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Luo G, Zhang J, Wang T, Cui H, Bai Y, Luo J, Zhang J, Zhang M, Di L, Yuan Y, Xiong K, Yu X, Zhang Y, Shen C, Zhu C, Wang Y, Su C, Lu Y. A human commensal-pathogenic fungus suppresses host immunity via targeting TBK1. Cell Host Microbe 2024:S1931-3128(24)00262-2. [PMID: 39084229 DOI: 10.1016/j.chom.2024.07.003] [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: 03/14/2024] [Revised: 06/11/2024] [Accepted: 07/05/2024] [Indexed: 08/02/2024]
Abstract
Candida albicans stably colonizes humans but is the leading cause of hospital-acquired fungemia. Traditionally, masking immunogenic moieties has been viewed as a tactic for immune evasion. Here, we demonstrate that C. albicans blocks type I interferon (IFN-I) signaling via translocating an effector protein Cmi1 into host cells. Mechanistically, Cmi1 binds and inhibits TANK-binding kinase 1 (TBK1) to abrogate IFN-regulatory factor 3 (IRF3) phosphorylation, thereby suppressing the IFN-I cascade. Murine infection with a cmi1 mutant displays an exaggerated IFN-I response in both kidneys and bone-marrow-derived macrophages, leading to rapid fungal clearance and host survival. Remarkably, the lack of CMI1 compromises gut commensalism and increases IFN-I response in mouse colonic cells. These phenotypes of cmi1 are rescued by the depletion of IFN-I receptor. This work establishes the importance of TBK1 inhibition in fungal pathogenesis and reveals that a human commensal-pathogenic fungus significantly impacts host immunity during gut colonization and infection via delivering effector proteins into host cells.
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Affiliation(s)
- Gang Luo
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan 430072, China
| | - Jingkai Zhang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan 430072, China
| | - Tianxu Wang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan 430072, China
| | - Hao Cui
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan 430072, China
| | - Yukun Bai
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan 430072, China
| | - Jianchen Luo
- College of Life Sciences, Zhejiang University, Hangzhou 310027, China
| | - Jinqiu Zhang
- College of Life Sciences, Zhejiang University, Hangzhou 310027, China
| | - Mao Zhang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Linyan Di
- Tianjin Key Laboratory of Function and Application of Biological Macromolecular Structures, School of Life Sciences, Tianjin University, Tianjin 300072, China
| | - Yuncong Yuan
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Kang Xiong
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Xiangtai Yu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Yaling Zhang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan 430072, China
| | - Chao Shen
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Cheng Zhu
- Tianjin Key Laboratory of Function and Application of Biological Macromolecular Structures, School of Life Sciences, Tianjin University, Tianjin 300072, China
| | - Yong Wang
- College of Life Sciences, Zhejiang University, Hangzhou 310027, China
| | - Chang Su
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Yang Lu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan 430072, China.
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Silao FGS, Valeriano VD, Uddström E, Falconer E, Ljungdahl PO. Diverse mechanisms control amino acid-dependent environmental alkalization by Candida albicans. Mol Microbiol 2024; 121:696-716. [PMID: 38178569 DOI: 10.1111/mmi.15216] [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: 11/24/2023] [Revised: 12/12/2023] [Accepted: 12/14/2023] [Indexed: 01/06/2024]
Abstract
Candida albicans has the capacity to neutralize acidic growth environments by releasing ammonia derived from the catabolism of amino acids. The molecular components underlying alkalization and its physiological significance remain poorly understood. Here, we present an integrative model with the cytosolic NAD+-dependent glutamate dehydrogenase (Gdh2) as the principal ammonia-generating component. We show that alkalization is dependent on the SPS-sensor-regulated transcription factor STP2 and the proline-responsive activator Put3. These factors function in parallel to derepress GDH2 and the two proline catabolic enzymes PUT1 and PUT2. Consistently, a double mutant lacking STP2 and PUT3 exhibits a severe alkalization defect that nearly phenocopies that of a gdh2-/- strain. Alkalization is dependent on mitochondrial activity and in wild-type cells occurs as long as the conditions permit respiratory growth. Strikingly, Gdh2 levels decrease and cells transiently extrude glutamate as the environment becomes more alkaline. Together, these processes constitute a rudimentary regulatory system that counters and limits the negative effects associated with ammonia generation. These findings align with Gdh2 being dispensable for virulence, and based on a whole human blood virulence assay, the same is true for C. glabrata and C. auris. Using a transwell co-culture system, we observed that the growth and proliferation of Lactobacillus crispatus, a common component of the acidic vaginal microenvironment and a potent antagonist of C. albicans, is unaffected by fungal-induced alkalization. Consequently, although Candida spp. can alkalinize their growth environments, other fungal-associated processes are more critical in promoting dysbiosis and virulent fungal growth.
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Affiliation(s)
- Fitz Gerald S Silao
- Department of Molecular Biosciences, The Wenner-Gren Institute, Science for Life Laboratory (SciLifeLab), Stockholm University, Stockholm, Sweden
| | - Valerie Diane Valeriano
- Centre for Translational Microbiome Research (CTMR), Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Solna, Sweden
| | - Erika Uddström
- Department of Molecular Biosciences, The Wenner-Gren Institute, Science for Life Laboratory (SciLifeLab), Stockholm University, Stockholm, Sweden
| | - Emilie Falconer
- Department of Molecular Biosciences, The Wenner-Gren Institute, Science for Life Laboratory (SciLifeLab), Stockholm University, Stockholm, Sweden
| | - Per O Ljungdahl
- Department of Molecular Biosciences, The Wenner-Gren Institute, Science for Life Laboratory (SciLifeLab), Stockholm University, Stockholm, Sweden
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3
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Sonnberger J, Kasper L, Lange T, Brunke S, Hube B. "We've got to get out"-Strategies of human pathogenic fungi to escape from phagocytes. Mol Microbiol 2024; 121:341-358. [PMID: 37800630 DOI: 10.1111/mmi.15149] [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: 06/30/2023] [Revised: 08/08/2023] [Accepted: 08/16/2023] [Indexed: 10/07/2023]
Abstract
Human fungal pathogens are a deadly and underappreciated risk to global health that most severely affect immunocompromised individuals. A virulence attribute shared by some of the most clinically relevant fungal species is their ability to survive inside macrophages and escape from these immune cells. In this review, we discuss the mechanisms behind intracellular survival and elaborate how escape is mediated by lytic and non-lytic pathways as well as strategies to induce programmed host cell death. We also discuss persistence as an alternative to rapid host cell exit. In the end, we address the consequences of fungal escape for the host immune response and provide future perspectives for research and development of targeted therapies.
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Affiliation(s)
- Johannes Sonnberger
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, Jena, Germany
| | - Lydia Kasper
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, Jena, Germany
| | - Theresa Lange
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, Jena, Germany
| | - Sascha Brunke
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, Jena, Germany
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, Jena, Germany
- Institute of Microbiology, Friedrich Schiller University, Jena, Germany
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Li S, Liu Y, Weng L, Zhao Y, Zhang Y, Zhang Z, Yang Y, Chen Q, Liu X, Zhang H. The F 1F o-ATP synthase α subunit of Candida albicans induces inflammatory responses by controlling amino acid catabolism. Virulence 2023; 14:2190645. [PMID: 36914568 PMCID: PMC10072111 DOI: 10.1080/21505594.2023.2190645] [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: 10/29/2022] [Revised: 02/08/2023] [Accepted: 03/09/2023] [Indexed: 03/15/2023] Open
Abstract
Sepsis is a leading cause of fatality in invasive candidiasis. The magnitude of the inflammatory response is a determinant of sepsis outcomes, and inflammatory cytokine imbalances are central to the pathophysiological processes. We previously demonstrated that a Candida albicans F1Fo-ATP synthase α subunit deletion mutant was nonlethal to mice. Here, the potential effects of the F1Fo-ATP synthase α subunit on host inflammatory responses and the mechanism were studied. Compared with wild-type strain, the F1Fo-ATP synthase α subunit deletion mutant failed to induce inflammatory responses in Galleria mellonella and murine systemic candidiasis models and significantly decreased the mRNA levels of the proinflammatory cytokines IL-1β, IL-6 and increased those of the anti-inflammatory cytokine IL-4 in the kidney. During C. albicans-macrophage co-culture, the F1Fo-ATP synthase α subunit deletion mutant was trapped inside macrophages in yeast form, and its filamentation, a key factor in inducing inflammatory responses, was inhibited. In the macrophage-mimicking microenvironment, the F1Fo-ATP synthase α subunit deletion mutant blocked the cAMP/PKA pathway, the core filamentation-regulating pathway, because it failed to alkalinize environment by catabolizing amino acids, an important alternative carbon source inside macrophages. The mutant downregulated Put1 and Put2, two essential amino acid catabolic enzymes, possibly due to severely impaired oxidative phosphorylation. Our findings reveal that the C. albicans F1Fo-ATP synthase α subunit induces host inflammatory responses by controlling its own amino acid catabolism and it is significant to find drugs that inhibit F1Fo-ATP synthase α subunit activity to control the induction of host inflammatory responses.
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Affiliation(s)
- Shuixiu Li
- 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
| | - Luobei Weng
- Department of Dermatology, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong, China
- Institute of Mycology, Jinan University, Guangzhou, Guangdong, China
| | - Yajing Zhao
- 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
| | - Zhanpeng Zhang
- Department of Dermatology, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong, China
- Institute of Mycology, Jinan University, Guangzhou, Guangdong, China
| | - Yang Yang
- Department of Dermatology, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong, China
- Institute of Mycology, Jinan University, Guangzhou, Guangdong, China
| | - Qiaoxin Chen
- Department of Dermatology, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong, China
- Institute of Mycology, Jinan University, Guangzhou, Guangdong, China
| | - Xiaocong Liu
- Department of Dermatology, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong, China
- Institute of Mycology, Jinan University, Guangzhou, Guangdong, China
| | - Hong Zhang
- Department of Dermatology, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong, China
- Institute of Mycology, Jinan University, Guangzhou, Guangdong, China
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5
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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.
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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
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6
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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.
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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
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Druseikis M, Mottola A, Berman J. The Metabolism of Susceptibility: Clearing the FoG Between Tolerance and Resistance in Candida albicans. CURRENT CLINICAL MICROBIOLOGY REPORTS 2023; 10:36-46. [DOI: 10.1007/s40588-023-00189-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
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8
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Brown AJP. Fungal resilience and host-pathogen interactions: Future perspectives and opportunities. Parasite Immunol 2023; 45:e12946. [PMID: 35962618 PMCID: PMC10078341 DOI: 10.1111/pim.12946] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 08/08/2022] [Accepted: 08/10/2022] [Indexed: 01/31/2023]
Abstract
We are constantly exposed to the threat of fungal infection. The outcome-clearance, commensalism or infection-depends largely on the ability of our innate immune defences to clear infecting fungal cells versus the success of the fungus in mounting compensatory adaptive responses. As each seeks to gain advantage during these skirmishes, the interactions between host and fungal pathogen are complex and dynamic. Nevertheless, simply compromising the physiological robustness of fungal pathogens reduces their ability to evade antifungal immunity, their virulence, and their tolerance against antifungal therapy. In this article I argue that this physiological robustness is based on a 'Resilience Network' which mechanistically links and controls fungal growth, metabolism, stress resistance and drug tolerance. The elasticity of this network probably underlies the phenotypic variability of fungal isolates and the heterogeneity of individual cells within clonal populations. Consequently, I suggest that the definition of the fungal Resilience Network represents an important goal for the future which offers the clear potential to reveal drug targets that compromise drug tolerance and synergise with current antifungal therapies.
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Affiliation(s)
- Alistair J P Brown
- Medical Research Council Centre for Medical Mycology at the University of Exeter, Exeter, UK
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9
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Zhao S, Shang A, Guo M, Shen L, Han Y, Huang X. The advances in the regulation of immune microenvironment by Candida albicans and macrophage cross-talk. Front Microbiol 2022; 13:1029966. [PMID: 36466634 PMCID: PMC9717684 DOI: 10.3389/fmicb.2022.1029966] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Accepted: 11/07/2022] [Indexed: 04/04/2024] Open
Abstract
Candida albicans (C. albicans) is the most common causative agent of invasive fungal infections in hospitals. The body defends against and eliminates C. albicans infection by various mechanisms of immune response, and the latter mechanism of immune evasion is a major challenge in the clinical management of C. albicans infection. The role of macrophages in combating C. albicans infection has only recently been recognized, but the mechanisms remain to be elucidated. This review focuses on the interaction between C. albicans and macrophages (macrophages), which causes the body to generate an immune response or C. albicans immune escape, and then regulates the body's immune microenvironment, to explore the effect of C. albicans virulence resistance vs. macrophage killing and clarify the role and mechanism of C. albicans pathogenesis. In general, a thorough understanding of the molecular principles driving antifungal drug resistance is essential for the development of innovative treatments that can counteract both existing and emerging fungal threats.
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Affiliation(s)
- Shuo Zhao
- Department of Dermatology, School of Medicine, Tongji Hospital, Tongji University, Shanghai, China
| | - Anquan Shang
- Department of Laboratory Medicine, The Second People’s Hospital of Lianyungang, Lianyungang, China
| | - Mengchen Guo
- Department of Dermatology, School of Medicine, Tongji Hospital, Tongji University, Shanghai, China
| | - Liangliang Shen
- Department of Dermatology, School of Medicine, Tongji Hospital, Tongji University, Shanghai, China
| | - Yu Han
- Department of Dermatology, School of Medicine, Tongji Hospital, Tongji University, Shanghai, China
| | - Xin Huang
- Department of Dermatology, School of Medicine, Tongji Hospital, Tongji University, Shanghai, China
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10
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Dey T, Rangarajan PN. Posttranscriptional regulation of glutamate dehydrogenase 2 and phosphoenolpyruvate carboxykinase in Komagataella phaffii. Yeast 2022; 39:337-347. [PMID: 35384037 DOI: 10.1002/yea.3704] [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: 12/08/2021] [Revised: 02/25/2022] [Accepted: 03/22/2022] [Indexed: 11/09/2022] Open
Abstract
The yeast Komagataella phaffii (a.k.a. Pichia pastoris) harbours a unique glutamate utilization pathway in which the cytosolic enzymes glutamate dehydrogenase 2 (GDH2), aspartate aminotransferase 2 (AAT2) and phosphoenolpyruvate carboxykinase (PEPCK) catalyze the sequential conversion of glutamate to α-ketoglutarate, oxaloacetate and phosphoenolpyruvate respectively. GDH2 and PEPCK are essential for glutamate catabolism. Their synthesis is induced by autophagy during carbon starvation and are essential for cell survival. Here, we demonstrate that GDH2 and PEPCK reciprocally regulate each other's protein levels during glutamate catabolism such that GDH2 is downregulated in Δpepck and PEPCK is downregulated in Δgdh2. We further demonstrate that sequential conversion of glutamate to α-ketoglutarate and oxaloacetate by GDH2 and AAT2, respectively, is essential for PEPCK synthesis in cells metabolizing glutamate. Our studies indicate that translation of GDH2 mRNA is induced by glutamate while oxaloacetate derived from glutamate is likely to be the inducer of PEPCK mRNA translation during glutamate catabolism. Thus, GDH2- and PEPCK-catalyzed reactions are essential for ATP generation and gluconeogenesis respectively during carbon starvation and glutamate catabolism in K. phaffii. We conclude that K. phaffii harbours a unique translational regulatory circuit in which substrates of GDH2 and PEPCK act as inducers of their synthesis, a phenomenon not reported in any yeast species.
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Affiliation(s)
- Trishna Dey
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Pundi N Rangarajan
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
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11
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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: 9] [Impact Index Per Article: 3.0] [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.
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12
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Dey T, Rangarajan PN. Carbon starvation-induced synthesis of GDH2 and PEPCK is essential for the survival of Pichia pastoris. Biochem Biophys Res Commun 2021; 581:25-30. [PMID: 34653675 DOI: 10.1016/j.bbrc.2021.10.015] [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: 09/30/2021] [Accepted: 10/06/2021] [Indexed: 12/01/2022]
Abstract
The industrial yeast Pichia pastoris can utilize amino acids as the sole source of carbon. It possesses a post-transcriptional regulatory circuit that governs the synthesis of cytosolic glutamate dehydrogenase 2 (GDH2) and phosphoenolpyruvate carboxykinase (PEPCK), key enzymes of amino acid catabolism. Here, we demonstrate that the post-transcriptional regulatory circuit is activated during carbon starvation resulting in the translation of GDH2 and PEPCK mRNAs. GDH2 and PEPCK synthesis is abrogated in Δatg1 indicating a key role for autophagy or an autophagy-related process. Finally, carbon-starved Δgdh2 and Δpepck exhibit poor survival. This study demonstrates a key role for amino acid catabolism during carbon starvation, a phenomenon hitherto unreported in other yeast species.
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Affiliation(s)
- Trishna Dey
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560012, India
| | - Pundi N Rangarajan
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560012, India.
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13
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Correction: Correction: Glutamate dehydrogenase (Gdh2)-dependent alkalization is dispensable for escape from macrophages and virulence of Candida albicans. PLoS Pathog 2021; 17:e1010008. [PMID: 34665846 PMCID: PMC8525757 DOI: 10.1371/journal.ppat.1010008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
[This corrects the article DOI: 10.1371/journal.ppat.1009877.].
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Silao FGS, Ryman K, Jiang T, Ward M, Hansmann N, Molenaar C, Liu NN, Chen C, Ljungdahl PO. Correction: Glutamate dehydrogenase (Gdh2)-dependent alkalization is dispensable for escape from macrophages and virulence of Candida albicans. PLoS Pathog 2021; 17:e1009877. [PMID: 34460867 PMCID: PMC8405231 DOI: 10.1371/journal.ppat.1009877] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
[This corrects the article DOI: 10.1371/journal.ppat.1008328.].
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