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Melhem MSC, Leite Júnior DP, Takahashi JPF, Macioni MB, Oliveira LD, de Araújo LS, Fava WS, Bonfietti LX, Paniago AMM, Venturini J, Espinel-Ingroff A. Antifungal Resistance in Cryptococcal Infections. Pathogens 2024; 13:128. [PMID: 38392866 PMCID: PMC10891860 DOI: 10.3390/pathogens13020128] [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: 10/23/2023] [Revised: 01/20/2024] [Accepted: 01/22/2024] [Indexed: 02/25/2024] Open
Abstract
Antifungal therapy, especially with the azoles, could promote the incidence of less susceptible isolates of Cryptococcus neoformans and C. gattii species complexes (SC), mostly in developing countries. Given that these species affect mostly the immunocompromised host, the infections are severe and difficult to treat. This review encompasses the following topics: 1. infecting species and their virulence, 2. treatment, 3. antifungal susceptibility methods and available categorical endpoints, 4. genetic mechanisms of resistance, 5. clinical resistance, 6. fluconazole minimal inhibitory concentrations (MICs), clinical outcome, 7. environmental influences, and 8. the relevance of host factors, including pharmacokinetic/pharmacodynamic (PK/PD) parameters, in predicting the clinical outcome to therapy. As of now, epidemiologic cutoff endpoints (ECVs/ECOFFs) are the most reliable antifungal resistance detectors for these species, as only one clinical breakpoint (amphotericin B and C. neoformans VNI) is available.
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Affiliation(s)
- Marcia S C Melhem
- Graduate Program in Sciences, Secretary of Health, São Paulo 01246-002, SP, Brazil
- Graduate Program in Infectious and Parasitic Diseases, Federal University of Mato Grosso do Sul, Campo Grande 79070-900, MS, Brazil
- Graduate Program in Tropical Diseases, State University of São Paulo, Botucatu 18618-687, SP, Brazil
| | | | - Juliana P F Takahashi
- Graduate Program in Infectious and Parasitic Diseases, Federal University of Mato Grosso do Sul, Campo Grande 79070-900, MS, Brazil
- Pathology Division, Adolfo Lutz Institute, São Paulo 01246-002, SP, Brazil
| | | | | | - Lisandra Siufi de Araújo
- Graduate Program in Infectious and Parasitic Diseases, Federal University of Mato Grosso do Sul, Campo Grande 79070-900, MS, Brazil
- Central Public Health Laboratory-LACEN, Mycology Unit, Adolfo Lutz Institut, São Paulo 01246-002, SP, Brazil
| | - Wellington S Fava
- Graduate Program in Infectious and Parasitic Diseases, Federal University of Mato Grosso do Sul, Campo Grande 79070-900, MS, Brazil
| | - Lucas X Bonfietti
- Central Public Health Laboratory-LACEN, Mycology Unit, Adolfo Lutz Institut, São Paulo 01246-002, SP, Brazil
| | - Anamaria M M Paniago
- Graduate Program in Infectious and Parasitic Diseases, Federal University of Mato Grosso do Sul, Campo Grande 79070-900, MS, Brazil
| | - James Venturini
- Graduate Program in Infectious and Parasitic Diseases, Federal University of Mato Grosso do Sul, Campo Grande 79070-900, MS, Brazil
| | - Ana Espinel-Ingroff
- Central Public Health Laboratory-LACEN, Campo Grande 79074-460, MS, Brazil
- VCU Medical Center, Richmond, VA 23284, USA
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2
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Morovati H, Kord M, Ahmadikia K, Eslami S, Hemmatzadeh M, Kurdestani KM, Khademi M, Darabian S. A Comprehensive Review of Identification Methods for Pathogenic Yeasts: Challenges and Approaches. Adv Biomed Res 2023; 12:187. [PMID: 37694259 PMCID: PMC10492613 DOI: 10.4103/abr.abr_375_22] [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: 11/07/2022] [Revised: 03/04/2023] [Accepted: 03/06/2023] [Indexed: 09/12/2023] Open
Abstract
Given the increasing incidence of yeast infections and the presence of drug-resistant isolates, accurate identification of the pathogenic yeasts is essential for the management of yeast infections. In this review, we tried to introduce the routine and novel techniques applied for yeast identification. Laboratory identification methods of pathogenic yeast are classified into three categories; I. conventional methods, including microscopical and culture-base methods II. biochemical/physiological-processes methods III. molecular methods. While conventional and biochemical methods require more precautions and are not specific in some cases, molecular diagnostic methods are the optimum tools for diagnosing pathogenic yeasts in a short time with high accuracy and specificity, and having various methods that cover different purposes, and affordable costs for researchers. Nucleotide sequencing is a reference or gold standard for identifying pathogenic yeasts. Since it is an expensive method, it is not widely used in developing countries. However, novel identification techniques are constantly updated, and we recommend further studies in this field. The results of this study will guide researchers in finding more accurate diagnostic method(s) for their studies in a short period of time.
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Affiliation(s)
- Hamid Morovati
- Department of Parasitology and Mycology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohammad Kord
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Kazem Ahmadikia
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Saba Eslami
- Central Research Laboratory, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Masoumeh Hemmatzadeh
- Department of Mycology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Kian M. Kurdestani
- Department of Microbiology, Sanandaj Branch, Islamic Azad University, Sanandaj, Iran
| | | | - Sima Darabian
- Department of Medical Parasitology and Mycology, School of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran
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3
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Liu Y, Zhang Y, Zhao X, Lu W, Zhong Y, Fu YV. Antifungal Peptide SP1 Damages Polysaccharide Capsule of Cryptococcus neoformans and Enhances Phagocytosis of Macrophages. Microbiol Spectr 2023; 11:e0456222. [PMID: 36916981 PMCID: PMC10100895 DOI: 10.1128/spectrum.04562-22] [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: 11/08/2022] [Accepted: 02/22/2023] [Indexed: 03/16/2023] Open
Abstract
Cryptococcus neoformans is a fungal pathogen which causes nearly half a million deaths worldwide each year. Under host-relevant conditions, it produces a characteristic polysaccharide capsule. The polysaccharide capsule is one of the main virulence factors of C. neoformans, which involves antiphagocytosis and immune responses of the host to cause a lack of an immune. Meanwhile, the polysaccharide capsule is a promising drug target because of the absence of analogs in the host. Here, we demonstrate that antifungal peptide SP1, which is derived from the N terminus of Saccharomyces cerevisiae GAPDH (glyceraldehyde-3-phosphate dehydrogenase), disrupts the polysaccharide capsule of C. neoformans H99. The mechanism is possibly due to the interaction of SP1 with glucuronoxylomannan (GXM). Disruption of the polysaccharide capsule enhances the adhesion and phagocytosis of C. neoformans H99 by macrophages and reduces the replication of C. neoformans H99 within macrophages. Additionally, SP1 exhibits antifungal activity against cryptococcal biofilms associated with the capsular polysaccharides. These findings suggest the potential of SP1 as a drug candidate for the treatment of cryptococcosis. IMPORTANCE C. neoformans is an opportunistic pathogen that causes invasive infections with a high mortality rate. Currently, the clinical drugs available for the treatment of cryptococcosis are limited to amphotericin B, azoles, and flucytosine. Amphotericin is nephrotoxic, and the widespread use of azoles and 5-flucytosine has led to a rapid development of drug resistance in C. neoformans. There is an urgent need to develop new and effective anticryptococcal drugs. Targeting virulence factors is a novel strategy for developing antifungal drugs. The antifungal peptide SP1 is capable of disrupting the polysaccharide capsule, which is a principal virulence factor of C. neoformans. Studying the mechanism by which SP1 damages the polysaccharide capsule and investigating the potential benefits of SP1 in removing C. neoformans from the host provides baseline data to develop a therapeutic strategy against refractory cryptococcal infections. This strategy would involve both inhibiting virulence factors and directly killing C. neoformans cells.
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Affiliation(s)
- Yan Liu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
| | - Yang Zhang
- Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
- School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Xi Zhao
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
| | - Weilai Lu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
| | - Yuxin Zhong
- Department of Pancreatic and Gastric Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yu V. Fu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
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Saidykhan L, Onyishi CU, May RC. The Cryptococcus gattii species complex: Unique pathogenic yeasts with understudied virulence mechanisms. PLoS Negl Trop Dis 2022; 16:e0010916. [PMID: 36520688 PMCID: PMC9754292 DOI: 10.1371/journal.pntd.0010916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Members of Cryptococcus gattii/neoformans species complex are the etiological agents of the potentially fatal human fungal infection cryptococcosis. C. gattii and its sister species cause disease in both immunocompetent and immunocompromised hosts, while the closely related species C. neoformans and C. deneoformans predominantly infect immunocompromised hosts. To date, most studies have focused on similarities in pathogenesis between these two groups, but over recent years, important differences have become apparent. In this review paper, we highlight some of the major phenotypic differences between the C. gattii and neoformans species complexes and justify the need to study the virulence and pathogenicity of the C. gattii species complex as a distinct cryptococcal group.
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Affiliation(s)
- Lamin Saidykhan
- Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
- Division of Physical and Natural Science, University of The Gambia, Brikama Campus, West Coast Region, The Gambia
| | - Chinaemerem U. Onyishi
- Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Robin C. May
- Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
- * E-mail:
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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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Souza HI, Pereira ABM, Oliveira JR, Silva PR, Teixeira DNS, Silva-Vergara ML, Rogério AP. Cryptococcus neoformans in Association with Dermatophagoides pteronyssinus has Pro- (IL-6/STAT3 Overproduction) and Anti-inflammatory (CCL2/ERK1/2 Downregulation) Effects on Human Bronchial Epithelial Cells. Inflammation 2022; 45:1269-1280. [PMID: 35015189 DOI: 10.1007/s10753-021-01619-4] [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: 12/08/2020] [Revised: 11/23/2021] [Accepted: 12/21/2021] [Indexed: 11/29/2022]
Abstract
Cryptococcosis (caused, for example, by Cryptococcus neoformans) and allergic asthma (caused, for example, by Dermatophagoides pteronyssinus) target the respiratory tract (the lung and bronchial epithelium). C. neoformans and D. pteronyssinus can coexist in the same indoor environment, and exposure to both can cause alterations in the local airway inflammatory milieu and exacerbation of airway inflammatory diseases. Here, we evaluated the effects of the association between C. neoformans and D. pteronyssinus in the modulation of airway inflammatory responses in an in vitro experimental model using human bronchial epithelial cells. BEAS-2B cells were cultivated and stimulated with D. pteronyssinus (10 μg/mL) and/or C. neoformans (MOI 100) for 24 h. No cytotoxic effect was observed in cells stimulated by C. neoformans and/or D. pteronyssinus. The production of IL-8, IL-6, and/or CCL2, but not IL-10, as well as the activation of NF-kB, STAT3, STAT6, and/or ERK1/2 were increased in cells stimulated by C. neoformans or D. pteronyssinus compared to controls. C. neoformans in association with D. pteronyssinus inhibited the CCL2‑ERK1/2 signaling pathway in cells treated with both pathogens compared to cells stimulated by D. pteronyssinus alone. In addition, their association induced an additive effect on the IL-6/STAT3 signaling pathway in cells compared to cells stimulated with D. pteronyssinus or C. neoformans only. D. pteronyssinus increased the internalization and growth of C. neoformans in BEAS-2B cells. D. pteronyssinus in association with C. neoformans promoted pro- and anti-inflammatory responses, which can modulate cryptococcal infection and asthmaticus status.
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Affiliation(s)
- Henrique Ismarsi Souza
- Department of Clinical Medicine, Laboratory of Experimental Immunopharmacology, Institute of Health Sciences, Federal University of Triangulo Mineiro, Uberaba, Minas Gerais, Brazil
| | - Aline Beatriz Mahler Pereira
- Department of Clinical Medicine, Laboratory of Experimental Immunopharmacology, Institute of Health Sciences, Federal University of Triangulo Mineiro, Uberaba, Minas Gerais, Brazil
| | - Jhony Robison Oliveira
- Department of Clinical Medicine, Laboratory of Experimental Immunopharmacology, Institute of Health Sciences, Federal University of Triangulo Mineiro, Uberaba, Minas Gerais, Brazil
| | - Paulo Roberto Silva
- Department of Clinical Medicine, Laboratory of Experimental Immunopharmacology, Institute of Health Sciences, Federal University of Triangulo Mineiro, Uberaba, Minas Gerais, Brazil
| | - David Nascimento Silva Teixeira
- Department of Clinical Medicine, Laboratory of Experimental Immunopharmacology, Institute of Health Sciences, Federal University of Triangulo Mineiro, Uberaba, Minas Gerais, Brazil
| | - Mario Leon Silva-Vergara
- Department of Clinical Medicine, Laboratory of Mycology, Institute of Health Sciences, Federal University of Triangulo Mineiro, Uberaba, Minas Gerais, Brazil
| | - Alexandre Paula Rogério
- Department of Clinical Medicine, Laboratory of Experimental Immunopharmacology, Institute of Health Sciences, Federal University of Triangulo Mineiro, Uberaba, Minas Gerais, Brazil.
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dos Santos MH, Machado MP, Kumaresan PR, da Silva TA. Titan Cells and Yeast Forms of Cryptococcus neoformans and Cryptococcus gattii Are Recognized by GXMR-CAR. Microorganisms 2021; 9:microorganisms9091886. [PMID: 34576780 PMCID: PMC8467747 DOI: 10.3390/microorganisms9091886] [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: 08/14/2021] [Revised: 08/30/2021] [Accepted: 09/01/2021] [Indexed: 11/16/2022] Open
Abstract
Cryptococcosis, a systemic mycosis that affects both the immunocompromised and immunocompetent, is caused by the inhalation of dehydrated yeasts or fungal spores of Cryptococcus gattii or Cryptococcus neoformans. The Cryptococcus spp. polysaccharide capsule is composed mainly of glucuronoxylomannan—GXM, its major virulence factor. The capsule thickness increases to more than 15 μm during titanization, favoring the pathogenesis of cryptococcosis. Previous studies demonstrated that cytotoxic T cells that had been bioengineered with GXM-targeting chimeric antigen receptor (GXMR-CAR) were able to recognize C. neoformans by promoting the control of titanization. GXMR-CAR, a second-generation CAR, contains a single-chain variable fragment that originates from a 18B7 clone: a human IgG4 hinge, followed by a human CD28 (transmembrane/cytoplasmic domains) and a CD3ς chain. In the current study, we redirected T cells to target distinct C. neoformans and C. gattii cell types by GXMR-CAR. Lentiviral particles carrying the GXMR-CAR sequence were used to transduce Jurkat cells, and these modified cells interacted with the GXM of the C. gattii R265 strain. Moreover, GXMR-CAR mediated the recognition of C. gattii and C. neoformans yeasts with both thin and thick polysaccharide capsules, and GXMR-CAR Jurkat cells interacted with titan cells sourced from both Cryptococcus spp. Thus, bioengineered cells using CAR can improve the treatment of cryptococcosis.
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Affiliation(s)
- Matheus Henrique dos Santos
- Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 140490-900, SP, Brazil; (M.H.d.S.); (M.P.M.)
| | - Michele Procópio Machado
- Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 140490-900, SP, Brazil; (M.H.d.S.); (M.P.M.)
| | - Pappanaicken R. Kumaresan
- Department of Lymphoma and Myeloma, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA;
| | - Thiago Aparecido da Silva
- Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 140490-900, SP, Brazil; (M.H.d.S.); (M.P.M.)
- Correspondence: or ; Tel.: +55-16-3315-3049
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8
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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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Normile TG, Bryan AM, Del Poeta M. Animal Models of Cryptococcus neoformans in Identifying Immune Parameters Associated With Primary Infection and Reactivation of Latent Infection. Front Immunol 2020; 11:581750. [PMID: 33042164 PMCID: PMC7522366 DOI: 10.3389/fimmu.2020.581750] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 08/12/2020] [Indexed: 12/13/2022] Open
Abstract
Cryptococcus species are environmental fungal pathogens and the causative agents of cryptococcosis. Infection occurs upon inhalation of infectious particles, which proliferate in the lung causing a primary infection. From this primary lung infection, fungal cells can eventually disseminate to other organs, particularly the brain, causing lethal meningoencephalitis. However, in most cases, the primary infection resolves with the formation of a lung granuloma. Upon severe immunodeficiency, dormant cryptococcal cells will start proliferating in the lung granuloma and eventually will disseminate to the brain. Many investigators have sought to study the protective host immune response to this pathogen in search of host parameters that keep the proliferation of cryptococcal cells under control. The majority of the work assimilates research carried out using the primary infection animal model, mainly because a reactivation model has been available only very recently. This review will focus on anti-cryptococcal immunity in both the primary and reactivation models. An understanding of the differences in host immunity between the primary and reactivation models will help to define the key host parameters that control the infections and are important for the research and development of new therapeutic and vaccine strategies against cryptococcosis.
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Affiliation(s)
- Tyler G Normile
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY, United States
| | - Arielle M Bryan
- Ingenious Targeting Laboratory Incorporated, Ronkonkoma, NY, United States
| | - Maurizio Del Poeta
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY, United States.,Division of Infectious Diseases, School of Medicine, Stony Brook University, Stony Brook, NY, United States.,Veterans Administration Medical Center, Northport, NY, United States
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10
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Kuttel MM, Casadevall A, Oscarson S. Cryptococcus neoformans Capsular GXM Conformation and Epitope Presentation: A Molecular Modelling Study. Molecules 2020; 25:E2651. [PMID: 32517333 PMCID: PMC7321252 DOI: 10.3390/molecules25112651] [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: 05/03/2020] [Revised: 06/01/2020] [Accepted: 06/04/2020] [Indexed: 12/31/2022] Open
Abstract
The pathogenic encapsulated Cryptococcus neoformans fungus causes serious disease in immunosuppressed hosts. The capsule, a key virulence factor, consists primarily of the glucuronoxylomannan polysaccharide (GXM) that varies in composition according to serotype. While GXM is a potential vaccine target, vaccine development has been confounded by the existence of epitopes that elicit non-protective antibodies. Although there is evidence for protective antibodies binding conformational epitopes, the secondary structure of GXM remains an unsolved problem. Here an array of molecular dynamics simulations reveal that the GXM mannan backbone is consistently extended and relatively inflexible in both C. neoformans serotypes A and D. Backbone substitution does not alter the secondary structure, but rather adds structural motifs: β DGlcA and β DXyl side chains decorate the mannan backbone in two hydrophillic fringes, with mannose-6-O-acetylation forming a hydrophobic ridge between them. This work provides mechanistic rationales for clinical observations-the importance of O-acetylation for antibody binding; the lack of binding of protective antibodies to short GXM fragments; the existence of epitopes that elicit non-protective antibodies; and the self-aggregation of GXM chains-indicating that molecular modelling can play a role in the rational design of conjugate vaccines.
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Affiliation(s)
- Michelle M. Kuttel
- Department of Computer Science, University of Cape Town, Cape Town 7701, South Africa
| | - Arturo Casadevall
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, 615 N Wolfe St Room E5132, Baltimore, MD 21205, USA;
| | - Stefan Oscarson
- Centre for Synthesis and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland;
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11
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Normile TG, McEvoy K, Del Poeta M. Steryl Glycosides in Fungal Pathogenesis: An Understudied Immunomodulatory Adjuvant. J Fungi (Basel) 2020; 6:E25. [PMID: 32102324 PMCID: PMC7151148 DOI: 10.3390/jof6010025] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 02/17/2020] [Accepted: 02/20/2020] [Indexed: 12/26/2022] Open
Abstract
Invasive fungal infections pose an increasing threat to human hosts, especially in immunocompromised individuals. In response to the increasing morbidity and mortality of fungal infections, numerous groups have shown great strides in uncovering novel treatment options and potential efficacious vaccine candidates for this increasing threat due to the increase in current antifungal resistance. Steryl glycosides are lipid compounds produced by a wide range of organisms, and are largely understudied in the field of pathogenicity, especially to fungal infections. Published works over the years have shown these compounds positively modulating the host immune response. Recent advances, most notably from our lab, have strongly indicated that steryl glycosides have high efficacy in protecting the host against lethal Cryptococcal infection through acting as an immunoadjuvant. This review will summarize the keystone studies on the role of steryl glycosides in the host immune response, as well as elucidate the remaining unknown characteristics and future perspectives of these compounds for the host-fungal interactions.
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Affiliation(s)
- Tyler G. Normile
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY 11794, USA; (T.G.N.); (K.M.)
| | - Kyle McEvoy
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY 11794, USA; (T.G.N.); (K.M.)
| | - Maurizio Del Poeta
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY 11794, USA; (T.G.N.); (K.M.)
- Division of Infectious Diseases, School of Medicine, Stony Brook University, Stony Brook, NY 11794, USA
- Veterans Administration Medical Center, Northport, New York, NY 11768, USA
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12
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Zafar H, Altamirano S, Ballou ER, Nielsen K. A titanic drug resistance threat in Cryptococcus neoformans. Curr Opin Microbiol 2019; 52:158-164. [PMID: 31765991 DOI: 10.1016/j.mib.2019.11.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 10/01/2019] [Accepted: 11/01/2019] [Indexed: 10/25/2022]
Abstract
Increasing resistance to frontline antifungals is a growing threat to global health. In the face of high rates of relapse for patients with cryptococcal meningitis and frequent drug resistance in clinical isolates, recent insights into Cryptococcus neoformans morphogenesis and genome plasticity take on new and urgent meaning. Here we review the state of the understanding of mechanisms of drug resistance in the context of host-relevant changes in Cryptococcus morphology and cell ploidy.
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Affiliation(s)
- Hanna Zafar
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Sophie Altamirano
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, 55455 USA
| | - Elizabeth R Ballou
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
| | - Kirsten Nielsen
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, 55455 USA.
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de Oliveira HC, Trevijano-Contador N, Garcia-Rodas R. Cryptococcal Pathogenicity and Morphogenesis. CURRENT FUNGAL INFECTION REPORTS 2019. [DOI: 10.1007/s12281-019-00340-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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