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Lightfoot JD, Adams EM, Kamath MM, Wells BL, Fuller KK. Aspergillus fumigatus Hypoxia Adaptation Is Critical for the Establishment of Fungal Keratitis. Invest Ophthalmol Vis Sci 2024; 65:31. [PMID: 38635243 PMCID: PMC11044834 DOI: 10.1167/iovs.65.4.31] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Accepted: 03/15/2024] [Indexed: 04/19/2024] Open
Abstract
Purpose The poor visual outcomes associated with fungal keratitis (FK) underscore a need to identify fungal pathways that can serve as novel antifungal targets. In this report, we investigated whether hypoxia develops in the FK cornea and, by extension, if fungal hypoxia adaptation is essential for virulence in this setting. Methods C57BL/6J mice were inoculated with Aspergillus fumigatus and Fusarium solani var. petroliphilum via topical overlay or intrastromal injection. At various time points post-inoculation (p.i.), animals were injected with pimonidazole for the detection of tissue hypoxia through immunofluorescence imaging. The A. fumigatus srbA gene was deleted through Cas9-mediated homologous recombination and its virulence was assessed in the topical infection model using slit-lamp microscopy and optical coherence tomography (OCT). Results Topical inoculation with A. fumigatus resulted in diffuse pimonidazole staining across the epithelial and endothelial layers within 6 hours. Stromal hypoxia was evident by 48 hours p.i., which corresponded to leukocytic infiltration. Intrastromal inoculation with either A. fumigatus or F. solani similarly led to diffuse staining patterns across all corneal cell layers. The A. fumigatus srbA deletion mutant was unable to grow at oxygen levels below 3% in vitro, and corneas inoculated with the mutant failed to develop signs of corneal opacification, inflammation, or fungal burden. Conclusions These results suggest that fungal antigen rapidly drives the development of corneal hypoxia, thus rendering fungal SrbA or related pathways essential for the establishment of infection. Such pathways may therefore serve as targets for novel antifungal intervention.
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Affiliation(s)
- Jorge D. Lightfoot
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States
| | - Emily M. Adams
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States
| | - Manali M. Kamath
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States
| | - Becca L. Wells
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States
| | - Kevin K. Fuller
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States
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2
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Henry M, Khemiri I, Tebbji F, Abu-Helu R, Vincent AT, Sellam A. Manganese homeostasis modulates fungal virulence and stress tolerance in Candida albicans. mSphere 2024; 9:e0080423. [PMID: 38380913 PMCID: PMC10964418 DOI: 10.1128/msphere.00804-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 01/31/2024] [Indexed: 02/22/2024] Open
Abstract
Due to the scarcity of transition metals within the human host, fungal pathogens have evolved sophisticated mechanisms to uptake and utilize these micronutrients at the infection interface. While considerable attention was turned to iron and copper acquisition mechanisms and their importance in fungal fitness, less was done regarding either the role of manganese (Mn) in infectious processes or the cellular mechanism by which fungal cells achieve their Mn-homeostasis. Here, we undertook transcriptional profiling in the pathogenic fungus Candida albicans experiencing both Mn starvation and excess to capture biological processes that are modulated by this metal. We uncovered that Mn scarcity influences diverse processes associated with fungal fitness including invasion of host cells and antifungal sensitivity. We show that Mn levels influence the abundance of iron and zinc emphasizing the complex crosstalk between metals. The deletion of SMF12, a member of Mn Nramp transporters, confirmed its contribution to Mn uptake. smf12 was unable to form hyphae and damage host cells and exhibited sensitivity to azoles. We found that the unfolded protein response (UPR), likely activated by decreased glycosylation under Mn limitation, was required to recover growth when cells were shifted from an Mn-starved to an Mn-repleted medium. RNA-seq profiling of cells exposed to Mn excess revealed that UPR was also activated. Furthermore, the UPR signaling axis Ire1-Hac1 was required to bypass Mn toxicity. Collectively, this study underscores the importance of Mn homeostasis in fungal virulence and comprehensively provides a portrait of biological functions that are modulated by Mn in a fungal pathogen. IMPORTANCE Transition metals such as manganese provide considerable functionality across biological systems as they are used as cofactors for many catalytic enzymes. The availability of manganese is very limited inside the human body. Consequently, pathogenic microbes have evolved sophisticated mechanisms to uptake this micronutrient inside the human host to sustain their growth and cause infections. Here, we undertook a comprehensive approach to understand how manganese availability impacts the biology of the prevalent fungal pathogen, Candida albicans. We uncovered that manganese homeostasis in this pathogen modulates different biological processes that are essential for host infection which underscores the value of targeting fungal manganese homeostasis for potential antifungal therapeutics development.
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Affiliation(s)
- Manon Henry
- Montreal Heart Institute/Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada
- Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Inès Khemiri
- Montreal Heart Institute/Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada
- Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Faiza Tebbji
- Montreal Heart Institute/Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada
| | - Rasmi Abu-Helu
- Department of Medical Laboratory Sciences, Faculty of Health Professions, Al-Quds University, Jerusalem, Palestine
| | - Antony T. Vincent
- Department of Animal Sciences, Université Laval, Quebec City, Québec, Canada
| | - Adnane Sellam
- Montreal Heart Institute/Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada
- Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
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3
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Li D, Song F, Mengiste T. Editorial: Molecular biology of plant-fungal interactions. Front Plant Sci 2024; 15:1392149. [PMID: 38504904 PMCID: PMC10949945 DOI: 10.3389/fpls.2024.1392149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 02/28/2024] [Indexed: 03/21/2024]
Affiliation(s)
- Dayong Li
- Ministry of Agriculture and Rural Affairs Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, Zhejiang University, Hangzhou, China
- State Key Laboratory for Rice Biology and Breeding, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Fengming Song
- Ministry of Agriculture and Rural Affairs Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, Zhejiang University, Hangzhou, China
- State Key Laboratory for Rice Biology and Breeding, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Tesfaye Mengiste
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, United States
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4
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James MR, Aufiero MA, Vesely EM, Dhingra S, Liu KW, Hohl TM, Cramer RA. Aspergillus fumigatus cytochrome c impacts conidial survival during sterilizing immunity. mSphere 2023; 8:e0030523. [PMID: 37823656 PMCID: PMC10871163 DOI: 10.1128/msphere.00305-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 08/29/2023] [Indexed: 10/13/2023] Open
Abstract
IMPORTANCE Aspergillus fumigatus can cause a life-threatening infection known as invasive pulmonary aspergillosis (IPA), which is marked by fungus-attributable mortality rates of 20%-30%. Individuals at risk for IPA harbor genetic mutations or incur pharmacologic defects that impair myeloid cell numbers and/or function, exemplified by bone marrow transplant recipients, patients that receive corticosteroid therapy, or patients with chronic granulomatous disease (CGD). However, treatments for Aspergillus infections remain limited, and resistance to the few existing drug classes is emerging. Recently, the World Health Organization classified A. fumigatus as a critical priority fungal pathogen. Our cell death research identifies an important aspect of fungal biology that impacts susceptibility to leukocyte killing. Furthering our understanding of mechanisms that mediate the outcome of fungal-leukocyte interactions will increase our understanding of both the underlying fungal biology governing cell death and innate immune evasion strategies utilized during mammalian infection pathogenesis. Consequently, our studies are a critical step toward leveraging these mechanisms for novel therapeutic advances.
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Affiliation(s)
- Matthew R. James
- Department of Microbiology and Immunology, Geisel School of Medicine, Dartmouth, Hanover, New Hampshire, USA
| | - Mariano A. Aufiero
- Louis V Gerstner Jr. Graduate School of Biomedical Sciences, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Elisa M. Vesely
- Department of Microbiology and Immunology, Geisel School of Medicine, Dartmouth, Hanover, New Hampshire, USA
| | - Sourabh Dhingra
- Department of Microbiology and Immunology, Geisel School of Medicine, Dartmouth, Hanover, New Hampshire, USA
| | - Ko-Wei Liu
- Department of Microbiology and Immunology, Geisel School of Medicine, Dartmouth, Hanover, New Hampshire, USA
| | - Tobias M. Hohl
- Louis V Gerstner Jr. Graduate School of Biomedical Sciences, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, New York, USA
- Infectious Disease Service, Department of Medicine, Memorial Hospital, New York, New York, USA
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Robert A. Cramer
- Department of Microbiology and Immunology, Geisel School of Medicine, Dartmouth, Hanover, New Hampshire, USA
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5
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Dornelles G, Araújo GRDS, Rodrigues M, Alves V, Almeida-Paes R, Frases S. Comparative Analysis of Capsular and Secreted Polysaccharides Produced by Rhodotorula mucilaginosa and Cryptococcus neoformans. J Fungi (Basel) 2023; 9:1124. [PMID: 37998929 PMCID: PMC10672113 DOI: 10.3390/jof9111124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 11/13/2023] [Accepted: 11/17/2023] [Indexed: 11/25/2023] Open
Abstract
Fungal infections are a global public health challenge, especially among immunocompromised patients. Basidiomycetous yeasts, such as Rhodotorula mucilaginosa, have emerged as opportunistic pathogens, but have received less attention than Cryptococcus neoformans. This study aimed to characterize the polysaccharides of R. mucilaginosa and compare them with those of C. neoformans, analyzing their clinical implications. Comprehensive physicochemical, mechanical, and ultrastructural analyses of polysaccharides from both species were performed, revealing correlations with virulence and pathogenicity. R. mucilaginosa cells are surrounded by a capsule smaller than that produced by C. neoformans, but with similar polysaccharides. Those polysaccharides are also secreted by R. mucilaginosa. Cross-reactivity with R. mucilaginosa was observed in a diagnostic C. neoformans antigen test, using both in vitro and in vivo samples, highlighting the need for more reliable tests. Some R. mucilaginosa strains exhibited virulence comparable to that of C. neoformans in an invertebrate experimental model (Tenebrio molitor). This study contributes to a deeper understanding of yeast pathogenicity and virulence, highlighting the need for more accurate diagnostic tests to improve the differential diagnosis of infections caused by basidiomycetous yeasts.
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Affiliation(s)
- Gustavo Dornelles
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil; (G.D.); (G.R.d.S.A.); (M.R.); (V.A.)
| | - Glauber R. de S. Araújo
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil; (G.D.); (G.R.d.S.A.); (M.R.); (V.A.)
| | - Marcus Rodrigues
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil; (G.D.); (G.R.d.S.A.); (M.R.); (V.A.)
| | - Vinicius Alves
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil; (G.D.); (G.R.d.S.A.); (M.R.); (V.A.)
| | - Rodrigo Almeida-Paes
- Laboratório de Micologia, Instituto Nacional de Infectologia Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro 21040-900, Brazil;
- Rede Micologia RJ, Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ), Rio de Janeiro 21040-360, Brazil
| | - Susana Frases
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil; (G.D.); (G.R.d.S.A.); (M.R.); (V.A.)
- Rede Micologia RJ, Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ), Rio de Janeiro 21040-360, Brazil
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6
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Zou J, Jiang C, Qiu S, Duan G, Wang G, Li D, Yu S, Zhao D, Sun W. An Ustilaginoidea virens glycoside hydrolase 42 protein is an essential virulence factor and elicits plant immunity as a PAMP. Mol Plant Pathol 2023; 24:1414-1429. [PMID: 37452482 PMCID: PMC10576179 DOI: 10.1111/mpp.13377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 06/03/2023] [Accepted: 06/22/2023] [Indexed: 07/18/2023]
Abstract
Rice false smut, caused by the ascomycete fungus Ustilaginoidea virens, which infects rice florets before heading, severely threatens rice grain yield and quality worldwide. The U. virens genome encodes a number of glycoside hydrolase (GH) proteins. So far, the functions of these GHs in U. virens are largely unknown. In this study, we identified a GH42 protein secreted by U. virens, named UvGHF1, that exhibits β-galactosidase activity. UvGHF1 not only functions as an essential virulence factor during U. virens infection, but also serves as a pathogen-associated molecular pattern (PAMP) in Nicotiana benthamiana and rice. The PAMP activity of UvGHF1 is independent of its β-galactosidase activity. Moreover, UvGHF1 triggers cell death in N. benthamiana in a BAK1-dependent manner. Ectopic expression of UvGHF1 in rice induces pattern-triggered immunity and enhances rice resistance to fungal and bacterial diseases. RNA-seq analysis revealed that UvGHF1 expression in rice not only activates expression of many defence-related genes encoding leucine-rich repeat receptor-like kinases and WRKY and ERF transcription factors, but also induces diterpenoid biosynthesis and phenylpropanoid biosynthesis pathways. Therefore, UvGHF1 contributes to U. virens virulence, but is also recognized by the rice surveillance system to trigger plant immunity.
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Affiliation(s)
- Jiaying Zou
- College of Plant ProtectionJilin Agricultural UniversityChangchunChina
| | - Chunquan Jiang
- College of Plant ProtectionJilin Agricultural UniversityChangchunChina
| | - Shanshan Qiu
- Department of Plant PathologyChina Agricultural UniversityBeijingChina
| | - Guohua Duan
- College of Plant ProtectionJilin Agricultural UniversityChangchunChina
| | - Guanqun Wang
- College of Plant ProtectionJilin Agricultural UniversityChangchunChina
| | - Dayong Li
- College of Plant ProtectionJilin Agricultural UniversityChangchunChina
| | - Siwen Yu
- College of Plant ProtectionJilin Agricultural UniversityChangchunChina
| | - Dan Zhao
- College of Plant ProtectionJilin Agricultural UniversityChangchunChina
| | - Wenxian Sun
- College of Plant ProtectionJilin Agricultural UniversityChangchunChina
- Department of Plant PathologyChina Agricultural UniversityBeijingChina
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7
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Abstract
Fungal-mediated disease progression and antifungal drug efficacy are significantly impacted by the dynamic infection microenvironment. At the site of infection, oxygen often becomes limiting and induces a hypoxia response in both the fungal pathogen and host cells. The fungal hypoxia response impacts several important aspects of fungal biology that contribute to pathogenesis, virulence, antifungal drug susceptibility, and ultimately infection outcomes. In this review, we summarize recent advances in understanding the molecular mechanisms of the hypoxia response in the most common human fungal pathogens, discuss potential therapeutic opportunities, and highlight important areas for future research.
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Affiliation(s)
- Charles Puerner
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA;
| | - Sandeep Vellanki
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA;
| | - Julianne L Strauch
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA;
- Department of Biology, Dartmouth College, Hanover, New Hampshire, USA
| | - Robert A Cramer
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA;
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8
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Martins C, Piontkivska D, Mil-Homens D, Guedes P, Jorge JMP, Brinco J, Bárria C, Santos ACF, Barras R, Arraiano C, Fialho A, Goldman GH, Silva Pereira C. Increased Production of Pathogenic, Airborne Fungal Spores upon Exposure of a Soil Mycobiota to Chlorinated Aromatic Hydrocarbon Pollutants. Microbiol Spectr 2023; 11:e0066723. [PMID: 37284774 PMCID: PMC10434042 DOI: 10.1128/spectrum.00667-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 05/22/2023] [Indexed: 06/08/2023] Open
Abstract
Organic pollutants are omnipresent and can penetrate all environmental niches. We evaluated the hypothesis that short-term (acute) exposure to aromatic hydrocarbon pollutants could increase the potential for fungal virulence. Specifically, we analyzed whether pentachlorophenol and triclosan pollution results in the production of airborne fungal spores with greater virulence than those derived from an unpolluted (Control) condition. Each pollutant altered the composition of the community of airborne spores compared to the control, favoring an increase in strains with in vivo infection capacity (the wax moth Galleria mellonella was used as an infection model). Fungi subsisting inside larvae at 72 h postinjection with airborne spore inocula collected in polluted and unpolluted conditions exhibited comparable diversity (mainly within Aspergillus fumigatus). Several virulent Aspergillus strains were isolated from larvae infected with the airborne spores produced in a polluted environment. Meanwhile, strains isolated from larvae injected with spores from the control, including one A. fumigatus strain, showed no virulence. Potential pathogenicity increased when two Aspergillus virulent strains were assembled, suggesting the existence of synergisms that impact pathogenicity. None of the observed taxonomic or functional traits could separate the virulent from the avirulent strains. Our study emphasizes pollution stress as a possible driver of phenotypic adaptations that increase Aspergillus pathogenicity, as well as the need to better understand the interplay between pollution and fungal virulence. IMPORTANCE Fungi colonizing soil and organic pollutants often meet. The consequences of this encounter constitute an outstanding question. We scrutinized the potential for virulence of airborne fungal spores produced under unpolluted and polluted scenarios. The airborne spores showed increased diversity of strains with higher infection capacity in Galleria mellonella whenever pollution is present. Inside the larvae injected with either airborne spore community, the surviving fungi demonstrated a similar diversity, mainly within Aspergillus fumigatus. However, the isolated Aspergillus strains greatly differ since virulence was only observed for those associated with a polluted environment. The interplay between pollution and fungal virulence still hides many unresolved questions, but the encounter is costly: pollution stress promotes phenotypic adaptations that may increase Aspergillus pathogenicity.
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Affiliation(s)
- Celso Martins
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Daryna Piontkivska
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Dalila Mil-Homens
- Institute for Bioengineering and Biosciences and Institute for Health and Bioeconomy, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal
- Department of Bioengineering, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal
| | - Paula Guedes
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
- CENSE (Center for Environmental and Sustainability Research)/CHANGE (Global Change and Sustainability Institute), NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
| | - João M. P. Jorge
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - João Brinco
- CENSE (Center for Environmental and Sustainability Research)/CHANGE (Global Change and Sustainability Institute), NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
| | - Cátia Bárria
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Ariana C. F. Santos
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Ricardo Barras
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Cecília Arraiano
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Arsénio Fialho
- Institute for Bioengineering and Biosciences and Institute for Health and Bioeconomy, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal
- Department of Bioengineering, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal
| | - Gustavo H. Goldman
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Cristina Silva Pereira
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
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9
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Pierre JF, Peters BM, La Torre D, Sidebottom AM, Tao Y, Zhu X, Cham CM, Wang L, Kambal A, Harris KG, Silva JF, Zaborina O, Alverdy JC, Herzog H, Witchley J, Noble SM, Leone VA, Chang EB. Peptide YY: A Paneth cell antimicrobial peptide that maintains Candida gut commensalism. Science 2023; 381:502-508. [PMID: 37535745 PMCID: PMC10876062 DOI: 10.1126/science.abq3178] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 06/02/2023] [Indexed: 08/05/2023]
Abstract
The mammalian gut secretes a family of multifunctional peptides that affect appetite, intestinal secretions, and motility whereas others regulate the microbiota. We have found that peptide YY (PYY1-36), but not endocrine PYY3-36, acts as an antimicrobial peptide (AMP) expressed by gut epithelial paneth cells (PC). PC-PYY is packaged into secretory granules and is secreted into and retained by surface mucus, which optimizes PC-PYY activity. Although PC-PYY shows some antibacterial activity, it displays selective antifungal activity against virulent Candida albicans hyphae-but not the yeast form. PC-PYY is a cationic molecule that interacts with the anionic surfaces of fungal hyphae to cause membrane disruption and transcriptional reprogramming that selects for the yeast phenotype. Hence, PC-PYY is an antifungal AMP that contributes to the maintenance of gut fungal commensalism.
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Affiliation(s)
- Joseph F Pierre
- Department of Medicine, University of Chicago, Chicago, IL, USA
- Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI, USA
| | - Brian M Peters
- Department of Clinical Pharmacy and Translational Science, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Diana La Torre
- Department of Medicine, University of Chicago, Chicago, IL, USA
| | | | - Yun Tao
- Department of Medicine, University of Chicago, Chicago, IL, USA
| | - Xiaorong Zhu
- Department of Medicine, University of Chicago, Chicago, IL, USA
| | - Candace M Cham
- Department of Medicine, University of Chicago, Chicago, IL, USA
| | - Ling Wang
- Department of Medicine, University of Chicago, Chicago, IL, USA
| | - Amal Kambal
- Department of Medicine, University of Chicago, Chicago, IL, USA
| | - Katharine G Harris
- Department of Medicine, University of Chicago, Chicago, IL, USA
- Department of Biology, Franklin College, Franklin, IN, USA
| | - Julian F Silva
- Department of Medicine, University of Chicago, Chicago, IL, USA
| | - Olga Zaborina
- Department of Surgery, University of Chicago, Chicago, IL, USA
| | - John C Alverdy
- Department of Surgery, University of Chicago, Chicago, IL, USA
| | | | - Jessica Witchley
- Department of Microbiology and Immunology, School of Medicine, University of California San Francisco, San Francisco, CA, USA
- Department of Molecular and Cell Biology, Immunology and Molecular Medicine Division, University of California-Berkeley, CA, USA
| | - Suzanne M Noble
- Department of Microbiology and Immunology, School of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Vanessa A Leone
- Department of Medicine, University of Chicago, Chicago, IL, USA
- Department of Animal & Dairy Sciences, University of Wisconsin-Madison, Madison, WI, USA
| | - Eugene B Chang
- Department of Medicine, University of Chicago, Chicago, IL, USA
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10
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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. Front Fungal Biol 2023; 4:1183291. [PMID: 37538303 PMCID: PMC10399910 DOI: 10.3389/ffunb.2023.1183291] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Bowring BG, Sethiya P, Desmarini D, Lev S, Tran Le L, Bahn YS, Lee SH, Toh-E A, Proschogo N, Savage T, Djordjevic JT. Dysregulating PHO Signaling via the CDK Machinery Differentially Impacts Energy Metabolism, Calcineurin Signaling, and Virulence in C. neoformans. mBio 2023; 14:e0355122. [PMID: 37017534 PMCID: PMC10127591 DOI: 10.1128/mbio.03551-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2023] Open
Abstract
Fungal pathogens uniquely regulate phosphate homeostasis via the cyclin-dependent kinase (CDK) signaling machinery of the phosphate acquisition (PHO) pathway (Pho85 kinase-Pho80 cyclin-CDK inhibitor Pho81), providing drug-targeting opportunities. Here, we investigate the impact of a PHO pathway activation-defective Cryptococcus neoformans mutant (pho81Δ) and a constitutively activated PHO pathway mutant (pho80Δ) on fungal virulence. Irrespective of phosphate availability, the PHO pathway was derepressed in pho80Δ with all phosphate acquisition pathways upregulated and much of the excess phosphate stored as polyphosphate (polyP). Elevated phosphate in pho80Δ coincided with elevated metal ions, metal stress sensitivity, and a muted calcineurin response, all of which were ameliorated by phosphate depletion. In contrast, metal ion homeostasis was largely unaffected in the pho81Δ mutant, and Pi, polyP, ATP, and energy metabolism were reduced, even under phosphate-replete conditions. A similar decline in polyP and ATP suggests that polyP supplies phosphate for energy production even when phosphate is available. Using calcineurin reporter strains in the wild-type, pho80Δ, and pho81Δ background, we also demonstrate that phosphate deprivation stimulates calcineurin activation, most likely by increasing the bioavailability of calcium. Finally, we show that blocking, as opposed to permanently activating, the PHO pathway reduced fungal virulence in mouse infection models to a greater extent and that this is most likely attributable to depleted phosphate stores and ATP, and compromised cellular bioenergetics, irrespective of phosphate availability. IMPORTANCE Invasive fungal diseases cause more than 1.5 million deaths per year, with an estimated 181,000 of these deaths attributable to Cryptococcal meningitis. Despite the high mortality, treatment options are limited. In contrast to humans, fungal cells maintain phosphate homeostasis via a CDK complex, providing drug-targeting opportunities. To investigate which CDK components are the best targets for potential antifungal therapy, we used strains with a constitutively active (pho80Δ) and an activation-defective (pho81Δ) PHO pathway, to investigate the impact of dysregulated phosphate homeostasis on cellular function and virulence. Our studies suggest that inhibiting the function of Pho81, which has no human homologue, would have the most detrimental impact on fungal growth in the host due to depletion of phosphate stores and ATP, irrespective of phosphate availability in the host.
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Affiliation(s)
- Bethany Grace Bowring
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Westmead, NSW, Australia
- Sydney Institute for Infectious Diseases, University of Sydney, Sydney, NSW, Australia
| | - Pooja Sethiya
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Westmead, NSW, Australia
- Sydney Institute for Infectious Diseases, University of Sydney, Sydney, NSW, Australia
| | - Desmarini Desmarini
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Westmead, NSW, Australia
- Sydney Institute for Infectious Diseases, University of Sydney, Sydney, NSW, Australia
| | - Sophie Lev
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Westmead, NSW, Australia
- Sydney Institute for Infectious Diseases, University of Sydney, Sydney, NSW, Australia
| | - Lisa Tran Le
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Westmead, NSW, Australia
- Sydney Institute for Infectious Diseases, University of Sydney, Sydney, NSW, Australia
| | - Yong-Sun Bahn
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea
| | - Seung-Heon Lee
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea
| | - Akio Toh-E
- Medical Mycology Research Center, Chiba University, Chiba City, Chiba, Japan
| | | | - Tom Savage
- School of Geosciences, University of Sydney, Sydney, NSW, Australia
| | - Julianne Teresa Djordjevic
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Westmead, NSW, Australia
- Sydney Institute for Infectious Diseases, University of Sydney, Sydney, NSW, Australia
- Western Sydney Local Health District, Westmead, NSW, Australia
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12
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Cui C, Wang Y, Li Y, Sun P, Jiang J, Zhou H, Liu J, Wang S. Expression of mosquito miRNAs in entomopathogenic fungus induces pathogen-mediated host RNA interference and increases fungal efficacy. Cell Rep 2022; 41:111527. [PMID: 36288711 DOI: 10.1016/j.celrep.2022.111527] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Revised: 08/18/2022] [Accepted: 09/28/2022] [Indexed: 11/21/2022] Open
Abstract
The growing threat of insecticide resistance prompts the urgent need to develop additional tools for mosquito control. Entomopathogenic fungi provide an eco-friendly alternative to chemical insecticides. One limitation to the use of mycoinsecticides is their relatively low virulence. Here, we report an approach for suppressing mosquito immunity and increasing fungal virulence. We engineered Beauveria bassiana to express Aedes immunosuppressive microRNAs (miRNAs) to induce host RNA interference (RNAi) immune responses. We show that engineered strains can produce and deliver the miRNAs into host cells to activate cross-kingdom RNAi during infection and suppress mosquito immunity by targeting multiple host genes, thereby dramatically increasing fungal virulence against Aedes aegypti and Galleria mellonella larvae. Importantly, expressing host miRNAs also significantly increases fungal virulence against insecticide-resistant mosquitoes, creating potential for insecticide-resistance management. This pathogen-mediated RNAi (pmRNAi)-based approach provides an innovative strategy to enhance the efficacy of fungal insecticides and eliminate the likelihood of resistance development.
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13
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Lerer V, Shlezinger N. Inseparable companions: Fungal viruses as regulators of fungal fitness and host adaptation. Front Cell Infect Microbiol 2022; 12:1020608. [PMID: 36310864 PMCID: PMC9606465 DOI: 10.3389/fcimb.2022.1020608] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 09/28/2022] [Indexed: 08/01/2023] Open
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14
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Chen MM, Yang SR, Wang J, Fang YL, Peng YL, Fan J. Fungal oxysterol-binding protein-related proteins promote pathogen virulence and activate plant immunity. J Exp Bot 2022; 73:2125-2141. [PMID: 34864987 DOI: 10.1093/jxb/erab530] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 12/02/2021] [Indexed: 06/13/2023]
Abstract
Oxysterol-binding protein-related proteins (ORPs) are a conserved class of lipid transfer proteins that are closely involved in multiple cellular processes in eukaryotes, but their roles in plant-pathogen interactions are mostly unknown. We show that transient expression of ORPs of Magnaporthe oryzae (MoORPs) in Nicotiana benthamina plants triggered oxidative bursts and cell death; treatment of tobacco Bright Yellow-2 suspension cells with recombinant MoORPs elicited the production of reactive oxygen species. Despite ORPs being normally described as intracellular proteins, we detected MoORPs in fungal culture filtrates and intercellular fluids from barley plants infected with the fungus. More importantly, infiltration of Arabidopsis plants with recombinant Arabidopsis or fungal ORPs activated oxidative bursts, callose deposition, and PR1 gene expression, and enhanced plant disease resistance, implying that ORPs may function as endogenous and exogenous danger signals triggering plant innate immunity. Extracellular application of fungal ORPs exerted an opposite impact on salicylic acid and jasmonic acid/ethylene signaling pathways. Brassinosteroid Insensitive 1-associated Kinase 1 was dispensable for the ORP-activated defense. Besides, simultaneous knockout of MoORP1 and MoORP3 abolished fungal colony radial growth and conidiation, whereas double knockout of MoORP1 and MoORP2 compromised fungal virulence on barley and rice plants. These observations collectively highlight the multifaceted role of MoORPs in the modulation of plant innate immunity and promotion of fungal development and virulence in M. oryzae.
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Affiliation(s)
- Meng-Meng Chen
- Department of Plant Pathology, MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
| | - Si-Ru Yang
- Department of Plant Pathology, MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
| | - Jian Wang
- Department of Plant Pathology, MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
| | - Ya-Li Fang
- Department of Plant Pathology, MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
| | - You-Liang Peng
- Department of Plant Pathology, MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, China
| | - Jun Fan
- Department of Plant Pathology, MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
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15
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Jiang L, Zhang S, Su J, Peck SC, Luo L. Protein Kinase Signaling Pathways in Plant- Colletotrichum Interaction. Front Plant Sci 2022; 12:829645. [PMID: 35126439 PMCID: PMC8811371 DOI: 10.3389/fpls.2021.829645] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 12/27/2021] [Indexed: 06/14/2023]
Abstract
Anthracnose is a fungal disease caused by members of Colletotrichum that affect a wide range of crop plants. Strategies to improve crop resistance are needed to reduce the yield losses; and one strategy is to manipulate protein kinases that catalyze reversible phosphorylation of proteins regulating both plant immune responses and fungal pathogenesis. Hence, in this review, we present a summary of the current knowledge of protein kinase signaling pathways in plant-Colletotrichum interaction as well as the relation to a more general understanding of protein kinases that contribute to plant immunity and pathogen virulence. We highlight the potential of combining genomic resources and phosphoproteomics research to unravel the key molecular components of plant-Colletotrichum interactions. Understanding the molecular interactions between plants and Colletotrichum would not only facilitate molecular breeding of resistant cultivars but also help the development of novel strategies for controlling the anthracnose disease.
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Affiliation(s)
- Lingyan Jiang
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, College of Tropical Crops, Hainan University, Haikou, China
| | - Shizi Zhang
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, College of Tropical Crops, Hainan University, Haikou, China
| | - Jianbin Su
- Division of Plant Sciences, Interdisciplinary Plant Group, Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, United States
| | - Scott C. Peck
- Division of Biochemistry, Interdisciplinary Plant Group, Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, United States
| | - Lijuan Luo
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, College of Tropical Crops, Hainan University, Haikou, China
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16
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Zhang M, Liang G, Dong J, Zheng H, Mei H, Zha F, Liu W. A thermal adaptation landscape related to virulence in Mucor irregularis transcriptional profiles. Mycoses 2021; 65:374-387. [PMID: 34779032 DOI: 10.1111/myc.13394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 11/08/2021] [Accepted: 11/08/2021] [Indexed: 11/28/2022]
Abstract
OBJECTIVES Our study aimed to better understand the different thermal adaptation in Mucor irregularis (M. irregularis) strains under high temperature and the involved virulence-related genes, and to offer more appropriate explanation for the diverse pathogenicity of M. irregularis in human infections. METHODS M. irregularis isolates were incubated at 30 and 35°C for Illumina HiSeq technology (RNA-seq), as well as the virulence difference detected through Galleria mellonella infection models. We verified their transcriptional profile with RT-PCR and analysed differentially expressed genes with GO and KEGG annotations. RESULTS All 25 isolates formed the biggest colonies at 28°C and did not grow at 37°C, while were differently inhibited at 22 and 35°C. Six selected M. irregularis displayed virulence in sync with their growth condition at high temperature. From the outcomes of RNA-seq, a total of 1559 differentially expressed genes (FC ≥ 2, FDR < 0.05) were obtained, of which 1021 genes were upregulated, and 538 genes were downregulated. Cell wall structure genes related to Ras-like and GH16 proteins, influx-efflux pumps consist of transmembrane proteins as ABC and MFS proteins, and metabolic genes as DGKɛ and Hsfs, seem to be essential in thermal adaptation and virulence of M. irregularis. CONCLUSION We found some common genes expressed at high temperature, while some others specifically related to M. irregularis isolates with different virulence and thermal adaptation. Further research of genes involved in the pathogenic process is needed for the development of potential targeted antifungal.
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Affiliation(s)
- Meijie Zhang
- Department of Medical Mycology, Institute of Dermatology, Chinese Academy of Medical Science and Peking Union Medical College, Nanjing, China.,Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Nanjing, China.,CAMS Collection Center of Pathogen Microorganisms-D (CAMS-CCPM-D), Nanjing, China
| | - Guanzhao Liang
- Department of Medical Mycology, Institute of Dermatology, Chinese Academy of Medical Science and Peking Union Medical College, Nanjing, China.,Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Nanjing, China.,CAMS Collection Center of Pathogen Microorganisms-D (CAMS-CCPM-D), Nanjing, China
| | - Jiacheng Dong
- Department of Medical Mycology, Institute of Dermatology, Chinese Academy of Medical Science and Peking Union Medical College, Nanjing, China.,Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Nanjing, China.,CAMS Collection Center of Pathogen Microorganisms-D (CAMS-CCPM-D), Nanjing, China
| | - Hailin Zheng
- Department of Medical Mycology, Institute of Dermatology, Chinese Academy of Medical Science and Peking Union Medical College, Nanjing, China.,Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Nanjing, China.,CAMS Collection Center of Pathogen Microorganisms-D (CAMS-CCPM-D), Nanjing, China
| | - Huan Mei
- Department of Medical Mycology, Institute of Dermatology, Chinese Academy of Medical Science and Peking Union Medical College, Nanjing, China.,Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Nanjing, China.,CAMS Collection Center of Pathogen Microorganisms-D (CAMS-CCPM-D), Nanjing, China
| | - Fuxing Zha
- Shanghai BIOZERON Biotechnology Co., Ltd., Shanghai, China
| | - Weida Liu
- Department of Medical Mycology, Institute of Dermatology, Chinese Academy of Medical Science and Peking Union Medical College, Nanjing, China.,Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Nanjing, China.,CAMS Collection Center of Pathogen Microorganisms-D (CAMS-CCPM-D), Nanjing, China.,Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China
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17
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Wang Y, Wear M, Kohli G, Vij R, Giamberardino C, Shah A, Toffaletti DL, Yu CA, Perfect JR, Casadevall A, Xue C. Inositol Metabolism Regulates Capsule Structure and Virulence in the Human Pathogen Cryptococcus neoformans. mBio 2021;:e0279021. [PMID: 34724824 DOI: 10.1128/mBio.02790-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The environmental yeast Cryptococcus neoformans is the most common cause of deadly fungal meningitis in primarily immunocompromised populations. A number of factors contribute to cryptococcal pathogenesis. Among them, inositol utilization has been shown to promote C. neoformans development in nature and invasion of central nervous system during dissemination. The mechanisms of the inositol regulation of fungal virulence remain incompletely understood. In this study, we analyzed inositol-induced capsule growth and the contribution of a unique inositol catabolic pathway in fungal development and virulence. We found that genes involved in the inositol catabolic pathway are highly induced by inositol, and they are also highly expressed in the cerebrospinal fluid of patients with meningoencephalitis. This pathway in C. neoformans contains three genes encoding myo-inositol oxygenases that convert myo-inositol into d-glucuronic acid, a substrate of the pentose phosphate cycle and a component of the polysaccharide capsule. Our mutagenesis analysis demonstrates that inositol catabolism is required for C. neoformans virulence and deletion mutants of myo-inositol oxygenases result in altered capsule growth as well as the polysaccharide structure, including O-acetylation. Our study indicates that the ability to utilize the abundant inositol in the brain may contribute to fungal pathogenesis in this neurotropic fungal pathogen. IMPORTANCE The human pathogen Cryptococcus neoformans is the leading cause of fungal meningitis in primarily immunocompromised populations. Understanding how this environmental organism adapts to the human host to cause deadly infection will guide our development of novel disease control strategies. Our recent studies revealed that inositol utilization by the fungus promotes C. neoformans development in nature and invasion of the central nervous system during infection. The mechanisms of the inositol regulation in fungal virulence remain incompletely understood. In this study, we found that C. neoformans has three genes encoding myo-inositol oxygenase, a key enzyme in the inositol catabolic pathway. Expression of these genes is highly induced by inositol, and they are highly expressed in the cerebrospinal fluid of patients with meningoencephalitis. Our mutagenesis analysis indeed demonstrates that inositol catabolism is required for C. neoformans virulence by altering the growth and structure of polysaccharide capsule, a major virulence factor. Considering the abundance of free inositol and inositol-related metabolites in the brain, our study reveals an important mechanism of host inositol-mediated fungal pathogenesis for this neurotropic fungal pathogen.
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Zhang H, Shen W, Zhang D, Shen X, Wang F, Hsiang T, Liu J, Li G. The bZIP Transcription Factor LtAP1 Modulates Oxidative Stress Tolerance and Virulence in the Peach Gummosis Fungus Lasiodiplodia theobromae. Front Microbiol 2021; 12:741842. [PMID: 34630367 PMCID: PMC8495313 DOI: 10.3389/fmicb.2021.741842] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 08/25/2021] [Indexed: 12/02/2022] Open
Abstract
Lasiodiplodia theobromae is one of the primary causal agents in peach gummosis disease, leading to enormous losses in peach production. In our previous study, a redox-related gene, LtAP1, from the fungus was significantly upregulated in peach shoots throughout infection. Here, we characterized LtAP1, a basic leucine zipper transcription factor, during peach gummosis progression using the CRISPR-Cas9 system and homologous recombination. The results showed that LtAP1-deletion mutant had slower vegetative growth and increased sensitivity to several oxidative and nitrosative stress agents. LtAP1 was highly induced by exogenous oxidants treatment in the L. theobromae wild-type strain. In a pathogenicity test, the deletion mutant showed decreased virulence (reduced size of necrotic lesions, less gum release, and decreased pathogen biomass) on infected peach shoots compared to the wild-type strain. The mutant showed severely reduced transcription levels of genes related to glutaredoxin and thioredoxin in L. theobroame under oxidative stress or during infection, indicating an attenuated capacity for reactive oxygen species (ROS) detoxification. When shoots were treated with an NADPH oxidase inhibitor, the pathogenicity of the mutant was partially restored. Moreover, ROS production and plant defense response were strongly activated in peach shoots infected by the mutant. These results highlight the crucial role of LtAP1 in the oxidative stress response, and further that it acts as an important virulence factor through modulating the fungal ROS-detoxification system and the plant defense response.
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Affiliation(s)
- He Zhang
- Key Laboratory of Horticultural Plant Biology-Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China.,Haikou Experimental Station, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
| | - Wanqi Shen
- Key Laboratory of Horticultural Plant Biology-Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Dongmei Zhang
- Key Laboratory of Horticultural Plant Biology-Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Xingyi Shen
- Key Laboratory of Horticultural Plant Biology-Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Fan Wang
- Jiangxi Oil-tea Camellia, Jiujiang University, Jiujiang, China
| | - Tom Hsiang
- School of Environmental Sciences, University of Guelph, Guelph, ON, Canada
| | - Junwei Liu
- Key Laboratory of Horticultural Plant Biology-Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Guohuai Li
- Key Laboratory of Horticultural Plant Biology-Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China
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Villalobos-Duno HL, Barreto LA, Alvarez-Aular Á, Mora-Montes HM, Lozoya-Pérez NE, Franco B, Lopes-Bezerra LM, Niño-Vega GA. Comparison of Cell Wall Polysaccharide Composition and Structure Between Strains of Sporothrix schenckii and Sporothrix brasiliensis. Front Microbiol 2021; 12:726958. [PMID: 34616384 PMCID: PMC8489378 DOI: 10.3389/fmicb.2021.726958] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 08/24/2021] [Indexed: 12/19/2022] Open
Abstract
Sporothrix schenckii, Sporothrix brasiliensis, and Sporothrix globosa are the main causative agents of sporotrichosis, a human subcutaneous mycosis. Differences in virulence patterns are associated with each species but remain largely uncharacterized. The S. schenckii and S. brasiliensis cell wall composition and virulence are influenced by the culturing media, with little or no influence on S. globosa. By keeping constant the culturing media, we compared the cell wall composition of three S. schenckii and two S. brasiliensis strains, previously described as presenting different virulence levels on a murine model of infection. The cell wall composition of the five Sporothrix spp. strains correlated with the biochemical composition of the cell wall previously reported for the species. However, the rhamnose-to-β-glucan ratio exhibits differences among strains, with an increase in cell wall rhamnose-to-β-glucan ratio as their virulence increased. This relationship can be expressed mathematically, which could be an important tool for the determination of virulence in Sporothrix spp. Also, structural differences in rhamnomannan were found, with longer side chains present in strains with lower virulence reported for both species here studied, adding insight to the importance of this polysaccharide in the pathogenic process of these fungi.
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Affiliation(s)
- Héctor L Villalobos-Duno
- Laboratorio de Micología, Centro de Microbiología y Biología Celular, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela
| | - Laura A Barreto
- Instituto Superior de Formación Docente Salome Ureña, Santo Domingo, Dominican Republic
| | - Álvaro Alvarez-Aular
- Laboratorio de Síntesis Orgánica y Productos Naturales, Centro de Química, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela
| | - Héctor M Mora-Montes
- División de Ciencias Naturales y Exactas, Departamento de Biología, Universidad de Guanajuato, Guanajuato, Mexico
| | - Nancy E Lozoya-Pérez
- División de Ciencias Naturales y Exactas, Departamento de Biología, Universidad de Guanajuato, Guanajuato, Mexico
| | - Bernardo Franco
- División de Ciencias Naturales y Exactas, Departamento de Biología, Universidad de Guanajuato, Guanajuato, Mexico
| | | | - Gustavo A Niño-Vega
- División de Ciencias Naturales y Exactas, Departamento de Biología, Universidad de Guanajuato, Guanajuato, Mexico
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20
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Alaalm L, Crunden JL, Butcher M, Obst U, Whealy R, Williamson CE, O'Brien HE, Schaffitzel C, Ramage G, Spencer J, Diezmann S. Identification and Phenotypic Characterization of Hsp90 Phosphorylation Sites That Modulate Virulence Traits in the Major Human Fungal Pathogen Candida albicans. Front Cell Infect Microbiol 2021; 11:637836. [PMID: 34513723 PMCID: PMC8431828 DOI: 10.3389/fcimb.2021.637836] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 05/24/2021] [Indexed: 01/13/2023] Open
Abstract
The highly conserved, ubiquitous molecular chaperone Hsp90 is a key regulator of cellular proteostasis and environmental stress responses. In human pathogenic fungi, which kill more than 1.6 million patients each year worldwide, Hsp90 governs cellular morphogenesis, drug resistance, and virulence. Yet, our understanding of the regulatory mechanisms governing fungal Hsp90 function remains sparse. Post-translational modifications are powerful components of nature’s toolbox to regulate protein abundance and function. Phosphorylation in particular is critical in many cellular signaling pathways and errant phosphorylation can have dire consequences for the cell. In the case of Hsp90, phosphorylation affects its stability and governs its interactions with co-chaperones and clients. Thereby modulating the cell’s ability to cope with environmental stress. Candida albicans, one of the leading human fungal pathogens, causes ~750,000 life-threatening invasive infections worldwide with unacceptably high mortality rates. Yet, it remains unknown if and how Hsp90 phosphorylation affects C. albicans virulence traits. Here, we show that phosphorylation of Hsp90 is critical for expression of virulence traits. We combined proteomics, molecular evolution analyses and structural modeling with molecular biology to characterize the role of Hsp90 phosphorylation in this non-model pathogen. We demonstrated that phosphorylation negatively affects key virulence traits, such as the thermal stress response, morphogenesis, and drug susceptibility. Our results provide the first record of a specific Hsp90 phosphorylation site acting as modulator of fungal virulence. Post-translational modifications of Hsp90 could prove valuable in future exploitations as antifungal drug targets.
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Affiliation(s)
- Leenah Alaalm
- Department of Biology & Biochemistry, University of Bath, Bath, United Kingdom
| | - Julia L Crunden
- Department of Biology & Biochemistry, University of Bath, Bath, United Kingdom.,School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Mark Butcher
- School of Medicine, Dentistry and Nursing, University of Glasgow, Glasgow, United Kingdom
| | - Ulrike Obst
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Ryann Whealy
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | | | - Heath E O'Brien
- MRC Centre for Neuropsychiatric Genetics & Genomics, Division of Psychological Medicine & Clinical Neurosciences, Cardiff University, Cardiff, United Kingdom
| | | | - Gordon Ramage
- School of Medicine, Dentistry and Nursing, University of Glasgow, Glasgow, United Kingdom
| | - James Spencer
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Stephanie Diezmann
- Department of Biology & Biochemistry, University of Bath, Bath, United Kingdom.,School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
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21
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Lyons N, Softley I, Balfour A, Williamson C, O'Brien HE, Shetty AC, Bruno VM, Diezmann S. Tobacco Hornworm ( Manduca sexta) caterpillars as a novel host model for the study of fungal virulence and drug efficacy. Virulence 2021; 11:1075-1089. [PMID: 32842847 PMCID: PMC7549948 DOI: 10.1080/21505594.2020.1806665] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The two leading yeast pathogens of humans, Candida albicans and Cryptococcus neoformans, cause systemic infections in >1.4 million patients worldwide with mortality rates approaching 75%. It is thus imperative to study fungal virulence mechanisms, efficacy of antifungal drugs, and host response pathways. While this is commonly done in mammalian models, which are afflicted by ethical and practical concerns, invertebrate models, such as wax moth larvae and nematodes have been introduced over the last two decades. To complement existing invertebrate host models, we developed fifth instar caterpillars of the Tobacco Hornworm moth Manduca sexta as a novel host model. These caterpillars can be maintained at 37°C, are suitable for injections with defined amounts of yeast cells, and are susceptible to the most threatening yeast pathogens, including C. albicans, C. neoformans, C. auris, and C. glabrata. Importantly, fungal burden can be assessed daily throughout the course of infection in a single caterpillar’s feces and hemolymph. Infected caterpillars can be rescued by treatment with antifungal drugs. Notably, these animals are large enough for weight to provide a reliable and reproducible measure of fungal disease and to facilitate host tissue-specific expression analyses. M. sexta caterpillars combine a suite of parameters that make them suitable for the study of fungal virulence.
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Affiliation(s)
- Naomi Lyons
- School of Molecular Cell Biology and Biotechnology, Tel Aviv University , Tel Aviv, Israel.,Department of Biology & Biochemistry, University of Bath , Bath, UK
| | - Isabel Softley
- Department of Biology & Biochemistry, University of Bath , Bath, UK
| | - Andrew Balfour
- Department of Biology & Biochemistry, University of Bath , Bath, UK
| | | | - Heath E O'Brien
- MRC Centre for Neuropsychiatric Genetics & Genomics, Division of Psychological Medicine & Clinical Neurosciences, Cardiff University , Cardiff, UK
| | - Amol C Shetty
- Institute for Genome Sciences, University of Maryland School of Medicine , Baltimore, MD, USA
| | - Vincent M Bruno
- Institute for Genome Sciences, University of Maryland School of Medicine , Baltimore, MD, USA
| | - Stephanie Diezmann
- Department of Biology & Biochemistry, University of Bath , Bath, UK.,School of Cellular and Molecular Medicine, University of Bristol , Bristol, UK
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22
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Abstract
Candida albicans is an opportunistic fungal pathogen and a model organism to study fungal pathogenesis. It exists as a harmless commensal organism and member of the healthy human microbiome, but can cause life-threatening mucosal and systemic infections. A model host to study C. albicans infection and pathogenesis is the nematode Caenorhabditis elegans. C. elegans is frequently used as a model host to study microbial-host interactions because it can be infected by many human pathogens and there are also close morphological resemblances between the intestinal cells of C. elegans and mammals, where C. albicans infections can occur. This article outlines a detailed methodology for exploiting C. elegans as a host to study C. albicans infection, including a C. elegans egg preparation protocol and an agar-based C. elegans killing protocol to monitor fungal virulence. These protocols can additionally be used to study C. albicans genetic mutants in order to further our understanding of the genes involved in pathogenesis and virulence in C. albicans and the mechanisms of host-microbe interactions. © 2020 Wiley Periodicals LLC. Basic Protocol 1: Preparation of Caenorhabditis elegans eggs Support Protocol 1: Freezing and recovering Caenorhabditis elegans Support Protocol 2: Making superfood agar and OP50 plates Basic Protocol 2: Caenorhabditis elegans/Candida albicans agar killing assay Support Protocol 3: Constructing a worm pick.
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Affiliation(s)
- Grace H Kim
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Sierra Rosiana
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | | | - Rebecca S Shapiro
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
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23
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Ye G, Zhang L, Zhou X. Long noncoding RNAs are potentially involved in the degeneration of virulence in an aphid-obligate pathogen, Conidiobolus obscurus (Entomophthoromycotina). Virulence 2021; 12:1705-1716. [PMID: 34167451 PMCID: PMC8237998 DOI: 10.1080/21505594.2021.1938806] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Virulence attenuation frequently occurs in in vitro culturing of pathogenic microbes. In this study, we investigated the total putative long noncoding RNAs (lncRNAs) in an aphid-obligate pathogen, Conidiobolus obscurus, and screened the differentially expressed (DE) lncRNAs and protein-coding genes involved in the virulence decline. The virulence was significantly attenuated after eight subculturing events, in which the median lethal concentration of the conidia ejected from mycelial mats relative to the bamboo aphid, Takecallis taiwanus, increased from 36.1 to 126.1 conidia mm–2, four days after inoculation. In total, 1,252 lncRNAs were identified based on the genome-wide transcriptional analysis. By characterizing their molecular structures and expression patterns, we found that the lncRNAs possessed shorter transcripts, lower expression, and fewer exons than did protein-coding genes in C. obscurus. A total of 410 DE genes of 329 protein-coding genes and 81 lncRNAs were identified. The functional enrichment analysis showed the DE genes were enriched in peptidase activity, protein folding, autophagy, and metabolism. Moreover, target prediction analysis of the 81 lncRNAs revealed 3,111 cis-regulated and 23 trans-regulated mRNAs, while 121 DE lncRNA-mRNA pairs were possibly involved in virulence decline. Moreover, the DE lncRNA-regulated target genes mainly encoded small heat shock proteins, secretory proteins, transporters, autophagy proteins, and other stress response-related proteins. This implies that the decline in virulence regulated by lncRNAs was likely associated with the environmental stress response of C. obscurus. Hence, these findings can provide insights into the lncRNA molecules of Entomophthoromycotina, with regards to virulence regulators of entomopathogens.
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Affiliation(s)
- Guofang Ye
- Forest Protection Department, State Key Laboratory of Subtropical Silviculture, National Joint Local Engineering Laboratory of Biopesticide High-efficient Preparation, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, People's Republic of China
| | - Lvhao Zhang
- Forest Protection Department, State Key Laboratory of Subtropical Silviculture, National Joint Local Engineering Laboratory of Biopesticide High-efficient Preparation, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, People's Republic of China
| | - Xiang Zhou
- Forest Protection Department, State Key Laboratory of Subtropical Silviculture, National Joint Local Engineering Laboratory of Biopesticide High-efficient Preparation, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, People's Republic of China
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24
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Abstract
The requirement of macroautophagic/autophagic machinery for filamentous fungal development and pathogenicity has been recognized, but the underlying effects and mechanisms remain elusive. The insect pathogenic fungus Metarhizium robertsii infects hosts by cuticular penetration through the formation of the infection structure appressoria. Here, we show that autophagic fluxes were highly activated during the appressorial formation of M. robertsii. Genome-wide deletion of the autophagy-related genes and insect bioassays identified 10 of 23 encoded MrATG genes with requirements for topical fungal infection of insect hosts. Besides the defect in forming appressoria on insects (two null mutants), these virulence-reduced mutants were largely impaired in penetrating cellophane membrane and insect cuticles, suggesting their failures in generating proper appressorium turgor. We found that the conidial storage of lipid droplets (LDs) had no obvious difference between strains, but autophagic LD degradation was impaired in different mutants. After induction of cell autophagy by nitrogen starvation, we found that LD entry into vacuoles was unaffected in the selected mutant cells with potential failures in forming autophagosomes. The finding therefore reveals a microlipophagy machinery employed in this fungus and that the direct engulfment of LDs occurs without inhibition by the downstream defective lipolysis. Our data first unveil the activation and contribution of microlipophagy to fungal infection biology. The obtained technique may benefit future detection of microlipophagy in different organisms by examining vacuolar or lysosomal engulfment of LDs in core autophagic gene deletion mutants.
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Affiliation(s)
- Bing Li
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China.,CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shuangxiu Song
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China.,CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xuefei Wei
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China.,CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guirong Tang
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Chengshu Wang
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China.,CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
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25
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F. Q. Smith D, Casadevall A. Fungal immunity and pathogenesis in mammals versus the invertebrate model organism Galleria mellonella. Pathog Dis 2021; 79:ftab013. [PMID: 33544836 PMCID: PMC7981337 DOI: 10.1093/femspd/ftab013] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 02/03/2021] [Indexed: 02/07/2023] Open
Abstract
In recent decades, Galleria mellonella (Lepidoptera: Pyralidae) have emerged as a model system to explore experimental aspects of fungal pathogenesis. The benefits of the G. mellonella model include being faster, cheaper, higher throughput and easier compared with vertebrate models. Additionally, as invertebrates, their use is subject to fewer ethical and regulatory issues. However, for G. mellonella models to provide meaningful insight into fungal pathogenesis, the G. mellonella-fungal interactions must be comparable to mammalian-fungal interactions. Indeed, as discussed in the review, studies suggest that G. mellonella and mammalian immune systems share many similarities, and fungal virulence factors show conserved functions in both hosts. While the moth model has opened novel research areas, many comparisons are superficial and leave large gaps of knowledge that need to be addressed concerning specific mechanisms underlying G. mellonella-fungal interactions. Closing these gaps in understanding will strengthen G. mellonella as a model for fungal virulence in the upcoming years. In this review, we provide comprehensive comparisons between fungal pathogenesis in mammals and G. mellonella from immunological and virulence perspectives. When information on an antifungal immune component is unknown in G. mellonella, we include findings from other well-studied Lepidoptera. We hope that by outlining this information available in related species, we highlight areas of needed research and provide a framework for understanding G. mellonella immunity and fungal interactions.
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Affiliation(s)
- Daniel F. Q. Smith
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Arturo Casadevall
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
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26
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Araújo GRDS, Alves V, Martins-de-Souza PH, Guimarães AJ, Honorato L, Nimrichter L, Takiya CM, Pontes B, Frases S. Dexamethasone and Methylprednisolone Promote Cell Proliferation, Capsule Enlargement, and in vivo Dissemination of C. neoformans. Front Fungal Biol 2021; 2:643537. [PMID: 37744119 PMCID: PMC10512211 DOI: 10.3389/ffunb.2021.643537] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 01/19/2021] [Indexed: 09/26/2023]
Abstract
Cryptococcus neoformans is a fungal pathogen that causes life-threatening infections in immunocompromised individuals, who often have some inflammatory condition and, therefore, end up using glucocorticoids, such as dexamethasone and methylprednisolone. Although the effects of this class of molecules during cryptococcosis have been investigated, their consequences for the biology of C. neoformans is less explored. Here, we studied the effects of dexamethasone and methylprednisolone on the metabolism and on the induction of virulence factors in C. neoformans. Our results showed that both glucocorticoids increased fungal cell proliferation and surface electronegativity but reduced capsule and secreted polysaccharide sizes, as well as capsule compaction, by decreasing the density of polysaccharide fibers. We also tested whether glucocorticoids could affect the fungal virulence in Galleria mellonella and mice. Although the survival rate of Galleria larvae increased, those from mice showed a tendency to decrease, with infected animals dying earlier after glucocorticoid treatments. The pathogenesis of spread of cryptococcosis and the interleukin secretion pattern were also assessed for lungs and brains of infected mice. While increases in the spread of the fungus to lungs were observed after treatment with glucocorticoids, a significant difference in brain was observed only for methylprednisolone, although a trend toward increasing was also observed for dexamethasone. Moreover, increases in both pulmonary and cerebral IL-10 production, reduction of IL-6 production but no changes in IL-4, IL-17, and INF-γ were also observed after glucocorticoid treatments. Finally, histopathological analysis confirmed the increase in number of fungal cells in lung and brain tissues of mice previously subjected to dexamethasone or methylprednisolone treatments. Together, our results provide compelling evidence for the effects of dexamethasone and methylprednisolone on the biology of C. neoformans and may have important implications for future clinical treatments, calling attention to the risks of using these glucocorticoids against cryptococcosis or in immunocompromised individuals.
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Affiliation(s)
- Glauber R. de S. Araújo
- Laboratório de Ultraestrutura Cellular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
- 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 Ultraestrutura Cellular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Pedro H. Martins-de-Souza
- Laboratório de Ultraestrutura Cellular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Allan J. Guimarães
- Laboratório de Bioquímica e Imunologia das Micoses, Depto. de Microbiologia e Parasitologia, Instituto Biomédico, Universidade Federal Fluminense, Niterói, Brazil
| | - Leandro Honorato
- Instituto de Microbiologia Paulo de Góes, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Leonardo Nimrichter
- Instituto de Microbiologia Paulo de Góes, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Christina Maeda Takiya
- Laboratório de Imunopatologia. Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Bruno Pontes
- Instituto de Ciências Biomédicas, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
- Centro Nacional de Biologia Estrutural e Bioimagem (CENABIO), Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Susana Frases
- Laboratório de Ultraestrutura Cellular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
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27
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Cramer RA, Kowalski CH. Is It Time To Kill the Survival Curve? A Case for Disease Progression Factors in Microbial Pathogenesis and Host Defense Research. mBio 2021; 12:e03483-20. [PMID: 33563835 DOI: 10.1128/mBio.03483-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The molecular mechanisms of microbial virulence and host defense are most often studied using animal models and Koch's molecular postulates. A common rationale for these types of experiments is to identify therapeutic targets based on the assumption that microbial or host factors that confer extreme animal model survival phenotypes represent critical virulence and host defense factors. Yet null mutant strains of microbial (or host) factors often yield extreme survival curve phenotypes because they fail to establish an infection. The lack of infection and disease establishment prevents true assessment of the given factor's role(s) in disease progression. Here, we posit that the emphasis on extreme survival curve phenotypes in fungal infectious disease models is leading to missed opportunities to identify new fungal and host factors critical for disease progression. We simply do not yet have a sufficient understanding of fungal virulence and host defense mechanisms throughout the temporal course of an infection. We propose that there is a need to develop new approaches and to revisit tried and true methods to define infection site biology beyond the analysis of survival curve phenotypes. To stimulate these new approaches, we propose the (new) terms "disease initiation factor" and "disease progression factor" to distinguish functional roles at distinct temporal stages of an infection and give us targets to foster new discoveries.
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28
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Dümig M, Binder J, Gaculenko A, Daul F, Winandy L, Hasenberg M, Gunzer M, Fischer R, Künzler M, Krappmann S. The infectious propagules of Aspergillus fumigatus are coated with antimicrobial peptides. Cell Microbiol 2021; 23:e13301. [PMID: 33331054 DOI: 10.1111/cmi.13301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 12/11/2020] [Accepted: 12/13/2020] [Indexed: 11/29/2022]
Abstract
Fungal spores are unique cells that mediate dispersal and survival in the environment. For pathogenic fungi encountering a susceptible host, these specialised structures may serve as infectious particles. The main causative agent of the opportunistic disease aspergillosis, Aspergillus fumigatus, produces asexual spores, the conidia, that become dissipated by air flows or water currents but also serve as propagules to infect a susceptible host. We demonstrate that the defX gene of this mould encodes putative antimicrobial peptides resembling cysteine-stabilised (CS)αβ defensins that are expressed in a specific spatial and temporal manner in the course of asexual spore formation. Localisation studies on strains expressing a fluorescent proxy or tagged defX alleles expose that these antimicrobial peptides are secreted to coat the conidial surface. Deletion mutants reveal that the spore-associated defX gene products delay the growth of Gram-positive Staphylococcus aureus and demonstrate that the defX gene and presumably its encoded spore-associated defensins confer a growth advantage to the fungal opponent over bacterial competitors. These findings have implications with respect to the ecological niche of A. fumigatus that serves as a 'virulence school' for this human pathogenic mould; further relevance is given for the infectious process resulting in aspergillosis, considering competition with the host microbiome or co-infecting microorganisms to break colonisation resistance at host surfaces.
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Affiliation(s)
- Michaela Dümig
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen and Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Jasmin Binder
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen and Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Anastasia Gaculenko
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen and Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Franziska Daul
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen and Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Lex Winandy
- Department of Microbiology, Institute for Applied Biosciences, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Mike Hasenberg
- Imaging Centre Essen (IMCES) - Electron Microscopy Unit, University Hospital and University Duisburg-Essen, Essen, Germany.,Institute for Experimental Immunology and Imaging, University Hospital and University Duisburg-Essen, Essen, Germany
| | - Matthias Gunzer
- Institute for Experimental Immunology and Imaging, University Hospital and University Duisburg-Essen, Essen, Germany
| | - Reinhard Fischer
- Department of Microbiology, Institute for Applied Biosciences, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Markus Künzler
- Department of Biology, Institute of Microbiology, ETH Zürich, Zürich, Switzerland
| | - Sven Krappmann
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen and Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.,Medical Immunology Campus Erlangen, Erlangen, Germany
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29
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Gonçales RA, Ricci-Azevedo R, Vieira VCS, Fernandes FF, Thomaz SMDO, Carvalho A, Vendruscolo PE, Cunha C, Roque-Barreira MC, Rodrigues F. Paracoccin Overexpression in Paracoccidioides brasiliensis Enhances Fungal Virulence by Remodeling Chitin Properties of the Cell Wall. J Infect Dis 2020; 224:164-174. [PMID: 33201217 DOI: 10.1093/infdis/jiaa707] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 11/12/2020] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND The thermodimorphic fungi Paracoccidioides spp. are the etiological agents of paracoccidioidomycosis. Although poorly studied, paracoccin (PCN) from Paracoccidioides brasiliensis has been shown to harbor lectinic, enzymatic, and immunomodulatory properties that affect disease development. METHODS Mutants of P. brasiliensis overexpressing PCN (ov-PCN) were constructed by Agrobacterium tumefaciens-mediated transformation. ov-PCN strains were analyzed and inoculated intranasally or intravenously to mice. Fungal burden, lung pathology, and survival were monitored to evaluate virulence. Electron microscopy was used to evaluate the size of chito-oligomer particles released by ov-PCN or wild-type strains to growth media. RESULTS ov-PCN strains revealed no differences in cell growth and viability, although PCN overexpression favored cell separation, chitin processing that results in the release of smaller chito-oligomer particles, and enhanced virulence. Our data show that PCN triggers a critical effect in the cell wall biogenesis through the chitinase activity resulting from overexpression of PCN. As such, PCN overexpression aggravates the disease caused by P. brasiliensis. CONCLUSIONS Our data are consistent with a model in which PCN modulates the cell wall architecture via its chitinase activity. These findings highlight the potential for exploiting PCN function in future therapeutic approaches.
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Affiliation(s)
- Relber Aguiar Gonçales
- Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto/São Paulo, Brazil.,Life and Health Sciences Research Institute School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Rafael Ricci-Azevedo
- Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto/São Paulo, Brazil
| | - Vanessa C S Vieira
- Life and Health Sciences Research Institute School of Medicine, University of Minho, Braga, Portugal
| | - Fabrício F Fernandes
- Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto/São Paulo, Brazil
| | - Sandra M de O Thomaz
- Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto/São Paulo, Brazil
| | - Agostinho Carvalho
- Life and Health Sciences Research Institute School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Patrícia E Vendruscolo
- Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto/São Paulo, Brazil
| | - Cristina Cunha
- Life and Health Sciences Research Institute School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Maria Cristina Roque-Barreira
- Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto/São Paulo, Brazil
| | - Fernando Rodrigues
- Life and Health Sciences Research Institute School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
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Desmarini D, Lev S, Furkert D, Crossett B, Saiardi A, Kaufman-Francis K, Li C, Sorrell TC, Wilkinson-White L, Matthews J, Fiedler D, Djordjevic JT. IP(7)-SPX Domain Interaction Controls Fungal Virulence by Stabilizing Phosphate Signaling Machinery. mBio 2020; 11. [PMID: 33082258 DOI: 10.1128/mBio.01920-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
In the human-pathogenic fungus Cryptococcus neoformans, the inositol polyphosphate signaling pathway is critical for virulence. We recently demonstrated the key role of the inositol pyrophosphate IP7 (isomer 5-PP-IP5) in driving fungal virulence; however, the mechanism of action remains elusive. Using genetic and biochemical approaches, and mouse infection models, we show that IP7 synthesized by Kcs1 regulates fungal virulence by binding to a conserved lysine surface cluster in the SPX domain of Pho81. Pho81 is the cyclin-dependent kinase (CDK) inhibitor of the phosphate signaling (PHO) pathway. We also provide novel mechanistic insight into the role of IP7 in PHO pathway regulation by demonstrating that IP7 functions as an intermolecular "glue" to stabilize Pho81 association with Pho85/Pho80 and, hence, promote PHO pathway activation and phosphate acquisition. Blocking IP7-Pho81 interaction using site-directed mutagenesis led to a dramatic loss of fungal virulence in a mouse infection model, and the effect was similar to that observed following PHO81 gene deletion, highlighting the key importance of Pho81 in fungal virulence. Furthermore, our findings provide additional evidence of evolutionary divergence in PHO pathway regulation in fungi by demonstrating that IP7 isomers have evolved different roles in PHO pathway control in C. neoformans and nonpathogenic yeast.IMPORTANCE Invasive fungal diseases pose a serious threat to human health globally with >1.5 million deaths occurring annually, 180,000 of which are attributable to the AIDS-related pathogen, Cryptococcus neoformans Here, we demonstrate that interaction of the inositol pyrophosphate, IP7, with the CDK inhibitor protein, Pho81, is instrumental in promoting fungal virulence. IP7-Pho81 interaction stabilizes Pho81 association with other CDK complex components to promote PHO pathway activation and phosphate acquisition. Our data demonstrating that blocking IP7-Pho81 interaction or preventing Pho81 production leads to a dramatic loss in fungal virulence, coupled with Pho81 having no homologue in humans, highlights Pho81 function as a potential target for the development of urgently needed antifungal drugs.
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Correia I, Wilson D, Hube B, Pla J. Characterization of a Candida albicans Mutant Defective in All MAPKs Highlights the Major Role of Hog1 in the MAPK Signaling Network. J Fungi (Basel) 2020; 6:jof6040230. [PMID: 33080787 PMCID: PMC7711971 DOI: 10.3390/jof6040230] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 10/12/2020] [Accepted: 10/14/2020] [Indexed: 12/16/2022] Open
Abstract
The success of Candida albicans as a pathogen relies on its ability to adapt and proliferate in different environmental niches. Pathways regulated by mitogen-activated protein kinases (MAPKs) are involved in sensing environmental conditions and developing an accurate adaptive response. Given the frequent cooperative roles of these routes in cellular functions, we have generated mutants defective in all combinations of the four described MAPKs in C. albicans and characterized its phenotype regarding sensitiveness to specific drugs, morphogenesis and interaction with host immune cells. We demonstrate that all MAPKs are dispensable in this yeast as a mutant defective in Cek1, Cek2, Mkc1 and Hog1 is viable although highly sensitive to oxidative and osmotic stress, displaying a specific pattern of sensitivity to antifungals. By comparing its phenotype with single, double and triple combinations of MAPK-deletion mutants we were able to unveil a Cek1-independent mechanism for Hog1 resistance to Congo red, and confirm the predominant effect of Hog1 on oxidative and osmotic adaptation. The quadruple mutant produces filaments under non-inducing conditions, but is unable to develop chlamydospores. Furthermore, cek1 cek2 mkc1 hog1 cells switch to the opaque state at high frequency, which is blocked by the ectopic expression of HOG1 suggesting a role of this kinase for phenotypic switching.
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Affiliation(s)
- Inês Correia
- iBiMED-Institute of Biomedicine, Department of Medical Sciences, University of Aveiro, Agra do Crasto, 3810-193 Aveiro, Portugal
- Correspondence: (I.C.); (J.P.); Tel.: +351-234-370-213 (I.C.); +34-913-941-617 (J.P.)
| | - Duncan Wilson
- Medical Research Council Centre for Medical Mycology, School of Biosciences, University of Exeter, Exeter EX4 4QD, UK;
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology-Hans-Knoell-Institute, Beutenbergstraße 11A, 07745 Jena, Germany;
- Institute of Microbiology, Friedrich Schiller University, Neugasse 25, 07743 Jena, Germany
| | - Jesús Pla
- Departamento de Microbiología y Parasitología-IRYCIS, Facultad de Farmacia, Universidad Complutense de Madrid, Avda. Ramón y Cajal s/n, 28040 Madrid, Spain
- Correspondence: (I.C.); (J.P.); Tel.: +351-234-370-213 (I.C.); +34-913-941-617 (J.P.)
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Lopes L, Bitencourt TA, Lang EAS, Sanches PR, Peres NTA, Rossi A, Martinez-Rossi NM. Genes coding for LysM domains in the dermatophyte Trichophyton rubrum: A transcription analysis. Med Mycol 2020; 58:372-379. [PMID: 31226713 DOI: 10.1093/mmy/myz068] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 05/28/2019] [Accepted: 05/31/2019] [Indexed: 01/23/2023] Open
Abstract
The filamentous fungus Trichophyton rubrum is a pathogen that causes superficial mycoses in humans, predominantly in keratinized tissues. The occurrence of dermatophytoses has increased in the last decades, mainly in immunocompromised patients, warranting research on the mechanisms involved in dermatophyte virulence. The genomes of dermatophytes are known to be enriched in genes coding for proteins containing the LysM domain, a carbohydrate-binding module, indicating the possible involvement of these genes in virulence. Although the LysM domains have already been described in other fungi, their biological functions in dermatophytes are unknown. Here we assessed the transcription of genes encoding proteins containing the LysM domains in T. rubrum grown on different substrates using quantitative real-time polymerase chain reaction. Some of these genes showed changes in transcription levels when T. rubrum was grown on keratin. In silico analyses suggest that some of these proteins share features, namely, they are anchored in the plasma membrane and contain the catalytic domain chitinase II and signal peptide domains. Here we show a detailed study of genes encoding the proteins with LysM-containing domains in T. rubrum, aiming to contribute to the understanding of their functions in dermatophytes.
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Affiliation(s)
- Lúcia Lopes
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Tamires A Bitencourt
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Elza A S Lang
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Pablo R Sanches
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Nalu T A Peres
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
- Department of Biology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Antonio Rossi
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Nilce M Martinez-Rossi
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
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Scott J, Sueiro-Olivares M, Thornton BP, Owens RA, Muhamadali H, Fortune-Grant R, Thomson D, Thomas R, Hollywood K, Doyle S, Goodacre R, Tabernero L, Bignell E, Amich J. Targeting Methionine Synthase in a Fungal Pathogen Causes a Metabolic Imbalance That Impacts Cell Energetics, Growth, and Virulence. mBio 2020; 11:e01985-20. [PMID: 33051366 DOI: 10.1128/mBio.01985-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Fungal pathogens are responsible for millions of life-threatening infections on an annual basis worldwide. The current repertoire of antifungal drugs is very limited and, worryingly, resistance has emerged and already become a serious threat to our capacity to treat fungal diseases. The first step to develop new drugs is often to identify molecular targets in the pathogen whose inhibition during infection can prevent its growth. However, the current models are not suitable to validate targets in established infections. Here, we have characterized the promising antifungal target methionine synthase in great detail, using the prominent fungal pathogen Aspergillus fumigatus as a model. We have uncovered the underlying reason for its essentiality and confirmed its druggability. Furthermore, we have optimized the use of a genetic system to show a beneficial effect of targeting methionine synthase in established infections. Therefore, we believe that antifungal drugs to target methionine synthase should be pursued and additionally, we provide a model that permits gaining information about the validity of antifungal targets in established infections. There is an urgent need to develop novel antifungals to tackle the threat fungal pathogens pose to human health. Here, we have performed a comprehensive characterization and validation of the promising target methionine synthase (MetH). We show that in Aspergillus fumigatus the absence of this enzymatic activity triggers a metabolic imbalance that causes a reduction in intracellular ATP, which prevents fungal growth even in the presence of methionine. Interestingly, growth can be recovered in the presence of certain metabolites, which shows that metH is a conditionally essential gene and consequently should be targeted in established infections for a more comprehensive validation. Accordingly, we have validated the use of the tetOFF genetic model in fungal research and improved its performance in vivo to achieve initial validation of targets in models of established infection. We show that repression of metH in growing hyphae halts growth in vitro, which translates into a beneficial effect when targeting established infections using this model in vivo. Finally, a structure-based virtual screening of methionine synthases reveals key differences between the human and fungal structures and unravels features in the fungal enzyme that can guide the design of novel specific inhibitors. Therefore, methionine synthase is a valuable target for the development of new antifungals.
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Ruben S, Garbe E, Mogavero S, Albrecht-Eckardt D, Hellwig D, Häder A, Krüger T, Gerth K, Jacobsen ID, Elshafee O, Brunke S, Hünniger K, Kniemeyer O, Brakhage AA, Morschhäuser J, Hube B, Vylkova S, Kurzai O, Martin R. Ahr1 and Tup1 Contribute to the Transcriptional Control of Virulence-Associated Genes in Candida albicans. mBio 2020; 11:e00206-20. [PMID: 32345638 DOI: 10.1128/mBio.00206-20] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Candida albicans is a major human fungal pathogen and the leading cause of systemic Candida infections. In recent years, Als3 and Ece1 were identified as important factors for fungal virulence. Transcription of both corresponding genes is closely associated with hyphal growth. Here, we describe how Tup1, normally a global repressor of gene expression as well as of filamentation, and the transcription factor Ahr1 contribute to full expression of ALS3 and ECE1 in C. albicans hyphae. Both regulators are required for high mRNA amounts of the two genes to ensure functional relevant protein synthesis and localization. These observations identified a new aspect of regulation in the complex transcriptional control of virulence-associated genes in C. albicans. The capacity of Candida albicans to reversibly change its morphology between yeast and filamentous stages is crucial for its virulence. Formation of hyphae correlates with the upregulation of genes ALS3 and ECE1, which are involved in pathogenicity processes such as invasion, iron acquisition, and host cell damage. The global repressor Tup1 and its cofactor Nrg1 are considered to be the main antagonists of hyphal development in C. albicans. However, our experiments revealed that Tup1, but not Nrg1, was required for full expression of ALS3 and ECE1. In contrast to NRG1, overexpression of TUP1 was found to inhibit neither filamentous growth nor transcription of ALS3 and ECE1. In addition, we identified the transcription factor Ahr1 as being required for full expression of both genes. A hyperactive version of Ahr1 bound directly to the promoters of ALS3 and ECE1 and induced their transcription even in the absence of environmental stimuli. This regulation worked even in the absence of the crucial hyphal growth regulators Cph1 and Efg1 but was dependent on the presence of Tup1. Overall, our results show that Ahr1 and Tup1 are key contributors in the complex regulation of virulence-associated genes in the different C. albicans morphologies.
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Souza ACO, Al Abdallah Q, DeJarnette K, Martin-Vicente A, Nywening AV, DeJarnette C, Sansevere EA, Ge W, Palmer GE, Fortwendel JR. Differential requirements of protein geranylgeranylation for the virulence of human pathogenic fungi. Virulence 2020; 10:511-526. [PMID: 31131706 PMCID: PMC6550545 DOI: 10.1080/21505594.2019.1620063] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Protein prenylation is a crucial post-translational modification largely mediated by two heterodimeric enzyme complexes, farnesyltransferase and geranylgeranyltransferase type-I (GGTase-I), each composed of a shared α-subunit and a unique β-subunit. GGTase-I enzymes are validated drug targets that contribute to virulence in Cryptococcus neoformans and to the yeast-to-hyphal transition in Candida albicans. Therefore, we sought to investigate the importance of the α-subunit, RamB, and the β-subunit, Cdc43, of the A. fumigatus GGTase-I complex to hyphal growth and virulence. Deletion of cdc43 resulted in impaired hyphal morphogenesis and thermo-sensitivity, which was exacerbated during growth in rich media. The Δcdc43 mutant also displayed hypersensitivity to cell wall stress agents and to cell wall synthesis inhibitors, suggesting alterations of cell wall biosynthesis or stress signaling. In support of this, analyses of cell wall content revealed decreased amounts of β-glucan in the Δcdc43 strain. Despite strong in vitro phenotypes, the Δcdc43 mutant was fully virulent in two models of murine invasive aspergillosis, similar to the control strain. We further found that a strain expressing the α-subunit gene, ramB, from a tetracycline-inducible promoter was inviable under non-inducing in vitro growth conditions and was virtually avirulent in both mouse models. Lastly, virulence studies using C. albicans strains with tetracycline-repressible RAM2 or CDC43 expression revealed reduced pathogenicity associated with downregulation of either gene in a murine model of disseminated infection. Together, these findings indicate a differential requirement for protein geranylgeranylation for fungal virulence, and further inform the selection of specific prenyltransferases as promising antifungal drug targets for each pathogen.
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Affiliation(s)
- Ana Camila Oliveira Souza
- a Department of Clinical Pharmacy and Translational Science , College of Pharmacy, University of Tennessee Health Science Center , Memphis , TN , USA
| | - Qusai Al Abdallah
- a Department of Clinical Pharmacy and Translational Science , College of Pharmacy, University of Tennessee Health Science Center , Memphis , TN , USA
| | - Kaci DeJarnette
- a Department of Clinical Pharmacy and Translational Science , College of Pharmacy, University of Tennessee Health Science Center , Memphis , TN , USA
| | - Adela Martin-Vicente
- a Department of Clinical Pharmacy and Translational Science , College of Pharmacy, University of Tennessee Health Science Center , Memphis , TN , USA
| | - Ashley V Nywening
- b Department of Molecular Immunology and Biochemistry , College of Graduate Health Sciences, University of Tennessee Health Science Center , Memphis , TN , USA
| | - Christian DeJarnette
- b Department of Molecular Immunology and Biochemistry , College of Graduate Health Sciences, University of Tennessee Health Science Center , Memphis , TN , USA
| | - Emily A Sansevere
- a Department of Clinical Pharmacy and Translational Science , College of Pharmacy, University of Tennessee Health Science Center , Memphis , TN , USA
| | - Wenbo Ge
- a Department of Clinical Pharmacy and Translational Science , College of Pharmacy, University of Tennessee Health Science Center , Memphis , TN , USA
| | - Glen E Palmer
- a Department of Clinical Pharmacy and Translational Science , College of Pharmacy, University of Tennessee Health Science Center , Memphis , TN , USA
| | - Jarrod R Fortwendel
- a Department of Clinical Pharmacy and Translational Science , College of Pharmacy, University of Tennessee Health Science Center , Memphis , TN , USA
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Santos Rezende J, Zivanovic M, Costa de Novaes MI, Chen Z. The AVR4 effector is involved in cercosporin biosynthesis and likely affects the virulence of Cercospora cf. flagellaris on soybean. Mol Plant Pathol 2020; 21:53-65. [PMID: 31642594 PMCID: PMC6913201 DOI: 10.1111/mpp.12879] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
One of the most devastating fungal diseases of soybean in the southern USA is Cercospora leaf blight (CLB), which is caused mainly by Cercospora cf. flagellaris. Recent studies found that the fungal effector AVR4, originally identified in Cladosporium fulvum as a chitin-binding protein, is highly conserved among other Cercospora species. We wanted to determine whether it is present in C. cf. flagellaris and, if so, whether it plays a role in the pathogen infection of soybean. We cloned the Avr4 gene and created C. cf. flagellaris ∆avr4 mutants, which produced little cercosporin and significantly reduced expression of cercosporin biosynthesis genes. The ∆avr4 mutants were also more sensitive to chitinase and showed reduced virulence on soybean compared to the wild-type. The observed reduced virulence of C. cf. flagellaris ∆avr4 mutants on detached soybean leaves is likely due to reduced cercosporin biosynthesis. The phenotypes of reduced cercosporin production and cercosporin pathway gene expression, similar to those of the ∆avr4 mutants, were reproduced when wild-type C. cf. flagellaris was treated with double-stranded RNA targeting Avr4 in vitro. These two independent approaches demonstrated for the first time the direct involvement of AVR4 in the biosynthesis of cercosporin.
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Affiliation(s)
- Josielle Santos Rezende
- Department of Plant Pathology and Crop PhysiologyLouisiana State University Agricultural CenterBaton RougeLA70803USA
| | - Marija Zivanovic
- Department of Plant Pathology and Crop PhysiologyLouisiana State University Agricultural CenterBaton RougeLA70803USA
| | - Maria Izabel Costa de Novaes
- Department of Plant Pathology and Crop PhysiologyLouisiana State University Agricultural CenterBaton RougeLA70803USA
| | - Zhi‐Yuan Chen
- Department of Plant Pathology and Crop PhysiologyLouisiana State University Agricultural CenterBaton RougeLA70803USA
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Martho KF, Brustolini OJB, Vasconcelos AT, Vallim MA, Pascon RC. The Glycerol Phosphatase Gpp2: A Link to Osmotic Stress, Sulfur Assimilation and Virulence in Cryptococcus neoformans. Front Microbiol 2019; 10:2728. [PMID: 31849880 PMCID: PMC6901960 DOI: 10.3389/fmicb.2019.02728] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 11/08/2019] [Indexed: 12/13/2022] Open
Abstract
Cryptococcus neoformans is an opportunist fungal pathogen that causes meningoencephalitis in immunocompromised patients. During infection, this basidiomycete yeast has to adapt to several adverse conditions, especially nutrient availability. The interruption on various amino acid biosynthetic pathways and on amino acid uptake causes reduced viability, inability to cope with various stresses, failure in virulence factors expression and avirulence in animal model of infection. The sulfur amino acid biosynthesis and uptake is an important feature for pathogen survival in vivo and in vitro. Our previous work demonstrates that C. neoformans Cys3 BZip transcription factor controls the gene expression in several steps of the sulfur assimilation and sulfur amino acid biosynthesis. Also, we have shown that Gpp2 phosphatase modulates Cys3 activity. In Saccharomyces cerevisiae Gpp2 is induced in response to hyper osmotic or oxidative stress and during diauxic shift. In this work, we will show that, in C. neoformans, Gpp2 is required to respond to stresses, mainly osmotic stress; also its transcription is induced during exposure to NaCl. Global transcriptional profile of gpp2Δ by RNAseq shows that CYS3 and other genes in the sulfur assimilation pathway are up regulated, which is consistent with our previous report, in which Gpp2 acts by avoiding Cys3 accumulation and nuclear localization. In addition, several transporters genes, especially amino acid permeases and oxidative stress genes are induced in the gpp2Δ strain; on the contrary, genes involved in glucose and tricarboxylic acid metabolism are down regulated. gpp2Δ strain fails to express virulence factors, as melanin, phospholipase, urease and has virulence attenuation in Galleria mellonella. Our data suggest that Gpp2 is an important factor for general pathogen adaptation to various stresses and also to the host, and perhaps it could be an interesting target for therapeutic use.
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Affiliation(s)
- Kevin Felipe Martho
- Department of Biological Sciences, Campus Diadema, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Otávio J B Brustolini
- Laboratório Nacional de Computação Científica - LNCC, Labinfo - Laboratório de Bioinformática, Petrópolis, Brazil
| | - Ana Tereza Vasconcelos
- Laboratório Nacional de Computação Científica - LNCC, Labinfo - Laboratório de Bioinformática, Petrópolis, Brazil
| | - Marcelo A Vallim
- Department of Biological Sciences, Campus Diadema, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Renata C Pascon
- Department of Biological Sciences, Campus Diadema, Universidade Federal de São Paulo, São Paulo, Brazil
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Bui DC, Kim JE, Shin J, Lim JY, Choi GJ, Lee YW, Seo JA, Son H. ARS2 Plays Diverse Roles in DNA Damage Response, Fungal Development, and Pathogenesis in the Plant Pathogenic Fungus Fusarium graminearum. Front Microbiol 2019; 10:2326. [PMID: 31681199 PMCID: PMC6803386 DOI: 10.3389/fmicb.2019.02326] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 09/24/2019] [Indexed: 11/13/2022] Open
Abstract
Arsenite-resistance protein 2 (Ars2) is an important nuclear protein involved in various RNA metabolisms in animals and plants, but no Ars2 ortholog has been studied in filamentous fungi. Although it is an essential gene in most model eukaryotes, FgARS2 null mutants were viable in the plant pathogenic fungus Fusarium graminearum. The deletion of FgARS2 resulted in pleiotropic defects in various fungal developmental processes. Fgars2 mutants were irregular in nuclear division, and conidial germination was significantly retarded, causing the fungus to manifest its hypersensitive phenotypes under DNA damage stress. While FgARS2 deletion caused abnormal morphologies of ascospores and defective ascospore discharge, our data revealed that FgARS2 was not closely involved in small-non-coding RNA production in F. graminearum. The dominant nuclear localization of FgArs2-green fluorescent proteins (GFP) and abnormal nuclear division in FgARS2 deletion mutant implicated that FgArs2 functions in the nucleus. Intriguingly, we found that FgArs2 established a robust physical interaction with the cap binding complex (CBC) to form a tertiary complex CBC-Ars2 (CBCA), and disruption of any CBCA complex subunit drastically attenuated the virulence of F. graminearum. The results of the study indicate that Ars2 regulates fungal development, stress response, and pathogenesis via interaction with CBC in F. graminearum and provide a novel insight into understanding of the biological functions of Ars2 in filamentous fungi.
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Affiliation(s)
- Duc-Cuong Bui
- Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea.,School of Systems Biomedical Science, Soongsil University, Seoul, South Korea
| | - Jung-Eun Kim
- Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
| | - Jiyoung Shin
- Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
| | - Jae Yun Lim
- School of Systems Biomedical Science, Soongsil University, Seoul, South Korea
| | - Gyung Ja Choi
- Therapeutic & Biotechnology Division, Center for Eco-Friendly New Materials, Korea Research Institute of Chemical Technology, Daejeon, South Korea
| | - Yin-Won Lee
- Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
| | - Jeong-Ah Seo
- School of Systems Biomedical Science, Soongsil University, Seoul, South Korea
| | - Hokyoung Son
- Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
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Abstract
Jorge Amich studies several aspects of sulfur and nitrogen metabolism in Aspergillus fumigatus, with the ultimate aim of identifying targets for the development of novel antifungals. In this mSphere of Influence article, he reflects on how “Sub-Telomere Directed Gene Expression during Initiation of Invasive Aspergillosis” (A. McDonagh, N. D. Fedorova, J. Crabtree, Y. Yu, S. Kim, et al., PLoS Pathog 4:e1000154, 2008, https://doi.org/10.1371/journal.ppat.1000154) impacted his thinking about in vivo metabolism and how to investigate it. Jorge Amich studies several aspects of sulfur and nitrogen metabolism in Aspergillus fumigatus, with the ultimate aim of identifying targets for the development of novel antifungals. In this mSphere of Influence article, he reflects on how “Sub-Telomere Directed Gene Expression during Initiation of Invasive Aspergillosis” (A. McDonagh, N. D. Fedorova, J. Crabtree, Y. Yu, S. Kim, et al., PLoS Pathog 4:e1000154, 2008, https://doi.org/10.1371/journal.ppat.1000154) impacted his thinking about in vivo metabolism and how to investigate it.
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de S Araújo GR, Viana NB, Pontes B, Frases S. Rheological properties of cryptococcal polysaccharide change with fiber size, antibody binding and temperature. Future Microbiol 2019; 14:867-884. [PMID: 31340660 DOI: 10.2217/fmb-2018-0320] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Aim: Cryptococcus neoformans is the major agent of cryptococcosis. The main virulence factor is the polysaccharide (PS) capsule. Changes in cryptococcal PS properties have been poorly elucidated. Materials & methods: We analyzed the mechanical properties of secreted PS and intact capsules, using dynamic light scattering and optical tweezers. Results: Storage and loss moduli showed that secreted PS behaves as a viscoelastic liquid, while capsular PS behaves as a viscoelastic solid. The secreted PS remains as a viscoelastic fluid at different temperatures with thermal hysteresis after 85°C. Antibody binding altered the viscoelastic behavior of both secreted and capsular PS. Conclusion: Deciphering the mechanical aspects of these structures could reveal features that may have consequences in novel therapies against cryptococcosis.
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Affiliation(s)
- Glauber R de S Araújo
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Nathan B Viana
- Laboratório de Pinças Óticas (LPO-COPEA), Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.,Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Bruno Pontes
- Laboratório de Pinças Óticas (LPO-COPEA), Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Susana Frases
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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Fang A, Gao H, Zhang N, Zheng X, Qiu S, Li Y, Zhou S, Cui F, Sun W. A Novel Effector Gene SCRE2 Contributes to Full Virulence of Ustilaginoidea virens to Rice. Front Microbiol 2019; 10:845. [PMID: 31105658 PMCID: PMC6492501 DOI: 10.3389/fmicb.2019.00845] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 04/02/2019] [Indexed: 12/13/2022] Open
Abstract
Ustilaginoidea virens, the causal agent of rice false smut (RFS), has become one of the most devastating rice pathogens worldwide. As a group of essential virulence factors, the effectors in the filamentous fungus might play central roles in the interaction between plants and pathogens. However, little is known about the roles of individual effectors in U. virens virulence. In this study, we identified and characterized a small secreted cysteine-rich effector, SCRE2, in U. virens. SCRE2 was first confirmed as an effector through yeast secretion, protein localization and translocation assays, as well as its expression pattern during U. virens infection. Transient expression of SCRE2 in Nicotiana benthamiana suppressed necrosis-like defense symptoms triggered by the mammalian BAX and oomycete elicitin INF1 proteins. The ability of SCRE2 to inhibit immunity-associated responses in N. benthamiana, including elicitor-triggered cell death and oxidative burst, is further defined to a small peptide region SCRE268-85 through expressing a series of truncated proteins. Convincingly, ectopic expression of SCRE2 in the transgenic rice cells significantly inhibited pathogen-associated molecular pattern-triggered immunity including flg22- and chitin-induced defense gene expression and oxidative burst. Furthermore, the scre2 knockout mutant generated by the CRISPR/Cas9 system greatly attenuated in U. virens virulence to rice. Collectively, this study indicates that the effector SCRE2 is able to inhibit plant immunity and is required for full virulence of U. virens.
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Affiliation(s)
- Anfei Fang
- The Ministry of Agriculture Key Laboratory of Pest Monitoring and Green Management, and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Plant Protection, China Agricultural University, Beijing, China.,College of Plant Protection, Southwest University, Chongqing, China
| | - Han Gao
- The Ministry of Agriculture Key Laboratory of Pest Monitoring and Green Management, and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Plant Protection, China Agricultural University, Beijing, China
| | - Nan Zhang
- The Ministry of Agriculture Key Laboratory of Pest Monitoring and Green Management, and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Plant Protection, China Agricultural University, Beijing, China
| | - Xinhang Zheng
- The Ministry of Agriculture Key Laboratory of Pest Monitoring and Green Management, and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Plant Protection, China Agricultural University, Beijing, China
| | - Shanshan Qiu
- The Ministry of Agriculture Key Laboratory of Pest Monitoring and Green Management, and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Plant Protection, China Agricultural University, Beijing, China
| | - Yuejiao Li
- The Ministry of Agriculture Key Laboratory of Pest Monitoring and Green Management, and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Plant Protection, China Agricultural University, Beijing, China
| | - Shuang Zhou
- The Ministry of Agriculture Key Laboratory of Pest Monitoring and Green Management, and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Plant Protection, China Agricultural University, Beijing, China
| | - Fuhao Cui
- The Ministry of Agriculture Key Laboratory of Pest Monitoring and Green Management, and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Plant Protection, China Agricultural University, Beijing, China
| | - Wenxian Sun
- The Ministry of Agriculture Key Laboratory of Pest Monitoring and Green Management, and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Plant Protection, China Agricultural University, Beijing, China.,College of Plant Protection, Jilin Agricultural University, Changchun, China
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Rodríguez-Romero J, Marconi M, Ortega-Campayo V, Demuez M, Wilkinson MD, Sesma A. Virulence- and signaling-associated genes display a preference for long 3'UTRs during rice infection and metabolic stress in the rice blast fungus. New Phytol 2019; 221:399-414. [PMID: 30169888 DOI: 10.1111/nph.15405] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 07/10/2018] [Indexed: 06/08/2023]
Abstract
Generation of mRNA isoforms by alternative polyadenylation (APA) and their involvement in regulation of fungal cellular processes, including virulence, remains elusive. Here, we investigated genome-wide polyadenylation site (PAS) selection in the rice blast fungus to understand how APA regulates pathogenicity. More than half of Magnaporthe oryzae transcripts undergo APA and show novel motifs in their PAS region. Transcripts with shorter 3'UTRs are more stable and abundant in polysomal fractions, suggesting they are being translated more efficiently. Importantly, rice colonization increases the use of distal PASs of pathogenicity genes, especially those participating in signalling pathways like 14-3-3B, whose long 3'UTR is required for infection. Cleavage factor I (CFI) Rbp35 regulates expression and distal PAS selection of virulence and signalling-associated genes, tRNAs and transposable elements, pointing its potential to drive genomic rearrangements and pathogen evolution. We propose a noncanonical PAS selection mechanism for Rbp35 that recognizes UGUAH, unlike humans, without CFI25. Our results showed that APA controls turnover and translation of transcripts involved in fungal growth and environmental adaptation. Furthermore, these data provide useful information for enhancing genome annotations and for cross-species comparisons of PASs and PAS usage within the fungal kingdom and the tree of life.
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Affiliation(s)
- Julio Rodríguez-Romero
- Centre for Plant Biotechnology and Genomics (CBGP UPM-INIA), Universidad Politécnica de Madrid (UPM) & Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Campus de Montegancedo, 28223 Pozuelo de Alarcón, Madrid, Spain
- Departamento de Biotecnología y Biología Vegetal, UPM, Campus Ciudad Universitaria, 28040, Madrid, Spain
| | - Marco Marconi
- Centre for Plant Biotechnology and Genomics (CBGP UPM-INIA), Universidad Politécnica de Madrid (UPM) & Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Campus de Montegancedo, 28223 Pozuelo de Alarcón, Madrid, Spain
- Departamento de Biotecnología y Biología Vegetal, UPM, Campus Ciudad Universitaria, 28040, Madrid, Spain
| | - Víctor Ortega-Campayo
- Centre for Plant Biotechnology and Genomics (CBGP UPM-INIA), Universidad Politécnica de Madrid (UPM) & Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Campus de Montegancedo, 28223 Pozuelo de Alarcón, Madrid, Spain
- Departamento de Biotecnología y Biología Vegetal, UPM, Campus Ciudad Universitaria, 28040, Madrid, Spain
| | - Marie Demuez
- Centre for Plant Biotechnology and Genomics (CBGP UPM-INIA), Universidad Politécnica de Madrid (UPM) & Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Campus de Montegancedo, 28223 Pozuelo de Alarcón, Madrid, Spain
- Departamento de Biotecnología y Biología Vegetal, UPM, Campus Ciudad Universitaria, 28040, Madrid, Spain
| | - Mark D Wilkinson
- Centre for Plant Biotechnology and Genomics (CBGP UPM-INIA), Universidad Politécnica de Madrid (UPM) & Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Campus de Montegancedo, 28223 Pozuelo de Alarcón, Madrid, Spain
- Departamento de Biotecnología y Biología Vegetal, UPM, Campus Ciudad Universitaria, 28040, Madrid, Spain
| | - Ane Sesma
- Centre for Plant Biotechnology and Genomics (CBGP UPM-INIA), Universidad Politécnica de Madrid (UPM) & Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Campus de Montegancedo, 28223 Pozuelo de Alarcón, Madrid, Spain
- Departamento de Biotecnología y Biología Vegetal, UPM, Campus Ciudad Universitaria, 28040, Madrid, Spain
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Upadhya R, Baker LG, Lam WC, Specht CA, Donlin MJ, Lodge JK. Cryptococcus neoformans Cda1 and Its Chitin Deacetylase Activity Are Required for Fungal Pathogenesis. mBio 2018; 9:e02087-18. [PMID: 30459196 DOI: 10.1128/mBio.02087-18] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Cryptococcus neoformans is unique among fungal pathogens that cause disease in a mammalian host, as it secretes a polysaccharide capsule that hinders recognition by the host to facilitate its survival and proliferation. Even though it causes serious infections in immunocompromised hosts, reports of infection in hosts that are immunocompetent are on the rise. The cell wall of a fungal pathogen, its synthesis, composition, and pathways of remodelling are attractive therapeutic targets for the development of fungicides. Chitosan, a polysaccharide in the cell wall of C. neoformans is one such target, as it is critical for pathogenesis and absent in the host. The results we present shed light on the importance of one of the chitin deacetylases that synthesize chitosan during infection and further implicates chitosan as being a critical factor for the pathogenesis of C. neoformans. Chitin is an essential component of the cell wall of Cryptococcus neoformans conferring structural rigidity and integrity under diverse environmental conditions. Chitin deacetylase genes encode the enyzmes (chitin deacetylases [Cdas]) that deacetylate chitin, converting it to chitosan. The functional role of chitosan in the fungal cell wall is not well defined, but it is an important virulence determinant of C. neoformans. Mutant strains deficient in chitosan are completely avirulent in a mouse pulmonary infection model. C. neoformans carries genes that encode three Cdas (Cda1, Cda2, and Cda3) that appear to be functionally redundant in cells grown under vegetative conditions. Here we report that C. neoformans Cda1 is the principal Cda responsible for fungal pathogenesis. Point mutations were introduced in the active site of Cda1 to generate strains in which the enzyme activity of Cda1 was abolished without perturbing either its stability or localization. When used to infect CBA/J mice, Cda1 mutant strains produced less chitosan and were attenuated for virulence. We further demonstrate that C. neoformans Cda genes are transcribed differently during a murine infection from what has been measured in vitro.
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Wang Y, Deng C, Tian L, Xiong D, Tian C, Klosterman SJ. The Transcription Factor VdHapX Controls Iron Homeostasis and Is Crucial for Virulence in the Vascular Pathogen Verticillium dahliae. mSphere 2018; 3:e00400-18. [PMID: 30185514 PMCID: PMC6126142 DOI: 10.1128/msphere.00400-18] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Accepted: 08/14/2018] [Indexed: 11/20/2022] Open
Abstract
Iron homeostasis is essential for full virulence and viability in many pathogenic fungi. Here, we showed that the bZip transcription factor VdHapX functions as a key regulator of iron homeostasis for adaptation to iron-depleted and iron-excess conditions and is required for full virulence in the vascular wilt fungus, Verticillium dahliae Deletion of VdHapX impaired mycelial growth and conidiation under both iron starvation and iron sufficiency. Furthermore, disruption of VdHapX led to decreased formation of the long-lived survival structures of V. dahliae, known as microsclerotia. Expression of genes involved in iron utilization pathways and siderophore biosynthesis was misregulated in the ΔVdHapX strain under the iron-depleted condition. Additionally, the ΔVdHapX strain exhibited increased sensitivity to high iron concentrations and H2O2, indicating that VdHapX also contributes to iron or H2O2 detoxification. The ΔVdHapX strain showed a strong reduction in virulence on smoke tree seedlings (Cotinus coggygria) and was delayed in its ability to penetrate plant epidermal tissue.IMPORTANCE This study demonstrated that VdHapX is a conserved protein that mediates adaptation to iron starvation and excesses, affects microsclerotium formation, and is crucial for virulence of V. dahliae.
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Affiliation(s)
- Yonglin Wang
- Beijing Key Laboratory for Forest Pest Control, College of Forestry, Beijing Forestry University, Beijing, China
| | - Chenglin Deng
- Beijing Key Laboratory for Forest Pest Control, College of Forestry, Beijing Forestry University, Beijing, China
| | - Longyan Tian
- Beijing Key Laboratory for Forest Pest Control, College of Forestry, Beijing Forestry University, Beijing, China
| | - Dianguang Xiong
- Beijing Key Laboratory for Forest Pest Control, College of Forestry, Beijing Forestry University, Beijing, China
| | - Chengming Tian
- Beijing Key Laboratory for Forest Pest Control, College of Forestry, Beijing Forestry University, Beijing, China
| | - Steven J Klosterman
- Agricultural Research Service, United States Department of Agriculture, Salinas, California, USA
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Gu Q, Ji T, Sun X, Huang H, Zhang H, Lu X, Wu L, Huo R, Wu H, Gao X. Histone H3 lysine 9 methyltransferase FvDim5 regulates fungal development, pathogenicity and osmotic stress responses in Fusarium verticillioides. FEMS Microbiol Lett 2018; 364:4094912. [PMID: 28957455 DOI: 10.1093/femsle/fnx184] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Accepted: 08/23/2017] [Indexed: 12/30/2022] Open
Abstract
Histone methylation plays important biological roles in eukaryotic cells. Methylation of lysine 9 at histone H3 (H3K9me) is critical for regulating chromatin structure and gene transcription. Dim5 is a lysine histone methyltransferase (KHMTase) enzyme, which is responsible for the methylation of H3K9 in eukaryotes. In the current study, we identified a single ortholog of Neurospora crassa Dim5 in Fusarium verticillioides. In this study, we report that FvDim5 regulates the trimethylation of H3K9 (H3K9me3). The FvDIM5 deletion mutant (ΔFvDim5) showed significant defects in conidiation, perithecium production and fungal virulence. Unexpectedly, we found that deletion of FvDIM5 resulted in increased tolerance to osmotic stresses and upregulated FvHog1 phosphorylation. These results indicate the importance of FvDim5 for the regulation of fungal development, pathogenicity and osmotic stress responses in F. verticillioides.
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Affiliation(s)
- Qin Gu
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Education, Nanjing 210095, China
| | - Tiantian Ji
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Education, Nanjing 210095, China
| | - Xiao Sun
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Education, Nanjing 210095, China
| | - Hai Huang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Education, Nanjing 210095, China
| | - Hao Zhang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Education, Nanjing 210095, China
| | - Xi Lu
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Education, Nanjing 210095, China
| | - Liming Wu
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Education, Nanjing 210095, China
| | - Rong Huo
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Education, Nanjing 210095, China
| | - Huijun Wu
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Education, Nanjing 210095, China
| | - Xuewen Gao
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Education, Nanjing 210095, China
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Liu Y, Yang K, Qin Q, Lin G, Hu T, Xu Z, Wang S. G Protein α Subunit GpaB is Required for Asexual Development, Aflatoxin Biosynthesis and Pathogenicity by Regulating cAMP Signaling in Aspergillus flavus. Toxins (Basel) 2018. [PMID: 29534423 PMCID: PMC5869405 DOI: 10.3390/toxins10030117] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The heterotrimeric G proteins are critical for signal transduction and function in numerous biological processes including vegetative growth, asexual development and fungal virulence in fungi. Here, we identified four G protein alpha subunits (GanA, GpaB, FadA and GaoC) in the notorious Aflatoxin-producing fungus Aspergillus flavus. GanA, GpaB and FadA have homologues in other fungal species, while GaoC is a novel one. Here, we showed that the loss function of gpaB displayed a defect in conidiophore formation and considerably reduced expression levels of conidia-specific genes brlA and abaA. A decreased viability of cell wall integrity stress and oxidative stress were also found in the ∆gpaB mutant. More importantly, aflatoxin (AF) biosynthesis and infection on crop seeds were severely impaired in the gpaB-deficient mutant. Further analyses demonstrated that the intracellular cAMP levels significantly reduced in the gpaB-deficient mutant compared to wildtype strains. Additionally, an alteration of PKA activities in the ∆gpaB mutant was also found. Overall, our results indicated that GpaB played diverse roles in asexual sporulation, AF biosynthesis and virulence by regulating cAMP signaling in Aspergillus flavus.
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Affiliation(s)
- Yinghang Liu
- Fujian Key Laboratory of Pathogenic Fungi and Mycotoxins, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Kunlong Yang
- Fujian Key Laboratory of Pathogenic Fungi and Mycotoxins, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Qiuping Qin
- Fujian Key Laboratory of Pathogenic Fungi and Mycotoxins, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
- Xiamen Anjie Medical Data Technology Co. Ltd., Xiamen 361115, China.
| | - Guinan Lin
- Fujian Key Laboratory of Pathogenic Fungi and Mycotoxins, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Tianran Hu
- Fujian Key Laboratory of Pathogenic Fungi and Mycotoxins, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Zhangling Xu
- Fujian Key Laboratory of Pathogenic Fungi and Mycotoxins, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Shihua Wang
- Fujian Key Laboratory of Pathogenic Fungi and Mycotoxins, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
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Jung WH, Son YE, Oh SH, Fu C, Kim HS, Kwak JH, Cardenas ME, Heitman J, Park HS. Had1 Is Required for Cell Wall Integrity and Fungal Virulence in Cryptococcus neoformans. G3 (Bethesda) 2018; 8:643-652. [PMID: 29233914 PMCID: PMC5919746 DOI: 10.1534/g3.117.300444] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 12/07/2017] [Indexed: 12/16/2022]
Abstract
Calcineurin modulates environmental stress survival and virulence of the human fungal pathogen Cryptococcus neoformans Previously, we identified 44 putative calcineurin substrates, and proposed that the calcineurin pathway is branched to regulate targets including Crz1, Pbp1, and Puf4 in C. neoformans In this study, we characterized Had1, which is one of the putative calcineurin substrates belonging to the ubiquitously conserved haloacid dehalogenase β-phosphoglucomutase protein superfamily. Growth of the had1∆ mutant was found to be compromised at 38° or higher. In addition, the had1∆ mutant exhibited increased sensitivity to cell wall perturbing agents, including Congo Red and Calcofluor White, and to an endoplasmic reticulum stress inducer dithiothreitol. Virulence studies revealed that the had1 mutation results in attenuated virulence compared to the wild-type strain in a murine inhalation infection model. Genetic epistasis analysis revealed that Had1 and the zinc finger transcription factor Crz1 play roles in parallel pathways that orchestrate stress survival and fungal virulence. Overall, our results demonstrate that Had1 is a key regulator of thermotolerance, cell wall integrity, and virulence of C. neoformans.
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Affiliation(s)
- Won-Hee Jung
- School of Food Science and Biotechnology, Institute of Agricultural Science and Technology, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Ye-Eun Son
- School of Food Science and Biotechnology, Institute of Agricultural Science and Technology, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Sang-Hun Oh
- School of Life Science, Handong Global University, Pohang 37554, Republic of Korea
| | - Ci Fu
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina 27710
| | - Hye Shin Kim
- School of Life Science, Handong Global University, Pohang 37554, Republic of Korea
| | - Jin-Hwan Kwak
- School of Life Science, Handong Global University, Pohang 37554, Republic of Korea
| | - Maria E Cardenas
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina 27710
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina 27710
| | - Hee-Soo Park
- School of Food Science and Biotechnology, Institute of Agricultural Science and Technology, Kyungpook National University, Daegu 41566, Republic of Korea
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Squizani ED, Oliveira NK, Reuwsaat JCV, Marques BM, Lopes W, Gerber AL, de Vasconcelos ATR, Lev S, Djordjevic JT, Schrank A, Vainstein MH, Staats CC, Kmetzsch L. Cryptococcal dissemination to the central nervous system requires the vacuolar calcium transporter Pmc1. Cell Microbiol 2017; 20. [PMID: 29113016 DOI: 10.1111/cmi.12803] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 10/27/2017] [Accepted: 10/30/2017] [Indexed: 12/26/2022]
Abstract
Cryptococcus neoformans is a basidiomycetous yeast and the cause of cryptococcosis in immunocompromised individuals. The most severe form of the disease is meningoencephalitis, which is one of the leading causes of death in HIV/AIDS patients. In order to access the central nervous system, C. neoformans relies on the activity of certain virulence factors such as urease, which allows transmigration through the blood-brain barrier. In this study, we demonstrate that the calcium transporter Pmc1 enables C. neoformans to penetrate the central nervous system, because the pmc1 null mutant failed to infect and to survive within the brain parenchyma in a murine systemic infection model. To investigate potential alterations in transmigration pathways in these mutants, global expression profiling of the pmc1 mutant strain was undertaken, and genes associated with urease, the Ca2+ -calcineurin pathway, and capsule assembly were identified as being differentially expressed. Also, a decrease in urease activity was observed in the calcium transporter null mutants. Finally, we demonstrate that the transcription factor Crz1 regulates urease activity and that the Ca2+ -calcineurin signalling pathway positively controls the transcription of calcium transporter genes and factors related to transmigration.
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Affiliation(s)
| | | | | | | | - William Lopes
- Centro de Biotecnologia, UFRGS, Porto Alegre, RS, Brazil
| | - Alexandra L Gerber
- Laboratório Nacional de Computação Científica (LNCC), Petrópolis, RJ, Brazil
| | | | - Sophie Lev
- Fungal Pathogenesis Laboratory, Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Westmead, NSW, Australia
| | - Julianne T Djordjevic
- Fungal Pathogenesis Laboratory, Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Westmead, NSW, Australia
| | | | | | | | - Lívia Kmetzsch
- Centro de Biotecnologia, UFRGS, Porto Alegre, RS, Brazil
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49
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Abstract
Invasive fungal infections are a growing threat to immunocompromised patients, highlighting the importance of monitoring fungal pathogens. Global warming (including climatic oscillations) may select for environmental species that have acquired thermotolerance, a key step toward pathogenesis to humans. Also, important virulence factors have developed in environmental fungi, because they are essential for yeast survival in the environment. Thus, fungi traditionally regarded as nonpathogenic to humans have virulence factors similar to those of their pathogenic relatives. Here, we highlight the emergence of saprophytic environmental fungi - including species of Cryptococcus, Aspergillus, Penicillium, Candida and Scedosporium - as new human pathogens. Emerging pathogens are, in some cases, resistant to the available antifungals, potentiating the threat of novel fungal diseases.
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Affiliation(s)
- Glauber R de S Araújo
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Wanderley de Souza
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Susana Frases
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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50
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Quoc NB, Chau NNB. The Role of Cell Wall Degrading Enzymes in Pathogenesis of Magnaporthe oryzae. Curr Protein Pept Sci 2017; 18:1019-1034. [PMID: 27526928 DOI: 10.2174/1389203717666160813164955] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Revised: 07/15/2016] [Accepted: 07/27/2016] [Indexed: 11/22/2022]
Abstract
The plant cell wall is always the physical barrier in which phytopathogenic fungi must overcome by producing an array of cell wall degrading enzymes (CWDEs) that allow them to invade host tissues through the degradation of cell wall components of plants. Magnaporthe oryzae is a causal agent of blast disease, one of the most devastating disease in rice resulting significant crop losses worldwide. The penetration of plant cuticle and cell walls induced by infection structures of M. oryzae has been known to be acquired by the association of turgor pressure and CWDEs for successful infection of M. oryzae. In this review, we focus on recent discoveries of M. oryzae CWDEs, gene regulation and their biological roles as fungal virulence factors and elicitors of host defense response leading to plant resistance against fungal pathogens.
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Affiliation(s)
- Nguyen Bao Quoc
- Research Institute for Biotechnology and Environment, Nong Lam University, Ho Chi Minh City. Vietnam
| | - Nguyen Ngoc Bao Chau
- Faculty of Biotechnology, Ho Chi Minh City Open University, Ho Chi Minh City. Vietnam
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