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Yoo K, Bhattacharya S, Oliveira NK, Pereira de Sa N, Matos GS, Del Poeta M, Fries BC. With age comes resilience: how mitochondrial modulation drives age-associated fluconazole tolerance in Cryptococcus neoformans. mBio 2024:e0184724. [PMID: 39136442 DOI: 10.1128/mbio.01847-24] [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: 07/02/2024] [Accepted: 07/09/2024] [Indexed: 08/21/2024] Open
Abstract
Cryptococcus neoformans (Cn) is an opportunistic fungal microorganism that causes life-threatening meningoencephalitis. During the infection, the microbial population is heterogeneously composed of cells with varying generational ages, with older cells accumulating during chronic infections. This is attributed to their enhanced resistance to phagocytic killing and tolerance of antifungals like fluconazole (FLC). In this study, we investigated the role of ergosterol synthesis, ATP-binding cassette (ABC) transporters, and mitochondrial metabolism in the regulation of age-dependent FLC tolerance. We find that old Cn cells increase the production of ergosterol and exhibit upregulation of ABC transporters. Old cells also show transcriptional and phenotypic characteristics consistent with increased metabolic activity, leading to increased ATP production. This is accompanied by increased production of reactive oxygen species, which results in mitochondrial fragmentation. This study demonstrates that the metabolic changes occurring in the mitochondria of old cells drive the increase in ergosterol synthesis and the upregulation of ABC transporters, leading to FLC tolerance. IMPORTANCE Infections caused by Cryptococcus neoformans cause more than 180,000 deaths annually. Estimated 1-year mortality for patients receiving care ranges from 20% in developed countries to 70% in developing countries, suggesting that current treatments are inadequate. Some fungal cells can persist and replicate despite the usage of current antifungal regimens, leading to death or treatment failure. Aging in fungi is associated with enhanced tolerance against antifungals and resistance to killing by host cells. This study shows that age-dependent increase in mitochondrial reactive oxygen species drive changes in the regulation of membrane transporters and ergosterol synthesis, ultimately leading to the heightened tolerance against fluconazole in old C. neoformans cells. Understanding the underlying molecular mechanisms of this age-associated antifungal tolerance will enable more targeted antifungal therapies for cryptococcal infections.
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Affiliation(s)
- Kyungyoon Yoo
- Department of Microbiology and Immunology, Renaissance School of Medicine, Stony Brook University, Stony Brook, New York, USA
| | - Somanon Bhattacharya
- Division of Infectious Diseases, Department of Medicine, Stony Brook University, Stony Brook, New York, USA
| | - Natalia Kronbauer Oliveira
- Department of Microbiology and Immunology, Renaissance School of Medicine, Stony Brook University, Stony Brook, New York, USA
| | - Nivea Pereira de Sa
- Department of Microbiology and Immunology, Renaissance School of Medicine, Stony Brook University, Stony Brook, New York, USA
| | - Gabriel Soares Matos
- Department of Microbiology and Immunology, Renaissance School of Medicine, Stony Brook University, Stony Brook, New York, USA
| | - Maurizio Del Poeta
- Department of Microbiology and Immunology, Renaissance School of Medicine, Stony Brook University, Stony Brook, New York, USA
- Division of Infectious Diseases, Department of Medicine, Stony Brook University, Stony Brook, New York, USA
- Veterans Administration Medical Center, Northport, New York, USA
- Institute of Chemical Biology and Drug Discovery, Stony Brook, New York, USA
| | - Bettina C Fries
- Department of Microbiology and Immunology, Renaissance School of Medicine, Stony Brook University, Stony Brook, New York, USA
- Division of Infectious Diseases, Department of Medicine, Stony Brook University, Stony Brook, New York, USA
- Veterans Administration Medical Center, Northport, New York, USA
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2
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Hu G, Qu X, Bhalla K, Xue P, Bakkeren E, Lee CWJ, Kronstad JW. Loss of the putative Rab GTPase, Ypt7, impairs the virulence of Cryptococcus neoformans. Front Microbiol 2024; 15:1437579. [PMID: 39119141 PMCID: PMC11306161 DOI: 10.3389/fmicb.2024.1437579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2024] [Accepted: 07/16/2024] [Indexed: 08/10/2024] Open
Abstract
Small GTPases of the Rab family coordinate multiple membrane fusion and trafficking events in eukaryotes. In fungi, the Rab GTPase, Ypt7, plays a critical role in late endosomal trafficking, and is required for homotypic fusion events in vacuole biogenesis and inheritance. In this study, we identified a putative YPT7 homologue in Cryptococcus neoformans, a fungal pathogen causing life threatening meningoencephalitis in immunocompromised individuals. As part of an ongoing effort to understand mechanisms of iron acquisition in C. neoformans, we established a role for Ypt7 in growth on heme as the sole iron source. Deletion of YPT7 also caused abnormal vacuolar morphology, defective endocytic trafficking and autophagy, and mislocalization of Aph1, a secreted vacuolar acid phosphatase. Ypt7 localized to the vacuolar membrane and membrane contact sites between the vacuole and mitochondria (vCLAMPs), and loss of the protein impaired growth on inhibitors of the electron transport chain. Additionally, Ypt7 was required for robust growth at 39°C, a phenotype likely involving the calcineurin signaling pathway because ypt7 mutants displayed increased susceptibility to the calcineurin-specific inhibitors, FK506 and cyclosporin A; the mutants also had impaired growth in either limiting or high levels of calcium. Finally, Ypt7 was required for survival during interactions with macrophages, and ypt7 mutants were attenuated for virulence in a mouse inhalation model thus demonstrating the importance of membrane trafficking functions in cryptococcosis.
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Affiliation(s)
- Guanggan Hu
- The Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
| | - Xianya Qu
- The Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Kabir Bhalla
- The Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Peng Xue
- The Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
| | - Erik Bakkeren
- The Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Christopher W. J. Lee
- The Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - James W. Kronstad
- The Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
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3
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Zhu X, Jin F, Yang G, Zhuang T, Zhang C, Zhou H, Niu X, Wang H, Wu D. Mitochondrial Protease Oct1p Regulates Mitochondrial Homeostasis and Influences Pathogenicity through Affecting Hyphal Growth and Biofilm Formation Activities in Candida albicans. J Fungi (Basel) 2024; 10:391. [PMID: 38921377 PMCID: PMC11204688 DOI: 10.3390/jof10060391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 05/24/2024] [Accepted: 05/28/2024] [Indexed: 06/27/2024] Open
Abstract
Mitochondria, as the core metabolic organelles, play a crucial role in aerobic respiration/biosynthesis in fungi. Numerous studies have demonstrated a close relationship between mitochondria and Candida albicans virulence and drug resistance. Here, we report an octapeptide-aminopeptidase located in the mitochondrial matrix named Oct1p. Its homolog in the model fungus Saccharomyces cerevisiae is one of the key proteins in maintaining mitochondrial respiration and protein stability. In this study, we utilized evolutionary tree analysis, gene knockout experiments, mitochondrial function detection, and other methods to demonstrate the impact of Oct1p on the mitochondrial function of C. albicans. Furthermore, through transcriptome analysis, real-time quantitative PCR, and morphological observation, we discovered that the absence of Oct1p results in functional abnormalities in C. albicans, affecting hyphal growth, cell adhesion, and biofilm formation. Finally, the in vivo results of the infection of Galleria mellonella larvae and vulvovaginal candidiasis in mice indicate that the loss of Oct1p led to the decreased virulence of C. albicans. In conclusion, this study provides a solid theoretical foundation for treating Candida diseases, developing new targeted drugs, and serves as a valuable reference for investigating the connection between mitochondria and virulence in other pathogenic fungi.
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Affiliation(s)
- Xiaoxiao Zhu
- Department of Pathogenic Biology and Immunology, College of Integrated Chinese and Western Medicine, Anhui University of Chinese Medicine, 350 Longzihu Road, Hefei 230012, China
| | - Feng Jin
- Department of Pathogenic Biology and Immunology, College of Integrated Chinese and Western Medicine, Anhui University of Chinese Medicine, 350 Longzihu Road, Hefei 230012, China
| | - Guangyuan Yang
- Department of Pathogenic Biology and Immunology, College of Integrated Chinese and Western Medicine, Anhui University of Chinese Medicine, 350 Longzihu Road, Hefei 230012, China
| | - Tian Zhuang
- Department of Pathogenic Biology and Immunology, College of Integrated Chinese and Western Medicine, Anhui University of Chinese Medicine, 350 Longzihu Road, Hefei 230012, China
| | - Cangcang Zhang
- Department of Pathogenic Biology and Immunology, College of Integrated Chinese and Western Medicine, Anhui University of Chinese Medicine, 350 Longzihu Road, Hefei 230012, China
| | - Hanjing Zhou
- Department of Pathogenic Biology and Immunology, College of Integrated Chinese and Western Medicine, Anhui University of Chinese Medicine, 350 Longzihu Road, Hefei 230012, China
| | - Xiaojia Niu
- Department of Pathogenic Biology and Immunology, College of Integrated Chinese and Western Medicine, Anhui University of Chinese Medicine, 350 Longzihu Road, Hefei 230012, China
| | - Hongchen Wang
- Department of Pathogenic Biology and Immunology, College of Integrated Chinese and Western Medicine, Anhui University of Chinese Medicine, 350 Longzihu Road, Hefei 230012, China
| | - Daqiang Wu
- Department of Pathogenic Biology and Immunology, College of Integrated Chinese and Western Medicine, Anhui University of Chinese Medicine, 350 Longzihu Road, Hefei 230012, China
- Key Laboratory of Xin’an Medicine, Ministry of Education, College of Nursing, Anhui University of Chinese Medicine, 350 Longzihu Road, Hefei 230038, China
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4
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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.
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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.
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5
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XUE P, SÁNCHEZ-LEÓN E, DAMOO D, HU G, JUNG WH, KRONSTAD JW. Heme sensing and trafficking in fungi. FUNGAL BIOL REV 2023; 43:100286. [PMID: 37781717 PMCID: PMC10540271 DOI: 10.1016/j.fbr.2022.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Fungal pathogens cause life-threatening diseases in humans, and the increasing prevalence of these diseases emphasizes the need for new targets for therapeutic intervention. Nutrient acquisition during infection is a promising target, and recent studies highlight the contributions of endomembrane trafficking, mitochondria, and vacuoles in the sensing and acquisition of heme by fungi. These studies have been facilitated by genetically encoded biosensors and other tools to quantitate heme in subcellular compartments and to investigate the dynamics of trafficking in living cells. In particular, the applications of biosensors in fungi have been extended beyond the detection of metabolites, cofactors, pH, and redox status to include the detection of heme. Here, we focus on studies that make use of biosensors to examine mechanisms of heme uptake and degradation, with guidance from the model fungus Saccharomyces cerevisiae and an emphasis on the pathogenic fungi Candida albicans and Cryptococcus neoformans that threaten human health. These studies emphasize a role for endocytosis in heme uptake, and highlight membrane contact sites involving mitochondria, the endoplasmic reticulum and vacuoles as mediators of intracellular iron and heme trafficking.
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Affiliation(s)
- Peng XUE
- Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Eddy SÁNCHEZ-LEÓN
- Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Djihane DAMOO
- Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Guanggan HU
- Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Won Hee JUNG
- Department of Systems Biotechnology, Chung-Ang University, Anseong 17546, Korea
| | - James W. KRONSTAD
- Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
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6
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Mitochondria in Cryptococcus: an update of mitochondrial transcriptional regulation in Cryptococcus. Curr Genet 2023; 69:1-6. [PMID: 36729179 DOI: 10.1007/s00294-023-01261-7] [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: 12/27/2022] [Revised: 01/19/2023] [Accepted: 01/19/2023] [Indexed: 02/03/2023]
Abstract
Encapsulated Cryptococcus species are responsible for approximately 15% of AIDS-related mortality. Numerous intriguing investigations have demonstrated that mitochondria play a crucial role in the pathogen-host axis of microorganisms. Mitochondria are vital energy-generating organelles, but they also regulate a variety of cellular activities, such as fungal adaptability in the host and drug resistance. Mitochondria are also the source of reactive oxygen species, which serve as intracellular messengers but are harmful when produced in excess. Thus, precise and stringent regulation of mitochondrial activity, including oxidative phosphorylation and the ROS detoxification process, is essential to ensure that only the amount required to maintain basic biological activities and prevent ROS toxicity in the cell is maintained. However, the relationship between mitochondria and the pathogenicity of Cryptococcus remains poorly understood. In this review, we focus on transcription regulation and maintenance of mitochondrial function along the pathogen-host interaction axis, as well as prospective antifungal strategies that target mitochondria.
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7
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Hu G, Bakkeren E, Caza M, Horianopoulos L, Sánchez-León E, Sorensen M, Jung W, Kronstad JW. Vam6/Vps39/TRAP1-domain proteins influence vacuolar morphology, iron acquisition and virulence in Cryptococcus neoformans. Cell Microbiol 2021; 23:e13400. [PMID: 34800311 DOI: 10.1111/cmi.13400] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Revised: 11/05/2021] [Accepted: 11/16/2021] [Indexed: 12/21/2022]
Abstract
The pathogenic fungus Cryptococcus neoformans must overcome iron limitation to cause disease in mammalian hosts. Previously, we reported a screen for insertion mutants with poor growth on haem as the sole iron source. In this study, we characterised one such mutant and found that the defective gene encoded a Vam6/Vps39/TRAP1 domain-containing protein required for robust growth on haem, an important iron source in host tissue. We designated this protein Vps3 based on reciprocal best matches with the corresponding protein in Saccharomyces cerevisiae. C. neoformans encodes a second Vam6/Vps39/TRAP1 domain-containing protein designated Vam6/Vlp1, and we found that this protein is also required for robust growth on haem as well as on inorganic iron sources. This protein is predicted to be a component of the homotypic fusion and vacuole protein sorting complex involved in endocytosis. Further characterisation of the vam6Δ and vps3Δ mutants revealed perturbed trafficking of iron acquisition functions (e.g., the high affinity iron permease Cft1) and impaired processing of the transcription factor Rim101, a regulator of haem and iron acquisition. The vps3Δ and vam6Δ mutants also had pleiotropic phenotypes including loss of virulence in a mouse model of cryptococcosis, reduced virulence factor elaboration and increased susceptibility to stress, indicating pleiotropic roles for Vps3 and Vam6 beyond haem use in C. neoformans. TAKE AWAYS: Two Vam6/Vps39/TRAP1-domain proteins, Vps3 and Vam6, support the growth of Cryptococcus neoformans on haem. Loss of Vps3 and Vam6 influences the trafficking and expression of iron uptake proteins. Loss of Vps3 or Vam6 eliminates the ability of C. neoformans to cause disease in a mouse model of cryptococcosis.
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Affiliation(s)
- Guanggan Hu
- The Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Erik Bakkeren
- The Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Zoology, University of Oxford, Oxford, UK
| | - Mélissa Caza
- The Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada.,Larissa Yarr Medical Microbiology Laboratory, Kelowna General Hospital, Kelowna, British Columbia, Canada
| | - Linda Horianopoulos
- The Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Eddy Sánchez-León
- The Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Melanie Sorensen
- The Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Wonhee Jung
- Department of Systems Biotechnology, Chung-Ang University, Anseong, Republic of Korea
| | - James W Kronstad
- The Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
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8
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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: 14] [Impact Index Per Article: 4.7] [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:
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9
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Navarro-Espíndola R, Suaste-Olmos F, Peraza-Reyes L. Dynamic Regulation of Peroxisomes and Mitochondria during Fungal Development. J Fungi (Basel) 2020; 6:E302. [PMID: 33233491 PMCID: PMC7711908 DOI: 10.3390/jof6040302] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 10/22/2020] [Accepted: 10/23/2020] [Indexed: 12/11/2022] Open
Abstract
Peroxisomes and mitochondria are organelles that perform major functions in the cell and whose activity is very closely associated. In fungi, the function of these organelles is critical for many developmental processes. Recent studies have disclosed that, additionally, fungal development comprises a dynamic regulation of the activity of these organelles, which involves a developmental regulation of organelle assembly, as well as a dynamic modulation of the abundance, distribution, and morphology of these organelles. Furthermore, for many of these processes, the dynamics of peroxisomes and mitochondria are governed by common factors. Notably, intense research has revealed that the process that drives the division of mitochondria and peroxisomes contributes to several developmental processes-including the formation of asexual spores, the differentiation of infective structures by pathogenic fungi, and sexual development-and that these processes rely on selective removal of these organelles via autophagy. Furthermore, evidence has been obtained suggesting a coordinated regulation of organelle assembly and dynamics during development and supporting the existence of regulatory systems controlling fungal development in response to mitochondrial activity. Gathered information underscores an important role for mitochondrial and peroxisome dynamics in fungal development and suggests that this process involves the concerted activity of these organelles.
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Affiliation(s)
| | | | - Leonardo Peraza-Reyes
- Departamento de Bioquímica y Biología Estructural, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico; (R.N.-E.); (F.S.-O.)
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10
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de Curcio JS, Oliveira LN, Batista MP, Novaes E, de Almeida Soares CM. MiRNAs regulate iron homeostasis in Paracoccidioides brasiliensis. Microbes Infect 2020; 23:104772. [PMID: 33157279 DOI: 10.1016/j.micinf.2020.10.008] [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: 04/09/2020] [Revised: 10/17/2020] [Accepted: 10/27/2020] [Indexed: 11/19/2022]
Abstract
During pathogen interaction with the host, several mechanisms are used to favor or inhibit the infectious process; one is called nutritional immunity, characterized by restriction of micronutrients to pathogens. Several studies on fungi of the Paracoccidioides complex, have demonstrated that these pathogens remodel their metabolic pathways to overcome the hostile condition imposed by the host. However, molecular mechanisms that control the regulation of those metabolic changes are not fully understood. Therefore, this work characterizes the expression profile of miRNAs during iron deprivation and describes metabolic pathways putatively regulated by those molecules. Through analysis of RNAseq, 45 miRNAs were identified and eight presented alterations in the expression profile during iron deprivation. Among the differentially regulated miRNAs, five were more abundant in yeast cells during iron deprivation and interestingly, the analyses of genes potentially regulated by those five miRNAs, pointed to metabolic pathways as oxidative phosphorylation, altered in response to iron deprivation. In addition, miRNAs with more abundance in iron presence, have as target genes encoding transcriptional factors related to iron homeostasis and uptake. Therefore, we suggest that miRNAs produced by Paracoccidioides brasiliensis may contribute to the adaptive responses of this fungus in iron starvation environment.
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Affiliation(s)
- Juliana S de Curcio
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Campus II Samambaia, CEP: 74690-900, Goiânia, Goiás, Brazil
| | - Lucas Nojosa Oliveira
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Campus II Samambaia, CEP: 74690-900, Goiânia, Goiás, Brazil
| | - Mariana P Batista
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Campus II Samambaia, CEP: 74690-900, Goiânia, Goiás, Brazil
| | - Evandro Novaes
- Departamento de Biologia, Universidade Federal de Lavras, Minas Gerais, CEP: 37200-000, Brazil
| | - Célia Maria de Almeida Soares
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Campus II Samambaia, CEP: 74690-900, Goiânia, Goiás, Brazil.
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11
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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: 12] [Impact Index Per Article: 3.0] [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.
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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;
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12
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Misslinger M, Hortschansky P, Brakhage AA, Haas H. Fungal iron homeostasis with a focus on Aspergillus fumigatus. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1868:118885. [PMID: 33045305 DOI: 10.1016/j.bbamcr.2020.118885] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/15/2020] [Accepted: 10/01/2020] [Indexed: 02/08/2023]
Abstract
To maintain iron homeostasis, fungi have to balance iron acquisition, storage, and utilization to ensure sufficient supply and to avoid toxic excess of this essential trace element. As pathogens usually encounter iron limitation in the host niche, this metal plays a particular role during virulence. Siderophores are iron-chelators synthesized by most, but not all fungal species to sequester iron extra- and intracellularly. In recent years, the facultative human pathogen Aspergillus fumigatus has become a model for fungal iron homeostasis of siderophore-producing fungal species. This article summarizes the knowledge on fungal iron homeostasis and its links to virulence with a focus on A. fumigatus. It covers mechanisms for iron acquisition, storage, and detoxification, as well as the modes of transcriptional iron regulation and iron sensing in A. fumigatus in comparison to other fungal species. Moreover, potential translational applications of the peculiarities of fungal iron metabolism for treatment and diagnosis of fungal infections is addressed.
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Affiliation(s)
- Matthias Misslinger
- Institute of Molecular Biology - Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Peter Hortschansky
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute (HKI), Jena, Germany
| | - Axel A Brakhage
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute (HKI), Jena, Germany; Department Microbiology and Molecular Biology, Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany
| | - Hubertus Haas
- Institute of Molecular Biology - Biocenter, Medical University of Innsbruck, Innsbruck, Austria.
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A Cytoplasmic Heme Sensor Illuminates the Impacts of Mitochondrial and Vacuolar Functions and Oxidative Stress on Heme-Iron Homeostasis in Cryptococcus neoformans. mBio 2020; 11:mBio.00986-20. [PMID: 32723917 PMCID: PMC7387795 DOI: 10.1128/mbio.00986-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Invasive fungal diseases are increasing in frequency, and new drug targets and antifungal drugs are needed to bolster therapy. The mechanisms by which pathogens obtain critical nutrients such as iron from heme during host colonization represent a promising target for therapy. In this study, we employed a fluorescent heme sensor to investigate heme homeostasis in Cryptococcus neoformans. We demonstrated that endocytosis is a key aspect of heme acquisition and that vacuolar and mitochondrial functions are important in regulating the pool of available heme in cells. Stress generated by oxidative conditions impacts the heme pool, as do the drugs artemisinin and metformin; these drugs have heme-related activities and are in clinical use for malaria and diabetes, respectively. Overall, our study provides insights into mechanisms of fungal heme acquisition and demonstrates the utility of the heme sensor for drug characterization in support of new therapies for fungal diseases. Pathogens must compete with hosts to acquire sufficient iron for proliferation during pathogenesis. The pathogenic fungus Cryptococcus neoformans is capable of acquiring iron from heme, the most abundant source in vertebrate hosts, although the mechanisms of heme sensing and acquisition are not entirely understood. In this study, we adopted a chromosomally encoded heme sensor developed for Saccharomyces cerevisiae to examine cytosolic heme levels in C. neoformans using fluorescence microscopy, fluorimetry, and flow cytometry. We validated the responsiveness of the sensor upon treatment with exogenous hemin, during proliferation in macrophages, and in strains defective for endocytosis. We then used the sensor to show that vacuolar and mitochondrial dysregulation and oxidative stress reduced the labile heme pool in the cytosol. Importantly, the sensor provided a tool to further demonstrate that the drugs artemisinin and metformin have heme-related activities and the potential to be repurposed for antifungal therapy. Overall, this study provides insights into heme sensing by C. neoformans and establishes a powerful tool to further investigate mechanisms of heme-iron acquisition in the context of fungal pathogenesis.
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Martínez-Pastor MT, Puig S. Adaptation to iron deficiency in human pathogenic fungi. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1867:118797. [PMID: 32663505 DOI: 10.1016/j.bbamcr.2020.118797] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 06/13/2020] [Accepted: 07/05/2020] [Indexed: 02/08/2023]
Abstract
Iron is an essential micronutrient for virtually all eukaryotic organisms and plays a central role during microbial infections. Invasive fungal diseases are associated with strikingly high rates of mortality, but their impact on human health is usually underestimated. Upon a fungal infection, hosts restrict iron availability in order to limit the growth and virulence of the pathogen. Here, we use two model yeasts, Saccharomyces cerevisiae and Schizosaccharomyces pombe, to delve into the response to iron deficiency of human fungal pathogens, such as Candida glabrata, Candida albicans, Aspergillus fumigatus and Cryptococcus neoformans. Fungi possess common and species-specific mechanisms to acquire iron and to control the response to iron limitation. Upon iron scarcity, fungi activate a wide range of elegant strategies to capture and import exogenous iron, mobilize iron from intracellular stores, and modulate their metabolism to economize and prioritize iron utilization. Hence, iron homeostasis genes represent remarkable virulence factors that can be used as targets for the development of novel antifungal treatments.
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Affiliation(s)
| | - Sergi Puig
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Paterna, Valencia, Spain.
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15
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Gupta M, Outten CE. Iron-sulfur cluster signaling: The common thread in fungal iron regulation. Curr Opin Chem Biol 2020; 55:189-201. [PMID: 32234663 DOI: 10.1016/j.cbpa.2020.02.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 02/02/2020] [Accepted: 02/20/2020] [Indexed: 02/07/2023]
Abstract
Iron homeostasis in fungi involves balancing iron uptake and storage with iron utilization to achieve adequate, nontoxic levels of this essential nutrient. Extensive work in the nonpathogenic yeast Saccharomyces cerevisiae and Schizosaccharomyces pombe has uncovered unique iron regulation networks for each organism that control iron metabolism via distinct molecular mechanisms. However, common themes have emerged from these studies. The activities of all fungal iron-sensing transcription factors characterized to date are regulated via iron-sulfur cluster signaling. Furthermore, glutaredoxins often play a key role in relaying the intracellular iron status to these DNA-binding proteins. Recent work with fungal pathogens, including Candida and Aspergillus species and Cryptococcus neoformans, has revealed novel iron regulation mechanisms, yet similar roles for iron-sulfur clusters and glutaredoxins in iron signaling have been confirmed. This review will focus on these recent discoveries regarding iron regulation pathways in both pathogenic and nonpathogenic fungi.
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Affiliation(s)
- Malini Gupta
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC, USA 29208
| | - Caryn E Outten
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC, USA 29208.
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Baksh KA, Zamble DB. Allosteric control of metal-responsive transcriptional regulators in bacteria. J Biol Chem 2020; 295:1673-1684. [PMID: 31857375 PMCID: PMC7008368 DOI: 10.1074/jbc.rev119.011444] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Many transition metals are essential trace nutrients for living organisms, but they are also cytotoxic in high concentrations. Bacteria maintain the delicate balance between metal starvation and toxicity through a complex network of metal homeostasis pathways. These systems are coordinated by the activities of metal-responsive transcription factors-also known as metal-sensor proteins or metalloregulators-that are tuned to sense the bioavailability of specific metals in the cell in order to regulate the expression of genes encoding proteins that contribute to metal homeostasis. Metal binding to a metalloregulator allosterically influences its ability to bind specific DNA sequences through a variety of intricate mechanisms that lie on a continuum between large conformational changes and subtle changes in internal dynamics. This review summarizes recent advances in our understanding of how metal sensor proteins respond to intracellular metal concentrations. In particular, we highlight the allosteric mechanisms used for metal-responsive regulation of several prokaryotic single-component metalloregulators, and we briefly discuss current open questions of how metalloregulators function in bacterial cells. Understanding the regulation and function of metal-responsive transcription factors is a fundamental aspect of metallobiochemistry and is important for gaining insights into bacterial growth and virulence.
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Affiliation(s)
- Karina A Baksh
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Deborah B Zamble
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada.
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