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Li X, Feng R, Luo P, Zhang Y, Lu L. Synergistic effects of putative Ca 2+-binding sites of calmodulin in fungal development, temperature stress and virulence of Aspergillus fumigatus. Virulence 2024; 15:2290757. [PMID: 38085844 PMCID: PMC10761034 DOI: 10.1080/21505594.2023.2290757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 11/28/2023] [Indexed: 12/18/2023] Open
Abstract
In pathogenic fungi, calcium-calmodulin-dependent serine-threonine-specific phosphatase calcineurin is involved in morphogenesis and virulence. Therefore, calcineurin and its tightly related protein complexes are attractive antifungal drug targets. However, there is limited knowledge available on the relationship between in vivo Ca2+-binding sites of calmodulin (CaM) and its functions in regulating stress responses, morphogenesis, and pathogenesis. In the current study, we demonstrated that calmodulin is required for hyphal growth, conidiation, and virulence in the human fungal pathogen, Aspergillus fumigatus. Site-directed mutations of calmodulin revealed that a single Ca2+-binding site mutation had no significant effect on A. fumigatus hyphal development, but multiple Ca2+-binding site mutations exhibited synergistic effects, especially when cultured at 42 °C, indicating that calmodulin function in response to temperature stress depends on its Ca2+-binding sites. Western blotting implied that mutations in Ca2+-binding sites caused highly degraded calmodulin fragments, suggesting that the loss of Ca2+-binding sites results in reduced protein stability. Moreover, normal intracellular calcium homeostasis and the nuclear translocation of the transcriptional factor CrzA are dependent on Ca2+-binding sites of AfCaM, demonstrating that Ca2+-binding sites of calmodulin are required for calcium signalling and its major transcription factor CrzA. Importantly, in situ mutations for four Ca2+-binding sites of calmodulin resulted in an almost complete loss of virulence in the Galleria mellonella wax moth model. This study shed more light on the functional characterization of putative calcium-binding sites of calmodulin in the morphogenesis and virulence of A. fumigatus, which enhances our understanding of calmodulin biological functions in cells of opportunistic fungal pathogens.
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Affiliation(s)
- Xingyue Li
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Ruoyun Feng
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Pan Luo
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Yuanwei Zhang
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Ling Lu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China
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2
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Amatto IVDS, Simões FADO, Garzon NGDR, Marciano CL, Silva RRD, Cabral H. Response of Fusarium oxysporum soil isolate to amphotericin B and fluconazole at the proteomic level. Braz J Microbiol 2024:10.1007/s42770-024-01417-8. [PMID: 38954219 DOI: 10.1007/s42770-024-01417-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Accepted: 06/04/2024] [Indexed: 07/04/2024] Open
Abstract
Fusarium oxysporum is a cross-kingdom pathogen that infects humans, animals, and plants. The primary concern regarding this genus revolves around its resistance profile to multiple classes of antifungals, particularly azoles. However, the resistance mechanism employed by Fusarium spp. is not fully understood, thus necessitating further studies to enhance our understanding and to guide future research towards identifying new drug targets. Here, we employed an untargeted proteomic approach to assess the differentially expressed proteins in a soil isolate of Fusarium oxysporum URM7401 cultivated in the presence of amphotericin B and fluconazole. In response to antifungals, URM7401 activated diverse interconnected pathways, such as proteins involved in oxidative stress response, proteolysis, and lipid metabolism. Efflux proteins, antioxidative enzymes and M35 metallopeptidase were highly expressed under amphotericin B exposure. Antioxidant proteins acting on toxic lipids, along with proteins involved in lipid metabolism, were expressed during fluconazole exposure. In summary, this work describes the protein profile of a resistant Fusarium oxysporum soil isolate exposed to medical antifungals, paving the way for further targeted research and discovering new drug targets.
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Affiliation(s)
- I V da S Amatto
- Department of Pharmaceutical Sciences, School of Pharmaceutical Sciences, University of São Paulo, Ribeirão Preto, Brazil
| | - F A de O Simões
- Department of Pharmaceutical Sciences, School of Pharmaceutical Sciences, University of São Paulo, Ribeirão Preto, Brazil
| | - N G da R Garzon
- Department of Pharmaceutical Sciences, School of Pharmaceutical Sciences, University of São Paulo, Ribeirão Preto, Brazil
| | - C L Marciano
- Department of Pharmaceutical Sciences, School of Pharmaceutical Sciences, University of São Paulo, Ribeirão Preto, Brazil
| | - R R da Silva
- Department of Molecular Biosciences, School of Pharmaceutical Sciences, University of São, Ribeirão Preto, Brazil
| | - H Cabral
- Department of Pharmaceutical Sciences, School of Pharmaceutical Sciences, University of São Paulo, Ribeirão Preto, Brazil.
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3
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Gluck-Thaler E, Forsythe A, Puerner C, Stajich JE, Croll D, Cramer RA, Vogan AA. Giant transposons promote strain heterogeneity in a major fungal pathogen. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.28.601215. [PMID: 38979181 PMCID: PMC11230402 DOI: 10.1101/2024.06.28.601215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Fungal infections are difficult to prevent and treat in large part due to heterogeneity in clinically relevant phenotypes. However, the genetic mechanisms driving pathogen variation remain poorly understood. Here, we determined the extent to which Starships -giant transposons capable of mobilizing numerous fungal genes-generate genetic and phenotypic variability in the human pathogen Aspergillus fumigatus . We analyzed 519 diverse strains, including 12 newly sequenced with long-read technology, to reveal 20 distinct Starships that generate genomic heterogeneity over timescales impacting experimental reproducibility. Starship -mobilized genes encode diverse functions, including biofilm-related virulence factors and biosynthetic gene clusters, and many are differentially expressed during infection and antifungal exposure in a strain-specific manner. These findings support a new model of fungal pathogenesis wherein Starships mediate variation in virulence-related gene content and expression. Together, our results demonstrate that Starships are a foundational mechanism generating disease-relevant genotypic and, in turn, phenotypic heterogeneity in a major human fungal pathogen.
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Gandham P, Rajasekaran K, Sickler C, Mohan H, Gilbert M, Baisakh N. MicroRNA (miRNA) profiling of maize genotypes with differential response to Aspergillus flavus implies zma-miR156-squamosa promoter binding protein (SBP) and zma-miR398/zma-miR394-F -box combinations involved in resistance mechanisms. STRESS BIOLOGY 2024; 4:26. [PMID: 38727957 PMCID: PMC11087424 DOI: 10.1007/s44154-024-00158-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 03/05/2024] [Indexed: 05/13/2024]
Abstract
Maize (Zea mays), a major food crop worldwide, is susceptible to infection by the saprophytic fungus Aspergillus flavus that can produce the carcinogenic metabolite aflatoxin (AF) especially under climate change induced abiotic stressors that favor mold growth. Several studies have used "-omics" approaches to identify genetic elements with potential roles in AF resistance, but there is a lack of research identifying the involvement of small RNAs such as microRNAs (miRNAs) in maize-A. flavus interaction. In this study, we compared the miRNA profiles of three maize lines (resistant TZAR102, moderately resistant MI82, and susceptible Va35) at 8 h, 3 d, and 7 d after A. flavus infection to investigate possible regulatory antifungal role of miRNAs. A total of 316 miRNAs (275 known and 41 putative novel) belonging to 115 miRNA families were identified in response to the fungal infection across all three maize lines. Eighty-two unique miRNAs were significantly differentially expressed with 39 miRNAs exhibiting temporal differential regulation irrespective of the maize genotype, which targeted 544 genes (mRNAs) involved in diverse molecular functions. The two most notable biological processes involved in plant immunity, namely cellular responses to oxidative stress (GO:00345990) and reactive oxygen species (GO:0034614) were significantly enriched in the resistant line TZAR102. Coexpression network analysis identified 34 hubs of miRNA-mRNA pairs where nine hubs had a node in the module connected to their target gene with potentially important roles in resistance/susceptible response of maize to A. flavus. The miRNA hubs in resistance modules (TZAR102 and MI82) were mostly connected to transcription factors and protein kinases. Specifically, the module of miRNA zma-miR156b-nb - squamosa promoter binding protein (SBP), zma-miR398a-3p - SKIP5, and zma-miR394a-5p - F-box protein 6 combinations in the resistance-associated modules were considered important candidates for future functional studies.
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Affiliation(s)
- Prasad Gandham
- School of Plant, Environmental and Soil Sciences, Louisiana State University Agricultural Center, Baton Rouge, LA, 70803, USA
| | - Kanniah Rajasekaran
- Food and Feed Safety Research Unit, Southern Regional Research Center, USDA-ARS, New Orleans, LA, 70726, USA.
| | - Christine Sickler
- Food and Feed Safety Research Unit, Southern Regional Research Center, USDA-ARS, New Orleans, LA, 70726, USA
| | - Harikrishnan Mohan
- School of Plant, Environmental and Soil Sciences, Louisiana State University Agricultural Center, Baton Rouge, LA, 70803, USA
| | - Matthew Gilbert
- Food and Feed Safety Research Unit, Southern Regional Research Center, USDA-ARS, New Orleans, LA, 70726, USA
| | - Niranjan Baisakh
- School of Plant, Environmental and Soil Sciences, Louisiana State University Agricultural Center, Baton Rouge, LA, 70803, USA.
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5
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Son YE, Han J, Lee KT, Park HS. Pleiotropic functions of SscA on the asexual spore of the human pathogenic fungus Aspergillus fumigatus. Mycology 2023; 15:238-254. [PMID: 38813476 PMCID: PMC11132850 DOI: 10.1080/21501203.2023.2294061] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 12/06/2023] [Indexed: 05/31/2024] Open
Abstract
Asexual spores, called conidia, are key reproductive fungal particles that enable survival in harsh environmental conditions or host systems. The conidia can infect humans, animals, and plants to cause various fungal diseases. Transcription factors, including VosA, WetA, and SscA, have key roles in conidia formation and long-term survival in Aspergillus nidulans. Herein, we report the pleiotropic functions of SscA in the conidia of the human pathogen A. fumigatus. The deletion of sscA increased conidia formation despite decreased fungal growth. Absence of sscA impaired long-term survival and reduced spore resistance to various stresses, including heat, UV, and oxidation. Transcriptomic analyses showed that SscA involved the mRNA expression of cell wall organisation-related genes. Importantly, the sscA deletion mutant conidia contained an increased amount of β-glucan and chitin compared to wild type conidia. In addition, conidial gliotoxin production was decreased in the sscA deletion strain. Overall, SscA has pleiotropic roles in conidia formation, maturation and dormancy and mycotoxin production in A. fumigatus.
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Affiliation(s)
- Ye-Eun Son
- School of Food Science and Biotechnology, Kyungpook National University, Daegu, Republic of Korea
| | - Jiwoo Han
- Korea Zoonosis Research Institute, Jeonbuk National University, Iksan, Republic of Korea
| | - Kyung-Tae Lee
- Korea Zoonosis Research Institute, Jeonbuk National University, Iksan, Republic of Korea
| | - Hee-Soo Park
- School of Food Science and Biotechnology, Kyungpook National University, Daegu, Republic of Korea
- Department of Integrative Biology, Kyungpook National University, Daegu, Republic of Korea
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Webb RJ, Rush C, Berger L, Skerratt LF, Roberts AA. Glutathione is required for growth and cadmium tolerance in the amphibian chytrid fungus, Batrachochytrium dendrobatidis. Biochimie 2023; 220:22-30. [PMID: 38104714 DOI: 10.1016/j.biochi.2023.12.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 11/24/2023] [Accepted: 12/12/2023] [Indexed: 12/19/2023]
Abstract
Batrachochytrium dendrobatidis (Bd) is a lethal amphibian pathogen, partly due to its ability to evade the immune system of susceptible frog species. In many pathogenic fungi, the antioxidant glutathione is a virulence factor that helps neutralise oxidative stressors generated from host immune cells, as well as other environmental stressors such as heavy metals. The role of glutathione in stress tolerance in Bd has not been investigated. Here, we examine the changes in the glutathione pool after stress exposure and quantify the effect of glutathione depletion on cell growth and stress tolerance. Depletion of glutathione repressed growth and release of zoospores, suggesting that glutathione is essential for life cycle completion in Bd. Supplementation with <2 mM exogenous glutathione accelerated zoospore development, but concentrations >2 mM were strongly inhibitory to Bd cells. While hydrogen peroxide exposure lowered the total cellular glutathione levels by 42 %, glutathione depletion did not increase the sensitivity to hydrogen peroxide. Exposure to cadmium increased total cellular glutathione levels by 93 %. Glutathione-depleted cells were more sensitive to cadmium, and this effect was attenuated by glutathione supplementation, suggesting that glutathione plays an important role in cadmium tolerance. The effects of heat and salt were exacerbated by the addition of exogenous glutathione. The impact of glutathione levels on Bd stress sensitivity may help explain differences in host susceptibility to chytridiomycosis and may provide opportunities for synergistic therapeutics.
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Affiliation(s)
- Rebecca J Webb
- James Cook University, Townsville, QLD, 4811, Australia; Melbourne Veterinary School, University of Melbourne, Werribee, VIC, 3030, Australia.
| | | | - Lee Berger
- Melbourne Veterinary School, University of Melbourne, Werribee, VIC, 3030, Australia
| | - Lee F Skerratt
- Melbourne Veterinary School, University of Melbourne, Werribee, VIC, 3030, Australia
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Earle K, Valero C, Conn DP, Vere G, Cook PC, Bromley MJ, Bowyer P, Gago S. Pathogenicity and virulence of Aspergillus fumigatus. Virulence 2023; 14:2172264. [PMID: 36752587 PMCID: PMC10732619 DOI: 10.1080/21505594.2023.2172264] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 12/16/2022] [Indexed: 02/09/2023] Open
Abstract
Pulmonary infections caused by the mould pathogen Aspergillus fumigatus are a major cause of morbidity and mortality globally. Compromised lung defences arising from immunosuppression, chronic respiratory conditions or more recently, concomitant viral or bacterial pulmonary infections are recognised risks factors for the development of pulmonary aspergillosis. In this review, we will summarise our current knowledge of the mechanistic basis of pulmonary aspergillosis with a focus on emerging at-risk populations.
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Affiliation(s)
- Kayleigh Earle
- Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Clara Valero
- Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Daniel P. Conn
- MRC Centre for Medical Mycology, University of Exeter, Exeter, UK
| | - George Vere
- MRC Centre for Medical Mycology, University of Exeter, Exeter, UK
| | - Peter C. Cook
- MRC Centre for Medical Mycology, University of Exeter, Exeter, UK
| | - Michael J. Bromley
- Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Paul Bowyer
- Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Sara Gago
- Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
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Romero V, Kalinhoff C, Saa LR, Sánchez A. Fungi's Swiss Army Knife: Pleiotropic Effect of Melanin in Fungal Pathogenesis during Cattle Mycosis. J Fungi (Basel) 2023; 9:929. [PMID: 37755037 PMCID: PMC10532448 DOI: 10.3390/jof9090929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 09/05/2023] [Accepted: 09/08/2023] [Indexed: 09/28/2023] Open
Abstract
Fungal threats to public health, food security, and biodiversity have escalated, with a significant rise in mycosis cases globally. Around 300 million people suffer from severe fungal diseases annually, while one-third of food crops are decimated by fungi. Vertebrate, including livestock, are also affected. Our limited understanding of fungal virulence mechanisms hampers our ability to prevent and treat cattle mycoses. Here we aim to bridge knowledge gaps in fungal virulence factors and the role of melanin in evading bovine immune responses. We investigate mycosis in bovines employing a PRISMA-based methodology, bioinformatics, and data mining techniques. Our analysis identified 107 fungal species causing mycoses, primarily within the Ascomycota division. Candida, Aspergillus, Malassezia, and Trichophyton were the most prevalent genera. Of these pathogens, 25% produce melanin. Further research is required to explore the involvement of melanin and develop intervention strategies. While the literature on melanin-mediated fungal evasion mechanisms in cattle is lacking, we successfully evaluated the transferability of immunological mechanisms from other model mammals through homology. Bioinformatics enables knowledge transfer and enhances our understanding of mycosis in cattle. This synthesis fills critical information gaps and paves the way for proposing biotechnological strategies to mitigate the impact of mycoses in cattle.
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Affiliation(s)
- Víctor Romero
- Maestría en Biotecnología Agropecuaria, Universidad Técnica Particular de Loja, San Cayetano Alto, Calle París s/n, Loja 1101608, Ecuador
- Museo de Zoología, Universidad Técnica Particular de Loja, San Cayetano Alto, Calle París s/n, Loja 1101608, Ecuador
| | - Carolina Kalinhoff
- Departamento de Ciencias Biológicas y Agropecuarias, Facultad de Ciencias Exactas y Naturales, Universidad Técnica Particular de Loja, San Cayetano Alto, Calle París s/n, Loja 1101608, Ecuador; (C.K.)
| | - Luis Rodrigo Saa
- Departamento de Ciencias Biológicas y Agropecuarias, Facultad de Ciencias Exactas y Naturales, Universidad Técnica Particular de Loja, San Cayetano Alto, Calle París s/n, Loja 1101608, Ecuador; (C.K.)
| | - Aminael Sánchez
- Departamento de Ciencias Biológicas y Agropecuarias, Facultad de Ciencias Exactas y Naturales, Universidad Técnica Particular de Loja, San Cayetano Alto, Calle París s/n, Loja 1101608, Ecuador; (C.K.)
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9
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Oneissi M, Cruz MR, Ramírez-Zavala B, Lindemann-Perez E, Morschhäuser J, Garsin DA, Perez JC. Host-derived reactive oxygen species trigger activation of the Candida albicans transcription regulator Rtg1/3. PLoS Pathog 2023; 19:e1011692. [PMID: 37769015 PMCID: PMC10564244 DOI: 10.1371/journal.ppat.1011692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 10/10/2023] [Accepted: 09/18/2023] [Indexed: 09/30/2023] Open
Abstract
The signals that denote mammalian host environments and dictate the activation of signaling pathways in human-associated microorganisms are often unknown. The transcription regulator Rtg1/3 in the human fungal pathogen Candida albicans is a crucial determinant of host colonization and pathogenicity. Rtg1/3's activity is controlled, in part, by shuttling the regulator between the cytoplasm and nucleus of the fungus. The host signal(s) that Rtg1/3 respond(s) to, however, have remained unclear. Here we report that neutrophil-derived reactive oxygen species (ROS) direct the subcellular localization of this C. albicans transcription regulator. Upon engulfment of Candida cells by human or mouse neutrophils, the regulator shuttles to the fungal nucleus. Using genetic and chemical approaches to disrupt the neutrophils' oxidative burst, we establish that the oxidants produced by the NOX2 complex-but not the oxidants generated by myeloperoxidase-trigger Rtg1/3's migration to the nucleus. Furthermore, screening a collection of C. albicans kinase deletion mutants, we implicate the MKC1 signaling pathway in the ROS-dependent regulation of Rtg1/3 in this fungus. Finally, we show that Rtg1/3 contributes to C. albicans virulence in the nematode Caenorhabditis elegans in an ROS-dependent manner as the rtg1 and rtg3 mutants display virulence defects in wild-type but not in ROS deficient worms. Our findings establish NOX2-derived ROS as a key signal that directs the activity of the pleiotropic fungal regulator Rtg1/3.
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Affiliation(s)
- Mazen Oneissi
- Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, United States of America
| | - Melissa R. Cruz
- Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, United States of America
| | | | - Elena Lindemann-Perez
- Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, United States of America
| | - Joachim Morschhäuser
- Institute of Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Danielle A. Garsin
- Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, United States of America
| | - J. Christian Perez
- Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, United States of America
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Tan J, Zhang H, Sun Y, Gao L. Afu-Emi1 Contributes to Stress Adaptation and Voriconazole Susceptibility in Aspergillus fumigatus. Microbiol Spectr 2023; 11:e0095623. [PMID: 37039674 PMCID: PMC10269808 DOI: 10.1128/spectrum.00956-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 03/17/2023] [Indexed: 04/12/2023] Open
Abstract
Invasive aspergillosis (IA) is the second most common invasive fungal disease and is associated with high mortality rates. Aspergillus fumigatus is the predominant causal agent of this life-threatening infection. Triazoles are still the cornerstone of antifungal treatment, and voriconazole remains the first-line choice. However, voriconazole resistance has been increasingly reported, which results in significantly higher mortality rates for IA and is particularly problematic. In the present study, we report the identification and functional study of a protein with previously unknown function that is encoded by the gene designated Afu-emi1 (AFUA_1G07360). High-throughput gene replacement technology was applied to construct the knockout ΔAfu-emi1 strain and a revertant strain. The MICs for azoles, including posaconazole, itraconazole, and voriconazole, were evaluated via the broth microdilution method and E-tests, which revealed that disruption of Afu-emi1 resulted in 4-fold increased susceptibility to voriconazole. Colony growth in the presence of oxidants, namely, H2O2 and menadione, and osmotic pressure-altering agents, namely, NaCl and d-sorbitol, was measured. The Afu-emi1 mutant strain exhibited a significant growth defect under oxidative and osmotic stress. The reactive oxygen species (ROS) production levels with or without voriconazole pretreatment were determined, and the Afu-emi1 mutant strain exhibited significantly lower ROS production levels. The effects of Afu-emi1 disruption on voriconazole susceptibility, growth under stress, and ROS production were restored in the revertant strain. In addition, the expression of cyp51A, AfuMDR2, AfuMDR3, AfuMDR4, and cdr1b in the ΔAfu-emi1 strain was significantly reduced. In conclusion, deletion of the gene Afu-emi1 resulted in increased voriconazole susceptibility, attenuated ability for oxidative and osmotic stress adaptation, decreased ROS production, and downregulation of cyp51A, AfuMDR2, AfuMDR3, AfuMDR4, and cdr1b expression, suggesting that Afu-Emi1 is an important regulator of stress adaptation and cyp51A and efflux pump expression in this medically important fungus. IMPORTANCE Voriconazole is the first-line choice for IA, a life-threatening disease. Therefore, voriconazole resistance has become particularly problematic. Disruption of Afu-emi1 resulted in increased susceptibility to voriconazole, a significant growth defect under oxidative and osmotic stress, and downregulation of target enzyme Cyp51A and efflux pump expression, suggesting that Afu-Emi1 is an important regulator of stress adaptation and cyp51A and efflux pump expression in this medically important fungus. Targeting Afu-Emi1 might help to enhance azole therapeutic efficacy and impede azole resistance.
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Affiliation(s)
- Jufang Tan
- Department of Neonatology, Jingzhou Hospital Affiliated to Yangtze University, Jingzhou, Hubei Province, China
| | - Heng Zhang
- Department of Surgery, Jingzhou Hospital Affiliated to Yangtze University, Jingzhou, Hubei Province, China
| | - Yi Sun
- Department of Dermatology, Jingzhou Hospital Affiliated to Yangtze University, Jingzhou, Hubei Province, China
| | - Lujuan Gao
- Department of Dermatology, Zhongshan Hospital, Fudan University, Shanghai, China
- Department of Dermatology, Zhongshan Hospital (Xiamen), Fudan University, Xiamen, Fujian Province, China
- Xiamen Clinical Research Center for Cancer Therapy, Xiamen, Fujian Province, China
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11
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Dos Reis TF, de Castro PA, Bastos RW, Pinzan CF, Souza PFN, Ackloo S, Hossain MA, Drewry DH, Alkhazraji S, Ibrahim AS, Jo H, Lightfoot JD, Adams EM, Fuller KK, deGrado WF, Goldman GH. A host defense peptide mimetic, brilacidin, potentiates caspofungin antifungal activity against human pathogenic fungi. Nat Commun 2023; 14:2052. [PMID: 37045836 PMCID: PMC10090755 DOI: 10.1038/s41467-023-37573-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 03/23/2023] [Indexed: 04/14/2023] Open
Abstract
Fungal infections cause more than 1.5 million deaths a year. Due to emerging antifungal drug resistance, novel strategies are urgently needed to combat life-threatening fungal diseases. Here, we identify the host defense peptide mimetic, brilacidin (BRI) as a synergizer with caspofungin (CAS) against CAS-sensitive and CAS-resistant isolates of Aspergillus fumigatus, Candida albicans, C. auris, and CAS-intrinsically resistant Cryptococcus neoformans. BRI also potentiates azoles against A. fumigatus and several Mucorales fungi. BRI acts in A. fumigatus by affecting cell wall integrity pathway and cell membrane potential. BRI combined with CAS significantly clears A. fumigatus lung infection in an immunosuppressed murine model of invasive pulmonary aspergillosis. BRI alone also decreases A. fumigatus fungal burden and ablates disease development in a murine model of fungal keratitis. Our results indicate that combinations of BRI and antifungal drugs in clinical use are likely to improve the treatment outcome of aspergillosis and other fungal infections.
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Affiliation(s)
- Thaila Fernanda Dos Reis
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Patrícia Alves de Castro
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Rafael Wesley Bastos
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Camila Figueiredo Pinzan
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Pedro F N Souza
- Visiting professor at Drug Research and Development Center, Department of Physiology and Pharmacology, Federal University of Ceará, Fortaleza, Ceará, 60451, Brazil
| | - Suzanne Ackloo
- Structural Genomics Consortium, University of Toronto, 101 College Street, MaRS South Tower, Suite 700, Toronto, ON, M5G 1L7, Canada
| | - Mohammad Anwar Hossain
- Structural Genomics Consortium, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - David Harold Drewry
- Structural Genomics Consortium, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
- Lineberger Comprehensive Cancer Center, Department of Medicine, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Sondus Alkhazraji
- Division of Infectious Diseases, The Lundquist Institute for Biomedical Innovation at Harbor-University of California Los Angeles (UCLA) Medical Center, Torrance, CA, 90502, USA
| | - Ashraf S Ibrahim
- Division of Infectious Diseases, The Lundquist Institute for Biomedical Innovation at Harbor-University of California Los Angeles (UCLA) Medical Center, Torrance, CA, 90502, USA
- David Geffen School of Medicine at UCLA, Los Angeles, CA, 90095, USA
| | - Hyunil Jo
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, 94143, USA
| | - Jorge D Lightfoot
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Emily M Adams
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Kevin K Fuller
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - William F deGrado
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, 94143, USA
| | - Gustavo H Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil.
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12
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Mead ME, de Castro PA, Steenwyk JL, Gangneux JP, Hoenigl M, Prattes J, Rautemaa-Richardson R, Guegan H, Moore CB, Lass-Flörl C, Reizine F, Valero C, Van Rhijn N, Bromley MJ, Rokas A, Goldman GH, Gago S. COVID-19-Associated Pulmonary Aspergillosis Isolates Are Genomically Diverse but Similar to Each Other in Their Responses to Infection-Relevant Stresses. Microbiol Spectr 2023; 11:e0512822. [PMID: 36946762 PMCID: PMC10100753 DOI: 10.1128/spectrum.05128-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 02/25/2023] [Indexed: 03/23/2023] Open
Abstract
Secondary infections caused by the pulmonary fungal pathogen Aspergillus fumigatus are a significant cause of mortality in patients with severe coronavirus disease 19 (COVID-19). Even though epithelial cell damage and aberrant cytokine responses have been linked to susceptibility to COVID-19-associated pulmonary aspergillosis (CAPA), little is known about the mechanisms underpinning copathogenicity. Here, we analyzed the genomes of 11 A. fumigatus isolates from patients with CAPA in three centers from different European countries. CAPA isolates did not cluster based on geographic origin in a genome-scale phylogeny of representative A. fumigatus isolates. Phenotypically, CAPA isolates were more similar to the A. fumigatus A1160 reference strain than to the Af293 strain when grown in infection-relevant stresses, except for interactions with human immune cells wherein macrophage responses were similar to those induced by the Af293 reference strain. Collectively, our data indicate that CAPA isolates are genomically diverse but are more similar to each other in their responses to infection-relevant stresses. A larger number of isolates from CAPA patients should be studied to better understand the molecular epidemiology of CAPA and to identify genetic drivers of copathogenicity and antifungal resistance in patients with COVID-19. IMPORTANCE Coronavirus disease 2019 (COVID-19)-associated pulmonary aspergillosis (CAPA) has been globally reported as a life-threatening complication in some patients with severe COVID-19. Most of these infections are caused by the environmental mold Aspergillus fumigatus, which ranks third in the fungal pathogen priority list of the WHO. However, little is known about the molecular epidemiology of Aspergillus fumigatus CAPA strains. Here, we analyzed the genomes of 11 A. fumigatus isolates from patients with CAPA in three centers from different European countries, and carried out phenotypic analyses with a view to understanding the pathophysiology of the disease. Our data indicate that A. fumigatus CAPA isolates are genomically diverse but are more similar to each other in their responses to infection-relevant stresses.
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Affiliation(s)
- Matthew E. Mead
- Department of Biological Sciences and Evolutionary Studies Initiative, Vanderbilt University, Nashville, Tennessee, USA
| | - Patrícia Alves de Castro
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Jacob L. Steenwyk
- Department of Biological Sciences and Evolutionary Studies Initiative, Vanderbilt University, Nashville, Tennessee, USA
| | - Jean-Pierre Gangneux
- University of Rennes, CHU Rennes, Inserm, EHESP, IRSET (Institut de recherche en santé, environnement et travail), Rennes, France
| | - Martin Hoenigl
- Division of Infectious Diseases, Medical University of Graz, Graz, Austria
- Biotech Med, Graz, Austria
| | - Juergen Prattes
- Division of Infectious Diseases, Medical University of Graz, Graz, Austria
| | - Riina Rautemaa-Richardson
- Mycology Reference Centre Manchester and Department of Infectious Diseases, Manchester University, Manchester University NHS Foundation Trust, Wythenshawe Hospital, Manchester, United Kingdom
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Hélène Guegan
- University of Rennes, CHU Rennes, Inserm, EHESP, IRSET (Institut de recherche en santé, environnement et travail), Rennes, France
| | - Caroline B. Moore
- Mycology Reference Centre Manchester and Department of Infectious Diseases, Manchester University, Manchester University NHS Foundation Trust, Wythenshawe Hospital, Manchester, United Kingdom
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Cornelia Lass-Flörl
- European Excellence Center for Medical Mycology (ECMM), Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, Austria
| | - Florian Reizine
- University of Rennes, CHU Rennes, Inserm, EHESP, IRSET (Institut de recherche en santé, environnement et travail), Rennes, France
- Medical Intensive Care Unit, Rennes University Hospital, Rennes, France
| | - Clara Valero
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
- Manchester Fungal Infection Group, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Norman Van Rhijn
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
- Manchester Fungal Infection Group, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Michael J. Bromley
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
- Manchester Fungal Infection Group, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Antonis Rokas
- Department of Biological Sciences and Evolutionary Studies Initiative, Vanderbilt University, Nashville, Tennessee, USA
| | - Gustavo H. Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Sara Gago
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
- Manchester Fungal Infection Group, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - on behalf of the ECMM CAPA Study Group
- Department of Biological Sciences and Evolutionary Studies Initiative, Vanderbilt University, Nashville, Tennessee, USA
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
- University of Rennes, CHU Rennes, Inserm, EHESP, IRSET (Institut de recherche en santé, environnement et travail), Rennes, France
- Division of Infectious Diseases, Medical University of Graz, Graz, Austria
- Biotech Med, Graz, Austria
- Mycology Reference Centre Manchester and Department of Infectious Diseases, Manchester University, Manchester University NHS Foundation Trust, Wythenshawe Hospital, Manchester, United Kingdom
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
- European Excellence Center for Medical Mycology (ECMM), Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, Austria
- Medical Intensive Care Unit, Rennes University Hospital, Rennes, France
- Manchester Fungal Infection Group, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
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13
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Putative Core Transcription Factors Affecting Virulence in Aspergillus flavus during Infection of Maize. J Fungi (Basel) 2023; 9:jof9010118. [PMID: 36675939 PMCID: PMC9861280 DOI: 10.3390/jof9010118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 12/20/2022] [Accepted: 12/23/2022] [Indexed: 01/17/2023] Open
Abstract
Aspergillus flavus is an opportunistic pathogen responsible for millions of dollars in crop losses annually and negative health impacts on crop consumers globally. A. flavus strains have the potential to produce aflatoxin and other toxic secondary metabolites, which often increase during plant colonization. To mitigate the impacts of this international issue, we employ a range of strategies to directly impact fungal physiology, growth and development, thus requiring knowledge on the underlying molecular mechanisms driving these processes. Here we utilize RNA-sequencing data that are obtained from in situ assays, whereby Zea mays kernels are inoculated with A. flavus strains, to select transcription factors putatively driving virulence-related gene networks. We demonstrate, through growth, sporulation, oxidative stress-response and aflatoxin/CPA analysis, that three A. flavus strains with knockout mutations for the putative transcription factors AFLA_089270, AFLA_112760, and AFLA_031450 demonstrate characteristics such as reduced growth capacity and decreased aflatoxin/CPA accumulation in kernels consistent with decreased fungal pathogenicity. Furthermore, AFLA_089270, also known as HacA, eliminates CPA production and impacts the fungus's capacity to respond to highly oxidative conditions, indicating an impact on plant colonization. Taken together, these data provide a sound foundation for elucidating the downstream molecular pathways potentially contributing to fungal virulence.
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14
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Emri T, Antal K, Gila B, Jónás AP, Pócsi I. Stress Responses Elicited by Glucose Withdrawal in Aspergillus fumigatus. J Fungi (Basel) 2022; 8:jof8111226. [PMID: 36422047 PMCID: PMC9692504 DOI: 10.3390/jof8111226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 11/15/2022] [Accepted: 11/16/2022] [Indexed: 11/22/2022] Open
Abstract
Glucose is a widely used carbon source in laboratory practice to culture Aspergillus fumigatus, however, glucose availability is often low in its “natural habitats”, including the human body. We used a physiological−transcriptomical approach to reveal differences between A. fumigatus Af293 cultures incubated on glucose, glucose and peptone, peptone (carbon limitation), or without any carbon source (carbon starvation). Autolytic cell wall degradation was upregulated by both carbon starvation and limitation. The importance of autolytic cell wall degradation in the adaptation to carbon stress was also highlighted by approximately 12.4% of the A. fumigatus genomes harboring duplication of genes involved in N-acetyl glucosamine utilization. Glucose withdrawal increased redox imbalance, altered both the transcription of antioxidative enzyme genes and oxidative stress tolerance, and downregulated iron acquisition, but upregulated heme protein genes. Transcriptional activity of the Gliotoxin cluster was low in all experiments, while the Fumagillin cluster showed substantial activity both on glucose and under carbon starvation, and the Hexadehydro-astechrome cluster only on glucose. We concluded that glucose withdrawal substantially modified the physiology of A. fumigatus, including processes that contribute to virulence. This may explain the challenge of predicting the in vivo behavior of A. fumigatus based on data from glucose rich cultures.
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Affiliation(s)
- Tamás Emri
- Department of Molecular Biotechnology and Microbiology, Faculty of Sciences and Technology, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
- ELRN-UD Fungal Stress Biology Research Group, Egyetem tér 1, 4032 Debrecen, Hungary
- Correspondence:
| | - Károly Antal
- Department of Zoology, Eszterházy Károly Catholic University, Eszterházy tér 1, 3300 Eger, Hungary
| | - Barnabás Gila
- Department of Molecular Biotechnology and Microbiology, Faculty of Sciences and Technology, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
- Doctoral School of Nutrition and Food Sciences, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
| | - Andrea P. Jónás
- Department of Molecular Biotechnology and Microbiology, Faculty of Sciences and Technology, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
| | - István Pócsi
- Department of Molecular Biotechnology and Microbiology, Faculty of Sciences and Technology, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
- ELRN-UD Fungal Stress Biology Research Group, Egyetem tér 1, 4032 Debrecen, Hungary
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15
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Gila BC, Antal K, Birkó Z, Keserű JS, Pócsi I, Emri T. Strategies Shaping the Transcription of Carbohydrate-Active Enzyme Genes in Aspergillus nidulans. J Fungi (Basel) 2022; 8:jof8010079. [PMID: 35050018 PMCID: PMC8780418 DOI: 10.3390/jof8010079] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Revised: 01/07/2022] [Accepted: 01/10/2022] [Indexed: 12/16/2022] Open
Abstract
Understanding the coordinated regulation of the hundreds of carbohydrate-active enzyme (CAZyme) genes occurring in the genomes of fungi has great practical importance. We recorded genome-wide transcriptional changes of Aspergillus nidulans cultivated on glucose, lactose, or arabinogalactan, as well as under carbon-starved conditions. We determined both carbon-stress-specific changes (weak or no carbon source vs. glucose) and carbon-source-specific changes (one type of culture vs. all other cultures). Many CAZyme genes showed carbon-stress-specific and/or carbon-source-specific upregulation on arabinogalactan (138 and 62 genes, respectively). Besides galactosidase and arabinan-degrading enzyme genes, enrichment of cellulolytic, pectinolytic, mannan, and xylan-degrading enzyme genes was observed. Fewer upregulated genes, 81 and 107 carbon stress specific, and 6 and 16 carbon source specific, were found on lactose and in carbon-starved cultures, respectively. They were enriched only in galactosidase and xylosidase genes on lactose and rhamnogalacturonanase genes in both cultures. Some CAZyme genes (29 genes) showed carbon-source-specific upregulation on glucose, and they were enriched in β-1,4-glucanase genes. The behavioral ecological background of these characteristics was evaluated to comprehensively organize our knowledge on CAZyme production, which can lead to developing new strategies to produce enzymes for plant cell wall saccharification.
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Affiliation(s)
- Barnabás Cs. Gila
- Department of Molecular Biotechnology and Microbiology, Faculty of Sciences and Technology, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary; (B.C.G.); (I.P.)
- Doctoral School of Nutrition and Food Sciences, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
| | - Károly Antal
- Department of Zoology, Eszterházy Károly Catholic University, Eszterházy tér 1, 3300 Eger, Hungary;
| | - Zsuzsanna Birkó
- Department of Human Genetics, Faculty of Medicine, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary; (Z.B.); (J.S.K.)
| | - Judit Sz. Keserű
- Department of Human Genetics, Faculty of Medicine, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary; (Z.B.); (J.S.K.)
| | - István Pócsi
- Department of Molecular Biotechnology and Microbiology, Faculty of Sciences and Technology, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary; (B.C.G.); (I.P.)
| | - Tamás Emri
- Department of Molecular Biotechnology and Microbiology, Faculty of Sciences and Technology, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary; (B.C.G.); (I.P.)
- Correspondence:
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16
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Yaakoub H, Sanchez NS, Ongay-Larios L, Courdavault V, Calenda A, Bouchara JP, Coria R, Papon N. The high osmolarity glycerol (HOG) pathway in fungi †. Crit Rev Microbiol 2021; 48:657-695. [PMID: 34893006 DOI: 10.1080/1040841x.2021.2011834] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
While fungi are widely occupying nature, many species are responsible for devastating mycosis in humans. Such niche diversity explains how quick fungal adaptation is necessary to endow the capacity of withstanding fluctuating environments and to cope with host-imposed conditions. Among all the molecular mechanisms evolved by fungi, the most studied one is the activation of the phosphorelay signalling pathways, of which the high osmolarity glycerol (HOG) pathway constitutes one of the key molecular apparatus underpinning fungal adaptation and virulence. In this review, we summarize the seminal knowledge of the HOG pathway with its more recent developments. We specifically described the HOG-mediated stress adaptation, with a particular focus on osmotic and oxidative stress, and point out some lags in our understanding of its involvement in the virulence of pathogenic species including, the medically important fungi Candida albicans, Cryptococcus neoformans, and Aspergillus fumigatus, compared to the model yeast Saccharomyces cerevisiae. Finally, we also highlighted some possible applications of the HOG pathway modifications to improve the fungal-based production of natural products in the industry.
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Affiliation(s)
- Hajar Yaakoub
- Univ Angers, Univ Brest, GEIHP, SFR ICAT, Angers, France
| | - Norma Silvia Sanchez
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City, Mexico
| | - Laura Ongay-Larios
- Unidad de Biología Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Vincent Courdavault
- EA2106 "Biomolécules et Biotechnologies Végétales", Université de Tours, Tours, France
| | | | | | - Roberto Coria
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City, Mexico
| | - Nicolas Papon
- Univ Angers, Univ Brest, GEIHP, SFR ICAT, Angers, France
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17
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Castano-Duque L, Gilbert MK, Mack BM, Lebar MD, Carter-Wientjes CH, Sickler CM, Cary JW, Rajasekaran K. Flavonoids Modulate the Accumulation of Toxins From Aspergillus flavus in Maize Kernels. FRONTIERS IN PLANT SCIENCE 2021; 12:761446. [PMID: 34899785 PMCID: PMC8662736 DOI: 10.3389/fpls.2021.761446] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 10/15/2021] [Indexed: 06/14/2023]
Abstract
Aspergillus flavus is an opportunistic fungal pathogen capable of producing aflatoxins, potent carcinogenic toxins that accumulate in maize kernels after infection. To better understand the molecular mechanisms of maize resistance to A. flavus growth and aflatoxin accumulation, we performed a high-throughput transcriptomic study in situ using maize kernels infected with A. flavus strain 3357. Three maize lines were evaluated: aflatoxin-contamination resistant line TZAR102, semi-resistant MI82, and susceptible line Va35. A modified genotype-environment association method (GEA) used to detect loci under selection via redundancy analysis (RDA) was used with the transcriptomic data to detect genes significantly influenced by maize line, fungal treatment, and duration of infection. Gene ontology enrichment analysis of genes highly expressed in infected kernels identified molecular pathways associated with defense responses to fungi and other microbes such as production of pathogenesis-related (PR) proteins and lipid bilayer formation. To further identify novel genes of interest, we incorporated genomic and phenotypic field data from a genome wide association analysis with gene expression data, allowing us to detect significantly expressed quantitative trait loci (eQTL). These results identified significant association between flavonoid biosynthetic pathway genes and infection by A. flavus. In planta fungal infections showed that the resistant line, TZAR102, has a higher fold increase of the metabolites naringenin and luteolin than the susceptible line, Va35, when comparing untreated and fungal infected plants. These results suggest flavonoids contribute to plant resistance mechanisms against aflatoxin contamination through modulation of toxin accumulation in maize kernels.
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18
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Mead ME, Steenwyk JL, Silva LP, de Castro PA, Saeed N, Hillmann F, Goldman GH, Rokas A. An evolutionary genomic approach reveals both conserved and species-specific genetic elements related to human disease in closely related Aspergillus fungi. Genetics 2021; 218:6263860. [PMID: 33944921 DOI: 10.1093/genetics/iyab066] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 04/20/2021] [Indexed: 11/12/2022] Open
Abstract
Aspergillosis is an important opportunistic human disease caused by filamentous fungi in the genus Aspergillus. Roughly 70% of infections are caused by Aspergillus fumigatus, with the rest stemming from approximately a dozen other Aspergillus species. Several of these pathogens are closely related to A. fumigatus and belong in the same taxonomic section, section Fumigati. Pathogenic species are frequently most closely related to nonpathogenic ones, suggesting Aspergillus pathogenicity evolved multiple times independently. To understand the repeated evolution of Aspergillus pathogenicity, we performed comparative genomic analyses on 18 strains from 13 species, including 8 species in section Fumigati, which aimed to identify genes, both ones previously connected to virulence as well as ones never before implicated, whose evolution differs between pathogens and nonpathogens. We found that most genes were present in all species, including approximately half of those previously connected to virulence, but a few genes were section- or species-specific. Evolutionary rate analyses identified over 1700 genes whose evolutionary rate differed between pathogens and nonpathogens and dozens of genes whose rates differed between specific pathogens and the rest of the taxa. Functional testing of deletion mutants of 17 transcription factor-encoding genes whose evolution differed between pathogens and nonpathogens identified eight genes that affect either fungal survival in a model of phagocytic killing, host survival in an animal model of fungal disease, or both. These results suggest that the evolution of pathogenicity in Aspergillus involved both conserved and species-specific genetic elements, illustrating how an evolutionary genomic approach informs the study of fungal disease.
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Affiliation(s)
- Matthew E Mead
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA
| | - Jacob L Steenwyk
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA
| | - Lilian P Silva
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Patrícia A de Castro
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Nauman Saeed
- Junior Research Group Evolution of Microbial Interactions, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute (HKI), Jena, Germany
| | - Falk Hillmann
- Junior Research Group Evolution of Microbial Interactions, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute (HKI), Jena, Germany
| | - Gustavo H Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Antonis Rokas
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA
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19
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Gao J, Xu X, Huang K, Liang Z. Fungal G-Protein-Coupled Receptors: A Promising Mediator of the Impact of Extracellular Signals on Biosynthesis of Ochratoxin A. Front Microbiol 2021; 12:631392. [PMID: 33643259 PMCID: PMC7907439 DOI: 10.3389/fmicb.2021.631392] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 01/21/2021] [Indexed: 01/17/2023] Open
Abstract
G-protein-coupled receptors (GPCRs) are transmembrane receptors involved in transducing signals from the external environment inside the cell, which enables fungi to coordinate cell transport, metabolism, and growth to promote their survival, reproduction, and virulence. There are 14 classes of GPCRs in fungi involved in sensing various ligands. In this paper, the synthesis of mycotoxins that are GPCR-mediated is discussed with respect to ligands, environmental stimuli, and intra-/interspecific communication. Despite their apparent importance in fungal biology, very little is known about the role of ochratoxin A (OTA) biosynthesis by Aspergillus ochraceus and the ligands that are involved. Fortunately, increasing evidence shows that the GPCR that involves the AF/ST (sterigmatocystin) pathway in fungi belongs to the same genus. Therefore, we speculate that GPCRs play an important role in a variety of environmental signals and downstream pathways in OTA biosynthesis. The verification of this inference will result in a more controllable GPCR target for control of fungal contamination in the future.
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Affiliation(s)
- Jing Gao
- Beijing Laboratory for Food Quality and Safety, Beijing, China
| | - Xinge Xu
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Kunlun Huang
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Zhihong Liang
- Beijing Laboratory for Food Quality and Safety, Beijing, China.,College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
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20
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Abstract
The fungal zinc finger transcription factor NsdC is named after, and is best known for, its essential role in sexual reproduction (never in sexual development). In previous studies with Aspergillus nidulans, it was also shown to have roles in promotion of vegetative growth and suppression of asexual conidiation. In this study, the function of the nsdC homologue in the opportunistic human pathogen A. fumigatus was investigated. NsdC was again found to be essential for sexual development, with deletion of the nsdC gene in both MAT1-1 and MAT1-2 mating partners of a cross leading to complete loss of fertility. However, a functional copy of nsdC in one mating partner was sufficient to allow sexual reproduction. Deletion of nsdC also led to decreased vegetative growth and allowed conidiation in liquid cultures, again consistent with previous findings. However, NsdC in A. fumigatus was shown to have additional biological functions including response to calcium stress, correct organization of cell wall structure, and response to the cell wall stressors. Furthermore, virulence and host immune recognition were affected. Gene expression studies involving chromatin immunoprecipitation (ChIP) of RNA polymerase II (PolII) coupled to next-generation sequencing (Seq) revealed that deletion of nsdC resulted in changes in expression of over 620 genes under basal growth conditions. This demonstrated that this transcription factor mediates the activity of a wide variety of signaling and metabolic pathways and indicates that despite the naming of the gene, the promotion of sexual reproduction is just one among multiple roles of NsdC.IMPORTANCE Aspergillus fumigatus is an opportunistic human fungal pathogen and the main causal agent of invasive aspergillosis, a life-threatening infection especially in immunocompromised patients. A. fumigatus can undergo both asexual and sexual reproductive cycles, and the regulation of both cycles involves several genes and pathways. Here, we have characterized one of these genetic determinants, the NsdC transcription factor, which was initially identified in a screen of transcription factor null mutants showing sensitivity when exposed to high concentrations of calcium. In addition to its known essential roles in sexual reproduction and control of growth rate and asexual reproduction, we have shown in the present study that A. fumigatus NsdC transcription factor has additional previously unrecognized biological functions including calcium tolerance, cell wall stress response, and correct cell wall organization and functions in virulence and host immune recognition. Our results indicate that NsdC can play novel additional biological functions not directly related to its role played during sexual and asexual processes.
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21
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Aspergillus fumigatus G-Protein Coupled Receptors GprM and GprJ Are Important for the Regulation of the Cell Wall Integrity Pathway, Secondary Metabolite Production, and Virulence. mBio 2020; 11:mBio.02458-20. [PMID: 33051372 PMCID: PMC7554674 DOI: 10.1128/mbio.02458-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
A. fumigatus is the main etiological agent of invasive pulmonary aspergillosis, a life-threatening fungal disease that occurs in severely immunocompromised humans. Withstanding the host environment is essential for A. fumigatus virulence, and sensing of extracellular cues occurs primarily through G-protein coupled receptors (GPCRs) that activate signal transduction pathways, which, in turn, regulate fungal development, metabolism, virulence, and mycotoxin biosynthesis. The A. fumigatus genome encodes 15 putative classical GPCRs, with only three having been functionally characterized to date. In this work, we show that the two GPCRs GprM and GprJ regulate the phosphorylation of the mitogen-activated protein kinase MpkA and thus control the regulation of the cell wall integrity pathway. GprM and GprJ are also involved in the regulation of the production of the secondary metabolites fumagillin, pyripyropene, fumigaclavine C, fumiquinazoline, melanin, and fumitremorgin, and this regulation partially occurs through the activation of MpkA. Furthermore, GprM and GprJ are important for virulence in the insect model Galleria mellonella. This work therefore functionally characterizes two GPCRs and shows how they regulate several intracellular pathways that have been shown to be crucial for A. fumigatus virulence. G-protein coupled receptors (GPCRs) are extracellular signaling receptors that sense environmental cues. Fungi sense their environment primarily through GPCR-mediated signaling pathways, which, in turn, regulate fungal development, metabolism, virulence, and mycotoxin biosynthesis. Aspergillus fumigatus is an important human pathogen that causes aspergillosis, a heterogeneous group of diseases that present a wide range of clinical manifestations. Here, we investigate in detail the role of the GPCRs GprM and GprJ in growth and gene expression. GprM and GprJ are important for melanin production and the regulation of the cell wall integrity (CWI) pathway. Overexpression of gprM and gprJ causes a 20 and 50% reduction in growth rate compared to the wild-type (WT) strain and increases sensitivity to cell wall-damaging agents. Phosphorylation of the CWI protein kinase MpkA is increased in the ΔgprM and ΔgprJ strains and decreased in the overexpression mutants compared to the WT strain. Furthermore, differences in cell wall polysaccharide concentrations and organization were observed in these strains. Transcriptome sequencing suggests that GprM and GprJ negatively regulate genes encoding secondary metabolites (SMs). Mass spectrometry analysis confirmed that the production of fumagillin, pyripyropene, fumigaclavine C, fumiquinazoline, and fumitremorgin is reduced in the ΔgprM and ΔgprJ strains, at least partially through the activation of MpkA. Overexpression of grpM also resulted in the regulation of many transcription factors, with AsgA predicted to function downstream of GprM and MpkA signaling. Finally, we show that the ΔgprM and ΔgprJ mutants are reduced in virulence in the Galleria mellonella insect model of invasive aspergillosis.
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Putative Membrane Receptors Contribute to Activation and Efficient Signaling of Mitogen-Activated Protein Kinase Cascades during Adaptation of Aspergillus fumigatus to Different Stressors and Carbon Sources. mSphere 2020; 5:5/5/e00818-20. [PMID: 32938702 PMCID: PMC7494837 DOI: 10.1128/msphere.00818-20] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The high-osmolarity glycerol (HOG) response pathway is a multifunctional signal transduction pathway that specifically transmits ambient osmotic signals. Saccharomyces cerevisiae Hog1p has two upstream signaling branches, the sensor histidine kinase Sln1p and the receptor Sho1p. The Sho1p branch includes two other proteins, the Msb2p mucin and Opy2p. Aspergillus fumigatus is the leading cause of pulmonary fungal diseases. Here, we investigated the roles played by A. fumigatus SlnASln1p, ShoASho1p, MsbAMsb2p, and OpyAOpy2p putative homologues during the activation of the mitogen-activated protein kinase (MAPK) HOG pathway. The shoA, msbA, and opyA singly and doubly null mutants are important for the cell wall integrity (CWI) pathway, oxidative stress, and virulence as assessed by a Galleria mellonella model. Genetic interactions of ShoA, MsbA, and OpyA are also important for proper activation of the SakAHog1p and MpkASlt2 cascade and the response to osmotic and cell wall stresses. Comparative label-free quantitative proteomics analysis of the singly null mutants with the wild-type strain upon caspofungin exposure indicates that the absence of ShoA, MsbA, and OpyA affects the osmotic stress response, carbohydrate metabolism, and protein degradation. The putative receptor mutants showed altered trehalose and glycogen accumulation, suggesting a role for ShoA, MsbA, and OpyA in sugar storage. Protein kinase A activity was also decreased in these mutants. We also observed genetic interactions between SlnA, ShoA, MsbA, and OpyA, suggesting that both branches are important for activation of the HOG/CWI pathways. Our results help in the understanding of the activation and modulation of the HOG and CWI pathways in this important fungal pathogen.IMPORTANCE Aspergillus fumigatus is an important human-pathogenic fungal species that is responsible for a high incidence of infections in immunocompromised individuals. A. fumigatus high-osmolarity glycerol (HOG) and cell wall integrity pathways are important for the adaptation to different forms of environmental adversity such as osmotic and oxidative stresses, nutrient limitations, high temperatures, and other chemical and mechanical stresses that may be produced by the host immune system and antifungal drugs. Little is known about how these pathways are activated in this fungal pathogen. Here, we characterize four A. fumigatus putative homologues that are important for the activation of the yeast HOG pathway. A. fumigatus SlnASln1p, ShoASho1p, MsbAMsb2p, and OpyAOpy2p are genetically interacting and are essential for the activation of the HOG and cell wall integrity pathways. Our results contribute to the understanding of A. fumigatus adaptation to the host environment.
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Steenwyk JL, Lind AL, Ries LNA, Dos Reis TF, Silva LP, Almeida F, Bastos RW, Fraga da Silva TFDC, Bonato VLD, Pessoni AM, Rodrigues F, Raja HA, Knowles SL, Oberlies NH, Lagrou K, Goldman GH, Rokas A. Pathogenic Allodiploid Hybrids of Aspergillus Fungi. Curr Biol 2020; 30:2495-2507.e7. [PMID: 32502407 PMCID: PMC7343619 DOI: 10.1016/j.cub.2020.04.071] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 02/25/2020] [Accepted: 04/24/2020] [Indexed: 12/12/2022]
Abstract
Interspecific hybridization substantially alters genotypes and phenotypes and can give rise to new lineages. Hybrid isolates that differ from their parental species in infection-relevant traits have been observed in several human-pathogenic yeasts and plant-pathogenic filamentous fungi but have yet to be found in human-pathogenic filamentous fungi. We discovered 6 clinical isolates from patients with aspergillosis originally identified as Aspergillus nidulans (section Nidulantes) that are actually allodiploid hybrids formed by the fusion of Aspergillus spinulosporus with an unknown close relative of Aspergillus quadrilineatus, both in section Nidulantes. Evolutionary genomic analyses revealed that these isolates belong to Aspergillus latus, an allodiploid hybrid species. Characterization of diverse infection-relevant traits further showed that A. latus hybrid isolates are genomically and phenotypically heterogeneous but also differ from A. nidulans, A. spinulosporus, and A. quadrilineatus. These results suggest that allodiploid hybridization contributes to the genomic and phenotypic diversity of filamentous fungal pathogens of humans.
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Affiliation(s)
- Jacob L Steenwyk
- Department of Biological Sciences, Vanderbilt University, 465 21st Avenue South, Nashville, TN 37235, USA
| | - Abigail L Lind
- Department of Biomedical Informatics, Vanderbilt University School of Medicine, 1211 Medical Center Drive, Nashville, TN 37232, USA; Gladstone Institute of Data Science and Biotechnology, San Francisco, CA 94158, USA
| | - Laure N A Ries
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (FMRP-USP), Avenida Bandeirantes 3900, Vila Monte Alegre, 14049-900 Ribeirão Preto, São Paulo, Brazil; Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Departamento de Ciências Farmacêuticas, Universidade de São Paulo, Avenida do Café S/N, Ribeirão Preto 14040-903, Brazil
| | - Thaila F Dos Reis
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (FMRP-USP), Avenida Bandeirantes 3900, Vila Monte Alegre, 14049-900 Ribeirão Preto, São Paulo, Brazil; Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Departamento de Ciências Farmacêuticas, Universidade de São Paulo, Avenida do Café S/N, Ribeirão Preto 14040-903, Brazil
| | - Lilian P Silva
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Departamento de Ciências Farmacêuticas, Universidade de São Paulo, Avenida do Café S/N, Ribeirão Preto 14040-903, Brazil
| | - Fausto Almeida
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (FMRP-USP), Avenida Bandeirantes 3900, Vila Monte Alegre, 14049-900 Ribeirão Preto, São Paulo, Brazil
| | - Rafael W Bastos
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Departamento de Ciências Farmacêuticas, Universidade de São Paulo, Avenida do Café S/N, Ribeirão Preto 14040-903, Brazil
| | - Thais Fernanda de Campos Fraga da Silva
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (FMRP-USP), Avenida Bandeirantes 3900, Vila Monte Alegre, 14049-900 Ribeirão Preto, São Paulo, Brazil
| | - Vania L D Bonato
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (FMRP-USP), Avenida Bandeirantes 3900, Vila Monte Alegre, 14049-900 Ribeirão Preto, São Paulo, Brazil
| | - André Moreira Pessoni
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (FMRP-USP), Avenida Bandeirantes 3900, Vila Monte Alegre, 14049-900 Ribeirão Preto, São Paulo, Brazil
| | - Fernando Rodrigues
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4715-495 Braga, Portugal; ICVS/3B's-PT Government Associate Laboratory, 4715-495 Braga, Portugal
| | - Huzefa A Raja
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, 1400 Spring Garden Street, Greensboro, NC 27412, USA
| | - Sonja L Knowles
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, 1400 Spring Garden Street, Greensboro, NC 27412, USA
| | - Nicholas H Oberlies
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, 1400 Spring Garden Street, Greensboro, NC 27412, USA
| | - Katrien Lagrou
- Department of Microbiology, Immunology and Transplantation, Katholieke Universiteit Leuven, 3000 Leuven, Belgium; Department of Laboratory Medicine and National Reference Centre for Mycosis, University Hospitals Leuven, 3000 Leuven, Belgium
| | - Gustavo H Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Departamento de Ciências Farmacêuticas, Universidade de São Paulo, Avenida do Café S/N, Ribeirão Preto 14040-903, Brazil.
| | - Antonis Rokas
- Department of Biological Sciences, Vanderbilt University, 465 21st Avenue South, Nashville, TN 37235, USA; Department of Biomedical Informatics, Vanderbilt University School of Medicine, 1211 Medical Center Drive, Nashville, TN 37232, USA.
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Binder J, Shadkchan Y, Osherov N, Krappmann S. The Essential Thioredoxin Reductase of the Human Pathogenic Mold Aspergillus fumigatus Is a Promising Antifungal Target. Front Microbiol 2020; 11:1383. [PMID: 32670238 PMCID: PMC7330004 DOI: 10.3389/fmicb.2020.01383] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Accepted: 05/28/2020] [Indexed: 12/12/2022] Open
Abstract
The identification of cellular targets for antifungal compounds is a cornerstone for the development of novel antimycotics, for which a significant need exists due to increasing numbers of susceptible patients, emerging pathogens, and evolving resistance. For the human pathogenic mold Aspergillus fumigatus, the causative agent of the opportunistic disease aspergillosis, only a limited number of established targets and corresponding drugs are available. Among several targets that were postulated from a variety of experimental approaches, the conserved thioredoxin reductase (TrxR) activity encoded by the trxR gene was assessed in this study. Its essentiality could be confirmed following a conditional TetOFF promoter replacement strategy. Relevance of the trxR gene product for oxidative stress resistance was revealed and, most importantly, its requirement for full virulence of A. fumigatus in two different models of infection resembling invasive aspergillosis. Our findings complement the idea of targeting the reductase component of the fungal thioredoxin system for antifungal therapy.
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Affiliation(s)
- Jasmin Binder
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen and Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Yana Shadkchan
- Aspergillus and Antifungal Research Laboratory, Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv-Yafo, Israel
| | - Nir Osherov
- Aspergillus and Antifungal Research Laboratory, Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv-Yafo, Israel
| | - Sven Krappmann
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen and Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.,Medical Immunology Campus Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.,Erlangen Center of Infection Research, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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Rokas A, Mead ME, Steenwyk JL, Oberlies NH, Goldman GH. Evolving moldy murderers: Aspergillus section Fumigati as a model for studying the repeated evolution of fungal pathogenicity. PLoS Pathog 2020; 16:e1008315. [PMID: 32106242 PMCID: PMC7046185 DOI: 10.1371/journal.ppat.1008315] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Antonis Rokas
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
- * E-mail:
| | - Matthew E. Mead
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Jacob L. Steenwyk
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Nicholas H. Oberlies
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, North Carolina, United States of America
| | - Gustavo H. Goldman
- Faculdade de Ciencias Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
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de Castro PA, Colabardini AC, Manfiolli AO, Chiaratto J, Silva LP, Mattos EC, Palmisano G, Almeida F, Persinoti GF, Ries LNA, Mellado L, Rocha MC, Bromley M, Silva RN, de Souza GS, Loures FV, Malavazi I, Brown NA, Goldman GH. Aspergillus fumigatus calcium-responsive transcription factors regulate cell wall architecture promoting stress tolerance, virulence and caspofungin resistance. PLoS Genet 2019; 15:e1008551. [PMID: 31887136 PMCID: PMC6948819 DOI: 10.1371/journal.pgen.1008551] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 01/08/2020] [Accepted: 12/02/2019] [Indexed: 11/28/2022] Open
Abstract
Aspergillus fumigatus causes invasive aspergillosis, the most common life-threatening fungal disease of immuno-compromised humans. The treatment of disseminated infections with antifungal drugs, including echinocandin cell wall biosynthesis inhibitors, is increasingly challenging due to the rise of drug-resistant pathogens. The fungal calcium responsive calcineurin-CrzA pathway influences cell morphology, cell wall composition, virulence, and echinocandin resistance. A screen of 395 A. fumigatus transcription factor mutants identified nine transcription factors important to calcium stress tolerance, including CrzA and ZipD. Here, comparative transcriptomics revealed CrzA and ZipD regulated the expression of shared and unique gene networks, suggesting they participate in both converged and distinct stress response mechanisms. CrzA and ZipD additively promoted calcium stress tolerance. However, ZipD also regulated cell wall organization, osmotic stress tolerance and echinocandin resistance. The absence of ZipD in A. fumigatus caused a significant virulence reduction in immunodeficient and immunocompetent mice. The ΔzipD mutant displayed altered cell wall organization and composition, while being more susceptible to macrophage killing and eliciting an increased pro-inflammatory cytokine response. A higher number of neutrophils, macrophages and activated macrophages were found in ΔzipD infected mice lungs. Collectively, this shows that ZipD-mediated regulation of the fungal cell wall contributes to the evasion of pro-inflammatory responses and tolerance of echinocandin antifungals, and in turn promoting virulence and complicating treatment options.
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Affiliation(s)
- Patrícia Alves de Castro
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Ana Cristina Colabardini
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Adriana Oliveira Manfiolli
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Jéssica Chiaratto
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Lilian Pereira Silva
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Eliciane Cevolani Mattos
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Giuseppe Palmisano
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Fausto Almeida
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Gabriela Felix Persinoti
- Laboratório Nacional de Biorrenováveis (LNBR), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas, São Paulo, Brasil
| | - Laure Nicolas Annick Ries
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Laura Mellado
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Marina Campos Rocha
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | - Michael Bromley
- Manchester Fungal Infection Group, Institute of Inflammation and Repair, University of Manchester, Manchester, United Kingdom
| | - Roberto Nascimento Silva
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Gabriel Scalini de Souza
- Instituto de Ciência e Tecnologia, Universidade Federal de São Paulo, São José dos Campos, Brazil
| | - Flávio Vieira Loures
- Instituto de Ciência e Tecnologia, Universidade Federal de São Paulo, São José dos Campos, Brazil
| | - Iran Malavazi
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | - Neil Andrew Brown
- Department of Biology & Biochemistry, University of Bath, Claverton Down, Bath, United Kingdom
| | - Gustavo H Goldman
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
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Denham ST, Wambaugh MA, Brown JCS. How Environmental Fungi Cause a Range of Clinical Outcomes in Susceptible Hosts. J Mol Biol 2019; 431:2982-3009. [PMID: 31078554 PMCID: PMC6646061 DOI: 10.1016/j.jmb.2019.05.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 04/18/2019] [Accepted: 05/01/2019] [Indexed: 12/11/2022]
Abstract
Environmental fungi are globally ubiquitous and human exposure is near universal. However, relatively few fungal species are capable of infecting humans, and among fungi, few exposure events lead to severe systemic infections. Systemic infections have mortality rates of up to 90%, cost the US healthcare system $7.2 billion annually, and are typically associated with immunocompromised patients. Despite this reputation, exposure to environmental fungi results in a range of outcomes, from asymptomatic latent infections to severe systemic infection. Here we discuss different exposure outcomes for five major fungal pathogens: Aspergillus, Blastomyces, Coccidioides, Cryptococcus, and Histoplasma species. These fungi include a mold, a budding yeast, and thermal dimorphic fungi. All of these species must adapt to dramatically changing environments over the course of disease. These dynamic environments include the human lung, which is the first exposure site for these organisms. Fungi must defend themselves against host immune cells while germinating and growing, which risks further exposing microbe-associated molecular patterns to the host. We discuss immune evasion strategies during early infection, from disruption of host immune cells to major changes in fungal cell morphology.
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Affiliation(s)
- Steven T Denham
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
| | - Morgan A Wambaugh
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
| | - Jessica C S Brown
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, UT 84132, USA.
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Manfiolli AO, Mattos EC, de Assis LJ, Silva LP, Ulaş M, Brown NA, Silva-Rocha R, Bayram Ö, Goldman GH. Aspergillus fumigatus High Osmolarity Glycerol Mitogen Activated Protein Kinases SakA and MpkC Physically Interact During Osmotic and Cell Wall Stresses. Front Microbiol 2019; 10:918. [PMID: 31134001 PMCID: PMC6514138 DOI: 10.3389/fmicb.2019.00918] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 04/11/2019] [Indexed: 11/30/2022] Open
Abstract
Aspergillusfumigatus, a saprophytic filamentous fungus, is a serious opportunistic pathogen of mammals and it is the primary causal agent of invasive aspergillosis (IA). Mitogen activated protein Kinases (MAPKs) are important components involved in diverse cellular processes in eukaryotes. A. fumigatus MpkC and SakA, the homologs of the Saccharomyces cerevisiae Hog1 are important to adaptations to oxidative and osmotic stresses, heat shock, cell wall damage, macrophage recognition, and full virulence. We performed protein pull-down experiments aiming to identify interaction partners of SakA and MpkC by mass spectrometry analysis. In presence of osmotic stress with sorbitol, 118, and 213 proteins were detected as possible protein interactors of SakA and MpkC, respectively. Under cell wall stress caused by congo red, 420 and 299 proteins were detected interacting with SakA and MpkC, respectively. Interestingly, a group of 78 and 256 proteins were common to both interactome analysis. Co-immunoprecipitation (Co-IP) experiments showed that SakA::GFP is physically associated with MpkC:3xHA upon osmotic and cell wall stresses. We also validated the association between SakA:GFP and the cell wall integrity MAPK MpkA:3xHA and the phosphatase PtcB:3xHA, under cell wall stress. We further characterized A. fumigatus PakA, the homolog of the S. cerevisiae sexual developmental serine/threonine kinase Ste20, as a component of the SakA/MpkC MAPK pathway. The ΔpakA strain is more sensitive to cell wall damaging agents as congo red, calcofluor white, and caspofungin. Together, our data supporting the hypothesis that SakA and MpkC are part of an osmotic and general signal pathways involved in regulation of the response to the cell wall damage, oxidative stress, drug resistance, and establishment of infection. This manuscript describes an important biological resource to understand SakA and MpkC protein interactions. Further investigation of the biological roles played by these protein interactors will provide more opportunities to understand and combat IA.
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Affiliation(s)
- Adriana Oliveira Manfiolli
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Eliciane Cevolani Mattos
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Leandro José de Assis
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Lilian Pereira Silva
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Mevlüt Ulaş
- Department of Biology, Maynooth University, Maynooth, Ireland
| | - Neil Andrew Brown
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Rafael Silva-Rocha
- Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Özgür Bayram
- Department of Biology, Maynooth University, Maynooth, Ireland
| | - Gustavo H Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
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Ouyang H, Du T, Zhou H, Wilson IBH, Yang J, Latgé JP, Jin C. Aspergillus fumigatus phosphoethanolamine transferase gene gpi7 is required for proper transportation of the cell wall GPI-anchored proteins and polarized growth. Sci Rep 2019; 9:5857. [PMID: 30971734 PMCID: PMC6458175 DOI: 10.1038/s41598-019-42344-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 02/21/2019] [Indexed: 01/10/2023] Open
Abstract
In fungi many proteins, which play important roles in maintaining the function of the cell wall and participating in pathogenic processes, are anchored to the cell surface by a glycosylphosphatidylinositol (GPI) anchor. It has been known that modification and removal of phosphoethanolamine (EtN-P) on the second mannose residue in GPI anchors is important for maturation and sorting of GPI anchored proteins in yeast and mammalian cells, but is a step absent from some protist parasites. In Aspergillus fumigatus, an opportunistic fungal pathogen causing invasive aspergillosis in humans, GPI-anchored proteins are known to be involved in cell wall synthesis and virulence. In this report the gene encoding A. fumigatus EtN-P transferase GPI7 was investigated. By deletion of the gpi7 gene, we evaluated the effects of EtN-P modification on the morphogenesis of A. fumigatus and localization of GPI proteins. Our results showed that deletion of the gpi7 gene led to reduced cell membrane GPI anchored proteins, the mis-localization of the cell wall GPI anchored protein Mp1, abnormal polarity, and autophagy in A. fumigatus. Our results suggest that addition of EtN-P of the second mannose on the GPI anchor is essential for transportation and localization of the cell wall GPI-anchored proteins.
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Affiliation(s)
- Haomiao Ouyang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Ting Du
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Hui Zhou
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Iain B H Wilson
- Department of Chemistry, University of Natural Resources and Life Sciences, Vienna, A-1190, Austria
| | - Jinghua Yang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Jean-Paul Latgé
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Cheng Jin
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China. .,Guangxi Academy of Sciences, Nanning, 530007, Guangxi, China.
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Hagiwara D, Takahashi H, Takagi H, Watanabe A, Kamei K. Heterogeneity in Pathogenicity-related Properties and Stress Tolerance in Aspergillus fumigatus Clinical Isolates. Med Mycol J 2019; 59:E63-E70. [PMID: 30504617 DOI: 10.3314/mmj.18-00007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Stress responses and pathogenicity have been extensively studied in Aspergillus fumigatus, the main causative pathogen of life-threatening aspergillosis. The heterogeneity in this pathogen's biology has recently attracted increasing attention. In the present work, we used 16 clinically isolated strains to investigate several properties relevant to the pathogenicity of A. fumigatus, namely, gliotoxin production, elastase activity, hypoxia growth, adaptation to iron-limiting conditions, and growth upon nitrosative, oxidative, and high osmotic stresses. The range of phenotypes was diverse across the strains, with gliotoxin production and elastase activity being negatively correlated at an intermediate index (R=-0.4717). Notably, there were strains that showed extraordinary high production of gliotoxin or elastase activity and hypersensitivity to nitrosative or oxidative stresses. Clustering analysis showed that the 7 potentially pathogenicity-related phenotypes were not correlated with the genetic sub-group or pathotype. These results contribute to the growing awareness of the genetic and phenotypic diversity in A. fumigatus isolates.
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Affiliation(s)
- Daisuke Hagiwara
- Medical Mycology Research Center, Chiba University.,Faculty of Life and Environmental Sciences, University of Tsukuba
| | - Hiroki Takahashi
- Medical Mycology Research Center, Chiba University.,Molecular Chirality Research Center, Chiba University
| | - Hiroshi Takagi
- Graduate School of Science and Technology, Nara Institute of Science and Technology
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Mead ME, Knowles SL, Raja HA, Beattie SR, Kowalski CH, Steenwyk JL, Silva LP, Chiaratto J, Ries LNA, Goldman GH, Cramer RA, Oberlies NH, Rokas A. Characterizing the Pathogenic, Genomic, and Chemical Traits of Aspergillus fischeri, a Close Relative of the Major Human Fungal Pathogen Aspergillus fumigatus. mSphere 2019; 4:e00018-19. [PMID: 30787113 PMCID: PMC6382966 DOI: 10.1128/msphere.00018-19] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 02/04/2019] [Indexed: 12/15/2022] Open
Abstract
Aspergillus fischeri is closely related to Aspergillus fumigatus, the major cause of invasive mold infections. Even though A. fischeri is commonly found in diverse environments, including hospitals, it rarely causes invasive disease. Why A. fischeri causes less human disease than A. fumigatus is unclear. A comparison of A. fischeri and A. fumigatus for pathogenic, genomic, and secondary metabolic traits revealed multiple differences in pathogenesis-related phenotypes. We observed that A. fischeri NRRL 181 is less virulent than A. fumigatus strain CEA10 in multiple animal models of disease, grows slower in low-oxygen environments, and is more sensitive to oxidative stress. Strikingly, the observed differences for some traits are of the same order of magnitude as those previously reported between A. fumigatus strains. In contrast, similar to what has previously been reported, the two species exhibit high genomic similarity; ∼90% of the A. fumigatus proteome is conserved in A. fischeri, including 48/49 genes known to be involved in A. fumigatus virulence. However, only 10/33 A. fumigatus biosynthetic gene clusters (BGCs) likely involved in secondary metabolite production are conserved in A. fischeri and only 13/48 A. fischeri BGCs are conserved in A. fumigatus Detailed chemical characterization of A. fischeri cultures grown on multiple substrates identified multiple secondary metabolites, including two new compounds and one never before isolated as a natural product. Additionally, an A. fischeri deletion mutant of laeA, a master regulator of secondary metabolism, produced fewer secondary metabolites and in lower quantities, suggesting that regulation of secondary metabolism is at least partially conserved. These results suggest that the nonpathogenic A. fischeri possesses many of the genes important for A. fumigatus pathogenicity but is divergent with respect to its ability to thrive under host-relevant conditions and its secondary metabolism.IMPORTANCEAspergillus fumigatus is the primary cause of aspergillosis, a devastating ensemble of diseases associated with severe morbidity and mortality worldwide. A. fischeri is a close relative of A. fumigatus but is not generally observed to cause human disease. To gain insights into the underlying causes of this remarkable difference in pathogenicity, we compared two representative strains (one from each species) for a range of pathogenesis-relevant biological and chemical characteristics. We found that disease progression in multiple A. fischeri mouse models was slower and caused less mortality than A. fumigatus Remarkably, the observed differences between A. fischeri and A. fumigatus strains examined here closely resembled those previously described for two commonly studied A. fumigatus strains, AF293 and CEA10. A. fischeri and A. fumigatus exhibited different growth profiles when placed in a range of stress-inducing conditions encountered during infection, such as low levels of oxygen and the presence of chemicals that induce the production of reactive oxygen species. We also found that the vast majority of A. fumigatus genes known to be involved in virulence are conserved in A. fischeri, whereas the two species differ significantly in their secondary metabolic pathways. These similarities and differences that we report here are the first step toward understanding the evolutionary origin of a major fungal pathogen.
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Affiliation(s)
- Matthew E Mead
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Sonja L Knowles
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, North Carolina, USA
| | - Huzefa A Raja
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, North Carolina, USA
| | - Sarah R Beattie
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Caitlin H Kowalski
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Jacob L Steenwyk
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Lilian P Silva
- Faculdade de Ciencias Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Jessica Chiaratto
- Faculdade de Ciencias Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Laure N A Ries
- Faculdade de Ciencias Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Gustavo H Goldman
- Faculdade de Ciencias Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Robert A Cramer
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Nicholas H Oberlies
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, North Carolina, USA
| | - Antonis Rokas
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
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Hokken MWJ, Zoll J, Coolen JPM, Zwaan BJ, Verweij PE, Melchers WJG. Phenotypic plasticity and the evolution of azole resistance in Aspergillus fumigatus; an expression profile of clinical isolates upon exposure to itraconazole. BMC Genomics 2019; 20:28. [PMID: 30626317 PMCID: PMC6327609 DOI: 10.1186/s12864-018-5255-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 11/15/2018] [Indexed: 01/26/2023] Open
Abstract
Background The prevalence of azole resistance in clinical and environmental Aspergillus fumigatus isolates is rising over the past decades, but the molecular basis of the development of antifungal drug resistance is not well understood. This study focuses on the role of phenotypic plasticity in the evolution of azole resistance in A. fumigatus. When A. fumigatus is challenged with a new stressful environment, phenotypic plasticity may allow A. fumigatus to adjust their physiology to still enable growth and reproduction, therefore allowing the establishment of genetic adaptations through natural selection on the available variation in the mutational and recombinational gene pool. To investigate these short-term physiological adaptations, we conducted time series transcriptome analyses on three clinical A. fumigatus isolates, during incubation with itraconazole. Results After analysis of expression patterns, we identified 3955, 3430, 1207, and 1101 differentially expressed genes (DEGs), after 30, 60, 120 and 240 min of incubation with itraconazole, respectively. We explored the general functions in these gene groups and we identified 186 genes that were differentially expressed during the whole time series. Additionally, we investigated expression patterns of potential novel drug-efflux transporters, genes involved in ergosterol and phospholipid biosynthesis, and the known MAPK proteins of A. fumigatus. Conclusions Our data suggests that A. fumigatus adjusts its transcriptome quickly within 60 min of exposure to itraconazole. Further investigation of these short-term adaptive phenotypic plasticity mechanisms might enable us to understand how the direct response of A. fumigatus to itraconazole promotes survival of the fungus in the patient, before any “hard-wired” genetic mutations arise. Electronic supplementary material The online version of this article (10.1186/s12864-018-5255-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Margriet W J Hokken
- Department of Medical Microbiology, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525GA, Nijmegen, the Netherlands. .,Center of Expertise in Mycology Radboudumc/CWZ, Weg door Jonkerbos 100, 6532 SZ, Nijmegen, the Netherlands.
| | - Jan Zoll
- Department of Medical Microbiology, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525GA, Nijmegen, the Netherlands.,Center of Expertise in Mycology Radboudumc/CWZ, Weg door Jonkerbos 100, 6532 SZ, Nijmegen, the Netherlands
| | - Jordy P M Coolen
- Department of Medical Microbiology, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525GA, Nijmegen, the Netherlands.,Center of Expertise in Mycology Radboudumc/CWZ, Weg door Jonkerbos 100, 6532 SZ, Nijmegen, the Netherlands
| | - Bas J Zwaan
- Department of Plant Sciences, Laboratory of Genetics, Wageningen University, Droevendaalsesteeg 1, 6708PB, Wageningen, The Netherlands
| | - Paul E Verweij
- Department of Medical Microbiology, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525GA, Nijmegen, the Netherlands.,Center of Expertise in Mycology Radboudumc/CWZ, Weg door Jonkerbos 100, 6532 SZ, Nijmegen, the Netherlands
| | - Willem J G Melchers
- Department of Medical Microbiology, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525GA, Nijmegen, the Netherlands.,Center of Expertise in Mycology Radboudumc/CWZ, Weg door Jonkerbos 100, 6532 SZ, Nijmegen, the Netherlands
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Zhang C, Meng X, Gu H, Ma Z, Lu L. Predicted Glycerol 3-Phosphate Dehydrogenase Homologs and the Glycerol Kinase GlcA Coordinately Adapt to Various Carbon Sources and Osmotic Stress in Aspergillus fumigatus. G3 (BETHESDA, MD.) 2018; 8:2291-2299. [PMID: 29739860 PMCID: PMC6027872 DOI: 10.1534/g3.118.200253] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Accepted: 05/03/2018] [Indexed: 01/01/2023]
Abstract
Glycerol plays an important role in the adaptation of fungi to various microenvironments and stressors, including heat shock, anoxic conditions and osmotic stress. Glycerol 3-phosphate dehydrogenase (G3PDH) is able to catalyze dihydroxyacetone phosphate to glycerol 3-phosphate (G3P), which is subsequently dephosphorylated into glycerol. However, current knowledge about the functions of G3PDH homologs in glycerol biosynthesis in Aspergillus fumigatus is limited. Here, we show that the A. fumigatus G3PDH gene, gfdA, is crucial for normal colony growth in glucose media under both normoxic and hypoxic conditions. In addition, failure of the overexpression of the gfdA homolog, gfdB, to rescue the phenotype of a gfdA null mutant suggests that gfdA plays a predominant role in the synthesis of G3P and glycerol. However, in a wild-type background, overexpressing either gfdA or gfdB is able to significantly enhance biomass production of mycelia, suggesting that gfdA and gfdB have similar functions in promoting the use of glucose. Interestingly, overexpression of the gene encoding the predicted glycerol kinase, GlcA, which is capable of phosphorylating glycerol to form G3P, significantly rescues the growth defects of gfdA null mutants in glucose media, indicating that the growth defects of gfdA null mutants might be due to the absence of G3P rather than glycerol. Moreover, Western blotting analysis revealed that gfdA is inducibly expressed by osmotic mediators. However, in the absence of gfdA, osmotic stress can rescue colony growth defects and allow colonies to partially bypass the gfdA requirement in a high osmolarity glycerol pathway-dependent manner. Therefore, the findings of this study elucidate how saprophytic filamentous fungi have developed pathways distinct from those of budding yeasts to adapt to varied carbon sources and survive environmental stresses.
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Affiliation(s)
- Chi Zhang
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China
| | - Xiuhua Meng
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China
| | - Huiyu Gu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China
| | - Zhihua Ma
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China
| | - Ling Lu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China
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Kurucz V, Krüger T, Antal K, Dietl AM, Haas H, Pócsi I, Kniemeyer O, Emri T. Additional oxidative stress reroutes the global response of Aspergillus fumigatus to iron depletion. BMC Genomics 2018; 19:357. [PMID: 29747589 PMCID: PMC5946477 DOI: 10.1186/s12864-018-4730-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 04/26/2018] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Aspergillus fumigatus has to cope with a combination of several stress types while colonizing the human body. A functional interplay between these different stress responses can increase the chances of survival for this opportunistic human pathogen during the invasion of its host. In this study, we shed light on how the H2O2-induced oxidative stress response depends on the iron available to this filamentous fungus, using transcriptomic analysis, proteomic profiles, and growth assays. RESULTS The applied H2O2 treatment, which induced only a negligible stress response in iron-replete cultures, deleteriously affected the fungus under iron deprivation. The majority of stress-induced changes in gene and protein expression was not predictable from data coming from individual stress exposure and was only characteristic for the combination of oxidative stress plus iron deprivation. Our experimental data suggest that the physiological effects of combined stresses and the survival of the fungus highly depend on fragile balances between economization of iron and production of essential iron-containing proteins. One observed strategy was the overproduction of iron-independent antioxidant proteins to combat oxidative stress during iron deprivation, e.g. the upregulation of superoxide dismutase Sod1, the thioredoxin reductase Trr1, and the thioredoxin orthologue Afu5g11320. On the other hand, oxidative stress induction overruled iron deprivation-mediated repression of several genes. In agreement with the gene expression data, growth studies underlined that in A. fumigatus iron deprivation aggravates oxidative stress susceptibility. CONCLUSIONS Our data demonstrate that studying stress responses under separate single stress conditions is not sufficient to understand how A. fumigatus adapts in a complex and hostile habitat like the human body. The combinatorial stress of iron depletion and hydrogen peroxide caused clear non-additive effects upon the stress response of A. fumigatus. Our data further supported the view that the ability of A. fumigatus to cause diseases in humans strongly depends on its fitness attributes and less on specific virulence factors. In summary, A. fumigatus is able to mount and coordinate complex and efficient responses to combined stresses like iron deprivation plus H2O2-induced oxidative stress, which are exploited by immune cells to kill fungal pathogens.
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Affiliation(s)
- Vivien Kurucz
- Department of Biotechnology and Microbiology, Faculty of Sciences and Technology, University of Debrecen, Egyetem tér 1, Debrecen, H-4032 Hungary
| | - Thomas Krüger
- Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knöll Institute (HKI), 07745 Jena, Germany
| | - Károly Antal
- Department of Zoology, Faculty of Sciences, Eszterházy Károly University, Eszterházy tér 1, Eger, H-3300 Hungary
| | - Anna-Maria Dietl
- Division of Molecular Biology, Biocenter, Medical University of Innsbruck, A6020 Innsbruck, Austria
| | - Hubertus Haas
- Division of Molecular Biology, Biocenter, Medical University of Innsbruck, A6020 Innsbruck, Austria
| | - István Pócsi
- Department of Biotechnology and Microbiology, Faculty of Sciences and Technology, University of Debrecen, Egyetem tér 1, Debrecen, H-4032 Hungary
| | - Olaf Kniemeyer
- Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knöll Institute (HKI), 07745 Jena, Germany
| | - Tamás Emri
- Department of Biotechnology and Microbiology, Faculty of Sciences and Technology, University of Debrecen, Egyetem tér 1, Debrecen, H-4032 Hungary
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Bakti F, Sasse C, Heinekamp T, Pócsi I, Braus GH. Heavy Metal-Induced Expression of PcaA Provides Cadmium Tolerance to Aspergillus fumigatus and Supports Its Virulence in the Galleria mellonella Model. Front Microbiol 2018; 9:744. [PMID: 29706948 PMCID: PMC5909057 DOI: 10.3389/fmicb.2018.00744] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 03/29/2018] [Indexed: 11/23/2022] Open
Abstract
Most of the metal transporters in Aspergillus fumigatus are yet uncharacterized. Their role in fungal metabolism and virulence remains unclear. This paper describes the novel PIB-type cation ATPase PcaA, which links metal homeostasis and heavy metal tolerance in the opportunistic human pathogen A. fumigatus. The protein possesses conserved ATPase motif and shares 51% amino acid sequence identity with the Saccharomyces cerevisiae cadmium exporter Pca1p. A pcaA deletion, an overexpression and a gfp-pcaA complementation strain of A. fumigatus were constructed and their heavy metal susceptibilities were studied. The pcaA knock out strain showed drastically decreased cadmium tolerance, however, its growth was not affected by the exposure to high concentrations of copper, iron, zinc, or silver ions. Although the lack of PcaA had no effect on copper adaption, we demonstrated that not only cadmium but also copper ions are able to induce the transcription of pcaA in A. fumigatus wild type Af293. Similarly, cadmium and copper ions could induce the copper exporting ATPase crpA. These data imply a general response on the transcriptomic level to heavy metals in A. fumigatus through the induction of detoxification systems. Confocal microscopy of the gfp-pcaA complementation strain expressing functional GFP-PcaA supports the predicted membrane localization of PcaA. The GFP-PcaA fusion protein is located in the plasma membrane of A. fumigatus in the presence of cadmium ions. Virulence assays support a function of PcaA for virulence of A. fumigatus in the Galleria mellonella wax moth larvae model, which might be linked to the elimination of reactive oxygen species.
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Affiliation(s)
- Fruzsina Bakti
- Institute for Microbiology and Genetics, Department of Molecular Microbiology and Genetics, Goettingen Center for Molecular Biosciences, University of Göttingen, Göttingen, Germany.,Department of Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
| | - Christoph Sasse
- Institute for Microbiology and Genetics, Department of Molecular Microbiology and Genetics, Goettingen Center for Molecular Biosciences, University of Göttingen, Göttingen, Germany
| | - Thorsten Heinekamp
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute, Jena, Germany
| | - István Pócsi
- Department of Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
| | - Gerhard H Braus
- Institute for Microbiology and Genetics, Department of Molecular Microbiology and Genetics, Goettingen Center for Molecular Biosciences, University of Göttingen, Göttingen, Germany
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36
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Hopke A, Brown AJP, Hall RA, Wheeler RT. Dynamic Fungal Cell Wall Architecture in Stress Adaptation and Immune Evasion. Trends Microbiol 2018; 26:284-295. [PMID: 29452950 PMCID: PMC5869159 DOI: 10.1016/j.tim.2018.01.007] [Citation(s) in RCA: 123] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 01/23/2018] [Accepted: 01/25/2018] [Indexed: 12/28/2022]
Abstract
Deadly infections from opportunistic fungi have risen in frequency, largely because of the at-risk immunocompromised population created by advances in modern medicine and the HIV/AIDS pandemic. This review focuses on dynamics of the fungal polysaccharide cell wall, which plays an outsized role in fungal pathogenesis and therapy because it acts as both an environmental barrier and as the major interface with the host immune system. Human fungal pathogens use architectural strategies to mask epitopes from the host and prevent immune surveillance, and recent work elucidates how biotic and abiotic stresses present during infection can either block or enhance masking. The signaling components implicated in regulating fungal immune recognition can teach us how cell wall dynamics are controlled, and represent potential targets for interventions designed to boost or dampen immunity.
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Affiliation(s)
- Alex Hopke
- Molecular & Biomedical Sciences, University of Maine, Orono, ME, USA; Current address: BioMEMS Resource Center, Division of Surgery, Innovation and Bioengineering, Department of Surgery, Massachusetts General Hospital, Shriners Burns Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Alistair J P Brown
- MRC Centre for Medical Mycology, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, UK
| | - Rebecca A Hall
- Institute of Microbiology and Infection, and School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK
| | - Robert T Wheeler
- Molecular & Biomedical Sciences, University of Maine, Orono, ME, USA; Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, USA.
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37
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Fungal G-protein-coupled receptors: mediators of pathogenesis and targets for disease control. Nat Microbiol 2018; 3:402-414. [DOI: 10.1038/s41564-018-0127-5] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 02/09/2018] [Indexed: 12/31/2022]
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38
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Takahashi H, Kusuya Y, Hagiwara D, Takahashi-Nakaguchi A, Sakai K, Gonoi T. Global gene expression reveals stress-responsive genes in Aspergillus fumigatus mycelia. BMC Genomics 2017; 18:942. [PMID: 29202712 PMCID: PMC5715996 DOI: 10.1186/s12864-017-4316-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 11/17/2017] [Indexed: 11/10/2022] Open
Abstract
Background Aspergillus fumigatus is a human fungal pathogen that causes aspergillosis in immunocompromised hosts. A. fumigatus is believed to be exposed to diverse environmental stresses in the host cells. The adaptation mechanisms are critical for infections in human bodies. Transcriptional networks in response to diverse environmental challenges remain to be elucidated. To gain insights into the adaptation to environmental stresses in A. fumigatus mycelia, we conducted time series transcriptome analyses. Results With the aid of RNA-seq, we explored the global gene expression profiles of mycelia in A. fumigatus upon exposure to diverse environmental changes, including heat, superoxide, and osmotic stresses. From the perspective of global transcriptomes, transient responses to superoxide and osmotic stresses were observed while responses to heat stresses were gradual. We identified the stress-responsive genes for particular stresses, and the 266 genes whose expression levels drastically fluctuated upon exposure to all tested stresses. Among these, the 77 environmental stress response genes are conserved in S. cerevisiae, suggesting that these genes might be more general prerequisites for adaptation to environmental stresses. Finally, we revealed the strong correlations among expression profiles of genes related to ‘rRNA processing’. Conclusions The time series transcriptome analysis revealed the stress-responsive genes underlying the adaptation mechanisms in A. fumigatus mycelia. These results will shed light on the regulatory networks underpinning the adaptation of the filamentous fungi. Electronic supplementary material The online version of this article (10.1186/s12864-017-4316-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hiroki Takahashi
- Medical Mycology Research Center, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8673, Japan. .,Molecular Chirality Research Center, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan.
| | - Yoko Kusuya
- Medical Mycology Research Center, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8673, Japan
| | - Daisuke Hagiwara
- Medical Mycology Research Center, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8673, Japan
| | | | - Kanae Sakai
- Medical Mycology Research Center, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8673, Japan
| | - Tohru Gonoi
- Medical Mycology Research Center, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8673, Japan
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Boral H, Metin B, Döğen A, Seyedmousavi S, Ilkit M. Overview of selected virulence attributes in Aspergillus fumigatus, Candida albicans, Cryptococcus neoformans, Trichophyton rubrum, and Exophiala dermatitidis. Fungal Genet Biol 2017; 111:92-107. [PMID: 29102684 DOI: 10.1016/j.fgb.2017.10.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 10/24/2017] [Accepted: 10/27/2017] [Indexed: 12/13/2022]
Abstract
The incidence of fungal diseases has been increasing since 1980, and is associated with excessive morbidity and mortality, particularly among immunosuppressed patients. Of the known 625 pathogenic fungal species, infections caused by the genera Aspergillus, Candida, Cryptococcus, and Trichophyton are responsible for more than 300 million estimated episodes of acute or chronic infections worldwide. In addition, a rather neglected group of opportunistic fungi known as black yeasts and their filamentous relatives cause a wide variety of recalcitrant infections in both immunocompetent and immunosuppressed hosts. This article provides an overview of selected virulence factors that are known to suppress host immunity and enhance the infectivity of these fungi.
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Affiliation(s)
- Hazal Boral
- Division of Mycology, Department of Microbiology, Faculty of Medicine, University of Çukurova, Adana, Turkey
| | - Banu Metin
- Department of Food Engineering, Faculty of Engineering and Natural Sciences, Istanbul Sabahattin Zaim University, Istanbul, Turkey
| | - Aylin Döğen
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy, University of Mersin, Mersin, Turkey
| | - Seyedmojtaba Seyedmousavi
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands; Invasive Fungi Research Center, Mazandaran University of Medical Sciences, Sari, Iran; Center of Excellence for Infection Biology and Antimicrobial Pharmacology, Tehran, Iran
| | - Macit Ilkit
- Division of Mycology, Department of Microbiology, Faculty of Medicine, University of Çukurova, Adana, Turkey.
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Abstract
Aspergillus fumigatus is an environmental filamentous fungus that can cause life-threatening disease in immunocompromised individuals. The interactions between A. fumigatus and the host environment are dynamic and complex. The host immune system needs to recognize the distinct morphological forms of A. fumigatus to control fungal growth and prevent tissue invasion, whereas the fungus requires nutrients and needs to adapt to the hostile environment by escaping immune recognition and counteracting host responses. Understanding these highly dynamic interactions is necessary to fully understand the pathogenesis of aspergillosis and to facilitate the design of new therapeutics to overcome the morbidity and mortality caused by A. fumigatus. In this Review, we describe how A. fumigatus adapts to environmental change, the mechanisms of host defence, and our current knowledge of the interplay between the host immune response and the fungus.
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Transcriptome-Based Modeling Reveals that Oxidative Stress Induces Modulation of the AtfA-Dependent Signaling Networks in Aspergillus nidulans. Int J Genomics 2017; 2017:6923849. [PMID: 28770220 PMCID: PMC5523550 DOI: 10.1155/2017/6923849] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 05/17/2017] [Accepted: 06/13/2017] [Indexed: 01/01/2023] Open
Abstract
To better understand the molecular functions of the master stress-response regulator AtfA in Aspergillus nidulans, transcriptomic analyses of the atfA null mutant and the appropriate control strains exposed to menadione sodium bisulfite- (MSB-), t-butylhydroperoxide- and diamide-induced oxidative stresses were performed. Several elements of oxidative stress response were differentially expressed. Many of them, including the downregulation of the mitotic cell cycle, as the MSB stress-specific upregulation of FeS cluster assembly and the MSB stress-specific downregulation of nitrate reduction, tricarboxylic acid cycle, and ER to Golgi vesicle-mediated transport, showed AtfA dependence. To elucidate the potential global regulatory role of AtfA governing expression of a high number of genes with very versatile biological functions, we devised a model based on the comprehensive transcriptomic data. Our model suggests that an important function of AtfA is to modulate the transduction of stress signals. Although it may regulate directly only a limited number of genes, these include elements of the signaling network, for example, members of the two-component signal transduction systems. AtfA acts in a stress-specific manner, which may increase further the number and diversity of AtfA-dependent genes. Our model sheds light on the versatility of the physiological functions of AtfA and its orthologs in fungi.
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Zhi QQ, Li JY, Liu QY, He ZM. A cytosine methyltransferase ortholog dmtA is involved in the sensitivity of Aspergillus flavus to environmental stresses. Fungal Biol 2017; 121:501-514. [DOI: 10.1016/j.funbio.2017.02.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 01/21/2017] [Accepted: 02/01/2017] [Indexed: 01/05/2023]
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Krappmann S. How to invade a susceptible host: cellular aspects of aspergillosis. Curr Opin Microbiol 2016; 34:136-146. [PMID: 27816786 DOI: 10.1016/j.mib.2016.10.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 10/12/2016] [Accepted: 10/17/2016] [Indexed: 02/07/2023]
Abstract
Diseases caused by Aspergillus spp. and in particular A. fumigatus are manifold and affect individuals suffering from immune dysfunctions, among them immunocompromised ones. The determinants of whether the encounter of a susceptible host with infectious propagules of this filamentous saprobe results in infection have been characterized to a limited extent. Several cellular characteristics of A. fumigatus that have evolved in its natural environment contribute to its virulence, among them general traits as well as particular ones that affect interaction with the mammalian host. Among the latter, conidial constituents, cell wall components, secreted proteins as well as extrolites shape the tight interaction of A. fumigatus with the host milieu and also contribute to evasion from immune surveillance.
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Affiliation(s)
- Sven Krappmann
- Institute of Microbiology - Clinical Microbiology, Immunology and Hygiene, University Hospital Erlangen and Friedrich-Alexander University Erlangen-Nürnberg, Wasserturmstr. 3/5, D-91054 Erlangen, Germany.
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Pereira Silva L, Alves de Castro P, Dos Reis TF, Paziani MH, Von Zeska Kress MR, Riaño-Pachón DM, Hagiwara D, Ries LNA, Brown NA, Goldman GH. Genome-wide transcriptome analysis of Aspergillus fumigatus exposed to osmotic stress reveals regulators of osmotic and cell wall stresses that are SakA HOG1 and MpkC dependent. Cell Microbiol 2016; 19. [PMID: 27706915 DOI: 10.1111/cmi.12681] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 09/19/2016] [Accepted: 10/04/2016] [Indexed: 12/24/2022]
Abstract
Invasive aspergillosis is predominantly caused by Aspergillus fumigatus, and adaptations to stresses experienced within the human host are a prerequisite for the survival and virulence strategies of the pathogen. The central signal transduction pathway operating during hyperosmotic stress is the high osmolarity glycerol mitogen-activated protein kinase cascade. A. fumigatus MpkC and SakA, orthologues of the Saccharomyces cerevisiae Hog1p, constitute the primary regulator of the hyperosmotic stress response. We compared A. fumigatus wild-type transcriptional response to osmotic stress with the ΔmpkC, ΔsakA, and ΔmpkC ΔsakA strains. Our results strongly indicate that MpkC and SakA have independent and collaborative functions during the transcriptional response to transient osmotic stress. We have identified and characterized null mutants for four A. fumigatus basic leucine zipper proteins transcription factors. The atfA and atfB have comparable expression levels with the wild-type in ΔmpkC but are repressed in ΔsakA and ΔmpkC ΔsakA post-osmotic stress. The atfC and atfD have reduced expression levels in all mutants post-osmotic stress. The atfA-D null mutants displayed several phenotypes related to osmotic, oxidative, and cell wall stresses. The ΔatfA and ΔatfB were shown to be avirulent and to have attenuated virulence, respectively, in both Galleria mellonella and a neutropenic murine model of invasive pulmonary aspergillosis.
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Affiliation(s)
- Lilian Pereira Silva
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Patrícia Alves de Castro
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Thaila Fernanda Dos Reis
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Mario Henrique Paziani
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | | | - Diego M Riaño-Pachón
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), São Paulo, Brazil
| | - Daisuke Hagiwara
- Medical Mycology Research Center, Chiba University, Chiba, Japan
| | - Laure N A Ries
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Neil Andrew Brown
- Plant Biology and Crop Science, Rothamsted Research, Harpenden, Hertfordshire, UK
| | - Gustavo H Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
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Pais P, Costa C, Cavalheiro M, Romão D, Teixeira MC. Transcriptional Control of Drug Resistance, Virulence and Immune System Evasion in Pathogenic Fungi: A Cross-Species Comparison. Front Cell Infect Microbiol 2016; 6:131. [PMID: 27812511 PMCID: PMC5072224 DOI: 10.3389/fcimb.2016.00131] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 09/29/2016] [Indexed: 12/26/2022] Open
Abstract
Transcription factors are key players in the control of the activation or repression of gene expression programs in response to environmental stimuli. The study of regulatory networks taking place in fungal pathogens is a promising research topic that can help in the fight against these pathogens by targeting specific fungal pathways as a whole, instead of targeting more specific effectors of virulence or drug resistance. This review is focused on the analysis of regulatory networks playing a central role in the referred mechanisms in the human fungal pathogens Aspergillus fumigatus, Cryptococcus neoformans, Candida albicans, Candida glabrata, Candida parapsilosis, and Candida tropicalis. Current knowledge on the activity of the transcription factors characterized in each of these pathogenic fungal species will be addressed. Particular focus is given to their mechanisms of activation, regulatory targets and phenotypic outcome. The review further provides an evaluation on the conservation of transcriptional circuits among different fungal pathogens, highlighting the pathways that translate common or divergent traits among these species in what concerns their drug resistance, virulence and host immune evasion features. It becomes evident that the regulation of transcriptional networks is complex and presents significant variations among different fungal pathogens. Only the oxidative stress regulators Yap1 and Skn7 are conserved among all studied species; while some transcription factors, involved in nutrient homeostasis, pH adaptation, drug resistance and morphological switching are present in several, though not all species. Interestingly, in some cases not very homologous transcription factors display orthologous functions, whereas some homologous proteins have diverged in terms of their function in different species. A few cases of species specific transcription factors are also observed.
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Affiliation(s)
- Pedro Pais
- Biological Sciences Research Group, Department of Bioengineering, Instituto Superior Técnico, Universidade de LisboaLisbon, Portugal; Biological Sciences Research Group, Institute for Bioengineering and Biosciences, Instituto Superior TécnicoLisboa, Portugal
| | - Catarina Costa
- Biological Sciences Research Group, Department of Bioengineering, Instituto Superior Técnico, Universidade de LisboaLisbon, Portugal; Biological Sciences Research Group, Institute for Bioengineering and Biosciences, Instituto Superior TécnicoLisboa, Portugal
| | - Mafalda Cavalheiro
- Biological Sciences Research Group, Department of Bioengineering, Instituto Superior Técnico, Universidade de LisboaLisbon, Portugal; Biological Sciences Research Group, Institute for Bioengineering and Biosciences, Instituto Superior TécnicoLisboa, Portugal
| | - Daniela Romão
- Biological Sciences Research Group, Department of Bioengineering, Instituto Superior Técnico, Universidade de LisboaLisbon, Portugal; Biological Sciences Research Group, Institute for Bioengineering and Biosciences, Instituto Superior TécnicoLisboa, Portugal
| | - Miguel C Teixeira
- Biological Sciences Research Group, Department of Bioengineering, Instituto Superior Técnico, Universidade de LisboaLisbon, Portugal; Biological Sciences Research Group, Institute for Bioengineering and Biosciences, Instituto Superior TécnicoLisboa, Portugal
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Al-Bader N, Sheppard DC. Aspergillosis and stem cell transplantation: An overview of experimental pathogenesis studies. Virulence 2016; 7:950-966. [PMID: 27687755 DOI: 10.1080/21505594.2016.1231278] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Invasive aspergillosis is a life-threatening infection caused by the opportunistic filamentous fungus Aspergillus fumigatus. Patients undergoing haematopoietic stem cell transplant (HSCT) for the treatment of hematological malignancy are at particularly high risk of developing this fatal infection. The susceptibility of HSCT patients to infection with A. fumigatus is a consequence of a complex interplay of both fungal and host factors. Here we review our understanding of the host-pathogen interactions underlying the susceptibility of the immunocompromised host to infection with A. fumigatus with a focus on the experimental validation of fungal and host factors relevant to HSCT patients. These include fungal factors such as secondary metabolites, cell wall constituents, and metabolic adaptations that facilitate immune evasion and survival within the host microenvironment, as well as the innate and adaptive immune responses involved in host defense against A. fumigatus.
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Affiliation(s)
- Nadia Al-Bader
- a Departments of Medicine, Microbiology and Immunology , McGill University , Montréal , Québec , Canada
| | - Donald C Sheppard
- a Departments of Medicine, Microbiology and Immunology , McGill University , Montréal , Québec , Canada.,b Infectious Diseases in Global Health Program, Research Institute of the McGill University Health Center, McGill University , Montréal , Québec , Canada
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Hagiwara D, Watanabe A, Kamei K, Goldman GH. Epidemiological and Genomic Landscape of Azole Resistance Mechanisms in Aspergillus Fungi. Front Microbiol 2016; 7:1382. [PMID: 27708619 PMCID: PMC5030247 DOI: 10.3389/fmicb.2016.01382] [Citation(s) in RCA: 110] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 08/22/2016] [Indexed: 11/13/2022] Open
Abstract
Invasive aspergillosis is a life-threatening mycosis caused by the pathogenic fungus Aspergillus. The predominant causal species is Aspergillus fumigatus, and azole drugs are the treatment of choice. Azole drugs approved for clinical use include itraconazole, voriconazole, posaconazole, and the recently added isavuconazole. However, epidemiological research has indicated that the prevalence of azole-resistant A. fumigatus isolates has increased significantly over the last decade. What is worse is that azole-resistant strains are likely to have emerged not only in response to long-term drug treatment but also because of exposure to azole fungicides in the environment. Resistance mechanisms include amino acid substitutions in the target Cyp51A protein, tandem repeat sequence insertions at the cyp51A promoter, and overexpression of the ABC transporter Cdr1B. Environmental azole-resistant strains harboring the association of a tandem repeat sequence and punctual mutation of the Cyp51A gene (TR34/L98H and TR46/Y121F/T289A) have become widely disseminated across the world within a short time period. The epidemiological data also suggests that the number of Aspergillus spp. other than A. fumigatus isolated has risen. Some non-fumigatus species intrinsically show low susceptibility to azole drugs, imposing the need for accurate identification, and drug susceptibility testing in most clinical cases. Currently, our knowledge of azole resistance mechanisms in non-fumigatus Aspergillus species such as A. flavus, A. niger, A. tubingensis, A. terreus, A. fischeri, A. lentulus, A. udagawae, and A. calidoustus is limited. In this review, we present recent advances in our understanding of azole resistance mechanisms particularly in A. fumigatus. We then provide an overview of the genome sequences of non-fumigatus species, focusing on the proteins related to azole resistance mechanisms.
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Affiliation(s)
| | - Akira Watanabe
- Medical Mycology Research Center, Chiba University Chiba, Japan
| | - Katsuhiko Kamei
- Medical Mycology Research Center, Chiba University Chiba, Japan
| | - Gustavo H Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo Ribeirão Preto, Brazil
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de Castro PA, Chiaratto J, Morais ER, Dos Reis TF, Mitchell TK, Brown NA, Goldman GH. The putative flavin carrier family FlcA-C is important for Aspergillus fumigatus virulence. Virulence 2016; 8:797-809. [PMID: 27652896 DOI: 10.1080/21505594.2016.1239010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Aspergillus fumigatus is an opportunistic fungal pathogen and the most important species causing pulmonary fungal infections. The signaling by calcium is very important for A. fumigatus pathogenicity and it is regulated by the transcription factor CrzA. We have previously used used ChIP-seq (Chromatin Immunoprecipitation DNA sequencing) aiming to identify gene targets regulated by CrzA. We have identified among several genes regulated by calcium stress, the putative flavin transporter, flcA. This transporter belongs to a small protein family composed of FlcA, B, and C. The ΔflcA null mutant showed several phenotypes, such as morphological defects, increased sensitivity to calcium chelating-agent ethylene glycol tetraacetic acid (EGTA), cell wall or oxidative damaging agents and metals, repre-sentative of deficiencies in calcium signaling and iron homeostasis. Increasing calcium concentrations improved significantly the ΔflcA growth and conidiation, indicating that ΔflcA mutant has calcium insufficiency. Finally, ΔflcA-C mutants showed reduced flavin adenine dinucleotide (FAD) and were avirulent in a low dose murine infection model.
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Affiliation(s)
- Patrícia A de Castro
- a Faculdade de Ciências Farmacêuticas de Ribeirão Preto and Faculdade de Medicina de Ribeirão Preto , Universidade de São Paulo , Ribeirão Preto , Brazil
| | - Jéssica Chiaratto
- a Faculdade de Ciências Farmacêuticas de Ribeirão Preto and Faculdade de Medicina de Ribeirão Preto , Universidade de São Paulo , Ribeirão Preto , Brazil
| | - Enyara Rezende Morais
- a Faculdade de Ciências Farmacêuticas de Ribeirão Preto and Faculdade de Medicina de Ribeirão Preto , Universidade de São Paulo , Ribeirão Preto , Brazil
| | - Thaila Fernanda Dos Reis
- a Faculdade de Ciências Farmacêuticas de Ribeirão Preto and Faculdade de Medicina de Ribeirão Preto , Universidade de São Paulo , Ribeirão Preto , Brazil
| | - Thomas K Mitchell
- b Department of Plant Pathology , The Ohio State University , Columbus , OH , USA
| | - Neil A Brown
- c Plant Biology and Crop Science, Rothamsted Research , Harpenden, Herts , UK
| | - Gustavo H Goldman
- a Faculdade de Ciências Farmacêuticas de Ribeirão Preto and Faculdade de Medicina de Ribeirão Preto , Universidade de São Paulo , Ribeirão Preto , Brazil
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Aspergillus fumigatus MADS-Box Transcription Factor rlmA Is Required for Regulation of the Cell Wall Integrity and Virulence. G3-GENES GENOMES GENETICS 2016; 6:2983-3002. [PMID: 27473315 PMCID: PMC5015955 DOI: 10.1534/g3.116.031112] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The Cell Wall Integrity (CWI) pathway is the primary signaling cascade that controls the de novo synthesis of the fungal cell wall, and in Saccharomyces cerevisiae this event is highly dependent on the RLM1 transcription factor. Here, we investigated the function of RlmA in the fungal pathogen Aspergillus fumigatus. We show that the ΔrlmA strain exhibits an altered cell wall organization in addition to defects related to vegetative growth and tolerance to cell wall-perturbing agents. A genetic analysis indicated that rlmA is positioned downstream of the pkcA and mpkA genes in the CWI pathway. As a consequence, rlmA loss-of-function leads to the altered expression of genes encoding cell wall-related proteins. RlmA positively regulates the phosphorylation of MpkA and is induced at both protein and transcriptional levels during cell wall stress. The rlmA was also involved in tolerance to oxidative damage and transcriptional regulation of genes related to oxidative stress adaptation. Moreover, the ΔrlmA strain had attenuated virulence in a neutropenic murine model of invasive pulmonary aspergillosis. Our results suggest that RlmA functions as a transcription factor in the A. fumigatus CWI pathway, acting downstream of PkcA-MpkA signaling and contributing to the virulence of this fungus.
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Moloney NM, Owens RA, Doyle S. Proteomic analysis of Aspergillus fumigatus – clinical implications. Expert Rev Proteomics 2016; 13:635-49. [DOI: 10.1080/14789450.2016.1203783] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
| | | | - Sean Doyle
- Department of Biology, Maynooth University, Maynooth, Ireland
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