Role of squalene hopene cyclase in azole-resistance and virulence of Aspergillus fumigatus
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ABSTRACT:
ORGANISM(S): Aspergillus fumigatus
PROVIDER: GSE317610 | GEO | 2026/02/03
REPOSITORIES: GEO
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Project description:Role of squalene hopene cyclase in azole-resistance and virulence of Aspergillus fumigatus
| PRJNA1414538 | ENA
Project description:The present study describes a novel mechanism of antifungal resistance affecting the susceptibility of both the azole and echinocandin antifungals in an azole-resistant isolate from a matched pair of C. parapsilosis isolates obtained from a patient with prosthetic valve endocarditis. Transcriptome analysis indicated differential expression of several genes in the resistant isolate including upregulation of ERG1, ERG2, ERG5, ERG6, ERG11, ERG24, ERG25, ERG27, DAP1 and UPC2, of the ergosterol biosynthesis pathway. Whole genome sequencing revealed a mutation in the ERG3 gene leading to a G111R amino acid substitution in the resistant isolate. Subsequent introduction of this allele in the native ERG3 locus in the susceptible isolate resulted in a fluconazole MIC of >64 mg/ml and a caspofungin MIC of 8 mg/ml. Corresponding allelic replacement of the wildtype allele for the mutant allele in the resistant isolate resulted in a drop in MIC to 1 mg/ml for both fluconazole and caspofungin. Sterol profiles indicated a loss of sterol demethylase activity as a result of this mutation. This work demonstrate that this G111R mutation is wholly responsible for the resistant phenotype in the C. parapsilosis resistant isolate and is the first report of this multidrug resistance mechanism.
2017-05-25 | GSE98986 | GEO
Project description:The limited number of antifungals and the emergence of multidrug-resistant Candida auris pose a significant challenge to human medicine. Here, we utilized combinatorial drug therapy as an approach to augment the activity of current azole antifungals against C. auris. We evaluated the fluconazole chemosensitization activity of 1547 FDA-approved drugs and clinical molecules against an azole-resistant strain of C. auris. This led to the discovery that lopinavir, an antiviral drug, is a potent agent capable of sensitizing C. auris to the effect of azole antifungals. At a therapeutically achievable concentration (4-8 µg/ml), lopinavir exhibited potent synergistic interactions with azole drugs, particularly with itraconazole, against C. auris (ΣFICI ranged from 0.05-0.50). The lopinavir/itraconazole combination enhanced the survival rate of C. auris-infected Caenorhabditis elegans by 90% and reduced the fungal burden in infected nematodes by 88.5% (p < 0.05). Moreover, lopinavir enhanced the antifungal activity of itraconazole against other medically important Candida species including C. albicans, C. tropicalis, C. glabrata, C. tropicalis, and C. parapsilosis. Comparative transcriptomic profiling revealed that lopinavir interferes with glucose permeation and ATP synthesis. This compromises the function of the efflux pumps presents in C. auris enhancing sensitivity to azole antifungals, as demonstrated by Nile red efflux assays. This study presents lopinavir as a novel, potent and broad-spectrum azole chemosensitizing agent that warrants further investigation against recalcitrant Candida infections.
2020-10-06 | GSE148341 | GEO
Project description:Ergosterol, a key lipid component of fungal membranes, has its homeostasis predominantly maintained through membrane-associated mechanisms, yet the role of the many transmembrane proteins in regulating sterol homeostasis remains poorly understood. Here, we systematically screened 1,042 viable transmembrane protein mutants in Neurospora crassa, and identified 180 that exhibited altered sensitivity to one or more sterol biosynthesis inhibitors. Further analysis pinpointed three genes, cax-4, chol-6 and NCU01826, as required for the upregulation of erg11 upon azole treatment. CAX-4, a conserved dolichyl pyrophosphate phosphatase, was further characterized. Deletion of this gene leads to hypersensitivity to ketoconazole and amorolfine, and impairs the proper expression of membrane and extracellular proteins. Notably, CAX-4 was required for the transcriptional induction of core ergosterol biosynthetic genes (e.g., erg11, erg6, erg24) and sterol metabolism under azole stress. This phenotype was linked to reduced levels of NcSR, a key transcription factor in sterol biosynthesis regulation, at both the mRNA and protein level. Mechanistically, CAX-4 maintains protein homeostasis via N-glycosylation, as Tunicamycin treatment phenocopied its deletion. Above all, by characterizing key transmembrane protein in sterol biosynthesis regulation, our study unveils a CAX-4 integrated crosstalk between dolichol-mediated protein N-glycosylation and sterol biosynthesis regulation, thus offering novel insights into sterol homeostasis and pointing to potential targets for the development of antifungal strategies.
2025-12-02 | GSE311794 | GEO
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.
2014-05-24 | GSE57929 | GEO
Project description:The widespread use of azole antifungal drugs in agriculture and clinical settings has led to serious drug resistance issues. Under azole treatment, resistant strains can upregulate the expression of the azole drug target 14α-demethylase ERG11 through transcription factors to alleviate the stress induced by sterol synthesis inhibition, which is a common resistance mechanism. Additionally, the currently reported regulatory factors related to resistance are not sufficient to explain all resistance issues. In this study, we constructed a GFP gene reporter system based on the erg11 promoter in the model filamentous fungus, Neurospora crassa, and identified a key region of the promoter that governs the erg11 response to azole drug by stepwise deletion. Using specific probes for DNA pulldown and combined with phenotype analysis, we identified a protein, Crf4-3, containing a PWWP domain that has a positive regulatory effect. Specific deletion of Crf4-3 leads to hypersensitivity to azole drugs and loss of transcriptional response of erg11 and erg6 to ketoconazole. Furthermore, the basal expression of erg1, erg11, erg25, and erg3A is affected by the deletion of crf4-3. Crf4-3 homologs are widely present in the Pezizomycotina fungi. Deletion of the homologous protein of Crf4-3 in Aspergillus fumigatus also significantly reduced sensitivity to azole drugs like voriconazole by reducing the transcriptional response of erg11. In summary, our study revealed a new regulatory factor Crf4-3 involved in the azole stress response in filamentous fungi and its mechanism, providing new insights into understanding the mechanisms of azole drug resistance.
2024-09-15 | GSE272185 | GEO
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.
2014-05-24 | E-GEOD-57929 | biostudies-arrayexpress
Project description:Fusarium verticillioides is a significant agricultural pathogen and an emerging causative agent of invasive fusariosis in clinical settings. Fusarium species frequently exhibit resistance to available antifungal agents, yet the molecular mechanisms underlying azole resistance remain poorly characterized. In this study, we identified the Zn(II)2Cys6 transcription factor FvADS-1 as a positive regulator of the azole stress response in F. verticillioides. The transcription of FvADS-1 was significantly induced by ketoconazole (KTC), and its deletion increased the susceptibility to multiple azole compounds. Mechanically, FvADS-1 positively regulates the KTC-induced expression of genes encoding ABC transporters and ergosterol biosynthesis enzymes, thereby modulating intracellular KTC accumulation and sterol homeostasis under azole stress. Furthermore, FvADS-1 positively regulates the transcriptional response of peroxisomal genes and contributes to fungal tolerance to oxidative stress. Notably, deletion of FvADS-1 attenuates the virulence of F. verticillioides on maize.
2025-12-31 | GSE315078 | GEO
Project description:This study investigated get3 mutant yeast cell. Proteins of the GET pathway are involved in targeting of C-terminally anchored transmembrane proteins and protection against lipotoxicity. Get3 cells revealed an altered ergosterol production and susceptibility towards a sterol synthesis inhibiting drug terbinafine. Furthermore, we identified a member of a non-canonical GET pathway client, a monotopic membrane protein squalene monooxygenase Erg1 that may be responsible for the susceptibility of Get3 mutant to lipotoxic agents.
2022-06-09 | PXD027705 | Pride
Project description:Genome sequence data results are reported from experimental and bioinfomatic work using the technique 'Bulk Segregant Analysis' to determine the genetic basis of observed resistance to the azole antifungal compound itraconazole in the opportunistic fungal pathogen Aspergillus fumigatus.
2022-05-11 | GSE193956 | GEO