1
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Yiu B, Robbins N, Cowen LE. Interdisciplinary approaches for the discovery of novel antifungals. Trends Mol Med 2024; 30:723-735. [PMID: 38777733 DOI: 10.1016/j.molmed.2024.04.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 04/10/2024] [Accepted: 04/26/2024] [Indexed: 05/25/2024]
Abstract
Pathogenic fungi are an increasing public health concern. The emergence of antifungal resistance coupled with the scarce antifungal arsenal highlights the need for novel therapeutics. Fortunately, the past few years have witnessed breakthroughs in antifungal development. Here, we discuss pivotal interdisciplinary approaches for the discovery of novel compounds with efficacy against diverse fungal pathogens. We highlight breakthroughs in improving current antifungal scaffolds, as well as the utility of compound combinations to extend the lifespan of antifungals. Finally, we describe efforts to refine candidate chemical scaffolds by leveraging structure-guided approaches, and the use of functional genomics to expand our knowledge of druggable antifungal targets. Overall, we emphasize the importance of interdisciplinary collaborations in the endeavor to develop innovative antifungal strategies.
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Affiliation(s)
- Bonnie Yiu
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5G 1M1, Canada
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5G 1M1, Canada
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5G 1M1, Canada.
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2
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Gil-Gomez A, Rest JS. Wiring Between Close Nodes in Molecular Networks Evolves More Quickly Than Between Distant Nodes. Mol Biol Evol 2024; 41:msae098. [PMID: 38768245 PMCID: PMC11136681 DOI: 10.1093/molbev/msae098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 04/14/2024] [Accepted: 05/15/2024] [Indexed: 05/22/2024] Open
Abstract
As species diverge, a wide range of evolutionary processes lead to changes in protein-protein interaction (PPI) networks and metabolic networks. The rate at which molecular networks evolve is an important question in evolutionary biology. Previous empirical work has focused on interactomes from model organisms to calculate rewiring rates, but this is limited by the relatively small number of species and sparse nature of network data across species. We present a proxy for variation in network topology: variation in drug-drug interactions (DDIs), obtained by studying drug combinations (DCs) across taxa. Here, we propose the rate at which DDIs change across species as an estimate of the rate at which the underlying molecular network changes as species diverge. We computed the evolutionary rates of DDIs using previously published data from a high-throughput study in gram-negative bacteria. Using phylogenetic comparative methods, we found that DDIs diverge rapidly over short evolutionary time periods, but that divergence saturates over longer time periods. In parallel, we mapped drugs with known targets in PPI and cofunctional networks. We found that the targets of synergistic DDIs are closer in these networks than other types of DCs and that synergistic interactions have a higher evolutionary rate, meaning that nodes that are closer evolve at a faster rate. Future studies of network evolution may use DC data to gain larger-scale perspectives on the details of network evolution within and between species.
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Affiliation(s)
- Alejandro Gil-Gomez
- Department of Ecology and Evolution, Laufer Center for Physical and Quantitative Biology, Stony Brook University, 650 Life Sciences, Stony Brook, NY 11794-4254, USA
| | - Joshua S Rest
- Department of Ecology and Evolution, Laufer Center for Physical and Quantitative Biology, Stony Brook University, 650 Life Sciences, Stony Brook, NY 11794-4254, USA
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3
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Caza M, Santos DA, Burden E, Brisland A, Hu G, Kronstad JW. Proteasome inhibition as a therapeutic target for the fungal pathogen Cryptococcus neoformans. Microbiol Spectr 2023; 11:e0190423. [PMID: 37750732 PMCID: PMC10580939 DOI: 10.1128/spectrum.01904-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 08/07/2023] [Indexed: 09/27/2023] Open
Abstract
The current therapeutic challenges for treating fungal diseases demand new approaches and new drugs. A promising strategy involves combination therapy with agents of distinct mechanisms of action to increase fungicidal activity and limit the impact of mutations leading to resistance. In this study, we evaluated the antifungal potential of bortezomib by examining the inhibition of proteasome activity, cell proliferation, and capsule production by Cryptococcus neoformans, the causative agent of fungal meningoencephalitis. Chemical genetic screens with collections of deletion mutants identified potential druggable targets for combination therapy with bortezomib. In vitro assays of combinations of bortezomib with flucytosine, chlorpromazine, bafilomycin A1, copper sulfate, or hydroxyurea revealed antifungal effects against C. neoformans. Furthermore, combination treatment with bortezomib and flucytosine in a murine inhalation model of cryptococcosis resulted in the improvement of neurological functions and reduced fungal replication and dissemination, leading to a delay in disease progression. This study therefore highlights the utility of chemical genetic screens to identify new therapeutic approaches as well as the antifungal potential of proteasome inhibition. IMPORTANCE Fungal diseases of humans are difficult to treat, and there is a clear need for additional antifungal drugs, better diagnostics, effective vaccines, and new approaches to deal with emerging drug resistance. Fungi are challenging to control because they share many common biochemical functions with their mammalian hosts and it is therefore difficult to identify fungal-specific targets for drug development. One approach is to employ existing antifungal drugs in combination with agents that target common cellular processes at levels that are (ideally) not toxic for the host. We pursued this approach in this study by examining the potential of the clinically approved proteasome inhibitor bortezomib to influence the proliferation and virulence of Cryptococcus neoformans. We found that the combination of bortezomib with the anti-cryptococcal drug flucytosine improved the survival of infected mice, thus demonstrating the potential of this strategy for antifungal therapy.
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Affiliation(s)
- Mélissa Caza
- Department of Microbiology and Immunology, Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - Daniel Assis Santos
- Department of Microbiology, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Elizabeth Burden
- Department of Microbiology and Immunology, Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - Anna Brisland
- Department of Microbiology and Immunology, Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - Guanggan Hu
- Department of Microbiology and Immunology, Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - James W. Kronstad
- Department of Microbiology and Immunology, Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
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4
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Chen L, Zhang L, Xie Y, Wang Y, Tian X, Fang W, Xue X, Wang L. Confronting antifungal resistance, tolerance, and persistence: Advances in drug target discovery and delivery systems. Adv Drug Deliv Rev 2023; 200:115007. [PMID: 37437715 DOI: 10.1016/j.addr.2023.115007] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 07/01/2023] [Accepted: 07/06/2023] [Indexed: 07/14/2023]
Abstract
Human pathogenic fungi pose a serious threat to human health and safety. Unfortunately, the limited number of antifungal options is exacerbated by the continuous emergence of drug-resistant variants, leading to frequent drug treatment failures. Recent studies have also highlighted the clinical importance of other modes of fungal survival of antifungal treatment, including drug tolerance and persistence, pointing to the complexity of the fungal response to antifungal drugs. A lack of understanding of the fungal drug response has hampered the identification of new targets, the development of alternative antifungal strategies and the design of appropriate delivery systems. In this review we summarize recent advances in the study of antifungal resistance, tolerance and persistence, with an emphasis on promising drug targets and drug delivery systems that may yield important insights into the development of new or improved antifungal therapies against fungal infections.
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Affiliation(s)
- Lei Chen
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Lanyue Zhang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Yuyan Xie
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Yiting Wang
- College of Life Sciences, Hebei University, Baoding, Hebei 071002, China
| | - Xiuyun Tian
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Wenxia Fang
- Institute of Biological Science and Technology, Guangxi Academy of Sciences, Nanning, 530007, Guangxi, China
| | - Xinying Xue
- Department of Respiratory and Critical Care, Beijing Shijitan Hospital, Capital Medical University; Peking University Ninth School of Clinical Medicine, Beijing 100038, China; Department of Respiratory and Critical Care, Weifang Medical College, 261053, Weifang, Shandong, China.
| | - Linqi Wang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China.
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5
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Zhu P, Li Y, Guo T, Liu S, Tancer RJ, Hu C, Zhao C, Xue C, Liao G. New antifungal strategies: drug combination and co-delivery. Adv Drug Deliv Rev 2023; 198:114874. [PMID: 37211279 DOI: 10.1016/j.addr.2023.114874] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Revised: 05/12/2023] [Accepted: 05/14/2023] [Indexed: 05/23/2023]
Abstract
The growing occurrence of invasive fungal infections and the mounting rates of drug resistance constitute a significant menace to human health. Antifungal drug combinations have garnered substantial interest for their potential to improve therapeutic efficacy, reduce drug doses, reverse, or ameliorate drug resistance. A thorough understanding of the molecular mechanisms underlying antifungal drug resistance and drug combination is key to developing new drug combinations. Here we discuss the mechanisms of antifungal drug resistance and elucidate how to discover potent drug combinations to surmount resistance. We also examine the challenges encountered in developing such combinations and discuss prospects, including advanced drug delivery strategies.
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Affiliation(s)
- Ping Zhu
- State Key Laboratory of Silkworm Genome Biology, College of Pharmaceutical Sciences, Southwest University, Chongqing, 400700, China
| | - Yan Li
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing 100050, China
| | - Ting Guo
- State Key Laboratory of Silkworm Genome Biology, College of Pharmaceutical Sciences, Southwest University, Chongqing, 400700, China
| | - Simei Liu
- Department of Traditional Chinese Medicine, Chongqing College of Traditional Chinese Medicine, Chongqing 402760, China; Institute of Pharmacology and Toxicology, Chongqing Academy of Chinese Materia Medica, Chongqing 400065, China
| | - Robert J Tancer
- Public Health Research Institute and Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers University, Newark, NJ, 07103, USA
| | - Changhua Hu
- State Key Laboratory of Silkworm Genome Biology, College of Pharmaceutical Sciences, Southwest University, Chongqing, 400700, China
| | - Chengzhi Zhao
- Chongqing Health Center for Women and Children, Chongqing, 400700, PR China.
| | - Chaoyang Xue
- Public Health Research Institute and Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers University, Newark, NJ, 07103, USA
| | - Guojian Liao
- State Key Laboratory of Silkworm Genome Biology, College of Pharmaceutical Sciences, Southwest University, Chongqing, 400700, China.
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6
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Del Poeta M, Wormley FL, Lin X. Host populations, challenges, and commercialization of cryptococcal vaccines. PLoS Pathog 2023; 19:e1011115. [PMID: 36757929 PMCID: PMC9910758 DOI: 10.1371/journal.ppat.1011115] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023] Open
Abstract
Vaccines are one of the most effective public health tools to prevent and manage infectious diseases. Since the first clinical use of vaccines in the late 18th century, many vaccines have been successfully developed to combat bacterial and viral infections, including the most recent Coronavirus Disease 2019 (COVID-19) pandemic. However, there remains no vaccine that is clinically available to treat or prevent invasive fungal diseases, including cryptococcal meningoencephalitis. This fungal disease is uniformly fatal without treatment and has a global mortality rate of over 70%. Despite a dire need for an effective cryptococcal vaccine, there are many scientific and economic challenges to overcome prior to making it a reality. Here, we discuss some of these challenges as well as steps that the community is taking for commercialization of effective cryptococcal vaccines.
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Affiliation(s)
- Maurizio Del Poeta
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, United States of America,Division of Infectious Diseases, Stony Brook University, Stony Brook, New York, United States of America,Institute of Chemical Biology and Drug Discovery, Stony Brook University, Stony Brook, New York, United States of America,Veteran Administration Medical Center, Northport, New York, United States of America,* E-mail: (MDP); (FLW); (XL)
| | - Floyd L. Wormley
- Department of Biology, Texas Christian University, Fort Worth, Texas, United States of America,* E-mail: (MDP); (FLW); (XL)
| | - Xiaorong Lin
- Department of Microbiology, University of Georgia, Athens, Georgia, United States of America,* E-mail: (MDP); (FLW); (XL)
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7
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Poulton NC, Rock JM. Unraveling the mechanisms of intrinsic drug resistance in Mycobacterium tuberculosis. Front Cell Infect Microbiol 2022; 12:997283. [PMID: 36325467 PMCID: PMC9618640 DOI: 10.3389/fcimb.2022.997283] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 09/30/2022] [Indexed: 02/03/2023] Open
Abstract
Tuberculosis (TB) is among the most difficult infections to treat, requiring several months of multidrug therapy to produce a durable cure. The reasons necessitating long treatment times are complex and multifactorial. However, one major difficulty of treating TB is the resistance of the infecting bacterium, Mycobacterium tuberculosis (Mtb), to many distinct classes of antimicrobials. This review will focus on the major gaps in our understanding of intrinsic drug resistance in Mtb and how functional and chemical-genetics can help close those gaps. A better understanding of intrinsic drug resistance will help lay the foundation for strategies to disarm and circumvent these mechanisms to develop more potent antitubercular therapies.
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8
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Robbins N, Cowen LE. Antifungal discovery. Curr Opin Microbiol 2022; 69:102198. [PMID: 36037637 PMCID: PMC10726697 DOI: 10.1016/j.mib.2022.102198] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 07/29/2022] [Accepted: 08/02/2022] [Indexed: 11/30/2022]
Abstract
Fungi have a profound impact on human health, leading to billions of infections and millions of deaths worldwide each year. Exacerbating the public health burden is the continued emergence of drug-resistant fungal pathogens coupled with a dearth of treatment options to combat serious infections. Despite this health threat, scientific advances in chemistry, genetics, and biochemistry methodologies have enabled novel antifungal compounds to be discovered. Here, we describe current approaches for the discovery and characterization of novel antifungals, focusing on the identification of novel chemical matter and elucidation of the cellular target of bioactive compounds, followed by a review of the most promising emerging therapies in the antifungal-development pipeline.
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Affiliation(s)
- Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada.
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9
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Robbins N, Cowen LE. Genomic Approaches to Antifungal Drug Target Identification and Validation. Annu Rev Microbiol 2022; 76:369-388. [PMID: 35650665 PMCID: PMC10727914 DOI: 10.1146/annurev-micro-041020-094524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The last several decades have witnessed a surge in drug-resistant fungal infections that pose a serious threat to human health. While there is a limited arsenal of drugs that can be used to treat systemic infections, scientific advances have provided renewed optimism for the discovery of novel antifungals. The development of chemical-genomic assays using Saccharomyces cerevisiae has provided powerful methods to identify the mechanism of action of molecules in a living cell. Advances in molecular biology techniques have enabled complementary assays to be developed in fungal pathogens, including Candida albicans and Cryptococcus neoformans. These approaches enable the identification of target genes for drug candidates, as well as genes involved in buffering drug target pathways. Here, we examine yeast chemical-genomic assays and highlight how such resources can be utilized to predict the mechanisms of action of compounds, to study virulence attributes of diverse fungal pathogens, and to bolster the antifungal pipeline.
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Affiliation(s)
- Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada;
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada;
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10
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Dang EV, Lei S, Radkov A, Volk RF, Zaro BW, Madhani HD. Secreted fungal virulence effector triggers allergic inflammation via TLR4. Nature 2022; 608:161-167. [PMID: 35896747 PMCID: PMC9744105 DOI: 10.1038/s41586-022-05005-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 06/21/2022] [Indexed: 12/14/2022]
Abstract
Invasive fungal pathogens are major causes of human mortality and morbidity1,2. Although numerous secreted effector proteins that reprogram innate immunity to promote virulence have been identified in pathogenic bacteria, so far, there are no examples of analogous secreted effector proteins produced by human fungal pathogens. Cryptococcus neoformans, the most common cause of fungal meningitis and a major pathogen in AIDS, induces a pathogenic type 2 response characterized by pulmonary eosinophilia and alternatively activated macrophages3-8. Here, we identify CPL1 as an effector protein secreted by C. neoformans that drives alternative activation (also known as M2 polarization) of macrophages to enable pulmonary infection in mice. We observed that CPL1-enhanced macrophage polarization requires Toll-like receptor 4, which is best known as a receptor for bacterial endotoxin but is also a poorly understood mediator of allergen-induced type 2 responses9-12. We show that this effect is caused by CPL1 itself and not by contaminating lipopolysaccharide. CPL1 is essential for virulence, drives polarization of interstitial macrophages in vivo, and requires type 2 cytokine signalling for its effect on infectivity. Notably, C. neoformans associates selectively with polarized interstitial macrophages during infection, suggesting a mechanism by which C. neoformans generates its own intracellular replication niche within the host. This work identifies a circuit whereby a secreted effector protein produced by a human fungal pathogen reprograms innate immunity, revealing an unexpected role for Toll-like receptor 4 in promoting the pathogenesis of infectious disease.
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Affiliation(s)
- Eric V. Dang
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA, United States of America
| | - Susan Lei
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA, United States of America
| | - Atanas Radkov
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA, United States of America
| | - Regan F. Volk
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA, United States of America,Cardiovascular Research Institute, University of California, San Francisco, CA, United States of America
| | - Balyn W. Zaro
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA, United States of America,Cardiovascular Research Institute, University of California, San Francisco, CA, United States of America
| | - Hiten D. Madhani
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA, United States of America,Chan-Zuckerberg Biohub, San Francisco, CA, United States of America,
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11
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Breuer MR, Dasgupta A, Vasselli JG, Lin X, Shaw BD, Sachs MS. The Antidepressant Sertraline Induces the Formation of Supersized Lipid Droplets in the Human Pathogen Cryptococcus neoformans. J Fungi (Basel) 2022; 8:jof8060642. [PMID: 35736125 PMCID: PMC9224953 DOI: 10.3390/jof8060642] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/13/2022] [Accepted: 06/15/2022] [Indexed: 01/11/2023] Open
Abstract
The prevalence and increasing incidence of fungal infections globally is a significant worldwide health problem. Cryptococcosis, primarily caused by the pathogenic yeast Cryptococcus neoformans, is responsible for approximately 181,000 estimated deaths annually. The scarcity of treatments and the increasing resistance to current therapeutics highlight the need for the development of antifungal agents which have novel mechanisms of action and are suitable for clinical use. Repurposing existing FDA-approved compounds as antimycotic therapeutics is a promising strategy for the rapid development of such new treatments. Sertraline (SRT), a commonly prescribed antidepressant, is a broad-spectrum antifungal agent with particular efficacy against C. neoformans. However, the effect of SRT on fungal physiology is not understood. Here, we report that SRT induces the formation of supersized lipid droplets (SLDs) in C. neoformans, and in Candida albicans, Saccharomyces cerevisiae, and Aspergillus fumigatus. SLDs were not induced in C. neoformans by treatment with the antifungal fluconazole (FLC), consistent with SRT and FLC acting differently to perturb C. neoformans physiology. The formation of SLDs in response to SRT indicates that this compound alters the lipid metabolism of C. neoformans. Moreover, the SRT-induced enlargement of LDs in other fungal species may indicate a common fungal response to SRT.
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Affiliation(s)
- Matthew R. Breuer
- Department of Biology, Texas A&M University, College Station, TX 77843, USA; (M.R.B.); (A.D.)
| | - Ananya Dasgupta
- Department of Biology, Texas A&M University, College Station, TX 77843, USA; (M.R.B.); (A.D.)
| | - Joseph G. Vasselli
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, USA; (J.G.V.); (B.D.S.)
| | - Xiaorong Lin
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA;
| | - Brian D. Shaw
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, USA; (J.G.V.); (B.D.S.)
| | - Matthew S. Sachs
- Department of Biology, Texas A&M University, College Station, TX 77843, USA; (M.R.B.); (A.D.)
- Correspondence: ; Tel.: +1-(979)-845-5930
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12
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Li Z, Jing X, Yuan Y, Shui Y, Li S, Zhao Z, Deng B, Zhang W. In vitro and in vivo Activity of Phibilin Against Candida albicans. Front Microbiol 2022; 13:862834. [PMID: 35633688 PMCID: PMC9130856 DOI: 10.3389/fmicb.2022.862834] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 03/25/2022] [Indexed: 11/13/2022] Open
Abstract
The increase in the occurrence of antifungal-resistant Candida albicans infections necessitates more research to explore alternative effective and safe agents against this fungus. In this work, Phibilin, a new antimicrobial peptide obtained from Philomycus bilineatus and used in traditional Chinese medicine, effectively inhibits the growth and activities of C. albicans, including the clinical resistant strains. Phibilin is a fungicidal antimicrobial peptide that exhibited its antimicrobial effect against C. albicans mainly by disrupting the membrane and interacting with the DNA of the fungi. In particular, Phibilin induces the necrosis of C. albicans via the ROS-related pathway. Moreover, this antifungal compound inhibited the biofilm formation of C. albicans by preventing the development of hyphae in a dose-dependent manner. Furthermore, Phibilin and clotrimazole displayed a synergistic effect in inhibiting the growth of the fungi. In the mouse cutaneous infection model, Phibilin significantly inhibited the formation of skin abscesses and decreased the counts of C. albicans cells in the infected area. Overall, Phibilin is potentially an effective agent against skin infections caused by C. albicans.
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Affiliation(s)
- Zhongjie Li
- School of Basic Medical Sciences, Henan University of Science and Technology, Luoyang, China
| | - Xiaoyuan Jing
- School of Basic Medical Sciences, Henan University of Science and Technology, Luoyang, China
| | - Yaping Yuan
- School of Basic Medical Sciences, Henan University of Science and Technology, Luoyang, China
| | - Yingbin Shui
- School of Basic Medical Sciences, Henan University of Science and Technology, Luoyang, China
| | - Shasha Li
- School of Basic Medical Sciences, Henan University of Science and Technology, Luoyang, China
| | - Zhuoran Zhao
- School of Basic Medical Sciences, Henan University of Science and Technology, Luoyang, China
| | - Bo Deng
- School of Basic Medical Sciences, Henan University of Science and Technology, Luoyang, China
| | - Wenlu Zhang
- School of Basic Medical Sciences, Henan University of Science and Technology, Luoyang, China
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13
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Cantrell JM, Chung CH, Chandrasekaran S. Machine learning to design antimicrobial combination therapies: promises and pitfalls. Drug Discov Today 2022; 27:1639-1651. [DOI: 10.1016/j.drudis.2022.04.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 01/20/2022] [Accepted: 04/04/2022] [Indexed: 01/13/2023]
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14
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Progress Report: Antimicrobial Drug Discovery in the Resistance Era. Pharmaceuticals (Basel) 2022; 15:ph15040413. [PMID: 35455410 PMCID: PMC9030565 DOI: 10.3390/ph15040413] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 03/23/2022] [Accepted: 03/24/2022] [Indexed: 02/05/2023] Open
Abstract
Antibiotic resistance continues to be a most serious threat to public health. This situation demands that the scientific community increase their efforts for the discovery of alternative strategies to circumvent the problems associated with conventional small molecule therapeutics. The Global Antimicrobial Resistance and Use Surveillance System (GLASS) Report (published in June 2021) discloses the rapidly increasing number of bacterial infections that are mainly caused by antimicrobial-resistant bacteria. These concerns have initiated various government agencies and other organizations to educate the public regarding the appropriate use of antibiotics. This review discusses a brief highlight on the timeline of antimicrobial drug discovery with a special emphasis on the historical development of antimicrobial resistance. In addition, new antimicrobial targets and approaches, recent developments in drug screening, design, and delivery were covered. This review also discusses the emergence and roles of various antibiotic adjuvants and combination therapies while shedding light on current challenges and future perspectives. Overall, the emergence of resistant microbial strains has challenged drug discovery but their efforts to develop alternative technologies such as nanomaterials seem to be promising for the future.
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15
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Abstract
Systemic cryptococcosis is fatal without treatment. Globally, this disease kills 180,000 of the 225,000 infected people each year, even with the use of antifungal therapies. Currently, there is no vaccine to prevent cryptococcosis. Previously, we discovered that Znf2, a morphogenesis regulator that directs Cryptococcus yeast-to-hyphal transition, profoundly affects cryptococcal interaction with the host-overexpression of ZNF2 drives filamentous growth, attenuates cryptococcal virulence, and elicits protective host immune responses. Importantly, immunization with cryptococcal cells overexpressing ZNF2, either in live or heat-inactivated form, offers significant protection to the host from a subsequent challenge by the otherwise lethal wild-type H99 strain. We hypothesize that cellular components enriched in ZNF2oe cells are immunoprotective. Here, we discovered that serum from protected animals vaccinated with inactivated ZNF2oe cells recognizes cryptococcal antigens that reside within the capsule. Consistently, capsule is required for immunoprotection offered by ZNF2oe cells. Interestingly, the serum from protective animals recognizes antigens in both wild-type yeast cells and ZNF2oe cells, with higher abundance in the latter. Consequently, even the heat-inactivated wild-type cells become immunoprotective with an increased vaccination dose. We also found that disruption of a chromatin remodeling factor Brf1, which is important for initiation of filamentation by Znf2, reduces the antigen level in ZNF2oe cells. Deletion of BRF1 drastically reduces the protective effect of ZNF2oe cells in both live and heat-killed forms even though the ZNF2oebrf1Δ strain itself is avirulent. Collectively, our findings underscore the importance of identifying the subset of cryptococcal surface factors that are beneficial in host protection. IMPORTANCE Cryptococcosis claims close to 200,000 lives annually. There is no vaccine clinically available for this fungal disease. Many avirulent mutant strains do not provide protection against cryptococcosis. We previously discovered that hyphal ZNF2oe strains elicit protective host immune responses both in the live and heat-inactivated forms. Here we seek to understand the mechanism underlying the host protection provided by ZNF2oe cells. We discovered increased accumulation of antigens located within the caspusle of ZNF2oe cells and consequently the requirement of the capsule for ZNF2oe strain-elicited host protection. Furthermore, genetically blocking the ability of ZNF2oe cells to grow in the hyphal form significantly reduces antigen accumulation and impairs the ability of ZNF2oe strain to provide host protection. Our findings highlight the importance of identifying the Znf2-regulated capsular surface factors that are fundamental in host protection.
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16
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Liu L, Jiang T, Zhou J, Mei Y, Li J, Tan J, Wei L, Li J, Peng Y, Chen C, Liu N, Wang H. Repurposing the FDA-approved anticancer agent ponatinib as a fluconazole potentiator by suppression of multidrug efflux and Pma1 expression in a broad spectrum of yeast species. Microb Biotechnol 2022; 15:482-498. [PMID: 33955652 PMCID: PMC8867973 DOI: 10.1111/1751-7915.13814] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 03/23/2021] [Accepted: 03/24/2021] [Indexed: 11/29/2022] Open
Abstract
Fungal infections have emerged as a major global threat to human health because of the increasing incidence and mortality rates every year. The emergence of drug resistance and limited arsenal of antifungal agents further aggravates the current situation resulting in a growing challenge in medical mycology. Here, we identified that ponatinib, an FDA-approved antitumour drug, significantly enhanced the activity of the azole fluconazole, the most widely used antifungal drug. Further detailed investigation of ponatinib revealed that its combination with fluconazole displayed broad-spectrum synergistic interactions against a variety of human fungal pathogens such as Candida albicans, Saccharomyces cerevisiae and Cryptococcus neoformans. Mechanistic insights into the mode of action unravelled that ponatinib reduced the efflux of fluconazole via Pdr5 and suppressed the expression of the proton pump, Pma1. Taken together, our study identifies ponatinib as a novel antifungal that enhances drug activity of fluconazole against diverse fungal pathogens.
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Affiliation(s)
- Lin Liu
- State Key Laboratory of Oncogenes and Related GenesCenter for Single‐Cell OmicsSchool of Public HealthShanghai Jiao Tong University School of MedicineShanghai200025China
| | - Tong Jiang
- Center for MicrobesDevelopment and HealthKey Laboratory of Molecular Virology and ImmunologyInstitut Pasteur of ShanghaiChinese Academy of SciencesShanghai200031China
- University of Chinese Academy of SciencesBeijingChina
| | - Jia Zhou
- State Key Laboratory of Oncogenes and Related GenesCenter for Single‐Cell OmicsSchool of Public HealthShanghai Jiao Tong University School of MedicineShanghai200025China
| | - Yikun Mei
- State Key Laboratory of Oncogenes and Related GenesCenter for Single‐Cell OmicsSchool of Public HealthShanghai Jiao Tong University School of MedicineShanghai200025China
| | - Jinyang Li
- State Key Laboratory of Oncogenes and Related GenesCenter for Single‐Cell OmicsSchool of Public HealthShanghai Jiao Tong University School of MedicineShanghai200025China
| | - Jingcong Tan
- State Key Laboratory of Oncogenes and Related GenesCenter for Single‐Cell OmicsSchool of Public HealthShanghai Jiao Tong University School of MedicineShanghai200025China
| | - Luqi Wei
- State Key Laboratory of Oncogenes and Related GenesCenter for Single‐Cell OmicsSchool of Public HealthShanghai Jiao Tong University School of MedicineShanghai200025China
| | - Jingquan Li
- State Key Laboratory of Oncogenes and Related GenesCenter for Single‐Cell OmicsSchool of Public HealthShanghai Jiao Tong University School of MedicineShanghai200025China
| | - Yibing Peng
- Department of Laboratory MedicineRuijin HospitalShanghai Jiao Tong University School of MedicineNo. 197 Ruijin ER RoadShanghai200025China
- Faculty of Medical Laboratory ScienceShanghai Jiao Tong University School of MedicineNo. 197 Ruijin ER RoadShanghai200025China
| | - Changbin Chen
- Center for MicrobesDevelopment and HealthKey Laboratory of Molecular Virology and ImmunologyInstitut Pasteur of ShanghaiChinese Academy of SciencesShanghai200031China
- The Nanjing Unicorn Academy of InnovationInstitut Pasteur of ShanghaiChinese Academy of SciencesNanjing211135China
| | - Ning‐Ning Liu
- State Key Laboratory of Oncogenes and Related GenesCenter for Single‐Cell OmicsSchool of Public HealthShanghai Jiao Tong University School of MedicineShanghai200025China
| | - Hui Wang
- State Key Laboratory of Oncogenes and Related GenesCenter for Single‐Cell OmicsSchool of Public HealthShanghai Jiao Tong University School of MedicineShanghai200025China
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17
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Fu C, Beattie SR, Jezewski AJ, Robbins N, Whitesell L, Krysan DJ, Cowen LE. Genetic analysis of Hsp90 function in Cryptococcus neoformans highlights key roles in stress tolerance and virulence. Genetics 2022; 220:iyab164. [PMID: 34849848 PMCID: PMC8733452 DOI: 10.1093/genetics/iyab164] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 09/27/2021] [Indexed: 11/13/2022] Open
Abstract
The opportunistic human fungal pathogen Cryptococcus neoformans has tremendous impact on global health, causing 181,000 deaths annually. Current treatment options are limited, and the frequent development of drug resistance exacerbates the challenge of managing invasive cryptococcal infections. In diverse fungal pathogens, the essential molecular chaperone Hsp90 governs fungal survival, drug resistance, and virulence. Therefore, targeting this chaperone has emerged as a promising approach to combat fungal infections. However, the role of Hsp90 in supporting C. neoformans pathogenesis remains largely elusive due to a lack of genetic characterization. To help dissect the functions of Hsp90 in C. neoformans, we generated a conditional expression strain in which HSP90 is under control of the copper-repressible promoter CTR4-2. Addition of copper to culture medium depleted Hsp90 transcript and protein levels in this strain, resulting in compromised fungal growth at host temperature; increased sensitivity to stressors, including the azole class of antifungals; altered C. neoformans morphology; and impaired melanin production. Finally, leveraging the fact that copper concentrations vary widely in different mouse tissues, we demonstrated attenuated virulence for the CTR4-2p-HSP90 mutant specifically in an inhalation model of Cryptococcus infection. During invasion and establishment of infection in this mouse model, the pathogen is exposed to the relatively high copper concentrations found in the lung as compared to blood. Overall, this work generates a tractable genetic system to study the role of Hsp90 in supporting the pathogenicity of C. neoformans and provides proof-of-principle that targeting Hsp90 holds great promise as a strategy to control cryptococcal infection.
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Affiliation(s)
- Ci Fu
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Sarah R Beattie
- Departments of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Andrew J Jezewski
- Departments of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Luke Whitesell
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Damian J Krysan
- Departments of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Microbiology/Immunology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
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18
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Lin J, Zangi M, Kumar TVH, Shakar Reddy M, Reddy LVR, Sadhukhan SK, Bradley DP, Moreira-Walsh B, Edwards TC, O’Dea AT, Tavis JE, Meyers MJ, Donlin MJ. Synthetic Derivatives of Ciclopirox are Effective Inhibitors of Cryptococcus neoformans. ACS OMEGA 2021; 6:8477-8487. [PMID: 33817509 PMCID: PMC8015083 DOI: 10.1021/acsomega.1c00273] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 02/09/2021] [Indexed: 05/04/2023]
Abstract
Opportunistic fungal infections caused by Cryptococcus neoformans are a significant source of mortality in immunocompromised patients. They are challenging to treat because of a limited number of antifungal drugs, and novel and more effective anticryptococcal therapies are needed. Ciclopirox olamine, a N-hydroxypyridone, has been in use as an approved therapeutic agent for the treatment of topical fungal infections for more than two decades. It is a fungicide, with broad activity across multiple fungal species. We synthesized 10 N-hydroxypyridone derivatives to develop an initial structure-activity understanding relative to efficacy as a starting point for the development of systemic antifungals. We screened the derivatives for antifungal activity against C. neoformans and Cryptococcus gattii and counter-screened for specificity in Candida albicans and two Malassezia species. Eight of the ten show inhibition at 1-3 μM concentration (0.17-0.42 μg per mL) in both Cryptococcus species and in C. albicans, but poor activity in the Malassezia species. In C. neoformans, the N-hydroxypyridones are fungicides, are not antagonistic with either fluconazole or amphotericin B, and are synergistic with multiple inhibitors of the mitochondrial electron transport chain. They appear to function primarily by chelating iron within the active site of iron-dependent enzymes. This preliminary structure-activity relationship points to the need for a lipophilic functional group at position six of the N-hydroxypyridone ring and identifies positions four and six as sites where further substitution may be tolerated. These molecules provide a clear starting point for future optimization for efficacy and target identification.
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Affiliation(s)
- Jeffrey Lin
- Department
of Biology, Saint Louis University, 3507 Laclede Avenue, St. Louis, Missouri 63103, United States
| | - Maryam Zangi
- Department
of Chemistry, Saint Louis University, 3501 Laclede Avenue, St. Louis, Missouri 63103, United States
| | | | - Makala Shakar Reddy
- Medicinal
Chemistry Division, Albany Molecular Research
Inc., MN Park, Turkpally
Shamirpet Mandal, Genome Valley, Hyderabad 500078, India
| | - Lingala Vijaya Raghava Reddy
- Medicinal
Chemistry Division, Albany Molecular Research
Inc., MN Park, Turkpally
Shamirpet Mandal, Genome Valley, Hyderabad 500078, India
| | - Subir Kumar Sadhukhan
- Medicinal
Chemistry Division, Albany Molecular Research
Inc., MN Park, Turkpally
Shamirpet Mandal, Genome Valley, Hyderabad 500078, India
| | - Daniel P. Bradley
- Department
of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, 1100 South Grand Blvd., St. Louis, Missouri 63104, United States
- Institute
for Drug and Biotherapeutic Innovation, Saint Louis University, St. Louis, Missouri 63103, United States
| | - Brenda Moreira-Walsh
- Edward
A. Doisy Department of Biochemistry, Saint
Louis University School of Medicine, 1100 South Grand Blvd., St. Louis, Missouri 63104, United
States
| | - Tiffany C. Edwards
- Department
of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, 1100 South Grand Blvd., St. Louis, Missouri 63104, United States
| | - Austin T. O’Dea
- Department
of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, 1100 South Grand Blvd., St. Louis, Missouri 63104, United States
| | - John E. Tavis
- Department
of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, 1100 South Grand Blvd., St. Louis, Missouri 63104, United States
- Institute
for Drug and Biotherapeutic Innovation, Saint Louis University, St. Louis, Missouri 63103, United States
| | - Marvin J. Meyers
- Department
of Chemistry, Saint Louis University, 3501 Laclede Avenue, St. Louis, Missouri 63103, United States
- Institute
for Drug and Biotherapeutic Innovation, Saint Louis University, St. Louis, Missouri 63103, United States
| | - Maureen J. Donlin
- Edward
A. Doisy Department of Biochemistry, Saint
Louis University School of Medicine, 1100 South Grand Blvd., St. Louis, Missouri 63104, United
States
- Institute
for Drug and Biotherapeutic Innovation, Saint Louis University, St. Louis, Missouri 63103, United States
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19
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Liu Y, Tong Z, Shi J, Li R, Upton M, Wang Z. Drug repurposing for next-generation combination therapies against multidrug-resistant bacteria. Theranostics 2021; 11:4910-4928. [PMID: 33754035 PMCID: PMC7978324 DOI: 10.7150/thno.56205] [Citation(s) in RCA: 84] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 01/29/2021] [Indexed: 12/12/2022] Open
Abstract
Antimicrobial resistance has been a global health challenge that threatens our ability to control and treat life-threatening bacterial infections. Despite ongoing efforts to identify new drugs or alternatives to antibiotics, no new classes of antibiotic or their alternatives have been clinically approved in the last three decades. A combination of antibiotics and non-antibiotic compounds that could inhibit bacterial resistance determinants or enhance antibiotic activity offers a sustainable and effective strategy to confront multidrug-resistant bacteria. In this review, we provide a brief overview of the co-evolution of antibiotic discovery and the development of bacterial resistance. We summarize drug-drug interactions and uncover the art of repurposing non-antibiotic drugs as potential antibiotic adjuvants, including discussing classification and mechanisms of action, as well as reporting novel screening platforms. A pathogen-by-pathogen approach is then proposed to highlight the critical value of drug repurposing and its therapeutic potential. Finally, general advantages, challenges and development trends of drug combination strategy are discussed.
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Affiliation(s)
- Yuan Liu
- College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Joint International Research Laboratory of Agriculture and Agri-Product Safety, the Ministry of Education of China, Yangzhou University, Yangzhou, Jiangsu, China
- Institute of Comparative Medicine, Yangzhou University, Yangzhou, Jiangsu, China
| | - Ziwen Tong
- College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China
| | - Jingru Shi
- College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China
| | - Ruichao Li
- College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Joint International Research Laboratory of Agriculture and Agri-Product Safety, the Ministry of Education of China, Yangzhou University, Yangzhou, Jiangsu, China
- Institute of Comparative Medicine, Yangzhou University, Yangzhou, Jiangsu, China
| | - Mathew Upton
- School of Biomedical Sciences, University of Plymouth, Drake Circus, Plymouth, UK
| | - Zhiqiang Wang
- College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Joint International Research Laboratory of Agriculture and Agri-Product Safety, the Ministry of Education of China, Yangzhou University, Yangzhou, Jiangsu, China
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20
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Stempinski PR, Zielinski JM, Dbouk NH, Huey ES, McCormack EC, Rubin AM, Chandrasekaran S, Kozubowski L. Genetic contribution to high temperature tolerance in Cryptococcus neoformans. Genetics 2021; 217:1-15. [PMID: 33683363 PMCID: PMC8045695 DOI: 10.1093/genetics/iyaa009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 10/24/2020] [Indexed: 11/12/2022] Open
Abstract
The human fungal pathogen Cryptococcus neoformans relies on a complex signaling network for the adaptation and survival at the host temperature. Protein phosphatase calcineurin is central to proliferation at 37°C but its exact contributions remain ill-defined. To better define genetic contributions to the C. neoformans temperature tolerance, 4031 gene knockouts were screened for genes essential at 37°C and under conditions that keep calcineurin inactive. Identified 83 candidate strains, potentially sensitive to 37°C, were subsequently subject to technologically simple yet robust assay, in which cells are exposed to a temperature gradient. This has resulted in identification of 46 genes contributing to the maximum temperature at which C. neoformans can proliferate (Tmax). The 46 mutants, characterized by a range of Tmax on drug-free media, were further assessed for Tmax under conditions that inhibit calcineurin, which led to identification of several previously uncharacterized knockouts exhibiting synthetic interaction with the inhibition of calcineurin. A mutant that lacked septin Cdc11 was among those with the lowest Tmax and failed to proliferate in the absence of calcineurin activity. To further define connections with calcineurin and the role for septins in high temperature growth, the 46 mutants were tested for cell morphology at 37°C and growth in the presence of agents disrupting cell wall and cell membrane. Mutants sensitive to calcineurin inhibition were tested for synthetic lethal interaction with deletion of the septin-encoding CDC12 and the localization of the septin Cdc3-mCherry. The analysis described here pointed to previously uncharacterized genes that were missed in standard growth assays indicating that the temperature gradient assay is a valuable complementary tool for elucidating the genetic basis of temperature range at which microorganisms proliferate.
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Affiliation(s)
- Piotr R Stempinski
- Department of Genetics & Biochemistry, Eukaryotic Pathogens Innovation Center (EPIC), Clemson University, Clemson, SC 29634, USA
| | - Jessica M Zielinski
- Department of Genetics & Biochemistry, Eukaryotic Pathogens Innovation Center (EPIC), Clemson University, Clemson, SC 29634, USA
| | - Nadir H Dbouk
- Department of Biology, Furman University, Greenville, SC 29613, USA
| | - Elizabeth S Huey
- Department of Genetics & Biochemistry, Eukaryotic Pathogens Innovation Center (EPIC), Clemson University, Clemson, SC 29634, USA
| | - Ellen C McCormack
- Department of Genetics & Biochemistry, Eukaryotic Pathogens Innovation Center (EPIC), Clemson University, Clemson, SC 29634, USA
| | - Alexander M Rubin
- Department of Genetics & Biochemistry, Eukaryotic Pathogens Innovation Center (EPIC), Clemson University, Clemson, SC 29634, USA
| | | | - Lukasz Kozubowski
- Department of Genetics & Biochemistry, Eukaryotic Pathogens Innovation Center (EPIC), Clemson University, Clemson, SC 29634, USA
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21
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LeBlanc EV, Shekhar-Guturja T, Whitesell L, Cowen LE. Fluorescence Polarization-Based Measurement of Protein-Ligand Interaction in Fungal Cell Lysates. Curr Protoc 2021; 1:e17. [PMID: 33484500 DOI: 10.1002/cpz1.17] [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: 11/10/2022]
Abstract
Fungi infect over a billion people worldwide and contribute substantially to human morbidity and mortality despite all available therapies. New antifungal drugs are urgently needed. Decades of study have revealed numerous protein targets of potential therapeutic interest for which potent, fungal-selective ligands remain to be discovered and developed. To measure the binding of diverse small molecule ligands to their larger protein targets, fluorescence polarization (FP) can provide a robust, inexpensive approach. The protocols in this article provide detailed guidance for developing FP-based assays capable of measuring binding affinity in whole cell lysates without the need for purification of the target protein. Applications include screening of libraries to identify novel ligands and the definition of structure-activity relationships to aid development of compounds with improved target affinity and fungal selectivity. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Use of saturation binding curves to optimize tracer and lysate protein concentrations Basic Protocol 2: Establishment of competition binding experiments Support Protocol 1: Preparation of fungal cell lysates Support Protocol 2: Preparation of human HepG2 cell lysate.
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Affiliation(s)
- Emmanuelle V LeBlanc
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | | | - Luke Whitesell
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
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22
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Treatment strategies for cryptococcal infection: challenges, advances and future outlook. Nat Rev Microbiol 2021; 19:454-466. [PMID: 33558691 PMCID: PMC7868659 DOI: 10.1038/s41579-021-00511-0] [Citation(s) in RCA: 144] [Impact Index Per Article: 48.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/07/2021] [Indexed: 01/31/2023]
Abstract
Cryptococcus spp., in particular Cryptococcus neoformans and Cryptococcus gattii, have an enormous impact on human health worldwide. The global burden of cryptococcal meningitis is almost a quarter of a million cases and 181,000 deaths annually, with mortality rates of 100% if infections remain untreated. Despite these alarming statistics, treatment options for cryptococcosis remain limited, with only three major classes of drugs approved for clinical use. Exacerbating the public health burden is the fact that the only new class of antifungal drugs developed in decades, the echinocandins, displays negligible antifungal activity against Cryptococcus spp., and the efficacy of the remaining therapeutics is hampered by host toxicity and pathogen resistance. Here, we describe the current arsenal of antifungal agents and the treatment strategies employed to manage cryptococcal disease. We further elaborate on the recent advances in our understanding of the intrinsic and adaptive resistance mechanisms that are utilized by Cryptococcus spp. to evade therapeutic treatments. Finally, we review potential therapeutic strategies, including combination therapy, the targeting of virulence traits, impairing stress response pathways and modulating host immunity, to effectively treat infections caused by Cryptococcus spp. Overall, understanding of the mechanisms that regulate anti-cryptococcal drug resistance, coupled with advances in genomics technologies and high-throughput screening methodologies, will catalyse innovation and accelerate antifungal drug discovery.
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23
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Xue A, Robbins N, Cowen LE. Advances in fungal chemical genomics for the discovery of new antifungal agents. Ann N Y Acad Sci 2020; 1496:5-22. [PMID: 32860238 DOI: 10.1111/nyas.14484] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 08/09/2020] [Accepted: 08/13/2020] [Indexed: 12/15/2022]
Abstract
Invasive fungal infections have escalated from a rare curiosity to a major cause of human mortality around the globe. This is in part due to a scarcity in the number of antifungal drugs available to combat mycotic disease, making the discovery of novel bioactive compounds and determining their mode of action of utmost importance. The development and application of chemical genomic assays using the model yeast Saccharomyces cerevisiae has provided powerful methods to identify the mechanism of action of diverse molecules in a living cell. Furthermore, complementary assays are continually being developed in fungal pathogens, most notably Candida albicans and Cryptococcus neoformans, to elucidate compound mechanism of action directly in the pathogen of interest. Collectively, the suite of chemical genetic assays that have been developed in multiple fungal species enables the identification of candidate drug target genes, as well as genes involved in buffering drug target pathways, and genes involved in general cellular responses to small molecules. In this review, we examine current yeast chemical genomic assays and highlight how such resources provide powerful tools that can be utilized to bolster the antifungal pipeline.
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Affiliation(s)
- Alice Xue
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
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24
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Lawrence CL, Okoh AO, Vishwapathi V, McKenna ST, Critchley ME, Smith RB. N-alkylated linear heptamethine polyenes as potent non-azole leads against Candida albicans fungal infections. Bioorg Chem 2020; 102:104070. [PMID: 32682157 DOI: 10.1016/j.bioorg.2020.104070] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 06/30/2020] [Accepted: 07/02/2020] [Indexed: 02/07/2023]
Abstract
In this study, eighteen heptamethine dyes were synthesised and their antifungal activities were evaluated against three clinically relevant yeast species.. The eighteen dyes were placed within classes based on their core subunit i.e. 2,3,3-trimethylindolenine (5a-f), 1,1,2-trimethyl-1H-benzo[e]indole (6a-f), or 2-methylbenzothiazole (7a-f). The results presented herein imply that the three families of cyanine dyes, in particular compounds 5a-f, show high potential as selective scaffolds to treat C. albicans infections. This opens up the opportunity for further optimisation and investigation of this class compounds for potential antifungal treatment.
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Affiliation(s)
- Clare L Lawrence
- UCLan Research Centre for Drug Design and Development, School of Pharmacy and Biomedical Sciences, University of Central Lancashire, Preston PR1 2HE, UK.
| | - Adeyi Okoh Okoh
- UCLan Research Centre for Smart Materials, University of Central Lancashire, Preston PR1 2HE, UK
| | - Vinod Vishwapathi
- UCLan Research Centre for Smart Materials, University of Central Lancashire, Preston PR1 2HE, UK
| | - Sean T McKenna
- UCLan Research Centre for Smart Materials, University of Central Lancashire, Preston PR1 2HE, UK
| | - Megan E Critchley
- UCLan Research Centre for Smart Materials, University of Central Lancashire, Preston PR1 2HE, UK
| | - Robert B Smith
- UCLan Research Centre for Smart Materials, University of Central Lancashire, Preston PR1 2HE, UK.
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25
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McGuirl MR, Smith SP, Sandstede B, Ramachandran S. Detecting Shared Genetic Architecture Among Multiple Phenotypes by Hierarchical Clustering of Gene-Level Association Statistics. Genetics 2020; 215:511-529. [PMID: 32245788 PMCID: PMC7268989 DOI: 10.1534/genetics.120.303096] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 03/31/2020] [Indexed: 12/31/2022] Open
Abstract
Emerging large-scale biobanks pairing genotype data with phenotype data present new opportunities to prioritize shared genetic associations across multiple phenotypes for molecular validation. Past research, by our group and others, has shown gene-level tests of association produce biologically interpretable characterization of the genetic architecture of a given phenotype. Here, we present a new method, Ward clustering to identify Internal Node branch length outliers using Gene Scores (WINGS), for identifying shared genetic architecture among multiple phenotypes. The objective of WINGS is to identify groups of phenotypes, or "clusters," sharing a core set of genes enriched for mutations in cases. We validate WINGS using extensive simulation studies and then combine gene-level association tests with WINGS to identify shared genetic architecture among 81 case-control and seven quantitative phenotypes in 349,468 European-ancestry individuals from the UK Biobank. We identify eight prioritized phenotype clusters and recover multiple published gene-level associations within prioritized clusters.
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Affiliation(s)
- Melissa R McGuirl
- Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912
| | - Samuel Pattillo Smith
- Center for Computational Molecular Biology, Brown University, Providence, Rhode Island 02912
- Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island 02912
| | - Björn Sandstede
- Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912
- Data Science Initiative, Brown University, Providence, Rhode Island 02912
| | - Sohini Ramachandran
- Center for Computational Molecular Biology, Brown University, Providence, Rhode Island 02912
- Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island 02912
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26
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Wambaugh MA, Denham ST, Ayala M, Brammer B, Stonhill MA, Brown JC. Synergistic and antagonistic drug interactions in the treatment of systemic fungal infections. eLife 2020; 9:54160. [PMID: 32367801 PMCID: PMC7200157 DOI: 10.7554/elife.54160] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 03/31/2020] [Indexed: 12/11/2022] Open
Abstract
Invasive fungal infections cause 1.6 million deaths annually, primarily in immunocompromised individuals. Mortality rates are as high as 90% due to limited treatments. The azole class antifungal, fluconazole, is widely available and has multi-species activity but only inhibits growth instead of killing fungal cells, necessitating long treatments. To improve treatment, we used our novel high-throughput method, the overlap2 method (O2M) to identify drugs that interact with fluconazole, either increasing or decreasing efficacy. We identified 40 molecules that act synergistically (amplify activity) and 19 molecules that act antagonistically (decrease efficacy) when combined with fluconazole. We found that critical frontline beta-lactam antibiotics antagonize fluconazole activity. A promising fluconazole-synergizing anticholinergic drug, dicyclomine, increases fungal cell permeability and inhibits nutrient intake when combined with fluconazole. In vivo, this combination doubled the time-to-endpoint of mice with Cryptococcus neoformans meningitis. Thus, our ability to rapidly identify synergistic and antagonistic drug interactions can potentially alter the patient outcomes. Individuals with weakened immune systems – such as recipients of organ transplants – can fall prey to illnesses caused by fungi that are harmless to most people. These infections are difficult to manage because few treatments exist to fight fungi, and many have severe side effects. Antifungal drugs usually slow the growth of fungi cells rather than kill them, which means that patients must remain under treatment for a long time, or even for life. One way to boost efficiency and combat resistant infections is to combine antifungal treatments with drugs that work in complementary ways: the drugs strengthen each other’s actions, and together they can potentially kill the fungus rather than slow its progression. However, not all drug combinations are helpful. In fact, certain drugs may interact in ways that make treatment less effective. This is particularly concerning because people with weakened immune systems often take many types of medications. Here, Wambaugh et al. harnessed a new high-throughput system to screen how 2,000 drugs (many of which already approved to treat other conditions) affected the efficiency of a common antifungal called fluconazole. This highlighted 19 drugs that made fluconazole less effective, some being antibiotics routinely used to treat patients with weakened immune systems. On the other hand, 40 drugs boosted the efficiency of fluconazole, including dicyclomine, a compound currently used to treat inflammatory bowel syndrome. In fact, pairing dicyclomine and fluconazole more than doubled the survival rate of mice with severe fungal infections. The combined treatment could target many species of harmful fungi, even those that had become resistant to fluconazole alone. The results by Wambaugh et al. point towards better treatments for individuals with serious fungal infections. Drugs already in circulation for other conditions could be used to boost the efficiency of fluconazole, while antibiotics that do not decrease the efficiency of this medication should be selected to treat at-risk patients.
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Affiliation(s)
- Morgan A Wambaugh
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, United States
| | - Steven T Denham
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, United States
| | - Magali Ayala
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, United States
| | - Brianna Brammer
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, United States
| | - Miekan A Stonhill
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, United States
| | - Jessica Cs Brown
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, United States
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Abstract
The human meningitis fungal pathogen, Cryptococcus neoformans, contains the atypical yeast AP-1-like protein Yap1. Yap1 lacks an N-terminal cysteine-rich domain (n-CRD), which is present in other fungal Yap1 orthologs, but has a C-terminal cysteine-rich domain (c-CRD). However, the role of c-CRD and its regulatory mechanism remain unknown. Here, we report that Yap1 is transcriptionally regulated in response to oxidative, osmotic, and membrane-destabilizing stresses partly in an Mpk1-dependent manner, supporting its role in stress resistance. The c-CRD domain contributed to the role of Yap1 only in resistance to certain oxidative stresses and azole drugs but not in other cellular functions. Yap1 has a minor role in the survival of C. neoformans in a murine model of systemic cryptococcosis. AP-1-like transcription factors play evolutionarily conserved roles as redox sensors in eukaryotic oxidative stress responses. In this study, we aimed to elucidate the regulatory mechanism of an atypical yeast AP-1-like protein, Yap1, in the stress response and virulence of Cryptococcus neoformans. YAP1 expression was induced and involved not only by oxidative stresses, such as H2O2 and diamide, but also by other environmental stresses, such as osmotic and membrane-destabilizing stresses. Yap1 was distributed throughout both the cytoplasm and the nucleus under basal conditions and more enriched within the nucleus in response to diamide but not to other stresses. Deletion of the C-terminal cysteine-rich domain (c-CRD), where the nuclear export signal resides, increased nuclear enrichment of Yap1 under basal conditions and altered resistance to oxidative stresses but did not affect the role of Yap1 in other stress responses and cellular functions. As a potential upstream regulator of Yap1, we discovered that Mpk1 is positively involved, but Hog1 is mostly dispensable. Pleiotropic roles for Yap1 in diverse biological processes were supported by transcriptome data showing that 162 genes are differentially regulated by Yap1, with further analysis revealing that Yap1 promotes cellular resistance to toxic cellular metabolites produced during glycolysis, such as methylglyoxal. Finally, we demonstrated that Yap1 plays a minor role in the survival of C. neoformans within hosts. IMPORTANCE The human meningitis fungal pathogen, Cryptococcus neoformans, contains the atypical yeast AP-1-like protein Yap1. Yap1 lacks an N-terminal cysteine-rich domain (n-CRD), which is present in other fungal Yap1 orthologs, but has a C-terminal cysteine-rich domain (c-CRD). However, the role of c-CRD and its regulatory mechanism remain unknown. Here, we report that Yap1 is transcriptionally regulated in response to oxidative, osmotic, and membrane-destabilizing stresses partly in an Mpk1-dependent manner, supporting its role in stress resistance. The c-CRD domain contributed to the role of Yap1 only in resistance to certain oxidative stresses and azole drugs but not in other cellular functions. Yap1 has a minor role in the survival of C. neoformans in a murine model of systemic cryptococcosis.
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mSphere of Influence: the Power of Yeast Genetics Still Going Strong! mSphere 2019; 4:4/5/e00647-19. [PMID: 31578250 PMCID: PMC6796973 DOI: 10.1128/msphere.00647-19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Felipe Santiago-Tirado studies the cell biology of cryptococcal infections. Felipe Santiago-Tirado studies the cell biology of cryptococcal infections. In this mSphere of Influence article, he reflects on how the papers “Systematic Genetic Analysis of Virulence in the Human Fungal Pathogen Cryptococcus neoformans” (https://doi.org/10.1016/j.cell.2008.07.046) and “Unraveling the Biology of a Fungal Meningitis Pathogen Using Chemical Genetics” (https://doi.org/10.1016/j.cell.2014.10.044) by the Noble and Madhani groups influenced his thinking by showcasing the various modern applications of yeast genetics in an organism where genetic manipulation was difficult.
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Maryam M, Fu MS, Alanio A, Camacho E, Goncalves DS, Faneuff EE, Grossman NT, Casadevall A, Coelho C. The enigmatic role of fungal annexins: the case of Cryptococcus neoformans. MICROBIOLOGY-SGM 2019; 165:852-862. [PMID: 31140968 DOI: 10.1099/mic.0.000815] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Annexins are multifunctional proteins that bind to phospholipid membranes in a calcium-dependent manner. Annexins play a myriad of critical and well-characterized roles in mammals, ranging from membrane repair to vesicular secretion. The role of annexins in the kingdoms of bacteria, protozoa and fungi have been largely overlooked. The fact that there is no known homologue of annexins in the yeast model organism Saccharomyces cerevisiae may contribute to this gap in knowledge. However, annexins are found in most medically important fungal pathogens, with the notable exception of Candida albicans. In this study we evaluated the function of the one annexin gene in Cryptococcus neoformans, a causative agent of cryptococcosis. This gene CNAG_02415, is annotated in the C. neoformans genome as a target of calcineurin through its transcription factor Crz1, and we propose to update its name to cryptococcal annexin, AnnexinC1. C. neoformans strains deleted for AnnexinC1 revealed no difference in survival after exposure to various chemical stressors relative to wild-type strain, as well as no major alteration in virulence or mating. The only alteration observed in strains deleted for AnnexinC1 was a small increase in the titan cells' formation in vitro. The preservation of annexins in many different fungal species suggests an important function, and therefore the lack of a strong phenotype for annexin-deficient C. neoformans indicates either the presence of redundant genes that can compensate for the absence of AnnexinC1 function or novel functions not revealed by standard assays of cell function and pathogenicity.
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Affiliation(s)
- Maria Maryam
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore MD, USA
| | - Man Shun Fu
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore MD, USA
| | - Alexandre Alanio
- Institut Pasteur, Molecular Mycology Unit, CNRS UMR2000, Université Paris Diderot, Sorbonne Paris Cité ; Laboratoire de Parasitologie-Mycologie, Hôpital Saint-Louis, Groupe Hospitalier Lariboisière, Saint-Louis, Fernand Widal, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France.,W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore MD, USA
| | - Emma Camacho
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore MD, USA
| | - Diego S Goncalves
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore MD, USA.,Universidade Federal Fluminense, Rio Janeiro, Brazil
| | - Eden E Faneuff
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore MD, USA.,Department of Biological Sciences, California State Polytechnic University, Pomona CA, USA
| | - Nina T Grossman
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore MD, USA
| | - Arturo Casadevall
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore MD, USA
| | - Carolina Coelho
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore MD, USA.,College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK.,Medical Research Council Centre for Medical Mycology, Institute of Medical Sciences, University of Aberdeen, Ashgrove Road West, Aberdeen AB252ZD, UK
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Cokol M, Li C, Chandrasekaran S. Chemogenomic model identifies synergistic drug combinations robust to the pathogen microenvironment. PLoS Comput Biol 2018; 14:e1006677. [PMID: 30596642 PMCID: PMC6329523 DOI: 10.1371/journal.pcbi.1006677] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 01/11/2019] [Accepted: 11/27/2018] [Indexed: 01/31/2023] Open
Abstract
Antibiotics need to be effective in diverse environments in vivo. However, the pathogen microenvironment can have a significant impact on antibiotic potency. Further, antibiotics are increasingly used in combinations to combat resistance, yet, the effect of microenvironments on drug-combination efficacy is unknown. To exhaustively explore the impact of diverse microenvironments on drug-combinations, here we develop a computational framework—Metabolism And GENomics-based Tailoring of Antibiotic regimens (MAGENTA). MAGENTA uses chemogenomic profiles of individual drugs and metabolic perturbations to predict synergistic or antagonistic drug-interactions in different microenvironments. We uncovered antibiotic combinations with robust synergy across nine distinct environments against both E. coli and A. baumannii by searching through 2556 drug-combinations of 72 drugs. MAGENTA also accurately predicted the change in efficacy of bacteriostatic and bactericidal drug-combinations during growth in glycerol media, which we confirmed experimentally in both microbes. Our approach identified genes in glycolysis and glyoxylate pathway as top predictors of synergy and antagonism respectively. Our systems approach enables tailoring of antibiotic therapies based on the pathogen microenvironment. The antibiotic resistance epidemic has created a pressing need to understand factors that influence antibiotic efficacy. An often-overlooked factor in the search for new treatments is the pathogen environment. Understanding the differences in pathogen sensitivity to antibiotics in lab conditions versus inside the host is necessary for translating new discoveries into the clinic. Hence, we experimentally measured the sensitivity of E. coli to drugs and drug combinations in different metabolic conditions. Our data revealed that the environment dramatically changes treatment potency. Each antibiotic class was affected uniquely by each metabolic condition. The large number of metabolic conditions inside the host greatly complicates the identification of effective therapies. To address this challenge, we present a computational approach called MAGENTA that accurately predicted efficacy of antibiotic regimens in different conditions, which we confirmed experimentally. Furthermore, we show that MAGENTA can be applied to other bacterial pathogens such as A. baumannii and M. tuberculosis without the need for generating expensive data in each organism. MAGENTA accurately predicted efficacy in the pathogen A. baumannii using data from E. coli by identifying genes that are common between the two bacteria. Our study revealed the significant yet predictable impact of environment on drug combination potency.
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Affiliation(s)
- Murat Cokol
- Axcella Health, Cambridge, Massachusetts, United States of America
- Laboratory of Systems Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
- Faculty of Engineering and Natural Sciences, Sabanci University, Istanbul, Turkey
- * E-mail: (SC); (MC)
| | - Chen Li
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Sriram Chandrasekaran
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail: (SC); (MC)
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31
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Annunziato G, Giovati L, Angeli A, Pavone M, Del Prete S, Pieroni M, Capasso C, Bruno A, Conti S, Magliani W, Supuran CT, Costantino G. Discovering a new class of antifungal agents that selectively inhibits microbial carbonic anhydrases. J Enzyme Inhib Med Chem 2018; 33:1537-1544. [PMID: 30284487 PMCID: PMC6179086 DOI: 10.1080/14756366.2018.1516652] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Infections caused by pathogens resistant to the available antimicrobial treatments represent nowadays a threat to global public health. Recently, it has been demonstrated that carbonic anhydrases (CAs) are essential for the growth of many pathogens and their inhibition leads to growth defects. Principal drawbacks in using CA inhibitors (CAIs) as antimicrobial agents are the side effects due to the lack of selectivity toward human CA isoforms. Herein we report a new class of CAIs, which preferentially interacts with microbial CA active sites over the human ones. The mechanism of action of these inhibitors was investigated against an important fungal pathogen, Cryptococcus neoformans, revealing that they are also able to inhibit CA in microbial cells growing in vitro. At our best knowledge, this is the first report on newly designed synthetic compounds selectively targeting β-CAs and provides a proof of concept of microbial CAs suitability as an antimicrobial drug target.
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Affiliation(s)
| | - Laura Giovati
- b Department of Medicine and Surgery, Ospedale Maggiore di Parma , University of Parma , Parma , Italy
| | - Andrea Angeli
- c Department of NEUROFARBA, Section of Pharmaceutical and Nutraceutical Sciences , University of Florence , Firenze , Italy
| | - Marialaura Pavone
- a Department of Food and Drugs , University of Parma , Parma , Italy
| | - Sonia Del Prete
- c Department of NEUROFARBA, Section of Pharmaceutical and Nutraceutical Sciences , University of Florence , Firenze , Italy
| | - Marco Pieroni
- a Department of Food and Drugs , University of Parma , Parma , Italy
| | - Clemente Capasso
- d National Council of Research (CNR) , Istituto di Bioscenze e Biorisorse , Napoli , Italy
| | - Agostino Bruno
- a Department of Food and Drugs , University of Parma , Parma , Italy.,e Experimental Therapeutics Program , IFOM the FIRC Institute for Molecular Oncology Foundation , Milano , Italy
| | - Stefania Conti
- b Department of Medicine and Surgery, Ospedale Maggiore di Parma , University of Parma , Parma , Italy
| | - Walter Magliani
- b Department of Medicine and Surgery, Ospedale Maggiore di Parma , University of Parma , Parma , Italy
| | - Claudiu T Supuran
- c Department of NEUROFARBA, Section of Pharmaceutical and Nutraceutical Sciences , University of Florence , Firenze , Italy
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The contribution of the White Collar complex to Cryptococcus neoformans virulence is independent of its light-sensing capabilities. Fungal Genet Biol 2018; 121:56-64. [PMID: 30266690 DOI: 10.1016/j.fgb.2018.09.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 09/22/2018] [Accepted: 09/22/2018] [Indexed: 01/09/2023]
Abstract
The White Collar complex is responsible for sensing light and transmitting that signal in many fungal species. In Cryptococcus neoformans and C. deneoformans the complex is involved in protection against damage from ultraviolet (UV) light, repression of mating in response to light, and is also required for virulence. The mechanism by which the Bwc1 photoreceptor contributes to virulence is unknown. In this study, a bwc1 deletion mutant of C. neoformans was transformed with three versions of the BWC1 gene, the wild type, BWC1C605A or BWC1C605S, in which the latter two have the conserved cysteine residue replaced with either alanine or serine within the light-oxygen-voltage (LOV) domain that interacts with the flavin chromophore. The bwc1+ BWC1 strain complemented the UV sensitivity and the repression of mating in the light. The bwc1+ BWC1C605A and bwc1+ BWC1C605S strains were not fully complemented for either of the phenotypes, indicating that these BWC1 alleles impair the light responses for strains with them. Transcript analysis showed that neither of the mutated strains (bwc1+ BWC1C605A and bwc1+ BWC1C605S) showed the light-inducible expression pattern of the HEM15 and UVE1 genes as occurs in the wild type strain. These results indicate that the conserved flavin-binding site in the LOV domain of Bwc1 is required for sensing and responding to light in C. neoformans. In contrast to defects in light responses, the wild type, bwc1+ BWC1, bwc1+ BWC1C605A and bwc1+ BWC1C605S strains were equally virulent, whereas the bwc1 knock out mutant was less virulent. Furthermore, pre-exposure of the strains to light prior to inoculation had no influence on the outcome of infection. These findings define a division in function of the White Collar complex in fungi, in that in C. neoformans the role of Bwc1 in virulence is independent of light sensing.
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Wang LL, Lee KT, Jung KW, Lee DG, Bahn YS. The novel microtubule-associated CAP-glycine protein Cgp1 governs growth, differentiation, and virulence of Cryptococcus neoformans. Virulence 2018; 9:566-584. [PMID: 29338542 PMCID: PMC5955475 DOI: 10.1080/21505594.2017.1423189] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Microtubules are involved in mechanical support, cytoplasmic organization, and several cellular processes by interacting with diverse microtubule-associated proteins such as plus-end tracking proteins, motor proteins, and tubulin-folding cofactors. A number of the cytoskeleton-associated proteins (CAPs) contain the CAP-glycine-rich (CAP-Gly) domain, which is evolutionarily conserved and generally considered to bind to α-tubulin to regulate the function of microtubules. However, there has been a dearth of research on CAP-Gly proteins in fungal pathogens, including Cryptococcus neoformans, which is a global cause of fatal meningoencephalitis in immunocompromised patients. In this study, we identified five CAP-Gly protein-encoding genes in C. neoformans. Among these, Cgp1 encoded by CNAG_06352 has a unique domain structure containing CAP-Gly, SPEC, and Spc7 domains that is not orthologous to CAPs in other eukaryotes. Supporting the role of Cgp1 in microtubule-related function, we demonstrate that deletion or overexpression of CGP1 alters cellular susceptibility to thiabendazole, a microtubule destabilizer and that Cgp1 is co-localized with cytoplasmic microtubules. Related to the cellular function of microtubules, Cgp1 governs the maintenance of membrane stability and genotoxic stress responses. Deletion of CGP1 also reduces production of melanin pigment and attenuates the virulence of C. neoformans. Furthermore, we demonstrate that Cgp1 uniquely regulates the sexual differentiation of C. neoformans with distinct roles in the early and late stage of mating. Domain analysis revealed that the CAP-Gly domain plays a major role in all Cgp1 functions examined. In conclusion, this novel CAP-Gly protein, Cgp1, has pleotropic roles in regulating growth, stress responses, differentiation, and virulence in C. neoformans.
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Affiliation(s)
- Li Li Wang
- a Department of Biotechnology , College of Life Science and Biotechnology, Yonsei University , Seoul , Republic of Korea
| | - Kyung-Tae Lee
- a Department of Biotechnology , College of Life Science and Biotechnology, Yonsei University , Seoul , Republic of Korea
| | - Kwang-Woo Jung
- b Research Division for Biotechnology, Korea Atomic Energy Research Institute , Jeongeup , Republic of Korea
| | - Dong-Gi Lee
- a Department of Biotechnology , College of Life Science and Biotechnology, Yonsei University , Seoul , Republic of Korea
| | - Yong-Sun Bahn
- a Department of Biotechnology , College of Life Science and Biotechnology, Yonsei University , Seoul , Republic of Korea
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Motaung TE. Cryptococcus neoformans mutant screening: a genome-scale's worth of function discovery. FUNGAL BIOL REV 2018. [DOI: 10.1016/j.fbr.2018.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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35
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Wambaugh MA, Brown JCS. High-throughput Identification of Synergistic Drug Combinations by the Overlap2 Method. J Vis Exp 2018. [PMID: 29863672 DOI: 10.3791/57241] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Although antimicrobial drugs have dramatically increased the lifespan and quality of life in the 20th century, antimicrobial resistance threatens our entire society's ability to treat systemic infections. In the United States alone, antibiotic-resistant infections kill approximately 23,000 people a year and cost around 20 billion USD in additional healthcare. One approach to combat antimicrobial resistance is combination therapy, which is particularly useful in the critical early stage of infection, before the infecting organism and its drug resistance profile have been identified. Many antimicrobial treatments use combination therapies. However, most of these combinations are additive, meaning that the combined efficacy is the same as the sum of the individual antibiotic efficacy. Some combination therapies are synergistic: the combined efficacy is much greater than additive. Synergistic combinations are particularly useful because they can inhibit the growth of antimicrobial drug resistant strains. However, these combinations are rare and difficult to identify. This is due to the sheer number of molecules needed to be tested in a pairwise manner: a library of 1,000 molecules has 1 million potential combinations. Thus, efforts have been made to predict molecules for synergy. This article describes our high-throughput method for predicting synergistic small molecule pairs known as the Overlap2 Method (O2M). O2M uses patterns from chemical-genetic datasets to identify mutants that are hypersensitive to each molecule in a synergistic pair but not to other molecules. The Brown lab exploits this growth difference by performing a high-throughput screen for molecules that inhibit the growth of mutant but not wild-type cells. The lab's work previously identified molecules that synergize with the antibiotic trimethoprim and the antifungal drug fluconazole using this strategy. Here, the authors present a method to screen for novel synergistic combinations, which can be altered for multiple microorganisms.
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Affiliation(s)
- Morgan A Wambaugh
- Microbiology and Immunology Division, Department of Pathology, University of Utah
| | - Jessica C S Brown
- Microbiology and Immunology Division, Department of Pathology, University of Utah;
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Geddes-McAlister J, Shapiro RS. New pathogens, new tricks: emerging, drug-resistant fungal pathogens and future prospects for antifungal therapeutics. Ann N Y Acad Sci 2018; 1435:57-78. [DOI: 10.1111/nyas.13739] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 03/19/2018] [Accepted: 03/28/2018] [Indexed: 02/06/2023]
Affiliation(s)
- Jennifer Geddes-McAlister
- Department of Molecular and Cellular Biology; University of Guelph; Guelph Ontario Canada
- Department of Proteomics and Signal Transduction; Max Planck Institute of Biochemistry; Munich Germany
| | - Rebecca S. Shapiro
- Department of Molecular and Cellular Biology; University of Guelph; Guelph Ontario Canada
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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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Desjardins CA, Giamberardino C, Sykes SM, Yu CH, Tenor JL, Chen Y, Yang T, Jones AM, Sun S, Haverkamp MR, Heitman J, Litvintseva AP, Perfect JR, Cuomo CA. Population genomics and the evolution of virulence in the fungal pathogen Cryptococcus neoformans. Genome Res 2018; 27:1207-1219. [PMID: 28611159 PMCID: PMC5495072 DOI: 10.1101/gr.218727.116] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 05/01/2017] [Indexed: 12/23/2022]
Abstract
Cryptococcus neoformans is an opportunistic fungal pathogen that causes approximately 625,000 deaths per year from nervous system infections. Here, we leveraged a unique, genetically diverse population of C. neoformans from sub-Saharan Africa, commonly isolated from mopane trees, to determine how selective pressures in the environment coincidentally adapted C. neoformans for human virulence. Genome sequencing and phylogenetic analysis of 387 isolates, representing the global VNI and African VNB lineages, highlighted a deep, nonrecombining split in VNB (herein, VNBI and VNBII). VNBII was enriched for clinical samples relative to VNBI, while phenotypic profiling of 183 isolates demonstrated that VNBI isolates were significantly more resistant to oxidative stress and more heavily melanized than VNBII isolates. Lack of melanization in both lineages was associated with loss-of-function mutations in the BZP4 transcription factor. A genome-wide association study across all VNB isolates revealed sequence differences between clinical and environmental isolates in virulence factors and stress response genes. Inositol transporters and catabolism genes, which process sugars present in plants and the human nervous system, were identified as targets of selection in all three lineages. Further phylogenetic and population genomic analyses revealed extensive loss of genetic diversity in VNBI, suggestive of a history of population bottlenecks, along with unique evolutionary trajectories for mating type loci. These data highlight the complex evolutionary interplay between adaptation to natural environments and opportunistic infections, and that selection on specific pathways may predispose isolates to human virulence.
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Affiliation(s)
| | - Charles Giamberardino
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Sean M Sykes
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Chen-Hsin Yu
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Jennifer L Tenor
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Yuan Chen
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Timothy Yang
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Alexander M Jones
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Sheng Sun
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Miriam R Haverkamp
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Anastasia P Litvintseva
- Mycotic Diseases Branch, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30329, USA
| | - John R Perfect
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Christina A Cuomo
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
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Revie NM, Iyer KR, Robbins N, Cowen LE. Antifungal drug resistance: evolution, mechanisms and impact. Curr Opin Microbiol 2018; 45:70-76. [PMID: 29547801 DOI: 10.1016/j.mib.2018.02.005] [Citation(s) in RCA: 284] [Impact Index Per Article: 47.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 02/12/2018] [Indexed: 12/17/2022]
Abstract
Microorganisms have a remarkable capacity to evolve resistance to antimicrobial agents, threatening the efficacy of the limited arsenal of antimicrobials and becoming a dire public health crisis. This is of particular concern for fungal pathogens, which cause devastating invasive infections with treatment options limited to only three major classes of antifungal drugs. The paucity of antifungals with clinical utility is in part due to close evolutionary relationships between these eukaryotic pathogens and their human hosts, which limits the unique targets to be exploited therapeutically. This review highlights the mechanisms by which fungal pathogens of humans evolve resistance to antifungal drugs, which provide crucial insights to enable development of novel therapeutic strategies to thwart drug resistance and combat fungal infectious disease.
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Affiliation(s)
- Nicole M Revie
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5G 1M1, Canada
| | - Kali R Iyer
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5G 1M1, Canada
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5G 1M1, Canada
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5G 1M1, Canada.
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Regulated Release of Cryptococcal Polysaccharide Drives Virulence and Suppresses Immune Cell Infiltration into the Central Nervous System. Infect Immun 2018; 86:IAI.00662-17. [PMID: 29203547 PMCID: PMC5820953 DOI: 10.1128/iai.00662-17] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 11/29/2017] [Indexed: 12/22/2022] Open
Abstract
Cryptococcus neoformans is a common environmental yeast and opportunistic pathogen responsible for 15% of AIDS-related deaths worldwide. Mortality primarily results from meningoencephalitis, which occurs when fungal cells disseminate to the brain from the initial pulmonary infection site. A key C. neoformans virulence trait is the polysaccharide capsule. Capsule shields C. neoformans from immune-mediated recognition and destruction. The main capsule component, glucuronoxylomannan (GXM), is found both attached to the cell surface and free in the extracellular space (as exo-GXM). Exo-GXM accumulates in patient serum and cerebrospinal fluid at microgram/milliliter concentrations, has well-documented immunosuppressive properties, and correlates with poor patient outcomes. However, it is poorly understood whether exo-GXM release is regulated or the result of shedding during normal capsule turnover. We demonstrate that exo-GXM release is regulated by environmental cues and inversely correlates with surface capsule levels. We identified genes specifically involved in exo-GXM release that do not alter surface capsule thickness. The first mutant, the liv7Δ strain, released less GXM than wild-type cells when capsule was not induced. The second mutant, the cnag_00658Δ strain, released more exo-GXM under capsule-inducing conditions. Exo-GXM release observed in vitro correlated with polystyrene adherence, virulence, and fungal burden during murine infection. Additionally, we found that exo-GXM reduced cell size and capsule thickness under capsule-inducing conditions, potentially influencing dissemination. Finally, we demonstrated that exo-GXM prevents immune cell infiltration into the brain during disseminated infection and highly inflammatory intracranial infection. Our data suggest that exo-GXM performs a distinct role from capsule GXM during infection, altering cell size and suppressing inflammation.
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Enioutina EY, Teng L, Fateeva TV, Brown JCS, Job KM, Bortnikova VV, Krepkova LV, Gubarev MI, Sherwin CMT. Phytotherapy as an alternative to conventional antimicrobials: combating microbial resistance. Expert Rev Clin Pharmacol 2017; 10:1203-1214. [PMID: 28836870 DOI: 10.1080/17512433.2017.1371591] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
INTRODUCTION In the modern antimicrobial era, the rapid spread of resistance to antibiotics and introduction of new and mutating viruses is a global concern. Combating antimicrobial resistant microbes (AMR) requires coordinated international efforts that incorporate new conventional antibiotic development as well as development of alternative drugs with antimicrobial activity, management of existing antimicrobials, and rapid detection of AMR pathogens. Areas covered: This manuscript discusses some conventional strategies to control microbial resistance. The main purpose of the manuscript is to present information on specific herbal medicines that may serve as good treatment alternatives to conventional antimicrobials for infections sensitive to conventional as well as resistant strains of microorganisms. Expert commentary: Identification of potential new antimicrobials is challenging; however, one source for potential structurally diverse and complex antimicrobials are natural products. Natural products may have advantages over other post-germ theory antimicrobials. Many antimicrobial herbal medicines possess simultaneous antibacterial, antifungal, antiprotozoal and/or antiviral properties. Herbal products have the potential to boost host resistance to infections, particularly in immunocompromised patients. Antimicrobial broad-spectrum activity in conjunction with immunostimulatory properties may help to prevent microbial resistance to herbal medicine. As part of the efforts to broaden use of herbal medicines to treat microbial infections, pre-clinical and clinical testing guidelines of these compounds as a whole should be implemented to ensure consistency in formulation, efficacy and safety.
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Affiliation(s)
- Elena Yu Enioutina
- a Division of Clinical Pharmacology, the Department of Pediatrics, School of Medicine , University of Utah , Salt Lake City , UT , USA.,b Department of Pathology, School of Medicine , University of Utah , Salt Lake City , UT , USA
| | - Lida Teng
- c Department of Drug Policy & Management (DPM), Graduate School of Pharmaceutical Sciences , The University of Tokyo , Tokyo , Japan
| | - Tatyana V Fateeva
- d Center of Medicine , All-Russian Research Institute of Medicinal and Aromatic Plants (VILAR) , Moscow , Russia
| | - Jessica C S Brown
- b Department of Pathology, School of Medicine , University of Utah , Salt Lake City , UT , USA
| | - Kathleen M Job
- a Division of Clinical Pharmacology, the Department of Pediatrics, School of Medicine , University of Utah , Salt Lake City , UT , USA
| | - Valentina V Bortnikova
- d Center of Medicine , All-Russian Research Institute of Medicinal and Aromatic Plants (VILAR) , Moscow , Russia
| | - Lubov V Krepkova
- d Center of Medicine , All-Russian Research Institute of Medicinal and Aromatic Plants (VILAR) , Moscow , Russia
| | | | - Catherine M T Sherwin
- a Division of Clinical Pharmacology, the Department of Pediatrics, School of Medicine , University of Utah , Salt Lake City , UT , USA.,f Department of Pharmacology and Toxicology , University of Utah , Salt Lake City , UT , USA
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Abstract
Chemical-genetic approaches are based on measuring the cellular outcome of combining genetic and chemical perturbations in large-numbers in tandem. In these approaches the contribution of every gene to the fitness of an organism is measured upon exposure to different chemicals. Current technological advances enable the application of chemical genetics to almost any organism and at an unprecedented throughput. Here we review the underlying concepts behind chemical genetics, present its different vignettes and illustrate how such approaches can propel drug discovery.
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Affiliation(s)
- Elisabetta Cacace
- European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg, Germany
| | - George Kritikos
- European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg, Germany
| | - Athanasios Typas
- European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg, Germany
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Korem M, Kagan S, Polacheck I. The Effect of Novel Heterocyclic Compounds on Cryptococcal Biofilm. J Fungi (Basel) 2017; 3:E42. [PMID: 29371559 PMCID: PMC5715956 DOI: 10.3390/jof3030042] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 07/13/2017] [Accepted: 07/17/2017] [Indexed: 02/04/2023] Open
Abstract
Biofilm formation by microorganisms depends on their communication by quorum sensing, which is mediated by small diffusible signaling molecules that accumulate in the extracellular environment. During human infection, the pathogenic yeast Cryptococcus neoformans can form biofilm on medical devices, which protects the organism and increases its resistance to antifungal agents. The aim of this study was to test two novel heterocyclic compounds, S-8 (thiazolidinedione derivative, TZD) and NA-8 (succinimide derivative, SI), for their anti-biofilm activity against strains of Cryptococcus neoformans and Cryptococcus gattii. Biofilms were formed in a defined medium in 96-well polystyrene plates and 8-well micro-slides. The effect of sub-inhibitory concentrations of S-8 and NA-8 on biofilm formation was measured after 48 h by a metabolic reduction assay and by confocal laser microscopy analysis using fluorescent staining. The formation and development of cryptococcal biofilms was inhibited significantly by these compounds in concentrations below the minimum inhibitory concentration (MIC) values. These compounds may have a potential role in preventing fungal biofilm development on indwelling medical devices or even as a therapeutic measure after the establishment of biofilm.
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Affiliation(s)
- Maya Korem
- Department of Clinical Microbiology and Infectious Diseases, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel.
| | - Sarah Kagan
- Department of Clinical Microbiology and Infectious Diseases, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel.
| | - Itzhack Polacheck
- Department of Clinical Microbiology and Infectious Diseases, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel.
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Wambaugh MA, Shakya VPS, Lewis AJ, Mulvey MA, Brown JCS. High-throughput identification and rational design of synergistic small-molecule pairs for combating and bypassing antibiotic resistance. PLoS Biol 2017; 15:e2001644. [PMID: 28632788 PMCID: PMC5478098 DOI: 10.1371/journal.pbio.2001644] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 05/17/2017] [Indexed: 02/06/2023] Open
Abstract
Antibiotic-resistant infections kill approximately 23,000 people and cost $20,000,000,000 each year in the United States alone despite the widespread use of small-molecule antimicrobial combination therapy. Antibiotic combinations typically have an additive effect: the efficacy of the combination matches the sum of the efficacies of each antibiotic when used alone. Small molecules can also act synergistically when the efficacy of the combination is greater than the additive efficacy. However, synergistic combinations are rare and have been historically difficult to identify. High-throughput identification of synergistic pairs is limited by the scale of potential combinations: a modest collection of 1,000 small molecules involves 1 million pairwise combinations. Here, we describe a high-throughput method for rapid identification of synergistic small-molecule pairs, the overlap2 method (O2M). O2M extracts patterns from chemical-genetic datasets, which are created when a collection of mutants is grown in the presence of hundreds of different small molecules, producing a precise set of phenotypes induced by each small molecule across the mutant set. The identification of mutants that show the same phenotype when treated with known synergistic molecules allows us to pinpoint additional molecule combinations that also act synergistically. As a proof of concept, we focus on combinations with the antibiotics trimethoprim and sulfamethizole, which had been standard treatment against urinary tract infections until widespread resistance decreased efficacy. Using O2M, we screened a library of 2,000 small molecules and identified several that synergize with the antibiotic trimethoprim and/or sulfamethizole. The most potent of these synergistic interactions is with the antiviral drug azidothymidine (AZT). We then demonstrate that understanding the molecular mechanism underlying small-molecule synergistic interactions allows the rational design of additional combinations that bypass drug resistance. Trimethoprim and sulfamethizole are both folate biosynthesis inhibitors. We find that this activity disrupts nucleotide homeostasis, which blocks DNA replication in the presence of AZT. Building on these data, we show that other small molecules that disrupt nucleotide homeostasis through other mechanisms (hydroxyurea and floxuridine) also act synergistically with AZT. These novel combinations inhibit the growth and virulence of trimethoprim-resistant clinical Escherichia coli and Klebsiella pneumoniae isolates, suggesting that they may be able to be rapidly advanced into clinical use. In sum, we present a generalizable method to screen for novel synergistic combinations, to identify particular mechanisms resulting in synergy, and to use the mechanistic knowledge to rationally design new combinations that bypass drug resistance.
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MESH Headings
- Animals
- Anti-Bacterial Agents/chemistry
- Anti-Bacterial Agents/pharmacology
- Anti-Bacterial Agents/therapeutic use
- Anti-Infective Agents, Urinary/chemistry
- Anti-Infective Agents, Urinary/pharmacology
- Anti-Infective Agents, Urinary/therapeutic use
- Bacterial Proteins/antagonists & inhibitors
- Bacterial Proteins/genetics
- Bacterial Proteins/metabolism
- Biological Assay
- Computational Biology
- Drug Design
- Drug Resistance, Multiple, Bacterial
- Drug Synergism
- Drug Therapy, Combination
- Embryo, Nonmammalian/drug effects
- Embryo, Nonmammalian/metabolism
- Embryo, Nonmammalian/microbiology
- Escherichia coli/drug effects
- Escherichia coli/growth & development
- Escherichia coli/metabolism
- Escherichia coli Infections/drug therapy
- Escherichia coli Infections/metabolism
- Escherichia coli Infections/microbiology
- Folic Acid Antagonists/chemistry
- Folic Acid Antagonists/pharmacology
- Folic Acid Antagonists/therapeutic use
- High-Throughput Screening Assays
- Klebsiella Infections/drug therapy
- Klebsiella Infections/metabolism
- Klebsiella Infections/microbiology
- Klebsiella pneumoniae/drug effects
- Klebsiella pneumoniae/growth & development
- Klebsiella pneumoniae/metabolism
- Microbial Sensitivity Tests
- Mutation
- Mutation Rate
- Pattern Recognition, Automated
- Reverse Transcriptase Inhibitors/chemistry
- Reverse Transcriptase Inhibitors/pharmacology
- Reverse Transcriptase Inhibitors/therapeutic use
- Small Molecule Libraries
- Sulfamethizole/agonists
- Sulfamethizole/chemistry
- Sulfamethizole/pharmacology
- Sulfamethizole/therapeutic use
- Trimethoprim/agonists
- Trimethoprim/chemistry
- Trimethoprim/pharmacology
- Trimethoprim/therapeutic use
- Zebrafish/embryology
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Affiliation(s)
- Morgan A. Wambaugh
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Viplendra P. S. Shakya
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Adam J. Lewis
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Matthew A. Mulvey
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Jessica C. S. Brown
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
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A tool named Iris for versatile high-throughput phenotyping in microorganisms. Nat Microbiol 2017; 2:17014. [PMID: 28211844 PMCID: PMC5464397 DOI: 10.1038/nmicrobiol.2017.14] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 01/10/2017] [Indexed: 12/14/2022]
Abstract
Advances in our ability to systematically introduce and track controlled genetic variance in microbes have fueled high-throughput reverse genetics approaches in the past decade. When coupled to quantitative readouts, such approaches are extremely powerful at elucidating gene function and providing insights into the underlying pathways and the overall cellular network organization. Yet, until now all efforts for quantifying microbial macroscopic phenotypes have been restricted to monitoring growth in a small number of model microbes. We developed an image analysis software named Iris, which allows for systematic exploration of a number of orthogonal-to-growth processes, including biofilm formation, colony morphogenesis, envelope biogenesis, sporulation and reporter activity. In addition, Iris provides more sensitive growth measurements than current available software, and is compatible with a variety of different microbes, as well as with endpoint or kinetic data. We used Iris to reanalyze existing chemical genomics data in Escherichia coli and to perform proof-of-principle screens on colony biofilm formation and morphogenesis of different bacterial species and the pathogenic fungus, Candida albicans. Thereby we recapitulated existing knowledge but also identified a plethora of additional genes and pathways involved in both processes.
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Abstract
ABSTRACT
Invasive fungal infections are becoming an increasingly important cause of human mortality and morbidity, particularly for immunocompromised populations. The fungal pathogens
Candida albicans
,
Cryptococcus neoformans
, and
Aspergillus fumigatus
collectively contribute to over 1 million human deaths annually. Hence, the importance of safe and effective antifungal therapeutics for the practice of modern medicine has never been greater. Given that fungi are eukaryotes like their human host, the number of unique molecular targets that can be exploited for drug development remains limited. Only three classes of molecules are currently approved for the treatment of invasive mycoses. The efficacy of these agents is compromised by host toxicity, fungistatic activity, or the emergence of drug resistance in pathogen populations. Here we describe our current arsenal of antifungals and highlight current strategies that are being employed to improve the therapeutic safety and efficacy of these drugs. We discuss state-of-the-art approaches to discover novel chemical matter with antifungal activity and highlight some of the most promising new targets for antifungal drug development. We feature the benefits of combination therapy as a strategy to expand our current repertoire of antifungals and discuss the antifungal combinations that have shown the greatest potential for clinical development. Despite the paucity of new classes of antifungals that have come to market in recent years, it is clear that by leveraging innovative approaches to drug discovery and cultivating collaborations between academia and industry, there is great potential to bolster the antifungal armamentarium.
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Pianalto KM, Alspaugh JA. New Horizons in Antifungal Therapy. J Fungi (Basel) 2016; 2:jof2040026. [PMID: 29376943 PMCID: PMC5715934 DOI: 10.3390/jof2040026] [Citation(s) in RCA: 100] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 09/19/2016] [Accepted: 09/20/2016] [Indexed: 12/20/2022] Open
Abstract
Recent investigations have yielded both profound insights into the mechanisms required by pathogenic fungi for virulence within the human host, as well as novel potential targets for antifungal therapeutics. Some of these studies have resulted in the identification of novel compounds that act against these pathways and also demonstrate potent antifungal activity. However, considerable effort is required to move from pre-clinical compound testing to true clinical trials, a necessary step toward ultimately bringing new drugs to market. The rising incidence of invasive fungal infections mandates continued efforts to identify new strategies for antifungal therapy. Moreover, these life-threatening infections often occur in our most vulnerable patient populations. In addition to finding completely novel antifungal compounds, there is also a renewed effort to redirect existing drugs for use as antifungal agents. Several recent screens have identified potent antifungal activity in compounds previously indicated for other uses in humans. Together, the combined efforts of academic investigators and the pharmaceutical industry is resulting in exciting new possibilities for the treatment of invasive fungal infections.
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Affiliation(s)
- Kaila M Pianalto
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA.
| | - J Andrew Alspaugh
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA.
- Department of Medicine/Infectious Diseases, Duke University School of Medicine, Durham, NC 27710, USA.
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50
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Ding H, Mayer FL, Sánchez-León E, de S Araújo GR, Frases S, Kronstad JW. Networks of fibers and factors: regulation of capsule formation in Cryptococcus neoformans. F1000Res 2016; 5. [PMID: 27516877 PMCID: PMC4979528 DOI: 10.12688/f1000research.8854.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/12/2016] [Indexed: 12/15/2022] Open
Abstract
The ability of the pathogenic fungus
Cryptococcus neoformans to cause life-threatening meningoencephalitis in immunocompromised individuals is due in large part to elaboration of a capsule consisting of polysaccharide fibers. The size of the cell-associated capsule is remarkably responsive to a variety of environmental and host conditions, but the mechanistic details of the regulation, synthesis, trafficking, and attachment of the polysaccharides are poorly understood. Recent studies reveal a complex network of transcription factors that influence capsule elaboration in response to several different signals of relevance to disease (e.g., iron deprivation). The emerging complexity of the network is consistent with the diversity of conditions that influence the capsule and illustrates the responsiveness of the fungus to both the environment and mammalian hosts.
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Affiliation(s)
- Hao Ding
- Michael Smith Laboratories, University of British Columbia, Vancouver, Canada
| | - François L Mayer
- Michael Smith Laboratories, University of British Columbia, Vancouver, Canada
| | - Eddy Sánchez-León
- Michael Smith Laboratories, University of British Columbia, Vancouver, Canada
| | - Glauber R de S Araújo
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Susana Frases
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - James W Kronstad
- Michael Smith Laboratories, University of British Columbia, Vancouver, Canada.,Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
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