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Yiu B, Robbins N, Cowen LE. Interdisciplinary approaches for the discovery of novel antifungals. Trends Mol Med 2024; 30:723-735. [PMID: 38777733 DOI: 10.1016/j.molmed.2024.04.018] [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: 02/16/2024] [Revised: 04/10/2024] [Accepted: 04/26/2024] [Indexed: 05/25/2024]
Abstract
Pathogenic fungi are an increasing public health concern. The emergence of antifungal resistance coupled with the scarce antifungal arsenal highlights the need for novel therapeutics. Fortunately, the past few years have witnessed breakthroughs in antifungal development. Here, we discuss pivotal interdisciplinary approaches for the discovery of novel compounds with efficacy against diverse fungal pathogens. We highlight breakthroughs in improving current antifungal scaffolds, as well as the utility of compound combinations to extend the lifespan of antifungals. Finally, we describe efforts to refine candidate chemical scaffolds by leveraging structure-guided approaches, and the use of functional genomics to expand our knowledge of druggable antifungal targets. Overall, we emphasize the importance of interdisciplinary collaborations in the endeavor to develop innovative antifungal strategies.
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Affiliation(s)
- Bonnie Yiu
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5G 1M1, Canada
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5G 1M1, Canada
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5G 1M1, Canada.
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2
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Cissé OH, Ma L, Kovacs JA. Retracing the evolution of Pneumocystis species, with a focus on the human pathogen Pneumocystis jirovecii. Microbiol Mol Biol Rev 2024; 88:e0020222. [PMID: 38587383 PMCID: PMC11332345 DOI: 10.1128/mmbr.00202-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/09/2024] Open
Abstract
SUMMARYEvery human being is presumed to be infected by the fungus Pneumocystis jirovecii at least once in his or her lifetime. This fungus belongs to a large group of species that appear to exclusively infect mammals, with P. jirovecii being the only one known to cause disease in humans. The mystery of P. jirovecii origin and speciation is just beginning to unravel. Here, we provide a review of the major steps of P. jirovecii evolution. The Pneumocystis genus likely originated from soil or plant-associated organisms during the period of Cretaceous ~165 million years ago and successfully shifted to mammals. The transition coincided with a substantial loss of genes, many of which are related to the synthesis of nutrients that can be scavenged from hosts or cell wall components that could be targeted by the mammalian immune system. Following the transition, the Pneumocystis genus cospeciated with mammals. Each species specialized at infecting its own host. Host specialization is presumably built at least partially upon surface glycoproteins, whose protogene was acquired prior to the genus formation. P. jirovecii appeared at ~65 million years ago, overlapping with the emergence of the first primates. P. jirovecii and its sister species P. macacae, which infects macaques nowadays, may have had overlapping host ranges in the distant past. Clues from molecular clocks suggest that P. jirovecii did not cospeciate with humans. Molecular evidence suggests that Pneumocystis speciation involved chromosomal rearrangements and the mounting of genetic barriers that inhibit gene flow among species.
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Affiliation(s)
- Ousmane H. Cissé
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Liang Ma
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Joseph A. Kovacs
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
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3
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Feng Z, Lu H, Jiang Y. Promising immunotherapeutic targets for treating candidiasis. Front Cell Infect Microbiol 2024; 14:1339501. [PMID: 38404288 PMCID: PMC10884116 DOI: 10.3389/fcimb.2024.1339501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 01/29/2024] [Indexed: 02/27/2024] Open
Abstract
In the last twenty years, there has been a significant increase in invasive fungal infections, which has corresponded with the expanding population of individuals with compromised immune systems. As a result, the mortality rate linked to these infections remains unacceptably high. The currently available antifungal drugs, such as azoles, polyenes, and echinocandins, face limitations in terms of their diversity, the escalating resistance of fungi and the occurrence of significant adverse effects. Consequently, there is an urgent need to develop new antifungal medications. Vaccines and antibodies present a promising avenue for addressing fungal infections due to their targeted antifungal properties and ability to modulate the immune response. This review investigates the structure and function of cell wall proteins, secreted proteins, and functional proteins within C. albicans. Furthermore, it seeks to analyze the current advancements and challenges in macromolecular drugs to identify new targets for the effective management of candidiasis.
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Affiliation(s)
| | - Hui Lu
- Department of Pharmacy, Shanghai Tenth People’s Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Yuanying Jiang
- Department of Pharmacy, Shanghai Tenth People’s Hospital, School of Medicine, Tongji University, Shanghai, China
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4
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Vanzolini T, Magnani M. Old and new strategies in therapy and diagnosis against fungal infections. Appl Microbiol Biotechnol 2024; 108:147. [PMID: 38240822 PMCID: PMC10799149 DOI: 10.1007/s00253-023-12884-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 12/05/2023] [Accepted: 12/05/2023] [Indexed: 01/22/2024]
Abstract
Fungal infections represent a serious global health threat. The new emerging pathogens and the spread of different forms of resistance are now hardly challenging the tools available in therapy and diagnostics. With the commonly used diagnoses, fungal identification is often slow and inaccurate, and, on the other hand, some drugs currently used as treatments are significantly affected by the decrease in susceptibility. Herein, the antifungal arsenal is critically summarized. Besides describing the old approaches and their mechanisms, advantages, and limitations, the focus is dedicated to innovative strategies which are designed, identified, and developed to take advantage of the discrepancies between fungal and host cells. Relevant pathways and their role in survival and virulence are discussed as their suitability as sources of antifungal targets. In a similar way, molecules with antifungal activity are reported as potential agents/precursors of the next generation of antimycotics. Particular attention was devoted to biotechnological entities, to their novelty and reliability, to drug repurposing and restoration, and to combinatorial applications yielding significant improvements in efficacy. KEY POINTS: • New antifungal agents and targets are needed to limit fungal morbidity and mortality. • Therapeutics and diagnostics suffer of delays in innovation and lack of targets. • Biologics, drug repurposing and combinations are the future of antifungal treatments.
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Affiliation(s)
- Tania Vanzolini
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, 61029, Urbino, PU, Italy.
| | - Mauro Magnani
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, 61029, Urbino, PU, Italy
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5
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Kaur A, Sharma K, Sharma N, Aggarwal G. An Insight into the Repurposing of Phytoconstituents obtained from Delhi's Aravalli Biodiversity Park as Antifungal Agents. Infect Disord Drug Targets 2024; 24:e020224226666. [PMID: 38305295 DOI: 10.2174/0118715265282411240119061441] [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: 09/15/2023] [Revised: 12/04/2023] [Accepted: 12/11/2023] [Indexed: 02/03/2024]
Abstract
The global prevalence of fungal infections is alarming in both the pre- and post- COVID period. Due to a limited number of antifungal drugs, there are hurdles in treatment strategies for fungal infections due to toxic potential, drug interactions, and the development of fungal resistance. All the antifungal targets (existing and newer) and pipeline molecules showing promise against these targets are reviewed. The objective was to predict or repurpose phyto-based antifungal compounds based on a dual target inhibition approach (Sterol-14-α- demethylase and HSP-90) using a case study. In pursuit of repurposing the phytochemicals as antifungal agents, a team of researchers visited Aravalli Biodiversity Park (ABP), Delhi, India, to collect information on available medicinal plants. From 45 plants, a total of 1149 ligands were collected, and virtual screening was performed using Schrodinger Suite 2016 software to get 83 hits against both the target proteins: Sterol-14-α-demethylase and HSP-90. After analysis of docking results, ligands were selected based on their interaction against both the target proteins and comparison with respective standard ligands (fluconazole and ganetespib). We have selected Isocarthamidin, Quercetin and Boeravinone B based on their docking score and binding interaction against the HSP-90 (Docking Score -9.65, -9.22 and -9.21, respectively) and 14-α-demethylase (Docking Score -9.19, -10.76 and -9.74 respectively). The docking protocol was validated and MM/GBSA studies depicted better stability of selected three ligands (Isocarthamidin, Quercetin, Boeravinone B) complex as compared to standard complex. Further, MD simulation studies were performed using the Desmond (67) software package version 2018-4. All the findings are presented as a case study for the prediction of dual targets for the repurposing of certain phytochemicals as antifungal agents.
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Affiliation(s)
- Amanpreet Kaur
- Delhi Pharmaceutical Sciences and Research University, M.B. Road, Sector III, Pushp Vihar, New Delhi, 110017, India
| | - Kalicharan Sharma
- Delhi Pharmaceutical Sciences and Research University, M.B. Road, Sector III, Pushp Vihar, New Delhi, 110017, India
| | - Neetika Sharma
- Delhi Pharmaceutical Sciences and Research University, M.B. Road, Sector III, Pushp Vihar, New Delhi, 110017, India
| | - Geeta Aggarwal
- Delhi Pharmaceutical Sciences and Research University, M.B. Road, Sector III, Pushp Vihar, New Delhi, 110017, India
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6
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Robbins N, Cowen LE. Roles of Hsp90 in Candida albicans morphogenesis and virulence. Curr Opin Microbiol 2023; 75:102351. [PMID: 37399670 PMCID: PMC11016340 DOI: 10.1016/j.mib.2023.102351] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 06/02/2023] [Accepted: 06/04/2023] [Indexed: 07/05/2023]
Abstract
Hsp90 is a conserved molecular chaperone that facilitates the folding and function of hundreds of client proteins, many of which serve as core hubs of signal transduction networks. Hsp90 has a critical role in virulence of the opportunistic fungal pathogen Candida albicans, which exists as a natural commensal of the human microbiota and is a leading cause of invasive fungal infections, particularly in immunocompromised individuals. The ability of C. albicans to cause disease is tightly coupled to its capacity to undergo a morphogenetic transition between yeast and filamentous forms. Here, we describe the complex mechanisms by which Hsp90 regulates C. albicans morphogenesis and virulence, and explore the potential of targeting fungal Hsp90 as a therapeutic strategy to combat fungal infections.
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Affiliation(s)
- Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada.
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7
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Neves-da-Rocha J, Santos-Saboya MJ, Lopes MER, Rossi A, Martinez-Rossi NM. Insights and Perspectives on the Role of Proteostasis and Heat Shock Proteins in Fungal Infections. Microorganisms 2023; 11:1878. [PMID: 37630438 PMCID: PMC10456932 DOI: 10.3390/microorganisms11081878] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 06/30/2023] [Accepted: 07/06/2023] [Indexed: 08/27/2023] Open
Abstract
Fungi are a diverse group of eukaryotic organisms that infect humans, animals, and plants. To successfully colonize their hosts, pathogenic fungi must continuously adapt to the host's unique environment, e.g., changes in temperature, pH, and nutrient availability. Appropriate protein folding, assembly, and degradation are essential for maintaining cellular homeostasis and survival under stressful conditions. Therefore, the regulation of proteostasis is crucial for fungal pathogenesis. The heat shock response (HSR) is one of the most important cellular mechanisms for maintaining proteostasis. It is activated by various stresses and regulates the activity of heat shock proteins (HSPs). As molecular chaperones, HSPs participate in the proteostatic network to control cellular protein levels by affecting their conformation, location, and degradation. In recent years, a growing body of evidence has highlighted the crucial yet understudied role of stress response circuits in fungal infections. This review explores the role of protein homeostasis and HSPs in fungal pathogenicity, including their contributions to virulence and host-pathogen interactions, as well as the concerted effects between HSPs and the main proteostasis circuits in the cell. Furthermore, we discuss perspectives in the field and the potential for targeting the components of these circuits to develop novel antifungal therapies.
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Affiliation(s)
- João Neves-da-Rocha
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14049-900, SP, Brazil; (M.J.S.-S.); (M.E.R.L.); (A.R.)
| | | | | | | | - Nilce M. Martinez-Rossi
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14049-900, SP, Brazil; (M.J.S.-S.); (M.E.R.L.); (A.R.)
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8
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Dos Reis TF, de Castro PA, Bastos RW, Pinzan CF, Souza PFN, Ackloo S, Hossain MA, Drewry DH, Alkhazraji S, Ibrahim AS, Jo H, Lightfoot JD, Adams EM, Fuller KK, deGrado WF, Goldman GH. A host defense peptide mimetic, brilacidin, potentiates caspofungin antifungal activity against human pathogenic fungi. Nat Commun 2023; 14:2052. [PMID: 37045836 PMCID: PMC10090755 DOI: 10.1038/s41467-023-37573-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 03/23/2023] [Indexed: 04/14/2023] Open
Abstract
Fungal infections cause more than 1.5 million deaths a year. Due to emerging antifungal drug resistance, novel strategies are urgently needed to combat life-threatening fungal diseases. Here, we identify the host defense peptide mimetic, brilacidin (BRI) as a synergizer with caspofungin (CAS) against CAS-sensitive and CAS-resistant isolates of Aspergillus fumigatus, Candida albicans, C. auris, and CAS-intrinsically resistant Cryptococcus neoformans. BRI also potentiates azoles against A. fumigatus and several Mucorales fungi. BRI acts in A. fumigatus by affecting cell wall integrity pathway and cell membrane potential. BRI combined with CAS significantly clears A. fumigatus lung infection in an immunosuppressed murine model of invasive pulmonary aspergillosis. BRI alone also decreases A. fumigatus fungal burden and ablates disease development in a murine model of fungal keratitis. Our results indicate that combinations of BRI and antifungal drugs in clinical use are likely to improve the treatment outcome of aspergillosis and other fungal infections.
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Affiliation(s)
- Thaila Fernanda Dos Reis
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Patrícia Alves de Castro
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Rafael Wesley Bastos
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Camila Figueiredo Pinzan
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Pedro F N Souza
- Visiting professor at Drug Research and Development Center, Department of Physiology and Pharmacology, Federal University of Ceará, Fortaleza, Ceará, 60451, Brazil
| | - Suzanne Ackloo
- Structural Genomics Consortium, University of Toronto, 101 College Street, MaRS South Tower, Suite 700, Toronto, ON, M5G 1L7, Canada
| | - Mohammad Anwar Hossain
- Structural Genomics Consortium, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - David Harold Drewry
- Structural Genomics Consortium, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
- Lineberger Comprehensive Cancer Center, Department of Medicine, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Sondus Alkhazraji
- Division of Infectious Diseases, The Lundquist Institute for Biomedical Innovation at Harbor-University of California Los Angeles (UCLA) Medical Center, Torrance, CA, 90502, USA
| | - Ashraf S Ibrahim
- Division of Infectious Diseases, The Lundquist Institute for Biomedical Innovation at Harbor-University of California Los Angeles (UCLA) Medical Center, Torrance, CA, 90502, USA
- David Geffen School of Medicine at UCLA, Los Angeles, CA, 90095, USA
| | - Hyunil Jo
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, 94143, USA
| | - Jorge D Lightfoot
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Emily M Adams
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Kevin K Fuller
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - William F deGrado
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, 94143, USA
| | - Gustavo H Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil.
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9
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Soil-Borne Neosartorya spp.: A Heat-Resistant Fungal Threat to Horticulture and Food Production-An Important Component of the Root-Associated Microbial Community. Int J Mol Sci 2023; 24:ijms24021543. [PMID: 36675060 PMCID: PMC9867472 DOI: 10.3390/ijms24021543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 01/10/2023] [Accepted: 01/11/2023] [Indexed: 01/15/2023] Open
Abstract
Soil-borne Neosartorya spp. are the highly resilient sexual reproductive stage (teleomorph) of Aspergillus spp. Fungi of this genus are relevant components of root-associated microbial community, but they can also excrete mycotoxins and exhibit great resistance to high temperatures. Their ascospores easily transfer between soil and crops; thus, Neosartorya poses a danger to horticulture and food production, especially to the postharvest quality of fruits and vegetables. The spores are known to cause spoilage, mainly in raw fruit produce, juices, and pulps, despite undergoing pasteurization. However, these fungi can also participate in carbon transformation and sequestration, as well as plant protection in drought conditions. Many species have been identified and included in the genus, and yet some of them create taxonomical controversy due to their high similarity. This also contributes to Neosartorya spp. being easily mistaken for its anamorph, resulting in uncertain data within many studies. The review discusses also the factors shaping Neosartorya spp.'s resistance to temperature, preservatives, chemicals, and natural plant extracts, as well as presenting novel solutions to problems created by its resilient nature.
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10
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Ancuceanu R, Hovaneț MV, Cojocaru-Toma M, Anghel AI, Dinu M. Potential Antifungal Targets for Aspergillus sp. from the Calcineurin and Heat Shock Protein Pathways. Int J Mol Sci 2022; 23:ijms232012543. [PMID: 36293395 PMCID: PMC9603945 DOI: 10.3390/ijms232012543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 10/13/2022] [Accepted: 10/15/2022] [Indexed: 11/16/2022] Open
Abstract
Aspergillus species, especially A. fumigatus, and to a lesser extent others (A. flavus, A. niger, A. terreus), although rarely pathogenic to healthy humans, can be very aggressive to immunocompromised patients (they are opportunistic pathogens). Although survival rates for such infections have improved in recent decades following the introduction of azole derivatives, they remain a clinical challenge. The fact that current antifungals act as fungistatic rather than fungicide, that they have limited safety, and that resistance is becoming increasingly common make the need for new, more effective, and safer therapies to become more acute. Over the last decades, knowledge about the molecular biology of A. fumigatus and other Aspergillus species, and particularly of calcineurin, Hsp90, and their signaling pathway proteins, has progressed remarkably. Although calcineurin has attracted much interest, its adverse effects, particularly its immunosuppressive effects, make it less attractive than it might at first appear. The situation is not very different for Hsp90. Other proteins from their signaling pathways, such as protein kinases phosphorylating the four SPRR serine residues, CrzA, rcnA, pmcA-pmcC (particularly pmcC), rfeF, BAR adapter protein(s), the phkB histidine kinase, sskB MAP kinase kinase, zfpA, htfA, ctfA, SwoH (nucleoside diphosphate kinase), CchA, MidA, FKBP12, the K27 lysine position from Hsp90, PkcA, MpkA, RlmA, brlA, abaA, wetA, other heat shock proteins (Hsp70, Hsp40, Hsp12) currently appear promising and deserve further investigation as potential targets for antifungal drug development.
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Affiliation(s)
- Robert Ancuceanu
- Faculty of Pharmacy, Carol Davila University of Medicine and Pharmacy, 020956 Bucharest, Romania
- Correspondence: (R.A.); (M.V.H.)
| | - Marilena Viorica Hovaneț
- Faculty of Pharmacy, Carol Davila University of Medicine and Pharmacy, 020956 Bucharest, Romania
- Correspondence: (R.A.); (M.V.H.)
| | - Maria Cojocaru-Toma
- Faculty of Pharmacy, Nicolae Testemițanu State University of Medicine and Pharmacy, 2025 Chisinau, Moldova
| | - Adriana-Iuliana Anghel
- Faculty of Pharmacy, Carol Davila University of Medicine and Pharmacy, 020956 Bucharest, Romania
| | - Mihaela Dinu
- Faculty of Pharmacy, Carol Davila University of Medicine and Pharmacy, 020956 Bucharest, Romania
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11
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Regulation of Hsp80 involved in the acquisition of induced thermotolerance, and NCA-2 involved in calcium stress tolerance by the calcineurin-CRZ-1 signaling pathway in Neurospora crassa. Mycol Prog 2022. [DOI: 10.1007/s11557-022-01833-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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12
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Robbins N, Cowen LE. Genomic Approaches to Antifungal Drug Target Identification and Validation. Annu Rev Microbiol 2022; 76:369-388. [PMID: 35650665 PMCID: PMC10727914 DOI: 10.1146/annurev-micro-041020-094524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The last several decades have witnessed a surge in drug-resistant fungal infections that pose a serious threat to human health. While there is a limited arsenal of drugs that can be used to treat systemic infections, scientific advances have provided renewed optimism for the discovery of novel antifungals. The development of chemical-genomic assays using Saccharomyces cerevisiae has provided powerful methods to identify the mechanism of action of molecules in a living cell. Advances in molecular biology techniques have enabled complementary assays to be developed in fungal pathogens, including Candida albicans and Cryptococcus neoformans. These approaches enable the identification of target genes for drug candidates, as well as genes involved in buffering drug target pathways. Here, we examine yeast chemical-genomic assays and highlight how such resources can be utilized to predict the mechanisms of action of compounds, to study virulence attributes of diverse fungal pathogens, and to bolster the antifungal pipeline.
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Affiliation(s)
- Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada;
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada;
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13
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Verburg K, van Neer J, Duca M, de Cock H. Novel Treatment Approach for Aspergilloses by Targeting Germination. J Fungi (Basel) 2022; 8:758. [PMID: 35893126 PMCID: PMC9331470 DOI: 10.3390/jof8080758] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 07/03/2022] [Accepted: 07/19/2022] [Indexed: 12/24/2022] Open
Abstract
Germination of conidia is an essential process within the Aspergillus life cycle and plays a major role during the infection of hosts. Conidia are able to avoid detection by the majority of leukocytes when dormant. Germination can cause severe health problems, specifically in immunocompromised people. Aspergillosis is most often caused by Aspergillus fumigatus (A. fumigatus) and affects neutropenic patients, as well as people with cystic fibrosis (CF). These patients are often unable to effectively detect and clear the conidia or hyphae and can develop chronic non-invasive and/or invasive infections or allergic inflammatory responses. Current treatments with (tri)azoles can be very effective to combat a variety of fungal infections. However, resistance against current azoles has emerged and has been increasing since 1998. As a consequence, patients infected with resistant A. fumigatus have a reported mortality rate of 88% to 100%. Especially with the growing number of patients that harbor azole-resistant Aspergilli, novel antifungals could provide an alternative. Aspergilloses differ in defining characteristics, but germination of conidia is one of the few common denominators. By specifically targeting conidial germination with novel antifungals, early intervention might be possible. In this review, we propose several morphotypes to disrupt conidial germination, as well as potential targets. Hopefully, new antifungals against such targets could contribute to disturbing the ability of Aspergilli to germinate and grow, resulting in a decreased fungal burden on patients.
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Affiliation(s)
- Kim Verburg
- Molecular Microbiology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands; (K.V.); (J.v.N.)
| | - Jacq van Neer
- Molecular Microbiology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands; (K.V.); (J.v.N.)
| | - Margherita Duca
- Department of Chemical Biology & Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CG Utrecht, The Netherlands;
| | - Hans de Cock
- Molecular Microbiology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands; (K.V.); (J.v.N.)
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14
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Liu L, Zhang X, Kayastha S, Tan L, Zhang H, Tan J, Li L, Mao J, Sun Y. A Preliminary in vitro and in vivo Evaluation of the Effect and Action Mechanism of 17-AAG Combined With Azoles Against Azole-Resistant Candida spp. Front Microbiol 2022; 13:825745. [PMID: 35875545 PMCID: PMC9300965 DOI: 10.3389/fmicb.2022.825745] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 06/20/2022] [Indexed: 01/09/2023] Open
Abstract
Invasive candidiasis is the primary reason for the increased cases of mortality in a medical environment. The resistance spectra of Candida species to antifungal drugs have gradually expanded. Particularly, the resistance spectra of Candida auris are the most prominent. Hsp90 plays a protective role in the stress response of fungi and facilitates their virulence. In contrast, Hsp90 inhibitors can improve the resistance of fungi to antifungal drugs by regulating the heat resistance of Hsp90, which destroys the integrity of the fungal cell walls. Hsp90 inhibitors thus offer a great potential to reduce or address fungal drug resistance. The drugs tested for the resistance include itraconazole, voriconazole, posaconazole, fluconazole, and 17-AAG. A total of 20 clinical strains of Candida were investigated. The broth microdilution checkerboard technique, as adapted from the CLSI M27-A4 method, was applied in this study. We found that 17-AAG alone exerted limited antifungal activity against all tested strains. The MIC range of 17-AAG was 8 to >32 μg/ml. A synergy was observed among 17-AAG and itraconazole, voriconazole, and posaconazole against 10 (50%), 7 (35%), and 13 (65%) of all isolates, respectively. Moreover, the synergy between 17-AAG and fluconazole was observed against 5 (50%) strains of azole-resistant Candida. However, no antagonism was recorded overall. Our result adequately verifies the influence of 17-AAG on the formation of Candida spp. biofilm. Moreover, we determined that with the use of rhodamine 6G to detect drug efflux and that of dihydrorhodamine-123 to detect intracellular reactive oxygen species (ROS), treatment with 17-AAG combined with azole drugs could inhibit the efflux pump of fungi and promote the accumulation of ROS in the fungal cells, thereby inducing fungal cell apoptosis. Thus, the mechanism of 17-AAG combined with azoles can kill fungi. Our results thus provide a new idea to further explore drugs against drug-resistant Candida spp.
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Affiliation(s)
| | | | | | | | | | - Jingwen Tan
- Department of Medical Mycology, Shanghai Skin Disease Hospital, Tongji University School of Medicine, Shanghai, China
| | - Linyun Li
- Clinical Lab, Jingzhou Hospital, Yangtze University, Jingzhou, China
| | - Jinghua Mao
- Department of Cardiology, Jingzhou Hospital, Yangtze University, Jingzhou, China
- *Correspondence: Jinghua Mao,
| | - Yi Sun
- Department of Dermatology, Jingzhou Hospital, Yangtze University, Candidate Branch of National Clinical Research Center for Skin and Immune Diseases, Jingzhou, China
- Yi Sun,
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15
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Zhen C, Lu H, Jiang Y. Novel Promising Antifungal Target Proteins for Conquering Invasive Fungal Infections. Front Microbiol 2022; 13:911322. [PMID: 35783432 PMCID: PMC9243655 DOI: 10.3389/fmicb.2022.911322] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Accepted: 05/24/2022] [Indexed: 11/26/2022] Open
Abstract
Invasive fungal infections (IFIs) pose a serious clinical problem, but the antifungal arsenal is limited and has many disadvantages, such as drug resistance and toxicity. Hence, there is an urgent need to develop antifungal compounds that target novel target proteins of pathogenic fungi for treating IFIs. This review provides a comprehensive summary of the biological functions of novel promising target proteins for treating IFIs in pathogenic fungi and their inhibitors. Inhibitors of inositol phosphoramide (IPC) synthases (such as Aureobasidin A, Khafrefungin, Galbonolide A, and Pleofungin A) have potent antifungal activities by inhibiting sphingolipid synthesis. Disrupting glycosylphosphatidylinositol (GPI) biosynthesis by Jawsamycin (an inhibitor of Spt14), M720 (an inhibitor of Mcd4), and APX001A (an inhibitor of Gwt1) is a promising strategy for treating IFIs. Turbinmicin is a natural-compound inhibitor of Sec14 and has extraordinary antifungal efficacy, broad-antifungal spectrum, low toxicity, and is a promising new compound for treating IFIs. CMLD013075 targets fungal heat shock protein 90 (Hsp90) and has remarkable antifungal efficacy. Olorofim, as an inhibitor of dihydrolactate dehydrogenase, is a breakthrough drug treatment for IFIs. These novel target proteins and their inhibitors may overcome the limitations of currently available antifungal drugs and improve patient outcomes in the treatment of IFIs.
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16
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Heat shock proteins and the calcineurin-crz1 signaling regulate stress responses in fungi. Arch Microbiol 2022; 204:240. [PMID: 35377020 DOI: 10.1007/s00203-022-02833-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 03/07/2022] [Accepted: 03/09/2022] [Indexed: 12/26/2022]
Abstract
The heat shock proteins (Hsps) act as a molecular chaperone to stabilize client proteins involved in various cell functions in fungi. Hsps are classified into different families such as HSP90, HSP70, HSP60, HSP40, and small HSPs (sHsps). Hsp90, a well-studied member of the Hsp family proteins, plays a role in growth, cell survival, and pathogenicity in fungi. Hsp70 and sHsps are involved in the development, tolerance to stress conditions, and drug resistance in fungi. Hsp60 is a mitochondrial chaperone, and Hsp40 regulates fungal ATPase machinery. In this review, we describe the cell functions, regulation, and the molecular link of the Hsps with the calcineurin-crz1 calcium signaling pathway for their role in cell survival, growth, virulence, and drug resistance in fungi and related organisms.
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17
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Gao X, Wang Q, Feng Q, Zhang B, He C, Luo H, An B. Heat Shock Transcription Factor CgHSF1 Is Required for Melanin Biosynthesis, Appressorium Formation, and Pathogenicity in Colletotrichum gloeosporioides. J Fungi (Basel) 2022; 8:jof8020175. [PMID: 35205929 PMCID: PMC8876323 DOI: 10.3390/jof8020175] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 02/06/2022] [Accepted: 02/07/2022] [Indexed: 01/09/2023] Open
Abstract
Heat shock transcription factors (HSFs) are a family of transcription regulators. Although HSFs’ functions in controlling the transcription of the molecular chaperone heat shock proteins and resistance to stresses are well established, their effects on the pathogenicity of plant pathogenic fungi remain unknown. In this study, we analyze the role of CgHSF1 in the pathogenicity of Colletotrichum gloeosporioides and investigate the underlying mechanism. Failure to generate the Cghsf1 knock-out mutant suggested that the gene is essential for the viability of the fungus. Then, genetic depletion of the Cghsf1 was achieved by inserting the repressive promoter of nitrite reductase gene (PniiA) before its coding sequence. The mutant showed significantly decrease in the pathogenicity repression of appressorium formation, and severe defects in melanin biosynthesis. Moreover, four melanin synthetic genes were identified as direct targets of CgHSF1. Taken together, this work highlights the role of CgHSF1 in fungal pathogenicity via the transcriptional activation of melanin biosynthesis. Our study extends the understanding of fungal HSF1 proteins, especially their involvement in pathogenicity.
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Affiliation(s)
- Xuesheng Gao
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, College of Tropical Crops, Hainan University, Haikou 570228, China; (X.G.); (Q.W.); (Q.F.); (B.Z.); (C.H.)
- Sanya Nanfan Research Institute, Hainan University, Sanya 572025, China
| | - Qiannan Wang
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, College of Tropical Crops, Hainan University, Haikou 570228, China; (X.G.); (Q.W.); (Q.F.); (B.Z.); (C.H.)
- Sanya Nanfan Research Institute, Hainan University, Sanya 572025, China
| | - Qingdeng Feng
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, College of Tropical Crops, Hainan University, Haikou 570228, China; (X.G.); (Q.W.); (Q.F.); (B.Z.); (C.H.)
| | - Bei Zhang
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, College of Tropical Crops, Hainan University, Haikou 570228, China; (X.G.); (Q.W.); (Q.F.); (B.Z.); (C.H.)
- Sanya Nanfan Research Institute, Hainan University, Sanya 572025, China
| | - Chaozu He
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, College of Tropical Crops, Hainan University, Haikou 570228, China; (X.G.); (Q.W.); (Q.F.); (B.Z.); (C.H.)
- Sanya Nanfan Research Institute, Hainan University, Sanya 572025, China
| | - Hongli Luo
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, College of Tropical Crops, Hainan University, Haikou 570228, China; (X.G.); (Q.W.); (Q.F.); (B.Z.); (C.H.)
- Sanya Nanfan Research Institute, Hainan University, Sanya 572025, China
- Correspondence: (H.L.); (B.A.)
| | - Bang An
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, College of Tropical Crops, Hainan University, Haikou 570228, China; (X.G.); (Q.W.); (Q.F.); (B.Z.); (C.H.)
- Sanya Nanfan Research Institute, Hainan University, Sanya 572025, China
- Correspondence: (H.L.); (B.A.)
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18
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Sharma A, Alajangi HK, Pisignano G, Sood V, Singh G, Barnwal RP. RNA thermometers and other regulatory elements: Diversity and importance in bacterial pathogenesis. WILEY INTERDISCIPLINARY REVIEWS. RNA 2022; 13:e1711. [PMID: 35037405 DOI: 10.1002/wrna.1711] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Revised: 11/09/2021] [Accepted: 12/16/2021] [Indexed: 01/11/2023]
Abstract
Survival of microorganisms depends to a large extent on environmental conditions and the occupied host. By adopting specific strategies, microorganisms can thrive in the surrounding environment and, at the same time, preserve their viability. Evading the host defenses requires several mechanisms compatible with the host survival which include the production of RNA thermometers to regulate the expression of genes responsible for heat or cold shock as well as of those involved in virulence. Microorganisms have developed a variety of molecules in response to the environmental changes in temperature and even more specifically to the host they invade. Among all, RNA-based regulatory mechanisms are the most common ones, highlighting the importance of such molecules in gene expression control and novel drug development by suitable structure-based alterations. This article is categorized under: RNA Structure and Dynamics > RNA Structure, Dynamics and Chemistry RNA in Disease and Development > RNA in Disease RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems.
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Affiliation(s)
- Akanksha Sharma
- Department of Biophysics, Panjab University, Chandigarh, India.,University Institute of Pharmaceutical Sciences, Panjab University, Chandigarh, India
| | - Hema Kumari Alajangi
- Department of Biophysics, Panjab University, Chandigarh, India.,University Institute of Pharmaceutical Sciences, Panjab University, Chandigarh, India
| | | | - Vikas Sood
- Department of Biochemistry, Jamia Hamdard, New Delhi, India
| | - Gurpal Singh
- University Institute of Pharmaceutical Sciences, Panjab University, Chandigarh, India
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19
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Tr-milRNA1 Contributes to Lignocellulase Secretion under Heat Stress by Regulating the Lectin-Type Cargo Receptor Gene Trvip36 in Trichoderma guizhouence NJAU 4742. J Fungi (Basel) 2021; 7:jof7120997. [PMID: 34946980 PMCID: PMC8704016 DOI: 10.3390/jof7120997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 11/19/2021] [Accepted: 11/20/2021] [Indexed: 11/23/2022] Open
Abstract
Background: MicroRNA plays an important role in multifarious biological processes by regulating their corresponding target genes. However, the biological function and regulatory mechanism of fungal microRNA-like RNAs (milRNAs) remain poorly understood. Methods: In this study, combined with deep sequencing and bioinformatics analysis, milRNAs and their targets from Trichoderma guizhouence NJAU 4742 were isolated and identified under solid-state fermentation (SSF) by using rice straw as the sole carbon source at 28 °C and 37 °C, respectively. Results: A critical milRNA, TGA1_S04_31828 (Tr-milRNA1), was highly expressed under heat stress (37 °C) and adaptively regulated lignocellulase secretion. Overexpression of Tr-milRNA1 (OE-Tr-milRNA1) did not affect vegetative growth, but significantly increased lignocellulose utilization under heat stress. Based on the bioinformatics analysis and qPCR validation, a target of Tr-milRNA1 was identified as Trvip36, a lectin-type cargo receptor. The expression of Tr-milRNA1 and Trvip36 showed a divergent trend under SSF when the temperature was increased from 28 °C to 37 °C. In addition, the expression of Trvip36 was suppressed significantly in Tr-milRNA1 overexpression strain (OE-Tr-milRNA1). Compared with the wild type, deletion of Trvip36 (ΔTrvip36) significantly improved the secretion of lignocellulases by reducing the retention of lignocellulases in the ER under heat stress. Conclusions: Tr-milRNA1 from NJAU 4742 improved lignocellulose utilization under heat stress by regulating the expression of the corresponding target gene Trvip36. These findings might open avenues for exploring the mechanism of lignocellulase secretion in filamentous fungi.
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20
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Alaalm L, Crunden JL, Butcher M, Obst U, Whealy R, Williamson CE, O'Brien HE, Schaffitzel C, Ramage G, Spencer J, Diezmann S. Identification and Phenotypic Characterization of Hsp90 Phosphorylation Sites That Modulate Virulence Traits in the Major Human Fungal Pathogen Candida albicans. Front Cell Infect Microbiol 2021; 11:637836. [PMID: 34513723 PMCID: PMC8431828 DOI: 10.3389/fcimb.2021.637836] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 05/24/2021] [Indexed: 01/13/2023] Open
Abstract
The highly conserved, ubiquitous molecular chaperone Hsp90 is a key regulator of cellular proteostasis and environmental stress responses. In human pathogenic fungi, which kill more than 1.6 million patients each year worldwide, Hsp90 governs cellular morphogenesis, drug resistance, and virulence. Yet, our understanding of the regulatory mechanisms governing fungal Hsp90 function remains sparse. Post-translational modifications are powerful components of nature’s toolbox to regulate protein abundance and function. Phosphorylation in particular is critical in many cellular signaling pathways and errant phosphorylation can have dire consequences for the cell. In the case of Hsp90, phosphorylation affects its stability and governs its interactions with co-chaperones and clients. Thereby modulating the cell’s ability to cope with environmental stress. Candida albicans, one of the leading human fungal pathogens, causes ~750,000 life-threatening invasive infections worldwide with unacceptably high mortality rates. Yet, it remains unknown if and how Hsp90 phosphorylation affects C. albicans virulence traits. Here, we show that phosphorylation of Hsp90 is critical for expression of virulence traits. We combined proteomics, molecular evolution analyses and structural modeling with molecular biology to characterize the role of Hsp90 phosphorylation in this non-model pathogen. We demonstrated that phosphorylation negatively affects key virulence traits, such as the thermal stress response, morphogenesis, and drug susceptibility. Our results provide the first record of a specific Hsp90 phosphorylation site acting as modulator of fungal virulence. Post-translational modifications of Hsp90 could prove valuable in future exploitations as antifungal drug targets.
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Affiliation(s)
- Leenah Alaalm
- Department of Biology & Biochemistry, University of Bath, Bath, United Kingdom
| | - Julia L Crunden
- Department of Biology & Biochemistry, University of Bath, Bath, United Kingdom.,School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Mark Butcher
- School of Medicine, Dentistry and Nursing, University of Glasgow, Glasgow, United Kingdom
| | - Ulrike Obst
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Ryann Whealy
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | | | - Heath E O'Brien
- MRC Centre for Neuropsychiatric Genetics & Genomics, Division of Psychological Medicine & Clinical Neurosciences, Cardiff University, Cardiff, United Kingdom
| | | | - Gordon Ramage
- School of Medicine, Dentistry and Nursing, University of Glasgow, Glasgow, United Kingdom
| | - James Spencer
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Stephanie Diezmann
- Department of Biology & Biochemistry, University of Bath, Bath, United Kingdom.,School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
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21
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Fabri JHTM, Rocha MC, Fernandes CM, Persinoti GF, Ries LNA, da Cunha AF, Goldman GH, Del Poeta M, Malavazi I. The Heat Shock Transcription Factor HsfA Is Essential for Thermotolerance and Regulates Cell Wall Integrity in Aspergillus fumigatus. Front Microbiol 2021; 12:656548. [PMID: 33897671 PMCID: PMC8062887 DOI: 10.3389/fmicb.2021.656548] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 03/11/2021] [Indexed: 12/13/2022] Open
Abstract
The deleterious effects of human-induced climate change have long been predicted. However, the imminent emergence and spread of new diseases, including fungal infections through the rise of thermotolerant strains, is still neglected, despite being a potential consequence of global warming. Thermotolerance is a remarkable virulence attribute of the mold Aspergillus fumigatus. Under high-temperature stress, opportunistic fungal pathogens deploy an adaptive mechanism known as heat shock (HS) response controlled by heat shock transcription factors (HSFs). In eukaryotes, HSFs regulate the expression of several heat shock proteins (HSPs), such as the chaperone Hsp90, which is part of the cellular program for heat adaptation and a direct target of HSFs. We recently observed that the perturbation in cell wall integrity (CWI) causes concomitant susceptibility to elevated temperatures in A. fumigatus, although the mechanisms underpinning the HS response and CWI cross talking are not elucidated. Here, we aim at further deciphering the interplay between HS and CWI. Our results show that cell wall ultrastructure is severely modified when A. fumigatus is exposed to HS. We identify the transcription factor HsfA as essential for A. fumigatus viability, thermotolerance, and CWI. Indeed, HS and cell wall stress trigger the coordinated expression of both hsfA and hsp90. Furthermore, the CWI signaling pathway components PkcA and MpkA were shown to be important for HsfA and Hsp90 expression in the A. fumigatus biofilms. Lastly, RNA-sequencing confirmed that hsfA regulates the expression of genes related to the HS response, cell wall biosynthesis and remodeling, and lipid homeostasis. Our studies collectively demonstrate the connection between the HS and the CWI pathway, with HsfA playing a crucial role in this cross-pathway regulation, reinforcing the importance of the cell wall in A. fumigatus thermophily.
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Affiliation(s)
| | - Marina Campos Rocha
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, Brazil
| | - Caroline Mota Fernandes
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY, United States
| | - Gabriela Felix Persinoti
- Laboratório Nacional de Biorrenováveis (LNBR), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas, São Paulo, Brazil
| | | | - Anderson Ferreira da Cunha
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, Brazil
| | - Gustavo Henrique Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Maurizio Del Poeta
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY, United States
- Division of Infectious Diseases, School of Medicine, Stony Brook University, Stony Brook, NY, United States
- Institute of Chemical Biology and Drug Discovery, Stony Brook University, Stony Brook, NY, United States
- Veterans Administration Medical Center, Northport, NY, United States
| | - Iran Malavazi
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, Brazil
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22
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Lee Y, Puumala E, Robbins N, Cowen LE. Antifungal Drug Resistance: Molecular Mechanisms in Candida albicans and Beyond. Chem Rev 2021; 121:3390-3411. [PMID: 32441527 PMCID: PMC8519031 DOI: 10.1021/acs.chemrev.0c00199] [Citation(s) in RCA: 335] [Impact Index Per Article: 111.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Fungal infections are a major contributor to infectious disease-related deaths across the globe. Candida species are among the most common causes of invasive mycotic disease, with Candida albicans reigning as the leading cause of invasive candidiasis. Given that fungi are eukaryotes like their human host, the number of unique molecular targets that can be exploited for antifungal development remains limited. Currently, there are only three major classes of drugs approved for the treatment of invasive mycoses, and the efficacy of these agents is compromised by the development of drug resistance in pathogen populations. Notably, the emergence of additional drug-resistant species, such as Candida auris and Candida glabrata, further threatens the limited armamentarium of antifungals available to treat these serious infections. Here, we describe our current arsenal of antifungals and elaborate on the resistance mechanisms Candida species possess that render them recalcitrant to therapeutic intervention. Finally, we highlight some of the most promising therapeutic strategies that may help combat antifungal resistance, including combination therapy, targeting fungal-virulence traits, and modulating host immunity. Overall, a thorough understanding of the mechanistic principles governing antifungal drug resistance is fundamental for the development of novel therapeutics to combat current and emerging fungal threats.
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Affiliation(s)
- Yunjin Lee
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, Ontario M5G 1M1, Canada
| | - Emily Puumala
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, Ontario M5G 1M1, Canada
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, Ontario M5G 1M1, Canada
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, Ontario M5G 1M1, Canada
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23
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Horianopoulos LC, Kronstad JW. Chaperone Networks in Fungal Pathogens of Humans. J Fungi (Basel) 2021; 7:209. [PMID: 33809191 PMCID: PMC7998936 DOI: 10.3390/jof7030209] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 03/05/2021] [Accepted: 03/10/2021] [Indexed: 12/14/2022] Open
Abstract
The heat shock proteins (HSPs) function as chaperones to facilitate proper folding and modification of proteins and are of particular importance when organisms are subjected to unfavourable conditions. The human fungal pathogens are subjected to such conditions within the context of infection as they are exposed to human body temperature as well as the host immune response. Herein, the roles of the major classes of HSPs are briefly reviewed and their known contributions in human fungal pathogens are described with a focus on Candida albicans, Cryptococcus neoformans, and Aspergillus fumigatus. The Hsp90s and Hsp70s in human fungal pathogens broadly contribute to thermotolerance, morphological changes required for virulence, and tolerance to antifungal drugs. There are also examples of J domain co-chaperones and small HSPs influencing the elaboration of virulence factors in human fungal pathogens. However, there are diverse members in these groups of chaperones and there is still much to be uncovered about their contributions to pathogenesis. These HSPs do not act in isolation, but rather they form a network with one another. Interactions between chaperones define their specific roles and enhance their protein folding capabilities. Recent efforts to characterize these HSP networks in human fungal pathogens have revealed that there are unique interactions relevant to these pathogens, particularly under stress conditions. The chaperone networks in the fungal pathogens are also emerging as key coordinators of pathogenesis and antifungal drug tolerance, suggesting that their disruption is a promising strategy for the development of antifungal therapy.
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Affiliation(s)
| | - James W. Kronstad
- Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada;
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24
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Antifungal Effect of All- trans Retinoic Acid against Aspergillus fumigatus In Vitro and in a Pulmonary Aspergillosis In Vivo Model. Antimicrob Agents Chemother 2021; 65:AAC.01874-20. [PMID: 33361288 PMCID: PMC8092556 DOI: 10.1128/aac.01874-20] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 11/24/2020] [Indexed: 01/01/2023] Open
Abstract
Aspergillus fumigatus is the most common opportunistic fungal pathogen and causes invasive pulmonary aspergillosis (IPA), with high mortality among immunosuppressed patients. The fungistatic activity of all-trans retinoic acid (ATRA) has been recently described in vitro. Aspergillus fumigatus is the most common opportunistic fungal pathogen and causes invasive pulmonary aspergillosis (IPA), with high mortality among immunosuppressed patients. The fungistatic activity of all-trans retinoic acid (ATRA) has been recently described in vitro. We evaluated the efficacy of ATRA in vivo and its potential synergistic interaction with other antifungal drugs. A rat model of IPA and in vitro experiments were performed to assess the efficacy of ATRA against Aspergillus in association with classical antifungal drugs and in silico studies used to clarify its mechanism of action. ATRA (0.5 and 1 mM) displayed a strong fungistatic activity in Aspergillus cultures, while at lower concentrations, synergistically potentiated fungistatic efficacy of subinhibitory concentration of amphotericin B (AmB) and posaconazole (POS). ATRA also enhanced macrophagic phagocytosis of conidia. In a rat model of IPA, ATRA reduced mortality similarly to posaconazole. Fungistatic efficacy of ATRA alone and synergistically with other antifungal drugs was documented in vitro, likely by inhibiting fungal heat shock protein 90 (Hsp90) expression and Hsp90-related genes. ATRA treatment reduced mortality in a model of IPA in vivo. Those findings suggest ATRA as a suitable fungistatic agent that can also reduce dosage and adverse reactions of classical antifungal drugs and add to the development of new therapeutic strategies against IPA and systemic fungal infections.
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25
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Xu JW, Liao CC, Hung KC, Wang ZY, Tung YT, Wu JH. Proteomics Reveals Octyl Gallate as an Environmentally Friendly Wood Preservative Leading to Reactive Oxygen Species-Driven Metabolic Inflexibility and Growth Inhibition in White-Rot Fungi ( Lenzites betulina and Trametes versicolor). J Fungi (Basel) 2021; 7:jof7020145. [PMID: 33671246 PMCID: PMC7923014 DOI: 10.3390/jof7020145] [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: 02/01/2021] [Revised: 02/11/2021] [Accepted: 02/13/2021] [Indexed: 12/13/2022] Open
Abstract
The most commonly applied wood preservatives are based on creosote, pentachlorophenol, and waterborne chromate copper arsenate, which negatively affect the environment. Thus, environmentally friendly wood preservatives are required. This study investigated the antifungal activity and mechanism of several long-chain alkyl gallates (3,4,5-trihydroxybenzoates) against white-rot fungi, Lenzites betulina and Trametes versicolor. The results revealed that octyl gallate (OG) had the best antifungal activity. Additionally, OG may have a mechanism of action similar to surfactants and inhibit ATPase activity, causing mitochondrial dysfunction and endogenous reactive oxygen species (ROS) production. Upon exposure to endogenous ROS, cells rapidly inhibit the synthesis of 60S ribosomal subunits, thus reducing the mycelial growth rate. L. betulina and T. versicolor also remodeled their energy metabolism in response to low ATP levels and endogenous ROS. After OG treatment, ATP citrate synthase activity was downregulated and glycolytic activity was upregulated in L. betulina. However, the activity of aerobic pathways was decreased and the oxidative branch of the pentose phosphate pathway was redirected form nicotinamide adenine dinucleotide phosphate (NADPH) to minimize endogenous ROS-mediated damage in T. versicolor. Taken together, these observations reveal that OG is a potent inhibitor of white-rot fungus. Further structural optimization research and pharmacological investigations are warranted.
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Affiliation(s)
- Jin-Wei Xu
- Department of Forestry, National Chung Hsing University, Taichung 40227, Taiwan; (J.-W.X.); (K.-C.H.); (Z.-Y.W.)
| | - Chen-Chung Liao
- Proteomics Research Center, National Yang-Ming University, Taipei 11221, Taiwan;
| | - Ke-Chang Hung
- Department of Forestry, National Chung Hsing University, Taichung 40227, Taiwan; (J.-W.X.); (K.-C.H.); (Z.-Y.W.)
| | - Zhong-Yao Wang
- Department of Forestry, National Chung Hsing University, Taichung 40227, Taiwan; (J.-W.X.); (K.-C.H.); (Z.-Y.W.)
| | - Yu-Tang Tung
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 40227, Taiwan
- Correspondence: (Y.-T.T.); (J.-H.W.)
| | - Jyh-Horng Wu
- Department of Forestry, National Chung Hsing University, Taichung 40227, Taiwan; (J.-W.X.); (K.-C.H.); (Z.-Y.W.)
- Correspondence: (Y.-T.T.); (J.-H.W.)
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Rocha MC, Minari K, Fabri JHTM, Kerkaert JD, Gava LM, da Cunha AF, Cramer RA, Borges JC, Malavazi I. Aspergillus fumigatus Hsp90 interacts with the main components of the cell wall integrity pathway and cooperates in heat shock and cell wall stress adaptation. Cell Microbiol 2021; 23:e13273. [PMID: 33010083 PMCID: PMC7855945 DOI: 10.1111/cmi.13273] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 09/12/2020] [Accepted: 09/27/2020] [Indexed: 12/18/2022]
Abstract
The initiation of Aspergillus fumigatus infection occurs via dormant conidia deposition into the airways. Therefore, conidial germination and subsequent hyphal extension and growth occur in a sustained heat shock (HS) environment promoted by the host. The cell wall integrity pathway (CWIP) and the essential eukaryotic chaperone Hsp90 are critical for fungi to survive HS. Although A. fumigatus is a thermophilic fungus, the mechanisms underpinning the HS response are not thoroughly described and important to define its role in pathogenesis, virulence and antifungal drug responses. Here, we investigate the contribution of the CWIP in A. fumigatus thermotolerance. We observed that the CWIP components PkcA, MpkA and RlmA are Hsp90 clients and that a PkcAG579R mutation abolishes this interaction. PkcAG579R also abolishes MpkA activation in the short-term response to HS. Biochemical and biophysical analyses indicated that Hsp90 is a dimeric functional ATPase, which has a higher affinity for ADP than ATP and prevents MpkA aggregation in vitro. Our data suggest that the CWIP is constitutively required for A. fumigatus to cope with the temperature increase found in the mammalian lung environment, emphasising the importance of this pathway in supporting thermotolerance and cell wall integrity.
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Affiliation(s)
- Marina Campos Rocha
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, Brazil
| | - Karine Minari
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, Brazil
- Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, Brazil
| | | | - Joshua D Kerkaert
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Lisandra Marques Gava
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, Brazil
| | - Anderson Ferreira da Cunha
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, Brazil
| | - Robert A Cramer
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Júlio César Borges
- Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, Brazil
| | - Iran Malavazi
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, Brazil
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Tits J, Cammue BPA, Thevissen K. Combination Therapy to Treat Fungal Biofilm-Based Infections. Int J Mol Sci 2020; 21:ijms21228873. [PMID: 33238622 PMCID: PMC7700406 DOI: 10.3390/ijms21228873] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 11/19/2020] [Accepted: 11/20/2020] [Indexed: 12/21/2022] Open
Abstract
An increasing number of people is affected by fungal biofilm-based infections, which are resistant to the majority of currently-used antifungal drugs. Such infections are often caused by species from the genera Candida, Aspergillus or Cryptococcus. Only a few antifungal drugs, including echinocandins and liposomal formulations of amphotericin B, are available to treat such biofilm-based fungal infections. This review discusses combination therapy as a novel antibiofilm strategy. More specifically, in vitro methods to discover new antibiofilm combinations will be discussed. Furthermore, an overview of the main modes of action of promising antibiofilm combination treatments will be provided as this knowledge may facilitate the optimization of existing antibiofilm combinations or the development of new ones with a similar mode of action.
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Paracoccidioides HSP90 Can Be Found in the Cell Surface and Is a Target for Antibodies with Therapeutic Potential. J Fungi (Basel) 2020; 6:jof6040193. [PMID: 32998395 PMCID: PMC7712200 DOI: 10.3390/jof6040193] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 09/05/2020] [Accepted: 09/10/2020] [Indexed: 11/17/2022] Open
Abstract
Paracoccidioidomycosis (PCM) is one of the most frequent systemic mycoses in Latin America. It affects mainly male rural workers in impoverished regions, and the therapy can last up to two years or use drugs that are very toxic. Given the need for novel safe and effective approaches to treat PCM, we have been developing monoclonal antibodies (mAbs) that could be used not only to block specific fungal targets, but also modulate the host’s antifungal immunity. In this work we show the generation of and promising results with an mAb against Heat Shock Protein (HSP)90, a molecular chaperone that is an important virulence factor in fungi. Using recombinant Paracoccidioides lutzii (Pb01) and P. brasiliensis (Pb18) HSP90 proteins produced in E. coli, we immunized mice and generated polyclonal antibodies and an IgG1 hybridoma mAb. The proteins were very immunogenic and both the polyclonal serum and mAb were used in immunofluorescence experiments, which showed binding of antibodies to the yeast cell surface. The mAb successfully opsonized P. lutzii and P. brasiliensis cells in co-incubations with J774.16 macrophage-like cells. Our results suggest that this mAb could serve as the basis for new immunotherapy regimens for PCM.
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LeBlanc EV, Polvi EJ, Veri AO, Privé GG, Cowen LE. Structure-guided approaches to targeting stress responses in human fungal pathogens. J Biol Chem 2020; 295:14458-14472. [PMID: 32796038 DOI: 10.1074/jbc.rev120.013731] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 08/11/2020] [Indexed: 11/06/2022] Open
Abstract
Fungi inhabit extraordinarily diverse ecological niches, including the human body. Invasive fungal infections have a devastating impact on human health worldwide, killing ∼1.5 million individuals annually. The majority of these deaths are attributable to species of Candida, Cryptococcus, and Aspergillus Treating fungal infections is challenging, in part due to the emergence of resistance to our limited arsenal of antifungal agents, necessitating the development of novel therapeutic options. Whereas conventional antifungal strategies target proteins or cellular components essential for fungal growth, an attractive alternative strategy involves targeting proteins that regulate fungal virulence or antifungal drug resistance, such as regulators of fungal stress responses. Stress response networks enable fungi to adapt, grow, and cause disease in humans and include regulators that are highly conserved across eukaryotes as well as those that are fungal-specific. This review highlights recent developments in elucidating crystal structures of fungal stress response regulators and emphasizes how this knowledge can guide the design of fungal-selective inhibitors. We focus on the progress that has been made with highly conserved regulators, including the molecular chaperone Hsp90, the protein phosphatase calcineurin, and the small GTPase Ras1, as well as with divergent stress response regulators, including the cell wall kinase Yck2 and trehalose synthases. Exploring structures of these important fungal stress regulators will accelerate the design of selective antifungals that can be deployed to combat life-threatening fungal diseases.
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Affiliation(s)
- Emmanuelle V LeBlanc
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Elizabeth J Polvi
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Amanda O Veri
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Gilbert G Privé
- Departments of Medical Biophysics and Biochemistry, University of Toronto, Toronto, Ontario, Canada.,Princess Margaret Cancer Centre, Toronto, Ontario, Canada
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
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Ma Y, Ji Y, Yang J, Li W, Li J, Cen W, Wang Y, Feng W. Deletion of bem46 retards spore germination and may be related to the polar growth of Aspergillus fumigatus. Med Mycol 2020; 58:690-697. [PMID: 31711175 DOI: 10.1093/mmy/myz108] [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: 05/22/2019] [Revised: 10/08/2019] [Accepted: 10/15/2019] [Indexed: 11/13/2022] Open
Abstract
Bud emergence 46 (BEM46), a member of the α/β hydrolase superfamily, has been reported to be essential for polarized growth in Neurospora crassa. However, the role of BEM46 in aspergillus fumigatus (A. fumigatus) remains unclear. In this study, we constructed an A. fumigatus strain expressing BEM46 fused with enhanced green fluorescent protein, and a Δbem46 mutant, to explore the localization and the role of growth of BEM46 in A. fumigatus, respectively. Confocal laser scanning microscopy revealed that BEM46 was dominantly expressed in the sites where hyphae germinated from conidia in A. fumigatus. When compared with the control strain, the Δbem46 mutant exhibited insignificant morphological changes but delayed germination. No significant changes were found regarding the radial growth of both strains in response to various antifungal agents. These results suggest that BEM46 plays an essential role in timely germination in A. fumigatus. From the observation of fluorescence localization, we infer that that BEM46 might be involved in polarized growth in A. fumigatus.
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Affiliation(s)
- Yan Ma
- Department of Dermatology, The Second Hospital of Shanxi Medical University, Taiyuan, Shanxi, China
| | - Ying Ji
- Department of Dermatology, The Second Hospital of Shanxi Medical University, Taiyuan, Shanxi, China
| | - Jing Yang
- Department of Dermatology, The Second Hospital of Shanxi Medical University, Taiyuan, Shanxi, China
| | - Wen Li
- Department of Dermatology, The Second Hospital of Shanxi Medical University, Taiyuan, Shanxi, China
| | - Jiajuan Li
- Department of Dermatology, The Second Hospital of Shanxi Medical University, Taiyuan, Shanxi, China
| | - Wen Cen
- Department of Dermatology, The Second Hospital of Shanxi Medical University, Taiyuan, Shanxi, China
| | - Yan Wang
- Department of Dermatology, The Second Hospital of Shanxi Medical University, Taiyuan, Shanxi, China
| | - Wenli Feng
- Department of Dermatology, The Second Hospital of Shanxi Medical University, Taiyuan, Shanxi, China
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Navarro MV, Chaves AFA, Castilho DG, Casula I, Calado JCP, Conceição PM, Iwai LK, de Castro BF, Batista WL. Effect of Nitrosative Stress on the S-Nitroso-Proteome of Paracoccidioides brasiliensis. Front Microbiol 2020; 11:1184. [PMID: 32582109 PMCID: PMC7287035 DOI: 10.3389/fmicb.2020.01184] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Accepted: 05/08/2020] [Indexed: 12/12/2022] Open
Abstract
The fungi Paracoccidioides brasiliensis and Paracoccidioides lutzii are the causative agents of paracoccidioidomycosis (PCM), a systemic mycosis endemic to Latin America. This fungus is considered a facultative intracellular pathogen that is able to survive and replicate inside macrophages. The survival of the fungus during infection depends on its adaptability to various conditions, such as nitrosative/oxidative stress produced by the host immune cells, particularly alveolar macrophages. Currently, there is little knowledge about the Paracoccidioides spp. signaling pathways involved in the fungus evasion mechanism of the host defense response. However, it is known that some of these pathways are triggered by reactive oxygen species and reactive nitrogen species (ROS/RNS) produced by host cells. Considering that the effects of NO (nitric oxide) on pathogens are concentration dependent, such effects could alter the redox state of cysteine residues by influencing (activating or inhibiting) a variety of protein functions, notably S-nitrosylation, a highly important NO-dependent posttranslational modification that regulates cellular functions and signaling pathways. It has been demonstrated by our group that P. brasiliensis yeast cells proliferate when exposed to low NO concentrations. Thus, this work investigated the modulation profile of S-nitrosylated proteins of P. brasiliensis, as well as identifying S-nitrosylation sites after treatment with RNS. Through mass spectrometry analysis (LC-MS/MS) and label-free quantification, it was possible to identify 474 proteins in the S-nitrosylated proteome study. With this approach, we observed that proteins treated with NO at low concentrations presented a proliferative response pattern, with several proteins involved in cellular cycle regulation and growth being activated. These proteins appear to play important roles in fungal virulence. On the other hand, fungus stimulated by high NO concentrations exhibited a survival response pattern. Among these S-nitrosylated proteins we identified several potential molecular targets for fungal disease therapy, including cell wall integrity (CWI) pathway, amino acid and folic acid metabolisms. In addition, we detected that the transnitrosylation/denitrosylation redox signaling are preserved in this fungus. Finally, this work may help to uncover the beneficial and antifungal properties of NO in the P. brasiliensis and point to useful targets for the development of antifungal drugs.
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Affiliation(s)
- Marina V. Navarro
- Department of Microbiology, Immunology and Parasitology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Alison F. A. Chaves
- Department of Microbiology, Immunology and Parasitology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Daniele G. Castilho
- Department of Microbiology, Immunology and Parasitology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Isis Casula
- Department of Pharmaceutical Sciences, Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Diadema, Brazil
| | - Juliana C. P. Calado
- Department of Microbiology, Immunology and Parasitology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Palloma M. Conceição
- Department of Pharmaceutical Sciences, Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Diadema, Brazil
| | - Leo K. Iwai
- Laboratory of Applied Toxinology, Center of Toxins, Immune-response and Cell Signaling, Instituto Butantan, São Paulo, Brazil
| | - Beatriz F. de Castro
- Department of Pharmaceutical Sciences, Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Diadema, Brazil
| | - Wagner L. Batista
- Department of Microbiology, Immunology and Parasitology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
- Department of Pharmaceutical Sciences, Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Diadema, Brazil
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Abstract
Aspergillus fumigatus is an opportunistic and allergenic pathogenic fungus, responsible for fungal infections in humans. A. fumigatus infections are usually treated with polyenes, azoles, or echinocandins. Echinocandins, such as caspofungin, can inhibit the biosynthesis of the β-1,3-glucan polysaccharide, affecting the integrity of the cell wall and leading to fungal death. In some A. fumigatus strains, caspofungin treatment at high concentrations induces an increase of fungal growth, a phenomenon called the caspofungin paradoxical effect (CPE). Here, we analyze the proteome and phosphoproteome of the A. fumigatus wild-type strain and of mitogen-activated protein kinase (MAPK) mpkA and sakA null mutant strains during CPE (2 μg/ml caspofungin for 1 h). The wild-type proteome showed 75 proteins and 814 phosphopeptides (corresponding to 520 proteins) altered in abundance in response to caspofungin treatment. The ΔmpkA (ΔmpkA caspofungin/wild-type caspofungin) and ΔsakA (ΔsakA caspofungin/wild-type caspofungin) strains displayed 626 proteins and 1,236 phosphopeptides (corresponding to 703 proteins) and 101 proteins and 1,217 phosphopeptides (corresponding to 645 proteins), respectively, altered in abundance. Functional characterization of the phosphopeptides from the wild-type strain exposed to caspofungin showed enrichment for transcription factors, protein kinases, and cytoskeleton proteins. Proteomic analysis of the ΔmpkA and ΔsakA mutants indicated that control of proteins involved in metabolism, such as in production of secondary metabolites, was highly represented in both mutants. Results of functional categorization of phosphopeptides from both mutants were very similar and showed a high number of proteins with decreased phosphorylation of proteins involved in transcriptional control, DNA/RNA binding, cell cycle control, and DNA processing. This report reveals novel transcription factors involved in caspofungin tolerance.IMPORTANCE Aspergillus fumigatus is an opportunistic human-pathogenic fungus causing allergic reactions or systemic infections, such as invasive pulmonary aspergillosis in immunocompromised patients. Caspofungin is an echinocandin that impacts the construction of the fungal cell wall by inhibiting the biosynthesis of the β-1,3-glucan polysaccharide. Caspofungin is a fungistatic drug and is recommended as a second-line therapy for treatment of aspergillosis. Treatment at high concentrations induces an increase of fungal growth, a phenomenon called the caspofungin paradoxical effect (CPE). Collaboration between the mitogen-activated protein kinases (MAPK) of the cell wall integrity (MapkA) and high-osmolarity glycerol (SakA) pathways is essential for CPE. Here, we investigate the global proteome and phosphoproteome of A. fumigatus wild-type, ΔmpkA, and ΔsakA strains upon CPE. This study showed intense cross talk between the two MAPKs for the CPE and identified novel protein kinases and transcription factors possibly important for CPE. Increased understanding of how the modulation of protein phosphorylation may affect the fungal growth in the presence of caspofungin represents an important step in the development of new strategies and methods to combat the fungus inside the host.
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Deng X, Du B, Zhu F, Gao Y, Li J. Proteomic analysis of Aspergillus niger 3.316 under heat stress. Microbiologyopen 2020; 9:e1012. [PMID: 32107876 PMCID: PMC7221434 DOI: 10.1002/mbo3.1012] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 01/25/2020] [Accepted: 02/01/2020] [Indexed: 01/04/2023] Open
Abstract
β-Glucosidase production by Aspergillus niger is accompanied by an inevitable temperature increase in the industrial fermentation environment. Hence, the synthetic process of β-glucosidase is negatively affected. However, our understanding of the heat stress response (HSR) mechanism in A. niger is still incomplete. The current study explored the intracellular proteome profile of A. niger 3.316 in group T (50°C stress) and group C (30°C control) using two proteomic approaches (isobaric tags for relative and absolute quantitation [iTRAQ] and label-free) and examined the expression of four proteins using a parallel reaction monitoring (PRM) approach. Based on the result of the iTRAQ proteomic analysis, 1,025 proteins were differentially expressed in group T compared to group C. Using the label-free approach, we only focused on 77 proteins with significant changes in their protein expression levels. In addition, we performed bioinformatics analysis on all these proteins and obtained detailed gene ontology (GO) enrichment and Kyoto encyclopedia of genes and genomes (KEGG) pathway results. Under heat stress conditions, the relative expression levels of proteins with protection and repair functions were upregulated in A. niger 3.316. These proteins were involved in metabolic pathways, oxidative phosphorylation, porphyrin and chlorophyll metabolism, pyruvate metabolism, and the citrate cycle (TCA cycle). The insights obtained from the presented proteomics and bioinformatics analyses can be used to further explore the HSR mechanism of A. niger.
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Affiliation(s)
- Xiangyu Deng
- Hebei Normal University of Science and TechnologyCollege of Food Science and TechnologyQinhuangdaoChina
| | - Bin Du
- Hebei Normal University of Science and TechnologyCollege of Food Science and TechnologyQinhuangdaoChina
| | - Fengmei Zhu
- Hebei Normal University of Science and TechnologyCollege of Food Science and TechnologyQinhuangdaoChina
| | - Yanan Gao
- Hebei Normal University of Science and TechnologyCollege of Food Science and TechnologyQinhuangdaoChina
| | - Jun Li
- Hebei Normal University of Science and TechnologyCollege of Food Science and TechnologyQinhuangdaoChina
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Tu B, Yin G, Li H. Synergistic effects of vorinostat (SAHA) and azoles against Aspergillus species and their biofilms. BMC Microbiol 2020; 20:28. [PMID: 32028887 PMCID: PMC7006160 DOI: 10.1186/s12866-020-1718-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 01/30/2020] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Invasive aspergillosis is a fungal infection that occurs mainly in immunocompromised patients. It is responsible for a high degree of mortality and is invariably unresponsive to conventional antifungal treatments. Histone deacetylase inhibitors can affect the cell cycle, apoptosis and differentiation. The histone deacetylase inhibitor vorinostat (SAHA) has recently received approval for the treatment of cutaneous T cell lymphoma. Here, we investigated the interactions of SAHA and itraconazole, voriconazole, and posaconazole against Aspergillus spp. in vitro using both planktonic cells and biofilms. RESULTS We investigated 20 clinical strains using broth microdilution checkerboard methods. The results showed synergy between SAHA and itraconazole, voriconazole, and posaconazole against 60, 40, and 25% of tested isolates of planktonic Aspergillus spp., respectively. Similar synergy was also observed against Aspergillus biofilms. The expression of the azole-associated multidrug efflux pumps MDR1, MDR2, MDR3 and MDR4, as well as that of HSP90, was measured by RT-PCR. The results indicated that the molecular mechanism of the observed synergistic effects in Aspergillus fumigatus may be partly associated with dampened expression of the efflux pump genes and, furthermore, that HSP90 suppression may be a major contributor to the observed synergistic effects of the drugs. CONCLUSIONS SAHA has potential as a secondary treatment to enhance the effects of azoles against both biofilm and planktonic cells of Aspergillus spp. in vitro. This effect occurs mostly by inhibition of HSP90 expression.
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Affiliation(s)
- Bo Tu
- Department of Otorhinolaryngology and Head Neck Surgery, the First Affiliated Hospital of Jinan University, Guangzhou, 510630 Guangdong People’s Republic of China
| | - Gendi Yin
- Department of Otolaryngology Head Neck Surgery, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510630 Guangdong People’s Republic of China
| | - Hui Li
- Department of Otorhinolaryngology and Head Neck Surgery, the First Affiliated Hospital of Jinan University, Guangzhou, 510630 Guangdong People’s Republic of China
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Abstract
Aspergilli produce conidia for reproduction or to survive hostile conditions, and they are highly effective in the distribution of conidia through the environment. In immunocompromised individuals, inhaled conidia can germinate inside the respiratory tract, which may result in invasive pulmonary aspergillosis. The management of invasive aspergillosis has become more complex, with new risk groups being identified and the emergence of antifungal resistance. Patient survival is threatened by these developments, stressing the need for alternative therapeutic strategies. As germination is crucial for infection, prevention of this process might be a feasible approach. A broader understanding of conidial germination is important to identify novel antigermination targets. In this review, we describe conidial resistance against various stresses, transition from dormant conidia to hyphal growth, the underlying molecular mechanisms involved in germination of the most common Aspergillus species, and promising antigermination targets. Germination of Aspergillus is characterized by three morphotypes: dormancy, isotropic growth, and polarized growth. Intra- and extracellular proteins play an important role in the protection against unfavorable environmental conditions. Isotropically expanding conidia remodel the cell wall, and biosynthetic machineries are needed for cellular growth. These biosynthetic machineries are also important during polarized growth, together with tip formation and the cell cycle machinery. Genes involved in isotropic and polarized growth could be effective antigermination targets. Transcriptomic and proteomic studies on specific Aspergillus morphotypes will improve our understanding of the germination process and allow discovery of novel antigermination targets and biomarkers for early diagnosis and therapy.
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Heat shock proteins in infection. Clin Chim Acta 2019; 498:90-100. [PMID: 31437446 DOI: 10.1016/j.cca.2019.08.015] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Revised: 08/14/2019] [Accepted: 08/16/2019] [Indexed: 12/18/2022]
Abstract
Heat shock proteins (HSPs) are constitutively expressed under physiological conditions in most organisms but their expression can significantly enhance in response to four types of stimuli including physical (e.g., radiation or heat shock), chemical and microbial (e.g., pathogenic bacteria, viruses, parasites and fungi) stimuli, and also dietary. These proteins were identified for their role in protecting cells from high temperature and other forms of stress. HSPs control physiological activities or virulence through interaction with various regulators of cellular signaling pathways. Several roles were determined for HSPs in the immune system including intracellular roles (e.g., antigen presentation and expression of innate receptors) as well as extracellular roles (e.g., tumor immunosurveillance and autoimmunity). It was observed that exogenously administered HSPs induced various immune responses in immunotherapy of cancer, infectious diseases, and autoimmunity. Moreover, virus interaction with HSPs as molecular chaperones showed important roles in regulating viral infections including cell entry and nuclear import, viral replication and gene expression, folding/assembly of viral protein, apoptosis regulation, and host immunity. Viruses could regulate host HSPs at different levels such as transcription, translation, post-translational modification and cellular localization. In this review, we attempt to overview the roles of HSPs in a variety of infectious diseases.
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Echinocandins for the Treatment of Invasive Aspergillosis: from Laboratory to Bedside. Antimicrob Agents Chemother 2019; 63:AAC.00399-19. [PMID: 31138565 DOI: 10.1128/aac.00399-19] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Echinocandins (caspofungin, micafungin, anidulafungin), targeting β-1,3-glucan synthesis of the cell wall, represent one of the three currently available antifungal drug classes for the treatment of invasive fungal infections. Despite their limited antifungal activity against Aspergillus spp., echinocandins are considered an alternative option for the treatment of invasive aspergillosis (IA). This drug class exhibits several advantages, such as excellent tolerability and its potential for synergistic interactions with some other antifungals. The objective of this review is to discuss the in vitro and clinical efficacy of echinocandins against Aspergillus spp., considering the complex interactions between the drug, the mold, and the host. The antifungal effect of echinocandins is not limited to direct inhibition of hyphal growth but also induces an immunomodulatory effect on the host's response. Moreover, Aspergillus spp. have developed important adaptive mechanisms of tolerance to survive and overcome the action of echinocandins, such as paradoxical growth at increased concentrations. This stress response can be abolished by several compounds that potentiate the activity of echinocandins, such as drugs targeting the heat shock protein 90 (Hsp90)-calcineurin axis, opening perspectives for adjuvant therapies. Finally, the present and future places of echinocandins as prophylaxis, monotherapy, or combination therapy of IA are discussed in view of the emergence of pan-azole resistance among Aspergillus fumigatus isolates, the occurrence of breakthrough IA, and the advent of new long-lasting echinocandins (rezafungin) or other β-1,3-glucan synthase inhibitors (ibrexafungerp).
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Schubert M, Xue S, Ebel F, Vaggelas A, Krylov VB, Nifantiev NE, Chudobová I, Schillberg S, Nölke G. Monoclonal Antibody AP3 Binds Galactomannan Antigens Displayed by the Pathogens Aspergillus flavus, A. fumigatus, and A. parasiticus. Front Cell Infect Microbiol 2019; 9:234. [PMID: 31380292 PMCID: PMC6646516 DOI: 10.3389/fcimb.2019.00234] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 06/14/2019] [Indexed: 12/16/2022] Open
Abstract
Aspergillus fumigatus and A. flavus are the fungal pathogens responsible for most cases of invasive aspergillosis (IA). Early detection of the circulating antigen galactomannan (GM) in serum allows the prompt application of effective antifungal therapy, thus improving the survival rate of IA patients. However, the use of monoclonal antibodies (mAbs) for the diagnosis of IA is often associated with false positives due to cross-reaction with bacterial polysaccharides. More specific antibodies are therefore needed. Here we describe the characterization of the Aspergillus-specific mAb AP3 (IgG1κ), including the precise identification of its corresponding antigen. The antibody was generated using A. parasiticus cell wall fragments and was shown to bind several Aspergillus species. Immunofluorescence microscopy revealed that AP3 binds a cell wall antigen, but immunoprecipitation and enzyme-linked immunosorbent assays showed that the antigen is also secreted into the culture medium. The inability of AP3 to bind the A. fumigatus galactofuranose (Galf )-deficient mutant ΔglfA confirmed that Galf residues are part of the epitope. Several lines of evidence strongly indicated that AP3 recognizes the Galf residues of O-linked glycans on Aspergillus proteins. Glycoarray analysis revealed that AP3 recognizes oligo-[β-D-Galf-1,5] sequences containing four or more residues with longer chains more efficiently. We also showed that AP3 captures GM in serum, suggesting it may be useful as a diagnostic tool for patients with IA.
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Affiliation(s)
- Max Schubert
- Department of Plant Biotechnology, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
| | - Sheng Xue
- Institute for Translational Medicine, College of Medicine, Qingdao University, Qingdao, China
| | - Frank Ebel
- Faculty of Veterinary Medicine, Institute for Infectious Diseases and Zoonoses, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Annegret Vaggelas
- Faculty of Veterinary Medicine, Institute for Infectious Diseases and Zoonoses, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Vadim B Krylov
- N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Nikolay E Nifantiev
- N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Ivana Chudobová
- Department of Plant Biotechnology, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
| | - Stefan Schillberg
- Department of Plant Biotechnology, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany.,Institute for Phytopathology, Justus Liebig University Giessen, Giessen, Germany
| | - Greta Nölke
- Department of Plant Biotechnology, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
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Vahedi Shahandashti R, Lass-Flörl C. Antifungal resistance in Aspergillus terreus: A current scenario. Fungal Genet Biol 2019; 131:103247. [PMID: 31247322 DOI: 10.1016/j.fgb.2019.103247] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 06/20/2019] [Indexed: 12/31/2022]
Abstract
Invasive aspergillosis caused by intrinsically resistant non-fumigatus Aspergillus species displays a poor outcome in immunocompromised patients. The polyene antifungal amphotericin B (AmB) remains to be "gold standard" in the treatment of invasive fungal infections. Aspergillus terreus is innately resistant to AmB, in vivo and in vitro. Till now, the exact mode of action in polyene resistance is not well understood. This review highlights the underlying molecular basis of AmB resistance in A. terreus, displaying data obtained from AmB susceptible A. terreus and AmB resistant A. terreus strains. The effect of AmB on main cellular and molecular functions such as fungal respiration and stress response pathways will be discussed in detail and resistance mechanisms will be highlighted. The fungal stress response machinery seems to be a major player in the onset of AmB resistance in A. terreus.
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Affiliation(s)
| | - Cornelia Lass-Flörl
- Division of Hygiene and Medical Microbiology, Medical University Innsbruck, Innsbruck, Austria.
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Link between Heat Shock Protein 90 and the Mitochondrial Respiratory Chain in the Caspofungin Stress Response of Aspergillus fumigatus. Antimicrob Agents Chemother 2019; 63:AAC.00208-19. [PMID: 31061164 DOI: 10.1128/aac.00208-19] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 04/12/2019] [Indexed: 12/12/2022] Open
Abstract
Aspergillus fumigatus is an opportunistic mold responsible for invasive aspergillosis. Triazoles (e.g., voriconazole) represent the first-line treatment, but emerging resistance is of concern. The echinocandin drug caspofungin is used as second-line treatment but has limited efficacy. The heat shock protein 90 (Hsp90) orchestrates the caspofungin stress response and is the trigger of an adaptive phenomenon called the paradoxical effect (growth recovery at increasing caspofungin concentrations). The aim of this study was to elucidate the Hsp90-dependent mechanisms of the caspofungin stress response. Transcriptomic profiles of the wild-type A. fumigatus strain (KU80) were compared to those of a mutant strain with substitution of the native hsp90 promoter by the thiA promoter (pthiA-hsp90), which lacks the caspofungin paradoxical effect. Caspofungin induced expression of the genes of the mitochondrial respiratory chain (MRC), in particular, NADH-ubiquinone oxidoreductases (complex I), in KU80 but not in the pthiA-hsp90 mutant. The caspofungin paradoxical effect could be abolished by rotenone (MRC complex I inhibitor) in KU80, supporting the role of MRC in the caspofungin stress response. Fluorescent staining of active mitochondria and measurement of oxygen consumption and ATP production confirmed the activation of the MRC in KU80 in response to caspofungin, but this activity was impaired in the pthiA-hsp90 mutant. Using a bioluminescent reporter for the measurement of intracellular calcium, we demonstrated that inhibition of Hsp90 by geldanamycin or MRC complex I by rotenone prevented the increase in intracellular calcium shown to be essential for the caspofungin paradoxical effect. In conclusion, our data support a role of the MRC in the caspofungin stress response which is dependent on Hsp90.
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Aspergillus flavus NRRL 35739, a Poor Biocontrol Agent, May Have Increased Relative Expression of Stress Response Genes. J Fungi (Basel) 2019; 5:jof5020053. [PMID: 31226781 PMCID: PMC6616650 DOI: 10.3390/jof5020053] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Revised: 06/16/2019] [Accepted: 06/18/2019] [Indexed: 12/21/2022] Open
Abstract
Biocontrol of the mycotoxin aflatoxin utilizes non-aflatoxigenic strains of Aspergillus flavus, which have variable success rates as biocontrol agents. One non-aflatoxigenic strain, NRRL 35739, is a notably poor biocontrol agent. Its growth in artificial cultures and on peanut kernels was found to be slower than that of two aflatoxigenic strains, and NRRL 35739 exhibited less sporulation when grown on peanuts. The non-aflatoxigenic strain did not greatly prevent aflatoxin accumulation. Comparison of the transcriptomes of aflatoxigenic and non-aflatoxigenic A. flavus strains AF36, AF70, NRRL 3357, NRRL 35739, and WRRL 1519 indicated that strain NRRL 35739 had increased relative expression of six heat shock and stress response proteins, with the genes having relative read counts in NRRL 35739 that were 25 to 410 times more than in the other four strains. These preliminary findings tracked with current thought that aflatoxin biocontrol efficacy is related to the ability of a non-aflatoxigenic strain to out-compete aflatoxigenic ones. The slower growth of NRRL 35739 might be due to lower stress tolerance or overexpression of stress response(s). Further study of NRRL 35739 is needed to refine our understanding of the genetic basis of competitiveness among A. flavus strains.
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Genetic Analysis of Candida auris Implicates Hsp90 in Morphogenesis and Azole Tolerance and Cdr1 in Azole Resistance. mBio 2019; 10:mBio.02529-18. [PMID: 30696744 PMCID: PMC6355988 DOI: 10.1128/mbio.02529-18] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Candida auris is an emerging fungal pathogen and a serious global health threat as the majority of clinical isolates display elevated resistance to currently available antifungal drugs. Despite the increased prevalence of C. auris infections, the mechanisms governing drug resistance remain largely elusive. In diverse fungi, the evolution of drug resistance is enabled by the essential molecular chaperone Hsp90, which stabilizes key regulators of cellular responses to drug-induced stress. Hsp90 also orchestrates temperature-dependent morphogenesis in Candida albicans, a key virulence trait. However, the role of Hsp90 in the pathobiology of C. auris remains unknown. In order to study regulatory functions of Hsp90 in C. auris, we placed HSP90 under the control of a doxycycline-repressible promoter to enable transcriptional repression. We found that Hsp90 is essential for growth in C. auris and that it enables tolerance of clinical isolates with respect to the azoles, which inhibit biosynthesis of the membrane sterol ergosterol. High-level azole resistance was independent of Hsp90 but dependent on the ABC transporter CDR1, deletion of which resulted in abrogated resistance. Strikingly, we discovered that C. auris undergoes a morphogenetic transition from yeast to filamentous growth in response to HSP90 depletion or cell cycle arrest but not in response to other cues that induce C. albicans filamentation. Finally, we observed that this developmental transition is associated with global transcriptional changes, including the induction of cell wall-related genes. Overall, this report provides a novel insight into mechanisms of drug tolerance and resistance in C. auris and describes a developmental transition in response to perturbation of a core regulator of protein homeostasis.IMPORTANCE Fungal pathogens pose a serious threat to public health. Candida auris is an emerging fungal pathogen that is often resistant to commonly used antifungal drugs. However, the mechanisms governing drug resistance and virulence in this organism remain largely unexplored. In this study, we adapted a conditional expression system to modulate the transcription of an essential gene, HSP90, which regulates antifungal resistance and virulence in diverse fungal pathogens. We showed that Hsp90 is essential for growth in C. auris and is important for tolerance of the clinically important azole antifungals, which block ergosterol biosynthesis. Further, we established that the Cdr1 efflux transporter regulates azole resistance. Finally, we discovered that C. auris transitions from yeast to filamentous growth in response to Hsp90 inhibition, accompanied by global transcriptional remodeling. Overall, this work provides a novel insight into mechanisms regulating azole resistance in C. auris and uncovers a distinct developmental program regulated by Hsp90.
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Posch W, Blatzer M, Wilflingseder D, Lass-Flörl C. Aspergillus terreus: Novel lessons learned on amphotericin B resistance. Med Mycol 2018. [PMID: 29538736 DOI: 10.1093/mmy/myx119] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The polyene antifungal amphotericin B (AmB) exerts a powerful and broad activity against a vast array of fungi and in general displays a remarkably low rate of antimicrobial resistance. Aspergillus terreus holds an exceptional position among the Aspergilli due to its intrinsic AmB resistance, in vivo and in vitro. Until now, the underlying mechanisms of polyene resistance were not well understood. This review will highlight the molecular basis of A. terreus and AmB resistance recently gained and will display novel data on the mode of action of AmB. A main focus is set on fundamental stress response pathways covering the heat shock proteins (Hsp) 90/Hsp70 axis, as well as reactive oxygen species detoxifying enzymes in response to AmB. The effect on main cellular functions such as fungal respiration will be addressed in detail and resistance mechanisms will be highlighted. Based on these novel findings we will discuss new molecular targets for alternative options in the treatment of invasive infections due to A. terreus.
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Affiliation(s)
- Wilfried Posch
- Medical University of Innsbruck, Division of Hygiene and Medical Microbiology, Schöpfstrasse 41, A- 6020 Innsbruck, Austria
| | - Michael Blatzer
- Medical University of Innsbruck, Division of Hygiene and Medical Microbiology, Schöpfstrasse 41, A- 6020 Innsbruck, Austria
| | - Doris Wilflingseder
- Medical University of Innsbruck, Division of Hygiene and Medical Microbiology, Schöpfstrasse 41, A- 6020 Innsbruck, Austria
| | - Cornelia Lass-Flörl
- Medical University of Innsbruck, Division of Hygiene and Medical Microbiology, Schöpfstrasse 41, A- 6020 Innsbruck, Austria.,ISHAM Aspergillus terreus Working Group
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Rocha MC, Santos CA, Malavazi I. The Regulatory Function of the Molecular Chaperone Hsp90 in the Cell Wall Integrity of Pathogenic Fungi. CURR PROTEOMICS 2018. [DOI: 10.2174/1570164615666180820155807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Different signaling cascades including the Cell Wall Integrity (CWI), the High Osmolarity Glycerol (HOG) and the Ca2+/calcineurin pathways control the cell wall biosynthesis and remodeling in fungi. Pathogenic fungi, such as Aspergillus fumigatus and Candida albicans, greatly rely on these signaling circuits to cope with different sources of stress, including the cell wall stress evoked by antifungal drugs and the host’s response during infection. Hsp90 has been proposed as an important regulatory protein and an attractive target for antifungal therapy since it stabilizes major effector proteins that act in the CWI, HOG and Ca2+/calcineurin pathways. Data from the human pathogen C. albicans have provided solid evidence that loss-of-function of Hsp90 impairs the evolution of resistance to azoles and echinocandin drugs. In A. fumigatus, Hsp90 is also required for cell wall integrity maintenance, reinforcing a coordinated function of the CWI pathway and this essential molecular chaperone. In this review, we focus on the current information about how Hsp90 impacts the aforementioned signaling pathways and consequently the homeostasis and maintenance of the cell wall, highlighting this cellular event as a key mechanism underlying antifungal therapy based on Hsp90 inhibition.
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Affiliation(s)
- Marina Campos Rocha
- Departmento de Genetica e Evolucao, Centro de Ciencias Biologicas e da Saude, Universidade Federal de Sao Carlos, Sao Carlos, Brazil
| | - Camilla Alves Santos
- Departmento de Genetica e Evolucao, Centro de Ciencias Biologicas e da Saude, Universidade Federal de Sao Carlos, Sao Carlos, Brazil
| | - Iran Malavazi
- Departmento de Genetica e Evolucao, Centro de Ciencias Biologicas e da Saude, Universidade Federal de Sao Carlos, Sao Carlos, Brazil
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Gaziano R, Campione E, Iacovelli F, Marino D, Pica F, Di Francesco P, Aquaro S, Menichini F, Falconi M, Bianchi L. Antifungal activity of Cardiospermum halicacabum L. (Sapindaceae) against Trichophyton rubrum occurs through molecular interaction with fungal Hsp90. DRUG DESIGN DEVELOPMENT AND THERAPY 2018; 12:2185-2193. [PMID: 30034223 PMCID: PMC6047602 DOI: 10.2147/dddt.s155610] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Introduction Dermatophytosis is a superficial fungal infection limited to the stratum corneum of the epidermis, or to the hair and nails, and constitutes an important public health problem because of its high prevalence and associated morbidity. Dermatophyte fungi, especially 2 species, Trichophyton rubrum and Trichophyton mentagrophytes, are the predominant pathogens. Topical antifungal drugs, mainly azoles or allyamines, are currently used for the treatment of dermatophytoses, although in some cases, such as in nail and hair involvement, systemic treatment is required. However, therapeutic efficacy of current antifungal agents can be limited by their side effects, costs, and the emergence of drug resistance among fungi. Plant extracts represent a potential source of active antimicrobial agents, due to the presence of a variety of chemical bioactive compounds. In the present work, we evaluated in silico and in vitro the antifungal activity of an extract of the medicinal plant Cardiospermum halicacabum against T. rubrum suggesting a potential interaction with Hsp90 as playing an important role in both pathogenicity and drug susceptibility of T. rubrum. Methods We investigated in vitro the effect of different concentrations of C. halicacabum (from 500 to 31.25 µg) against a clinical isolate of T. rubrum. Furthermore, using a computational assessment, the interaction between different C. halicacabum active compounds and the fungal Hsp90 was also investigated. Results Our results indicate a clear-cut antifungal activity of the total plant extract at the highest concentrations (500 and 250 µg). Among all tested C. halicacabum compounds, the luteolin and rutin molecules have been identified in silico as the most important potential inhibitors of Hsp90. Based on these data, luteolin and rutin were also individually assessed for their antifungal activity. Results demonstrate that both substances display an antifungal effect, even if lower than that of the total plant extract. Conclusion Our data indicate a strong fungistatic effect of C. halicacabum against T. rubrum, suggesting its potential therapeutic efficacy in the treatment of dermatophytoses. Additionally, C. halicacabum compounds, and particularly luteolin and rutin, are all possible Hsp90 interactors, explaining their fungistatic activity.
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Affiliation(s)
- Roberta Gaziano
- Microbiology Section, Department of Experimental Medicine and Surgery, University of Rome 'Tor Vergata', Rome, Italy
| | - Elena Campione
- Department of Systems Medicine, University of Rome 'Tor Vergata', Rome, Italy,
| | | | - Daniele Marino
- Microbiology Section, Department of Experimental Medicine and Surgery, University of Rome 'Tor Vergata', Rome, Italy
| | - Francesca Pica
- Microbiology Section, Department of Experimental Medicine and Surgery, University of Rome 'Tor Vergata', Rome, Italy
| | - Paolo Di Francesco
- Microbiology Section, Department of Experimental Medicine and Surgery, University of Rome 'Tor Vergata', Rome, Italy
| | - Stefano Aquaro
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Rende, Italy
| | - Francesco Menichini
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Rende, Italy
| | - Mattia Falconi
- Department of Biology, University of Rome 'Tor Vergata', Rome, Italy,
| | - Luca Bianchi
- Department of Systems Medicine, University of Rome 'Tor Vergata', Rome, Italy,
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Nie X, Li B, Wang S. Epigenetic and Posttranslational Modifications in Regulating the Biology of Aspergillus Species. ADVANCES IN APPLIED MICROBIOLOGY 2018; 105:191-226. [PMID: 30342722 DOI: 10.1016/bs.aambs.2018.05.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Epigenetic and posttranslational modifications have been proved to participate in multiple cellular processes and suggested to be an important regulatory mechanism on transcription of genes in eukaryotes. However, our knowledge about epigenetic and posttranslational modifications mainly comes from the studies of yeasts, plants, and animals. Recently, epigenetic and posttranslational modifications have also raised concern for the relevance of regulating fungal biology in Aspergillus. Emerging evidence indicates that these modifications could be a connection between genetic elements and environmental factors, and their combined effects may finally lead to fungal phenotypical changes. This article describes the advances in typical DNA and protein modifications in the genus Aspergillus, focusing on methylation, acetylation, phosphorylation, ubiquitination, sumoylation, and neddylation.
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Affiliation(s)
- Xinyi Nie
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Bowen Li
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China; State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, China
| | - Shihua Wang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
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Martinez-Rossi NM, Bitencourt TA, Peres NTA, Lang EAS, Gomes EV, Quaresemin NR, Martins MP, Lopes L, Rossi A. Dermatophyte Resistance to Antifungal Drugs: Mechanisms and Prospectus. Front Microbiol 2018; 9:1108. [PMID: 29896175 PMCID: PMC5986900 DOI: 10.3389/fmicb.2018.01108] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 05/09/2018] [Indexed: 12/24/2022] Open
Abstract
Dermatophytes comprise pathogenic fungi that have a high affinity for the keratinized structures present in nails, skin, and hair, causing superficial infections known as dermatophytosis. A reasonable number of antifungal drugs currently exist on the pharmaceutical market to control mycoses; however, their cellular targets are restricted, and fungi may exhibit tolerance or resistance to these agents. For example, the stress caused by antifungal and cytotoxic drugs in sub-inhibitory concentrations promotes compensatory stress responses, with the over-expression of genes involved in cellular detoxification, drug efflux, and signaling pathways being among the various mechanisms that may contribute to drug tolerance. In addition, the ATP-binding cassette transporters in dermatophytes that are responsible for cellular efflux can act synergistically, allowing one to compensate for the absence of the other, revealing the complexity of drug tolerance phenomena. Moreover, mutations in genes coding for target enzymes could lead to substitutions in amino acids involved in the binding of antifungal agents, hindering their performance and leading to treatment failure. The relevance of each one of these mechanisms of resistance to fungal survival is hard to define, mainly because they can act simultaneously in the cell. However, an understanding of the molecular mechanisms involved in the resistance/tolerance processes, the identification of new antifungal targets, as well as the prospective of new antifungal compounds among natural or synthetic products, are expected to bring advances and new insights that facilitate the improvement or development of novel strategies for antifungal therapy.
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Affiliation(s)
- Nilce M Martinez-Rossi
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Tamires A Bitencourt
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Nalu T A Peres
- Department of Morphology, Federal University of Sergipe, Aracaju, Brazil
| | - Elza A S Lang
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Eriston V Gomes
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Natalia R Quaresemin
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Maíra P Martins
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Lucia Lopes
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Antonio Rossi
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
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Mount HO, Revie NM, Todd RT, Anstett K, Collins C, Costanzo M, Boone C, Robbins N, Selmecki A, Cowen LE. Global analysis of genetic circuitry and adaptive mechanisms enabling resistance to the azole antifungal drugs. PLoS Genet 2018; 14:e1007319. [PMID: 29702647 PMCID: PMC5922528 DOI: 10.1371/journal.pgen.1007319] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 03/19/2018] [Indexed: 12/20/2022] Open
Abstract
Invasive fungal infections caused by the pathogen Candida albicans have transitioned from a rare curiosity to a major cause of human mortality. This is in part due to the emergence of resistance to the limited number of antifungals available to treat fungal infections. Azoles function by targeting the biosynthesis of ergosterol, a key component of the fungal cell membrane. Loss-of-function mutations in the ergosterol biosynthetic gene ERG3 mitigate azole toxicity and enable resistance that depends upon fungal stress responses. Here, we performed a genome-wide synthetic genetic array screen in Saccharomyces cerevisiae to map ERG3 genetic interactors and uncover novel circuitry important for azole resistance. We identified nine genes that enabled erg3-mediated azole resistance in the model yeast and found that only two of these genes had a conserved impact on resistance in C. albicans. Further, we screened a C. albicans homozygous deletion mutant library and identified 13 genes for which deletion enhances azole susceptibility. Two of the genes, RGD1 and PEP8, were also important for azole resistance acquired by diverse mechanisms. We discovered that loss of function of retrograde transport protein Pep8 overwhelms the functional capacity of the stress response regulator calcineurin, thereby abrogating azole resistance. To identify the mechanism through which the GTPase activator protein Rgd1 enables azole resistance, we selected for mutations that restore resistance in strains lacking Rgd1. Whole genome sequencing uncovered parallel adaptive mechanisms involving amplification of both chromosome 7 and a large segment of chromosome 3. Overexpression of a transporter gene on the right portion of chromosome 3, NPR2, was sufficient to enable azole resistance in the absence of Rgd1. Thus, we establish a novel mechanism of adaptation to drug-induced stress, define genetic circuitry underpinning azole resistance, and illustrate divergence in resistance circuitry over evolutionary time. Fungal infections caused by the pathogen Candida albicans pose a serious threat to human health. Treating these infections relies heavily on the azole antifungals, however, resistance to these drugs develops readily demanding novel therapeutic strategies. We performed large-scale systematic screens in both C. albicans and the model yeast Saccharomyces cerevisiae to identify genes that enable azole resistance. Our genome-wide screen in S. cerevisiae identified nine determinants of azole resistance, only two of which were important for resistance in C. albicans. Our screen of C. albicans mutants identified 13 genes for which deletion enhances susceptibility to azoles, including RGD1 and PEP8. We found that loss of Pep8 overwhelms the functional capacity of a key stress response regulator, calcineurin. In contrast, amplification of chromosome 7 and the right portion of chromosome 3 can restore resistance in strains lacking Rgd1, suggesting that Rgd1 may enable azole resistance by inducing genes in these amplified regions. Specifically, overexpression of a gene involved in transport on chromosome 3, NPR2, was sufficient to restore azole resistance in the absence of Rgd1. Thus, we establish novel circuitry important for antifungal drug resistance, and uncover adaptive mechanisms involving genomic plasticity that occur in response to drug induced stress.
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Affiliation(s)
| | - Nicole M. Revie
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Robert T. Todd
- Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, Nebraska, United States of America
| | - Kaitlin Anstett
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Cathy Collins
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Michael Costanzo
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Charles Boone
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Anna Selmecki
- Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, Nebraska, United States of America
| | - Leah E. Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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49
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Desoubeaux G, Cray C. Animal Models of Aspergillosis. Comp Med 2018; 68:109-123. [PMID: 29663936 PMCID: PMC5897967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 03/29/2017] [Accepted: 07/09/2017] [Indexed: 06/08/2023]
Abstract
Aspergillosis is an airborne fungal disease caused by Aspergillus spp., a group of ubiquitous molds. This disease causes high morbidity and mortality in both humans and animals. The growing importance of this infection over recent decades has created a need for practical and reproducible models of aspergillosis. The use of laboratory animals provides a platform to understand fungal virulence and pathophysiology, assess diagnostic tools, and evaluate new antifungal drugs. In this review, we describe the fungus, various Aspergillus-related diseases in humans and animals and various experimental animal models. Overall, we highlight the advantages and limitations of the animal models, the experimental variables that can affect the course of the disease and the reproducibility of infection, and the critical need for standardization of the species, immunosuppressive drugs, route of infection, and diagnostic criteria to use.
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Affiliation(s)
- Guillaume Desoubeaux
- Department of Pathology and Laboratory Medicine, Division of Comparative Pathology, Miller School of Medicine, University of Miami, Miami, Florida, USA; Parasitology-Mycology Service, Tropical Medicine Program, University Hospital of Tours, CEPR - Inserm U1100, Medical Faculty, François Rabelais University, Tours, France
| | - Carolyn Cray
- Department of Pathology and Laboratory Medicine, Division of Comparative Pathology, Miller School of Medicine, University of Miami, Miami, Florida, USA.,
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Renshaw H, Vargas-Muñiz JM, Juvvadi PR, Richards AD, Waitt G, Soderblom EJ, Moseley MA, Steinbach WJ. The tail domain of the Aspergillus fumigatus class V myosin MyoE orchestrates septal localization and hyphal growth. J Cell Sci 2018; 131:jcs.205955. [PMID: 29222113 DOI: 10.1242/jcs.205955] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Accepted: 12/05/2017] [Indexed: 01/10/2023] Open
Abstract
Myosins are critical motor proteins that contribute to the secretory pathway, polarized growth, and cytokinesis. The globular tail domains of class V myosins have been shown to be important for cargo binding and actin cable organization. Additionally, phosphorylation plays a role in class V myosin cargo choice. Our previous studies on the class V myosin MyoE in the fungal pathogen Aspergillus fumigatus confirmed its requirement for normal morphology and virulence. However, the domains and molecular mechanisms governing the functions of MyoE remain unknown. Here, by analyzing tail mutants, we demonstrate that the tail is required for radial growth, conidiation, septation frequency and MyoE's location at the septum. Furthermore, MyoE is phosphorylated at multiple residues in vivo; however, alanine substitution mutants revealed that no single phosphorylated residue was critical. Importantly, in the absence of the phosphatase calcineurin, an additional residue was phosphorylated in its tail domain. Mutation of this tail residue led to mislocalization of MyoE from the septa. This work reveals the importance of the MyoE tail domain and its phosphorylation/dephosphorylation in the growth and morphology of A. fumigatus.
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Affiliation(s)
- Hilary Renshaw
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - José M Vargas-Muñiz
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Praveen R Juvvadi
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, NC 27710, USA
| | - Amber D Richards
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, NC 27710, USA
| | - Greg Waitt
- Duke Proteomics and Metabolomics Core Facility, Center for Genomic and Computational Biology, Duke University, Durham, NC 27708, USA
| | - Erik J Soderblom
- Duke Proteomics and Metabolomics Core Facility, Center for Genomic and Computational Biology, Duke University, Durham, NC 27708, USA
| | - M Arthur Moseley
- Duke Proteomics and Metabolomics Core Facility, Center for Genomic and Computational Biology, Duke University, Durham, NC 27708, USA
| | - William J Steinbach
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA .,Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, NC 27710, USA
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