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Smith-Peavler E, Sircy LM, Nelson DE, McClelland EE. Two Methods of Measuring Cryptococcus neoformans Fungal Burden in Macrophages. Methods Mol Biol 2024; 2775:211-221. [PMID: 38758320 DOI: 10.1007/978-1-0716-3722-7_14] [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: 05/18/2024]
Abstract
The ability of C. neoformans to survive and replicate within host phagocytes enables it to evade the immune system and allows for persistence of the infection. As such, measuring fungal burden of C. neoformans strains-and indeed how drug treatments can influence fungal burden-provides important information about C. neoformans pathogenesis. In this chapter, we describe two methods that may be used to appraise fungal burden: a standard end-point colony-formation assay for calculating the average number of yeast per host cell and a fluorescence microscopy-based method that may be used to measure changes in fungal burden in individual living macrophages in real time.
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Affiliation(s)
- Emily Smith-Peavler
- Department of Biology, Middle Tennessee State University, Murfreesboro, TN, USA
- KIPP Collegiate High School, Nashville, TN, USA
| | - Linda M Sircy
- Department of Biology, Middle Tennessee State University, Murfreesboro, TN, USA
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Salt Lake City, UT, USA
| | - David E Nelson
- Department of Biology, Middle Tennessee State University, Murfreesboro, TN, USA
| | - Erin E McClelland
- Department of Biomedical Sciences, Marian University College of Osteopathic Medicine, Indianapolis, IN, USA.
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2
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Kim S, Lee R, Jeon H, Lee N, Park J, Moon H, Shin J, Min K, Kim JE, Yang JW, Son H. Identification of Essential Genes for the Establishment of Spray-Induced Gene Silencing-Based Disease Control in Fusarium graminearum. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:19302-19311. [PMID: 38018120 DOI: 10.1021/acs.jafc.3c04557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2023]
Abstract
As resistance to chemical fungicides continues to increase inFusarium graminearum, there is a growing need to develop novel disease control strategies. To discover essential genes that could serve as new disease control targets, we selected essential gene candidates that had failed to be deleted in previous studies. Thirteen genes were confirmed to be essential, either by constructing conditional promoter replacement mutants or by employing a clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9 (Cas9)-mediated editing strategy. We synthesized double-stranded RNAs (dsRNAs) targeting these essential genes and analyzed their protective effects in plants using a spray-induced gene silencing (SIGS) method. When dsRNAs targeting Fg10360, Fg13150, and Fg06123 were applied to detached barley leaves prior to fungal inoculation, disease lesions were greatly reduced. Our findings provide evidence of the potential of essential genes identified by a SIGS method to be effective targets for the control of fungal diseases.
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Affiliation(s)
- Sieun Kim
- Department of Agricultural Biotechnology, Seoul National University, Seoul 08826, Republic of Korea
| | - Rowoon Lee
- Department of Agricultural Biotechnology, Seoul National University, Seoul 08826, Republic of Korea
| | - Hosung Jeon
- Department of Agricultural Biotechnology, Seoul National University, Seoul 08826, Republic of Korea
| | - Nahyun Lee
- Department of Agricultural Biotechnology, Seoul National University, Seoul 08826, Republic of Korea
| | - Jiyeun Park
- Department of Agricultural Biotechnology, Seoul National University, Seoul 08826, Republic of Korea
| | - Heeji Moon
- Department of Agricultural Biotechnology, Seoul National University, Seoul 08826, Republic of Korea
| | - Jiyoung Shin
- Division of Bioresources Bank, Honam National Institute of Biological Resources, Mokpo 58762, Republic of Korea
| | - Kyunghun Min
- Department of Agricultural Biotechnology, Seoul National University, Seoul 08826, Republic of Korea
| | - Jung-Eun Kim
- Research Institute of Climate Change and Agriculture, National Institute of Horticultural and Herbal Science, Jeju 63240, Republic of Korea
| | - Jung-Wook Yang
- Crop Cultivation and Environment Research Division, National Institute of Crop Science, Rural Development Administration, Suwon 16429, Republic of Korea
| | - Hokyoung Son
- Department of Agricultural Biotechnology, Seoul National University, Seoul 08826, Republic of Korea
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea
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3
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Krishnan S, Gupta K, Sivaraman S, Venkatachalam P, Yennamalli RM, Shanmugam SR. Waste to drugs: identification of pyrolysis by-products as antifungal agents against Cryptococcus neoformans. J Biomol Struct Dyn 2023; 41:15386-15399. [PMID: 36927454 DOI: 10.1080/07391102.2023.2188960] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 02/28/2023] [Indexed: 03/18/2023]
Abstract
The fungi, Cryptococcus neoformans cause major infections such as cryptococcal meningitis and cryptococcosis. Therefore, we explored the use of Thioredoxin reductase (Trr1) from C. neoformans as a gene target for the development of novel antifungal agents. Trr1 plays an essential role in the survival in the oxidative environment of macrophages and is important for the virulence of C. neoformans. During the thermochemical conversion (pyrolysis) of lignocellulosic biomass (LCB), a cocktail of compounds is produced by the decomposition and degradation. In general, LCB-derived cocktail of compounds is a rich source of aromatic compounds that have been shown to be antifungal in nature. Usually, the aqueous phase produced during biomass pyrolysis is generally regarded as waste. Here, we used Parthenium hysterophorus biomass as the antifungal source and obtained the aqueous phase after pyrolysis. Using GC-MS analysis of the aqueous phase collected from P. hysterophorus biomass revealed the presence of a large number of aromatic and organic compounds. Using virtual screening, the compounds present in the aqueous phase were docked against Trr1 using GLIDE. Two promising candidates were analyzed further by performing molecular dynamics simulation using GROMACS, to establish stable interactions. We validated the computational results with clustering analysis. We report that 2,4-Di-tertbutyl phenol and 1H-Pyrazole, 4-ethyl-3,5-dimethyl have a potent antifungal property and we postulate that they could be a potent antifungal agent against Trr1 of C. neoformans.
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Affiliation(s)
- Srividhya Krishnan
- Department of Biotechnology, School of Chemical & Biotechnology, SASTRA Deemed University, Thanjavur, India
- Centre for Bioenergy, SASTRA Deemed University, Thanjavur, India
| | - Krishnakant Gupta
- Department of Bioinformatics, School of Chemical & Biotechnology, SASTRA Deemed University, Thanjavur, India
| | - Subramaniyasharma Sivaraman
- Department of Biotechnology, School of Chemical & Biotechnology, SASTRA Deemed University, Thanjavur, India
- Centre for Bioenergy, SASTRA Deemed University, Thanjavur, India
| | - Ponnusami Venkatachalam
- Department of Biotechnology, School of Chemical & Biotechnology, SASTRA Deemed University, Thanjavur, India
- Centre for Bioenergy, SASTRA Deemed University, Thanjavur, India
| | - Ragothaman M Yennamalli
- Department of Bioinformatics, School of Chemical & Biotechnology, SASTRA Deemed University, Thanjavur, India
| | - Saravanan Ramiah Shanmugam
- Department of Biotechnology, School of Chemical & Biotechnology, SASTRA Deemed University, Thanjavur, India
- Centre for Bioenergy, SASTRA Deemed University, Thanjavur, India
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Fu C, Beattie SR, Jezewski AJ, Robbins N, Whitesell L, Krysan DJ, Cowen LE. Genetic analysis of Hsp90 function in Cryptococcus neoformans highlights key roles in stress tolerance and virulence. Genetics 2022; 220:iyab164. [PMID: 34849848 PMCID: PMC8733452 DOI: 10.1093/genetics/iyab164] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 09/27/2021] [Indexed: 11/13/2022] Open
Abstract
The opportunistic human fungal pathogen Cryptococcus neoformans has tremendous impact on global health, causing 181,000 deaths annually. Current treatment options are limited, and the frequent development of drug resistance exacerbates the challenge of managing invasive cryptococcal infections. In diverse fungal pathogens, the essential molecular chaperone Hsp90 governs fungal survival, drug resistance, and virulence. Therefore, targeting this chaperone has emerged as a promising approach to combat fungal infections. However, the role of Hsp90 in supporting C. neoformans pathogenesis remains largely elusive due to a lack of genetic characterization. To help dissect the functions of Hsp90 in C. neoformans, we generated a conditional expression strain in which HSP90 is under control of the copper-repressible promoter CTR4-2. Addition of copper to culture medium depleted Hsp90 transcript and protein levels in this strain, resulting in compromised fungal growth at host temperature; increased sensitivity to stressors, including the azole class of antifungals; altered C. neoformans morphology; and impaired melanin production. Finally, leveraging the fact that copper concentrations vary widely in different mouse tissues, we demonstrated attenuated virulence for the CTR4-2p-HSP90 mutant specifically in an inhalation model of Cryptococcus infection. During invasion and establishment of infection in this mouse model, the pathogen is exposed to the relatively high copper concentrations found in the lung as compared to blood. Overall, this work generates a tractable genetic system to study the role of Hsp90 in supporting the pathogenicity of C. neoformans and provides proof-of-principle that targeting Hsp90 holds great promise as a strategy to control cryptococcal infection.
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Affiliation(s)
- Ci Fu
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Sarah R Beattie
- Departments of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Andrew J Jezewski
- Departments of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Luke Whitesell
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Damian J Krysan
- Departments of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Microbiology/Immunology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
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Impairment of carotenoid biosynthesis through CAR1 gene mutation results in CoQ 10, sterols, and phytoene accumulation in Rhodotorula mucilaginosa. Appl Microbiol Biotechnol 2021; 106:317-327. [PMID: 34910239 DOI: 10.1007/s00253-021-11673-5] [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: 08/11/2021] [Revised: 10/26/2021] [Accepted: 10/28/2021] [Indexed: 10/19/2022]
Abstract
Red yeasts, mainly included in the genera Rhodotorula, Rhodosporidiobolus, and Sporobolomyces, are renowned biocatalysts for the production of a wide range of secondary metabolites of commercial interest, among which lipids, carotenoids, and other isoprenoids. The production of all these compounds is tightly interrelated as they share acetyl-CoA and the mevalonate pathway as common intermediates. Here, T-DNA insertional mutagenesis was applied to the wild type strain C2.5t1 of Rhodotorula mucilaginosa for the isolation of albino mutants with impaired carotenoids biosynthesis. The rationale behind this approach was that a blockage in carotenoid biosynthetic pathway could divert carbon flux toward the production of lipids and/or other molecules deriving from terpenoid precursors. One characterized albino mutant, namely, strain W4, carries a T-DNA insertion in the CAR1 gene coding for phytoene desaturase. When cultured in glycerol-containing medium, W4 strain showed significant decreases in cell density and fatty acids content in respect to the wild type strain. Conversely, it reached significantly higher productions of phytoene, CoQ10, and sterols. These were supported by an increased expression of CAR2 gene that codes for phytoene synthase/lycopene cyclase. Thus, in accordance with the starting hypothesis, the impairment of carotenoids biosynthesis can be explored to pursue the biotechnological exploitation of red yeasts for enhanced production of secondary metabolites with several commercial applications. KEY POINTS: • The production of lipids, carotenoids, and other isoprenoids is tightly interrelated. • CAR1 gene mutation results in the overproduction of phytoene, CoQ10, and sterols. • Albino mutants are promising tools for the production of secondary metabolites.
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Campos TL, Korhonen PK, Hofmann A, Gasser RB, Young ND. Harnessing model organism genomics to underpin the machine learning-based prediction of essential genes in eukaryotes - Biotechnological implications. Biotechnol Adv 2021; 54:107822. [PMID: 34461202 DOI: 10.1016/j.biotechadv.2021.107822] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 08/17/2021] [Accepted: 08/24/2021] [Indexed: 12/17/2022]
Abstract
The availability of high-quality genomes and advances in functional genomics have enabled large-scale studies of essential genes in model eukaryotes, including the 'elegant worm' (Caenorhabditis elegans; Nematoda) and the 'vinegar fly' (Drosophila melanogaster; Arthropoda). However, this is not the case for other, much less-studied organisms, such as socioeconomically important parasites, for which functional genomic platforms usually do not exist. Thus, there is a need to develop innovative techniques or approaches for the prediction, identification and investigation of essential genes. A key approach that could enable the prediction of such genes is machine learning (ML). Here, we undertake an historical review of experimental and computational approaches employed for the characterisation of essential genes in eukaryotes, with a particular focus on model ecdysozoans (C. elegans and D. melanogaster), and discuss the possible applicability of ML-approaches to organisms such as socioeconomically important parasites. We highlight some recent results showing that high-performance ML, combined with feature engineering, allows a reliable prediction of essential genes from extensive, publicly available 'omic data sets, with major potential to prioritise such genes (with statistical confidence) for subsequent functional genomic validation. These findings could 'open the door' to fundamental and applied research areas. Evidence of some commonality in the essential gene-complement between these two organisms indicates that an ML-engineering approach could find broader applicability to ecdysozoans such as parasitic nematodes or arthropods, provided that suitably large and informative data sets become/are available for proper feature engineering, and for the robust training and validation of algorithms. This area warrants detailed exploration to, for example, facilitate the identification and characterisation of essential molecules as novel targets for drugs and vaccines against parasitic diseases. This focus is particularly important, given the substantial impact that such diseases have worldwide, and the current challenges associated with their prevention and control and with drug resistance in parasite populations.
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Affiliation(s)
- Tulio L Campos
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria 3010, Australia; Bioinformatics Core Facility, Instituto Aggeu Magalhães, Fundação Oswaldo Cruz (IAM-Fiocruz), Recife, Pernambuco, Brazil
| | - Pasi K Korhonen
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Andreas Hofmann
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Robin B Gasser
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Neil D Young
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria 3010, Australia.
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Felix L, Mylonakis E, Fuchs BB. Thioredoxin Reductase Is a Valid Target for Antimicrobial Therapeutic Development Against Gram-Positive Bacteria. Front Microbiol 2021; 12:663481. [PMID: 33936021 PMCID: PMC8085250 DOI: 10.3389/fmicb.2021.663481] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 03/29/2021] [Indexed: 12/13/2022] Open
Abstract
There is a drought of new antibacterial compounds that exploit novel targets. Thioredoxin reductase (TrxR) from the Gram-positive bacterial antioxidant thioredoxin system has emerged from multiple screening efforts as a potential target for auranofin, ebselen, shikonin, and allicin. Auranofin serves as the most encouraging proof of concept drug, demonstrating TrxR inhibition can result in bactericidal effects and inhibit Gram-positive bacteria in both planktonic and biofilm states. Minimal inhibitory concentrations are on par or lower than gold standard medications, even among drug resistant isolates. Importantly, existing drug resistance mechanisms that challenge treatment of infections like Staphylococcus aureus do not confer resistance to TrxR targeting compounds. The observed inhibition by multiple compounds and inability to generate a bacterial genetic mutant demonstrate TrxR appears to play an essential role in Gram-positive bacteria. These findings suggest TrxR can be exploited further for drug development. Examining the interaction between TrxR and these proof of concept compounds illustrates that compounds representing a new antimicrobial class can be developed to directly interact and inhibit the validated target.
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Affiliation(s)
- LewisOscar Felix
- Division of Infectious Diseases, Rhode Island Hospital, Alpert Medical School and Brown University, Providence, RI, United States
| | - Eleftherios Mylonakis
- Division of Infectious Diseases, Rhode Island Hospital, Alpert Medical School and Brown University, Providence, RI, United States
| | - Beth Burgwyn Fuchs
- Division of Infectious Diseases, Rhode Island Hospital, Alpert Medical School and Brown University, Providence, RI, United States
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Molecular Tools for the Yeast Papiliotrema terrestris LS28 and Identification of Yap1 as a Transcription Factor Involved in Biocontrol Activity. Appl Environ Microbiol 2021; 87:AEM.02910-20. [PMID: 33452020 DOI: 10.1128/aem.02910-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 01/01/2021] [Indexed: 01/19/2023] Open
Abstract
Fungal attacks on stored fruit and vegetables are responsible for losses of products. There is an active research field to develop alternative strategies for postharvest disease management, and the use of biocontrol agents represents a promising approach. Understanding the molecular bases of the biocontrol activity of these agents is crucial to potentiate their effectiveness. The yeast Papiliotrema terrestris is a biocontrol agent against postharvest pathogens. Phenotypic studies suggest that it exerts its antagonistic activity through competition for nutrients and space, which relies on its resistance to oxidative and other cellular stresses. In this study, we developed tools for genetic manipulation in P. terrestris to perform targeted gene replacement and functional complementation of the transcription factors Yap1 and Rim101. In vitro phenotypic analyses revealed a conserved role of Yap1 and Rim101 in broad resistance to oxidative stress and alkaline pH sensing, respectively. In vivo analyses revealed that P. terrestris yap1Δ and rim101Δ mutants display decreased ability to colonize wounded fruit compared to that of the parental wild-type (WT) strain; the yap1Δ mutant also displays reduced biocontrol activity against the postharvest pathogens Penicillium expansum and Monilinia fructigena, indicating an important role for resistance to oxidative stress in timely wound colonization and biocontrol activity of P. terrestris In conclusion, the availability of molecular tools developed in the present study provides a foundation to elucidate the genetic mechanisms underlying biocontrol activity of P. terrestris, with the goal of enhancing this activity for the practical use of P. terrestris in pest management programs based on biological and integrated control.IMPORTANCE The use of fungicides represents the most effective and widely used strategy for controlling postharvest diseases. However, their extensive use has raised several concerns, such as the emergence of plant pathogens' resistance as well as the health risks associated with the persistence of chemical residues in fruit, in vegetables, and in the environment. These factors have brought attention to alternative methods for controlling postharvest diseases, such as the utilization of biocontrol agents. In the present study, we developed genetic resources to investigate at the molecular level the mechanisms involved in the biocontrol activity of Papiliotrema terrestris, a basidiomycete yeast that is an effective biocontrol agent against widespread fungal pathogens, including Penicillium expansum, the etiological agent of blue mold disease of pome fruits. A deeper understanding of how postharvest biocontrol agents operate is the basic requirement to promote the utilization of biological (and integrated) control for the reduction of chemical fungicides.
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Lee S, Nam M, Lee AR, Lee J, Woo J, Kang NS, Balupuri A, Lee M, Kim SY, Ro H, Choi YW, Kim DU, Hoe KL. Systematic Target Screening Revealed That Tif302 Could Be an Off-Target of the Antifungal Terbinafine in Fission Yeast. Biomol Ther (Seoul) 2021; 29:234-247. [PMID: 33223513 PMCID: PMC7921855 DOI: 10.4062/biomolther.2020.166] [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: 09/25/2020] [Revised: 10/12/2020] [Accepted: 10/13/2020] [Indexed: 11/22/2022] Open
Abstract
We used a heterozygous gene deletion library of fission yeasts comprising all essential and non-essential genes for a microarray screening of target genes of the antifungal terbinafine, which inhibits ergosterol synthesis via the Erg1 enzyme. We identified 14 heterozygous strains corresponding to 10 non-essential [7 ribosomal-protein (RP) coding genes, spt7, spt20, and elp2] and 4 essential genes (tif302, rpl2501, rpl31, and erg1). Expectedly, their erg1 mRNA and protein levels had decreased compared to the control strain SP286. When we studied the action mechanism of the non-essential target genes using cognate haploid deletion strains, knockout of SAGA-subunit genes caused a down-regulation in erg1 transcription compared to the control strain ED668. However, knockout of RP genes conferred no susceptibility to ergosterol-targeting antifungals. Surprisingly, the RP genes participated in the erg1 transcription as components of repressor complexes as observed in a comparison analysis of the experimental ratio of erg1 mRNA. To understand the action mechanism of the interaction between the drug and the novel essential target genes, we performed isobologram assays with terbinafine and econazole (or cycloheximide). Terbinafine susceptibility of the tif302 heterozygous strain was attributed to both decreased erg1 mRNA levels and inhibition of translation. Moreover, Tif302 was required for efficacy of both terbinafine and cycloheximide. Based on a molecular modeling analysis, terbinafine could directly bind to Tif302 in yeasts, suggesting Tif302 as a potential off-target of terbinafine. In conclusion, this genome-wide screening system can be harnessed for the identification and characterization of target genes under any condition of interest.
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Affiliation(s)
- Sol Lee
- Department of New Drug Development, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Miyoung Nam
- Department of New Drug Development, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Ah-Reum Lee
- Department of New Drug Development, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Jaewoong Lee
- Department of New Drug Development, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Jihye Woo
- Department of New Drug Development, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Nam Sook Kang
- Department of New Drug Development, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Anand Balupuri
- Department of New Drug Development, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Minho Lee
- Department of Life Science, Dongguk University-Seoul, Goyang 10326, Republic of Korea
| | - Seon-Young Kim
- Personalized Genomic Research Center, Korea Research Institute of Bioscience & Biotechnology (KRIBB), Daejeon 34141, Republic of Korea
| | - Hyunju Ro
- Department of Biological Science, College of Bioscience & Biotechnology, Chungnam National University, Daejeon 34134, Republic of Korea
| | | | - Dong-Uk Kim
- Rare Disease Research Center, Korea Research Institute of Bioscience & Biotechnology (KRIBB), Daejeon 34141, Republic of Korea
| | - Kwang-Lae Hoe
- Department of New Drug Development, Chungnam National University, Daejeon 34134, Republic of Korea
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Seki Kioshima E, de Souza Bonfim de Mendonça P, de Melo Teixeira M, Grenier Capoci IR, Amaral A, Vilugron Rodrigues-Vendramini FA, Lauton Simões B, Rodrigues Abadio AK, Fernandes Matos L, Soares Felipe MS. One Century of Study: What We Learned about Paracoccidioides and How This Pathogen Contributed to Advances in Antifungal Therapy. J Fungi (Basel) 2021; 7:106. [PMID: 33540749 PMCID: PMC7913102 DOI: 10.3390/jof7020106] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 01/19/2021] [Accepted: 01/26/2021] [Indexed: 02/08/2023] Open
Abstract
Paracoccidioidomycosis (PCM) is a notable fungal infection restricted to Latin America. Since the first description of the disease by Lutz up to the present day, Brazilian researchers have contributed to the understanding of the life cycle of this pathogen and provided the possibility of new targets for antifungal therapy based on the structural and functional genomics of Paracoccidioides. In this context, in silico approaches have selected molecules that act on specific targets, such as the thioredoxin system, with promising antifungal activity against Paracoccidioides. Some of these are already in advanced development stages. In addition, the application of nanostructured systems has addressed issues related to the high toxicity of conventional PCM therapy. Thus, the contribution of molecular biology and biotechnology to the advances achieved is unquestionable. However, it is still necessary to transcend the boundaries of synthetic chemistry, pharmaco-technics, and pharmacodynamics, aiming to turn promising molecules into newly available drugs for the treatment of fungal diseases.
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Affiliation(s)
- Erika Seki Kioshima
- Program in Biosciences and Pathophysiology, Department of Clinical Analysis and Biomedicine, State University of Maringa (UEM), Maringa, Parana 87020-900, Brazil; (P.d.S.B.d.M.); (I.R.G.C.); (F.A.V.R.-V.); (B.L.S.)
| | - Patrícia de Souza Bonfim de Mendonça
- Program in Biosciences and Pathophysiology, Department of Clinical Analysis and Biomedicine, State University of Maringa (UEM), Maringa, Parana 87020-900, Brazil; (P.d.S.B.d.M.); (I.R.G.C.); (F.A.V.R.-V.); (B.L.S.)
| | - Marcus de Melo Teixeira
- Faculty of Medicine, University of Brasília (UnB), Brasilia, Distrito Federal 70910-900, Brazil;
| | - Isis Regina Grenier Capoci
- Program in Biosciences and Pathophysiology, Department of Clinical Analysis and Biomedicine, State University of Maringa (UEM), Maringa, Parana 87020-900, Brazil; (P.d.S.B.d.M.); (I.R.G.C.); (F.A.V.R.-V.); (B.L.S.)
| | - André Amaral
- Institute of Tropical Pathology and Public Health, Federal University of Goiás, Goiânia 74690-900, Brazil;
| | - Franciele Abigail Vilugron Rodrigues-Vendramini
- Program in Biosciences and Pathophysiology, Department of Clinical Analysis and Biomedicine, State University of Maringa (UEM), Maringa, Parana 87020-900, Brazil; (P.d.S.B.d.M.); (I.R.G.C.); (F.A.V.R.-V.); (B.L.S.)
| | - Bruna Lauton Simões
- Program in Biosciences and Pathophysiology, Department of Clinical Analysis and Biomedicine, State University of Maringa (UEM), Maringa, Parana 87020-900, Brazil; (P.d.S.B.d.M.); (I.R.G.C.); (F.A.V.R.-V.); (B.L.S.)
| | - Ana Karina Rodrigues Abadio
- Faculty of Agricultural Social Sciences, Mato Grosso State University, Nova Mutum, Mato Grosso 78450-000, Brazil;
| | - Larissa Fernandes Matos
- Faculty of Ceilandia, University of Brasília (UnB), Brasília, Distrito Federal 72220-275, Brazil;
- Program in Microbial Biology, Institute of Biological Sciences, University of Brasília, Brasília 70910-900, Brazil
| | - Maria Sueli Soares Felipe
- Program of Genomic Sciences and Biotechnology, Catholic University of Brasilia, Brasília 70790-160, Brazil;
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11
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Treatment strategies for cryptococcal infection: challenges, advances and future outlook. Nat Rev Microbiol 2021; 19:454-466. [PMID: 33558691 PMCID: PMC7868659 DOI: 10.1038/s41579-021-00511-0] [Citation(s) in RCA: 135] [Impact Index Per Article: 45.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/07/2021] [Indexed: 01/31/2023]
Abstract
Cryptococcus spp., in particular Cryptococcus neoformans and Cryptococcus gattii, have an enormous impact on human health worldwide. The global burden of cryptococcal meningitis is almost a quarter of a million cases and 181,000 deaths annually, with mortality rates of 100% if infections remain untreated. Despite these alarming statistics, treatment options for cryptococcosis remain limited, with only three major classes of drugs approved for clinical use. Exacerbating the public health burden is the fact that the only new class of antifungal drugs developed in decades, the echinocandins, displays negligible antifungal activity against Cryptococcus spp., and the efficacy of the remaining therapeutics is hampered by host toxicity and pathogen resistance. Here, we describe the current arsenal of antifungal agents and the treatment strategies employed to manage cryptococcal disease. We further elaborate on the recent advances in our understanding of the intrinsic and adaptive resistance mechanisms that are utilized by Cryptococcus spp. to evade therapeutic treatments. Finally, we review potential therapeutic strategies, including combination therapy, the targeting of virulence traits, impairing stress response pathways and modulating host immunity, to effectively treat infections caused by Cryptococcus spp. Overall, understanding of the mechanisms that regulate anti-cryptococcal drug resistance, coupled with advances in genomics technologies and high-throughput screening methodologies, will catalyse innovation and accelerate antifungal drug discovery.
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12
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Ianiri G, Heitman J. Approaches for Genetic Discoveries in the Skin Commensal and Pathogenic Malassezia Yeasts. Front Cell Infect Microbiol 2020; 10:393. [PMID: 32850491 PMCID: PMC7426719 DOI: 10.3389/fcimb.2020.00393] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 06/25/2020] [Indexed: 12/21/2022] Open
Abstract
Malassezia includes yeasts belong to the subphylum Ustilaginomycotina within the Basidiomycota. Malassezia yeasts are commonly found as commensals on human and animal skin. Nevertheless, Malassezia species are also associated with several skin disorders, such as dandruff/seborrheic dermatitis, atopic eczema, pityriasis versicolor, and folliculitis. More recently, associations of Malassezia with Crohn's disease, pancreatic ductal adenocarcinoma, and cystic fibrosis pulmonary exacerbation have been reported. The increasing availability of genomic and molecular tools have played a crucial role in understanding the genetic basis of Malassezia commensalism and pathogenicity. In the present review we report genomics advances in Malassezia highlighting unique features that potentially impacted Malassezia biology and host adaptation. Furthermore, we describe the recently developed protocols for Agrobacterium tumefaciens-mediated transformation in Malassezia, and their applications for random insertional mutagenesis or targeted gene replacement strategies.
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Affiliation(s)
- Giuseppe Ianiri
- Department of Agricultural, Environmental and Food Sciences, Università degli Studi del Molise, Campobasso, Italy
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, United States
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13
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Ianiri G, Fang YF, Dahlmann TA, Clancey SA, Janbon G, Kück U, Heitman J. Mating-Type-Specific Ribosomal Proteins Control Aspects of Sexual Reproduction in Cryptococcus neoformans. Genetics 2020; 214:635-649. [PMID: 31882399 PMCID: PMC7054023 DOI: 10.1534/genetics.119.302740] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 12/21/2019] [Indexed: 12/31/2022] Open
Abstract
The MAT locus of Cryptococcus neoformans has a bipolar organization characterized by an unusually large structure, spanning over 100 kb. MAT genes have been characterized by functional genetics as being involved in sexual reproduction and virulence. However, classical gene replacement failed to achieve mutants for five MAT genes (RPL22, RPO41, MYO2, PRT1, and RPL39), indicating that they are likely essential. In the present study, targeted gene replacement was performed in a diploid strain for both the α and a alleles of the ribosomal genes RPL22 and RPL39 Mendelian analysis of the progeny confirmed that both RPL22 and RPL39 are essential for viability. Ectopic integration of the RPL22 allele of opposite MAT identity in the heterozygous RPL22a/rpl22αΔ or RPL22α/rpl22aΔ mutant strains failed to complement their essential phenotype. Evidence suggests that this is due to differential expression of the RPL22 genes, and an RNAi-dependent mechanism that contributes to control RPL22a expression. Furthermore, via CRISPR/Cas9 technology, the RPL22 alleles were exchanged in haploid MATα and MATa strains of C. neoformans These RPL22 exchange strains displayed morphological and genetic defects during bilateral mating. These results contribute to elucidating functions of C. neoformans essential mating type genes that may constitute a type of imprinting system to promote inheritance of nuclei of both mating types.
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Affiliation(s)
- Giuseppe Ianiri
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina 27710
| | - Yufeng Francis Fang
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina 27710
| | - Tim A Dahlmann
- Allgemeine und Molekulare Botanik, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Shelly Applen Clancey
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina 27710
| | - Guilhem Janbon
- Unité Biologie des ARN des Pathogènes Fongiques, Département de Mycologie, Institut Pasteur, 75015 Paris, France
| | - Ulrich Kück
- Allgemeine und Molekulare Botanik, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina 27710
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14
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Kundu D, Pasrija R. The ERMES (Endoplasmic Reticulum and Mitochondria Encounter Structures) mediated functions in fungi. Mitochondrion 2020; 52:89-99. [PMID: 32105794 DOI: 10.1016/j.mito.2020.02.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Revised: 12/21/2019] [Accepted: 02/21/2020] [Indexed: 01/01/2023]
Abstract
Cellular organelles are membrane-bound and provide a microenvironment for specific functions. A mitochondrion is a double membranous and dynamic organelle that undergoes numerous fusion/fission events, which depends on various cellular factors. However, it is still dependent on other organelles and requires both communications as well as the movement of physical metabolites between them. Mitochondria interact with different organelles counting lipid droplets (LD), peroxisomes, vacuoles, endoplasmic reticulum (ER) and plasma membrane (PM), etc. Apart from them, mitochondria maintain multiple interactions with ER including ERMES (Endoplasmic Reticulum and Mitochondria encounter structures). ERMES is actually a multi-protein complex, and imperative in the maintenance of mitochondrial morphology and its functions. Its disruption also compromises phospholipid exchange, drug resistance and pathogenicity. This assembly is reportedly unique to fungal systems and proposed as a target for development of new antifungal. In the light of separate reports across diverse fungal systems, we have summarised the information about its distribution and effect on mitochondrial fitness.
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Affiliation(s)
- Deepika Kundu
- Department of Biochemistry, Maharshi Dayanand University, Rohtak, Haryana, India
| | - Ritu Pasrija
- Department of Biochemistry, Maharshi Dayanand University, Rohtak, Haryana, India.
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15
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Boyce KJ, Cao C, Xue C, Idnurm A. A spontaneous mutation in DNA polymerase POL3 during in vitro passaging causes a hypermutator phenotype in Cryptococcus species. DNA Repair (Amst) 2019; 86:102751. [PMID: 31838381 DOI: 10.1016/j.dnarep.2019.102751] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 11/08/2019] [Accepted: 11/19/2019] [Indexed: 10/25/2022]
Abstract
Passaging of microbes in vitro can lead to the selection of microevolved derivatives with differing properties to their original parent strains. One well characterised instance is the phenotypic differences observed between the series of strains derived from the type strain of the human pathogenic fungus Cryptococcus neoformans. A second case was reported in the close relative Cryptococcus deneoformans, in which a well-studied isolate ATCC 24067 (52D) altered its phenotypic characteristics after in vitro passaging in different laboratories. One of these derivatives, ATCC 24067A, has decreased virulence and also exhibits a hypermutator phenotype, in which the mutation rate is increased compared to wild type. In this study, the molecular basis behind the changes in the lineage of ATCC 24067 was determined by next-generation sequencing of the parent and passaged strain genomes. This analysis resulted in the identification of a point mutation that causes a D270G amino acid substitution within the exonuclease proofreading domain of the DNA polymerase delta subunit encoded by POL3. Complementation with POL3 confirmed that this mutation is responsible for the hypermutator phenotype of this strain. Regeneration of the mutation in C. neoformans, to eliminate the additional mutations present in the ATCC 24067A genetic background, demonstrated that the hypermutator phenotype of the pol3D270G mutant causes rapid microevolution in vitro but does not result in decreased virulence. These findings indicate that mutator strains can emerge in these pathogenic fungi without conferring a fitness cost, but the subsequent rapid accumulation of mutations can be deleterious.
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Affiliation(s)
- Kylie J Boyce
- School of Science, Engineering and Health, RMIT University, Victoria, Australia.
| | - Chengjun Cao
- Public Health Research Institute, Rutgers University, Newark, New Jersey, USA
| | - Chaoyang Xue
- Public Health Research Institute, Rutgers University, Newark, New Jersey, USA
| | - Alexander Idnurm
- School of BioSciences, University of Melbourne, Victoria, Australia.
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16
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Ianiri G, Dagotto G, Sun S, Heitman J. Advancing Functional Genetics Through Agrobacterium-Mediated Insertional Mutagenesis and CRISPR/Cas9 in the Commensal and Pathogenic Yeast Malassezia. Genetics 2019; 212:1163-1179. [PMID: 31243056 PMCID: PMC6707463 DOI: 10.1534/genetics.119.302329] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 06/22/2019] [Indexed: 12/20/2022] Open
Abstract
Malassezia encompasses a monophyletic group of basidiomycetous yeasts naturally found on the skin of humans and other animals. Malassezia species have lost genes for lipid biosynthesis, and are therefore lipid-dependent and difficult to manipulate under laboratory conditions. In this study, we applied a recently-developed Agrobacterium tumefaciens-mediated transformation protocol to perform transfer (T)-DNA random insertional mutagenesis in Malassezia furfur A total of 767 transformants were screened for sensitivity to 10 different stresses, and 19 mutants that exhibited a phenotype different from the wild type were further characterized. The majority of these strains had single T-DNA insertions, which were identified within open reading frames of genes, untranslated regions, and intergenic regions. Some T-DNA insertions generated chromosomal rearrangements while others could not be characterized. To validate the findings of our forward genetic screen, a novel clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system was developed to generate targeted deletion mutants for two genes identified in the screen: CDC55 and PDR10 This system is based on cotransformation of M. furfur mediated by A. tumefaciens, to deliver both a CAS9-gRNA construct that induces double-strand DNA breaks and a gene replacement allele that serves as a homology-directed repair template. Targeted deletion mutants for both CDC55 and PDR10 were readily generated with this method. This study demonstrates the feasibility and reliability of A. tumefaciens-mediated transformation to aid in the identification of gene functions in M. furfur, through both insertional mutagenesis and CRISPR/Cas9-mediated targeted gene deletion.
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Affiliation(s)
- Giuseppe Ianiri
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina 27710
| | - Gabriel Dagotto
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina 27710
| | - Sheng Sun
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina 27710
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina 27710
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17
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So YS, Lee DG, Idnurm A, Ianiri G, Bahn YS. The TOR Pathway Plays Pleiotropic Roles in Growth and Stress Responses of the Fungal Pathogen Cryptococcus neoformans. Genetics 2019; 212:1241-1258. [PMID: 31175227 PMCID: PMC6707454 DOI: 10.1534/genetics.119.302191] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 06/02/2019] [Indexed: 11/18/2022] Open
Abstract
The target of rapamycin (TOR) pathway is an evolutionarily conserved signal transduction system that governs a plethora of eukaryotic biological processes, but its role in Cryptococcus neoformans remains elusive. In this study, we investigated the TOR pathway by functionally characterizing two Tor-like kinases, Tor1 and Tlk1, in C. neoformans We successfully deleted TLK1, but not TOR1TLK1 deletion did not result in any evident in vitro phenotypes, suggesting that Tlk1 is dispensable for the growth of C. neoformans We demonstrated that Tor1, but not Tlk1, is essential and the target of rapamycin by constructing and analyzing conditionally regulated strains and sporulation analysis of heterozygous mutants in the diploid strain background. To further analyze the Tor1 function, we constructed constitutive TOR1 overexpression strains. Tor1 negatively regulated thermotolerance and the DNA damage response, which are two important virulence factors of C. neoformansTOR1 overexpression reduced Mpk1 phosphorylation, which is required for cell wall integrity and thermoresistance, and Rad53 phosphorylation, which governs the DNA damage response pathway. Tor1 is localized to the cytoplasm, but enriched in the vacuole membrane. Phosphoproteomics and transcriptomics revealed that Tor1 regulates a variety of biological processes, including metabolic processes, cytoskeleton organization, ribosome biogenesis, and stress response. TOR inhibition by rapamycin caused actin depolarization in a Tor1-dependent manner. Finally, screening rapamycin-sensitive and -resistant kinase and transcription factor mutants revealed that the TOR pathway may crosstalk with a number of stress signaling pathways. In conclusion, our study demonstrates that a single Tor1 kinase plays pleiotropic roles in C. neoformans.
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Affiliation(s)
- Yee-Seul So
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
| | - Dong-Gi Lee
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
| | - Alexander Idnurm
- School of BioSciences, The University of Melbourne, Victoria 3010, Australia
| | - Giuseppe Ianiri
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina 27710
| | - Yong-Sun Bahn
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
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18
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Staerck C, Tabiasco J, Godon C, Delneste Y, Bouchara JP, Fleury MJJ. Transcriptional profiling of Scedosporium apiospermum enzymatic antioxidant gene battery unravels the involvement of thioredoxin reductases against chemical and phagocytic cells oxidative stress. Med Mycol 2019; 57:363-373. [PMID: 29889264 DOI: 10.1093/mmy/myy033] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 03/22/2018] [Accepted: 05/01/2018] [Indexed: 12/15/2022] Open
Abstract
Scedosporium species rank the second, after Aspergillus fumigatus, among the filamentous fungi colonizing the airways of patients with cystic fibrosis (CF). Development of microorganisms in the respiratory tract depends on their capacity to evade killing by the host immune system, particularly through the oxidative response of macrophages and neutrophils, with the release of reactive oxygen species (ROS) and reactive nitrogen species (RNS). This is particularly true in the airways of CF patients which display an exacerbated inflammatory reaction. To protect themselves, pathogens have developed various enzymatic antioxidant systems implicated in ROS degradation, including superoxide dismutases, catalases, cytochrome C peroxidases, chloroperoxidases and enzymes of the glutathione and thioredoxin systems, or in RNS degradation, that is, flavohemoglobins, nitrate reductases, and nitrite reductases. Here we investigated the transcriptional regulation of the enzymatic antioxidant gene battery in 24-h-old hyphae of Scedosporium apiospermum in response to oxidative stress induced chemically or by exposure to activated phagocytic cells. We showed that 21 out of the 33 genes potentially implicated in the oxidative or nitrosative stress response were overexpressed upon exposure of the fungus to various chemical oxidants, while they were only 13 in co-cultures with macrophages or neutrophils. Among them, genes encoding two thioredoxin reductases and to a lesser extent, a peroxiredoxin and one catalase were found to be overexpressed after chemical oxidative stress as well as in co-cultures. These results suggest that thioredoxin reductases, which are known to be virulence factors in other pathogenic fungi, play a key role in pathogenesis of scedosporiosis, and may be new drug targets.
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Affiliation(s)
- Cindy Staerck
- Groupe d'Etude des Interactions Hôte-Pathogène (EA 3142), UNIV Angers, UNIV Brest, Université Bretagne-Loire, Angers, France
| | - Julie Tabiasco
- CRCINA, INSERM, Université de Nantes, Université d'Angers, Angers, France
| | - Charlotte Godon
- Groupe d'Etude des Interactions Hôte-Pathogène (EA 3142), UNIV Angers, UNIV Brest, Université Bretagne-Loire, Angers, France
| | - Yves Delneste
- CRCINA, INSERM, Université de Nantes, Université d'Angers, Angers, France.,Laboratoire d'Immunologie et Allergologie, Centre Hospitalier Universitaire d'Angers, France
| | - Jean-Philippe Bouchara
- Groupe d'Etude des Interactions Hôte-Pathogène (EA 3142), UNIV Angers, UNIV Brest, Université Bretagne-Loire, Angers, France.,Laboratoire de Parasitologie-Mycologie, Centre Hospitalier Universitaire, Angers, France
| | - Maxime J J Fleury
- Groupe d'Etude des Interactions Hôte-Pathogène (EA 3142), UNIV Angers, UNIV Brest, Université Bretagne-Loire, Angers, France
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19
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Burke JE, Longhurst AD, Merkurjev D, Sales-Lee J, Rao B, Moresco JJ, Yates JR, Li JJ, Madhani HD. Spliceosome Profiling Visualizes Operations of a Dynamic RNP at Nucleotide Resolution. Cell 2019; 173:1014-1030.e17. [PMID: 29727661 DOI: 10.1016/j.cell.2018.03.020] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 01/19/2018] [Accepted: 03/07/2018] [Indexed: 11/28/2022]
Abstract
Tools to understand how the spliceosome functions in vivo have lagged behind advances in the structural biology of the spliceosome. Here, methods are described to globally profile spliceosome-bound pre-mRNA, intermediates, and spliced mRNA at nucleotide resolution. These tools are applied to three yeast species that span 600 million years of evolution. The sensitivity of the approach enables the detection of canonical and non-canonical events, including interrupted, recursive, and nested splicing. This application of statistical modeling uncovers independent roles for the size and position of the intron and the number of introns per transcript in substrate progression through the two catalytic stages. These include species-specific inputs suggestive of spliceosome-transcriptome coevolution. Further investigations reveal the ATP-dependent discard of numerous endogenous substrates after spliceosome assembly in vivo and connect this discard to intron retention, a form of splicing regulation. Spliceosome profiling is a quantitative, generalizable global technology used to investigate an RNP central to eukaryotic gene expression.
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Affiliation(s)
- Jordan E Burke
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Adam D Longhurst
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Daria Merkurjev
- Department of Statistics, University of California, Los Angeles, Los Angeles, CA, USA
| | - Jade Sales-Lee
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Beiduo Rao
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - James J Moresco
- Department of Molecular Medicine, the Scripps Research Institute, La Jolla, CA, USA
| | - John R Yates
- Department of Molecular Medicine, the Scripps Research Institute, La Jolla, CA, USA
| | - Jingyi Jessica Li
- Department of Statistics, University of California, Los Angeles, Los Angeles, CA, USA
| | - Hiten D Madhani
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA; Chan-Zuckerberg Biohub, San Francisco, CA 94158, USA.
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20
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Nicola AM, Albuquerque P, Paes HC, Fernandes L, Costa FF, Kioshima ES, Abadio AKR, Bocca AL, Felipe MS. Antifungal drugs: New insights in research & development. Pharmacol Ther 2018; 195:21-38. [PMID: 30347212 DOI: 10.1016/j.pharmthera.2018.10.008] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The need for better antifungal therapy is commonly accepted in view of the high mortality rates associated with systemic infections, the low number of available antifungal classes, their associated toxicity and the increasing number of infections caused by strains with natural or acquired resistance. The urgency to expand the range of therapeutic options for the treatment of fungal infections has led researchers in recent decades to seek alternative antifungal targets when compared to the conventional ones currently used. Although new potential targets are reported, translating the discoveries from bench to bedside is a long process and most of these drugs fail to reach the patients. In this review, we discuss the development of antifungal drugs focusing on the approach of drug repurposing and the search for novel drugs for classical targets, the most recently described gene targets for drug development, the possibilities of immunotherapy using antibodies, cytokines, therapeutic vaccines and antimicrobial peptides.
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Affiliation(s)
| | - Patrícia Albuquerque
- Faculty of Ceilândia, University of Brasília, Brazil; Graduate Programme in Microbial Biology, University of Brasília, Brazil
| | - Hugo Costa Paes
- Division of Clinical Medicine, University of Brasília Medical School, Brazil
| | - Larissa Fernandes
- Faculty of Ceilândia, University of Brasília, Brazil; Graduate Programme in Microbial Biology, University of Brasília, Brazil
| | - Fabricio F Costa
- Graduate Programme in Genomic Science and Biotechnology, Catholic University of Brasília, Brazil; MATTER, Chicago, IL, USA; Cancer Biology and Epigenomics Program, Ann & Robert Lurie Children's Hospital of Chicago Research Center, Northwestern University's Feinberg School of Medicine, Chicago, Illinois, USA
| | - Erika Seki Kioshima
- Department of Clinical Analysis and Biomedicine, State University of Maringá, Paraná, Brazil
| | - Ana Karina Rodrigues Abadio
- School for Applied Social and Agricultural Sciences, State University of Mato Grosso, Nova Mutum Campus, Mato Grosso, Brazil
| | | | - Maria Sueli Felipe
- Graduate Programme in Genomic Science and Biotechnology, Catholic University of Brasília, Brazil; Department of Cell Biology, Institute of Biological Sciences, University of Brasília, Brazil.
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21
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Kummari LK, Butler MS, Furlong E, Blundell R, Nouwens A, Silva AB, Kappler U, Fraser JA, Kobe B, Cooper MA, Robertson AAB. Antifungal benzo[b]thiophene 1,1-dioxide IMPDH inhibitors exhibit pan-assay interference (PAINS) profiles. Bioorg Med Chem 2018; 26:5408-5419. [PMID: 30322754 DOI: 10.1016/j.bmc.2018.09.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 08/21/2018] [Accepted: 09/03/2018] [Indexed: 12/14/2022]
Abstract
Fungi cause serious life-threatening infections in immunocompromised individuals and current treatments are now complicated by toxicity issues and the emergence of drug resistant strains. Consequently, there is a need for development of new antifungal drugs. Inosine monophosphate dehydrogenase (IMPDH), a key component of the de novo purine biosynthetic pathway, is essential for growth and virulence of fungi and is a potential drug target. In this study, a high-throughput screen of 114,000 drug-like compounds against Cryptococcus neoformans IMPDH was performed. We identified three 3-((5-substituted)-1,3,4-oxadiazol-2-yl)thio benzo[b]thiophene 1,1-dioxides that inhibited Cryptococcus IMPDH and also possessed whole cell antifungal activity. Analogs were synthesized to explore the SAR of these hits. Modification of the fifth substituent on the 1,3,4-oxadiazole ring yielded compounds with nanomolar in vitro activity, but with associated cytotoxicity. In contrast, two analogs generated by substituting the 1,3,4-oxadiazole ring with imidazole and 1,2,4-triazole gave reduced IMPDH inhibition in vitro, but were not cytotoxic. During enzyme kinetic studies in the presence of DTT, nucleophilic attack of a free thiol occurred with the benzo[b]thiophene 1,1-dioxide. Two representative compounds with substitution at the 5 position of the 1,3,4-oxadiazole ring, showed mixed inhibition in the absence of DTT. Incubation of these compounds with Cryptococcus IMPDH followed by mass spectrometry analysis showed non-specific and covalent binding with IMPDH at multiple cysteine residues. These results support recent reports that the benzo[b]thiophene 1,1-dioxides moiety as PAINS (pan-assay interference compounds) contributor.
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Affiliation(s)
- Lalith K Kummari
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland 4072, Australia; Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia; Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Mark S Butler
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Emily Furlong
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Ross Blundell
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Amanda Nouwens
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Alberto B Silva
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia; AC Immune SA, EPFL Innovation Park, CH-1015 Lausanne, Switzerland
| | - Ulrike Kappler
- Centre for Metals in Biology, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - James A Fraser
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Bostjan Kobe
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia; Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Matthew A Cooper
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Avril A B Robertson
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland 4072, Australia; Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia.
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22
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Meir Z, Osherov N. Vitamin Biosynthesis as an Antifungal Target. J Fungi (Basel) 2018; 4:E72. [PMID: 29914189 PMCID: PMC6023522 DOI: 10.3390/jof4020072] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 06/12/2018] [Accepted: 06/13/2018] [Indexed: 12/18/2022] Open
Abstract
The large increase in the population of immunosuppressed patients, coupled with the limited efficacy of existing antifungals and rising resistance toward them, have dramatically highlighted the need to develop novel drugs for the treatment of invasive fungal infections. An attractive possibility is the identification of possible drug targets within essential fungal metabolic pathways not shared with humans. Here, we review the vitamin biosynthetic pathways (vitamins A⁻E, K) as candidates for the development of antifungals. We present a set of ranking criteria that identify the vitamin B2 (riboflavin), B5 (pantothenic acid), and B9 (folate) biosynthesis pathways as being particularly rich in new antifungal targets. We propose that recent scientific advances in the fields of drug design and fungal genomics have developed sufficiently to merit a renewed look at these pathways as promising sources for the development of novel classes of antifungals.
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Affiliation(s)
- Zohar Meir
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel-Aviv University, Ramat-Aviv, Tel-Aviv 69978, Israel.
| | - Nir Osherov
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel-Aviv University, Ramat-Aviv, Tel-Aviv 69978, Israel.
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23
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Motaung TE. Cryptococcus neoformans mutant screening: a genome-scale's worth of function discovery. FUNGAL BIOL REV 2018. [DOI: 10.1016/j.fbr.2018.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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24
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Amino Acid Metabolism and Transport Mechanisms as Potential Antifungal Targets. Int J Mol Sci 2018; 19:ijms19030909. [PMID: 29562716 PMCID: PMC5877770 DOI: 10.3390/ijms19030909] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 03/13/2018] [Accepted: 03/15/2018] [Indexed: 01/15/2023] Open
Abstract
Discovering new drugs for treatment of invasive fungal infections is an enduring challenge. There are only three major classes of antifungal agents, and no new class has been introduced into clinical practice in more than a decade. However, recent advances in our understanding of the fungal life cycle, functional genomics, proteomics, and gene mapping have enabled the identification of new drug targets to treat these potentially deadly infections. In this paper, we examine amino acid transport mechanisms and metabolism as potential drug targets to treat invasive fungal infections, including pathogenic yeasts, such as species of Candida and Cryptococcus, as well as molds, such as Aspergillus fumigatus. We also explore the mechanisms by which amino acids may be exploited to identify novel drug targets and review potential hurdles to bringing this approach into clinical practice.
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25
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Coradetti ST, Pinel D, Geiselman GM, Ito M, Mondo SJ, Reilly MC, Cheng YF, Bauer S, Grigoriev IV, Gladden JM, Simmons BA, Brem RB, Arkin AP, Skerker JM. Functional genomics of lipid metabolism in the oleaginous yeast Rhodosporidium toruloides. eLife 2018. [PMID: 29521624 PMCID: PMC5922974 DOI: 10.7554/elife.32110] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The basidiomycete yeast Rhodosporidium toruloides (also known as Rhodotorula toruloides) accumulates high concentrations of lipids and carotenoids from diverse carbon sources. It has great potential as a model for the cellular biology of lipid droplets and for sustainable chemical production. We developed a method for high-throughput genetics (RB-TDNAseq), using sequence-barcoded Agrobacterium tumefaciens T-DNA insertions. We identified 1,337 putative essential genes with low T-DNA insertion rates. We functionally profiled genes required for fatty acid catabolism and lipid accumulation, validating results with 35 targeted deletion strains. We identified a high-confidence set of 150 genes affecting lipid accumulation, including genes with predicted function in signaling cascades, gene expression, protein modification and vesicular trafficking, autophagy, amino acid synthesis and tRNA modification, and genes of unknown function. These results greatly advance our understanding of lipid metabolism in this oleaginous species and demonstrate a general approach for barcoded mutagenesis that should enable functional genomics in diverse fungi. The fungus Rhodosporidium toruloides can grow on substances extracted from plant matter that is inedible to humans such as corn stalks, wood pulp, and grasses. Under some growth conditions, the fungus can accumulate massive stores of hydrocarbon-rich fats and pigments. A community of scientists and engineers has begun genetically modifying R. toruloides to convert these naturally produced fats and pigments into fuels, chemicals and medicines. These could form sustainable replacements for products made from petroleum or harvested from threatened animal and plant species. Fungi, plants, animals and other eukaryotes store fat in specialized compartments called lipid droplets. The genes that control the metabolism – the production, use and storage – of fat in lipid bodies have been studied in certain eukaryotes, including species of yeast. However, R. toruloides is only distantly related to the most well-studied of these species. This means that we cannot be certain that a gene will play the same role in R. toruloides as in those species. To assemble the most comprehensive list possible of the genes in R. toruloides that affect the production, use, or storage of fat in lipid bodies, Coradetti, Pinel et al. constructed a population of hundreds of thousands of mutant fungal strains, each with its own unique DNA ‘barcode’. The effects that mutations in over 6,000 genes had on growth and fat accumulation in these fungi were measured simultaneously in several experiments. This general approach is not new, but technical limitations had, until now, restricted its use in fungi to a few species. Coradetti, Pinel et al. identified hundreds of genes that affected the ability of R. toruloides to metabolise fat. Many of these genes were related to genes with known roles in fat metabolism in other eukaryotes. Other genes are involved in different cell processes, such as the recycling of waste products in the cell. Their identification adds weight to the view that the links between these cellular processes and fat metabolism are deep and widespread amongst eukaryotes. Finally, some of the genes identified by Coradetti, Pinel et al. are not closely related to any well-studied genes. Further study of these genes could help us to understand why R. toruloides can accumulate much larger amounts of fat than most other fungi. The methods developed by Coradetti, Pinel et al. should be possible to implement in many species of fungi. As a result these techniques may eventually contribute to the development of new treatments for human fungal diseases, the protection of important food crops, and a deeper understanding of the roles various fungi play in the broader ecosystem.
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Affiliation(s)
| | - Dominic Pinel
- Energy Biosciences Institute, Berkeley, United States
| | | | - Masakazu Ito
- Energy Biosciences Institute, Berkeley, United States
| | - Stephen J Mondo
- United States Department of Energy Joint Genome Institute, Walnut Creek, United States
| | - Morgann C Reilly
- Joint BioEnergy Institute, Emeryville, United States.,Chemical and Biological Processes Development Group, Pacific Northwest National Laboratory, Richland, United States
| | - Ya-Fang Cheng
- Energy Biosciences Institute, Berkeley, United States
| | - Stefan Bauer
- Energy Biosciences Institute, Berkeley, United States
| | - Igor V Grigoriev
- United States Department of Energy Joint Genome Institute, Walnut Creek, United States.,Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, United States.,Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, United States
| | | | - Blake A Simmons
- Joint BioEnergy Institute, Emeryville, United States.,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, United States
| | - Rachel B Brem
- The Buck Institute for Research on Aging, Novato, United States.,Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, United States
| | - Adam P Arkin
- Energy Biosciences Institute, Berkeley, United States.,Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, United States.,Department of Bioengineering, University of California, Berkeley, Berkeley, United States
| | - Jeffrey M Skerker
- Energy Biosciences Institute, Berkeley, United States.,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, United States.,Department of Bioengineering, University of California, Berkeley, Berkeley, United States
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26
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Choera T, Zelante T, Romani L, Keller NP. A Multifaceted Role of Tryptophan Metabolism and Indoleamine 2,3-Dioxygenase Activity in Aspergillus fumigatus-Host Interactions. Front Immunol 2018; 8:1996. [PMID: 29403477 PMCID: PMC5786828 DOI: 10.3389/fimmu.2017.01996] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 12/22/2017] [Indexed: 12/19/2022] Open
Abstract
Aspergillus fumigatus is the most prevalent filamentous fungal pathogen of humans, causing either severe allergic bronchopulmonary aspergillosis or often fatal invasive pulmonary aspergillosis (IPA) in individuals with hyper- or hypo-immune deficiencies, respectively. Disease is primarily initiated upon the inhalation of the ubiquitous airborne conidia—the initial inoculum produced by A. fumigatus—which are complete developmental units with an ability to exploit diverse environments, ranging from agricultural composts to animal lungs. Upon infection, conidia initially rely on their own metabolic processes for survival in the host’s lungs, a nutritionally limiting environment. One such nutritional limitation is the availability of aromatic amino acids (AAAs) as animals lack the enzymes to synthesize tryptophan (Trp) and phenylalanine and only produce tyrosine from dietary phenylalanine. However, A. fumigatus produces all three AAAs through the shikimate–chorismate pathway, where they play a critical role in fungal growth and development and in yielding many downstream metabolites. The downstream metabolites of Trp in A. fumigatus include the immunomodulatory kynurenine derived from indoleamine 2,3-dioxygenase (IDO) and toxins such as fumiquinazolines, gliotoxin, and fumitremorgins. Host IDO activity and/or host/microbe-derived kynurenines are increasingly correlated with many Aspergillus diseases including IPA and infections of chronic granulomatous disease patients. In this review, we will describe the potential metabolic cross talk between the host and the pathogen, specifically focusing on Trp metabolism, the implications for therapeutics, and the recent studies on the coevolution of host and microbe IDO activation in regulating inflammation, while controlling infection.
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Affiliation(s)
- Tsokyi Choera
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, United States
| | - Teresa Zelante
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Luigina Romani
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Nancy P Keller
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, United States.,Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, United States
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27
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Liu N, Tu J, Dong G, Wang Y, Sheng C. Emerging New Targets for the Treatment of Resistant Fungal Infections. J Med Chem 2018; 61:5484-5511. [DOI: 10.1021/acs.jmedchem.7b01413] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Na Liu
- School of Pharmacy, Second Military Medical University, 325 Guohe Road, Shanghai 200433, People’s Republic of China
| | - Jie Tu
- School of Pharmacy, Second Military Medical University, 325 Guohe Road, Shanghai 200433, People’s Republic of China
| | - Guoqiang Dong
- School of Pharmacy, Second Military Medical University, 325 Guohe Road, Shanghai 200433, People’s Republic of China
| | - Yan Wang
- School of Pharmacy, Second Military Medical University, 325 Guohe Road, Shanghai 200433, People’s Republic of China
| | - Chunquan Sheng
- School of Pharmacy, Second Military Medical University, 325 Guohe Road, Shanghai 200433, People’s Republic of China
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28
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Dietl AM, Meir Z, Shadkchan Y, Osherov N, Haas H. Riboflavin and pantothenic acid biosynthesis are crucial for iron homeostasis and virulence in the pathogenic mold Aspergillus fumigatus. Virulence 2018; 9:1036-1049. [PMID: 30052132 PMCID: PMC6068542 DOI: 10.1080/21505594.2018.1482181] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 05/22/2018] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Aspergillus fumigatus is the most prevalent airborne fungal pathogen, causing invasive fungal infections mainly in immunosuppressed individuals. Death rates from invasive aspergillosis remain high because of limited treatment options and increasing antifungal resistance. The aim of this study was to identify key fungal-specific genes participating in vitamin B biosynthesis in A. fumigatus. Because these genes are absent in humans they can serve as possible novel targets for antifungal drug development. METHODS By sequence homology we identified, deleted and analysed four key A. fumigatus genes (riboB, panA, pyroA, thiB) involved respectively in the biosynthesis of riboflavin (vitamin B2), pantothenic acid (vitamin B5), pyridoxine (vitamin B6) and thiamine (vitamin B1). RESULTS Deletion of riboB, panA, pyroA or thiB resulted in respective vitamin auxotrophy. Lack of riboflavin and pantothenic acid biosynthesis perturbed many cellular processes including iron homeostasis. Virulence in murine pulmonary and systemic models of infection was severely attenuated following deletion of riboB and panA, strongly reduced after pyroA deletion and weakly attenuated after thiB deletion. CONCLUSIONS This study reveals the biosynthetic pathways of the vitamins riboflavin and pantothenic acid as attractive targets for novel antifungal therapy. Moreover, the virulence studies with auxotrophic mutants serve to identify the availability of nutrients to pathogens in host niches. ABBREVIATIONS BPS: bathophenanthrolinedisulfonate; BSA: bovine serum albumin; CFU: colony forming unit; -Fe: iron starvation; +Fe: iron sufficiency; hFe: high iron; NRPSs: nonribosomal peptide synthetases; PKSs: polyketide synthaseses; wt: wild type.
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Affiliation(s)
- Anna-Maria Dietl
- Division of Molecular Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Zohar Meir
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine Ramat-Aviv, Tel-Aviv, Israel
| | - Yona Shadkchan
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine Ramat-Aviv, Tel-Aviv, Israel
| | - Nir Osherov
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine Ramat-Aviv, Tel-Aviv, Israel
| | - Hubertus Haas
- Division of Molecular Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
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29
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Verma S, Shakya VPS, Idnurm A. Exploring and exploiting the connection between mitochondria and the virulence of human pathogenic fungi. Virulence 2018; 9:426-446. [PMID: 29261004 PMCID: PMC5955198 DOI: 10.1080/21505594.2017.1414133] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 12/04/2017] [Accepted: 12/04/2017] [Indexed: 12/17/2022] Open
Abstract
Mitochondria are best known for their role in the production of ATP; however, recent research implicates other mitochondrial functions in the virulence of human pathogenic fungi. Inhibitors of mitochondrial succinate dehydrogenase or the electron transport chain are successfully used to combat plant pathogenic fungi, but similar inhibition of mitochondrial functions has not been pursued for applications in medical mycology. Advances in understanding mitochondrial function relevant to human pathogenic fungi are in four major directions: 1) the role of mitochondrial morphology in virulence, 2) mitochondrial genetics, with a focus on mitochondrial DNA recombination and mitochondrial inheritance 3) the role of mitochondria in drug resistance, and 4) the interaction of mitochondria with other organelles. Collectively, despite the similarities in mitochondrial functions between fungi and animals, this organelle is currently an under-explored potential target to treat medical mycoses. Future research could define and then exploit those mitochondrial components best suited as drug targets.
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Affiliation(s)
- Surbhi Verma
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Viplendra P. S. Shakya
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Alexander Idnurm
- School of BioSciences, University of Melbourne, Parkville, VIC, Australia
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30
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Yang CL, Wang J, Zou LL. Innate immune evasion strategies against Cryptococcal meningitis caused by Cryptococcus neoformans. Exp Ther Med 2017; 14:5243-5250. [PMID: 29285049 PMCID: PMC5740712 DOI: 10.3892/etm.2017.5220] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 05/31/2017] [Indexed: 12/14/2022] Open
Abstract
As an infectious fungus that affects the respiratory tract, Cryptococcus neoformans (C. neoformans) commonly causes asymptomatic pulmonary infection. C. neoformans may target the brain instead of the lungs and cross the blood-brain barrier (BBB) in the early phase of infection; however, this is dependent on successful evasion of the host innate immune system. During the initial stage of fungal infection, a complex network of innate immune factors are activated. C. neoformans utilizes a number of strategies to overcome the anti-fungal mechanisms of the host innate immune system and cross the BBB. In the present review, the defensive mechanisms of C. neoformans against the innate immune system and its ability to cross the BBB were discussed, with an emphasis on recent insights into the activities of anti-phagocytotic and anti-oxidative factors in C. neoformans.
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Affiliation(s)
- Cheng-Liang Yang
- Translational Neuroscience and Neural Regeneration and Repair Institute, The First Hospital of Yichang, China Three Gorges University, Yichang, Hubei 443002, P.R. China.,Institute of Cell Therapy, The First Hospital of Yichang, China Three Gorges University, Yichang, Hubei 443002, P.R. China
| | - Jun Wang
- Translational Neuroscience and Neural Regeneration and Repair Institute, The First Hospital of Yichang, China Three Gorges University, Yichang, Hubei 443002, P.R. China.,Institute of Cell Therapy, The First Hospital of Yichang, China Three Gorges University, Yichang, Hubei 443002, P.R. China
| | - Li-Li Zou
- Translational Neuroscience and Neural Regeneration and Repair Institute, The First Hospital of Yichang, China Three Gorges University, Yichang, Hubei 443002, P.R. China.,Institute of Cell Therapy, The First Hospital of Yichang, China Three Gorges University, Yichang, Hubei 443002, P.R. China.,Department of Microbiology and Immunology, Medical College, China Three Gorges University, Yichang, Hubei 443002, P.R. China
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31
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Idnurm A, Bailey AM, Cairns TC, Elliott CE, Foster GD, Ianiri G, Jeon J. A silver bullet in a golden age of functional genomics: the impact of Agrobacterium-mediated transformation of fungi. Fungal Biol Biotechnol 2017; 4:6. [PMID: 28955474 PMCID: PMC5615635 DOI: 10.1186/s40694-017-0035-0] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 09/18/2017] [Indexed: 11/10/2022] Open
Abstract
The implementation of Agrobacterium tumefaciens as a transformation tool revolutionized approaches to discover and understand gene functions in a large number of fungal species. A. tumefaciens mediated transformation (AtMT) is one of the most transformative technologies for research on fungi developed in the last 20 years, a development arguably only surpassed by the impact of genomics. AtMT has been widely applied in forward genetics, whereby generation of strain libraries using random T-DNA insertional mutagenesis, combined with phenotypic screening, has enabled the genetic basis of many processes to be elucidated. Alternatively, AtMT has been fundamental for reverse genetics, where mutant isolates are generated with targeted gene deletions or disruptions, enabling gene functional roles to be determined. When combined with concomitant advances in genomics, both forward and reverse approaches using AtMT have enabled complex fungal phenotypes to be dissected at the molecular and genetic level. Additionally, in several cases AtMT has paved the way for the development of new species to act as models for specific areas of fungal biology, particularly in plant pathogenic ascomycetes and in a number of basidiomycete species. Despite its impact, the implementation of AtMT has been uneven in the fungi. This review provides insight into the dynamics of expansion of new research tools into a large research community and across multiple organisms. As such, AtMT in the fungi, beyond the demonstrated and continuing power for gene discovery and as a facile transformation tool, provides a model to understand how other technologies that are just being pioneered, e.g. CRISPR/Cas, may play roles in fungi and other eukaryotic species.
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Affiliation(s)
- Alexander Idnurm
- School of BioSciences, University of Melbourne, Melbourne, VIC 3010 Australia
| | - Andy M. Bailey
- School of Biological Sciences, University of Bristol, Bristol, UK
| | - Timothy C. Cairns
- Department of Applied and Molecular Microbiology, Technische Universität Berlin, Berlin, Germany
| | - Candace E. Elliott
- School of BioSciences, University of Melbourne, Melbourne, VIC 3010 Australia
| | - Gary D. Foster
- School of Biological Sciences, University of Bristol, Bristol, UK
| | - Giuseppe Ianiri
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, USA
| | - Junhyun Jeon
- College of Life and Applied Sciences, Yeungnam University, Gyeongsan, South Korea
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32
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Staerck C, Gastebois A, Vandeputte P, Calenda A, Larcher G, Gillmann L, Papon N, Bouchara JP, Fleury MJ. Microbial antioxidant defense enzymes. Microb Pathog 2017. [DOI: 10.1016/j.micpath.2017.06.015] [Citation(s) in RCA: 111] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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33
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Santos JRA, Ribeiro NQ, Bastos RW, Holanda RA, Silva LC, Queiroz ER, Santos DA. High-dose fluconazole in combination with amphotericin B is more efficient than monotherapy in murine model of cryptococcosis. Sci Rep 2017; 7:4661. [PMID: 28680034 PMCID: PMC5498649 DOI: 10.1038/s41598-017-04588-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 05/17/2017] [Indexed: 12/26/2022] Open
Abstract
Cryptococcus spp., the causative agents of cryptococcosis, are responsible for deaths of hundreds of thousands of people every year worldwide. The drawbacks of available therapeutic options are aggravated by the increased resistance of yeast to the drugs, resulting in inefficient therapy. Also, the antifungal 5FC is not available in many countries. Therefore, a combination of antifungal drugs may be an interesting option, but in vitro and theoretical data point to the possible antagonism between the main antifungals used to treat cryptococcosis, i.e., fluconazole (FLC), and amphotericin B (AMB). Therefore, in vivo studies are necessary to test the above hypothesis. In this study, the efficacy of FLC and AMB at controlling C. gattii infection was evaluated in a murine model of cryptococcosis caused by C. gattii. The infected mice were treated with FLC + AMB combinations and showed a significant improvement in survival as well as reduced morbidity, reduced lung fungal burden, and the absence of yeast in the brain when FLC was used at higher doses, according to the Tukey test and principal component analysis. Altogether, these results indicate that combinatorial optimization of antifungal therapy can be an option for effective control of cryptococcosis.
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Affiliation(s)
- Julliana Ribeiro Alves Santos
- Mestrado em Biologia Parasitária - Universidade CEUMA (UNICEUMA), São Luís, Maranhão, Brazil. .,Mestrado em Meio Ambiente - Universidade CEUMA (UNICEUMA), São Luís, Maranhão, Brazil.
| | - Noelly Queiroz Ribeiro
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Rafael Wesley Bastos
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | | | - Letícia Chagas Silva
- Mestrado em Meio Ambiente - Universidade CEUMA (UNICEUMA), São Luís, Maranhão, Brazil
| | - Estela Rezende Queiroz
- Departamento de Química, Universidade Federal de Lavras (UFLA), Campus 17 Universitário, Lavras- MG, Brazil
| | - Daniel Assis Santos
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
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34
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Microevolution of Serial Clinical Isolates of Cryptococcus neoformans var. grubii and C. gattii. mBio 2017; 8:mBio.00166-17. [PMID: 28270580 PMCID: PMC5340869 DOI: 10.1128/mbio.00166-17] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The pathogenic species of Cryptococcus are a major cause of mortality owing to severe infections in immunocompromised as well as immunocompetent individuals. Although antifungal treatment is usually effective, many patients relapse after treatment, and in such cases, comparative analyses of the genomes of incident and relapse isolates may reveal evidence of determinative, microevolutionary changes within the host. Here, we analyzed serial isolates cultured from cerebrospinal fluid specimens of 18 South African patients with recurrent cryptococcal meningitis. The time between collection of the incident isolates and collection of the relapse isolates ranged from 124 days to 290 days, and the analyses revealed that, during this period within the patients, the isolates underwent several genetic and phenotypic changes. Considering the vast genetic diversity of cryptococcal isolates in sub-Saharan Africa, it was not surprising to find that the relapse isolates had acquired different genetic and correlative phenotypic changes. They exhibited various mechanisms for enhancing virulence, such as growth at 39°C, adaptation to stress, and capsule production; a remarkable amplification of ERG11 at the native and unlinked locus may provide stable resistance to fluconazole. Our data provide a deeper understanding of the microevolution of Cryptococcus species under pressure from antifungal chemotherapy and host immune responses. This investigation clearly suggests a promising strategy to identify novel targets for improved diagnosis, therapy, and prognosis. Opportunistic infections caused by species of the pathogenic yeast Cryptococcus lead to chronic meningoencephalitis and continue to ravage thousands of patients with HIV/AIDS. Despite receiving antifungal treatment, over 10% of patients develop recurrent disease. In this study, we collected isolates of Cryptococcus from cerebrospinal fluid specimens of 18 patients at the time of their diagnosis and when they relapsed several months later. We then sequenced and compared the genomic DNAs of each pair of initial and relapse isolates. We also tested the isolates for several key properties related to cryptococcal virulence as well as for their susceptibility to the antifungal drug fluconazole. These analyses revealed that the relapsing isolates manifested multiple genetic and chromosomal changes that affected a variety of genes implicated in the pathogenicity of Cryptococcus or resistance to fluconazole. This application of comparative genomics to serial clinical isolates provides a blueprint for identifying the mechanisms whereby pathogenic microbes adapt within patients to prolong disease.
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35
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Yang DH, Jung KW, Bang S, Lee JW, Song MH, Floyd-Averette A, Festa RA, Ianiri G, Idnurm A, Thiele DJ, Heitman J, Bahn YS. Rewiring of Signaling Networks Modulating Thermotolerance in the Human Pathogen Cryptococcus neoformans. Genetics 2017; 205:201-219. [PMID: 27866167 PMCID: PMC5223503 DOI: 10.1534/genetics.116.190595] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 11/08/2016] [Indexed: 01/17/2023] Open
Abstract
Thermotolerance is a crucial virulence attribute for human pathogens, including the fungus Cryptococcus neoformans that causes fatal meningitis in humans. Loss of the protein kinase Sch9 increases C. neoformans thermotolerance, but its regulatory mechanism has remained unknown. Here, we studied the Sch9-dependent and Sch9-independent signaling networks modulating C. neoformans thermotolerance by using genome-wide transcriptome analysis and reverse genetic approaches. During temperature upshift, genes encoding for molecular chaperones and heat shock proteins were upregulated, whereas those for translation, transcription, and sterol biosynthesis were highly suppressed. In this process, Sch9 regulated basal expression levels or induced/repressed expression levels of some temperature-responsive genes, including heat shock transcription factor (HSF1) and heat shock proteins (HSP104 and SSA1). Notably, we found that the HSF1 transcript abundance decreased but the Hsf1 protein became transiently phosphorylated during temperature upshift. Nevertheless, Hsf1 is essential for growth and its overexpression promoted C. neoformans thermotolerance. Transcriptome analysis using an HSF1 overexpressing strain revealed a dual role of Hsf1 in the oxidative stress response and thermotolerance. Chromatin immunoprecipitation demonstrated that Hsf1 binds to the step-type like heat shock element (HSE) of its target genes more efficiently than to the perfect- or gap-type HSE. This study provides insight into the thermotolerance of C. neoformans by elucidating the regulatory mechanisms of Sch9 and Hsf1 through the genome-scale identification of temperature-dependent genes.
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Affiliation(s)
- Dong-Hoon Yang
- Department of Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
| | - Kwang-Woo Jung
- Department of Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
| | - Soohyun Bang
- Department of Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
| | - Jang-Won Lee
- Department of Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
| | - Min-Hee Song
- Department of Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
| | - Anna Floyd-Averette
- Departments of Molecular Genetics and Microbiology, Medicine, and Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710
| | - Richard A Festa
- Departments of Pharmacology and Cancer Biology and Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina 27710
| | - Giuseppe Ianiri
- Departments of Molecular Genetics and Microbiology, Medicine, and Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710
| | - Alexander Idnurm
- School of BioSciences, University of Melbourne, Victoria 3010, Australia
| | - Dennis J Thiele
- Departments of Pharmacology and Cancer Biology and Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina 27710
| | - Joseph Heitman
- Departments of Molecular Genetics and Microbiology, Medicine, and Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710
| | - Yong-Sun Bahn
- Department of Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
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Woolford CA, Lagree K, Xu W, Aleynikov T, Adhikari H, Sanchez H, Cullen PJ, Lanni F, Andes DR, Mitchell AP. Bypass of Candida albicans Filamentation/Biofilm Regulators through Diminished Expression of Protein Kinase Cak1. PLoS Genet 2016; 12:e1006487. [PMID: 27935965 PMCID: PMC5147786 DOI: 10.1371/journal.pgen.1006487] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 11/15/2016] [Indexed: 12/17/2022] Open
Abstract
Biofilm formation on implanted medical devices is a major source of lethal invasive infection by Candida albicans. Filamentous growth of this fungus is tied to biofilm formation because many filamentation-associated genes are required for surface adherence. Cell cycle or cell growth defects can induce filamentation, but we have limited information about the coupling between filamentation and filamentation-associated gene expression after cell cycle/cell growth inhibition. Here we identified the CDK activating protein kinase Cak1 as a determinant of filamentation and filamentation-associated gene expression through a screen of mutations that diminish expression of protein kinase-related genes implicated in cell cycle/cell growth control. A cak1diminished expression (DX) strain displays filamentous growth and expresses filamentation-associated genes in the absence of typical inducing signals. In a wild-type background, expression of filamentation-associated genes depends upon the transcription factors Bcr1, Brg1, Efg1, Tec1, and Ume6. In the cak1 DX background, the dependence of filamentation-associated gene expression on each transcription factor is substantially relieved. The unexpected bypass of filamentation-associated gene expression activators has the functional consequence of enabling biofilm formation in the absence of Bcr1, Brg1, Tec1, Ume6, or in the absence of both Brg1 and Ume6. It also enables filamentous cell morphogenesis, though not biofilm formation, in the absence of Efg1. Because these transcription factors are known to have shared target genes, we suggest that cell cycle/cell growth limitation leads to activation of several transcription factors, thus relieving dependence on any one. The ability of the pathogen Candida albicans to grow on surfaces as biofilms is a determinant of infection ability, because biofilms on implanted medical devices seed infections. Biofilm formation by this organism requires growth in the form of filamentous cells and the expression of filamentation-associated genes. Inhibition of cell proliferation can induce filamentous cell formation, as we find here for strains that express greatly reduced levels of the cell cycle regulator Cak1. Surprisingly, biofilm formation occurs independently of many central biofilm regulatory genes when Cak1 levels are reduced. This response to proliferation inhibition may reflect the activation of numerous biofilm regulators, thus relieving the dependence on any one regulator. The stimulation of biofilm formation by proliferation inhibition, a property of many bacterial pathogens as well, may contribute to the limited effectiveness of antimicrobials against biofilms.
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Affiliation(s)
- Carol A. Woolford
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Katherine Lagree
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Wenjie Xu
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Tatyana Aleynikov
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Hema Adhikari
- Department of Biological Sciences at the University at Buffalo, Buffalo, New York, United States of America
| | - Hiram Sanchez
- Departments of Medicine and Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Paul J. Cullen
- Department of Biological Sciences at the University at Buffalo, Buffalo, New York, United States of America
| | - Frederick Lanni
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - David R. Andes
- Departments of Medicine and Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Aaron P. Mitchell
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
- * E-mail:
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38
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Ianiri G, Boyce KJ, Idnurm A. Isolation of conditional mutations in genes essential for viability of Cryptococcus neoformans. Curr Genet 2016; 63:519-530. [PMID: 27783209 DOI: 10.1007/s00294-016-0659-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Revised: 10/02/2016] [Accepted: 10/18/2016] [Indexed: 10/20/2022]
Abstract
Discovering the genes underlying fundamental processes that enable cells to live and reproduce is a technical challenge, because loss of gene function in mutants results in organisms that cannot survive. This study describes a forward genetics method to identify essential genes in fungi, based on the propensity for Agrobacterium tumefaciens to insert T-DNA molecules into the promoters or 5' untranslated regions of genes and by placing a conditional promoter within the T-DNA. Insertions of the promoter of the GAL7 gene were made in the human pathogen Cryptococcus neoformans. Nine strains of 960 T-DNA insertional mutants screened grew on media containing galactose, but had impaired growth on media containing glucose, which suppresses expression from GAL7. T-DNA insertions were found in the homologs of IDI1, MRPL37, NOC3, NOP56, PRE3 and RPL17, all of which are essential in ascomycete yeasts Saccharomyces cerevisiae or Schizosaccharomyces pombe. Altering the carbon source in the medium provided a system to identify phenotypes in response to stress agents. The pre3 proteasome subunit mutant was further characterized. The T-DNA insertion and phenotype co-segregate in progeny from a cross, and the growth defect is complemented by the reintroduction of the wild type gene into the insertional mutant. A deletion allele was generated in a diploid strain, this heterozygous strain was sporulated, and analysis of the progeny provided additional genetic evidence that PRE3 is essential. The experimental design is applicable to other fungi and has other forward genetic applications such as to isolate over-expression suppressors or enhance the production of traits of interest.
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Affiliation(s)
- Giuseppe Ianiri
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, 27710, USA.,Dipartimento di Agricoltura, Ambiente e Alimenti, Università degli Studi del Molise, Via F. De Sanctis Snc, 86100, Campobasso, Italy
| | - Kylie J Boyce
- School of BioSciences, BioSciences 2, University of Melbourne, Building 122, Melbourne, VIC, 3010, Australia
| | - Alexander Idnurm
- School of BioSciences, BioSciences 2, University of Melbourne, Building 122, Melbourne, VIC, 3010, Australia.
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Forsythe A, Vogan A, Xu J. Genetic and environmental influences on the germination of basidiospores in the Cryptococcus neoformans species complex. Sci Rep 2016; 6:33828. [PMID: 27644692 PMCID: PMC5028750 DOI: 10.1038/srep33828] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 08/30/2016] [Indexed: 12/12/2022] Open
Abstract
In basidiomycetous fungi, the viability of basidiospores is an important component of sexual fitness. However, relatively little is known about the genetic and environmental factors influencing basidiospore germination. In this study, we used human opportunistic yeast pathogens, Cryptococcus neoformans and Cryptococcus deneoformans, as models to investigate the potential effects of selected genetic and environmental factors on basidiospore germination. A total of five strains with known genome structure were used to construct six crosses, three of which were between strains within the same species, while the remaining three were hybrid crosses between C. neoformans and C. deneoformans. Offspring from these crosses were incubated on two media (a nutrient-limiting and a nutrient-rich) and three temperatures (23 °C, 30 °C, and 37 °C). In general, spores from intra-specific crosses had greater germination rates than those from inter-specific crosses. Of the two environmental factors, temperature showed a greater influence than nutrient medium, with the 37 °C environment yielding lower germination rates than at 23 °C and 30 °C environments in most crosses. Furthermore, there were notable interaction effects between environmental factors and parental strains or strain pairs on basidiospore germination. We discuss the implications of these results on pathogenesis and speciation in this human fungal pathogen.
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Affiliation(s)
- Adrian Forsythe
- Department of Biology, McMaster University, 1280 Main St West, Hamilton, Ontario, L8S 4K1, Canada
| | - Aaron Vogan
- Department of Biology, McMaster University, 1280 Main St West, Hamilton, Ontario, L8S 4K1, Canada
| | - Jianping Xu
- Department of Biology, McMaster University, 1280 Main St West, Hamilton, Ontario, L8S 4K1, Canada
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Ding H, Mayer FL, Sánchez-León E, de S Araújo GR, Frases S, Kronstad JW. Networks of fibers and factors: regulation of capsule formation in Cryptococcus neoformans. F1000Res 2016; 5. [PMID: 27516877 PMCID: PMC4979528 DOI: 10.12688/f1000research.8854.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/12/2016] [Indexed: 12/15/2022] Open
Abstract
The ability of the pathogenic fungus
Cryptococcus neoformans to cause life-threatening meningoencephalitis in immunocompromised individuals is due in large part to elaboration of a capsule consisting of polysaccharide fibers. The size of the cell-associated capsule is remarkably responsive to a variety of environmental and host conditions, but the mechanistic details of the regulation, synthesis, trafficking, and attachment of the polysaccharides are poorly understood. Recent studies reveal a complex network of transcription factors that influence capsule elaboration in response to several different signals of relevance to disease (e.g., iron deprivation). The emerging complexity of the network is consistent with the diversity of conditions that influence the capsule and illustrates the responsiveness of the fungus to both the environment and mammalian hosts.
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Affiliation(s)
- Hao Ding
- Michael Smith Laboratories, University of British Columbia, Vancouver, Canada
| | - François L Mayer
- Michael Smith Laboratories, University of British Columbia, Vancouver, Canada
| | - Eddy Sánchez-León
- Michael Smith Laboratories, University of British Columbia, Vancouver, Canada
| | - Glauber R de S Araújo
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Susana Frases
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - James W Kronstad
- Michael Smith Laboratories, University of British Columbia, Vancouver, Canada.,Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
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Coelho C, Casadevall A. Cryptococcal therapies and drug targets: the old, the new and the promising. Cell Microbiol 2016; 18:792-9. [PMID: 26990050 DOI: 10.1111/cmi.12590] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 02/28/2016] [Accepted: 03/08/2016] [Indexed: 01/09/2023]
Abstract
Half a century after the introduction of Amphotericin B the management of cryptococcosis remains unsatisfactory. The disease, caused primarily by the two fungal species Cryptococcus neoformans and Cryptococcus gattii, remains responsible for considerable morbidity and mortality despite standard medical care. Current therapeutic options are limited to Amphotericin B, azoles and 5-flucytosine. However, this organism has numerous well-characterized virulence mechanisms that are amenable to pharmacological interference and are thus potential therapeutic targets. Here, we discuss existing approved antifungal drugs, resistance mechanisms to these drugs and non-standard antifungal drugs that have potential in treatment of cryptococcosis, including immunomodulatory strategies that synergize with antifungal drugs, such as cytokine administration or monoclonal antibodies. Finally, we summarize attempts to target well-described virulence factors of Cryptococcus, the capsule or fungal melanin. This review emphasizes the pressing need for new therapeutic alternatives for cryptococcosis.
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Affiliation(s)
- Carolina Coelho
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Arturo Casadevall
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
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Abstract
New state-of-the-art techniques in sequencing offer valuable tools in both detection of mycobiota and in understanding of the molecular mechanisms of resistance against antifungal compounds and virulence. Introduction of new sequencing platform with enhanced capacity and a reduction in costs for sequence analysis provides a potential powerful tool in mycological diagnosis and research. In this review, we summarize the applications of next-generation sequencing techniques in mycology.
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Abstract
BACKGROUND We identified auranofin as an antimicrobial compound utilizing a high-throughput screen using a Caenorhabditis elegans-Staphylococcus aureus infection model. Results/methodology: Treatment of infected nematodes with auranofin resulted in a prolonged survival rate of 95%, reached with 0.78 μg/ml. Further investigation of the antimicrobial activity of auranofin found inhibition against S. aureus, Enterococcus faecium and Enterococcus faecalis. Importantly, the fungal pathogens Cryptococcus neoformans was also effectively inhibited with an MIC at 0.5 μg/ml. Auranofin appears to target the thioredoxin system. CONCLUSION This work provides extensive additional data on the antibacterial effects of auranofin that includes both reference and clinical isolates and reports a novel inhibition of fungal pathogens by this compound.
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Abadio AKR, Kioshima ES, Leroux V, Martins NF, Maigret B, Felipe MSS. Identification of New Antifungal Compounds Targeting Thioredoxin Reductase of Paracoccidioides Genus. PLoS One 2015; 10:e0142926. [PMID: 26569405 PMCID: PMC4646694 DOI: 10.1371/journal.pone.0142926] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2015] [Accepted: 10/28/2015] [Indexed: 11/27/2022] Open
Abstract
The prevalence of invasive fungal infections worldwide has increased in the last decades. The development of specific drugs targeting pathogenic fungi without producing collateral damage to mammalian cells is a daunting pharmacological challenge. Indeed, many of the toxicities and drug interactions observed with contemporary antifungal therapies can be attributed to “nonselective” interactions with enzymes or cell membrane systems found in mammalian host cells. A computer-aided screening strategy against the TRR1 protein of Paracoccidioides lutzii is presented here. Initially, a bank of commercially available compounds from Life Chemicals provider was docked to model by virtual screening simulations. The small molecules that interact with the model were ranked and, among the best hits, twelve compounds out of 3,000 commercially-available candidates were selected. These molecules were synthesized for validation and in vitro antifungal activity assays for Paracoccidioides lutzii and P. brasiliensis were performed. From 12 molecules tested, 3 harbor inhibitory activity in antifungal assays against the two pathogenic fungi. Corroborating these findings, the molecules have inhibitory activity against the purified recombinant enzyme TRR1 in biochemical assays. Therefore, a rational combination of molecular modeling simulations and virtual screening of new drugs has provided a cost-effective solution to an early-stage medicinal challenge. These results provide a promising technique to the development of new and innovative drugs.
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Affiliation(s)
| | - Erika Seki Kioshima
- Department of Clinical Analysis and Biomedicine, State University of Maringá, Maringá, Paraná, Brazil
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Cairns TC, Studholme DJ, Talbot NJ, Haynes K. New and Improved Techniques for the Study of Pathogenic Fungi. Trends Microbiol 2015; 24:35-50. [PMID: 26549580 DOI: 10.1016/j.tim.2015.09.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2015] [Revised: 09/29/2015] [Accepted: 09/30/2015] [Indexed: 02/05/2023]
Abstract
Fungal pathogens pose serious threats to human, plant, and ecosystem health. Improved diagnostics and antifungal strategies are therefore urgently required. Here, we review recent developments in online bioinformatic tools and associated interactive data archives, which enable sophisticated comparative genomics and functional analysis of fungal pathogens in silico. Additionally, we highlight cutting-edge experimental techniques, including conditional expression systems, recyclable markers, RNA interference, genome editing, compound screens, infection models, and robotic automation, which are promising to revolutionize the study of both human and plant pathogenic fungi. These novel techniques will allow vital knowledge gaps to be addressed with regard to the evolution of virulence, host-pathogen interactions and antifungal drug therapies in both the clinic and agriculture. This, in turn, will enable delivery of improved diagnosis and durable disease-control strategies.
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Affiliation(s)
- Timothy C Cairns
- Institut für Biotechnologie, Technische Universität Berlin, Gustav-Meyer Allee 22, Berlin, Germany.
| | | | | | - Ken Haynes
- Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
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Protein Composition of Infectious Spores Reveals Novel Sexual Development and Germination Factors in Cryptococcus. PLoS Genet 2015; 11:e1005490. [PMID: 26313153 PMCID: PMC4551743 DOI: 10.1371/journal.pgen.1005490] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 08/07/2015] [Indexed: 11/19/2022] Open
Abstract
Spores are an essential cell type required for long-term survival across diverse organisms in the tree of life and are a hallmark of fungal reproduction, persistence, and dispersal. Among human fungal pathogens, spores are presumed infectious particles, but relatively little is known about this robust cell type. Here we used the meningitis-causing fungus Cryptococcus neoformans to determine the roles of spore-resident proteins in spore biology. Using highly sensitive nanoscale liquid chromatography/mass spectrometry, we compared the proteomes of spores and vegetative cells (yeast) and identified eighteen proteins specifically enriched in spores. The genes encoding these proteins were deleted, and the resulting strains were evaluated for discernable phenotypes. We hypothesized that spore-enriched proteins would be preferentially involved in spore-specific processes such as dormancy, stress resistance, and germination. Surprisingly, however, the majority of the mutants harbored defects in sexual development, the process by which spores are formed. One mutant in the cohort was defective in the spore-specific process of germination, showing a delay specifically in the initiation of vegetative growth. Thus, by using this in-depth proteomics approach as a screening tool for cell type-specific proteins and combining it with molecular genetics, we successfully identified the first germination factor in C. neoformans. We also identified numerous proteins with previously unknown functions in both sexual development and spore composition. Our findings provide the first insights into the basic protein components of infectious spores and reveal unexpected molecular connections between infectious particle production and spore composition in a pathogenic eukaryote.
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