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Mendoza SR, da Silva Ferreira M, Valente MR, Guimarães AJ. Antibody Isolation in C. neoformans. Methods Mol Biol 2024; 2775:307-328. [PMID: 38758326 DOI: 10.1007/978-1-0716-3722-7_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2024]
Abstract
The importance of humoral immunity to fungal infections remains to be elucidated. In cryptococcosis, patients that fail to generate antibodies against antigens of the fungus Cryptococcus neoformans are more susceptible to the disease, demonstrating the importance of these molecules to the antifungal immune response. Historically, antibodies against C. neoformans have been applied in diagnosis, therapeutics, and as important research tools to elucidate fungal biology. Throughout the process of generating monoclonal antibodies (mAbs) from a single B-cell clone and targeting a single epitope, several immunization steps might be required for the detection of responsive antibodies to the antigen of interest in the serum. This complex mixture of antibodies comprises the polyclonal antibodies. To obtain mAbs, B-lymphocytes are harvested (from spleen or peripheral blood) and fused with tumor myeloma cells, to generate hybridomas that are individually cloned and specifically screened for mAb production. In this chapter, we describe all the necessary steps, from the immunization to polyclonal antibody harvesting, hybridoma generation, and mAb production and purification. Additionally, we discuss new cutting-edge approaches for generating interspecies mAbs, such as humanized mAbs, or for similar species in distinct host backgrounds.
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Affiliation(s)
- Susana Ruiz Mendoza
- Laboratório de Bioquímica e Imunologia das Micoses, Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Fluminense Federal University, Niterói, RJ, Brazil
- Pós-Graduação em Imunologia e Inflamação, Instituto de Microbiologia Paulo de Góes, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Marina da Silva Ferreira
- Laboratório de Bioquímica e Imunologia das Micoses, Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Fluminense Federal University, Niterói, RJ, Brazil
- Pós-Graduação em Imunologia e Inflamação, Instituto de Microbiologia Paulo de Góes, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Michele Ramos Valente
- Laboratório de Bioquímica e Imunologia das Micoses, Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Fluminense Federal University, Niterói, RJ, Brazil
- Programa de Pós-Graduação em Microbiologia e Parasitologia Aplicadas, Instituto Biomédico, Fluminense Federal University, Niterói, RJ, Brazil
| | - Allan Jefferson Guimarães
- Laboratório de Bioquímica e Imunologia das Micoses, Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Fluminense Federal University, Niterói, RJ, Brazil.
- Pós-Graduação em Imunologia e Inflamação, Instituto de Microbiologia Paulo de Góes, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
- Programa de Pós-Graduação em Microbiologia e Parasitologia Aplicadas, Instituto Biomédico, Fluminense Federal University, Niterói, RJ, Brazil.
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Ma Y, Yang L, Jiang M, Zhao X, Xue P. Connecting Cryptococcal Meningitis and Gut Microbiome. Int J Mol Sci 2023; 24:13515. [PMID: 37686320 PMCID: PMC10487799 DOI: 10.3390/ijms241713515] [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: 08/02/2023] [Revised: 08/27/2023] [Accepted: 08/30/2023] [Indexed: 09/10/2023] Open
Abstract
Fungal pathogens of the Cryptococcus neoformans species complex (C. neoformans SC) are a major cause of fungal meningitis in immunocompromised individuals. As with other melanotic microorganisms associated with human diseases, the cell-wall-associated melanin of C. neoformans SC is a major virulence factor that contributes to its ability to evade host immune responses. The levels of melanin substrate and the regulation of melanin formation could be influenced by the microbiota-gut-brain axis. Moreover, recent studies show that C. neoformans infections cause dysbiosis in the human gut microbiome. In this review, we discuss the potential association between cryptococcal meningitis and the gut microbiome. Additionally, the significant potential of targeting the gut microbiome in the diagnosis and treatment of this debilitating disease is emphasized.
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Affiliation(s)
- Yuanyuan Ma
- Nantong Key Laboratory of Environmental Toxicology, Department of Occupational Medicine and Environmental Toxicology, School of Public Health, Nantong University, Nantong 226019, China; (Y.M.); (M.J.)
| | - Liang Yang
- School of Medicine, Southern University of Science and Technology, Shenzhen 518055, China;
| | - Mengna Jiang
- Nantong Key Laboratory of Environmental Toxicology, Department of Occupational Medicine and Environmental Toxicology, School of Public Health, Nantong University, Nantong 226019, China; (Y.M.); (M.J.)
| | - Xinyuan Zhao
- Nantong Key Laboratory of Environmental Toxicology, Department of Occupational Medicine and Environmental Toxicology, School of Public Health, Nantong University, Nantong 226019, China; (Y.M.); (M.J.)
| | - Peng Xue
- Nantong Key Laboratory of Environmental Toxicology, Department of Occupational Medicine and Environmental Toxicology, School of Public Health, Nantong University, Nantong 226019, China; (Y.M.); (M.J.)
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3
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Alves V, Martins PH, Miranda B, de Andrade IB, Pereira L, Maeda CT, de Sousa Araújo GR, Frases S. Assessing the In Vitro Potential of Glatiramer Acetate (Copaxone ®) as a Chemotherapeutic Candidate for the Treatment of Cryptococcus neoformans Infection. J Fungi (Basel) 2023; 9:783. [PMID: 37623554 PMCID: PMC10455304 DOI: 10.3390/jof9080783] [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: 06/25/2023] [Revised: 07/14/2023] [Accepted: 07/19/2023] [Indexed: 08/26/2023] Open
Abstract
Cryptococcosis is a systemic mycosis affecting immunosuppressed individuals, caused by various Cryptococcus species. The current treatment utilizes a combination of antifungal drugs, but issues such as nephrotoxicity, restricted or limited availability in certain countries, and resistance limit their effectiveness. Repurposing approved drugs presents a viable strategy for developing new antifungal options. This study investigates the potential of glatiramer acetate (Copaxone®) as a chemotherapy candidate for Cryptococcus neoformans infection. Various techniques are employed to evaluate the effects of glatiramer acetate on the fungus, including microdilution, XTT analysis, electron and light microscopy, and physicochemical measurements. The results demonstrate that glatiramer acetate exhibits antifungal properties, with an IC50 of 0.470 mg/mL and a minimum inhibitory concentration (MIC) of 2.5 mg/mL. Furthermore, it promotes enhanced cell aggregation, facilitates biofilm formation, and increases the secretion of fungal polysaccharides. These findings indicate that glatiramer acetate not only shows an antifungal effect but also modulates the key virulence factor-the polysaccharide capsule. In summary, repurposing glatiramer acetate as a potential chemotherapy option offers new prospects for combating C. neoformans infection. It addresses the limitations associated with current antifungal therapies by providing an alternative treatment approach.
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Affiliation(s)
- Vinicius Alves
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil; (V.A.); (P.H.M.); (B.M.); (I.B.d.A.); (L.P.); (G.R.d.S.A.)
| | - Pedro Henrique Martins
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil; (V.A.); (P.H.M.); (B.M.); (I.B.d.A.); (L.P.); (G.R.d.S.A.)
| | - Bruna Miranda
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil; (V.A.); (P.H.M.); (B.M.); (I.B.d.A.); (L.P.); (G.R.d.S.A.)
| | - Iara Bastos de Andrade
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil; (V.A.); (P.H.M.); (B.M.); (I.B.d.A.); (L.P.); (G.R.d.S.A.)
| | - Luiza Pereira
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil; (V.A.); (P.H.M.); (B.M.); (I.B.d.A.); (L.P.); (G.R.d.S.A.)
| | - Christina Takiya Maeda
- Laboratório de Fisiopatologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil;
| | - Glauber Ribeiro de Sousa Araújo
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil; (V.A.); (P.H.M.); (B.M.); (I.B.d.A.); (L.P.); (G.R.d.S.A.)
| | - Susana Frases
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil; (V.A.); (P.H.M.); (B.M.); (I.B.d.A.); (L.P.); (G.R.d.S.A.)
- Rede Micologia RJ, FAPERJ, Rio de Janeiro 21941-902, Brazil
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4
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Sharma KK, Singh D, Mohite SV, Williamson PR, Kennedy JF. Metal manipulators and regulators in human pathogens: A comprehensive review on microbial redox copper metalloenzymes "multicopper oxidases and superoxide dismutases". Int J Biol Macromol 2023; 233:123534. [PMID: 36740121 DOI: 10.1016/j.ijbiomac.2023.123534] [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: 11/22/2022] [Revised: 01/17/2023] [Accepted: 01/31/2023] [Indexed: 02/05/2023]
Abstract
The chemistry of metal ions with human pathogens is essential for their survival, energy generation, redox signaling, and niche dominance. To regulate and manipulate the metal ions, various enzymes and metal chelators are present in pathogenic bacteria. Metalloenzymes incorporate transition metal such as iron, zinc, cobalt, and copper in their reaction centers to perform essential metabolic functions; however, iron and copper have gained more importance. Multicopper oxidases have the ability to perform redox reaction on phenolic substrates with the help of copper ions. They have been reported from Enterobacteriaceae, namely Salmonella enterica, Escherichia coli, and Yersinia enterocolitica, but their role in virulence is still poorly understood. Similarly, superoxide dismutases participate in reducing oxidative stress and allow the survival of pathogens. Their role in virulence and survival is well established in Salmonella typhimurium and Mycobacterium tuberculosis. Further, to ensure survival against stress, like metal starvation or metal toxicity, redox metalloenzymes and metal transportation systems of pathogens actively participate in metal homeostasis. Recently, the omics and protein structure biology studies have helped to predict new targets for regulation the colonization potential of the pathogenic strains. The current review is focused on the major roles of redox metalloenzymes, especially MCOs and SODs of human pathogenic bacteria.
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Affiliation(s)
- Krishna Kant Sharma
- Laboratory of Enzymology and Gut Microbiology, Department of Microbiology, Maharshi Dayanand University, Rohtak 124001, Haryana, India.
| | - Deepti Singh
- Laboratory of Enzymology and Gut Microbiology, Department of Microbiology, Maharshi Dayanand University, Rohtak 124001, Haryana, India
| | - Shreya Vishwas Mohite
- Laboratory of Enzymology and Gut Microbiology, Department of Microbiology, Maharshi Dayanand University, Rohtak 124001, Haryana, India
| | - Peter R Williamson
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - John F Kennedy
- Chembiotech Laboratories, Advanced Science and Technology Institute, 5 the Croft, Buntsford Drive, Stoke Heath, Bromsgrove, Worcs B60 4JE, UK
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Qadri H, Shah AH, Alkhanani M, Almilaibary A, Mir MA. Immunotherapies against human bacterial and fungal infectious diseases: A review. Front Med (Lausanne) 2023; 10:1135541. [PMID: 37122338 PMCID: PMC10140573 DOI: 10.3389/fmed.2023.1135541] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Accepted: 03/15/2023] [Indexed: 05/02/2023] Open
Abstract
Nations' ongoing struggles with a number of novel and reemerging infectious diseases, including the ongoing global health issue, the SARS-Co-V2 (severe acute respiratory syndrome coronavirus 2) outbreak, serve as proof that infectious diseases constitute a serious threat to the global public health. Moreover, the fatality rate in humans is rising as a result of the development of severe infectious diseases brought about by multiple drug-tolerant pathogenic microorganisms. The widespread use of traditional antimicrobial drugs, immunosuppressive medications, and other related factors led to the establishment of such drug resistant pathogenic microbial species. To overcome the difficulties commonly encountered by current infectious disease management and control processes, like inadequate effectiveness, toxicities, and the evolution of drug tolerance, new treatment solutions are required. Fortunately, immunotherapies already hold great potential for reducing these restrictions while simultaneously expanding the boundaries of healthcare and medicine, as shown by the latest discoveries and the success of drugs including monoclonal antibodies (MAbs), vaccinations, etc. Immunotherapies comprise methods for treating diseases that specifically target or affect the body's immune system and such immunological procedures/therapies strengthen the host's defenses to fight those infections. The immunotherapy-based treatments control the host's innate and adaptive immune responses, which are effective in treating different pathogenic microbial infections. As a result, diverse immunotherapeutic strategies are being researched more and more as alternative treatments for infectious diseases, leading to substantial improvements in our comprehension of the associations between pathogens and host immune system. In this review we will explore different immunotherapies and their usage for the assistance of a broad spectrum of infectious ailments caused by various human bacterial and fungal pathogenic microbes. We will discuss about the recent developments in the therapeutics against the growing human pathogenic microbial diseases and focus on the present and future of using immunotherapies to overcome these diseases. Graphical AbstractThe graphical abstract shows the therapeutic potential of different types of immunotherapies like vaccines, monoclonal antibodies-based therapies, etc., against different kinds of human Bacterial and Fungal microbial infections.
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Affiliation(s)
- Hafsa Qadri
- Department of Bioresources, School of Biological Sciences, University of Kashmir, Srinagar, Jammu and Kashmir, India
| | - Abdul Haseeb Shah
- Department of Bioresources, School of Biological Sciences, University of Kashmir, Srinagar, Jammu and Kashmir, India
- *Correspondence: Abdul Haseeb Shah,
| | - Mustfa Alkhanani
- Department of Biology, College of Sciences, University of Hafr Al Batin, Hafar Al Batin, Saudi Arabia
| | - Abdullah Almilaibary
- Department of Family and Community Medicine, Faculty of Medicine, Al Baha University, Al Baha, Saudi Arabia
| | - Manzoor Ahmad Mir
- Department of Bioresources, School of Biological Sciences, University of Kashmir, Srinagar, Jammu and Kashmir, India
- Manzoor Ahmad Mir,
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6
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Erives VH, Munzen ME, Zamith-Miranda D, Hernandez H, Manepalli S, Nguyen LN, Hamed MF, Nosanchuk JD, Martinez LR. Methamphetamine Enhances Cryptococcus neoformans Melanization, Antifungal Resistance, and Pathogenesis in a Murine Model of Drug Administration and Systemic Infection. Infect Immun 2022; 90:e0009122. [PMID: 35357221 PMCID: PMC9022586 DOI: 10.1128/iai.00091-22] [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: 02/28/2022] [Accepted: 03/02/2022] [Indexed: 11/20/2022] Open
Abstract
Methamphetamine (METH) is a major public health and safety problem in the United States. Chronic METH abuse is associated with a 2-fold-higher risk of HIV infection and, possibly, additional infections, particularly those that enter through the respiratory tract or skin. Cryptococcus neoformans is an encapsulated opportunistic yeast-like fungus that is a relatively frequent cause of meningoencephalitis in immunocompromised patients, especially in individuals with AIDS. C. neoformans melanizes during mammalian infection in a process that presumably uses host-supplied compounds such as catecholamines. l-3,4-Dihydroxyphenylalanine (l-Dopa) is a natural catecholamine that is frequently used to induce melanization in C. neoformans. l-Dopa-melanized cryptococci manifest resistance to radiation, phagocytosis, detergents, and heavy metals. Using a systemic mouse model of infection and in vitro assays to critically assess the impact of METH on C. neoformans melanization and pathogenesis, we demonstrated that METH-treated mice infected with melanized yeast cells showed increased fungal burdens in the blood and brain, exacerbating mortality. Interestingly, analyses of cultures of METH-exposed cryptococci supplemented with l-Dopa revealed that METH accelerates fungal melanization, an event of adaptation to external stimuli that can be advantageous to the fungus during pathogenesis. Our findings provide novel evidence of the impact of METH abuse on host homeostasis and increased permissiveness to opportunistic microorganisms.
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Affiliation(s)
- Victor H. Erives
- Department of Biological Sciences, The Border Biomedical Research Center, The University of Texas at El Paso, El Paso, Texas, USA
| | - Melissa E. Munzen
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - Daniel Zamith-Miranda
- Department of Medicine (Division of Infectious Diseases), Albert Einstein College of Medicine, Bronx, New York, USA
| | - Hazael Hernandez
- Department of Biological Sciences, The Border Biomedical Research Center, The University of Texas at El Paso, El Paso, Texas, USA
- Texas Tech University Health Sciences Center, Lubbock, Texas, USA
| | - Swetha Manepalli
- Department of Biomedical Sciences, Long Island University-Post, Brookville, New York, USA
| | - Long N. Nguyen
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Mohamed F. Hamed
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
- Department of Pathology, Faculty of Veterinary Medicine, Mansoura University, Mansoura, Egypt
| | - Joshua D. Nosanchuk
- Department of Medicine (Division of Infectious Diseases), Albert Einstein College of Medicine, Bronx, New York, USA
| | - Luis R. Martinez
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
- Department of Biomedical Sciences, Long Island University-Post, Brookville, New York, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, USA
- Center for Immunology and Transplantation, University of Florida, Gainesville, Florida, USA
- Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, Florida, USA
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Baker RP, Chrissian C, Stark RE, Casadevall A. Cryptococcus neoformans melanization incorporates multiple catecholamines to produce polytypic melanin. J Biol Chem 2022; 298:101519. [PMID: 34942148 PMCID: PMC8760516 DOI: 10.1016/j.jbc.2021.101519] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 12/14/2021] [Accepted: 12/16/2021] [Indexed: 01/08/2023] Open
Abstract
Melanin is a major virulence factor in pathogenic fungi that enhances the ability of fungal cells to resist immune clearance. Cryptococcus neoformans is an important human pathogenic fungus that synthesizes melanin from exogenous tissue catecholamine precursors during infection, but the type of melanin made in cryptococcal meningoencephalitis is unknown. We analyzed the efficacy of various catecholamines found in brain tissue in supporting melanization using animal brain tissue and synthetic catecholamine mixtures reflecting brain tissue proportions. Solid-state NMR spectra of the melanin pigment produced from such mixtures yielded more melanin than expected if only the preferred constituent dopamine had been incorporated, suggesting uptake of additional catecholamines. Probing the biosynthesis of melanin using radiolabeled catecholamines revealed that C. neoformans melanization simultaneously incorporated more than one catecholamine, implying that the pigment was polytypic in nature. Nonetheless, melanin derived from individual or mixed catecholamines had comparable ability to protect C. neoformans against ultraviolet light and oxidants. Our results indicate that melanin produced during infection differs depending on the catecholamine composition of tissue and that melanin pigment synthesized in vivo is likely to accrue from the polymerization of a mixture of precursors. From a practical standpoint, our results strongly suggest that using dopamine as a polymerization precursor is capable of producing melanin pigment comparable to that produced during infection. On a more fundamental level, our findings uncover additional structural complexity for natural cryptococcal melanin by demonstrating that pigment produced during human infection is likely to be composed of polymerized moieties derived from chemically different precursors.
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Affiliation(s)
- Rosanna P Baker
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA
| | - Christine Chrissian
- Department of Chemistry and Biochemistry, The City College of New York and CUNY Institute for Macromolecular Assemblies, New York, New York, USA
| | - Ruth E Stark
- Department of Chemistry and Biochemistry, The City College of New York and CUNY Institute for Macromolecular Assemblies, New York, New York, USA; Ph.D. Program in Biochemistry, The Graduate Center of the City University of New York, New York, New York, USA; Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, New York, New York, USA
| | - Arturo Casadevall
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA.
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A Specific Mixture of Propolis and Carnosic Acid Triggers a Strong Fungicidal Action against Cryptococcus neoformans. Antibiotics (Basel) 2021; 10:antibiotics10111395. [PMID: 34827333 PMCID: PMC8614879 DOI: 10.3390/antibiotics10111395] [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: 10/19/2021] [Revised: 11/03/2021] [Accepted: 11/09/2021] [Indexed: 11/17/2022] Open
Abstract
Current antifungal chemotherapy against the prevalent basidiomycete Cryptococcus neoformans displays some drawbacks. This pathogenic fungus is refractory to echinocandins, whereas conventional treatment with amphotericin B plus 5-fluorocytosine has a limited efficacy. In this study, we explored the potential cryptococcal activity of some natural agents. After conducting a screening test with a set of propolis from different geographical areas, we selected an extract from China, which displayed a certain cytotoxic activity against C. neoformans, due to this extract being cheap and easily available in large amounts. The combination of this kind of propolis with carnosic acid in a 1:4 ratio induced a stronger fungicidal effect, which occurred following a synergistic pattern, without visible alterations in external cell morphology. Furthermore, several carnosic acid–propolis formulations applied onto preformed biofilms decreased the metabolic activity of the sessile cells forming biofilms. These data support the potential application of mixtures containing these two natural extracts in the design of new antifungal strategies in order to combat opportunistic infections caused by prevalent pathogenic fungi.
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Kreusch MG, Duarte RTD. Photoprotective compounds and radioresistance in pigmented and non-pigmented yeasts. Appl Microbiol Biotechnol 2021; 105:3521-3532. [PMID: 33900423 DOI: 10.1007/s00253-021-11271-5] [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: 11/06/2020] [Revised: 03/28/2021] [Accepted: 04/05/2021] [Indexed: 10/21/2022]
Abstract
Ultraviolet radiation, continuously reaching our planet's surface, is a type of electromagnetic energy within the wavelength range of 10 to 400 nm. Despite essential for all life on Earth, ultraviolet radiation may have severe adverse cellular effects, including DNA dimerization and production of reactive oxygen species. Radioresistant microorganisms can survive under high doses of ultraviolet radiation, enduring the direct and indirect effects on nucleic acids and other biomolecules. The synthesis and accumulation of photoprotective compounds are among the main strategies employed by radioresistant yeast species to bear the harmful effects of ultraviolet radiation. A correlation between pigments and resistance to ultraviolet radiation has been widely recognized in these microorganisms; however, there is still some debate on this topic, with non-pigmented strains sometimes being more resistant than their pigmented counterparts. In this review, we explore the role of photoprotective compounds-specifically, melanin, carotenoids, and mycosporines-and compare the differences found in resistance between pigmented and non-pigmented yeasts. We also discuss the biotechnological potential of these photoprotective compounds, with special emphasis on those produced by non-pigmented yeast strains, such as phytoene and phytofluene. The use of "-omics" approaches should further unveil the radioresistance mechanisms of non-pigmented yeasts, opening new opportunities for both research and commercial applications. KEY POINTS: • Updated knowledge on photoprotective compounds from radioresistant yeasts. • Differences on radioresistance between pigmented and non-pigmented yeasts. • Future prospects over the study of non-pigmented photoprotective compounds.
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Affiliation(s)
- Marianne Gabi Kreusch
- Laboratory of Molecular Ecology and Extremophiles, Department of Microbiology, Immunology and Parasitology, Federal University of Santa Catarina, Florianópolis, SC, Brazil
| | - Rubens Tadeu Delgado Duarte
- Laboratory of Molecular Ecology and Extremophiles, Department of Microbiology, Immunology and Parasitology, Federal University of Santa Catarina, Florianópolis, SC, Brazil.
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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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11
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Bhattacharya S, Bouklas T, Fries BC. Replicative Aging in Pathogenic Fungi. J Fungi (Basel) 2020; 7:6. [PMID: 33375605 PMCID: PMC7824483 DOI: 10.3390/jof7010006] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 12/16/2020] [Accepted: 12/23/2020] [Indexed: 12/14/2022] Open
Abstract
Candida albicans, Candida auris, Candida glabrata, and Cryptococcus neoformans are pathogenic yeasts which can cause systemic infections in immune-compromised as well as immune-competent individuals. These yeasts undergo replicative aging analogous to a process first described in the nonpathogenic yeast Saccharomyces cerevisiae. The hallmark of replicative aging is the asymmetric cell division of mother yeast cells that leads to the production of a phenotypically distinct daughter cell. Several techniques to study aging that have been pioneered in S. cerevisiae have been adapted to study aging in other pathogenic yeasts. The studies indicate that aging is relevant for virulence in pathogenic fungi. As the mother yeast cell progressively ages, every ensuing asymmetric cell division leads to striking phenotypic changes, which results in increased antifungal and antiphagocytic resistance. This review summarizes the various techniques that are used to study replicative aging in pathogenic fungi along with their limitations. Additionally, the review summarizes some key phenotypic variations that have been identified and are associated with changes in virulence or resistance and thus promote persistence of older cells.
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Affiliation(s)
- Somanon Bhattacharya
- Department of Medicine, Stony Brook University, Stony Brook, NY 11794, USA; (T.B.); (B.C.F.)
| | - Tejas Bouklas
- Department of Medicine, Stony Brook University, Stony Brook, NY 11794, USA; (T.B.); (B.C.F.)
- Department of Biological Sciences, State University of New York College at Old Westbury, Old Westbury, NY 11568, USA
| | - Bettina C. Fries
- Department of Medicine, Stony Brook University, Stony Brook, NY 11794, USA; (T.B.); (B.C.F.)
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY 11794, USA
- Veterans Administration Medical Center, Northport, NY 11768, USA
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12
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Wongsuk T, Homkaew A, Faksri K, Thongnak C. Multi-locus Sequence Typing and Whole Genome Sequence Analysis of Cryptococcus neoformans Isolated from Clinical Specimens in Vajira Hospital, Bangkok, Thailand. Mycopathologia 2020; 185:503-514. [PMID: 32440853 DOI: 10.1007/s11046-020-00456-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 05/12/2020] [Indexed: 12/17/2022]
Abstract
The basidiomycete yeast Cryptococcus neoformans causes disease in immunocompromized patients. Whole genome sequencing (WGS) technology provides insights into the molecular epidemiology of C. neoformans. However, the number of such studies is limited. Here we used WGS and multilocus sequence typing (MLST) to determine the genetic diversity of C. neoformans isolates and genetic structures of their populations among patients admitted to a single hospital in Bangkok, Thailand. Seven isolates from six patients collected during 1 year were identified as C. neoformans sensu stricto according to colony morphology, microscopy, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and nucleotide sequence analysis of internal transcribed sequences. These isolates were sensitive to the antifungal drugs amphotericin B, fluconazole, 5-flucytosine, voriconazole, itraconazole and posaconazole and were mating type α and molecular type VNI. MLST analysis identified ST4, ST5 and ST6. We further employed WGS to determine the genetic diversity and relationships of C. neoformans isolated here combined with C. neoformans sequences data acquired from a public database (n = 42). We used the data to construct a phylogenetic tree. WGS provided additional genomics data and achieved high discriminatory power for identifying C. neoformans isolates isolated in Thailand. This report further demonstrates the applicability of WGS analysis for conducting molecular epidemiology and provides insight into the genetic diversity of C. neoformans isolates from one hospital in Thailand.
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Affiliation(s)
- Thanwa Wongsuk
- Department of Clinical Pathology, Faculty of Medicine Vajira Hospital, Navamindradhiraj University, 681 Samsen Road, Vajira District, Dusit, Bangkok, 10300, Thailand
| | - Anchalee Homkaew
- Microbiology Laboratory, Department of Central Laboratory and Blood Bank, Faculty of Medicine Vajira Hospital, Navamindradhiraj University, Bangkok, Thailand
| | - Kiatichai Faksri
- Research and Diagnostic Center for Emerging Infectious Diseases, and Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Chuphong Thongnak
- Department of Clinical Pathology, Faculty of Medicine Vajira Hospital, Navamindradhiraj University, 681 Samsen Road, Vajira District, Dusit, Bangkok, 10300, Thailand.
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13
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Boniche C, Rossi SA, Kischkel B, Vieira Barbalho F, Nogueira D’Aurea Moura Á, Nosanchuk JD, Travassos LR, Pelleschi Taborda C. Immunotherapy against Systemic Fungal Infections Based on Monoclonal Antibodies. J Fungi (Basel) 2020; 6:jof6010031. [PMID: 32121415 PMCID: PMC7151209 DOI: 10.3390/jof6010031] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 02/22/2020] [Accepted: 02/25/2020] [Indexed: 12/17/2022] Open
Abstract
The increasing incidence in systemic fungal infections in humans has increased focus for the development of fungal vaccines and use of monoclonal antibodies. Invasive mycoses are generally difficult to treat, as most occur in vulnerable individuals, with compromised innate and adaptive immune responses. Mortality rates in the setting of our current antifungal drugs remain excessively high. Moreover, systemic mycoses require prolonged durations of antifungal treatment and side effects frequently occur, particularly drug-induced liver and/or kidney injury. The use of monoclonal antibodies with or without concomitant administration of antifungal drugs emerges as a potentially efficient treatment modality to improve outcomes and reduce chemotherapy toxicities. In this review, we focus on the use of monoclonal antibodies with experimental evidence on the reduction of fungal burden and prolongation of survival in in vivo disease models. Presently, there are no licensed monoclonal antibodies for use in the treatment of systemic mycoses, although the potential of such a vaccine is very high as indicated by the substantial promising results from several experimental models.
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Affiliation(s)
- Camila Boniche
- Biomedical Sciences Institute, Department of Microbiology, University of São Paulo, Sao Paulo 05508-000, Brazil; (C.B.); (S.A.R.); (B.K.); (F.V.B.)
| | - Suélen Andreia Rossi
- Biomedical Sciences Institute, Department of Microbiology, University of São Paulo, Sao Paulo 05508-000, Brazil; (C.B.); (S.A.R.); (B.K.); (F.V.B.)
| | - Brenda Kischkel
- Biomedical Sciences Institute, Department of Microbiology, University of São Paulo, Sao Paulo 05508-000, Brazil; (C.B.); (S.A.R.); (B.K.); (F.V.B.)
| | - Filipe Vieira Barbalho
- Biomedical Sciences Institute, Department of Microbiology, University of São Paulo, Sao Paulo 05508-000, Brazil; (C.B.); (S.A.R.); (B.K.); (F.V.B.)
| | - Ágata Nogueira D’Aurea Moura
- Tropical Medicine Institute, Department of Dermatology, Faculty of Medicine, University of Sao Paulo, Sao Paulo 05403-000, Brazil;
| | - Joshua D. Nosanchuk
- Departments of Medicine (Division of Infectious Diseases) and Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY 10461, USA;
| | - Luiz R. Travassos
- Department of Microbiology, Immunology and Parasitology, Federal University of São Paulo, Sao Paulo 04021-001, Brazil;
| | - Carlos Pelleschi Taborda
- Biomedical Sciences Institute, Department of Microbiology, University of São Paulo, Sao Paulo 05508-000, Brazil; (C.B.); (S.A.R.); (B.K.); (F.V.B.)
- Tropical Medicine Institute, Department of Dermatology, Faculty of Medicine, University of Sao Paulo, Sao Paulo 05403-000, Brazil;
- Correspondence:
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14
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Kimura TFE, Romera LMD, de Almeida SR. Fonsecaea pedrosoi Conidia Induces Activation of Dendritic Cells and Increases CD11c + Cells in Regional Lymph Nodes During Experimental Chromoblastomycosis. Mycopathologia 2020; 185:245-256. [PMID: 32008205 DOI: 10.1007/s11046-020-00429-w] [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: 09/17/2018] [Accepted: 01/21/2020] [Indexed: 10/20/2022]
Abstract
The chromoblastomycosis is a subcutaneous mycosis with a high morbidity rate, Fonsecaea pedrosoi being the largest etiologic agent of this mycosis, usually confined to the skin and subcutaneous tissues. Rarely people get the cure, because the therapies shown to be deficient and few studies report the host-parasite relationship. Dendritic cells (DCs) are specialized in presenting antigens to naïve T lymphocytes inducing primary immune responses. Therefore, we propose to study the migratory capacity of DCs after infection with conidia of F. pedrosoi. The phenotype of DCs was evaluated using cells obtained from footpad and lymph nodes of BALB/c mice after 12, 24 and 72 h of infection. After 24 and 72 h of infection, we found a significant decrease in DCs in footpad and a significant increase in the lymph nodes after 72 h. The expression of surface markers and co-stimulatory molecules were reduced in cells obtained from footpad. To better assess the migratory capacity of DCs migration from footpad, CFSE-stained conidia were injected subcutaneously. We found that after 12 and 72 h, CD11c+ cells were increased in regional lymph nodes, leading us to believe that DCs (CD11c+) were able to phagocytic conidia present in footpad and migrated to regional lymph nodes.
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Affiliation(s)
- Telma Fátima Emidio Kimura
- Laboratory of Mycology, Department of Clinical and Toxicological Analyses, Faculty of Pharmaceutical Scienses, Universidade de Sao Paulo, São Paulo, Brazil
| | - Lavínia Maria Dal'Mas Romera
- Laboratory of Mycology, Department of Clinical and Toxicological Analyses, Faculty of Pharmaceutical Scienses, Universidade de Sao Paulo, São Paulo, Brazil.
| | - Sandro Rogério de Almeida
- Laboratory of Mycology, Department of Clinical and Toxicological Analyses, Faculty of Pharmaceutical Scienses, Universidade de Sao Paulo, São Paulo, Brazil
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15
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Abstract
Melanins are dark green, brown, or black pigments that serve as antioxidant, reactive oxygen species (ROS) scavengers that protect fungal pathogens from radiation and host immune responses. Cryptococcus neoformans, the major etiological agent of fungal meningoencephalitis, also utilizes melanin as a key virulence factor. In this basidiomycete pathogen, melanin production is regulated by the cAMP and high-osmolarity glycerol response (HOG) pathways, and yet its complex signaling networks remain poorly described. In this study, we uncovered novel melanin synthesis regulatory networks consisting of core transcription factors (TFs), including Bzp4, Usv101, Hob1, and Mbs1, and core kinases Gsk3 and Kic1. These networks were identified through coupling systematic analyses of the expression and epistatic relationships of TF and kinase mutant libraries in the presence of diverse melanin substrates with transcriptome profiling of the core TF mutants. Thus, this report provides comprehensive insight into the melanin-regulating pathways in C. neoformans and other fungal pathogens. Melanin is an antioxidant polyphenol pigment required for the pathogenicity of many fungal pathogens, but comprehensive regulatory mechanisms remain unidentified. In this study, we systematically analyzed melanin-regulating signaling pathways in Cryptococcus neoformans and identified four melanin-regulating core transcription factors (TFs), Bzp4, Usv101, Mbs1, and Hob1, required for induction of the laccase gene (LAC1). Bzp4, Usv101, and Mbs1 independently regulate LAC1 induction, whereas Hob1 controls Bzp4 and Usv101 expression. Both Bzp4 and Usv101 are localized in the cytoplasm under nutrient-rich conditions (i.e., in the presence of yeast extract-peptone-dextrose [YPD] medium) but translocate into the nucleus upon nutrient starvation (i.e., in the presence of yeast nitrogen base [YNB] medium without glucose), and Mbs1 is constitutively localized in the nucleus. Notably, the cAMP pathway is not involved in regulation of the four TFs, but the high-osmolarity glycerol response (HOG) pathway negatively regulates induction of BZP4 and LAC1. Next, we searched for potential kinases upstream of the core TFs and identified nine core kinases; their deletion led to defective melanin production and LAC1 induction. Deletion of GSK3 or KIC1 abolished induction of LAC1 and BZP4 and perturbed nuclear translocation of Bzp4. Notably, Gsk3 also regulated expression of HOB1, USV101, and MBS1, indicating that it is a critical melanin-regulating kinase. Finally, an RNA sequencing-based transcriptome analysis of the wild-type strain and of bzp4Δ, usv101Δ, hob1Δ, and mbs1Δ strains under nutrient-rich and nutrient-starved conditions revealed that the melanin-regulating core TFs govern redundant and distinct classes of genes involved in a variety of biological processes.
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16
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Hernandez H, Erives VH, Martinez LR. Coccidioidomycosis: Epidemiology, Fungal Pathogenesis, and Therapeutic Development. CURRENT TROPICAL MEDICINE REPORTS 2019; 6:132-144. [PMID: 34367879 DOI: 10.1007/s40475-019-00184-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Purpose of Review Coccidioidomycosis can result from the inhalation of infectious spores of Coccidioides species (spp.) immitis or posadasii. Clinical manifestations range from mild flu-like disease to severe disseminated infection that can require life-long therapy. Burden of this mycosis is high in the southwest region of the USA where it is well characterized, and in many areas of Mexico and Latin America where it is inadequately characterized. Here, we provide historical data and current knowledge on Coccidioides spp. pathogenesis as well as recent progress in therapeutic and vaccine development against coccidioidomycosis. Recent Findings The virulence mechanisms of Coccidioides spp. are largely unknown; however, production and regulation of a spherule glycoprotein, ammonium production, and melanization have all been proposed as integral factors in Coccidioides spp.' pathogenesis. Therapeutic options are limited and not 100% effective, but individualized treatment with triazoles or amphotericin B over the course of pulmonary or disseminated infection can be effective in resolution of coccidioidomycosis. Human immunization has not been achieved but efforts are ongoing. Summary Advances in therapeutic and vaccine development are imperative for the prevention and treatment of coccidioidomycosis, especially for those individuals at risk either living or traveling to or from endemic areas.
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Affiliation(s)
- Hazael Hernandez
- Department of Biological Sciences, The Border Biomedical Research Center, The University of Texas at El Paso, 500 W. University Ave., Bioscience Research Building, Room 2.170, El Paso, TX 79968-9991, USA
| | - Victor H Erives
- Department of Biological Sciences, The Border Biomedical Research Center, The University of Texas at El Paso, 500 W. University Ave., Bioscience Research Building, Room 2.170, El Paso, TX 79968-9991, USA
| | - Luis R Martinez
- Department of Biological Sciences, The Border Biomedical Research Center, The University of Texas at El Paso, 500 W. University Ave., Bioscience Research Building, Room 2.170, El Paso, TX 79968-9991, USA
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17
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Chatterjee S, Prados-Rosales R, Tan S, Phan VC, Chrissian C, Itin B, Wang H, Khajo A, Magliozzo RS, Casadevall A, Stark RE. The melanization road more traveled by: Precursor substrate effects on melanin synthesis in cell-free and fungal cell systems. J Biol Chem 2018; 293:20157-20168. [PMID: 30385508 PMCID: PMC6311522 DOI: 10.1074/jbc.ra118.005791] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Revised: 10/29/2018] [Indexed: 01/25/2023] Open
Abstract
Natural brown-black eumelanin pigments confer structural coloration in animals and potently block ionizing radiation and antifungal drugs. These functions also make them attractive for bioinspired materials design, including coating materials for drug-delivery vehicles, strengthening agents for adhesive hydrogel materials, and free-radical scavengers for soil remediation. Nonetheless, the molecular determinants of the melanin "developmental road traveled" and the resulting architectural features have remained uncertain because of the insoluble, heterogeneous, and amorphous characteristics of these complex polymeric assemblies. Here, we used 2D solid-state NMR, EPR, and dynamic nuclear polarization spectroscopic techniques, assisted in some instances by the use of isotopically enriched precursors, to address several open questions regarding the molecular structures and associated functions of eumelanin. Our findings uncovered: 1) that the identity of the available catecholamine precursor alters the structure of melanin pigments produced either in Cryptococcus neoformans fungal cells or under cell-free conditions; 2) that the identity of the available precursor alters the scaffold organization and membrane lipid content of melanized fungal cells; 3) that the fungal cells are melanized preferentially by an l-DOPA precursor; and 4) that the macromolecular carbon- and nitrogen-based architecture of cell-free and fungal eumelanins includes indole, pyrrole, indolequinone, and open-chain building blocks that develop depending on reaction time. In conclusion, the availability of catecholamine precursors plays an important role in eumelanin development by affecting the efficacy of pigment formation, the melanin molecular structure, and its underlying scaffold in fungal systems.
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Affiliation(s)
- Subhasish Chatterjee
- From the Department of Chemistry and Biochemistry, The City College of New York and CUNY Institute for Macromolecular Assemblies, New York, New York 10031,.
| | - Rafael Prados-Rosales
- the Department of Microbiology and Immunology, Albert Einstein College of Medicine, Yeshiva University, Bronx, New York 10461,; CIC bioGUNE, Derio, Vizcaya 48160, Spain
| | - Sindy Tan
- From the Department of Chemistry and Biochemistry, The City College of New York and CUNY Institute for Macromolecular Assemblies, New York, New York 10031
| | - Van Chanh Phan
- the Department of Natural Sciences, CUNY Hostos Community College, Bronx, New York 10451
| | - Christine Chrissian
- From the Department of Chemistry and Biochemistry, The City College of New York and CUNY Institute for Macromolecular Assemblies, New York, New York 10031,; the City University of New York, Ph.D. Program in Biochemistry, New York, New York 10036
| | - Boris Itin
- the New York Structural Biology Center, New York, New York 10027
| | - Hsin Wang
- From the Department of Chemistry and Biochemistry, The City College of New York and CUNY Institute for Macromolecular Assemblies, New York, New York 10031
| | - Abdelahad Khajo
- the Department of Chemistry, CUNY Brooklyn College, Brooklyn, New York 11210,; the City University of New York, Ph.D. Program in Chemistry, New York, New York 10036, and
| | - Richard S Magliozzo
- the City University of New York, Ph.D. Program in Biochemistry, New York, New York 10036,; the Department of Chemistry, CUNY Brooklyn College, Brooklyn, New York 11210,; the City University of New York, Ph.D. Program in Chemistry, New York, New York 10036, and
| | - Arturo Casadevall
- the Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205
| | - Ruth E Stark
- From the Department of Chemistry and Biochemistry, The City College of New York and CUNY Institute for Macromolecular Assemblies, New York, New York 10031,; the City University of New York, Ph.D. Program in Biochemistry, New York, New York 10036,; the City University of New York, Ph.D. Program in Chemistry, New York, New York 10036, and
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18
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PAS Domain Protein Pas3 Interacts with the Chromatin Modifier Bre1 in Regulating Cryptococcal Morphogenesis. mBio 2018; 9:mBio.02135-18. [PMID: 30425151 PMCID: PMC6234864 DOI: 10.1128/mbio.02135-18] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
For the ubiquitous environmental pathogen Cryptococcus neoformans, the morphological transition from yeast to filament confers resistance to natural predators like soil amoeba and is an integral differentiation event to produce infectious spores. Interestingly, filamentation is immuno-stimulatory and attenuates cryptococcal virulence in a mammalian host. Consistently, the morphogenesis transcription factor Znf2 profoundly shapes cryptococcal interaction with various hosts. Identifying the signaling pathways activating filamentation is thus, conductive to a better understanding of cryptococcal biology. In this study, we identified a PAS domain protein Pas3 that functions upstream of Znf2 in regulating cryptococcal filamentation. Interestingly, Pas3 interacts with the chromatin modifier Bre1 in the nucleus to regulate the transcript level of Znf2 and its prominent downstream targets. This is the first example of a PAS domain signaling regulator interacting with a chromatin modifier to control filamentation through their impact on cryptococcal transcriptome. Switching between different morphotypes is an adaptive cellular response in many microbes. In Cryptococcus neoformans, the yeast-to-hypha transition confers resistance to microbial predation in the soil and is an integral part of its life cycle. Morphogenesis is also known to be associated with virulence, with the filamentous form being immune-stimulatory and protective in mammalian models of cryptococcosis. Previous studies identified the transcription factor Znf2 as a master regulator of cryptococcal filamentation. However, the upstream regulators of Znf2 remain largely unknown. PAS domain proteins have long been recognized as transducers of diverse environmental signals. Here, we identified a PAS domain protein Pas3 as an upstream regulator of Znf2. Surprisingly, this small Pas3 protein lacks a nuclear localization signal but is enriched in the nucleus where it regulates the transcript level of ZNF2 and its prominent downstream targets. We discovered that the PAS domain is essential for Pas3’s nuclear enrichment and function. Intriguingly, Pas3 interacts with Bre1, which is required for Cryptococcus histone H2B monoubiquitination (H2Bub1) and H3 lysine 4 dimethylation (H3K4me2), two histone modifications known to be associated with active gene transcription. Indeed, Bre1 functions together with Pas3 in regulating cryptococcal filamentation based on loss-of-function, epistasis, and transcriptome analysis. These findings provide the first evidence of a signaling regulator acting with a chromatin modifier to control cryptococcal filamentation.
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19
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Vij R, Cordero RJB, Casadevall A. The Buoyancy of Cryptococcus neoformans Is Affected by Capsule Size. mSphere 2018; 3:e00534-18. [PMID: 30404928 PMCID: PMC6222054 DOI: 10.1128/msphere.00534-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 10/17/2018] [Indexed: 12/16/2022] Open
Abstract
Cryptococcus neoformans is an environmental pathogenic fungus with a worldwide geographical distribution that is responsible for hundreds of thousands of human cryptococcosis cases each year. During infection, the yeast undergoes a morphological transformation involving capsular enlargement that increases microbial volume. To understand the factors that play a role in environmental dispersal of C. neoformans and C. gattii, we evaluated the cell density of Cryptococcus using Percoll isopycnic gradients. We found differences in the cell densities of strains belonging to C. neoformans and C. gattii species complexes. The buoyancy of C. neoformans strains varied depending on growth medium. In minimal medium, the cryptococcal capsule made a major contribution to the cell density such that cells with larger capsules had lower density than those with smaller capsules. Removing the capsule, by chemical or mechanical methods, increased the C. neoformans cell density and reduced buoyancy. Melanization of the C. neoformans cell wall, which also contributes to virulence, produced a small but consistent increase in cell density. Encapsulated C. neoformans sedimented much more slowly in seawater as its density approached the density of water. Our results suggest a new function for the capsule whereby it can function as a flotation device to facilitate transport and dispersion in aqueous fluids.IMPORTANCE The buoyancy of a microbial cell is an important physical characteristic that may affect its transportability in fluids and interactions with tissues during infection. The polysaccharide capsule surrounding C. neoformans is required for infection and dissemination in the host. Our results indicate that the capsule has a significant effect on reducing cryptococcal cell density, altering its sedimentation in seawater. Modulation of microbial cell density via encapsulation may facilitate dispersal for other important encapsulated pathogens.
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Affiliation(s)
- Raghav Vij
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Radames J B Cordero
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Arturo Casadevall
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
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20
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Pinto L, Granja LFZ, Almeida MAD, Alviano DS, Silva MHD, Ejzemberg R, Rozental S, Alviano CS. Melanin particles isolated from the fungus Fonsecaea pedrosoi activates the human complement system. Mem Inst Oswaldo Cruz 2018; 113:e180120. [PMID: 29947713 PMCID: PMC6014723 DOI: 10.1590/0074-02760180120] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Accepted: 05/23/2018] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Melanin production has been associated with virulence in various pathogenic fungi, including Fonsecaea pedrosoi, the major etiological agent for chromoblastomycosis, a subcutaneous fungal disease that occurs in South America. OBJECTIVE The aim of this study was to evaluate the effects of acid-basic extracted F. pedrosoi melanin particles and fungal cell ghosts obtained by Novozym 234 treatment on their ability to activate the human complement system. METHODS The ability of melanin particles and fungal cell ghosts to activate the human complement system was evaluated by complement consumption, immunofluorescence, and enzyme-linked immunosorbent assay (ELISA). FINDINGS Unsensitised melanin particles and melanin ghosts presented complement consumption of 82.67 ± 2.08% and 96.04 ± 1.13%, respectively. Immunofluorescence assays revealed intense deposition of the C3 and C4 fragments on the surface of melanin particles and ghosts extracted from F. pedrosoi. Deposition of the C3, C4, and C5 fragments onto melanin samples and zymosan was confirmed by ELISA. Deposition of small amounts of C1q and C9 onto melanin samples and zymosan was detected by ELISA. CONCLUSION Fonsecaea pedrosoi melanin particles and fungal cell ghosts activated the complement system mainly through an alternative pathway.
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Affiliation(s)
- Lysianne Pinto
- Universidade Federal do Rio de Janeiro, Instituto de Microbiologia Professor Paulo de Góes, Rio de Janeiro, RJ, Brasil
| | - Luiz Fernando Zmetek Granja
- Universidade Federal do Rio de Janeiro, Instituto de Microbiologia Professor Paulo de Góes, Rio de Janeiro, RJ, Brasil
| | - Mariana Amorim de Almeida
- Universidade Federal do Rio de Janeiro, Instituto de Macromoléculas Professora Eloisa Mano, Rio de Janeiro, RJ, Brasil
| | - Daniela Sales Alviano
- Universidade Federal do Rio de Janeiro, Instituto de Microbiologia Professor Paulo de Góes, Rio de Janeiro, RJ, Brasil
| | - Maria Helena da Silva
- Universidade Federal do Rio de Janeiro, Instituto de Microbiologia Professor Paulo de Góes, Rio de Janeiro, RJ, Brasil
| | - Regina Ejzemberg
- Universidade Federal do Rio de Janeiro, Instituto de Microbiologia Professor Paulo de Góes, Rio de Janeiro, RJ, Brasil
| | - Sonia Rozental
- Universidade Federal do Rio de Janeiro, Instituto de Biofísica Carlos Chagas Filho, Rio de Janeiro, RJ, Brasil
| | - Celuta Sales Alviano
- Universidade Federal do Rio de Janeiro, Instituto de Microbiologia Professor Paulo de Góes, Rio de Janeiro, RJ, Brasil
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21
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Esher SK, Zaragoza O, Alspaugh JA. Cryptococcal pathogenic mechanisms: a dangerous trip from the environment to the brain. Mem Inst Oswaldo Cruz 2018; 113:e180057. [PMID: 29668825 PMCID: PMC5909089 DOI: 10.1590/0074-02760180057] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 03/08/2018] [Indexed: 12/16/2022] Open
Abstract
Cryptococcus neoformans is an opportunistic pathogenic yeast that causes serious infections, most commonly of the central nervous system (CNS). C. neoformans is mainly found in the environment and acquired by inhalation. It could be metaphorically imagined that cryptococcal disease is a "journey" for the microorganism that starts in the environment, where this yeast loads its suitcase with virulence traits. C. neoformans first encounters the infected mammalian host in the lungs, a site in which it must choose the right elements from its "virulence suitcase" to survive the pulmonary immune response. However, the lung is often only the first stop in this journey, and in some individuals the fungal trip continues to the brain. To enter the brain, C. neoformans must "open" the main barrier that protects this organ, the blood brain barrier (BBB). Once in the brain, C. neoformans expresses a distinct set of protective attributes that confers a strong neurotropism and the ability to cause brain colonisation. In summary, C. neoformans is a unique fungal pathogen as shown in its ability to survive in the face of multiple stress factors and to express virulence factors that contribute to the development of disease.
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Affiliation(s)
- Shannon K Esher
- Duke University School of Medicine, Department of Molecular Genetics and Microbiology, Department of Medicine, Durham, USA
| | - Oscar Zaragoza
- Instituto de Salud Carlos III, National Centre for Microbiology, Mycology Reference Laboratory, Madrid, Spain
| | - James Andrew Alspaugh
- Duke University School of Medicine, Department of Molecular Genetics and Microbiology, Department of Medicine, Durham, USA
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22
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Mukaremera L, Lee KK, Wagener J, Wiesner DL, Gow NA, Nielsen K. Titan cell production in Cryptococcus neoformans reshapes the cell wall and capsule composition during infection. Cell Surf 2018; 1:15-24. [PMID: 30123851 PMCID: PMC6095662 DOI: 10.1016/j.tcsw.2017.12.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2017] [Revised: 12/05/2017] [Accepted: 12/31/2017] [Indexed: 12/21/2022] Open
Abstract
Cryptococcus neoformans is a human fungal pathogen that often causes infections in immunocompromised individuals. Upon inhalation into the lungs C. neoformans differentiates into cells with altered size and morphology, including production of large titan cells. Titan cells possess thickened cell wall and dense, cross-linked capsule when compared to in vitro grown cells. In addition, titan cells have increased cell wall chitin that is associated with a detrimental anti-inflammatory immune response. Here we examined the cell wall and capsule composition of in vitro, in vivo typical-sized and in vivo titan cells using High Performance Liquid Chromatography (HPLC). The monomer composition of cell wall polysaccharides showed that in vivo C. neoformans cells contained more glucosamine and less glucose than in vitro cells, suggesting alteration in abundance of both chitin and glucans, respectively. Low levels of galactosamine were also detected in carbohydrates from both in vivo and vitro cells. Within the in vivo cell population, differences in the proportions of cell wall and capsule monomers between typical and titan cells were also observed. Taken together, these results demonstrate that C. neoformans reshapes its cell wall and capsule composition during infection. These cell wall and capsule alterations likely help C. neoformans escape recognition by, and allow modulation of, the host immune system.
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Affiliation(s)
- Liliane Mukaremera
- Department of Microbiology and Immunology, Medical School, University of Minnesota, Minneapolis, USA
| | - Keunsook K. Lee
- MRC Centre for Medical Mycology, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - Jeanette Wagener
- MRC Centre for Medical Mycology, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - Darin L. Wiesner
- Department of Microbiology and Immunology, Medical School, University of Minnesota, Minneapolis, USA
| | - Neil A.R. Gow
- MRC Centre for Medical Mycology, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - Kirsten Nielsen
- Department of Microbiology and Immunology, Medical School, University of Minnesota, Minneapolis, USA
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23
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Barcellos VA, Martins LMS, Fontes ACL, Reuwsaat JCV, Squizani ED, de Sousa Araújo GR, Frases S, Staats CC, Schrank A, Kmetzsch L, Vainstein MH. Genotypic and Phenotypic Diversity of Cryptococcus gattii VGII Clinical Isolates and Its Impact on Virulence. Front Microbiol 2018; 9:132. [PMID: 29467743 PMCID: PMC5808156 DOI: 10.3389/fmicb.2018.00132] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 01/19/2018] [Indexed: 12/11/2022] Open
Abstract
The Cryptococcus gattii species complex harbors the main etiological agents of cryptococcosis in immunocompetent patients. C. gattii molecular type VGII predominates in the north and northeastern regions of Brazil, leading to high morbidity and mortality rates. C. gattii VGII isolates have a strong clinical relevance and phenotypic variations. These phenotypic variations among C. gattii species complex isolates suggest that some strains are more virulent than others, but little information is available related to the pathogenic properties of those strains. In this study, we analyzed some virulence determinants of C. gattii VGII strains (CG01, CG02, and CG03) isolated from patients in the state of Piauí, Brazil. The C. gattii R265 VGIIa strain, which was isolated from the Vancouver outbreak, differed from C. gattii CG01, CG02 and CG03 isolates (also classified as VGII) when analyzed the capsular dimensions, melanin production, urease activity, as well as the glucuronoxylomannan (GXM) secretion. Those differences directly reflected in their virulence potential. In addition, CG02 displayed higher virulence compared to R265 (VGIIa) strain in a cryptococcal murine model of infection. Lastly, we examined the genotypic diversity of these strains through Multilocus Sequence Type (MLST) and one new subtype was described for the CG02 isolate. This study confirms the presence and the phenotypic and genotypic diversity of highly virulent strains in the Northeast region of Brazil.
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Affiliation(s)
- Vanessa A Barcellos
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Liline M S Martins
- Laboratório de Imunogenética e Biologia Molecular, Universidade Federal do Piauí, Teresina, Brazil.,Faculdade de Ciências Médicas da Universidade Estadual do Piauí, Teresina, Brazil
| | - Alide C L Fontes
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Julia C V Reuwsaat
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Eamim D Squizani
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Glauber R de Sousa Araújo
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Susana Frases
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Charley C Staats
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Departamento de Biologia Molecular e Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Augusto Schrank
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Departamento de Biologia Molecular e Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Livia Kmetzsch
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Departamento de Biologia Molecular e Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Marilene H Vainstein
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Departamento de Biologia Molecular e Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
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24
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Antimicrobial Octapeptin C4 Analogues Active against Cryptococcus Species. Antimicrob Agents Chemother 2018; 62:AAC.00986-17. [PMID: 29158283 PMCID: PMC5786788 DOI: 10.1128/aac.00986-17] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 11/08/2017] [Indexed: 12/31/2022] Open
Abstract
Resistance to antimicrobials is a growing problem in both developed and developing countries. In nations where AIDS is most prevalent, the human fungal pathogen Cryptococcus neoformans is a significant contributor to mortality, and its growing resistance to current antifungals is an ever-expanding threat. We investigated octapeptin C4, from the cationic cyclic lipopeptide class of antimicrobials, as a potential new antifungal. Octapeptin C4 was a potent, selective inhibitor of this fungal pathogen with an MIC of 1.56 μg/ml. Further testing of octapeptin C4 against 40 clinical isolates of C. neoformans var. grubii or neoformans showed an MIC of 1.56 to 3.13 μg/ml, while 20 clinical isolates of C. neoformans var. gattii had an MIC of 0.78 to 12.5 μg/ml. In each case, the MIC values for octapeptin C4 were equivalent to, or better than, current antifungal drugs fluconazole and amphotericin B. The negatively charged polysaccharide capsule of C. neoformans influences the pathogen's sensitivity to octapeptin C4, whereas the degree of melanization had little effect. Testing synthetic octapeptin C4 derivatives provided insight into the structure activity relationships, revealing that the lipophilic amino acid moieties are more important to the activity than the cationic diaminobutyric acid groups. Octapeptins have promising potential for development as anticryptococcal therapeutic agents.
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25
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Nutritional Requirements and Their Importance for Virulence of Pathogenic Cryptococcus Species. Microorganisms 2017; 5:microorganisms5040065. [PMID: 28974017 PMCID: PMC5748574 DOI: 10.3390/microorganisms5040065] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 09/27/2017] [Accepted: 09/27/2017] [Indexed: 12/12/2022] Open
Abstract
Cryptococcus sp. are basidiomycete yeasts which can be found widely, free-living in the environment. Interactions with natural predators, such as amoebae in the soil, are thought to have promoted the development of adaptations enabling the organism to survive inside human macrophages. Infection with Cryptococcus in humans occurs following inhalation of desiccated yeast cells or spore particles and may result in fatal meningoencephalitis. Human disease is caused almost exclusively by the Cryptococcus neoformans species complex, which predominantly infects immunocompromised patients, and the Cryptococcus gattii species complex, which is capable of infecting immunocompetent individuals. The nutritional requirements of Cryptococcus are critical for its virulence in animals. Cryptococcus has evolved a broad range of nutrient acquisition strategies, many if not most of which also appear to contribute to its virulence, enabling infection of animal hosts. In this review, we summarise the current understanding of nutritional requirements and acquisition in Cryptococcus and offer perspectives to its evolution as a significant pathogen of humans.
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26
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Yang CL, Wang J, Zou LL. Innate immune evasion strategies against Cryptococcal meningitis caused by Cryptococcus neoformans. Exp Ther Med 2017; 14:5243-5250. [PMID: 29285049 PMCID: PMC5740712 DOI: 10.3892/etm.2017.5220] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 05/31/2017] [Indexed: 12/14/2022] Open
Abstract
As an infectious fungus that affects the respiratory tract, Cryptococcus neoformans (C. neoformans) commonly causes asymptomatic pulmonary infection. C. neoformans may target the brain instead of the lungs and cross the blood-brain barrier (BBB) in the early phase of infection; however, this is dependent on successful evasion of the host innate immune system. During the initial stage of fungal infection, a complex network of innate immune factors are activated. C. neoformans utilizes a number of strategies to overcome the anti-fungal mechanisms of the host innate immune system and cross the BBB. In the present review, the defensive mechanisms of C. neoformans against the innate immune system and its ability to cross the BBB were discussed, with an emphasis on recent insights into the activities of anti-phagocytotic and anti-oxidative factors in C. neoformans.
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Affiliation(s)
- Cheng-Liang Yang
- Translational Neuroscience and Neural Regeneration and Repair Institute, The First Hospital of Yichang, China Three Gorges University, Yichang, Hubei 443002, P.R. China.,Institute of Cell Therapy, The First Hospital of Yichang, China Three Gorges University, Yichang, Hubei 443002, P.R. China
| | - Jun Wang
- Translational Neuroscience and Neural Regeneration and Repair Institute, The First Hospital of Yichang, China Three Gorges University, Yichang, Hubei 443002, P.R. China.,Institute of Cell Therapy, The First Hospital of Yichang, China Three Gorges University, Yichang, Hubei 443002, P.R. China
| | - Li-Li Zou
- Translational Neuroscience and Neural Regeneration and Repair Institute, The First Hospital of Yichang, China Three Gorges University, Yichang, Hubei 443002, P.R. China.,Institute of Cell Therapy, The First Hospital of Yichang, China Three Gorges University, Yichang, Hubei 443002, P.R. China.,Department of Microbiology and Immunology, Medical College, China Three Gorges University, Yichang, Hubei 443002, P.R. China
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27
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Physiological Differences in Cryptococcus neoformans Strains In Vitro versus In Vivo and Their Effects on Antifungal Susceptibility. Antimicrob Agents Chemother 2017; 61:AAC.02108-16. [PMID: 28031206 PMCID: PMC5328578 DOI: 10.1128/aac.02108-16] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Cryptococcus neoformans is an environmentally ubiquitous fungal pathogen that primarily causes disease in people with compromised immune systems, particularly those with advanced AIDS. There are estimated to be almost 1 million cases per year of cryptococcal meningitis in patients infected with human immunodeficiency virus, leading to over 600,000 annual deaths, with a particular burden in sub-Saharan Africa. Amphotericin B (AMB) and fluconazole (FLC) are key components of cryptococcal meningitis treatment: AMB is used for induction, and FLC is for consolidation, maintenance and, for occasional individuals, prophylaxis. However, the results of standard antifungal susceptibility testing (AFST) for AMB and FLC do not correlate well with therapeutic outcomes and, consequently, no clinical breakpoints have been established. While a number of explanations for this absence of correlation have been proffered, one potential reason that has not been adequately explored is the possibility that the physiological differences between the in vivo infection environment and the in vitro AFST environment lead to disparate drug susceptibilities. These susceptibility-influencing factors include melanization, which does not occur during AFST, the size of the polysaccharide capsule, which is larger in infecting cells than in those grown under normal laboratory conditions, and the presence of large polyploid "titan cells," which rarely occur under laboratory conditions. Understanding whether and how C. neoformans differentially expresses mechanisms of resistance to AMB and FLC in the AFST environment compared to the in vivo environment could enhance our ability to interpret AFST results and possibly lead to the development of more applicable testing methods.
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28
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Surawut S, Ondee T, Taratummarat S, Palaga T, Pisitkun P, Chindamporn A, Leelahavanichkul A. The role of macrophages in the susceptibility of Fc gamma receptor IIb deficient mice to Cryptococcus neoformans. Sci Rep 2017; 7:40006. [PMID: 28074867 PMCID: PMC5225418 DOI: 10.1038/srep40006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 11/30/2016] [Indexed: 02/04/2023] Open
Abstract
Dysfunctional polymorphisms of FcγRIIb, an inhibitory receptor, are associated with Systemic Lupus Erythaematosus (SLE). Cryptococcosis is an invasive fungal infection in SLE, perhaps due to the de novo immune defect. We investigated cryptococcosis in the FcγRIIb-/- mouse-lupus-model. Mortality, after intravenous C. neoformans-induced cryptococcosis, in young (8-week-old) and older (24-week-old) FcγRIIb-/- mice, was higher than in age-matched wild-types. Severe cryptococcosis in the FcγRIIb-/- mice was demonstrated by high fungal burdens in the internal organs with histological cryptococcoma-like lesions and high levels of TNF-α and IL-6, but not IL-10. Interestingly, FcγRIIb-/- macrophages demonstrated more prominent phagocytosis but did not differ in killing activity in vitro and the striking TNF-α, IL-6 and IL-10 levels, compared to wild-type cells. Indeed, in vivo macrophage depletion with liposomal clodronate attenuated the fungal burdens in FcγRIIb-/- mice, but not wild-type mice. When administered to wild-type mice, FcγRIIb-/- macrophages with phagocytosed Cryptococcus resulted in higher fungal burdens than FcγRIIb+/+ macrophages with phagocytosed Cryptococcus. These results support, at least in part, a model whereby, in FcγRIIb-/- mice, enhanced C. neoformans transmigration occurs through infected macrophages. In summary, prominent phagocytosis, with limited effective killing activity, and high pro-inflammatory cytokine production by FcγRIIb-/- macrophages were correlated with more severe cryptococcosis in FcγRIIb-/- mice.
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Affiliation(s)
- Saowapha Surawut
- Medical Microbiology, Interdisciplinary Program, Graduate School, Chulalongkorn University, Bangkok, Thailand
| | - Thunnicha Ondee
- Medical Sciences Program, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Sujittra Taratummarat
- Medical Microbiology, Interdisciplinary Program, Graduate School, Chulalongkorn University, Bangkok, Thailand
| | - Tanapat Palaga
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
- Department of Microbiology, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - Prapaporn Pisitkun
- Division of Allergy, Immunology, and Rheumatology, Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Ariya Chindamporn
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Asada Leelahavanichkul
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
- Center of Excellence in Immunology and Immune-mediated Diseases, Department of Microbiology, Faculty of Medicine, Bangkok, Thailand
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29
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Activation of Melanin Synthesis in Alternaria infectoria by Antifungal Drugs. Antimicrob Agents Chemother 2015; 60:1646-55. [PMID: 26711773 DOI: 10.1128/aac.02190-15] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 12/15/2015] [Indexed: 12/28/2022] Open
Abstract
The importance of Alternaria species fungi to human health ranges from their role as etiological agents of serious infections with poor prognoses in immunosuppressed individuals to their association with respiratory allergic diseases. The present work focuses on Alternaria infectoria, which was used as a model organism of the genus, and was designed to unravel melanin production in response to antifungals. After we characterized the pigment produced by A. infectoria, we studied the dynamics of 1,8-dihydroxynaphthalene (DHN)-melanin production during growth, the degree of melanization in response to antifungals, and how melanization affected susceptibility to several classes of therapeutic drugs. We demonstrate that A. infectoria increased melanin deposition in cell walls in response to nikkomycin Z, caspofungin, and itraconazole but not in response to fluconazole or amphotericin B. These results indicate that A. infectoria activates DHN-melanin synthesis in response to certain antifungal drugs, possibly as a protective mechanism against these drugs. Inhibition of DHN-melanin synthesis by pyroquilon resulted in a lower minimum effective concentration (MEC) of caspofungin and enhanced morphological changes (increased hyphal balloon size), characterized by thinner and less organized A. infectoria cell walls. In summary, A. infectoria synthesizes melanin in response to certain antifungal drugs, and its susceptibility is influenced by melanization, suggesting the therapeutic potential of drug combinations that affect melanin synthesis.
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30
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COLOMBO ANACAROLINE, RODRIGUES MARCIOL. Fungal colonization of the brain: anatomopathological aspects of neurological cryptococcosis. ACTA ACUST UNITED AC 2015; 87:1293-309. [DOI: 10.1590/0001-3765201520140704] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Brain infection by the fungus Cryptococcus neoformans results in an estimated 500,000 human deaths per annum. Colonization of the central nervous system (CNS) by C. neoformans causes different clinical syndromes that involve interaction of a number of fungal components with distinct brain cells. In this manuscript, our literature review confirmed the notion that the Cryptococcus field is expanding rapidly, but also suggested that studies on neuropathogenesis still represent a small fraction of basic research activity in the field. We therefore discussed anatomical and physiological aspects of the brain during infection by C. neoformans, in addition to mechanisms by which brain resident cells interact with the fungus. This review suggests that multiple efforts are necessary to improve the knowledge on how C. neoformans affects brain cells, in order to enable the generation of new therapeutic tools in a near future.
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Affiliation(s)
- ANA CAROLINE COLOMBO
- Universidade Federal do Rio de Janeiro, Brazil; Universidade Federal do Rio de Janeiro, Brazil
| | - MARCIO L. RODRIGUES
- Universidade Federal do Rio de Janeiro, Brazil; Fundação Oswaldo Cruz, Brazil
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31
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Rodrigues J, Fonseca FL, Schneider RO, Godinho RMDC, Firacative C, Maszewska K, Meyer W, Schrank A, Staats C, Kmetzsch L, Vainstein MH, Rodrigues ML. Pathogenic diversity amongst serotype C VGIII and VGIV Cryptococcus gattii isolates. Sci Rep 2015; 5:11717. [PMID: 26153364 PMCID: PMC4495446 DOI: 10.1038/srep11717] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 05/27/2015] [Indexed: 12/11/2022] Open
Abstract
Cryptococcus gattii is one of the causative agents of human cryptococcosis. Highly virulent strains of serotype B C. gattii have been studied in detail, but little information is available on the pathogenic properties of serotype C isolates. In this study, we analyzed pathogenic determinants in three serotype C C. gattii isolates (106.97, ATCC 24066 and WM 779). Isolate ATCC 24066 (molecular type VGIII) differed from isolates WM 779 and 106.97 (both VGIV) in capsule dimensions, expression of CAP genes, chitooligomer distribution, and induction of host chitinase activity. Isolate WM 779 was more efficient than the others in producing pigments and all three isolates had distinct patterns of reactivity with antibodies to glucuronoxylomannan. This great phenotypic diversity reflected in differential pathogenicity. VGIV isolates WM 779 and 106.97 were similar in their ability to cause lethality and produced higher pulmonary fungal burden in a murine model of cryptococcosis, while isolate ATCC 24066 (VGIII) was unable to reach the brain and caused reduced lethality in intranasally infected mice. These results demonstrate a high diversity in the pathogenic potential of isolates of C. gattii belonging to the molecular types VGIII and VGIV.
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Affiliation(s)
- Jéssica Rodrigues
- Instituto de Microbiologia Paulo de Góes, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Fernanda L Fonseca
- Fundação Oswaldo Cruz - Fiocruz, Centro de Desenvolvimento Tecnológico em Saúde (CDTS), Rio de Janeiro, Brazil
| | - Rafael O Schneider
- Centro de Biotecnologia, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Rodrigo M da C Godinho
- Instituto de Microbiologia Paulo de Góes, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Carolina Firacative
- 1] Molecular Mycology Research Laboratory, Centre for Infectious Diseases and Microbiology, Sydney Medical School - Westmead Hospital, Marie Bashir Institute for Infectious Diseases and Biosecurity, The University of Sydney, Westmead Millennium Institute, Sydney, Australia [2] Grupo de Microbiología, Instituto Nacional de Salud, Bogotá, Colombia
| | - Krystyna Maszewska
- Molecular Mycology Research Laboratory, Centre for Infectious Diseases and Microbiology, Sydney Medical School - Westmead Hospital, Marie Bashir Institute for Infectious Diseases and Biosecurity, The University of Sydney, Westmead Millennium Institute, Sydney, Australia
| | - Wieland Meyer
- Molecular Mycology Research Laboratory, Centre for Infectious Diseases and Microbiology, Sydney Medical School - Westmead Hospital, Marie Bashir Institute for Infectious Diseases and Biosecurity, The University of Sydney, Westmead Millennium Institute, Sydney, Australia
| | - Augusto Schrank
- Centro de Biotecnologia, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Charley Staats
- Centro de Biotecnologia, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Livia Kmetzsch
- Centro de Biotecnologia, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Marilene H Vainstein
- Centro de Biotecnologia, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Marcio L Rodrigues
- 1] Instituto de Microbiologia Paulo de Góes, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil [2] Fundação Oswaldo Cruz - Fiocruz, Centro de Desenvolvimento Tecnológico em Saúde (CDTS), Rio de Janeiro, Brazil
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Abstract
Fungal infections are responsible for millions of human deaths annually. Copper, an essential but toxic trace element, plays an important role at the host-pathogen axis during infection. In this review, we describe how the host uses either Cu compartmentalization within innate immune cells or Cu sequestration in other infected host niches such as in the brain to combat fungal infections. We explore Cu toxicity mechanisms and the Cu homeostasis machinery that fungal pathogens bring into play to succeed in establishing an infection. Finally, we address recent approaches that manipulate Cu-dependent processes at the host-pathogen axis for antifungal drug development.
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Affiliation(s)
| | - Dennis J Thiele
- From the Departments of Pharmacology & Cancer Biology and Biochemistry, Duke University, School of Medicine, Durham, North Carolina 27710
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Quantitative trait locus mapping of melanization in the plant pathogenic fungus Zymoseptoria tritici. G3-GENES GENOMES GENETICS 2014; 4:2519-33. [PMID: 25360032 PMCID: PMC4267946 DOI: 10.1534/g3.114.015289] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Melanin plays an important role in virulence and antimicrobial resistance in several fungal pathogens. The wheat pathogen Zymoseptoria tritici is important worldwide, but little is known about the genetic architecture of pathogenicity, including the production of melanin. Because melanin production can exhibit complex inheritance, we used quantitative trait locus (QTL) mapping in two crosses to identify the underlying genes. Restriction site−associated DNA sequencing was used to genotype 263 (cross 1) and 261 (cross 2) progeny at ~8500 single-nucleotide polymorphisms and construct two dense linkage maps. We measured gray values, representing degrees of melanization, for single-spore colonies growing on Petri dishes by using a novel image-processing approach that enabled high-throughput phenotyping. Because melanin production can be affected by stress, each offspring was grown in two stressful environments and one control environment. We detected six significant QTL in cross 1 and nine in cross 2, with three QTL shared between the crosses. Different QTL were identified in different environments and at different colony ages. By obtaining complete genome sequences for the four parents and analyzing sequence variation in the QTL confidence intervals, we identified 16 candidate genes likely to affect melanization. One of these candidates was PKS1, a polyketide synthase gene known to play a role in the synthesis of dihydroxynaphthalene melanin. Three candidate quantitative trait nucleotides were identified in PKS1. Many of the other candidate genes were not previously associated with melanization.
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34
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Sabiiti W, Robertson E, Beale MA, Johnston SA, Brouwer AE, Loyse A, Jarvis JN, Gilbert AS, Fisher MC, Harrison TS, May RC, Bicanic T. Efficient phagocytosis and laccase activity affect the outcome of HIV-associated cryptococcosis. J Clin Invest 2014; 124:2000-8. [PMID: 24743149 DOI: 10.1172/jci72950] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 02/06/2014] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Cryptococcal meningitis (CM) is a leading cause of HIV-associated mortality globally. High fungal burden in cerebrospinal fluid (CSF) at diagnosis and poor fungal clearance during treatment are recognized adverse prognostic markers; however, the underlying pathogenic factors that drive these clinical manifestations are incompletely understood. We profiled a large set of clinical isolates for established cryptococcal virulence traits to evaluate the contribution of C. neoformans phenotypic diversity to clinical presentation and outcome in human cryptococcosis. METHODS Sixty-five C. neoformans isolates from clinical trial patients with matched clinical data were assayed in vitro to determine murine macrophage uptake, intracellular proliferation rate (IPR), capsule induction, and laccase activity. Analysis of the correlation between prognostic clinical and host immune parameters and fungal phenotypes was performed using Spearman's r, while the fungal-dependent impact on long-term survival was determined by Cox regression analysis. RESULTS High levels of fungal uptake by macrophages in vitro, but not the IPR, were associated with CSF fungal burden (r = 0.38, P = 0.002) and long-term patient survival (hazard ratio [HR] 2.6, 95% CI 1.2-5.5, P = 0.012). High-uptake strains were hypocapsular (r = -0.28, P = 0.05) and exhibited enhanced laccase activity (r = 0.36, P = 0.003). Fungal isolates with greater laccase activity exhibited heightened survival ex vivo in purified CSF (r = 0.49, P < 0.0001) and resistance to clearance following patient antifungal treatment (r = 0.39, P = 0.003). CONCLUSION These findings underscore the contribution of cryptococcal-phagocyte interactions and laccase-dependent melanin pathways to human clinical presentation and outcome. Furthermore, characterization of fungal-specific pathways that drive clinical manifestation provide potential targets for the development of therapeutics and the management of CM. FUNDING This work was made possible by funding from the Wellcome Trust (WT088148MF), the Medical Research Council (MR/J008176/1), the NIHR Surgical Reconstruction and Microbiology Research Centre and the Lister Institute for Preventive Medicine (to R.C. May), and a Wellcome Trust Intermediate fellowship (089966, to T. Bicanic). The C. neoformans isolates were collected within clinical trials funded by the British Infection Society (fellowship to T. Bicanic), the Wellcome Trust (research training fellowships WT069991, to A.E. Brouwer and WT081794, to J.N. Jarvis), and the Medical Research Council, United Kingdom (76201). The funding sources had no role in the design or conduct of this study, nor in preparation of the manuscript.
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Liu D, Wei L, Guo T, Tan W. Detection of DOPA-melanin in the dimorphic fungal pathogen Penicillium marneffei and its effect on macrophage phagocytosis in vitro. PLoS One 2014; 9:e92610. [PMID: 24647795 PMCID: PMC3960263 DOI: 10.1371/journal.pone.0092610] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 02/24/2014] [Indexed: 02/05/2023] Open
Abstract
The fungal pathogen Penicillium marneffei produces melanin-like pigment in vitro. The synthetic pathway of melanin and its possible influence in the protective yeast cells surviving within macrophage cells are not known. In this work, P. marneffei produced brown black pigment in the presence of L-DOPA and black particles were extracted from yeast cells treated with proteolytic enzymes, denaturant and concentrated hot acid. Kojic acid inhibited the brown-black pigment production of P. marneffei yeast grown on brain heart infusion agar. Transmitting electron microscopy showed spherical granular electron-dense particles with an average diameter of 100 nm in a beaded arrangement in the innermost cell wall. Electron-paramagnetic resonance revealed that the black particles contain a stable free radical compound. The UV-visible and Fourier transform infrared spectra of particles extracted from P. marneffei and synthetic DOPA-melanin showed a high degree of similarity. Melanized yeast cells decreased phagocytosis by macrophage cells and increased resistance to intracellular digestion in vitro. These results indicate that P. marneffei can synthesize DOPA-melanin or melanin-like compounds in vitro and suggest that the DOPA-melanin pathway is associated with cell wall structure and enhances the resistance to phagocytosis by macrophages.
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Affiliation(s)
- Donghua Liu
- Department of Dermatology and Venereology, First Affiliated Hospital, Guangxi Medical University, Nanning, China
- * E-mail:
| | - Lili Wei
- Department of Dermatology and Venereology, First Affiliated Hospital, Guangxi Medical University, Nanning, China
| | - Ting Guo
- Department of Dermatology and Venereology, First Affiliated Hospital, Guangxi Medical University, Nanning, China
| | - Weifen Tan
- Department of Dermatology and Venereology, First Affiliated Hospital, Guangxi Medical University, Nanning, China
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Cheon SA, Jung KW, Bahn YS, Kang HA. The unfolded protein response (UPR) pathway in Cryptococcus. Virulence 2013; 5:341-50. [PMID: 24504058 DOI: 10.4161/viru.26774] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Unique and evolutionarily conserved signaling pathways allow an organism to sense, respond to, and adapt to internal and external environmental cues at its biological niche. In eukaryotic cells, the unfolded protein response (UPR) pathway regulates endoplasmic reticulum (ER) homeostasis upon exposure to environmental changes causing ER stress. The UPR pathway of Cryptococcus neoformans, an opportunistic fungal pathogen, which causes life-threatening meningoencephalitis in immunocompromised individuals, consists of the evolutionarily conserved Ire1 kinase, a unique bZIP transcription factor, Hxl1, and the ER-resident molecular chaperone Kar2/BiP. Although the Cryptococcus UPR pathway regulates ER stress, antifungal drug resistance, and virulence in an Ire1/Hxl1-dependent manner, Ire1 has Hxl1-independent roles in capsule biosynthesis and thermotolerance. In this review, we highlight the conserved and unique features of the Cryptococcus UPR pathway compared with other fungal UPR systems and its importance in the pathogenesis of cryptococcosis and discuss future challenges in this field.
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Affiliation(s)
- Seon Ah Cheon
- Department of Life Science; Research Center for Biomolecules and Biosystems; College of Natural Science; Chung-Ang University; Seoul, Korea; Department of Agricultural Biotechnology and Center for Fungal Pathogenesis; Seoul National University; Seoul, Korea
| | - Kwang-Woo Jung
- Department of Biotechnology; Center for Fungal Pathogenesis; Yonsei University; Seoul, Korea
| | - Yong-Sun Bahn
- Department of Biotechnology; Center for Fungal Pathogenesis; Yonsei University; Seoul, Korea
| | - Hyun Ah Kang
- Department of Life Science; Research Center for Biomolecules and Biosystems; College of Natural Science; Chung-Ang University; Seoul, Korea
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The polyketide synthase gene pks4 of Trichoderma reesei provides pigmentation and stress resistance. EUKARYOTIC CELL 2013; 12:1499-508. [PMID: 24036343 DOI: 10.1128/ec.00103-13] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Species of the fungal genus Trichoderma (Hypocreales, Ascomycota) are well-known for their production of various secondary metabolites. Nonribosomal peptides and polyketides represent a major portion of these products. In a recent phylogenomic investigation of Trichoderma polyketide synthase (PKS)-encoding genes, the pks4 from T. reesei was shown to be an orthologue of pigment-forming PKSs involved in synthesis of aurofusarin and bikaverin in Fusarium spp. In this study, we show that deletion of this gene in T. reesei results in loss of green conidial pigmentation and in pigmentation alteration of teleomorph structures. It also has an impact on conidial cell wall stability and the antagonistic abilities of T. reesei against other fungi, including formation of inhibitory metabolites. In addition, deletion of pks4 significantly influences the expression of other PKS-encoding genes of T. reesei. To our knowledge, this is the first indication that a low-molecular-weight pigment-forming PKS is involved in defense, mechanical stability, and stress resistance in fungi.
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Lee IR, Morrow CA, Fraser JA. Nitrogen regulation of virulence in clinically prevalent fungal pathogens. FEMS Microbiol Lett 2013; 345:77-84. [PMID: 23701678 DOI: 10.1111/1574-6968.12181] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 05/17/2013] [Accepted: 05/18/2013] [Indexed: 11/25/2022] Open
Abstract
The habitats of fungal pathogens range from environmental to commensal, and the nutrient content of these different niches varies considerably. Upon infection of humans, nutrient availability changes significantly depending on the site and pathophysiology of infection. Nonetheless, a common feature enabling successful establishment in these niches is the ability to metabolise available nutrients including sources of nitrogen, carbon and essential metals such as iron. In particular, nitrogen source utilisation influences specific morphological transitions, sexual and asexual sporulation and virulence factor production. All these physiological changes confer selective advantages to facilitate fungal survival, proliferation and colonisation. The three most well-studied components of the nitrogen regulatory circuit that commonly impact fungal pathogenesis are the ammonium permeases (the nitrogen availability sensor candidate), ureases (a nitrogen-scavenging enzyme) and GATA transcription factors (global regulators of nitrogen catabolism). In certain species, the ammonium permease induces a morphological switch from yeast to invasive filamentous growth forms or infectious spores, while in others, urease is a bona fide virulence factor. In all species studied thus far, transcription of the ammonium permease and urease-encoding genes is modulated by GATA factors. Fungal pathogens therefore integrate the expression of different virulence-associated phenotypes into the regulatory network controlling nitrogen catabolism.
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Affiliation(s)
- I Russel Lee
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Qld, Australia
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Youngchim S, Nosanchuk JD, Pornsuwan S, Kajiwara S, Vanittanakom N. The role of L-DOPA on melanization and mycelial production in Malassezia furfur. PLoS One 2013; 8:e63764. [PMID: 23762233 PMCID: PMC3676409 DOI: 10.1371/journal.pone.0063764] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Accepted: 04/05/2013] [Indexed: 11/18/2022] Open
Abstract
Melanins are synthesized by organisms of all biological kingdoms and comprise a heterogeneous class of natural pigments. Certain of these polymers have been implicated in the pathogenesis of several important human fungal pathogens. This study investigated whether the fungal skin pathogen Malassezia furfur produces melanin or melanin-like compounds. A melanin-binding monoclonal antibody (MAb) labelled in vitro cultivated yeast cells of M. furfur. In addition, melanization of Malassezia yeasts and hyphae was detected by anti-melanin MAb in scrapings from patients with pityriasis versicolor. Treatment of Malassezia yeasts with proteolytic enzymes, denaturant and concentrated hot acid yielded dark particles and electron spin resonance spectroscopy revealed that these particles contained a stable free radical compound, consistent with their identification as melanins. Malassezia yeasts required phenolic compounds, such as L-DOPA, in order to synthesize melanin. L-DOPA also triggered hyphal formation in vitro when combined with kojic acid, a tyrosinase inhibitor, in a dose-dependent manner. In this respect, L-DOPA is thought to be an essential substance that is linked to both melanization and yeast-mycelial transformation in M. furfur. In summary, M. furfur can produce melanin or melanin-like compounds in vitro and in vivo, and the DOPA melanin pathway is involved in cell wall melanization.
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Affiliation(s)
- Sirida Youngchim
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
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40
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Yang L, Gao F, Shang L, Zhan J, McDonald BA. Association between virulence and triazole tolerance in the phytopathogenic fungus Mycosphaerella graminicola. PLoS One 2013; 8:e59568. [PMID: 23555044 PMCID: PMC3598747 DOI: 10.1371/journal.pone.0059568] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Accepted: 02/19/2013] [Indexed: 01/28/2023] Open
Abstract
Host resistance and synthetic antimicrobials such as fungicides are two of the main approaches used to control plant diseases in conventional agriculture. Although pathogens often evolve to overcome host resistance and antimicrobials, the majority of reports have involved qualitative host - pathogen interactions or antimicrobials targeting a single pathogen protein or metabolic pathway. Studies that consider jointly the evolution of virulence, defined as the degree of damage caused to a host by parasite infection, and antimicrobial resistance are rare. Here we compared virulence and fungicide tolerance in the fungal pathogen Mycosphaerella graminicola sampled from wheat fields across three continents and found a positive correlation between virulence and tolerance to a triazole fungicide. We also found that quantitative host resistance selected for higher pathogen virulence. The possible mechanisms responsible for these observations and their consequences for sustainable disease management are discussed.
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Affiliation(s)
- Lina Yang
- Key Lab for Biopesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, Fujian, People's Republic of China
- Laboratory of Plant Virology of Fujian Province, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, People's Republic of China
| | - Fangluan Gao
- Laboratory of Plant Virology of Fujian Province, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, People's Republic of China
| | - Liping Shang
- Laboratory of Plant Virology of Fujian Province, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, People's Republic of China
| | - Jiasui Zhan
- Key Lab for Biopesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, Fujian, People's Republic of China
- Laboratory of Plant Virology of Fujian Province, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, People's Republic of China
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Eisenman HC, Chow SK, Tsé KK, McClelland EE, Casadevall A. The effect of L-DOPA on Cryptococcus neoformans growth and gene expression. Virulence 2011; 2:329-36. [PMID: 21705857 DOI: 10.4161/viru.2.4.16136] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Cryptococcus neoformans is unusual among melanotic fungi in that it requires an exogenous supply of precursor to synthesize melanin. C. neoformans melanizes during mammalian infection in a process that presumably uses host-supplied compounds such as catecholamines. L-3,4-dihydroxyphenylalanine (L-DOPA) is a natural catecholamine that is frequently used to induce melanization in C. neoformans and L-DOPA-melanized cryptococci manifest resistance to radiation, phagocytosis, detergents and heavy metals. Given that C. neoformans needs exogenous substrate for melanization one question in the field is the extent to which melanin-associated phenotypes reflect the presence of melanin or metabolic changes in response to substrates. In this study we analyze the response of C. neoformans to L-DOPA with respect to melanization, gene expression and metabolic incorporation. Increasing the concentration of L-DOPA promotes melanin formation up to concentrations > 1 mM, after which toxicity is apparent as manifested by reduced growth. The timing of C. neoformans cells to melanization is affected by growth phase and cell density. Remarkably, growth of C. neoformans in the presence of L-DOPA results in the induction of relatively few genes, most of which could be related to stress metabolism. We interpret these results to suggest that the biological effects associated with melanization after growth in L-DOPA are largely due to the presence of the pigment. This in turn provides strong support for the view that melanin contributes to virulence directly through its presence in the cell wall.
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Youngchim S, Pornsuwan S, Nosanchuk JD, Dankai W, Vanittanakom N. Melanogenesis in dermatophyte species in vitro and during infection. MICROBIOLOGY-SGM 2011; 157:2348-2356. [PMID: 21565930 DOI: 10.1099/mic.0.047928-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Dermatophytes are keratinophilic fungi that are the most common cause of fungal skin infections worldwide. Melanin has been isolated from several important human fungal pathogens, and the polymeric pigment is now recognized as an important virulence determinant. This study investigated whether dermatophytes, including Trichophyton rubrum, Trichophyton mentagrophytes, Epidermophyton floccosum and Microsporum gypseum, produce melanin or melanin-like compounds in vitro and during infection. Digestion of the pigmented microconidia and macroconidia of dermatophytes with proteolytic enzymes, denaturant and hot concentrated acid yielded dark particles that retained the size and shape of the original fungal cells. Electron spin resonance spectroscopy revealed that particles derived from pigmented conidia contained a stable free radical signal, consistent with the pigments being a melanin. Immunofluorescence analysis demonstrated reactivity of a melanin-binding mAb with the pigmented conidia and hyphae, as well as the isolate particles. Laccase, an enzyme involved in melanization, was detected in the dermatophytes by an agar plate assay using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) as the substrate. Skin scrapings from patients with dermatophytoses contained septate hyphae and arthrospores that were reactive with the melanin-binding mAb. These findings indicate that dermatophytes can produce melanin or melanin-like compounds in vitro and during infection. Based on what is known about the function of melanin as a virulence factor of other pathogenic fungi, this pigment may have a similar role in the pathogenesis of dermatophytic diseases.
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Affiliation(s)
- Sirida Youngchim
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Thailand
| | - Soraya Pornsuwan
- Department of Physical Chemistry, Faculty of Science, Mahidol University, Thailand
| | - Joshua D Nosanchuk
- Department of Medicine (Infectious Diseases), Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Wiyada Dankai
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Thailand
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Abstract
Melanized or dematiaceous fungi are associated with a wide variety of infectious syndromes, including chromoblastomycosis, mycetoma, and phaeohyphomycosis. [corrected]. Many are soil organisms and are generally distributed worldwide, though certain species appear to have restricted geographic ranges. Though they are uncommon causes of disease, melanized fungi have been increasingly recognized as important pathogens, with most reports occurring in the past 20 years. The spectrum of diseases with which they are associated has also broadened and includes allergic disease, superficial and deep local infections, pneumonia, brain abscess, and disseminated infection. For some infections in immunocompetent individuals, such as allergic fungal sinusitis and brain abscess, they are among the most common etiologic fungi. Melanin is a likely virulence factor for these fungi. Diagnosis relies on careful microscopic and pathological examination, as well as clinical assessment of the patient, as these fungi are often considered contaminants. Therapy varies depending upon the clinical syndrome. Local infection may be cured with excision alone, while systemic disease is often refractory to therapy. Triazoles such as voriconazole, posaconazole, and itraconazole have the most consistent in vitro activity. Further studies are needed to better understand the pathogenesis and optimal treatment of these uncommon infections.
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44
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Gupta G, Fries BC. Variability of phenotypic traits in Cryptococcus varieties and species and the resulting implications for pathogenesis. Future Microbiol 2010; 5:775-87. [PMID: 20441549 DOI: 10.2217/fmb.10.44] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Variability of phenotypic characteristics in Cryptococcus neoformans var. grubii and var. neoformans as well as Cryptococcus gattii can have diverse effects on the virulence of these fungi and are thus important for pathogenesis. This article summarizes the diverse phenotypic changes that these fungi can manifest. We divide changes into those that affect the entire fungal population and are predominantly induced by environmental signals, and those that involve subpopulations of the fungal population and have to be selected. Last, the article summarizes the experimental evidence that epitopes on the polysaccharide capsule also vary, which may have implications for the pathogenesis as these findings would further diversify the fungal population.
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Affiliation(s)
- Gunjan Gupta
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, USA
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45
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Zaragoza O, García-Rodas R, Nosanchuk JD, Cuenca-Estrella M, Rodríguez-Tudela JL, Casadevall A. Fungal cell gigantism during mammalian infection. PLoS Pathog 2010; 6:e1000945. [PMID: 20585557 PMCID: PMC2887474 DOI: 10.1371/journal.ppat.1000945] [Citation(s) in RCA: 213] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Accepted: 05/07/2010] [Indexed: 02/07/2023] Open
Abstract
The interaction between fungal pathogens with the host frequently results in morphological changes, such as hyphae formation. The encapsulated pathogenic fungus Cryptococcus neoformans is not considered a dimorphic fungus, and is predominantly found in host tissues as round yeast cells. However, there is a specific morphological change associated with cryptococcal infection that involves an increase in capsule volume. We now report another morphological change whereby gigantic cells are formed in tissue. The paper reports the phenotypic characterization of giant cells isolated from infected mice and the cellular changes associated with giant cell formation. C. neoformans infection in mice resulted in the appearance of giant cells with cell bodies up to 30 microm in diameter and capsules resistant to stripping with gamma-radiation and organic solvents. The proportion of giant cells ranged from 10 to 80% of the total lung fungal burden, depending on infection time, individual mice, and correlated with the type of immune response. When placed on agar, giant cells budded to produce small daughter cells that traversed the capsule of the mother cell at the speed of 20-50 m/h. Giant cells with dimensions that approximated those in vivo were observed in vitro after prolonged culture in minimal media, and were the oldest in the culture, suggesting that giant cell formation is an aging-dependent phenomenon. Giant cells recovered from mice displayed polyploidy, suggesting a mechanism by which gigantism results from cell cycle progression without cell fission. Giant cell formation was dependent on cAMP, but not on Ras1. Real-time imaging showed that giant cells were engaged, but not engulfed by phagocytic cells. We describe a remarkable new strategy for C. neoformans to evade the immune response by enlarging cell size, and suggest that gigantism results from replication without fission, a phenomenon that may also occur with other fungal pathogens.
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MESH Headings
- Animals
- Cell Proliferation
- Cryptococcosis/immunology
- Cryptococcosis/microbiology
- Cryptococcosis/pathology
- Cryptococcus neoformans/growth & development
- Cryptococcus neoformans/pathogenicity
- Cryptococcus neoformans/radiation effects
- DNA, Fungal/genetics
- Female
- Fluorescent Antibody Technique
- Gamma Rays
- Gigantism/immunology
- Gigantism/microbiology
- Lung Diseases, Fungal/immunology
- Lung Diseases, Fungal/microbiology
- Lung Diseases, Fungal/pathology
- Macrophages, Alveolar/immunology
- Macrophages, Alveolar/microbiology
- Macrophages, Alveolar/pathology
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Oxidative Stress
- Phagosomes/immunology
- Phagosomes/microbiology
- Phagosomes/pathology
- RNA, Messenger/genetics
- Reverse Transcriptase Polymerase Chain Reaction
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Affiliation(s)
- Oscar Zaragoza
- Servicio de Micología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain.
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Silva MBD, Thomaz L, Marques AF, Svidzinski AE, Nosanchuk JD, Casadevall A, Travassos LR, Taborda CP. Resistance of melanized yeast cells of Paracoccidioides brasiliensis to antimicrobial oxidants and inhibition of phagocytosis using carbohydrates and monoclonal antibody to CD18. Mem Inst Oswaldo Cruz 2010; 104:644-8. [PMID: 19722091 DOI: 10.1590/s0074-02762009000400019] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2008] [Accepted: 03/04/2009] [Indexed: 11/22/2022] Open
Abstract
Paracoccidioides brasiliensis, a thermal dimorphic fungal pathogen, produces a melanin-like pigment in vitro and in vivo. We investigated the involvement of carbohydrates and monoclonal antibody to CD18, on phagocytosis inhibition, involving macrophage receptors and the resistance of melanized fungal cells to chemically generated nitric oxide (NO), reactive oxygen species (ROS), hypochlorite and H2O2. Our results demonstrate that melanized yeast cells were more resistant than nonmelanized yeast cells to chemically generated NO, ROS, hypochlorite and H2O2, in vitro. Phagocytosis of melanized yeast cells was virtually abolished when mannan, N-acetyl glucosamine and anti-CD18 antibody were added together in this system. Intratracheal infection of BALB/c mice, with melanized yeast cells, resulted in higher lung colony forming units, when compared to nonmelanized yeast cells. Therefore, melanin is a virulence factor of P. brasiliensis.
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Affiliation(s)
- Marcelo Barbosa da Silva
- Departamento de Microbiologia, Laboratório de Micologia Médica - LIM53 - Hospital de Clínicas, Faculdade de Medicina, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brasil
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Loussert C, Schmitt C, Prevost MC, Balloy V, Fadel E, Philippe B, Kauffmann-Lacroix C, Latgé JP, Beauvais A. In vivo biofilm composition of Aspergillus fumigatus. Cell Microbiol 2009; 12:405-10. [PMID: 19889082 DOI: 10.1111/j.1462-5822.2009.01409.x] [Citation(s) in RCA: 182] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The in vivo composition of the mycelial extracellular matrix (ECM) of Aspergillus fumigatus during host invasion is reported here for the first time. A new galactosaminogalactan and the galactomannan were the major polysaccharides of the in vivo ECM. The composition of the ECM in vivo varied with the aspergillosis pathologies.
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Affiliation(s)
- Céline Loussert
- Electron Microscopy Platform, Institut Pasteur, Paris, France
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Abstract
Cryptococcus neoformans and Cryptococcus gattii are the cause of life-threatening meningoencephalitis in immunocompromised and immunocompetent individuals respectively. The increasing incidence of cryptococcal infection as a result of the AIDS epidemic, the recent emergence of a hypervirulent cryptococcal strain in Canada and the fact that mortality from cryptococcal disease remains high have stimulated intensive research into this organism. Here we outline recent advances in our understanding of C. neoformans and C. gattii, including intraspecific complexity, virulence factors, and key signaling pathways. We discuss the molecular basis of cryptococcal virulence and the interaction between these pathogens and the host immune system. Finally, we discuss future challenges in the study and treatment of cryptococcosis.
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Affiliation(s)
- Hansong Ma
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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49
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Schiave LA, Pedroso RS, Candido RC, Roberts DW, Braga GUL. Variability in UVB tolerances of melanized and nonmelanized cells of Cryptococcus neoformans and C. laurentii. Photochem Photobiol 2008; 85:205-13. [PMID: 18764906 DOI: 10.1111/j.1751-1097.2008.00418.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Solar radiation is one of the major factors responsible for the control of fungus populations in the environment. Inactivation by UVA and UVB radiation is especially important for the control of fungi that disperse infective units through the air, including fungi such as Cryptococcus spp. that infect their vertebrate hosts by inhalation. Cryptococcus neoformans produces melanin in the presence of certain exogenous substrates such as l-3,4 dihydroxyphenylalanine and melanization may protect the fungus against biotic and abiotic environmental factors. In the present study, we investigated the effect of exposure to an UVB irradiance of 1000 mW m(-2) (biologically effective weighted irradiance) on the survival of melanized and nonmelanized cells of four strains of C. neoformans and four strains of C. laurentii. The relative survival (survival of cells exposed to radiation in relation to cells not exposed) of cells grown 2, 4, 6 or 8 days on medium with or without L-dopa was determined after exposure to UVB doses of 1.8 and 3.6 kJ m(-2). Both the irradiance spectrum and the intensities of those doses are environmentally realistic, and, in fact, occur routinely during summer months in temperate regions. Differences in tolerance to UVB radiation were observed between the C. neoformans and C. laurentii strains. The C. neoformans strains were more susceptible to UVB radiation than the C. laurentii strains. In C. neoformans, differences in tolerance to radiation were observed during development of both melanized and nonmelanized cells. For most treatments (strain, time of growth and UVB dose), there were virtually no differences in tolerances between melanized and nonmelanized cells, but when differences occurred they were smaller than those previously observed with UVC. In tests with two strains of C. laurentii, there was no difference in tolerance to UVB radiation between melanized and nonmelanized cells during 8 days of culture; and in tests with four strains for less culture time (4 days) there were no significant differences in tolerance between melanized and nonmelanized cells of any strain of this species.
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Affiliation(s)
- Letícia A Schiave
- Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
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Abstract
Cryptococcus neoformans is a yeastlike fungus that causes a lethal meningoencephalitis in a broad spectrum of immunocompromised patients and has become the most common cause of meningitis due to AIDS-related infections in Africa. Key to the development of new agents to control and prevent this infection is the identification of cellular mechanisms required for pathogenesis. Survival of the fungus within the hostile and nutrient-deprived environments of the host has recently been shown to depend on the induction of autophagy, whereby the cell recycles nutrients by slowly digesting itself in a regulated fashion. Further study of the role of autophagy during infection by C. neoformans requires the use of markers of autophagy that are specially adapted to the fungus within the mammalian host.
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