Phenotypic Profiling Reveals that Candida albicans Opaque Cells Represent a Metabolically Specialized Cell State Compared to Default White Cells

The white-opaque switch is a bistable, epigenetic transition affecting multiple traits in Candida albicans including mating, immunogenicity, and niche specificity. To compare how the two cell states respond to external cues, we examined the fitness, phenotypic switching, and filamentation properties...

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Main Authors: Ene, Iuliana V., Lohse, Matthew B., Morschhäuser, Joachim, Johnson, Alexander D., Bennett, Richard J., Vladu, Adrian Valentin
Other Authors: Massachusetts Institute of Technology. Department of Mathematics
Format: Article
Language:en_US
Published: American Society for Microbiology 2017
Online Access:http://hdl.handle.net/1721.1/107619
https://orcid.org/0000-0003-0722-304X
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author Ene, Iuliana V.
Lohse, Matthew B.
Morschhäuser, Joachim
Johnson, Alexander D.
Bennett, Richard J.
Vladu, Adrian Valentin
author2 Massachusetts Institute of Technology. Department of Mathematics
author_facet Massachusetts Institute of Technology. Department of Mathematics
Ene, Iuliana V.
Lohse, Matthew B.
Morschhäuser, Joachim
Johnson, Alexander D.
Bennett, Richard J.
Vladu, Adrian Valentin
author_sort Ene, Iuliana V.
collection MIT
description The white-opaque switch is a bistable, epigenetic transition affecting multiple traits in Candida albicans including mating, immunogenicity, and niche specificity. To compare how the two cell states respond to external cues, we examined the fitness, phenotypic switching, and filamentation properties of white cells and opaque cells under 1,440 different conditions at 25°C and 37°C. We demonstrate that white and opaque cells display striking differences in their integration of metabolic and thermal cues, so that the two states exhibit optimal fitness under distinct conditions. White cells were fitter than opaque cells under a wide range of environmental conditions, including growth at various pHs and in the presence of chemical stresses or antifungal drugs. This difference was exacerbated at 37°C, consistent with white cells being the default state of C. albicans in the mammalian host. In contrast, opaque cells showed greater fitness than white cells under select nutritional conditions, including growth on diverse peptides at 25°C. We further demonstrate that filamentation is significantly rewired between the two states, with white and opaque cells undergoing filamentous growth in response to distinct external cues. Genetic analysis was used to identify signaling pathways impacting the white-opaque transition both in vitro and in a murine model of commensal colonization, and three sugar sensing pathways are revealed as regulators of the switch. Together, these findings establish that white and opaque cells are programmed for differential integration of metabolic and thermal cues and that opaque cells represent a more metabolically specialized cell state than the default white state. IMPORTANCE Epigenetic transitions are an important mechanism by which microbes adapt to external stimuli. For Candida albicans, such transitions are crucial for adaptation to complex, fluctuating environments, and therefore contribute to its success as a human pathogen. The white-opaque switch modulates multiple C. albicans attributes, from sexual competency to niche specificity. Here, we demonstrate that metabolic circuits are extensively rewired between white and opaque states, so that the two cell types exhibit optimal fitness under different nutritional conditions and at different temperatures. We thereby establish that epigenetic events can profoundly alter the metabolism of fungal cells. We also demonstrate that epigenetic switching regulates filamentation and biofilm formation, two phenotypes closely associated with pathogenesis. These experiments reveal that white cells, considered the most clinically relevant form of C. albicans, are a “general-purpose” state suited to many environments, whereas opaque cells appear to represent a more metabolically specialized form of the species.
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spelling mit-1721.1/1076192022-09-29T12:06:47Z Phenotypic Profiling Reveals that Candida albicans Opaque Cells Represent a Metabolically Specialized Cell State Compared to Default White Cells Ene, Iuliana V. Lohse, Matthew B. Morschhäuser, Joachim Johnson, Alexander D. Bennett, Richard J. Vladu, Adrian Valentin Massachusetts Institute of Technology. Department of Mathematics Vladu, Adrian Valentin The white-opaque switch is a bistable, epigenetic transition affecting multiple traits in Candida albicans including mating, immunogenicity, and niche specificity. To compare how the two cell states respond to external cues, we examined the fitness, phenotypic switching, and filamentation properties of white cells and opaque cells under 1,440 different conditions at 25°C and 37°C. We demonstrate that white and opaque cells display striking differences in their integration of metabolic and thermal cues, so that the two states exhibit optimal fitness under distinct conditions. White cells were fitter than opaque cells under a wide range of environmental conditions, including growth at various pHs and in the presence of chemical stresses or antifungal drugs. This difference was exacerbated at 37°C, consistent with white cells being the default state of C. albicans in the mammalian host. In contrast, opaque cells showed greater fitness than white cells under select nutritional conditions, including growth on diverse peptides at 25°C. We further demonstrate that filamentation is significantly rewired between the two states, with white and opaque cells undergoing filamentous growth in response to distinct external cues. Genetic analysis was used to identify signaling pathways impacting the white-opaque transition both in vitro and in a murine model of commensal colonization, and three sugar sensing pathways are revealed as regulators of the switch. Together, these findings establish that white and opaque cells are programmed for differential integration of metabolic and thermal cues and that opaque cells represent a more metabolically specialized cell state than the default white state. IMPORTANCE Epigenetic transitions are an important mechanism by which microbes adapt to external stimuli. For Candida albicans, such transitions are crucial for adaptation to complex, fluctuating environments, and therefore contribute to its success as a human pathogen. The white-opaque switch modulates multiple C. albicans attributes, from sexual competency to niche specificity. Here, we demonstrate that metabolic circuits are extensively rewired between white and opaque states, so that the two cell types exhibit optimal fitness under different nutritional conditions and at different temperatures. We thereby establish that epigenetic events can profoundly alter the metabolism of fungal cells. We also demonstrate that epigenetic switching regulates filamentation and biofilm formation, two phenotypes closely associated with pathogenesis. These experiments reveal that white cells, considered the most clinically relevant form of C. albicans, are a “general-purpose” state suited to many environments, whereas opaque cells appear to represent a more metabolically specialized form of the species. 2017-03-21T15:03:22Z 2017-03-21T15:03:22Z 2016-11 2016-07 Article http://purl.org/eprint/type/JournalArticle 2150-7511 http://hdl.handle.net/1721.1/107619 Ene, Iuliana V. et al. “Phenotypic Profiling Reveals That Candida Albicans Opaque Cells Represent a Metabolically Specialized Cell State Compared to Default White Cells.” mBio 7.6 (2016): e01269-16. https://orcid.org/0000-0003-0722-304X en_US http://dx.doi.org/10.1128/mBio.01269-16 mBio Creative Commons Attribution 4.0 International License http://creativecommons.org/licenses/by/4.0/ application/pdf American Society for Microbiology American Society for Microbiology
spellingShingle Ene, Iuliana V.
Lohse, Matthew B.
Morschhäuser, Joachim
Johnson, Alexander D.
Bennett, Richard J.
Vladu, Adrian Valentin
Phenotypic Profiling Reveals that Candida albicans Opaque Cells Represent a Metabolically Specialized Cell State Compared to Default White Cells
title Phenotypic Profiling Reveals that Candida albicans Opaque Cells Represent a Metabolically Specialized Cell State Compared to Default White Cells
title_full Phenotypic Profiling Reveals that Candida albicans Opaque Cells Represent a Metabolically Specialized Cell State Compared to Default White Cells
title_fullStr Phenotypic Profiling Reveals that Candida albicans Opaque Cells Represent a Metabolically Specialized Cell State Compared to Default White Cells
title_full_unstemmed Phenotypic Profiling Reveals that Candida albicans Opaque Cells Represent a Metabolically Specialized Cell State Compared to Default White Cells
title_short Phenotypic Profiling Reveals that Candida albicans Opaque Cells Represent a Metabolically Specialized Cell State Compared to Default White Cells
title_sort phenotypic profiling reveals that candida albicans opaque cells represent a metabolically specialized cell state compared to default white cells
url http://hdl.handle.net/1721.1/107619
https://orcid.org/0000-0003-0722-304X
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