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Avelar GM, Pradhan A, Ma Q, Hickey E, Leaves I, Liddle C, Rodriguez Rondon AV, Kaune AK, Shaw S, Maufrais C, Sertour N, Bain JM, Larcombe DE, de Assis LJ, Netea MG, Munro CA, Childers DS, Erwig LP, Brown GD, Gow NAR, Bougnoux ME, d'Enfert C, Brown AJP. A CO 2 sensing module modulates β-1,3-glucan exposure in Candida albicans. mBio 2024; 15:e0189823. [PMID: 38259065 PMCID: PMC10865862 DOI: 10.1128/mbio.01898-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 12/11/2023] [Indexed: 01/24/2024] Open
Abstract
Microbial species capable of co-existing with healthy individuals, such as the commensal fungus Candida albicans, exploit multifarious strategies to evade our immune defenses. These strategies include the masking of immunoinflammatory pathogen-associated molecular patterns (PAMPs) at their cell surface. We reported previously that C. albicans actively reduces the exposure of the proinflammatory PAMP, β-1,3-glucan, at its cell surface in response to host-related signals such as lactate and hypoxia. Here, we show that clinical isolates of C. albicans display phenotypic variability with respect to their lactate- and hypoxia-induced β-1,3-glucan masking. We have exploited this variability to identify responsive and non-responsive clinical isolates. We then performed RNA sequencing on these isolates to reveal genes whose expression patterns suggested potential association with lactate- or hypoxia-induced β-1,3-glucan masking. The deletion of two such genes attenuated masking: PHO84 and NCE103. We examined NCE103-related signaling further because NCE103 has been shown previously to encode carbonic anhydrase, which promotes adenylyl cyclase-protein kinase A (PKA) signaling at low CO2 levels. We show that while CO2 does not trigger β-1,3-glucan masking in C. albicans, the Sch9-Rca1-Nce103 signaling module strongly influences β-1,3-glucan exposure in response to hypoxia and lactate. In addition to identifying a new regulatory module that controls PAMP exposure in C. albicans, our data imply that this module is important for PKA signaling in response to environmental inputs other than CO2.IMPORTANCEOur innate immune defenses have evolved to protect us against microbial infection in part via receptor-mediated detection of "pathogen-associated molecular patterns" (PAMPs) expressed by invading microbes, which then triggers their immune clearance. Despite this surveillance, many microbial species are able to colonize healthy, immune-competent individuals, without causing infection. To do so, these microbes must evade immunity. The commensal fungus Candida albicans exploits a variety of strategies to evade immunity, one of which involves reducing the exposure of a proinflammatory PAMP (β-1,3-glucan) at its cell surface. Most of the β-1,3-glucan is located in the inner layer of the C. albicans cell wall, hidden by an outer layer of mannan fibrils. Nevertheless, some β-1,3-glucan can become exposed at the fungal cell surface. However, in response to certain specific host signals, such as lactate or hypoxia, C. albicans activates an anticipatory protective response that decreases β-1,3-glucan exposure, thereby reducing the susceptibility of the fungus to impending innate immune attack. Here, we exploited the natural phenotypic variability of C. albicans clinical isolates to identify strains that do not display the response to β-1,3-glucan masking signals observed for the reference isolate, SC5314. Then, using genome-wide transcriptional profiling, we compared these non-responsive isolates with responsive controls to identify genes potentially involved in β-1,3-glucan masking. Mutational analysis of these genes revealed that a sensing module that was previously associated with CO2 sensing also modulates β-1,3-glucan exposure in response to hypoxia and lactate in this major fungal pathogen of humans.
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Affiliation(s)
- Gabriela M. Avelar
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Arnab Pradhan
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
- Medical Research Council Centre for Medical Mycology, School of Biosciences, University of Exeter, Exeter, United Kingdom
| | - Qinxi Ma
- Medical Research Council Centre for Medical Mycology, School of Biosciences, University of Exeter, Exeter, United Kingdom
| | - Emer Hickey
- Medical Research Council Centre for Medical Mycology, School of Biosciences, University of Exeter, Exeter, United Kingdom
| | - Ian Leaves
- Medical Research Council Centre for Medical Mycology, School of Biosciences, University of Exeter, Exeter, United Kingdom
| | - Corin Liddle
- Bioimaging Unit, University of Exeter, Exeter, United Kingdom
| | - Alejandra V. Rodriguez Rondon
- Medical Research Council Centre for Medical Mycology, School of Biosciences, University of Exeter, Exeter, United Kingdom
| | - Ann-Kristin Kaune
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Sophie Shaw
- Centre for Genome Enabled Biology and Medicine, University of Aberdeen, Aberdeen, United Kingdom
| | - Corinne Maufrais
- Institut Pasteur, Université Paris Cité, INRAe USC2019, Unité Biologie et Pathogénicité Fongiques, Paris, France
- Institut Pasteur, Université Paris Cité, Bioinformatics and Biostatistics Hub, Paris, France
| | - Natacha Sertour
- Institut Pasteur, Université Paris Cité, INRAe USC2019, Unité Biologie et Pathogénicité Fongiques, Paris, France
| | - Judith M. Bain
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Daniel E. Larcombe
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
- Medical Research Council Centre for Medical Mycology, School of Biosciences, University of Exeter, Exeter, United Kingdom
| | - Leandro J. de Assis
- Medical Research Council Centre for Medical Mycology, School of Biosciences, University of Exeter, Exeter, United Kingdom
| | - Mihai G. Netea
- Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, the Netherlands
- Department for Immunology & Metabolism, Life and Medical Sciences Institute (LIMES), University of Bonn, Bonn, Germany
| | - Carol A. Munro
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Delma S. Childers
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Lars P. Erwig
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
- Johnson-Johnson Innovation, EMEA Innovation Centre, London, United Kingdom
| | - Gordon D. Brown
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
- Medical Research Council Centre for Medical Mycology, School of Biosciences, University of Exeter, Exeter, United Kingdom
| | - Neil A. R. Gow
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
- Medical Research Council Centre for Medical Mycology, School of Biosciences, University of Exeter, Exeter, United Kingdom
| | - Marie-Elisabeth Bougnoux
- Institut Pasteur, Université Paris Cité, INRAe USC2019, Unité Biologie et Pathogénicité Fongiques, Paris, France
- Unité de Parasitologie-Mycologie, Service de Microbiologie Clinique, Hôpital Necker-Enfants-Malades, Assistance Publique des Hôpitaux de Paris (APHP), Paris, France
- Université Paris Cité, Paris, France
| | - Christophe d'Enfert
- Institut Pasteur, Université Paris Cité, INRAe USC2019, Unité Biologie et Pathogénicité Fongiques, Paris, France
| | - Alistair J. P. Brown
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
- Medical Research Council Centre for Medical Mycology, School of Biosciences, University of Exeter, Exeter, United Kingdom
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Arita GS, Ma Q, Leaves I, Pradhan A, Hickey E, Dambuza I, Bebes A, Vincenzi Conrado PC, Barros Galinari C, Vicente Seixas FA, Kioshima ÉS, de Souza Bonfim-Mendonça P, Svidzinski TIE, Brown AJP. The impact of ORF19.36.1 in the pathobiology of Candida albicans. Microb Pathog 2023; 185:106437. [PMID: 37913825 DOI: 10.1016/j.micpath.2023.106437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 10/26/2023] [Accepted: 10/29/2023] [Indexed: 11/03/2023]
Abstract
BACKGROUND Our previous proteomics data obtained from Candida albicans recovered after serial passage in a murine model of systemic infection revealed that Orf19.36.1 expression correlates with the virulence of the fungus. Therefore, the impact of ORF19.36.1 upon virulence was tested in this study. MATERIALS & METHODS CRISPR-Cas9 technology was used to construct homozygous C. albicans orf19.36.1 null mutants and the phenotypes of these mutants examined in vitro (filamentation, invasion, adhesion, biofilm formation, hydrolase activities) and in vivo assays. RESULTS The deletion of ORF19.36.1 did not significantly impact the phenotypes examined or the virulence of C. albicans in two infection models. CONCLUSION These results suggest that, although Orf19.36.1 expression correlates with virulence, this protein is not essential for C. albicans pathobiology.
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Affiliation(s)
- Glaucia Sayuri Arita
- Department of Clinical Analysis and Biomedicine, Laboratory of Medical Mycology, State University of Maringa, T20 Building, Room 203, Colombo Avenue, 5790 - Zone 7, Maringá, PR, 87020-900, Brazil
| | - Qinxi Ma
- Medical Research Council Centre for Medical Mycology, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK
| | - Ian Leaves
- Medical Research Council Centre for Medical Mycology, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK
| | - Arnab Pradhan
- Medical Research Council Centre for Medical Mycology, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK
| | - Emer Hickey
- Medical Research Council Centre for Medical Mycology, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK
| | - Ivy Dambuza
- Medical Research Council Centre for Medical Mycology, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK
| | - Attila Bebes
- Centre for Cytomics, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK
| | - Pollyanna Cristina Vincenzi Conrado
- Department of Clinical Analysis and Biomedicine, Laboratory of Medical Mycology, State University of Maringa, T20 Building, Room 203, Colombo Avenue, 5790 - Zone 7, Maringá, PR, 87020-900, Brazil
| | - Camila Barros Galinari
- Department of Clinical Analysis and Biomedicine, Laboratory of Medical Mycology, State University of Maringa, T20 Building, Room 203, Colombo Avenue, 5790 - Zone 7, Maringá, PR, 87020-900, Brazil
| | - Flávio Augusto Vicente Seixas
- Department of Technology, State University of Maringa, Ângelo Moreira da Fonseca Avenue, 1800 - Danielle Park, Umuarama, PR, 87506-370, Brazil
| | - Érika Seki Kioshima
- Department of Clinical Analysis and Biomedicine, Laboratory of Medical Mycology, State University of Maringa, T20 Building, Room 203, Colombo Avenue, 5790 - Zone 7, Maringá, PR, 87020-900, Brazil
| | - Patrícia de Souza Bonfim-Mendonça
- Department of Clinical Analysis and Biomedicine, Laboratory of Medical Mycology, State University of Maringa, T20 Building, Room 203, Colombo Avenue, 5790 - Zone 7, Maringá, PR, 87020-900, Brazil
| | - Terezinha Inez Estivalet Svidzinski
- Department of Clinical Analysis and Biomedicine, Laboratory of Medical Mycology, State University of Maringa, T20 Building, Room 203, Colombo Avenue, 5790 - Zone 7, Maringá, PR, 87020-900, Brazil.
| | - Alistair J P Brown
- Medical Research Council Centre for Medical Mycology, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK
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Martinek J, Cifrová P, Vosolsobě S, García-González J, Malínská K, Mauerová Z, Jelínková B, Krtková J, Sikorová L, Leaves I, Sparkes I, Schwarzerová K. ARP2/3 complex associates with peroxisomes to participate in pexophagy in plants. Nat Plants 2023; 9:1874-1889. [PMID: 37845336 DOI: 10.1038/s41477-023-01542-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 09/11/2023] [Indexed: 10/18/2023]
Abstract
Actin-related protein (ARP2/3) complex is a heteroheptameric protein complex, evolutionary conserved in all eukaryotic organisms. Its conserved role is based on the induction of actin polymerization at the interface between membranes and the cytoplasm. Plant ARP2/3 has been reported to participate in actin reorganization at the plasma membrane during polarized growth of trichomes and at the plasma membrane-endoplasmic reticulum contact sites. Here we demonstrate that individual plant subunits of ARP2/3 fused to fluorescent proteins form motile spot-like structures in the cytoplasm that are associated with peroxisomes in Arabidopsis and tobacco. ARP2/3 is found at the peroxisome periphery and contains the assembled ARP2/3 complex and the WAVE/SCAR complex subunit NAP1. This ARP2/3-positive peroxisomal domain colocalizes with the autophagosome and, under conditions that affect the autophagy, colocalization between ARP2/3 and the autophagosome increases. ARP2/3 subunits co-immunoprecipitate with ATG8f and peroxisome-associated ARP2/3 interact in vivo with the ATG8f marker. Since mutants lacking functional ARP2/3 complex have more peroxisomes than wild type, we suggest that ARP2/3 has a novel role in the process of peroxisome degradation by autophagy, called pexophagy.
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Affiliation(s)
- Jan Martinek
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Petra Cifrová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Stanislav Vosolsobě
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Judith García-González
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Kateřina Malínská
- Imaging Facility of Institute of Experimental Botany AS CR, Prague, Czech Republic
| | - Zdeňka Mauerová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Barbora Jelínková
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Jana Krtková
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Lenka Sikorová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Ian Leaves
- Biosciences, CLES, Exeter University, Exeter, UK
| | - Imogen Sparkes
- School of Biological Sciences, University of Bristol, Bristol, UK
| | - Kateřina Schwarzerová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic.
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Hatinguais R, Leaves I, Brown GD, Brown AJP, Brock M, Peres da Silva R. CRISPR-based tools for targeted genetic manipulation in pathogenic Sporothrix species. Microbiol Spectr 2023; 11:e0507822. [PMID: 37707447 PMCID: PMC10581184 DOI: 10.1128/spectrum.05078-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 07/11/2023] [Indexed: 09/15/2023] Open
Abstract
Sporothrix brasiliensis is an emerging fungal pathogen frequently associated with zoonotic transmission of sporotrichosis by contaminated cats. Within 25 years, the disease has spread not only throughout Brazil but now to neighboring countries in Latin America. Thermo-dimorphism, melanin, glycans, adhesins, and secreted vesicles have been associated with the ability of Sporothrix species to cause disease in the mammalian host. Although certain virulence factors have been proposed as potential determinants for sporotrichosis, the scarcity of molecular tools for performing reverse genetics in Sporothrix has significantly impeded the dissection of mechanisms underlying the disease. Here, we demonstrate that PEG-mediated protoplast transformation is a powerful method for heterologous gene expression in S. brasiliensis, S. schenckii, and S. chilensis. Combined with CRISPR/Cas9 gene editing, this transformation protocol enabled the deletion of the putative DHN-melanin synthase gene pks1, which is a proposed virulence factor of Sporothrix species. To improve in locus integration of deletion constructs, we deleted the KU80 homolog that is critical for non-homologous end-joining DNA repair. The use of Δku80 strains from S. brasiliensis enhanced homologous-directed repair during transformation resulting in increased targeted gene deletion in combination with CRISPR/Cas9. In conclusion, our CRISPR/Cas9-based transformation protocol provides an efficient tool for targeted gene manipulation in Sporothrix species. IMPORTANCE Sporotrichosis caused by Sporothrix brasiliensis is a disease that requires long periods of treatment and is rapidly spreading across Latin America. The virulence of this fungus and the surge of atypical and more severe presentations of the disease raise the need for an understanding of the molecular mechanisms underlying sporotrichosis, as well as the development of better diagnostics and antifungal therapies. By developing molecular tools for accurate genetic manipulation in Sporothrix, this study addresses the paucity of reliable and reproducible tools for stable genetic engineering of Sporothrix species, which has represented a major obstacle for studying the virulence determinants and their roles in the establishment of sporotrichosis.
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Affiliation(s)
- Remi Hatinguais
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | - Ian Leaves
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | - Gordon D. Brown
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | - Alistair J. P. Brown
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | - Matthias Brock
- Fungal Biology Group, School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Roberta Peres da Silva
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
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Larcombe DE, Bohovych IM, Pradhan A, Ma Q, Hickey E, Leaves I, Cameron G, Avelar GM, de Assis LJ, Childers DS, Bain JM, Lagree K, Mitchell AP, Netea MG, Erwig LP, Gow NAR, Brown AJP. Glucose-enhanced oxidative stress resistance-A protective anticipatory response that enhances the fitness of Candida albicans during systemic infection. PLoS Pathog 2023; 19:e1011505. [PMID: 37428810 PMCID: PMC10358912 DOI: 10.1371/journal.ppat.1011505] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 07/20/2023] [Accepted: 06/22/2023] [Indexed: 07/12/2023] Open
Abstract
Most microbes have developed responses that protect them against stresses relevant to their niches. Some that inhabit reasonably predictable environments have evolved anticipatory responses that protect against impending stresses that are likely to be encountered in their niches-termed "adaptive prediction". Unlike yeasts such as Saccharomyces cerevisiae, Kluyveromyces lactis and Yarrowia lipolytica and other pathogenic Candida species we examined, the major fungal pathogen of humans, Candida albicans, activates an oxidative stress response following exposure to physiological glucose levels before an oxidative stress is even encountered. Why? Using competition assays with isogenic barcoded strains, we show that "glucose-enhanced oxidative stress resistance" phenotype enhances the fitness of C. albicans during neutrophil attack and during systemic infection in mice. This anticipatory response is dependent on glucose signalling rather than glucose metabolism. Our analysis of C. albicans signalling mutants reveals that the phenotype is not dependent on the sugar receptor repressor pathway, but is modulated by the glucose repression pathway and down-regulated by the cyclic AMP-protein kinase A pathway. Changes in catalase or glutathione levels do not correlate with the phenotype, but resistance to hydrogen peroxide is dependent on glucose-enhanced trehalose accumulation. The data suggest that the evolution of this anticipatory response has involved the recruitment of conserved signalling pathways and downstream cellular responses, and that this phenotype protects C. albicans from innate immune killing, thereby promoting the fitness of C. albicans in host niches.
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Affiliation(s)
- Daniel E. Larcombe
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
- Medical Research Council Centre for Medical Mycology, University of Exeter, School of Biosciences, Geoffrey Pope Building, Exeter, United Kingdom
| | - Iryna M. Bohovych
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Arnab Pradhan
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
- Medical Research Council Centre for Medical Mycology, University of Exeter, School of Biosciences, Geoffrey Pope Building, Exeter, United Kingdom
| | - Qinxi Ma
- Medical Research Council Centre for Medical Mycology, University of Exeter, School of Biosciences, Geoffrey Pope Building, Exeter, United Kingdom
| | - Emer Hickey
- Medical Research Council Centre for Medical Mycology, University of Exeter, School of Biosciences, Geoffrey Pope Building, Exeter, United Kingdom
| | - Ian Leaves
- Medical Research Council Centre for Medical Mycology, University of Exeter, School of Biosciences, Geoffrey Pope Building, Exeter, United Kingdom
| | - Gary Cameron
- Rowett Institute, School of Medicine Medical Sciences & Nutrition, University of Aberdeen, Aberdeen, United Kingdom
| | - Gabriela M. Avelar
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Leandro J. de Assis
- Medical Research Council Centre for Medical Mycology, University of Exeter, School of Biosciences, Geoffrey Pope Building, Exeter, United Kingdom
| | - Delma S. Childers
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Judith M. Bain
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Katherine Lagree
- Department of Microbiology, Biosciences Building, University of Georgia, Athens, Georgia, United States of America
| | - Aaron P. Mitchell
- Department of Microbiology, Biosciences Building, University of Georgia, Athens, Georgia, United States of America
| | - Mihai G. Netea
- Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, Netherlands
- Department for Immunology & Metabolism, Life and Medical Sciences Institute, University of Bonn, Bonn, Germany
| | - Lars P. Erwig
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
- Johnson-Johnson Innovation, EMEA Innovation Centre, One Chapel Place, London, United Kingdom
| | - Neil A. R. Gow
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
- Medical Research Council Centre for Medical Mycology, University of Exeter, School of Biosciences, Geoffrey Pope Building, Exeter, United Kingdom
| | - Alistair J. P. Brown
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
- Medical Research Council Centre for Medical Mycology, University of Exeter, School of Biosciences, Geoffrey Pope Building, Exeter, United Kingdom
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de Assis LJ, Bain JM, Liddle C, Leaves I, Hacker C, Peres da Silva R, Yuecel R, Bebes A, Stead D, Childers DS, Pradhan A, Mackenzie K, Lagree K, Larcombe DE, Ma Q, Avelar GM, Netea MG, Erwig LP, Mitchell AP, Brown GD, Gow NAR, Brown AJP. Nature of β-1,3-Glucan-Exposing Features on Candida albicans Cell Wall and Their Modulation. mBio 2022; 13:e0260522. [PMID: 36218369 PMCID: PMC9765427 DOI: 10.1128/mbio.02605-22] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 09/19/2022] [Indexed: 01/15/2023] Open
Abstract
Candida albicans exists as a commensal of mucosal surfaces and the gastrointestinal tract without causing pathology. However, this fungus is also a common cause of mucosal and systemic infections when antifungal immune defenses become compromised. The activation of antifungal host defenses depends on the recognition of fungal pathogen-associated molecular patterns (PAMPs), such as β-1,3-glucan. In C. albicans, most β-1,3-glucan is present in the inner cell wall, concealed by the outer mannan layer, but some β-1,3-glucan becomes exposed at the cell surface. In response to host signals, such as lactate, C. albicans induces the Xog1 exoglucanase, which shaves exposed β-1,3-glucan from the cell surface, thereby reducing phagocytic recognition. We show here that β-1,3-glucan is exposed at bud scars and punctate foci on the lateral wall of yeast cells, that this exposed β-1,3-glucan is targeted during phagocytic attack, and that lactate-induced masking reduces β-1,3-glucan exposure at bud scars and at punctate foci. β-1,3-Glucan masking depends upon protein kinase A (PKA) signaling. We reveal that inactivating PKA, or its conserved downstream effectors, Sin3 and Mig1/Mig2, affects the amounts of the Xog1 and Eng1 glucanases in the C. albicans secretome and modulates β-1,3-glucan exposure. Furthermore, perturbing PKA, Sin3, or Mig1/Mig2 attenuates the virulence of lactate-exposed C. albicans cells in Galleria. Taken together, the data are consistent with the idea that β-1,3-glucan masking contributes to Candida pathogenicity. IMPORTANCE Microbes that coexist with humans have evolved ways of avoiding or evading our immunological defenses. These include the masking by these microbes of their "pathogen-associated molecular patterns" (PAMPs), which are recognized as "foreign" and used to activate protective immunity. The commensal fungus Candida albicans masks the proinflammatory PAMP β-1,3-glucan, which is an essential component of its cell wall. Most of this β-1,3-glucan is hidden beneath an outer layer of the cell wall on these microbes, but some can become exposed at the fungal cell surface. Using high-resolution confocal microscopy, we examine the nature of the exposed β-1,3-glucan at C. albicans bud scars and at punctate foci on the lateral cell wall, and we show that these features are targeted by innate immune cells. We also reveal that downstream effectors of protein kinase A (Mig1/Mig2, Sin3) regulate the secretion of major glucanases, modulate the levels of β-1,3-glucan exposure, and influence the virulence of C. albicans in an invertebrate model of systemic infection. Our data support the view that β-1,3-glucan masking contributes to immune evasion and the virulence of a major fungal pathogen of humans.
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Affiliation(s)
- Leandro José de Assis
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | - Judith M. Bain
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Corin Liddle
- Bioimaging Unit, University of Exeter, Exeter, United Kingdom
| | - Ian Leaves
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | | | - Roberta Peres da Silva
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | - Raif Yuecel
- Exeter Centre for Cytomics, University of Exeter, Exeter, United Kingdom
| | - Attila Bebes
- Exeter Centre for Cytomics, University of Exeter, Exeter, United Kingdom
| | - David Stead
- Aberdeen Proteomics Facility, Rowett Institute, University of Aberdeen, Aberdeen, United Kingdom
| | - Delma S. Childers
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Arnab Pradhan
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | - Kevin Mackenzie
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Katherine Lagree
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Daniel E. Larcombe
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | - Qinxi Ma
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | - Gabriela Mol Avelar
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Mihai G. Netea
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen, Netherlands
- Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, Netherlands
- Department for Immunology & Metabolism, Life and Medical Sciences Institute (LIMES), University of Bonn, Bonn, Germany
| | - Lars P. Erwig
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
- Johnson-Johnson Innovation, EMEA Innovation Centre, London, United Kingdom
| | - Aaron P. Mitchell
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Gordon D. Brown
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | - Neil A. R. Gow
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | - Alistair J. P. Brown
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
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Pradhan A, Ma Q, Hickey E, Avelar G, Larcombe D, Bain J, Childers D, Dambuza I, Leaves I, de Assis LJ, Netea M, Brown G, Erwig L, Gow NAR, Brown AJP. S9.4c Diverse environmental inputs mediate changes in β-glucan exposure at the Candida albicans cell surface thereby influencing tissue colonisation during systemic infection. Med Mycol 2022. [PMCID: PMC9511523 DOI: 10.1093/mmy/myac072.s9.4c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
S9.4 Free oral presentations (late breaking), September 23, 2022, 4:45 PM - 6:15 PM Candida albicans adaptation to host niches affects the exposure of key pathogen-associated molecular patterns (PAMPs) on its cell surface and, consequently, the detection of C. albicans cells by the immune system. Focusing on β-(1,3)-glucan, we screened for host inputs that influence the exposure of this immune-stimulatory PAMP on the C. albicans cell surface. We used a combination of fluorescent microscopy, flow cytometry, and cytokine assays, and then analyzed certain conditions in more detail using transmission electron microscopy and time-lapse video microscopy of C. albicans-phagocyte interactions. We found that some nutrients, micronutrient limitation, stresses, and antifungal drugs trigger β-glucan masking, whereas other inputs, such as nitrogen sources and quorum sensing molecules, exert limited effects on β-glucan exposure. In particular, host- or bacterial-derived L-lactate, hypoxia, or iron limitation induce β-glucan masking, and this leads to attenuation of phagocytic responses [Nature Micro 2, 16 238; mBio 9, e01318-18; Nature Comms 10, 5315]. Lactate signals through Gpr1 to activate Crz1 in a calcineurin-independent manner, whereas hypoxia signals via mitochondrial ROS, and iron limitation signals through Ftr1 and Sef1. β-glucan masking also depends upon downstream signaling via the cAMP-PKA pathway. We conclude that C. albicans has evolved to exploit a range of specific host-derived signals to modulate the exposure of a major PAMP at its cell surface in an attempt to evade phagocytic uptake. Using barcode-sequencing in direct competition assays in vivo, we showed that preadaptation to specific β-glucan masking signals affects the ability of this fungus to colonize particular tissues during systemic infection in a murine model. This reinforces the view that β-glucan masking promotes C. albicans infection.
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Affiliation(s)
- Arnab Pradhan
- MRC Centre for Medical Mycology , University of Exeter, Exeter , United Kingdom
| | - Qinxi Ma
- MRC Centre for Medical Mycology , University of Exeter, Exeter , United Kingdom
| | - Emer Hickey
- MRC Centre for Medical Mycology , University of Exeter, Exeter , United Kingdom
| | - Gabriela Avelar
- Institute of Medical Science , University of Aberdeen, Aberdeen , United Kingdom
| | - Daniel Larcombe
- MRC Centre for Medical Mycology , University of Exeter, Exeter , United Kingdom
| | - Judith Bain
- Institute of Medical Science , University of Aberdeen, Aberdeen , United Kingdom
| | - Delma Childers
- Institute of Medical Science , University of Aberdeen, Aberdeen , United Kingdom
| | - Ivy Dambuza
- MRC Centre for Medical Mycology , University of Exeter, Exeter , United Kingdom
| | - Ian Leaves
- MRC Centre for Medical Mycology , University of Exeter, Exeter , United Kingdom
| | | | - Mihai Netea
- Department of Internal Medicine and Radboud Centre for Infectious Diseases , Radboud University Medical Centre, Nijmegen , Netherlands
- Department for Immunology & Metabolism , Life and Medical Sciences Institute (LIMES), University of Bonn, Bonn , Germany
| | - Gordon Brown
- MRC Centre for Medical Mycology , University of Exeter, Exeter , United Kingdom
| | - Lars Erwig
- Institute of Medical Science , University of Aberdeen, Aberdeen , United Kingdom
- Johnson-Johnson Innovation , EMEA Innovation Centre, One Chapel Place, London , United Kingdom
| | - Neil A. R. Gow
- MRC Centre for Medical Mycology , University of Exeter, Exeter , United Kingdom
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Pradhan A, Ma Q, de Assis LJ, Leaves I, Larcombe DE, Rodriguez Rondon AV, Nev OA, Brown AJP. Anticipatory Stress Responses and Immune Evasion in Fungal Pathogens. Trends Microbiol 2021; 29:416-427. [PMID: 33059975 DOI: 10.1016/j.tim.2020.09.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 09/10/2020] [Accepted: 09/22/2020] [Indexed: 12/17/2022]
Abstract
In certain niches, microbes encounter environmental challenges that are temporally linked. In such cases, microbial fitness is enhanced by the evolution of anticipatory responses where the initial challenge simultaneously activates pre-emptive protection against the second impending challenge. The accumulation of anticipatory responses in domesticated yeasts, which have been termed 'adaptive prediction', has led to the emergence of 'core stress responses' that provide stress cross-protection. Protective anticipatory responses also seem to be common in fungal pathogens of humans. These responses reflect the selective pressures that these fungi have faced relatively recently in their evolutionary history. Consequently, some pathogens have evolved 'core environmental responses' which exploit host signals to trigger immune evasion strategies that protect them against imminent immune attack.
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Affiliation(s)
- Arnab Pradhan
- Medical Research Council Centre for Medical Mycology, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK
| | - Qinxi Ma
- Medical Research Council Centre for Medical Mycology, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK
| | - Leandro J de Assis
- Medical Research Council Centre for Medical Mycology, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK
| | - Ian Leaves
- Medical Research Council Centre for Medical Mycology, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK
| | - Daniel E Larcombe
- Medical Research Council Centre for Medical Mycology, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK
| | - Alejandra V Rodriguez Rondon
- Medical Research Council Centre for Medical Mycology, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK
| | - Olga A Nev
- Medical Research Council Centre for Medical Mycology, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK
| | - Alistair J P Brown
- Medical Research Council Centre for Medical Mycology, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK.
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White RR, Lin C, Leaves I, Castro IG, Metz J, Bateman BC, Botchway SW, Ward AD, Ashwin P, Sparkes I. Miro2 tethers the ER to mitochondria to promote mitochondrial fusion in tobacco leaf epidermal cells. Commun Biol 2020; 3:161. [PMID: 32246085 PMCID: PMC7125145 DOI: 10.1038/s42003-020-0872-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Accepted: 02/25/2020] [Indexed: 12/19/2022] Open
Abstract
Mitochondria are highly pleomorphic, undergoing rounds of fission and fusion. Mitochondria are essential for energy conversion, with fusion favouring higher energy demand. Unlike fission, the molecular components involved in mitochondrial fusion in plants are unknown. Here, we show a role for the GTPase Miro2 in mitochondria interaction with the ER and its impacts on mitochondria fusion and motility. Mutations in AtMiro2's GTPase domain indicate that the active variant results in larger, fewer mitochondria which are attached more readily to the ER when compared with the inactive variant. These results are contrary to those in metazoans where Miro predominantly controls mitochondrial motility, with additional GTPases affecting fusion. Synthetically controlling mitochondrial fusion rates could fundamentally change plant physiology by altering the energy status of the cell. Furthermore, altering tethering to the ER could have profound effects on subcellular communication through altering the exchange required for pathogen defence.
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Affiliation(s)
| | - Congping Lin
- Department of Mathematics, Harrison Building, University of Exeter, Exeter, EX4 4QF, UK
- Center for Mathematical Sciences, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Lab of Engineering Modeling and Scientific Computing, Huazhong University of Science and Technology, Wuhan, China
| | - Ian Leaves
- Biosciences, CLES, Exeter University, Exeter, EX4 4QD, UK
| | - Inês G Castro
- Biosciences, CLES, Exeter University, Exeter, EX4 4QD, UK
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Jeremy Metz
- Biosciences, CLES, Exeter University, Exeter, EX4 4QD, UK
| | - Benji C Bateman
- Central Laser Facility, Science and Technology Facilities Council, Research Complex at Harwell, Didcot, Oxon, OX11 0FA, UK
| | - Stanley W Botchway
- Central Laser Facility, Science and Technology Facilities Council, Research Complex at Harwell, Didcot, Oxon, OX11 0FA, UK
| | - Andrew D Ward
- Central Laser Facility, Science and Technology Facilities Council, Research Complex at Harwell, Didcot, Oxon, OX11 0FA, UK
| | - Peter Ashwin
- Department of Mathematics, Harrison Building, University of Exeter, Exeter, EX4 4QF, UK
| | - Imogen Sparkes
- Biosciences, CLES, Exeter University, Exeter, EX4 4QD, UK.
- School of Biological Sciences, University of Bristol, Bristol Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK.
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