1
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Horton MV, Eix EF, Johnson CJ, Dean MEB, Andes BD, Wartman KM, Nett JE. Impact of micafungin on Candida auris β-glucan masking and neutrophil interactions. J Infect Dis 2024:jiae043. [PMID: 38330449 DOI: 10.1093/infdis/jiae043] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 01/16/2024] [Accepted: 01/21/2024] [Indexed: 02/10/2024] Open
Abstract
Invasive fungal pathogen Candida auris has become a public health threat causing outbreaks of high mortality infections. Drug resistance often limits treatment options. For Candida albicans, subinhibitory concentrations of echinocandins unmask immunostimulatory β-glucan, augmenting immunity. Here we analyze the impact of echinocandin treatment of C. auris on β-glucan exposure and human neutrophil interactions. We show subinhibitory concentrations lead to minimal glucan unmasking and only subtle influences on neutrophil functions for the isolates belonging to circulating clades. The data suggest that echinocandin treatment will not largely alter phagocytic responses. Glucan masking pathways appear to differ between C. auris and C. albicans.
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Affiliation(s)
- Mark V Horton
- Department of Medicine, University of Wisconsin-Madison, WI, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, WI, USA
| | - Emily F Eix
- Department of Medicine, University of Wisconsin-Madison, WI, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, WI, USA
| | - Chad J Johnson
- Department of Medicine, University of Wisconsin-Madison, WI, USA
| | - Megan E B Dean
- Department of Medicine, University of Wisconsin-Madison, WI, USA
| | - Brody D Andes
- Department of Medicine, University of Wisconsin-Madison, WI, USA
| | - Kayla M Wartman
- Department of Medicine, University of Wisconsin-Madison, WI, USA
| | - Jeniel E Nett
- Department of Medicine, University of Wisconsin-Madison, WI, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, WI, USA
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2
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Jaromin A, Zarnowski R, Markowski A, Zagórska A, Johnson CJ, Etezadi H, Kihara S, Mota-Santiago P, Nett JE, Boyd BJ, Andes DR. Liposomal formulation of a new antifungal hybrid compound provides protection against Candida auris in the ex vivo skin colonization model. Antimicrob Agents Chemother 2024; 68:e0095523. [PMID: 38092678 PMCID: PMC10777852 DOI: 10.1128/aac.00955-23] [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: 07/30/2023] [Accepted: 10/28/2023] [Indexed: 01/11/2024] Open
Abstract
The newly emerged pathogen, Candida auris, presents a serious threat to public health worldwide. This multidrug-resistant yeast often colonizes and persists on the skin of patients, can easily spread from person to person, and can cause life-threatening systemic infections. New antifungal therapies are therefore urgently needed to limit and control both superficial and systemic C. auris infections. In this study, we designed a novel antifungal agent, PQA-Az-13, that contains a combination of indazole, pyrrolidine, and arylpiperazine scaffolds substituted with a trifluoromethyl moiety. PQA-Az-13 demonstrated antifungal activity against biofilms of a set of 10 different C. auris clinical isolates, representing all four geographical clades distinguished within this species. This compound showed strong activity, with MIC values between 0.67 and 1.25 µg/mL. Cellular proteomics indicated that PQA-Az-13 partially or completely inhibited numerous enzymatic proteins in C. auris biofilms, particularly those involved in both amino acid biosynthesis and metabolism processes, as well as in general energy-producing processes. Due to its hydrophobic nature and limited aqueous solubility, PQA-Az-13 was encapsulated in cationic liposomes composed of soybean phosphatidylcholine (SPC), 1,2-dioleoyloxy-3-trimethylammonium-propane chloride (DOTAP), and N-(carbonyl-methoxypolyethylene glycol-2000)-1,2-distearoyl-sn-glycero-3-phosphoethanolamine, sodium salt (DSPE-PEG 2000), and characterized by biophysical and spectral techniques. These PQA-Az-13-loaded liposomes displayed a mean size of 76.4 nm, a positive charge of +45.0 mV, a high encapsulation efficiency of 97.2%, excellent stability, and no toxicity to normal human dermal fibroblasts. PQA-Az-13 liposomes demonstrated enhanced antifungal activity levels against both C. auris in in vitro biofilms and ex vivo skin colonization models. These initial results suggest that molecules like PQA-Az-13 warrant further study and development.
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Affiliation(s)
- Anna Jaromin
- Department of Lipids and Liposomes, Faculty of Biotechnology, University of Wrocław, Wrocław, Poland
| | - Robert Zarnowski
- Department of Medicine, School of Medicine & Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Medical Microbiology, School of Medicine & Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Adam Markowski
- Department of Lipids and Liposomes, Faculty of Biotechnology, University of Wrocław, Wrocław, Poland
| | - Agnieszka Zagórska
- Department of Medicinal Chemistry, Jagiellonian University Medical College, Cracow, Poland
| | - Chad J. Johnson
- Department of Medicine, University of Wisconsin, Madison, Wisconsin, USA
| | - Haniyeh Etezadi
- Department of Pharmacy, University of Copenhagen, Copenhagen, Denmark
| | - Shinji Kihara
- Department of Pharmacy, University of Copenhagen, Copenhagen, Denmark
| | | | - Jeniel E. Nett
- Department of Medicine, University of Wisconsin, Madison, Wisconsin, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, USA
| | - Ben J. Boyd
- Department of Pharmacy, University of Copenhagen, Copenhagen, Denmark
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), Victoria, Australia
| | - David R. Andes
- Department of Medicine, School of Medicine & Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Medical Microbiology, School of Medicine & Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
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3
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Brown Harding H, Kwaku GN, Reardon CM, Khan NS, Zamith-Miranda D, Zarnowski R, Tam JM, Bohaen CK, Richey L, Mosallanejad K, Crossen AJ, Reedy JL, Ward RA, Vargas-Blanco DA, Basham KJ, Bhattacharyya RP, Nett JE, Mansour MK, van de Veerdonk FL, Kumar V, Kagan JC, Andes DR, Nosanchuk JD, Vyas JM. Candida albicans extracellular vesicles trigger type I IFN signalling via cGAS and STING. Nat Microbiol 2024; 9:95-107. [PMID: 38168615 PMCID: PMC10959075 DOI: 10.1038/s41564-023-01546-0] [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: 12/16/2022] [Accepted: 11/06/2023] [Indexed: 01/05/2024]
Abstract
The host type I interferon (IFN) pathway is a major signature of inflammation induced by the human fungal pathogen, Candida albicans. However, the molecular mechanism for activating this pathway in the host defence against C. albicans remains unknown. Here we reveal that mice lacking cyclic GMP-AMP synthase (cGAS)-stimulator of IFN genes (STING) pathway components had improved survival following an intravenous challenge by C. albicans. Biofilm-associated C. albicans DNA packaged in extracellular vesicles triggers the cGAS-STING pathway as determined by induction of interferon-stimulated genes, IFNβ production, and phosphorylation of IFN regulatory factor 3 and TANK-binding kinase 1. Extracellular vesicle-induced activation of type I IFNs was independent of the Dectin-1/Card9 pathway and did not require toll-like receptor 9. Single nucleotide polymorphisms in cGAS and STING potently altered inflammatory cytokine production in human monocytes challenged by C. albicans. These studies provide insights into the early innate immune response induced by a clinically significant fungal pathogen.
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Affiliation(s)
- Hannah Brown Harding
- Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
- Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Geneva N Kwaku
- Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Christopher M Reardon
- Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Nida S Khan
- Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Daniel Zamith-Miranda
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA
- Division of Infectious Diseases, Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Robert Zarnowski
- Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA
- Department of Microbiology and Immunology, University of Wisconsin Madison, Madison, WI, USA
| | - Jenny M Tam
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - Collins K Bohaen
- Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Lauren Richey
- Tufts Comparative Medicine Services, Tufts University, Boston, MA, USA
| | - Kenta Mosallanejad
- Division of Gastroenterology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Arianne J Crossen
- Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Jennifer L Reedy
- Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
- Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Rebecca A Ward
- Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Diego A Vargas-Blanco
- Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
- Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Kyle J Basham
- Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Roby P Bhattacharyya
- Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
- Department of Medicine, Harvard Medical School, Boston, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Jeniel E Nett
- Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA
- Department of Microbiology and Immunology, University of Wisconsin Madison, Madison, WI, USA
| | - Michael K Mansour
- Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
- Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Frank L van de Veerdonk
- Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Vinod Kumar
- Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, the Netherlands
- University Medical Center Groningen, Department of Genetics, University of Groningen, Groningen, the Netherlands
- Nitte University Centre for Science Education and Research, Medical Sciences Complex, Mangaluru, India
| | - Jonathan C Kagan
- Division of Gastroenterology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - David R Andes
- Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA
- Department of Microbiology and Immunology, University of Wisconsin Madison, Madison, WI, USA
| | - Joshua D Nosanchuk
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA
- Division of Infectious Diseases, Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Jatin M Vyas
- Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA.
- Department of Medicine, Harvard Medical School, Boston, MA, USA.
- Broad Institute of MIT and Harvard, Cambridge, MA, USA.
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4
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Gandra RM, Johnson CJ, Nett JE, Konopka JB. The Candida albicans ζ-crystallin homolog Zta1 promotes resistance to oxidative stress. mSphere 2023; 8:e0050723. [PMID: 38032185 PMCID: PMC10732081 DOI: 10.1128/msphere.00507-23] [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: 08/31/2023] [Accepted: 10/13/2023] [Indexed: 12/01/2023] Open
Abstract
IMPORTANCE Candida albicans is an important human pathogen that can cause lethal systemic infections. The ability of C. albicans to colonize and establish infections is closely tied to its highly adaptable nature and capacity to resist various types of stress, including oxidative stress. Previous studies showed that four C. albicans proteins belonging to the flavodoxin-like protein family of quinone reductases are needed for resistance to quinones and virulence. Therefore, in this study, we examined the role of a distinct type of quinone reductase, Zta1, and found that it acts in conjunction with the flavodoxin-like proteins to protect against oxidative stress.
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Affiliation(s)
- Rafael M. Gandra
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, USA
| | - Chad J. Johnson
- Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jeniel E. Nett
- Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - James B. Konopka
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, USA
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5
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Datta A, Das D, Nett JE, Vyas JM, Lionakis MS, Thangamani S. Differential skin immune responses in mice intradermally infected with Candida auris and Candida albicans. Microbiol Spectr 2023; 11:e0221523. [PMID: 37811989 PMCID: PMC10848846 DOI: 10.1128/spectrum.02215-23] [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: 05/25/2023] [Accepted: 08/22/2023] [Indexed: 10/10/2023] Open
Abstract
IMPORTANCE Candida auris is a globally emerging fungal pathogen that transmits among individuals in hospitals and nursing home residents. Unlike other Candida species, C. auris predominantly colonizes and persists in skin tissue, resulting in outbreaks of nosocomial infections. Understanding the factors that regulate C. auris skin colonization is critical to develop novel preventive and therapeutic approaches against this emerging pathogen. We established a model of intradermal C. auris inoculation in mice and found that mice infected with C. auris elicit less potent innate and adaptive immune responses in the infected skin compared to C. albicans. These findings help explain the clinical observation of persistent C. auris colonization in skin tissue.
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Affiliation(s)
- Abhishek Datta
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, Indiana, USA
| | - Diprasom Das
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, Indiana, USA
| | - Jeniel E. Nett
- Department of Medicine, University of Wisconsin, Madison, Wisconsin, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, USA
| | - Jatin M. Vyas
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Michail S. Lionakis
- Fungal Pathogenesis Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Shankar Thangamani
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Immunology, Inflammation and Infectious Diseases (PI4D), West Lafayette, Indiana, USA
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6
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Horton MV, Holt AM, Nett JE. Mechanisms of pathogenicity for the emerging fungus Candida auris. PLoS Pathog 2023; 19:e1011843. [PMID: 38127686 PMCID: PMC10735027 DOI: 10.1371/journal.ppat.1011843] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023] Open
Abstract
Candida auris recently emerged as an urgent public health threat, causing outbreaks of invasive infections in healthcare settings throughout the world. This fungal pathogen persists on the skin of patients and on abiotic surfaces despite antiseptic and decolonization attempts. The heightened capacity for skin colonization and environmental persistence promotes rapid nosocomial spread. Following skin colonization, C. auris can gain entrance to the bloodstream and deeper tissues, often through a wound or an inserted medical device, such as a catheter. C. auris possesses a variety of virulence traits, including the capacity for biofilm formation, production of adhesins and proteases, and evasion of innate immune responses. In this review, we highlight the interactions of C. auris with the host, emphasizing the intersection of laboratory studies and clinical observations.
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Affiliation(s)
- Mark V. Horton
- Department of Medicine, University of Wisconsin, Madison, Wisconsin, United States of America
- Department of Medical Microbiology & Immunology, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Ashley M. Holt
- Department of Medicine, University of Wisconsin, Madison, Wisconsin, United States of America
- Department of Medical Microbiology & Immunology, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Jeniel E. Nett
- Department of Medicine, University of Wisconsin, Madison, Wisconsin, United States of America
- Department of Medical Microbiology & Immunology, University of Wisconsin, Madison, Wisconsin, United States of America
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7
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Santana DJ, Anku JAE, Zhao G, Zarnowski R, Johnson CJ, Hautau H, Visser ND, Ibrahim AS, Andes D, Nett JE, Singh S, O'Meara TR. A Candida auris-specific adhesin, Scf1 , governs surface association, colonization, and virulence. Science 2023; 381:1461-1467. [PMID: 37769084 DOI: 10.1126/science.adf8972] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [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: 12/05/2022] [Accepted: 08/23/2023] [Indexed: 09/30/2023]
Abstract
Candida auris is an emerging fungal pathogen responsible for health care-associated outbreaks that arise from persistent surface and skin colonization. We characterized the arsenal of adhesins used by C. auris and discovered an uncharacterized adhesin, Surface Colonization Factor (Scf1), and a conserved adhesin, Iff4109, that are essential for the colonization of inert surfaces and mammalian hosts. SCF1 is apparently specific to C. auris, and its expression mediates adhesion to inert and biological surfaces across isolates from all five clades. Unlike canonical fungal adhesins, which function through hydrophobic interactions, Scf1 relies on exposed cationic residues for surface association. SCF1 is required for C. auris biofilm formation, skin colonization, virulence in systemic infection, and colonization of inserted medical devices.
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Affiliation(s)
- Darian J Santana
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
- Department of Epidemiology, University of Michigan, Ann Arbor, MI, USA
| | - Juliet A E Anku
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Accra, Ghana
| | - Guolei Zhao
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Robert Zarnowski
- Department of Medicine, University of Wisconsin, Madison, WI, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI, USA
| | - Chad J Johnson
- Department of Medicine, University of Wisconsin, Madison, WI, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI, USA
| | - Haley Hautau
- Division of Infectious Disease, The Lundquist Institute for Biomedical Innovation at Harbor-University of California, Los Angeles Medical Center, Torrance, CA, USA
| | - Noelle D Visser
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Ashraf S Ibrahim
- Division of Infectious Disease, The Lundquist Institute for Biomedical Innovation at Harbor-University of California, Los Angeles Medical Center, Torrance, CA, USA
- David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - David Andes
- Department of Medicine, University of Wisconsin, Madison, WI, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI, USA
| | - Jeniel E Nett
- Department of Medicine, University of Wisconsin, Madison, WI, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI, USA
| | - Shakti Singh
- Division of Infectious Disease, The Lundquist Institute for Biomedical Innovation at Harbor-University of California, Los Angeles Medical Center, Torrance, CA, USA
- David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Teresa R O'Meara
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
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8
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Gandra RM, Johnson CJ, Nett JE, Konopka JB. The Candida albicans ζ-crystallin homolog Zta1 promotes resistance to oxidative stress. bioRxiv 2023:2023.09.05.556406. [PMID: 37732195 PMCID: PMC10508745 DOI: 10.1101/2023.09.05.556406] [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] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
The fungal pathogen Candida albicans is capable of causing lethal infections in humans. Its pathogenic potential is due in part to the ability to resist various stress conditions in the host, including oxidative stress. Recent studies showed that a family of four flavodoxin-like proteins (Pst1, Pst2, Pst3, Ycp4) that function as quinone reductases promotes resistance to oxidation and is needed for virulence. Therefore, in this study Zta1 was examined because it belongs to a structurally distinct family of quinone reductases that are highly conserved in eukaryotes and have been called the ζ-crystallins. The levels of Zta1 in C. albicans rapidly increased after exposure to oxidants, consistent with a role in resisting oxidative stress. Accumulation of reactive oxygen species was significantly higher in cells lacking ZTA1 upon exposure to quinones and other oxidants. Furthermore, deletion of ZTA1 in a mutant lacking the four flavodoxin-like proteins, resulted in further increased susceptibility to quinones, indicating that these distinct quinone reductases work in combination. These results demonstrate that Zta1 contributes to C. albicans survival after exposure to oxidative conditions, which increases the understanding of how C. albicans resists stressful conditions in the host.
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Affiliation(s)
- Rafael M. Gandra
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, United States of America
| | | | - Jeniel E. Nett
- University of Wisconsin-Madison, Department of Medicine
- University of Wisconsin-Madison, Department of Medical Microbiology & Immunology
| | - James B. Konopka
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, United States of America
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9
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Beattie SR, Esan T, Zarnowski R, Eix E, Nett JE, Andes DR, Hagen T, Krysan DJ. Novel Keto-Alkyl-Pyridinium Antifungal Molecules Active in Models of In Vivo Candida albicans Vascular Catheter Infection and Ex Vivo Candida auris Skin Colonization. Antimicrob Agents Chemother 2023; 67:e0008123. [PMID: 37097144 PMCID: PMC10190616 DOI: 10.1128/aac.00081-23] [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: 01/17/2023] [Accepted: 03/10/2023] [Indexed: 04/26/2023] Open
Abstract
New antifungal therapies are needed for both systemic, invasive infections in addition to superficial infections of mucosal and skin surfaces as well as biofilms associated with medical devices. The resistance of biofilm and biofilm-like growth phases of fungi contributes to the poor efficacy of systemic therapies to nonsystemic infections. Here, we describe the identification and characterization of a novel keto-alkyl-pyridinium scaffold with broad spectrum activity (2 to 16 μg/mL) against medically important yeasts and molds, including clinical isolates resistant to azoles and/or echinocandins. Furthermore, these keto-alkyl-pyridinium agents retain substantial activity against biofilm phase yeast and have direct activity against hyphal A. fumigatus. Although their toxicity precludes use in systemic infections, we found that the keto-alkyl-pyridinium molecules reduce Candida albicans fungal burden in a rat model of vascular catheter infection and reduce Candida auris colonization in a porcine ex vivo model. These initial preclinical data suggest that molecules of this class may warrant further study and development for nonsystemic applications.
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Affiliation(s)
- Sarah R. Beattie
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Taiwo Esan
- Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, Illinois, 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
| | - Emily Eix
- 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
| | - Jeniel E. Nett
- 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
| | - 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
| | - Timothy Hagen
- Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, Illinois, USA
| | - Damian J. Krysan
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Department of Microbiology/Immunology, 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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10
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Andes DR, Nett JE. Analysis of Candida Antifungal Resistance Using Animal Infection Models. Methods Mol Biol 2023; 2658:225-238. [PMID: 37024706 DOI: 10.1007/978-1-0716-3155-3_16] [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] [Indexed: 04/08/2023]
Abstract
Candida frequently produces three general disease states, including mucosal candidiasis, disseminated candidiasis, and biofilm infection (which can be present with either of the other disease states). Antifungal drug resistance is intrinsic to biofilm growth and has emerged in other disease states. Mechanistic studies have uncovered the genetic pathways governing resistance to a number of antifungal agents. However, analyzing the clinical relevance of distinct mechanisms is fundamental for broadening our knowledge of antifungal drug resistance and for delineating the potential impact of targeting these pathways medically. Also, as drug-resistant strains and biofilms represent important nosocomial problems, preclinical animal models to assess the activity of novel antifungals are of great interest. Here we describe two rodent models that mimic the most common biofilm device and disseminated candidiasis states in patients. The model systems incorporate the anatomical site, immune components, and antifungal exposures relevant for the study of antifungal resistance. The models can be used to analyze mutant strains, assess the extent of drug resistance, examine biofilm formation, test new antimicrobials, and help determine drug exposures that may be linked with clinical failure.
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11
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Eix EF, Nett JE. Modeling Candida auris skin colonization: Mice, swine, and humans. PLoS Pathog 2022; 18:e1010730. [PMID: 36074786 PMCID: PMC9455849 DOI: 10.1371/journal.ppat.1010730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Emily F. Eix
- Departments of Medicine and Medical Microbiology & Immunology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Jeniel E. Nett
- Departments of Medicine and Medical Microbiology & Immunology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail:
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12
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Eix EF, Johnson CJ, Wartman KM, Kernien JF, Meudt JJ, Shanmuganayagam D, Gibson ALF, Nett JE. Ex Vivo Human and Porcine Skin Effectively Model Candida auris Colonization, Differentiating Robust and Poor Fungal Colonizers. J Infect Dis 2022; 225:1791-1795. [PMID: 35267041 PMCID: PMC9113498 DOI: 10.1093/infdis/jiac094] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [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: 02/03/2022] [Accepted: 03/08/2022] [Indexed: 11/12/2022] Open
Abstract
Candida auris proliferates and persists on the skin of patients, often leading to health care-associated infections with high mortality. Here, we describe 2 clinically relevant skin models and show that C. auris grows similarly on human and porcine skin. Additionally, we demonstrate that other Candida spp., including those with phylogenetic similarity to C. auris, do not display high growth in the skin microenvironment. These studies highlight the utility of 2 ex vivo models of C. auris colonization that allow reproducible differentiation among Candida spp., which should be a useful tool for comparison of C. auris clinical isolates and genetically mutated strains.
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Affiliation(s)
- Emily F Eix
- Department of Medicine, University of Wisconsin, Madison, Wisconsin, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, USA
| | - Chad J Johnson
- Department of Medicine, University of Wisconsin, Madison, Wisconsin, USA
| | - Kayla M Wartman
- Department of Medicine, University of Wisconsin, Madison, Wisconsin, USA
| | - John F Kernien
- Department of Medicine, University of Wisconsin, Madison, Wisconsin, USA
| | - Jennifer J Meudt
- Department of Animal and Dairy Sciences, University of Wisconsin, Madison, Wisconsin, USA
| | - Dhanansayan Shanmuganayagam
- Department of Animal and Dairy Sciences, University of Wisconsin, Madison, Wisconsin, USA
- Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
- Center for Biomedical Swine Research and Innovation, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Angela L F Gibson
- Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Jeniel E Nett
- Department of Medicine, University of Wisconsin, Madison, Wisconsin, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, USA
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Johnson CJ, Nett JE. Examining Neutrophil-Candida auris Interactions with Human Neutrophils Ex Vivo. Methods Mol Biol 2022; 2517:243-250. [PMID: 35674959 PMCID: PMC9644407 DOI: 10.1007/978-1-0716-2417-3_19] [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] [Indexed: 06/15/2023]
Abstract
Neutrophils play a key role in controlling invasive fungal infections. These phagocytes engage and kill fungal pathogens through a variety of effector mechanisms. Here, we describe how to isolate human neutrophils for ex vivo study of neutrophil-Candida auris interactions. We detail assays to measure fungal killing, phagocytosis, and reactive oxygen species production.
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Affiliation(s)
- Chad J Johnson
- Department of Medicine, University of Wisconsin, Madison, WI, USA
| | - Jeniel E Nett
- Department of Medicine, University of Wisconsin, Madison, WI, USA.
- Department of Medical Microbiology & Immunology, University of Wisconsin, Madison, WI, USA.
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14
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Abstract
Candida auris spreads person to person in hospitals and other healthcare facilities. The heightened capacity for C. auris to colonize skin contributes to the difficulty in eradicating this drug-resistant and deadly pathogen in nosocomial settings. Models for the study of C. auris skin colonization are critical for understanding this virulence trait. In light of the similarities between the skin properties of humans and pigs, pigs represent an ideal model for the investigation of skin-C. auris interactions. Here, we describe how to utilize porcine skin for ex vivo studies of C. auris colonization.
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Affiliation(s)
- Chad J Johnson
- Department of Medicine, University of Wisconsin, Madison, WI, USA
| | - J Z Alex Cheong
- Department of Medicine, University of Wisconsin, Madison, WI, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI, USA
| | - Dhanansayan Shanmuganayagam
- Department of Animal and Dairy Sciences, University of Wisconsin, Madison, WI, USA
- Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Center for Biomedical Swine Research and Innovation, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Lindsay R Kalan
- Department of Medicine, University of Wisconsin, Madison, WI, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI, USA
| | - Jeniel E Nett
- Department of Medicine, University of Wisconsin, Madison, WI, USA.
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI, USA.
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15
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Johnson CJ, Eix EF, Lam BC, Wartman KM, Meudt JJ, Shanmuganayagam D, Nett JE. Augmenting the Activity of Chlorhexidine for Decolonization of Candida auris from Porcine skin. J Fungi (Basel) 2021; 7:jof7100804. [PMID: 34682225 PMCID: PMC8537331 DOI: 10.3390/jof7100804] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 09/08/2021] [Accepted: 09/15/2021] [Indexed: 01/15/2023] Open
Abstract
Candida auris readily colonizes skin and efficiently spreads among patients in healthcare settings worldwide. Given the capacity of this drug-resistant fungal pathogen to cause invasive disease with high mortality, hospitals frequently employ chlorhexidine bathing to reduce skin colonization. Using an ex vivo skin model, we show only a mild reduction in C. auris following chlorhexidine application. This finding helps explain why chlorhexidine bathing may have failures clinically, despite potent in vitro activity. We further show that isopropanol augments the activity of chlorhexidine against C. auris on skin. Additionally, we find both tea tree (Melaleuca alternifolia) oil and lemongrass (Cymbopogon flexuosus) oil to further enhance the activity of chlorhexidine/isopropanol for decolonization. We link this antifungal activity to individual oil components and show how some of these components act synergistically with chlorhexidine/isopropanol. Together, the studies provide strategies to improve C. auris skin decolonization through the incorporation of commonly used topical compounds.
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Affiliation(s)
- Chad J. Johnson
- Department of Medicine, University of Wisconsin, Madison, WI 53706, USA; (C.J.J.); (E.F.E.); (B.C.L.); (K.M.W.)
| | - Emily F. Eix
- Department of Medicine, University of Wisconsin, Madison, WI 53706, USA; (C.J.J.); (E.F.E.); (B.C.L.); (K.M.W.)
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI 53706, USA
| | - Brandon C. Lam
- Department of Medicine, University of Wisconsin, Madison, WI 53706, USA; (C.J.J.); (E.F.E.); (B.C.L.); (K.M.W.)
| | - Kayla M. Wartman
- Department of Medicine, University of Wisconsin, Madison, WI 53706, USA; (C.J.J.); (E.F.E.); (B.C.L.); (K.M.W.)
| | - Jennifer J. Meudt
- Department of Animal and Dairy Sciences, University of Wisconsin, Madison, WI 53706, USA; (J.J.M.); (D.S.)
| | - Dhanansayan Shanmuganayagam
- Department of Animal and Dairy Sciences, University of Wisconsin, Madison, WI 53706, USA; (J.J.M.); (D.S.)
- Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI 53726, USA
- Center for Biomedical Swine Research and Innovation, University of Wisconsin School of Medicine and Public Health, Madison, WI 53726, USA
| | - Jeniel E. Nett
- Department of Medicine, University of Wisconsin, Madison, WI 53706, USA; (C.J.J.); (E.F.E.); (B.C.L.); (K.M.W.)
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI 53706, USA
- Correspondence: ; Tel.: +1-608-263-1545
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16
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Affiliation(s)
- Jeniel E Nett
- Department of Medicine, University of Wisconsin-Madison, Madison, WI, United States.,Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, United States
| | - Carolina H Pohl
- Department of Microbiology and Biochemistry, University of the Free State, Bloemfontein, South Africa
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17
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Cheong JZA, Johnson CJ, Wan H, Liu A, Kernien JF, Gibson ALF, Nett JE, Kalan LR. Priority effects dictate community structure and alter virulence of fungal-bacterial biofilms. ISME J 2021; 15:2012-2027. [PMID: 33558690 PMCID: PMC8245565 DOI: 10.1038/s41396-021-00901-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [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] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 12/21/2020] [Accepted: 01/18/2021] [Indexed: 02/06/2023]
Abstract
Polymicrobial biofilms are a hallmark of chronic wound infection. The forces governing assembly and maturation of these microbial ecosystems are largely unexplored but the consequences on host response and clinical outcome can be significant. In the context of wound healing, formation of a biofilm and a stable microbial community structure is associated with impaired tissue repair resulting in a non-healing chronic wound. These types of wounds can persist for years simmering below the threshold of classically defined clinical infection (which includes heat, pain, redness, and swelling) and cycling through phases of recurrent infection. In the most severe outcome, amputation of lower extremities may occur if spreading infection ensues. Here we take an ecological perspective to study priority effects and competitive exclusion on overall biofilm community structure in a three-membered community comprised of strains of Staphylococcus aureus, Citrobacter freundii, and Candida albicans derived from a chronic wound. We show that both priority effects and inter-bacterial competition for binding to C. albicans biofilms significantly shape community structure on both abiotic and biotic substrates, such as ex vivo human skin wounds. We further show attachment of C. freundii to C. albicans is mediated by mannose-binding lectins. Co-cultures of C. freundii and C. albicans trigger the yeast-to-hyphae transition, resulting in a significant increase in neutrophil death and inflammation compared to either species alone. Collectively, the results presented here facilitate our understanding of fungal-bacterial interactions and their effects on host-microbe interactions, pathogenesis, and ultimately, wound healing.
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Affiliation(s)
- J Z Alex Cheong
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI, USA
| | - Chad J Johnson
- Department of Medicine, Division of Infectious Disease, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI, USA
| | - Hanxiao Wan
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI, USA
| | - Aiping Liu
- Department of Surgery, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI, USA
| | - John F Kernien
- Department of Medicine, Division of Infectious Disease, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI, USA
| | - Angela L F Gibson
- Department of Surgery, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI, USA
| | - Jeniel E Nett
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI, USA
- Department of Medicine, Division of Infectious Disease, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI, USA
| | - Lindsay R Kalan
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI, USA.
- Department of Medicine, Division of Infectious Disease, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI, USA.
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18
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Kernien JF, Johnson CJ, Bayless ML, Chovanec JF, Nett JE. Neutrophils From Patients With Invasive Candidiasis Are Inhibited by Candida albicans Biofilms. Front Immunol 2020; 11:587956. [PMID: 33343568 PMCID: PMC7747767 DOI: 10.3389/fimmu.2020.587956] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 11/05/2020] [Indexed: 12/23/2022] Open
Abstract
Invasive candidiasis frequently involves medical device placement. On the surfaces of these devices, Candida can form biofilms and proliferate in adherent layers of fungal cells surrounded by a protective extracellular matrix. Due in part to this extracellular matrix, biofilms resist host defenses and antifungal drugs. Previous work (using neutrophils from healthy donors) found that one mechanism employed to resist host defenses involves the inhibition of neutrophil extracellular traps (NET) formation. NETs contain nuclear DNA, as well as antimicrobial proteins that can ensnare pathogens too large or aggregated to be effectively killed by phagocytosis. Given that these neutrophil structures are anticipated to have activity against the large aggregates of C. albicans biofilms, understanding the role of this inhibition in patients could provide insight into new treatment strategies. However, prior work has not included patients. Here, we examine NET formation by neutrophils collected from patients with invasive candidiasis. When compared to neutrophils from healthy participants, we show that patient neutrophils exhibit a heightened background level of NET release and respond to a positive stimulus by producing 100% more NETs. However, despite these physiologic differences, patient neutrophil responses to C. albicans were similar to healthy neutrophils. For both groups, planktonic cells induce strong NET release and biofilms inhibit NET formation. These results show that a mechanism of immune evasion for fungal biofilms translates to the clinical setting.
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Affiliation(s)
- John F Kernien
- Department of Medicine, University of Wisconsin-Madison, Madison, WI, United States
| | - Chad J Johnson
- Department of Medicine, University of Wisconsin-Madison, Madison, WI, United States
| | - Meg L Bayless
- Department of Medicine, University of Wisconsin-Madison, Madison, WI, United States
| | - Jack F Chovanec
- Department of Medicine, University of Wisconsin-Madison, Madison, WI, United States
| | - Jeniel E Nett
- Department of Medicine, University of Wisconsin-Madison, Madison, WI, United States.,Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, United States
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19
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Abstract
Candida spp. proliferate as surface-associated biofilms in a variety of clinical niches. These biofilms can be extremely difficult to eradicate in healthcare settings. Cells within biofilm communities grow as aggregates and produce a protective extracellular matrix, properties that impact the ability of the host to respond to infection. Cells that disperse from biofilms display a phenotype of enhanced pathogenicity. In this review, we highlight host-biofilm interactions for Candida, focusing on how biofilm formation influences innate immune responses.
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Affiliation(s)
- Emily F Eix
- Departments of Medicine and Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, United States
| | - Jeniel E Nett
- Departments of Medicine and Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, United States
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20
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Negoro PE, Xu S, Dagher Z, Hopke A, Reedy JL, Feldman MB, Khan NS, Viens AL, Alexander NJ, Atallah NJ, Scherer AK, Dutko RA, Jeffery J, Kernien JF, Fites JS, Nett JE, Klein BS, Vyas JM, Irimia D, Sykes DB, Mansour MK. Spleen Tyrosine Kinase Is a Critical Regulator of Neutrophil Responses to Candida Species. mBio 2020; 11:e02043-19. [PMID: 32398316 PMCID: PMC7218286 DOI: 10.1128/mbio.02043-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [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: 01/10/2020] [Accepted: 02/11/2020] [Indexed: 12/13/2022] Open
Abstract
Invasive fungal infections constitute a lethal threat, with patient mortality as high as 90%. The incidence of invasive fungal infections is increasing, especially in the setting of patients receiving immunomodulatory agents, chemotherapy, or immunosuppressive medications following solid-organ or bone marrow transplantation. In addition, inhibitors of spleen tyrosine kinase (Syk) have been recently developed for the treatment of patients with refractory autoimmune and hematologic indications. Neutrophils are the initial innate cellular responders to many types of pathogens, including invasive fungi. A central process governing neutrophil recognition of fungi is through lectin binding receptors, many of which rely on Syk for cellular activation. We previously demonstrated that Syk activation is essential for cellular activation, phagosomal maturation, and elimination of phagocytosed fungal pathogens in macrophages. Here, we used combined genetic and chemical inhibitor approaches to evaluate the importance of Syk in the response of neutrophils to Candida species. We took advantage of a Cas9-expressing neutrophil progenitor cell line to generate isogenic wild-type and Syk-deficient neutrophils. Syk-deficient neutrophils are unable to control the human pathogens Candida albicans, Candida glabrata, and Candida auris Neutrophil responses to Candida species, including the production of reactive oxygen species and of cytokines such as tumor necrosis factor alpha (TNF-α), the formation of neutrophil extracellular traps (NETs), phagocytosis, and neutrophil swarming, appear to be critically dependent on Syk. These results demonstrate an essential role for Syk in neutrophil responses to Candida species and raise concern for increased fungal infections with the development of Syk-modulating therapeutics.IMPORTANCE Neutrophils are recognized to represent significant immune cell mediators for the clearance and elimination of the human-pathogenic fungal pathogen Candida The sensing of fungi by innate cells is performed, in part, through lectin receptor recognition of cell wall components and downstream cellular activation by signaling components, including spleen tyrosine kinase (Syk). While the essential role of Syk in macrophages and dendritic cells is clear, there remains uncertainty with respect to its contribution in neutrophils. In this study, we demonstrated that Syk is critical for multiple cellular functions in neutrophils responding to major human-pathogenic Candida species. These data not only demonstrate the vital nature of Syk with respect to the control of fungi by neutrophils but also warn of the potential infectious complications arising from the recent clinical development of novel Syk inhibitors for hematologic and autoimmune disorders.
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Affiliation(s)
- Paige E Negoro
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Shuying Xu
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Zeina Dagher
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Alex Hopke
- Department of Surgery, Massachusetts General Hospital, Boston, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - Jennifer L Reedy
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - Michael B Feldman
- Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital, Boston Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - Nida S Khan
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - Adam L Viens
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Natalie J Alexander
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Natalie J Atallah
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Allison K Scherer
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - Richard A Dutko
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Jane Jeffery
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - John F Kernien
- Department of Medicine, University of Wisconsin-Madison, Madison Wisconsin, USA
| | - J Scott Fites
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Jeniel E Nett
- Department of Medical Microbiology and Immunology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
- Department of Medicine, University of Wisconsin-Madison, Madison Wisconsin, USA
| | - Bruce S Klein
- Department of Medical Microbiology and Immunology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
- Department of Medicine, University of Wisconsin-Madison, Madison Wisconsin, USA
| | - Jatin M Vyas
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - Daniel Irimia
- Department of Surgery, Massachusetts General Hospital, Boston, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - David B Sykes
- Center for Regenerative Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - Michael K Mansour
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
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Abstract
In healthcare settings, Candida spp. cause invasive disease with high mortality. The overwhelming majority of cases are associated with the use of critically-needed medical devices, such as vascular catheters. On the surface of these indwelling materials, Candida forms resilient, adherent biofilm communities. A hallmark characteristic of this process is the production of an extracellular matrix, which promotes fungal adhesion and provides protection from external threats. In this review, we highlight the medical relevance of device-associated Candida biofilms and draw attention to the process of Candida-biofilm-matrix production. We provide an update on the current understanding of how biofilm extracellular matrix contributes to pathogenicity, particularly through its roles in the promoting antifungal drug tolerance and immune evasion.
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Affiliation(s)
- Jeniel E. Nett
- Departments of Medicine and Medical Microbiology & Immunology, University of Wisconsin-Madison, Madison, WI 53706, USA;
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22
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Horton MV, Johnson CJ, Kernien JF, Patel TD, Lam BC, Cheong JZA, Meudt JJ, Shanmuganayagam D, Kalan LR, Nett JE. Candida auris Forms High-Burden Biofilms in Skin Niche Conditions and on Porcine Skin. mSphere 2020; 5:e00910-19. [PMID: 31969479 PMCID: PMC6977180 DOI: 10.1128/msphere.00910-19] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [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: 12/05/2019] [Accepted: 12/09/2019] [Indexed: 12/13/2022] Open
Abstract
Emerging pathogen Candida auris causes nosocomial outbreaks of life-threatening invasive candidiasis. It is unclear how this species colonizes skin and spreads in health care facilities. Here, we analyzed C. auris growth in synthetic sweat medium designed to mimic axillary skin conditions. We show that C. auris demonstrates a high capacity for biofilm formation in this milieu, well beyond that observed for the most commonly isolated Candida sp., Candida albicans The C. auris biofilms persist in environmental conditions expected in the hospital setting. To model C. auris skin colonization, we designed an ex vivo porcine skin model. We show that C. auris proliferates on porcine skin in multilayer biofilms. This capacity to thrive in skin niche conditions helps explain the propensity of C. auris to colonize skin, persist on medical devices, and rapidly spread in hospitals. These studies provide clinically relevant tools to further characterize this important growth modality.IMPORTANCE The emerging fungal pathogen Candida auris causes invasive infections and is spreading in hospitals worldwide. Why this species exhibits the capacity to transfer efficiently among patients is unknown. Our findings reveal that C. auris forms high-burden biofilms in conditions mimicking sweat on the skin surface. These adherent biofilm communities persist in environmental conditions expected in the hospital setting. Using a pig skin model, we show that C. auris also forms high-burden biofilm structures on the skin surface. Identification of this mode of growth sheds light on how this recently described pathogen persists in hospital settings and spreads among patients.
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Affiliation(s)
- Mark V Horton
- Department of Medicine, University of Wisconsin, Madison, Wisconsin, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, USA
| | - Chad J Johnson
- Department of Medicine, University of Wisconsin, Madison, Wisconsin, USA
| | - John F Kernien
- Department of Medicine, University of Wisconsin, Madison, Wisconsin, USA
| | - Tarika D Patel
- Department of Medicine, University of Wisconsin, Madison, Wisconsin, USA
| | - Brandon C Lam
- Department of Medicine, University of Wisconsin, Madison, Wisconsin, USA
| | - J Z Alex Cheong
- Department of Medicine, University of Wisconsin, Madison, Wisconsin, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, USA
| | - Jennifer J Meudt
- Department of Animal Science, University of Wisconsin, Madison, Wisconsin, USA
| | | | - Lindsay R Kalan
- Department of Medicine, University of Wisconsin, Madison, Wisconsin, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, USA
| | - Jeniel E Nett
- Department of Medicine, University of Wisconsin, Madison, Wisconsin, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, USA
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23
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Nett JE, Patel T, Johnson C, Kernien J. 2889. Skin Niche Conditions Trigger C. auris to Form Robust Biofilms That Resist Desiccation. Open Forum Infect Dis 2019. [PMCID: PMC6809095 DOI: 10.1093/ofid/ofz359.167] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Background Emerging pathogen Candida auris, the first fungus to be labeled as a public health threat, causes nosocomial outbreaks of invasive candidiasis with mortality as high as 60%. Little is known about the pathogenesis of this species that has newly arisen in the last 10 years. It is unclear why this species readily colonizes the skin and transmits efficiently in healthcare settings. We considered the possibility that C. auris may proliferate in conditions of the skin niche. Methods We analyzed the growth of C. auris (B11203) in synthetic sweat media that was designed to mimic human axillary sweat. We included C. albicans SC5314 as a comparison. To simulate sweat evaporation, we examined fungal growth in sweat media that had been concentrated up to 2.5-fold. We utilized OD600 readings to quantify planktonic and biofilm growth. Biofilm architecture was assessed by scanning electron microscopy. To determine the resilience of biofilms, biofilm viability was assessed by viable burden following desiccation. Results In the various concentrations of sweat media, C. auris formed biofilms that were 3.5- to 5-fold greater that those observed for C. albicans (A). In contrast, C. auris biofilms formed in RPMI-MOPS were approximately half the density of the C. albicans biofilms. During planktonic growth in synthetic sweat media, C. auris and C. albicans replicated similarly, including in media that had been concentrated 2.5-fold. This suggests that the various media conditions differently trigger biofilm formation for the two species. The C. auris biofilm formed in sweat media was approximately 100-fold more resistant to 1 week of desiccation (B). Conclusion Skin niche conditions trigger C. auris to form resilient biofilms that resist desiccation. We propose that this unique characteristic may account for the propensity of this species to colonize the skin and for its capacity to persist on the surface of contaminated medical devices. ![]()
Disclosures All Authors: No reported Disclosures.
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Affiliation(s)
| | - Tarika Patel
- University of Wisconsin-Madison, Madison, Wisconsin
| | - Chad Johnson
- University of Wisconsin-Madison, Madison, Wisconsin
| | - John Kernien
- University of Wisconsin-Madison, Madison, Wisconsin
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24
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Affiliation(s)
- Jeniel E. Nett
- Departments of Medicine and Medical Microbiology & Immunology, University of Wisconsin, Madison, Wisconsin, United States of America
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25
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Robinett NG, Culbertson EM, Peterson RL, Sanchez H, Andes DR, Nett JE, Culotta VC. Exploiting the vulnerable active site of a copper-only superoxide dismutase to disrupt fungal pathogenesis. J Biol Chem 2018; 294:2700-2713. [PMID: 30593499 DOI: 10.1074/jbc.ra118.007095] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [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: 12/12/2018] [Revised: 12/21/2018] [Indexed: 01/08/2023] Open
Abstract
Copper-only superoxide dismutases (SODs) represent a new class of SOD enzymes that are exclusively extracellular and unique to fungi and oomycetes. These SODs are essential for virulence of fungal pathogens in pulmonary and disseminated infections, and we show here an additional role for copper-only SODs in promoting survival of fungal biofilms. The opportunistic fungal pathogen Candida albicans expresses three copper-only SODs, and deletion of one of them, SOD5, eradicated candidal biofilms on venous catheters in a rodent model. Fungal copper-only SODs harbor an irregular active site that, unlike their Cu,Zn-SOD counterparts, contains a copper co-factor unusually open to solvent and lacks zinc for stabilizing copper binding, making fungal copper-only SODs highly vulnerable to metal chelators. We found that unlike mammalian Cu,Zn-SOD1, C. albicans SOD5 indeed rapidly loses its copper to metal chelators such as EDTA, and binding constants for Cu(II) predict that copper-only SOD5 has a much lower affinity for copper than does Cu,Zn-SOD1. We screened compounds with a variety of indications and identified several metal-binding compounds, including the ionophore pyrithione zinc (PZ), that effectively inhibit C. albicans SOD5 but not mammalian Cu,Zn-SOD1. We observed that PZ both acts as an ionophore that promotes uptake of toxic metals and inhibits copper-only SODs. The pros and cons of a vulnerable active site for copper-only SODs and the possible exploitation of this vulnerability in antifungal drug design are discussed.
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Affiliation(s)
- Natalie G Robinett
- From the Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205 and
| | - Edward M Culbertson
- From the Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205 and
| | - Ryan L Peterson
- From the Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205 and
| | - Hiram Sanchez
- the Departments of Medicine and Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin 53726
| | - David R Andes
- the Departments of Medicine and Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin 53726
| | - Jeniel E Nett
- the Departments of Medicine and Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin 53726
| | - Valeria C Culotta
- From the Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205 and
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Van Dijck P, Sjollema J, Cammue BPA, Lagrou K, Berman J, d’Enfert C, Andes DR, Arendrup MC, Brakhage AA, Calderone R, Cantón E, Coenye T, Cos P, Cowen LE, Edgerton M, Espinel-Ingroff A, Filler SG, Ghannoum M, Gow NA, Haas H, Jabra-Rizk MA, Johnson EM, Lockhart SR, Lopez-Ribot JL, Maertens J, Munro CA, Nett JE, Nobile CJ, Pfaller MA, Ramage G, Sanglard D, Sanguinetti M, Spriet I, Verweij PE, Warris A, Wauters J, Yeaman MR, Zaat SA, Thevissen K. Methodologies for in vitro and in vivo evaluation of efficacy of antifungal and antibiofilm agents and surface coatings against fungal biofilms. Microb Cell 2018; 5:300-326. [PMID: 29992128 PMCID: PMC6035839 DOI: 10.15698/mic2018.07.638] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 05/24/2018] [Indexed: 12/13/2022]
Abstract
Unlike superficial fungal infections of the skin and nails, which are the most common fungal diseases in humans, invasive fungal infections carry high morbidity and mortality, particularly those associated with biofilm formation on indwelling medical devices. Therapeutic management of these complex diseases is often complicated by the rise in resistance to the commonly used antifungal agents. Therefore, the availability of accurate susceptibility testing methods for determining antifungal resistance, as well as discovery of novel antifungal and antibiofilm agents, are key priorities in medical mycology research. To direct advancements in this field, here we present an overview of the methods currently available for determining (i) the susceptibility or resistance of fungal isolates or biofilms to antifungal or antibiofilm compounds and compound combinations; (ii) the in vivo efficacy of antifungal and antibiofilm compounds and compound combinations; and (iii) the in vitro and in vivo performance of anti-infective coatings and materials to prevent fungal biofilm-based infections.
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Affiliation(s)
- Patrick Van Dijck
- VIB-KU Leuven Center for Microbiology, Leuven, Belgium
- KU Leuven Laboratory of Molecular Cell Biology, Leuven, Belgium
| | - Jelmer Sjollema
- University of Groningen, University Medical Center Groningen, Department of BioMedical Engineering, Groningen, The Netherlands
| | - Bruno P. A. Cammue
- Centre for Microbial and Plant Genetics, KU Leuven, Leuven, Belgium
- Department of Plant Systems Biology, VIB, Ghent, Belgium
| | - Katrien Lagrou
- Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium
- Clinical Department of Laboratory Medicine and National Reference Center for Mycosis, UZ Leuven, Belgium
| | - Judith Berman
- School of Molecular Cell Biology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Israel
| | - Christophe d’Enfert
- Institut Pasteur, INRA, Unité Biologie et Pathogénicité Fongiques, Paris, France
| | - David R. Andes
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Maiken C. Arendrup
- Unit of Mycology, Statens Serum Institut, Copenhagen, Denmark
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Axel A. Brakhage
- Leibniz Institute for Natural Product Research and Infection Biology - Hans Knoell Institute (HKI), Dept. Microbiology and Molecular Biology, Friedrich Schiller University Jena, Institute of Microbiology, Jena, Germany
| | - Richard Calderone
- Department of Microbiology & Immunology, Georgetown University Medical Center, Washington DC, USA
| | - Emilia Cantón
- Severe Infection Research Group: Medical Research Institute La Fe (IISLaFe), Valencia, Spain
| | - Tom Coenye
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
- ESCMID Study Group for Biofilms, Switzerland
| | - Paul Cos
- Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Belgium
| | - Leah E. Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Mira Edgerton
- Department of Oral Biology, School of Dental Medicine, University at Buffalo, Buffalo, NY USA
| | | | - Scott G. Filler
- Division of Infectious Diseases, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Mahmoud Ghannoum
- Center for Medical Mycology, Department of Dermatology, University Hospitals Cleveland Medical Center and Case Western Re-serve University, Cleveland, OH, USA
| | - Neil A.R. Gow
- MRC Centre for Medical Mycology, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - Hubertus Haas
- Biocenter - Division of Molecular Biology, Medical University Innsbruck, Innsbruck, Austria
| | - Mary Ann Jabra-Rizk
- Department of Oncology and Diagnostic Sciences, School of Dentistry; Department of Microbiology and Immunology, School of Medicine, University of Maryland, Baltimore, USA
| | - Elizabeth M. Johnson
- National Infection Service, Public Health England, Mycology Reference Laboratory, Bristol, UK
| | | | | | - Johan Maertens
- Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium and Clinical Department of Haematology, UZ Leuven, Leuven, Belgium
| | - Carol A. Munro
- MRC Centre for Medical Mycology, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - Jeniel E. Nett
- University of Wisconsin-Madison, Departments of Medicine and Medical Microbiology & Immunology, Madison, WI, USA
| | - Clarissa J. Nobile
- Department of Molecular and Cell Biology, School of Natural Sciences, University of California, Merced, Merced, USA
| | - Michael A. Pfaller
- Departments of Pathology and Epidemiology, University of Iowa, Iowa, USA
- JMI Laboratories, North Liberty, Iowa, USA
| | - Gordon Ramage
- ESCMID Study Group for Biofilms, Switzerland
- College of Medical, Veterinary and Life Sciences, University of Glasgow, UK
| | - Dominique Sanglard
- Institute of Microbiology, University of Lausanne and University Hospital, CH-1011 Lausanne
| | - Maurizio Sanguinetti
- Institute of Microbiology, Università Cattolica del Sacro Cuore, IRCCS-Fondazione Policlinico "Agostino Gemelli", Rome, Italy
| | - Isabel Spriet
- Pharmacy Dpt, University Hospitals Leuven and Clinical Pharmacology and Pharmacotherapy, Dpt. of Pharmaceutical and Pharma-cological Sciences, KU Leuven, Belgium
| | - Paul E. Verweij
- Center of Expertise in Mycology Radboudumc/CWZ, Radboud University Medical Center, Nijmegen, the Netherlands (omit "Nijmegen" in Radboud University Medical Center)
| | - Adilia Warris
- MRC Centre for Medical Mycology, Aberdeen Fungal Group, University of Aberdeen, Foresterhill, Aberdeen, UK
| | - Joost Wauters
- KU Leuven-University of Leuven, University Hospitals Leuven, Department of General Internal Medicine, Herestraat 49, B-3000 Leuven, Belgium
| | - Michael R. Yeaman
- Geffen School of Medicine at the University of California, Los Angeles, Divisions of Molecular Medicine & Infectious Diseases, Har-bor-UCLA Medical Center, LABioMed at Harbor-UCLA Medical Center
| | - Sebastian A.J. Zaat
- Department of Medical Microbiology, Amsterdam Infection and Immunity Institute, Academic Medical Center, University of Am-sterdam, Netherlands
| | - Karin Thevissen
- Centre for Microbial and Plant Genetics, KU Leuven, Leuven, Belgium
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Fites JS, Gui M, Kernien JF, Negoro P, Dagher Z, Sykes DB, Nett JE, Mansour MK, Klein BS. An unappreciated role for neutrophil-DC hybrids in immunity to invasive fungal infections. PLoS Pathog 2018; 14:e1007073. [PMID: 29782541 PMCID: PMC5983859 DOI: 10.1371/journal.ppat.1007073] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 06/01/2018] [Accepted: 05/03/2018] [Indexed: 12/15/2022] Open
Abstract
Neutrophils are classically defined as terminally differentiated, short-lived cells; however, neutrophils can be long-lived with phenotypic plasticity. During inflammation, a subset of neutrophils transdifferentiate into a population called neutrophil-DC hybrids (PMN-DCs) having properties of both neutrophils and dendritic cells. While these cells ubiquitously appear during inflammation, the role of PMN-DCs in disease remains poorly understood. We observed the differentiation of PMN-DCs in pre-clinical murine models of fungal infection: blastomycosis, aspergillosis and candidiasis. Using reporter strains of fungal viability, we found that PMN-DCs associate with fungal cells and kill them more efficiently than undifferentiated canonical neutrophils. During pulmonary blastomycosis, PMN-DCs comprised less than 1% of leukocytes yet contributed up to 15% of the fungal killing. PMN-DCs displayed higher expression of pattern recognition receptors, greater phagocytosis, and heightened production of reactive oxygen species compared to canonical neutrophils. PMN-DCs also displayed prominent NETosis. To further study PMN-DC function, we exploited a granulocyte/macrophage progenitor (GMP) cell line, generated PMN-DCs to over 90% purity, and used them for adoptive transfer and antigen presentation studies. Adoptively transferred PMN-DCs from the GMP line enhanced protection against systemic infection in vivo. PMN-DCs pulsed with antigen activated fungal calnexin-specific transgenic T cells in vitro and in vivo, promoting the production of interferon-γ and interleukin-17 in these CD4+ T cells. Through direct fungal killing and induction of adaptive immunity, PMN-DCs are potent effectors of antifungal immunity and thereby represent innovative cell therapeutic targets in treating life-threatening fungal infections.
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Affiliation(s)
- J. Scott Fites
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States of America
| | - Michael Gui
- Department of Medical Microbiology and Immunology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States of America
| | - John F. Kernien
- Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States of America
| | - Paige Negoro
- Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Zeina Dagher
- Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - David B. Sykes
- Center for Regenerative Medicine, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jeniel E. Nett
- Department of Medical Microbiology and Immunology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States of America
- Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States of America
| | - Michael K. Mansour
- Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Bruce S. Klein
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States of America
- Department of Medical Microbiology and Immunology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States of America
- Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States of America
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28
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Abstract
Fungal infections are a continuously increasing problem in modern health care. Understanding the complex biology of the emerging pathogens and unraveling the mechanisms of host defense may form the basis for the development of more efficient diagnostic and therapeutic tools. Neutrophils play a pivotal role in the defense against fungal pathogens. These phagocytic hunters migrate towards invading fungal microorganisms and eradicate them by phagocytosis, oxidative burst and release of neutrophil extracellular traps (NETs). In the last decade, the process of NET formation has received unparalleled attention, with numerous studies revealing the relevance of this neutrophil function for control of various mycoses. Here, we describe NET formation and summarize its role as part of the innate immune defense against fungal pathogens. We highlight factors influencing the formation of these structures and molecular mechanisms employed by fungi to impair the formation of NETs or subvert their antifungal effects.
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Affiliation(s)
- Constantin F Urban
- Umeå University, Department of Clinical Microbiology, 90185 Umeå, Sweden; Umeå Centre for Microbial Research & Laboratory for Molecular Infection Medicine, Sweden.
| | - Jeniel E Nett
- University of Wisconsin-Madison, Departments of Medicine, Medical Microbiology and Immunology, 5203 Microbial Sciences Building, 1550 Linden Drive, Madison, WI 53706, USA.
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29
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Abstract
Fungal biofilms are communities of adherent cells surrounded by an extracellular matrix. These biofilms are commonly found during infection caused by a variety of fungal pathogens. Clinically, biofilm infections can be extremely difficult to eradicate due to their resistance to antifungals and host defenses. Biofilm formation can protect fungal pathogens from many aspects of the innate immune system, including killing by neutrophils and monocytes. Altered immune recognition during this phase of growth is also evident by changes in the cytokine profiles of monocytes and macrophages exposed to biofilm. In this manuscript, we review the host response to fungal biofilms, focusing on how these structures are recognized by the innate immune system. Biofilms formed by Candida, Aspergillus, and Cryptococcus have received the most attention and are highlighted. We describe common themes involved in the resilience of fungal biofilms to host immunity and give examples of biofilm defenses that are pathogen-specific.
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Affiliation(s)
- John F Kernien
- Department of Medicine, University of Wisconsin, Madison, WI, United States
| | - Brendan D Snarr
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
| | - Donald C Sheppard
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada.,Department of Medicine, McGill University, Montreal, QC, Canada
| | - Jeniel E Nett
- Department of Medicine, University of Wisconsin, Madison, WI, United States.,Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI, United States
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30
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Rossi DCP, Gleason JE, Sanchez H, Schatzman SS, Culbertson EM, Johnson CJ, McNees CA, Coelho C, Nett JE, Andes DR, Cormack BP, Culotta VC. Candida albicans FRE8 encodes a member of the NADPH oxidase family that produces a burst of ROS during fungal morphogenesis. PLoS Pathog 2017; 13:e1006763. [PMID: 29194441 PMCID: PMC5728582 DOI: 10.1371/journal.ppat.1006763] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 12/13/2017] [Accepted: 11/20/2017] [Indexed: 12/30/2022] Open
Abstract
Until recently, NADPH oxidase (NOX) enzymes were thought to be a property of multicellularity, where the reactive oxygen species (ROS) produced by NOX acts in signaling processes or in attacking invading microbes through oxidative damage. We demonstrate here that the unicellular yeast and opportunistic fungal pathogen Candida albicans is capable of a ROS burst using a member of the NOX enzyme family, which we identify as Fre8. C. albicans can exist in either a unicellular yeast-like budding form or as filamentous multicellular hyphae or pseudohyphae, and the ROS burst of Fre8 begins as cells transition to the hyphal state. Fre8 is induced during hyphal morphogenesis and specifically produces ROS at the growing tip of the polarized cell. The superoxide dismutase Sod5 is co-induced with Fre8 and our findings are consistent with a model in which extracellular Sod5 acts as partner for Fre8, converting Fre8-derived superoxide to the diffusible H2O2 molecule. Mutants of fre8Δ/Δ exhibit a morphogenesis defect in vitro and are specifically impaired in development or maintenance of elongated hyphae, a defect that is rescued by exogenous sources of H2O2. A fre8Δ/Δ deficiency in hyphal development was similarly observed in vivo during C. albicans invasion of the kidney in a mouse model for disseminated candidiasis. Moreover C. albicans fre8Δ/Δ mutants showed defects in a rat catheter model for biofilms. Together these studies demonstrate that like multicellular organisms, C. albicans expresses NOX to produce ROS and this ROS helps drive fungal morphogenesis in the animal host. We demonstrate here that the opportunistic human fungal pathogen Candida albicans uses a NADPH oxidase enzyme (NOX) and reactive oxygen species (ROS) to control morphogenesis in an animal host. C. albicans was not previously known to express NOX enzymes as these were thought to be a property of multicellular organisms, not unicellular yeasts. We describe here the identification of C. albicans Fre8 as the first NOX enzyme that can produce extracellular ROS in a unicellular yeast. C. albicans can exist as either a unicellular yeast or as multicellular elongated hyphae, and Fre8 is specially expressed during transition to the hyphal state where it works to produce ROS at the growing tip of the polarized cell. C. albicans cells lacking Fre8 exhibit a deficiency in elongated hyphae during fungal invasion of the kidney in a mouse model for systemic candidiasis. Moreover, Fre8 is required for fungal survival in a rodent model for catheter biofilms. These findings implicate a role for fungal derived ROS in controlling morphogenesis of this important fungal pathogen for public health.
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Affiliation(s)
- Diego C. P. Rossi
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Julie E. Gleason
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Hiram Sanchez
- Departments of Medicine and of Medical Microbiology and Immunology, University of Wisconsin, Madison, Madison, Wisconsin, United States of America
| | - Sabrina S. Schatzman
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Edward M. Culbertson
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Chad J. Johnson
- Departments of Medicine and of Medical Microbiology and Immunology, University of Wisconsin, Madison, Madison, Wisconsin, United States of America
| | - Christopher A. McNees
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Carolina Coelho
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Jeniel E. Nett
- Departments of Medicine and of Medical Microbiology and Immunology, University of Wisconsin, Madison, Madison, Wisconsin, United States of America
| | - David R. Andes
- Departments of Medicine and of Medical Microbiology and Immunology, University of Wisconsin, Madison, Madison, Wisconsin, United States of America
| | - Brendan P. Cormack
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Valeria C. Culotta
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
- * E-mail:
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31
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Johnson CJ, Kernien JF, Hoyer AR, Nett JE. Mechanisms involved in the triggering of neutrophil extracellular traps (NETs) by Candida glabrata during planktonic and biofilm growth. Sci Rep 2017; 7:13065. [PMID: 29026191 PMCID: PMC5638821 DOI: 10.1038/s41598-017-13588-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 09/25/2017] [Indexed: 12/14/2022] Open
Abstract
Candida spp. adhere to medical devices, such as catheters, forming drug-tolerant biofilms that resist killing by the immune system. Little is known about how C. glabrata, an emerging pathogen, resists attack by phagocytes. Here we show that upon encounter with planktonic (non-biofilm) C. glabrata, human neutrophils initially phagocytose the yeast and subsequently release neutrophil extracellular traps (NETs), complexes of DNA, histones, and proteins capable of inhibiting fungal growth and dissemination. When exposed to C. glabrata biofilms, neutrophils also release NETs, but significantly fewer than in response to planktonic cells. Impaired killing of biofilm parallels the decrease in NET production. Compared to biofilm, neutrophils generate higher levels of reactive oxygen species (ROS) when presented with planktonic organisms, and pharmacologic inhibition of NADPH-oxidase partially impairs NET production. In contrast, inhibition of phagocytosis nearly completely blocks NET release to both biofilm and planktonic organisms. Imaging of the host response to C. glabrata in a rat vascular model of infection supports a role for NET release in vivo. Taken together, these findings show that C. glabrata triggers NET release. The diminished NET response to C. glabrata biofilms likely contributes to the resilience of these structured communities to host defenses.
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Affiliation(s)
- Chad J Johnson
- Department of Medicine, University of Wisconsin, Madison, WI, United States of America
| | - John F Kernien
- Department of Medicine, University of Wisconsin, Madison, WI, United States of America
| | - Amanda R Hoyer
- Department of Medicine, University of Wisconsin, Madison, WI, United States of America
| | - Jeniel E Nett
- Department of Medicine, University of Wisconsin, Madison, WI, United States of America. .,Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI, United States of America.
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32
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Bawadekar M, Shim D, Johnson CJ, Warner TF, Rebernick R, Damgaard D, Nielsen CH, Pruijn GJM, Nett JE, Shelef MA. Peptidylarginine deiminase 2 is required for tumor necrosis factor alpha-induced citrullination and arthritis, but not neutrophil extracellular trap formation. J Autoimmun 2017; 80:39-47. [PMID: 28188029 DOI: 10.1016/j.jaut.2017.01.006] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [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: 11/21/2016] [Revised: 01/23/2017] [Accepted: 01/31/2017] [Indexed: 10/20/2022]
Abstract
Citrullination, the post-translational conversion of arginines to citrullines, may contribute to rheumatoid arthritis development given the generation of anti-citrullinated protein antibodies (ACPAs). However, it is not known which peptidylarginine deiminase (PAD) catalyzes the citrullination seen in inflammation. PAD4 exacerbates inflammatory arthritis and is critical for neutrophil extracellular traps (NETs). NETs display citrullinated antigens targeted by ACPAs and thus may be a source of citrullinated protein. However, PAD4 is not required for citrullination in inflamed lungs. PAD2 is important for citrullination in healthy tissues and is present in NETs, but its role in citrullination in the inflamed joint, NETosis and inflammatory arthritis is unknown. Here we use mice with TNFα-induced inflammatory arthritis, a model of rheumatoid arthritis, to identify the roles of PAD2 and PAD4 in citrullination, NETosis, and arthritis. In mice with TNFα-induced arthritis, citrullination in the inflamed ankle was increased as determined by western blot. This increase was unchanged in the ankles of mice that lack PAD4. In contrast, citrullination was nearly absent in the ankles of PAD2-deficient mice. Interestingly, PAD2 was not required for NET formation as assessed by immunofluorescence or for killing of Candida albicans as determined by viability assay. Finally, plasma cell numbers as assessed by flow cytometry, IgG levels quantified by ELISA, and inflammatory arthritis as determined by clinical and pathological scoring were all reduced in the absence of PAD2. Thus, PAD2 contributes to TNFα-induced citrullination and arthritis, but is not required for NETosis. In contrast, PAD4, which is critical for NETosis, is dispensable for generalized citrullination supporting the possibility that NETs may not be a major source of citrullinated protein in arthritis.
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Affiliation(s)
- Mandar Bawadekar
- Department of Medicine, University of Wisconsin, Madison, WI, USA
| | - Daeun Shim
- Department of Medicine, University of Wisconsin, Madison, WI, USA
| | - Chad J Johnson
- Department of Medicine, University of Wisconsin, Madison, WI, USA
| | - Thomas F Warner
- Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison, WI, USA
| | - Ryan Rebernick
- Department of Medicine, University of Wisconsin, Madison, WI, USA
| | - Dres Damgaard
- Institute for Inflammation Research, Center for Rheumatology and Spine Diseases, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Claus H Nielsen
- Institute for Inflammation Research, Center for Rheumatology and Spine Diseases, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Ger J M Pruijn
- Institute for Molecules and Materials and Radboud Institute for Molecular Life Sciences, Radboud University, Nijmegen, The Netherlands
| | - Jeniel E Nett
- Department of Medicine, University of Wisconsin, Madison, WI, USA; Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, USA
| | - Miriam A Shelef
- Department of Medicine, University of Wisconsin, Madison, WI, USA; William S. Middleton Memorial Veterans Hospital, Madison, WI, USA.
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33
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Abstract
Candida spp. are among the most common nosocomial fungal pathogens and are notorious for their propensity toward biofilm formation. When growing on a medical device or mucosal surface, these organisms reside as communities embedded in a protective matrix, resisting host defenses. The host responds to Candida biofilm by depositing a variety of proteins that become incorporated into the biofilm matrix. Compared to free-floating Candida, leukocytes are less effective against Candida within a biofilm. This review highlights recent advances describing the host's response to Candida biofilms using ex vivo and in vivo models of mucosal and device-associated biofilm infections.
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Affiliation(s)
- Jeniel E Nett
- University of Wisconsin-Madison, Departments of Medicine, Medical Microbiology and Immunology, 5203 Microbial Sciences Building, 1550 Linden Drive, Madison, WI 53706, USA.
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34
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Fox EP, Bui CK, Nett JE, Hartooni N, Mui MC, Andes DR, Nobile CJ, Johnson AD. An expanded regulatory network temporally controls Candida albicans biofilm formation. Mol Microbiol 2015; 96:1226-39. [PMID: 25784162 PMCID: PMC4464956 DOI: 10.1111/mmi.13002] [Citation(s) in RCA: 118] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/15/2015] [Indexed: 01/10/2023]
Abstract
Candida albicans biofilms are composed of highly adherent and densely arranged cells with properties distinct from those of free‐floating (planktonic) cells. These biofilms are a significant medical problem because they commonly form on implanted medical devices, are drug resistant and are difficult to remove. C. albicans biofilms are not static structures; rather they are dynamic and develop over time. Here we characterize gene expression in biofilms during their development, and by comparing them to multiple planktonic reference states, we identify patterns of gene expression relevant to biofilm formation. In particular, we document time‐dependent changes in genes involved in adhesion and metabolism, both of which are at the core of biofilm development. Additionally, we identify three new regulators of biofilm formation, Flo8, Gal4, and Rfx2, which play distinct roles during biofilm development over time. Flo8 is required for biofilm formation at all time points, and Gal4 and Rfx2 are needed for proper biofilm formation at intermediate time points.
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Affiliation(s)
- Emily P Fox
- Department of Microbiology and Immunology, University of California, San Francisco, CA, USA.,Tetrad Program, Department of Biochemistry and Biophysics, University of California, San Francisco, CA, USA
| | - Catherine K Bui
- School of Natural Sciences, University of California, Merced, CA, USA
| | - Jeniel E Nett
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI, USA.,Department of Medicine, University of Wisconsin, Madison, WI, USA
| | - Nairi Hartooni
- Department of Microbiology and Immunology, University of California, San Francisco, CA, USA
| | - Michael C Mui
- Department of Microbiology and Immunology, University of California, San Francisco, CA, USA
| | - David R Andes
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI, USA.,Department of Medicine, University of Wisconsin, Madison, WI, USA
| | - Clarissa J Nobile
- School of Natural Sciences, University of California, Merced, CA, USA
| | - Alexander D Johnson
- Department of Microbiology and Immunology, University of California, San Francisco, CA, USA
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Zarnowski R, Westler WM, Lacmbouh GA, Marita JM, Bothe JR, Bernhardt J, Lounes-Hadj Sahraoui A, Fontaine J, Sanchez H, Hatfield RD, Ntambi JM, Nett JE, Mitchell AP, Andes DR. Novel entries in a fungal biofilm matrix encyclopedia. mBio 2014; 5:e01333-14. [PMID: 25096878 PMCID: PMC4128356 DOI: 10.1128/mbio.01333-14] [Citation(s) in RCA: 203] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 07/10/2014] [Indexed: 12/31/2022] Open
Abstract
Virulence of Candida is linked with its ability to form biofilms. Once established, biofilm infections are nearly impossible to eradicate. Biofilm cells live immersed in a self-produced matrix, a blend of extracellular biopolymers, many of which are uncharacterized. In this study, we provide a comprehensive analysis of the matrix manufactured by Candida albicans both in vitro and in a clinical niche animal model. We further explore the function of matrix components, including the impact on drug resistance. We uncovered components from each of the macromolecular classes (55% protein, 25% carbohydrate, 15% lipid, and 5% nucleic acid) in the C. albicans biofilm matrix. Three individual polysaccharides were identified and were suggested to interact physically. Surprisingly, a previously identified polysaccharide of functional importance, β-1,3-glucan, comprised only a small portion of the total matrix carbohydrate. Newly described, more abundant polysaccharides included α-1,2 branched α-1,6-mannans (87%) associated with unbranched β-1,6-glucans (13%) in an apparent mannan-glucan complex (MGCx). Functional matrix proteomic analysis revealed 458 distinct activities. The matrix lipids consisted of neutral glycerolipids (89.1%), polar glycerolipids (10.4%), and sphingolipids (0.5%). Examination of matrix nucleic acid identified DNA, primarily noncoding sequences. Several of the in vitro matrix components, including proteins and each of the polysaccharides, were also present in the matrix of a clinically relevant in vivo biofilm. Nuclear magnetic resonance (NMR) analysis demonstrated interaction of aggregate matrix with the antifungal fluconazole, consistent with a role in drug impedance and contribution of multiple matrix components. Importance: This report is the first to decipher the complex and unique macromolecular composition of the Candida biofilm matrix, demonstrate the clinical relevance of matrix components, and show that multiple matrix components are needed for protection from antifungal drugs. The availability of these biochemical analyses provides a unique resource for further functional investigation of the biofilm matrix, a defining trait of this lifestyle.
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Affiliation(s)
- Robert Zarnowski
- Department of Medicine, Infectious Diseases, University of Wisconsin, Madison, Wisconsin, USA
| | - William M Westler
- National Magnetic Resonance Facility at Madison, University of Wisconsin, Madison, Wisconsin, USA
| | | | - Jane M Marita
- Dairy Forage Research Center, U.S. Department of Agriculture, Madison, Wisconsin, USA
| | - Jameson R Bothe
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin, USA
| | | | - Anissa Lounes-Hadj Sahraoui
- Université du Littoral Côte d'Opale, Unité de Chimie Environnementale at Interactions sur le Vivant, Calais, France
| | - Joël Fontaine
- Université du Littoral Côte d'Opale, Unité de Chimie Environnementale at Interactions sur le Vivant, Calais, France
| | - Hiram Sanchez
- Department of Medicine, Infectious Diseases, University of Wisconsin, Madison, Wisconsin, USA
| | - Ronald D Hatfield
- Dairy Forage Research Center, U.S. Department of Agriculture, Madison, Wisconsin, USA
| | | | | | - Aaron P Mitchell
- Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
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36
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Abstract
While proliferating in its most common mode of growth, a biofilm, Candida spp. exhibit increased resistance to available antifungal agents. These adherent communities are difficult to eradicate and often responsible for treatment failures. New therapies are urgently needed to treat a variety of Candida biofilm infections in the medical setting. This review discusses the medical relevance of Candida biofilms, the drug resistance associated with this mode of growth, and approaches to combat these resilient infections.
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Affiliation(s)
- Jeniel E Nett
- Department of Medicine, Department of Medical Microbiology and Immunology, University of Wisconsin, 4153 Microbial Sciences Building, 1550 Linden Drive, Madison, WI 53705, USA
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37
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Taff HT, Nett JE, Zarnowski R, Ross KM, Sanchez H, Cain MT, Hamaker J, Mitchell AP, Andes DR. A Candida biofilm-induced pathway for matrix glucan delivery: implications for drug resistance. PLoS Pathog 2012; 8:e1002848. [PMID: 22876186 PMCID: PMC3410897 DOI: 10.1371/journal.ppat.1002848] [Citation(s) in RCA: 204] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Accepted: 06/22/2012] [Indexed: 01/10/2023] Open
Abstract
Extracellular polysaccharides are key constituents of the biofilm matrix of many microorganisms. One critical carbohydrate component of Candida albicans biofilms, β-1,3 glucan, has been linked to biofilm protection from antifungal agents. In this study, we identify three glucan modification enzymes that function to deliver glucan from the cell to the extracellular matrix. These enzymes include two predicted glucan transferases and an exo-glucanase, encoded by BGL2, PHR1, and XOG1, respectively. We show that the enzymes are crucial for both delivery of β-1,3 glucan to the biofilm matrix and for accumulation of mature matrix biomass. The enzymes do not appear to impact cell wall glucan content of biofilm cells, nor are they necessary for filamentation or biofilm formation. We demonstrate that mutants lacking these genes exhibit enhanced susceptibility to the commonly used antifungal, fluconazole, during biofilm growth only. Transcriptional analysis and biofilm phenotypes of strains with multiple mutations suggest that these enzymes act in a complementary fashion to distribute matrix downstream of the primary β-1,3 glucan synthase encoded by FKS1. Furthermore, our observations suggest that this matrix delivery pathway works independently from the C. albicans ZAP1 matrix formation regulatory pathway. These glucan modification enzymes appear to play a biofilm-specific role in mediating the delivery and organization of mature biofilm matrix. We propose that the discovery of inhibitors for these enzymes would provide promising anti-biofilm therapeutics.
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Affiliation(s)
- Heather T. Taff
- Departments of Medicine and Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin
| | - Jeniel E. Nett
- Departments of Medicine and Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin
| | - Robert Zarnowski
- Departments of Medicine and Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin
| | - Kelly M. Ross
- Departments of Medicine and Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin
| | - Hiram Sanchez
- Departments of Medicine and Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin
| | - Mike T. Cain
- Departments of Medicine and Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin
| | - Jessica Hamaker
- Department of Microbiology, Columbia University, New York, New York
| | - Aaron P. Mitchell
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - David R. Andes
- Departments of Medicine and Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin
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38
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Finkel JS, Xu W, Huang D, Hill EM, Desai JV, Woolford CA, Nett JE, Taff H, Norice CT, Andes DR, Lanni F, Mitchell AP. Portrait of Candida albicans adherence regulators. PLoS Pathog 2012; 8:e1002525. [PMID: 22359502 PMCID: PMC3280983 DOI: 10.1371/journal.ppat.1002525] [Citation(s) in RCA: 167] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Accepted: 12/21/2011] [Indexed: 12/20/2022] Open
Abstract
Cell-substrate adherence is a fundamental property of microorganisms that enables them to exist in biofilms. Our study focuses on adherence of the fungal pathogen Candida albicans to one substrate, silicone, that is relevant to device-associated infection. We conducted a mutant screen with a quantitative flow-cell assay to identify thirty transcription factors that are required for adherence. We then combined nanoString gene expression profiling with functional analysis to elucidate relationships among these transcription factors, with two major goals: to extend our understanding of transcription factors previously known to govern adherence or biofilm formation, and to gain insight into the many transcription factors we identified that were relatively uncharacterized, particularly in the context of adherence or cell surface biogenesis. With regard to the first goal, we have discovered a role for biofilm regulator Bcr1 in adherence, and found that biofilm regulator Ace2 is a major functional target of chromatin remodeling factor Snf5. In addition, Bcr1 and Ace2 share several target genes, pointing to a new connection between them. With regard to the second goal, our findings reveal existence of a large regulatory network that connects eleven adherence regulators, the zinc-response regulator Zap1, and approximately one quarter of the predicted cell surface protein genes in this organism. This limited yet sensitive glimpse of mutant gene expression changes had thus defined one of the broadest cell surface regulatory networks in C. albicans.
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Affiliation(s)
- Jonathan S. Finkel
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Wenjie Xu
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - David Huang
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Elizabeth M. Hill
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Jigar V. Desai
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Carol A. Woolford
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Jeniel E. Nett
- Department of Medicine, Section of Infectious Diseases, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Heather Taff
- Department of Medicine, Section of Infectious Diseases, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Carmelle T. Norice
- Department of Microbiology, Columbia University, New York, New York, United States of America
| | - David R. Andes
- Department of Medicine, Section of Infectious Diseases, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Frederick Lanni
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Aaron P. Mitchell
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
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39
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Abstract
Candida grows on devices producing treatment resistant biofilms. A key tool for the study of biofilms includes an accurate assessment of viable cell growth. This study systematically tested seven techniques, among which the XTT assay provided the most reproducible, accurate, and efficient method for the quantitative estimation of C. albicans biofilms.
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Affiliation(s)
| | - Jeniel E. Nett
- Department of Microbiology and Immunology, Wisconsin, USA
- Department of William S. Middleton Veterans Hospital, Wisconsin, USA
| | - David R. Andes
- Department of Microbiology and Immunology, Wisconsin, USA
- Department of Medicine, University of Wisconsin, Wisconsin, USA
- Department of William S. Middleton Veterans Hospital, Wisconsin, USA
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40
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Nobile CJ, Fox EP, Nett JE, Sorrells TR, Mitrovich QM, Hernday AD, Tuch BB, Andes DR, Johnson AD. A recently evolved transcriptional network controls biofilm development in Candida albicans. Cell 2012; 148:126-38. [PMID: 22265407 PMCID: PMC3266547 DOI: 10.1016/j.cell.2011.10.048] [Citation(s) in RCA: 504] [Impact Index Per Article: 42.0] [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: 05/03/2011] [Revised: 08/09/2011] [Accepted: 10/18/2011] [Indexed: 10/14/2022]
Abstract
A biofilm is an organized, resilient group of microbes in which individual cells acquire properties, such as drug resistance, that are distinct from those observed in suspension cultures. Here, we describe and analyze the transcriptional network controlling biofilm formation in the pathogenic yeast Candida albicans, whose biofilms are a major source of medical device-associated infections. We have combined genetic screens, genome-wide approaches, and two in vivo animal models to describe a master circuit controlling biofilm formation, composed of six transcription regulators that form a tightly woven network with ∼1,000 target genes. Evolutionary analysis indicates that the biofilm network has rapidly evolved: genes in the biofilm circuit are significantly weighted toward genes that arose relatively recently with ancient genes being underrepresented. This circuit provides a framework for understanding many aspects of biofilm formation by C. albicans in a mammalian host. It also provides insights into how complex cell behaviors can arise from the evolution of transcription circuits.
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Affiliation(s)
- Clarissa J Nobile
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94102, USA.
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41
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Abstract
Candida frequently grows as a biofilm, or an adherent community of cells protected from both the host immune system and antimicrobial therapies. Biofilms represent the predominant mode of growth for many clinical infections, including those associated with placement of a medical device. Here, we describe a model for Candida biofilm infection of one important clinical niche, a venous catheter. This animal model system incorporates the anatomical site, immune components, and fluid dynamics of a patient venous catheter infection and can be used for study of biofilm formation, drug resistance, and gene expression.
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Affiliation(s)
- Jeniel E. Nett
- University of Wisconsin, MFCB 1685 Highland Ave, Madison, WI 53705, Phone: 608-263-1545
| | - Karen Marchillo
- University of Wisconsin, MFCB 1685 Highland Ave, Madison, WI 53705, Phone: 608-263-1545
| | - David R. Andes
- University of Wisconsin, MFCB 1685 Highland Ave, Madison, WI 53705, Phone: 608-263-1545
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42
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Nett JE, Sanchez H, Cain MT, Ross KM, Andes DR. Interface of Candida albicans biofilm matrix-associated drug resistance and cell wall integrity regulation. Eukaryot Cell 2011; 10:1660-9. [PMID: 21666076 PMCID: PMC3232725 DOI: 10.1128/ec.05126-11] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Accepted: 06/01/2011] [Indexed: 01/12/2023]
Abstract
Candida albicans frequently infects medical devices by growing as a biofilm, i.e., a community of adherent organisms entrenched in an extracellular matrix. During biofilm growth, Candida spp. acquire the ability to resist high concentrations of antifungal drugs. One recently recognized biofilm resistance mechanism involves drug sequestration by matrix β-1,3 glucan. Using a candidate gene approach, we investigated potential C. albicans β-1,3-glucan regulators, based on their homology to Saccharomyces cerevisiae, including SMI1 and protein kinase C (PKC) pathway components. We identified a role for the SMI1 in biofilm matrix glucan production and development of the associated drug resistance phenotype. This pathway appears to act through transcription factor Rlmp and glucan synthase Fks1p. The phenotypes of these mutant biofilms mimicked those of the smi1Δ/smi1Δ biofilm, and overexpression of FKS1 in the smi1Δ/smi1Δ mutant restored the biofilm resistant phenotype. However, control of this pathway is distinct from that of the upstream PKC pathway because the pkc1Δ/pkc1Δ, bck1Δ/bck1Δ, mkk2Δ/mkk2Δ, and mkc1Δ/mkc1Δ biofilms retained the resistant phenotype of the parent strain. In addition, resistance to cell-perturbing agents and gene expression data do not support a significant role for the cell wall integrity pathway during the biofilm formation. Here we show that Smi1p functions in conjunction with Rlm1p and Fks1p to produce drug-sequestering biofilm β-glucan. Our work provides new insight into how the C. albicans biofilm matrix production and drug resistance pathways intersect with the planktonic cell wall integrity pathway. This novel connection helps explain how pathogens in a multicellular biofilm community are protected from anti-infective therapy.
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Affiliation(s)
- Jeniel E. Nett
- Department of Medicine
- William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin
| | | | | | | | - David R. Andes
- Department of Medicine
- Department of Medical Microbiology and Immunology, University of Wisconsin
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43
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Finkel JS, Yudanin N, Nett JE, Andes DR, Mitchell AP. Application of the systematic "DAmP" approach to create a partially defective C. albicans mutant. Fungal Genet Biol 2011; 48:1056-61. [PMID: 21820070 PMCID: PMC3185220 DOI: 10.1016/j.fgb.2011.07.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [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: 05/11/2011] [Revised: 07/19/2011] [Accepted: 07/20/2011] [Indexed: 11/18/2022]
Abstract
An understanding of gene function often relies upon creating multiple kinds of alleles. Functional analysis in Candida albicans, a major fungal pathogen, has generally included characterization of mutant strains with insertion or deletion alleles and over-expression alleles. Here we use in C. albicans another type of allele that has been employed effectively in the model yeast Saccharomyces cerevisiae, a "Decreased Abundance by mRNA Perturbation" (DAmP) allele (Yan et al., 2008). DAmP alleles are created systematically through replacement of 30 noncoding regions with nonfunctional heterologous sequences, and thus are broadly applicable. We used a DAmP allele to probe the function of Sun41, a surface protein with roles in cell wall integrity, cell-cell adherence, hyphal formation, and biofilm formation that has been suggested as a possible therapeutic target (Firon et al., 2007; Hiller et al., 2007; Norice et al., 2007). A SUN41-DAmP allele results in approximately 10-fold reduced levels of SUN41 RNA, and yields intermediate phenotypes in most assays. We report that a sun41Δ/Δ mutant is defective in biofilm formation in vivo, and that the SUN41-DAmP allele complements that defect. This finding argues that Sun41 may not be an ideal therapeutic target for biofilm inhibition, since a 90% decrease in activity has little effect on biofilm formation in vivo. We anticipate that DAmP alleles of C. albicans genes will be informative for analysis of other prospective drug targets, including essential genes.
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Affiliation(s)
- JS Finkel
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - N Yudanin
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - JE Nett
- Department of Medicine, Section of Infectious Diseases, University of Wisconsin, Madison, Wisconsin 53792 USA
| | - DR Andes
- Department of Medicine, Section of Infectious Diseases, University of Wisconsin, Madison, Wisconsin 53792 USA
| | - AP Mitchell
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
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44
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Chen YL, Brand A, Morrison EL, Silao FGS, Bigol UG, Malbas FF, Nett JE, Andes DR, Solis NV, Filler SG, Averette A, Heitman J. Calcineurin controls drug tolerance, hyphal growth, and virulence in Candida dubliniensis. Eukaryot Cell 2011; 10:803-19. [PMID: 21531874 PMCID: PMC3127677 DOI: 10.1128/ec.00310-10] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Accepted: 04/11/2011] [Indexed: 01/09/2023]
Abstract
Candida dubliniensis is an emerging pathogenic yeast species closely related to Candida albicans and frequently found colonizing or infecting the oral cavities of HIV/AIDS patients. Drug resistance during C. dubliniensis infection is common and constitutes a significant therapeutic challenge. The calcineurin inhibitor FK506 exhibits synergistic fungicidal activity with azoles or echinocandins in the fungal pathogens C. albicans, Cryptococcus neoformans, and Aspergillus fumigatus. In this study, we show that calcineurin is required for cell wall integrity and wild-type tolerance of C. dubliniensis to azoles and echinocandins; hence, these drugs are candidates for combination therapy with calcineurin inhibitors. In contrast to C. albicans, in which the roles of calcineurin and Crz1 in hyphal growth are unclear, here we show that calcineurin and Crz1 play a clearly demonstrable role in hyphal growth in response to nutrient limitation in C. dubliniensis. We further demonstrate that thigmotropism is controlled by Crz1, but not calcineurin, in C. dubliniensis. Similar to C. albicans, C. dubliniensis calcineurin enhances survival in serum. C. dubliniensis calcineurin and crz1/crz1 mutants exhibit attenuated virulence in a murine systemic infection model, likely attributable to defects in cell wall integrity, hyphal growth, and serum survival. Furthermore, we show that C. dubliniensis calcineurin mutants are unable to establish murine ocular infection or form biofilms in a rat denture model. That calcineurin is required for drug tolerance and virulence makes fungus-specific calcineurin inhibitors attractive candidates for combination therapy with azoles or echinocandins against emerging C. dubliniensis infections.
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Affiliation(s)
- Ying-Lien Chen
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina
| | - Alexandra Brand
- Aberdeen Fungal Group, School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Emma L. Morrison
- Aberdeen Fungal Group, School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Fitz Gerald S. Silao
- Department of Microbiology and Parasitology, University of Perpetual Help-Dr. Jose G. Tamayo Medical University, Biñan, Laguna, Philippines
| | - Ursela G. Bigol
- Environment and Biotechnology Division, Department of Science and Technology, Bicutan, Philippines
| | | | - Jeniel E. Nett
- Departments of Medicine
- Medical Microbiology and Immunology, University of Wisconsin
- William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin
| | - David R. Andes
- Departments of Medicine
- Medical Microbiology and Immunology, University of Wisconsin
- William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin
| | - Norma V. Solis
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, California
| | - Scott G. Filler
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, California
- David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Anna Averette
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina
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45
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Nett JE, Cain MT, Crawford K, Andes DR. Optimizing a Candida biofilm microtiter plate model for measurement of antifungal susceptibility by tetrazolium salt assay. J Clin Microbiol 2011; 49:1426-33. [PMID: 21227984 PMCID: PMC3122839 DOI: 10.1128/jcm.02273-10] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [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: 11/10/2010] [Accepted: 01/06/2011] [Indexed: 11/20/2022] Open
Abstract
Candida spp. infect medical devices, such as venous and urinary catheters, by adhering to the surface and forming a community of drug-resistant cells surrounded by a matrix. The ability to measure drug activity during this biofilm mode of growth is of interest for the investigation of resistance mechanisms and novel antifungal therapies. The tetrazolium salt (XTT) reduction assay is the test most commonly used to estimate viable biofilm growth and to examine the impact of biofilm therapies. The primary goal of the current experiments was to identify assay variables that affect the XTT assay result in order to improve assay reproducibility, sensitivity, and throughput for the study of antifungal activity. The species used in the current studies included Candida albicans, C. parapsilosis, and C. glabrata. The assay variables that were studied included the impact of culture conditions, the duration of biofilm growth, the timing and frequency of drug administration, the XTT source and concentration, and the duration of XTT incubation. The conditions that impacted the assay readout and altered assay sensitivity included the duration of biofilm growth, the frequency of drug dosing, and the duration of XTT incubation. Several factors were found to reduce time and assay expense, including the elimination of washing steps, the shortening of incubation times, and the use of lower XTT concentrations. A description of assay pitfalls and troubleshooting is included. Recognition of these technical variables should allow investigators to better design reproducible biofilm therapeutic studies.
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Affiliation(s)
- Jeniel E. Nett
- Departments of Microbiology and Immunology
- William S. Middleton Veterans Hospital, Madison, Wisconsin
| | | | | | - David R. Andes
- Departments of Microbiology and Immunology
- Medicine, University of Wisconsin
- William S. Middleton Veterans Hospital, Madison, Wisconsin
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46
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Nett JE, Marchillo K, Spiegel CA, Andes DR. Development and validation of an in vivo Candida albicans biofilm denture model. Infect Immun 2010; 78:3650-9. [PMID: 20605982 PMCID: PMC2937450 DOI: 10.1128/iai.00480-10] [Citation(s) in RCA: 119] [Impact Index Per Article: 8.5] [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: 05/07/2010] [Revised: 06/16/2010] [Accepted: 06/25/2010] [Indexed: 11/20/2022] Open
Abstract
The most common form of oral candidiasis, denture-associated stomatitis, involves biofilm growth on an oral prosthetic surface. Cells in this unique environment are equipped to withstand host defenses and survive antifungal therapy. Studies of the biofilm process on dentures have primarily been limited to in vitro models. We developed a rodent acrylic denture model and characterized the Candida albicans and mixed oral bacterial flora biofilm formation, architecture, and drug resistance in vivo, using time course quantitative culture experiments, confocal microscopy, scanning electron microscopy, and antifungal susceptibility assays. We also examined the utility of the model for measurement of C. albicans gene expression and tested the impact of a specific gene product (Bcr1p) on biofilm formation. Finally, we assessed the mucosal host response to the denture biofilm and found the mucosal histopathology to be consistent with that of acute human denture stomatitis, demonstrating fungal invasion and neutrophil infiltration. This current oral denture model mimics human denture stomatitis and should be useful for testing the impact of gene disruption on biofilm formation, studying the impact of anti-infectives, examining the biology of mixed Candida-oral bacterial flora biofilm infections, and characterizing the host immunologic response to this disease process.
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Affiliation(s)
- Jeniel E. Nett
- Departments of Medicine, Medical Microbiology and Immunology, Pathology and Laboratory Medicine, University of Wisconsin, Madison, Wisconsin
| | - Karen Marchillo
- Departments of Medicine, Medical Microbiology and Immunology, Pathology and Laboratory Medicine, University of Wisconsin, Madison, Wisconsin
| | - Carol A. Spiegel
- Departments of Medicine, Medical Microbiology and Immunology, Pathology and Laboratory Medicine, University of Wisconsin, Madison, Wisconsin
| | - David R. Andes
- Departments of Medicine, Medical Microbiology and Immunology, Pathology and Laboratory Medicine, University of Wisconsin, Madison, Wisconsin
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Nett JE, Crawford K, Marchillo K, Andes DR. Role of Fks1p and matrix glucan in Candida albicans biofilm resistance to an echinocandin, pyrimidine, and polyene. Antimicrob Agents Chemother 2010; 54:3505-8. [PMID: 20516280 PMCID: PMC2916329 DOI: 10.1128/aac.00227-10] [Citation(s) in RCA: 153] [Impact Index Per Article: 10.9] [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: 02/16/2010] [Revised: 04/22/2010] [Accepted: 05/24/2010] [Indexed: 11/20/2022] Open
Abstract
Candida infections frequently involve drug-resistant biofilm growth on device surfaces. Glucan synthase gene FKS1 has been linked to triazole resistance in Candida biofilms. We tested the impact of FKS1 modulation on susceptibility to additional antifungal classes. Reduction of FKS1 expression rendered biofilms more susceptible to amphotericin B, anidulafungin, and flucytosine. Increased resistance to anidulafungin and amphotericin B was observed for biofilms overexpressing FKS1. These findings suggest that Candida biofilm glucan sequestration is a multidrug resistance mechanism.
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Affiliation(s)
- Jeniel E. Nett
- Departments of Medicine, Medical Microbiology and Immunology, Cellular and Molecular Biology, University of Wisconsin, Madison, Wisconsin
| | - Kyler Crawford
- Departments of Medicine, Medical Microbiology and Immunology, Cellular and Molecular Biology, University of Wisconsin, Madison, Wisconsin
| | - Karen Marchillo
- Departments of Medicine, Medical Microbiology and Immunology, Cellular and Molecular Biology, University of Wisconsin, Madison, Wisconsin
| | - David R. Andes
- Departments of Medicine, Medical Microbiology and Immunology, Cellular and Molecular Biology, University of Wisconsin, Madison, Wisconsin
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Abstract
Medical devices provide an ecological niche for microbes to flourish as a biofilm community, protected from antimicrobials and host defenses. Biofilms formed by Candida albicans, the most common fungal pathogen, survive exposure to extraordinarily high drug concentrations. Here, we show that beta-glucan synthase Fks1p produces glucan, which is deposited in the biofilm matrix. The extracellular glucan is required for biofilm resistance and acts by sequestering antifungals, rendering cells resistant to their action. These findings provide the genetic basis for how biofilm matrix production governs drug resistance by impeding drug diffusion and also identify a useful biofilm drug target.
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Affiliation(s)
- Jeniel E. Nett
- Dept of Medicine, University of Wisconsin, 600 Highland Ave, Room H4.572, Madison, WI 53792
- Cellular and Molecular Biology, University of Wisconsin, 600 Highland Ave, Room H4.572, Madison, WI 53792
| | - Hiram Sanchez
- Dept of Medicine, University of Wisconsin, 600 Highland Ave, Room H4.572, Madison, WI 53792
| | - Michael T Cain
- Dept of Medicine, University of Wisconsin, 600 Highland Ave, Room H4.572, Madison, WI 53792
| | - David R. Andes
- Dept of Medicine, University of Wisconsin, 600 Highland Ave, Room H4.572, Madison, WI 53792
- Medical Microbiology and Immunology, University of Wisconsin, 600 Highland Ave, Room H4.572, Madison, WI 53792
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Abstract
Candida infection of devices is common and invariably associated with biofilm growth. Exploratory microarray studies were undertaken to identify target genes associated with biofilm formation from an in vivo catheter model over time. We compared messenger RNA levels from Candida albicans grown in an in vivo central venous catheter biofilm model at 12 h (intermediate growth) and 24 h (mature) to in vitro planktonic cells without a biofilm substrate, using C. albicans oligo arrays. A total of 124 transcripts were similarly up-regulated at the 12- and 24-h time points. Ontology categories most highly represented included energy/metabolism (12%), carbohydrate (10%), and protein (13%) synthesis and modification, and transport (6%). Numerous genes were previously identified from in vitro biofilm studies. These genes included those associated with hyphal growth, amino acid metabolism, adherence, drug resistance, ergosterol biosynthesis, and beta-glucan synthesis. In the current data set, adherence genes were unique to those from the earlier time point. Differences between the current in vivo biofilm expression data and that previously reported from in vitro models, including alterations in metabolism and carbohydrate processing, may be due to the continuous availability of nutrients from host serum and the incorporation of the host-pathogen interaction.
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Affiliation(s)
- Jeniel E. Nett
- Dept of Medicine, University of Wisconsin
- Dept of Cellular and Molecular Biology, University of Wisconsin
| | | | | | - David R. Andes
- Dept of Medicine, University of Wisconsin
- Dept of Medical Microbiology and Immunology, University of Wisconsin
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Nobile CJ, Nett JE, Hernday AD, Homann OR, Deneault JS, Nantel A, Andes DR, Johnson AD, Mitchell AP. Biofilm matrix regulation by Candida albicans Zap1. PLoS Biol 2009; 7:e1000133. [PMID: 19529758 PMCID: PMC2688839 DOI: 10.1371/journal.pbio.1000133] [Citation(s) in RCA: 249] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Accepted: 05/12/2009] [Indexed: 01/06/2023] Open
Abstract
A biofilm is a surface-associated population of microorganisms embedded in a matrix of extracellular polymeric substances. Biofilms are a major natural growth form of microorganisms and the cause of pervasive device-associated infection. This report focuses on the biofilm matrix of Candida albicans, the major fungal pathogen of humans. We report here that the C. albicans zinc-response transcription factor Zap1 is a negative regulator of a major matrix component, soluble beta-1,3 glucan, in both in vitro and in vivo biofilm models. To understand the mechanistic relationship between Zap1 and matrix, we identified Zap1 target genes through expression profiling and full genome chromatin immunoprecipitation. On the basis of these results, we designed additional experiments showing that two glucoamylases, Gca1 and Gca2, have positive roles in matrix production and may function through hydrolysis of insoluble beta-1,3 glucan chains. We also show that a group of alcohol dehydrogenases Adh5, Csh1, and Ifd6 have roles in matrix production: Adh5 acts positively, and Csh1 and Ifd6, negatively. We propose that these alcohol dehydrogenases generate quorum-sensing aryl and acyl alcohols that in turn govern multiple events in biofilm maturation. Our findings define a novel regulatory circuit and its mechanism of control of a process central to infection.
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Affiliation(s)
- Clarissa J. Nobile
- Department of Microbiology, Columbia University, New York, New York, United States of America
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
| | - Jeniel E. Nett
- Department of Medicine, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Aaron D. Hernday
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
| | - Oliver R. Homann
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
| | - Jean-Sebastien Deneault
- Biotechnology Research Institute, National Research Council of Canada, Montreal, Quebec, Canada
| | - Andre Nantel
- Biotechnology Research Institute, National Research Council of Canada, Montreal, Quebec, Canada
| | - David R. Andes
- Department of Medicine, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Alexander D. Johnson
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
| | - Aaron P. Mitchell
- Department of Microbiology, Columbia University, New York, New York, United States of America
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
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