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

View Article: PubMed Central - PubMed

ABSTRACT

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.

No MeSH data available.


Related in: MedlinePlus

Glucose plays a complex role in regulating white-opaque transitions. (A) Hierarchical clustering analysis of the four experimental data sets (white/opaque cells at 25°C/37°C) grown on 18 different sugars including glucose, galactose, fructose, mannose, maltose, lactose, sucrose, GlcNAc variants, sorbitol, and mannitol. A clustergram is included at the top of the heat map. The location for opaque cells grown with glucose at 37°C is highlighted in red. (B and C) Impact of glucose on white-to-opaque switching at 25°C (B) and on opaque cell stability at 37°C (C). Phenotypic transitions were assessed after growth on plates containing synthetic complete medium (SC) supplemented with 1% mannitol (M) or 1% mannitol plus 1% glucose (M+G). Switching was quantified after 7 or 8 days at 22 to 25°C or 3 or 4 days at 37°C (asterisks denote significant differences [P < 0.05] between the M and M+G values). Results represent averaged data from four to six biological replicates. (D) Glucose sensing and signaling pathways in C. albicans. Pathways were adapted from reference 62 with additional components included based on homology with signaling pathways in S. cerevisiae. PKA, protein kinase A; cAMP, cyclic AMP. (E and F) Impact of glucose on white-to-opaque switching at 25°C (E) and opaque cell stability at 37°C (F) for gal4Δ, gpa2Δ, hgt4Δ, and efg1Δ deletion strains. Phenotypic transitions were assessed after growth on SCM or SCM+G medium for 7 or 8 days at 25°C or for 3 or 4 days at 37°C (asterisks denote significant differences [P < 0.05] relative to the values for control strains).
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fig6: Glucose plays a complex role in regulating white-opaque transitions. (A) Hierarchical clustering analysis of the four experimental data sets (white/opaque cells at 25°C/37°C) grown on 18 different sugars including glucose, galactose, fructose, mannose, maltose, lactose, sucrose, GlcNAc variants, sorbitol, and mannitol. A clustergram is included at the top of the heat map. The location for opaque cells grown with glucose at 37°C is highlighted in red. (B and C) Impact of glucose on white-to-opaque switching at 25°C (B) and on opaque cell stability at 37°C (C). Phenotypic transitions were assessed after growth on plates containing synthetic complete medium (SC) supplemented with 1% mannitol (M) or 1% mannitol plus 1% glucose (M+G). Switching was quantified after 7 or 8 days at 22 to 25°C or 3 or 4 days at 37°C (asterisks denote significant differences [P < 0.05] between the M and M+G values). Results represent averaged data from four to six biological replicates. (D) Glucose sensing and signaling pathways in C. albicans. Pathways were adapted from reference 62 with additional components included based on homology with signaling pathways in S. cerevisiae. PKA, protein kinase A; cAMP, cyclic AMP. (E and F) Impact of glucose on white-to-opaque switching at 25°C (E) and opaque cell stability at 37°C (F) for gal4Δ, gpa2Δ, hgt4Δ, and efg1Δ deletion strains. Phenotypic transitions were assessed after growth on SCM or SCM+G medium for 7 or 8 days at 25°C or for 3 or 4 days at 37°C (asterisks denote significant differences [P < 0.05] relative to the values for control strains).

Mentions: HCA analysis revealed that opaque cells grown in the presence of glucose at 37°C clustered separately from opaque cells grown on most other C sources (Fig. 5B). This was true even when comparing growth on glucose versus growth on other sugars (including fructose, mannose, sucrose, and GlcNAc variants; Fig. 6A). This was unexpected as glucose is a key regulator of metabolism and filamentation in C. albicans and is thought to be metabolized similarly to fructose and galactose (60–65).


Phenotypic Profiling Reveals that Candida albicans Opaque Cells Represent a Metabolically Specialized Cell State Compared to Default White Cells
Glucose plays a complex role in regulating white-opaque transitions. (A) Hierarchical clustering analysis of the four experimental data sets (white/opaque cells at 25°C/37°C) grown on 18 different sugars including glucose, galactose, fructose, mannose, maltose, lactose, sucrose, GlcNAc variants, sorbitol, and mannitol. A clustergram is included at the top of the heat map. The location for opaque cells grown with glucose at 37°C is highlighted in red. (B and C) Impact of glucose on white-to-opaque switching at 25°C (B) and on opaque cell stability at 37°C (C). Phenotypic transitions were assessed after growth on plates containing synthetic complete medium (SC) supplemented with 1% mannitol (M) or 1% mannitol plus 1% glucose (M+G). Switching was quantified after 7 or 8 days at 22 to 25°C or 3 or 4 days at 37°C (asterisks denote significant differences [P < 0.05] between the M and M+G values). Results represent averaged data from four to six biological replicates. (D) Glucose sensing and signaling pathways in C. albicans. Pathways were adapted from reference 62 with additional components included based on homology with signaling pathways in S. cerevisiae. PKA, protein kinase A; cAMP, cyclic AMP. (E and F) Impact of glucose on white-to-opaque switching at 25°C (E) and opaque cell stability at 37°C (F) for gal4Δ, gpa2Δ, hgt4Δ, and efg1Δ deletion strains. Phenotypic transitions were assessed after growth on SCM or SCM+G medium for 7 or 8 days at 25°C or for 3 or 4 days at 37°C (asterisks denote significant differences [P < 0.05] relative to the values for control strains).
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fig6: Glucose plays a complex role in regulating white-opaque transitions. (A) Hierarchical clustering analysis of the four experimental data sets (white/opaque cells at 25°C/37°C) grown on 18 different sugars including glucose, galactose, fructose, mannose, maltose, lactose, sucrose, GlcNAc variants, sorbitol, and mannitol. A clustergram is included at the top of the heat map. The location for opaque cells grown with glucose at 37°C is highlighted in red. (B and C) Impact of glucose on white-to-opaque switching at 25°C (B) and on opaque cell stability at 37°C (C). Phenotypic transitions were assessed after growth on plates containing synthetic complete medium (SC) supplemented with 1% mannitol (M) or 1% mannitol plus 1% glucose (M+G). Switching was quantified after 7 or 8 days at 22 to 25°C or 3 or 4 days at 37°C (asterisks denote significant differences [P < 0.05] between the M and M+G values). Results represent averaged data from four to six biological replicates. (D) Glucose sensing and signaling pathways in C. albicans. Pathways were adapted from reference 62 with additional components included based on homology with signaling pathways in S. cerevisiae. PKA, protein kinase A; cAMP, cyclic AMP. (E and F) Impact of glucose on white-to-opaque switching at 25°C (E) and opaque cell stability at 37°C (F) for gal4Δ, gpa2Δ, hgt4Δ, and efg1Δ deletion strains. Phenotypic transitions were assessed after growth on SCM or SCM+G medium for 7 or 8 days at 25°C or for 3 or 4 days at 37°C (asterisks denote significant differences [P < 0.05] relative to the values for control strains).
Mentions: HCA analysis revealed that opaque cells grown in the presence of glucose at 37°C clustered separately from opaque cells grown on most other C sources (Fig. 5B). This was true even when comparing growth on glucose versus growth on other sugars (including fructose, mannose, sucrose, and GlcNAc variants; Fig. 6A). This was unexpected as glucose is a key regulator of metabolism and filamentation in C. albicans and is thought to be metabolized similarly to fructose and galactose (60–65).

View Article: PubMed Central - PubMed

ABSTRACT

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&deg;C and 37&deg;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&deg;C, consistent with white cells being the default state of C.&nbsp;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&deg;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.

No MeSH data available.


Related in: MedlinePlus