Antagonism between two mechanisms of antifungal drug resistance
Ontology highlight
ABSTRACT:
ORGANISM(S): Saccharomyces cerevisiae
PROVIDER: GSE4261 | GEO | 2006/07/15
SECONDARY ACCESSION(S): PRJNA94857
REPOSITORIES: GEO
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Project description:Purpose: We compared the expression profile of three fluconazole resistant clinical isolates to two fluconazole sensitive clinical isolates, from the same patient, all containing mutation in the trancription factor Mrr1, to define the Mrr1 regulon in Candida lusitaniae.
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2017-07-18 | GSE60121 | GEO
Project description:We examined the gene expression changes resulting from the evolution of resistance in experimental populations of the yeast Saccharomyces cerevisiae subjected to two antifungal drugs, fluconazole (FLC) and amphotericin B (AmB). Fluconazole resistance may involve increased efflux or changes in sterol metabolism, while AmB resistance generally involves changes in sterol metabolism; for all of these types of resistance, the gene expression changes are extensive. The goal of these experiments was to test whether failure of gene expression changes all downstream of the original mutation for drug resistance would affect the ability of a mutant cell to evolve and/or to support a drug-resistant phenotype.
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Project description:In Candida albicans, the transcription factor Upc2 is central to the regulation of ergosterol biosynthesis. UPC2-activating mutations contribute to azole resistance, whereas disruption increases azole susceptibility. In the present study, we investigated the relationship of UPC2 to fluconazole susceptibility, particularly in azole-resistant strains. In addition to the reduced fluconazole MIC previously observed with UPC2 disruption, we observed a lower minimum fungicidal concentration (MFC) for a upc2M-NM-^T/M-NM-^T mutant than for its azole-susceptible parent, SC5314. Moreover, the upc2M-NM-^T/M-NM-^T mutant was unable to grow on a solid medium containing 10 M-BM-5g/ml fluconazole and exhibited increased susceptibility and a clear zone of inhibition by Etest. Time-kill analysis showed higher fungistatic activity against the upc2M-NM-^T/M-NM-^T mutant than against SC5314. UPC2 disruption in strains carrying specific resistance mutations also resulted in reduced MICs and MFCs. UPC2 disruption in a highly azole resistant clinical isolate containing multiple resistance mechanisms likewise resulted in a reduced MIC and MFC. This mutant was unable to grow on a solid medium containing 10 M-BM-5g/ml fluconazole and exhibited increased susceptibility and a clear zone of inhibition by Etest. Time-kill analysis showed increased fungistatic activity against the upc2M-NM-^T/M-NM-^T mutant in the resistant background. Microarray analysis showed attenuated induction by fluconazole of genes involved in sterol biosynthesis, iron transport, or iron homeostasis in the absence of UPC2. Taken together, these data demonstrate that the UPC2 transcriptional network is universally essential for azole resistance in C. albicans and represents an attractive target for enhancing azole antifungal activity. We examined the genome-wide gene expression profiles of the wild-type parent strain SC5314 and its upc2M-NM-^T/M-NM-^T derivative in response to fluconazole in order to identify genes whose expression in response to fluconazole is influenced by Upc2.
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Project description:In Candida albicans, the transcription factor Upc2 is central to the regulation of ergosterol biosynthesis. UPC2-activating mutations contribute to azole resistance, whereas disruption increases azole susceptibility. In the present study, we investigated the relationship of UPC2 to fluconazole susceptibility, particularly in azole-resistant strains. In addition to the reduced fluconazole MIC previously observed with UPC2 disruption, we observed a lower minimum fungicidal concentration (MFC) for a upc2Δ/Δ mutant than for its azole-susceptible parent, SC5314. Moreover, the upc2Δ/Δ mutant was unable to grow on a solid medium containing 10 µg/ml fluconazole and exhibited increased susceptibility and a clear zone of inhibition by Etest. Time-kill analysis showed higher fungistatic activity against the upc2Δ/Δ mutant than against SC5314. UPC2 disruption in strains carrying specific resistance mutations also resulted in reduced MICs and MFCs. UPC2 disruption in a highly azole resistant clinical isolate containing multiple resistance mechanisms likewise resulted in a reduced MIC and MFC. This mutant was unable to grow on a solid medium containing 10 µg/ml fluconazole and exhibited increased susceptibility and a clear zone of inhibition by Etest. Time-kill analysis showed increased fungistatic activity against the upc2Δ/Δ mutant in the resistant background. Microarray analysis showed attenuated induction by fluconazole of genes involved in sterol biosynthesis, iron transport, or iron homeostasis in the absence of UPC2. Taken together, these data demonstrate that the UPC2 transcriptional network is universally essential for azole resistance in C. albicans and represents an attractive target for enhancing azole antifungal activity.
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Project description:This study explored the transcriptional change of Candida glabrata cells due to GCN5 deletion. We also compared the transcriptional responses to fluconazole and micafungin in WT and gcndelta cells relative to respective no drug controls.
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Project description:Here we show that the human fungal pathogen Mucor circinelloides develops spontaneous resistance to the antifungal drug FK506 via two distinct mechanisms. One involves Mendelian mutations that confer stable drug resistance and the other via an epigenetic RNA interference (RNAi)-mediated pathway that results in unstable drug resistance. The peptidyl-prolyl isomerase FKBP12 interacts with FK506 to form a complex that inhibits the protein phosphatase calcineurin. In M. circinelloides, inhibition of calcineurin by FK506 blocks the transition to hyphae and enforces yeast growth. Mutations in the fkbA gene encoding FKBP12 or the calcineurin cnbR or cnaA genes confer FK506 resistance, restoring hyphal growth in the presence of this drug. In parallel, RNAi is spontaneously triggered to silence the FKBP12 fkbA gene, giving rise to drug-resistant epimutants. FK506-resistant epimutants readily reverted to the drug-sensitive wild type (WT) phenotype when selection was released by growth without drug. High-throughput small RNA (sRNA) sequencing showed abundant sRNA antisense to fkbA only in the epimutants and not in the WT or revertant strains. Analysis of RNAi mutants revealed components required for the establishment of drug resistant epimutants as well as other factors that constrain or reverse the epimutation pathway. Silencing involves generation of a double stranded RNA trigger intermediate using the fkbA mature mRNA as template. These results uncover a novel epigenetic RNAi-based epimutation mechanism controlling phenotypic plasticity, with possible implications for antimicrobial drug resistance and RNAi regulatory mechanisms in fungi and other eukaryotes.
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