1
|
Prusty JS, Kumar A, Kumar A. Anti-fungal peptides: an emerging category with enthralling therapeutic prospects in the treatment of candidiasis. Crit Rev Microbiol 2024:1-37. [PMID: 39440616 DOI: 10.1080/1040841x.2024.2418125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Revised: 10/10/2024] [Accepted: 10/13/2024] [Indexed: 10/25/2024]
Abstract
Candida infections, particularly invasive candidiasis, pose a serious global health threat. Candida albicans is the most prevalent species causing candidiasis, and resistance to key antifungal drugs, such as azoles, echinocandins, polyenes, and fluoropyrimidines, has emerged. This growing multidrug resistance (MDR) complicates treatment options, highlighting the need for novel therapeutic approaches. Antifungal peptides (AFPs) are gaining recognition for their potential as new antifungal agents due to their diverse structures and functions. These natural or recombinant peptides can effectively target fungal virulence and viability, making them promising candidates for future antifungal development. This review examines infections caused by Candida species, the limitations of current antifungal treatments, and the therapeutic potential of AFPs. It emphasizes the importance of identifying novel AFP targets and their production for advancing treatment strategies. By discussing the therapeutic development of AFPs, the review aims to draw researchers' attention to this promising field. The integration of knowledge about AFPs could pave the way for novel antifungal agents with broad-spectrum activity, reduced toxicity, targeted action, and mechanisms that limit resistance in pathogenic fungi, offering significant advancements in antifungal therapeutics.
Collapse
Affiliation(s)
- Jyoti Sankar Prusty
- Department of Biotechnology, National Institute of Technology Raipur, Raipur, India
| | - Ashwini Kumar
- Department of Life Sciences, School of Basic Sciences and Research, Sharda University, Greater Noida, India
| | - Awanish Kumar
- Department of Biotechnology, National Institute of Technology Raipur, Raipur, India
| |
Collapse
|
2
|
Weerasinghe H, Stölting H, Rose AJ, Traven A. Metabolic homeostasis in fungal infections from the perspective of pathogens, immune cells, and whole-body systems. Microbiol Mol Biol Rev 2024; 88:e0017122. [PMID: 39230301 PMCID: PMC11426019 DOI: 10.1128/mmbr.00171-22] [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: 09/05/2024] Open
Abstract
SUMMARYThe ability to overcome metabolic stress is a major determinant of outcomes during infections. Pathogens face nutrient and oxygen deprivation in host niches and during their encounter with immune cells. Immune cells require metabolic adaptations for producing antimicrobial compounds and mounting antifungal inflammation. Infection also triggers systemic changes in organ metabolism and energy expenditure that range from an enhanced metabolism to produce energy for a robust immune response to reduced metabolism as infection progresses, which coincides with immune and organ dysfunction. Competition for energy and nutrients between hosts and pathogens means that successful survival and recovery from an infection require a balance between elimination of the pathogen by the immune systems (resistance), and doing so with minimal damage to host tissues and organs (tolerance). Here, we discuss our current knowledge of pathogen, immune cell and systemic metabolism in fungal infections, and the impact of metabolic disorders, such as obesity and diabetes. We put forward the idea that, while our knowledge of the use of metabolic regulation for fungal proliferation and antifungal immune responses (i.e., resistance) has been growing over the years, we also need to study the metabolic mechanisms that control tolerance of fungal pathogens. A comprehensive understanding of how to balance resistance and tolerance by metabolic interventions may provide insights into therapeutic strategies that could be used adjunctly with antifungal drugs to improve patient outcomes.
Collapse
Affiliation(s)
- Harshini Weerasinghe
- Department of Biochemistry and Molecular Biology and the Infection Program, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Centre to Impact AMR, Monash University, Clayton, Victoria, Australia
| | - Helen Stölting
- Department of Biochemistry and Molecular Biology and the Metabolism, Diabetes and Obesity Program, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Adam J Rose
- Department of Biochemistry and Molecular Biology and the Metabolism, Diabetes and Obesity Program, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Ana Traven
- Department of Biochemistry and Molecular Biology and the Infection Program, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Centre to Impact AMR, Monash University, Clayton, Victoria, Australia
| |
Collapse
|
3
|
Kumaravel N, Ebinezer LB, Ashwin NMR, Franchin C, Battisti I, Carletti P, Ramesh Sundar A, Masi A, Malathi P, Viswanathan R, Arrigoni G. Comparative proteomics of sugarcane smut fungus - Sporisorium scitamineum unravels dynamic proteomic alterations during the dimorphic transition. J Proteomics 2024; 304:105230. [PMID: 38901800 DOI: 10.1016/j.jprot.2024.105230] [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: 12/11/2023] [Revised: 06/07/2024] [Accepted: 06/16/2024] [Indexed: 06/22/2024]
Abstract
Life cycle of the dimorphic sugarcane smut fungi, Sporisorium scitamineum, involves recognition and mating of compatible saprophytic yeast-like haploid sporidia (MAT-1 and MAT-2) that upon fusion, develop into infective dikaryotic mycelia. Although the dimorphic transition is intrinsically linked with the pathogenicity and virulence of S. scitamineum, it has never been studied using a proteomic approach. In the present study, an iTRAQ-based comparative proteomic analysis of three distinct stages was carried out. The stages were: the dimorphic transition period - haploid sporidial stage (MAT-1 and MAT-2); the transition phase (24 h post co-culturing (hpc)) and the dikaryotic mycelial stage (48 hpc). Functional categorization of differentially abundant proteins showed that the most altered biological processes were energy production, primary metabolism, especially, carbohydrate, amino acid, fatty acid, followed by translation, post-translation and protein turnover. Several differentially abundant proteins (DAPs), especially in the dikaryotic mycelial stage were predicted as effectors. Taken together, key molecular mechanisms underpinning the dimorphic transition in S. scitamineum at the proteome level were highlighted. The catalogue of stage-specific and dimorphic transition-associated-proteins and potential effectors identified herein represents a list of potential candidates for defective mutant screening to elucidate their functional role in the dimorphic transition and pathogenicity in S. scitamineum. BIOLOGICAL SIGNIFICANCE: Being the first comparative proteomics analysis of S. scitamineum, this study comprehensively examined three pivotal life cycle stages of the pathogen: the non-pathogenic haploid phase, the transition phase, and the pathogenic dikaryotic mycelial stage. While previous studies have reported the sugarcane and S. scitamineum interactions, this study endeavored to specifically identify the proteins responsible for pathogenicity. By analyzing the proteomic alterations between the haploid and dikaryotic mycelial phases, the study revealed significant changes in metabolic pathway-associated proteins linked to energy production, notably oxidative phosphorylation, and the citrate cycle. Furthermore, this study successfully identified key metabolic pathways that undergo reprogramming during the transition from the non-pathogenic to the pathogenic stage. The study also deciphered the underlying mechanisms driving the morphological and physiological alterations crucial for the S. scitamineum virulence. By studying its life cycle stages, identifying the key metabolic pathways and stage-specific proteins, it provides unprecedented insights into the pathogenicity and potential avenues for intervention. As proteomics continues to advance, such studies pave the way for a deeper understanding of plant-pathogen interactions and the development of innovative strategies to mitigate the impact of devastating pathogens like S. scitamineum.
Collapse
Affiliation(s)
- Nalayeni Kumaravel
- Division of Crop Protection, Indian Council of Agricultural Research - Sugarcane Breeding Institute, Coimbatore 641007, Tamil Nadu, India.
| | - Leonard Barnabas Ebinezer
- Department of Agronomy, Food, Natural Resources, Animals, and Environment, University of Padova, viale dell'Università, 16, 35020 Padova, Italy.
| | - N M R Ashwin
- Division of Crop Protection, Indian Council of Agricultural Research - Sugarcane Breeding Institute, Coimbatore 641007, Tamil Nadu, India; Biochemical Sciences Division, Council of Scientific and Industrial Research - National Chemical Laboratory, Pune 411008, Maharashtra, India.
| | - Cinzia Franchin
- Proteomics Center, University of Padova and Azienda Ospedaliera di Padova, via G. Orus 2/B, 35129 Padova, Italy; Department of Biomedical Sciences, University of Padova, via U. Bassi 58/B, 35131 Padova, Italy.
| | - Ilaria Battisti
- Department of Agronomy, Food, Natural Resources, Animals, and Environment, University of Padova, viale dell'Università, 16, 35020 Padova, Italy.
| | - Paolo Carletti
- Department of Agronomy, Food, Natural Resources, Animals, and Environment, University of Padova, viale dell'Università, 16, 35020 Padova, Italy.
| | - Amalraj Ramesh Sundar
- Division of Crop Protection, Indian Council of Agricultural Research - Sugarcane Breeding Institute, Coimbatore 641007, Tamil Nadu, India.
| | - Antonio Masi
- Department of Agronomy, Food, Natural Resources, Animals, and Environment, University of Padova, viale dell'Università, 16, 35020 Padova, Italy.
| | - Palaniyandi Malathi
- Division of Crop Protection, Indian Council of Agricultural Research - Sugarcane Breeding Institute, Coimbatore 641007, Tamil Nadu, India.
| | - Rasappa Viswanathan
- Division of Crop Protection, Indian Council of Agricultural Research - Sugarcane Breeding Institute, Coimbatore 641007, Tamil Nadu, India; Indian Council of Agricultural Research - Indian Institute of Sugarcane Research, Lucknow, Uttar Pradesh 226002, India.
| | - Giorgio Arrigoni
- Proteomics Center, University of Padova and Azienda Ospedaliera di Padova, via G. Orus 2/B, 35129 Padova, Italy; Department of Biomedical Sciences, University of Padova, via U. Bassi 58/B, 35131 Padova, Italy.
| |
Collapse
|
4
|
Ewald J, He Z, Dimitriew W, Schuster S. Including glutamine in a resource allocation model of energy metabolism in cancer and yeast cells. NPJ Syst Biol Appl 2024; 10:77. [PMID: 39025861 PMCID: PMC11258256 DOI: 10.1038/s41540-024-00393-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 06/10/2024] [Indexed: 07/20/2024] Open
Abstract
Energy metabolism is crucial for all living cells, especially during fast growth or stress scenarios. Many cancer and activated immune cells (Warburg effect) or yeasts (Crabtree effect) mostly rely on aerobic glucose fermentation leading to lactate or ethanol, respectively, to generate ATP. In recent years, several mathematical models have been proposed to explain the Warburg effect on theoretical grounds. Besides glucose, glutamine is a very important substrate for eukaryotic cells-not only for biosynthesis, but also for energy metabolism. Here, we present a minimal constraint-based stoichiometric model for explaining both the classical Warburg effect and the experimentally observed respirofermentation of glutamine (WarburQ effect). We consider glucose and glutamine respiration as well as the respective fermentation pathways. Our resource allocation model calculates the ATP production rate, taking into account enzyme masses and, therefore, pathway costs. While our calculation predicts glucose fermentation to be a superior energy-generating pathway in human cells, different enzyme characteristics in yeasts reduce this advantage, in some cases to such an extent that glucose respiration is preferred. The latter is observed for the fungal pathogen Candida albicans, which is a known Crabtree-negative yeast. Further, optimization results show that glutamine is a valuable energy source and important substrate under glucose limitation, in addition to its role as a carbon and nitrogen source of biomass in eukaryotic cells. In conclusion, our model provides insights that glutamine is an underestimated fuel for eukaryotic cells during fast growth and infection scenarios and explains well the observed parallel respirofermentation of glucose and glutamine in several cell types.
Collapse
Affiliation(s)
- Jan Ewald
- Department of Bioinformatics, Friedrich Schiller University of Jena, Ernst-Abbe-Platz 2, 07743, Jena, Germany
- Center for Scalable Data Analytics and Artificial Intelligence (ScaDS.AI) Dresden/Leipzig, Leipzig University, Humboldtstraße 25, 04105, Leipzig, Germany
| | - Ziyang He
- Department of Bioinformatics, Friedrich Schiller University of Jena, Ernst-Abbe-Platz 2, 07743, Jena, Germany
| | - Wassili Dimitriew
- Department of Bioinformatics, Friedrich Schiller University of Jena, Ernst-Abbe-Platz 2, 07743, Jena, Germany
| | - Stefan Schuster
- Department of Bioinformatics, Friedrich Schiller University of Jena, Ernst-Abbe-Platz 2, 07743, Jena, Germany.
| |
Collapse
|
5
|
Wu Y, Sun A, Chen F, Zhao Y, Zhu X, Zhang T, Ni G, Wang R. Synthesis, structure-activity relationship and biological evaluation of indole derivatives as anti-Candida albicans agents. Bioorg Chem 2024; 146:107293. [PMID: 38507998 DOI: 10.1016/j.bioorg.2024.107293] [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: 11/30/2023] [Revised: 02/29/2024] [Accepted: 03/15/2024] [Indexed: 03/22/2024]
Abstract
In this work, we synthesized a series of indole derivatives to cope with the current increasing fungal infections caused by drug-resistant Candida albicans. All compounds were evaluated for antifungal activities against Candida albicans in vitro, and the structure-activity relationships (SARs) were analyzed. The results indicated that indole derivatives used either alone or in combination with fluconazole showed good activities against fluconazole-resistant Candida albicans. Further mechanisms studies demonstrated that compound 1 could inhibit yeast-to-hypha transition and biofilm formation of Candida albicans, increase the activity of the efflux pump, the damage of mitochondrial function, and the decrease of intracellular ATP content. In vivo studies, further proved the anti-Candida albicans activity of compound 1 by histological observation. Therefore, compound 1 could be considered as a novel antifungal agent.
Collapse
Affiliation(s)
- Yandan Wu
- School of Chinese Materia Medica, Yunnan University of Chinese Medicine, Kunming 650500, Yunnan Province, China
| | - Aimei Sun
- School of Chinese Materia Medica, Yunnan University of Chinese Medicine, Kunming 650500, Yunnan Province, China
| | - Fei Chen
- School of Chinese Materia Medica, Yunnan University of Chinese Medicine, Kunming 650500, Yunnan Province, China
| | - Yin Zhao
- School of Chinese Materia Medica, Yunnan University of Chinese Medicine, Kunming 650500, Yunnan Province, China
| | - Xianhu Zhu
- School of Chinese Materia Medica, Yunnan University of Chinese Medicine, Kunming 650500, Yunnan Province, China
| | - Tianbao Zhang
- School of Chinese Materia Medica, Yunnan University of Chinese Medicine, Kunming 650500, Yunnan Province, China
| | - Guanghui Ni
- School of Chinese Materia Medica, Yunnan University of Chinese Medicine, Kunming 650500, Yunnan Province, China.
| | - Ruirui Wang
- School of Chinese Materia Medica, Yunnan University of Chinese Medicine, Kunming 650500, Yunnan Province, China.
| |
Collapse
|
6
|
Edrich ESM, Duvenage L, Gourlay CW. Alternative Oxidase - Aid or obstacle to combat the rise of fungal pathogens? BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2024; 1865:149031. [PMID: 38195037 DOI: 10.1016/j.bbabio.2024.149031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 11/16/2023] [Accepted: 01/03/2024] [Indexed: 01/11/2024]
Abstract
Fungal pathogens present a growing threat to both humans and global health security alike. Increasing evidence of antifungal resistance in fungal populations that infect both humans and plant species has increased reliance on combination therapies and shown the need for new antifungal therapeutic targets to be investigated. Here, we review the roles of mitochondria and fungal respiration in pathogenesis and discuss the role of the Alternative Oxidase enzyme (Aox) in both human fungal pathogens and phytopathogens. Increasing evidence exists for Aox within mechanisms that underpin fungal virulence. Aox also plays important roles in adaptability that may prove useful within dual targeted fungal-specific therapeutic approaches. As improved fungal specific mitochondrial and Aox inhibitors are under development we may see this as an emerging target for future approaches to tackling the growing challenge of fungal infection.
Collapse
Affiliation(s)
| | - Lucian Duvenage
- CMM AFRICA Medical Mycology Research Unit, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Campbell W Gourlay
- Kent Fungal Group, School of Biosciences, University of Kent, Kent CT2 9HY, UK.
| |
Collapse
|
7
|
Zeng G, Xu X, Kok YJ, Deng FS, Ling Chow EW, Gao J, Bi X, Wang Y. Cytochrome c regulates hyphal morphogenesis by interfering with cAMP-PKA signaling in Candida albicans. Cell Rep 2023; 42:113473. [PMID: 37980562 DOI: 10.1016/j.celrep.2023.113473] [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: 06/19/2023] [Revised: 10/17/2023] [Accepted: 11/06/2023] [Indexed: 11/21/2023] Open
Abstract
In the human fungal pathogen Candida albicans, invasive hyphal growth is a well-recognized virulence trait. We employed transposon-mediated genome-wide mutagenesis, revealing that inactivating CTM1 blocks hyphal growth. CTM1 encodes a lysine (K) methyltransferase, which trimethylates cytochrome c (Cyc1) at K79. Mutants lacking CTM1 or expressing cyc1K79A grow as yeast under hyphae-inducing conditions, indicating that unmethylated Cyc1 suppresses hyphal growth. Transcriptomic analyses detected increased levels of the hyphal repressor NRG1 and decreased levels of hyphae-specific genes in ctm1Δ/Δ and cyc1K79A mutants, suggesting cyclic AMP (cAMP)-protein kinase A (PKA) signaling suppression. Co-immunoprecipitation and in vitro kinase assays demonstrated that unmethylated Cyc1 inhibits PKA kinase activity. Surprisingly, hyphae-defective ctm1Δ/Δ and cyc1K79A mutants remain virulent in mice due to accelerated proliferation. Our results unveil a critical role for cytochrome c in maintaining the virulence of C. albicans by orchestrating proliferation, growth mode, and metabolism. Importantly, this study identifies a biological function for lysine methylation on cytochrome c.
Collapse
Affiliation(s)
- Guisheng Zeng
- A(∗)STAR Infectious Diseases Labs (A(∗)STAR ID Labs), Agency for Science, Technology and Research (A(∗)STAR), 8A Biomedical Grove, #05-13 Immunos, Singapore 138648, Singapore.
| | - Xiaoli Xu
- A(∗)STAR Infectious Diseases Labs (A(∗)STAR ID Labs), Agency for Science, Technology and Research (A(∗)STAR), 8A Biomedical Grove, #05-13 Immunos, Singapore 138648, Singapore
| | - Yee Jiun Kok
- Bioprocessing Technology Institute, 20 Biopolis Way, #06-01 Centros, Singapore 138668, Singapore
| | - Fu-Sheng Deng
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, Taipei 10617, Taiwan
| | - Eve Wai Ling Chow
- A(∗)STAR Infectious Diseases Labs (A(∗)STAR ID Labs), Agency for Science, Technology and Research (A(∗)STAR), 8A Biomedical Grove, #05-13 Immunos, Singapore 138648, Singapore
| | - Jiaxin Gao
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xuezhi Bi
- Bioprocessing Technology Institute, 20 Biopolis Way, #06-01 Centros, Singapore 138668, Singapore; Duke-NUS Medical School, National University of Singapore, Singapore 169857, Singapore
| | - Yue Wang
- A(∗)STAR Infectious Diseases Labs (A(∗)STAR ID Labs), Agency for Science, Technology and Research (A(∗)STAR), 8A Biomedical Grove, #05-13 Immunos, Singapore 138648, Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore.
| |
Collapse
|
8
|
Case NT, Westman J, Hallett MT, Plumb J, Farheen A, Maxson ME, MacAlpine J, Liston SD, Hube B, Robbins N, Whitesell L, Grinstein S, Cowen LE. Respiration supports intraphagosomal filamentation and escape of Candida albicans from macrophages. mBio 2023; 14:e0274523. [PMID: 38038475 PMCID: PMC10746240 DOI: 10.1128/mbio.02745-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Accepted: 10/16/2023] [Indexed: 12/02/2023] Open
Abstract
IMPORTANCE Candida albicans is a leading human fungal pathogen that often causes life-threatening infections in immunocompromised individuals. The ability of C. albicans to transition between yeast and filamentous forms is key to its virulence, and this occurs in response to many host-relevant cues, including engulfment by host macrophages. While previous efforts identified C. albicans genes required for filamentation in other conditions, the genes important for this morphological transition upon internalization by macrophages remained largely enigmatic. Here, we employed a functional genomic approach to identify genes that enable C. albicans filamentation within macrophages and uncovered a role for the mitochondrial ribosome, respiration, and the SNF1 AMP-activated kinase complex. Additionally, we showed that glucose uptake and glycolysis by macrophages support C. albicans filamentation. This work provides insights into the metabolic dueling that occurs during the interaction of C. albicans with macrophages and identifies vulnerabilities in C. albicans that could serve as promising therapeutic targets.
Collapse
Affiliation(s)
- Nicola T. Case
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Johannes Westman
- Program in Cell Biology, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
| | | | - Jonathan Plumb
- Program in Cell Biology, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Aiman Farheen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Michelle E. Maxson
- Program in Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Jessie MacAlpine
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Sean D. Liston
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany
- Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Luke Whitesell
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Sergio Grinstein
- Program in Cell Biology, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
- Keenan Research Center of the Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, Ontario, Canada
| | - Leah E. Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| |
Collapse
|
9
|
Sharma R, Gibb AA, Barnts K, Elrod JW, Puri S. Alternative oxidase promotes high iron tolerance in Candida albicans. Microbiol Spectr 2023; 11:e0215723. [PMID: 37929974 PMCID: PMC10714975 DOI: 10.1128/spectrum.02157-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 10/10/2023] [Indexed: 11/07/2023] Open
Abstract
IMPORTANCE The yeast C. albicans exhibits metabolic flexibility for adaptability to host niches with varying availability of nutrients including essential metals like iron. For example, blood is iron deplete, while the oral cavity and the intestinal lumen are considered iron replete. We show here that C. albicans can tolerate very high levels of environmental iron, despite an increase in high iron-induced reactive oxygen species (ROS) that it mitigates with the help of a unique oxidase, known as alternative oxidase (AOX). High iron induces AOX1/2 that limits mitochondrial accumulation of ROS. Genetic elimination of AOX1/2 resulted in diminished virulence during oropharyngeal candidiasis in high iron mice. Since human mitochondria lack AOX protein, it represents a unique target for treatment of fungal infections.
Collapse
Affiliation(s)
- Rishabh Sharma
- Oral Microbiome Research Laboratory, Kornberg School of Dentistry, Temple University, Philadelphia, Pennsylvania, USA
| | - Andrew A. Gibb
- Department of Cardiovascular Sciences, Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Kelcie Barnts
- Oral and Maxillofacial Pathology, Medicine and Surgery, Kornberg School of Dentistry, Temple University, Philadelphia, Pennsylvania, USA
| | - John W. Elrod
- Department of Cardiovascular Sciences, Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Sumant Puri
- Oral Microbiome Research Laboratory, Kornberg School of Dentistry, Temple University, Philadelphia, Pennsylvania, USA
| |
Collapse
|
10
|
Silao FGS, Jiang T, Bereczky-Veress B, Kühbacher A, Ryman K, Uwamohoro N, Jenull S, Nogueira F, Ward M, Lion T, Urban CF, Rupp S, Kuchler K, Chen C, Peuckert C, Ljungdahl PO. Proline catabolism is a key factor facilitating Candida albicans pathogenicity. PLoS Pathog 2023; 19:e1011677. [PMID: 37917600 PMCID: PMC10621835 DOI: 10.1371/journal.ppat.1011677] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 09/11/2023] [Indexed: 11/04/2023] Open
Abstract
Candida albicans, the primary etiology of human mycoses, is well-adapted to catabolize proline to obtain energy to initiate morphological switching (yeast to hyphal) and for growth. We report that put1-/- and put2-/- strains, carrying defective Proline UTilization genes, display remarkable proline sensitivity with put2-/- mutants being hypersensitive due to the accumulation of the toxic intermediate pyrroline-5-carboxylate (P5C), which inhibits mitochondrial respiration. The put1-/- and put2-/- mutations attenuate virulence in Drosophila and murine candidemia models and decrease survival in human neutrophils and whole blood. Using intravital 2-photon microscopy and label-free non-linear imaging, we visualized the initial stages of C. albicans cells infecting a kidney in real-time, directly deep in the tissue of a living mouse, and observed morphological switching of wildtype but not of put2-/- cells. Multiple members of the Candida species complex, including C. auris, are capable of using proline as a sole energy source. Our results indicate that a tailored proline metabolic network tuned to the mammalian host environment is a key feature of opportunistic fungal pathogens.
Collapse
Affiliation(s)
- Fitz Gerald S. Silao
- Department of Molecular Biosciences, The Wenner-Gren Institute, Science for Life Laboratory, Stockholm University, Solna, Sweden
| | - Tong Jiang
- Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai, China
| | - Biborka Bereczky-Veress
- Intravital Microscopy Facility, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Andreas Kühbacher
- Department of Molecular Biotechnology, Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB, Stuttgart, Germany
| | - Kicki Ryman
- Department of Molecular Biosciences, The Wenner-Gren Institute, Science for Life Laboratory, Stockholm University, Solna, Sweden
| | - Nathalie Uwamohoro
- Clinical Microbiology and Umeå Centre for Microbial Research (UCMR), Umeå University Umeå, Sweden
| | - Sabrina Jenull
- Medical University of Vienna, Max F. Perutz Laboratories GmbH, Department of Medical Biochemistry, Vienna, Austria
- Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Filomena Nogueira
- Medical University of Vienna, Max F. Perutz Laboratories GmbH, Department of Medical Biochemistry, Vienna, Austria
- St. Anna Kinderkrebsforschung e.V., Children’s Cancer Research Institute, Vienna, Austria
| | - Meliza Ward
- Department of Molecular Biosciences, The Wenner-Gren Institute, Science for Life Laboratory, Stockholm University, Solna, Sweden
| | - Thomas Lion
- St. Anna Kinderkrebsforschung e.V., Children’s Cancer Research Institute, Vienna, Austria
| | - Constantin F. Urban
- Clinical Microbiology and Umeå Centre for Microbial Research (UCMR), Umeå University Umeå, Sweden
| | - Steffen Rupp
- Department of Molecular Biotechnology, Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB, Stuttgart, Germany
| | - Karl Kuchler
- Medical University of Vienna, Max F. Perutz Laboratories GmbH, Department of Medical Biochemistry, Vienna, Austria
| | - Changbin Chen
- Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai, China
| | - Christiane Peuckert
- Intravital Microscopy Facility, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Per O. Ljungdahl
- Department of Molecular Biosciences, The Wenner-Gren Institute, Science for Life Laboratory, Stockholm University, Solna, Sweden
| |
Collapse
|
11
|
Pan B, Weerasinghe H, Sezmis A, McDonald MJ, Traven A, Thompson P, Simm C. Leveraging the MMV Pathogen Box to Engineer an Antifungal Compound with Improved Efficacy and Selectivity against Candida auris. ACS Infect Dis 2023; 9:1901-1917. [PMID: 37756147 DOI: 10.1021/acsinfecdis.3c00199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/29/2023]
Abstract
Fungal infections pose a significant and increasing threat to human health, but the current arsenal of antifungal drugs is inadequate. We screened the Medicines for Malaria Venture (MMV) Pathogen Box for new antifungal agents against three of the most critical Candida species (Candida albicans, Candida auris, and Candida glabrata). Of the 14 identified hit compounds, most were active against C. albicans and C. auris. We selected the pyrazolo-pyrimidine MMV022478 for chemical modifications to build structure-activity relationships and study their antifungal properties. Two analogues, 7a and 8g, with distinct fluorine substitutions, greatly improved the efficacy against C. auris and inhibited fungal replication inside immune cells. Additionally, analogue 7a had improved selectivity toward fungal killing compared to mammalian cytotoxicity. Evolution experiments generating MMV022478-resistant isolates revealed a change in morphology from oblong to round cells. Most notably, the resistant isolates blocked the uptake of the fluorescent dye rhodamine 6G and showed reduced susceptibility toward fluconazole, indicative of structural changes in the yeast cell surface. In summary, our study identified a promising antifungal compound with activity against high-priority fungal pathogens. Additionally, we demonstrated how structure-activity relationship studies of known and publicly available compounds can expand the repertoire of molecules with antifungal efficacy and reduced cytotoxicity to drive the development of novel therapeutics.
Collapse
Affiliation(s)
- Baolong Pan
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, VIC, Australia
| | - Harshini Weerasinghe
- Infection Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800, VIC, Australia
- Centre to Impact AMR, Monash University, Clayton 3800, VIC, Australia
| | - Aysha Sezmis
- School of Biological Sciences, Monash University, Clayton 3800, VIC, Australia
| | - Michael J McDonald
- Centre to Impact AMR, Monash University, Clayton 3800, VIC, Australia
- School of Biological Sciences, Monash University, Clayton 3800, VIC, Australia
| | - Ana Traven
- Infection Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800, VIC, Australia
- Centre to Impact AMR, Monash University, Clayton 3800, VIC, Australia
| | - Philip Thompson
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, VIC, Australia
| | - Claudia Simm
- Infection Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800, VIC, Australia
- Centre to Impact AMR, Monash University, Clayton 3800, VIC, Australia
| |
Collapse
|
12
|
Manso JA, Carabias A, Sárkány Z, de Pereda JM, Pereira PJB, Macedo-Ribeiro S. Pathogen-specific structural features of Candida albicans Ras1 activation complex: uncovering new antifungal drug targets. mBio 2023; 14:e0063823. [PMID: 37526476 PMCID: PMC10470544 DOI: 10.1128/mbio.00638-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 06/16/2023] [Indexed: 08/02/2023] Open
Abstract
An important feature associated with Candida albicans pathogenicity is its ability to switch between yeast and hyphal forms, a process in which CaRas1 plays a key role. CaRas1 is activated by the guanine nucleotide exchange factor (GEF) CaCdc25, triggering hyphal growth-related signaling pathways through its conserved GTP-binding (G)-domain. An important function in hyphal growth has also been proposed for the long hypervariable region downstream the G-domain, whose unusual content of polyglutamine stretches and Q/N repeats make CaRas1 unique within Ras proteins. Despite its biological importance, both the structure of CaRas1 and the molecular basis of its activation by CaCdc25 remain unexplored. Here, we show that CaRas1 has an elongated shape and limited conformational flexibility and that its hypervariable region contains helical structural elements, likely forming an intramolecular coiled-coil. Functional assays disclosed that CaRas1-activation by CaCdc25 is highly efficient, with activities up to 2,000-fold higher than reported for human GEFs. The crystal structure of the CaCdc25 catalytic region revealed an active conformation for the α-helical hairpin, critical for CaRas1-activation, unveiling a specific region exclusive to CTG-clade species. Structural studies on CaRas1/CaCdc25 complexes also revealed an interaction surface clearly distinct from that of homologous human complexes. Furthermore, we identified an inhibitory synthetic peptide, prompting the proposal of a key regulatory mechanism for CaCdc25. To our knowledge, this is the first report of specific inhibition of the CaRas1-activation via targeting its GEF. This, together with their unique pathogen-structural features, disclose a set of novel strategies to specifically block this important virulence-related mechanism. IMPORTANCE Candida albicans is the main causative agent of candidiasis, the commonest fungal infection in humans. The eukaryotic nature of C. albicans and the rapid emergence of antifungal resistance raise the challenge of identifying novel drug targets to battle this prevalent and life-threatening disease. CaRas1 and CaCdc25 are key players in the activation of signaling pathways triggering multiple virulence traits, including the yeast-to-hypha interconversion. The structural similarity of the conserved G-domain of CaRas1 to those of human homologs and the lack of structural information on CaCdc25 has impeded progress in targeting these proteins. The unique structural and functional features for CaRas1 and CaCdc25 presented here, together with the identification of a synthetic peptide capable of specifically inhibiting the GEF activity of CaCdc25, open new possibilities to uncover new antifungal drug targets against C. albicans virulence.
Collapse
Affiliation(s)
- José A. Manso
- IBMC–Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- i3S–Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - Arturo Carabias
- Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas-University of Salamanca, Salamanca, Spain
| | - Zsuzsa Sárkány
- IBMC–Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- i3S–Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - José M. de Pereda
- Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas-University of Salamanca, Salamanca, Spain
| | - Pedro José Barbosa Pereira
- IBMC–Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- i3S–Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - Sandra Macedo-Ribeiro
- IBMC–Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- i3S–Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| |
Collapse
|
13
|
Wilson HB, Lorenz MC. Candida albicans Hyphal Morphogenesis within Macrophages Does Not Require Carbon Dioxide or pH-Sensing Pathways. Infect Immun 2023; 91:e0008723. [PMID: 37078861 PMCID: PMC10187119 DOI: 10.1128/iai.00087-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 03/29/2023] [Indexed: 04/21/2023] Open
Abstract
The opportunistic fungal pathogen Candida albicans has evolved a variety of mechanisms for surviving inside and escaping macrophages, including the initiation of filamentous growth. Although several distinct models have been proposed to explain this process at the molecular level, the signals driving hyphal morphogenesis in this context have yet to be clarified. Here, we evaluate the following three molecular signals as potential hyphal inducers within macrophage phagosomes: CO2, intracellular pH, and extracellular pH. Additionally, we revisit previous work suggesting that the intracellular pH of C. albicans fluctuates in tandem with morphological changes in vitro. Using time-lapse microscopy, we observed that C. albicans mutants lacking components of the CO2-sensing pathway were able to undergo hyphal morphogenesis within macrophages. Similarly, a rim101Δ strain was competent in hyphal induction, suggesting that neutral/alkaline pH sensing is not necessary for the initiation of morphogenesis within phagosomes either. Contrary to previous findings, single-cell pH-tracking experiments revealed that the cytosolic pH of C. albicans remains tightly regulated both within macrophage phagosomes and under a variety of in vitro conditions throughout the process of morphogenesis. This finding suggests that intracellular pH is not a signal contributing to morphological changes.
Collapse
Affiliation(s)
- Hannah B. Wilson
- Graduate School for Biomedical Sciences, University of Texas Science Center at Houston, Houston, Texas, USA
- Department of Microbiology and Molecular Genetics, University of Texas McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Michael C. Lorenz
- Department of Microbiology and Molecular Genetics, University of Texas McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
| |
Collapse
|
14
|
Liu N, Tu J, Huang Y, Yang W, Wang Q, Li Z, Sheng C. Target- and prodrug-based design for fungal diseases and cancer-associated fungal infections. Adv Drug Deliv Rev 2023; 197:114819. [PMID: 37024014 DOI: 10.1016/j.addr.2023.114819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 03/28/2023] [Accepted: 03/31/2023] [Indexed: 04/07/2023]
Abstract
Invasive fungal infections (IFIs) are emerging as a serious threat to public health and are associated with high incidence and mortality. IFIs also represent a frequent complication in patients with cancer who are undergoing chemotherapy. However, effective and safe antifungal agents remain limited, and the development of severe drug resistance further undermines the efficacy of antifungal therapy. Therefore, there is an urgent need for novel antifungal agents to treat life-threatening fungal diseases, especially those with new mode of action, favorable pharmacokinetic profiles, and anti-resistance activity. In this review, we summarize new antifungal targets and target-based inhibitor design, with a focus on their antifungal activity, selectivity, and mechanism. We also illustrate the prodrug design strategy used to improve the physicochemical and pharmacokinetic profiles of antifungal agents. Dual-targeting antifungal agents offer a new strategy for the treatment of resistant infections and cancer-associated fungal infections.
Collapse
|
15
|
Zeng L, Huang Y, Tan J, Peng J, Hu N, Liu Q, Cao Y, Zhang Y, Chen J, Huang X. QCR7 affects the virulence of Candida albicans and the uptake of multiple carbon sources present in different host niches. Front Cell Infect Microbiol 2023; 13:1136698. [PMID: 36923588 PMCID: PMC10009220 DOI: 10.3389/fcimb.2023.1136698] [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: 01/03/2023] [Accepted: 02/09/2023] [Indexed: 03/02/2023] Open
Abstract
Background Candida albicans is a commensal yeast that may cause life-threatening infections. Studies have shown that the cytochrome b-c1 complex subunit 7 gene (QCR7) of C. albicans encodes a protein that forms a component of the mitochondrial electron transport chain complex III, making it an important target for studying the virulence of this yeast. However, to the best of our knowledge, the functions of QCR7 have not yet been characterized. Methods A QCR7 knockout strain was constructed using SN152, and BALb/c mice were used as model animals to determine the role of QCR7 in the virulence of C. albicans. Subsequently, the effects of QCR7 on mitochondrial functions and use of carbon sources were investigated. Next, its mutant biofilm formation and hyphal growth maintenance were compared with those of the wild type. Furthermore, the transcriptome of the qcr7Δ/Δ mutant was compared with that of the WT strain to explore pathogenic mechanisms. Results Defective QCR7 reduced recruitment of inflammatory cells and attenuated the virulence of C. albicans infection in vivo. Furthermore, the mutant influenced the use of multiple alternative carbon sources that exist in several host niches (GlcNAc, lactic acid, and amino acid, etc.). Moreover, it led to mitochondrial dysfunction. Furthermore, the QCR7 knockout strain showed defects in biofilm formation or the maintenance of filamentous growth. The overexpression of cell-surface-associated genes (HWP1, YWP1, XOG1, and SAP6) can restore defective virulence phenotypes and the carbon-source utilization of qcr7Δ/Δ. Conclusion This study provides new insights into the mitochondria-based metabolism of C. albicans, accounting for its virulence and the use of variable carbon sources that promote C. albicans to colonize host niches.
Collapse
Affiliation(s)
- Lingbing Zeng
- The First Affiliated Hospital of Nanchang University, School of Public Health, Jiangxi Medical College, Nanchang University, Nanchang, China
- Department of Medical Microbiology, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Yongcheng Huang
- School of Public Health, Jiangxi Medical College, Nanchang University, Nanchang, China
- Jiangxi Provincial Key Laboratory of Preventive Medicine, Nanchang University, Nanchang, China
| | - Junjun Tan
- Department of Medical Microbiology, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Jun Peng
- Department of Medical Microbiology, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Niya Hu
- The First Affiliated Hospital of Nanchang University, School of Public Health, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Qiong Liu
- Department of Medical Microbiology, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - YanLi Cao
- Department of Medical Microbiology, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Yuping Zhang
- Department of Medical Microbiology, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Junzhu Chen
- Department of Medical Microbiology, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Xiaotian Huang
- The First Affiliated Hospital of Nanchang University, School of Public Health, Jiangxi Medical College, Nanchang University, Nanchang, China
- Department of Medical Microbiology, Jiangxi Medical College, Nanchang University, Nanchang, China
- School of Public Health, Jiangxi Medical College, Nanchang University, Nanchang, China
- Jiangxi Provincial Key Laboratory of Preventive Medicine, Nanchang University, Nanchang, China
| |
Collapse
|
16
|
Zeng G, Neo SP, Pang LM, Gao J, Chong SC, Gunaratne J, Wang Y. Comprehensive Interactome Analysis for the Sole Adenylyl Cyclase Cyr1 of Candida albicans. Microbiol Spectr 2022; 10:e0393422. [PMID: 36314909 PMCID: PMC9769623 DOI: 10.1128/spectrum.03934-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 10/06/2022] [Indexed: 11/06/2022] Open
Abstract
Cyr1, the sole adenylyl cyclase of the fungal pathogen Candida albicans, is a central component of the cAMP/protein kinase A signaling pathway that controls the yeast-to-hypha transition. Cyr1 is a multivalent sensor and integrator of various external and internal signals. To better understand how these signals are relayed to Cyr1 to regulate its activity, we sought to establish the interactome of Cyr1 by using stable isotope labeling by amino acids in cell culture (SILAC)-based quantitative proteomics to identify the proteins that coimmunoprecipitated with Cyr1. The method identified 36 proteins as candidates for authentic Cyr1-interacting partners, together with two known Cyr1-binding proteins, Cap1 and Act1. Fourteen identified proteins belonged to three functional groups, including actin regulation, cell wall components, and mitochondrial activities, that are known to play important roles in cell morphogenesis. To validate the proteomics data, we used biochemical and genetic methods to characterize two cell wall-related proteins, Mp65 and Sln1. First, coimmunoprecipitation confirmed their physical association with Cyr1. Second, deleting either MP65 or SLN1 resulted in severe defects in filamentation on serum plates. This study establishes the first Cyr1 interactome and uncovers a potential role for cell wall proteins in directly regulating Cyr1 activity to determine growth forms in C. albicans. IMPORTANCE A critical virulence trait of the human fungal pathogen Candida albicans is its ability to undergo the yeast-to-hypha transition in response to diverse environmental and cellular stimuli. Previous studies suggested that the sole adenylyl cyclase of C. albicans, Cyr1, is a multivalent signal sensor and integrator synthesizing cAMP to activate the downstream hypha-promoting events through the cAMP/protein kinase A pathway. To fully understand how Cyr1 senses and processes multiple stimuli to generate appropriate signal outputs, it was necessary to identify and characterize Cyr1-interacting partners. This study employed SILAC-based quantitative proteomic approaches and identified 36 Cyr1-associated proteins, many having functions associated with hyphal morphogenesis. Coimmunoprecipitation verified two cell surface proteins, Mp65 and Sln1. Furthermore, genetic and phenotypic analyses demonstrated the cAMP-dependent roles of these two proteins in determining hyphal growth. Our study establishes the first Cyr1 interactome and uncovers new Cyr1 regulators that mediate cell surface signals to influence the growth mode of C. albicans.
Collapse
Affiliation(s)
| | - Suat Peng Neo
- Quantitative Proteomics Group, Institute of Molecular and Cell Biology, Singapore
| | | | | | | | - Jayantha Gunaratne
- Quantitative Proteomics Group, Institute of Molecular and Cell Biology, Singapore
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Yue Wang
- Infectious Diseases Labs, Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| |
Collapse
|
17
|
Zhao B, He D, Gao S, Zhang Y, Wang L. Hypothetical protein FoDbp40 influences the growth and virulence of Fusarium oxysporum by regulating the expression of isocitrate lyase. Front Microbiol 2022; 13:1050637. [DOI: 10.3389/fmicb.2022.1050637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 11/04/2022] [Indexed: 11/29/2022] Open
Abstract
Fungal growth is closely related to virulence. Finding the key genes and pathways that regulate growth can help elucidate the regulatory mechanisms of fungal growth and virulence in efforts to locate new drug targets. Fusarium oxysporum is an important plant pathogen and human opportunistic pathogen that has research value in agricultural and medicinal fields. A mutant of F. oxysporum with reduced growth was obtained by Agrobacterium tumefaciens-mediated transformation, the transferred DNA (T-DNA) interrupted gene in this mutant coded a hypothetical protein that we named FoDbp40. FoDbp40 has an unknown function, but we chose to explore its possible functions as it may play a role in fungal growth regulatory mechanisms. Results showed that F. oxysporum growth and virulence decreased after FoDbp40 deletion. FOXG_05529 (NCBI Gene ID, isocitrate lyase, ICL) was identified as a key gene that involved in the reduced growth of this mutant. Deletion of FoDbp40 results in a decrease of more than 80% in ICL expression and activity, succinate level, and energy level, plus a decrease in phosphorylated mammalian target of rapamycin level and an increase in phosphorylated 5′-adenosine monophosphate activated protein kinase level. In summary, our study found that the FoDbp40 regulates the expression of ICL at a transcriptional level and affects energy levels and downstream related pathways, thereby regulating the growth and virulence of F. oxysporum.
Collapse
|
18
|
Sriram K. A mathematical model captures the role of adenyl cyclase Cyr1 and guanidine exchange factor Ira2 in creating a growth-to-hyphal bistable switch in Candida albicans. FEBS Open Bio 2022; 12:1700-1716. [PMID: 35979612 PMCID: PMC9527597 DOI: 10.1002/2211-5463.13470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 07/29/2022] [Accepted: 08/15/2022] [Indexed: 12/14/2022] Open
Abstract
Recent biochemical experiments have indicated that in Candida albicans, a commensal fungal pathogen, the Ras signaling pathway plays a significant role in the yeast-to-hyphal transition; specifically, two enzymes in this pathway, Adenyl Cyclase Cyr1 and GTPase activating protein Ira2, facilitate this transition, in the presence of energy sensor ATP. However, the precise mechanism by which protein interactions between Ira2 and Cyr1 and the energy sensor ATP result in the yeast-to-hyphal transition and create a switch-like process are unknown. We propose a new set of biochemical reaction steps that captures all the essential interactions between Ira2, Cyr1, and ATP in the Ras pathway. With the help of chemical reaction network theory, we demonstrate that this set of biochemical reaction steps results in bistability. Further, bifurcation analysis of the differential equations based on this set of reaction steps supports the existence of a bistable switch, and this switch may act as a checkpoint mechanism for the promotion of growth-to-hyphal transition in C. albicans.
Collapse
Affiliation(s)
- K Sriram
- Department of Computational Biology, Center for Computational BiologyIIIT‐DelhiIndia
| |
Collapse
|
19
|
Abstract
The tight association of Candida albicans with the human host has driven the evolution of mechanisms that permit metabolic flexibility. Amino acids, present in a free or peptide-bound form, are abundant carbon and nitrogen sources in many host niches. In C. albicans, the capacity to utilize certain amino acids, like proline, is directly connected to fungal morphogenesis and virulence. Yet the precise nature of proline sensing and uptake in this pathogenic fungus has not been investigated. Since C. albicans encodes 10 putative orthologs of the four Saccharomyces cerevisiae proline transporters, we tested deletion strains of the respective genes and identified Gnp2 (CR_09920W) as the main C. albicans proline permease. In addition, we found that this specialization of Gnp2 was reflected in its transcriptional regulation and further assigned distinct substrate specificities for the other orthologs, indicating functional differences of the C. albicans amino acid permeases compared to the model yeast. The physiological relevance of proline uptake is exemplified by the findings that strains lacking GNP2 were unable to filament in response to extracellular proline and had a reduced capacity to damage macrophages and impaired survival following phagocytosis. Furthermore, GNP2 deletion rendered the cells more sensitive to oxidative stress, illustrating new connections between amino acid uptake and stress adaptation in C. albicans. IMPORTANCE The utilization of various nutrients is of paramount importance for the ability of Candida albicans to successfully colonize and infect diverse host niches. In this context, amino acids are of special interest due to their ubiquitous availability, relevance for fungal growth, and direct influence on virulence traits like filamentation. In this study, we identify a specialized proline transporter in C. albicans encoded by GNP2. The corresponding amino acid permease is essential for proline-induced filamentation, oxidative stress resistance, and fungal survival following interaction with macrophages. Altogether, this work highlights the importance of amino acid uptake for metabolic and stress adaptation in this fungus.
Collapse
|
20
|
Jin X, Zhang M, Lu J, Duan X, Chen J, Liu Y, Chang W, Lou H. Hinokitiol chelates intracellular iron to retard fungal growth by disturbing mitochondrial respiration. J Adv Res 2022; 34:65-77. [PMID: 35024181 PMCID: PMC8655124 DOI: 10.1016/j.jare.2021.06.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 06/01/2021] [Accepted: 06/15/2021] [Indexed: 12/30/2022] Open
Abstract
Introduction The increasing morbidity of fungal infections and the prevalence of drug resistance highlighted the discovery of novel antifungal agents and investigation of their modes of action. Iron chelators have been used to treat superficial fungal infections or potentiate the efficacy of certain antifungal drugs. Hinokitiol exhibits potent antifungal activity and iron-chelating ability. However, their relationships have not been established. Objectives This study aims to explore the selectivity of hinokitiol against fungal cells and mammalian cells and determine the role of iron-chelating for the antifungal activity of hinokitiol. Methods Iron probe FeRhonox-1 was used to determine intracellular Fe2+ content. 5-Cyano-2,3-ditolyl tetrazolium chloride probe and Cell Counting Kit-8 were used to detect the mitochondrial respiratory activities. Quantitative real-time PCR and rescue experiments were performed to determine the effect of iron on the antifungal activity of hinokitiol. The effects of hinokitiol on fungal mitochondria were further evaluated using reactive oxygen species probes and several commercial Assay Kits. The ability of hinokitiol to induce resistance in Candida species was carried out using a serial passage method. The in vivo therapeutic effect of hinokitiol was evaluated using Galleria mellonella as an infectious model. Results Hinokitiol was effective against a panel of Candida strains with multiple azole-resistant mechanisms and persistently inhibited Candida albicans growth. Mechanism investigations revealed that hinokitiol chelated fungal intracellular iron and inhibited the respiration of fungal cells but had minor effects on mammalian cells. Hinokitiol further inhibited the activities of mitochondrial respiratory chain complexes I and II and reduced mitochondrial membrane potential, thereby decreasing intracellular ATP synthesis and increasing detrimental intracellular reductive stress. Moreover, hinokitiol exhibited low potential for inducing resistance in several Candida species and greatly improved the survival of Candida-infected Galleria mellonella. Conclusions These findings suggested the potential application of hinokitiol as an iron chelator to treat fungal infections.
Collapse
Affiliation(s)
- Xueyang Jin
- Department of Natural Product Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, China
| | - Ming Zhang
- Institute of Medical Science, The Second Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, China
| | - Jinghui Lu
- Department of Natural Product Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, China
| | - Ximeng Duan
- Department of Natural Product Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, China
| | - Jinyao Chen
- Department of Natural Product Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, China
| | - Yue Liu
- Department of Natural Product Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, China
| | - Wenqiang Chang
- Department of Natural Product Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, China
| | - Hongxiang Lou
- Department of Natural Product Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, China
| |
Collapse
|
21
|
Hollomon JM, Liu Z, Rusin SF, Jenkins NP, Smith AK, Koeppen K, Kettenbach AN, Myers LC, Hogan DA. The Candida albicans Cdk8-dependent phosphoproteome reveals repression of hyphal growth through a Flo8-dependent pathway. PLoS Genet 2022; 18:e1009622. [PMID: 34982775 PMCID: PMC8769334 DOI: 10.1371/journal.pgen.1009622] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 01/19/2022] [Accepted: 12/06/2021] [Indexed: 12/26/2022] Open
Abstract
Ssn3, also known as Cdk8, is a member of the four protein Cdk8 submodule within the multi-subunit Mediator complex involved in the co-regulation of transcription. In Candida albicans, the loss of Ssn3 kinase activity affects multiple phenotypes including cellular morphology, metabolism, nutrient acquisition, immune cell interactions, and drug resistance. In these studies, we generated a strain in which Ssn3 was replaced with a functional variant of Ssn3 that can be rapidly and selectively inhibited by the ATP analog 3-MB-PP1. Consistent with ssn3 null mutant and kinase dead phenotypes, inhibition of Ssn3 kinase activity promoted hypha formation. Furthermore, the increased expression of hypha-specific genes was the strongest transcriptional signal upon inhibition of Ssn3 in transcriptomics analyses. Rapid inactivation of Ssn3 was used for phosphoproteomic studies performed to identify Ssn3 kinase substrates associated with filamentation potential. Both previously validated and novel Ssn3 targets were identified. Protein phosphorylation sites that were reduced specifically upon Ssn3 inhibition included two sites in Flo8 which is a transcription factor known to positively regulate C. albicans morphology. Mutation of the two Flo8 phosphosites (threonine 589 and serine 620) was sufficient to increase Flo8-HA levels and Flo8 dependent transcriptional and morphological changes, suggesting that Ssn3 kinase activity negatively regulates Flo8.Under embedded conditions, when ssn3Δ/Δ and efg1Δ/Δ mutants were hyperfilamentous, FLO8 was essential for hypha formation. Previous work has also shown that loss of Ssn3 activity leads to increased alkalinization of medium with amino acids. Here, we show that the ssn3Δ/Δ medium alkalinization phenotype, which is dependent on STP2, a transcription factor involved in amino acid utilization, also requires FLO8 and EFG1. Together, these data show that Ssn3 activity can modulate Flo8 and its direct and indirect interactions in different ways, and underscores the potential importance of considering Ssn3 function in the control of transcription factor activities. In Candida albicans, Ssn3 kinase activity co-regulates the transcription of numerous genes involved in hyphal growth, metabolism and nutrient acquisition, immune cell interactions, and drug resistance. Using a strain in which Ssn3 could be rapidly and selectively inhibited, we identified both known and novel Ssn3 targets. We identified two phosphosites in Flo8, a regulator of morphology and virulence, that were shown to negatively regulate Flo8 levels and activity. The data and tools presented here will enable a better understanding of how Ssn3 impacts transcriptional and post-transcriptional regulation in order to coordinate processes during physiological and morphological transitions as well as during steady state growth.
Collapse
Affiliation(s)
- Jeffrey M. Hollomon
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Zhongle Liu
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Scott F. Rusin
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
- Norris Cotton Cancer Center, Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center at Dartmouth, Lebanon, New Hampshire, United States of America
| | - Nicole P. Jenkins
- Norris Cotton Cancer Center, Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center at Dartmouth, Lebanon, New Hampshire, United States of America
| | - Allia K. Smith
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Katja Koeppen
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Arminja N. Kettenbach
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
- Norris Cotton Cancer Center, Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center at Dartmouth, Lebanon, New Hampshire, United States of America
| | - Lawrence C. Myers
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
- Department of Medical Education, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
- * E-mail: (LCM); (DAH)
| | - Deborah A. Hogan
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
- * E-mail: (LCM); (DAH)
| |
Collapse
|
22
|
Amino Acid Sensing and Assimilation by the Fungal Pathogen Candida albicans in the Human Host. Pathogens 2021; 11:pathogens11010005. [PMID: 35055954 PMCID: PMC8781990 DOI: 10.3390/pathogens11010005] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 12/17/2021] [Accepted: 12/19/2021] [Indexed: 01/04/2023] Open
Abstract
Nutrient uptake is essential for cellular life and the capacity to perceive extracellular nutrients is critical for coordinating their uptake and metabolism. Commensal fungal pathogens, e.g., Candida albicans, have evolved in close association with human hosts and are well-adapted to using diverse nutrients found in discrete host niches. Human cells that cannot synthesize all amino acids require the uptake of the “essential amino acids” to remain viable. Consistently, high levels of amino acids circulate in the blood. Host proteins are rich sources of amino acids but their use depends on proteases to cleave them into smaller peptides and free amino acids. C. albicans responds to extracellular amino acids by pleiotropically enhancing their uptake and derive energy from their catabolism to power opportunistic virulent growth. Studies using Saccharomyces cerevisiae have established paradigms to understand metabolic processes in C. albicans; however, fundamental differences exist. The advent of CRISPR/Cas9-based methods facilitate genetic analysis in C. albicans, and state-of-the-art molecular biological techniques are being applied to directly examine growth requirements in vivo and in situ in infected hosts. The combination of divergent approaches can illuminate the biological roles of individual cellular components. Here we discuss recent findings regarding nutrient sensing with a focus on amino acid uptake and metabolism, processes that underlie the virulence of C. albicans.
Collapse
|
23
|
The δ subunit of F 1F o-ATP synthase is required for pathogenicity of Candida albicans. Nat Commun 2021; 12:6041. [PMID: 34654833 PMCID: PMC8519961 DOI: 10.1038/s41467-021-26313-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 09/24/2021] [Indexed: 11/08/2022] Open
Abstract
Fungal infections, especially candidiasis and aspergillosis, claim a high fatality rate. Fungal cell growth and function requires ATP, which is synthesized mainly through oxidative phosphorylation, with the key enzyme being F1Fo-ATP synthase. Here, we show that deletion of the Candida albicans gene encoding the δ subunit of the F1Fo-ATP synthase (ATP16) abrogates lethal infection in a mouse model of systemic candidiasis. The deletion does not substantially affect in vitro fungal growth or intracellular ATP concentrations, because the decrease in oxidative phosphorylation-derived ATP synthesis is compensated by enhanced glycolysis. However, the ATP16-deleted mutant displays decreased phosphofructokinase activity, leading to low fructose 1,6-bisphosphate levels, reduced activity of Ras1-dependent and -independent cAMP-PKA pathways, downregulation of virulence factors, and reduced pathogenicity. A structure-based virtual screening of small molecules leads to identification of a compound potentially targeting the δ subunit of fungal F1Fo-ATP synthases. The compound induces in vitro phenotypes similar to those observed in the ATP16-deleted mutant, and protects mice from succumbing to invasive candidiasis. Our findings indicate that F1Fo-ATP synthase δ subunit is required for C. albicans lethal infection and represents a potential therapeutic target.
Collapse
|
24
|
Min K, Jannace TF, Si H, Veeramah KR, Haley JD, Konopka JB. Integrative multi-omics profiling reveals cAMP-independent mechanisms regulating hyphal morphogenesis in Candida albicans. PLoS Pathog 2021; 17:e1009861. [PMID: 34398936 PMCID: PMC8389844 DOI: 10.1371/journal.ppat.1009861] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 08/26/2021] [Accepted: 08/02/2021] [Indexed: 12/24/2022] Open
Abstract
Microbial pathogens grow in a wide range of different morphologies that provide distinct advantages for virulence. In the fungal pathogen Candida albicans, adenylyl cyclase (Cyr1) is thought to be a master regulator of the switch to invasive hyphal morphogenesis and biofilm formation. However, faster growing cyr1Δ/Δ pseudorevertant (PR) mutants were identified that form hyphae in the absence of cAMP. Isolation of additional PR mutants revealed that their improved growth was due to loss of one copy of BCY1, the negative regulatory subunit of protein kinase A (PKA) from the left arm of chromosome 2. Furthermore, hyphal morphogenesis was improved in some of PR mutants by multigenic haploinsufficiency resulting from loss of large regions of the left arm of chromosome 2, including global transcriptional regulators. Interestingly, hyphal-associated genes were also induced in a manner that was independent of cAMP. This indicates that basal protein kinase A activity is an important prerequisite to induce hyphae, but activation of adenylyl cyclase is not needed. Instead, phosphoproteomic analysis indicated that the Cdc28 cyclin-dependent kinase and the casein kinase 1 family member Yck2 play key roles in promoting polarized growth. In addition, integrating transcriptomic and proteomic data reveals hyphal stimuli induce increased production of key transcription factors that contribute to polarized morphogenesis.
Collapse
Affiliation(s)
- Kyunghun Min
- Department of Microbiology and Immunology, Renaissance School of Medicine, Stony Brook University (SUNY), Stony Brook, New York, United States of America
| | - Thomas F. Jannace
- Department of Microbiology and Immunology, Renaissance School of Medicine, Stony Brook University (SUNY), Stony Brook, New York, United States of America
| | - Haoyu Si
- Department of Microbiology and Immunology, Renaissance School of Medicine, Stony Brook University (SUNY), Stony Brook, New York, United States of America
| | - Krishna R. Veeramah
- Department of Ecology and Evolution, Stony Brook University (SUNY), Stony Brook, New York, United States of America
| | - John D. Haley
- Department of Pathology, Renaissance School of Medicine, Stony Brook University (SUNY), Stony Brook, New York, United States of America
- Biological Mass Spectrometry Shared Resource, Renaissance School of Medicine, Stony Brook University (SUNY), Stony Brook, New York, United States of America
| | - James B. Konopka
- Department of Microbiology and Immunology, Renaissance School of Medicine, Stony Brook University (SUNY), Stony Brook, New York, United States of America
- * E-mail:
| |
Collapse
|
25
|
Hameed S, Hans S, Singh S, Dhiman R, Monasky R, Pandey RP, Thangamani S, Fatima Z. Revisiting the Vital Drivers and Mechanisms of β-Glucan Masking in Human Fungal Pathogen, Candida albicans. Pathogens 2021; 10:942. [PMID: 34451406 PMCID: PMC8399646 DOI: 10.3390/pathogens10080942] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 07/14/2021] [Accepted: 07/22/2021] [Indexed: 12/31/2022] Open
Abstract
Among the several human fungal pathogens, Candida genus represents one of the most implicated in the clinical scenario. There exist several distinctive features that govern the establishment of Candida infections in addition to their capacity to adapt to multiple stress conditions inside humans which also include evasion of host immune responses. The complex fungal cell wall of the prevalent pathogen, Candida albicans, is one of the main targets of antifungal drugs and recognized by host immune cells. The wall consists of tiered arrangement of an outer thin but dense covering of mannan and inner buried layers of β-glucan and chitin. However, the pathogenic fungi adopt strategies to evade immune recognition by masking these molecules. This capacity to camouflage the immunogenic polysaccharide β-glucan from the host is a key virulence factor of C. albicans. The present review is an attempt to collate various underlying factors and mechanisms involved in Candida β-glucan masking from the available pool of knowledge and provide a comprehensive understanding. This will further improve therapeutic approaches to candidiasis by identifying new antifungal targets that blocks fungal immune evasion.
Collapse
Affiliation(s)
- Saif Hameed
- Amity Institute of Biotechnology, Amity University Haryana, Gurugram 122413, India; (S.H.); (S.H.); (S.S.)
| | - Sandeep Hans
- Amity Institute of Biotechnology, Amity University Haryana, Gurugram 122413, India; (S.H.); (S.H.); (S.S.)
| | - Shweta Singh
- Amity Institute of Biotechnology, Amity University Haryana, Gurugram 122413, India; (S.H.); (S.H.); (S.S.)
| | - Ruby Dhiman
- Centre for Drug Design Discovery and Development (C4D), SRM University, Sonepat 131029, India; (R.D.); (R.P.P.)
| | - Ross Monasky
- Department of Pathology and Population Medicine, College of Veterinary Medicine, Midwestern University, 19555 N. 59th Ave., Glendale, AZ 85308, USA; (R.M.); (S.T.)
| | - Ramendra Pati Pandey
- Centre for Drug Design Discovery and Development (C4D), SRM University, Sonepat 131029, India; (R.D.); (R.P.P.)
| | - Shankar Thangamani
- Department of Pathology and Population Medicine, College of Veterinary Medicine, Midwestern University, 19555 N. 59th Ave., Glendale, AZ 85308, USA; (R.M.); (S.T.)
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47906, USA
| | - Zeeshan Fatima
- Amity Institute of Biotechnology, Amity University Haryana, Gurugram 122413, India; (S.H.); (S.H.); (S.S.)
| |
Collapse
|
26
|
Black B, Lee C, Horianopoulos LC, Jung WH, Kronstad JW. Respiring to infect: Emerging links between mitochondria, the electron transport chain, and fungal pathogenesis. PLoS Pathog 2021; 17:e1009661. [PMID: 34237096 PMCID: PMC8266039 DOI: 10.1371/journal.ppat.1009661] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Affiliation(s)
- Braydon Black
- Michael Smith Laboratories, Department of Microbiology & Immunology, University of British Columbia, Vancouver, Canada
| | - Christopher Lee
- Michael Smith Laboratories, Department of Microbiology & Immunology, University of British Columbia, Vancouver, Canada
| | - Linda C. Horianopoulos
- Michael Smith Laboratories, Department of Microbiology & Immunology, University of British Columbia, Vancouver, Canada
| | - Won Hee Jung
- Department of Systems Biotechnology, Chung-Ang University, Anseong, Republic of Korea
| | - James W. Kronstad
- Michael Smith Laboratories, Department of Microbiology & Immunology, University of British Columbia, Vancouver, Canada
- * E-mail:
| |
Collapse
|
27
|
Chow EWL, Pang LM, Wang Y. From Jekyll to Hyde: The Yeast-Hyphal Transition of Candida albicans. Pathogens 2021; 10:pathogens10070859. [PMID: 34358008 PMCID: PMC8308684 DOI: 10.3390/pathogens10070859] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 06/30/2021] [Accepted: 07/05/2021] [Indexed: 12/22/2022] Open
Abstract
Candida albicans is a major fungal pathogen of humans, accounting for 15% of nosocomial infections with an estimated attributable mortality of 47%. C. albicans is usually a benign member of the human microbiome in healthy people. Under constant exposure to highly dynamic environmental cues in diverse host niches, C. albicans has successfully evolved to adapt to both commensal and pathogenic lifestyles. The ability of C. albicans to undergo a reversible morphological transition from yeast to filamentous forms is a well-established virulent trait. Over the past few decades, a significant amount of research has been carried out to understand the underlying regulatory mechanisms, signaling pathways, and transcription factors that govern the C. albicans yeast-to-hyphal transition. This review will summarize our current understanding of well-elucidated signal transduction pathways that activate C. albicans hyphal morphogenesis in response to various environmental cues and the cell cycle machinery involved in the subsequent regulation and maintenance of hyphal morphogenesis.
Collapse
Affiliation(s)
- Eve Wai Ling Chow
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore 138673, Singapore;
| | - Li Mei Pang
- National Dental Centre Singapore, National Dental Research Institute Singapore (NDRIS), 5 Second Hospital Ave, Singapore 168938, Singapore;
| | - Yue Wang
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore 138673, Singapore;
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 10 Medical Drive, Singapore 117597, Singapore
- Correspondence:
| |
Collapse
|
28
|
Zhao Y, Lyu Y, Zhang Y, Li S, Zhang Y, Liu Y, Tang C, Zhang Z, Li D, Zhang H. The fungal-specific subunit i/j of F1FO-ATP synthase stimulates the pathogenicity of Candida albicans independent of oxidative phosphorylation. Med Mycol 2021; 59:639-652. [PMID: 33269392 DOI: 10.1093/mmy/myaa094] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 10/17/2020] [Accepted: 11/03/2020] [Indexed: 12/21/2022] Open
Abstract
UNLABELLED Invasive fungal infections are a major cause of human mortality due in part to a very limited antifungal drug arsenal. The identification of fungal-specific pathogenic mechanisms is considered a crucial step to current antifungal drug development and represents a significant goal to increase the efficacy and reduce host toxicity. Although the overall architecture of F1FO-ATP synthase is largely conserved in both fungi and mammals, the subunit i/j (Su i/j, Atp18) and subunit k (Su k, Atp19) are proteins not found in mammals and specific to fungi. Here, the role of Su i/j and Su k in Candida albicans was characterized by an in vivo assessment of the virulence and in vitro growth and mitochondrial function. Strikingly, the atp18Δ/Δ mutant showed significantly reduced pathogenicity in systemic murine model. However, this substantial defect in infectivity exists without associated defects in mitochondrial oxidative phosphorylation or proliferation in vitro. Analysis of virulence-related traits reveals normal in both mutants, but shows cell wall defects in composition and architecture in the case of atp18Δ/Δ. We also find that the atp18Δ/Δ mutant is more susceptible to attack by macrophages than wild type, which may correlate well with the abnormal cell wall function and increased sensitivity to oxidative stress. In contrast, no significant changes were observed in any of these studies for the atp19Δ/Δ. These results demonstrate that the fungal-specific Su i/j, but not Su k of F1FO-ATP synthase may play a critical role in C. albicans infectivity and represent another opportunity for new therapeutic target investigation. LAY ABSTRACT This study aims to investigate biological functions of fungal-specific subunit i/j and subunit k of ATP synthase in C. albicans oxidative phosphorylation and virulence potential. Our results revealed that subunit i/j, and not subunit k, is critical for C. albicans pathogenicity.
Collapse
Affiliation(s)
- Yajing Zhao
- Department of Dermatology, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong, China
- Institute of Mycology, Jinan University, Guangzhou, Guangdong, China
| | - Yan Lyu
- Department of Dermatology, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong, China
- Institute of Mycology, Jinan University, Guangzhou, Guangdong, China
| | - Yanli Zhang
- Department of Dermatology, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong, China
- Institute of Mycology, Jinan University, Guangzhou, Guangdong, China
| | - Shuixiu Li
- Department of Dermatology, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong, China
- Institute of Mycology, Jinan University, Guangzhou, Guangdong, China
| | - Yishan Zhang
- Department of Dermatology, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong, China
- Institute of Mycology, Jinan University, Guangzhou, Guangdong, China
| | - Yuting Liu
- Department of Dermatology, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong, China
- Institute of Mycology, Jinan University, Guangzhou, Guangdong, China
| | - Chuanyan Tang
- Department of Dermatology, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong, China
- Institute of Mycology, Jinan University, Guangzhou, Guangdong, China
| | - Zhanpeng Zhang
- Department of Dermatology, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong, China
- Institute of Mycology, Jinan University, Guangzhou, Guangdong, China
| | - Dongmei Li
- Department of Microbiology and Immunology, Georgetown University Medical Center, Washington, District of Columbia, USA
| | - Hong Zhang
- Department of Dermatology, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong, China
- Institute of Mycology, Jinan University, Guangzhou, Guangdong, China
| |
Collapse
|
29
|
Khan F, Bamunuarachchi NI, Tabassum N, Jo DM, Khan MM, Kim YM. Suppression of hyphal formation and virulence of Candida albicans by natural and synthetic compounds. BIOFOULING 2021; 37:626-655. [PMID: 34284656 DOI: 10.1080/08927014.2021.1948538] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 06/18/2021] [Accepted: 06/21/2021] [Indexed: 06/13/2023]
Abstract
Candida albicans undergoes a morphological yeast-to-hyphal transition during infection, which plays a significant role in its pathogenesis. The filamentous morphology of the hyphal form has been identified as a virulence factor as it facilitates surface adherence, intertwining with biofilm, invasion, and damage to host tissues and organs. Hence, inhibition of filamentation in addition to biofilm formation is considered a viable strategy against C. albicans infections. Furthermore, a good understanding of the signaling pathways involved in response to environmental cues driving hyphal growth is also critical to an understanding of C. albicans pathogenicity and to develop novel therapies. In this review, first the clinical significance and transcriptional control of C. albicans hyphal morphogenesis are addressed. Then, various strategies employed to suppress filamentation, prevent biofilm formation, and reduce virulence are discussed. These strategies include the inhibition of C. albicans filament formation using natural or synthetic compounds, and their combination with other agents or nanoformulations.
Collapse
Affiliation(s)
- Fazlurrahman Khan
- Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan, South Korea
| | - Nilushi Indika Bamunuarachchi
- Department of Food Science and Technology, Pukyong National University, Busan, South Korea
- Department of Fisheries and Marine Sciences, Ocean University of Sri Lanka, Tangalle, Sri Lanka
| | - Nazia Tabassum
- Industrial Convergence Bionix Engineering, Pukyong National University, Busan, South Korea
| | - Du-Min Jo
- Department of Food Science and Technology, Pukyong National University, Busan, South Korea
| | - Mohammad Mansoob Khan
- Chemical Sciences, Faculty of Science, University Brunei Darussalam, Gadong, Brunei Darussalam
| | - Young-Mog Kim
- Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan, South Korea
- Department of Food Science and Technology, Pukyong National University, Busan, South Korea
| |
Collapse
|
30
|
Both Pseudomonas aeruginosa and Candida albicans Accumulate Greater Biomass in Dual-Species Biofilms under Flow. mSphere 2021; 6:e0041621. [PMID: 34160236 PMCID: PMC8265656 DOI: 10.1128/msphere.00416-21] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Microbe-microbe interactions can strongly influence growth and biofilm formation kinetics. For Pseudomonas aeruginosa and Candida albicans, which are found together in diverse clinical sites, including urinary and intravenous catheters and the lungs of individuals with cystic fibrosis (CF), we compared the kinetics of biofilm formation by each species in dual-species and single-species biofilms. We engineered fluorescent protein constructs for P. aeruginosa (producing mKO-κ) and C. albicans (producing mKate2) that did not alter growth and enabled single-cell resolution imaging by live-sample microscopy. Using these strains in an optically clear derivative of synthetic CF sputum medium, we found that both P. aeruginosa and C. albicans displayed increased biovolume accumulation—by three- and sixfold, respectively—in dual-species biofilms relative to single-species biofilms. This result was specific to the biofilm environment, as enhanced growth was not observed in planktonic cocultures. Stimulation of C. albicans biofilm formation occurred regardless of whether P. aeruginosa was added at the time of fungal inoculation or 24 h after the initiation of biofilm development. P. aeruginosa biofilm increases in cocultures did not require the Pel extracellular polysaccharide, phenazines, and siderophores known to influence C. albicans. P. aeruginosa mutants lacking Anr, LasR, and BapA were not significantly stimulated by C. albicans, but they still promoted a significant enhancement of biofilm development of the fungus, suggesting a fungal response to the presence of bacteria. Last, we showed that a set of P. aeruginosa clinical isolates also prompted an increase of biovolume by C. albicans in coculture. IMPORTANCE There is an abundance of work on both P. aeruginosa and C. albicans in isolation, and quite some work as well on the way these two microbes interact. These studies do not, however, consider biofilm environments under flow, and our results here show that the expected outcome of interaction between these two pathogens can actually be reversed under flow, from pure antagonism to an increase in biomass on the part of both. Our work also highlights the importance of cellular-scale spatial structure in biofilms for understanding multispecies population dynamics.
Collapse
|
31
|
Wang JM, Woodruff AL, Dunn MJ, Fillinger RJ, Bennett RJ, Anderson MZ. Intraspecies Transcriptional Profiling Reveals Key Regulators of Candida albicans Pathogenic Traits. mBio 2021; 12:e00586-21. [PMID: 33879584 PMCID: PMC8092256 DOI: 10.1128/mbio.00586-21] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 03/17/2021] [Indexed: 12/27/2022] Open
Abstract
The human commensal and opportunistic fungal pathogen Candida albicans displays extensive genetic and phenotypic variation across clinical isolates. Here, we performed RNA sequencing on 21 well-characterized isolates to examine how genetic variation contributes to gene expression differences and to link these differences to phenotypic traits. C. albicans adapts primarily through clonal evolution, and yet hierarchical clustering of gene expression profiles in this set of isolates did not reproduce their phylogenetic relationship. Strikingly, strain-specific gene expression was prevalent in some strain backgrounds. Association of gene expression with phenotypic data by differential analysis, linear correlation, and assembly of gene networks connected both previously characterized and novel genes with 23 C. albicans traits. Construction of de novo gene modules produced a gene atlas incorporating 67% of C. albicans genes and revealed correlations between expression modules and important phenotypes such as systemic virulence. Furthermore, targeted investigation of two modules that have novel roles in growth and filamentation supported our bioinformatic predictions. Together, these studies reveal widespread transcriptional variation across C. albicans isolates and identify genetic and epigenetic links to phenotypic variation based on coexpression network analysis.IMPORTANCE Infectious fungal species are often treated uniformly despite clear evidence of genotypic and phenotypic heterogeneity being widespread across strains. Identifying the genetic basis for this phenotypic diversity is extremely challenging because of the tens or hundreds of thousands of variants that may distinguish two strains. Here, we use transcriptional profiling to determine differences in gene expression that can be linked to phenotypic variation among a set of 21 Candida albicans isolates. Analysis of this transcriptional data set uncovered clear trends in gene expression characteristics for this species and new genes and pathways that were associated with variation in pathogenic processes. Direct investigation confirmed functional predictions for a number of new regulators associated with growth and filamentation, demonstrating the utility of these approaches in linking genes to important phenotypes.
Collapse
Affiliation(s)
- Joshua M Wang
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
| | - Andrew L Woodruff
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
| | - Matthew J Dunn
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
| | - Robert J Fillinger
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
| | - Richard J Bennett
- Department of Molecular Microbiology and Immunology, Brown University, Providence, Rhode Island, USA
| | - Matthew Z Anderson
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio, USA
| |
Collapse
|
32
|
Liboro K, Yu SR, Lim J, So YS, Bahn YS, Eoh H, Park H. Transcriptomic and Metabolomic Analysis Revealed Roles of Yck2 in Carbon Metabolism and Morphogenesis of Candida albicans. Front Cell Infect Microbiol 2021; 11:636834. [PMID: 33796481 PMCID: PMC8008151 DOI: 10.3389/fcimb.2021.636834] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 02/08/2021] [Indexed: 12/05/2022] Open
Abstract
Candida albicans is a part of the normal microbiome of human mucosa and is able to thrive in a wide range of host environments. As an opportunistic pathogen, the virulence of C. albicans is tied to its ability to switch between yeast and hyphal morphologies in response to various environmental cues, one of which includes nutrient availability. Thus, metabolic flexibility plays an important role in the virulence of the pathogen. Our previous study has shown that C. albicans Yeast Casein Kinase 2 (CaYck2) regulates the yeast-to-hyphal switch, but its regulatory mechanisms remain unknown. This study further elucidated the role of Yck2 in governing morphology and carbon metabolism by analyzing the transcriptome and metabolome of the C. albicans YCK2 deletion mutant strain (yck2Δ strain) in comparison to the wild type strain. Our study revealed that loss of CaYck2 perturbs carbon metabolism, leading to a transcriptional response that resembles a transcriptional response to glucose starvation with coinciding intracellular accumulation of glucose and depletion of TCA cycle metabolites. This shift in the metabolome is likely mediated by derepression of glucose-repressed genes in the Mig1/2-mediated glucose sensing pathway and by downregulation of glycolytic genes, possibly through the Rgt1-mediated SRR pathway. In addition, genes involved in beta-oxidation, glyoxylate cycle, oxidative stress response, and arginine biosynthesis were upregulated in the yck2Δ strain, which is highly reminiscent of C. albicans engulfment by macrophages. This coincides with an increase in arginine degradation intermediates in the yck2Δ strain, suggesting arginine catabolism as a potential mechanism of CaYck2-mediated filamentation as seen during C. albicans escape from macrophages. Transcriptome analysis also shows differential expression of hyphal transcriptional regulators Nrg1 and Ume6. This suggests dysregulation of hyphal initiation and elongation in the yck2Δ strain which may lead to the constitutive pseudohyphal phenotype of this strain. Metabolome analysis also detected a high abundance of methyl citrate cycle intermediates in the yck2Δ strain, suggesting the importance of CaYck2 in this pathway. Taken together, we discovered that CaYck2 is an integral piece of carbon metabolism and morphogenesis of C. albicans.
Collapse
Affiliation(s)
- Karl Liboro
- Department of Biological Sciences, California State University, Los Angeles, CA, United States
| | - Seong-Ryong Yu
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Juhyeon Lim
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
| | - Yee-Seul So
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Yong-Sun Bahn
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Hyungjin Eoh
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
| | - Hyunsook Park
- Department of Biological Sciences, California State University, Los Angeles, CA, United States
| |
Collapse
|
33
|
Abstract
In the last decades, Candida albicans has served as the leading causal agent of life-threatening invasive infections with mortality rates approaching 40% despite treatment. Candida albicans (C. albicans) exists in three biological phases: yeast, pseudohyphae, and hyphae. Hyphae, which represent an important phase in the disease process, can cause tissue damage by invading mucosal epithelial cells then leading to blood infection. In this review, we summarized recent results from different fields of fungal cell biology that are instrumental in understanding hyphal growth. This includes research on the differences among C. albicans phases; the regulatory mechanism of hyphal growth, extension, and maintaining cutting-edge polarity; cross regulations of hyphal development and the virulence factors that cause serious infection. With a better understanding of the mechanism on mycelium formation, this review provides a theoretical basis for the identification of targets in candidiasis treatment. It also gives some reference to the study of antifungal drugs.
Collapse
Affiliation(s)
- Hui Chen
- State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, China.,Department of Operative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xuedong Zhou
- State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, China.,Department of Operative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Biao Ren
- State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, China
| | - Lei Cheng
- State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, China.,Department of Operative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| |
Collapse
|
34
|
Ke CL, Liao YT, Lin CH. MSS2 maintains mitochondrial function and is required for chitosan resistance, invasive growth, biofilm formation and virulence in Candida albicans. Virulence 2021; 12:281-297. [PMID: 33427576 PMCID: PMC7808435 DOI: 10.1080/21505594.2020.1870082] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Candida albicans is the most prevalent fungal pathogen in humans, particularly in immunocompromised patients. In this study, by screening a C. albicans mutant library, we first identified that the MSS2 gene, an ortholog of Saccharomyces cerevisiae MSS2 required for mitochondrial respiration, mediates chitosan resistance. Upon treatment with 0.2% chitosan, the growth of mss2Δ strains was strikingly impaired, and MSS2 expression was significantly repressed by chitosan. Furthermore, mss2Δ strains exhibited slow growth on medium supplemented with glycerol as the sole carbon source. Similar to the chitosan-treated wild-type strain, the mss2Δ strain exhibited a significantly impaired ATP production ability. These data suggest that an antifungal mechanism of chitosan against C. albicans acts by inhibiting MSS2 gene expression, leading to repression of mitochondrial function. Normal respiratory function is suggested to be required for fungal virulence. Interestingly, the mss2Δ mutant strains exhibited significantly impaired invasive ability in vitro and ex vivo but retained normal hyphal development ability in liquid medium. Furthermore, the MSS2 deletion strains could not form robust biofilms and exhibited significantly reduced virulence. Collectively, these results demonstrated that the antifungal effect of chitosan against C. albicans is mediated via inhibition of mitochondrial biogenesis. These data may provide another strategy for antifungal drug development via inhibition of fungal mitochondria.
Collapse
Affiliation(s)
- Cai-Ling Ke
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University , Taipei, Taiwan
| | - Yu-Ting Liao
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University , Taipei, Taiwan
| | - Ching-Hsuan Lin
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University , Taipei, Taiwan
| |
Collapse
|
35
|
Li Y, Shan M, Zhu Y, Yao H, Li H, Gu B, Zhu Z. Kalopanaxsaponin A induces reactive oxygen species mediated mitochondrial dysfunction and cell membrane destruction in Candida albicans. PLoS One 2020; 15:e0243066. [PMID: 33253287 PMCID: PMC7703927 DOI: 10.1371/journal.pone.0243066] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Accepted: 11/14/2020] [Indexed: 01/24/2023] Open
Abstract
Candidiasis causes high morbidity and mortality among immunocompromised patients. Antifungal drug resistance and cytotoxicity highlight the need of effective antifungal therapeutics. In this study, we found that kalopanaxsaponin A (KPA), a triterpenoid saponin natural product, could inhibit the proliferation of various Candida species, and exerted a fungicidal effect against C. albicans. To further explore its antifungal action mode, spectrofluorophotometer, fluorescence microscopy and transmission electron microscopy were performed, showing that KPA treatment induced the accumulation of intracellular reactive oxygen species (ROS), resulting in mitochondrial dysfunction. Meanwhile, KPA treatment also broke down the membrane barrier of C. albicans causing the leakage of intracellular trehalose, the entrance of extracellular impermeable substance and the decrease of ergosterol content. Both ROS accumulation and membrane destruction contributed to the death of C. albicans cells. Our work preliminarily elucidated the potential mechanisms of KPA against C. albicans on a cellular level, and might provide a potential option for the treatment of clinical candidiasis.
Collapse
Affiliation(s)
- Ying Li
- Xuzhou Key Laboratory of Laboratory Diagnostics, School of Medical Technology, Xuzhou Medical University, Xuzhou, China
| | - Mingzhu Shan
- Xuzhou Key Laboratory of Laboratory Diagnostics, School of Medical Technology, Xuzhou Medical University, Xuzhou, China
| | - Yao Zhu
- Department of Genetics, Xuzhou Medical University, Xuzhou, China
| | - Huankai Yao
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Clinical Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Hongchun Li
- Xuzhou Key Laboratory of Laboratory Diagnostics, School of Medical Technology, Xuzhou Medical University, Xuzhou, China
- Department of Laboratory Medicine, Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Bing Gu
- Xuzhou Key Laboratory of Laboratory Diagnostics, School of Medical Technology, Xuzhou Medical University, Xuzhou, China
- Department of Laboratory Medicine, Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Zuobin Zhu
- Department of Genetics, Xuzhou Medical University, Xuzhou, China
- * E-mail:
| |
Collapse
|
36
|
Grainha T, Jorge P, Alves D, Lopes SP, Pereira MO. Unraveling Pseudomonas aeruginosa and Candida albicans Communication in Coinfection Scenarios: Insights Through Network Analysis. Front Cell Infect Microbiol 2020; 10:550505. [PMID: 33262953 PMCID: PMC7686562 DOI: 10.3389/fcimb.2020.550505] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 10/12/2020] [Indexed: 12/19/2022] Open
Abstract
Modern medicine is currently facing huge setbacks concerning infection therapeutics as microorganisms are consistently knocking down every antimicrobial wall set before them. The situation becomes more worrying when taking into account that, in both environmental and disease scenarios, microorganisms present themselves as biofilm communities that are often polymicrobial. This comprises a competitive advantage, with interactions between different species altering host responses, antimicrobial effectiveness, microbial pathogenesis and virulence, usually augmenting the severity of the infection and contributing for the recalcitrance towards conventional therapy. Pseudomonas aeruginosa and Candida albicans are two opportunistic pathogens often co-isolated from infections, mainly from mucosal tissues like the lung. Despite the billions of years of co-existence, this pair of microorganisms is a great example on how little is known about cross-kingdom interactions, particularly within the context of coinfections. Given the described scenario, this study aimed to collect, curate, and analyze all published experimental information on the molecular basis of P. aeruginosa and C. albicans interactions in biofilms, in order to shed light into key mechanisms that may affect infection prognosis, increasing this area of knowledge. Publications were optimally retrieved from PubMed and Web of Science and classified as to their relevance. Data was then systematically and manually curated, analyzed, and further reconstructed as networks. A total of 641 interactions between the two pathogens were annotated, outputting knowledge on important molecular players affecting key virulence mechanisms, such as hyphal growth, and related genes and proteins, constituting potential therapeutic targets for infections related to these bacterial-fungal consortia. Contrasting interactions were also analyzed, and quorum-sensing inhibition approaches were highlighted. All annotated data was made publicly available at www.ceb.uminho.pt/ISCTD, a database already containing similar data for P. aeruginosa and Staphylococcus aureus communication. This will allow researchers to cut on time and effort when studying this particular subject, facilitating the understanding of the basis of the inter-species and inter-kingdom interactions and how it can be modulated to help design alternative and more effective tailored therapies. Finally, data deposition will serve as base for future dataset integration, whose analysis will hopefully give insights into communications in more complex and varied biofilm communities.
Collapse
Affiliation(s)
- Tânia Grainha
- CEB-Centre of Biological Engineering, LIBRO-Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Campus de Gualtar, Braga, Portugal
| | - Paula Jorge
- CEB-Centre of Biological Engineering, LIBRO-Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Campus de Gualtar, Braga, Portugal
| | - Diana Alves
- CEB-Centre of Biological Engineering, LIBRO-Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Campus de Gualtar, Braga, Portugal
| | - Susana Patrícia Lopes
- CEB-Centre of Biological Engineering, LIBRO-Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Campus de Gualtar, Braga, Portugal
| | - Maria Olívia Pereira
- CEB-Centre of Biological Engineering, LIBRO-Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Campus de Gualtar, Braga, Portugal
| |
Collapse
|
37
|
Song J, Zhou J, Zhang L, Li R. Mitochondria-Mediated Azole Drug Resistance and Fungal Pathogenicity: Opportunities for Therapeutic Development. Microorganisms 2020; 8:E1574. [PMID: 33066090 PMCID: PMC7600254 DOI: 10.3390/microorganisms8101574] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 10/09/2020] [Accepted: 10/09/2020] [Indexed: 12/16/2022] Open
Abstract
In recent years, the role of mitochondria in pathogenic fungi in terms of azole resistance and fungal pathogenicity has been a rapidly developing field. In this review, we describe the molecular mechanisms by which mitochondria are involved in regulating azole resistance and fungal pathogenicity. Mitochondrial function is involved in the regulation of drug efflux pumps at the transcriptional and posttranslational levels. On the one hand, defects in mitochondrial function can serve as the signal leading to activation of calcium signaling and the pleiotropic drug resistance pathway and, therefore, can globally upregulate the expression of drug efflux pump genes, leading to azole drug resistance. On the other hand, mitochondria also contribute to azole resistance through modulation of drug efflux pump localization and activity. Mitochondria further contribute to azole resistance through participating in iron homeostasis and lipid biosynthesis. Additionally, mitochondrial dynamics play an important role in azole resistance. Meanwhile, mitochondrial morphology is important for fungal virulence, playing roles in growth in stressful conditions in a host. Furthermore, there is a close link between mitochondrial respiration and fungal virulence, and mitochondrial respiration plays an important role in morphogenetic transition, hypoxia adaptation, and cell wall biosynthesis. Finally, we discuss the possibility for targeting mitochondrial factors for the development of antifungal therapies.
Collapse
Affiliation(s)
- Jinxing Song
- The Key Laboratory of Biotechnology for Medicinal Plants of Jiangsu Province and School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu 221116, China;
- Shandong Provincial Key Laboratory of Infection and Immunity, Jinan 250012, China;
| | - Jingwen Zhou
- The Key Laboratory of Biotechnology for Medicinal Plants of Jiangsu Province and School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu 221116, China;
| | - Lei Zhang
- Shandong Provincial Key Laboratory of Infection and Immunity, Jinan 250012, China;
| | - Rongpeng Li
- The Key Laboratory of Biotechnology for Medicinal Plants of Jiangsu Province and School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu 221116, China;
| |
Collapse
|
38
|
Truong T, Pang LM, Rajan S, Wong SSW, Fung YME, Samaranayake L, Seneviratne CJ. The Proteome of Community Living Candida albicans Is Differentially Modulated by the Morphologic and Structural Features of the Bacterial Cohabitants. Microorganisms 2020; 8:microorganisms8101541. [PMID: 33036329 PMCID: PMC7601143 DOI: 10.3390/microorganisms8101541] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 10/02/2020] [Accepted: 10/03/2020] [Indexed: 11/16/2022] Open
Abstract
Candida albicans is a commensal polymorphic and opportunistic fungus, which usually resides as a small community in the oral cavities of a majority of humans. The latter eco-system presents this yeast varied opportunities for mutualistic interactions with other cohabitant oral bacteria, that synergizes its persistence and pathogenicity. Collectively, these communities live within complex plaque biofilms which may adversely affect the oral health and increase the proclivity for oral candidiasis. The proteome of such oral biofilms with myriad interkingdom interactions are largely underexplored. Herein, we employed limma differential expression analysis, and cluster analysis to explore the proteomic interactions of C. albicans biofilms with nine different common oral bacterial species, Aggregatibacter actinomycetemcomitans, Actinomyces naeslundii, Fusobacterium nucleatum, Enterococcus faecalis, Porphyromonas gingivalis, Streptococcus mutants, Streptococcus sanguinis, Streptococcus mitis, and Streptococcus sobrinus. Interestingly, upon exposure of C. albicans biofilms to the foregoing heat-killed bacteria, the proteomes of the fungus associated with cellular respiration, translation, oxidoreductase activity, and ligase activity were significantly altered. Subsequent differential expression and cluster analysis revealed the subtle, yet significant alterations in the C. albicans proteome, particularly on exposure to bacteria with dissimilar cell morphologies, and Gram staining characteristics.
Collapse
Affiliation(s)
- Thuyen Truong
- Oral Sciences, Faculty of Dentistry, National University of Singapore, Singapore 119085, Singapore;
| | - Li Mei Pang
- National Dental Research Institute Singapore (NDRIS), National Dental Centre Singapore, Singapore 168938, Singapore;
| | - Suhasini Rajan
- Walther Straub Institute of Pharmacology and Toxicology, Member of the German Center for Lung Research (DZL), Medical Faculty, LMU-Munich, 80336 Munich, Germany;
| | - Sarah Sze Wah Wong
- Molecular Mycology Unit, Institut Pasteur, CNRS, UMR2000, 10098 Paris, France;
| | - Yi Man Eva Fung
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China;
| | - Lakshman Samaranayake
- College of Dental Medicine, University of Sharjah, Sharjah 27272, UAE;
- Faculty of Dentistry, The University of Hong Kong, Hong Kong, China
| | - Chaminda Jayampath Seneviratne
- National Dental Research Institute Singapore (NDRIS), National Dental Centre Singapore, Singapore 168938, Singapore;
- Oral Health Academic Clinical Programme, Duke-NUS Medical School, Singapore 169857, Singapore
- Correspondence: ; Tel.: +65-65767141
| |
Collapse
|
39
|
Conditional antagonism in co-cultures of Pseudomonas aeruginosa and Candida albicans: An intersection of ethanol and phosphate signaling distilled from dual-seq transcriptomics. PLoS Genet 2020; 16:e1008783. [PMID: 32813693 PMCID: PMC7480860 DOI: 10.1371/journal.pgen.1008783] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 09/09/2020] [Accepted: 06/20/2020] [Indexed: 12/12/2022] Open
Abstract
Pseudomonas aeruginosa and Candida albicans are opportunistic pathogens whose interactions involve the secreted products ethanol and phenazines. Here, we describe the role of ethanol in mixed-species co-cultures by dual-seq analyses. P. aeruginosa and C. albicans transcriptomes were assessed after growth in mono-culture or co-culture with either ethanol-producing C. albicans or a C. albicans mutant lacking the primary ethanol dehydrogenase, Adh1. Analysis of the RNA-Seq data using KEGG pathway enrichment and eADAGE methods revealed several P. aeruginosa responses to C. albicans-produced ethanol including the induction of a non-canonical low-phosphate response regulated by PhoB. C. albicans wild type, but not C. albicans adh1Δ/Δ, induces P. aeruginosa production of 5-methyl-phenazine-1-carboxylic acid (5-MPCA), which forms a red derivative within fungal cells and exhibits antifungal activity. Here, we show that C. albicans adh1Δ/Δ no longer activates P. aeruginosa PhoB and PhoB-regulated phosphatase activity, that exogenous ethanol complements this defect, and that ethanol is sufficient to activate PhoB in single-species P. aeruginosa cultures at permissive phosphate levels. The intersection of ethanol and phosphate in co-culture is inversely reflected in C. albicans; C. albicans adh1Δ/Δ had increased expression of genes regulated by Pho4, the C. albicans transcription factor that responds to low phosphate, and Pho4-dependent phosphatase activity. Together, these results show that C. albicans-produced ethanol stimulates P. aeruginosa PhoB activity and 5-MPCA-mediated antagonism, and that both responses are dependent on local phosphate concentrations. Further, our data suggest that phosphate scavenging by one species improves phosphate access for the other, thus highlighting the complex dynamics at play in microbial communities. Pseudomonas aeruginosa and Candida albicans are opportunistic pathogens that are frequently isolated from co-infections. Using a combination of dual-seq transcriptomics and genetics approaches, we found that ethanol produced by C. albicans stimulates the PhoB regulon in P. aeruginosa asynchronously with activation of the Pho4 regulon in C. albicans. We validated our result by showing that PhoB plays multiple roles in co-culture including orchestrating the competition for phosphate and the production of 5-methyl-phenazine-1-carboxylic acid; the P. aeruginosa phenazine response to C. albicans-produced ethanol depends on phosphate availability. The conditional stimulation of antifungal production in response to sub-inhibitory concentrations of ethanol only under phosphate limitation highlights the importance of considering nutrient concentrations in the analysis of co-culture interactions and suggests that the low-phosphate response in one species influences phosphate availability for the other.
Collapse
|
40
|
Affiliation(s)
- Philipp Brandt
- Septomics Research Center, Friedrich Schiller University and Leibniz Institute for Natural Product Research and Infection Biology–Hans Knöll Institute, Jena, Germany
| | - Enrico Garbe
- Septomics Research Center, Friedrich Schiller University and Leibniz Institute for Natural Product Research and Infection Biology–Hans Knöll Institute, Jena, Germany
| | - Slavena Vylkova
- Septomics Research Center, Friedrich Schiller University and Leibniz Institute for Natural Product Research and Infection Biology–Hans Knöll Institute, Jena, Germany
| |
Collapse
|
41
|
Moonlighting Proteins at the Candidal Cell Surface. Microorganisms 2020; 8:microorganisms8071046. [PMID: 32674422 PMCID: PMC7409194 DOI: 10.3390/microorganisms8071046] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/11/2020] [Accepted: 07/12/2020] [Indexed: 12/31/2022] Open
Abstract
The cell wall in Candida albicans is not only a tight protective envelope but also a point of contact with the human host that provides a dynamic response to the constantly changing environment in infection niches. Particularly important roles are attributed to proteins exposed at the fungal cell surface. These include proteins that are stably and covalently bound to the cell wall or cell membrane and those that are more loosely attached. Interestingly in this regard, numerous loosely attached proteins belong to the class of “moonlighting proteins” that are originally intracellular and that perform essentially different functions in addition to their primary housekeeping roles. These proteins also demonstrate unpredicted interactions with non-canonical partners at an a priori unexpected extracellular location, achieved via non-classical secretion routes. Acting both individually and collectively, the moonlighting proteins contribute to candidal virulence and pathogenicity through their involvement in mechanisms critical for successful host colonization and infection, such as the adhesion to host cells, interactions with plasma homeostatic proteolytic cascades, responses to stress conditions and molecular mimicry. The documented knowledge of the roles of these proteins in C. albicans pathogenicity has utility for assisting the design of new therapeutic, diagnostic and preventive strategies against candidiasis.
Collapse
|
42
|
Sho1p Connects Glycolysis to Ras1-cAMP Signaling and Is Required for Microcolony Formation in Candida albicans. mSphere 2020; 5:5/4/e00366-20. [PMID: 32641426 PMCID: PMC7343979 DOI: 10.1128/msphere.00366-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
C. albicans microcolonies form extensive hyphal structures that enhance surface adherence and penetrate underlying tissues to promote fungal infections. This study examined the environmental conditions that promote microcolony formation and how these signals are relayed, in order to disrupt signaling and reduce pathogenesis. We found that a membrane-localized protein, Sho1, is an upstream regulator of glycolysis and required for Ras1-cAMP signaling. Sho1 controlled the Ras1-dependent expression of core microcolony genes involved in adhesion and virulence. This new regulatory function for Sho1 linking glycolysis to microcolony formation reveals a novel role for this fungal membrane protein. Candida albicans is an opportunistic, dimorphic fungus that causes candidiasis in immunocompromised people. C. albicans forms specialized structures called microcolonies that are important for surface adhesion and virulence. Microcolonies form in response to specific environmental conditions and require glycolytic substrates for optimal growth. However, fungal signaling pathways involved in sensing and transmitting these environmental cues to induce microcolony formation have not been identified. Here, we show that the C. albicans Ras1-cAMP cascade is required for microcolony formation, while the Cek1-MAP kinase pathway is not required, and Hog1 represses microcolony formation. The membrane protein Sho1, known to regulate the Cek1 pathway in yeasts, was indispensable for C. albicans microcolony formation but regulated the Ras1-cAMP pathway instead, based upon diminished intracellular levels of cAMP and reduced expression of core microcolony genes, including HWP1, PGA10, and ECE1, in C. albicanssho1Δ cells. Based upon predicted physical interactions between Sho1 and the glycolytic enzymes Pfk1, Fba1, Pgk1, and Cdc19, we hypothesized that Sho1 regulates Ras1-cAMP by establishing cellular energy levels produced by glycolysis. Indeed, microcolony formation was restored in C. albicanssho1Δ cells by addition of exogenous intermediates of glycolysis, including downstream products of each predicted interacting enzyme (fructose 1,6 bisphosphate, glyceraldehyde phosphate, 3-phosphoglyceric acid, and pyruvate). Thus, C. albicans Sho1 is an upstream regulator of the Ras1-cAMP signaling pathway that connects glycolytic metabolism to the formation of pathogenic microcolonies. IMPORTANCEC. albicans microcolonies form extensive hyphal structures that enhance surface adherence and penetrate underlying tissues to promote fungal infections. This study examined the environmental conditions that promote microcolony formation and how these signals are relayed, in order to disrupt signaling and reduce pathogenesis. We found that a membrane-localized protein, Sho1, is an upstream regulator of glycolysis and required for Ras1-cAMP signaling. Sho1 controlled the Ras1-dependent expression of core microcolony genes involved in adhesion and virulence. This new regulatory function for Sho1 linking glycolysis to microcolony formation reveals a novel role for this fungal membrane protein.
Collapse
|
43
|
Tripathi A, Liverani E, Tsygankov AY, Puri S. Iron alters the cell wall composition and intracellular lactate to affect Candida albicans susceptibility to antifungals and host immune response. J Biol Chem 2020; 295:10032-10044. [PMID: 32503842 DOI: 10.1074/jbc.ra120.013413] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 05/27/2020] [Indexed: 12/19/2022] Open
Abstract
Fungal pathogen Candida albicans has a complex cell wall consisting of an outer layer of mannans and an inner layer of β-glucans and chitin. The fungal cell wall is the primary target for antifungals and is recognized by host immune cells. Environmental conditions such as carbon sources, pH, temperature, and oxygen tension can modulate the fungal cell wall architecture. Cellular signaling pathways, including the mitogen-activated protein kinase (MAPK) pathways, are responsible for sensing environmental cues and mediating cell wall alterations. Although iron has recently been shown to affect β-1,3-glucan exposure on the cell wall, we report here that iron changes the composition of all major C. albicans cell wall components. Specifically, high iron decreased the levels of mannans (including phosphomannans) and chitin; and increased β-1,3-glucan levels. These changes increased the resistance of C. albicans to cell wall-perturbing antifungals. Moreover, high iron cells exhibited adequate mitochondrial functioning; leading to a reduction in accumulation of lactate that signals through the transcription factor Crz1 to induce β-1,3-glucan masking in C. albicans We show here that iron-induced changes in β-1,3-glucan exposure are lactate-dependent; and high iron causes β-1,3-glucan exposure by preventing lactate-induced, Crz1-mediated inhibition of activation of the fungal MAPK Cek1. Furthermore, despite exhibiting enhanced antifungal resistance, high iron C. albicans cells had reduced survival upon phagocytosis by macrophages. Our results underscore the role of iron as an environmental signal in multiple signaling pathways that alter cell wall architecture in C. albicans, thereby affecting its survival upon exposure to antifungals and host immune response.
Collapse
Affiliation(s)
- Aparna Tripathi
- Oral Microbiome Research Laboratory, Department of Oral Health Sciences, Kornberg School of Dentistry, Temple University, Philadelphia, Pennsylvania, USA
| | - Elisabetta Liverani
- Sol Sherry Thrombosis Research Center, Temple University School of Medicine, Temple University Hospital, Philadelphia, Pennsylvania, USA
| | - Alexander Y Tsygankov
- Sol Sherry Thrombosis Research Center, Temple University School of Medicine, Temple University Hospital, Philadelphia, Pennsylvania, USA.,Department of Microbiology and Immunology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA
| | - Sumant Puri
- Oral Microbiome Research Laboratory, Department of Oral Health Sciences, Kornberg School of Dentistry, Temple University, Philadelphia, Pennsylvania, USA
| |
Collapse
|
44
|
Shen M, Li PT, Wu YJ, Lin CH, Chai E, Chang TC, Chen CT. The antifungal activities and biological consequences of BMVC-12C-P, a carbazole derivative against Candida species. Med Mycol 2020; 58:521-529. [PMID: 31281934 DOI: 10.1093/mmy/myz071] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 05/19/2019] [Accepted: 06/05/2019] [Indexed: 11/14/2022] Open
Abstract
Fungal infections, particularly Candida species, have increased worldwide and caused high morbidity and mortality rates. The toxicity and development of resistance in present antifungal drugs justify the need of new drugs with different mechanism of action. BMVC-12C-P, a carbazole-type compound, has been found to dysfunction mitochondria. BMVC-12C-P displayed the strongest antifungal activities among all of the BMVC derivatives. The minimal inhibitory concentration (MIC) of BMVC-12C-P against Candida species ranged from 1 to 2 μg/ml. Fluconazole-resistant clinical isolates of Candida species were highly susceptible to BMVC-12C-P. The potent fungicidal activity of BMVC-12C-P relates to its impairing mitochondrial function. Furthermore, we found that the hyphae growth and biofilm formation were suppressed in C. albicans survived from BMVC-12C-P treatment. This study demonstrates the potential of BMVC-12C-P as an antifungal agent for treating Candida infections.
Collapse
Affiliation(s)
- Mandy Shen
- Department of Biochemical Science and Technology, National Taiwan University, Taipei 10617, Taiwan
| | - Pei-Tzu Li
- Department of Biochemical Science and Technology, National Taiwan University, Taipei 10617, Taiwan
| | - Yan-Jia Wu
- Department of Biochemical Science and Technology, National Taiwan University, Taipei 10617, Taiwan
| | - Ching-Hsuan Lin
- Department of Biochemical Science and Technology, National Taiwan University, Taipei 10617, Taiwan
| | - Eric Chai
- Department of Biochemical Science and Technology, National Taiwan University, Taipei 10617, Taiwan
| | - Ta-Chau Chang
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
| | - Chin-Tin Chen
- Department of Biochemical Science and Technology, National Taiwan University, Taipei 10617, Taiwan
| |
Collapse
|
45
|
Wang Q, Verma J, Vidan N, Wang Y, Tucey TM, Lo TL, Harrison PF, See M, Swaminathan A, Kuchler K, Tscherner M, Song J, Powell DR, Sopta M, Beilharz TH, Traven A. The YEATS Domain Histone Crotonylation Readers Control Virulence-Related Biology of a Major Human Pathogen. Cell Rep 2020; 31:107528. [PMID: 32320659 DOI: 10.1016/j.celrep.2020.107528] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 01/31/2020] [Accepted: 03/27/2020] [Indexed: 12/13/2022] Open
Abstract
Identification of multiple histone acylations diversifies transcriptional control by metabolism, but their functions are incompletely defined. Here we report evidence of histone crotonylation in the human fungal pathogen Candida albicans. We define the enzymes that regulate crotonylation and show its dynamic control by environmental signals: carbon sources, the short-chain fatty acids butyrate and crotonate, and cell wall stress. Crotonate regulates stress-responsive transcription and rescues C. albicans from cell wall stress, indicating broad impact on cell biology. The YEATS domain crotonylation readers Taf14 and Yaf9 are required for C. albicans virulence, and Taf14 controls gene expression, stress resistance, and invasive growth via its chromatin reader function. Blocking the Taf14 C terminus with a tag reduced virulence, suggesting that inhibiting Taf14 interactions with chromatin regulators impairs function. Our findings shed light on the regulation of histone crotonylation and the functions of the YEATS proteins in eukaryotic pathogen biology and fungal infections.
Collapse
Affiliation(s)
- Qi Wang
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800 VIC, Australia
| | - Jiyoti Verma
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800 VIC, Australia
| | - Nikolina Vidan
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800 VIC, Australia; Department of Molecular Biology, Rudjer Boskovic Institute, Bijenicka 54, 10000 Zagreb, Croatia
| | - Yanan Wang
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800 VIC, Australia
| | - Timothy M Tucey
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800 VIC, Australia
| | - Tricia L Lo
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800 VIC, Australia
| | - Paul F Harrison
- Bioinformatics Platform, Monash University, Clayton 3800 VIC, Australia
| | - Michael See
- Bioinformatics Platform, Monash University, Clayton 3800 VIC, Australia
| | - Angavai Swaminathan
- Development and Stem Cells Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800 VIC, Australia
| | - Karl Kuchler
- Medical University of Vienna, Center for Medical Biochemistry, Max Perutz Labs, Campus Vienna Biocenter, Dr. Bohr-Gasse 9/2, Vienna, Austria
| | - Michael Tscherner
- Medical University of Vienna, Center for Medical Biochemistry, Max Perutz Labs, Campus Vienna Biocenter, Dr. Bohr-Gasse 9/2, Vienna, Austria
| | - Jiangning Song
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800 VIC, Australia
| | - David R Powell
- Bioinformatics Platform, Monash University, Clayton 3800 VIC, Australia
| | - Mary Sopta
- Department of Molecular Biology, Rudjer Boskovic Institute, Bijenicka 54, 10000 Zagreb, Croatia
| | - Traude H Beilharz
- Development and Stem Cells Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800 VIC, Australia
| | - Ana Traven
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800 VIC, Australia.
| |
Collapse
|
46
|
Inhibition of Respiration of Candida albicans by Small Molecules Increases Phagocytosis Efficacy by Macrophages. mSphere 2020; 5:5/2/e00016-20. [PMID: 32295866 PMCID: PMC7160677 DOI: 10.1128/msphere.00016-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Candida albicans adapts to various conditions in different body niches by regulating gene expression, protein synthesis, and metabolic pathways. These adaptive reactions not only allow survival but also influence the interaction with host cells, which is governed by the composition and structure of the fungal cell wall. Numerous studies had shown linkages between mitochondrial functionality, cell wall integrity and structure, and pathogenicity. Thus, we decided to inhibit single complexes of the respiratory chain of C. albicans and to analyze the resultant interaction with macrophages via their phagocytic activity. Remarkably, inhibition of the fungal bc1 complex by antimycin A increased phagocytosis, which correlated with an increased accessibility of β-glucans. To contribute to mechanistic insights, we performed metabolic studies, which highlighted significant changes in the abundance of constituents of the plasma membrane. Collectively, our results reinforce the strong linkage between fungal energy metabolism and other components of fungal physiology, which also determine the vulnerability to immune defense reactions.IMPORTANCE The yeast Candida albicans is one of the major fungal human pathogens, for which new therapeutic approaches are required. We aimed at enhancements of the phagocytosis efficacy of macrophages by targeting the cell wall structure of C. albicans, as the coverage of the β-glucan layer by mannans is one of the immune escape mechanisms of the fungus. We unambiguously show that inhibition of the fungal bc1 complex correlates with increased accessibilities of β-glucans and improved phagocytosis efficiency. Metabolic studies proved not only the known direct effects on reactive oxygen species (ROS) production and fermentative pathways but also the clear downregulation of the ergosterol pathway and upregulation of unsaturated fatty acids. The changed composition of the plasma membrane could also influence the interaction with the overlying cell wall. Thus, our work highlights the far-reaching relevance of energy metabolism, indirectly also for host-pathogen interactions, without affecting viability.
Collapse
|
47
|
Tian F, Lee SY, Woo SY, Chun HS. Alternative Oxidase: A Potential Target for Controlling Aflatoxin Contamination and Propagation of Aspergillus flavus. Front Microbiol 2020; 11:419. [PMID: 32256475 PMCID: PMC7092633 DOI: 10.3389/fmicb.2020.00419] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 02/27/2020] [Indexed: 12/16/2022] Open
Abstract
Aflatoxins are among the most hazardous natural cereal contaminants. These mycotoxins are produced by Aspergillus spp. as polyketide secondary metabolites. Aflatoxigenic fungi including A. flavus express the alternative oxidase (AOX), which introduces a branch in the cytochrome-based electron transfer chain by coupling ubiquinol oxidation directly with the reduction of O2 to H2O. AOX is closely associated with fungal pathogenesis, morphogenesis, stress signaling, and drug resistance and, as recently reported, affects the production of mycotoxins such as sterigmatocystin, the penultimate intermediate in aflatoxin B1 biosynthesis. Thus, AOX might be considered a target for controlling the propagation of and aflatoxin contamination by A. flavus. Hence, this review summarizes the current understanding of fungal AOX and the alternative respiration pathway and the development and potential applications of AOX inhibitors. This review indicates that AOX inhibitors, either alone or in combination with current antifungal agents, are potentially applicable for developing novel, effective antifungal strategies. However, considering the conservation of AOX in fungal and plant cells, a deeper understanding of fungal alternative respiration and fungal AOX structure is needed, along with effective fungal-specific AOX inhibitors.
Collapse
Affiliation(s)
- Fei Tian
- Food Toxicology Laboratory, Advanced Food Safety Research Group, BK21 Plus, School of Food Science and Technology, Chung-Ang University, Anseong, South Korea
| | - Sang Yoo Lee
- Food Toxicology Laboratory, Advanced Food Safety Research Group, BK21 Plus, School of Food Science and Technology, Chung-Ang University, Anseong, South Korea
| | - So Young Woo
- Food Toxicology Laboratory, Advanced Food Safety Research Group, BK21 Plus, School of Food Science and Technology, Chung-Ang University, Anseong, South Korea
| | - Hyang Sook Chun
- Food Toxicology Laboratory, Advanced Food Safety Research Group, BK21 Plus, School of Food Science and Technology, Chung-Ang University, Anseong, South Korea
| |
Collapse
|
48
|
Phosphoric Metabolites Link Phosphate Import and Polysaccharide Biosynthesis for Candida albicans Cell Wall Maintenance. mBio 2020; 11:mBio.03225-19. [PMID: 32184254 PMCID: PMC7078483 DOI: 10.1128/mbio.03225-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Candida species cause hundreds of thousands of invasive infections with high mortality each year. Developing novel antifungal agents is challenging due to the many similarities between fungal and human cells. Maintaining phosphate balance is essential for all organisms but is achieved completely differently by fungi and humans. A protein that imports phosphate into fungal cells, Pho84, is not present in humans and is required for normal cell wall stress resistance and cell wall integrity signaling in C. albicans. Nucleotide sugars, which are phosphate-containing building block molecules for construction of the cell wall, are diminished in cells lacking Pho84. Cell wall-constructing enzymes may be slowed by lack of these building blocks, in addition to being inhibited by drugs. Combined targeting of Pho84 and cell wall-constructing enzymes may provide a strategy for antifungal therapy by which two sequential steps of cell wall maintenance are blocked for greater potency. The Candida albicans high-affinity phosphate transporter Pho84 is required for normal Target of Rapamycin (TOR) signaling, oxidative stress resistance, and virulence of this fungal pathogen. It also contributes to C. albicans’ tolerance of two antifungal drug classes, polyenes and echinocandins. Echinocandins inhibit biosynthesis of a major cell wall component, beta-1,3-glucan. Cells lacking Pho84 were hypersensitive to other forms of cell wall stress beyond echinocandin exposure, while their cell wall integrity signaling response was weak. Metabolomics experiments showed that levels of phosphoric intermediates, including nucleotides like ATP and nucleotide sugars, were low in pho84 mutant compared to wild-type cells recovering from phosphate starvation. Nonphosphoric precursors like nucleobases and nucleosides were elevated. Outer cell wall phosphomannan biosynthesis requires a nucleotide sugar, GDP-mannose. The nucleotide sugar UDP-glucose is the substrate of enzymes that synthesize two major structural cell wall polysaccharides, beta-1,3- and beta-1,6-glucan. Another nucleotide sugar, UDP-N-acetylglucosamine, is the substrate of chitin synthases which produce a stabilizing component of the intercellular septum and of lateral cell walls. Lack of Pho84 activity, and phosphate starvation, potentiated pharmacological or genetic perturbation of these enzymes. We posit that low substrate concentrations of beta-d-glucan- and chitin synthases, together with pharmacologic inhibition of their activity, diminish enzymatic reaction rates as well as the yield of their cell wall-stabilizing products. Phosphate import is not conserved between fungal and human cells, and humans do not synthesize beta-d-glucans or chitin. Hence, inhibiting these processes simultaneously could yield potent antifungal effects with low toxicity to humans.
Collapse
|
49
|
Cottier F, Hall RA. Face/Off: The Interchangeable Side of Candida Albicans. Front Cell Infect Microbiol 2020; 9:471. [PMID: 32047726 PMCID: PMC6997470 DOI: 10.3389/fcimb.2019.00471] [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: 09/09/2019] [Accepted: 12/20/2019] [Indexed: 12/20/2022] Open
Abstract
Due to limited mobility, fungi, like most unicellular organisms, have evolved mechanisms to adapt to sudden chemical and/or physical variation in their environment. Candida albicans is recognized as a model organism to study eukaryotic responses to environmental changes, as this human commensal yeast but also opportunistic pathogen responds to numerous environmental cues through switching morphologies from yeast to hyphae growth. This mechanism is largely controlled by two major pathways: cAMP-PKA and MAPK, but each environmental signal is sensed by specific sensors. However, morphological switching is not the only response C. albicans exerts in response to environmental cues. Recently, fungal cell wall remodeling in response to host-derived environmental cues has been identified as a way for C. albicans to manipulate the innate immune system. The fungal cell wall is composed of a chitin skeleton linked to a network of β-glucan, which anchors proteins and mannans to the fungal cell surface. As localized on the cell surface, these molecules drive interactions with the environment and other cells, particularly with host immune cells. C. albicans is recognized by immune cells such as neutrophils and macrophages via pathogen recognition receptors (PRRs) that bind different components of the cell wall. While β-glucan and mannan are proinflammatory molecules, chitin can induce anti-inflammatory responses. Interestingly, C. albicans is able to regulate the exposure of these pathogen-associated molecular patterns (PAMPs) according to environmental cues resulting in a modulation of the host immune response. This review describes the mechanisms involved in C. albicans response to environmental changes and their effect on immune recognition.
Collapse
Affiliation(s)
- Fabien Cottier
- School of Biosciences, Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Rebecca A Hall
- School of Biosciences, Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom.,Kent Fungal Group, School of Biosciences, University of Kent, Canterbury, United Kingdom
| |
Collapse
|
50
|
Koch B, Barugahare AA, Lo TL, Huang C, Schittenhelm RB, Powell DR, Beilharz TH, Traven A. A Metabolic Checkpoint for the Yeast-to-Hyphae Developmental Switch Regulated by Endogenous Nitric Oxide Signaling. Cell Rep 2019; 25:2244-2258.e7. [PMID: 30463019 DOI: 10.1016/j.celrep.2018.10.080] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 07/31/2018] [Accepted: 10/22/2018] [Indexed: 12/13/2022] Open
Abstract
The yeast Candida albicans colonizes several sites in the human body and responds to metabolic signals in commensal and pathogenic states. The yeast-to-hyphae transition correlates with virulence, but how metabolic status is integrated with this transition is incompletely understood. We used the putative mitochondrial fission inhibitor mdivi-1 to probe the crosstalk between hyphal signaling and metabolism. Mdivi-1 repressed C. albicans hyphal morphogenesis, but the mechanism was independent of its presumed target, the mitochondrial fission GTPase Dnm1. Instead, mdivi-1 triggered extensive metabolic reprogramming, consistent with metabolic stress, and reduced endogenous nitric oxide (NO) levels. Limiting endogenous NO stabilized the transcriptional repressor Nrg1 and inhibited the yeast-to-hyphae transition. We establish a role for endogenous NO signaling in C. albicans hyphal morphogenesis and suggest that NO regulates a metabolic checkpoint for hyphal growth. Furthermore, identifying NO signaling as an mdivi-1 target could inform its therapeutic applications in human diseases.
Collapse
Affiliation(s)
- Barbara Koch
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
| | - Adele A Barugahare
- Bioinformatics Platform, Monash University, Clayton, VIC 3800, Australia
| | - Tricia L Lo
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
| | - Cheng Huang
- Biomedical Proteomics Facility and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
| | - Ralf B Schittenhelm
- Biomedical Proteomics Facility and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
| | - David R Powell
- Bioinformatics Platform, Monash University, Clayton, VIC 3800, Australia
| | - Traude H Beilharz
- Development and Stem Cells Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
| | - Ana Traven
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia.
| |
Collapse
|