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Liu F, Zeng M, Zhou X, Huang F, Song Z. Aspergillus fumigatus escape mechanisms from its harsh survival environments. Appl Microbiol Biotechnol 2024; 108:53. [PMID: 38175242 DOI: 10.1007/s00253-023-12952-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 10/09/2023] [Accepted: 10/19/2023] [Indexed: 01/05/2024]
Abstract
Aspergillus fumigatus is a ubiquitous pathogenic mold and causes several diseases, including mycotoxicosis, allergic reactions, and systemic diseases (invasive aspergillosis), with high mortality rates. In its ecological niche, the fungus has evolved and mastered many reply strategies to resist and survive against negative threats, including harsh environmental stress and deficiency of essential nutrients from natural environments, immunity responses and drug treatments in host, and competition from symbiotic microorganisms. Hence, treating A. fumigatus infection is a growing challenge. In this review, we summarized A. fumigatus reply strategies and escape mechanisms and clarified the main competitive or symbiotic relationships between A. fumigatus, viruses, bacteria, or fungi in host microecology. Additionally, we discussed the contemporary drug repertoire used to treat A. fumigatus and the latest evidence of potential resistance mechanisms. This review provides valuable knowledge which will stimulate further investigations and clinical applications for treating and preventing A. fumigatus infections. KEY POINTS: • Harsh living environment was a great challenge for A. fumigatus survival. • A. fumigatus has evolved multiple strategies to escape host immune responses. • A. fumigatus withstands antifungal drugs via intrinsic escape mechanisms.
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Affiliation(s)
- Fangyan Liu
- School of Basic Medical Sciences, Southwest Medical University, Luzhou, 646000, People's Republic of China
| | - Meng Zeng
- School of Basic Medical Sciences, Southwest Medical University, Luzhou, 646000, People's Republic of China
- Department of Clinical Laboratory, Yongchuan Hospital of Chongqing Medical University, Chongqing, 402160, People's Republic of China
| | - Xue Zhou
- School of Basic Medical Sciences, Southwest Medical University, Luzhou, 646000, People's Republic of China
| | - Fujiao Huang
- School of Basic Medical Sciences, Southwest Medical University, Luzhou, 646000, People's Republic of China
| | - Zhangyong Song
- School of Basic Medical Sciences, Southwest Medical University, Luzhou, 646000, People's Republic of China.
- Molecular Biotechnology Platform, Public Center of Experimental Technology, Southwest Medical University, Luzhou, 646000, People's Republic of China.
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2
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van Rhijn N, Zhao C, Al-Furaiji N, Storer ISR, Valero C, Gago S, Chown H, Baldin C, Grant RF, Bin Shuraym H, Ivanova L, Kniemeyer O, Krüger T, Bignell E, Goldman GH, Amich J, Delneri D, Bowyer P, Brakhage AA, Haas H, Bromley MJ. Functional analysis of the Aspergillus fumigatus kinome identifies a druggable DYRK kinase that regulates septal plugging. Nat Commun 2024; 15:4984. [PMID: 38862481 PMCID: PMC11166925 DOI: 10.1038/s41467-024-48592-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 05/03/2024] [Indexed: 06/13/2024] Open
Abstract
More than 10 million people suffer from lung diseases caused by the pathogenic fungus Aspergillus fumigatus. Azole antifungals represent first-line therapeutics for most of these infections but resistance is rising, therefore the identification of antifungal targets whose inhibition synergises with the azoles could improve therapeutic outcomes. Here, we generate a library of 111 genetically barcoded null mutants of Aspergillus fumigatus in genes encoding protein kinases, and show that loss of function of kinase YakA results in hypersensitivity to the azoles and reduced pathogenicity. YakA is an orthologue of Candida albicans Yak1, a TOR signalling pathway kinase involved in modulation of stress responsive transcriptional regulators. We show that YakA has been repurposed in A. fumigatus to regulate blocking of the septal pore upon exposure to stress. Loss of YakA function reduces the ability of A. fumigatus to penetrate solid media and to grow in mouse lung tissue. We also show that 1-ethoxycarbonyl-beta-carboline (1-ECBC), a compound previously shown to inhibit C. albicans Yak1, prevents stress-mediated septal spore blocking and synergises with the azoles to inhibit A. fumigatus growth.
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Affiliation(s)
- Norman van Rhijn
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Can Zhao
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Narjes Al-Furaiji
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
- Department of Pharmacology, College of Medicine, University of Kerbala, Kerbala, Iraq
| | - Isabelle S R Storer
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Clara Valero
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Sara Gago
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Harry Chown
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Clara Baldin
- Division of Molecular Biology, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | - Rachael-Fortune Grant
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Hajer Bin Shuraym
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Saud Bin Abdulaziz University for Health Sciences, 11481, Riyadh, Saudi Arabia
| | - Lia Ivanova
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology (Leibniz-HKI), Jena, Germany
| | - Olaf Kniemeyer
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology (Leibniz-HKI), Jena, Germany
| | - Thomas Krüger
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology (Leibniz-HKI), Jena, Germany
| | - Elaine Bignell
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
- MRC Centre for Medical Mycology, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
| | - Gustavo H Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Jorge Amich
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
- Mycology Reference Laboratory (Laboratorio de Referencia e Investigación en Micología [LRIM]), National Centre for Microbiology, Instituto de Salud Carlos III (ISCIII), Majadahonda, Madrid, Spain
| | - Daniela Delneri
- Division of Evolution, Infection and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Paul Bowyer
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Axel A Brakhage
- Department of Microbiology and Molecular Biology, Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Hubertus Haas
- Division of Molecular Biology, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | - Michael J Bromley
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK.
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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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van Rhijn N, Zhao C, Al-Furaji N, Storer I, Valero C, Gago S, Chown H, Baldin C, Fortune-Grant R, Shuraym HB, Ivanova L, Kniemeyer O, Krüger T, Bignell E, Goldman G, Amich J, Delneri D, Bowyer P, Brakhage A, Haas H, Bromley M. Functional analysis of the Aspergillus fumigatus kinome reveals a DYRK kinase involved in septal plugging is a novel antifungal drug target. RESEARCH SQUARE 2023:rs.3.rs-2960526. [PMID: 37398159 PMCID: PMC10312919 DOI: 10.21203/rs.3.rs-2960526/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
More than 10 million people suffer from lung diseases caused by the pathogenic fungus Aspergillus fumigatus. The azole class of antifungals represent first line therapeutics for most of these infections however resistance is rising. Identification of novel antifungal targets that, when inhibited, synergise with the azoles will aid the development of agents that can improve therapeutic outcomes and supress the emergence of resistance. As part of the A. fumigatus genome-wide knockout program (COFUN), we have completed the generation of a library that consists of 120 genetically barcoded null mutants in genes that encode the protein kinase cohort of A. fumigatus. We have employed a competitive fitness profiling approach (Bar-Seq), to identify targets which when deleted result in hypersensitivity to the azoles and fitness defects in a murine host. The most promising candidate from our screen is a previously uncharacterised DYRK kinase orthologous to Yak1 of Candida albicans, a TOR signalling pathway kinase involved in modulation of stress responsive transcriptional regulators. Here we show that the orthologue YakA has been repurposed in A. fumigatus to regulate blocking of the septal pore upon exposure to stress via phosphorylation of the Woronin body tethering protein Lah. Loss of YakA function reduces the ability of A. fumigatus to penetrate solid media and impacts growth in murine lung tissue. We also show that 1-ethoxycarbonyl-beta-carboline (1-ECBC), a compound previously shown to inhibit Yak1 in C. albicans prevents stress mediated septal spore blocking and synergises with the azoles to inhibit A. fumigatus growth.
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Affiliation(s)
| | - Can Zhao
- Manchester Fungal Infection Group
| | | | | | | | | | | | | | | | | | - Lia Ivanova
- Leibniz Institute for Natural Product Research and Infection Biology
| | - Olaf Kniemeyer
- Leibniz Institute for Natural Product Research and Infection Biology
| | - Thomas Krüger
- Leibniz Institute for Natural Product Research and Infection Biology
| | | | - Gustavo Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Bloco Q, Universidade de São Paulo
| | | | | | | | - Axel Brakhage
- Leibniz Institute for Natural Product Research and Infection Biology - University of Jena
| | - Hubertus Haas
- Institute of Molecular Biology/Biocenter, Innsbruck Medical University
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Shankar J. Insight into the metabolic changes during germination of Aspergillus niger conidia using nLC-qTOF. Biologia (Bratisl) 2022. [DOI: 10.1007/s11756-022-01115-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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6
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Liu H, Xu W, Bruno VM, Phan QT, Solis NV, Woolford CA, Ehrlich RL, Shetty AC, McCraken C, Lin J, Bromley MJ, Mitchell AP, Filler SG. Determining Aspergillus fumigatus transcription factor expression and function during invasion of the mammalian lung. PLoS Pathog 2021; 17:e1009235. [PMID: 33780518 PMCID: PMC8031882 DOI: 10.1371/journal.ppat.1009235] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 04/08/2021] [Accepted: 03/20/2021] [Indexed: 12/14/2022] Open
Abstract
To gain a better understanding of the transcriptional response of Aspergillus fumigatus during invasive pulmonary infection, we used a NanoString nCounter to assess the transcript levels of 467 A. fumigatus genes during growth in the lungs of immunosuppressed mice. These genes included ones known to respond to diverse environmental conditions and those encoding most transcription factors in the A. fumigatus genome. We found that invasive growth in vivo induces a unique transcriptional profile as the organism responds to nutrient limitation and attack by host phagocytes. This in vivo transcriptional response is largely mimicked by in vitro growth in Aspergillus minimal medium that is deficient in nitrogen, iron, and/or zinc. From the transcriptional profiling data, we selected 9 transcription factor genes that were either highly expressed or strongly up-regulated during in vivo growth. Deletion mutants were constructed for each of these genes and assessed for virulence in mice. Two transcription factor genes were found to be required for maximal virulence. One was rlmA, which is required for the organism to achieve maximal fungal burden in the lung. The other was sltA, which regulates of the expression of multiple secondary metabolite gene clusters and mycotoxin genes independently of laeA. Using deletion and overexpression mutants, we determined that the attenuated virulence of the ΔsltA mutant is due in part to decreased expression aspf1, which specifies a ribotoxin, but is not mediated by reduced expression of the fumigaclavine gene cluster or the fumagillin-pseruotin supercluster. Thus, in vivo transcriptional profiling focused on transcription factors genes provides a facile approach to identifying novel virulence regulators. Although A. fumigatus causes the majority of cases of invasive aspergillosis, the function of most genes in its genome remains unknown. To identify genes encoding transcription factors that may be important for virulence, we used a NanoString nCounter to measure the mRNA levels of A. fumigatus transcription factor genes in the lungs of mice with invasive aspergillosis. The transcriptional profiling data indicate that the organism is exposed to nutrient limitation and stress during growth in the lungs, and that it responds by up-regulating genes that encode mycotoxins and secondary metabolites. In vitro, this response was most closely mimicked by growth in medium that was deficient in nitrogen, iron and/or zinc. Using the transcriptional profiling data, we identified two transcription factors that govern A. fumigatus virulence. These were RlmA, which is governs factors that enables the organism to proliferate maximally in the lung and SltA, which controls the production of mycotoxins and secondary metabolites.
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Affiliation(s)
- Hong Liu
- Division of Infectious Diseases, Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA, United States of America
| | - Wenjie Xu
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, United States of America
| | - Vincent M. Bruno
- Department of Microbiology and Immunology, University of Maryland, Baltimore, MD, United States of America
| | - Quynh T. Phan
- Division of Infectious Diseases, Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA, United States of America
| | - Norma V. Solis
- Division of Infectious Diseases, Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA, United States of America
| | - Carol A. Woolford
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, United States of America
| | - Rachel L. Ehrlich
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, United States of America
| | - Amol C. Shetty
- Institute for Genome Sciences, University of Maryland, Baltimore, MD, United States of America
| | - Carrie McCraken
- Institute for Genome Sciences, University of Maryland, Baltimore, MD, United States of America
| | - Jianfeng Lin
- Division of Infectious Diseases, Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA, United States of America
| | - Michael J. Bromley
- Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Core Technology Facility, and Lydia Becker Institute of Immunology and Inflammation, Biology, Medicine and Health. The University of Manchester, Manchester Academic Health Science Centre, MA, United Kingdom
| | - Aaron P. Mitchell
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, United States of America
- Department of Microbiology, University of Georgia, Athens, GA, United States of America
- * E-mail: (APM); (SGF)
| | - Scott G. Filler
- Division of Infectious Diseases, Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA, United States of America
- David Geffen School of Medicine at UCLA, Los Angeles, CA, United States of America
- * E-mail: (APM); (SGF)
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Zhang T, Cao Q, Li N, Liu D, Yuan Y. Transcriptome analysis of fungicide-responsive gene expression profiles in two Penicillium italicum strains with different response to the sterol demethylation inhibitor (DMI) fungicide prochloraz. BMC Genomics 2020; 21:156. [PMID: 32050894 PMCID: PMC7017498 DOI: 10.1186/s12864-020-6564-6] [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] [Received: 11/25/2018] [Accepted: 02/07/2020] [Indexed: 12/19/2022] Open
Abstract
Background Penicillium italicum (blue mold) is one of citrus pathogens causing undesirable citrus fruit decay even at strictly-controlled low temperatures (< 10 °C) during shipping and storage. P. italicum isolates with considerably high resistance to sterol demethylation inhibitor (DMI) fungicides have emerged; however, mechanism(s) underlying such DMI-resistance remains unclear. In contrast to available elucidation on anti-DMI mechanism for P. digitatum (green mold), how P. italicum DMI-resistance develops has not yet been clarified. Results The present study prepared RNA-sequencing (RNA-seq) libraries for two P. italicum strains (highly resistant (Pi-R) versus highly sensitive (Pi-S) to DMI fungicides), with and without prochloraz treatment, to identify prochloraz-responsive genes facilitating DMI-resistance. After 6 h prochloraz-treatment, comparative transcriptome profiling showed more differentially expressed genes (DEGs) in Pi-R than Pi-S. Functional enrichments identified 15 DEGs in the prochloraz-induced Pi-R transcriptome, simultaneously up-regulated in P. italicum resistance. These included ATP-binding cassette (ABC) transporter-encoding genes, major facilitator superfamily (MFS) transporter-encoding genes, ergosterol (ERG) anabolism component genes ERG2, ERG6 and EGR11 (CYP51A), mitogen-activated protein kinase (MAPK) signaling-inducer genes Mkk1 and Hog1, and Ca2+/calmodulin-dependent kinase (CaMK) signaling-inducer genes CaMK1 and CaMK2. Fragments Per Kilobase per Million mapped reads (FPKM) analysis of Pi-R transcrtiptome showed that prochloraz induced mRNA increase of additional 4 unigenes, including the other two ERG11 isoforms CYP51B and CYP51C and the remaining kinase-encoding genes (i.e., Bck1 and Slt2) required for Slt2-MAPK signaling. The expression patterns of all the 19 prochloraz-responsive genes, obtained in our RNA-seq data sets, have been validated by quantitative real-time PCR (qRT-PCR). These lines of evidence in together draw a general portrait of anti-DMI mechanisms for P. italicum species. Intriguingly, some strategies adopted by the present Pi-R were not observed in the previously documented prochloraz-resistant P. digitatum transcrtiptomes. These included simultaneous induction of all major EGR11 isoforms (CYP51A/B/C), over-expression of ERG2 and ERG6 to modulate ergosterol anabolism, and concurrent mobilization of Slt2-MAPK and CaMK signaling processes to overcome fungicide-induced stresses. Conclusions The present findings provided transcriptomic evidence on P. italicum DMI-resistance mechanisms and revealed some diversity in anti-DMI strategies between P. italicum and P. digitatum species, contributing to our knowledge on P. italicum DMI-resistance mechanisms.
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Affiliation(s)
- Tingfu Zhang
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China
| | - Qianwen Cao
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China
| | - Na Li
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China.,Yunnan Higher Education Institutions, College of Life Science and Technology, Honghe University, Mengzi, 661199, China
| | - Deli Liu
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China.
| | - Yongze Yuan
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China.
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The Aspergillus fumigatus Phosphoproteome Reveals Roles of High-Osmolarity Glycerol Mitogen-Activated Protein Kinases in Promoting Cell Wall Damage and Caspofungin Tolerance. mBio 2020; 11:mBio.02962-19. [PMID: 32019798 PMCID: PMC7002344 DOI: 10.1128/mbio.02962-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Aspergillus fumigatus is an opportunistic human pathogen causing allergic reactions or systemic infections, such as invasive pulmonary aspergillosis in immunocompromised patients. The mitogen-activated protein kinase (MAPK) signaling pathways are essential for fungal adaptation to the human host. Fungal cell survival, fungicide tolerance, and virulence are highly dependent on the organization, composition, and function of the cell wall. Upon cell wall stress, MAPKs phosphorylate multiple target proteins involved in the remodeling of the cell wall. Here, we investigate the global phosphoproteome of the ΔsakA and ΔmpkCA. fumigatus and high-osmolarity glycerol (HOG) pathway MAPK mutants upon cell wall damage. This showed the involvement of the HOG pathway and identified novel protein kinases and transcription factors, which were confirmed by fungal genetics to be involved in promoting tolerance of cell wall damage. Our results provide understanding of how fungal signal transduction networks modulate the cell wall. This may also lead to the discovery of new fungicide drug targets to impact fungal cell wall function, fungicide tolerance, and virulence. The filamentous fungus Aspergillus fumigatus can cause a distinct set of clinical disorders in humans. Invasive aspergillosis (IA) is the most common life-threatening fungal disease of immunocompromised humans. The mitogen-activated protein kinase (MAPK) signaling pathways are essential to the adaptation to the human host. Fungal cell survival is highly dependent on the organization, composition, and function of the cell wall. Here, an evaluation of the global A. fumigatus phosphoproteome under cell wall stress caused by the cell wall-damaging agent Congo red (CR) revealed 485 proteins potentially involved in the cell wall damage response. Comparative phosphoproteome analyses with the ΔsakA, ΔmpkC, and ΔsakA ΔmpkC mutant strains from the osmotic stress MAPK cascades identify their additional roles during the cell wall stress response. Our phosphoproteomics allowed the identification of novel kinases and transcription factors (TFs) involved in osmotic stress and in the cell wall integrity (CWI) pathway. Our global phosphoproteome network analysis showed an enrichment for protein kinases, RNA recognition motif domains, and the MAPK signaling pathway. In contrast to the wild-type strain, there is an overall decrease of differentially phosphorylated kinases and phosphatases in ΔsakA, ΔmpkC, and ΔsakA ΔmpkC mutants. We constructed phosphomutants for the phosphorylation sites of several proteins differentially phosphorylated in the wild-type and mutant strains. For all the phosphomutants, there is an increase in the sensitivity to cell wall-damaging agents and a reduction in the MpkA phosphorylation upon CR stress, suggesting these phosphosites could be important for the MpkA modulation and CWI pathway regulation.
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9
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Azole resistance mechanisms in Aspergillus: update and recent advances. Int J Antimicrob Agents 2020; 55:105807. [DOI: 10.1016/j.ijantimicag.2019.09.011] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 09/05/2019] [Accepted: 09/15/2019] [Indexed: 12/11/2022]
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10
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Fabri JHTM, Rocha MC, Malavazi I. Overview of the Interplay Between Cell Wall Integrity Signaling Pathways and Membrane Lipid Biosynthesis in Fungi: Perspectives for Aspergillus fumigatus. Curr Protein Pept Sci 2019; 21:265-283. [PMID: 31284857 DOI: 10.2174/1389203720666190705164203] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 06/10/2019] [Accepted: 06/13/2019] [Indexed: 11/22/2022]
Abstract
The cell wall (CW) and plasma membrane are fundamental structures that define cell shape and support different cellular functions. In pathogenic fungi, such as Aspegillus fumigatus, they not only play structural roles but are also important for virulence and immune recognition. Both the CW and the plasma membrane remain as attractive drug targets to treat fungal infections, such as the Invasive Pulmonary Aspergillosis (IPA), a disease associated with high morbimortality in immunocompromised individuals. The low efficiency of echinocandins that target the fungal CW biosynthesis, the occurrence of environmental isolates resistant to azoles such as voriconazole and the known drawbacks associated with amphotericin toxicity foster the urgent need for fungal-specific drugable targets and/or more efficient combinatorial therapeutic strategies. Reverse genetic approaches in fungi unveil that perturbations of the CW also render cells with increased susceptibility to membrane disrupting agents and vice-versa. However, how the fungal cells simultaneously cope with perturbation in CW polysaccharides and cell membrane proteins to allow morphogenesis is scarcely known. Here, we focus on current information on how the main signaling pathways that maintain fungal cell wall integrity, such as the Cell Wall Integrity and the High Osmolarity Glycerol pathways, in different species often cross-talk to regulate the synthesis of molecules that comprise the plasma membrane, especially sphingolipids, ergosterol and phospholipids to promote functioning of both structures concomitantly and thus, cell viability. We propose that the conclusions drawn from other organisms are the foundations to point out experimental lines that can be endeavored in A. fumigatus.
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Affiliation(s)
| | - Marina C Rocha
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, Brazil
| | - Iran Malavazi
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, Brazil
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11
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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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12
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Chelius CL, Ribeiro LFC, Huso W, Kumar J, Lincoln S, Tran B, Goo YA, Srivastava R, Harris SD, Marten MR. Phosphoproteomic and transcriptomic analyses reveal multiple functions for Aspergillus nidulans MpkA independent of cell wall stress. Fungal Genet Biol 2019; 125:1-12. [PMID: 30639305 DOI: 10.1016/j.fgb.2019.01.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 12/18/2018] [Accepted: 01/04/2019] [Indexed: 12/17/2022]
Abstract
The protein kinase MpkA plays a prominent role in the cell wall integrity signaling (CWIS) pathway, acting as the terminal MAPK activating expression of genes which encode cell wall biosynthetic enzymes and other repair functions. Numerous studies focus on MpkA function during cell wall perturbation. Here, we focus on the role MpkA plays outside of cell wall stress, during steady state growth. In an effort to seek other, as yet unknown, connections to this pathway, an mpkA deletion mutant (ΔmpkA) was subjected to phosphoproteomic and transcriptomic analysis. When compared to the control (isogenic parent of ΔmpkA), there is strong evidence suggesting MpkA is involved with maintaining cell wall strength, branching regulation, and the iron starvation pathway, among others. Particle-size analysis during shake flask growth revealed ΔmpkA mycelia were about 4 times smaller than the control strain and more than 90 cell wall related genes show significantly altered expression levels. The deletion mutant had a significantly higher branching rate than the control and phosphoproteomic results show putative branching-regulation proteins, such as CotA, LagA, and Cdc24, have a significantly different level of phosphorylation. When grown in iron limited conditions, ΔmpkA had no difference in growth rate or production of siderophores, whereas the control strain showed decreased growth rate and increased siderophore production. Transcriptomic data revealed over 25 iron related genes with altered transcript levels. Results suggest MpkA is involved with regulation of broad cellular functions in the absence of stress.
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Affiliation(s)
- Cynthia L Chelius
- Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland Baltimore County, Baltimore, MD 21250, United States
| | - Liliane F C Ribeiro
- Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland Baltimore County, Baltimore, MD 21250, United States
| | - Walker Huso
- Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland Baltimore County, Baltimore, MD 21250, United States
| | - Jyothi Kumar
- Center for Plant Science Innovation and Department of Plant Pathology, University of Nebraska-Lincoln, Lincoln, NE 68588, United States
| | - Stephen Lincoln
- Department of Chemical and Biomolecular Engineering, University of Connecticut, Storrs, CT 06269, United States
| | - Bao Tran
- Mass Spectrometry Center, University of Maryland School of Pharmacy, Baltimore, MD, 21201, United States
| | - Young Ah Goo
- Mass Spectrometry Center, University of Maryland School of Pharmacy, Baltimore, MD, 21201, United States
| | - Ranjan Srivastava
- Department of Chemical and Biomolecular Engineering, University of Connecticut, Storrs, CT 06269, United States
| | - Steven D Harris
- Center for Plant Science Innovation and Department of Plant Pathology, University of Nebraska-Lincoln, Lincoln, NE 68588, United States
| | - Mark R Marten
- Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland Baltimore County, Baltimore, MD 21250, United States.
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13
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Rocha MC, Santos CA, Malavazi I. The Regulatory Function of the Molecular Chaperone Hsp90 in the Cell Wall Integrity of Pathogenic Fungi. CURR PROTEOMICS 2018. [DOI: 10.2174/1570164615666180820155807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Different signaling cascades including the Cell Wall Integrity (CWI), the High Osmolarity Glycerol (HOG) and the Ca2+/calcineurin pathways control the cell wall biosynthesis and remodeling in fungi. Pathogenic fungi, such as Aspergillus fumigatus and Candida albicans, greatly rely on these signaling circuits to cope with different sources of stress, including the cell wall stress evoked by antifungal drugs and the host’s response during infection. Hsp90 has been proposed as an important regulatory protein and an attractive target for antifungal therapy since it stabilizes major effector proteins that act in the CWI, HOG and Ca2+/calcineurin pathways. Data from the human pathogen C. albicans have provided solid evidence that loss-of-function of Hsp90 impairs the evolution of resistance to azoles and echinocandin drugs. In A. fumigatus, Hsp90 is also required for cell wall integrity maintenance, reinforcing a coordinated function of the CWI pathway and this essential molecular chaperone. In this review, we focus on the current information about how Hsp90 impacts the aforementioned signaling pathways and consequently the homeostasis and maintenance of the cell wall, highlighting this cellular event as a key mechanism underlying antifungal therapy based on Hsp90 inhibition.
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Affiliation(s)
- Marina Campos Rocha
- Departmento de Genetica e Evolucao, Centro de Ciencias Biologicas e da Saude, Universidade Federal de Sao Carlos, Sao Carlos, Brazil
| | - Camilla Alves Santos
- Departmento de Genetica e Evolucao, Centro de Ciencias Biologicas e da Saude, Universidade Federal de Sao Carlos, Sao Carlos, Brazil
| | - Iran Malavazi
- Departmento de Genetica e Evolucao, Centro de Ciencias Biologicas e da Saude, Universidade Federal de Sao Carlos, Sao Carlos, Brazil
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14
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Szalewski DA, Hinrichs VS, Zinniel DK, Barletta RG. The pathogenicity ofAspergillus fumigatus, drug resistance, and nanoparticle delivery. Can J Microbiol 2018; 64:439-453. [DOI: 10.1139/cjm-2017-0749] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The genus Aspergillus includes fungal species that cause major health issues of significant economic importance. These microorganisms are also the culprit for production of carcinogenic aflatoxins in grain storages, contaminating crops, and economically straining the production process. Aspergillus fumigatus is a very important pathogenic species, being responsible for high human morbidity and mortality on a global basis. The prevalence of these infections in immunosuppressed individuals is on the rise, and physicians struggle with the diagnosis of these deadly pathogens. Several virulence determinants facilitate fungal invasion and evasion of the host immune response. Metabolic functions are also important for virulence and drug resistance, since they allow fungi to obtain nutrients for their own survival and growth. Following a positive diagnostic identification, mortality rates remain high due, in part, to emerging resistance to frequently used antifungal drugs. In this review, we discuss the role of the main virulence, drug target, and drug resistance determinants. We conclude with the review of new technologies being developed to treat aspergillosis. In particular, microsphere and nanoparticle delivery systems are discussed in the context of improving drug bioavailability. Aspergillus will likely continue to cause problematic infections in immunocompromised patients, so it is imperative to improve treatment options.
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Affiliation(s)
- David A. Szalewski
- Department of Biological Systems Engineering, University of Nebraska, Lincoln, NE 68583-0726, USA
- Department of Microbiology, University of Nebraska, Lincoln, NE 68588-0664, USA
| | - Victoria S. Hinrichs
- College of Agricultural Sciences and Natural Resources, University of Nebraska, Lincoln, NE 68583-0702, USA
| | - Denise K. Zinniel
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska, Lincoln, NE 68583-0905, USA
| | - Raúl G. Barletta
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska, Lincoln, NE 68583-0905, USA
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15
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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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16
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Desoubeaux G, Cray C. Rodent Models of Invasive Aspergillosis due to Aspergillus fumigatus: Still a Long Path toward Standardization. Front Microbiol 2017; 8:841. [PMID: 28559881 PMCID: PMC5432554 DOI: 10.3389/fmicb.2017.00841] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 04/24/2017] [Indexed: 01/09/2023] Open
Abstract
Invasive aspergillosis has been studied in laboratory by the means of plethora of distinct animal models. They were developed to address pathophysiology, therapy, diagnosis, or miscellaneous other concerns associated. However, there are great discrepancies regarding all the experimental variables of animal models, and a thorough focus on them is needed. This systematic review completed a comprehensive bibliographic analysis specifically-based on the technical features of rodent models infected with Aspergillus fumigatus. Out the 800 articles reviewed, it was shown that mice remained the preferred model (85.8% of the referenced reports), above rats (10.8%), and guinea pigs (3.8%). Three quarters of the models involved immunocompromised status, mainly by steroids (44.4%) and/or alkylating drugs (42.9%), but only 27.7% were reported to receive antibiotic prophylaxis to prevent from bacterial infection. Injection of spores (30.0%) and inhalation/deposition into respiratory airways (66.9%) were the most used routes for experimental inoculation. Overall, more than 230 distinct A. fumigatus strains were used in models. Of all the published studies, 18.4% did not mention usage of any diagnostic tool, like histopathology or mycological culture, to control correct implementation of the disease and to measure outcome. In light of these findings, a consensus discussion should be engaged to establish a minimum standardization, although this may not be consistently suitable for addressing all the specific aspects of invasive aspergillosis.
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Affiliation(s)
- Guillaume Desoubeaux
- Division of Comparative Pathology, Department of Pathology and Laboratory Medicine, Miller School of Medicine, University of MiamiMiami, FL, USA.,Service de Parasitologie-Mycologie-Médecine tropicale, Centre Hospitalier Universitaire de ToursTours, France.,Centre d'Etude des Pathologies Respiratoires (CEPR) Institut National de la Santé et de la Recherche Médicale U1100/Équipe 3, Université François-RabelaisTours, France
| | - Carolyn Cray
- Division of Comparative Pathology, Department of Pathology and Laboratory Medicine, Miller School of Medicine, University of MiamiMiami, FL, USA
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17
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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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18
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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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19
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Nano-LC-Q-TOF Analysis of Proteome Revealed Germination of Aspergillus flavus Conidia is Accompanied by MAPK Signalling and Cell Wall Modulation. Mycopathologia 2016; 181:769-786. [PMID: 27576557 DOI: 10.1007/s11046-016-0056-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 08/23/2016] [Indexed: 10/21/2022]
Abstract
Aspergillus flavus is the second most leading cause of aspergillosis. The ability of A. flavus to adapt within the host environment is crtical for its colonization. Onset of germination of conidia is one of the crucial events; thus, in order to gain insight into A. flavus molecular adaptation while germination, protein profile of A. flavus was obtained. Approximately 82 % of conidia showed germination at 7 h; thus, samples were collected followed by protein extraction and subjected to nLC-Q-TOF mass spectrometer. Q-TOF data were analysed using Protein Lynx Global Services (PLGS 2.2.5) software. A total of 416 proteins were identified from UniProt Aspergillus species database. Orthologues of A. flavus was observed in A. fumigatus, A. niger, A. terreus, A. oryzae, etc. Proteins were further analysed in NCBI database, which showed that 27 proteins of A. flavus are not reported in UniProt and NCBI database. Functional characterization of proteins resulted majorly to cell wall synthesis and degradation, metabolisms (carbohydrate and amino acid metabolism), protein synthesis and degradation. Proteins/enzymes associated with aflatoxin biosynthesis were observed. We also observed Dicer-like proteins 1, 2 and autophagy-related proteins 2, 9, 18, 13, 11, 22. Expression of protein/enzymes associated with MAPK signalling pathway suggests their role during the germination process. Overall, the data present a catalogue of proteins/enzymes involved in the germination of A. flavus conidia and could also be applied to other Aspergillus species.
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20
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Dichtl K, Samantaray S, Wagener J. Cell wall integrity signalling in human pathogenic fungi. Cell Microbiol 2016; 18:1228-38. [DOI: 10.1111/cmi.12612] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 04/19/2016] [Accepted: 05/03/2016] [Indexed: 12/21/2022]
Affiliation(s)
- Karl Dichtl
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie; Ludwig-Maximilians-Universität München; 80336 Munich Germany
| | - Sweta Samantaray
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie; Ludwig-Maximilians-Universität München; 80336 Munich Germany
- Institute of Microbiology and Infection, School of Biosciences; University of Birmingham; Birmingham UK
| | - Johannes Wagener
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie; Ludwig-Maximilians-Universität München; 80336 Munich Germany
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21
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Sharafi G, Khosravi AR, Vahedi G, Yahyaraeyat R, Abbasi T. A comparative study of the timecourse of the expression of the thermo‑inducible HSP70 gene in clinical and environmental isolates of Aspergillus fumigatus. Mol Med Rep 2016; 13:4513-21. [PMID: 27035559 DOI: 10.3892/mmr.2016.5058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 03/15/2016] [Indexed: 11/06/2022] Open
Abstract
The internal environment within animals or humans provides different conditions to invading saprophytic fungal pathogens, requiring the differential regulation of genes in comparison to environmental conditions. Understanding the mechanisms by which pathogens regulate genes within the host may be key in determining pathogen behavior within the host and may additionally facilitate further investigation into novel therapeutic agents. The heat shock protein (HSP)70 gene and its associated proteins have been frequently reported to be among the most highly expressed and dominant proteins present within various locations at physiological temperatures. The present study examined relative gene expression levels of the HSP70 gene in Aspergillus fumigatus isolates from both clinical and environmental origins, at a range of temperature points (20, 30, 37 and 42˚C) over five days, using reverse transcription‑quantitative polymerase chain reaction, comparing with a standard A. fumigatus strain incubated at 25˚C. The results indicated a differential gene expression pattern for the environmental and clinical isolates. During the five days, the HSP70 expression levels in the clinical samples were higher than in the environmental samples. However, the difference in the expression levels between the two groups at 42˚C was reduced. The mean HSP70 expression level over the five incubation days demonstrated a gradual and continual increasing trend by temperature elevation in both groups at 30, 37 and 42˚C, however, at 20˚C both groups demonstrated reduced expression. The temperature shift from 20 to 42˚C resulted in HSP70 induction and up to a 10‑ and 8.6‑fold change in HSP70 expression levels on the fifth day of incubation in the clinical and environmental groups, respectively. In conclusion, incubation at 37 and 42˚C resulted in the highest expression levels in both experimental groups, with these temperature points important for the induction of HSP70 expression in A. fumigatus.
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Affiliation(s)
- Golnaz Sharafi
- Mycology Research Center, Faculty of Veterinary Medicine, University of Tehran, Tehran 1419963111, Iran
| | - Ali Reza Khosravi
- Mycology Research Center, Faculty of Veterinary Medicine, University of Tehran, Tehran 1419963111, Iran
| | - Ghasem Vahedi
- Mycology Research Center, Faculty of Veterinary Medicine, University of Tehran, Tehran 1419963111, Iran
| | - Ramak Yahyaraeyat
- Mycology Research Center, Faculty of Veterinary Medicine, University of Tehran, Tehran 1419963111, Iran
| | - Teimur Abbasi
- Faculty of Dentistry, Tabriz University of Medical Sciences, Tabriz 5166614711, Iran
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22
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The contribution of Aspergillus fumigatus stress responses to virulence and antifungal resistance. J Microbiol 2016; 54:243-53. [PMID: 26920884 DOI: 10.1007/s12275-016-5510-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 10/21/2015] [Accepted: 10/22/2015] [Indexed: 10/22/2022]
Abstract
Invasive aspergillosis has emerged as one of the most common life-threatening fungal disease of humans. The emergence of antifungal resistant pathogens represents a current and increasing threat to society. In turn, new strategies to combat fungal infection are urgently required. Fungal adaptations to stresses experienced within the human host are a prerequisite for the survival and virulence strategies of the pathogen. Here, we review the latest information on the signalling pathways in Aspergillus fumigatus that contribute to stress adaptations and virulence, while highlighting their potential as targets for the development of novel combinational antifungal therapies.
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23
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Neubauer M, Zhu Z, Penka M, Helmschrott C, Wagener N, Wagener J. Mitochondrial dynamics in the pathogenic mold Aspergillus fumigatus: therapeutic and evolutionary implications. Mol Microbiol 2015; 98:930-45. [PMID: 26272083 DOI: 10.1111/mmi.13167] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/12/2015] [Indexed: 12/26/2022]
Abstract
Mitochondria within eukaryotic cells continuously fuse and divide. This phenomenon is called mitochondrial dynamics and crucial for mitochondrial function and integrity. We performed a comprehensive analysis of mitochondrial dynamics in the pathogenic mold Aspergillus fumigatus. Phenotypic characterization of respective mutants revealed the general essentiality of mitochondrial fusion for mitochondrial genome maintenance and the mold's viability. Surprisingly, it turned out that the mitochondrial rhomboid protease Pcp1 and its processing product, s-Mgm,1 which are crucial for fusion in yeast, are dispensable for fusion, mtDNA maintenance and viability in A. fumigatus. In contrast, mitochondrial fission mutants show drastically reduced growth and sporulation rates and increased heat susceptibility. However, reliable inheritance of mitochondria to newly formed conidia is ensured. Strikingly, mitochondrial fission mutants show a significant and growth condition-dependent increase in azole resistance. Parallel disruption of fusion in a fission mutant partially rescues growth and sporulation defects and further increases the azole resistance phenotype. Taken together, our results indicate an emerging dispensability of the mitochondrial rhomboid protease function in mitochondrial fusion, the suitability of mitochondrial fusion machinery as antifungal target and the involvement of mitochondrial dynamics in azole susceptibility.
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Affiliation(s)
- Michael Neubauer
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Ludwig-Maximilians-Universität München, 80336, Munich, Germany
| | - Zhaojun Zhu
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Ludwig-Maximilians-Universität München, 80336, Munich, Germany
| | - Mirjam Penka
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Ludwig-Maximilians-Universität München, 80336, Munich, Germany
| | - Christoph Helmschrott
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Ludwig-Maximilians-Universität München, 80336, Munich, Germany
| | - Nikola Wagener
- Biozentrum, Ludwig-Maximilians-Universität München, 82152, Martinsried, Germany
| | - Johannes Wagener
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Ludwig-Maximilians-Universität München, 80336, Munich, Germany
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24
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Rocha MC, de Godoy KF, de Castro PA, Hori JI, Bom VLP, Brown NA, da Cunha AF, Goldman GH, Malavazi I. The Aspergillus fumigatus pkcA G579R Mutant Is Defective in the Activation of the Cell Wall Integrity Pathway but Is Dispensable for Virulence in a Neutropenic Mouse Infection Model. PLoS One 2015; 10:e0135195. [PMID: 26295576 PMCID: PMC4546635 DOI: 10.1371/journal.pone.0135195] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 07/19/2015] [Indexed: 12/03/2022] Open
Abstract
Aspergillus fumigatus is an opportunistic human pathogen, which causes the life-threatening disease, invasive pulmonary aspergillosis. In fungi, cell wall homeostasis is controlled by the conserved Cell Wall Integrity (CWI) pathway. In A. fumigatus this signaling cascade is partially characterized, but the mechanisms by which it is activated are not fully elucidated. In this study we investigated the role of protein kinase C (PkcA) in this signaling cascade. Our results suggest that pkcA is an essential gene and is activated in response to cell wall stress. Subsequently, we constructed and analyzed a non-essential A. fumigatus pkcAG579R mutant, carrying a Gly579Arg substitution in the PkcA C1B regulatory domain. The pkcAG579R mutation has a reduced activation of the downstream Mitogen-Activated Protein Kinase, MpkA, resulting in the altered expression of genes encoding cell wall-related proteins, markers of endoplasmic reticulum stress and the unfolded protein response. Furthermore, PkcAG579R is involved in the formation of proper conidial architecture and protection to oxidative damage. The pkcAG579R mutant elicits increased production of TNF-α and phagocytosis but it has no impact on virulence in a murine model of invasive pulmonary aspergillosis. These results highlight the importance of PkcA to the CWI pathway but also indicated that additional regulatory circuits may be involved in the biosynthesis and/or reinforcement of the A. fumigatus cell wall during infection.
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Affiliation(s)
- 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
| | - Krissia Franco de Godoy
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | - Patrícia Alves de Castro
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Juliana Issa Hori
- Departamento de Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Vinícius Leite Pedro Bom
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Neil Andrew Brown
- Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, Herts, United Kingdom
| | - Anderson Ferreira da Cunha
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | - Gustavo Henrique Goldman
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol, Campinas, São Paulo, 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
- * E-mail:
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Hitting the caspofungin salvage pathway of human-pathogenic fungi with the novel lasso peptide humidimycin (MDN-0010). Antimicrob Agents Chemother 2015; 59:5145-53. [PMID: 26055366 DOI: 10.1128/aac.00683-15] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 05/30/2015] [Indexed: 01/26/2023] Open
Abstract
Fungal infections have increased dramatically in the last 2 decades, and fighting infectious diseases requires innovative approaches such as the combination of two drugs acting on different targets or even targeting a salvage pathway of one of the drugs. The fungal cell wall biosynthesis is inhibited by the clinically used antifungal drug caspofungin. This antifungal activity has been found to be potentiated by humidimycin, a new natural product identified from the screening of a collection of 20,000 microbial extracts, which has no major effect when used alone. An analysis of transcriptomes and selected Aspergillus fumigatus mutants indicated that humidimycin affects the high osmolarity glycerol response pathway. By combining humidimycin and caspofungin, a strong increase in caspofungin efficacy was achieved, demonstrating that targeting different signaling pathways provides an excellent basis to develop novel anti-infective strategies.
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Valiante V, Macheleidt J, Föge M, Brakhage AA. The Aspergillus fumigatus cell wall integrity signaling pathway: drug target, compensatory pathways, and virulence. Front Microbiol 2015; 6:325. [PMID: 25932027 PMCID: PMC4399325 DOI: 10.3389/fmicb.2015.00325] [Citation(s) in RCA: 130] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 03/31/2015] [Indexed: 01/06/2023] Open
Abstract
Aspergillus fumigatus is the most important airborne fungal pathogen, causing severe infections with invasive growth in immunocompromised patients. The fungal cell wall (CW) prevents the cell from lysing and protects the fungus against environmental stress conditions. Because it is absent in humans and because of its essentiality, the fungal CW is a promising target for antifungal drugs. Nowadays, compounds acting on the CW, i.e., echinocandin derivatives, are used to treat A. fumigatus infections. However, studies demonstrating the clinical effectiveness of echinocandins in comparison with antifungals currently recommended for first-line treatment of invasive aspergillosis are still lacking. Therefore, it is important to elucidate CW biosynthesis pathways and their signal transduction cascades, which potentially compensate the inhibition caused by CW- perturbing compounds. Like in other fungi, the central core of the cell wall integrity (CWI) signaling pathway in A. fumigatus is composed of three mitogen activated protein kinases. Deletion of these genes resulted in severely enhanced sensitivity of the mutants against CW-disturbing compounds and in drastic alterations of the fungal morphology. Additionally, several cross-talk interactions between the CWI pathways and other signaling pathways are emerging, raising the question about their role in the CW compensatory mechanisms. In this review we focused on recent advances in understanding the CWI signaling pathway in A. fumigatus and its role during drug stress response and virulence.
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Affiliation(s)
- Vito Valiante
- Molecular Biotechnology of Natural Products, Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute Jena, Germany
| | - Juliane Macheleidt
- Molecular Biotechnology of Natural Products, Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute Jena, Germany
| | - Martin Föge
- Molecular Biotechnology of Natural Products, Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute Jena, Germany ; Department of Microbiology and Molecular Biology, Institute of Microbiology, Friedrich Schiller University Jena, Germany
| | - Axel A Brakhage
- Molecular Biotechnology of Natural Products, Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute Jena, Germany ; Department of Microbiology and Molecular Biology, Institute of Microbiology, Friedrich Schiller University Jena, Germany
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27
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Ding Z, Li M, Sun F, Xi P, Sun L, Zhang L, Jiang Z. Mitogen-activated protein kinases are associated with the regulation of physiological traits and virulence in Fusarium oxysporum f. sp. cubense. PLoS One 2015; 10:e0122634. [PMID: 25849862 PMCID: PMC4388850 DOI: 10.1371/journal.pone.0122634] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 02/23/2015] [Indexed: 01/09/2023] Open
Abstract
Fusarium oxysporum f. sp. cubense (FOC) is an important soil-borne fungal pathogen causing devastating vascular wilt disease of banana plants and has become a great concern threatening banana production worldwide. However, little information is known about the molecular mechanisms that govern the expression of virulence determinants of this important fungal pathogen. In this study, we showed that null mutation of three mitogen-activated protein (MAP) kinase genes, designated as FoSlt2, FoMkk2 and FoBck1, respectively, led to substantial attenuation in fungal virulence on banana plants. Transcriptional analysis revealed that the MAP kinase signaling pathway plays a key role in regulation of the genes encoding production of chitin, peroxidase, beauvericin and fusaric acid. Biochemical analysis further confirmed the essential role of MAP kinases in modulating the production of fusaric acid, which was a crucial phytotoxin in accelerating development of Fusarium wilt symptoms in banana plants. Additionally, we found that the MAP kinase FoSlt2 was required for siderophore biosynthesis under iron-depletion conditions. Moreover, disruption of the MAP kinase genes resulted in abnormal hypha and increased sensitivity to Congo Red, Calcofluor White and H2O2. Taken together, these results depict the critical roles of MAP kinases in regulation of FOC physiology and virulence.
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Affiliation(s)
- Zhaojian Ding
- Department of Plant Pathology, South China Agricultural University, Guangzhou 510642, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China
| | - Minhui Li
- Department of Plant Pathology, South China Agricultural University, Guangzhou 510642, China
| | - Fei Sun
- Department of Plant Pathology, South China Agricultural University, Guangzhou 510642, China
| | - Pinggen Xi
- Department of Plant Pathology, South China Agricultural University, Guangzhou 510642, China
| | - Longhua Sun
- Department of Plant Pathology, South China Agricultural University, Guangzhou 510642, China
| | - Lianhui Zhang
- Department of Plant Pathology, South China Agricultural University, Guangzhou 510642, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China
- * E-mail: (ZDJ); (LHZ)
| | - Zide Jiang
- Department of Plant Pathology, South China Agricultural University, Guangzhou 510642, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China
- * E-mail: (ZDJ); (LHZ)
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Wang J, Zhou H, Lu H, Du T, Luo Y, Wilson IBH, Jin C. Kexin-like endoprotease KexB is required for N-glycan processing, morphogenesis and virulence in Aspergillus fumigatus. Fungal Genet Biol 2015; 76:57-69. [PMID: 25687931 DOI: 10.1016/j.fgb.2015.02.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 02/05/2015] [Accepted: 02/06/2015] [Indexed: 11/18/2022]
Abstract
Kexin-like proteins belong to the subtilisin-like family of the proteinases that cleave secretory proproteins to their active forms. Several fungal kexin-like proteins have been investigated. The mutants lacking of kexin-like protein display strong phenotypes such as cell wall defect, abnormal polarity, and, in case of Candida albicans, diminished virulence. However, only several proteins have been confirmed as the substrates of kexin-like proteases in these fungal species. It still remains unclear how kexin-like proteins contribute to the morphogenesis in these fungal species. In this study, a kexB-null mutant of the human opportunistic fungal pathogen Aspergillus fumigatus was constructed and analyzed. The ΔkexB mutant showed retarded growth, temperature-sensitive cell wall defect, reduced conidia formation, and abnormal polarity. Biochemical analyses revealed that deletion of the kexB gene resulted in impaired N-glycan processing, activation of the MpkA-dependent cell wall integrity signaling pathway, and ER-stress. Results from in vivo assays demonstrated that the mutant exhibited an attenuated virulence in immunecompromised mice. Based on our results, the kexin-like endoprotease KexB was involved in the N-glycan processing, which provides a novel insight to understand how kexin-like protein affects the cell-wall modifying enzymes and therefore morphogenesis in fungi.
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Affiliation(s)
- Jingyang Wang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, China
| | - Hui Zhou
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Hua Lu
- 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
| | - Yuanming Luo
- 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
| | - Cheng Jin
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
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29
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The molecular mechanism of azole resistance in Aspergillus fumigatus: from bedside to bench and back. J Microbiol 2015; 53:91-9. [PMID: 25626363 DOI: 10.1007/s12275-015-5014-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 01/13/2015] [Indexed: 10/24/2022]
Abstract
The growing use of immunosuppressive therapies has resulted in a dramatic increased incidence of invasive fungal infections (IFIs) caused by Aspergillus fumigatus, a common pathogen, and is also associated with a high mortality rate. Azoles are the primary guideline-recommended therapy agents for first-line treatment and prevention of IFIs. However, increased azole usage in medicinal and agricultural settings has caused azole-resistant isolates to repeatedly emerge in the environment, resulting in a significant threat to human health. In this review, we present and summarize current research on the resistance mechanisms of azoles in A. fumigatus as well as efficient susceptibility testing methods. Moreover, we analyze and discuss the putative clinical (bedside) indication of these findings from bench work.
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30
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Li A, Zhang M, Wang Y, Li D, Liu X, Tao K, Ye W, Wang Y. PsMPK1, an SLT2-type mitogen-activated protein kinase, is required for hyphal growth, zoosporogenesis, cell wall integrity, and pathogenicity in Phytophthora sojae. Fungal Genet Biol 2014; 65:14-24. [PMID: 24480463 DOI: 10.1016/j.fgb.2014.01.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 01/11/2014] [Accepted: 01/13/2014] [Indexed: 12/13/2022]
Abstract
Mitogen-activated protein kinases (MAPKs) play important roles in the regulation of vegetative and pathogenic growth in plant pathogens. Here, we identified an SLT2-type MAP kinase in Phytophthora sojae, PsMPK1, which was transcriptionally induced in sporulating hyphae and the early stages of infection. Silencing of PsMPK1 caused defects in growth and zoosporogenesis, and increased hyphal swellings after the induction of sporangia formation, along with increasing hypersensitivity to cell wall-degrading enzymes. Transmission electron microscopy showed that the cell wall of PsMPK1-silenced mutants was also deleteriously affected. A dark outermost layer in the cell walls disappeared in the mutants, and an additional layer of the mutant cell wall that was deposited abnormally inside an inner bright layer appeared nonhomogeneous and rough compared to the wild type. Pathogenicity assays showed that PsMPK1-silenced transformants lost their pathogenicity on susceptible soybean host plants and triggered stronger cell death. Overall, PsMPK1 is involved in growth, differentiation, cell wall integrity, and pathogenicity in P. sojae.
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Affiliation(s)
- Aining Li
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Meng Zhang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Yonglin Wang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Delong Li
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Xiaoyun Liu
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Kai Tao
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Wenwu Ye
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Yuanchao Wang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China.
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31
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Minenko E, Vogel RF, Niessen L. Significance of the class II hydrophobin FgHyd5p for the life cycle of Fusarium graminearum. Fungal Biol 2014; 118:385-93. [PMID: 24742833 DOI: 10.1016/j.funbio.2014.02.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 02/03/2014] [Accepted: 02/15/2014] [Indexed: 11/28/2022]
Abstract
Hydrophobins are small secreted proteins ubiquitously found in filamentous fungi. Some hydrophobins were shown to have functions in fungal development, while others lack known function. Class II hydrophobins from Fusarium graminearum and Fusarium culmorum are characterized by formation of low stability aggregates and their solubility in organic solvents. They are economically relevant to the brewing industry because they can induce beer gushing. Since cellular functions of Hyd5p's are still unknown, we analyzed the influence of FgHyd5p on growth and morphology of F. graminearum using FgΔhyd5 knock-out mutants expressing sGFP under the control of the hyd5 promoter and compared them with the performance of the parent wild type strain. Results demonstrate that FgHyd5p does not affect the colony and hyphal morphology. FgHyd5p affects the hydrophobicity of aerial mycelia but had no obvious function in penetration of hyphae through the water air interface. The hydrophobin affects the morphology of conidia, but not their fitness. Different sources of carbon and nitrogen as well as different pH have no effect on the expression of the hyd5 gene, which was demonstrated to be expressed upon growth of F. graminearum on hydrophobic surfaces.
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32
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Guerriero G, Silvestrini L, Obersriebnig M, Salerno M, Pum D, Strauss J. Sensitivity of Aspergillus nidulans to the cellulose synthase inhibitor dichlobenil: insights from wall-related genes' expression and ultrastructural hyphal morphologies. PLoS One 2013; 8:e80038. [PMID: 24312197 PMCID: PMC3843659 DOI: 10.1371/journal.pone.0080038] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Accepted: 09/27/2013] [Indexed: 11/30/2022] Open
Abstract
The fungal cell wall constitutes an important target for the development of antifungal drugs, because of its central role in morphogenesis, development and determination of fungal-specific molecular features. Fungal walls are characterized by a network of interconnected glycoproteins and polysaccharides, namely α-, β-glucans and chitin. Cell walls promptly and dynamically respond to environmental stimuli by a signaling mechanism, which triggers, among other responses, modulations in wall biosynthetic genes’ expression. Despite the absence of cellulose in the wall of the model filamentous fungus Aspergillus nidulans, we found in this study that fungal growth, spore germination and morphology are affected by the addition of the cellulose synthase inhibitor dichlobenil. Expression analysis of selected genes putatively involved in cell wall biosynthesis, carried out at different time points of drug exposure (i.e. 0, 1, 3, 6 and 24 h), revealed increased expression for the putative mixed linkage β-1,3;1,4 glucan synthase celA together with the β-1,3-glucan synthase fksA and the Rho-related GTPase rhoA. We also compared these data with the response to Congo Red, a known plant/fungal drug affecting both chitin and cellulose biosynthesis. The two drugs exerted different effects at the cell wall level, as shown by gene expression analysis and the ultrastructural features observed through atomic force microscopy and scanning electron microscopy. Although the concentration of dichlobenil required to affect growth of A. nidulans is approximately 10-fold higher than that required to inhibit plant cellulose biosynthesis, our work for the first time demonstrates that a cellulose biosynthesis inhibitor affects fungal growth, changes fungal morphology and expression of genes connected to fungal cell wall biosynthesis.
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Affiliation(s)
- Gea Guerriero
- Department of Applied Genetics and Cell Biology, Fungal Genetics and Genomics Unit, University of Natural Resources and Life Sciences Vienna (BOKU), University and Research Center Campus Tulln-Technopol, Tulln/Donau, Austria
- * E-mail: (GG); (JS)
| | - Lucia Silvestrini
- Department of Applied Genetics and Cell Biology, Fungal Genetics and Genomics Unit, University of Natural Resources and Life Sciences Vienna (BOKU), University and Research Center Campus Tulln-Technopol, Tulln/Donau, Austria
| | - Michael Obersriebnig
- Institute of Wood Science and Technology, University of Natural Resources and Life Sciences Vienna (BOKU), University and Research Center Campus Tulln-Technopol, Tulln/Donau, Austria
| | - Marco Salerno
- Nanophysics Department, Istituto Italiano di Tecnologia, Genova, Italy
| | - Dietmar Pum
- Department of Nanobiotechnology, Institute for Biophysics, University of Natural Resources and Life Sciences Vienna (BOKU), Vienna, Austria
| | - Joseph Strauss
- Department of Applied Genetics and Cell Biology, Fungal Genetics and Genomics Unit, University of Natural Resources and Life Sciences Vienna (BOKU), University and Research Center Campus Tulln-Technopol, Tulln/Donau, Austria
- Health and Environment Department, Austrian Institute of Technology GmbH - AIT, University and Research Center Campus Tulln-Technopol, Tulln/Donau, Austria
- * E-mail: (GG); (JS)
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Grice CM, Bertuzzi M, Bignell EM. Receptor-mediated signaling in Aspergillus fumigatus. Front Microbiol 2013; 4:26. [PMID: 23430083 PMCID: PMC3576715 DOI: 10.3389/fmicb.2013.00026] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 02/01/2013] [Indexed: 11/15/2022] Open
Abstract
Aspergillus fumigatus is the most pathogenic species among the Aspergilli, and the major fungal agent of human pulmonary infection. To prosper in diverse ecological niches, Aspergilli have evolved numerous mechanisms for adaptive gene regulation, some of which are also crucial for mammalian infection. Among the molecules which govern such responses, integral membrane receptors are thought to be the most amenable to therapeutic modulation. This is due to the localization of these molecular sensors at the periphery of the fungal cell, and to the prevalence of small molecules and licensed drugs which target receptor-mediated signaling in higher eukaryotic cells. In this review we highlight the progress made in characterizing receptor-mediated environmental adaptation in A. fumigatus and its relevance for pathogenicity in mammals. By presenting a first genomic survey of integral membrane proteins in this organism, we highlight an abundance of putative seven transmembrane domain (7TMD) receptors, the majority of which remain uncharacterized. Given the dependency of A. fumigatus upon stress adaptation for colonization and infection of mammalian hosts, and the merits of targeting receptor-mediated signaling as an antifungal strategy, a closer scrutiny of sensory perception and signal transduction in this organism is warranted.
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Affiliation(s)
- C M Grice
- South Kensington Campus, Imperial College London London, UK
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34
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Role of the guanine nucleotide exchange factor Rom2 in cell wall integrity maintenance of Aspergillus fumigatus. EUKARYOTIC CELL 2012; 12:288-98. [PMID: 23264643 DOI: 10.1128/ec.00246-12] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Aspergillus fumigatus is a mold and the causal agent of invasive aspergillosis, a systemic disease with high lethality. Recently, we identified and functionally characterized three stress sensors implicated in the cell wall integrity (CWI) signaling of this pathogen, namely, Wsc1, Wsc3, and MidA. Here, we functionally characterize Rom2, a guanine nucleotide exchange factor with essential function for the cell wall integrity of A. fumigatus. A conditional rom2 mutant has severe growth defects under repressive conditions and incorporates all phenotypes of the three cell wall integrity sensor mutants, e.g., the echinocandin sensitivity of the Δwsc1 mutant and the Congo red, calcofluor white, and heat sensitivity of the ΔmidA mutant. Rom2 interacts with Rho1 and shows a similar intracellular distribution focused at the hyphal tips. Our results place Rom2 between the cell surface stress sensors Wsc1, Wsc3, MidA, and Rho1 and their downstream effector mitogen-activated protein (MAP) kinase module Bck1-Mkk2-MpkA.
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35
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Discovery of a HapE mutation that causes azole resistance in Aspergillus fumigatus through whole genome sequencing and sexual crossing. PLoS One 2012; 7:e50034. [PMID: 23226235 PMCID: PMC3511431 DOI: 10.1371/journal.pone.0050034] [Citation(s) in RCA: 148] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 10/15/2012] [Indexed: 01/10/2023] Open
Abstract
Azole compounds are the primary therapy for patients with diseases caused by Aspergillus fumigatus. However, prolonged treatment may cause resistance to develop, which is associated with treatment failure. The azole target cyp51A is a hotspot for mutations that confer phenotypic resistance, but in an increasing number of resistant isolates the underlying mechanism remains unknown. Here, we report the discovery of a novel resistance mechanism, caused by a mutation in the CCAAT-binding transcription factor complex subunit HapE. From one patient, four A. fumigatus isolates were serially collected. The last two isolates developed an azole resistant phenotype during prolonged azole therapy. Because the resistant isolates contained a wild type cyp51A gene and the isolates were isogenic, the complete genomes of the last susceptible isolate and the first resistant isolate (taken 17 weeks apart) were sequenced using Illumina technology to identify the resistance conferring mutation. By comparing the genome sequences to each other as well as to two A. fumigatus reference genomes, several potential non-synonymous mutations in protein-coding regions were identified, six of which could be confirmed by PCR and Sanger sequencing. Subsequent sexual crossing experiments showed that resistant progeny always contained a P88L substitution in HapE, while the presence of the other five mutations did not correlate with resistance in the progeny. Cloning the mutated hapE gene into the azole susceptible akuB(KU80) strain showed that the HapE P88L mutation by itself could confer the resistant phenotype. This is the first time that whole genome sequencing and sexual crossing strategies have been used to find the genetic basis of a trait of interest in A. fumigatus. The discovery may help understand alternate pathways for azole resistance in A. fumigatus with implications for the molecular diagnosis of resistance and drug discovery.
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36
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Dichtl K, Helmschrott C, Dirr F, Wagener J. Deciphering cell wall integrity signalling in Aspergillus fumigatus: identification and functional characterization of cell wall stress sensors and relevant Rho GTPases. Mol Microbiol 2012; 83:506-19. [DOI: 10.1111/j.1365-2958.2011.07946.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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37
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Prusinkiewicz MA, Farazkhorasani F, Dynes JJ, Wang J, Gough KM, Kaminskyj SGW. Proof-of-principle for SERS imaging of Aspergillus nidulans hyphae using in vivo synthesis of gold nanoparticles. Analyst 2012; 137:4934-42. [DOI: 10.1039/c2an35620a] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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38
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Jain R, Valiante V, Remme N, Docimo T, Heinekamp T, Hertweck C, Gershenzon J, Haas H, Brakhage AA. The MAP kinase MpkA controls cell wall integrity, oxidative stress response, gliotoxin production and iron adaptation in Aspergillus fumigatus. Mol Microbiol 2011; 82:39-53. [PMID: 21883519 PMCID: PMC3229709 DOI: 10.1111/j.1365-2958.2011.07778.x] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The saprophytic fungus Aspergillus fumigatus is the most important air-borne fungal pathogen. The cell wall of A. fumigatus has been studied intensively as a potential target for development of effective antifungal agents. A major role in maintaining cell wall integrity is played by the mitogen-activated protein kinase (MAPK) MpkA. To gain a comprehensive insight into this central signal transduction pathway, we performed a transcriptome analysis of the ΔmpkA mutant under standard and cell wall stress conditions. Besides genes involved in cell wall remodelling, protection against ROS and secondary metabolism such as gliotoxin, pyomelanin and pseurotin A, also genes involved in siderophore biosynthesis were regulated by MpkA. Consistently, northern and western blot analyses indicated that iron starvation triggers phosphorylation and thus activation of MpkA. Furthermore, localization studies indicated that MpkA accumulates in the nucleus under iron depletion. Hence, we report the first connection between a MAPK pathway and siderophore biosynthesis. The measurement of amino acid pools and of the pools of polyamines indicated that arginine was continuously converted into ornithine to fuel the siderophore pool in the ΔmpkA mutant strain. Based on our data, we propose that MpkA fine-tunes the balance between stress response and energy consuming cellular processes.
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Affiliation(s)
- Radhika Jain
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstrasse 11a, D-07745 Jena, Germany
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Shapiro RS, Robbins N, Cowen LE. Regulatory circuitry governing fungal development, drug resistance, and disease. Microbiol Mol Biol Rev 2011; 75:213-67. [PMID: 21646428 PMCID: PMC3122626 DOI: 10.1128/mmbr.00045-10] [Citation(s) in RCA: 384] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Pathogenic fungi have become a leading cause of human mortality due to the increasing frequency of fungal infections in immunocompromised populations and the limited armamentarium of clinically useful antifungal drugs. Candida albicans, Cryptococcus neoformans, and Aspergillus fumigatus are the leading causes of opportunistic fungal infections. In these diverse pathogenic fungi, complex signal transduction cascades are critical for sensing environmental changes and mediating appropriate cellular responses. For C. albicans, several environmental cues regulate a morphogenetic switch from yeast to filamentous growth, a reversible transition important for virulence. Many of the signaling cascades regulating morphogenesis are also required for cells to adapt and survive the cellular stresses imposed by antifungal drugs. Many of these signaling networks are conserved in C. neoformans and A. fumigatus, which undergo distinct morphogenetic programs during specific phases of their life cycles. Furthermore, the key mechanisms of fungal drug resistance, including alterations of the drug target, overexpression of drug efflux transporters, and alteration of cellular stress responses, are conserved between these species. This review focuses on the circuitry regulating fungal morphogenesis and drug resistance and the impact of these pathways on virulence. Although the three human-pathogenic fungi highlighted in this review are those most frequently encountered in the clinic, they represent a minute fraction of fungal diversity. Exploration of the conservation and divergence of core signal transduction pathways across C. albicans, C. neoformans, and A. fumigatus provides a foundation for the study of a broader diversity of pathogenic fungi and a platform for the development of new therapeutic strategies for fungal disease.
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Affiliation(s)
| | | | - Leah E. Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
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Hartmann T, Sasse C, Schedler A, Hasenberg M, Gunzer M, Krappmann S. Shaping the fungal adaptome--stress responses of Aspergillus fumigatus. Int J Med Microbiol 2011; 301:408-16. [PMID: 21565548 DOI: 10.1016/j.ijmm.2011.04.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Aspergillus fumigatus as prime pathogen to cause aspergillosis has evolved as a saprophyte, but is also able to infect and colonise immunocompromised hosts. Based on the 'dual use' hypothesis of fungal pathogenicity, general characteristics have to be considered as unspecific virulence determinants, among them stress adaptation capacities. The susceptible, warm-blooded mammalian host represents a specific ecological niche that poses several kinds of stress conditions to the fungus during the course of infection. Detailed knowledge about the cellular pathways and adaptive traits that have evolved in A. fumigatus to counteract situations of stress and varying environmental conditions is crucial for the identification of novel and specific antifungal targets. Comprehensive profiling data accompanied by mutant analyses have shed light on such stressors, and nutritional deprivation, oxidative stress, hypoxia, elevated temperature, alkaline pH, extensive secretion, and, in particular during treatment with antifungals, cell membrane perturbations appear to represent the major hazards A. fumigatus has to cope with during infection. Further efforts employing innovative approaches and advanced technologies will have to be made to expand our knowledge about the scope of the A. fumigatus adaptome that is relevant for disease.
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Affiliation(s)
- Thomas Hartmann
- Research Center for Infectious Diseases, Julius-Maximilians-University Würzburg, Germany
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Dichtl K, Ebel F, Dirr F, Routier FH, Heesemann J, Wagener J. Farnesol misplaces tip-localized Rho proteins and inhibits cell wall integrity signalling in Aspergillus fumigatus. Mol Microbiol 2010; 76:1191-204. [DOI: 10.1111/j.1365-2958.2010.07170.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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