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Balamurugan C, Steenwyk JL, Goldman GH, Rokas A. The evolution of the gliotoxin biosynthetic gene cluster in Penicillium fungi. G3 (BETHESDA, MD.) 2024; 14:jkae063. [PMID: 38507596 PMCID: PMC11075534 DOI: 10.1093/g3journal/jkae063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 12/27/2023] [Accepted: 03/11/2024] [Indexed: 03/22/2024]
Abstract
Fungi biosynthesize diverse secondary metabolites, small organic bioactive molecules with key roles in fungal ecology. Fungal secondary metabolites are often encoded by physically clustered genes known as biosynthetic gene clusters (BGCs). Fungi in the genus Penicillium produce a cadre of secondary metabolites, some of which are useful (e.g. the antibiotic penicillin and the cholesterol-lowering drug mevastatin) and others harmful (e.g. the mycotoxin patulin and the immunosuppressant gliotoxin) to human affairs. Fungal genomes often also encode resistance genes that confer protection against toxic secondary metabolites. Some Penicillium species, such as Penicillium decumbens, are known to produce gliotoxin, a secondary metabolite with known immunosuppressant activity. To investigate the evolutionary conservation of homologs of the gliotoxin BGC and of genes involved in gliotoxin resistance in Penicillium, we analyzed 35 Penicillium genomes from 23 species. Homologous, lesser fragmented gliotoxin BGCs were found in 12 genomes, mostly fragmented remnants of the gliotoxin BGC were found in 21 genomes, whereas the remaining 2 Penicillium genomes lacked the gliotoxin BGC altogether. In contrast, broad conservation of homologs of resistance genes that reside outside the BGC across Penicillium genomes was observed. Evolutionary rate analysis revealed that BGCs with higher numbers of genes evolve slower than BGCs with few genes, suggestive of constraint and potential functional significance or more recent decay. Gene tree-species tree reconciliation analyses suggested that the history of homologs in the gliotoxin BGC across the genus Penicillium likely involved multiple duplications, losses, and horizontal gene transfers. Our analyses suggest that genes encoded in BGCs can have complex evolutionary histories and be retained in genomes long after the loss of secondary metabolite biosynthesis.
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Affiliation(s)
- Charu Balamurugan
- Department of Biological Sciences, Vanderbilt University, VU Station B #35-1634, Nashville, TN 37235, USA
- Vanderbilt Evolutionary Studies Initiative, Vanderbilt University, Nashville, TN 37235, USA
| | - Jacob L Steenwyk
- Department of Biological Sciences, Vanderbilt University, VU Station B #35-1634, Nashville, TN 37235, USA
- Vanderbilt Evolutionary Studies Initiative, Vanderbilt University, Nashville, TN 37235, USA
- Howards Hughes Medical Institute and the Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Gustavo H Goldman
- Faculdade de Ciencias Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo CEP 14040-903, Brazil
| | - Antonis Rokas
- Department of Biological Sciences, Vanderbilt University, VU Station B #35-1634, Nashville, TN 37235, USA
- Vanderbilt Evolutionary Studies Initiative, Vanderbilt University, Nashville, TN 37235, USA
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2
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Guadarrama-Pérez V, Aguilar C, Porras-Sanjuanico A, Merino E, Ramírez OT, Barona-Gómez F, Palomares LA. Expression in CHO cells of a bacterial biosynthetic pathway producing a small non-ribosomal peptide aldehyde prevents proteolysis of recombinant proteins. Metab Eng 2024; 82:79-88. [PMID: 38290598 DOI: 10.1016/j.ymben.2024.01.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 12/19/2023] [Accepted: 01/21/2024] [Indexed: 02/01/2024]
Abstract
A significant problem during recombinant protein production is proteolysis. One of the most common preventive strategies is the addition of protease inhibitors, which has drawbacks, such as their short half-life and high cost, and their limited prevention of extracellular proteolysis. Actinomycetes produce the most commonly used inhibitors, which are non-ribosomal small aldehydic peptides. Previously, an unprecedented biosynthetic route involving a condensation-minus non-ribosomal peptide synthetase (NRPSs) and a tRNA utilizing enzyme (tRUE) was shown to direct the synthesis of one of these inhibitor peptides, livipeptin. Here, we show that expression of the livipeptin biosynthetic pathway encoded by the lvp genes in CHO cells resulted in the production of this metabolite with cysteine protease inhibitory activity, implying that mammalian tRNAs were recruited by the lvp system. CHO cells transiently expressing the biosynthetic pathway produced livipeptin without affecting cell growth or viability. Expression of the lvp system in CHO cells producing two model proteins, secreted alkaline phosphatase (hSeAP) and a monoclonal antibody, resulted in higher specific productivity with reduced proteolysis. We show for the first time that the expression of a bacterial biosynthetic pathway is functional in CHO cells, resulting in the efficient, low-cost synthesis of a protease inhibitor without adverse effects on CHO cells. This expands the field of metabolic engineering of mammalian cells by expressing the overwhelming diversity of actinomycetes biosynthetic pathways and opens a new option for proteolysis inhibition in bioprocess engineering.
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Affiliation(s)
- Violeta Guadarrama-Pérez
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología. Universidad Nacional Autónoma de México. Cuernavaca, Mor, 62210, México.
| | - César Aguilar
- Evolution of Metabolic Diversity Laboratory, Unidad de Genómica Avanzada (LANGEBIO), Cinvestav-IPN, Irapuato, Guanajuato, Mexico; Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA.
| | - Alberto Porras-Sanjuanico
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología. Universidad Nacional Autónoma de México. Cuernavaca, Mor, 62210, México.
| | - Enrique Merino
- Departamento de Microbiología Molecular. Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mor, 62210, Mexico.
| | - Octavio T Ramírez
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología. Universidad Nacional Autónoma de México. Cuernavaca, Mor, 62210, México.
| | - Francisco Barona-Gómez
- Evolution of Metabolic Diversity Laboratory, Unidad de Genómica Avanzada (LANGEBIO), Cinvestav-IPN, Irapuato, Guanajuato, Mexico; Institute of Biology, Leiden University, Leiden, 2333, BE, the Netherlands.
| | - Laura A Palomares
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología. Universidad Nacional Autónoma de México. Cuernavaca, Mor, 62210, México.
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3
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Lin SY, Oakley CE, Jenkinson CB, Chiang YM, Lee CK, Jones CG, Seidler PM, Nelson HM, Todd RB, Wang CCC, Oakley BR. A heterologous expression platform in Aspergillus nidulans for the elucidation of cryptic secondary metabolism biosynthetic gene clusters: discovery of the Aspergillus fumigatus sartorypyrone biosynthetic pathway. Chem Sci 2023; 14:11022-11032. [PMID: 37860661 PMCID: PMC10583710 DOI: 10.1039/d3sc02226a] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 06/26/2023] [Indexed: 10/21/2023] Open
Abstract
Aspergillus fumigatus is a serious human pathogen causing life-threatening Aspergillosis in immunocompromised patients. Secondary metabolites (SMs) play an important role in pathogenesis, but the products of many SM biosynthetic gene clusters (BGCs) remain unknown. In this study, we have developed a heterologous expression platform in Aspergillus nidulans, using a newly created genetic dereplication strain, to express a previously unknown BGC from A. fumigatus and determine its products. The BGC produces sartorypyrones, and we have named it the spy BGC. Analysis of targeted gene deletions by HRESIMS, NMR, and microcrystal electron diffraction (MicroED) enabled us to identify 12 products from the spy BGC. Seven of the compounds have not been isolated previously. We also individually expressed the polyketide synthase (PKS) gene spyA and demonstrated that it produces the polyketide triacetic acid lactone (TAL), a potentially important biorenewable platform chemical. Our data have allowed us to propose a biosynthetic pathway for sartorypyrones and related natural products. This work highlights the potential of using the A. nidulans heterologous expression platform to uncover cryptic BGCs from A. fumigatus and other species, despite the complexity of their secondary metabolomes.
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Affiliation(s)
- Shu-Yi Lin
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California Los Angeles CA 90089 USA
| | - C Elizabeth Oakley
- Department of Molecular Biosciences, University of Kansas 1200 Sunnyside Avenue Lawrence KS 66045 USA
| | - Cory B Jenkinson
- Department of Molecular Biosciences, University of Kansas 1200 Sunnyside Avenue Lawrence KS 66045 USA
| | - Yi-Ming Chiang
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California Los Angeles CA 90089 USA
| | - Ching-Kuo Lee
- School of Pharmacy, College of Pharmacy, Taipei Medical University Taipei 11031 Taiwan
| | - Christopher G Jones
- The Arnold and Mabel Beckman Laboratory of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology Pasadena California 91125 USA
| | - Paul M Seidler
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California Los Angeles CA 90089 USA
| | - Hosea M Nelson
- The Arnold and Mabel Beckman Laboratory of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology Pasadena California 91125 USA
| | - Richard B Todd
- Department of Plant Pathology, Kansas State University Manhattan KS 66506 USA
| | - Clay C C Wang
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California Los Angeles CA 90089 USA
- Department of Chemistry, University of Southern California Los Angeles CA 90089 USA
| | - Berl R Oakley
- Department of Molecular Biosciences, University of Kansas 1200 Sunnyside Avenue Lawrence KS 66045 USA
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4
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Kamath MM, Lightfoot JD, Adams EM, Kiser RM, Wells BL, Fuller KK. The Aspergillus fumigatus UPR is variably activated across nutrient and host environments and is critical for the establishment of corneal infection. PLoS Pathog 2023; 19:e1011435. [PMID: 37906600 PMCID: PMC10637725 DOI: 10.1371/journal.ppat.1011435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 11/10/2023] [Accepted: 10/14/2023] [Indexed: 11/02/2023] Open
Abstract
The Aspergillus fumigatus unfolded protein response (UPR) is a two-component relay consisting of the ER-bound IreA protein, which splices and activates the mRNA of the transcription factor HacA. Spliced hacA accumulates under conditions of acute ER stress in vitro, and UPR null mutants are hypovirulent in a murine model of invasive pulmonary infection. In this report, we demonstrate that a hacA deletion mutant (ΔhacA) is furthermore avirulent in a model of fungal keratitis, a corneal infection, and an important cause of ocular morbidity and unilateral blindness worldwide. Interestingly, we demonstrate that A. fumigatus hacA is spliced in infected lung samples, but not in the cornea, suggesting the amount of ER stress experienced by the fungus varies upon the host niche. To better understand how the UPR contributes to fungal cell biology across a spectrum of ER-stress levels, we employed transcriptomics on the wild-type and ΔhacA strains in glucose minimal media (low stress), glucose minimal media with dithiothreitol (high stress), and gelatin minimal media as a proxy for the nutrient stress encountered in the cornea (mid-level stress). These data altogether reveal a unique HacA-dependent transcriptome under each condition, suggesting that HacA activity is finely-tuned and required for proper fungal adaptation in each environment. Taken together, our results indicate that the fungal UPR could serve as an important antifungal target in the setting of both invasive pulmonary and corneal infections.
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Affiliation(s)
- Manali M. Kamath
- Department of Microbiology & Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Jorge D. Lightfoot
- Department of Microbiology & Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Emily M. Adams
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Ryan M. Kiser
- Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Becca L. Wells
- Department of Microbiology & Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Kevin K. Fuller
- Department of Microbiology & Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
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5
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Downes SG, Doyle S, Jones GW, Owens RA. Gliotoxin and related metabolites as zinc chelators: implications and exploitation to overcome antimicrobial resistance. Essays Biochem 2023; 67:769-780. [PMID: 36876884 PMCID: PMC10500201 DOI: 10.1042/ebc20220222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/03/2023] [Accepted: 02/06/2023] [Indexed: 03/07/2023]
Abstract
Antimicrobial resistance (AMR) is a major global problem and threat to humanity. The search for new antibiotics is directed towards targeting of novel microbial systems and enzymes, as well as augmenting the activity of pre-existing antimicrobials. Sulphur-containing metabolites (e.g., auranofin and bacterial dithiolopyrrolones [e.g., holomycin]) and Zn2+-chelating ionophores (PBT2) have emerged as important antimicrobial classes. The sulphur-containing, non-ribosomal peptide gliotoxin, biosynthesised by Aspergillus fumigatus and other fungi exhibits potent antimicrobial activity, especially in the dithiol form (dithiol gliotoxin; DTG). Specifically, it has been revealed that deletion of the enzymes gliotoxin oxidoreductase GliT, bis-thiomethyltransferase GtmA or the transporter GliA dramatically sensitise A. fumigatus to gliotoxin presence. Indeed, the double deletion strain A. fumigatus ΔgliTΔgtmA is especially sensitive to gliotoxin-mediated growth inhibition, which can be reversed by Zn2+ presence. Moreover, DTG is a Zn2+ chelator which can eject zinc from enzymes and inhibit activity. Although multiple studies have demonstrated the potent antibacterial effect of gliotoxin, no mechanistic details are available. Interestingly, reduced holomycin can inhibit metallo-β-lactamases. Since holomycin and gliotoxin can chelate Zn2+, resulting in metalloenzyme inhibition, we propose that this metal-chelating characteristic of these metabolites requires immediate investigation to identify new antibacterial drug targets or to augment the activity of existing antimicrobials. Given that (i) gliotoxin has been shown in vitro to significantly enhance vancomycin activity against Staphylococcus aureus, and (ii) that it has been independently proposed as an ideal probe to dissect the central 'Integrator' role of Zn2+ in bacteria - we contend such studies are immediately undertaken to help address AMR.
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Affiliation(s)
- Shane G Downes
- Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland
| | - Sean Doyle
- Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland
| | - Gary W Jones
- Centre for Biomedical Science Research, School of Health, Leeds Beckett University, Leeds LS1 3HE, U.K
| | - Rebecca A Owens
- Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland
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6
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Traynor AM, Sarikaya-Bayram Ö, Bayram Ö, Antonio Calera J, Doyle S. Proteomic dissection of the role of GliZ in gliotoxin biosynthesis in Aspergillus fumigatus. Fungal Genet Biol 2023; 166:103795. [PMID: 37023941 DOI: 10.1016/j.fgb.2023.103795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 03/30/2023] [Accepted: 03/31/2023] [Indexed: 04/08/2023]
Abstract
Gliotoxin (GT) biosynthesis in fungi is encoded by the gli biosynthetic gene cluster. While GT addition autoinduces biosynthesis, Zn2+ has been shown to attenuate cluster activity, and it was speculated that identification of Zn2Cys6 binuclear transcription factor GliZ binding partners might provide insight into this observation. Using the Tet-ON induction system, doxycycline (DOX) presence induced GliZ fusion protein expression in, and recovery of GT biosynthesis by, A. fumigatus ΔgliZ::HA-gliZ and ΔgliZ::TAP-gliZ strains, respectively. Quantitative RT-PCR confirmed that DOX induces gli cluster gene expression (n = 5) in both A. fumigatus HA-GliZ and TAP-GliZ strains. GT biosynthesis was evident in Czapek-Dox and in Sabouraud media, however tagged GliZ protein expression was more readily detected in Sabouraud media. Unexpectedly, Zn2+ was essential for GliZ fusion protein expression in vivo, following 3 h DOX induction. Moreover, HA-GliZ abundance was significantly higher in either DOX/GT or DOX/Zn2+, compared to DOX-only. This suggests that while GT induction is still intact, Zn2+ inhibition of HA-GliZ production in vivo is lost. Co-immunoprecipitation revealed that GT oxidoreductase GliT associates with GliZ in the presence of GT, suggesting a potential protective role. Additional putative HA-GliZ interacting proteins included cystathionine gamma lyase, ribosomal protein L15 and serine hydroxymethyltransferase (SHMT). Total mycelial quantitative proteomic data revealed that GliT and GtmA, as well as several other gli cluster proteins, are increased in abundance or uniquely expressed with GT addition. Proteins involved in sulphur metabolism are also differentially expressed with GT or Zn2+ presence. Overall, we disclose that under DOX induction GliZ functionality is unexpectedly evident in zinc-replete media, subject to GT induction and that GliT appears to associate with GliZ, potentially to prevent DTG-mediated GliZ inactivation by zinc ejection.
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Affiliation(s)
- Aimee M Traynor
- Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland
| | | | - Özgür Bayram
- Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland
| | - José Antonio Calera
- Instituto de Biología Funcional y Genómica (IBFG-CSIC), Universidad de Salamanca, Salamanca, Spain, Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain
| | - Sean Doyle
- Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland.
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7
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Okaa UJ, Bertuzzi M, Fortune-Grant R, Thomson DD, Moyes DL, Naglik JR, Bignell E. Aspergillus fumigatus Drives Tissue Damage via Iterative Assaults upon Mucosal Integrity and Immune Homeostasis. Infect Immun 2023; 91:e0033322. [PMID: 36625602 PMCID: PMC9933693 DOI: 10.1128/iai.00333-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 10/21/2022] [Indexed: 01/11/2023] Open
Abstract
The human lung is constantly exposed to Aspergillus fumigatus spores, the most prevalent worldwide cause of fungal respiratory disease. Pulmonary tissue damage is a unifying feature of Aspergillus-related diseases; however, the mechanistic basis of damage is not understood. In the lungs of susceptible hosts, A. fumigatus undergoes an obligatory morphological switch involving spore germination and hyphal growth. We modeled A. fumigatus infection in cultured A549 human pneumocytes, capturing the phosphoactivation status of five host signaling pathways, nuclear translocation and DNA binding of eight host transcription factors, and expression of nine host response proteins over six time points encompassing exposures to live fungus and the secretome thereof. The resulting data set, comprised of more than 1,000 data points, reveals that pneumocytes mount differential responses to A. fumigatus spores, hyphae, and soluble secreted products via the NF-κB, JNK, and JNK + p38 pathways, respectively. Importantly, via selective degradation of host proinflammatory (IL-6 and IL-8) cytokines and growth factors (FGF-2), fungal secreted products reorchestrate the host response to fungal challenge as well as driving multiparameter epithelial damage, culminating in cytolysis. Dysregulation of NF-κB signaling, involving sequential stimulation of canonical and noncanonical signaling, was identified as a significant feature of host damage both in vitro and in a mouse model of invasive aspergillosis. Our data demonstrate that composite tissue damage results from iterative (repeated) exposures to different fungal morphotypes and secreted products and suggest that modulation of host responses to fungal challenge might represent a unified strategy for therapeutic control of pathologically distinct types of Aspergillus-related disease.
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Affiliation(s)
- Uju Joy Okaa
- Centre for Host-Microbiome Interactions, Faculty of Dentistry, Oral & Craniofacial Sciences, King’s College London, London, United Kingdom
- Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Margherita Bertuzzi
- Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Rachael Fortune-Grant
- Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Darren D. Thomson
- Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
- MRC Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | - David L. Moyes
- Centre for Host-Microbiome Interactions, Faculty of Dentistry, Oral & Craniofacial Sciences, King’s College London, London, United Kingdom
| | - Julian R. Naglik
- Centre for Host-Microbiome Interactions, Faculty of Dentistry, Oral & Craniofacial Sciences, King’s College London, London, United Kingdom
| | - Elaine Bignell
- Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
- MRC Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
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8
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Huber EM. Epipolythiodioxopiperazine-Based Natural Products: Building Blocks, Biosynthesis and Biological Activities. Chembiochem 2022; 23:e202200341. [PMID: 35997236 PMCID: PMC10086836 DOI: 10.1002/cbic.202200341] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 08/19/2022] [Indexed: 01/25/2023]
Abstract
Epipolythiodioxopiperazines (ETPs) are fungal secondary metabolites that share a 2,5-diketopiperazine scaffold built from two amino acids and bridged by a sulfide moiety. Modifications of the core and the amino acid side chains, for example by methylations, acetylations, hydroxylations, prenylations, halogenations, cyclizations, and truncations create the structural diversity of ETPs and contribute to their biological activity. However, the key feature responsible for the bioactivities of ETPs is their sulfide moiety. Over the last years, combinations of genome mining, reverse genetics, metabolomics, biochemistry, and structural biology deciphered principles of ETP production. Sulfurization via glutathione and uncovering of the thiols followed by either oxidation or methylation crystallized as fundamental steps that impact expression of the biosynthesis cluster, toxicity and secretion of the metabolite as well as self-tolerance of the producer. This article showcases structure and activity of prototype ETPs such as gliotoxin and discusses the current knowledge on the biosynthesis routes of these exceptional natural products.
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Affiliation(s)
- Eva M Huber
- Chair of Biochemistry, Center for Protein Assemblies, Technical University of Munich, Ernst-Otto-Fischer-Str. 8, 85748, Garching, Germany
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9
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Martínez C, García-Domínguez P, Álvarez R, de Lera AR. Bispyrrolidinoindoline Epi(poly)thiodioxopiperazines (BPI-ETPs) and Simplified Mimetics: Structural Characterization, Bioactivities, and Total Synthesis. Molecules 2022; 27:7585. [PMID: 36364412 PMCID: PMC9659040 DOI: 10.3390/molecules27217585] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 10/25/2022] [Accepted: 10/26/2022] [Indexed: 09/08/2024] Open
Abstract
Within the 2,5-dioxopiperazine-containing natural products generated by "head-to-tail" cyclization of peptides, those derived from tryptophan allow further structural diversification due to the rich chemical reactivity of the indole heterocycle, which can generate tetracyclic fragments of hexahydropyrrolo[2,3-b]indole or pyrrolidinoindoline skeleton fused to the 2,5-dioxopiperazine. Even more complex are the dimeric bispyrrolidinoindoline epi(poly)thiodioxopiperazines (BPI-ETPs), since they feature transannular (poly)sulfide bridges connecting C3 and C6 of their 2,5-dioxopiperazine rings. Homo- and heterodimers composed of diastereomeric epi(poly)thiodioxopiperazines increase the complexity of the family. Furthermore, putative biogenetically generated downstream metabolites with C11 and C11'-hydroxylated cores, as well as deoxygenated and/or oxidized side chain counterparts, have also been described. The isolation of these complex polycyclic tryptophan-derived alkaloids from the classical sources, their structural characterization, the description of the relevant biological activities and putative biogenetic routes, and the synthetic efforts to generate and confirm their structures and also to prepare and further evaluate structurally simple analogs will be reported.
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Affiliation(s)
| | | | | | - Angel R. de Lera
- CINBIO, ORCHID Group, Departmento de Química Orgánica, Universidade de Vigo, 36310 Vigo, Spain
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10
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Xu R, Lou Y, Tidu A, Bulet P, Heinekamp T, Martin F, Brakhage A, Li Z, Liégeois S, Ferrandon D. The Toll pathway mediates Drosophila resilience to Aspergillus mycotoxins through specific Bomanins. EMBO Rep 2022; 24:e56036. [PMID: 36322050 PMCID: PMC9827548 DOI: 10.15252/embr.202256036] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 10/06/2022] [Accepted: 10/14/2022] [Indexed: 12/28/2022] Open
Abstract
Host defense against infections encompasses both resistance, which targets microorganisms for neutralization or elimination, and resilience/disease tolerance, which allows the host to withstand/tolerate pathogens and repair damages. In Drosophila, the Toll signaling pathway is thought to mediate resistance against fungal infections by regulating the secretion of antimicrobial peptides, potentially including Bomanins. We find that Aspergillus fumigatus kills Drosophila Toll pathway mutants without invasion because its dissemination is blocked by melanization, suggesting a role for Toll in host defense distinct from resistance. We report that mutants affecting the Toll pathway or the 55C Bomanin locus are susceptible to the injection of two Aspergillus mycotoxins, restrictocin and verruculogen. The vulnerability of 55C deletion mutants to these mycotoxins is rescued by the overexpression of Bomanins specific to each challenge. Mechanistically, flies in which BomS6 is expressed in the nervous system exhibit an enhanced recovery from the tremors induced by injected verruculogen and display improved survival. Thus, innate immunity also protects the host against the action of microbial toxins through secreted peptides and thereby increases its resilience to infection.
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Affiliation(s)
- Rui Xu
- Sino‐French Hoffmann InstituteGuangzhou Medical UniversityGuangzhouChina,Université de StrasbourgStrasbourgFrance,Modèles Insectes de l'Immunité InnéeUPR 9022 du CNRSStrasbourgFrance
| | - Yanyan Lou
- Sino‐French Hoffmann InstituteGuangzhou Medical UniversityGuangzhouChina,Université de StrasbourgStrasbourgFrance,Modèles Insectes de l'Immunité InnéeUPR 9022 du CNRSStrasbourgFrance
| | - Antonin Tidu
- Université de StrasbourgStrasbourgFrance,Architecture et Réactivité de l'ARNUPR 9002 du CNRSStrasbourgFrance
| | - Philippe Bulet
- CR Université Grenoble Alpes, Institute for Advanced Biosciences, Inserm U1209CNRS UMR 5309GrenobleFrance,Platform BioPark ArchampsArchampsFrance
| | - Thorsten Heinekamp
- Department of Molecular and Applied MicrobiologyLeibniz Institute for Natural Product Research and Infection Biology ‐ Hans Knöll Institute (Leibniz‐HKI)JenaGermany
| | - Franck Martin
- Université de StrasbourgStrasbourgFrance,Architecture et Réactivité de l'ARNUPR 9002 du CNRSStrasbourgFrance
| | - Axel Brakhage
- Department of Molecular and Applied MicrobiologyLeibniz Institute for Natural Product Research and Infection Biology ‐ Hans Knöll Institute (Leibniz‐HKI)JenaGermany,Institute of MicrobiologyFriedrich Schiller University JenaJenaGermany
| | - Zi Li
- Sino‐French Hoffmann InstituteGuangzhou Medical UniversityGuangzhouChina
| | - Samuel Liégeois
- Sino‐French Hoffmann InstituteGuangzhou Medical UniversityGuangzhouChina,Université de StrasbourgStrasbourgFrance,Modèles Insectes de l'Immunité InnéeUPR 9022 du CNRSStrasbourgFrance
| | - Dominique Ferrandon
- Sino‐French Hoffmann InstituteGuangzhou Medical UniversityGuangzhouChina,Université de StrasbourgStrasbourgFrance,Modèles Insectes de l'Immunité InnéeUPR 9022 du CNRSStrasbourgFrance
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11
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Lofgren LA, Ross BS, Cramer RA, Stajich JE. The pan-genome of Aspergillus fumigatus provides a high-resolution view of its population structure revealing high levels of lineage-specific diversity driven by recombination. PLoS Biol 2022; 20:e3001890. [PMID: 36395320 PMCID: PMC9714929 DOI: 10.1371/journal.pbio.3001890] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 12/01/2022] [Accepted: 10/26/2022] [Indexed: 11/18/2022] Open
Abstract
Aspergillus fumigatus is a deadly agent of human fungal disease where virulence heterogeneity is thought to be at least partially structured by genetic variation between strains. While population genomic analyses based on reference genome alignments offer valuable insights into how gene variants are distributed across populations, these approaches fail to capture intraspecific variation in genes absent from the reference genome. Pan-genomic analyses based on de novo assemblies offer a promising alternative to reference-based genomics with the potential to address the full genetic repertoire of a species. Here, we evaluate 260 genome sequences of A. fumigatus including 62 newly sequenced strains, using a combination of population genomics, phylogenomics, and pan-genomics. Our results offer a high-resolution assessment of population structure and recombination frequency, phylogenetically structured gene presence-absence variation, evidence for metabolic specificity, and the distribution of putative antifungal resistance genes. Although A. fumigatus disperses primarily via asexual conidia, we identified extraordinarily high levels of recombination with the lowest linkage disequilibrium decay value reported for any fungal species to date. We provide evidence for 3 primary populations of A. fumigatus, with recombination occurring only rarely between populations and often within them. These 3 populations are structured by both gene variation and distinct patterns of gene presence-absence with unique suites of accessory genes present exclusively in each clade. Accessory genes displayed functional enrichment for nitrogen and carbohydrate metabolism suggesting that populations may be stratified by environmental niche specialization. Similarly, the distribution of antifungal resistance genes and resistance alleles were often structured by phylogeny. Altogether, the pan-genome of A. fumigatus represents one of the largest fungal pan-genomes reported to date including many genes unrepresented in the Af293 reference genome. These results highlight the inadequacy of relying on a single-reference genome-based approach for evaluating intraspecific variation and the power of combined genomic approaches to elucidate population structure, genetic diversity, and putative ecological drivers of clinically relevant fungi.
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Affiliation(s)
- Lotus A. Lofgren
- Department of Microbiology and Plant Pathology, University of California Riverside, Riverside, California, United States of America
- Department of Biology, Duke University, Durham, North Carolina, United States of America
| | - Brandon S. Ross
- Dartmouth Geisel School of Medicine in the Department of Microbiology and Immunology, Dartmouth, Hanover, New Hampshire, United States of America
| | - Robert A. Cramer
- Dartmouth Geisel School of Medicine in the Department of Microbiology and Immunology, Dartmouth, Hanover, New Hampshire, United States of America
| | - Jason E. Stajich
- Department of Microbiology and Plant Pathology, University of California Riverside, Riverside, California, United States of America
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12
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Redrado S, Esteban P, Domingo MP, Lopez C, Rezusta A, Ramirez-Labrada A, Arias M, Pardo J, Galvez EM. Integration of In Silico and In Vitro Analysis of Gliotoxin Production Reveals a Narrow Range of Producing Fungal Species. J Fungi (Basel) 2022; 8:jof8040361. [PMID: 35448592 PMCID: PMC9030297 DOI: 10.3390/jof8040361] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 03/28/2022] [Accepted: 03/29/2022] [Indexed: 02/06/2023] Open
Abstract
Gliotoxin is a fungal secondary metabolite with impact on health and agriculture since it might act as virulence factor and contaminate human and animal food. Homologous gliotoxin (GT) gene clusters are spread across a number of fungal species although if they produce GT or other related epipolythiodioxopiperazines (ETPs) remains obscure. Using bioinformatic tools, we have identified homologous gli gene clusters similar to the A. fumigatus GT gene cluster in several fungal species. In silico study led to in vitro confirmation of GT and Bisdethiobis(methylthio)gliotoxin (bmGT) production in fungal strain cultures by HPLC detection. Despite we selected most similar homologous gli gene cluster in 20 different species, GT and bmGT were only detected in section Fumigati species and in a Trichoderma virens Q strain. Our results suggest that in silico gli homology analyses in different fungal strains to predict GT production might be only informative when accompanied by analysis about mycotoxin production in cell cultures.
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Affiliation(s)
- Sergio Redrado
- Instituto de Carboquımica ICB-CSIC, 50018 Zaragoza, Spain; (S.R.); (M.P.D.)
| | - Patricia Esteban
- Biomedical Research Centre of Aragon (CIBA), Fundacion Instituto de Investigacion Sanitaria Aragon (IIS Aragon), 50009 Zaragoza, Spain; (P.E.); (A.R.-L.); (M.A.); (J.P.)
| | | | - Concepción Lopez
- Department of Microbiology, Hospital Universitario Miguel Servet, IIS Aragón, 50009 Zaragoza, Spain; (C.L.); (A.R.)
| | - Antonio Rezusta
- Department of Microbiology, Hospital Universitario Miguel Servet, IIS Aragón, 50009 Zaragoza, Spain; (C.L.); (A.R.)
| | - Ariel Ramirez-Labrada
- Biomedical Research Centre of Aragon (CIBA), Fundacion Instituto de Investigacion Sanitaria Aragon (IIS Aragon), 50009 Zaragoza, Spain; (P.E.); (A.R.-L.); (M.A.); (J.P.)
| | - Maykel Arias
- Biomedical Research Centre of Aragon (CIBA), Fundacion Instituto de Investigacion Sanitaria Aragon (IIS Aragon), 50009 Zaragoza, Spain; (P.E.); (A.R.-L.); (M.A.); (J.P.)
| | - Julián Pardo
- Biomedical Research Centre of Aragon (CIBA), Fundacion Instituto de Investigacion Sanitaria Aragon (IIS Aragon), 50009 Zaragoza, Spain; (P.E.); (A.R.-L.); (M.A.); (J.P.)
- Department of Microbiology, Pediatrics, Radiology and Public Health, University of Zaragoza, 50009 Zaragoza, Spain
- Aragon I+D Foundation (ARAID), 50018 Zaragoza, Spain
| | - Eva M. Galvez
- Instituto de Carboquımica ICB-CSIC, 50018 Zaragoza, Spain; (S.R.); (M.P.D.)
- Correspondence:
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13
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Margalit A, Sheehan D, Carolan JC, Kavanagh K. Exposure to the Pseudomonas aeruginosa secretome alters the proteome and secondary metabolite production of Aspergillus fumigatus. MICROBIOLOGY (READING, ENGLAND) 2022; 168:001164. [PMID: 35333152 PMCID: PMC9558348 DOI: 10.1099/mic.0.001164] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 02/16/2022] [Indexed: 01/09/2023]
Abstract
The fungal pathogen Aspergillus fumigatus is frequently cultured from the sputum of cystic fibrosis (CF) patients along with the bacterium Pseudomonas aeruginosa. A. fumigatus secretes a range of secondary metabolites, and one of these, gliotoxin, has inhibitory effects on the host immune response. The effect of P. aeruginosa culture filtrate (CuF) on fungal growth and gliotoxin production was investigated. Exposure of A. fumigatus hyphae to P. aeruginosa cells induced increased production of gliotoxin and a decrease in fungal growth. In contrast, exposure of A. fumigatus hyphae to P. aeruginosa CuF led to increased growth and decreased gliotoxin production. Quantitative proteomic analysis was used to characterize the proteomic response of A. fumigatus upon exposure to P. aeruginosa CuF. Changes in the profile of proteins involved in secondary metabolite biosynthesis (e.g. gliotoxin, fumagillin, pseurotin A), and changes to the abundance of proteins involved in oxidative stress (e.g. formate dehydrogenase) and detoxification (e.g. thioredoxin reductase) were observed, indicating that the bacterial secretome had a profound effect on the fungal proteome. Alterations in the abundance of proteins involved in detoxification and oxidative stress highlight the ability of A. fumigatus to differentially regulate protein synthesis in response to environmental stresses imposed by competitors such as P. aeruginosa. Such responses may ultimately have serious detrimental effects on the host.
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Affiliation(s)
- Anatte Margalit
- Department of Biology, Maynooth University, Co. Kildare, Ireland
| | - David Sheehan
- Department of Biology, Maynooth University, Co. Kildare, Ireland
| | - James C. Carolan
- Department of Biology, Maynooth University, Co. Kildare, Ireland
| | - Kevin Kavanagh
- Department of Biology, Maynooth University, Co. Kildare, Ireland
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14
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de Castro PA, Colabardini AC, Moraes M, Horta MAC, Knowles SL, Raja HA, Oberlies NH, Koyama Y, Ogawa M, Gomi K, Steenwyk JL, Rokas A, Gonçales RA, Duarte-Oliveira C, Carvalho A, Ries LNA, Goldman GH. Regulation of gliotoxin biosynthesis and protection in Aspergillus species. PLoS Genet 2022; 18:e1009965. [PMID: 35041649 PMCID: PMC8797188 DOI: 10.1371/journal.pgen.1009965] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/28/2022] [Accepted: 01/04/2022] [Indexed: 02/07/2023] Open
Abstract
Aspergillus fumigatus causes a range of human and animal diseases collectively known as aspergillosis. A. fumigatus possesses and expresses a range of genetic determinants of virulence, which facilitate colonisation and disease progression, including the secretion of mycotoxins. Gliotoxin (GT) is the best studied A. fumigatus mycotoxin with a wide range of known toxic effects that impair human immune cell function. GT is also highly toxic to A. fumigatus and this fungus has evolved self-protection mechanisms that include (i) the GT efflux pump GliA, (ii) the GT neutralising enzyme GliT, and (iii) the negative regulation of GT biosynthesis by the bis-thiomethyltransferase GtmA. The transcription factor (TF) RglT is the main regulator of GliT and this GT protection mechanism also occurs in the non-GT producing fungus A. nidulans. However, the A. nidulans genome does not encode GtmA and GliA. This work aimed at analysing the transcriptional response to exogenous GT in A. fumigatus and A. nidulans, two distantly related Aspergillus species, and to identify additional components required for GT protection. RNA-sequencing shows a highly different transcriptional response to exogenous GT with the RglT-dependent regulon also significantly differing between A. fumigatus and A. nidulans. However, we were able to observe homologs whose expression pattern was similar in both species (43 RglT-independent and 11 RglT-dependent). Based on this approach, we identified a novel RglT-dependent methyltranferase, MtrA, involved in GT protection. Taking into consideration the occurrence of RglT-independent modulated genes, we screened an A. fumigatus deletion library of 484 transcription factors (TFs) for sensitivity to GT and identified 15 TFs important for GT self-protection. Of these, the TF KojR, which is essential for kojic acid biosynthesis in Aspergillus oryzae, was also essential for virulence and GT biosynthesis in A. fumigatus, and for GT protection in A. fumigatus, A. nidulans, and A. oryzae. KojR regulates rglT, gliT, gliJ expression and sulfur metabolism in Aspergillus species. Together, this study identified conserved components required for GT protection in Aspergillus species. A. fumigatus secretes mycotoxins that are essential for its virulence and pathogenicity. Gliotoxin (GT) is a sulfur-containing mycotoxin, which is known to impair several aspects of the human immune response. GT is also toxic to different fungal species, which have evolved several GT protection strategies. To further decipher these responses, we used transcriptional profiling aiming to compare the response to GT in the GT producer A. fumigatus and the GT non-producer A. nidulans. This analysis allowed us to identify additional genes with a potential role in GT protection. We also identified 15 transcription factors (TFs) encoded in the A. fumigatus genome that are important for conferring resistance to exogenous gliotoxin. One of these TFs, KojR, which is essential for A. oryzae kojic acid production, is also important for virulence in A. fumigatus and GT protection in A. fumigatus, A. nidulans and A. oryzae. KojR regulates the expression of genes important for gliotoxin biosynthesis and protection, and sulfur metabolism. Together, this work identified conserved components required for gliotoxin protection in Aspergillus species.
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Affiliation(s)
- Patrícia Alves de Castro
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Ana Cristina Colabardini
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Maísa Moraes
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | | | - Sonja L. Knowles
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, North Carolina United States of America
| | - Huzefa A. Raja
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, North Carolina United States of America
| | - Nicholas H. Oberlies
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, North Carolina United States of America
| | - Yasuji Koyama
- Noda Institute for Scientific Research, 338 Noda, Chiba, Japan
| | - Masahiro Ogawa
- Noda Institute for Scientific Research, 338 Noda, Chiba, Japan
| | - Katsuya Gomi
- Department of Bioindustrial Informatics and Genomics, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Jacob L. Steenwyk
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Antonis Rokas
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Relber A. Gonçales
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B’s—PT Government Associate Laboratory, Guimarães/Braga, Portugal
| | - Cláudio Duarte-Oliveira
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B’s—PT Government Associate Laboratory, Guimarães/Braga, Portugal
| | - Agostinho Carvalho
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B’s—PT Government Associate Laboratory, Guimarães/Braga, Portugal
| | - Laure N. A. Ries
- MRC Centre for Medical Mycology at the University of Exeter, Geoffrey Pope Building, Exeter, United Kingdom
- * E-mail: (LNAR); (GHG)
| | - Gustavo H. Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
- * E-mail: (LNAR); (GHG)
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15
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Hai Y, Wei MY, Wang CY, Gu YC, Shao CL. The intriguing chemistry and biology of sulfur-containing natural products from marine microorganisms (1987-2020). MARINE LIFE SCIENCE & TECHNOLOGY 2021; 3:488-518. [PMID: 37073258 PMCID: PMC10077240 DOI: 10.1007/s42995-021-00101-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Accepted: 03/18/2021] [Indexed: 05/03/2023]
Abstract
Natural products derived from marine microorganisms have received great attention as a potential resource of new compound entities for drug discovery. The unique marine environment brings us a large group of sulfur-containing natural products with abundant biological functionality including antitumor, antibiotic, anti-inflammatory and antiviral activities. We reviewed all the 484 sulfur-containing natural products (non-sulfated) isolated from marine microorganisms, of which 59.9% are thioethers, 29.8% are thiazole/thiazoline-containing compounds and 10.3% are sulfoxides, sulfones, thioesters and many others. A selection of 133 compounds was further discussed on their structure-activity relationships, mechanisms of action, biosynthesis, and druggability. This is the first systematic review on sulfur-containing natural products from marine microorganisms conducted from January 1987, when the first one was reported, to December 2020. Supplementary Information The online version contains supplementary material available at 10.1007/s42995-021-00101-2.
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Affiliation(s)
- Yang Hai
- Key Laboratory of Marine Drugs, School of Medicine and Pharmacy, The Ministry of Education of China, Ocean University of China, Qingdao, 266003 China
- Laboratory for Marine Drugs and Bioproducts, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266237 China
| | - Mei-Yan Wei
- Key Laboratory of Marine Drugs, School of Medicine and Pharmacy, The Ministry of Education of China, Ocean University of China, Qingdao, 266003 China
- College of Food Science and Engineering, Ocean University of China, Qingdao, 266003 China
| | - Chang-Yun Wang
- Key Laboratory of Marine Drugs, School of Medicine and Pharmacy, The Ministry of Education of China, Ocean University of China, Qingdao, 266003 China
- Laboratory for Marine Drugs and Bioproducts, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266237 China
| | - Yu-Cheng Gu
- Syngenta Jealott’s Hill International Research Centre, Bracknell, Berkshire RG42 6EY UK
| | - Chang-Lun Shao
- Key Laboratory of Marine Drugs, School of Medicine and Pharmacy, The Ministry of Education of China, Ocean University of China, Qingdao, 266003 China
- Laboratory for Marine Drugs and Bioproducts, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266237 China
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16
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Identification of Novel Mutations Contributing to Azole Tolerance of Aspergillus fumigatus through In Vitro Exposure to Tebuconazole. Antimicrob Agents Chemother 2021; 65:e0265720. [PMID: 34125587 DOI: 10.1128/aac.02657-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Azole resistance of Aspergillus fumigatus is a global problem. The major resistance mechanism is through cytochrome P450 14-α sterol demethylase Cyp51A alterations such as a mutation(s) in the gene and the acquisition of a tandem repeat in the promoter. Although other azole tolerance and resistance mechanisms, such as the hmg1 (a 3-hydroxy-3-methylglutaryl coenzyme-A reductase gene) mutation, are known, few reports have described studies elucidating non-Cyp51A resistance mechanisms. This study explored genes contributing to azole tolerance in A. fumigatus by in vitro mutant selection with tebuconazole, an azole fungicide. After three rounds of selection, we obtained four isolates with low susceptibility to tebuconazole. These isolates also showed low susceptibility to itraconazole and voriconazole. Comparison of the genome sequences of the isolates obtained and the parental strain revealed a nonsynonymous mutation in MfsD, a major facilitator superfamily protein (Afu1g11820; R337L mutation [a change of R to L at position 337]), in all isolates. Furthermore, nonsynonymous mutations in AgcA, a mitochondrial inner membrane aspartate/glutamate transporter (Afu7g05220; E535Stop mutation), UbcD, a ubiquitin-conjugating enzyme E2 (Afu3g06030; T98K mutation), AbcJ, an ABC transporter (Afu3g12220; G297E mutation), and RttA, a putative protein responsible for tebuconazole tolerance (Afu7g04740; A83T mutation), were found in at least one isolate. Disruption of the agcA gene led to decreased susceptibility to azoles. Reconstruction of the A83T point mutation in RttA led to decreased susceptibility to azoles. Reversion of the T98K mutation in UbcD to the wild type led to decreased susceptibility to azoles. These results suggest that these mutations contribute to lowered susceptibility to medical azoles and agricultural azole fungicides.
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17
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Boysen JM, Saeed N, Hillmann F. Natural products in the predatory defence of the filamentous fungal pathogen Aspergillus fumigatus. Beilstein J Org Chem 2021; 17:1814-1827. [PMID: 34394757 PMCID: PMC8336654 DOI: 10.3762/bjoc.17.124] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 07/14/2021] [Indexed: 11/30/2022] Open
Abstract
The kingdom of fungi comprises a large and highly diverse group of organisms that thrive in diverse natural environments. One factor to successfully confront challenges in their natural habitats is the capability to synthesize defensive secondary metabolites. The genetic potential for the production of secondary metabolites in fungi is high and numerous potential secondary metabolite gene clusters have been identified in sequenced fungal genomes. Their production may well be regulated by specific ecological conditions, such as the presence of microbial competitors, symbionts or predators. Here we exemplarily summarize our current knowledge on identified secondary metabolites of the pathogenic fungus Aspergillus fumigatus and their defensive function against (microbial) predators.
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Affiliation(s)
- Jana M Boysen
- Junior Research Group Evolution of Microbial Interactions, Leibniz-Institute for Natural Product Research and Infection Biology – Hans Knöll Institute (HKI), Beutenbergstr. 11a, 07745 Jena, Germany
- Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany
| | - Nauman Saeed
- Junior Research Group Evolution of Microbial Interactions, Leibniz-Institute for Natural Product Research and Infection Biology – Hans Knöll Institute (HKI), Beutenbergstr. 11a, 07745 Jena, Germany
- Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany
| | - Falk Hillmann
- Junior Research Group Evolution of Microbial Interactions, Leibniz-Institute for Natural Product Research and Infection Biology – Hans Knöll Institute (HKI), Beutenbergstr. 11a, 07745 Jena, Germany
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18
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Scherlach K, Kuttenlochner W, Scharf DH, Brakhage AA, Hertweck C, Groll M, Huber EM. Strukturelle und mechanistische Einblicke in die Bildung der C‐S‐Bindungen in Gliotoxin. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202104372] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Kirstin Scherlach
- Abteilung Biomolekulare Chemie Leibniz-Institut für Naturstoff-Forschung und Infektionsbiologie (HKI) Beutenbergstraße 11a 07745 Jena Deutschland
| | - Wolfgang Kuttenlochner
- Technische Universität München Zentrum für Proteinforschung (CPA) Ernst-Otto-Fischer-Straße 8 85747 Garching Deutschland
| | - Daniel H. Scharf
- Abteilung Molekulare und Angewandte Mikrobiologie Leibniz-Institut für Naturstoff-Forschung und Infektionsbiologie (HKI) Beutenbergstraße 11a 07745 Jena Deutschland
- Abteilung Mikrobiologie und Kinderkrankenhaus Zhejiang Universität Fakultät für Medizin Hangzhou 310058 Zhejiang V.R. China
| | - Axel A. Brakhage
- Abteilung Molekulare und Angewandte Mikrobiologie Leibniz-Institut für Naturstoff-Forschung und Infektionsbiologie (HKI) Beutenbergstraße 11a 07745 Jena Deutschland
- Fakultät für Biowissenschaften Friedrich Schiller Universität Jena 07743 Jena Deutschland
| | - Christian Hertweck
- Abteilung Biomolekulare Chemie Leibniz-Institut für Naturstoff-Forschung und Infektionsbiologie (HKI) Beutenbergstraße 11a 07745 Jena Deutschland
- Fakultät für Biowissenschaften Friedrich Schiller Universität Jena 07743 Jena Deutschland
| | - Michael Groll
- Technische Universität München Zentrum für Proteinforschung (CPA) Ernst-Otto-Fischer-Straße 8 85747 Garching Deutschland
| | - Eva M. Huber
- Technische Universität München Zentrum für Proteinforschung (CPA) Ernst-Otto-Fischer-Straße 8 85747 Garching Deutschland
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19
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Scherlach K, Kuttenlochner W, Scharf DH, Brakhage AA, Hertweck C, Groll M, Huber EM. Structural and Mechanistic Insights into C-S Bond Formation in Gliotoxin. Angew Chem Int Ed Engl 2021; 60:14188-14194. [PMID: 33909314 PMCID: PMC8251611 DOI: 10.1002/anie.202104372] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Indexed: 12/01/2022]
Abstract
Glutathione‐S‐transferases (GSTs) usually detoxify xenobiotics. The human pathogenic fungus Aspergillus fumigatus however uses the exceptional GST GliG to incorporate two sulfur atoms into its virulence factor gliotoxin. Because these sulfurs are essential for biological activity, glutathionylation is a key step of gliotoxin biosynthesis. Yet, the mechanism of carbon−sulfur linkage formation from a bis‐hydroxylated precursor is unresolved. Here, we report structures of GliG with glutathione (GSH) and its reaction product cyclo[‐l‐Phe‐l‐Ser]‐bis‐glutathione, which has been purified from a genetically modified A. fumigatus strain. The structures argue for stepwise processing of first the Phe and second the Ser moiety. Enzyme‐mediated dehydration of the substrate activates GSH and a helix dipole stabilizes the resulting anion via a water molecule for the nucleophilic attack. Activity assays with mutants validate the interactions of GliG with the ligands and enrich our knowledge about enzymatic C−S bond formation in gliotoxin and epipolythiodioxopiperazine (ETP) natural compounds in general.
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Affiliation(s)
- Kirstin Scherlach
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstrasse 11a, 07745, Jena, Germany
| | - Wolfgang Kuttenlochner
- Technical University of Munich, Center for Protein Assemblies, Ernst-Otto-Fischer-Strasse 8, 85747, Garching, Germany
| | - Daniel H Scharf
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstrasse 11a, 07745, Jena, Germany.,Department of Microbiology and The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, Zhejiang, P.R. China
| | - Axel A Brakhage
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstrasse 11a, 07745, Jena, Germany.,Faculty of Biological Sciences, Friedrich Schiller University Jena, 07743, Jena, Germany
| | - Christian Hertweck
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstrasse 11a, 07745, Jena, Germany.,Faculty of Biological Sciences, Friedrich Schiller University Jena, 07743, Jena, Germany
| | - Michael Groll
- Technical University of Munich, Center for Protein Assemblies, Ernst-Otto-Fischer-Strasse 8, 85747, Garching, Germany
| | - Eva M Huber
- Technical University of Munich, Center for Protein Assemblies, Ernst-Otto-Fischer-Strasse 8, 85747, Garching, Germany
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20
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Adrover-Castellano ML, Schmidt JJ, Sherman DH. Biosynthetic Cyclization Catalysts for the Assembly of Peptide and Polyketide Natural Products. ChemCatChem 2021; 13:2095-2116. [PMID: 34335987 PMCID: PMC8320681 DOI: 10.1002/cctc.202001886] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Indexed: 12/13/2022]
Abstract
Many biologically active natural products are synthesized by nonribosomal peptide synthetases (NRPSs), polyketide synthases (PKSs) and their hybrids. These megasynthetases contain modules possessing distinct catalytic domains that allow for substrate initiation, chain extension, processing and termination. At the end of a module, a terminal domain, usually a thioesterase (TE), is responsible for catalyzing the release of the NRPS or PKS as a linear or cyclized product. In this review, we address the general cyclization mechanism of the TE domain, including oligomerization and the fungal C-C bond forming Claisen-like cyclases (CLCs). Additionally, we include examples of cyclization catalysts acting within or at the end of a module. Furthermore, condensation-like (CT) domains, terminal reductase (R) domains, reductase-like domains that catalyze Dieckmann condensation (RD), thioesterase-like Dieckmann cyclases, trans-acting TEs from the penicillin binding protein (PBP) enzyme family, product template (PT) domains and others will also be reviewed. The studies summarized here highlight the remarkable diversity of NRPS and PKS cyclization catalysts for the production of biologically relevant, complex cyclic natural products and related compounds.
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Affiliation(s)
| | - Jennifer J Schmidt
- Life Sciences Institute, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, MI 48109-2216 (USA)
| | - David H Sherman
- Life Sciences Institute, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, MI 48109-2216 (USA)
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21
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The Peroxiredoxin Asp f3 Acts as Redox Sensor in Aspergillus fumigatus. Genes (Basel) 2021; 12:genes12050668. [PMID: 33946853 PMCID: PMC8145481 DOI: 10.3390/genes12050668] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/24/2021] [Accepted: 04/27/2021] [Indexed: 11/16/2022] Open
Abstract
The human pathogenic fungus Aspergillus fumigatus is readily eradicated by the innate immunity of immunocompetent human hosts, but can cause severe infections, such as invasive aspergillosis (IA), in immunocompromised individuals. During infection, the fungal redox homeostasis can be challenged by reactive oxygen species (ROS), either derived from the oxidative burst of innate immune cells or the action of antifungal drugs. The peroxiredoxin Asp f3 was found to be essential to cause IA in mice, but how Asp f3 integrates with fungal redox homeostasis remains unknown. Here, we show that in vivo, Asp f3 acts as a sensor for ROS. While global transcription in fungal hyphae under minimal growth conditions was fully independent of Asp f3, a robust induction of the oxidative stress response required the presence of the peroxiredoxin. Hyphae devoid of Asp f3 failed to activate several redox active genes, like members of the gliotoxin biosynthesis gene cluster and integral members of the Afyap1 regulon, the central activator of the ROS defense machinery in fungi. Upon deletion of the asp f3 gene Afyap1 displayed significantly reduced nuclear localization during ROS exposure, indicating that Asp f3 can act as an intracellular redox sensor for several target proteins.
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22
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Understanding the fundamental role of virulence determinants to combat Aspergillus fumigatus infections: exploring beyond cell wall. Mycol Prog 2021. [DOI: 10.1007/s11557-021-01677-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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23
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Takahashi H, Umemura M, Ninomiya A, Kusuya Y, Shimizu M, Urayama SI, Watanabe A, Kamei K, Yaguchi T, Hagiwara D. Interspecies Genomic Variation and Transcriptional Activeness of Secondary Metabolism-Related Genes in Aspergillus Section Fumigati. FRONTIERS IN FUNGAL BIOLOGY 2021; 2:656751. [PMID: 37744138 PMCID: PMC10512231 DOI: 10.3389/ffunb.2021.656751] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 03/23/2021] [Indexed: 09/26/2023]
Abstract
Filamentous fungi produce various bioactive compounds that are biosynthesized by sets of proteins encoded in biosynthesis gene clusters (BGCs). For an unknown reason, many BGCs are transcriptionally silent in laboratory conditions, which has hampered the discovery of novel fungal compounds. The transcriptional reactiveness of fungal secondary metabolism is not fully understood. To gain the comprehensive view, we conducted comparative genomic and transcriptomic analyses of nine closely-related species of Aspergillus section Fumigati (A. fumigatus, A. fumigatiaffinis, A. novofumigatus, A. thermomutatus, A. viridinutans, A. pseudoviridinutans, A. lentulus, A. udagawae, and Neosartorya fischeri). For expanding our knowledge, we newly sequenced genomes of A. viridinutans and A. pseudoviridinutans, and reassembled and reannotated the previously released genomes of A. lentulus and A. udagawae. Between 34 and 84 secondary metabolite (SM) backbone genes were identified in the genomes of these nine respective species, with 8.7-51.2% being unique to the species. A total of 247 SM backbone gene types were identified in the nine fungi. Ten BGCs are shared by all nine species. Transcriptomic analysis using A. fumigatus, A. lentulus, A. udagawae, A. viridinutans, and N. fischeri was conducted to compare expression levels of all SM backbone genes in four different culture conditions; 32-83% of SM backbone genes in these species were not expressed in the tested conditions, which reconfirmed that large part of fungal SM genes are hard to be expressed. The species-unique SM genes of the five species were expressed with lower frequency (18.8% in total) than the SM genes that are conserved in all five species (56%). These results suggest that the expression tendency of BGCs is correlated with their interspecies distribution pattern. Our findings increase understanding of the evolutionary processes associated with the regulation of fungal secondary metabolism.
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Affiliation(s)
- Hiroki Takahashi
- Medical Mycology Research Center, Chiba University, Chiba, Japan
- Molecular Chirality Research Center, Chiba University, Chiba, Japan
- Plant Molecular Science Center, Chiba University, Chiba, Japan
| | - Maiko Umemura
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | - Akihiro Ninomiya
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Yoko Kusuya
- Medical Mycology Research Center, Chiba University, Chiba, Japan
| | - Masaaki Shimizu
- Department of Biology, Faculty of Science, Chiba University, Chiba, Japan
| | - Syun-ichi Urayama
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
- Microbiology Research Center for Sustainability, University of Tsukuba, Tsukuba, Japan
| | - Akira Watanabe
- Medical Mycology Research Center, Chiba University, Chiba, Japan
| | - Katsuhiko Kamei
- Medical Mycology Research Center, Chiba University, Chiba, Japan
| | - Takashi Yaguchi
- Medical Mycology Research Center, Chiba University, Chiba, Japan
| | - Daisuke Hagiwara
- Medical Mycology Research Center, Chiba University, Chiba, Japan
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
- Microbiology Research Center for Sustainability, University of Tsukuba, Tsukuba, Japan
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24
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Alam B, Lǐ J, Gě Q, Khan MA, Gōng J, Mehmood S, Yuán Y, Gǒng W. Endophytic Fungi: From Symbiosis to Secondary Metabolite Communications or Vice Versa? FRONTIERS IN PLANT SCIENCE 2021; 12:791033. [PMID: 34975976 PMCID: PMC8718612 DOI: 10.3389/fpls.2021.791033] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 11/29/2021] [Indexed: 05/08/2023]
Abstract
Endophytic fungi (EF) are a group of fascinating host-associated fungal communities that colonize the intercellular or intracellular spaces of host tissues, providing beneficial effects to their hosts while gaining advantages. In recent decades, accumulated research on endophytic fungi has revealed their biodiversity, wide-ranging ecological distribution, and multidimensional interactions with host plants and other microbiomes in the symbiotic continuum. In this review, we highlight the role of secondary metabolites (SMs) as effectors in these multidimensional interactions, and the biosynthesis of SMs in symbiosis via complex gene expression regulation mechanisms in the symbiotic continuum and via the mimicry or alteration of phytochemical production in host plants. Alternative biological applications of SMs in modern medicine, agriculture, and industry and their major classes are also discussed. This review recapitulates an introduction to the research background, progress, and prospects of endophytic biology, and discusses problems and substantive challenges that need further study.
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Affiliation(s)
- Beena Alam
- State Key Laboratory of Cotton Biology, Key Laboratory of Biological and Genetic Breeding of Cotton, The Ministry of Agriculture, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
| | - Jùnwén Lǐ
- State Key Laboratory of Cotton Biology, Key Laboratory of Biological and Genetic Breeding of Cotton, The Ministry of Agriculture, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
| | - Qún Gě
- State Key Laboratory of Cotton Biology, Key Laboratory of Biological and Genetic Breeding of Cotton, The Ministry of Agriculture, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
| | - Mueen Alam Khan
- Department of Plant Breeding & Genetics, University College of Agriculture and Environmental Sciences, The Islamia University of Bahawalpur (IUB), Bahawalpur, Pakistan
| | - Jǔwǔ Gōng
- State Key Laboratory of Cotton Biology, Key Laboratory of Biological and Genetic Breeding of Cotton, The Ministry of Agriculture, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
| | - Shahid Mehmood
- Biotechnology Research Institute (BRI), Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yǒulù Yuán
- State Key Laboratory of Cotton Biology, Key Laboratory of Biological and Genetic Breeding of Cotton, The Ministry of Agriculture, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
- *Correspondence: Wànkuí Gǒng,
| | - Wànkuí Gǒng
- State Key Laboratory of Cotton Biology, Key Laboratory of Biological and Genetic Breeding of Cotton, The Ministry of Agriculture, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
- Yǒulù Yuán,
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25
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Tamez-Castrellón AK, Romeo O, García-Carnero LC, Lozoya-Pérez NE, Mora-Montes HM. Virulence Factors in Sporothrix schenckii, One of the Causative Agents of Sporotrichosis. Curr Protein Pept Sci 2021; 21:295-312. [PMID: 31589121 DOI: 10.2174/1389203720666191007103004] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 08/02/2019] [Accepted: 08/08/2019] [Indexed: 11/22/2022]
Abstract
Sporothrix schenckii is one of the etiological agents of sporotrichosis, a fungal infection distributed worldwide. Both, the causative organism and the disease have currently received limited attention by the medical mycology community, most likely because of the low mortality rates associated with it. Nonetheless, morbidity is high in endemic regions and the versatility of S. schenckii to cause zoonosis and sapronosis has attracted attention. Thus far, virulence factors associated with this organism are poorly described. Here, comparing the S. schenckii genome sequence with other medically relevant fungi, genes involved in morphological change, cell wall synthesis, immune evasion, thermotolerance, adhesion, biofilm formation, melanin production, nutrient uptake, response to stress, extracellular vesicle formation, and toxin production are predicted and discussed as putative virulence factors in S. schenckii.
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Affiliation(s)
- Alma K Tamez-Castrellón
- Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Noria Alta s/n, col. Noria Alta, C.P. 36050, Guanajuato, Gto., Mexico
| | - Orazio Romeo
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
| | - Laura C García-Carnero
- Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Noria Alta s/n, col. Noria Alta, C.P. 36050, Guanajuato, Gto., Mexico
| | - Nancy E Lozoya-Pérez
- Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Noria Alta s/n, col. Noria Alta, C.P. 36050, Guanajuato, Gto., Mexico
| | - Héctor M Mora-Montes
- Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Noria Alta s/n, col. Noria Alta, C.P. 36050, Guanajuato, Gto., Mexico
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El Hajj Assaf C, Zetina-Serrano C, Tahtah N, Khoury AE, Atoui A, Oswald IP, Puel O, Lorber S. Regulation of Secondary Metabolism in the Penicillium Genus. Int J Mol Sci 2020; 21:E9462. [PMID: 33322713 PMCID: PMC7763326 DOI: 10.3390/ijms21249462] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 12/03/2020] [Accepted: 12/08/2020] [Indexed: 12/13/2022] Open
Abstract
Penicillium, one of the most common fungi occurring in a diverse range of habitats, has a worldwide distribution and a large economic impact on human health. Hundreds of the species belonging to this genus cause disastrous decay in food crops and are able to produce a varied range of secondary metabolites, from which we can distinguish harmful mycotoxins. Some Penicillium species are considered to be important producers of patulin and ochratoxin A, two well-known mycotoxins. The production of these mycotoxins and other secondary metabolites is controlled and regulated by different mechanisms. The aim of this review is to highlight the different levels of regulation of secondary metabolites in the Penicillium genus.
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Affiliation(s)
- Christelle El Hajj Assaf
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UPS, 31027 Toulouse, France; (C.E.H.A.); (C.Z.-S.); (N.T.); (I.P.O.); (S.L.)
- Institute for Agricultural and Fisheries Research (ILVO), member of Food2Know, Brusselsesteenweg 370, 9090 Melle, Belgium
| | - Chrystian Zetina-Serrano
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UPS, 31027 Toulouse, France; (C.E.H.A.); (C.Z.-S.); (N.T.); (I.P.O.); (S.L.)
| | - Nadia Tahtah
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UPS, 31027 Toulouse, France; (C.E.H.A.); (C.Z.-S.); (N.T.); (I.P.O.); (S.L.)
- Centre D’analyse et de Recherche, Unité de Recherche Technologies et Valorisations Agro-Alimentaires, Faculté des Sciences, Université Saint-Joseph, P.O. Box 17-5208, Mar Mikhael, Beirut 1104, Lebanon;
| | - André El Khoury
- Centre D’analyse et de Recherche, Unité de Recherche Technologies et Valorisations Agro-Alimentaires, Faculté des Sciences, Université Saint-Joseph, P.O. Box 17-5208, Mar Mikhael, Beirut 1104, Lebanon;
| | - Ali Atoui
- Laboratory of Microbiology, Department of Life and Earth Sciences, Faculty of Sciences I, Lebanese University, Hadath Campus, P.O. Box 5, Beirut 1104, Lebanon;
| | - Isabelle P. Oswald
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UPS, 31027 Toulouse, France; (C.E.H.A.); (C.Z.-S.); (N.T.); (I.P.O.); (S.L.)
| | - Olivier Puel
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UPS, 31027 Toulouse, France; (C.E.H.A.); (C.Z.-S.); (N.T.); (I.P.O.); (S.L.)
| | - Sophie Lorber
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UPS, 31027 Toulouse, France; (C.E.H.A.); (C.Z.-S.); (N.T.); (I.P.O.); (S.L.)
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27
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Abreu SC, Hampton TH, Hoffman E, Dearborn J, Ashare A, Singh Sidhu K, Matthews DE, McKenna DH, Amiel E, Barua J, Krasnodembskaya A, English K, Mahon B, Dos Santos C, Cruz FF, Chambers DC, Liu KD, Matthay MA, Cramer RA, Stanton BA, Rocco PRM, Wargo MJ, Weiss DJ, Rolandsson Enes S. Differential effects of the cystic fibrosis lung inflammatory environment on mesenchymal stromal cells. Am J Physiol Lung Cell Mol Physiol 2020; 319:L908-L925. [PMID: 32901521 PMCID: PMC7792680 DOI: 10.1152/ajplung.00218.2020] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 08/14/2020] [Accepted: 08/23/2020] [Indexed: 12/23/2022] Open
Abstract
Growing evidence demonstrates that human mesenchymal stromal cells (MSCs) modify their in vivo anti-inflammatory actions depending on the specific inflammatory environment encountered. Understanding this better is crucial to refine MSC-based cell therapies for lung and other diseases. Using acute exacerbations of cystic fibrosis (CF) lung disease as a model, the effects of ex vivo MSC exposure to clinical bronchoalveolar lavage fluid (BALF) samples, as a surrogate for the in vivo clinical lung environment, on MSC viability, gene expression, secreted cytokines, and mitochondrial function were compared with effects of BALF collected from healthy volunteers. CF BALF samples that cultured positive for Aspergillus sp. (Asp) induced rapid MSC death, usually within several hours of exposure. Further analyses suggested the fungal toxin gliotoxin as a potential mediator contributing to CF BALF-induced MSC death. RNA sequencing analyses of MSCs exposed to either Asp+ or Asp- CF BALF samples identified a number of differentially expressed transcripts, including those involved in interferon signaling, antimicrobial gene expression, and cell death. Toxicity did not correlate with bacterial lung infections. These results suggest that the potential use of MSC-based cell therapies for CF or other lung diseases may not be warranted in the presence of Aspergillus.
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Affiliation(s)
- Soraia C Abreu
- Department of Medicine, Larner College of Medicine, University of Vermont, Burlington, Vermont
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Thomas H Hampton
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire
| | - Evan Hoffman
- Department of Medicine, Larner College of Medicine, University of Vermont, Burlington, Vermont
| | - Jacob Dearborn
- Department of Medicine, Larner College of Medicine, University of Vermont, Burlington, Vermont
| | - Alix Ashare
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire
- Section of Pulmonary and Critical Care Medicine, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | | | - Dwight E Matthews
- Department of Medicine, Larner College of Medicine, University of Vermont, Burlington, Vermont
- Department of Chemistry, University of Vermont, Burlington, Vermont
| | - David H McKenna
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, Minnesota
| | - Eyal Amiel
- Department of Biomedical and Health Sciences, College of Nursing and Health Sciences, University of Vermont, Burlington, Vermont
| | - Jayita Barua
- Division of Pulmonary Disease and Critical Care, University of Vermont, and The Vermont Lung Center, Burlington, Vermont
| | - Anna Krasnodembskaya
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University of Belfast, Belfast, United Kingdom
| | - Karen English
- Cellular Immunology Laboratory, Biology Department, Human Health Research Institute, Maynooth University, Maynooth, Ireland
| | - Bernard Mahon
- Immunology & Cell Biology Laboratory, Biology Department, Human Health Research Institute, Maynooth University, Maynooth, Ireland
| | - Claudia Dos Santos
- Departments of Medicine and Critical Care Medicine and the Keenan Research Center for Biomedical Science, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Fernanda F Cruz
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
- National Institute of Science and Technology for Regenerative Medicine, Rio de Janeiro, Brazil
| | - Daniel C Chambers
- School of Medicine, University of Queensland, Brisbane, Queensland, Australia
- Queenland Lung Transplant Service, The Prince Charles Hospital, Brisbane, Queensland, Australia
| | - Kathleen D Liu
- Departments of Medicine and Anesthesiology and the Cardiovascular Research Institute, University of California, San Francisco, California
| | - Michael A Matthay
- Departments of Medicine and Anesthesiology and the Cardiovascular Research Institute, University of California, San Francisco, California
| | - Robert A Cramer
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire
| | - Bruce A Stanton
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire
| | - Patricia R M Rocco
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
- National Institute of Science and Technology for Regenerative Medicine, Rio de Janeiro, Brazil
| | - Matthew J Wargo
- Department of Microbiology & Molecular Genetics, Larner College of Medicine, University of Vermont, Burlington, Vermont
| | - Daniel J Weiss
- Department of Medicine, Larner College of Medicine, University of Vermont, Burlington, Vermont
| | - Sara Rolandsson Enes
- Department of Medicine, Larner College of Medicine, University of Vermont, Burlington, Vermont
- Department of Experimental Medical Science, Lung Biology Unit, Lund University, Lund, Sweden
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28
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Ries LNA, Pardeshi L, Dong Z, Tan K, Steenwyk JL, Colabardini AC, Ferreira Filho JA, de Castro PA, Silva LP, Preite NW, Almeida F, de Assis LJ, dos Santos RAC, Bowyer P, Bromley M, Owens RA, Doyle S, Demasi M, Hernández DCR, Netto LES, Pupo MT, Rokas A, Loures FV, Wong KH, Goldman GH. The Aspergillus fumigatus transcription factor RglT is important for gliotoxin biosynthesis and self-protection, and virulence. PLoS Pathog 2020; 16:e1008645. [PMID: 32667960 PMCID: PMC7384679 DOI: 10.1371/journal.ppat.1008645] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 07/27/2020] [Accepted: 05/19/2020] [Indexed: 12/21/2022] Open
Abstract
Aspergillus fumigatus is an opportunistic fungal pathogen that secretes an array of immune-modulatory molecules, including secondary metabolites (SMs), which contribute to enhancing fungal fitness and growth within the mammalian host. Gliotoxin (GT) is a SM that interferes with the function and recruitment of innate immune cells, which are essential for eliminating A. fumigatus during invasive infections. We identified a C6 Zn cluster-type transcription factor (TF), subsequently named RglT, important for A. fumigatus oxidative stress resistance, GT biosynthesis and self-protection. RglT regulates the expression of several gli genes of the GT biosynthetic gene cluster, including the oxidoreductase-encoding gene gliT, by directly binding to their respective promoter regions. Subsequently, RglT was shown to be important for virulence in a chemotherapeutic murine model of invasive pulmonary aspergillosis (IPA). Homologues of RglT and GliT are present in eurotiomycete and sordariomycete fungi, including the non-GT-producing fungus A. nidulans, where a conservation of function was described. Phylogenetically informed model testing led to an evolutionary scenario in which the GliT-based resistance mechanism is ancestral and RglT-mediated regulation of GliT occurred subsequently. In conclusion, this work describes the function of a previously uncharacterised TF in oxidative stress resistance, GT biosynthesis and self-protection in both GT-producing and non-producing Aspergillus species.
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Affiliation(s)
- Laure N. A. Ries
- Faculty of Medicine of Ribeirao Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - Lakhansing Pardeshi
- Genomics and Bioinformatics Core, Faculty of Health Sciences, University of Macau, Macau SAR, China
- Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Zhiqiang Dong
- Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Kaeling Tan
- Genomics and Bioinformatics Core, Faculty of Health Sciences, University of Macau, Macau SAR, China
- Faculty of Health Sciences, University of Macau, Macau SAR, China
- Centre for Precision Medicine and Research and Training, University of Macau, Macau SAR, China
| | - Jacob L. Steenwyk
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States of America
| | - Ana Cristina Colabardini
- Faculty of Pharmaceutical Sciences of Ribeirao Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - Jaire A. Ferreira Filho
- Faculty of Pharmaceutical Sciences of Ribeirao Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - Patricia A. de Castro
- Faculty of Pharmaceutical Sciences of Ribeirao Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - Lilian P. Silva
- Faculty of Pharmaceutical Sciences of Ribeirao Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - Nycolas W. Preite
- Institute of Science and Technology, Federal University of São Paulo, São José dos Campos, Brazil
| | - Fausto Almeida
- Faculty of Medicine of Ribeirao Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - Leandro J. de Assis
- Faculty of Pharmaceutical Sciences of Ribeirao Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - Renato A. C. dos Santos
- Faculty of Pharmaceutical Sciences of Ribeirao Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - Paul Bowyer
- Manchester Fungal Infection Group, Division of Infection, Immunity and Respiratory Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Michael Bromley
- Manchester Fungal Infection Group, Division of Infection, Immunity and Respiratory Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | | | - Sean Doyle
- Department of Biology, Maynooth University, Maynooth, Ireland
| | - Marilene Demasi
- Institute Butantan, Laboratory of Biochemistry and Biophysics, São Paulo, Brazil
| | - Diego C. R. Hernández
- Faculty of Pharmaceutical Sciences of Ribeirao Preto, University of São Paulo, Ribeirão Preto, Brazil
| | | | - Monica T. Pupo
- Faculty of Pharmaceutical Sciences of Ribeirao Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - Antonis Rokas
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States of America
| | - Flavio V. Loures
- Institute of Science and Technology, Federal University of São Paulo, São José dos Campos, Brazil
| | - Koon H. Wong
- Genomics and Bioinformatics Core, Faculty of Health Sciences, University of Macau, Macau SAR, China
- Institute of Translational Medicine, University of Macau, Macau SAR, China
| | - Gustavo H. Goldman
- Faculty of Pharmaceutical Sciences of Ribeirao Preto, University of São Paulo, Ribeirão Preto, Brazil
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29
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Zhang Z, Lu Y, Xu W, Sui L, Du Q, Wang Y, Zhao Y, Li Q. Influence of genetic diversity of seventeen Beauveria bassiana isolates from different hosts on virulence by comparative genomics. BMC Genomics 2020; 21:451. [PMID: 32605539 PMCID: PMC7329388 DOI: 10.1186/s12864-020-06791-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Accepted: 05/20/2020] [Indexed: 12/17/2022] Open
Abstract
Background Beauveria bassiana (B. bassiana) is a famous entomopathogenic fungus that could parasitize on hundreds of insect species, which are being used as an environmentally friendly mycoinsecticide. Nevertheless, the possible effect of genetic diversity of these B. bassiana isolates from different hosts on virulence has not been explored before. In order to explore that issue, we compared the genome sequences among seventeen B. bassiana isolates from 17 different insects using whole genome re-sequencing, with B. bassiana strain ARSEF 2860 as the reference genome. Results There were a total of 10,098 missense mutated genes, 720 positively selected genes were identified in 17 strains of B. bassiana. Among these, two genes with high frequency mutations encode the toxin-producing non-ribosomal peptide synthase (NRPS) protein. Seven genes undergoing positive selection were enriched in the two-component signaling pathway that is known to regulate the fungal toxicity. In addition, the domain changes of three positively selected genes are also directly related to the virulence plasticity. Besides, the functional categorization of mutated genes showed that most of them involved in the biological functions of toxic proteins involved in. Conclusions Based on our data, our results indicate that several mutated genes and positively selected genes may underpin virulence of B. bassiana towards hosts during infection process, which provide an insight into the potential effects of natural variation on the virulence of B. bassiana, which will be useful in screening out potential virulence factors in B. bassiana.
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Affiliation(s)
- Zhengkun Zhang
- Jilin Key Laboratory of Agricultural Microbiology, Key Laboratory of Integrated Pest Management on Crops in Northeast China, Ministry of Agriculture, Changchun, 130033, Jilin Province, P. R. China
| | - Yang Lu
- Jilin Key Laboratory of Agricultural Microbiology, Key Laboratory of Integrated Pest Management on Crops in Northeast China, Ministry of Agriculture, Changchun, 130033, Jilin Province, P. R. China
| | - Wenjing Xu
- Jilin Key Laboratory of Agricultural Microbiology, Key Laboratory of Integrated Pest Management on Crops in Northeast China, Ministry of Agriculture, Changchun, 130033, Jilin Province, P. R. China
| | - Li Sui
- Jilin Key Laboratory of Agricultural Microbiology, Key Laboratory of Integrated Pest Management on Crops in Northeast China, Ministry of Agriculture, Changchun, 130033, Jilin Province, P. R. China
| | - Qian Du
- Jilin Key Laboratory of Agricultural Microbiology, Key Laboratory of Integrated Pest Management on Crops in Northeast China, Ministry of Agriculture, Changchun, 130033, Jilin Province, P. R. China
| | - Yangzhou Wang
- Jilin Key Laboratory of Agricultural Microbiology, Key Laboratory of Integrated Pest Management on Crops in Northeast China, Ministry of Agriculture, Changchun, 130033, Jilin Province, P. R. China
| | - Yu Zhao
- Jilin Key Laboratory of Agricultural Microbiology, Key Laboratory of Integrated Pest Management on Crops in Northeast China, Ministry of Agriculture, Changchun, 130033, Jilin Province, P. R. China
| | - Qiyun Li
- Jilin Key Laboratory of Agricultural Microbiology, Key Laboratory of Integrated Pest Management on Crops in Northeast China, Ministry of Agriculture, Changchun, 130033, Jilin Province, P. R. China.
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Bulgari D, Fiorini L, Gianoncelli A, Bertuzzi M, Gobbi E. Enlightening Gliotoxin Biological System in Agriculturally Relevant Trichoderma spp. Front Microbiol 2020; 11:200. [PMID: 32226413 PMCID: PMC7080844 DOI: 10.3389/fmicb.2020.00200] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 01/28/2020] [Indexed: 01/29/2023] Open
Abstract
Gliotoxin (GT) is a dual fungal secondary metabolite (SM). It displays pleiotropic activities and possesses medicinal properties and biocontrol abilities but, unfortunately, has toxic properties in humans. Various Trichoderma species are used as fungal biological control agents (BCAs), as a sustainable alternative for crop protection worldwide. Among them is Trichoderma virens, a GT-producing fungus. Since no information was available on the genetically coded prerequisites for the production of GT in other Trichoderma spp., genome analyses were carried out in 10 Trichoderma spp. genomes. Moreover, a real-time PCR assay setup ad hoc and high-performance liquid chromatography (HPLC) analyses were employed to understand the GT-producing biological systems in T. virens GV29-8 (TvGv29-8) and Trichoderma afroharzianum T6776 (TaT6776), two relevant biocontrol fungi. The structure of the GT biosynthesis genes (GT-BG) is polymorphic, with two distinct types associated with the ability to produce GT. GliH, a key protein for GT synthesis, is absent in most of the Trichoderma GT biosynthetic pathways, which may be the reason for their inability to produce GT. The GT-BG are expressed in TvGv29-8 as expected, while they are silent in TaT6776. Interestingly, in the GT-non-producing TaT6776, only gliA (putative GT transporter) and gtmA (putative GT S-methyltransferase) were induced by exogenous GT, underlining the ability of this strain to reduce the deleterious effect of the toxin. This ability is confirmed by growth assays and by the detection of the bis-thiomethylated form of GT catalyzed by GtmA in the culture medium supplemented with GT. To the best of our knowledge, this is the first general description of the GT biological system in different Trichoderma spp. as far as the GT-BG content and organization is concerned and a preliminary insight into their functionality.
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Affiliation(s)
- Daniela Bulgari
- Piattaforma di Microbiologia Agroalimentare ed Ambientale (Pi.Mi.A.A.), AgroFood Lab, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Lisa Fiorini
- Piattaforma di Microbiologia Agroalimentare ed Ambientale (Pi.Mi.A.A.), AgroFood Lab, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Alessandra Gianoncelli
- Piattaforma di Proteomica, AgroFood Lab, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Michela Bertuzzi
- Piattaforma di Proteomica, AgroFood Lab, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Emanuela Gobbi
- Piattaforma di Microbiologia Agroalimentare ed Ambientale (Pi.Mi.A.A.), AgroFood Lab, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
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Knowles SL, Mead ME, Silva LP, Raja HA, Steenwyk JL, Goldman GH, Oberlies NH, Rokas A. Gliotoxin, a Known Virulence Factor in the Major Human Pathogen Aspergillus fumigatus, Is Also Biosynthesized by Its Nonpathogenic Relative Aspergillus fischeri. mBio 2020; 11:e03361-19. [PMID: 32047138 PMCID: PMC7018655 DOI: 10.1128/mbio.03361-19] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 01/03/2020] [Indexed: 11/20/2022] Open
Abstract
Aspergillus fumigatus is a major opportunistic human pathogen. Multiple traits contribute to A. fumigatus pathogenicity, including its ability to produce specific secondary metabolites, such as gliotoxin. Gliotoxin is known to inhibit the host immune response, and genetic mutants that inactivate gliotoxin biosynthesis (or secondary metabolism in general) attenuate A. fumigatus virulence. The genome of Aspergillus fischeri, a very close nonpathogenic relative of A. fumigatus, contains a biosynthetic gene cluster that is homologous to the A. fumigatus gliotoxin cluster. However, A. fischeri is not known to produce gliotoxin. To gain further insight into the similarities and differences between the major pathogen A. fumigatus and the nonpathogen A. fischeri, we examined whether A. fischeri strain NRRL 181 biosynthesizes gliotoxin and whether the production of secondary metabolites influences the virulence profile of A. fischeri We found that A. fischeri biosynthesizes gliotoxin under the same conditions as A. fumigatus However, whereas loss of laeA, a master regulator of secondary metabolite production (including gliotoxin biosynthesis), has previously been shown to reduce A. fumigatus virulence, we found that laeA loss (and loss of secondary metabolite production) in A. fischeri does not influence its virulence. These results suggest that LaeA-regulated secondary metabolites are virulence factors in the genomic and phenotypic background of the major pathogen A. fumigatus but are much less important in the background of the nonpathogen A. fischeri Understanding the observed spectrum of pathogenicity across closely related pathogenic and nonpathogenic Aspergillus species will require detailed characterization of their biological, chemical, and genomic similarities and differences.IMPORTANCEAspergillus fumigatus is a major opportunistic fungal pathogen of humans, but most of its close relatives are nonpathogenic. Why is that so? This important, yet largely unanswered, question can be addressed by examining how A. fumigatus and its close nonpathogenic relatives are similar or different with respect to virulence-associated traits. We investigated whether Aspergillus fischeri, a nonpathogenic close relative of A. fumigatus, can produce gliotoxin, a mycotoxin known to contribute to A. fumigatus virulence. We discovered that the nonpathogenic A. fischeri produces gliotoxin under the same conditions as those of the major pathogen A. fumigatus However, we also discovered that, in contrast to what has previously been observed in A. fumigatus, the loss of secondary metabolite production in A. fischeri does not alter its virulence. Our results are consistent with the "cards of virulence" model of opportunistic fungal disease, in which the ability to cause disease stems from the combination ("hand") of virulence factors ("cards") but not from individual factors per se.
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Affiliation(s)
- Sonja L Knowles
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, North Carolina, USA
| | - Matthew E Mead
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Lilian Pereira Silva
- Faculdade de Ciencias Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Huzefa A Raja
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, North Carolina, USA
| | - Jacob L Steenwyk
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Gustavo H Goldman
- Faculdade de Ciencias Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Nicholas H Oberlies
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, North Carolina, USA
| | - Antonis Rokas
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
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Traynor AM, Sheridan KJ, Jones GW, Calera JA, Doyle S. Involvement of Sulfur in the Biosynthesis of Essential Metabolites in Pathogenic Fungi of Animals, Particularly Aspergillus spp.: Molecular and Therapeutic Implications. Front Microbiol 2019; 10:2859. [PMID: 31921039 PMCID: PMC6923255 DOI: 10.3389/fmicb.2019.02859] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 11/25/2019] [Indexed: 12/13/2022] Open
Abstract
Fungal sulfur uptake is required for incorporation into the sidechains of the amino acids cysteine and methionine, and is also essential for the biosynthesis of the antioxidant glutathione (GSH), S-adenosylmethionine (SAM), the key source of methyl groups in cellular transmethylation reactions, and S-adenosylhomocysteine (SAH). Biosynthesis of redox-active gliotoxin in the opportunistic fungal pathogen Aspergillus fumigatus has been elucidated over the past 10 years. Some fungi which produce gliotoxin-like molecular species have undergone unexpected molecular rewiring to accommodate this high-risk biosynthetic process. Specific disruption of gliotoxin biosynthesis, via deletion of gliK, which encodes a γ-glutamyl cyclotransferase, leads to elevated intracellular antioxidant, ergothioneine (EGT), levels, and confirms crosstalk between the biosynthesis of both sulfur-containing moieties. Gliotoxin is ultimately formed by gliotoxin oxidoreductase GliT-mediated oxidation of dithiol gliotoxin (DTG). In fact, DTG is a substrate for both GliT and a bis-thiomethyltransferase, GtmA. GtmA converts DTG to bisdethiobis(methylthio)gliotoxin (BmGT), using 2 mol SAM and resultant SAH must be re-converted to SAM via the action of the Methyl/Met cycle. In the absence of GliT, DTG fluxes via GtmA to BmGT, which results in both SAM depletion and SAH overproduction. Thus, the negative regulation of gliotoxin biosynthesis via GtmA must be counter-balanced by GliT activity to avoid Methyl/Met cycle dysregulation, SAM depletion and trans consequences on global cellular biochemistry in A. fumigatus. DTG also possesses potent Zn2+ chelation properties which positions this sulfur-containing metabolite as a putative component of the Zn2+ homeostasis system within fungi. EGT plays an essential role in high-level redox homeostasis and its presence requires significant consideration in future oxidative stress studies in pathogenic filamentous fungi. In certain filamentous fungi, sulfur is additionally indirectly required for the formation of EGT and the disulfide-bridge containing non-ribosomal peptide, gliotoxin, and related epipolythiodioxopiperazines. Ultimately, interference with emerging sulfur metabolite functionality may represent a new strategy for antifungal drug development.
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Affiliation(s)
- Aimee M Traynor
- Department of Biology, Maynooth University, Maynooth, Ireland
| | | | - Gary W Jones
- Centre for Biomedical Science Research, School of Clinical and Applied Sciences, Leeds Beckett University, Leeds, United Kingdom
| | - José A Calera
- Instituto de Biología Funcional y Genómica (IBFG-CSIC), Universidad de Salamanca, Salamanca, Spain.,Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain
| | - Sean Doyle
- Department of Biology, Maynooth University, Maynooth, Ireland
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Lwin HP, Choi YH, Lee MW, Yu JH, Shin KS. RgsA Attenuates the PKA Signaling, Stress Response, and Virulence in the Human Opportunistic Pathogen Aspergillus fumigatus. Int J Mol Sci 2019; 20:ijms20225628. [PMID: 31717953 PMCID: PMC6888639 DOI: 10.3390/ijms20225628] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 11/05/2019] [Accepted: 11/07/2019] [Indexed: 12/14/2022] Open
Abstract
The regulator of G-protein signaling (RGS) proteins play an important role in upstream control of heterotrimeric G-protein signaling pathways. In the genome of the human opportunistic pathogenic fungus Aspergillus fumigatus, six RGS protein-encoding genes are present. To characterize the rgsA gene predicted to encode a protein with an RGS domain, we generated an rgsA null mutant and observed the phenotypes of the mutant. The deletion (Δ) of rgsA resulted in increased radial growth and enhanced asexual sporulation in both solid and liquid culture conditions. Accordingly, transcripts levels of the key asexual developmental regulators abaA, brlA, and wetA are elevated in the ΔrgsA mutant. Moreover, ΔrgsA resulted in elevated spore germination rates in the absence of a carbon source. The activity of cAMP-dependent protein kinase A (PKA) and mRNA levels of genes encoding PKA signaling elements are elevated by ΔrgsA. In addition, mRNA levels of genes associated with stress-response signaling increased with the lack of rgsA, and the ΔrgsA spores showed enhanced tolerance against oxidative stressors. Comparative transcriptomic analyses revealed that the ΔrgsA mutant showed higher mRNA levels of gliotoxin (GT) biosynthetic genes. Accordingly, the rgsA null mutant exhibited increased production of GT and elevated virulence in the mouse. Conversely, the majority of genes encoding glucan degrading enzymes were down-regulated by ΔrgsA, and endoglucanase activities were reduced. In summary, RgsA plays multiple roles, governing growth, development, stress responses, virulence, and external polymer degradation-likely by attenuating PKA signaling.
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Affiliation(s)
- Hnin Phyu Lwin
- Department of Microbiology, Graduate School, Daejeon University, Daejeon 34520, Korea; (H.P.L.); (Y.-H.C.)
| | - Yong-Ho Choi
- Department of Microbiology, Graduate School, Daejeon University, Daejeon 34520, Korea; (H.P.L.); (Y.-H.C.)
| | - Min-Woo Lee
- Soonchunhyang Institute of Medi-bio Science, Soonchunhyang University, Chungcheongnam-do 31151, Korea;
| | - Jae-Hyuk Yu
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA
- Department of Systems Biotechnology, Konkuk University, Seoul 05029, Korea
- Correspondence: (J.-H.Y.); (K.-S.S.); Tel.: +1-608-262-4696 (J.-H.Y.); +82-42-280-2439 (K.-S.S.); Fax: +1-608-262-2976 (J.-H.Y.); +82-42-280-2608 (K.-S.S.)
| | - Kwang-Soo Shin
- Department of Microbiology, Graduate School, Daejeon University, Daejeon 34520, Korea; (H.P.L.); (Y.-H.C.)
- Correspondence: (J.-H.Y.); (K.-S.S.); Tel.: +1-608-262-4696 (J.-H.Y.); +82-42-280-2439 (K.-S.S.); Fax: +1-608-262-2976 (J.-H.Y.); +82-42-280-2608 (K.-S.S.)
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Baccile JA, Le HH, Pfannenstiel BT, Bok JW, Gomez C, Brandenburger E, Hoffmeister D, Keller NP, Schroeder FC. Diketopiperazine Formation in Fungi Requires Dedicated Cyclization and Thiolation Domains. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201909052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Joshua A. Baccile
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology Cornell University Ithaca NY USA
- Present Address: Division of Chemistry and Chemical Engineering California Institute of Technology Pasadena CA USA
| | - Henry H. Le
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology Cornell University Ithaca NY USA
| | - Brandon T. Pfannenstiel
- Departments of Bacteriology Medical Microbiology and Immunology University of Wisconsin-Madison Madison WI USA
| | - Jin Woo Bok
- Departments of Bacteriology Medical Microbiology and Immunology University of Wisconsin-Madison Madison WI USA
| | - Christian Gomez
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology Cornell University Ithaca NY USA
| | - Eileen Brandenburger
- Department of Pharmaceutical Microbiology Hans-Knöll-Institute Friedrich Schiller University Jena Germany
| | - Dirk Hoffmeister
- Department of Pharmaceutical Microbiology Hans-Knöll-Institute Friedrich Schiller University Jena Germany
| | - Nancy P. Keller
- Departments of Bacteriology Medical Microbiology and Immunology University of Wisconsin-Madison Madison WI USA
| | - Frank C. Schroeder
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology Cornell University Ithaca NY USA
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Baccile JA, Le HH, Pfannenstiel BT, Bok JW, Gomez C, Brandenburger E, Hoffmeister D, Keller NP, Schroeder FC. Diketopiperazine Formation in Fungi Requires Dedicated Cyclization and Thiolation Domains. Angew Chem Int Ed Engl 2019; 58:14589-14593. [PMID: 31342608 PMCID: PMC6764874 DOI: 10.1002/anie.201909052] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Indexed: 01/08/2023]
Abstract
Cyclization of linear dipeptidyl precursors derived from nonribosomal peptide synthetases (NRPSs) into 2,5-diketopiperazines (DKPs) is a crucial step in the biosynthesis of a large number of bioactive natural products. However, the mechanism of DKP formation in fungi has remained unclear, despite extensive studies of their biosyntheses. Here we show that DKP formation en route to the fungal virulence factor gliotoxin requires a seemingly extraneous couplet of condensation (C) and thiolation (T) domains in the NRPS GliP. In vivo truncation of GliP to remove the CT couplet or just the T domain abrogated production of gliotoxin and all other gli pathway metabolites. Point mutation of conserved active sites in the C and T domains diminished cyclization activity of GliP in vitro and abolished gliotoxin biosynthesis in vivo. Verified NRPSs of other fungal DKPs terminate with similar CT domain couplets, suggesting a conserved strategy for DKP biosynthesis by fungal NRPSs.
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Affiliation(s)
- Joshua A Baccile
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
- Present Address: Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Henry H Le
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
| | - Brandon T Pfannenstiel
- Departments of Bacteriology, Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, USA
| | - Jin Woo Bok
- Departments of Bacteriology, Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, USA
| | - Christian Gomez
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
| | - Eileen Brandenburger
- Department of Pharmaceutical Microbiology, Hans-Knöll-Institute, Friedrich Schiller University, Jena, Germany
| | - Dirk Hoffmeister
- Department of Pharmaceutical Microbiology, Hans-Knöll-Institute, Friedrich Schiller University, Jena, Germany
| | - Nancy P Keller
- Departments of Bacteriology, Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, USA
| | - Frank C Schroeder
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
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Zhang C, Chen F, Liu X, Han X, Hu Y, Su X, Chen Y, Sun Y, Han L. Gliotoxin Induces Cofilin Phosphorylation to Promote Actin Cytoskeleton Dynamics and Internalization of Aspergillus fumigatus Into Type II Human Pneumocyte Cells. Front Microbiol 2019; 10:1345. [PMID: 31275272 PMCID: PMC6591310 DOI: 10.3389/fmicb.2019.01345] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 05/29/2019] [Indexed: 01/27/2023] Open
Abstract
Aspergillus fumigatus is able to internalize into lung epithelial cells to escape from immune attack for further dissemination. We previously reported that gliotoxin, a major mycotoxin of A. fumigatus, promotes this internalization; however, the mechanism remained unclear. Here, we report that gliotoxin is able to induce cofilin phosphorylation in A549 type II human pneumocytes. Either too high or too low a level of cofilin phosphorylation blocked the gliotoxin-induced actin cytoskeleton rearrangement and A. fumigatus internalization. LIM domain kinase 1 (LIMK1) and its upstream small GTPases (Cdc42 and RhoA, but not Rac1) predominantly mediated the gliotoxin-induced cofilin phosphorylation and A. fumigatus internalization. Simultaneously, gliotoxin significantly stimulated an increase in cAMP; however, adding an antagonist of PKA did not block gliotoxin-induced A. fumigatus internalization. In vivo, exogenous gliotoxin helped gliotoxin synthesis deficient strain gliPΔ invade into the lung tissue and the lung fungal burden increased markedly in immunosuppressed mice. In conclusion, these data revealed a novel role of gliotoxin in inducing cofilin phosphorylation mostly through the Cdc42/RhoA-LIMK1 signaling pathway to promote actin cytoskeleton rearrangement and internalization of A. fumigatus into type II human pneumocytes.
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Affiliation(s)
- Changjian Zhang
- Chinese PLA Center for Disease Control and Prevention, Beijing, China.,Academy of Military Medical Sciences, Beijing, China
| | - Fangyan Chen
- Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Xiaoyu Liu
- Chinese PLA Center for Disease Control and Prevention, Beijing, China.,Academy of Military Medical Sciences, Beijing, China
| | - Xuelin Han
- Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Yingsong Hu
- Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Xueting Su
- Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Yong Chen
- Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Yansong Sun
- Academy of Military Medical Sciences, Beijing, China
| | - Li Han
- Chinese PLA Center for Disease Control and Prevention, Beijing, China
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Thammahong A, Dhingra S, Bultman KM, Kerkaert JD, Cramer RA. An Ssd1 Homolog Impacts Trehalose and Chitin Biosynthesis and Contributes to Virulence in Aspergillus fumigatus. mSphere 2019; 4:e00244-19. [PMID: 31068436 PMCID: PMC6506620 DOI: 10.1128/msphere.00244-19] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 04/24/2019] [Indexed: 12/24/2022] Open
Abstract
Regulation of fungal cell wall biosynthesis is critical to maintain cell wall integrity in dynamic fungal infection microenvironments. Genes involved in this response that impact fungal fitness and host immune responses remain to be fully defined. In this study, we observed that a yeast ssd1 homolog, ssdA, in the filamentous fungus Aspergillus fumigatus is involved in trehalose and cell wall homeostasis. An ssdA null mutant strain exhibited an increase in trehalose levels and a reduction in fungal colony growth rate. In contrast, overexpression of ssdA perturbed trehalose biosynthesis and reduced germination of conidia. The ssdA null mutant strain was more resistant to cell wall-perturbing agents, while overexpression of ssdA increased sensitivity. Overexpression of ssdA significantly increased chitin levels, and both loss and overexpression of ssdA altered subcellular localization of the class V chitin synthase CsmA. Strikingly, overexpression of ssdA abolished adherence to abiotic surfaces and severely attenuated the virulence of A. fumigatus in a murine model of invasive pulmonary aspergillosis. Despite the severe in vitro fitness defects observed upon loss of ssdA, neither surface adherence nor murine survival was impacted. In conclusion, A. fumigatus SsdA plays a critical role in cell wall homeostasis impacting A. fumigatus-host interactions.IMPORTANCE The incidence of life-threatening infections caused by the filamentous fungus Aspergillus fumigatus is increasing along with an increase in the number of fungal strains resistant to contemporary antifungal therapies. The fungal cell wall and the associated carbohydrates required for its synthesis and maintenance are attractive drug targets given that many genes encoding proteins involved in cell wall biosynthesis and integrity are absent in humans. Importantly, genes and associated cell wall biosynthesis and homeostasis regulatory pathways remain to be fully defined in A. fumigatus In this report, we identify SsdA as an important component of trehalose and fungal cell wall biosynthesis in A. fumigatus that consequently impacts the host immune response and fungal virulence in animal models of infection.
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Affiliation(s)
- Arsa Thammahong
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Sourabh Dhingra
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Katherine M Bultman
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Joshua D Kerkaert
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Robert A Cramer
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
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Mc Namara L, Dolan SK, Walsh JMD, Stephens JC, Glare TR, Kavanagh K, Griffin CT. Oosporein, an abundant metabolite in Beauveria caledonica, with a feedback induction mechanism and a role in insect virulence. Fungal Biol 2019; 123:601-610. [PMID: 31345414 DOI: 10.1016/j.funbio.2019.01.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 12/14/2018] [Accepted: 01/22/2019] [Indexed: 12/11/2022]
Abstract
Oosporein was first identified from the insect pathogen Beauveria bassiana >50 y ago. Here, we investigate the insecticidal, anti-feedant and immunomodulation effects of oosporein produced by Beauveria caledonica on the forestry pest Hylobius abietis and model insect Galleria mellonella. We report a novel feedback induction mechanism regulating oosporein production in B. caledonica; exogenous oosporein induces the expression of the oosporein cluster, leading to increased abundance of oosporein biosynthetic enzymes, as shown by label-free quantitative proteomics. Oosporein did not have an anti-feedant effect on H. abietis adults - on the contrary, insects exposed to oosporein-treated food fed more than those exposed to untreated food only. Injected oosporein did not kill insect larvae but increased susceptibility of H. abietis to a subsequent infection. Oosporein did not act as a contact toxin on H. abietis adults and G. mellonella larvae at the concentrations tested. Therefore, it appears that oosporein promotes infection rather than directly killing insects; this could be mediated both by a reduction in haemocyte numbers and by alterations to the humoral immune system. This work makes a case for future research into the potential use of B. caledonica as a biocontrol agent through combinations with oosporein or with enhanced production of oosporein.
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Affiliation(s)
- Louise Mc Namara
- Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland; Teagasc, Oak Park, Crop Research Centre, Co. Carlow, Ireland.
| | - Stephen K Dolan
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK
| | - John M D Walsh
- Department of Chemistry, Maynooth University, Maynooth, Co. Kildare, Ireland
| | - John C Stephens
- Department of Chemistry, Maynooth University, Maynooth, Co. Kildare, Ireland
| | - Travis R Glare
- Bio-Protection Research Centre, Lincoln, University Lincoln, New Zealand
| | - Kevin Kavanagh
- Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland
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40
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Arias M, Santiago L, Vidal-García M, Redrado S, Lanuza P, Comas L, Domingo MP, Rezusta A, Gálvez EM. Preparations for Invasion: Modulation of Host Lung Immunity During Pulmonary Aspergillosis by Gliotoxin and Other Fungal Secondary Metabolites. Front Immunol 2018; 9:2549. [PMID: 30459771 PMCID: PMC6232612 DOI: 10.3389/fimmu.2018.02549] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 10/17/2018] [Indexed: 12/12/2022] Open
Abstract
Pulmonary aspergillosis is a severe infectious disease caused by some members of the Aspergillus genus, that affects immunocompetent as well as immunocompromised patients. Among the different disease forms, Invasive Aspergillosis is the one causing the highest mortality, mainly, although not exclusively, affecting neutropenic patients. This genus is very well known by humans, since different sectors like pharmaceutical or food industry have taken advantage of the biological activity of some molecules synthetized by the fungus, known as secondary metabolites, including statins, antibiotics, fermentative compounds or colorants among others. However, during infection, in response to a hostile host environment, the fungal secondary metabolism is activated, producing different virulence factors to increase its survival chances. Some of these factors also contribute to fungal dissemination and invasion of adjacent and distant organs. Among the different secondary metabolites produced by Aspergillus spp. Gliotoxin (GT) is the best known and better characterized virulence factor. It is able to generate reactive oxygen species (ROS) due to the disulfide bridge present in its structure. It also presents immunosuppressive activity related with its ability to kill mammalian cells and/or inactivate critical immune signaling pathways like NFkB. In this comprehensive review, we will briefly give an overview of the lung immune response against Aspergillus as a preface to analyse the effect of different secondary metabolites on the host immune response, with a special attention to GT. We will discuss the results reported in the literature on the context of the animal models employed to analyse the role of GT as virulence factor, which is expected to greatly depend on the immune status of the host: why should you hide when nobody is seeking for you? Finally, GT immunosuppressive activity will be related with different human diseases predisposing to invasive aspergillosis in order to have a global view on the potential of GT to be used as a target to treat IA.
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Affiliation(s)
- Maykel Arias
- Instituto de Carboquímica ICB-CSIC, Zaragoza, Spain
- Immune Effector Cells Group, Aragón Health Research Institute (IIS Aragón), Biomedical Research Centre of Aragón (CIBA), Zaragoza, Spain
| | - Llipsy Santiago
- Immune Effector Cells Group, Aragón Health Research Institute (IIS Aragón), Biomedical Research Centre of Aragón (CIBA), Zaragoza, Spain
- Department of Biochemistry and Molecular and Cell Biology, Fac. Ciencias, University of Zaragoza, Zaragoza, Spain
| | - Matxalen Vidal-García
- Immune Effector Cells Group, Aragón Health Research Institute (IIS Aragón), Biomedical Research Centre of Aragón (CIBA), Zaragoza, Spain
- Servicio de Microbiología - Hospital Universitario Miguel Servet, Zaragoza, Spain
| | | | - Pilar Lanuza
- Immune Effector Cells Group, Aragón Health Research Institute (IIS Aragón), Biomedical Research Centre of Aragón (CIBA), Zaragoza, Spain
- Department of Biochemistry and Molecular and Cell Biology, Fac. Ciencias, University of Zaragoza, Zaragoza, Spain
| | - Laura Comas
- Instituto de Carboquímica ICB-CSIC, Zaragoza, Spain
- Immune Effector Cells Group, Aragón Health Research Institute (IIS Aragón), Biomedical Research Centre of Aragón (CIBA), Zaragoza, Spain
- Department of Biochemistry and Molecular and Cell Biology, Fac. Ciencias, University of Zaragoza, Zaragoza, Spain
| | | | - Antonio Rezusta
- Servicio de Microbiología - Hospital Universitario Miguel Servet, Zaragoza, Spain
- Department of Microbiology, Preventive Medicine and Public Health, University of Zaragoza, Zaragoza, Spain
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Vidal-García M, Redrado S, Domingo MP, Marquina P, Colmenarejo C, Meis JF, Rezusta A, Pardo J, Galvez EM. Production of the Invasive Aspergillosis Biomarker Bis(methylthio)gliotoxin Within the Genus Aspergillus: In Vitro and in Vivo Metabolite Quantification and Genomic Analysis. Front Microbiol 2018; 9:1246. [PMID: 29946309 PMCID: PMC6006755 DOI: 10.3389/fmicb.2018.01246] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 05/23/2018] [Indexed: 01/12/2023] Open
Abstract
Gliotoxin (GT) is a fungal secondary metabolite that has attracted great interest due to its high biological activity since it was discovered by the 1930s. An inactive derivative of this molecule, bis(methylthio)gliotoxin (bmGT), has been proposed as an invasive aspergillosis (IA) biomarker. Nevertheless, studies regarding bmGT production among common opportunistic fungi, including the Aspergillus genus, are scarce and sometimes discordant. As previously reported, bmGT is produced from GT by a methyl-transferase, named as GtmA, as a negative feedback regulatory system of GT production. In order to analyze the potential of bmGT detection to enable identification of infections caused by different members of the Aspergillus genus we have assessed bmGT production within the genus Aspergillus, including A, fumigatus, A. niger, A. nidulans, and A. flavus, and its correlation with gtmA presence. In order to validate the relevance of our in vitro findings, we compared bmGT during in vitro culture with the presence of bmGT in sera of patients from whom the Aspergillus spp. were isolated. Our results indicate that most A. fumigatus isolates produce GT and bmGT both in vitro and in vivo. In contrast, A. niger and A. nidulans were not able to produce GT or bmGT, although A. niger produced bmGT from a exogenous GT source. The frequency and amount of bmGT production in A. terreus and A. flavus isolates in vitro was lower than in A. fumigatus. Our results suggest that this defect could be related to the in vitro culture conditions, since isolates that did not produce bmGT in vitro were able to synthetize it in vivo. In summary, our study indicates that bmGT could be very useful to specifically detect the presence of A. fumigatus, the most prevalent agent causing IA. Concerning A. terreus and A. flavus a higher number of analyses from sera from infected patients will be required to reach a useful conclusion.
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Affiliation(s)
- Matxalen Vidal-García
- Centro de Investigación Biomédica de Aragón, Instituto de Investigación Sanitaria Aragón, Zaragoza, Spain.,Hospital Universitario Miguel Servet, Zaragoza, Spain
| | | | | | | | | | - Jacques F Meis
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, Netherlands.,Department of Medical Microbiology and Infectious Diseases, Canisius Wilhelmina Hospital, Nijmegen, Netherlands
| | - Antonio Rezusta
- Hospital Universitario Miguel Servet, Zaragoza, Spain.,Departamento de Microbiología, Medicina Preventiva y Salud Pública, Universidad de Zaragoza, Zaragoza, Spain
| | - Julian Pardo
- Centro de Investigación Biomédica de Aragón, Instituto de Investigación Sanitaria Aragón, Zaragoza, Spain.,Fundacion Agencia Aragonesa para la Investigacion y el Desarrollo, Zaragoza, Spain.,Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, Zaragoza, Spain.,Instituto de Nanociencia de Aragón, Zaragoza, Spain
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Discovery and Biosynthesis of the Antibiotic Bicyclomycin in Distantly Related Bacterial Classes. Appl Environ Microbiol 2018; 84:AEM.02828-17. [PMID: 29500259 PMCID: PMC5930311 DOI: 10.1128/aem.02828-17] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 02/21/2018] [Indexed: 01/23/2023] Open
Abstract
Bicyclomycin (BCM) is a clinically promising antibiotic that is biosynthesized by Streptomyces cinnamoneus DSM 41675. BCM is structurally characterized by a core cyclo(l-Ile-l-Leu) 2,5-diketopiperazine (DKP) that is extensively oxidized. Here, we identify the BCM biosynthetic gene cluster, which shows that the core of BCM is biosynthesized by a cyclodipeptide synthase, and the oxidative modifications are introduced by five 2-oxoglutarate-dependent dioxygenases and one cytochrome P450 monooxygenase. The discovery of the gene cluster enabled the identification of BCM pathways encoded by the genomes of hundreds of Pseudomonas aeruginosa isolates distributed globally, and heterologous expression of the pathway from P. aeruginosa SCV20265 demonstrated that the product is chemically identical to BCM produced by S. cinnamoneus. Overall, putative BCM gene clusters have been found in at least seven genera spanning Actinobacteria and Proteobacteria (Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria). This represents a rare example of horizontal gene transfer of an intact biosynthetic gene cluster across such distantly related bacteria, and we show that these gene clusters are almost always associated with mobile genetic elements. IMPORTANCE Bicyclomycin is the only natural product antibiotic that selectively inhibits the transcription termination factor Rho. This mechanism of action, combined with its proven biological safety and its activity against clinically relevant Gram-negative bacterial pathogens, makes it a very promising antibiotic candidate. Here, we report the identification of the bicyclomycin biosynthetic gene cluster in the known bicyclomycin-producing organism Streptomyces cinnamoneus, which will enable the engineered production of new bicyclomycin derivatives. The identification of this gene cluster also led to the discovery of hundreds of bicyclomycin pathways encoded in highly diverse bacteria, including in the opportunistic pathogen Pseudomonas aeruginosa. This wide distribution of a complex biosynthetic pathway is very unusual and provides an insight into how a pathway for an antibiotic can be transferred between diverse bacteria.
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43
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Saleh AA, Jones GW, Tinley FC, Delaney SF, Alabbadi SH, Fenlon K, Doyle S, Owens RA. Systems impact of zinc chelation by the epipolythiodioxopiperazine dithiol gliotoxin in Aspergillus fumigatus: a new direction in natural product functionality. Metallomics 2018; 10:854-866. [DOI: 10.1039/c8mt00052b] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Dithiol gliotoxin (DTG) is a zinc chelator and an inability to dissipate DTG in Aspergillus fumigatus is associated with multiple impacts which are linked to zinc chelation.
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Affiliation(s)
| | - Gary W. Jones
- Department of Biology
- Maynooth University
- Co. Kildare
- Ireland
- Centre for Biomedical Research
| | | | | | | | - Keith Fenlon
- Department of Biology
- Maynooth University
- Co. Kildare
- Ireland
| | - Sean Doyle
- Department of Biology
- Maynooth University
- Co. Kildare
- Ireland
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44
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Liu H, Xu W, Solis NV, Woolford C, Mitchell AP, Filler SG. Functional convergence of gliP and aspf1 in Aspergillus fumigatus pathogenicity. Virulence 2018; 9:1062-1073. [PMID: 30052103 PMCID: PMC6086310 DOI: 10.1080/21505594.2018.1482182] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 05/25/2018] [Indexed: 10/28/2022] Open
Abstract
Gliotoxin contributes to the virulence of the fungus Aspergillus fumigatus in non-neutropenic mice that are immunosuppressed with corticosteroids. To investigate how the absence of gliotoxin affects both the fungus and the host, we used a nanoString nCounter to analyze their transcriptional responses during pulmonary infection of a non-neutropenic host with a gliotoxin-deficient ΔgliP mutant. We found that the ΔgliP mutation led to increased expression of aspf1, which specifies a secreted ribotoxin. Prior studies have shown that aspf1, like gliP, is not required for virulence in a neutropenic infection model, but its role in a non-neutropenic infection model has not been fully investigated. To investigate the functional significance of this up-regulation of aspf1, a Δaspf1 single mutant and a Δaspf1 ΔgliP double mutant were constructed. Both Δaspf1 and ΔgliP single mutants had reduced lethality in non-neutropenic mice, and a Δaspf1 ΔgliP double mutant had a greater reduction in lethality than either single mutant. Analysis of mice infected with these mutants indicated that the presence of gliP is associated with massive apoptosis of leukocytes at the foci of infection and inhibition of chemokine production. Also, the combination of gliP and aspf1 is associated with suppression of CXCL1 chemokine expression. Thus, aspf1 contributes to A. fumigatus pathogenicity in non-neutropenic mice and its up-regulation in the ΔgliP mutant may partially compensate for the absence of gliotoxin. ABBREVIATIONS PAS: periodic acid-Schiff; PBS: phosphate buffered saline; ROS: reactive oxygen species; TUNEL: terminal deoxynucleotidyl transferase dUTP nick-end labeling.
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Affiliation(s)
- Hong Liu
- Division of Infectious Diseases, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Wenjie Xu
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Norma V. Solis
- Division of Infectious Diseases, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Carol Woolford
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Aaron P. Mitchell
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Scott G. Filler
- Division of Infectious Diseases, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
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45
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Dolan SK, Bock T, Hering V, Owens RA, Jones GW, Blankenfeldt W, Doyle S. Structural, mechanistic and functional insight into gliotoxin bis-thiomethylation in Aspergillus fumigatus. Open Biol 2017; 7:rsob.160292. [PMID: 28179499 PMCID: PMC5356443 DOI: 10.1098/rsob.160292] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 01/11/2017] [Indexed: 01/02/2023] Open
Abstract
Gliotoxin is an epipolythiodioxopiperazine (ETP) class toxin, contains a disulfide bridge that mediates its toxic effects via redox cycling and is produced by the opportunistic fungal pathogen Aspergillus fumigatus Self-resistance against gliotoxin is effected by the gliotoxin oxidase GliT, and attenuation of gliotoxin biosynthesis is catalysed by gliotoxin S-methyltransferase GtmA. Here we describe the X-ray crystal structures of GtmA-apo (1.66 Å), GtmA complexed to S-adenosylhomocysteine (1.33 Å) and GtmA complexed to S-adenosylmethionine (2.28 Å), providing mechanistic insights into this important biotransformation. We further reveal that simultaneous elimination of the ability of A. fumigatus to dissipate highly reactive dithiol gliotoxin, via deletion of GliT and GtmA, results in the most significant hypersensitivity to exogenous gliotoxin observed to date. Indeed, quantitative proteomic analysis of ΔgliT::ΔgtmA reveals an uncontrolled over-activation of the gli-cluster upon gliotoxin exposure. The data presented herein reveal, for the first time, the extreme risk associated with intracellular dithiol gliotoxin biosynthesis-in the absence of an efficient dismutation capacity. Significantly, a previously concealed protective role for GtmA and functionality of ETP bis-thiomethylation as an ancestral protection strategy against dithiol compounds is now evident.
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Affiliation(s)
- Stephen K Dolan
- Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland
| | - Tobias Bock
- Helmholtz Centre for Infection Research, Structure and Function of Proteins, Inhoffenstraße 7, 38124 Braunschweig, Germany
| | - Vanessa Hering
- Helmholtz Centre for Infection Research, Structure and Function of Proteins, Inhoffenstraße 7, 38124 Braunschweig, Germany
| | - Rebecca A Owens
- Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland
| | - Gary W Jones
- Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland
| | - Wulf Blankenfeldt
- Helmholtz Centre for Infection Research, Structure and Function of Proteins, Inhoffenstraße 7, 38124 Braunschweig, Germany .,Institute of Biochemistry, Biotechnology and Bioinformatics, Technische Universität Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany
| | - Sean Doyle
- Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland
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Valiante V. The Cell Wall Integrity Signaling Pathway and Its Involvement in Secondary Metabolite Production. J Fungi (Basel) 2017; 3:jof3040068. [PMID: 29371582 PMCID: PMC5753170 DOI: 10.3390/jof3040068] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 12/01/2017] [Accepted: 12/05/2017] [Indexed: 12/21/2022] Open
Abstract
The fungal cell wall is the external and first layer that fungi use to interact with the environment. Every stress signal, before being translated into an appropriate stress response, needs to overtake this layer. Many signaling pathways are involved in translating stress signals, but the cell wall integrity (CWI) signaling pathway is the one responsible for the maintenance and biosynthesis of the fungal cell wall. In fungi, the CWI signal is composed of a mitogen-activated protein kinase (MAPK) module. After the start of the phosphorylation cascade, the CWI signal induces the expression of cell-wall-related genes. However, the function of the CWI signal is not merely the activation of cell wall biosynthesis, but also the regulation of expression and production of specific molecules that are used by fungi to better compete in the environment. These molecules are normally defined as secondary metabolites or natural products. This review is focused on secondary metabolites affected by the CWI signal pathway with a special focus on relevant natural products such as melanins, mycotoxins, and antibacterial compounds.
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Affiliation(s)
- Vito Valiante
- Leibniz Research Group Biobricks of Microbial Natural Product Syntheses, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute (HKI), Beutenberg Strasse 11a, 07745 Jena, Germany.
- Department of General Microbiology and Microbial Genetics, Institute of Microbiology, Faculty of Biology and Pharmacy, Friedrich Schiller University Jena, Neugasse 24, 07743 Jena, Germany.
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Bignell E, Cairns TC, Throckmorton K, Nierman WC, Keller NP. Secondary metabolite arsenal of an opportunistic pathogenic fungus. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2016.0023. [PMID: 28080993 DOI: 10.1098/rstb.2016.0023] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/26/2016] [Indexed: 12/31/2022] Open
Abstract
Aspergillus fumigatus is a versatile fungus able to successfully exploit diverse environments from mammalian lungs to agricultural waste products. Among its many fitness attributes are dozens of genetic loci containing biosynthetic gene clusters (BGCs) producing bioactive small molecules (often referred to as secondary metabolites or natural products) that provide growth advantages to the fungus dependent on environment. Here we summarize the current knowledge of these BGCs-18 of which can be named to product-their expression profiles in vivo, and which BGCs may enhance virulence of this opportunistic human pathogen. Furthermore, we find extensive evidence for the presence of many of these BGCs, or similar BGCs, in distantly related genera including the emerging pathogen Pseudogymnoascus destructans, the causative agent of white-nose syndrome in bats, and suggest such BGCs may be predictive of pathogenic potential in other fungi.This article is part of the themed issue 'Tackling emerging fungal threats to animal health, food security and ecosystem resilience'.
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Affiliation(s)
- Elaine Bignell
- Manchester Fungal Infection Group, Institute of Inflammation and Repair, 2.24 Core Technology Facility, Grafton Street, Manchester, M13 9NT, UK
| | - Timothy C Cairns
- Department of Applied and Molecular Microbiology, Institute of Biotechnology, Berlin University of Technology, Gustav-Meyer-Allee 25, 13355 Berlin, Germany
| | - Kurt Throckmorton
- Department of Bacteriology, University of Wisconsin, Madison, WI 53706, USA
| | | | - Nancy P Keller
- Department of Bacteriology, University of Wisconsin, Madison, WI 53706, USA, .,Department of Medical Microbiology, University of Wisconsin, Madison, WI 53706, USA
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48
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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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49
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Kim Y, Heo IB, Yu JH, Shin KS. Characteristics of a Regulator of G-Protein Signaling (RGS) rgsC in Aspergillus fumigatus. Front Microbiol 2017; 8:2058. [PMID: 29109714 PMCID: PMC5660106 DOI: 10.3389/fmicb.2017.02058] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 10/06/2017] [Indexed: 12/12/2022] Open
Abstract
The regulator of G-protein signaling (RGS) proteins have a conserved RGS domain that facilitates the intrinsic GTPase activity of an activated Gα subunit of heterotrimeric G protein, thereby attenuating signal transduction. Among six predicted RGS proteins in the opportunistic human pathogenic fungus Aspergillus fumigatus, only three (FlbA, GprK, and Rax1) have been studied. The unexplored RgsC composed of the Phox-associated (PXA), RGS, Phox homology (PX), and Nexin_C superfamily domains is highly conserved in many ascomycete fungi, suggesting a crucial role of RgsC in fungal biology. To address this, we have investigated functions of the rgsC gene. The deletion (Δ) of rgsC causes impaired vegetative growth and asexual development coupled with reduced expression of key developmental regulators. Moreover, ΔrgsC results in accelerated and elevated conidial germination regardless of the presence or absence of an external carbon source. Furthermore, ΔrgsC causes reduced conidial tolerance to oxidative stress. In addition, activities and expression of catalases and superoxide dismutases (SODs) are severely decreased in the ΔrgsC mutant. The deletion of rgsC results in a slight reduction in conidial tolerance to cell wall damaging agents, yet significantly lowered mRNA levels of cell wall integrity/biogenesis transcription factors, indicating that RgsC may function in proper activation of cell wall stress response. The ΔrgsC mutant exhibits defective gliotoxin (GT) production and decreased virulence in the wax moth larvae, Galleria mellonella. Transcriptomic studies reveal that a majority of transporters is down-regulated by ΔrgsC and growth of the ΔrgsC mutant is reduced on inorganic and simple nitrogen medium, suggesting that RgsC may function in external nitrogen source sensing and/or transport. In summary, RgsC is necessary for proper growth, development, stress response, GT production, and external nutrients sensing.
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Affiliation(s)
- Young Kim
- Department of Biological Science, Daejeon University, Daejeon, South Korea
| | - In-Beom Heo
- Department of Biological Science, Daejeon University, Daejeon, South Korea
| | - Jae-Hyuk Yu
- Departments of Bacteriology and Genetics, University of Wisconsin-Madison, Madison, WI, United States
| | - Kwang-Soo Shin
- Department of Biological Science, Daejeon University, Daejeon, South Korea
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50
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Ergot alkaloids contribute to virulence in an insect model of invasive aspergillosis. Sci Rep 2017; 7:8930. [PMID: 28827626 PMCID: PMC5567044 DOI: 10.1038/s41598-017-09107-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 07/20/2017] [Indexed: 12/13/2022] Open
Abstract
Neosartorya fumigata (Aspergillus fumigatus) is the most common cause of invasive aspergillosis, a frequently fatal lung disease primarily affecting immunocompromised individuals. This opportunistic fungal pathogen produces several classes of specialised metabolites including products of a branch of the ergot alkaloid pathway called fumigaclavines. The biosynthesis of the N. fumigata ergot alkaloids and their relation to those produced by alternate pathway branches in fungi from the plant-inhabiting Clavicipitaceae have been well-characterised, but the potential role of these alkaloids in animal pathogenesis has not been studied extensively. We investigated the contribution of ergot alkaloids to virulence of N. fumigata by measuring mortality in the model insect Galleria mellonella. Larvae were injected with conidia (asexual spores) of two different wild-type strains of N. fumigata and three different ergot alkaloid mutants derived by previous gene knockouts and differing in ergot alkaloid profiles. Elimination of all ergot alkaloids significantly reduced virulence of N. fumigata in G. mellonella (P < 0.0001). Mutants accumulating intermediates but not the pathway end product fumigaclavine C also were less virulent than the wild type (P < 0.0003). The data indicate that ergot alkaloids contribute to virulence of N. fumigata in this insect model and that fumigaclavine C is important for full virulence.
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