Aspergillus fumigatus
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PROVIDER: PRJNA128985 | ENA |
REPOSITORIES: ENA
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Project description:Iron is an essential cofactor for a wide range of cellular processes. Previous studies have shown that siderophore-mediated uptake and intracellular handling of iron are crucial for virulence of Aspergillus fumigatus. Here we show that the bzip-type transcription factor HapX plays a crucial role in the transcriptional remodeling required for adaption to iron starvation in this opportunistic fungal pathogen. HapX was found to be interconnected in a negative feed-back loop with the previously identified iron regulator SreA: SreA repressed expression of hapX during iron sufficiency and HapX repressed sreA during iron starvation. Genome-wide transcriptional profiling and analysis of selected metabolites (protophorphyrine IX, siderophores and amino acids) indicated extensive metabolic remodeling in response to iron starvation. HapX was found to participate in both, repression and activation of genes during iron starvation. HapX was in particular required for repression of iron-dependent and mitochondrial-localized activities including respiration, TCA cycle, amino acid metabolism, iron-sulfur-cluster biosynthesis and heme biosynthesis. Pathways positively affected by HapX included production of siderophores and the ribotoxin and major allergen AspF1. Analysis of the free amino acid pool revealed HapX-dependent coordination of the production of siderophores with the supply of its precursor ornithine. Consistent with the hapX expression pattern, HapX-deficiency was deleterious with respect to growth rate and conidiation during iron depleted but not iron-replete conditions. HapX-deficiency caused significant attenuation of virulence in a murine model aspergillosis underlining that A. fumigatus faces iron starvation in the host and that the HapX-dependent metabolic reprogramming is therefore crucial for virulence.
2010-07-01 | GSE22052 | GEO
Project description:Iron is an essential cofactor for a wide range of cellular processes. Previous studies have shown that siderophore-mediated uptake and intracellular handling of iron are crucial for virulence of Aspergillus fumigatus. Here we show that the bzip-type transcription factor HapX plays a crucial role in the transcriptional remodeling required for adaption to iron starvation in this opportunistic fungal pathogen. HapX was found to be interconnected in a negative feed-back loop with the previously identified iron regulator SreA: SreA repressed expression of hapX during iron sufficiency and HapX repressed sreA during iron starvation. Genome-wide transcriptional profiling and analysis of selected metabolites (protophorphyrine IX, siderophores and amino acids) indicated extensive metabolic remodeling in response to iron starvation. HapX was found to participate in both, repression and activation of genes during iron starvation. HapX was in particular required for repression of iron-dependent and mitochondrial-localized activities including respiration, TCA cycle, amino acid metabolism, iron-sulfur-cluster biosynthesis and heme biosynthesis. Pathways positively affected by HapX included production of siderophores and the ribotoxin and major allergen AspF1. Analysis of the free amino acid pool revealed HapX-dependent coordination of the production of siderophores with the supply of its precursor ornithine. Consistent with the hapX expression pattern, HapX-deficiency was deleterious with respect to growth rate and conidiation during iron depleted but not iron-replete conditions. HapX-deficiency caused significant attenuation of virulence in a murine model aspergillosis underlining that A. fumigatus faces iron starvation in the host and that the HapX-dependent metabolic reprogramming is therefore crucial for virulence. A. fumigatus 293 and hapX mutants were grown in the presence and absence of iron and in cultures shifted from no iron to iron-containing conditions after 1 h incubation. Hybridizations were performed with biological replicates for wt vs hapX +/- iron. For the iron-shift experiments, there were biological replicates for wt in both conditions and for hapX in -iron but there was only a single biological sample for hapX iron-shift sample. All hybs were performed with flip-dye pairs.
2010-07-01 | E-GEOD-22052 | biostudies-arrayexpress
Project description:The airborne fungus Aspergillus fumigatus causes opportunistic infections in humans with high mortality rates in immunocompromised patients. Previous work established that the bZIP transcription factor HapX is essential for virulence via adaptation to iron limitation by repressing iron-consuming pathways and activating iron acquisition mechanisms, such as the high-affinity siderophore-assisted iron uptake system. Moreover, HapX was shown to be essential for transcriptional activation of vacuolar iron storage and iron-dependent pathways in response to iron availability. Here, we demonstrate that HapX has a very short half-life during iron starvation, which is further decreased in response to iron, while siderophore biosynthetic enzymes are very stable. Immunoprecipitation experiments followed by LC-MS/MS analysis identified Fbx22 and SumO as HapX interactors and, in agreement, HapX post-translational modifications including ubiquitination of lysine161, sumoylation of lysine242 and phosphorylation of threonine319. All three modifications were enriched in the immediate adaptation from iron-limiting to iron-replete conditions. Interfering with these post-translational modifications, either by point mutations or by inactivation, of Fbx22 or SumO, altered HapX degradation, heme biosynthesis and iron resistance to different extents. Consistent with the need to regulate HapX protein levels, overexpression of hapX caused significant growth defects under iron sufficiency. Taken together, our results indicate that post-translational regulation of HapX is important to control iron homeostasis in A. fumigatus.
2021-07-20 | PXD026889 | Pride
Project description:To sustain iron homeostasis, microorganisms have evolved fine-tuned mechanisms for uptake, storage and detoxification of the essential metal iron. In the human pathogen Aspergillus fumigatus, the fungal-specific bZIP-type transcription factor HapX coordinates adaption to both iron starvation and iron excess and is thereby crucial for virulence. Previous studies indicated that a HapX homodimer interacts with the CCAAT-binding complex (CBC) to cooperatively bind bipartite DNA motifs; however, the significance of the HapX and CBC interaction and the mode of HapX-DNA recognition had not been resolved. In this study, we characterized the genome-wide binding profiles of HapX using the chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq). Our ChIP-seq results, in combination with in vitro surface plasmon resonance analysis, phylogenetic comparison, and genetic analysis, revealed an astonishing plasticity of the CBC:HapX DNA-recognition mode.
2019-12-31 | GSE129969 | GEO
Project description:Iron restriction imposed by mammalian hosts during an infection is a common mechanism of defense to reduce or avoid the pathogen infection. Iron is essential for organism survival due to its involvement in several biological processes. Aspergillus fumigatus causes invasive aspergillosis (IA), a disease that typically manifests in immunocompromised patients. A. fumigatus has two high affinity mechanisms of iron acquisition during infection: reductive iron assimilation (RIA) and siderophore-mediated iron uptake. It has been shown that siderophore production is important for A. fumigatus virulence, differently to the reductive iron uptake system. A. fumigatus PpzA, the catalytic subunit of protein phosphatase Z (PPZ), has been recently identified as associated with iron assimilation. Transcriptomic and proteomic comparisons between ∆ppzA and wild-type strains under iron starvation showed that PpzA has a broad influence on genes involved in secondary metabolism. LC-MS under standard and iron starvation conditions confirmed that the ΔppzA mutant had reduced production of pyripyropene A (PPA), fumagillin, fumiquinazoline A, TAFC, and helvolic acid. The ΔppzA was shown to be avirulent in a neutropenic murine model of invasive pulmonary aspergillosis. PpzA plays an important role at the interface between iron starvation, regulation of SM production and pathogenicity in A. fumigatus.
2018-03-19 | GSE97495 | GEO
Project description:Glucose is a widely used carbon source in laboratory practice to culture Aspergillus fumigatus, however, glucose availability is often low in its “natural habitats” including the human body. We used a physiological–transcriptomical approach to reveal differences between A. fumigatus Af293 cultures incubated on glucose, glucose and peptone, peptone (carbon limitation), or without any carbon source (carbon starvation). Autolytic cell wall degradation was upregulated by both carbon starvation and limitation. The importance of autolytic cell wall degradation in adaptation to carbon stress was also highlighted by approximately 12.4% of the A. fumigatus genomes harbor duplication of genes involved in N-acetyl glucosamine utilization. Glucose withdrawal increased redox imbalance, altered both the transcription of antioxidative enzyme genes and oxidative stress tolerance, downregulated iron acquisition, but upregulated heme protein genes. Transcriptional activity of the Gliotoxin cluster was low in all experiments, while the Fumagillin cluster showed substantial activity both on glucose and under carbon starvation, and the Hexadehydro-astechrome cluster only on glucose. We concluded that glucose withdrawal substantially modified the physiology of A. fumigatus including processes that contribute to virulence. This may explain the challenge of predicting the in vivo behavior of A. fumigatus based on data from glucose rich cultures.
2022-12-09 | GSE216000 | GEO
Project description:Aspergillus fumigatus has to cope with a combination of several stress types in the human body, and the interplay between the different stress responses can significantly influence the survival of this human pathogen during the invasion of the host organism. In this study, we examined how the H2O2 induced oxidative stress response depends on iron availability. Surprisingly, the applied H2O2 treatment, which induced only a negligible stress response in iron fed cultures, deleteriously affected the fungus under iron starvation and the majority of observed transcriptome-level stress responses were characteristic only for the combined H2O2-iron starvation stress treatments. Our data suggest that the survival of the fungus highly depended on fragile balances, e.g. between siderophore and ergosterol productions or between economization on iron and production of essential iron containing proteins. The applied stress conditions also affected several processes related to virulence or drug susceptibility including secondary metabolism, zinc acquisition or antifungal drug transport. Our data clearly demonstrate that studying stress responses under single stress treatments is not sufficient at all to understand how fungal pathogens survive in a complex habitat and support the view that the evolutionary success of A. fumigatus as an opportunistic human pathogen is not the mere consequence of the productions of certain virulence factors. Importantly, this fungal pathogen is able to mount and coordinate high-complexity and outstandingly efficient responses to multiple and superpositioning stresses in various harsh habitats like the human body.
2018-01-01 | GSE94818 | GEO
Project description:To investigate the influence of Aspergillus fumigatus on iron regulation in macrophages, we obtained macrophages in culture from human derived monocytes and co-cultured the monocyte-derived macrophages with Aspergillus conidia at a 1:1 ratio. We collected samples at 0, 2, 4, 6 and 8 hours and extracted RNA. We then performed gene expression profiling analysis using data obtained from RNA-seq of control macrophages and macrophage co-cultured with Aspergillus fumigatus at five time points.
2022-05-08 | GSE202286 | GEO
Project description:Genomic DNA from five strains, Aspergillus fumigatus Af71, Aspergillus fumigatus Af294, Aspergillus clavatus, Neosartorya fenneliae, and Neosartorya fischeri, were co-hybridized with that of Aspergillus fumigatus Af293 and compared.
2005-05-15 | E-MEXP-333 | biostudies-arrayexpress
Project description:In patients with chronic pulmonary disease colonization with the mold Aspergillus fumigatus is associated with declining pulmonary function and obstructive airway disease. One potential effector of this inflammatory response is the pulmonary mast cell. In vitro studies have demonstrated that A. fumigatus contact induces IgE-independent mast cell degranulation. Conversely, the Aspergillus secondary metabolite gliotoxin has been shown to suppress mast cell activation. These contradictory results emphasize the need for a better understanding of the interactions between A. fumigatus and mast cells. Thus, the objective of this work was to identify A. fumigatus genes that are differentially regulated upon exposure to mast cells. Transcriptional profiling experiments indicated that, in addition to genes encoding for iron acquisition systems, allergens and putative virulence factors, genes from the gliotoxin biosynthesis cluster were significantly down-regulated upon exposure to mast cells. Globally, the results from this study provide insight into the A. fumigatus response to mast cells and suggest that one mechanism by which the host may circumvent the effects of gliotoxin is via the suppression of fungal gliotoxin synthesis by mast cells.
2012-03-02 | GSE27610 | GEO