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:Azole antifungals are widely used to control fungal infection, yet resistance mechanisms beyond drug efflux and target modification remain insufficiently understood. Here, we identified the Guided Entry of Tail-anchored proteins (GET) pathway as a conserved regulator of azole susceptibility in Neurospora crassa and Aspergillus fumigatus. Deletion or dysfunction of the core GET components Get-3 or Get-4 confers resistance to multiple azoles without impairing hyphal growth or sporulation. Mechanistically, GET deficiency neither reduced intracellular accumulation nor altered drug efflux and target expression or total ergosterol levels. Instead, GET-deficient strains displayed significantly reduced accumulation of the toxic sterol intermediate 14α-methyl-3,6-diol under azole stress, indicating a potential bypass of azole-induced sterol toxicity. Proximity labeling and functional validation indicated that GET deficiency perturbs the trafficking of multiple azole-resistance-associated proteins, including the key tail-anchored protein transporter Emp-47 and mitochondrial Cox subunits Cox-4 and Cox-15, which deletion enhanced azole resistance. Transcriptomic and functional analysis further revealed that GET disruption altered the expression of some azole resistance-associated genes, which involve in membrane transport, metabolism, and cell wall organization, independent of canonical stress pathways. In this study, a total of 17 new genes that modulate azole susceptibility were identified. Collectively, our findings uncover a non-classical mechanism of azole resistance mediated by GET-dependent protein trafficking and metabolic adaptation, conserved across filamentous fungi.
2026-04-23 | GSE328637 | GEO
Project description:Azole antifungals are widely used to control fungal infection, yet resistance mechanisms beyond drug efflux and target modification remain insufficiently understood. Here, we identified the Guided Entry of Tail-anchored proteins (GET) pathway as a conserved regulator of azole susceptibility in Neurospora crassa and Aspergillus fumigatus. Deletion or dysfunction of the core GET components Get-3 or Get-4 confers resistance to multiple azoles without impairing hyphal growth or sporulation. Mechanistically, GET deficiency neither reduced intracellular accumulation nor altered drug efflux and target expression or total ergosterol levels. Instead, GET-deficient strains displayed significantly reduced accumulation of the toxic sterol intermediate 14α-methyl-3,6-diol under azole stress, indicating a potential bypass of azole-induced sterol toxicity. Proximity labeling and functional validation indicated that GET deficiency perturbs the trafficking of multiple azole-resistance-associated proteins, including the key tail-anchored protein transporter Emp-47 and mitochondrial Cox subunits Cox-4 and Cox-15, which deletion enhanced azole resistance. Transcriptomic and functional analysis further revealed that GET disruption altered the expression of some azole resistance-associated genes, which involve in membrane transport, metabolism, and cell wall organization, independent of canonical stress pathways. In this study, a total of 17 new genes that modulate azole susceptibility were identified. Collectively, our findings uncover a non-classical mechanism of azole resistance mediated by GET-dependent protein trafficking and metabolic adaptation, conserved across filamentous fungi.
2026-04-01 | PXD076447 |
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: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 Acetylation-dependent (Ac/) N-degron pathway degrades proteins through recognition of their acetylated N-termini (Nt) by E3-ligases called Ac/N-recognins. To date, specific Ac/N-recognins have not been defined in plants. Here we used molecular, genetic, and multi-omics approaches to characterise potential roles for Arabidopsis (Arabidopsis thaliana) DEGRADATION OF ALPHA2 10 (DOA10)-like E3-ligases in the Nt-acetylation-(NTA-) dependent turnover of proteins at global and protein-specific scales. Arabidopsis has two ER-localised DOA10-like proteins. AtDOA10A, but not the Brassicaceae-specific AtDOA10B, can compensate for loss of yeast (Saccharmoyces cerevisiae) ScDOA10 function. Transcriptome and Nt-acetylome profiling of an Atdoa10a/b RNAi mutant revealed no obvious differences in the global NTA profile compared to wildtype, suggesting that AtDOA10s do not regulate the bulk turnover of NTA substrates. Using protein steady-state and cycloheximide-chase degradation assays in yeast and Arabidopsis, we showed that turnover of ER-localised squalene epoxidase 1 (AtSQE1), a critical sterol biosynthesis enzyme, is mediated by AtDOA10s. Degradation of AtSQE1 in planta did not depend on NTA, but Nt-acetyltransferases indirectly impacted its turnover in yeast, indicating kingdom-specific differences in NTA and cellular proteostasis. Our work suggests that, in contrast to yeast and mammals, targeting of Nt-acetylated proteins is not a major function of DOA10-like E3 ligases in Arabidopsis and provides further insight into plant ERAD and the conservation of regulatory mechanisms controlling sterol biosynthesis in eukaryotes.
2023-11-13 | GSE236282 | 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: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:We performed bulk RNA-seq on squalene/M-CSF-treated macrophages to compute the fold change of genes in the squalene/M-CSF compared to M-CSF alone treated macrophages. We then looked at the distribution of the log fold changes in the skin-derived TREM2 (607 genes) and M2-like (709 genes) macrophage scRNA-seq signatures. We found that the TREM2 gene signature was more highly induced by squalene/M-CSF than the M2-like macrophage signature. In these squalene-induced macrophages, we found upregulation of several of the lipid metabolism and pro-inflammatory genes present in the skin-derived TREM2 macrophage gene signature.
2021-11-09 | GSE188363 | GEO
Project description:Background and Purpose: Squalene is the main hydrocarbon present in extra virgin olive oil and it has been reported to have anti-steatotic properties in different animal models. The aims of this study were to investigate its effects on liver transcriptomics in Male C57BL/6J Apoe-deficient mice. Experimental Approaches: Male C57BL/6J Apoe-deficient mice were fed a purified Western diet with or without squalene during 11 weeks and hepatic squalene content was assessed. Hepatic transcriptomic changes were studied and confirmed by RT-qPCR. Key Results: Squalene supplementation increased its hepatic content. The Cyp2b10 and Cyp2c55 gene expressions were significantly up-regulated by the squalene intake in all animal models, with independence of sex, sexual hormones, dietary fat content, genetic background and dose, and were strongly associated with antioxidant defense capacity and with lipid content and composition. Conclusions and Implications: hepatic squalene exerts its activity through overexpression of these cytochromes and their changes in virgin olive oil diets may be due to squalene.
2021-04-30 | GSE145343 | GEO