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Zhou X, Hilk A, Solis NV, Scott N, Beach A, Soisangwan N, Billings CL, Burrack LS, Filler SG, Selmecki A. Single-cell detection of copy number changes reveals dynamic mechanisms of adaptation to antifungals in Candida albicans. Nat Microbiol 2024:10.1038/s41564-024-01795-7. [PMID: 39227665 DOI: 10.1038/s41564-024-01795-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Accepted: 07/24/2024] [Indexed: 09/05/2024]
Abstract
Genomic copy number changes are associated with antifungal drug resistance and virulence across diverse fungal pathogens, but the rate and dynamics of these genomic changes in the presence of antifungal drugs are unknown. Here we optimized a dual-fluorescent reporter system in the diploid pathogen Candida albicans to quantify haplotype-specific copy number variation (CNV) and loss of heterozygosity (LOH) at the single-cell level with flow cytometry. We followed the frequency and dynamics of CNV and LOH at two distinct genomic locations in the presence and absence of antifungal drugs in vitro and in a murine model of candidiasis. Copy number changes were rapid and dynamic during adaptation to fluconazole and frequently involved competing subpopulations with distinct genotypes. This study provides quantitative evidence for the rapid speed at which diverse genotypes arise and undergo dynamic population-level fluctuations during adaptation to antifungal drugs in vitro and in vivo.
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Affiliation(s)
- Xin Zhou
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, USA
| | - Audrey Hilk
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, USA
| | - Norma V Solis
- Division of Infectious Diseases, Lundquist Institute for Biomedical Innovation at Harbor UCLA Medical Center, Torrance, CA, USA
| | - Nancy Scott
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, USA
| | - Annette Beach
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, USA
| | - Natthapon Soisangwan
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, USA
| | - Clara L Billings
- Gustavus Adolphus College, Department of Biology, Saint Peter, MN, USA
| | - Laura S Burrack
- Gustavus Adolphus College, Department of Biology, Saint Peter, MN, USA
| | - Scott G Filler
- Division of Infectious Diseases, Lundquist Institute for Biomedical Innovation at Harbor UCLA Medical Center, Torrance, CA, USA
- David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Anna Selmecki
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, USA.
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2
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Schaefer S, Vij R, Sprague JL, Austermeier S, Dinh H, Judzewitsch PR, Müller-Loennies S, Lopes Silva T, Seemann E, Qualmann B, Hertweck C, Scherlach K, Gutsmann T, Cain AK, Corrigan N, Gresnigt MS, Boyer C, Lenardon MD, Brunke S. A synthetic peptide mimic kills Candida albicans and synergistically prevents infection. Nat Commun 2024; 15:6818. [PMID: 39122699 PMCID: PMC11315985 DOI: 10.1038/s41467-024-50491-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 07/11/2024] [Indexed: 08/12/2024] Open
Abstract
More than two million people worldwide are affected by life-threatening, invasive fungal infections annually. Candida species are the most common cause of nosocomial, invasive fungal infections and are associated with mortality rates above 40%. Despite the increasing incidence of drug-resistance, the development of novel antifungal formulations has been limited. Here we investigate the antifungal mode of action and therapeutic potential of positively charged, synthetic peptide mimics to combat Candida albicans infections. Our data indicates that these synthetic polymers cause endoplasmic reticulum stress and affect protein glycosylation, a mode of action distinct from currently approved antifungal drugs. The most promising polymer composition damaged the mannan layer of the cell wall, with additional membrane-disrupting activity. The synergistic combination of the polymer with caspofungin prevented infection of human epithelial cells in vitro, improved fungal clearance by human macrophages, and significantly increased host survival in a Galleria mellonella model of systemic candidiasis. Additionally, prolonged exposure of C. albicans to the synergistic combination of polymer and caspofungin did not lead to the evolution of tolerant strains in vitro. Together, this work highlights the enormous potential of these synthetic peptide mimics to be used as novel antifungal formulations as well as adjunctive antifungal therapy.
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Affiliation(s)
- Sebastian Schaefer
- School of Chemical Engineering, University of New South Wales (UNSW), Sydney, NSW, Australia
- Australian Centre for NanoMedicine, UNSW, Sydney, NSW, Australia
- School of Biotechnology and Biomolecular Sciences, UNSW, Sydney, NSW, Australia
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany
| | - Raghav Vij
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany
| | - Jakob L Sprague
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany
| | - Sophie Austermeier
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany
| | - Hue Dinh
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, North Ryde, NSW, Australia
| | - Peter R Judzewitsch
- School of Chemical Engineering, University of New South Wales (UNSW), Sydney, NSW, Australia
- Australian Centre for NanoMedicine, UNSW, Sydney, NSW, Australia
| | - Sven Müller-Loennies
- Division of Biophysics, Research Center Borstel, Leibniz Lung Center, Borstel, Germany
| | - Taynara Lopes Silva
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany
| | - Eric Seemann
- Institute of Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
| | - Britta Qualmann
- Institute of Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
| | - Christian Hertweck
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany
- Faculty of Biological Sciences, Friedrich Schiller University Jena, Jena, Germany
- Cluster of Excellence Balance of the Microverse, Friedrich Schiller University Jena, Jena, Germany
| | - Kirstin Scherlach
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany
| | - Thomas Gutsmann
- Division of Biophysics, Research Center Borstel, Leibniz Lung Center, Borstel, Germany
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
| | - Amy K Cain
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, North Ryde, NSW, Australia
| | - Nathaniel Corrigan
- School of Chemical Engineering, University of New South Wales (UNSW), Sydney, NSW, Australia
- Australian Centre for NanoMedicine, UNSW, Sydney, NSW, Australia
| | - Mark S Gresnigt
- Cluster of Excellence Balance of the Microverse, Friedrich Schiller University Jena, Jena, Germany
- Junior Research Group Adaptive Pathogenicity Strategies, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany
| | - Cyrille Boyer
- School of Chemical Engineering, University of New South Wales (UNSW), Sydney, NSW, Australia.
- Australian Centre for NanoMedicine, UNSW, Sydney, NSW, Australia.
| | - Megan D Lenardon
- School of Biotechnology and Biomolecular Sciences, UNSW, Sydney, NSW, Australia.
| | - Sascha Brunke
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany.
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3
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Zheng L, Xu Y, Wang C, Guo L. Ketoconazole induces reversible antifungal drug tolerance mediated by trisomy of chromosome R in Candida albicans. Front Microbiol 2024; 15:1450557. [PMID: 39139375 PMCID: PMC11319258 DOI: 10.3389/fmicb.2024.1450557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2024] [Accepted: 07/18/2024] [Indexed: 08/15/2024] Open
Abstract
Background The emergence of tolerance to antifungal agents in Candida albicans complicates the treatment of fungal infections. Understanding the mechanisms underlying this tolerance is crucial for developing effective therapeutic strategies. Objective This study aims to elucidate the genetic and molecular basis of ketoconazole tolerance in C. albicans, focusing on the roles of chromosomal aneuploidy, Hsp90, and calcineurin. Methods The wild-type C. albicans strain SC5314 was exposed to increasing concentrations of ketoconazole (0.015-32 μg/mL) to select for tolerant adaptors. Disk diffusion and spot assays were used to assess tolerance. Whole-genome sequencing identified chromosomal changes in the adaptors. The roles of Hsp90 and calcineurin in maintaining and developing ketoconazole tolerance were investigated using specific inhibitors and knockout strains. Results Adaptors exhibited tolerance to ketoconazole concentrations up to 16 μg/mL, a significant increase from the parent strain's inhibition at 0.015 μg/mL. All tolerant adaptors showed amplification of chromosome R, with 29 adaptors having trisomy and one having tetrasomy. This aneuploidy was unstable, reverting to euploidy and losing tolerance in drug-free conditions. Both Hsp90 and calcineurin were essential for maintaining and developing ketoconazole tolerance. Inhibition of these proteins resulted in loss of tolerance. The efflux gene CDR1 was not required for the development of tolerance. Chromosome R trisomy and tetrasomy induce cross-tolerance to other azole antifungal agents, including clotrimazole and miconazole, but not to other antifungal classes, such as echinocandins and pyrimidines, exemplified by caspofungin and 5-flucytosine. Conclusion Ketoconazole tolerance in C. albicans is mediated by chromosomal aneuploidy, specifically chromosome R amplification, and requires Hsp90 and calcineurin. These findings highlight potential targets for therapeutic intervention to combat antifungal tolerance and improve treatment outcomes.
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Affiliation(s)
- Lijun Zheng
- Department of Ultrasound Medicine, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Yi Xu
- Department of Pharmacy, The 960th Hospital of PLA, Jinan, China
| | - Chen Wang
- Department of Pharmacy, The 960th Hospital of PLA, Jinan, China
| | - Liangsheng Guo
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Soochow University, Suzhou, China
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4
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Guo L, Zheng L, Dong Y, Wang C, Deng H, Wang Z, Xu Y. Miconazole induces aneuploidy-mediated tolerance in Candida albicans that is dependent on Hsp90 and calcineurin. Front Cell Infect Microbiol 2024; 14:1392564. [PMID: 38983116 PMCID: PMC11231705 DOI: 10.3389/fcimb.2024.1392564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 06/12/2024] [Indexed: 07/11/2024] Open
Abstract
Antifungal resistance and antifungal tolerance are two distinct terms that describe different cellular responses to drugs. Antifungal resistance describes the ability of a fungus to grow above the minimal inhibitory concentration (MIC) of a drug. Antifungal tolerance describes the ability of drug susceptible strains to grow slowly at inhibitory drug concentrations. Recent studies indicate antifungal resistance and tolerance have distinct evolutionary trajectories. Superficial candidiasis bothers millions of people yearly. Miconazole has been used for topical treatment of yeast infections for over 40 years. Yet, fungal resistance to miconazole remains relatively low. Here we found different clinical isolates of Candida albicans had different profile of tolerance to miconazole, and the tolerance was modulated by physiological factors including temperature and medium composition. Exposure of non-tolerant strains with different genetic backgrounds to miconazole mainly induced development of tolerance, not resistance, and the tolerance was mainly due to whole chromosomal or segmental amplification of chromosome R. The efflux gene CDR1 was required for maintenance of tolerance in wild type strains but not required for gain of aneuploidy-mediated tolerance. Heat shock protein Hsp90 and calcineurin were essential for maintenance as well as gain of tolerance. Our study indicates development of aneuploidy-mediated tolerance, not resistance, is the predominant mechanism of rapid adaptation to miconazole in C. albicans, and the clinical relevance of tolerance deserves further investigations.
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Affiliation(s)
- Liangsheng Guo
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Lijun Zheng
- Department of Ultrasound Medicine, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Yubo Dong
- Department of Pharmacy, The 960th Hospital of PLA, Jinan, China
| | - Chen Wang
- Department of Pharmacy, The 960th Hospital of PLA, Jinan, China
| | - Huijie Deng
- Department of Pharmacy, The 960th Hospital of PLA, Jinan, China
| | - Zongjie Wang
- Department of Pharmacy, The 960th Hospital of PLA, Jinan, China
| | - Yi Xu
- Department of Pharmacy, The 960th Hospital of PLA, Jinan, China
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5
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Zhang ZH, Sun LL, Fu BQ, Deng J, Jia CL, Miao MX, Yang F, Cao YB, Yan TH. Aneuploidy underlies brefeldin A-induced antifungal drug resistance in Cryptococcus neoformans. Front Cell Infect Microbiol 2024; 14:1397724. [PMID: 38966251 PMCID: PMC11222406 DOI: 10.3389/fcimb.2024.1397724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Accepted: 05/17/2024] [Indexed: 07/06/2024] Open
Abstract
Cryptococcus neoformans is at the top of the list of "most wanted" human pathogens. Only three classes of antifungal drugs are available for the treatment of cryptococcosis. Studies on antifungal resistance mechanisms are limited to the investigation of how a particular antifungal drug induces resistance to a particular drug, and the impact of stresses other than antifungals on the development of antifungal resistance and even cross-resistance is largely unexplored. The endoplasmic reticulum (ER) is a ubiquitous subcellular organelle of eukaryotic cells. Brefeldin A (BFA) is a widely used chemical inducer of ER stress. Here, we found that both weak and strong selection by BFA caused aneuploidy formation in C. neoformans, mainly disomy of chromosome 1, chromosome 3, and chromosome 7. Disomy of chromosome 1 conferred cross-resistance to two classes of antifungal drugs: fluconazole and 5-flucytosine, as well as hypersensitivity to amphotericin B. However, drug resistance was unstable, due to the intrinsic instability of aneuploidy. We found overexpression of AFR1 on Chr1 and GEA2 on Chr3 phenocopied BFA resistance conferred by chromosome disomy. Overexpression of AFR1 also caused resistance to fluconazole and hypersensitivity to amphotericin B. Furthermore, a strain with a deletion of AFR1 failed to form chromosome 1 disomy upon BFA treatment. Transcriptome analysis indicated that chromosome 1 disomy simultaneously upregulated AFR1, ERG11, and other efflux and ERG genes. Thus, we posit that BFA has the potential to drive the rapid development of drug resistance and even cross-resistance in C. neoformans, with genome plasticity as the accomplice.
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Affiliation(s)
- Zhi-hui Zhang
- Institute of Vascular Disease, Shanghai TCM-Integrated Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Liu-liu Sun
- Department of Pharmacy, Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai, China
| | - Bu-qing Fu
- Laboratory Department, Jiangsu Province Hospital of Chinese Medicine, Nanjing, China
| | - Jie Deng
- Institute of Vascular Disease, Shanghai TCM-Integrated Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Cheng-lin Jia
- Institute of Vascular Disease, Shanghai TCM-Integrated Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Ming-xing Miao
- Department of Physiology and Pharmacology, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Feng Yang
- Institute of Vascular Disease, Shanghai TCM-Integrated Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
- Department of Pharmacy, Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai, China
| | - Yong-bing Cao
- Institute of Vascular Disease, Shanghai TCM-Integrated Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Tian-hua Yan
- Department of Physiology and Pharmacology, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
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6
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Chen XF, Zhang H, Liu LL, Guo LN, Liu WJ, Liu YL, Li DD, Zhao Y, Zhu RY, Li Y, Dai RC, Yu SY, Li J, Wang T, Dou HT, Xu YC. Genome-wide analysis of in vivo-evolved Candida auris reveals multidrug-resistance mechanisms. Mycopathologia 2024; 189:35. [PMID: 38637433 DOI: 10.1007/s11046-024-00832-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 01/17/2024] [Indexed: 04/20/2024]
Abstract
Candida auris, an emerging and multidrug-resistant fungal pathogen, has led to numerous outbreaks in China. While the resistance mechanisms against azole and amphotericin B have been studied, the development of drug resistance in this pathogen remains poorly understood, particularly in in vivo-generated drug-resistant strains. This study employed pathogen whole-genome sequencing to investigate the epidemiology and drug-resistance mutations of C. auris using 16 strains isolated from two patients. Identification was conducted through Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and antimicrobial susceptibilities were assessed using broth microdilution and Sensititre YeastOne YO10. Whole-genome sequencing revealed that all isolates belonged to the South Asian lineage, displaying genetic heterogeneity. Despite low genetic variability among patient isolates, notable mutations were identified, including Y132F in ERG11 and A585S in TAC1b, likely linked to increased fluconazole resistance. Strains from patient B also carried F214L in TAC1b, resulting in a consistent voriconazole minimum inhibitory concentration of 4 µg/mL across all isolates. Furthermore, a novel frameshift mutation in the SNG1 gene was observed in amphotericin B-resistant isolates compared to susceptible ones. Our findings suggest the potential transmission of C. auris and emphasize the need to explore variations related to antifungal resistance. This involves analyzing genomic mutations and karyotypes, especially in vivo, to compare sensitive and resistant strains. Further monitoring and validation efforts are crucial for a comprehensive understanding of the mechanisms of drug resistance in C. auris.
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Affiliation(s)
- Xin-Fei Chen
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
- Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases (BZ0447), Beijing, China
| | - Han Zhang
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
- Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases (BZ0447), Beijing, China
| | - Ling-Li Liu
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
- Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases (BZ0447), Beijing, China
- Graduate School, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Li-Na Guo
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
- Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases (BZ0447), Beijing, China
| | - Wen-Jing Liu
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
- Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases (BZ0447), Beijing, China
| | - Ya-Li Liu
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
- Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases (BZ0447), Beijing, China
| | - Ding-Ding Li
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
- Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases (BZ0447), Beijing, China
- Graduate School, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Ying Zhao
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
- Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases (BZ0447), Beijing, China
| | - Ren-Yuan Zhu
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
- Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases (BZ0447), Beijing, China
| | - Yi Li
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
- Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases (BZ0447), Beijing, China
- Graduate School, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Rong-Chen Dai
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
- Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases (BZ0447), Beijing, China
| | - Shu-Ying Yu
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
- Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases (BZ0447), Beijing, China
| | - Jin Li
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
- Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases (BZ0447), Beijing, China
| | - Tong Wang
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
- Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases (BZ0447), Beijing, China
- Graduate School, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Hong-Tao Dou
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China.
- Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases (BZ0447), Beijing, China.
| | - Ying-Chun Xu
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China.
- Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases (BZ0447), Beijing, China.
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7
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Lo TL, Wang Q, Nickson J, van Denderen BJW, Deveson Lucas D, Chai HX, Knott GJ, Weerasinghe H, Traven A. The C-terminal protein interaction domain of the chromatin reader Yaf9 is critical for pathogenesis of Candida albicans. mSphere 2024; 9:e0069623. [PMID: 38376217 PMCID: PMC10964406 DOI: 10.1128/msphere.00696-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 01/26/2024] [Indexed: 02/21/2024] Open
Abstract
Fungal infections cause a large health burden but are treated by only a handful of antifungal drug classes. Chromatin factors have emerged as possible targets for new antifungals. These targets include the reader proteins, which interact with posttranslationally modified histones to influence DNA transcription and repair. The YEATS domain is one such reader recognizing both crotonylated and acetylated histones. Here, we performed a detailed structure/function analysis of the Candida albicans YEATS domain reader Yaf9, a subunit of the NuA4 histone acetyltransferase and the SWR1 chromatin remodeling complex. We have previously demonstrated that the homozygous deletion mutant yaf9Δ/Δ displays growth defects and is avirulent in mice. Here we show that a YEATS domain mutant expected to inactivate Yaf9's chromatin binding does not display strong phenotypes in vitro, nor during infection of immune cells or in a mouse systemic infection model, with only a minor virulence reduction in vivo. In contrast to the YEATS domain mutation, deletion of the C-terminal domain of Yaf9, a protein-protein interaction module necessary for its interactions with SWR1 and NuA4, phenocopies the null mutant. This shows that the C-terminal domain is essential for Yaf9 roles in vitro and in vivo, including C. albicans virulence. Our study informs on the strategies for therapeutic targeting of Yaf9, showing that approaches taken for the mammalian YEATS domains by disrupting their chromatin binding might not be effective in C. albicans, and provides a foundation for studying YEATS proteins in human fungal pathogens.IMPORTANCEThe scarcity of available antifungal drugs and rising resistance demand the development of therapies with new modes of action. In this context, chromatin regulation may be a target for novel antifungal therapeutics. To realize this potential, we must better understand the roles of chromatin regulators in fungal pathogens. Toward this goal, here, we studied the YEATS domain chromatin reader Yaf9 in Candida albicans. Yaf9 uses the YEATS domain for chromatin binding and a C-terminal domain to interact with chromatin remodeling complexes. By constructing mutants in these domains and characterizing their phenotypes, our data indicate that the Yaf9 YEATS domain might not be a suitable therapeutic drug target. Instead, the Yaf9 C-terminal domain is critical for C. albicans virulence. Collectively, our study informs how a class of chromatin regulators performs their cellular and pathogenesis roles in C. albicans and reveals strategies to inhibit them.
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Affiliation(s)
- Tricia L. Lo
- Department of Biochemistry and Molecular Biology and the Infection Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
- Centre to Impact AMR, Monash University, Clayton, Australia
| | - Qi Wang
- Department of Biochemistry and Molecular Biology and the Infection Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Joshua Nickson
- Centre to Impact AMR, Monash University, Clayton, Australia
| | - Bryce J. W. van Denderen
- Department of Biochemistry and Molecular Biology and the Infection Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
- Centre to Impact AMR, Monash University, Clayton, Australia
| | | | - Her Xiang Chai
- Department of Biochemistry and Molecular Biology and the Infection Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Gavin J. Knott
- Department of Biochemistry and Molecular Biology and the Infection Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Harshini Weerasinghe
- Department of Biochemistry and Molecular Biology and the Infection Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
- Centre to Impact AMR, Monash University, Clayton, Australia
| | - Ana Traven
- Department of Biochemistry and Molecular Biology and the Infection Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
- Centre to Impact AMR, Monash University, Clayton, Australia
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8
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Amsri A, Pruksaphon K, Thammasit P, Nosanchuk JD, Youngchim S. Adaptation to an amoeba host drives selection of virulence-associated traits and genetic variation in saprotrophic Candida albicans. Front Cell Infect Microbiol 2024; 14:1367656. [PMID: 38550616 PMCID: PMC10976851 DOI: 10.3389/fcimb.2024.1367656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 02/27/2024] [Indexed: 04/02/2024] Open
Abstract
Amoebae are micropredators that play an important role in controlling fungal populations in ecosystems. However, the interaction between fungi and their amoebic predators suggests that the pressure from predatory selection can significantly influence the development of fungal virulence and evolutionary processes. Thus, the purpose of this study was to investigate the adaptation of saprotrophic Candida albicans strains during their interactions with Acanthamoeba castellanii. We conducted a comprehensive analysis of survival after co-culture by colony counting of the yeast cells and examining yeast cell phenotypic and genetic characteristics. Our results indicated that exposure to amoebae enhanced the survival capacity of environmental C. albicans and induced visible morphological alterations in C. albicans, particularly by an increase in filamentation. These observed phenotypic changes were closely related to concurrent genetic variations. Notably, mutations in genes encoding transcriptional repressors (TUP1 and SSN6), recognized for their negative regulation of filamentous growth, were exclusively identified in amoeba-passaged isolates, and absent in unexposed isolates. Furthermore, these adaptations increased the exposed isolates' fitness against various stressors, simultaneously enhancing virulence factors and demonstrating an increased ability to invade A549 lung human epithelial cells. These observations indicate that the sustained survival of C. albicans under ongoing amoebic predation involved a key role of mutation events in microevolution to modulate the ability of these isolates to change phenotype and increase their virulence factors, demonstrating an enhanced potential to survive in diverse environmental niches.
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Affiliation(s)
- Artid Amsri
- Office of Research Administration, Chiang Mai University, Chiang Mai, Thailand
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Kritsada Pruksaphon
- Department of Medical Technology, School of Allied Health Sciences, Walailak University, Nakhon Si Thammarat, Thailand
- Center of Excellence Research for Melioidosis and Microorganisms (CERMM), Walailak University, Nakhon Si Thammarat, Thailand
| | - Patcharin Thammasit
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Joshua D. Nosanchuk
- Department of Medicine (Division of Infectious Diseases), Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, United States
| | - Sirida Youngchim
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
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9
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Woodruff AL, Berman J, Anderson M. Strain background of Candida albicans interacts with SIR2 to alter phenotypic switching. MICROBIOLOGY (READING, ENGLAND) 2024; 170:001444. [PMID: 38446018 PMCID: PMC10999749 DOI: 10.1099/mic.0.001444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 02/15/2024] [Indexed: 03/07/2024]
Abstract
The genetic background between strains of a single species and within a single strain lineage can significantly impact the expression of biological traits. This genetic variation may also reshape epigenetic mechanisms of cell identity and environmental responses that are controlled by interconnected transcriptional networks and chromatin-modifying enzymes. Histone deacetylases, including sirtuins, are critical regulators of chromatin state and have been directly implicated in governing the phenotypic transition between the 'sterile' white state and the mating-competent opaque state in Candida albicans, a common fungal commensal and pathogen of humans. Here, we found that a previously ambiguous role for the sirtuin SIR2 in C. albicans phenotypic switching is likely linked to the genetic background of mutant strains produced in the RM lineage of SC5314. SIR2 mutants in a specific lineage of BWP17 displayed increased frequencies of switching to the opaque state compared to the wild-type. Loss of SIR2 in other SC5314-derived backgrounds, including newly constructed BWP17 sir2Δ/Δ mutants, failed to recapitulate the increased white-opaque switching frequencies observed in the original BWP17 sir2Δ/Δ mutant background. Whole-genome sequencing revealed the presence of multiple imbalanced chromosomes and large loss of heterozygosity tracts that likely interact with SIR2 to increase phenotypic switching in this BWP17 sir2Δ/Δ mutant lineage. These genomic changes are not found in other SC5314-derived sir2Δ/Δ mutants that do not display increased opaque cell formation. Thus, complex karyotypes can emerge during strain construction that modify mutant phenotypes and highlight the importance of validating strain background when interpreting phenotypes.
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Affiliation(s)
- Andrew L. Woodruff
- Department of Microbiology, The Ohio State University, Columbus, OH, 43210, USA
| | - Judith Berman
- Shmunis School of Biomedical and Cancer Research, The George S Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Matthew Anderson
- Department of Microbiology, The Ohio State University, Columbus, OH, 43210, USA
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, 43210, USA
- Department of Medical Genetics, Laboratory of Genetics, University of Wisconsin – Madison, Madison, WI, 53706, USA
- Center for Genomic Science Innovation, University of Wisconsin – Madison, Madison, WI, 53706, USA
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10
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Acosta-Zaldívar M, Qi W, Mishra A, Roy U, King WR, Patton-Vogt J, Anderson MZ, Köhler JR. Candida albicans' inorganic phosphate transport and evolutionary adaptation to phosphate scarcity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.29.577887. [PMID: 38352318 PMCID: PMC10862840 DOI: 10.1101/2024.01.29.577887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
Phosphorus is essential in all cells' structural, metabolic and regulatory functions. For fungal cells that import inorganic phosphate (Pi) up a steep concentration gradient, surface Pi transporters are critical capacitators of growth. Fungi must deploy Pi transporters that enable optimal Pi uptake in pH and Pi concentration ranges prevalent in their environments. Single, triple and quadruple mutants were used to characterize the four Pi transporters we identified for the human fungal pathogen Candida albicans, which must adapt to alkaline conditions during invasion of the host bloodstream and deep organs. A high-affinity Pi transporter, Pho84, was most efficient across the widest pH range while another, Pho89, showed high-affinity characteristics only within one pH unit of neutral. Two low-affinity Pi transporters, Pho87 and Fgr2, were active only in acidic conditions. Only Pho84 among the Pi transporters was clearly required in previously identified Pi-related functions including Target of Rapamycin Complex 1 signaling and hyphal growth. We used in vitro evolution and whole genome sequencing as an unbiased forward genetic approach to probe adaptation to prolonged Pi scarcity of two quadruple mutant lineages lacking all 4 Pi transporters. Lineage-specific genomic changes corresponded to divergent success of the two lineages in fitness recovery during Pi limitation. In this process, initial, large-scale genomic alterations like aneuploidies and loss of heterozygosity were eventually lost as populations presumably gained small-scale mutations. Severity of some phenotypes linked to Pi starvation, like cell wall stress hypersensitivity, decreased in parallel to evolving populations' fitness recovery in Pi scarcity, while that of others like membrane stress responses diverged from these fitness phenotypes. C. albicans therefore has diverse options to reconfigure Pi management during prolonged scarcity. Since Pi homeostasis differs substantially between fungi and humans, adaptive processes to Pi deprivation may harbor small-molecule targets that impact fungal growth and virulence.
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Affiliation(s)
- Maikel Acosta-Zaldívar
- Division of Infectious Diseases, Boston Children’s Hospital/Harvard Medical School, Boston, MA 02115, USA
- Current affiliation: Planasa, Valladolid, Spain
| | - Wanjun Qi
- Division of Infectious Diseases, Boston Children’s Hospital/Harvard Medical School, Boston, MA 02115, USA
| | - Abhishek Mishra
- Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison, WI
| | - Udita Roy
- Division of Infectious Diseases, Boston Children’s Hospital/Harvard Medical School, Boston, MA 02115, USA
| | - William R. King
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Jana Patton-Vogt
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Matthew Z. Anderson
- Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison, WI
- Department of Medical Genetics, Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI
| | - Julia R. Köhler
- Division of Infectious Diseases, Boston Children’s Hospital/Harvard Medical School, Boston, MA 02115, USA
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11
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Smukowski Heil C. Loss of Heterozygosity and Its Importance in Evolution. J Mol Evol 2023; 91:369-377. [PMID: 36752826 PMCID: PMC10276065 DOI: 10.1007/s00239-022-10088-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 12/23/2022] [Indexed: 02/09/2023]
Abstract
Loss of heterozygosity (LOH) is a mitotic recombination event that converts heterozygous loci to homozygous loci. This mutation event is widespread in organisms that have asexual reproduction like budding yeasts, and is also an important and frequent mutation event in tumorigenesis. Mutation accumulation studies have demonstrated that LOH occurs at a rate higher than the point mutation rate, and can impact large portions of the genome. Laboratory evolution experiments of heterozygous yeasts have revealed that LOH often unmasks beneficial recessive alleles that can confer large fitness advantages. Here, I highlight advances in understanding dominance, fitness, and phenotypes in laboratory evolved heterozygous yeast strains. I discuss best practices for detecting LOH in intraspecific and interspecific evolved clones and populations. Utilizing heterozygous strain backgrounds in laboratory evolution experiments offers an opportunity to advance our understanding of this important mutation type in shaping adaptation and genome evolution in wild, domesticated, and clinical populations.
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Affiliation(s)
- Caiti Smukowski Heil
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA.
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12
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Wangsanut T, Arnold SJY, Jilani SZ, Marzec S, Monsour RC, Rolfes RJ. Grf10 regulates the response to copper, iron, and phosphate in Candida albicans. G3 (BETHESDA, MD.) 2023; 13:jkad070. [PMID: 36966423 PMCID: PMC10234403 DOI: 10.1093/g3journal/jkad070] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 01/19/2023] [Accepted: 02/27/2023] [Indexed: 03/27/2023]
Abstract
The pathogenic yeast, Candida albicans, and other microbes must be able to handle drastic changes in nutrient availability within the human host. Copper, iron, and phosphate are essential micronutrients for microbes that are sequestered by the human host as nutritional immunity; yet high copper levels are employed by macrophages to induce toxic oxidative stress. Grf10 is a transcription factor important for regulating genes involved in morphogenesis (filamentation, chlamydospore formation) and metabolism (adenylate biosynthesis, 1-carbon metabolism). The grf10Δ mutant exhibited resistance to excess copper in a gene dosage-dependent manner but grew the same as the wild type in response to other metals (calcium, cobalt, iron, manganese, and zinc). Point mutations in the conserved residues D302 and E305, within a protein interaction region, conferred resistance to high copper and induced hyphal formation similar to strains with the null allele. The grf10Δ mutant misregulated genes involved with copper, iron, and phosphate uptake in YPD medium and mounted a normal transcriptional response to high copper. The mutant accumulated lower levels of magnesium and phosphorus, suggesting that copper resistance is linked to phosphate metabolism. Our results highlight new roles for Grf10 in copper and phosphate homeostasis in C. albicans and underscore the fundamental role of Grf10 in connecting these with cell survival.
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Affiliation(s)
- Tanaporn Wangsanut
- Department of Biology, Georgetown University, Washington, DC 20057, USA
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Sylvia J Y Arnold
- Department of Biology, Georgetown University, Washington, DC 20057, USA
| | - Safia Z Jilani
- Department of Chemistry, Georgetown University, Washington, DC 20057, USA
- Center for Sustainable Nanotechnology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Sarah Marzec
- Department of Biology, Georgetown University, Washington, DC 20057, USA
| | - Robert C Monsour
- Department of Biology, Georgetown University, Washington, DC 20057, USA
- Morsani College of Medicine, University of South Florida, Tampa, FL 33602, USA
| | - Ronda J Rolfes
- Department of Biology, Georgetown University, Washington, DC 20057, USA
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13
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Antifungal Tolerance and Resistance Emerge at Distinct Drug Concentrations and Rely upon Different Aneuploid Chromosomes. mBio 2023; 14:e0022723. [PMID: 36877011 PMCID: PMC10127634 DOI: 10.1128/mbio.00227-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023] Open
Abstract
Antifungal drug tolerance is a response distinct from resistance, in which cells grow slowly above the MIC. Here, we found that the majority (69.2%) of 133 Candida albicans clinical isolates, including standard lab strain SC5314, exhibited temperature-enhanced tolerance at 37°C and 39°C, and were not tolerant at 30°C. Other isolates were either always tolerant (23.3%) or never tolerant (7.5%) at these three temperatures, suggesting that tolerance requires different physiological processes in different isolates. At supra-MIC fluconazole concentrations (8 to 128 μg/mL), tolerant colonies emerged rapidly at a frequency of ~10-3. In liquid passages over a broader range of fluconazole concentrations (0.25 to 128 μg/mL), tolerance emerged rapidly (within one passage) at supra-MICs. In contrast, resistance appeared at sub-MICs after 5 or more passages. Of 155 adaptors that evolved higher tolerance, all carried one of several recurrent aneuploid chromosomes, often including chromosome R, alone or in combination with other chromosomes. Furthermore, loss of these recurrent aneuploidies was associated with a loss of acquired tolerance, indicating that specific aneuploidies confer fluconazole tolerance. Thus, genetic background and physiology and the degree of drug stress (above or below the MIC) influence the evolutionary trajectories and dynamics with which antifungal drug resistance or tolerance emerges. IMPORTANCE Antifungal drug tolerance differs from drug resistance: tolerant cells grow slowly in drug, while resistant cells usually grow well, due to mutations in a few known genes. More than half of Candida albicans clinical isolates have higher tolerance at body temperature than they do at the lower temperatures used for most lab experiments. This implies that different isolates achieve drug tolerance via several cellular processes. When we evolved different strains at a range of high drug concentrations above inhibitory levels, tolerance emerged rapidly and at high frequency (one in 1,000 cells) while resistance appeared only later at very low drug concentrations. An extra copy of all or part of chromosome R was associated with tolerance, while point mutations or different aneuploidies were seen with resistance. Thus, genetic background and physiology, temperature, and drug concentration all influence how drug tolerance or resistance evolves.
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14
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Todd RT, Selmecki A. Copy Number Variation and Allele Ratio Analysis in Candida albicans Using Whole Genome Sequencing Data. Methods Mol Biol 2023; 2658:105-125. [PMID: 37024698 PMCID: PMC10676714 DOI: 10.1007/978-1-0716-3155-3_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
Whole genome sequencing of human fungal pathogens has revolutionized the speed and accuracy in which sequence variants that cause antifungal resistance can be identified. Genome rearrangements resulting in copy number variation (CNV) are a significant source of acquired antifungal drug resistance across diverse fungal species. Some CNVs are transient in nature, while other CNVs are stable and well tolerated even in the absence of antifungal drugs. By visualizing whole genome sequencing read depth as a function of genomic location, CNVs and CNV breakpoints (genomic positions where the copy number changes occur relative to the rest of the genome) are rapidly identified. A similar analysis can be used to visualize allele ratio changes that occur across the genomes of heterozygous fungal species, both in the presence and absence of CNVs. This protocol walks through the bioinformatic analysis of CNVs and allele ratios utilizing free, open-source visualization tools. We provide code to use with an example dataset (matched antifungal drug-sensitive and drug-resistant Candida albicans isolates) and notes on how to expand this protocol to other fungal genomes.
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Affiliation(s)
- Robert T Todd
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Anna Selmecki
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, USA.
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15
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Alastruey-Izquierdo A, Martín-Galiano AJ. The challenges of the genome-based identification of antifungal resistance in the clinical routine. Front Microbiol 2023; 14:1134755. [PMID: 37152754 PMCID: PMC10157239 DOI: 10.3389/fmicb.2023.1134755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 04/05/2023] [Indexed: 05/09/2023] Open
Abstract
The increasing number of chronic and life-threatening infections caused by antimicrobial resistant fungal isolates is of critical concern. Low DNA sequencing cost may facilitate the identification of the genomic profile leading to resistance, the resistome, to rationally optimize the design of antifungal therapies. However, compared to bacteria, initiatives for resistome detection in eukaryotic pathogens are underdeveloped. Firstly, reported mutations in antifungal targets leading to reduced susceptibility must be extensively collected from the literature to generate comprehensive databases. This information should be complemented with specific laboratory screenings to detect the highest number possible of relevant genetic changes in primary targets and associations between resistance and other genomic markers. Strikingly, some drug resistant strains experience high-level genetic changes such as ploidy variation as much as duplications and reorganizations of specific chromosomes. Such variations involve allelic dominance, gene dosage increments and target expression regime effects that should be explicitly parameterized in antifungal resistome prediction algorithms. Clinical data indicate that predictors need to consider the precise pathogen species and drug levels of detail, instead of just genus and drug class. The concomitant needs for mutation accuracy and assembly quality assurance suggest hybrid sequencing approaches involving third-generation methods will be utilized. Moreover, fatal fast infections, like fungemia and meningitis, will further require both sequencing and analysis facilities are available in-house. Altogether, the complex nature of antifungal resistance demands extensive sequencing, data acquisition and processing, bioinformatic analysis pipelines, and standard protocols to be accomplished prior to genome-based protocols are applied in the clinical setting.
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Affiliation(s)
- Ana Alastruey-Izquierdo
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Madrid, Spain
- Center for Biomedical Research in Network in Infectious Diseases (CIBERINFEC-CB21/13/00105), Instituto de Salud Carlos III, Madrid, Spain
- *Correspondence: Ana Alastruey-Izquierdo,
| | - Antonio J. Martín-Galiano
- Core Scientific and Technical Units, Instituto de Salud Carlos III, Madrid, Spain
- Antonio J. Martín-Galiano,
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16
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Patel SK, Sahu SR, Utkalaja BG, Bose S, Acharya N. Pol32, an accessory subunit of DNA polymerase delta, plays an essential role in genome stability and pathogenesis of Candida albicans. Gut Microbes 2023; 15:2163840. [PMID: 36601868 PMCID: PMC9828637 DOI: 10.1080/19490976.2022.2163840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Candida albicans is a pathobiont that inflicts serious bloodstream fungal infections in individuals with compromised immunity and gut dysbiosis. Genomic diversity in the form of copy number alteration, ploidy variation, and loss of heterozygosity as an adaptive mechanism to adverse environments is frequently observed in C. albicans. Such genomic variations also confer a varied degree of fungal virulence and drug resistance, yet the factors propelling these are not completely understood. DNA polymerase delta (Polδ) is an essential replicative DNA polymerase in the eukaryotic cell and is yet to be characterized in C. albicans. Therefore, this study was designed to gain insights into the role of Polδ, especially its non-essential subunit Pol32, in the genome plasticity and life cycle of C. albicans. PCNA, the DNA clamp, recruits Polδ to the replication fork for processive DNA replication. Unlike in Saccharomyces cerevisiae, the PCNA interaction protein (PIP) motif of CaPol32 is critical for Polδ's activity during DNA replication. Our comparative genetic analyses and whole-genome sequencing of POL32 proficient and deficient C. albicans cells revealed a critical role of Pol32 in DNA replication, cell cycle progression, and genome stability as SNPs, indels, and repeat variations were largely accumulated in pol32 null strain. The loss of pol32 in C. albicans conferred cell wall deformity; Hsp90 mediated azoles resistance, biofilm development, and a complete attenuation of virulence in an animal model of systemic candidiasis. Thus, although Pol32 is dispensable for cell survival, its function is essential for C. albicans pathogenesis; and we discuss its translational implications in antifungal drugs and whole-cell vaccine development.
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Affiliation(s)
- Shraddheya Kumar Patel
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India,Regional center of Biotechnology, Faridabad, India
| | - Satya Ranjan Sahu
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India,Regional center of Biotechnology, Faridabad, India
| | - Bhabasha Gyanadeep Utkalaja
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India,Regional center of Biotechnology, Faridabad, India
| | - Swagata Bose
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India,School of Biotechnology, Kalinga Institute of Industrial Technology, Bhubaneswar, India
| | - Narottam Acharya
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India,CONTACT Narottam Acharya ; Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar751023, India
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17
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Sun LL, Li H, Yan TH, Cao YB, Jiang YY, Yang F. Aneuploidy enables cross-tolerance to unrelated antifungal drugs in Candida parapsilosis. Front Microbiol 2023; 14:1137083. [PMID: 37113223 PMCID: PMC10126355 DOI: 10.3389/fmicb.2023.1137083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 03/17/2023] [Indexed: 04/29/2023] Open
Abstract
Candida parapsilosis is an emerging major human fungal pathogen. Echinocandins are first-line antifungal drugs for the treatment of invasive Candida infections. In clinical isolates, tolerance to echinocandins in Candida species is mostly due to point mutations of FKS genes, which encode the target protein of echinocandins. However, here, we found chromosome 5 trisomy was the major mechanism of adaptation to the echinocandin drug caspofungin, and FKS mutations were rare events. Chromosome 5 trisomy conferred tolerance to echinocandin drugs caspofungin and micafungin and cross-tolerance to 5-flucytosine, another class of antifungal drugs. The inherent instability of aneuploidy caused unstable drug tolerance. Tolerance to echinocandins might be due to increased copy number and expression of CHS7, which encodes chitin synthase. Although copy number of chitinase genes CHT3 and CHT4 was also increased to the trisomic level, the expression was buffered to the disomic level. Tolerance to 5-flucytosine might be due to the decreased expression of FUR1. Therefore, the pleiotropic effect of aneuploidy on antifungal tolerance was due to the simultaneous regulation of genes on the aneuploid chromosome and genes on euploid chromosomes. In summary, aneuploidy provides a rapid and reversible mechanism of drug tolerance and cross-tolerance in C. parapsilosis.
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Affiliation(s)
- Liu-liu Sun
- Department of Pharmacy, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
- Department of Physiology and Pharmacology, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Hao Li
- Department of Pharmacy, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
- Department of Physiology and Pharmacology, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Tian-hua Yan
- Department of Physiology and Pharmacology, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Yong-bing Cao
- Department of Vascular Diseases, Shanghai TCM-Integrated Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Yuan-ying Jiang
- Department of Pharmacy, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
- Yuan-ying Jiang
| | - Feng Yang
- Department of Pharmacy, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
- *Correspondence: Feng Yang
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18
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Directed Evolution Detects Supernumerary Centric Chromosomes Conferring Resistance to Azoles in Candida auris. mBio 2022; 13:e0305222. [PMID: 36445083 PMCID: PMC9765433 DOI: 10.1128/mbio.03052-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Candida auris exhibits resistance to multiple antifungal drug classes and sterilization agents, posing threats to the immunocompromised worldwide. Among the four major geographical clades, the East Asian clade 2 isolates of C. auris are mostly drug susceptible. In this study, we experimentally evolved one such drug-susceptible isolate for multiple generations in the presence of the antifungal compound fluconazole and analyzed changes in the karyotype, DNA sequence, and gene expression profiles in three evolved drug-resistant isolates. Next-generation sequencing and electrophoretic karyotyping confirm the presence of segmental aneuploidy as supernumerary chromosomes originating from centromere-inclusive chromosomal duplication events in two such cases. A 638-kb region and a 675-kb region, both of which originated from chromosome 5 and contained its centromere region, are instances of supernumerary chromosome formation identified in two evolved fluconazole-resistant isolates. Loss of the supernumerary chromosomes from the drug-resistant isolates results in a complete reversal of fluconazole susceptibility. Transcriptome analysis of the third isolate identified overexpression of drug efflux pumps as a possible non-aneuploidy-driven mechanism of drug resistance. Together, this study reveals how both aneuploidy-driven and aneuploidy-independent mechanisms may operate in parallel in an evolving population of C. auris in the presence of an antifungal drug, in spite of starting from the same strain grown under similar conditions, to attain various levels of fluconazole resistance. IMPORTANCE Fungal pathogens develop drug resistance through multiple pathways by acquiring gene mutations, increasing the copy number of genes, or altering gene expression. In this study, we attempt to understand the mechanisms of drug resistance in the recently emerged superbug, C. auris. One approach to studying this aspect is identifying various mechanisms operating in drug-resistant clinical isolates. An alternative approach is to evolve a drug-susceptible isolate in the presence of an antifungal compound and trace the changes that result in drug resistance. Here, we evolve a drug-susceptible isolate of C. auris in the laboratory in the presence of a widely used antifungal compound, fluconazole. In addition to the already known changes like overexpression of drug efflux pumps, this study identifies a novel mechanism of azole resistance by the emergence of additional chromosomes through segmental duplication of chromosomal regions, including centromeres. The centric supernumerary chromosome helps stable amplification of a set of genes with an extra copy to confer fluconazole resistance.
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19
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Chen XF, Zhang H, Jia XM, Cao J, Li L, Hu XL, Li N, Xiao YL, Xia F, Ye LY, Hu QF, Wu XL, Ning LP, Hsueh PR, Fan X, Yu SY, Huang JJ, Xie XL, Yang WH, Li YX, Zhang G, Zhang JJ, Duan SM, Kang W, Wang T, Li J, Xiao M, Hou X, Xu YC. Antifungal susceptibility profiles and drug resistance mechanisms of clinical Candida duobushaemulonii isolates from China. Front Microbiol 2022; 13:1001845. [PMID: 36545202 PMCID: PMC9760970 DOI: 10.3389/fmicb.2022.1001845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Accepted: 08/22/2022] [Indexed: 12/12/2022] Open
Abstract
Candida duobushaemulonii, type II Candida haemulonii complex, is closely related to Candida auris and capable of causing invasive and non-invasive infections in humans. Eleven strains of C. duobushaemulonii were collected from China Hospital Invasive Fungal Surveillance Net (CHIF-NET) and identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF), VITEK 2 Yeast Identification Card (YST), and internal transcribed spacer (ITS) sequencing. Whole genome sequencing of C. duobushaemulonii was done to determine their genotypes. Furthermore, C. duobushaemulonii strains were tested by Sensititre YeastOne™ and Clinical and Laboratory Institute (CLSI) broth microdilution panel for antifungal susceptibility. Three C. duobushaemulonii could not be identified by VITEK 2. All 11 isolates had high minimum inhibitory concentrations (MICs) to amphotericin B more than 2 μg/ml. One isolate showed a high MIC value of ≥64 μg/ml to 5-flucytosine. All isolates were wild type (WT) for triazoles and echinocandins. FUR1 variation may result in C. duobushaemulonii with high MIC to 5-flucytosine. Candida duobushaemulonii mainly infects patients with weakened immunity, and the amphotericin B resistance of these isolates might represent a challenge to clinical treatment.
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Affiliation(s)
- Xin-Fei Chen
- 1Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China,2Graduate School, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China,3Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, China
| | - Han Zhang
- 1Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China,3Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, China
| | - Xin-Miao Jia
- 3Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, China,4Medical Research Center, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Jin Cao
- 5Jinling Hospital Institute of Clinical Laboratory Science, School of Medicine, Nanjing University, Nanjing, Jiangsu, China
| | - Li Li
- 6Department of Dermatology, Hua Shan Hospital, Fudan University, Shanghai, China
| | - Xin-Lan Hu
- 7Department of Laboratory Medicine, Fujian Provincial Hospital, Fuzhou, China
| | - Ning Li
- 7Department of Laboratory Medicine, Fujian Provincial Hospital, Fuzhou, China
| | - Yu-Ling Xiao
- 8Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Fei Xia
- 9Department of Laboratory Medicine, Ruian People's Hospital, Wenzhou, China
| | - Li-Yan Ye
- 10Department of Laboratory Medicine, The First Medicine Center, Chinese PLA General Hospital, Beijing, China
| | - Qing-Feng Hu
- 11Department of Laboratory Medicine, Zhejiang Provincial People's Hospital, Hangzhou, China
| | - Xiao-Li Wu
- 12Department of Laboratory Medicine, The People’s Hospital of Liaoning Province, Shenyang, China
| | - Li-Ping Ning
- 13Department of Laboratory Medicine, No.908 Hospital of Joint Logistics Support Force, Nanchang, China
| | - Po-Ren Hsueh
- 14Department of Laboratory Medicine and Internal Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan,15Department of Laboratory Medicine and Internal Medicine, China Medical University Hospital, China Medical University, Taichung, Taiwan
| | - Xin Fan
- 16Department of Infectious Diseases and Clinical Microbiology, Beijing Institute of Respiratory Medicine and Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China
| | - Shu-Ying Yu
- 1Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China,3Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, China
| | - Jing-Jing Huang
- 1Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China,2Graduate School, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China,3Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, China
| | - Xiu-Li Xie
- 1Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China,3Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, China
| | - Wen-Hang Yang
- 1Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China,2Graduate School, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China,3Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, China
| | - Ying-Xing Li
- 3Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, China,4Medical Research Center, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Ge Zhang
- 1Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China,3Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, China
| | - Jing-Jia Zhang
- 1Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China,3Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, China
| | - Si-Meng Duan
- 1Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China,3Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, China
| | - Wei Kang
- 1Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China,3Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, China
| | - Tong Wang
- 1Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China,3Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, China
| | - Jin Li
- 1Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China,3Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, China
| | - Meng Xiao
- 1Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China,3Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, China
| | - Xin Hou
- 17Department of Laboratory Medicine, Peking University Third Hospital, Beijing, China,Xin Hou,
| | - Ying-Chun Xu
- 1Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China,3Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, China,*Correspondence: Ying-Chun Xu,
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20
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Avramovska O, Smith AC, Rego E, Hickman MA. Tetraploidy accelerates adaptation under drug selection in a fungal pathogen. FRONTIERS IN FUNGAL BIOLOGY 2022; 3:984377. [PMID: 37746235 PMCID: PMC10512305 DOI: 10.3389/ffunb.2022.984377] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 09/06/2022] [Indexed: 09/26/2023]
Abstract
Baseline ploidy significantly impacts evolutionary trajectories and, specifically, tetraploidy is associated with higher rates of adaptation relative to haploidy and diploidy. While the majority of experimental evolution studies investigating ploidy use the budding yeast Saccharomyces cerivisiae, the fungal pathogen Candida albicans is a powerful system to investigate ploidy dynamics, particularly in the context of acquiring antifungal drug resistance. C. albicans laboratory and clinical strains are predominantly diploid, but have been isolated as haploid and polyploid. Here, we evolved diploid and tetraploid C. albicans for ~60 days in the antifungal drug caspofungin. Tetraploid-evolved lines adapted faster than diploid-evolved lines and reached higher levels of caspofungin resistance. While diploid-evolved lines generally maintained their initial genome size, tetraploid-evolved lines rapidly underwent genome-size reductions and did so prior to caspofungin adaptation. While clinical resistance was largely due to mutations in FKS1, these mutations were caused by substitutions in diploid, and indels in tetraploid isolates. Furthermore, fitness costs in the absence of drug selection were significantly less in tetraploid-evolved lines compared to the diploid-evolved lines. Taken together, this work supports a model of adaptation in which the tetraploid state is transient but its ability to rapidly transition ploidy states improves adaptive outcomes and may drive drug resistance in fungal pathogens.
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Affiliation(s)
- Ognenka Avramovska
- Department of Biology, Emory University, Atlanta, GA, United States
- Department of Genetics, Harvard Medical School, Boston, MA, United States
| | - Amanda C. Smith
- Department of Biology, Emory University, Atlanta, GA, United States
- Division of Viral Disease, CDC Foundation, Atlanta, GA, United States
| | - Emily Rego
- Department of Biology, Emory University, Atlanta, GA, United States
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21
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Kukurudz RJ, Chapel M, Wonitowy Q, Adamu Bukari AR, Sidney B, Sierhuis R, Gerstein AC. Acquisition of cross-azole tolerance and aneuploidy in Candida albicans strains evolved to posaconazole. G3 (BETHESDA, MD.) 2022; 12:jkac156. [PMID: 35881695 PMCID: PMC9434289 DOI: 10.1093/g3journal/jkac156] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 06/13/2022] [Indexed: 12/30/2022]
Abstract
A number of in vitro studies have examined the acquisition of drug resistance to the triazole fluconazole, a first-line treatment for many Candida infections. Much less is known about posaconazole, a newer triazole. We conducted the first in vitro experimental evolution of replicates from 8 diverse strains of Candida albicans in a high level of the fungistatic drug posaconazole. Approximately half of the 132 evolved replicates survived 50 generations of evolution, biased toward some of the strain backgrounds. We found that although increases in drug resistance were rare, increases in drug tolerance (the slow growth of a subpopulation of cells in a level of drug above the resistance level) were common across strains. We also found that adaptation to posaconazole resulted in widespread cross-tolerance to other azole drugs. Widespread aneuploidy was observed in evolved replicates from some strain backgrounds. Trisomy of at least one of chromosomes 3, 6, and R was identified in 11 of 12 whole-genome sequenced evolved SC5314 replicates. These findings document rampant evolved cross-tolerance among triazoles and highlight that increases in drug tolerance can evolve independently of drug resistance in a diversity of C. albicans strain backgrounds.
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Affiliation(s)
- Rebekah J Kukurudz
- Department of Microbiology, The University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Madison Chapel
- Department of Microbiology, The University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Quinn Wonitowy
- Department of Microbiology, The University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | | | - Brooke Sidney
- Department of Microbiology, The University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Riley Sierhuis
- Department of Microbiology, The University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Aleeza C Gerstein
- Department of Microbiology, The University of Manitoba, Winnipeg, MB R3T 2N2, Canada
- Department of Statistics, The University of Manitoba, Winnipeg, MB R3T 2N2, Canada
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22
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Schikora-Tamarit MÀ, Gabaldón T. PerSVade: personalized structural variant detection in any species of interest. Genome Biol 2022; 23:175. [PMID: 35974382 PMCID: PMC9380391 DOI: 10.1186/s13059-022-02737-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 07/22/2022] [Indexed: 11/12/2022] Open
Abstract
Structural variants (SVs) underlie genomic variation but are often overlooked due to difficult detection from short reads. Most algorithms have been tested on humans, and it remains unclear how applicable they are in other organisms. To solve this, we develop perSVade (personalized structural variation detection), a sample-tailored pipeline that provides optimally called SVs and their inferred accuracy, as well as small and copy number variants. PerSVade increases SV calling accuracy on a benchmark of six eukaryotes. We find no universal set of optimal parameters, underscoring the need for sample-specific parameter optimization. PerSVade will facilitate SV detection and study across diverse organisms.
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Affiliation(s)
- Miquel Àngel Schikora-Tamarit
- Barcelona Supercomputing Centre (BSC-CNS), Plaça Eusebi Güell, 1-3, 08034, Barcelona, Spain
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028, Barcelona, Spain
| | - Toni Gabaldón
- Barcelona Supercomputing Centre (BSC-CNS), Plaça Eusebi Güell, 1-3, 08034, Barcelona, Spain.
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028, Barcelona, Spain.
- Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain.
- Centro Investigación Biomédica En Red de Enfermedades Infecciosas, Barcelona, Spain.
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23
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Genomic Diversity across Candida auris Clinical Isolates Shapes Rapid Development of Antifungal Resistance
In Vitro
and
In Vivo. mBio 2022; 13:e0084222. [PMID: 35862787 PMCID: PMC9426540 DOI: 10.1128/mbio.00842-22] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Antifungal drug resistance and tolerance pose a serious threat to global public health. In the human fungal pathogen, Candida auris, resistance to triazole, polyene, and echinocandin antifungals is rising, resulting in multidrug resistant isolates. Here, we use genome analysis and in vitro evolution of 17 new clinical isolates of C. auris from clades I and IV to determine how quickly resistance mutations arise, the stability of resistance in the absence of drug, and the impact of genetic background on evolutionary trajectories. We evolved each isolate in the absence of drug as well as in low and high concentrations of fluconazole. In just three passages, we observed genomic and phenotypic changes including karyotype alterations, aneuploidy, acquisition of point mutations, and increases in MIC values within the populations. Fluconazole resistance was stable in the absence of drug, indicating little to no fitness cost associated with resistance. Importantly, two isolates substantially increased resistance to ≥256 μg/mL fluconazole. Multiple evolutionary pathways and mutations associated with increased fluconazole resistance occurred simultaneously within the same population. Strikingly, the subtelomeric regions of C. auris were highly dynamic as deletion of multiple genes near the subtelomeres occurred during the three passages in several populations. Finally, we discovered a mutator phenotype in a clinical isolate of C. auris. This isolate had elevated mutation rates compared to other isolates and acquired substantial resistance during evolution in vitro and in vivo supporting that the genetic background of clinical isolates can have a significant effect on evolutionary potential.
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24
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Zhou Z, Zhu C, Ip M, Liu M, Zhu Z, Liu R, Li X, Zeng L, Wu W. Molecular Epidemiology and Antifungal Resistance of Cryptococcus neoformans From Human Immunodeficiency Virus-Negative and Human Immunodeficiency Virus-Positive Patients in Eastern China. Front Microbiol 2022; 13:942940. [PMID: 35865921 PMCID: PMC9294546 DOI: 10.3389/fmicb.2022.942940] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 06/13/2022] [Indexed: 11/17/2022] Open
Abstract
Cryptococcosis is an opportunistic and potentially lethal infection caused by Cryptococcus neoformans and Cryptococcus gattii complex, which affects both immunocompromised and immunocompetent people, and it has become a major public health concern worldwide. In this study, we characterized the molecular epidemiology and antifungal susceptibility of 133 C. neoformans isolates from East China Invasive Fungal Infection Group (ECIFIG), 2017–2020. Isolates were identified to species level by matrix-assisted laser desorption ionization-time of flight mass spectrometry and confirmed by IGS1 sequencing. Whole-genome sequencing (WGS) was conducted on three multidrug-resistant isolates. Among the 133 strains, 61 (45.86%) were isolated from HIV-positive patients and 72 (54.16%) were isolated from HIV-negative patients. In total, C. neoformans var. grubii accounted for 97.74% (130/133), while C. neoformans var. neoformans was rare (2.06%, 3/133). The strains were further classified into nine sequence types (STs) dominated by ST5 (90.23%, 120/133) with low genetic diversity. No association was observed between STs and HIV status. All strains were wild type to voriconazole, while high antifungal minimal inhibitory concentrations (MICs) above the epidemiological cutoff values (ECVs) were observed in C. neoformans strains, and more than half of isolates were non-wild-type to amphotericin B (89.15%, 109/133). Eight isolates were resistant to fluconazole, and eight isolates were non-wild type to 5-fluorocytosine. Furthermore, WGS has verified the novel mutations of FUR1 in 5-fluorocytosine-resistant strains. In one isolate, aneuploidy of chromosome 1 with G484S mutation of ERG11 was observed, inducing high-level resistance (MIC: 32 μg/ml) to fluconazole. In general, our data showed that there was no significant difference between HIV-positive and HIV-negative patients on STs, and we elucidate the resistant mechanisms of C. neoformans from different perspectives. It is important for clinical therapy and drug usage in the future.
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Affiliation(s)
- Ziyi Zhou
- Department of Laboratory Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Chendi Zhu
- Department of Microbiology, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Margaret Ip
- Department of Microbiology, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Manjiao Liu
- State Key Laboratory of Translational Medicine and Innovative Drug Development, Jiangsu Simcere Diagnostics Co., Ltd., Nanjing, China
| | - Zhaoqin Zhu
- Shanghai Public Health Clinical Center, Shanghai, China
| | - Ryon Liu
- State Key Laboratory of Translational Medicine and Innovative Drug Development, Jiangsu Simcere Diagnostics Co., Ltd., Nanjing, China
| | - Xiaomin Li
- State Key Laboratory of Translational Medicine and Innovative Drug Development, Jiangsu Simcere Diagnostics Co., Ltd., Nanjing, China
| | - Lingbing Zeng
- Department of Laboratory Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, China
- *Correspondence: Lingbing Zeng,
| | - Wenjuan Wu
- Department of Laboratory Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
- Wenjuan Wu,
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25
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Schikora-Tamarit MÀ, Gabaldón T. Using genomics to understand the mechanisms of virulence and drug resistance in fungal pathogens. Biochem Soc Trans 2022; 50:1259-1268. [PMID: 35713390 PMCID: PMC9246328 DOI: 10.1042/bst20211123] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 05/27/2022] [Accepted: 06/06/2022] [Indexed: 02/06/2023]
Abstract
Fungal pathogens pose an increasingly worrying threat to human health, food security and ecosystem diversity. To tackle fungal infections and improve current diagnostic and therapeutic tools it is necessary to understand virulence and antifungal drug resistance mechanisms in diverse species. Recent advances in genomics approaches have provided a suitable framework to understand these phenotypes, which ultimately depend on genetically encoded determinants. In this work, we review how the study of genome sequences has been key to ascertain the bases of virulence and drug resistance traits. We focus on the contribution of comparative genomics, population genomics and directed evolution studies. In addition, we discuss how different types of genomic mutations (small or structural variants) contribute to intraspecific differences in virulence or drug resistance. Finally, we review current challenges in the field and anticipate future directions to solve them. In summary, this work provides a short overview of how genomics can be used to understand virulence and drug resistance in fungal pathogens.
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Affiliation(s)
- Miquel Àngel Schikora-Tamarit
- Barcelona Supercomputing Centre (BSC-CNS), Plaça Eusebi Güell, 1-3, 08034 Barcelona, Spain
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10, 08028 Barcelona, Spain
| | - Toni Gabaldón
- Barcelona Supercomputing Centre (BSC-CNS), Plaça Eusebi Güell, 1-3, 08034 Barcelona, Spain
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10, 08028 Barcelona, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain
- Centro de Investigación Biomédica En Red de Enfermedades Infecciosas, Barcelona, Spain
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26
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Host defense mechanisms induce genome instability leading to rapid evolution in an opportunistic fungal pathogen. Infect Immun 2021; 90:e0032821. [PMID: 34898249 DOI: 10.1128/iai.00328-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The ability to generate genetic variation facilitates rapid adaptation in stressful environments. The opportunistic fungal pathogen Candida albicans frequently undergoes large-scale genomic changes, including aneuploidy and loss-of heterozygosity (LOH), following exposure to host environments. However, the specific host factors inducing C. albicans genome instability remain largely unknown. Here, we leveraged the genetic tractability of nematode hosts to investigate whether innate immune components, including antimicrobial peptides (AMPs) and reactive oxygen species (ROS), induced host-associated C. albicans genome instability. C. albicans associated with immunocompetent hosts carried multiple large-scale genomic changes including LOH, whole chromosome, and segmental aneuploidies. In contrast, C. albicans associated with immunocompromised hosts deficient in AMPs or ROS production had reduced LOH frequencies and fewer, if any, additional genomic changes. To evaluate if extensive host-induced genomic changes had long-term consequences for C. albicans adaptation, we experimentally evolved C. albicans in either immunocompetent or immunocompromised hosts and selected for increased virulence. C. albicans evolved in immunocompetent hosts rapidly increased virulence, but not in immunocompromised hosts. Taken together, this work suggests that host-produced ROS and AMPs induces genotypic plasticity in C. albicans which facilitates rapid evolution.
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27
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Yang F, Lu H, Wu H, Fang T, Berman J, Jiang YY. Aneuploidy Underlies Tolerance and Cross-Tolerance to Drugs in Candida parapsilosis. Microbiol Spectr 2021; 9:e0050821. [PMID: 34612700 PMCID: PMC8510177 DOI: 10.1128/spectrum.00508-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Accepted: 08/31/2021] [Indexed: 11/20/2022] Open
Abstract
Candida species are the most common human fungal pathogens worldwide. Although C. albicans remains the predominant cause of candidiasis, infections caused by non-albicans Candida species, including C. parapsilosis, are increasing. In C. albicans, genome plasticity has been shown to be a prevalent strategy of adaptation to stresses. However, the role of aneuploidy in C. parapsilosis is largely unknown. In this study, we found that six different aneuploid karyotypes conferred adaptation to the endoplasmic reticulum stress inducer tunicamycin (TUN) in C. parapsilosis. Interestingly, a specific aneuploidy including trisomy of chromosome 6 (Chr6x3) also enabled cross-tolerance to aureobasidin A (AbA), a sphingolipid biosynthesis inhibitor. Consistent with this, selection on AbA identified adaptors with three different aneuploid karyotypes, including Chr6x3, which also enabled cross-tolerance to both AbA and TUN. Therefore, as in other Candida species, recurrent aneuploid karyotypes enable the adaptation of C. parapsilosis to specific stresses, and specific aneuploidies enable cross-adaptation to different stresses. IMPORTANCE Candida parapsilosis is an emerging human fungal pathogen, especially prevalent in neonates. Aneuploidy, having uneven numbers of chromosomes, is a well-known mechanism for adapting to stress in Candida albicans, the most common human fungal pathogen. In this study, we exposed C. parapsilosis to two very different drugs and selected for rare cells that grew in one of the drugs. We found that the majority of isolates that grew in the drugs had acquired an extra copy of one of several aneuploid chromosomes and that specific aneuploid chromosomes appeared in several independent cell clones. Importantly, an extra copy of chromosome 6 was detected following selection in either one of the drugs, and this extra chromosome conferred the ability to grow in both drugs, a property called cross-adaptation, or cross-tolerance. Thus, this study highlights the genome plasticity of C. parapsilosis and the ability of an extra copy of a single chromosome to promote cell growth in the presence of more than one drug.
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Affiliation(s)
- Feng Yang
- Department of Pharmacy, Shanghai Tenth People’s Hospital, School of Medicine, Tongji University, Shanghai, China
- Shmunis School of Biomedical and Cancer Research, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Hui Lu
- Department of Pharmacy, Shanghai Tenth People’s Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Hao Wu
- Department of Pharmacy, Shanghai Tenth People’s Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Ting Fang
- Department of Pharmacy, Shanghai Tenth People’s Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Judith Berman
- Shmunis School of Biomedical and Cancer Research, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Yuan-ying Jiang
- Department of Pharmacy, Shanghai Tenth People’s Hospital, School of Medicine, Tongji University, Shanghai, China
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28
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Adaptation to Fluconazole via Aneuploidy Enables Cross-Adaptation to Amphotericin B and Flucytosine in Cryptococcus neoformans. Microbiol Spectr 2021; 9:e0072321. [PMID: 34585947 PMCID: PMC8557924 DOI: 10.1128/spectrum.00723-21] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The high morbidity and mortality of cryptococcal meningitis is due to the limited range of therapeutic options: only three classes of antifungal drugs are available (polyenes [amphotericin B], azoles [fluconazole], and pyrimidine analogues [flucytosine]). Fluconazole is the most widely used antifungal drug in sub-Saharan Africa, where cryptococcal meningitis is a major cause of death in patients infected with HIV. In this study, we found that exposure to fluconazole, even for short times (48 h) at subinhibitory concentrations, drove rapid adaptation of Cryptococcus neoformans serotype A strain H99 via the acquisition of different aneuploid chromosomes. These aneuploidies conferred heteroresistance to fluconazole. Importantly, most of the adaptors were cross-tolerant to flucytosine. Some of the aneuploid adaptors were not heteroresistant to fluconazole but were tolerant to amphotericin B. Thus, exposure to one antifungal drug class can promote adaptation to two antifungal drug classes, highlighting the plasticity of the C. neoformans genome and raising concerns about the rapid reduction in the range of treatment options for cryptococcal infections. IMPORTANCE Cryptococcosis is a globally distributed invasive fungal infection caused by infections with Cryptococcus neoformans or Cryptococcus gattii. Only three classes of therapeutic drugs are clinically available for treating cryptococcosis: polyenes (amphotericin B), azoles (fluconazole), and pyrimidine analogues (flucytosine). Fluconazole is the primary drug available in resource-limited countries. Aneuploidy is a genomic state due to the gain or loss of chromosomes. We found that C. neoformans rapidly adapted to fluconazole by acquiring diverse aneuploidies and that specific aneuploidies enabled improved growth of isolates susceptible (tolerance) to amphotericin B and/or cross-tolerance to both fluconazole and flucytosine. Therefore, aneuploidy is an underlying mechanism of drug tolerance that not only arises rapidly during growth in fluconazole but can also confer tolerance to other antifungal drugs without prior exposure to those drugs. Resistant isolates have high MICs, and all cells grow similarly in medium with the drug, while tolerant isolates test as susceptible and grow slowly at drug concentrations above the MIC.
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29
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MacAlpine J, Daniel-Ivad M, Liu Z, Yano J, Revie NM, Todd RT, Stogios PJ, Sanchez H, O'Meara TR, Tompkins TA, Savchenko A, Selmecki A, Veri AO, Andes DR, Fidel PL, Robbins N, Nodwell J, Whitesell L, Cowen LE. A small molecule produced by Lactobacillus species blocks Candida albicans filamentation by inhibiting a DYRK1-family kinase. Nat Commun 2021; 12:6151. [PMID: 34686660 PMCID: PMC8536679 DOI: 10.1038/s41467-021-26390-w] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/01/2021] [Indexed: 11/23/2022] Open
Abstract
The fungus Candida albicans is an opportunistic pathogen that can exploit imbalances in microbiome composition to invade its human host, causing pathologies ranging from vaginal candidiasis to fungal sepsis. Bacteria of the genus Lactobacillus are colonizers of human mucosa and can produce compounds with bioactivity against C. albicans. Here, we show that some Lactobacillus species produce a small molecule under laboratory conditions that blocks the C. albicans yeast-to-filament transition, an important virulence trait. It remains unexplored whether the compound is produced in the context of the human host. Bioassay-guided fractionation of Lactobacillus-conditioned medium linked this activity to 1-acetyl-β-carboline (1-ABC). We use genetic approaches to show that filamentation inhibition by 1-ABC requires Yak1, a DYRK1-family kinase. Additional biochemical characterization of structurally related 1-ethoxycarbonyl-β-carboline confirms that it inhibits Yak1 and blocks C. albicans biofilm formation. Thus, our findings reveal Lactobacillus-produced 1-ABC can prevent the yeast-to-filament transition in C. albicans through inhibition of Yak1.
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Affiliation(s)
- Jessie MacAlpine
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | | | - Zhongle Liu
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Junko Yano
- Center of Excellence in Oral and Craniofacial Biology, Louisiana State University Health Sciences Center School of Dentistry, New Orleans, LA, USA
| | - Nicole M Revie
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Robert T Todd
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Peter J Stogios
- BioZone, Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
- Center for Structural Genomics of Infectious Diseases (CSGID), Chicago, IL, USA
| | - Hiram Sanchez
- Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI, USA
| | - Teresa R O'Meara
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Thomas A Tompkins
- Rosell Institute for Microbiome and Probiotics, 6100 Avenue Royalmount, Montreal, QC, Canada
| | - Alexei Savchenko
- BioZone, Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
- Center for Structural Genomics of Infectious Diseases (CSGID), Chicago, IL, USA
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, AB, Canada
| | - Anna Selmecki
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Amanda O Veri
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - David R Andes
- Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI, USA
| | - Paul L Fidel
- Center of Excellence in Oral and Craniofacial Biology, Louisiana State University Health Sciences Center School of Dentistry, New Orleans, LA, USA
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Justin Nodwell
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Luke Whitesell
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada.
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Abstract
How cells exposed to one stress are later able to better survive other types of stress is not well understood. In eukaryotic organisms, physiological and pathological stresses can disturb endoplasmic reticulum (ER) function, resulting in “ER stress.” Here, we found that exposure to tunicamycin, an inducer of ER stress, resulted in the acquisition of a specific aneuploidy, chromosome 2 trisomy (Chr2x3), in Candida albicans. Importantly, the resulting aneuploidy also conferred cross-tolerance to caspofungin, a first-line echinocandin antifungal, as well as to hydroxyurea, a common chemotherapeutic agent. Exposure to a range of tunicamycin concentrations induced similar ER stress responses. Extra copies of one Chr2 gene, MKK2, affected both tunicamycin and caspofungin tolerance, while at least 3 genes on chromosome 2 (ALG7, RTA2, and RTA3) affected only tunicamycin and not caspofungin responses. Other Chr2 genes (RNR1 and RNR21) affected hydroxyurea tolerance but neither tunicamycin nor caspofungin tolerance. Deletion of components of the protein kinase C (PKC) or calcineurin pathways affected tolerance to both tunicamycin and caspofungin, supporting the idea that the ER stress response and echinocandin tolerance are regulated by overlapping stress response pathways. Thus, antifungal drug tolerance can arise rapidly via ER stress-induced aneuploidy.
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Min K, Jannace TF, Si H, Veeramah KR, Haley JD, Konopka JB. Integrative multi-omics profiling reveals cAMP-independent mechanisms regulating hyphal morphogenesis in Candida albicans. PLoS Pathog 2021; 17:e1009861. [PMID: 34398936 PMCID: PMC8389844 DOI: 10.1371/journal.ppat.1009861] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 08/26/2021] [Accepted: 08/02/2021] [Indexed: 12/24/2022] Open
Abstract
Microbial pathogens grow in a wide range of different morphologies that provide distinct advantages for virulence. In the fungal pathogen Candida albicans, adenylyl cyclase (Cyr1) is thought to be a master regulator of the switch to invasive hyphal morphogenesis and biofilm formation. However, faster growing cyr1Δ/Δ pseudorevertant (PR) mutants were identified that form hyphae in the absence of cAMP. Isolation of additional PR mutants revealed that their improved growth was due to loss of one copy of BCY1, the negative regulatory subunit of protein kinase A (PKA) from the left arm of chromosome 2. Furthermore, hyphal morphogenesis was improved in some of PR mutants by multigenic haploinsufficiency resulting from loss of large regions of the left arm of chromosome 2, including global transcriptional regulators. Interestingly, hyphal-associated genes were also induced in a manner that was independent of cAMP. This indicates that basal protein kinase A activity is an important prerequisite to induce hyphae, but activation of adenylyl cyclase is not needed. Instead, phosphoproteomic analysis indicated that the Cdc28 cyclin-dependent kinase and the casein kinase 1 family member Yck2 play key roles in promoting polarized growth. In addition, integrating transcriptomic and proteomic data reveals hyphal stimuli induce increased production of key transcription factors that contribute to polarized morphogenesis.
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Affiliation(s)
- Kyunghun Min
- Department of Microbiology and Immunology, Renaissance School of Medicine, Stony Brook University (SUNY), Stony Brook, New York, United States of America
| | - Thomas F. Jannace
- Department of Microbiology and Immunology, Renaissance School of Medicine, Stony Brook University (SUNY), Stony Brook, New York, United States of America
| | - Haoyu Si
- Department of Microbiology and Immunology, Renaissance School of Medicine, Stony Brook University (SUNY), Stony Brook, New York, United States of America
| | - Krishna R. Veeramah
- Department of Ecology and Evolution, Stony Brook University (SUNY), Stony Brook, New York, United States of America
| | - John D. Haley
- Department of Pathology, Renaissance School of Medicine, Stony Brook University (SUNY), Stony Brook, New York, United States of America
- Biological Mass Spectrometry Shared Resource, Renaissance School of Medicine, Stony Brook University (SUNY), Stony Brook, New York, United States of America
| | - James B. Konopka
- Department of Microbiology and Immunology, Renaissance School of Medicine, Stony Brook University (SUNY), Stony Brook, New York, United States of America
- * E-mail:
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32
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Feistel DJ, Elmostafa R, Hickman MA. Virulence phenotypes result from interactions between pathogen ploidy and genetic background. Ecol Evol 2020; 10:9326-9338. [PMID: 32953064 PMCID: PMC7487253 DOI: 10.1002/ece3.6619] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 07/02/2020] [Accepted: 07/06/2020] [Indexed: 12/25/2022] Open
Abstract
Studying fungal virulence is often challenging and frequently depends on many contexts, including host immune status and pathogen genetic background. However, the role of ploidy has often been overlooked when studying virulence in eukaryotic pathogens. Since fungal pathogens, including the human opportunistic pathogen Candida albicans, can display extensive ploidy variation, assessing how ploidy impacts virulence has important clinical relevance. As an opportunistic pathogen, C. albicans causes nonlethal, superficial infections in healthy individuals, but life-threatening bloodstream infections in individuals with compromised immune function. Here, we determined how both ploidy and genetic background of C. albicans impacts virulence phenotypes in healthy and immunocompromised nematode hosts by characterizing virulence phenotypes in four near-isogenic diploid and tetraploid pairs of strains, which included both laboratory and clinical genetic backgrounds. We found that C. albicans infections decreased host survival and negatively impacted host reproduction, and we leveraged these two measures to survey both lethal and nonlethal virulence phenotypes across the multiple C. albicans strains. In this study, we found that regardless of pathogen ploidy or genetic background, immunocompromised hosts were susceptible to fungal infection compared to healthy hosts. Furthermore, for each host context, we found a significant interaction between C. albicans genetic background and ploidy on virulence phenotypes, but no global differences between diploid and tetraploid pathogens were observed.
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Antifungal Susceptibility of Clinical Yeast Isolates from a Large Canadian Reference Laboratory and Application of Whole-Genome Sequence Analysis To Elucidate Mechanisms of Acquired Resistance. Antimicrob Agents Chemother 2020; 64:AAC.00402-20. [PMID: 32571812 DOI: 10.1128/aac.00402-20] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 06/14/2020] [Indexed: 12/30/2022] Open
Abstract
To understand the epidemiology and susceptibility patterns of yeast infections in Ontario, Canada, we examined 4,715 clinical yeast isolates submitted to our laboratory for antifungal susceptibility testing from 2014 to 2018. Candida albicans was the most frequently submitted species (43.0%), followed by C. glabrata (21.1%), C. parapsilosis (15.0%), and C. tropicalis (6.2%). Twenty-three other Candida spp. (11.6%) and 4 non-Candida species (3.1%) were also identified. Few changes in species distribution were observed from 2014 to 2018, but the total numbers of yeast isolates sent for testing increased, with an annual 7.4% change. According to CLSI clinical breakpoints, resistance rates remained low overall. Moderate fluconazole resistance was noted among C. glabrata (9%), C. parapsilosis (9%), and C. tropicalis (12%) isolates. Only 1% of C. glabrata isolates were resistant to caspofungin, micafungin, and anidulafungin. Whole-genome sequence analysis confirmed 11 cases of acquired resistance to azoles or echinocandins via in-host evolution. There were mutations in the gene for the catalytic subunit of 1,3-beta-glucan synthase-mediated echinocandin resistance in 3 of 3 C. albicans strains, 3 of 4 C. glabrata strains, and 1 strain of C. tropicalis Azole resistance was likely caused by a homozygous ERG3 mutation in 1 C. albicans strain and a previously undescribed chromosomal-duplication event involving ERG11 and TAC1 orthologs in 1 C. tropicalis strain. While antifungal resistance rates remain low among yeast isolates in Ontario, ongoing surveillance is necessary to inform empirical therapy for optimal patient management and to guide antifungal stewardship.
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Todd RT, Selmecki A. Expandable and reversible copy number amplification drives rapid adaptation to antifungal drugs. eLife 2020; 9:e58349. [PMID: 32687060 PMCID: PMC7371428 DOI: 10.7554/elife.58349] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 07/09/2020] [Indexed: 12/13/2022] Open
Abstract
Previously, we identified long repeat sequences that are frequently associated with genome rearrangements, including copy number variation (CNV), in many diverse isolates of the human fungal pathogen Candida albicans (Todd et al., 2019). Here, we describe the rapid acquisition of novel, high copy number CNVs during adaptation to azole antifungal drugs. Single-cell karyotype analysis indicates that these CNVs appear to arise via a dicentric chromosome intermediate and breakage-fusion-bridge cycles that are repaired using multiple distinct long inverted repeat sequences. Subsequent removal of the antifungal drug can lead to a dramatic loss of the CNV and reversion to the progenitor genotype and drug susceptibility phenotype. These findings support a novel mechanism for the rapid acquisition of antifungal drug resistance and provide genomic evidence for the heterogeneity frequently observed in clinical settings.
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Affiliation(s)
- Robert T Todd
- Department of Microbiology and Immunology, University of Minnesota Medical SchoolMinneapolis, MinnesotaUnited States
| | - Anna Selmecki
- Department of Microbiology and Immunology, University of Minnesota Medical SchoolMinneapolis, MinnesotaUnited States
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35
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Tsai CH, Wu AC, Chiang BL, Yang YH, Hung SP, Su MW, Chang YJ, Lee YL. CEACAM3 decreases asthma exacerbations and modulates respiratory syncytial virus latent infection in children. Thorax 2020; 75:725-734. [PMID: 32606071 DOI: 10.1136/thoraxjnl-2019-214132] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 04/15/2020] [Accepted: 05/05/2020] [Indexed: 11/03/2022]
Abstract
BACKGROUND Respiratory syncytial virus (RSV) is associated with childhood asthma. Nevertheless, not all children exposed to RSV develop asthma symptoms, possibly because genes modulate the effects of RSV on asthma exacerbations. OBJECTIVE The purpose of this study was to identify genes that modulate the effect of RSV latent infection on asthma exacerbations. METHODS We performed a meta-analysis to investigate differentially expressed genes (DEGs) of RSV infection from Gene Expression Omnibus datasets. Expression quantitative trait loci (eQTL) methods were applied to select single nucleotide polymorphisms (SNPs) that were associated with DEGs. Gene-based analysis was used to identify SNPs that were significantly associated with asthma exacerbations in the Taiwanese Consortium of Childhood Asthma Study (TCCAS), and validation was attempted in an independent cohort, the Childhood Asthma Management Program (CAMP). Gene-RSV interaction analyses were performed to investigate the association between the interaction of SNPs and RSV latent infection on asthma exacerbations. RESULTS A total of 352 significant DEGs were found by meta-analysis of RSV-related genes. We used 38 123 SNPs related to DEGs to investigate the genetic main effects on asthma exacerbations. We found that eight RSV-related genes (GADD45A, GYPB, MS4A3, NFE2, RNASE3, EPB41L3, CEACAM6 and CEACAM3) were significantly associated with asthma exacerbations in TCCAS and also validated in CAMP. In TCCAS, rs7251960 (CEACAM3) significantly modulated the effect of RSV latent infection on asthma exacerbations (false-discovery rate <0.05). The rs7251960 variant was associated with CEACAM3 mRNA expression in lung tissue (p for trend=1.2×10-7). CEACAM3 mRNA was reduced in nasal mucosa from subjects with asthma exacerbations in two independent datasets. CONCLUSIONS rs7251960 is an eQTL for CEACAM3, and CEACAM3 mRNA expression is reduced in subjects experiencing asthma exacerbations. CEACAM3 may be a modulator of RSV latent infection on asthma exacerbations.
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Affiliation(s)
- Ching-Hui Tsai
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.,Institute of Epidemiology and Preventive Medicine, National Taiwan University, Taipei, Taiwan
| | - Ann Chen Wu
- Center for Healthcare Research in Pediatrics (CHeRP), PRecisiOn Medicine Translational Research (PROMoTeR) Center, Department of Population Medicine, Harvard Pilgrim Health Care Institute and Harvard Medical School, Boston, Massachusetts, USA
| | - Bor-Luen Chiang
- Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan
| | - Yao-Hsu Yang
- Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan
| | - Shih-Pin Hung
- Department of Pediatrics, Cathay General Hospital, Taipei, Taiwan
| | - Ming-Wei Su
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Ya-Jen Chang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Yungling L Lee
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
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Host-Induced Genome Instability Rapidly Generates Phenotypic Variation across Candida albicans Strains and Ploidy States. mSphere 2020; 5:5/3/e00433-20. [PMID: 32493724 PMCID: PMC7273350 DOI: 10.1128/msphere.00433-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Candida albicans is an opportunistic fungal pathogen of humans. The ability to generate genetic variation is essential for adaptation and is a strategy that C. albicans and other fungal pathogens use to change their genome size. Stressful environments, including the host, induce C. albicans genome instability. Here, we investigated how C. albicans genetic background and ploidy state impact genome instability, both in vitro and in a host environment. We show that the host environment induces genome instability, but the magnitude depends on C. albicans genetic background. Furthermore, we show that tetraploid C. albicans is highly unstable in host environments and rapidly reduces in genome size. These reductions in genome size often resulted in reduced virulence. In contrast, diploid C. albicans displayed modest host-induced genome size changes, yet these frequently resulted in increased virulence. Such studies are essential for understanding how opportunistic pathogens respond and potentially adapt to the host environment. Candida albicans is an opportunistic fungal pathogen of humans that is typically diploid yet has a highly labile genome tolerant of large-scale perturbations including chromosomal aneuploidy and loss-of-heterozygosity events. The ability to rapidly generate genetic variation is crucial for C. albicans to adapt to changing or stressful environments, like those encountered in the host. Genetic variation occurs via stress-induced mutagenesis or can be generated through its parasexual cycle, in which tetraploids arise via diploid mating or stress-induced mitotic defects and undergo nonmeiotic ploidy reduction. However, it remains largely unknown how genetic background contributes to C. albicans genome instability in vitro or in the host environment. Here, we tested how genetic background, ploidy, and the host environment impacts C. albicans genome stability. We found that host association induced both loss-of-heterozygosity events and genome size changes, regardless of genetic background or ploidy. However, the magnitude and types of genome changes varied across C. albicans strain background and ploidy state. We then assessed if host-induced genomic changes resulted in fitness consequences on growth rate and nonlethal virulence phenotypes and found that many host-derived isolates significantly changed relative to their parental strain. Interestingly, diploid host-associated C. albicans predominantly decreased host reproductive fitness, whereas tetraploid host-associated C. albicans increased host reproductive fitness. Together, these results are important for understanding how host-induced genomic changes in C. albicans alter its relationship with the host. IMPORTANCECandida albicans is an opportunistic fungal pathogen of humans. The ability to generate genetic variation is essential for adaptation and is a strategy that C. albicans and other fungal pathogens use to change their genome size. Stressful environments, including the host, induce C. albicans genome instability. Here, we investigated how C. albicans genetic background and ploidy state impact genome instability, both in vitro and in a host environment. We show that the host environment induces genome instability, but the magnitude depends on C. albicans genetic background. Furthermore, we show that tetraploid C. albicans is highly unstable in host environments and rapidly reduces in genome size. These reductions in genome size often resulted in reduced virulence. In contrast, diploid C. albicans displayed modest host-induced genome size changes, yet these frequently resulted in increased virulence. Such studies are essential for understanding how opportunistic pathogens respond and potentially adapt to the host environment.
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Enhanced Efflux Pump Expression in Candida Mutants Results in Decreased Manogepix Susceptibility. Antimicrob Agents Chemother 2020; 64:AAC.00261-20. [PMID: 32179530 PMCID: PMC7179633 DOI: 10.1128/aac.00261-20] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 03/04/2020] [Indexed: 12/13/2022] Open
Abstract
Manogepix is a broad-spectrum antifungal agent that inhibits glycosylphosphatidylinositol (GPI) anchor biosynthesis. Using whole-genome sequencing, we characterized two efflux-mediated mechanisms in the fungal pathogens Candida albicans and Candida parapsilosis that resulted in decreased manogepix susceptibility. In C. albicans, a gain-of-function mutation in the transcription factor gene ZCF29 activated expression of ATP-binding cassette transporter genes CDR11 and SNQ2. Manogepix is a broad-spectrum antifungal agent that inhibits glycosylphosphatidylinositol (GPI) anchor biosynthesis. Using whole-genome sequencing, we characterized two efflux-mediated mechanisms in the fungal pathogens Candida albicans and Candida parapsilosis that resulted in decreased manogepix susceptibility. In C. albicans, a gain-of-function mutation in the transcription factor gene ZCF29 activated expression of ATP-binding cassette transporter genes CDR11 and SNQ2. In C. parapsilosis, a mitochondrial deletion activated expression of the major facilitator superfamily transporter gene MDR1.
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38
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Yang F, Teoh F, Tan ASM, Cao Y, Pavelka N, Berman J. Aneuploidy Enables Cross-Adaptation to Unrelated Drugs. Mol Biol Evol 2020; 36:1768-1782. [PMID: 31028698 PMCID: PMC6657732 DOI: 10.1093/molbev/msz104] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Aneuploidy is common both in tumor cells responding to chemotherapeutic agents and in fungal cells adapting to antifungal drugs. Because aneuploidy simultaneously affects many genes, it has the potential to confer multiple phenotypes to the same cells. Here, we analyzed the mechanisms by which Candida albicans, the most prevalent human fungal pathogen, acquires the ability to survive both chemotherapeutic agents and antifungal drugs. Strikingly, adaptation to both types of drugs was accompanied by the acquisition of specific whole-chromosome aneuploidies, with some aneuploid karyotypes recovered independently and repeatedly from very different drug conditions. Specifically, strains selected for survival in hydroxyurea, an anticancer drug, acquired cross-adaptation to caspofungin, a first-line antifungal drug, and both acquired traits were attributable to trisomy of the same chromosome: loss of trisomy was accompanied by loss of adaptation to both drugs. Mechanistically, aneuploidy simultaneously altered the copy number of most genes on chromosome 2, yet survival in hydroxyurea or caspofungin required different genes and stress response pathways. Similarly, chromosome 5 monosomy conferred increased tolerance to both fluconazole and to caspofungin, antifungals with different mechanisms of action. Thus, the potential for cross-adaptation is not a feature of aneuploidy per se; rather, it is dependent on specific genes harbored on given aneuploid chromosomes. Furthermore, pre-exposure to hydroxyurea increased the frequency of appearance of caspofungin survivors, and hydroxyurea-adapted C. albicans cells were refractory to antifungal drug treatment in a mouse model of systemic candidiasis. This highlights the potential clinical consequences for the management of cancer chemotherapy patients at risk of fungal infections.
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Affiliation(s)
- Feng Yang
- Department of Molecular Microbiology and Biotechnology, School of Molecular Cell Biology and Biotechnology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Flora Teoh
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Singapore
| | - Alrina Shin Min Tan
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Singapore
| | - Yongbing Cao
- Department of Vascular Disease, Shanghai TCM-Integrated Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China.,Shanghai TCM-Integrated Institute of Vascular Disease, Shanghai, China
| | - Norman Pavelka
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Singapore
| | - Judith Berman
- Department of Molecular Microbiology and Biotechnology, School of Molecular Cell Biology and Biotechnology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
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The Magnitude of Candida albicans Stress-Induced Genome Instability Results from an Interaction Between Ploidy and Antifungal Drugs. G3-GENES GENOMES GENETICS 2019; 9:4019-4027. [PMID: 31585926 PMCID: PMC6893200 DOI: 10.1534/g3.119.400752] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Organismal ploidy and environmental stress impact the rates and types of mutational events. The opportunistic fungal pathogen Candida albicans, serves as a clinically relevant model for studying the interaction between eukaryotic ploidy and drug-induced mutagenesis. In this study, we compared the rates and types of genome perturbations in diploid and tetraploid C. albicans following exposure to two different classes of antifungal drugs; azoles and echinocandins. We measured mutations at three different scales: point mutation, loss-of-heterozygosity (LOH), and total DNA content for cells exposed to fluconazole and caspofungin. We found that caspofungin induced higher mutation rates than fluconazole, although this is likely an indirect consequence of stress-associated cell wall perturbations, rather than an inherent genotoxicity. Surprisingly, we found that antifungal drugs disproportionately elevated genome and ploidy instability in tetraploid C. albicans compared to diploids. Taken together, our results suggest that the magnitude of stress-induced mutagenesis results from an interaction between ploidy and antifungal drugs. These findings have both clinical and evolutionary implications for how fungal pathogens generate mutations in response to antifungal drug stress and how these mutations may facilitate the emergence of drug resistance.
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40
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A 'parameiosis' drives depolyploidization and homologous recombination in Candida albicans. Nat Commun 2019; 10:4388. [PMID: 31558727 PMCID: PMC6763455 DOI: 10.1038/s41467-019-12376-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 08/28/2019] [Indexed: 12/14/2022] Open
Abstract
Meiosis is a conserved tenet of sexual reproduction in eukaryotes, yet this program is seemingly absent from many extant species. In the human fungal pathogen Candida albicans, mating of diploid cells generates tetraploid products that return to the diploid state via a non-meiotic process of depolyploidization known as concerted chromosome loss (CCL). Here, we report that recombination rates are more than three orders of magnitude higher during CCL than during normal mitotic growth. Furthermore, two conserved ‘meiosis-specific’ factors play central roles in CCL as SPO11 mediates DNA double-strand break formation while both SPO11 and REC8 regulate chromosome stability and promote inter-homolog recombination. Unexpectedly, SPO11 also promotes DNA repair and recombination during normal mitotic divisions. These results indicate that C. albicans CCL represents a ‘parameiosis’ that blurs the conventional boundaries between mitosis and meiosis. They also reveal parallels with depolyploidization in mammalian cells and provide potential insights into the evolution of meiosis. Mating of Candida albicans produces tetraploid products that return to the diploid state via a non-meiotic process known as concerted chromosome loss (CCL). Here, Anderson et al. show high recombination rates during CCL and identify factors that are essential for chromosome stability and recombination during CCL.
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Susceptibility to Medium-Chain Fatty Acids Is Associated with Trisomy of Chromosome 7 in Candida albicans. mSphere 2019; 4:4/3/e00402-19. [PMID: 31243082 PMCID: PMC6595153 DOI: 10.1128/msphere.00402-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Aneuploidy (changes in chromosome number) and loss of heterozygosity (LOH) occur frequently in the human-pathogenic yeast Candida albicans and are associated with adaptation to stress and to antifungal drugs. Aneuploidy and LOH can also be induced during laboratory manipulations, such as during genetic transformation. We find that C. albicans strain SN152, commonly used to generate gene deletions, has undergone a major LOH event on chromosome 2. One deletion strain generated in this background has acquired extra copies of chromosomes 5 and 7. We find that trisomy (three copies) of chromosome 7 is associated with sensitivity to fatty acids. Fatty acids have known antifungal effects and are used in over-the-counter topical treatments. Screening of a collection of gene knockouts in Candida albicans revealed that one strain, carrying a deletion of the transcription factor DAL81, is very susceptible to the medium-chain fatty acid undecanoic acid. However, reintroducing DAL81 does not restore resistance, and editing DAL81 in a different background does not introduce sensitivity. Whole-genome sequencing revealed that the C. albicansdal81Δ/Δ strain has an extra copy of chromosomes 5 and 7. Reversion to resistance to undecanoic acid was induced by growing the sensitive strain in yeast extract-peptone-dextrose with 60 μg/ml undecanoic acid for up to 9 days. Nine isolates that regained some resistance to undecanoic acid lost one copy of chromosome 7. The copy number of chromosome 5 does not appear to affect resistance to fatty acids. Moreover, the sensitivity may be related to having two copies of haplotype B of chromosome 7. In addition, we find that C. albicans strain SN152, used to delete DAL81 and many other genes, has undergone a major loss of heterozygosity event on chromosome 2 and a smaller one on chromosome 3. IMPORTANCE Aneuploidy (changes in chromosome number) and loss of heterozygosity (LOH) occur frequently in the human-pathogenic yeast Candida albicans and are associated with adaptation to stress and to antifungal drugs. Aneuploidy and LOH can also be induced during laboratory manipulations, such as during genetic transformation. We find that C. albicans strain SN152, commonly used to generate gene deletions, has undergone a major LOH event on chromosome 2. One deletion strain generated in this background has acquired extra copies of chromosomes 5 and 7. We find that trisomy (three copies) of chromosome 7 is associated with sensitivity to fatty acids.
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Todd RT, Wikoff TD, Forche A, Selmecki A. Genome plasticity in Candida albicans is driven by long repeat sequences. eLife 2019; 8:45954. [PMID: 31172944 PMCID: PMC6591007 DOI: 10.7554/elife.45954] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Accepted: 06/07/2019] [Indexed: 11/13/2022] Open
Abstract
Genome rearrangements resulting in copy number variation (CNV) and loss of heterozygosity (LOH) are frequently observed during the somatic evolution of cancer and promote rapid adaptation of fungi to novel environments. In the human fungal pathogen Candida albicans, CNV and LOH confer increased virulence and antifungal drug resistance, yet the mechanisms driving these rearrangements are not completely understood. Here, we unveil an extensive array of long repeat sequences (65-6499 bp) that are associated with CNV, LOH, and chromosomal inversions. Many of these long repeat sequences are uncharacterized and encompass one or more coding sequences that are actively transcribed. Repeats associated with genome rearrangements are predominantly inverted and separated by up to ~1.6 Mb, an extraordinary distance for homology-based DNA repair/recombination in yeast. These repeat sequences are a significant source of genome plasticity across diverse strain backgrounds including clinical, environmental, and experimentally evolved isolates, and represent previously uncharacterized variation in the reference genome.
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Affiliation(s)
- Robert T Todd
- Creighton University Medical School, Omaha, United States
| | - Tyler D Wikoff
- Creighton University Medical School, Omaha, United States
| | | | - Anna Selmecki
- Creighton University Medical School, Omaha, United States
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43
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Forche A, Solis NV, Swidergall M, Thomas R, Guyer A, Beach A, Cromie GA, Le GT, Lowell E, Pavelka N, Berman J, Dudley AM, Selmecki A, Filler SG. Selection of Candida albicans trisomy during oropharyngeal infection results in a commensal-like phenotype. PLoS Genet 2019; 15:e1008137. [PMID: 31091232 PMCID: PMC6538192 DOI: 10.1371/journal.pgen.1008137] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 05/28/2019] [Accepted: 04/15/2019] [Indexed: 12/21/2022] Open
Abstract
When the fungus Candida albicans proliferates in the oropharyngeal cavity during experimental oropharyngeal candidiasis (OPC), it undergoes large-scale genome changes at a much higher frequency than when it grows in vitro. Previously, we identified a specific whole chromosome amplification, trisomy of Chr6 (Chr6x3), that was highly overrepresented among strains recovered from the tongues of mice with OPC. To determine the functional significance of this trisomy, we assessed the virulence of two Chr6 trisomic strains and a Chr5 trisomic strain in the mouse model of OPC. We also analyzed the expression of virulence-associated traits in vitro. All three trisomic strains exhibited characteristics of a commensal during OPC in mice. They achieved the same oral fungal burden as the diploid progenitor strain but caused significantly less weight loss and elicited a significantly lower inflammatory host response. In vitro, all three trisomic strains had reduced capacity to adhere to and invade oral epithelial cells and increased susceptibility to neutrophil killing. Whole genome sequencing of pre- and post-infection isolates found that the trisomies were usually maintained. Most post-infection isolates also contained de novo point mutations, but these were not conserved. While in vitro growth assays did not reveal phenotypes specific to de novo point mutations, they did reveal novel phenotypes specific to each lineage. These data reveal that during OPC, clones that are trisomic for Chr5 or Chr6 are selected and they facilitate a commensal-like phenotype. Opportunistic fungal pathogens commonly acquire extra copies of chromosomes that can provide a fitness benefit under acute stress such as exposure to antifungal agents but how these extra copies affect fungal life-style and interactions with their hosts is poorly understood. Here we show that in C. albicans the acquisition of specific whole chromosome trisomies during oropharyngeal infection in mice results in a commensal-like phenotype. Our data indicate that trisomies of chromosomes 5 and 6 alter several related virulence-associated traits that affect how the host recognizes and responds to C. albicans during oropharyngeal infection, thereby inducing this commensal-like phenotype. Whole genome sequencing revealed that trisomies were mostly maintained in subsequent oral infections and that de novo mutations that arose were not shared among strains. We hypothesize that both in vivo and in vitro phenotypes are likely the result of allelic imbalance of specific genes on the trisomic chromosomes, rather than due to whole chromosome trisomy.
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Affiliation(s)
- Anja Forche
- Department of Biology, Bowdoin College, Brunswick, Maine, United States of America
- * E-mail: (AF); (SGF)
| | - Norma V. Solis
- Division of Infectious Diseases, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, California, United States of America
| | - Marc Swidergall
- Division of Infectious Diseases, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, California, United States of America
| | - Robert Thomas
- Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, Nebraska, United States of America
| | - Alison Guyer
- Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, Nebraska, United States of America
| | - Annette Beach
- Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, Nebraska, United States of America
| | - Gareth A. Cromie
- Pacific Northwest Research Institute, Seattle, Washington, United States of America
| | - Giang T. Le
- Singapore Immunology Network (SIgN), Agency of Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Emily Lowell
- Department of Biology, Bowdoin College, Brunswick, Maine, United States of America
| | - Norman Pavelka
- Singapore Immunology Network (SIgN), Agency of Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Judith Berman
- School of Molecular Cell Biology and Biotechnology, Tel Aviv University, Tel Aviv, Israel
| | - Aimeé M. Dudley
- Pacific Northwest Research Institute, Seattle, Washington, United States of America
| | - Anna Selmecki
- Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, Nebraska, United States of America
| | - Scott G. Filler
- Division of Infectious Diseases, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, California, United States of America
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America
- * E-mail: (AF); (SGF)
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Stone NR, Rhodes J, Fisher MC, Mfinanga S, Kivuyo S, Rugemalila J, Segal ES, Needleman L, Molloy SF, Kwon-Chung J, Harrison TS, Hope W, Berman J, Bicanic T. Dynamic ploidy changes drive fluconazole resistance in human cryptococcal meningitis. J Clin Invest 2019; 129:999-1014. [PMID: 30688656 PMCID: PMC6391087 DOI: 10.1172/jci124516] [Citation(s) in RCA: 105] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 11/30/2018] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Cryptococcal meningitis (CM) causes an estimated 180,000 deaths annually, predominantly in sub-Saharan Africa, where most patients receive fluconazole (FLC) monotherapy. While relapse after FLC monotherapy with resistant strains is frequently observed, the mechanisms and impact of emergence of FLC resistance in human CM are poorly understood. Heteroresistance (HetR) - a resistant subpopulation within a susceptible strain - is a recently described phenomenon in Cryptococcus neoformans (Cn) and Cryptococcus gattii (Cg), the significance of which has not previously been studied in humans. METHODS A cohort of 20 patients with HIV-associated CM in Tanzania was prospectively observed during therapy with either FLC monotherapy or in combination with flucytosine (5FC). Total and resistant subpopulations of Cryptococcus spp. were quantified directly from patient cerebrospinal fluid (CSF). Stored isolates underwent whole genome sequencing and phenotypic characterization. RESULTS Heteroresistance was detectable in Cryptococcus spp. in the CSF of all patients at baseline (i.e., prior to initiation of therapy). During FLC monotherapy, the proportion of resistant colonies in the CSF increased during the first 2 weeks of treatment. In contrast, no resistant subpopulation was detectable in CSF by day 14 in those receiving a combination of FLC and 5FC. Genomic analysis revealed high rates of aneuploidy in heteroresistant colonies as well as in relapse isolates, with chromosome 1 (Chr1) disomy predominating. This is apparently due to the presence on Chr1 of ERG11, which is the FLC drug target, and AFR1, which encodes a drug efflux pump. In vitro efflux levels positively correlated with the level of heteroresistance. CONCLUSION Our findings demonstrate for what we believe is the first time the presence and emergence of aneuploidy-driven FLC heteroresistance in human CM, association of efflux levels with heteroresistance, and the successful suppression of heteroresistance with 5FC/FLC combination therapy. FUNDING This work was supported by the Wellcome Trust Strategic Award for Medical Mycology and Fungal Immunology 097377/Z/11/Z and the Daniel Turnberg Travel Fellowship.
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Affiliation(s)
- Neil R.H. Stone
- Centre for Global Health, Institute for Infection and Immunity, St. George’s, University of London, United Kingdom
| | - Johanna Rhodes
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, United Kingdom
| | - Matthew C. Fisher
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, United Kingdom
| | - Sayoki Mfinanga
- National Institute of Medical Research, Dar es Salaam, Tanzania
- Liverpool School of Tropical Medicine, United Kingdom
| | - Sokoine Kivuyo
- National Institute of Medical Research, Dar es Salaam, Tanzania
| | | | - Ella Shtifman Segal
- School of Molecular Cell Biology and Biotechnology, Tel Aviv University, Israel
| | - Leor Needleman
- School of Molecular Cell Biology and Biotechnology, Tel Aviv University, Israel
| | - Síle F. Molloy
- Centre for Global Health, Institute for Infection and Immunity, St. George’s, University of London, United Kingdom
| | | | - Thomas S. Harrison
- Centre for Global Health, Institute for Infection and Immunity, St. George’s, University of London, United Kingdom
| | - William Hope
- Institute of Translational Medicine, University of Liverpool, United Kingdom
| | - Judith Berman
- School of Molecular Cell Biology and Biotechnology, Tel Aviv University, Israel
| | - Tihana Bicanic
- Centre for Global Health, Institute for Infection and Immunity, St. George’s, University of London, United Kingdom
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Sitterlé E, Maufrais C, Sertour N, Palayret M, d'Enfert C, Bougnoux ME. Within-Host Genomic Diversity of Candida albicans in Healthy Carriers. Sci Rep 2019; 9:2563. [PMID: 30796326 PMCID: PMC6385308 DOI: 10.1038/s41598-019-38768-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 01/09/2019] [Indexed: 12/14/2022] Open
Abstract
Genomic variations in Candida albicans, a major fungal pathogen of humans, have been observed upon exposure of this yeast to different stresses and experimental infections, possibly contributing to subsequent adaptation to these stress conditions. Yet, little is known about the extent of genomic diversity that is associated with commensalism, the predominant lifestyle of C. albicans in humans. In this study, we investigated the genetic diversity of C. albicans oral isolates recovered from healthy individuals, using multilocus sequencing typing (MLST) and whole genome sequencing. While MLST revealed occasional differences between isolates collected from a single individual, genome sequencing showed that they differed by numerous single nucleotide polymorphisms, mostly resulting from short-range loss-of-heterozygosity events. These differences were shown to have occurred upon human carriage of C. albicans rather than subsequent in vitro manipulation of the isolates. Thus, C. albicans intra-sample diversity appears common in healthy individuals, higher than that observed using MLST. We propose that diversifying lineages coexist in a single human individual, and this diversity can enable rapid adaptation under stress exposure. These results are crucial for the interpretation of longitudinal studies evaluating the evolution of the C. albicans genome.
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Affiliation(s)
- Emilie Sitterlé
- Fungal Biology and Pathogenicity Unit, Department of Mycology, Institut Pasteur, INRA, Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, Cellule Pasteur, Paris, France
- Unité de Parasitologie-Mycologie, Service de Microbiologie clinique, Hôpital Necker-Enfants-Malades, Assistance Publique des Hôpitaux de Paris (APHP), Paris, France
| | - Corinne Maufrais
- Center for Bioinformatics, BioStatistics and Integrative Biology (C3BI), USR 3756 IP CNRS, Institut Pasteur, Paris, France
| | - Natacha Sertour
- Fungal Biology and Pathogenicity Unit, Department of Mycology, Institut Pasteur, INRA, Paris, France
| | | | - Christophe d'Enfert
- Fungal Biology and Pathogenicity Unit, Department of Mycology, Institut Pasteur, INRA, Paris, France
| | - Marie-Elisabeth Bougnoux
- Fungal Biology and Pathogenicity Unit, Department of Mycology, Institut Pasteur, INRA, Paris, France.
- Unité de Parasitologie-Mycologie, Service de Microbiologie clinique, Hôpital Necker-Enfants-Malades, Assistance Publique des Hôpitaux de Paris (APHP), Paris, France.
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Identification of Recessive Lethal Alleles in the Diploid Genome of a Candida albicans Laboratory Strain Unveils a Potential Role of Repetitive Sequences in Buffering Their Deleterious Impact. mSphere 2019; 4:4/1/e00709-18. [PMID: 30760617 PMCID: PMC6374597 DOI: 10.1128/msphere.00709-18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The heterozygous diploid genome of Candida albicans is highly plastic, with frequent loss of heterozygosity (LOH) events. In the SC5314 laboratory strain, while LOH events are ubiquitous, a chromosome homozygosis bias is observed for certain chromosomes, whereby only one of the two homologs can occur in the homozygous state. This suggests the occurrence of recessive lethal allele(s) (RLA) preventing large-scale LOH events on these chromosomes from being stably maintained. To verify the presence of an RLA on chromosome 7 (Chr7), we utilized a system that allows (i) DNA double-strand break (DSB) induction on Chr7 by the I-SceI endonuclease and (ii) detection of the resulting long-range homozygosis. I-SceI successfully induced a DNA DSB on both Chr7 homologs, generally repaired by gene conversion. Notably, cells homozygous for the right arm of Chr7B were not recovered, confirming the presence of RLA(s) in this region. Genome data mining for RLA candidates identified a premature nonsense-generating single nucleotide polymorphism (SNP) within the HapB allele of C7_03400c whose Saccharomyces cerevisiae ortholog encodes the essential Mtr4 RNA helicase. Complementation with a wild-type copy of MTR4 rescued cells homozygous for the right arm of Chr7B, demonstrating that the mtr4K880* RLA is responsible for the Chr7 homozygosis bias in strain SC5314. Furthermore, we observed that the major repeat sequences (MRS) on Chr7 acted as hot spots for interhomolog recombination. Such recombination events provide C. albicans with increased opportunities to survive DNA DSBs whose repair can lead to homozygosis of recessive lethal or deleterious alleles. This might explain the maintenance of MRS in this species.IMPORTANCE Candida albicans is a major fungal pathogen, whose mode of reproduction is mainly clonal. Its genome is highly tolerant to rearrangements, in particular loss of heterozygosity events, known to unmask recessive lethal and deleterious alleles in heterozygous diploid organisms such as C. albicans By combining a site-specific DSB-inducing system and mining genome sequencing data of 182 C. albicans isolates, we were able to ascribe the chromosome 7 homozygosis bias of the C. albicans laboratory strain SC5314 to an heterozygous SNP introducing a premature STOP codon in the MTR4 gene. We have also proposed genome-wide candidates for new recessive lethal alleles. We additionally observed that the major repeat sequences (MRS) on chromosome 7 acted as hot spots for interhomolog recombination. Maintaining MRS in C. albicans could favor haplotype exchange, of vital importance to LOH events, leading to homozygosis of recessive lethal or deleterious alleles that inevitably accumulate upon clonality.
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Polvi EJ, Veri AO, Liu Z, Hossain S, Hyde S, Kim SH, Tebbji F, Sellam A, Todd RT, Xie JL, Lin ZY, Wong CJ, Shapiro RS, Whiteway M, Robbins N, Gingras AC, Selmecki A, Cowen LE. Functional divergence of a global regulatory complex governing fungal filamentation. PLoS Genet 2019; 15:e1007901. [PMID: 30615616 PMCID: PMC6336345 DOI: 10.1371/journal.pgen.1007901] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 01/17/2019] [Accepted: 12/16/2018] [Indexed: 01/17/2023] Open
Abstract
Morphogenetic transitions are prevalent in the fungal kingdom. For a leading human fungal pathogen, Candida albicans, the capacity to transition between yeast and filaments is key for virulence. For the model yeast Saccharomyces cerevisiae, filamentation enables nutrient acquisition. A recent functional genomic screen in S. cerevisiae identified Mfg1 as a regulator of morphogenesis that acts in complex with Flo8 and Mss11 to mediate transcriptional responses crucial for filamentation. In C. albicans, Mfg1 also interacts physically with Flo8 and Mss11 and is critical for filamentation in response to diverse cues, but the mechanisms through which it regulates morphogenesis remained elusive. Here, we explored the consequences of perturbation of Mfg1, Flo8, and Mss11 on C. albicans morphogenesis, and identified functional divergence of complex members. We observed that C. albicans Mss11 was dispensable for filamentation, and that overexpression of FLO8 caused constitutive filamentation even in the absence of Mfg1. Harnessing transcriptional profiling and chromatin immunoprecipitation coupled to microarray analysis, we identified divergence between transcriptional targets of Flo8 and Mfg1 in C. albicans. We also established that Flo8 and Mfg1 cooperatively bind to promoters of key regulators of filamentation, including TEC1, for which overexpression was sufficient to restore filamentation in the absence of Flo8 or Mfg1. To further explore the circuitry through which Mfg1 regulates morphogenesis, we employed a novel strategy to select for mutations that restore filamentation in the absence of Mfg1. Whole genome sequencing of filamentation-competent mutants revealed chromosome 6 amplification as a conserved adaptive mechanism. A key determinant of the chromosome 6 amplification is FLO8, as deletion of one allele blocked morphogenesis, and chromosome 6 was not amplified in evolved lineages for which FLO8 was re-located to a different chromosome. Thus, this work highlights rewiring of key morphogenetic regulators over evolutionary time and aneuploidy as an adaptive mechanism driving fungal morphogenesis. Fungal infections pose a severe burden to human health worldwide. Candida albicans is a leading cause of systemic fungal infections, with mortality rates approaching 40%. One of the key virulence traits of this fungus is its ability to transition between yeast and filamentous forms in response to diverse host-relevant cues. The model yeast Saccharomyces cerevisiae is also capable of filamentous growth in certain conditions, and previous work has identified a key transcriptional complex required for filamentation in both species. However, here we discover that the circuitry governed by this complex in C. albicans is largely distinct from that in the non-pathogenic S. cerevisiae. We also employ a novel selection strategy to perform experimental evolution, identifying chromosome triplication as a mechanism to restore filamentation in a non-filamentous mutant. This work reveals unique circuitry governing a key virulence trait in a leading fungal pathogen, identifying potential therapeutic targets to combat these life-threatening infections.
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Affiliation(s)
- Elizabeth J. Polvi
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Amanda O. Veri
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Zhongle Liu
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Saif Hossain
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Sabrina Hyde
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Sang Hu Kim
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Faiza Tebbji
- Infectious Disease Research Centre, Université Laval, Quebec, Canada
| | - Adnane Sellam
- Infectious Disease Research Centre, Université Laval, Quebec, Canada
| | - Robert T. Todd
- Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, Nebraska, United States of America
| | - Jinglin L. Xie
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Zhen-Yuan Lin
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Ontario, Canada
| | - Cassandra J. Wong
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Ontario, Canada
| | - Rebecca S. Shapiro
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | | | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Anne-Claude Gingras
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Ontario, Canada
| | - Anna Selmecki
- Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, Nebraska, United States of America
| | - Leah E. Cowen
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
- * E-mail:
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Antifungal tolerance is a subpopulation effect distinct from resistance and is associated with persistent candidemia. Nat Commun 2018; 9:2470. [PMID: 29941885 PMCID: PMC6018213 DOI: 10.1038/s41467-018-04926-x] [Citation(s) in RCA: 139] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 06/05/2018] [Indexed: 11/23/2022] Open
Abstract
Tolerance to antifungal drug concentrations above the minimal inhibitory concentration (MIC) is rarely quantified, and current clinical recommendations suggest it should be ignored. Here, we quantify antifungal tolerance in Candida albicans isolates as the fraction of growth above the MIC, and find that it is distinct from susceptibility/resistance. Instead, tolerance is due to the slow growth of subpopulations of cells that overcome drug stress more efficiently than the rest of the population, and correlates inversely with intracellular drug accumulation. Many adjuvant drugs used in combination with fluconazole, a widely used fungistatic drug, reduce tolerance without affecting resistance. Accordingly, in an invertebrate infection model, adjuvant combination therapy is more effective than fluconazole in treating infections with highly tolerant isolates and does not affect infections with low tolerance isolates. Furthermore, isolates recovered from immunocompetent patients with persistent candidemia display higher tolerance than isolates readily cleared by fluconazole. Thus, tolerance correlates with, and may help predict, patient responses to fluconazole therapy. The authors show that antifungal tolerance, defined as the fraction of growth of a fungal pathogen above the minimal inhibitory concentration, is due to the slow growth of subpopulations of cells that overcome drug stress, and that high tolerance is often associated with persistent infections.
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Mount HO, Revie NM, Todd RT, Anstett K, Collins C, Costanzo M, Boone C, Robbins N, Selmecki A, Cowen LE. Global analysis of genetic circuitry and adaptive mechanisms enabling resistance to the azole antifungal drugs. PLoS Genet 2018; 14:e1007319. [PMID: 29702647 PMCID: PMC5922528 DOI: 10.1371/journal.pgen.1007319] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 03/19/2018] [Indexed: 12/20/2022] Open
Abstract
Invasive fungal infections caused by the pathogen Candida albicans have transitioned from a rare curiosity to a major cause of human mortality. This is in part due to the emergence of resistance to the limited number of antifungals available to treat fungal infections. Azoles function by targeting the biosynthesis of ergosterol, a key component of the fungal cell membrane. Loss-of-function mutations in the ergosterol biosynthetic gene ERG3 mitigate azole toxicity and enable resistance that depends upon fungal stress responses. Here, we performed a genome-wide synthetic genetic array screen in Saccharomyces cerevisiae to map ERG3 genetic interactors and uncover novel circuitry important for azole resistance. We identified nine genes that enabled erg3-mediated azole resistance in the model yeast and found that only two of these genes had a conserved impact on resistance in C. albicans. Further, we screened a C. albicans homozygous deletion mutant library and identified 13 genes for which deletion enhances azole susceptibility. Two of the genes, RGD1 and PEP8, were also important for azole resistance acquired by diverse mechanisms. We discovered that loss of function of retrograde transport protein Pep8 overwhelms the functional capacity of the stress response regulator calcineurin, thereby abrogating azole resistance. To identify the mechanism through which the GTPase activator protein Rgd1 enables azole resistance, we selected for mutations that restore resistance in strains lacking Rgd1. Whole genome sequencing uncovered parallel adaptive mechanisms involving amplification of both chromosome 7 and a large segment of chromosome 3. Overexpression of a transporter gene on the right portion of chromosome 3, NPR2, was sufficient to enable azole resistance in the absence of Rgd1. Thus, we establish a novel mechanism of adaptation to drug-induced stress, define genetic circuitry underpinning azole resistance, and illustrate divergence in resistance circuitry over evolutionary time. Fungal infections caused by the pathogen Candida albicans pose a serious threat to human health. Treating these infections relies heavily on the azole antifungals, however, resistance to these drugs develops readily demanding novel therapeutic strategies. We performed large-scale systematic screens in both C. albicans and the model yeast Saccharomyces cerevisiae to identify genes that enable azole resistance. Our genome-wide screen in S. cerevisiae identified nine determinants of azole resistance, only two of which were important for resistance in C. albicans. Our screen of C. albicans mutants identified 13 genes for which deletion enhances susceptibility to azoles, including RGD1 and PEP8. We found that loss of Pep8 overwhelms the functional capacity of a key stress response regulator, calcineurin. In contrast, amplification of chromosome 7 and the right portion of chromosome 3 can restore resistance in strains lacking Rgd1, suggesting that Rgd1 may enable azole resistance by inducing genes in these amplified regions. Specifically, overexpression of a gene involved in transport on chromosome 3, NPR2, was sufficient to restore azole resistance in the absence of Rgd1. Thus, we establish novel circuitry important for antifungal drug resistance, and uncover adaptive mechanisms involving genomic plasticity that occur in response to drug induced stress.
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Affiliation(s)
| | - Nicole M. Revie
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Robert T. Todd
- Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, Nebraska, United States of America
| | - Kaitlin Anstett
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Cathy Collins
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Michael Costanzo
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Charles Boone
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Anna Selmecki
- Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, Nebraska, United States of America
| | - Leah E. Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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50
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Abstract
The ability of an organism to replicate and segregate its genome with high fidelity is vital to its survival and for the production of future generations. Errors in either of these steps (replication or segregation) can lead to a change in ploidy or chromosome number. While these drastic genome changes can be detrimental to the organism, resulting in decreased fitness, they can also provide increased fitness during periods of stress. A change in ploidy or chromosome number can fundamentally change how a cell senses and responds to its environment. Here, we discuss current ideas in fungal biology that illuminate how eukaryotic genome size variation can impact the organism at a cellular and evolutionary level. One of the most fascinating observations from the past 2 decades of research is that some fungi have evolved the ability to tolerate large genome size changes and generate vast genomic heterogeneity without undergoing canonical meiosis.
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