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Kappel L, Yu L, Escobar C, Marcianò D, Srivastava V, Bulone V, Gruber S. A comparative cell wall analysis of Trichoderma spp. confirms a conserved polysaccharide scaffold and suggests an important role for chitosan in mycoparasitism. Microbiol Spectr 2024; 12:e0349523. [PMID: 38916333 PMCID: PMC11302013 DOI: 10.1128/spectrum.03495-23] [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: 11/15/2023] [Accepted: 05/14/2024] [Indexed: 06/26/2024] Open
Abstract
Fungal cell walls are dynamic extracellular matrices that enable efficient adaptation to changing environments. While the cell wall compositions of yeasts, human, and plant pathogenic fungi have been studied to some extent, the cell walls of mycoparasites remain poorly characterized. Trichoderma species comprise a diverse group of soil fungi with different survival strategies and lifestyles. The comparative study of cell wall carbohydrate-active enzymes in 13 Trichoderma spp. revealed that the types of enzymes involved in chitin and chitosan metabolism are phylogenetically distant between mycoparasitic and saprotrophic species. Here, we compare the carbohydrate composition and function of the cell wall of a saprotrophic strain Trichoderma reesei with that of the mycoparasitic, biological control agent Trichoderma atroviride. Monosaccharide and glycosidic linkage analyses as well as dual in situ interaction assays showed that the cell wall polysaccharide composition is conserved between both species, except for the amounts of chitin detected. The results suggest that the observed accumulation of chitosan during mycoparasitism may prevent host recognition. Remarkably, Trichoderma atroviride undergoes dynamic cell wall adaptations during both vegetative development and mycoparasitism, which appears to be confirmed by an evolutionarily expanded group of specialized enzymes. Overall, our analyses support the notion that habitat specialization is reflected in cell wall architecture and that plastic chitin remodeling may confer an advantage to mycoparasites, ultimately enabling the successful invasion and parasitism of plant pathogens. This information may potentially be exploited for the control of crop diseases using biological agents. IMPORTANCE Trichoderma species are emerging model fungi for the development of biocontrol agents and are used in industrial biotechnology as efficient enzyme producers. Fungal cell walls are complex structures that differ in carbohydrate, protein, and enzyme composition across taxa. Here, we present a chemical characterization of the cell walls of two Trichoderma spp., namely the predominantly saprotrophic Trichoderma reesei and the mycoparasite Trichoderma atroviride. Chemical profiling revealed that Trichoderma spp. remodel their cell wall to adapt to particular lifestyles, with dynamic changes during vegetative development. Importantly, we found that chitosan accumulation during mycoparasitism of a fungal host emerged as a sophisticated strategy underpinning an effective attack. These insights shed light on the molecular mechanisms that allow mycoparasites to overcome host defenses and can be exploited to improve the application of T. atroviride in biological pest control. Moreover, our results provide valuable information for targeting the fungal cell wall for therapeutic purposes.
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Affiliation(s)
- Lisa Kappel
- Department of Bioengineering, University of Applied Sciences, Vienna, Austria
- Department of Microbiology, University of Innsbruck, Innsbruck, Austria
| | - Long Yu
- School of Agriculture, Food and Wine, The University of Adelaide, Adelaide, Australia
| | - Carolina Escobar
- Department of Bioengineering, University of Applied Sciences, Vienna, Austria
- Department of Microbiology, University of Innsbruck, Innsbruck, Austria
| | - Demetrio Marcianò
- Department of Agricultural and Environmental Sciences, via Celoria 2, Milan, Italy
| | - Vaibhav Srivastava
- Division of Glycoscience, Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, AlbaNova University Centre, Stockholm, Sweden
| | - Vincent Bulone
- School of Agriculture, Food and Wine, The University of Adelaide, Adelaide, Australia
- Division of Glycoscience, Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, AlbaNova University Centre, Stockholm, Sweden
| | - Sabine Gruber
- Department of Bioengineering, University of Applied Sciences, Vienna, Austria
- Department of Microbiology, University of Innsbruck, Innsbruck, Austria
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Li Y, Chadwick B, Pham T, Xie X, Lin X. Aspartyl peptidase May1 induces host inflammatory response by altering cell wall composition in the fungal pathogen Cryptococcus neoformans. mBio 2024; 15:e0092024. [PMID: 38742885 PMCID: PMC11237595 DOI: 10.1128/mbio.00920-24] [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: 03/28/2024] [Accepted: 04/09/2024] [Indexed: 05/16/2024] Open
Abstract
Cryptococcus neoformans causes cryptococcal meningoencephalitis, a disease that kills more than 180,000 people annually. Contributing to its success as a fungal pathogen is its cell wall surrounded by a capsule. When the cryptococcal cell wall is compromised, exposed pathogen-associated molecular pattern molecules (PAMPs) could trigger host recognition and initiate attack against this fungus. Thus, cell wall composition and structure are tightly regulated. The cryptococcal cell wall is unusual in that chitosan, the acetylated form of chitin, is predominant over chitin and is essential for virulence. Recently, it was shown that acidic pH weakens the cell wall and increases exposure of PAMPs partly due to decreased chitosan levels. However, the molecular mechanism responsible for the cell wall remodeling in acidic pH is unknown. In this study, by screening for genes involved in cryptococcal tolerance to high levels of CO2, we serendipitously discovered that the aspartyl peptidase May1 contributes to cryptococcal sensitivity to high levels of CO2 due to acidification of unbuffered media. Overexpression of MAY1 increases the cryptococcal cell size and elevates PAMP exposure, causing a hyper-inflammatory response in the host while MAY1 deletion does the opposite. We discovered that May1 weakens the cell wall and reduces the chitosan level, partly due to its involvement in the degradation of Chs3, the sole chitin synthase that supplies chitin to be converted to chitosan. Consistently, overexpression of CHS3 largely rescues the phenotype of MAY1oe in acidic media. Collectively, we demonstrate that May1 remodels the cryptococcal cell wall in acidic pH by reducing chitosan levels through its influence on Chs3. IMPORTANCE The fungal cell wall is a dynamic structure, monitoring and responding to internal and external stimuli. It provides a formidable armor to the fungus. However, in a weakened state, the cell wall also triggers host immune attack when PAMPs, including glucan, chitin, and mannoproteins, are exposed. In this work, we found that the aspartyl peptidase May1 impairs the cell wall of Cryptococcus neoformans and increases the exposure of PAMPs in the acidic environment by reducing the chitosan level. Under acidic conditions, May1 is involved in the degradation of the chitin synthase Chs3, which supplies chitin to be deacetylated to chitosan. Consistently, the severe deficiency of chitosan in acidic pH can be rescued by overexpressing CHS3. These findings improve our understanding of cell wall remodeling and reveal a potential target to compromise the cell wall integrity in this important fungal pathogen.
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Affiliation(s)
- Yeqi Li
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Benjamin Chadwick
- Department of Plant Biology, University of Georgia, Athens, Georgia, USA
| | - Tuyetnhu Pham
- Department of Plant Biology, University of Georgia, Athens, Georgia, USA
| | - Xiaofeng Xie
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Xiaorong Lin
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
- Department of Plant Biology, University of Georgia, Athens, Georgia, USA
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Tong L, Li Y, Lou X, Wang B, Jin C, Fang W. Powerful cell wall biomass degradation enzymatic system from saprotrophic Aspergillus fumigatus. Cell Surf 2024; 11:100126. [PMID: 38827922 PMCID: PMC11143905 DOI: 10.1016/j.tcsw.2024.100126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 05/08/2024] [Accepted: 05/15/2024] [Indexed: 06/05/2024] Open
Abstract
Cell wall biomass, Earth's most abundant natural resource, holds significant potential for sustainable biofuel production. Composed of cellulose, hemicellulose, lignin, pectin, and other polymers, the plant cell wall provides essential structural support to diverse organisms in nature. In contrast, non-plant species like insects, crustaceans, and fungi rely on chitin as their primary structural polysaccharide. The saprophytic fungus Aspergillus fumigatus has been widely recognized for its adaptability to various environmental conditions. It achieves this by secreting different cell wall biomass degradation enzymes to obtain essential nutrients. This review compiles a comprehensive collection of cell wall degradation enzymes derived from A. fumigatus, including cellulases, hemicellulases, various chitin degradation enzymes, and other polymer degradation enzymes. Notably, these enzymes exhibit biochemical characteristics such as temperature tolerance or acid adaptability, indicating their potential applications across a spectrum of industries.
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Affiliation(s)
- Lige Tong
- National Key Laboratory of Non-food Biomass Energy Technology, Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China
| | - Yunaying Li
- National Key Laboratory of Non-food Biomass Energy Technology, Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China
- College of Life Sciences, Hebei Innovation Center for Bioengineering and Biotechnology, Institute of Life Sciences and Green Development, Baoding, Hebei, China
| | - Xinke Lou
- National Key Laboratory of Non-food Biomass Energy Technology, Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China
- College of Life Sciences, Hebei Innovation Center for Bioengineering and Biotechnology, Institute of Life Sciences and Green Development, Baoding, Hebei, China
| | - Bin Wang
- National Key Laboratory of Non-food Biomass Energy Technology, Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China
| | - Cheng Jin
- National Key Laboratory of Non-food Biomass Energy Technology, Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Wenxia Fang
- National Key Laboratory of Non-food Biomass Energy Technology, Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China
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Zhang X, Wen M, Li G, Wang S. Chitin Deacetylase Homologous Gene cda Contributes to Development and Aflatoxin Synthesis in Aspergillus flavus. Toxins (Basel) 2024; 16:217. [PMID: 38787069 PMCID: PMC11125919 DOI: 10.3390/toxins16050217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 04/25/2024] [Accepted: 04/26/2024] [Indexed: 05/25/2024] Open
Abstract
The fungal cell wall serves as the primary interface between fungi and their external environment, providing protection and facilitating interactions with the surroundings. Chitin is a vital structural element in fungal cell wall. Chitin deacetylase (CDA) can transform chitin into chitosan through deacetylation, providing various biological functions across fungal species. Although this modification is widespread in fungi, the biological functions of CDA enzymes in Aspergillus flavus remain largely unexplored. In this study, we aimed to investigate the biofunctions of the CDA family in A. flavus. The A. flavus genome contains six annotated putative chitin deacetylases. We constructed knockout strains targeting each member of the CDA family, including Δcda1, Δcda2, Δcda3, Δcda4, Δcda5, and Δcda6. Functional analyses revealed that the deletion of CDA family members neither significantly affects the chitin content nor exhibits the expected chitin deacetylation function in A. flavus. However, the Δcda6 strain displayed distinct phenotypic characteristics compared to the wild-type (WT), including an increased conidia count, decreased mycelium production, heightened aflatoxin production, and impaired seed colonization. Subcellular localization experiments indicated the cellular localization of CDA6 protein within the cell wall of A. flavus filaments. Moreover, our findings highlight the significance of the CBD1 and CBD2 structural domains in mediating the functional role of the CDA6 protein. Overall, we analyzed the gene functions of CDA family in A. flavus, which contribute to a deeper understanding of the mechanisms underlying aflatoxin contamination and lay the groundwork for potential biocontrol strategies targeting A. flavus.
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Affiliation(s)
| | | | | | - Shihua Wang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic, Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (X.Z.); (M.W.); (G.L.)
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Mapuranga J, Chang J, Li H, Zhang Y, Li R, Song L, Zhang N, Yang W. The molecular structure, biological roles, and inhibition of plant pathogenic fungal chitin deacetylases. FRONTIERS IN PLANT SCIENCE 2024; 14:1335646. [PMID: 38264029 PMCID: PMC10803567 DOI: 10.3389/fpls.2023.1335646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 12/18/2023] [Indexed: 01/25/2024]
Abstract
Chitin/polysaccharide deacetylases belong to the carbohydrate esterases family 4 (CE4 enzymes). They play a crucial role in modifying the physiochemical characteristics of structural polysaccharides and are also involved in a wide range of biological processes such as fungal autolysis, spore formation, cell wall formation and integrity, and germling adhesion. These enzymes are mostly common in fungi, marine bacteria, and a limited number of insects. They facilitate the deacetylation of chitin which is a structural biopolymer that is abundantly found in fungal cell walls and spores and also in the cuticle and peritrophic matrices of insects. The deacetylases exhibit specificity towards a substrate containing a sequence of four GlcNAc units, with one of these units being subjected to deacetylation. Chitin deacetylation results in the formation of chitosan, which is a poor substrate for host plant chitinases, therefore it can suppress the host immune response triggered by fungal pathogens and enhance pathogen virulence and colonization. This review discusses plant pathogenic fungal chitin/polysaccharide deacetylases including their structure, substrate specificity, biological roles and some recently discovered chitin deacetylase inhibitors that can help to mitigate plant fungal diseases. This review provides fundamental knowledge that will undoubtedly lead to the rational design of novel inhibitors that target pathogenic fungal chitin deacetylases, which will also aid in the management of plant diseases, thereby safeguarding global food security.
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Affiliation(s)
| | | | | | | | | | | | | | - Wenxiang Yang
- College of Plant Protection, Technological Innovation Center for Biological Control of Plant Diseases and Insect Pests of Hebei Province, Hebei Agricultural University, Baoding, China
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Upadhya R, Probst C, Alspaugh JA, Lodge JK. Measuring Stress Phenotypes in Cryptococcus neoformans. Methods Mol Biol 2024; 2775:277-303. [PMID: 38758325 DOI: 10.1007/978-1-0716-3722-7_19] [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
Cryptococcus neoformans is an opportunistic human fungal pathogen capable of surviving in a wide range of environments and hosts. It has been developed as a model organism to study fungal pathogenesis due to its fully sequenced haploid genome and optimized gene deletion and mutagenesis protocols. These methods have greatly aided in determining the relationship between Cryptococcus genotype and phenotype. Furthermore, the presence of congenic mata and matα strains associated with a defined sexual cycle has helped further understand cryptococcal biology. Several in vitro stress conditions have been optimized to closely mimic the stress that yeast encounter in the environment or within the infected host. These conditions have proven to be extremely useful in elucidating the role of several genes in allowing yeast to adapt and survive in hostile external environments. This chapter describes various in vitro stress conditions that could be used to test the sensitivity of different mutant strains, as well as the protocol for preparing them. We have also included a list of mutants that could be used as a positive control strain when testing the sensitivity of the desired strain to a specific stress.
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Affiliation(s)
- Rajendra Upadhya
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, USA.
| | - Corinna Probst
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, USA
- Department of Medicine, Duke University School of Medicine, Durham, NC, USA
| | - J Andrew Alspaugh
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, USA
- Department of Medicine, Duke University School of Medicine, Durham, NC, USA
| | - Jennifer K Lodge
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, USA
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de Andrade IB, Alves V, Pereira L, Miranda B, Corrêa-Junior D, Galdino Figueiredo-Carvalho MH, Santos MV, Almeida-Paes R, Frases S. Effect of rapamycin on Cryptococcus neoformans: cellular organization, biophysics and virulence factors. Future Microbiol 2023; 18:1061-1075. [PMID: 37721517 DOI: 10.2217/fmb-2023-0097] [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: 09/19/2023] Open
Abstract
Background: Cryptococcus neoformans is an opportunistic fungal pathogen that causes infections mainly in immunosuppressed individuals, such as transplant recipients. Aims: This study investigated the effects of rapamycin, an immunosuppressant drug, on the cellular organization, biophysical characteristics, and main virulence factors of C. neoformans. Methods: Morphological, structural, physicochemical and biophysical analyses of cells and secreted polysaccharides of the reference H99 C. neoformans strain were investigated under the effect of subinhibitory concentrations of rapamycin. Results: Rapamycin at a minimum inhibitory concentration of 2.5 μM reduced C. neoformans cell viability by 53%, decreased capsule, increased cell size, chitin and lipid body formation, and changed peptidase and urease activity. Conclusion: Further studies are needed to assess how rapamycin affects the virulence factors and pathogenicity of C. neoformans.
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Affiliation(s)
- Iara Bastos de Andrade
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Vinicius Alves
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Luiza Pereira
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Bruna Miranda
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Dario Corrêa-Junior
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | | | - Marcos Vinicius Santos
- Laboratório de Micologia, Instituto Nacional de Infectologia Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Rodrigo Almeida-Paes
- Laboratório de Micologia, Instituto Nacional de Infectologia Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
- Rede Micologia - FAPERJ, Rio de Janeiro, Brazil
| | - Susana Frases
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
- Rede Micologia - FAPERJ, Rio de Janeiro, Brazil
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Choy HL, Gaylord EA, Doering TL. Ergosterol distribution controls surface structure formation and fungal pathogenicity. mBio 2023; 14:e0135323. [PMID: 37409809 PMCID: PMC10470819 DOI: 10.1128/mbio.01353-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 06/01/2023] [Indexed: 07/07/2023] Open
Abstract
Ergosterol, the major sterol in fungal membranes, is critical for defining membrane fluidity and regulating cellular processes. Although ergosterol synthesis has been well defined in model yeast, little is known about sterol organization in the context of fungal pathogenesis. We identified a retrograde sterol transporter, Ysp2, in the opportunistic fungal pathogen Cryptococcus neoformans. We found that the lack of Ysp2 under host-mimicking conditions leads to abnormal accumulation of ergosterol at the plasma membrane, invagination of the plasma membrane, and malformation of the cell wall, which can be functionally rescued by inhibiting ergosterol synthesis with the antifungal drug fluconazole. We also observed that cells lacking Ysp2 mislocalize the cell surface protein Pma1 and have abnormally thin and permeable capsules. As a result of perturbed ergosterol distribution and its consequences, ysp2∆ cells cannot survive in physiologically relevant environments such as host phagocytes and are dramatically attenuated in virulence. These findings expand our knowledge of cryptococcal biology and underscore the importance of sterol homeostasis in fungal pathogenesis. IMPORTANCE Cryptococcus neoformans is an opportunistic fungal pathogen that kills over 100,000 people worldwide each year. Only three drugs are available to treat cryptococcosis, and these are variously limited by toxicity, availability, cost, and resistance. Ergosterol is the most abundant sterol in fungi and a key component in modulating membrane behavior. Two of the drugs used for cryptococcal infection, amphotericin B and fluconazole, target this lipid and its synthesis, highlighting its importance as a therapeutic target. We discovered a cryptococcal ergosterol transporter, Ysp2, and demonstrated its key roles in multiple aspects of cryptococcal biology and pathogenesis. These studies demonstrate the role of ergosterol homeostasis in C. neoformans virulence, deepen our understanding of a pathway with proven therapeutic importance, and open a new area of study.
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Affiliation(s)
- Hau Lam Choy
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Elizabeth A. Gaylord
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Tamara L. Doering
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
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Huang J, Lei J, Ge A, Xiao W, Xin C, Song Z, Zhang J. Antifungal Effect of Vitamin D 3 against Cryptococcus neoformans Coincides with Reduced Biofilm Formation, Compromised Cell Wall Integrity, and Increased Generation of Reactive Oxygen Species. J Fungi (Basel) 2023; 9:772. [PMID: 37504760 PMCID: PMC10381739 DOI: 10.3390/jof9070772] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 07/15/2023] [Accepted: 07/20/2023] [Indexed: 07/29/2023] Open
Abstract
Cryptococcus neoformans is an invasive fungus that causes both acute and chronic infections, especially in immunocompromised patients. Owing to the increase in the prevalence of drug-resistant pathogenic fungi and the limitations of current treatment strategies, drug repositioning has become a feasible strategy to accelerate the development of new drugs. In this study, the minimum inhibitory concentration of vitamin D3 (VD3) against C. neoformans was found to be 0.4 mg/mL by broth microdilution assay. The antifungal activities of VD3 were further verified by solid dilution assays and "time-kill" curves. The results showed that VD3 reduced fungal cell adhesion and hydrophobicity and inhibited biofilm formation at various developmental stages, as confirmed by crystal violet staining and the 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide assay. Fluorescence staining of cellular components and a stress susceptibility assay indicated that VD3 compromised cell integrity. Reverse transcription quantitative PCR demonstrated that VD3 treatment upregulated the expression of fungal genes related to cell wall synthesis (i.e., CDA3, CHS3, FKS1, and AGS1). Moreover, VD3 enhanced cell membrane permeability and caused the accumulation of intracellular reactive oxygen species. Finally, VD3 significantly reduced the tissue fungal burden and prolonged the survival of Galleria mellonella larvae infected with C. neoformans. These results showed that VD3 could exert significant antifungal activities both in vitro and in vivo, demonstrating its potential application in the treatment of cryptococcal infections.
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Affiliation(s)
- Jian Huang
- Public Center of Experimental Technology, School of Basic Medical Sciences, Southwest Medical University, Luzhou 646000, China
| | - Junwen Lei
- Public Center of Experimental Technology, School of Basic Medical Sciences, Southwest Medical University, Luzhou 646000, China
| | - Anni Ge
- Public Center of Experimental Technology, School of Basic Medical Sciences, Southwest Medical University, Luzhou 646000, China
| | - Wei Xiao
- Public Center of Experimental Technology, School of Basic Medical Sciences, Southwest Medical University, Luzhou 646000, China
| | - Caiyan Xin
- Public Center of Experimental Technology, School of Basic Medical Sciences, Southwest Medical University, Luzhou 646000, China
| | - Zhangyong Song
- Public Center of Experimental Technology, School of Basic Medical Sciences, Southwest Medical University, Luzhou 646000, China
| | - Jinping Zhang
- Public Center of Experimental Technology, School of Basic Medical Sciences, Southwest Medical University, Luzhou 646000, China
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Cong L, Chen C, Mao S, Han Z, Zhu Z, Li Y. Intestinal bacteria-a powerful weapon for fungal infections treatment. Front Cell Infect Microbiol 2023; 13:1187831. [PMID: 37333850 PMCID: PMC10272564 DOI: 10.3389/fcimb.2023.1187831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 05/22/2023] [Indexed: 06/20/2023] Open
Abstract
The morbidity and mortality of invasive fungal infections are rising gradually. In recent years, fungi have quietly evolved stronger defense capabilities and increased resistance to antibiotics, posing huge challenges to maintaining physical health. Therefore, developing new drugs and strategies to combat these invasive fungi is crucial. There are a large number of microorganisms in the intestinal tract of mammals, collectively referred to as intestinal microbiota. At the same time, these native microorganisms co-evolve with their hosts in symbiotic relationship. Recent researches have shown that some probiotics and intestinal symbiotic bacteria can inhibit the invasion and colonization of fungi. In this paper, we review the mechanism of some intestinal bacteria affecting the growth and invasion of fungi by targeting the virulence factors, quorum sensing system, secreting active metabolites or regulating the host anti-fungal immune response, so as to provide new strategies for resisting invasive fungal infection.
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Affiliation(s)
- Liu Cong
- School of Medical Technology, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Chaoqun Chen
- School of Medical Technology, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Shanshan Mao
- School of Medical Technology, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Zibing Han
- Department of Genetics, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Zuobin Zhu
- Department of Genetics, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Ying Li
- School of Medical Technology, Xuzhou Medical University, Xuzhou, Jiangsu, China
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Upadhya R, Lam WC, Hole CR, Vasselli JG, Lodge JK. Cell wall composition in Cryptococcus neoformans is media dependent and alters host response, inducing protective immunity. FRONTIERS IN FUNGAL BIOLOGY 2023; 4:1183291. [PMID: 37538303 PMCID: PMC10399910 DOI: 10.3389/ffunb.2023.1183291] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 08/05/2023]
Abstract
Introduction Cryptococcus neoformans is a basidiomycete fungus that can cause meningoencephalitis, especially in immunocompromised patients. Cryptococcus grows in many different media, although little attention has been paid to the role of growth conditions on the cryptococcal cell wall or on virulence. Objective The purpose of this study was to determine how different media influenced the amount of chitin and chitosan in the cell wall, which in turn impacted the cell wall architecture and host response. Methods Yeast extract, peptone, and dextrose (YPD) and yeast nitrogen base (YNB) are two commonly used media for growing Cryptococcus before use in in vitro or in vivo experiments. As a result, C. neoformans was grown in either YPD or YNB, which were either left unbuffered or buffered to pH 7 with MOPS. These cells were then labeled with cell wall-specific fluorescent probes to determine the amounts of various cell wall components. In addition, these cells were employed in animal virulence studies using the murine inhalation model of infection. Results We observed that the growth of wild-type C. neoformans KN99 significantly changes the pH of unbuffered media during growth. It raises the pH to 8.0 when grown in unbuffered YPD but lowers the pH to 2.0 when grown in unbuffered YNB (YNB-U). Importantly, the composition of the cell wall was substantially impacted by growth in different media. Cells grown in YNB-U exhibited a 90% reduction in chitosan, the deacetylated form of chitin, compared with cells grown in YPD. The decrease in pH and chitosan in the YNB-U-grown cells was associated with a significant increase in some pathogen-associated molecular patterns on the surface of cells compared with cells grown in YPD or YNB, pH 7. This altered cell wall architecture resulted in a significant reduction in virulence when tested using a murine model of infection. Furthermore, when heat-killed cells were used as the inoculum, KN99 cells grown in YNB-U caused an aberrant hyper-inflammatory response in the lungs, resulting in rapid animal death. In contrast, heat-killed KN99 cells grown in YNB, pH 7, caused little to no inflammatory response in the host lung, but, when used as a vaccine, they conferred a robust protective response against a subsequent challenge infection with the virulent KN99 cells. Conclusion These findings emphasize the importance of culture media and pH during growth in shaping the content and organization of the C. neoformans cell wall, as well as their impact on fungal virulence and the host response.
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Affiliation(s)
- Rajendra Upadhya
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, United States
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, United States
| | - Woei C. Lam
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, United States
| | - Camaron R. Hole
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, United States
| | - Joseph G. Vasselli
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, United States
| | - Jennifer K. Lodge
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, United States
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, United States
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12
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Ma LS, Tsai WL, Damei FA, Kalunke RM, Xu MY, Lin YH, Lee HC. Maize Antifungal Protein AFP1 Elevates Fungal Chitin Levels by Targeting Chitin Deacetylases and Other Glycoproteins. mBio 2023; 14:e0009323. [PMID: 36946727 PMCID: PMC10128019 DOI: 10.1128/mbio.00093-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023] Open
Abstract
Pathogenic fungi convert chitin to chitosan to evade plant perception and disarm chitin-triggered immune responses. Whether plants have evolved factors to counteract this evasion mechanism remains obscure. Here, we decipher the mechanism underlying the antifungal activity of maize secretory mannose-binding cysteine-rich receptor-like secreted protein (CRRSP), antifungal protein 1 (AFP1). AFP1 binds to multiple sites on the surface of sporidial cells, filaments, and germinated spores of the biotrophic fungus Ustilago maydis. It inhibits cell growth and budding, as well as spore germination. AFP1 promiscuously interacts with most chitin deacetylases (CDAs) by recognizing the conserved NodB domain to interfere with the enzyme activity. Deletion of O-mannosyltransferase 4 decreases protein mannosylation, which correlates with reduced AFP1 binding and antifungal activity, suggesting that AFP1 interacts with mannosylated proteins to exhibit an inhibitory effect. AFP1 also has extended inhibitory activity against Saccharomyces cerevisiae; however, AFP1 did not reduce binding to the double ΔΔcda1,2 mutant, suggesting the targets of AFP1 have expanded to other cell surface glycoproteins, probably facilitated by its mannose-binding property. Increasing chitin levels by modulating the activity of cell surface glycoproteins is a universal feature of AFP1 interacting with a broad spectrum of fungi to inhibit their growth. IMPORTANCE Plants alert immune systems by recognizing the fungal pathogen cell wall component chitin via pattern recognition cell surface receptors. Successful fungal pathogens escape the perception by deacetylating chitin to chitosan, which is also necessary for fungal cell development and virulence. Targeting glycoproteins that are associated with regulating chitin metabolism and maintaining cell wall morphogenesis presents an effective strategy to combat fungal pathogens by simultaneously altering cell wall plasticity, activating chitin-triggered immunity, and impairing fungal viability. Our study provides molecular insights into a plant DUF26 domain-containing secretory protein in warding off a broad range of fungal pathogens by acting on more than one glycoprotein target.
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Affiliation(s)
- Lay-Sun Ma
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Wei-Lun Tsai
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | | | - Raviraj M Kalunke
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Meng-Yun Xu
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Yu-Han Lin
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Hui-Chun Lee
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
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De Jesus DFF, De Freitas ALD, De Oliveira IM, De Almeida LC, Bastos RW, Spadari CDC, Melo ASDA, Santos DDA, Costa-Lotufo LV, Reis FCG, Rodrigues ML, Stefani HA, Ishida K. Organoselenium Has a Potent Fungicidal Effect on Cryptococcus neoformans and Inhibits the Virulence Factors. Antimicrob Agents Chemother 2023; 67:e0075922. [PMID: 36815840 PMCID: PMC10019174 DOI: 10.1128/aac.00759-22] [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: 05/30/2022] [Accepted: 01/14/2023] [Indexed: 02/24/2023] Open
Abstract
Cryptococcosis therapy is often limited by toxicity problems, antifungal tolerance, and high costs. Studies approaching chalcogen compounds, especially those containing selenium, have shown promising antifungal activity against pathogenic species. This work aimed to evaluate the in vitro and in vivo antifungal potential of organoselenium compounds against Cryptococcus neoformans. The lead compound LQA_78 had an inhibitory effect on C. neoformans planktonic cells and dispersed cells from mature biofilms at similar concentrations. The fungal growth inhibition led to an increase in budding cells arrested in the G2/M phase, but the compound did not significantly affect structural cell wall components or chitinase activity, an enzyme that regulates the dynamics of the cell wall. The compound also inhibited titan cell (Tc) and enlarged capsule yeast (NcC) growth and reduced the body diameter and capsule thickness associated with increased capsular permeability of both virulent morphotypes. LQA_78 also reduced fungal melanization through laccase activity inhibition. The fungicidal activity was observed at higher concentrations (16 to 64 μg/mL) and may be associated with augmented plasma membrane permeability, ROS production, and loss of mitochondrial membrane potential. While LQA_78 is a nonhemolytic compound, its cytotoxic effects were cell type dependent, exhibiting no toxicity on Galleria mellonella larvae at a dose ≤46.5 mg/kg. LQA_78 treatment of larvae infected with C. neoformans effectively reduced the fungal burden and inhibited virulent morphotype formation. To conclude, LQA_78 displays fungicidal action and inhibits virulence factors of C. neoformans. Our results highlight the potential use of LQA_78 as a lead molecule for developing novel pharmaceuticals for treating cryptococcosis.
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Affiliation(s)
| | | | | | | | - Rafael Wesley Bastos
- Center of Biosciences, Federal University of Rio Grande do Norte (UFRN), Natal, Brazil
| | | | | | - Daniel de Assis Santos
- Institute of Biomedical Sciences, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | | | - Flavia C. G. Reis
- Carlos Chagas Institute, Oswaldo Cruz Foundation, Curitiba, Brazil
- Center for Technological Development in Health (CDTS), Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Marcio L. Rodrigues
- Carlos Chagas Institute, Oswaldo Cruz Foundation, Curitiba, Brazil
- Institute of Microbiology Paulo de Góes, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | | | - Kelly Ishida
- Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, Brazil
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14
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Liu JH, Dong JC, Gao JJ, Li XP, Hu SJ, Li J, Hu WX, Zhao XY, Wang JJ, Qiu L. Three Chitin Deacetylase Family Members of Beauveria bassiana Modulate Asexual Reproduction and Virulence of Fungi by Mediating Chitin Metabolism and Affect Fungal Parasitism and Saprophytic Life. Microbiol Spectr 2023; 11:e0474822. [PMID: 36786652 PMCID: PMC10101055 DOI: 10.1128/spectrum.04748-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Accepted: 01/17/2023] [Indexed: 02/15/2023] Open
Abstract
As an important chitin-modifying enzyme, chitin deacetylase (CDA) has been characterized in many fungi, but its function in the entomopathogenic fungus Beauveria bassiana remains unclear. Three CDAs with conserved domains of the carbohydrate esterase 4 (CE-4) family were identified in B. bassiana. Disruption of CDA1 resulted in growth restriction of the fungus on medium with chitin as a carbon source or without a carbon source. Deletion of CDA1 and CDA2 led to defects in fungal conidial formation and conidial vitality compared with those of the wild type (WT), and the conidial yield decreased by 25.81% to 47.68%. Inactivation of three CDA genes resulted in a decrease of 20.23% to 27% in the blastospore yield. ΔCDA1 and ΔCDA3 showed 29.33% and 23.34% reductions in cuticular infection virulence, respectively. However, the CDA family may not contribute to hemocoel infection virulence. Additionally, the sporulation of the insect carcass showed that the three gene deletion mutants were 68.45%, 63.84%, and 56.65% less than WT. Penetration experiments with cicada wings and enzyme activity assays were used to further explore the effect of the fungus on chitin metabolism after gene deletion. Although the three gene deletion mutants penetrated the cicada wings successfully and continued to grow on the underlying medium, their colony sizes were reduced by 29.12% to 47.76%. The CDA enzyme activity of ΔCDA1 and ΔCDA3 decreased by 84.76% and 83.04%, respectively. These data showed that members of the CDA family play a different role in fungal growth, conidial quality, and virulence. IMPORTANCE In this study, we report the roles of CDA family in entomopathogenic fungus B. bassiana. Our results indicated that CDA modulates asexual development and regulates fungal virulence by altering chitin deacetylation and metabolic capacity. CDA affected the biological control potential and life history of B. bassiana by affecting its parasitic and saprophytic life. These findings provide novel insights into the roles of multiple CDA paralogues existing in fungal biocontrol agents.
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Affiliation(s)
- Jia-Hua Liu
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan, China
| | - Jing-Chong Dong
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan, China
| | - Jun-Jie Gao
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan, China
| | - Xin-Peng Li
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan, China
| | - Shun-Juan Hu
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan, China
| | - Juan Li
- School of Biological Science and Technology, University of Jinan, Jinan, China
| | - Wen-Xiao Hu
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan, China
| | - Xian-Yan Zhao
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan, China
| | - Juan-Juan Wang
- School of Biological Science and Technology, University of Jinan, Jinan, China
| | - Lei Qiu
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan, China
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15
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Urs MJ, Moerschbacher BM, Cord-Landwehr S. Quantitative enzymatic-mass spectrometric analysis of the chitinous polymers in fungal cell walls. Carbohydr Polym 2022; 301:120304. [DOI: 10.1016/j.carbpol.2022.120304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 10/29/2022] [Accepted: 10/31/2022] [Indexed: 11/06/2022]
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16
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Liang YY, Yan LQ, Tan MH, Li GH, Fang JH, Peng JY, Li KT. Isolation, characterization, and genome sequencing of a novel chitin deacetylase producing Bacillus aryabhattai TCI-16. Front Microbiol 2022; 13:999639. [PMID: 36171752 PMCID: PMC9511218 DOI: 10.3389/fmicb.2022.999639] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 08/23/2022] [Indexed: 11/23/2022] Open
Abstract
Chitin deacetylase (CDA) is a chitin degradation enzyme that catalyzes the conversion of chitin to chitosan by the deacetylation of N-acetyl-D-glucosamine residues, playing an important role in the high-value utilization of waste chitin. The shells of shrimp and crab are rich in chitin, and mangroves are usually recognized as an active habitat to shrimp and crab. In the present study, a CDA-producing bacterium, strain TCI-16, was isolated and screened from the mangrove soil. Strain TCI-16 was identified and named as Bacillus aryabhattai TCI-16, and the maximum CDA activity in fermentation broth reached 120.35 ± 2.40 U/mL at 36 h of cultivation. Furthermore, the complete genome analysis of B. aryabhattai TCI-16 revealed the chitin-degrading enzyme system at genetic level, in which a total of 13 putative genes were associated with carbohydrate esterase 4 (CE4) family enzymes, including one gene coding CDA, seven genes encoding polysaccharide deacetylases, and five genes encoding peptidoglycan-N-acetyl glucosamine deacetylases. Amino acid sequence analysis showed that the predicted CDA of B. aryabhattai TCI-16 was composed of 236 amino acid residues with a molecular weight of 27.3 kDa, which possessed a conserved CDA active like the known CDAs. However, the CDA of B. aryabhattai TCI-16 showed low homology (approximately 30%) with other microbial CDAs, and its phylogenetic tree belonged to a separate clade in bacteria, suggesting a high probability in structural novelty. In conclusion, the present study indicated that the novel CDA produced by B. aryabhattai TCI-16 might be a promising option for bioconversion of chitin to the value-added chitosan.
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Affiliation(s)
- Ying-yin Liang
- Guangdong Provincial Key Laboratory of Aquatic Product Processing and Safety, Guangdong Provincial Engineering Technology Research Center of Seafood, Guangdong Province Engineering Laboratory for Marine Biological Products, College of Food Science and Technology, Key Laboratory of Advanced Processing of Aquatic Product of Guangdong Higher Education Institution, Guangdong Ocean University, Zhanjiang, China
- Collaborative Innovation Center of Seafood Deep Processing, Dalian Polytechnic University, Dalian, China
| | - Lu-qi Yan
- Guangdong Provincial Key Laboratory of Aquatic Product Processing and Safety, Guangdong Provincial Engineering Technology Research Center of Seafood, Guangdong Province Engineering Laboratory for Marine Biological Products, College of Food Science and Technology, Key Laboratory of Advanced Processing of Aquatic Product of Guangdong Higher Education Institution, Guangdong Ocean University, Zhanjiang, China
- Collaborative Innovation Center of Seafood Deep Processing, Dalian Polytechnic University, Dalian, China
| | - Ming-hui Tan
- Guangdong Provincial Key Laboratory of Aquatic Product Processing and Safety, Guangdong Provincial Engineering Technology Research Center of Seafood, Guangdong Province Engineering Laboratory for Marine Biological Products, College of Food Science and Technology, Key Laboratory of Advanced Processing of Aquatic Product of Guangdong Higher Education Institution, Guangdong Ocean University, Zhanjiang, China
- Collaborative Innovation Center of Seafood Deep Processing, Dalian Polytechnic University, Dalian, China
- *Correspondence: Ming-hui Tan,
| | - Gang-hui Li
- Guangdong Provincial Key Laboratory of Aquatic Product Processing and Safety, Guangdong Provincial Engineering Technology Research Center of Seafood, Guangdong Province Engineering Laboratory for Marine Biological Products, College of Food Science and Technology, Key Laboratory of Advanced Processing of Aquatic Product of Guangdong Higher Education Institution, Guangdong Ocean University, Zhanjiang, China
- Collaborative Innovation Center of Seafood Deep Processing, Dalian Polytechnic University, Dalian, China
| | - Jian-hao Fang
- Guangdong Provincial Key Laboratory of Aquatic Product Processing and Safety, Guangdong Provincial Engineering Technology Research Center of Seafood, Guangdong Province Engineering Laboratory for Marine Biological Products, College of Food Science and Technology, Key Laboratory of Advanced Processing of Aquatic Product of Guangdong Higher Education Institution, Guangdong Ocean University, Zhanjiang, China
- Collaborative Innovation Center of Seafood Deep Processing, Dalian Polytechnic University, Dalian, China
| | - Jie-ying Peng
- Guangdong Provincial Key Laboratory of Aquatic Product Processing and Safety, Guangdong Provincial Engineering Technology Research Center of Seafood, Guangdong Province Engineering Laboratory for Marine Biological Products, College of Food Science and Technology, Key Laboratory of Advanced Processing of Aquatic Product of Guangdong Higher Education Institution, Guangdong Ocean University, Zhanjiang, China
- Collaborative Innovation Center of Seafood Deep Processing, Dalian Polytechnic University, Dalian, China
| | - Kun-tai Li
- Guangdong Provincial Key Laboratory of Aquatic Product Processing and Safety, Guangdong Provincial Engineering Technology Research Center of Seafood, Guangdong Province Engineering Laboratory for Marine Biological Products, College of Food Science and Technology, Key Laboratory of Advanced Processing of Aquatic Product of Guangdong Higher Education Institution, Guangdong Ocean University, Zhanjiang, China
- Collaborative Innovation Center of Seafood Deep Processing, Dalian Polytechnic University, Dalian, China
- Kun-tai Li,
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17
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Abstract
Invasive fungal infections are emerging diseases that kill over 1.5 million people per year worldwide. With the increase of immunocompromised populations, the incidence of invasive fungal infections is expected to continue to rise. Vaccines for viral and bacterial infectious diseases have had a transformative impact on human health worldwide. However, no fungal vaccines are currently in clinical use. Recently, interest in fungal vaccines has grown significantly. One Candida vaccine has completed phase 2 clinical trials, and research on vaccines against coccidioidomycosis continues to advance. Additionally, multiple groups have discovered various Cryptococcus mutant strains that promote protective responses to subsequent challenge in mouse models. There has also been progress in antibody-mediated fungal vaccines. In this review, we highlight recent fungal vaccine research progress, outline the wealth of data generated, and summarize current research for both fungal biology and immunology studies relevant to fungal vaccine development. We also review technological advancements in vaccine development and highlight the future prospects of a human vaccine against invasive fungal infections.
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Affiliation(s)
- Amariliz Rivera
- Department of Pediatrics and Center for Immunity and Inflammation, Rutgers Biomedical and Health Sciences, Newark, New Jersey, USA;
| | - Jennifer Lodge
- Department of Molecular Microbiology, Washington University in St. Louis, St. Louis, Missouri, USA
- Current affiliation: Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina, USA;
| | - Chaoyang Xue
- Public Health Research Institute and Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers Biomedical and Health Sciences, Newark, New Jersey, USA;
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18
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Yang Y, Fan P, Liu J, Xie W, Liu N, Niu Z, Li Q, Song J, Tian Q, Bao Y, Wang H, Feng D. Thinopyrum intermedium TiAP1 interacts with a chitin deacetylase from Blumeria graminis f. sp. tritici and increases the resistance to Bgt in wheat. PLANT BIOTECHNOLOGY JOURNAL 2022; 20:454-467. [PMID: 34651397 PMCID: PMC8882775 DOI: 10.1111/pbi.13728] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 09/26/2021] [Accepted: 10/02/2021] [Indexed: 06/13/2023]
Abstract
The biotrophic fungal pathogen Blumeria graminis f. sp. tritici (Bgt) is a crucial factor causing reduction in global wheat production. Wild wheat relatives, for example Thinopyrum intermedium, is one of the wild-used parents in wheat disease-resistant breeding. From T. intermedium line, we identified the aspartic protease gene, TiAP1, which is involved in resistance against Bgt. TiAP1 is a secreted protein that accumulates in large amounts at the infection sites of Bgt and extends to the intercellular space. Yeast two-hybrid, luciferase complementation imaging and bimolecular florescent complimentary analysis showed that TiAP1 interacted with the chitin deacetylase (BgtCDA1) of Bgt. The yeast expression, purification and in vitro test confirmed the chitin deacetylase activity of BgtCDA1. The bombardment and VIGS-mediated host-induced gene silencing showed that BgtCDA1 promotes the invasion of Bgt. Transcriptome analysis showed the cell wall xylan metabolism, lignin biosynthesis-related and defence genes involved in the signal transduction were up-regulated in the transgenic TiAP1 wheat induced by Bgt. The TiAP1 in wheat may inactivate the deacetylation function of BgtCDA1, cause chitin oligomers expose to wheat chitin receptor, then trigger the wheat immune response to inhibit the growth and penetration of Bgt, and thereby enhance the resistance of wheat to pathogens.
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Affiliation(s)
- Yanlin Yang
- State Key Laboratory of Crop BiologyShandong Key Laboratory of Crop BiologyCollege of AgronomyShandong Agricultural UniversityTai’anChina
| | - Pan Fan
- State Key Laboratory of Crop BiologyShandong Key Laboratory of Crop BiologyCollege of AgronomyShandong Agricultural UniversityTai’anChina
| | - Jingxia Liu
- State Key Laboratory of Crop BiologyShandong Key Laboratory of Crop BiologyCollege of AgronomyShandong Agricultural UniversityTai’anChina
| | - Wenjun Xie
- Plant Defence Genetics LabDepartment of Plant and Environmental SciencesUniversity of CopenhagenFrederiksberg CDenmark
| | - Na Liu
- State Key Laboratory of Crop BiologyShandong Key Laboratory of Crop BiologyCollege of AgronomyShandong Agricultural UniversityTai’anChina
| | - Zubiao Niu
- State Key Laboratory of Crop BiologyShandong Key Laboratory of Crop BiologyCollege of AgronomyShandong Agricultural UniversityTai’anChina
| | - Quanquan Li
- State Key Laboratory of Crop BiologyShandong Key Laboratory of Crop BiologyCollege of AgronomyShandong Agricultural UniversityTai’anChina
| | - Jing Song
- State Key Laboratory of Crop BiologyShandong Key Laboratory of Crop BiologyCollege of AgronomyShandong Agricultural UniversityTai’anChina
| | - Qiuju Tian
- State Key Laboratory of Crop BiologyShandong Key Laboratory of Crop BiologyCollege of AgronomyShandong Agricultural UniversityTai’anChina
| | - Yinguang Bao
- State Key Laboratory of Crop BiologyShandong Key Laboratory of Crop BiologyCollege of AgronomyShandong Agricultural UniversityTai’anChina
| | - Honggang Wang
- State Key Laboratory of Crop BiologyShandong Key Laboratory of Crop BiologyCollege of AgronomyShandong Agricultural UniversityTai’anChina
| | - Deshun Feng
- State Key Laboratory of Crop BiologyShandong Key Laboratory of Crop BiologyCollege of AgronomyShandong Agricultural UniversityTai’anChina
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19
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Abstract
Systemic cryptococcosis is fatal without treatment. Globally, this disease kills 180,000 of the 225,000 infected people each year, even with the use of antifungal therapies. Currently, there is no vaccine to prevent cryptococcosis. Previously, we discovered that Znf2, a morphogenesis regulator that directs Cryptococcus yeast-to-hyphal transition, profoundly affects cryptococcal interaction with the host-overexpression of ZNF2 drives filamentous growth, attenuates cryptococcal virulence, and elicits protective host immune responses. Importantly, immunization with cryptococcal cells overexpressing ZNF2, either in live or heat-inactivated form, offers significant protection to the host from a subsequent challenge by the otherwise lethal wild-type H99 strain. We hypothesize that cellular components enriched in ZNF2oe cells are immunoprotective. Here, we discovered that serum from protected animals vaccinated with inactivated ZNF2oe cells recognizes cryptococcal antigens that reside within the capsule. Consistently, capsule is required for immunoprotection offered by ZNF2oe cells. Interestingly, the serum from protective animals recognizes antigens in both wild-type yeast cells and ZNF2oe cells, with higher abundance in the latter. Consequently, even the heat-inactivated wild-type cells become immunoprotective with an increased vaccination dose. We also found that disruption of a chromatin remodeling factor Brf1, which is important for initiation of filamentation by Znf2, reduces the antigen level in ZNF2oe cells. Deletion of BRF1 drastically reduces the protective effect of ZNF2oe cells in both live and heat-killed forms even though the ZNF2oebrf1Δ strain itself is avirulent. Collectively, our findings underscore the importance of identifying the subset of cryptococcal surface factors that are beneficial in host protection. IMPORTANCE Cryptococcosis claims close to 200,000 lives annually. There is no vaccine clinically available for this fungal disease. Many avirulent mutant strains do not provide protection against cryptococcosis. We previously discovered that hyphal ZNF2oe strains elicit protective host immune responses both in the live and heat-inactivated forms. Here we seek to understand the mechanism underlying the host protection provided by ZNF2oe cells. We discovered increased accumulation of antigens located within the caspusle of ZNF2oe cells and consequently the requirement of the capsule for ZNF2oe strain-elicited host protection. Furthermore, genetically blocking the ability of ZNF2oe cells to grow in the hyphal form significantly reduces antigen accumulation and impairs the ability of ZNF2oe strain to provide host protection. Our findings highlight the importance of identifying the Znf2-regulated capsular surface factors that are fundamental in host protection.
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20
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Identification and Characterization of an Intergenic “Safe Haven” Region in Human Fungal Pathogen Cryptococcus gattii. J Fungi (Basel) 2022; 8:jof8020178. [PMID: 35205930 PMCID: PMC8874978 DOI: 10.3390/jof8020178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Revised: 02/09/2022] [Accepted: 02/09/2022] [Indexed: 12/10/2022] Open
Abstract
Cryptococcus gattii is a primary fungal pathogen, which causes pulmonary and brain infections in healthy as well as immunocompromised individuals. Genetic manipulations in this pathogen are widely employed to study its biology and pathogenesis, and require integration of foreign DNA into the genome. Thus, identification of gene free regions where integrated foreign DNA can be expressed without influencing, or being influenced by, nearby genes would be extremely valuable. To achieve this goal, we examined publicly available genomes and transcriptomes of C. gattii, and identified two intergenic regions in the reference strain R265 as potential “safe haven” regions, named as CgSH1 and CgSH2. We found that insertion of a fluorescent reporter gene and a selection marker at these two intergenic regions did not affect the expression of their neighboring genes and were also expressed efficiently, as expected. Furthermore, DNA integration at CgSH1 or CgSH2 had no apparent effect on the growth of C. gattii, its response to various stresses, or phagocytosis by macrophages. Thus, the identified safe haven regions in C. gattii provide an effective tool for researchers to reduce variation and increase reproducibility in genetic experiments.
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Li R, Zhu L, Liu D, Wang W, Zhang C, Jiao S, Wei J, Ren L, Zhang Y, Gou X, Yuan X, Du Y, Wang ZA. High molecular weight chitosan oligosaccharide exhibited antifungal activity by misleading cell wall organization via targeting PHR transglucosidases. Carbohydr Polym 2022; 285:119253. [DOI: 10.1016/j.carbpol.2022.119253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 01/12/2022] [Accepted: 02/11/2022] [Indexed: 11/02/2022]
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22
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Kelly M, Pasmans F, Muñoz JF, Shea TP, Carranza S, Cuomo CA, Martel A. Diversity, multifaceted evolution, and facultative saprotrophism in the European Batrachochytrium salamandrivorans epidemic. Nat Commun 2021; 12:6688. [PMID: 34795258 PMCID: PMC8602665 DOI: 10.1038/s41467-021-27005-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 10/28/2021] [Indexed: 01/06/2023] Open
Abstract
While emerging fungi threaten global biodiversity, the paucity of fungal genome assemblies impedes thoroughly characterizing epidemics and developing effective mitigation strategies. Here, we generate de novo genomic assemblies for six outbreaks of the emerging pathogen Batrachochytrium salamandrivorans (Bsal). We reveal the European epidemic currently damaging amphibian populations to comprise multiple, highly divergent lineages demonstrating isolate-specific adaptations and metabolic capacities. In particular, we show extensive gene family expansions and acquisitions, through a variety of evolutionary mechanisms, and an isolate-specific saprotrophic lifecycle. This finding both explains the chytrid's ability to divorce transmission from host density, producing Bsal's enigmatic host population declines, and is a key consideration in developing successful mitigation measures.
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Affiliation(s)
- Moira Kelly
- Wildlife Health Ghent, Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, 9820, Merelbeke, Belgium.
| | - Frank Pasmans
- grid.5342.00000 0001 2069 7798Wildlife Health Ghent, Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium
| | - Jose F. Muñoz
- grid.66859.34Broad Institute of MIT and Harvard, Cambridge, 02142 MA USA
| | - Terrance P. Shea
- grid.66859.34Broad Institute of MIT and Harvard, Cambridge, 02142 MA USA
| | - Salvador Carranza
- grid.507636.10000 0004 0424 5398Institute of Evolutionary Biology (CSIC-UPF), 08003 Barcelona, Spain
| | - Christina A. Cuomo
- grid.66859.34Broad Institute of MIT and Harvard, Cambridge, 02142 MA USA
| | - An Martel
- Wildlife Health Ghent, Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, 9820, Merelbeke, Belgium.
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23
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Upadhya R, Lam WC, Hole CR, Parchment D, Lee CK, Specht CA, Levitz SM, Lodge JK. Cryptococcus neoformans Cda1 and Cda2 coordinate deacetylation of chitin during infection to control fungal virulence. ACTA ACUST UNITED AC 2021; 7:100066. [PMID: 34712865 PMCID: PMC8529172 DOI: 10.1016/j.tcsw.2021.100066] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 10/11/2021] [Accepted: 10/11/2021] [Indexed: 11/25/2022]
Abstract
Chitosan, a deacetylated form of chitin, is required for the virulence of Cryptococcus neoformans. There are three chitin deacetylase genes (CDA) that are essential for chitosan production, and deletion of all three genes results in the absence of chitosan, loss of virulence, and induction of a protective host response when used as a vaccine. Cda1 plays a major role in deacetylating chitin during pulmonary infection of CBA/J mice. Inoculation with the cda1Δ strain did not lead to a lethal infection. However, the infection was not cleared. The persistence of the fungus in the host suggests that chitin is still being deacetylated by Cda2 and/or Cda3. To test this hypothesis, we subjected strains deleted of two CDA genes to fungal virulence in CBA/J, C57BL/6 and BALB/c and found that cda1Δcda2Δ was avirulent in all mouse lines, as evidenced by its complete clearance. Consistent with the major role of Cda1 in CBA/J, we found that cda2Δcda3Δ was as virulent as its wild-type progenitor KN99. On the other hand, cda1Δcda3Δ displayed virulence comparable to that of cda1Δ. The virulence of each mutant correlates with the amount of chitosan produced when grown under host-mimicking culture conditions. In addition, the avirulence of cda1Δcda2Δ was followed by the induction of a protective immune response in C57BL/6 and CBA/J mice, when a live or heat-killed form of the mutant was used as a vaccine respectively. Taken together, these data imply that, in C. neoformans, coordinated activity of both Cda1 and Cda2 is essential for mediating fungal virulence.
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Affiliation(s)
- Rajendra Upadhya
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Woei C Lam
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Camaron R Hole
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Danealle Parchment
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Chrono K Lee
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | - Charles A Specht
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | - Stuart M Levitz
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | - Jennifer K Lodge
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA
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Adenylyl Cyclase and Protein Kinase A Play Redundant and Distinct Roles in Growth, Differentiation, Antifungal Drug Resistance, and Pathogenicity of Candida auris. mBio 2021; 12:e0272921. [PMID: 34663094 PMCID: PMC8524339 DOI: 10.1128/mbio.02729-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Candida auris is a globally emerging multidrug-resistant fungal pathogen. Its pathogenicity-related signaling networks are largely unknown. Here, we characterized the pathobiological functions of the cyclic AMP (cAMP)/protein kinase A (PKA) signaling pathway in C. auris. We focused on adenylyl cyclase (CYR1), the PKA regulatory subunit (BCY1), and the PKA catalytic subunits (TPK1 and TPK2). We concluded that PKA acts both dependently and independently of Cyr1 in C. auris. Tpk1 and Tpk2 have major and minor roles, respectively, in PKA activity and functions. Both Cyr1 and PKA promote growth, thermotolerance, filamentous growth, and resistance to stress and antifungal drugs by regulating expression of multiple effector genes. In addition, Cyr1 and PKA subunits were involved in disinfectant resistance of C. auris. However, deletion of both TPK1 and TPK2 generally resulted in more severe defects than CYR1 deletion, indicating that Cyr1 and PKA play redundant and distinct roles. Notably, Tpk1 and Tpk2 have redundant but Cyr1-independent roles in haploid-to-diploid cell transition, which increases virulence of C. auris. However, Tpk1 and Tpk2 often play opposing roles in formation of biofilms and the cell wall components chitin and chitosan. Surprisingly, deletion of CYR1 or TPK1/TPK2, which resulted in severe in vitro growth defects at 37°C, did not attenuate virulence, and BCY1 deletion reduced virulence of C. auris in a systemic murine infection model. In conclusion, this study provides comprehensive insights into the role of the cAMP/PKA pathway in drug resistance and pathogenicity of C. auris and suggests a potential therapeutic option for treatment of C. auris-mediated candidemia.
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Abstract
Fungi are eukaryotic microorganisms that show complex life cycles, including both anamorph and teleomorph stages. Beta-1,3-1,6-glucans (BGs) are major cell wall components in fungi. BGs are also found in a soluble form and are secreted by fungal cells. Studies of fungal BGs extensively expanded from 1960 to 1990 due to their applications in cancer immunotherapy. However, progress in this field slowed down due to the low efficacy of such therapies. In the early 21st century, the discovery of C-type lectin receptors significantly enhanced the molecular understanding of innate immunity. Moreover, pathogen-associated molecular patterns (PAMPs) and pattern recognition receptors (PRRs) were also discovered. Soon, dectin-1 was identified as the PRR of BGs, whereas BGs were established as PAMPs. Then, studies on fungal BGs focused on their participation in the development of deep-seated mycoses and on their role as a source of functional foods. Fungal BGs may have numerous and complex linkages, making it difficult to systematize them even at the primary structure level. Moreover, elucidating the structure of BGs is largely hindered by the multiplicity of genes involved in cell wall biosynthesis, including those for BGs, and by fungal diversity. The present review mainly focused on the characteristics of fungal BGs from the viewpoint of structure and immunological activities.
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26
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Specht CA, Homan EJ, Lee CK, Mou Z, Gomez CL, Hester MM, Abraham A, Rus F, Ostroff GR, Levitz SM. Protection of Mice against Experimental Cryptococcosis by Synthesized Peptides Delivered in Glucan Particles. mBio 2021; 13:e0336721. [PMID: 35089095 PMCID: PMC8725579 DOI: 10.1128/mbio.03367-21] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 11/23/2021] [Indexed: 12/22/2022] Open
Abstract
The high global burden of cryptococcosis has made development of a protective vaccine a public health priority. We previously demonstrated that a vaccine composed of recombinant Cryptococcus neoformans chitin deacetylase 2 (Cda2) delivered in glucan particles (GPs) protects BALB/c and C57BL/6 mice from an otherwise lethal challenge with a highly virulent C. neoformans strain. An immunoinformatic analysis of Cda2 revealed a peptide sequence predicted to have strong binding to the major histocompatibility complex class II (MHC II) H2-IAd allele found in BALB/c mice. BALB/c mice vaccinated with GPs containing a 32-amino-acid peptide (Cda2-Pep1) that included this strong binding region were protected from cryptococcosis. Protection was lost with GP-based vaccines containing versions of recombinant Cda2 protein and Cda2-Pep1 with mutations predicted to greatly diminish MHC II binding. Cda2 has homology to the three other C. neoformans chitin deacetylases, Cda1, Cda3, and Fpd1, in the high-MHC II-binding region. GPs loaded with homologous peptides of Cda1, Cda3, and Fpd1 protected BALB/c mice from experimental cryptococcosis, albeit not as robustly as the Cda2-Pep1 vaccine. Finally, seven other peptides were synthesized based on regions in Cda2 predicted to contain promising CD4+ T cell epitopes in BALB/c or C57BL/6 mice. While five peptide vaccines significantly protected BALB/c mice, only one protected C57BL/6 mice. Thus, GP-based vaccines containing a single peptide can protect mice against cryptococcosis. However, given the diversity of human MHC II alleles, a peptide-based Cryptococcus vaccine for use in humans would be challenging and likely need to contain multiple peptide sequences. IMPORTANCE Cryptococcosis, due to infection by fungi of the Cryptococcus neoformans species complex, is responsible for substantial morbidity and mortality in immunocompromised persons, particularly those with AIDS. Cryptococcal vaccines are a public health priority yet are not available for human use. We previously demonstrated mice could be protected from experimental cryptococcosis with vaccines composed of recombinant cryptococcal proteins encased in hollow highly purified yeast cell walls (glucan particles). In this study, we examined one such protective protein, Cda2, and using bioinformatics, we identified a region predicted to stimulate strong T cell responses. A peptide containing this region formulated in glucan particle-based vaccines protected mice as well as the recombinant protein. Other peptide vaccines also protected, including peptides containing sequences from proteins homologous to Cda2. These preclinical mouse studies provide a proof of principle that peptides can be effective as vaccines to protect against cryptococcosis and that bioinformatic approaches can guide peptide selection.
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Affiliation(s)
- Charles A. Specht
- Department of Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | | | - Chrono K. Lee
- Department of Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Zhongming Mou
- Department of Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Christina L. Gomez
- Department of Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Maureen M. Hester
- Department of Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Ambily Abraham
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Florentina Rus
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Gary R. Ostroff
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Stuart M. Levitz
- Department of Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
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27
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Choquer M, Rascle C, Gonçalves IR, de Vallée A, Ribot C, Loisel E, Smilevski P, Ferria J, Savadogo M, Souibgui E, Gagey MJ, Dupuy JW, Rollins JA, Marcato R, Noûs C, Bruel C, Poussereau N. The infection cushion of Botrytis cinerea: a fungal 'weapon' of plant-biomass destruction. Environ Microbiol 2021; 23:2293-2314. [PMID: 33538395 DOI: 10.1111/1462-2920.15416] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 01/28/2021] [Indexed: 02/07/2023]
Abstract
The necrotrophic plant-pathogen fungus Botrytis cinerea produces multicellular appressoria dedicated to plant penetration, named infection cushions (IC). A microarray analysis was performed to identify genes upregulated in mature IC. The expression data were validated by RT-qPCR analysis performed in vitro and in planta, proteomic analysis of the IC secretome and biochemical assays. 1231 upregulated genes and 79 up-accumulated proteins were identified. The data support the secretion of effectors by IC: phytotoxins, ROS, proteases, cutinases, plant cell wall-degrading enzymes and plant cell death-inducing proteins. Parallel upregulation of sugar transport and sugar catabolism-encoding genes would indicate a role of IC in nutrition. The data also reveal a substantial remodelling of the IC cell wall and suggest a role for melanin and chitosan in IC function. Lastly, mutagenesis of two upregulated genes in IC identified secreted fasciclin-like proteins as actors in the pathogenesis of B. cinerea. These results support the role of IC in plant penetration and also introduce other unexpected functions for this fungal organ, in colonization, necrotrophy and nutrition of the pathogen.
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Affiliation(s)
- Mathias Choquer
- Univ Lyon, Université Lyon 1, CNRS, INSA-Lyon, Microbiologie, Adaptation et Pathogénie, UMR 5240 MAP, 10 Rue Raphaël Dubois, Villeurbanne, F-69622, France.,Bayer SAS, Crop Science Division, Laboratoire Mixte, 14 Impasse Pierre Baizet, Lyon, F-69263, France
| | - Christine Rascle
- Univ Lyon, Université Lyon 1, CNRS, INSA-Lyon, Microbiologie, Adaptation et Pathogénie, UMR 5240 MAP, 10 Rue Raphaël Dubois, Villeurbanne, F-69622, France.,Bayer SAS, Crop Science Division, Laboratoire Mixte, 14 Impasse Pierre Baizet, Lyon, F-69263, France
| | - Isabelle R Gonçalves
- Univ Lyon, Université Lyon 1, CNRS, INSA-Lyon, Microbiologie, Adaptation et Pathogénie, UMR 5240 MAP, 10 Rue Raphaël Dubois, Villeurbanne, F-69622, France.,Bayer SAS, Crop Science Division, Laboratoire Mixte, 14 Impasse Pierre Baizet, Lyon, F-69263, France
| | - Amélie de Vallée
- Univ Lyon, Université Lyon 1, CNRS, INSA-Lyon, Microbiologie, Adaptation et Pathogénie, UMR 5240 MAP, 10 Rue Raphaël Dubois, Villeurbanne, F-69622, France.,Bayer SAS, Crop Science Division, Laboratoire Mixte, 14 Impasse Pierre Baizet, Lyon, F-69263, France
| | - Cécile Ribot
- Univ Lyon, Université Lyon 1, CNRS, INSA-Lyon, Microbiologie, Adaptation et Pathogénie, UMR 5240 MAP, 10 Rue Raphaël Dubois, Villeurbanne, F-69622, France
| | - Elise Loisel
- Univ Lyon, Université Lyon 1, CNRS, INSA-Lyon, Microbiologie, Adaptation et Pathogénie, UMR 5240 MAP, 10 Rue Raphaël Dubois, Villeurbanne, F-69622, France.,Bayer SAS, Crop Science Division, Laboratoire Mixte, 14 Impasse Pierre Baizet, Lyon, F-69263, France
| | - Pavlé Smilevski
- Univ Lyon, Université Lyon 1, CNRS, INSA-Lyon, Microbiologie, Adaptation et Pathogénie, UMR 5240 MAP, 10 Rue Raphaël Dubois, Villeurbanne, F-69622, France.,Bayer SAS, Crop Science Division, Laboratoire Mixte, 14 Impasse Pierre Baizet, Lyon, F-69263, France
| | - Jordan Ferria
- Univ Lyon, Université Lyon 1, CNRS, INSA-Lyon, Microbiologie, Adaptation et Pathogénie, UMR 5240 MAP, 10 Rue Raphaël Dubois, Villeurbanne, F-69622, France.,Bayer SAS, Crop Science Division, Laboratoire Mixte, 14 Impasse Pierre Baizet, Lyon, F-69263, France
| | - Mahamadi Savadogo
- Univ Lyon, Université Lyon 1, CNRS, INSA-Lyon, Microbiologie, Adaptation et Pathogénie, UMR 5240 MAP, 10 Rue Raphaël Dubois, Villeurbanne, F-69622, France.,Bayer SAS, Crop Science Division, Laboratoire Mixte, 14 Impasse Pierre Baizet, Lyon, F-69263, France
| | - Eytham Souibgui
- Univ Lyon, Université Lyon 1, CNRS, INSA-Lyon, Microbiologie, Adaptation et Pathogénie, UMR 5240 MAP, 10 Rue Raphaël Dubois, Villeurbanne, F-69622, France.,Bayer SAS, Crop Science Division, Laboratoire Mixte, 14 Impasse Pierre Baizet, Lyon, F-69263, France
| | - Marie-Josèphe Gagey
- Univ Lyon, Université Lyon 1, CNRS, INSA-Lyon, Microbiologie, Adaptation et Pathogénie, UMR 5240 MAP, 10 Rue Raphaël Dubois, Villeurbanne, F-69622, France.,Bayer SAS, Crop Science Division, Laboratoire Mixte, 14 Impasse Pierre Baizet, Lyon, F-69263, France
| | - Jean-William Dupuy
- Plateforme Protéome, Centre de Génomique Fonctionnelle, Université de Bordeaux, Bordeaux, France
| | - Jeffrey A Rollins
- Department of Plant Pathology, University of Florida, Gainesville, FL, USA
| | - Riccardo Marcato
- Bayer SAS, Crop Science Division, Laboratoire Mixte, 14 Impasse Pierre Baizet, Lyon, F-69263, France.,Department of Land, Environment, Agriculture and Forestry (TESAF), Research Group in Plant Pathology, Università degli Studi di Padova, Legnaro, Italy
| | - Camille Noûs
- Univ Lyon, Université Lyon 1, CNRS, INSA-Lyon, Microbiologie, Adaptation et Pathogénie, UMR 5240 MAP, 10 Rue Raphaël Dubois, Villeurbanne, F-69622, France
| | - Christophe Bruel
- Univ Lyon, Université Lyon 1, CNRS, INSA-Lyon, Microbiologie, Adaptation et Pathogénie, UMR 5240 MAP, 10 Rue Raphaël Dubois, Villeurbanne, F-69622, France.,Bayer SAS, Crop Science Division, Laboratoire Mixte, 14 Impasse Pierre Baizet, Lyon, F-69263, France
| | - Nathalie Poussereau
- Univ Lyon, Université Lyon 1, CNRS, INSA-Lyon, Microbiologie, Adaptation et Pathogénie, UMR 5240 MAP, 10 Rue Raphaël Dubois, Villeurbanne, F-69622, France.,Bayer SAS, Crop Science Division, Laboratoire Mixte, 14 Impasse Pierre Baizet, Lyon, F-69263, France
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28
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Replicative Aging Remodels the Cell Wall and Is Associated with Increased Intracellular Trafficking in Human Pathogenic Yeasts. mBio 2021; 13:e0019022. [PMID: 35164553 PMCID: PMC8844920 DOI: 10.1128/mbio.00190-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Replicative aging is an underexplored field of research in medical mycology. Cryptococcus neoformans (Cn) and Candida glabrata (Cg) are dreaded fungal pathogens that cause fatal invasive infections. The fungal cell wall is essential for yeast viability and pathogenesis. In this study, we provide data characterizing age-associated modifications to the cell wall of Cn and Cg. Here, we report that old yeast cells upregulate genes of cell wall biosynthesis, leading to cell wall reorganization and increased levels of all major components, including glucan, chitin, and its derivatives, as well as mannan. This results in a significant thickening of the cell wall in aged cells. Old-generation yeast cells exhibited drastic ultrastructural changes, including the presence of abundant vesicle-like particles in the cytoplasm, and enlarged vacuoles with altered pH homeostasis. Our findings suggest that the cell wall modifications could be enabled by augmented intracellular trafficking. This work furthers our understanding of the cell phenotype that emerges during aging. It highlights differences in these two fungal pathogens and elucidates mechanisms that explain the enhanced resistance of old cells to antifungals and phagocytic attacks. IMPORTANCE Cryptococcus neoformans and Candida glabrata are two opportunistic human fungal pathogens that cause life-threatening diseases. During infection, both microorganisms have the ability to persist for long periods, and treatment failure can occur even if standard testing identifies the yeasts to be sensitive to antifungals. Replicative life span is a trait that is measured by the number of divisions a cell undergoes before death. Aging in fungi is associated with enhanced tolerance to antifungals and resistance to phagocytosis, and characterization of old cells may help identify novel antifungal targets. The cell wall remains an attractive target for new therapies because it is essential for fungi and is not present in humans. This study shows that the organization of the fungal cell wall changes remarkably during aging and becomes thicker and is associated with increased intracellular trafficking as well as the alteration of vacuole morphology and pH homeostasis.
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29
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Evolutionary and genomic comparisons of hybrid uninucleate and nonhybrid Rhizoctonia fungi. Commun Biol 2021; 4:201. [PMID: 33589695 PMCID: PMC7884421 DOI: 10.1038/s42003-021-01724-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 01/19/2021] [Indexed: 01/30/2023] Open
Abstract
The basidiomycetous fungal genus, Rhizoctonia, can cause severe damage to many plants and is composed of multinucleate, binucleate, and uninucleate species differing in pathogenicity. Here we generated chromosome-scale genome assemblies of the three nuclear types of Rhizoctonia isolates. The genomic comparisons revealed that the uninucleate JN strain likely arose by somatic hybridization of two binucleate isolates, and maintained a diploid nucleus. Homeolog gene pairs in the JN genome have experienced both decelerated or accelerated evolution. Homeolog expression dominance occurred between JN subgenomes, in which differentially expressed genes show potentially less evolutionary constraint than the genes without. Analysis of mating-type genes suggested that Rhizoctonia maintains the ancestral tetrapolarity of the Basidiomycota. Long terminal repeat-retrotransposons displayed a reciprocal correlation with the chromosomal GC content in the three chromosome-scale genomes. The more aggressive multinucleate XN strain had more genes encoding enzymes for host cell wall decomposition. These findings demonstrate some evolutionary changes of a recently derived hybrid and in multiple nuclear types of Rhizoctonia.
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30
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Plaza V, Silva-Moreno E, Castillo L. Breakpoint: Cell Wall and Glycoproteins and their Crucial Role in the Phytopathogenic Fungi Infection. Curr Protein Pept Sci 2021; 21:227-244. [PMID: 31490745 DOI: 10.2174/1389203720666190906165111] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 08/02/2019] [Accepted: 08/17/2019] [Indexed: 01/09/2023]
Abstract
The cell wall that surrounds fungal cells is essential for their survival, provides protection against physical and chemical stresses, and plays relevant roles during infection. In general, the fungal cell wall is composed of an outer layer of glycoprotein and an inner skeletal layer of β-glucans or α- glucans and chitin. Chitin synthase genes have been shown to be important for septum formation, cell division and virulence. In the same way, chitin can act as a potent elicitor to activate defense response in several plant species; however, the fungi can convert chitin to chitosan during plant infection to evade plant defense mechanisms. Moreover, α-1,3-Glucan, a non-degradable polysaccharide in plants, represents a key feature in fungal cell walls formed in plants and plays a protective role for this fungus against plant lytic enzymes. A similar case is with β-1,3- and β-1,6-glucan which are essential for infection, structure rigidity and pathogenicity during fungal infection. Cell wall glycoproteins are also vital to fungi. They have been associated with conidial separation, the increase of chitin in conidial cell walls, germination, appressorium formation, as well as osmotic and cell wall stress and virulence; however, the specific roles of glycoproteins in filamentous fungi remain unknown. Fungi that can respond to environmental stimuli distinguish these signals and relay them through intracellular signaling pathways to change the cell wall composition. They play a crucial role in appressorium formation and penetration, and release cell wall degrading enzymes, which determine the outcome of the interaction with the host. In this review, we highlight the interaction of phypatophogen cell wall and signaling pathways with its host and their contribution to fungal pathogenesis.
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Affiliation(s)
- Verónica Plaza
- Laboratorio de Biología Molecular y Bioquímica, Departamento de Biología, Universidad de La Serena, La Serena, Chile
| | - Evelyn Silva-Moreno
- Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Temuco, Chile
| | - Luis Castillo
- Laboratorio de Biología Molecular y Bioquímica, Departamento de Biología, Universidad de La Serena, La Serena, Chile
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31
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Treatment strategies for cryptococcal infection: challenges, advances and future outlook. Nat Rev Microbiol 2021; 19:454-466. [PMID: 33558691 PMCID: PMC7868659 DOI: 10.1038/s41579-021-00511-0] [Citation(s) in RCA: 135] [Impact Index Per Article: 45.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/07/2021] [Indexed: 01/31/2023]
Abstract
Cryptococcus spp., in particular Cryptococcus neoformans and Cryptococcus gattii, have an enormous impact on human health worldwide. The global burden of cryptococcal meningitis is almost a quarter of a million cases and 181,000 deaths annually, with mortality rates of 100% if infections remain untreated. Despite these alarming statistics, treatment options for cryptococcosis remain limited, with only three major classes of drugs approved for clinical use. Exacerbating the public health burden is the fact that the only new class of antifungal drugs developed in decades, the echinocandins, displays negligible antifungal activity against Cryptococcus spp., and the efficacy of the remaining therapeutics is hampered by host toxicity and pathogen resistance. Here, we describe the current arsenal of antifungal agents and the treatment strategies employed to manage cryptococcal disease. We further elaborate on the recent advances in our understanding of the intrinsic and adaptive resistance mechanisms that are utilized by Cryptococcus spp. to evade therapeutic treatments. Finally, we review potential therapeutic strategies, including combination therapy, the targeting of virulence traits, impairing stress response pathways and modulating host immunity, to effectively treat infections caused by Cryptococcus spp. Overall, understanding of the mechanisms that regulate anti-cryptococcal drug resistance, coupled with advances in genomics technologies and high-throughput screening methodologies, will catalyse innovation and accelerate antifungal drug discovery.
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32
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Tsvetkov YE, Paulovičová E, Paulovičová L, Farkaš P, Nifantiev NE. Synthesis of Biotin-Tagged Chitosan Oligosaccharides and Assessment of Their Immunomodulatory Activity. Front Chem 2020; 8:554732. [PMID: 33335882 PMCID: PMC7736555 DOI: 10.3389/fchem.2020.554732] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 10/20/2020] [Indexed: 01/10/2023] Open
Abstract
Chitin, a polymer of β-(1→4)-linked N-acetyl-d-glucosamine, is one of the main polysaccharide components of the fungal cell wall. Its N-deacetylated form, chitosan, is enzymatically produced in the cell wall by chitin deacetylases. It exerts immunomodulative, anti-inflammatory, anti-cancer, anti-bacterial, and anti-fungal activities with various medical applications. To study the immunobiological properties of chitosan oligosaccharides, we synthesized a series of β-(1→4)-linked N-acetyl-d-glucosamine oligomers comprising 3, 5, and 7 monosaccharide units equipped with biotin tags. The key synthetic intermediate employed for oligosaccharide chain elongation, a disaccharide thioglycoside, was prepared by orthogonal glycosylation of a 4-OH thioglycoside acceptor with a glycosyl trichloroacetimidate bearing the temporary 4-O-tert-butyldimethylsilyl group. The use of silyl protection suppressed aglycon transfer and provided a high yield for the target disaccharide donor. Using synthesized chitosan oligomers, as well as previously obtained chitin counterparts, the immunobiological relationship between these synthetic oligosaccharides and RAW 264.7 cells was studied in vitro. Evaluation of cell proliferation, phagocytosis, respiratory burst, and Th1, Th2, Th17, and Treg polarized cytokine expression demonstrated effective immune responsiveness and immunomodulation in RAW 264.7 cells exposed to chitin- and chitosan-derived oligosaccharides. Macrophage reactivity was accompanied by significant inductive dose- and structure-dependent protective Th1 and Th17 polarization, which was greater with exposure to chitosan- rather than chitin-derived oligosaccharides. Moreover, no antiproliferative or cytotoxic effects were observed, even following prolonged 48 h exposure. The obtained results demonstrate the potent immunobiological activity of these synthetically prepared chito-oligosaccharides.
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Affiliation(s)
- Yury E. Tsvetkov
- Laboratory of Glycoconjugate Chemistry, N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Ema Paulovičová
- Cell Culture & Immunology Laboratory, Department of Immunochemistry of Glycoconjugates, Center for Glycomics, Institute of Chemistry, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Lucia Paulovičová
- Cell Culture & Immunology Laboratory, Department of Immunochemistry of Glycoconjugates, Center for Glycomics, Institute of Chemistry, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Pavol Farkaš
- Cell Culture & Immunology Laboratory, Department of Immunochemistry of Glycoconjugates, Center for Glycomics, Institute of Chemistry, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Nikolay E. Nifantiev
- Laboratory of Glycoconjugate Chemistry, N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia
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33
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Evolutionary analysis and protein family classification of chitin deacetylases in Cryptococcus neoformans. J Microbiol 2020; 58:805-811. [PMID: 32870486 DOI: 10.1007/s12275-020-0288-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 07/15/2020] [Accepted: 07/23/2020] [Indexed: 10/23/2022]
Abstract
Cryptococcus neoformans is an opportunistic fungal pathogen causing cryptococcal meningoencephalitis. Interestingly, the cell wall of C. neoformans contains chitosan, which is critical for its virulence and persistence in the mammalian host. C. neoformans (H99) has three chitin deacetylases (CDAs), which convert chitin to chitosan. Herein, the classification of the chitin-related protein (CRP) family focused on cryptococcal CDAs was analyzed by phylogenetics, evolutionary pressure (dN/dS), and 3D modeling. A phylogenetic tree of 110 CRPs revealed that they can be divided into two clades, CRP I and II with bootstrap values (> 99%). CRP I clade comprises five groups (Groups 1-5) with a total of 20 genes, while CRP II clade comprises sixteen groups (Groups 6-21) with a total of 90 genes. CRP I comprises only fungal CDAs, including all three C. neoformans CDAs, whereas CRP II comprises diverse CDAs from fungi, bacteria, and amoeba, along with other carbohydrate esterase 4 family proteins. All CDAs have the signal peptide, except those from group 11. Notably, CDAs with the putative O-gycosylation site possess either the glycosylphosphatidylinositol (GPI)-anchor motif for CRP I or the chitin-binding domain (CBD) for CRP II, respectively. This evolutionary conservation strongly indicates that the O-glycosylation modification and the presence of either the GPI-anchor motif or the chitin-binding domain is important for fungal CDAs to function efficiently at the cell surface. This study reveals that C. neoformans CDAs carrying GPI anchors have evolved divergently from fungal and bacterial CDAs, providing new insights into evolution and classification of CRP family.
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Unveiling the Properties of Thai Stingless Bee Propolis via Diminishing Cell Wall-Associated Cryptococcal Melanin and Enhancing the Fungicidal Activity of Macrophages. Antibiotics (Basel) 2020; 9:antibiotics9070420. [PMID: 32709077 PMCID: PMC7400477 DOI: 10.3390/antibiotics9070420] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 07/05/2020] [Accepted: 07/15/2020] [Indexed: 11/16/2022] Open
Abstract
Cryptococcus neoformans, a life-threatening human yeast pathogen, has the ability to produce melanin, which is one of the common virulence factors contributing to cryptococcal pathogenesis. This virulence factor is closely associated with the cryptococcal cell wall, specifically chitin and chitosan polysaccharides, a complex structure that is essential for maintaining cellular structure and integrity. In this study, we aim to investigate the effects of two stingless bee (SLB) propolis from Tetragonula laeviceps and Tetrigona melanoleuca against cell wall-associated melanin in C. neoformans, and its immune response in RAW 264.7 macrophage. The ethanolic extract of SLB propolis (EEP) has strongly exhibited anti-cryptococcal activity. Moreover, EEP from both sources reduced chitin/chitosan and melanin production against C. neoformans in a dose-dependent manner. Likewise, the mRNA expression level of CDA1, IPC1-PKC1 and LAC1 genes involved in the cryptococcal melanization pathway was significantly decreased at 2 mg/mL in EEP treatment. Additionally, pretreatment with EEP prior to yeast infection dramatically reduced intracellular replication of C. neoformans in RAW 264.7 macrophages in a dose-dependent manner. This study might be a new insight to use a natural powerful source, not only acting to target cell wall-associated molecules, but also being capable to explore a novel strategy by which dysregulation of these molecules leads to promote immunomodulatory activity.
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Yi J, Sang J, Zhao J, Gao L, Yang Y, Yan L, Zhang C, Pan W, Wang G, Liao W. Transcription factor Liv4 is required for growth and pathogenesis of Cryptococcus neoformans. FEMS Yeast Res 2020; 20:foaa015. [PMID: 32391887 DOI: 10.1093/femsyr/foaa015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 04/03/2020] [Indexed: 11/13/2022] Open
Abstract
Cryptococcus neoformans is an important invasive fungal pathogen that causes life-threatening meningoencephalitis in humans. Its biological and pathogenic regulatory mechanisms remain largely unknown, particularly due to the presence of those core transcription factors (TFs). Here, we conducted a detailed characterization of the TF Liv4 in the biology and virulence of C. neoformans. Deletion of TF Liv4 protein resulted in growth defect under both normal and stress conditions (such as high temperature and cell wall/membrane damaging agents), drastic morphological damage and also attenuated virulence in C. neoformans. These phenotypic changes might be contributed to transcriptional abnormality in the liv4Δ mutant, in which several cryptococcal genes involved in energy metabolism and cell wall integrity were downregulated. Furthermore, ChIP-seq and ChIP-qPCR assays suggested TF Liv4 might exert its regulatory function in transcription by its activation of RBP1 in C. neoformans. Taken together, our work highlights the importance of TF Liv4 in the growth and virulence of C. neoformans, and it facilitates a better understanding of cryptococcal pathogenesis mechanisms.
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Affiliation(s)
- Jiu Yi
- Department of Dermatology, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, 200003, China
- Shanghai Key Laboratory of Molecular Medical Mycology, Shanghai Institute of Medical Mycology, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, 200003, China
| | - Junjun Sang
- Shanghai Key Laboratory of Molecular Medical Mycology, Shanghai Institute of Medical Mycology, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, 200003, China
- Department of Dermatology, 900 Hospital of the Joint Logistics Team, Fuzhou, Fujian Province, 350025, China
| | - Jingyu Zhao
- Shanghai Key Laboratory of Molecular Medical Mycology, Shanghai Institute of Medical Mycology, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, 200003, China
- Department of Dermatology, Shanghai Eastern Hepatobiliary Surgery Hospital, Shanghai, 201805, China
| | - Lei Gao
- Shanghai Key Laboratory of Molecular Medical Mycology, Shanghai Institute of Medical Mycology, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, 200003, China
| | - Yali Yang
- Shanghai Key Laboratory of Molecular Medical Mycology, Shanghai Institute of Medical Mycology, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, 200003, China
| | - Lei Yan
- Shanghai Key Laboratory of Molecular Medical Mycology, Shanghai Institute of Medical Mycology, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, 200003, China
| | - Chao Zhang
- Department of Dermatology, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, 200003, China
- Shanghai Key Laboratory of Molecular Medical Mycology, Shanghai Institute of Medical Mycology, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, 200003, China
| | - Weihua Pan
- Department of Dermatology, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, 200003, China
- Shanghai Key Laboratory of Molecular Medical Mycology, Shanghai Institute of Medical Mycology, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, 200003, China
| | - Guizhen Wang
- Emergency room, Shanghai Tenth People's Hospital of Tongji University, 200072, Shanghai, China
| | - Wanqing Liao
- Department of Dermatology, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, 200003, China
- Shanghai Key Laboratory of Molecular Medical Mycology, Shanghai Institute of Medical Mycology, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, 200003, China
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Variation in Cell Surface Hydrophobicity among Cryptococcus neoformans Strains Influences Interactions with Amoebas. mSphere 2020; 5:5/2/e00310-20. [PMID: 32350094 PMCID: PMC7193044 DOI: 10.1128/msphere.00310-20] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Cryptococcus neoformans and Cryptococcus gattii are pathogenic fungi that cause significant morbidity and mortality. Cell surface hydrophobicity (CSH) is a biophysical parameter that influences the adhesion of fungal cells or spores to biotic and abiotic surfaces. C. neoformans is encased by polysaccharide capsule that is highly hydrophilic and is a critical determinant of virulence. In this study, we report large differences in the CSH of some C. neoformans and C. gattii strains. The capsular polysaccharides of C. neoformans strains differ in repeating motifs and therefore vary in the number of hydroxyl groups, which, along with higher-order structure of the capsule, may contribute to the variation in hydrophobicity that we observed. We found that cell wall composition, in the context of chitin-chitosan content, does not influence CSH. For C. neoformans, CSH correlated with phagocytosis by natural soil predator Acanthamoeba castellanii Furthermore, capsular binding of the protective antibody (18B7), but not the nonprotective antibody (13F1), altered the CSH of C. neoformans strains. Variability in CSH could be an important characteristic in comparing the biological properties of cryptococcal strains.IMPORTANCE The interaction of a microbial cell with its environment is influenced by the biophysical properties of a cell. The affinity of the cell surface for water, defined by the cell surface hydrophobicity (CSH), is a biophysical parameter that varies among different strains of Cryptococcus neoformans The CSH influences the phagocytosis of the yeast by its natural predator in the soil, the amoeba. Studying variation in biophysical properties like CSH gives us insight into the dynamic host-predator interaction and host-pathogen interaction in a damage-response framework.
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The Inhibition of P-Selectin Reduced Severe Acute Lung Injury in Immunocompromised Mice. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:8430465. [PMID: 32377309 PMCID: PMC7196163 DOI: 10.1155/2020/8430465] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 03/26/2020] [Indexed: 01/05/2023]
Abstract
In an immunocompetent host, excess infiltration of immune cells in the lung is a key factor in infection-induced severe acute lung injury. Kidney transplant patients are immunocompromised by the use of immunosuppressive drugs. Immune cell infiltration in the lung in a renal transplant recipient suffering from pulmonary infection is significantly less than that in an immunocompetent host; however, the extent of lung injury in renal transplant patients is more serious than that in immunocompetent hosts. Therefore, we explored the role of platelet activation in a Klebsiella pneumoniae-induced lung injury model with P-selectin gene knockout mice or wild-type mice. Our study suggested that the inhibition of platelets reduced severe acute lung injury and increased survival after acute lung infection in mice. In addition, P-selectin expression on the surface of platelets in mice increased after administration of immunosuppressive drugs, and the extent of lung injury induced by infection decreased in P-selectin gene knockout mice. In conclusion, p-selectin plays a key role in severe acute lung injury in immunocompromised mice by reducing platelet activation and inflammatory processes.
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Kappel L, Münsterkötter M, Sipos G, Escobar Rodriguez C, Gruber S. Chitin and chitosan remodeling defines vegetative development and Trichoderma biocontrol. PLoS Pathog 2020; 16:e1008320. [PMID: 32078661 PMCID: PMC7053769 DOI: 10.1371/journal.ppat.1008320] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 03/03/2020] [Accepted: 01/15/2020] [Indexed: 12/31/2022] Open
Abstract
Fungal parasitism depends on the ability to invade host organisms and mandates adaptive cell wall remodeling to avoid detection and defense reactions by the host. All plant and human pathogens share invasive strategies, which aid to escape the chitin-triggered and chitin-targeted host immune system. Here we describe the full spectrum of the chitin/chitosan-modifying enzymes in the mycoparasite Trichoderma atroviride with a central role in cell wall remodeling. Rapid adaption to a variety of growth conditions, environmental stresses and host defense mechanisms such as oxidative stress depend on the concerted interplay of these enzymes and, ultimately, are necessary for the success of the mycoparasitic attack. To our knowledge, we provide the first in class description of chitin and associated glycopolymer synthesis in a mycoparasite and demonstrate that they are essential for biocontrol. Eight chitin synthases, six chitin deacetylases, additional chitinolytic enzymes, including six chitosanases, transglycosylases as well as accessory proteins are involved in this intricately regulated process. Systematic and biochemical classification, phenotypic characterization and mycoparasitic confrontation assays emphasize the importance of chitin and chitosan assembly in vegetative development and biocontrol in T. atroviride. Our findings critically contribute to understanding the molecular mechanism of chitin synthesis in filamentous fungi and mycoparasites with the overarching goal to selectively exploit the discovered biocontrol strategies.
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Affiliation(s)
- Lisa Kappel
- Institute of Microbiology, University of Innsbruck, Innsbruck, Vienna, Austria
| | - Martin Münsterkötter
- Department of Functional Genomics and Bioinformatics, University of Sopron, Sopron, Hungary
| | - György Sipos
- Department of Functional Genomics and Bioinformatics, University of Sopron, Sopron, Hungary
| | | | - Sabine Gruber
- Institute of Microbiology, University of Innsbruck, Innsbruck, Vienna, Austria
- * E-mail:
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Cryptococcus neoformans Chitin Synthase 3 Plays a Critical Role in Dampening Host Inflammatory Responses. mBio 2020; 11:mBio.03373-19. [PMID: 32071275 PMCID: PMC7029146 DOI: 10.1128/mbio.03373-19] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Cryptococcus neoformans infections are significant causes of morbidity and mortality among AIDS patients and the third most common invasive fungal infection in organ transplant recipients. One of the main interfaces between the fungus and the host is the fungal cell wall. The cryptococcal cell wall is unusual among human-pathogenic fungi in that the chitin is predominantly deacetylated to chitosan. Chitosan-deficient strains of C. neoformans were found to be avirulent and rapidly cleared from the murine lung. Moreover, infection with a chitosan-deficient C. neoformans strain lacking three chitin deacetylases (cda1Δcda2Δcda3Δ) was found to confer protective immunity to a subsequent challenge with a virulent wild-type counterpart. In addition to the chitin deacetylases, it was previously shown that chitin synthase 3 (Chs3) is also essential for chitin deacetylase-mediated formation of chitosan. Mice inoculated with the chs3Δ strain at a dose previously shown to induce protection with the cda1Δcda2Δcda3Δ strain die within 36 h after installation of the organism. Mortality was not dependent on viable fungi, as mice inoculated with a heat-killed preparation of the chs3Δ strain died at the same rate as mice inoculated with a live chs3Δ strain, suggesting that the rapid onset of death was host mediated, likely caused by an overexuberant immune response. Histology, cytokine profiling, and flow cytometry indicate a massive neutrophil influx in the mice inoculated with the chs3Δ strain. Mice depleted of neutrophils survived chs3Δ inoculation, indicating that death was neutrophil mediated. Altogether, these studies lead us to conclude that Chs3, along with chitosan, plays critical roles in dampening cryptococcus-induced host inflammatory responses.IMPORTANCE Cryptococcus neoformans is the most common disseminated fungal pathogen in AIDS patients, resulting in ∼200,000 deaths each year. There is a pressing need for new treatments for this infection, as current antifungal therapy is hampered by toxicity and/or the inability of the host's immune system to aid in resolution of the disease. An ideal target for new therapies is the fungal cell wall. The cryptococcal cell wall is different from the cell walls of many other pathogenic fungi in that it contains chitosan. Strains that have decreased chitosan are less pathogenic and strains that are deficient in chitosan are avirulent and can induce protective responses. In this study, we investigated the host responses to a chs3Δ strain, a chitosan-deficient strain, and found that mice inoculated with the chs3Δ strain all died within 36 h and that death was associated with an aberrant hyperinflammatory immune response driven by neutrophils, indicating that chitosan is critical in modulating the immune response to Cryptococcus.
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Hembach L, Bonin M, Gorzelanny C, Moerschbacher BM. Unique subsite specificity and potential natural function of a chitosan deacetylase from the human pathogen Cryptococcus neoformans. Proc Natl Acad Sci U S A 2020; 117:3551-3559. [PMID: 32015121 PMCID: PMC7035615 DOI: 10.1073/pnas.1915798117] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cryptococcus neoformans is an opportunistic fungal pathogen that infects ∼280,000 people every year, causing >180,000 deaths. The human immune system recognizes chitin as one of the major cell-wall components of invading fungi, but C. neoformans can circumvent this immunosurveillance mechanism by instead exposing chitosan, the partly or fully deacetylated form of chitin. The natural production of chitosans involves the sequential action of chitin synthases (CHSs) and chitin deacetylases (CDAs). C. neoformans expresses four putative CDAs, three of which have been confirmed as functional enzymes that act on chitin in the cell wall. The fourth (CnCda4/Fpd1) is a secreted enzyme with exceptional specificity for d-glucosamine at its -1 subsite, thus preferring chitosan over chitin as a substrate. We used site-specific mutagenesis to reduce the subsite specificity of CnCda4 by converting an atypical isoleucine residue in a flexible loop region to the bulkier or charged residues tyrosine, histidine, and glutamic acid. We also investigated the effect of CnCda4 deacetylation products on human peripheral blood-derived macrophages, leading to a model explaining the function of CnCda4 during infection. We propose that CnCda4 is used for the further deacetylation of chitosans already exposed on the C. neoformans cell wall (originally produced by CnChs3 and CnCda1 to 3) or released from the cell wall as elicitors by human chitinases, thus making the fungus less susceptible to host immunosurveillance. The absence of CnCda4 during infection could therefore promote the faster recognition and elimination of this pathogen.
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Affiliation(s)
- Lea Hembach
- Institute for Biology and Biotechnology of Plants, University of Münster, 48143 Münster, Germany
| | - Martin Bonin
- Institute for Biology and Biotechnology of Plants, University of Münster, 48143 Münster, Germany
| | - Christian Gorzelanny
- Experimental Dermatology, University Medical Centre Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Bruno M Moerschbacher
- Institute for Biology and Biotechnology of Plants, University of Münster, 48143 Münster, Germany;
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Mouyna I, Dellière S, Beauvais A, Gravelat F, Snarr B, Lehoux M, Zacharias C, Sun Y, de Jesus Carrion S, Pearlman E, Sheppard DC, Latgé JP. What Are the Functions of Chitin Deacetylases in Aspergillus fumigatus? Front Cell Infect Microbiol 2020; 10:28. [PMID: 32117802 PMCID: PMC7016196 DOI: 10.3389/fcimb.2020.00028] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 01/15/2020] [Indexed: 11/13/2022] Open
Abstract
Deacetylation of chitin by chitin deacetylases (Cda) results in the formation of chitosan. Chitosan, a polymer of β1,4 linked glucosamine, plays multiple roles in the function of the fungal cell wall, including virulence and evasion of host immune responses. In this study, the roles of chitosan and putative CDAs in cell wall structure and virulence of Aspergillus fumigatus were investigated. Low levels of chitosan were found in the conidial and cell wall of A. fumigatus. Seven putative CDA genes were identified, disrupted and the phenotype of the single mutants and the septuple mutants were investigated. No alterations in fungal cell wall chitosan levels, changes in fungal growth or alterations in virulence were detected in the single or septuple Δcda1-7 mutant strains. Collectively, these results suggest that chitosan is a minority component of the A. fumigatus cell wall, and that the seven candidate Cda proteins do not play major roles in fungal cell wall synthesis or virulence. However, Cda2 is involved in conidiation, suggesting that this enzyme may play a role in N-acetyl-glucosamine metabolism.
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Affiliation(s)
| | - Sarah Dellière
- Infectious Diseases in Global Health Program, Centre for Translational Biology, McGill University Health Centre, Montréal, QC, Canada
| | | | - Fabrice Gravelat
- Infectious Diseases in Global Health Program, Centre for Translational Biology, McGill University Health Centre, Montréal, QC, Canada
- Departments of Microbiology and Immunology, Medicine, McGill University, Montréal, QC, Canada
| | - Brendan Snarr
- Infectious Diseases in Global Health Program, Centre for Translational Biology, McGill University Health Centre, Montréal, QC, Canada
- Departments of Microbiology and Immunology, Medicine, McGill University, Montréal, QC, Canada
| | - Mélanie Lehoux
- Infectious Diseases in Global Health Program, Centre for Translational Biology, McGill University Health Centre, Montréal, QC, Canada
| | - Caitlin Zacharias
- Infectious Diseases in Global Health Program, Centre for Translational Biology, McGill University Health Centre, Montréal, QC, Canada
- Departments of Microbiology and Immunology, Medicine, McGill University, Montréal, QC, Canada
| | - Yan Sun
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH, United States
| | - Steven de Jesus Carrion
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH, United States
| | - Eric Pearlman
- Department of Ophthalmology, University of California, Irvine, Irvine, CA, United States
| | - Donald C. Sheppard
- Infectious Diseases in Global Health Program, Centre for Translational Biology, McGill University Health Centre, Montréal, QC, Canada
- Departments of Microbiology and Immunology, Medicine, McGill University, Montréal, QC, Canada
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Blatzer M, Beauvais A, Henrissat B, Latgé JP. Revisiting Old Questions and New Approaches to Investigate the Fungal Cell Wall Construction. Curr Top Microbiol Immunol 2020; 425:331-369. [PMID: 32418033 DOI: 10.1007/82_2020_209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The beginning of our understanding of the cell wall construction came from the work of talented biochemists in the 70-80's. Then came the era of sequencing. Paradoxically, the accumulation of fungal genomes complicated rather than solved the mystery of cell wall construction, by revealing the involvement of a much higher number of proteins than originally thought. The situation has become even more complicated since it is now recognized that the cell wall is an organelle whose composition continuously evolves with the changes in the environment or with the age of the fungal cell. The use of new and sophisticated technologies to observe cell wall construction at an almost atomic scale should improve our knowledge of the cell wall construction. This essay will present some of the major and still unresolved questions to understand the fungal cell wall biosynthesis and some of these exciting futurist approaches.
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Affiliation(s)
- Michael Blatzer
- Experimental Neuropathology Unit, Institut Pasteur, 25 rue du Docteur Roux, 75015, Paris, France
| | - Anne Beauvais
- Mycology Department, Institut Pasteur, 25 rue du Docteur Roux, 75015, Paris, France
| | - Bernard Henrissat
- Architecture et Fonction des Macromolécules Biologiques, UMR 7257-CNRS & Aix-Marseille Université, 13288, Marseille cedex 9, France.,Department of Biological Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Jean-Paul Latgé
- Institute of Molecular Biology and Biotechnology of the Foundation for Research and Technology Hellas (IMBB-FORTH), Heraklion, Greece.
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Maybruck BT, Lam WC, Specht CA, Ilagan MXG, Donlin MJ, Lodge JK. The Aminoalkylindole BML-190 Negatively Regulates Chitosan Synthesis via the Cyclic AMP/Protein Kinase A1 Pathway in Cryptococcus neoformans. mBio 2019; 10:e02264-19. [PMID: 31848271 PMCID: PMC6918072 DOI: 10.1128/mbio.02264-19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 10/31/2019] [Indexed: 02/06/2023] Open
Abstract
Cryptococcus neoformans can cause fatal meningoencephalitis in patients with AIDS or other immunocompromising conditions. Current antifungals are suboptimal to treat this disease; therefore, novel targets and new therapies are needed. Previously, we have shown that chitosan is a critical component of the cryptococcal cell wall and is required for survival in the mammalian host and that chitosan deficiency results in rapid clearance from the mammalian host. We had also identified several specific proteins that were required for chitosan biosynthesis, and we hypothesize that screening for compounds that inhibit chitosan biosynthesis would identify additional genes/proteins that influence chitosan biosynthesis. To identify these compounds, we developed a robust and novel cell-based flow cytometry screening method to identify small-molecule inhibitors of chitosan production. We screened the ICCB Known Bioactives library and identified 8 compounds that reduced chitosan in C. neoformans We used flow cytometry-based counterscreens and confirmatory screens, followed by a biochemical secondary screen to refine our primary screening hits to 2 confirmed hits. One of the confirmed hits that reduced chitosan content was the aminoalkylindole BML-190, a known inverse agonist of mammalian cannabinoid receptors. We demonstrated that BML-190 likely targets the C. neoformans G-protein-coupled receptor Gpr4 and, via the cyclic AMP (cAMP)/protein kinase A (PKA) signaling pathway, contributes to an intracellular accumulation of cAMP that results in decreased chitosan. Our discovery suggests that this approach could be used to identify additional compounds and pathways that reduce chitosan biosynthesis and could lead to potential novel therapeutics against C. neoformansIMPORTANCECryptococcus neoformans is a fungal pathogen that kills ∼200,000 people every year. The cell wall is an essential organelle that protects fungi from the environment. Chitosan, the deacetylated form of chitin, has been shown to be an essential component of the cryptococcal cell wall during infection of a mammalian host. In this study, we screened a set of 480 compounds, which are known to have defined biological activities, for activity that reduced chitosan production in C. neoformans Two of these compounds were confirmed using an alternative method of measuring chitosan, and one of these was demonstrated to impact the cAMP signal transduction pathway. This work demonstrates that the cAMP pathway regulates chitosan biosynthesis in C. neoformans and validates that this screening approach could be used to find potential antifungal agents.
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Affiliation(s)
- Brian T Maybruck
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Woei C Lam
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Charles A Specht
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Ma Xenia G Ilagan
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Maureen J Donlin
- Department of Biochemistry and Molecular Biology, Saint Louis University, St. Louis, Missouri, USA
| | - Jennifer K Lodge
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
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Hester MM, Lee CK, Abraham A, Khoshkenar P, Ostroff GR, Levitz SM, Specht CA. Protection of mice against experimental cryptococcosis using glucan particle-based vaccines containing novel recombinant antigens. Vaccine 2019; 38:620-626. [PMID: 31699504 DOI: 10.1016/j.vaccine.2019.10.051] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 10/16/2019] [Accepted: 10/17/2019] [Indexed: 11/27/2022]
Abstract
Meningitis due to Cryptococcus neoformans is responsible for upwards of 180,000 deaths worldwide annually, mostly in immunocompromised individuals. Currently there are no licensed fungal vaccines, and even with anti-fungal drug treatment, cryptococcal meningitis is often fatal. Our lab previously demonstrated vaccination with recombinant cryptococcal proteins delivered in glucan particles (GPs) protects mice against an otherwise lethal infection. The aim of the present study was to discover additional cryptococcal antigens affording vaccine-mediated protection. Sixteen proteins, each with evidence of extracellularity, were selected for in vivo testing based on their abundance in protective alkaline extracts of an acapsular C. neoformans strain, their known immunogenicity, and/or their high transcript level during human infection. Candidate antigens were recombinantly expressed in E. coli, purified and loaded into GPs. BALB/c and C57BL/6 mice received three subcutaneous injections of GP-based vaccine, and survival was assessed for 84 days following a lethal orotracheal challenge with strain KN99. As with our six published GP-vaccines, we saw differences in overall protection between mouse strains such that BALB/c mice typically demonstrated better survival than C57BL/6 mice. From these studies, we identified seven new proteins which, when administered as GP-vaccines, protect BALB/c and/or C57BL/6 mice against cryptococcal infection. With these results, we expand the pool of novel protective antigens to eleven proteins and demonstrate the potential for selection of highly transcribed extracellular proteins as vaccine targets. These screens highlight the efficacy of GP-subunit vaccines and identify promising antigens for further testing in anti-cryptococcal, multi-epitope vaccine formulations.
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Affiliation(s)
- Maureen M Hester
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Chrono K Lee
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Ambily Abraham
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Payam Khoshkenar
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Gary R Ostroff
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Stuart M Levitz
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
| | - Charles A Specht
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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Gao F, Zhang BS, Zhao JH, Huang JF, Jia PS, Wang S, Zhang J, Zhou JM, Guo HS. Deacetylation of chitin oligomers increases virulence in soil-borne fungal pathogens. NATURE PLANTS 2019; 5:1167-1176. [PMID: 31636399 DOI: 10.1038/s41477-019-0527-4] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 09/06/2019] [Indexed: 05/23/2023]
Abstract
Soil-borne fungal pathogens that cause crop disease are major threats to agriculture worldwide. Here, we identified a secretory polysaccharide deacetylase (PDA1) from the soil-borne fungus Verticillium dahliae, the most notorious plant pathogen of the Verticillium genus, that facilitates virulence through direct deacetylation of chitin oligomers whose N-acetyl group contributes to host lysine motif (LysM)-containing receptor perception for ligand-triggered immunity. Polysaccharide deacetylases are widely present in fungi, bacteria, insects and marine invertebrates and have been reported to possess diverse functions in developmental processes rather than virulence. A phylogenetics analysis of more than 5,000 fungal proteins with conserved polysaccharide deacetylase domains showed that the V. dahliae PDA1-containing subtree includes a large number of proteins from the Verticillium genus as well as the Fusarium genus, another group of characterized soil-borne fungal pathogens, suggesting that soil-borne fungal pathogens have adopted chitin deacetylation as a major virulence strategy. We showed that a Fusarium PDA1 is required for virulence in cotton plants. This study reveals a substantial virulence function role of polysaccharide deacetylases in pathogenic fungi and demonstrates a subtle mechanism whereby deacetylation of chitin oligomers converts them to ligand-inactive chitosan, representing a common strategy of preventing chitin-triggered host immunity by soil-borne fungal pathogens.
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Affiliation(s)
- Feng Gao
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- College of Agriculture, Shihezi University, Shihezi, China
| | - Bo-Sen Zhang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- College of Agriculture, Shihezi University, Shihezi, China
| | - Jian-Hua Zhao
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Jia-Feng Huang
- College of Agriculture, Shihezi University, Shihezi, China
- Key Laboratory at Universities of Xinjiang Uygur Autonomous Region for Oasis Agricultural Pest Management and Plant Protection Resource Utilization, Shihezi, China
| | - Pei-Song Jia
- College of Agriculture, Shihezi University, Shihezi, China
- Key Laboratory at Universities of Xinjiang Uygur Autonomous Region for Oasis Agricultural Pest Management and Plant Protection Resource Utilization, Shihezi, China
| | - Sheng Wang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Jie Zhang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Jian-Min Zhou
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Hui-Shan Guo
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
- CAS Center for Excellence in Biotic Interactions, University of the Chinese Academy of Sciences, Beijing, China.
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Abstract
Cryptococcus gattii R265 is a hypervirulent fungal strain responsible for the recent outbreak of cryptococcosis in Vancouver Island of British Columbia in Canada. It differs significantly from Cryptococcus neoformans in its natural environment, its preferred site in the mammalian host, and its pathogenesis. Our previous studies of C. neoformans have shown that the presence of chitosan, the deacetylated form of chitin, in the cell wall attenuates inflammatory responses in the host, while its absence induces robust immune responses, which in turn facilitate clearance of the fungus and induces a protective response. The results of the present investigation reveal that the cell wall of C. gattii R265 contains a two- to threefold larger amount of chitosan than that of C. neoformans The genes responsible for the biosynthesis of chitosan are highly conserved in the R265 genome; the roles of the three chitin deacetylases (CDAs) have, however, been modified. To deduce their roles, single and double CDA deletion strains and a triple CDA deletion strain were constructed in a R265 background and were subjected to mammalian infection studies. Unlike C. neoformans where Cda1 has a discernible role in fungal pathogenesis, in strain R265, Cda3 is critical for virulence. Deletion of either CDA3 alone or in combination with another CDA (cda1Δ3Δ or cda2Δ3Δ) or both (cda1Δ2Δ3Δ) rendered the fungus avirulent and cleared from the infected host. Moreover, the cda1Δ2Δ3Δ strain of R265 induced a protective response to a subsequent infection with R265. These studies begin to illuminate the regulation of chitosan biosynthesis of C. gattii and its subsequent effect on fungal virulence.IMPORTANCE The fungal cell wall is an essential organelle whose components provide the first line of defense against host-induced antifungal activity. Chitosan is one of the carbohydrate polymers in the cell wall that significantly affects the outcome of host-pathogen interaction. Chitosan-deficient strains are avirulent, implicating chitosan as a critical virulence factor. C. gattii R265 is an important fungal pathogen of concern due to its ability to cause infections in individuals with no apparent immune dysfunction and an increasing geographical distribution. Characterization of the fungal cell wall and understanding the contribution of individual molecules of the cell wall matrix to fungal pathogenesis offer new therapeutic avenues for intervention. In this report, we show that the C. gattii R265 strain has evolved alternate regulation of chitosan biosynthesis under both laboratory growth conditions and during mammalian infection compared to that of C. neoformans.
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Mast Cell Responses to Viruses and Pathogen Products. Int J Mol Sci 2019; 20:ijms20174241. [PMID: 31480219 PMCID: PMC6747121 DOI: 10.3390/ijms20174241] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 08/20/2019] [Accepted: 08/26/2019] [Indexed: 01/07/2023] Open
Abstract
Mast cells are well accepted as important sentinel cells for host defence against selected pathogens. Their location at mucosal surfaces and ability to mobilize multiple aspects of early immune responses makes them critical contributors to effective immunity in several experimental settings. However, the interactions of mast cells with viruses and pathogen products are complex and can have both detrimental and positive impacts. There is substantial evidence for mast cell mobilization and activation of effector cells and mobilization of dendritic cells following viral challenge. These cells are a major and under-appreciated local source of type I and III interferons following viral challenge. However, mast cells have also been implicated in inappropriate inflammatory responses, long term fibrosis, and vascular leakage associated with viral infections. Progress in combating infection and boosting effective immunity requires a better understanding of mast cell responses to viral infection and the pathogen products and receptors we can employ to modify such responses. In this review, we outline some of the key known responses of mast cells to viral infection and their major responses to pathogen products. We have placed an emphasis on data obtained from human mast cells and aim to provide a framework for considering the complex interactions between mast cells and pathogens with a view to exploiting this knowledge therapeutically. Long-lived resident mast cells and their responses to viruses and pathogen products provide excellent opportunities to modify local immune responses that remain to be fully exploited in cancer immunotherapy, vaccination, and treatment of infectious diseases.
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Hernández-Castellano LE, Moreno-Indias I, Sánchez-Macías D, Morales-delaNuez A, Torres A, Argüello A, Castro N. Sheep and goats raised in mixed flocks have diverse immune status around parturition. J Dairy Sci 2019; 102:8478-8485. [PMID: 31255264 DOI: 10.3168/jds.2019-16731] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 05/06/2019] [Indexed: 01/07/2023]
Abstract
Several physiological and metabolic changes take place in dairy ruminants around parturition (late pregnancy, parturition, and early lactation). Dairy species are genetically selected for their higher milk production compared with non-dairy species. This fact causes a constant stress that impairs the immune status of the animal, with consequences for its welfare and performance. In the present study, we assessed the immune status of high-yield dairy sheep and goats by quantifying IgG and IgM concentrations, as well as chitotriosidase (ChT) and complement system [total complement system (TC) and alternative complement pathway (AC)] activity in blood plasma around parturition. We also measured IgG and IgM concentrations and ChT activity in colostrum and milk during the first 40 d postpartum. The lowest blood IgG concentration was at parturition in both species. We detected no differences in blood IgG concentrations between species. Blood IgM concentrations were constant in both species throughout the study period. However, blood IgM concentrations were greater in sheep than in goats. Blood ChT activity was greater in goats than in sheep, and both species showed constant activity of this enzyme throughout the study period. We observed no differences in complement system (TC and AC) activity between sheep and goats. In addition, both TC and AC activity were constant in both species throughout the experiment. In general, IgG and IgM concentrations were greater in sheep colostrum than in goat colostrum, but these differences disappeared after d 4 (IgG) and d 3 (IgM) postpartum. In both species, the highest IgG and IgM concentrations were measured in colostrum, gradually decreasing during the first days postpartum. Chitotriosidase activity decreased in both species from colostrum to milk, although goats always showed greater ChT activity than sheep. Both sheep and goats seemed to be more susceptible to infectious diseases around parturition. As well, goats showed greater ChT activity in blood, colostrum, and milk than sheep. This fact may give these animals additional protection against parasite and fungal infections.
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Affiliation(s)
| | - Isabel Moreno-Indias
- Unidad de Gestión Clínica de Endocrinología y Nutrición, Laboratorio del Instituto de Investigación Biomédica de Málaga (IBIMA), Hospital Universitario de Málaga (Virgen de la Victoria), Universidad de Málaga, 29010 Málaga, Spain; Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBERObn), 28029 Madrid, Spain
| | - Davinia Sánchez-Macías
- Animal Production and Industrialization Unit, Department of Agroindustrial Engineering, Universidad Nacional de Chimborazo, 060150 Riobamba, Ecuador
| | - Antonio Morales-delaNuez
- Agrobiotechnology Group, Instituto de Productos Naturales y Agrobiología, IPNA, CSIC Spanish Research Council, 38206 La Laguna, Tenerife, Spain
| | - Alexandr Torres
- Instituto Canario de Investigaciones Agrarias, 38200 La Laguna, Tenerife, Spain
| | - Anastasio Argüello
- Animal Production and Biotechnology Group, Institute of Animal Health and Food Safety, Universidad de Las Palmas de Gran Canaria, 35413 Arucas, Gran Canaria, Spain
| | - Noemí Castro
- Animal Production and Biotechnology Group, Institute of Animal Health and Food Safety, Universidad de Las Palmas de Gran Canaria, 35413 Arucas, Gran Canaria, Spain
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Brown HE, Esher SK, Alspaugh JA. Chitin: A "Hidden Figure" in the Fungal Cell Wall. Curr Top Microbiol Immunol 2019; 425:83-111. [PMID: 31807896 DOI: 10.1007/82_2019_184] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Chitin and chitosan are two related polysaccharides that provide important structural stability to fungal cell walls. Often embedded deeply within the cell wall structure, these molecules anchor other components at the cell surface. Chitin-directed organization of the cell wall layers allows the fungal cell to effectively monitor and interact with the external environment. For fungal pathogens, this interaction includes maintaining cellular strategies to avoid excessive detection by the host innate immune system. In turn, mammalian and plant hosts have developed their own strategies to process fungal chitin, resulting in chitin fragments of varying molecular size. The size-dependent differences in the immune activation behaviors of variably sized chitin molecules help to explain how chitin and related chitooligomers can both inhibit and activate host immunity. Moreover, chitin and chitosan have recently been exploited for many biomedical applications, including targeted drug delivery and vaccine development.
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Affiliation(s)
- Hannah E Brown
- Department of Medicine, Department of Molecular Genetics and Microbiology, Duke University School of Medicine, 303 Sands Research Building, DUMC, 102359, Durham, 27710, NC, USA
| | - Shannon K Esher
- Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, LA, USA
| | - J Andrew Alspaugh
- Department of Medicine, Department of Molecular Genetics and Microbiology, Duke University School of Medicine, 303 Sands Research Building, DUMC, 102359, Durham, 27710, NC, USA.
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