism. By contrast, IL-25 had a unique effect in enhancing type-2 cytokines IL-5 and IL-9 and chemokine CCL24, as well as genes in the pathways that are associated with L-arginine metabolisms. Interestingly, this pathogenic T helper cell population that expressed IL-25 and IL-33 receptors was greatly enriched in mice that were infected with high cryptococcal virulence and associated with fungal burdens in the brain. Therefore, our data further provide the additional function of IL-25 and IL-33 in potentiating cryptococcal brain dissemination.
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Affiliation(s)
- Adithap Hansakon
- Department of Medical Technology, Faculty of Allied Health Sciences, Thammasat University, Pathum Thani, 12120, Thailand
- Chulabhorn International College of Medicine, Thammasat University, Pathum Thani, 12120, Thailand
| | - Siranart Jeerawattanawart
- Department of Medical Technology, Faculty of Allied Health Sciences, Thammasat University, Pathum Thani, 12120, Thailand
- Graduate Program in Biomedical Science, Faculty of Allied Health Sciences, Thammasat University, Pathum Thani, 12120, Thailand
| | - Pornpimon Angkasekwinai
- Department of Medical Technology, Faculty of Allied Health Sciences, Thammasat University, Pathum Thani, 12120, Thailand.
- Research Unit in Molecular Pathogenesis and Immunology of Infectious Diseases, Thammasat University, Pathum Thani, 12120, Thailand.
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11
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Strickland AB, Chen Y, Sun D, Shi M. Alternatively activated lung alveolar and interstitial macrophages promote fungal growth. iScience 2023; 26:106717. [PMID: 37216116 PMCID: PMC10193231 DOI: 10.1016/j.isci.2023.106717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 03/03/2023] [Accepted: 04/18/2023] [Indexed: 05/24/2023] Open
Abstract
How lung macrophages, especially interstitial macrophages (IMs), respond to invading pathogens remains elusive. Here, we show that mice exhibited a rapid and substantial expansion of macrophages, especially CX3CR1+ IMs, in the lung following infection with Cryptococcus neoformans, a pathogenic fungus leading to high mortality among patients with HIV/AIDS. The IM expansion correlated with enhanced CSF1 and IL-4 production and was affected by the deficiency of CCR2 or Nr4a1. Both alveolar macrophages (AMs) and IMs were observed to harbor C. neoformans and became alternatively activated following infection, with IMs being more polarized. The absence of AMs by genetically disrupting CSF2 signaling reduced fungal loads in the lung and prolonged the survival of infected mice. Likewise, infected mice depleted of IMs by the CSF1 receptor inhibitor PLX5622 displayed significantly lower pulmonary fungal burdens. Thus, C. neoformans infection induces alternative activation of both AMs and IMs, which facilitates fungal growth in the lung.
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Affiliation(s)
- Ashley B. Strickland
- Division of Immunology, Virginia-Maryland College of Veterinary Medicine, Maryland Pathogen Research Institute, University of Maryland, College Park, MD 20742, USA
| | - Yanli Chen
- Division of Immunology, Virginia-Maryland College of Veterinary Medicine, Maryland Pathogen Research Institute, University of Maryland, College Park, MD 20742, USA
| | - Donglei Sun
- Division of Immunology, Virginia-Maryland College of Veterinary Medicine, Maryland Pathogen Research Institute, University of Maryland, College Park, MD 20742, USA
| | - Meiqing Shi
- Division of Immunology, Virginia-Maryland College of Veterinary Medicine, Maryland Pathogen Research Institute, University of Maryland, College Park, MD 20742, USA
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12
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Jackson KM, Ding M, Nielsen K. Importance of Clinical Isolates in Cryptococcus neoformans Research. J Fungi (Basel) 2023; 9:364. [PMID: 36983532 PMCID: PMC10056780 DOI: 10.3390/jof9030364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 03/09/2023] [Accepted: 03/13/2023] [Indexed: 03/19/2023] Open
Abstract
The human pathogenic fungus Cryptococcus neoformans is a global health concern. Previous research in the field has focused on studies using reference strains to identify virulence factors, generate mutant libraries, define genomic structures, and perform functional studies. In this review, we discuss the benefits and drawbacks of using reference strains to study C. neoformans, describe how the study of clinical isolates has expanded our understanding of pathogenesis, and highlight how studies using clinical isolates can further develop our understanding of the host-pathogen interaction during C. neoformans infection.
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Affiliation(s)
| | | | - Kirsten Nielsen
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN 55455, USA
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13
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Smith DFQ, Dragotakes Q, Kulkarni M, Hardwick JM, Casadevall A. Galleria mellonella immune melanization is fungicidal during infection. Commun Biol 2022; 5:1364. [PMID: 36510005 PMCID: PMC9744840 DOI: 10.1038/s42003-022-04340-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 12/05/2022] [Indexed: 12/14/2022] Open
Abstract
A key component of the insect immune response is melanin production, including within nodules, or aggregations of immune cells surrounding microbes. Melanization produces oxidative and toxic intermediates that limit microbial infections. However, a direct fungicidal role of melanin during infection has not been demonstrated. We previously reported that the fungus Cryptococcus neoformans is encapsulated with melanin within nodules of Galleria mellonella hosts. Here we developed techniques to study melanin's role during C. neoformans infection in G. mellonella. We provided evidence that in vivo melanin-encapsulation was fungicidal. To further study immune melanization, we applied tissue-clearing techniques to visualize melanized nodules in situ throughout the larvae. Further, we developed a time-lapse microscopy protocol to visualize the melanization kinetics in extracted hemolymph following fungal exposure. Using this technique, we found that cryptococcal melanin and laccase enhance immune melanization. We extended this approach to study the fungal pathogens Candida albicans and Candida auris. We find that the yeast morphologies of these fungi elicited robust melanization responses, while hyphal and pseudohyphal morphologies were melanin-evasive. Approximately 23% of melanin-encapsulated C. albicans yeast can survive and breakthrough the encapsulation. Overall, our results provide direct evidence that immune melanization functions as a direct antifungal mechanism in G. mellonella.
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Affiliation(s)
- Daniel F. Q. Smith
- grid.21107.350000 0001 2171 9311W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205 USA
| | - Quigly Dragotakes
- grid.21107.350000 0001 2171 9311W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205 USA
| | - Madhura Kulkarni
- grid.21107.350000 0001 2171 9311W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205 USA
| | - J. Marie Hardwick
- grid.21107.350000 0001 2171 9311W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205 USA
| | - Arturo Casadevall
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA.
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14
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Yang C, Huang Y, Zhou Y, Zang X, Deng H, Liu Y, Shen D, Xue X. Cryptococcus escapes host immunity: What do we know? Front Cell Infect Microbiol 2022; 12:1041036. [PMID: 36310879 PMCID: PMC9606624 DOI: 10.3389/fcimb.2022.1041036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Accepted: 09/30/2022] [Indexed: 11/13/2022] Open
Abstract
Cryptococcus is an invasive fungus that seriously endangers human life and health, with a complex and well-established immune-escaping mechanism that interferes with the function of the host immune system. Cryptococcus can attenuate the host’s correct recognition of the fungal antigen and escape the immune response mediated by host phagocytes, innate lymphoid cells, T lymphocytes, B lymphocytes with antibodies, and peripheral cytokines. In addition, the capsule, melanin, dormancy, Titan cells, biofilm, and other related structures of Cryptococcus are also involved in the process of escaping the host’s immunity, as well as enhancing the ability of Cryptococcus to infect the host.
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Affiliation(s)
- Chen Yang
- Department of Laboratory Medicine, the First Medical Centre, Chinese People's Liberation Army (PLA) General Hospital, Beijing, China
| | - Yemei Huang
- Department of Respiratory and Critical Care, Beijing Shijitan Hospital, Capital Medical University, Peking University Ninth School of Clinical Medicine, Beijing, China
| | - Yangyu Zhou
- Department of Respiratory and Critical Care, Beijing Shijitan Hospital, Capital Medical University, Peking University Ninth School of Clinical Medicine, Beijing, China
| | - Xuelei Zang
- Department of Respiratory and Critical Care, Beijing Shijitan Hospital, Capital Medical University, Peking University Ninth School of Clinical Medicine, Beijing, China
| | - Hengyu Deng
- School of Clinical Medicine, Weifang Medical University, Weifang, China
| | - Yitong Liu
- Department of Respiratory and Critical Care, Beijing Shijitan Hospital, Capital Medical University, Peking University Ninth School of Clinical Medicine, Beijing, China
| | - Dingxia Shen
- Department of Laboratory Medicine, the First Medical Centre, Chinese People's Liberation Army (PLA) General Hospital, Beijing, China
- *Correspondence: Dingxia Shen, ; Xinying Xue,
| | - Xinying Xue
- Department of Respiratory and Critical Care, Beijing Shijitan Hospital, Capital Medical University, Peking University Ninth School of Clinical Medicine, Beijing, China
- School of Clinical Medicine, Weifang Medical University, Weifang, China
- *Correspondence: Dingxia Shen, ; Xinying Xue,
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15
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Cryptococcus neoformans Infection in the Central Nervous System: The Battle between Host and Pathogen. J Fungi (Basel) 2022; 8:jof8101069. [PMID: 36294634 PMCID: PMC9605252 DOI: 10.3390/jof8101069] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 09/28/2022] [Accepted: 10/07/2022] [Indexed: 11/17/2022] Open
Abstract
Cryptococcus neoformans (C. neoformans) is a pathogenic fungus with a global distribution. Humans become infected by inhaling the fungus from the environment, and the fungus initially colonizes the lungs. If the immune system fails to contain C. neoformans in the lungs, the fungus can disseminate to the blood and invade the central nervous system, resulting in fatal meningoencephalitis particularly in immunocompromised individuals including HIV/AIDS patients. Following brain invasion, C. neoformans will encounter host defenses involving resident as well as recruited immune cells in the brain. To overcome host defenses, C. neoformans possesses multiple virulence factors capable of modulating immune responses. The outcome of the interactions between the host and C. neoformans will determine the disease progression. In this review, we describe the current understanding of how C. neoformans migrates to the brain across the blood–brain barrier, and how the host immune system responds to the invading organism in the brain. We will also discuss the virulence factors that C. neoformans uses to modulate host immune responses.
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16
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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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17
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Kassaza K, Wasswa F, Nielsen K, Bazira J. Cryptococcus neoformans Genotypic Diversity and Disease Outcome among HIV Patients in Africa. J Fungi (Basel) 2022; 8:jof8070734. [PMID: 35887489 PMCID: PMC9325144 DOI: 10.3390/jof8070734] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 06/24/2022] [Accepted: 07/06/2022] [Indexed: 11/16/2022] Open
Abstract
Cryptococcal meningoencephalitis, a disease with poor patient outcomes, remains the most prevalent invasive fungal infection worldwide, accounting for approximately 180,000 deaths each year. In several areas of sub-Saharan Africa with the highest HIV prevalence, cryptococcal meningitis is the leading cause of community-acquired meningitis, with a high mortality among HIV-infected individuals. Recent studies show that patient disease outcomes are impacted by the genetics of the infecting isolate. Yet, there is still limited knowledge of how these genotypic variations contribute to clinical disease outcome. Further, it is unclear how the genetic heterogeneity of C. neoformans and the extensive phenotypic variation observed between and within isolates affects infection and disease. In this review, we discuss current knowledge of how various genotypes impact disease progression and patient outcome in HIV-positive populations in sub-Saharan African, a setting with a high burden of cryptococcosis.
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Affiliation(s)
- Kennedy Kassaza
- Department of Microbiology and Parasitology, Mbarara University of Science and Technology, Mbarara P.O. Box 1410, Uganda; (K.K.); (F.W.)
| | - Fredrickson Wasswa
- Department of Microbiology and Parasitology, Mbarara University of Science and Technology, Mbarara P.O. Box 1410, Uganda; (K.K.); (F.W.)
| | - Kirsten Nielsen
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN 55455, USA
- Correspondence: (K.N.); (J.B.)
| | - Joel Bazira
- Department of Microbiology and Parasitology, Mbarara University of Science and Technology, Mbarara P.O. Box 1410, Uganda; (K.K.); (F.W.)
- Correspondence: (K.N.); (J.B.)
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18
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de Sousa HR, de Oliveira GP, Frazão SDO, Gorgonha KCDM, Rosa CP, Garcez EM, Lucas J, Correia AF, de Freitas WF, Borges HM, de Brito Alves LG, Paes HC, Trilles L, Lazera MDS, Teixeira MDM, Pinto VL, Felipe MSS, Casadevall A, Silva-Pereira I, Albuquerque P, Nicola AM. Faster Cryptococcus Melanization Increases Virulence in Experimental and Human Cryptococcosis. J Fungi (Basel) 2022; 8:393. [PMID: 35448624 PMCID: PMC9029458 DOI: 10.3390/jof8040393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 03/26/2022] [Accepted: 03/29/2022] [Indexed: 12/10/2022] Open
Abstract
Cryptococcus spp. are human pathogens that cause 181,000 deaths per year. In this work, we systematically investigated the virulence attributes of Cryptococcus spp. clinical isolates and correlated them with patient data to better understand cryptococcosis. We collected 66 C. neoformans and 19 C. gattii clinical isolates and analyzed multiple virulence phenotypes and host-pathogen interaction outcomes. C. neoformans isolates tended to melanize faster and more intensely and produce thinner capsules in comparison with C. gattii. We also observed correlations that match previous studies, such as that between secreted laccase and disease outcome in patients. We measured Cryptococcus colony melanization kinetics, which followed a sigmoidal curve for most isolates, and showed that faster melanization correlated positively with LC3-associated phagocytosis evasion, virulence in Galleria mellonella and worse prognosis in humans. These results suggest that the speed of melanization, more than the total amount of melanin Cryptococcus spp. produces, is crucial for virulence.
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Affiliation(s)
- Herdson Renney de Sousa
- Faculty of Medicine, University of Brasília, Brasília 70910-900, DF, Brazil; (H.R.d.S.); (K.C.d.M.G.); (C.P.R.); (E.M.G.); (W.F.d.F.); (H.M.B.); (L.G.d.B.A.); (H.C.P.); (M.d.M.T.)
| | - Getúlio Pereira de Oliveira
- Division of Allergy and Inflammation, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA;
| | - Stefânia de Oliveira Frazão
- Laboratory of Molecular Biology of Pathogenic Fungi, Institute of Biological Sciences, University of Brasília, Brasília 70910-900, DF, Brazil; (S.d.O.F.); (I.S.-P.); (P.A.)
| | - Kaio César de Melo Gorgonha
- Faculty of Medicine, University of Brasília, Brasília 70910-900, DF, Brazil; (H.R.d.S.); (K.C.d.M.G.); (C.P.R.); (E.M.G.); (W.F.d.F.); (H.M.B.); (L.G.d.B.A.); (H.C.P.); (M.d.M.T.)
| | - Camila Pereira Rosa
- Faculty of Medicine, University of Brasília, Brasília 70910-900, DF, Brazil; (H.R.d.S.); (K.C.d.M.G.); (C.P.R.); (E.M.G.); (W.F.d.F.); (H.M.B.); (L.G.d.B.A.); (H.C.P.); (M.d.M.T.)
| | - Emãnuella Melgaço Garcez
- Faculty of Medicine, University of Brasília, Brasília 70910-900, DF, Brazil; (H.R.d.S.); (K.C.d.M.G.); (C.P.R.); (E.M.G.); (W.F.d.F.); (H.M.B.); (L.G.d.B.A.); (H.C.P.); (M.d.M.T.)
| | - Joaquim Lucas
- Oswaldo Cruz Foundation (Fiocruz–Brasília), Brasília 70904-130, DF, Brazil; (J.L.J.); (V.L.P.J.)
| | | | - Waleriano Ferreira de Freitas
- Faculty of Medicine, University of Brasília, Brasília 70910-900, DF, Brazil; (H.R.d.S.); (K.C.d.M.G.); (C.P.R.); (E.M.G.); (W.F.d.F.); (H.M.B.); (L.G.d.B.A.); (H.C.P.); (M.d.M.T.)
| | - Higor Matos Borges
- Faculty of Medicine, University of Brasília, Brasília 70910-900, DF, Brazil; (H.R.d.S.); (K.C.d.M.G.); (C.P.R.); (E.M.G.); (W.F.d.F.); (H.M.B.); (L.G.d.B.A.); (H.C.P.); (M.d.M.T.)
| | - Lucas Gomes de Brito Alves
- Faculty of Medicine, University of Brasília, Brasília 70910-900, DF, Brazil; (H.R.d.S.); (K.C.d.M.G.); (C.P.R.); (E.M.G.); (W.F.d.F.); (H.M.B.); (L.G.d.B.A.); (H.C.P.); (M.d.M.T.)
| | - Hugo Costa Paes
- Faculty of Medicine, University of Brasília, Brasília 70910-900, DF, Brazil; (H.R.d.S.); (K.C.d.M.G.); (C.P.R.); (E.M.G.); (W.F.d.F.); (H.M.B.); (L.G.d.B.A.); (H.C.P.); (M.d.M.T.)
| | - Luciana Trilles
- Mycology Laboratory, Evandro Chagas National Institute of Infectious Diseases, Oswaldo Cruz Foundation (Fiocruz–Rio de Janeiro), Rio de Janeiro 21045-900, RJ, Brazil; (L.T.); (M.d.S.L.)
| | - Márcia dos Santos Lazera
- Mycology Laboratory, Evandro Chagas National Institute of Infectious Diseases, Oswaldo Cruz Foundation (Fiocruz–Rio de Janeiro), Rio de Janeiro 21045-900, RJ, Brazil; (L.T.); (M.d.S.L.)
| | - Marcus de Melo Teixeira
- Faculty of Medicine, University of Brasília, Brasília 70910-900, DF, Brazil; (H.R.d.S.); (K.C.d.M.G.); (C.P.R.); (E.M.G.); (W.F.d.F.); (H.M.B.); (L.G.d.B.A.); (H.C.P.); (M.d.M.T.)
| | - Vitor Laerte Pinto
- Oswaldo Cruz Foundation (Fiocruz–Brasília), Brasília 70904-130, DF, Brazil; (J.L.J.); (V.L.P.J.)
| | - Maria Sueli Soares Felipe
- Graduate Program in Genomic Sciences and Biotechnology, Catholic University of Brasília, Brasília 70790-160, DF, Brazil;
| | - Arturo Casadevall
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA;
| | - Ildinete Silva-Pereira
- Laboratory of Molecular Biology of Pathogenic Fungi, Institute of Biological Sciences, University of Brasília, Brasília 70910-900, DF, Brazil; (S.d.O.F.); (I.S.-P.); (P.A.)
| | - Patrícia Albuquerque
- Laboratory of Molecular Biology of Pathogenic Fungi, Institute of Biological Sciences, University of Brasília, Brasília 70910-900, DF, Brazil; (S.d.O.F.); (I.S.-P.); (P.A.)
- Faculty of Ceilândia, University of Brasília, Brasília 72220-275, DF, Brazil
| | - André Moraes Nicola
- Faculty of Medicine, University of Brasília, Brasília 70910-900, DF, Brazil; (H.R.d.S.); (K.C.d.M.G.); (C.P.R.); (E.M.G.); (W.F.d.F.); (H.M.B.); (L.G.d.B.A.); (H.C.P.); (M.d.M.T.)
- Graduate Program in Genomic Sciences and Biotechnology, Catholic University of Brasília, Brasília 70790-160, DF, Brazil;
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Rathore SS, Sathiyamoorthy J, Lalitha C, Ramakrishnan J. A holistic review on Cryptococcus neoformans. Microb Pathog 2022; 166:105521. [DOI: 10.1016/j.micpath.2022.105521] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 04/06/2022] [Accepted: 04/06/2022] [Indexed: 12/21/2022]
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20
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Gene, virulence and related regulatory mechanisms in Cryptococcus gattii. Acta Biochim Biophys Sin (Shanghai) 2022; 54:593-603. [PMID: 35593469 PMCID: PMC9828318 DOI: 10.3724/abbs.2022029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Cryptococcus gattii is a kind of basidiomycetous yeast, which grows in human and animal hosts. C. gattii has four distinct genomes, VGI/AFLP4, VGII/AFLP6, VGIII/AFLP5, and VGIV/AFLP7. The virulence of C. gattii is closely associated with genotype and related stress-signaling pathways, but the pathogenic mechanism of C. gattii has not been fully identified. With the development of genomics and transcriptomics, the relationship among genes, regulatory mechanisms, virulence, and treatment is gradually being recognized. In this review, to better understand how C. gattii causes disease and to characterize hypervirulent C. gattii strains, we summarize the current understanding of C. gattii genotypes, phenotypes, virulence, and the regulatory mechanisms.
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21
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Wang Y, Pawar S, Dutta O, Wang K, Rivera A, Xue C. Macrophage Mediated Immunomodulation During Cryptococcus Pulmonary Infection. Front Cell Infect Microbiol 2022; 12:859049. [PMID: 35402316 PMCID: PMC8987709 DOI: 10.3389/fcimb.2022.859049] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 02/28/2022] [Indexed: 12/21/2022] Open
Abstract
Macrophages are key cellular components of innate immunity, acting as the first line of defense against pathogens to modulate homeostatic and inflammatory responses. They help clear pathogens and shape the T-cell response through the production of cytokines and chemokines. The facultative intracellular fungal pathogen Cryptococcus neoformans has developed a unique ability to interact with and manipulate host macrophages. These interactions dictate how Cryptococcus infection can remain latent or how dissemination within the host is achieved. In addition, differences in the activities of macrophages have been correlated with differential susceptibilities of hosts to Cryptococcus infection, highlighting the importance of macrophages in determining disease outcomes. There is now abundant information on the interaction between Cryptococcus and macrophages. In this review we discuss recent advances regarding macrophage origin, polarization, activation, and effector functions during Cryptococcus infection. The importance of these strategies in pathogenesis and the potential of immunotherapy for cryptococcosis treatment is also discussed.
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Affiliation(s)
- Yan Wang
- Public Health Research Institute, New Jersey Medical School, Rutgers University, Newark, NJ, United States
- Department of Microbiology and Immunology , Guangdong Medical University, Dongguan, China
| | - Siddhi Pawar
- Public Health Research Institute, New Jersey Medical School, Rutgers University, Newark, NJ, United States
| | - Orchi Dutta
- Public Health Research Institute, New Jersey Medical School, Rutgers University, Newark, NJ, United States
| | - Keyi Wang
- Center for Immunity and Inflammation, New Jersey Medical School, Rutgers University, Newark, NJ, United States
| | - Amariliz Rivera
- Center for Immunity and Inflammation, New Jersey Medical School, Rutgers University, Newark, NJ, United States
| | - Chaoyang Xue
- Public Health Research Institute, New Jersey Medical School, Rutgers University, Newark, NJ, United States
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22
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Lineages Derived from Cryptococcus neoformans Type Strain H99 Support a Link between the Capacity to Be Pleomorphic and Virulence. mBio 2022; 13:e0028322. [PMID: 35258331 PMCID: PMC9040854 DOI: 10.1128/mbio.00283-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The pathogenic yeast Cryptococcus neoformans causes nearly 200,000 deaths annually in immunocompromised individuals. Cryptococcus cells can undergo substantial morphological change during mammalian infection, including increased capsule and cell size, the release of shed capsule, and the production of titan (>10 μm), micro (<2 μm)-, and irregular cells. We examined phenotypic variation under conditions designed to simulate in vivo stress in a collection of nine lineages derived from the C. neoformans type strain H99. These lineages are highly genetically similar but have a range of virulence levels. Strains from hypervirulent lineages had a larger average capsule size, greater variation in cell size, and an increased production of microcells and shed capsule. We tested whether disruption of SGF29, which encodes a component of the SAGA histone acetylation complex that has previously been implicated in the hypervirulence of some lineages, also has a role in the production of morphological variants. Deletion of SGF29 in a lineage with intermediate virulence substantially increased its production of microcells and released capsule, consistent with a switch to hypervirulence. We further examined SGF29 in a set of 52 clinical isolates and found loss-of-function mutations were significantly correlated with patient death. Expansion of a TA repeat in the second intron of SGF29 was positively correlated with cell and capsule size, suggesting it also affects Sgf29 function. This study extends the evidence for a link between pleomorphism and virulence in Cryptococcus, with a likely role for epigenetic mechanisms mediated by SAGA-induced histone acetylation.
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Deciphering the Association among Pathogenicity, Production and Polymorphisms of Capsule/Melanin in Clinical Isolates of Cryptococcus neoformans var. grubii VNI. J Fungi (Basel) 2022; 8:jof8030245. [PMID: 35330247 PMCID: PMC8950468 DOI: 10.3390/jof8030245] [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] [Received: 12/23/2021] [Revised: 02/17/2022] [Accepted: 02/21/2022] [Indexed: 01/27/2023] Open
Abstract
Background: Cryptococcus neoformans is an opportunistic fungal pathogen that can cause meningitis in immunocompromised individuals. The objective of this work was to study the relationship between the phenotypes and genotypes of isolates of clinical origin from different cities in Colombia. Methods: Genome classification of 29 clinical isolates of C. neoformans var. grubii was performed using multilocus sequence typing (MLST), and genomic sequencing was used to genotype protein-coding genes. Pathogenicity was assessed in a larval model, and melanin production and capsule size were evaluated in vitro and in vivo. Results: Eleven MLST sequence types (STs) were found, the most frequent being ST69 (n = 9), ST2, ST93, and ST377 (each with n = 4). In the 29 isolates, different levels of pigmentation, capsule size and pathogenicity were observed. Isolates classified as highly pathogenic showed a tendency to exhibit larger increases in capsule size. In the analysis of polymorphisms, 48 non-synonymous variants located in the predicted functional domains of 39 genes were found to be associated with capsule size change, melanin, or pathogenicity. Conclusions: No clear patterns were found in the analysis of the phenotype and genotype of Cryptococcus. However, the data suggest that the increase in capsule size is a key variable for the differentiation of pathogenic isolates, regardless of the method used for its induction.
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Clinical features of invasive fungal disease in children with no underlying disease. Sci Rep 2022; 12:208. [PMID: 34996910 PMCID: PMC8742124 DOI: 10.1038/s41598-021-03099-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 08/18/2021] [Indexed: 11/08/2022] Open
Abstract
There is limited research into Invasive fungal disease (IFD) in children with no underlying disease. We undertook a retrospective study of children with IFD who did not suffer from another underlying disease, from June 2010 to March 2018 in Changsha, China. Nine children were identified. Eosinophil counts were elevated in six cases. The level of procalcitonin (PCT) was elevated in six cases. Fungal culture was positive in all patients, including eight cases of Cryptococcus neoformans and one case of Candida parapsilosis. 8.33 days following antifungal treatment, the body temperature of the eight patients affected by cryptococcal disease had returned to normal. Our study indicates that the primary pathogen in IFD was Cryptococcus neoformans in children who had no other underlying disease. Eosinophils can be considered to be indicators of cryptococcal infection. IFD in children with no other underlying disease has a satisfactory prognosis.
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Onyishi CU, May RC. Human immune polymorphisms associated with the risk of cryptococcal disease. Immunology 2021; 165:143-157. [PMID: 34716931 PMCID: PMC9426616 DOI: 10.1111/imm.13425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 10/07/2021] [Accepted: 10/16/2021] [Indexed: 11/29/2022] Open
Abstract
Cryptococcus neoformans is an opportunistic fungal pathogen that can cause lethal cryptococcal meningitis in immunocompromised individuals such as those with HIV/AIDS. In addition, cryptococcal infections occasionally arise in immunocompetent individuals or those with previously undiagnosed immunodeficiencies. The course of cryptococcosis is highly variable in both patient groups, and there is rapidly growing evidence that genetic polymorphisms may have a significant impact on the trajectory of disease. Here, we review what is currently known about the nature of these polymorphisms and their impact on host response to C. neoformans infection. Thus far, polymorphisms in Fc gamma receptors, mannose‐binding lectin, Dectin‐2, Toll‐like receptors and macrophage colony‐stimulating factor have been associated with susceptibility to cryptococcal disease. Notably, however, in some cases the impact of these polymorphisms depends on the genetic background of the population; for example, the FCGR3A 158 F/V polymorphism was associated with an increased risk of cryptococcal disease in both HIV‐positive and HIV‐negative white populations, but not in Han Chinese patients. In most cases, the precise mechanism by which the identified polymorphisms influence disease progression remains unclear, although impaired fungal recognition and phagocytosis by innate immune cells appears to play a major role. Finally, we highlight outstanding questions in the field and emphasize the need for future research to include more diverse populations in their genetic association studies.
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Affiliation(s)
- Chinaemerem U Onyishi
- Institute of Microbiology & Infection, School of Biosciences, University of Birmingham, Birmingham, UK
| | - Robin C May
- Institute of Microbiology & Infection, School of Biosciences, University of Birmingham, Birmingham, UK
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Phenotypic Plasticity in the Productions of Virulence Factors Within and Among Serotypes in the Cryptococcus neoformans Species Complex. Mycopathologia 2021; 187:65-83. [PMID: 34697686 DOI: 10.1007/s11046-021-00597-3] [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: 01/05/2021] [Accepted: 10/12/2021] [Indexed: 10/20/2022]
Abstract
The Cryptococcus neoformans species complex (CNSC) is a common opportunistic human fungal pathogen and the most frequent cause of fungal meningitis. There are three major serotypes in CNSC: A, D, and their hybrids AD, and they have different geographic distributions and medical significance. Melanin pigment and a polysaccharide capsule are the two major virulence factors in CNSC. However, the relationships between serotype and virulence factor production and how environmental factors might impact their relationships are not known. This study investigated the expressions of melanin and capsular polysaccharide in a genetically diverse group of CNSC strains and how their phenotypic expressions were influenced by oxidative and nitrosative stress levels. We found significant differences in melanin and capsular polysaccharide productions among serotypes and across stress conditions. Under oxidative stress, the laboratory hybrids exhibited the highest phenotypic plasticity for melanin production while serotype A showed the highest for capsular polysaccharide production. In contrast, serotype D exhibited the highest phenotypic plasticity for capsular polysaccharide production and clinical serotype AD the highest phenotypic plasticity for melanin production under nitrosative stress. These results demonstrated that different serotypes have different environmental condition-specific mechanisms to modulate the expression of virulence factors.
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de Sousa HR, de Frazão S, de Oliveira Júnior GP, Albuquerque P, Nicola AM. Cryptococcal Virulence in Humans: Learning From Translational Studies With Clinical Isolates. Front Cell Infect Microbiol 2021; 11:657502. [PMID: 33968804 PMCID: PMC8097041 DOI: 10.3389/fcimb.2021.657502] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 03/31/2021] [Indexed: 01/17/2023] Open
Abstract
Cryptococcosis, an invasive mycosis caused by Cryptococcus spp, kills between 20% and 70% of the patients who develop it. There are no vaccines for prevention, and treatment is based on a limited number of antifungals. Studying fungal virulence and how the host responds to infection could lead to new therapies, improving outcomes for patients. The biggest challenge, however, is that experimental cryptococcosis models do not completely recapitulate human disease, while human experiments are limited due to ethical reasons. To overcome this challenge, one of the approaches used by researchers and clinicians is to: 1) collect cryptococcal clinical isolates and associated patient data; 2) study the set of isolates in the laboratory (virulence and host-pathogen interaction variables, molecular markers); 3) correlate the laboratory and patient data to understand the roles fungal attributes play in the human disease. Here we review studies that have shed light on the cryptococcosis pathophysiology using these approaches, with a special focus on human disease. Isolates that more effectively evade macrophage responses, that secrete more laccase, melanize faster and have larger capsules in the cerebrospinal fluid are associated with poorer patient outcomes. Additionally, molecular studies have also shown that cryptococcal clades vary in virulence, with clinical impact. Limitations of those studies include the use of a small number of isolates or retrospectively collected clinical data. The fact that they resulted in very important information is a reflection of the impact this strategy has in understanding cryptococcosis and calls for international collaboration that could boost our knowledge.
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Affiliation(s)
- Herdson Renney de Sousa
- Microbiology, Immunology and Biotechnology Laboratory, Faculty of Medicine, University of Brasília, Brasília, Brazil
| | - Stefânia de Frazão
- Laboratory of Molecular Biology of Pathogenic Fungi, Department of Cell Biology, Institute of Biological Sciences, University of Brasília, Brasília, Brazil
| | - Getúlio Pereira de Oliveira Júnior
- Division of Allergy and Inflammation, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - Patrícia Albuquerque
- Microbiology, Immunology and Biotechnology Laboratory, Faculty of Medicine, University of Brasília, Brasília, Brazil
- Laboratory of Molecular Biology of Pathogenic Fungi, Department of Cell Biology, Institute of Biological Sciences, University of Brasília, Brasília, Brazil
- Faculty of Ceilândia, University of Brasília, Brasília, Brazil
| | - André Moraes Nicola
- Microbiology, Immunology and Biotechnology Laboratory, Faculty of Medicine, University of Brasília, Brasília, Brazil
- Graduate Program in Genomic Sciences and Biotechnology, Catholic University of Brasília, Brasília, Brazil
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Liu S, Youngchim S, Zamith-Miranda D, Nosanchuk JD. Fungal Melanin and the Mammalian Immune System. J Fungi (Basel) 2021; 7:jof7040264. [PMID: 33807336 PMCID: PMC8066723 DOI: 10.3390/jof7040264] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 03/25/2021] [Accepted: 03/26/2021] [Indexed: 02/06/2023] Open
Abstract
Melanins are ubiquitous complex polymers that are commonly known in humans to cause pigmentation of our skin. Melanins are also present in bacteria, fungi, and helminths. In this review, we will describe the diverse interactions of fungal melanin with the mammalian immune system. We will particularly focus on Cryptococcus neoformans and also discuss other major melanotic pathogenic fungi. Melanin interacts with the immune system through diverse pathways, reducing the effectiveness of phagocytic cells, binding effector molecules and antifungals, and modifying complement and antibody responses.
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Affiliation(s)
- Sichen Liu
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (S.L.); (D.Z.-M.)
| | - Sirida Youngchim
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand;
| | - Daniel Zamith-Miranda
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (S.L.); (D.Z.-M.)
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Joshua D. Nosanchuk
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (S.L.); (D.Z.-M.)
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Correspondence:
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The interplay of phenotype and genotype in Cryptococcus neoformans disease. Biosci Rep 2021; 40:226594. [PMID: 33021310 PMCID: PMC7569153 DOI: 10.1042/bsr20190337] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 09/23/2020] [Accepted: 10/06/2020] [Indexed: 12/17/2022] Open
Abstract
Cryptococcus neoformans is an opportunistic fungal pathogen that causes life-threatening meningitis primarily in immunocompromised individuals. In order to survive and proliferate during infection, C. neoformans must adapt to a variety of stresses it encounters within the host. Patient outcome depends on the interaction between the pathogen and the host. Understanding the mechanisms that C. neoformans uses to facilitate adaptation to the host and promote pathogenesis is necessary to better predict disease severity and establish proper treatment. Several virulence phenotypes have been characterized in C. neoformans, but the field still lacks a complete understanding of how genotype and phenotype contribute to clinical outcome. Furthermore, while it is known that C. neoformans genotype impacts patient outcome, the mechanisms remain unknown. This lack of understanding may be due to the genetic heterogeneity of C. neoformans and the extensive phenotypic variation observed between and within isolates during infection. In this review, we summarize the current understanding of how the various genotypes and phenotypes observed in C. neoformans correlate with human disease progression in the context of patient outcome and recurrence. We also postulate the mechanisms underlying the genetic and phenotypic changes that occur in vivo to promote rapid adaptation in the host.
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Associations between Cryptococcus Genotypes, Phenotypes, and Clinical Parameters of Human Disease: A Review. J Fungi (Basel) 2021; 7:jof7040260. [PMID: 33808500 PMCID: PMC8067209 DOI: 10.3390/jof7040260] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 03/25/2021] [Accepted: 03/25/2021] [Indexed: 12/11/2022] Open
Abstract
The genus Cryptococcus contains two primary species complexes that are significant opportunistic human fungal pathogens: C. neoformans and C. gattii. In humans, cryptococcosis can manifest in many ways, but most often results in either pulmonary or central nervous system disease. Patients with cryptococcosis can display a variety of symptoms on a spectrum of severity because of the interaction between yeast and host. The bulk of our knowledge regarding Cryptococcus and the mechanisms of disease stem from in vitro experiments and in vivo animal models that make a fair attempt, but do not recapitulate the conditions inside the human host. To better understand the dynamics of initiation and progression in cryptococcal disease, it is important to study the genetic and phenotypic differences in the context of human infection to identify the human and fungal risk factors that contribute to pathogenesis and poor clinical outcomes. In this review, we summarize the current understanding of the different clinical presentations and health outcomes that are associated with pathogenicity and virulence of cryptococcal strains with respect to specific genotypes and phenotypes.
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F. Q. Smith D, Casadevall A. Fungal immunity and pathogenesis in mammals versus the invertebrate model organism Galleria mellonella. Pathog Dis 2021; 79:ftab013. [PMID: 33544836 PMCID: PMC7981337 DOI: 10.1093/femspd/ftab013] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 02/03/2021] [Indexed: 02/07/2023] Open
Abstract
In recent decades, Galleria mellonella (Lepidoptera: Pyralidae) have emerged as a model system to explore experimental aspects of fungal pathogenesis. The benefits of the G. mellonella model include being faster, cheaper, higher throughput and easier compared with vertebrate models. Additionally, as invertebrates, their use is subject to fewer ethical and regulatory issues. However, for G. mellonella models to provide meaningful insight into fungal pathogenesis, the G. mellonella-fungal interactions must be comparable to mammalian-fungal interactions. Indeed, as discussed in the review, studies suggest that G. mellonella and mammalian immune systems share many similarities, and fungal virulence factors show conserved functions in both hosts. While the moth model has opened novel research areas, many comparisons are superficial and leave large gaps of knowledge that need to be addressed concerning specific mechanisms underlying G. mellonella-fungal interactions. Closing these gaps in understanding will strengthen G. mellonella as a model for fungal virulence in the upcoming years. In this review, we provide comprehensive comparisons between fungal pathogenesis in mammals and G. mellonella from immunological and virulence perspectives. When information on an antifungal immune component is unknown in G. mellonella, we include findings from other well-studied Lepidoptera. We hope that by outlining this information available in related species, we highlight areas of needed research and provide a framework for understanding G. mellonella immunity and fungal interactions.
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Affiliation(s)
- Daniel F. Q. Smith
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Arturo Casadevall
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
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Oliveira RKDM, Hurtado FA, Gomes PH, Puglia LL, Ferreira FF, Ranjan K, Albuquerque P, Poças-Fonseca MJ, Silva-Pereira I, Fernandes L. Base Excision Repair AP-Endonucleases-Like Genes Modulate DNA Damage Response and Virulence of the Human Pathogen Cryptococcus neoformans. J Fungi (Basel) 2021; 7:jof7020133. [PMID: 33673204 PMCID: PMC7917787 DOI: 10.3390/jof7020133] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/29/2021] [Accepted: 02/05/2021] [Indexed: 11/16/2022] Open
Abstract
Pathogenic microbes are exposed to a number of potential DNA-damaging stimuli during interaction with the host immune system. Microbial survival in this situation depends on a fine balance between the maintenance of DNA integrity and the adaptability provided by mutations. In this study, we investigated the association of the DNA repair response with the virulence of Cryptococcus neoformans, a basidiomycete that causes life-threatening meningoencephalitis in immunocompromised individuals. We focused on the characterization of C. neoformansAPN1 and APN2 putative genes, aiming to evaluate a possible role of the predicted Apurinic/apyrimidinic (AP) endonucleases 1 and 2 of the base excision repair (BER) pathway on C. neoformans response to stress conditions and virulence. Our results demonstrated the involvement of the putative AP-endonucleases Apn1 and Apn2 in the cellular response to DNA damage induced by alkylation and by UV radiation, in melanin production, in tolerance to drugs and in virulence of C. neoformans in vivo. We also pointed out the potential use of DNA repair inhibitor methoxy-amine in combination with conventional antifungal drugs, for the development of new therapeutic approaches against this human fungal pathogen. This work provides new information about the DNA damage response of the highly important pathogenic fungus C. neoformans.
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Affiliation(s)
- Rayssa Karla de Medeiros Oliveira
- Department of Cell Biology, Institute of Biological Sciences, University of Brasília, Brasília 70.910-900, Brazil; (R.K.d.M.O.); (F.A.H.); (P.H.G.); (L.L.P.)
| | - Fabián Andrés Hurtado
- Department of Cell Biology, Institute of Biological Sciences, University of Brasília, Brasília 70.910-900, Brazil; (R.K.d.M.O.); (F.A.H.); (P.H.G.); (L.L.P.)
| | - Pedro Henrique Gomes
- Department of Cell Biology, Institute of Biological Sciences, University of Brasília, Brasília 70.910-900, Brazil; (R.K.d.M.O.); (F.A.H.); (P.H.G.); (L.L.P.)
| | - Luiza Lassi Puglia
- Department of Cell Biology, Institute of Biological Sciences, University of Brasília, Brasília 70.910-900, Brazil; (R.K.d.M.O.); (F.A.H.); (P.H.G.); (L.L.P.)
| | - Fernanda Fonsêca Ferreira
- Department of Genetics and Morphology, Institute of Biological Sciences, University of Brasília, Brasília 70.910-900, Brazil; (F.F.F.); (K.R.)
| | - Kunal Ranjan
- Department of Genetics and Morphology, Institute of Biological Sciences, University of Brasília, Brasília 70.910-900, Brazil; (F.F.F.); (K.R.)
| | | | - Márcio José Poças-Fonseca
- Department of Genetics and Morphology, Institute of Biological Sciences, University of Brasília, Brasília 70.910-900, Brazil; (F.F.F.); (K.R.)
- Correspondence: (M.J.P.-F.); (I.S.-P.); (L.F.)
| | - Ildinete Silva-Pereira
- Department of Cell Biology, Institute of Biological Sciences, University of Brasília, Brasília 70.910-900, Brazil; (R.K.d.M.O.); (F.A.H.); (P.H.G.); (L.L.P.)
- Correspondence: (M.J.P.-F.); (I.S.-P.); (L.F.)
| | - Larissa Fernandes
- Faculty of Ceilândia, University of Brasília, Brasília 72.220-275, Brazil;
- Correspondence: (M.J.P.-F.); (I.S.-P.); (L.F.)
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Alanio A. Dormancy in Cryptococcus neoformans: 60 years of accumulating evidence. J Clin Invest 2021; 130:3353-3360. [PMID: 32484459 DOI: 10.1172/jci136223] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Cryptococcus neoformans is an opportunistic yeast that is present worldwide and interacts with various organisms. In humans, it is responsible for cryptococcosis, a deadly invasive fungal infection that represents around 220,000 cases per year worldwide. Starting from the natural history of the disease in humans, there is accumulating evidence on the capacity of this organism to enter dormancy. In response to the harsh host environment, the yeast is able to adapt dramatically and escape the vigilance of the host's immune cells to survive. Indeed, the yeast exposed to the host takes on pleiotropic phenotypes, enabling the generation of populations in heterogeneous states, including dormancy, to eventually survive at low metabolic cost and revive in favorable conditions. The concept of dormancy has been validated in C. neoformans from both epidemiological and genotyping data, and more recently from the biological point of view with the characterization of dormancy through the description of viable but nonculturable cells.
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Affiliation(s)
- Alexandre Alanio
- Laboratoire de Parasitologie-Mycologie, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France.,Molecular Mycology Unit, CNRS UMR 2000, National Reference Center for Invasive Mycoses and Antifungals (NRCMA), Institut Pasteur, Paris, France.,Université de Paris, Paris, France
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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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Zhang L, Zhang K, Fang W, Li H, Li Y, Jiang W, Hu D, Coelho C, Liu X, Cai L, Liao W, Pan W. CircRNA-1806 Decreases T Cell Apoptosis and Prolongs Survival of Mice After Cryptococcal Infection by Sponging miRNA-126. Front Microbiol 2020; 11:596440. [PMID: 33281794 PMCID: PMC7691421 DOI: 10.3389/fmicb.2020.596440] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 10/21/2020] [Indexed: 01/10/2023] Open
Abstract
CircRNAs are a recently well-known regulator that mediates a variety of biological processes. Cryptococcus neoformans is an environmental fungal pathogen that can cause fatal cryptococcal meningitis in immunocompromised individuals. However, the involvement of circRNA in cryptococcal infection remains unclear. In this study, high-throughput microarray was performed to identify the circRNA expression profile in cryptococcal meningitis patients. Circ_0001806 was significantly decreased in cryptococcal meningitis individuals. Then the effects of circ_0001806 and its interaction with miRNAs were explored in vivo and in vitro. The knock-down of circ_0001806 led to higher fungal infection and shorter survival in an experimental murine cryptococcosis model. Transcriptome analysis showed that decreased circ_0001806 regulated pathways related to the host antimicrobe response in T cells. Furthermore, in vitro experiments showed that circ_0001806 positively modulates ADM level, decreasing cell apoptosis and G1S arrest in T cells. Finally, we found circ_0001806 exerted its effects by sponging miRNA-126 in T cells. Taken together, our results reveal the role of circRNA-1806/miRNA-126 in the regulation of cell cycle and apoptosis in cryptococcal infection and can provide a new insights of the pathogenesis of cryptococcal infection.
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Affiliation(s)
- Lei Zhang
- Department of Dermatology and Venereology, Changzheng Hospital, Second Military Medical University, Shanghai, China.,Shanghai Key Laboratory of Molecular Medical Mycology, Shanghai Institute of Medical Mycology, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Keming Zhang
- Department of Dermatology and Venereology, Changzheng Hospital, Second Military Medical University, Shanghai, China.,Shanghai Key Laboratory of Molecular Medical Mycology, Shanghai Institute of Medical Mycology, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Wenjie Fang
- Department of Dermatology and Venereology, Changzheng Hospital, Second Military Medical University, Shanghai, China.,Shanghai Key Laboratory of Molecular Medical Mycology, Shanghai Institute of Medical Mycology, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Hang Li
- Department of Dermatology and Venereology, Changzheng Hospital, Second Military Medical University, Shanghai, China.,Shanghai Key Laboratory of Molecular Medical Mycology, Shanghai Institute of Medical Mycology, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Yingfang Li
- Department of Dermatology and Venereology, Changzheng Hospital, Second Military Medical University, Shanghai, China.,Shanghai Key Laboratory of Molecular Medical Mycology, Shanghai Institute of Medical Mycology, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Weiwei Jiang
- Department of Dermatology and Venereology, Changzheng Hospital, Second Military Medical University, Shanghai, China.,Shanghai Key Laboratory of Molecular Medical Mycology, Shanghai Institute of Medical Mycology, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Dongying Hu
- Department of Dermatology and Venereology, Changzheng Hospital, Second Military Medical University, Shanghai, China.,Shanghai Key Laboratory of Molecular Medical Mycology, Shanghai Institute of Medical Mycology, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Carolina Coelho
- MRC Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | - Xiaogang Liu
- Department of Dermatology and Venereology, Changzheng Hospital, Second Military Medical University, Shanghai, China.,Shanghai Key Laboratory of Molecular Medical Mycology, Shanghai Institute of Medical Mycology, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Liangqi Cai
- Department of Dermatology, The First Affiliated Hospital of Xiamen University, Fujian, China
| | - Wanqing Liao
- Department of Dermatology and Venereology, Changzheng Hospital, Second Military Medical University, Shanghai, China.,Shanghai Key Laboratory of Molecular Medical Mycology, Shanghai Institute of Medical Mycology, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Weihua Pan
- Department of Dermatology and Venereology, Changzheng Hospital, Second Military Medical University, Shanghai, China.,Shanghai Key Laboratory of Molecular Medical Mycology, Shanghai Institute of Medical Mycology, Changzheng Hospital, Second Military Medical University, Shanghai, China
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Kannambath S, Jarvis JN, Wake RM, Longley N, Loyse A, Matzaraki V, Aguirre-Gamboa R, Wijmenga C, Doyle R, Paximadis M, Tiemessen CT, Kumar V, Pittman A, Meintjes G, Harrison TS, Netea MG, Bicanic T. Genome-Wide Association Study Identifies Novel Colony Stimulating Factor 1 Locus Conferring Susceptibility to Cryptococcosis in Human Immunodeficiency Virus-Infected South Africans. Open Forum Infect Dis 2020; 7:ofaa489. [PMID: 33269293 PMCID: PMC7686661 DOI: 10.1093/ofid/ofaa489] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 10/12/2020] [Indexed: 12/31/2022] Open
Abstract
Background Cryptococcus is the most common cause of meningitis in human immunodeficiency virus (HIV)-infected Africans. Despite universal exposure, only 5%-10% of patients with HIV/acquired immune deficiency syndrome and profound CD4+ T-cell depletion develop disseminated cryptococcosis: host genetic factors may play a role. Prior targeted immunogenetic studies in cryptococcosis have comprised few Africans. Methods We analyzed genome-wide single-nucleotide polymorphism (SNP) genotype data from 524 patients of African descent: 243 cases (advanced HIV with cryptococcal antigenemia and/or cryptococcal meningitis) and 281 controls (advanced HIV, no history of cryptococcosis, negative serum cryptococcal antigen). Results Six loci upstream of the colony-stimulating factor 1 (CSF1) gene, encoding macrophage colony-stimulating factor (M-CSF) were associated with susceptibility to cryptococcosis at P < 10-6 and remained significantly associated in a second South African cohort (83 cases; 128 controls). Meta-analysis of the genotyped CSF1 SNP rs1999713 showed an odds ratio for cryptococcosis susceptibility of 0.53 (95% confidence interval, 0.42-0.66; P = 5.96 × 10-8). Ex vivo functional validation and transcriptomic studies confirmed the importance of macrophage activation by M-CSF in host defence against Cryptococcus in HIV-infected patients and healthy, ethnically matched controls. Conclusions This first genome-wide association study of susceptibility to cryptococcosis has identified novel and immunologically relevant susceptibility loci, which may help define novel strategies for prevention or immunotherapy of HIV-associated cryptococcal meningitis.
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Affiliation(s)
- Shichina Kannambath
- Institute of Infection and Immunity, St George's University of London, London, United Kingdom.,National Institute of Health Research Biomedical Research Centre at Guy's and St Thomas' Hospital and King's College London, London, United Kingdom
| | - Joseph N Jarvis
- Department of Clinical Research, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom.,Botswana Harvard AIDS Institute Partnership, Gaborone, Botswana
| | - Rachel M Wake
- Institute of Infection and Immunity, St George's University of London, London, United Kingdom.,Clinical Academic Group in Infection, St George's Hospital NHS Trust, London, United Kingdom
| | - Nicky Longley
- Institute of Infection and Immunity, St George's University of London, London, United Kingdom
| | - Angela Loyse
- Institute of Infection and Immunity, St George's University of London, London, United Kingdom
| | - Vicky Matzaraki
- University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, the Netherlands
| | - Raúl Aguirre-Gamboa
- University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, the Netherlands
| | - Cisca Wijmenga
- University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, the Netherlands
| | - Ronan Doyle
- Department of Clinical Research, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Maria Paximadis
- Centre for HIV and STIs, National Institute for Communicable Diseases and Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Caroline T Tiemessen
- Centre for HIV and STIs, National Institute for Communicable Diseases and Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Vinod Kumar
- University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, the Netherlands.,Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University, Nijmegen, the Netherlands
| | - Alan Pittman
- Institute of Infection and Immunity, St George's University of London, London, United Kingdom
| | - Graeme Meintjes
- Department of Medicine and Wellcome Centre for Infectious Diseases Research in Africa, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Thomas S Harrison
- Institute of Infection and Immunity, St George's University of London, London, United Kingdom.,Clinical Academic Group in Infection, St George's Hospital NHS Trust, London, United Kingdom.,Department of Medicine and Wellcome Centre for Infectious Diseases Research in Africa, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Mihai G Netea
- Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University, Nijmegen, the Netherlands.,Department for Genomics & Immunoregulation, Life and Medical Sciences Institute (LIMES), University of Bonn, Bonn, Germany
| | - Tihana Bicanic
- Institute of Infection and Immunity, St George's University of London, London, United Kingdom.,Clinical Academic Group in Infection, St George's Hospital NHS Trust, London, United Kingdom
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Okurut S, Boulware DR, Olobo J, Meya DB. Landmark clinical observations and immunopathogenesis pathways linked to HIV and Cryptococcus fatal central nervous system co-infection. Mycoses 2020; 63:840-853. [PMID: 32472727 PMCID: PMC7416908 DOI: 10.1111/myc.13122] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 05/21/2020] [Accepted: 05/22/2020] [Indexed: 12/13/2022]
Abstract
Cryptococcal meningitis remains one of the leading causes of death among HIV-infected adults in the fourth decade of HIV era in sub-Saharan Africa, contributing to 10%-20% of global HIV-related deaths. Despite widespread use and early induction of ART among HIV-infected adults, incidence of cryptococcosis remains significant in those with advanced HIV disease. Cryptococcus species that causes fatal infection follows systemic spread from initial environmental acquired infection in lungs to antigenaemia and fungaemia in circulation prior to establishment of often fatal disease, cryptococcal meningitis in the CNS. Cryptococcus person-to-person transmission is uncommon, and deaths related to blood infection without CNS involvement are rare. Keen to the persistent high mortality associated with HIV-cryptococcal meningitis, seizures are common among a third of the patients, altered mental status is frequent, anaemia is prevalent with ensuing brain hypoxia and at autopsy, brain fibrosis and infarction are evident. In addition, fungal burden is 3-to-4-fold higher in those with seizures. And high immune activation together with exacerbated inflammation and elevated PD-1/PD-L immune checkpoint expression is immunomodulated phenotypes elevated in CSF relative to blood. Lastly, though multiple Cryptococcus species cause disease in this setting, observations are mostly generalised to cryptococcal infection/meningitis or regional dominant species (C neoformans or gattii complex) that may limit our understanding of interspecies differences in infection, progression, treatment or recovery outcome. Together, these factors and underlying mechanisms are hypotheses generating for research to find targets to prevent infection or adequate therapy to prevent persistent high mortality with current optimal therapy.
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Affiliation(s)
- Samuel Okurut
- Research DepartmentInfectious Diseases InstituteMakerere UniversityKampalaUganda
- Department of MicrobiologySchool of Biomedical SciencesCollege of Health SciencesMakerere UniversityKampalaUganda
| | - David R. Boulware
- Division of Infectious Diseases and International MedicineDepartment of MedicineUniversity of MinnesotaMinneapolisMinnesota
| | - Joseph Olobo
- Department of Immunology and Molecular BiologySchool of Biomedical SciencesCollege of Health SciencesMakerere UniversityKampalaUganda
| | - David B. Meya
- Research DepartmentInfectious Diseases InstituteMakerere UniversityKampalaUganda
- Division of Infectious Diseases and International MedicineDepartment of MedicineUniversity of MinnesotaMinneapolisMinnesota
- Department of MedicineSchool of MedicineCollege of Health SciencesMakerere UniversityKampalaUganda
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Fenbendazole Controls In Vitro Growth, Virulence Potential, and Animal Infection in the Cryptococcus Model. Antimicrob Agents Chemother 2020; 64:AAC.00286-20. [PMID: 32253211 DOI: 10.1128/aac.00286-20] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 03/29/2020] [Indexed: 12/17/2022] Open
Abstract
The human diseases caused by the fungal pathogens Cryptococcus neoformans and Cryptococcus gattii are associated with high indices of mortality and toxic and/or cost-prohibitive therapeutic protocols. The need for affordable antifungals to combat cryptococcal disease is unquestionable. Previous studies suggested benzimidazoles as promising anticryptococcal agents combining low cost and high antifungal efficacy, but their therapeutic potential has not been demonstrated so far. In this study, we investigated the antifungal potential of fenbendazole, the most effective anticryptococcal benzimidazole. Fenbendazole was inhibitory against 17 different isolates of C. neoformans and C. gattii at a low concentration. The mechanism of anticryptococcal activity of fenbendazole involved microtubule disorganization, as previously described for human parasites. In combination with fenbendazole, the concentrations of the standard antifungal amphotericin B required to control cryptococcal growth were lower than those required when this antifungal was used alone. Fenbendazole was not toxic to mammalian cells. During macrophage infection, the anticryptococcal effects of fenbendazole included inhibition of intracellular proliferation rates and reduced phagocytic escape through vomocytosis. Fenbendazole deeply affected the cryptococcal capsule. In a mouse model of cryptococcosis, the efficacy of fenbendazole to control animal mortality was similar to that observed for amphotericin B. These results indicate that fenbendazole is a promising candidate for the future development of an efficient and affordable therapeutic tool to combat cryptococcosis.
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Beattie SR, Schnicker NJ, Murante T, Kettimuthu K, Williams NS, Gakhar L, Krysan DJ. Benzothiourea Derivatives Target the Secretory Pathway of the Human Fungal Pathogen Cryptococcus neoformans. ACS Infect Dis 2020; 6:529-539. [PMID: 32070095 DOI: 10.1021/acsinfecdis.9b00478] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Cryptococcus neoformans is one of the most important human fungal pathogens and causes life-threatening meningoencephalitis in immunocompromised patients. The current gold standard therapy for C. neoformans meningoencephalitis is based on medications that are over 50 years old and is not readily available in regions with high disease burden. Here, we report the mycologic, mechanistic, and pharmacologic characterization of a set of benzothioureas with highly selective fungicidal activity against C. neoformans. In addition, to direct antifungal activity, benzothioureas inhibit C. neoformans virulence traits. On the basis of a set of phenotypic, biochemical, and biophysical assays, the benzothioureas (BTUs) inhibit the late secretory pathway (post-Golgi), possibly through a direct interaction with Sav1, an orthologue of the Sec4-class small GTPase. Importantly, pharmacological characterization of the BTUs indicates it readily penetrates the blood-brain barrier. Together, our data support the further development of this scaffold as an antifungal agent with a novel mechanism of action against C. neoformans.
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Affiliation(s)
- Sarah R. Beattie
- Department of Pediatrics, Carver College of Medicine, University of Iowa, 25 South Grand Avenue, Iowa City, Iowa 52245, United States
| | - Nicholas J. Schnicker
- Protein and Crystallography Facility, Carver College of Medicine, University of Iowa, 51 Newton Road, Iowa City, Iowa 52245, United States
| | - Thomas Murante
- Department of Pediatrics, University of Rochester, 601 Elmwood Avenue, Rochester, New York 14642, United States
| | - Kavitha Kettimuthu
- Department of Biochemistry, University of Texas Southwestern, 5323 Harry Hines Boulevard, Dallas, Texas 75390, United States
| | - Noelle S. Williams
- Department of Biochemistry, University of Texas Southwestern, 5323 Harry Hines Boulevard, Dallas, Texas 75390, United States
| | - Lokesh Gakhar
- Protein and Crystallography Facility, Carver College of Medicine, University of Iowa, 51 Newton Road, Iowa City, Iowa 52245, United States
- Department of Biochemistry, Carver College of Medicine, University of Iowa, 51 Newton Road, Iowa City, Iowa 52245, United States
| | - Damian J. Krysan
- Department of Pediatrics, Carver College of Medicine, University of Iowa, 25 South Grand Avenue, Iowa City, Iowa 52245, United States
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, 25 South Grand Avenue, Iowa City, Iowa 52245, United States
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Contribution of Laccase Expression to Immune Response against Cryptococcus gattii Infection. Infect Immun 2020; 88:IAI.00712-19. [PMID: 31871099 DOI: 10.1128/iai.00712-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 12/20/2019] [Indexed: 12/26/2022] Open
Abstract
Cryptococcosis is an infectious disease caused by two fungal species, Cryptococcus neoformans and Cryptococcus gattii While C. neoformans affects mainly immunocompromised patients, C. gattii infects both immunocompetent and immunocompromised individuals. Laccase is an important virulence factor that contributes to the virulence of C. neoformans by promoting pulmonary growth and dissemination to the brain. The presence of laccase in C. neoformans can shift the host immune response toward a nonprotective Th2-type response. However, the role of laccase in the immune response against C. gattii remains unclear. In this study, we characterized laccase activity in C. neoformans and C. gattii isolates from Thailand and investigated whether C. gattii that is deficient in laccase might modulate immune responses during infection. C. gattii was found to have higher laccase activity than C. neoformans, indicating the importance of laccase in the pathogenesis of C. gattii infection. The expression of laccase promoted intracellular proliferation in macrophages and inhibited in vitro fungal clearance. Mice infected with a lac1Δ mutant strain of C. gattii had reduced lung burdens at the early but not the late stage of infection. Without affecting type-1 and type-2 responses, the deficiency of laccase in C. gattii induced cryptococcus-specific interleukin-17 (IL-17) cytokine, neutrophil accumulation, and expression of the neutrophil-associated cytokine gene Csf3 and chemokine genes Cxcl1, Cxcl2, and Cxcl5 in vivo, as well as enhanced neutrophil-mediated phagocytosis and killing in vitro Thus, our data suggest that laccase constitutes an important virulence factor of C. gattii that plays roles in attenuating Th17-type immunity, neutrophil recruitment, and function during the early stage of infection.
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Nelson BN, Hawkins AN, Wozniak KL. Pulmonary Macrophage and Dendritic Cell Responses to Cryptococcus neoformans. Front Cell Infect Microbiol 2020; 10:37. [PMID: 32117810 PMCID: PMC7026008 DOI: 10.3389/fcimb.2020.00037] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 01/20/2020] [Indexed: 12/12/2022] Open
Abstract
The fungal pathogen Cryptococcus neoformans can cause life-threatening infections in immune compromised individuals. This pathogen is typically acquired via inhalation, and enters the respiratory tract. Innate immune cells such as macrophages and dendritic cells (DCs) are the first host cells that encounter C. neoformans, and the interactions between Cryptococcus and innate immune cells play a critical role in the progression of disease. Cryptococcus possesses several virulence factors and evasion strategies to prevent its killing and destruction by pulmonary phagocytes, but these phagocytic cells can also contribute to anti-cryptococcal responses. This review will focus on the interactions between Cryptococcus and primary macrophages and dendritic cells (DCs), dealing specifically with the cryptococcal/pulmonary cell interface.
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Affiliation(s)
- Benjamin N Nelson
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, United States
| | - Ashlee N Hawkins
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, United States
| | - Karen L Wozniak
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, United States
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42
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Evans RJ, Johnston SA. PPAR-gamma Fun(gi) With Prostaglandin. NUCLEAR RECEPTOR SIGNALING 2020; 17:1550762919899641. [PMID: 35582457 PMCID: PMC9109145 DOI: 10.1177/1550762919899641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 12/11/2019] [Indexed: 11/16/2022]
Abstract
In our recent publication, we show for the first time that the fungal pathogen Cryptococcus neoformans is able to manipulate host cells by producing eicosanoids that mimic those found in the host. Using complementary in vivo zebrafish and in vitro macrophage cell culture models of Cryptococcus infection, we found that these eicosanoids manipulate host innate immune cells by activating the host receptor PPAR-gamma which is an important regulator of macrophage inflammatory phenotypes. We initially identified PGE2 as the eicosanoid species responsible for this effect; however, we later found that a derivative of PGE2—15-keto-PGE2—was ultimately responsible and that this eicosanoid acted as a partial agonist to PPAR-gamma. In this commentary, we will discuss some of the concepts and conclusions in our original publication and expand on their implications and future directions.
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Rudman J, Evans RJ, Johnston SA. Are macrophages the heroes or villains during cryptococcosis? Fungal Genet Biol 2019; 132:103261. [DOI: 10.1016/j.fgb.2019.103261] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 08/06/2019] [Accepted: 08/06/2019] [Indexed: 10/26/2022]
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44
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Polysaccharide diversity in VNI isolates of Cryptococcus neoformans from Roraima, Northern Brazil. Fungal Biol 2019; 123:699-708. [DOI: 10.1016/j.funbio.2019.06.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 06/03/2019] [Accepted: 06/03/2019] [Indexed: 02/03/2023]
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The Role of Melanin in Fungal Pathogenesis for Animal Hosts. Curr Top Microbiol Immunol 2019; 422:1-30. [PMID: 31278515 DOI: 10.1007/82_2019_173] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Melanins are a class of pigments that are ubiquitous throughout biology. They play incredibly diverse and important roles ranging from radiation protection to immune defense, camouflage, and virulence. Fungi have evolved to use melanin to be able to persist in the environment and within organisms. Fungal melanins are often located within the cell well and are able to neutralize reactive oxygen species and other radicals, defend against UV radiation, bind and sequester non-specific peptides and compounds, and produce a physical barrier that defends the cell. For this reason, melanized fungi are often well-suited to be human pathogens-melanin allows fungi to neutralize the microbicidal oxidative bursts of our innate immune system, bind and inactivate to antimicrobial peptides and enzymes, sequester antifungal pharmaceuticals, and create a shield to block immune recognition of the fungus. Due to the importance and pervasiveness of melanin in fungal virulence, mammalian immune systems have evolved antifungal strategies that involve directly detecting and binding to fungal melanins. Such strategies include the use of melanin-specific antibody responses and C-type lectins like the newly discovered melanin-specific MelLec receptor.
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46
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Gerstein AC, Jackson KM, McDonald TR, Wang Y, Lueck BD, Bohjanen S, Smith KD, Akampurira A, Meya DB, Xue C, Boulware DR, Nielsen K. Identification of Pathogen Genomic Differences That Impact Human Immune Response and Disease during Cryptococcus neoformans Infection. mBio 2019; 10:e01440-19. [PMID: 31311883 PMCID: PMC6635531 DOI: 10.1128/mbio.01440-19] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 06/10/2019] [Indexed: 12/18/2022] Open
Abstract
Patient outcomes during infection are due to a complex interplay between the quality of medical care, host immunity factors, and the infecting pathogen's characteristics. To probe the influence of pathogen genotype on human survival, immune response, and other parameters of disease, we examined Cryptococcus neoformans isolates collected during the Cryptococcal Optimal Antiretroviral Therapy (ART) Timing (COAT) Trial in Uganda. We measured human participants' survival, meningitis disease parameters, immunologic phenotypes, and pathogen in vitro growth characteristics. We compared those clinical data to whole-genome sequences from 38 C. neoformans isolates of the most frequently observed sequence type (ST), ST93, in our Ugandan participant population and to sequences from an additional 18 strains of 9 other sequence types representing the known genetic diversity within the Ugandan Cryptococcus clinical isolates. We focused our analyses on 652 polymorphisms that were variable among the ST93 genomes, were not in centromeres or extreme telomeres, and were predicted to have a fitness effect. Logistic regression and principal component analysis identified 40 candidate Cryptococcus genes and 3 hypothetical RNAs associated with human survival, immunologic response, or clinical parameters. We infected mice with 17 available KN99α gene deletion strains for these candidate genes and found that 35% (6/17) directly influenced murine survival. Four of the six gene deletions that impacted murine survival were novel. Such bedside-to-bench translational research identifies important candidate genes for future studies on virulence-associated traits in human Cryptococcus infections.IMPORTANCE Even with the best available care, mortality rates in cryptococcal meningitis range from 20% to 60%. Disease is often due to infection by the fungus Cryptococcus neoformans and involves a complex interaction between the human host and the fungal pathogen. Although previous studies have suggested genetic differences in the pathogen impact human disease, it has proven quite difficult to identify the specific C. neoformans genes that impact the outcome of the human infection. Here, we take advantage of a Ugandan patient cohort infected with closely related C. neoformans strains to examine the role of pathogen genetic variants on several human disease characteristics. Using a pathogen whole-genome sequencing approach, we showed that 40 C. neoformans genes are associated with human disease. Surprisingly, many of these genes are specific to Cryptococcus and have unknown functions. We also show deletion of some of these genes alters disease in a mouse model of infection, confirming their role in disease. These findings are particularly important because they are the first to identify C. neoformans genes associated with human cryptococcal meningitis and lay the foundation for future studies that may lead to new treatment strategies aimed at reducing patient mortality.
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Affiliation(s)
- Aleeza C Gerstein
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Katrina M Jackson
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Tami R McDonald
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Yina Wang
- Public Health Research Institute, Rutgers University, Newark, New Jersey, USA
| | - Benjamin D Lueck
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Sara Bohjanen
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Kyle D Smith
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Andrew Akampurira
- Infectious Diseases Institute and School of Medicine, College of Health Sciences, Makerere University, Kampala, Uganda
| | - David B Meya
- Infectious Diseases Institute and School of Medicine, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Chaoyang Xue
- Public Health Research Institute, Rutgers University, Newark, New Jersey, USA
| | - David R Boulware
- Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Kirsten Nielsen
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota, USA
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The Mouse Inhalation Model of Cryptococcus neoformans Infection Recapitulates Strain Virulence in Humans and Shows that Closely Related Strains Can Possess Differential Virulence. Infect Immun 2019; 87:IAI.00046-19. [PMID: 30833336 DOI: 10.1128/iai.00046-19] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 02/22/2019] [Indexed: 12/30/2022] Open
Abstract
Cryptococcal meningitis (CM) causes high rates of HIV-related mortality, yet the Cryptococcus factors influencing patient outcome are not well understood. Pathogen-specific traits, such as the strain genotype and degree of antigen shedding, are associated with the clinical outcome, but the underlying biology remains elusive. In this study, we examined factors determining disease outcome in HIV-infected cryptococcal meningitis patients infected with Cryptococcus neoformans strains with the same multilocus sequence type (MLST). Both patient mortality and survival were observed during infections with the same sequence type. Disease outcome was not associated with the patient CD4 count. Patient mortality was associated with higher cryptococcal antigen levels, the cerebrospinal fluid (CSF) fungal burden by quantitative culture, and low CSF fungal clearance. The virulence of a subset of clinical strains with the same sequence type was analyzed using a mouse inhalation model of cryptococcosis. We showed a strong association between human and mouse mortality rates, demonstrating that the mouse inhalation model recapitulates human infection. Similar to human infection, the ability to multiply in vivo, demonstrated by a high fungal burden in lung and brain tissues, was associated with mouse mortality. Mouse survival time was not associated with single C. neoformans virulence factors in vitro or in vivo; rather, a trend in survival time correlated with a suite of traits. These observations show that MLST-derived genotype similarities between C. neoformans strains do not necessarily translate into similar virulence either in the mouse model or in human patients. In addition, our results show that in vitro assays do not fully reproduce in vivo conditions that influence C. neoformans virulence.
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Hansakon A, Mutthakalin P, Ngamskulrungroj P, Chayakulkeeree M, Angkasekwinai P. Cryptococcus neoformans and Cryptococcus gattii clinical isolates from Thailand display diverse phenotypic interactions with macrophages. Virulence 2019; 10:26-36. [PMID: 30520685 PMCID: PMC6298761 DOI: 10.1080/21505594.2018.1556150] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Cryptococcus-macrophage interaction is crucial in the development of cryptococcocal diseases. C. neoformans and C. gattii are major pathogenic species that occupy different niches and cause different clinical manifestations. However, the differences of macrophage interaction among these species in affecting different disease outcomes and immune responses have not been clearly addressed. Here, we examined the macrophage uptake rates, intracellular loads and intracellular proliferation rates of C. neoformans and C. gattii clinical isolates from Thailand and analyzed the effect of those interactions on fungal burdens and host immune responses. C. neoformans isolates showed a higher phagocytosis rate but lower intracellular proliferation rate than C. gattii. Indeed, the high intracellular proliferation rate of C. gattii isolates did not influence the fungal burdens in lungs and brains of infected mice, whereas infection with high-uptake C. neoformans isolates resulted in significantly higher brain burdens that associated with reduced survival rate. Interestingly, alveolar macrophages of mice infected with high-uptake C. neoformans isolates showed distinct patterns of alternatively activated macrophage (M2) gene expressions with higher Arg1, Fizz1, Il13 and lower Nos2, Ifng, Il6, Tnfa, Mcp1, csf2 and Ip10 transcripts. Corresponding to this finding, infection with high-uptake C. neoformans resulted in enhanced arginase enzyme activity, elevated IL-4 and IL-13 and lowered IL-17 in the bronchoalveolar lavage. Thus, our data suggest that the macrophage interaction with C. neoformans and C. gattii may affect different disease outcomes and the high phagocytosis rates of C. neoformans influence the induction of type-2 immune responses that support fungal dissemination and disease progression. Abbreviation: Arg1: Arginase 1; BAL: Bronchoalveolar lavage; CCL17: Chemokine (C-C motif) ligand 17; CNS: Central nervous system; CSF: Cerebrospinal fluid; Csf2: Colony-stimulating factor 2; Fizz1: Found in inflammatory zone 1; HIV: Human immunodeficiency virus; ICL: Intracellular cryptococcal load; Ifng: Interferon gamma; Ip10: IFN-g-inducible protein 10; IPR: Intracellular proliferation rate; Mcp1: Monocyte chemoattractant protein 1; Nos2: Nitric oxide synthase 2; PBS: Phosphate-Buffered Saline; Th: T helper cell; Tnfa: Tumor necrosis factor alpha.
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Affiliation(s)
- Adithap Hansakon
- a Department of Medical Technology, Faculty of Allied Health Sciences , Thammasat University , Pathumthani , Thailand.,b Graduate Program in Biomedical Science, Faculty of Allied Health Sciences , Thammasat University , Pathumthani , Thailand
| | - Putthiphak Mutthakalin
- a Department of Medical Technology, Faculty of Allied Health Sciences , Thammasat University , Pathumthani , Thailand
| | - Popchai Ngamskulrungroj
- c Department of Microbiology, Faculty of Medicine, Siriraj Hospital , Mahidol University , Bangkok , Thailand
| | - Methee Chayakulkeeree
- d Division of Infectious Diseases and Tropical Medicine, Department of Medicine, Faculty of Medicine Siriraj Hospital , Mahidol University , Bangkok , Thailand
| | - Pornpimon Angkasekwinai
- a Department of Medical Technology, Faculty of Allied Health Sciences , Thammasat University , Pathumthani , Thailand.,b Graduate Program in Biomedical Science, Faculty of Allied Health Sciences , Thammasat University , Pathumthani , Thailand
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Winter N, Rupcic Z, Stadler M, Trauner D. Synthesis and biological evaluation of (±)-hippolachnin and analogs. J Antibiot (Tokyo) 2019; 72:375-383. [DOI: 10.1038/s41429-019-0176-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 01/12/2019] [Indexed: 01/23/2023]
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Heung LJ, Hohl TM. Inflammatory monocytes are detrimental to the host immune response during acute infection with Cryptococcus neoformans. PLoS Pathog 2019; 15:e1007627. [PMID: 30897162 PMCID: PMC6428256 DOI: 10.1371/journal.ppat.1007627] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 02/07/2019] [Indexed: 12/30/2022] Open
Abstract
Cryptococcus neoformans is a leading cause of invasive fungal infections among immunocompromised patients. However, the cellular constituents of the innate immune response that promote clearance versus progression of infection upon respiratory acquisition of C. neoformans remain poorly defined. In this study, we found that during acute C. neoformans infection, CCR2+ Ly6Chi inflammatory monocytes (IM) rapidly infiltrate the lungs and mediate fungal trafficking to lung-draining lymph nodes. Interestingly, this influx of IM is detrimental to the host, since ablating IM or impairing their recruitment to the lungs improves murine survival and reduces fungal proliferation and dissemination. Using a novel conditional gene deletion strategy, we determined that MHC class II expression by IM did not mediate their deleterious impact on the host. Furthermore, although ablation of IM reduced the number of lymphocytes, innate lymphoid cells, and eosinophils in the lungs, the effects of IM were not dependent on these cells. We ascertained that IM in the lungs upregulated transcripts associated with alternatively activated (M2) macrophages in response to C. neoformans, consistent with the model that IM assume a cellular phenotype that is permissive for fungal growth. We also determined that conditional knockout of the prototypical M2 marker arginase 1 in IM and deletion of the M2-associated transcription factor STAT6 were not sufficient to reverse the harmful effects of IM. Overall, our findings indicate that C. neoformans can subvert the fungicidal potential of IM to enable the progression of infection through a mechanism that is not dependent on lymphocyte priming, eosinophil recruitment, or downstream M2 macrophage polarization pathways. These results give us new insight into the plasticity of IM function during fungal infections and the level of control that C. neoformans can exert on host immune responses. Cryptococcus neoformans is a fungus that is prevalent throughout the environment and can cause a fatal infection of the central nervous system when inhaled into the lungs by patients with impaired immune systems. Our understanding of the immune responses that either help clear C. neoformans from the lungs or permit development of disease remains limited. In this study, we used a mouse model of lethal C. neoformans infection to determine that inflammatory monocytes, immune cells that are often among the first responders to infections, actually facilitate the progression of infection rather than clearance. These findings establish a foundation for future work to target the immune response of inflammatory monocytes as a strategy to improve the outcomes of patients that develop C. neoformans infections.
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Affiliation(s)
- Lena J. Heung
- Infectious Diseases Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York, United States of America
- * E-mail: (LJH); (TMH)
| | - Tobias M. Hohl
- Infectious Diseases Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York, United States of America
- Immunology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, New York, United States of America
- * E-mail: (LJH); (TMH)
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