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Katsipoulaki M, Stappers MHT, Malavia-Jones D, Brunke S, Hube B, Gow NAR. Candida albicans and Candida glabrata: global priority pathogens. Microbiol Mol Biol Rev 2024:e0002123. [PMID: 38832801 DOI: 10.1128/mmbr.00021-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2024] Open
Abstract
SUMMARYA significant increase in the incidence of Candida-mediated infections has been observed in the last decade, mainly due to rising numbers of susceptible individuals. Recently, the World Health Organization published its first fungal pathogen priority list, with Candida species listed in medium, high, and critical priority categories. This review is a synthesis of information and recent advances in our understanding of two of these species-Candida albicans and Candida glabrata. Of these, C. albicans is the most common cause of candidemia around the world and is categorized as a critical priority pathogen. C. glabrata is considered a high-priority pathogen and has become an increasingly important cause of candidemia in recent years. It is now the second most common causative agent of candidemia in many geographical regions. Despite their differences and phylogenetic divergence, they are successful as pathogens and commensals of humans. Both species can cause a broad variety of infections, ranging from superficial to potentially lethal systemic infections. While they share similarities in certain infection strategies, including tissue adhesion and invasion, they differ significantly in key aspects of their biology, interaction with immune cells, host damage strategies, and metabolic adaptations. Here we provide insights on key aspects of their biology, epidemiology, commensal and pathogenic lifestyles, interactions with the immune system, and antifungal resistance.
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Affiliation(s)
- Myrto Katsipoulaki
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, Jena, Germany
| | - Mark H T Stappers
- MRC Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | - Dhara Malavia-Jones
- MRC Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | - 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
| | - Neil A R Gow
- MRC Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
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2
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Lindemann-Perez E, Perez JC. Candida albicans natural diversity: a resource to dissect fungal commensalism and pathogenesis. Curr Opin Microbiol 2024; 80:102493. [PMID: 38833793 DOI: 10.1016/j.mib.2024.102493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 05/02/2024] [Accepted: 05/22/2024] [Indexed: 06/06/2024]
Abstract
Candida albicans is a ubiquitous fungus of humans. It is not only a component of the oral and intestinal microbiota of most healthy adults but also a major cause of mucosal disorders and life-threatening disseminated infections. Until recently, research on the biology and pathogenesis of the fungus was largely based on a single clinical isolate. We review investigations that have started to dissect a diverse set of C. albicans strains. Using different approaches to leverage the species' phenotypic and/or genetic diversity, these studies illuminate the wide range of interactions between fungus and host. While connecting genetic variants to phenotypes of interest remains challenging, research on C. albicans' natural diversity is central to understand fungal commensalism and pathogenesis.
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Affiliation(s)
- Elena Lindemann-Perez
- Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, USA
| | - J Christian Perez
- Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, USA.
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3
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McFadden MJ, Reynolds MB, Michmerhuizen BC, Ólafsson EB, Anderson FM, Schultz TL, O’Riordan MX, O’Meara TR. Non-canonical activation of IRE1α during Candida albicans infection enhances macrophage fungicidal activity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.02.560560. [PMID: 37873171 PMCID: PMC10592910 DOI: 10.1101/2023.10.02.560560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
While the canonical function of IRE1α is to detect misfolded proteins and activate the unfolded protein response (UPR) to maintain cellular homeostasis, microbial pathogens can also activate IRE1α, which modulates innate immunity and infection outcomes. However, how infection activates IRE1α and its associated inflammatory functions have not been fully elucidated. Recognition of microbe-associated molecular patterns can activate IRE1α, but it is unclear whether this depends on protein misfolding. Here, we report that a common and deadly fungal pathogen, Candida albicans, activates macrophage IRE1α through C-type lectin receptor signaling, reinforcing a role for IRE1α as a central regulator of host responses to infection by a broad range of pathogens. This activation did not depend on protein misfolding in response to C. albicans infection. Moreover, lipopolysaccharide treatment was also able to activate IRE1α prior to protein misfolding, suggesting that pathogen-mediated activation of IRE1α occurs through non-canonical mechanisms. During C. albicans infection, we observed that IRE1α activity promotes phagolysosomal fusion that supports the fungicidal activity of macrophages. Consequently, macrophages lacking IRE1α activity displayed inefficient phagosome maturation, enabling C. albicans to lyse the phagosome, evade fungal killing, and drive aberrant inflammatory cytokine production. Mechanistically, we show that IRE1α activity supports phagosomal calcium flux after phagocytosis of C. albicans, which is crucial for phagosome maturation. Importantly, deletion of IRE1α activity decreased the fungicidal activity of phagocytes in vivo during systemic C. albicans infection. Together, these data provide mechanistic insight for the non-canonical activation of IRE1α during infection, and reveal central roles for IRE1α in macrophage antifungal responses.
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Affiliation(s)
- Michael J. McFadden
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Mack B. Reynolds
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109, USA
| | | | - Einar B. Ólafsson
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Faith M. Anderson
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Tracey L. Schultz
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Mary X.D. O’Riordan
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Teresa R. O’Meara
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109, USA
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4
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Iracane E, Arias-Sardá C, Maufrais C, Ene IV, d’Enfert C, Buscaino A. Identification of an active RNAi pathway in Candida albicans. Proc Natl Acad Sci U S A 2024; 121:e2315926121. [PMID: 38625945 PMCID: PMC11047096 DOI: 10.1073/pnas.2315926121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 03/08/2024] [Indexed: 04/18/2024] Open
Abstract
RNA interference (RNAi) is a fundamental regulatory pathway with a wide range of functions, including regulation of gene expression and maintenance of genome stability. Although RNAi is widespread in the fungal kingdom, well-known species, such as the model yeast Saccharomyces cerevisiae, have lost the RNAi pathway. Until now evidence has been lacking for a fully functional RNAi pathway in Candida albicans, a human fungal pathogen considered critically important by the World Health Organization. Here, we demonstrated that the widely used C. albicans reference strain (SC5314) contains an inactivating missense mutation in the gene encoding for the central RNAi component Argonaute. In contrast, most other C. albicans isolates contain a canonical Argonaute protein predicted to be functional and RNAi-active. Indeed, using high-throughput small and long RNA sequencing combined with seamless CRISPR/Cas9-based gene editing, we demonstrate that an active C. albicans RNAi machinery represses expression of subtelomeric gene families. Thus, an intact and functional RNAi pathway exists in C. albicans, highlighting the importance of using multiple reference strains when studying this dangerous pathogen.
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Affiliation(s)
- Elise Iracane
- Kent Fungal Group, School of Biosciences, Division of Natural Sciences, University of Kent, CanterburyCT2 7NZ, United Kingdom
| | - Cristina Arias-Sardá
- Kent Fungal Group, School of Biosciences, Division of Natural Sciences, University of Kent, CanterburyCT2 7NZ, United Kingdom
| | - Corinne Maufrais
- Institut Pasteur, Université Paris Cité, Bioinformatic Hub, ParisF-75015, France
| | - Iuliana V. Ene
- Institut Pasteur, Université Paris Cité, Fungal Heterogeneity Group, ParisF-75015, France
| | - Christophe d’Enfert
- Institut Pasteur, Université Paris Cité, Institut national de recherche pour l’agriculture, l’alimentation et l’environnement USC2019, Fungal Biology and Pathogenicity Unit, ParisF-75015, France
| | - Alessia Buscaino
- Kent Fungal Group, School of Biosciences, Division of Natural Sciences, University of Kent, CanterburyCT2 7NZ, United Kingdom
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5
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Brar NK, Dhariwal A, Åmdal HA, Junges R, Salvadori G, Baker JL, Edlund A, Petersen FC. Exploring ex vivo biofilm dynamics: consequences of low ampicillin concentrations on the human oral microbiome. NPJ Biofilms Microbiomes 2024; 10:37. [PMID: 38565843 PMCID: PMC10987642 DOI: 10.1038/s41522-024-00507-7] [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: 08/28/2023] [Accepted: 03/20/2024] [Indexed: 04/04/2024] Open
Abstract
Prolonged exposure to antibiotics at low concentration can promote processes associated with bacterial biofilm formation, virulence and antibiotic resistance. This can be of high relevance in microbial communities like the oral microbiome, where commensals and pathogens share a common habitat and where the total abundance of antibiotic resistance genes surpasses the abundance in the gut. Here, we used an ex vivo model of human oral biofilms to investigate the impact of ampicillin on biofilm viability. The ecological impact on the microbiome and resistome was investigated using shotgun metagenomics. The results showed that low concentrations promoted significant shifts in microbial taxonomic profile and could enhance biofilm viability by up to 1 to 2-log. For the resistome, low concentrations had no significant impact on antibiotic resistance gene (ARG) diversity, while ARG abundance decreased by up to 84%. A positive correlation was observed between reduced microbial diversity and reduced ARG abundance. The WHO priority pathogens Streptococcus pneumoniae and Staphylococcus aureus were identified in some of the samples, but their abundance was not significantly altered by ampicillin. Most of the antibiotic resistance genes that increased in abundance in the ampicillin group were associated with streptococci, including Streptococcus mitis, a well-known potential donor of ARGs to S. pneumoniae. Overall, the results highlight the potential of using the model to further our understanding of ecological and evolutionary forces driving antimicrobial resistance in oral microbiomes.
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Affiliation(s)
- N K Brar
- Institute of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway
| | - A Dhariwal
- Institute of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway
| | - H A Åmdal
- Institute of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway
| | - R Junges
- Institute of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway
| | - G Salvadori
- Institute of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway
| | - J L Baker
- Department of Oral Rehabilitation & Biosciences, Oregon Health & Science University, Portland, OR, USA
- Microbial and Environmental Genomics, J. Craig Venter Institute, La Jolla, CA, USA
- Department of Pediatrics, UC San Diego School of Medicine, La Jolla, CA, USA
| | - A Edlund
- Microbial and Environmental Genomics, J. Craig Venter Institute, La Jolla, CA, USA
- Department of Pediatrics, UC San Diego School of Medicine, La Jolla, CA, USA
| | - F C Petersen
- Institute of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway.
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6
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Wakade RS, Wellington M, Krysan DJ. The role of the C. albicans transcriptional repressor NRG1 during filamentation and disseminated candidiasis is strain dependent. mSphere 2024; 9:e0078523. [PMID: 38376205 PMCID: PMC10964420 DOI: 10.1128/msphere.00785-23] [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: 12/14/2023] [Accepted: 01/26/2024] [Indexed: 02/21/2024] Open
Abstract
Candida albicans is one of the most common causes of superficial and invasive fungal diseases in humans. Its ability to cause disease is closely linked to its ability to undergo a morphological transition from budding yeast to filamentous forms (hyphae and pseudohyphae). The extent to which C. albicans strains isolated from patients undergo filamentation varies significantly. In addition, the filamentation phenotypes of mutants involving transcription factors that positively regulate hyphal morphogenesis can also vary from strain to strain. Here, we characterized the virulence, in vitro and in vivo filamentation, and in vitro and in vivo hypha-associated gene expression profiles for four poorly filamenting C. albicans isolates and their corresponding deletion mutants of the repressor of filamentation NRG1. The two most virulent strains, 57055 and 78048, show robust in vivo filamentation but are predominately yeast phase under in vitro hypha induction; the two low-virulence strains (94015 and 78042) do not undergo filamentation well under either condition. In vitro, deletion of NRG1 increases hyphae formation in the SC5314 derivative SN250, but only pseudohyphae are formed in the clinical isolates. Deletion of NRG1 modestly increased the virulence of 78042, which was accompanied by increased expression of hypha-associated genes without an increase in filamentation. Strikingly, deletion of NRG1 in 78048 reduced filamentation in vivo, expression of candidalysin (ECE1), and virulence without dramatically altering establishment of infection. Thus, the function of the conserved repressor NRG1 in C. albicans shows strain-based heterogeneity during infection.IMPORTANCEClinical isolates of the human fungal pathogen Candida albicans show significant variation in their ability to undergo in vitro filamentation and in the function of well-characterized transcriptional regulators of filamentation. Here, we show that Nrg1, a key repressor of filamentation and filament specific gene expression in standard reference strains, has strain-dependent functions, particularly during infection. Most strikingly, loss of NRG1 function can reduce filamentation, hypha-specific gene expression such as the toxin candidalysin, and virulence in some strains. Our data emphasize that the functions of seemingly fundamental and well-conserved transcriptional regulators such as Nrg1 are contextual with respect to both environment and genetic backgrounds.
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Affiliation(s)
- Rohan S. Wakade
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Melanie Wellington
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Damian J. Krysan
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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Santana DJ, Zhao G, O’Meara TR. The many faces of Candida auris: Phenotypic and strain variation in an emerging pathogen. PLoS Pathog 2024; 20:e1012011. [PMID: 38427609 PMCID: PMC10906884 DOI: 10.1371/journal.ppat.1012011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2024] Open
Abstract
Candida auris is an emerging fungal pathogen with unusual evolutionary history-there are multiple distinct phylogeographic clades showing a near simultaneous transition from a currently unknown reservoir to nosocomial pathogen. Each of these clades has experienced different selective pressures over time, likely resulting in selection for genotypes with differential fitness or phenotypic consequences when introduced to new environments. We also observe diversification within clades, providing additional opportunities for phenotypic differences. These differences can have large impacts on pathogenic potential, drug resistance profile, evolutionary trajectory, and transmissibility. In recent years, there have been significant advances in our understanding of strain-specific behavior in other microbes, including bacterial and fungal pathogens, and we have an opportunity to take this strain variation into account when describing aspects of C. auris biology. Here, we critically review the literature to gain insight into differences at both the strain and clade levels in C. auris, focusing on phenotypes associated with clinical disease or transmission. Our goal is to integrate clinical and epidemiological perspectives with molecular perspectives in a way that would be valuable for both audiences. Identifying differences between strains and understanding which phenotypes are strain specific will be crucial for understanding this emerging pathogen, and an important caveat when describing the analysis of a singular isolate.
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Affiliation(s)
- Darian J. Santana
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, Michigan, United States of America
| | - Guolei Zhao
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Teresa R. O’Meara
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
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8
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Woodruff AL, Berman J, Anderson M. Strain background of Candida albicans interacts with SIR2 to alter phenotypic switching. MICROBIOLOGY (READING, ENGLAND) 2024; 170:001444. [PMID: 38446018 PMCID: PMC10999749 DOI: 10.1099/mic.0.001444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 02/15/2024] [Indexed: 03/07/2024]
Abstract
The genetic background between strains of a single species and within a single strain lineage can significantly impact the expression of biological traits. This genetic variation may also reshape epigenetic mechanisms of cell identity and environmental responses that are controlled by interconnected transcriptional networks and chromatin-modifying enzymes. Histone deacetylases, including sirtuins, are critical regulators of chromatin state and have been directly implicated in governing the phenotypic transition between the 'sterile' white state and the mating-competent opaque state in Candida albicans, a common fungal commensal and pathogen of humans. Here, we found that a previously ambiguous role for the sirtuin SIR2 in C. albicans phenotypic switching is likely linked to the genetic background of mutant strains produced in the RM lineage of SC5314. SIR2 mutants in a specific lineage of BWP17 displayed increased frequencies of switching to the opaque state compared to the wild-type. Loss of SIR2 in other SC5314-derived backgrounds, including newly constructed BWP17 sir2Δ/Δ mutants, failed to recapitulate the increased white-opaque switching frequencies observed in the original BWP17 sir2Δ/Δ mutant background. Whole-genome sequencing revealed the presence of multiple imbalanced chromosomes and large loss of heterozygosity tracts that likely interact with SIR2 to increase phenotypic switching in this BWP17 sir2Δ/Δ mutant lineage. These genomic changes are not found in other SC5314-derived sir2Δ/Δ mutants that do not display increased opaque cell formation. Thus, complex karyotypes can emerge during strain construction that modify mutant phenotypes and highlight the importance of validating strain background when interpreting phenotypes.
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Affiliation(s)
- Andrew L. Woodruff
- Department of Microbiology, The Ohio State University, Columbus, OH, 43210, USA
| | - Judith Berman
- Shmunis School of Biomedical and Cancer Research, The George S Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Matthew Anderson
- Department of Microbiology, The Ohio State University, Columbus, OH, 43210, USA
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, 43210, USA
- Department of Medical Genetics, Laboratory of Genetics, University of Wisconsin – Madison, Madison, WI, 53706, USA
- Center for Genomic Science Innovation, University of Wisconsin – Madison, Madison, WI, 53706, USA
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9
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Wakade RS, Wellington M, Krysan DJ. The role of the C. albicans transcriptional repressor NRG1 during filamentation and disseminated candidiasis is strain-dependent. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.15.571891. [PMID: 38168187 PMCID: PMC10760072 DOI: 10.1101/2023.12.15.571891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Candida albicans is one of the most common causes of superficial and invasive fungal disease in humans. Its ability to cause disease has been closely linked to its ability to undergo a morphological transition from budding yeast to filamentous forms (hyphae and pseudohyphae). The ability of C. albicans strains isolated from patients to undergo filamentation varies significantly. In addition, the filamentation phenotypes of mutants involving transcription factors that positively regulate hyphal morphogenesis can also vary from strain to strain. Here, we characterized the virulence, in vitro and in vivo filamentation, and in vitro and in vivo hypha-associated gene expression profiles of four poorly filamenting C. albicans isolates and their corresponding deletion mutants of the repressor of filamentation NRG1. The two most virulent strains, 57055 and 78048, show robust in vivo filamentation while remaining predominately yeast phase exposed to RPMI+10% bovine calf serum at 37°C; the two low virulence strains (94015 and 78042) do not filament well under either condition. Deletion of NRG1 increases hyphae formation in the SC5314 derivative SN250 but only pseudohyphae are formed in the clinical isolates in vivo. Deletion of NRG1 modestly increased the virulence of 78042 which was accompanied by increased expression of hyphae-associated genes without an increase in filamentation. Strikingly, deletion of NRG1 in 78048 reduced filamentation, expression of candidalysin (ECE1) and virulence in vivo without dramatically altering establishment of infection. Thus, the function of NRG1 varies significantly within this set of C. albicans isolates and can actually suppress filamentation in vivo.
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Affiliation(s)
- Rohan S. Wakade
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City IA
| | - Melanie Wellington
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City IA
| | - Damian J. Krysan
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City IA
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City IA
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Glazier VE, Kramara J, Ollinger T, Solis NV, Zarnowski R, Wakade RS, Kim MJ, Weigel GJ, Liang SH, Bennett RJ, Wellington M, Andes DR, Stamnes MA, Filler SG, Krysan DJ. The Candida albicans reference strain SC5314 contains a rare, dominant allele of the transcription factor Rob1 that modulates filamentation, biofilm formation, and oral commensalism. mBio 2023; 14:e0152123. [PMID: 37737633 PMCID: PMC10653842 DOI: 10.1128/mbio.01521-23] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 07/27/2023] [Indexed: 09/23/2023] Open
Abstract
IMPORTANCE Candida albicans is a commensal fungus that colonizes the human oral cavity and gastrointestinal tract but also causes mucosal as well as invasive disease. The expression of virulence traits in C. albicans clinical isolates is heterogeneous and the genetic basis of this heterogeneity is of high interest. The C. albicans reference strain SC5314 is highly invasive and expresses robust filamentation and biofilm formation relative to many other clinical isolates. Here, we show that SC5314 derivatives are heterozygous for the transcription factor Rob1 and contain an allele with a rare gain-of-function SNP that drives filamentation, biofilm formation, and virulence in a model of oropharyngeal candidiasis. These findings explain, in part, the outlier phenotype of the reference strain and highlight the role heterozygosity plays in the strain-to-strain variation of diploid fungal pathogens.
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Affiliation(s)
| | - Juraj Kramara
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Tomye Ollinger
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Norma V. Solis
- Division of Infectious Diseases, Los Angeles Biomedical Research Institute and Harbor-UCLA Medical Center, Torrance, California, USA
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Robert Zarnowski
- Department of Medicine, Section of Infectious Disease, University of Wisconsin, Madison, Wisconsin, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, USA
| | - Rohan S. Wakade
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Min-Ju Kim
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Gabriel J. Weigel
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Shen-Huan Liang
- Department of Molecular Microbiology and Immunology, Brown University, Providence, Rhode Island, USA
| | - Richard J. Bennett
- Department of Molecular Microbiology and Immunology, Brown University, Providence, Rhode Island, USA
| | - Melanie Wellington
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - David R. Andes
- Department of Medicine, Section of Infectious Disease, University of Wisconsin, Madison, Wisconsin, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, USA
| | - Mark A. Stamnes
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Scott G. Filler
- Division of Infectious Diseases, Los Angeles Biomedical Research Institute and Harbor-UCLA Medical Center, Torrance, California, USA
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Damian J. Krysan
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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11
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Zhu W, Zhang H, Dong Q, Song H, Zhao L. Dual wave of neutrophil recruitment determines the outcome of C. albicans infection. Front Cell Infect Microbiol 2023; 13:1239593. [PMID: 37492529 PMCID: PMC10364056 DOI: 10.3389/fcimb.2023.1239593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 06/26/2023] [Indexed: 07/27/2023] Open
Abstract
Candida albicans is a ubiquitous fungus that can cause superficial and systemic infections in humans. Neutrophils play a crucial role in controlling C. albicans infections. When C. albicans enters the bloodstream, it tends to get trapped in capillary vessels. However, the behavior of neutrophils in combating capillary-residing fungi has not been fully characterized. In this study, we used transgenic mice and whole mount imaging to investigate the growth of C. albicans and its interaction with innate immune cells in different organs. We observed that C. albicans rapidly grows hyphae within hours of infection. Following intravenous infection, we observed two waves of neutrophil recruitment, both of which significantly contributed to the elimination of the fungi. The first wave of neutrophils was induced by complement activation and could be prevented by C5aR blockade. Interestingly, we discovered that the fungicidal effect in the lungs was independent of adhesion molecules such as Mac-1, LFA-1, and ICAM-1. However, these molecules played a more significant role in the optimal killing of C. albicans in the kidney. Importantly, the initial difference in killing efficiency resulted in significantly reduced survival in knockout mice lacking these adhesion molecules. We identified a second wave of neutrophil recruitment associated with hyphal growth and tissue damage, which was independent of the aforementioned adhesion molecules. Overall, this study elucidates the dual wave of neutrophil recruitment during C. albicans infection and highlights the importance of early fungal clearance for favorable disease outcomes.
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Affiliation(s)
- Weiwei Zhu
- Department of Cardiovascular Medicine, Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, Guangdong, China
| | - Huifang Zhang
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Qiming Dong
- Department of Internal Medicine, Greater Baltimore Medical Center, Towson, MD, United States
| | - Hongyong Song
- Department of Cardiovascular Medicine, Central Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China
| | - Lin Zhao
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
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12
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Du Toit A. Invasive Candida hidden in plain sight. Nat Rev Microbiol 2023:10.1038/s41579-023-00923-0. [PMID: 37268863 DOI: 10.1038/s41579-023-00923-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
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