Integrated transcriptomic analysis of Trichosporon asahii uncovers the core genes and pathways of fluconazole resistance
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ABSTRACT: We performed a series of fluconazole (FLC) perturbation experiments for two T. asahii strains, a clinical isolate stain CBS2479 (T2) and an environmental isolate strain CBS8904 (T8), to uncover potential genes and pathways involved in FLC resistance.
Project description:Transcriptional profiling of Candida albicans comparing fluconazole treated cells with fluconazole- and berberine-treated cells, as well untreated cells with berberine treated cells Three different clinical FLC-resistant strains (0304103, 01010 and 632) were selected to carry out the expression profile microarray. Two-condition experiment, fluconazole-treated vs. fluconazole- and berberine-treated cells, and untreated cells vs. berberine-treated cells. Biological replicates: 3 control, 3 transfected, independently grown and harvested. One replicate per array.
Project description:QUANT-seq approach was utilized to determine the gene expression in the transcriptome of C. albicans treated with the solvent control DMSO or the antifungal drug fluconazole (FLC). Biological triplicates of C. albicans grown in YPD medium treated with either DMSO or 3 µg/ml fluconazole for 30 minutes at 37˚C were harvested and total RNA was isolated using standard procedures (hot phenol method).
Project description:Azole resistance was induced in vitro by growth of a susceptible C. parapsilosis isolate in the presence of fluconazole. Whole genome microarrays were used to compare the transcriptional response of the fluconazole-resistant and susceptible isolates.
Project description:Fluconazole (FLC), a triazole antifungal drug, is widely used for the maintenance therapy of cryptococcal meningoencephalitis, the most common opportunistic infection in AIDS patients, but this usage predisposes to the appearance of FLC resistance, especially in patients with no or limited access to highly active antiretroviral therapy. We used microarray analysis to examine changes in the gene expression profile of C. neoformans reference strain H99 (serotype A) following exposure to FLC in order to study the adaptive cellular responses to drug stress. Simultaneous analysis of over 6,823 C. neoformans gene transcript levels revealed that 476 genes were responsive to FLC. Up-regulated expression was observed, as expected, for genes involved in the ergosterol biosynthesis, including ERG13, ERG1, ERG7, ERG25, ERG2, ERG3, ERG5, and that encoding the azole target, ERG11, but also for the gene SRE1, that encodes a well-known regulator of sterol homeostasis in C. neoformans. In addition, several genes such as those involved in a wide variety of important cellular processes (i.e., lipid and fatty acid metabolism, cell wall maintenance, stress, virulence, etc.), were found to be up-regulated in response to fluconazole treatment. Some of these genes may represent potential therapeutic targets to be exploited in anticryptococcal therapy. Conversely, expression of AFR1, the major transporter of azoles in C. neoformans, was shown to be not affected by exposure to FLC, thus suggesting a minor involvement in the C. neoformans short-term adaptation to the azole drug. We studied the transient response of C. neoformans to fluconazole by analyzing differences in gene expression prior to and after exposure of strain H99. Three biological replicates were performed for each condition (FLC-exposed and -not exposed (controls)). The cells were exposed to 10 µg of FLC/ml (1/2 x MIC) or distilled water (controls) for one doubling time (90 min).
Project description:Azole resistance was induced in vitro by growth of a susceptible C. parapsilosis isolate in the presence of fluconazole. Whole genome microarrays were used to compare the transcriptional response of the fluconazole-resistant and susceptible isolates. Transcriptional profile of in vitro derived fluconazole resistant isolate of C. parapsilosis (BC014FLC) compared to susceptible isolate (BC014S). Cell were grown in YPD medium in normoxia at 35 degrees. Each strain was labelled with Cy3 or Cy5. Overall, 4 independent biological replicates were compared; 2 dye swaps were performed to normalize dye effects.
Project description:Fluconazole (FLC), a triazole antifungal drug, is widely used for the maintenance therapy of cryptococcal meningoencephalitis, the most common opportunistic infection in AIDS patients, but this usage predisposes to the appearance of FLC resistance, especially in patients with no or limited access to highly active antiretroviral therapy. We used microarray analysis to examine changes in the gene expression profile of C. neoformans reference strain H99 (serotype A) following exposure to FLC in order to study the adaptive cellular responses to drug stress. Simultaneous analysis of over 6,823 C. neoformans gene transcript levels revealed that 476 genes were responsive to FLC. Up-regulated expression was observed, as expected, for genes involved in the ergosterol biosynthesis, including ERG13, ERG1, ERG7, ERG25, ERG2, ERG3, ERG5, and that encoding the azole target, ERG11, but also for the gene SRE1, that encodes a well-known regulator of sterol homeostasis in C. neoformans. In addition, several genes such as those involved in a wide variety of important cellular processes (i.e., lipid and fatty acid metabolism, cell wall maintenance, stress, virulence, etc.), were found to be up-regulated in response to fluconazole treatment. Some of these genes may represent potential therapeutic targets to be exploited in anticryptococcal therapy. Conversely, expression of AFR1, the major transporter of azoles in C. neoformans, was shown to be not affected by exposure to FLC, thus suggesting a minor involvement in the C. neoformans short-term adaptation to the azole drug.
Project description:In the pathogenic yeast Candida albicans, the zinc cluster transcription factor Upc2p has been shown to regulate expression of ERG11 and other genes involved in ergosterol biosynthesis upon exposure to azole antifungals. ERG11 encodes lanosterol demethylase, the target enzyme of this antifungal class. Over-expression of UPC2 reduces azole susceptibility, whereas its disruption results in hypersusceptibility to azoles and reduced accumulation of exogenous sterols. Constitutive up-regulation of ERG11 is a major cause of resistance to fluconazole in clinical isolates of C. albicans, yet the mechanism for this has yet to be determined. Using genome-wide gene expression profiling, we found UPC2 and other genes involved in ergosterol biosynthesis to be coordinately up-regulated with ERG11 in a fluconazole resistant clinical isolate as compared with a matched susceptible isolate from the same patient. Sequence analysis of the UPC2 alleles of these isolates revealed that the resistant isolate contained a single nucleotide substitution in one UPC2 allele that resulted in a G648D exchange in the encoded protein. Introduction of the mutated allele into a drug susceptible strain resulted in constitutive up-regulation of ERG11 and increased resistance to fluconazole. By comparing the gene expression profiles of the fluconazole resistant isolate and of strains carrying wild-type and mutated UPC2 alleles, we identified target genes that are controlled by Upc2p. Here we show for the first time that a gain-of-function mutation in UPC2 leads to increased expression of ERG11 and imparts resistance to fluconazole in clinical isolates of C. albicans. Keywords: genome-wide expression profiling
Project description:Trichosporon asahii (T. asahii) has emerged as a dangerous pathogen that causes rare but life-threatening infections. Its resistance to certain antifungal agents makes it difficult to treat, especially for patients undergoing long-term antibiotic therapy. In this study, we performed a series of fluconazole (FLC) perturbation experiments for two T. asahii strains, a clinical isolate stain CBS 2479 (T2) and an environmental isolate strain CBS 8904 (T8), to uncover potential genes and pathways involved in FLC resistance. We achieved 10 transcriptomes of T2 and T8 that were based on dose and time series of FLC perturbations. Systematic comparisons of the transcriptomes revealed 32 T2 genes and 25 T8 genes that are highly sensitive to different FLC perturbations. In both T2 and T8 strains with the phenotype of FLC resistance, the processes of oxidation-reduction and transmembrane transport were detected to be significantly changed. The antifungal susceptibility testing of FLC and penicillin revealed their resistance pathways are merged. Accumulated mutations were found in 564 T2 and 225 T8 genes, including four highly mutated genes that are functionally related to the target of rapamycin complex (TOR). Our study provides abundant data towards genome-wide understanding of the molecular basis of FLC resistance in T. asahii.
Project description:Purpose: Compare the fluconazole-induced transcriptome of isogenic wild-type and upc2A null cells. Methods: Prepare total RNA from wild-type and upc2A null cells grown under unstressed conditions or challenged with 50 microgram/ml fluconazole for 6 hours. Use standard RNA-seq to evaluate and compare the transcriptomic changes caused by fluconazole in the presence or absence of UPC2A. Results: These data established that over 100 genes were induced by fluconazole in a UPC2A-dependent manner. However, most fluconazole-induced genes (>500) did not require the presence of UPC2A. Fluconazole-induced genes included the expected genes involved in ergosterol biosynthesis but also large number of plasma membrane-localized transporters. Conclusions: These data suggest that Upc2A provided transcriptional co-regulation between membrane transporters and the lipid environment in which these proteins function. A significant portion of the fluconazole-induced transcriptome does not require the presence of Upc2A, suggesting the presence of other transcriptional circuits responsive to this pharmacologic block of ergosterol biosynthesis.