Ontology highlight
ABSTRACT:
PROVIDER: PRJNA1076841 | ENA |
REPOSITORIES: ENA
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Project description:The opportunistic pathogen Cryptococcus neoformans causes fungal meningoencephalitis in immunocompromised individuals. In previous studies, we found that the Hap complex in this pathogen represses genes encoding mitochondrial respiratory functions and TCA cycle components under low-iron conditions. The orthologous Hap2/3/4/5 complex in Saccharomyces cerevisiae exerts a regulatory influence on mitochondrial functions and Hap4 is subject to glucose repression via the carbon catabolite repressor Mig1. In this study, we explored the regulatory link between a candidate ortholog of the Mig1 protein and the HapX component of the Hap complex in C. neoformans. This analysis revealed repression of MIG1 by HapX and activation of HAPX by Mig1 in low iron conditions, and Mig1 regulation of mitochondrial functions including respiration, tolerance for reactive oxygen species, and expression of genes for iron-consuming and iron-acquisition functions. Consistent with these regulatory functions, a mig1Î mutant had impaired growth on inhibitors of mitochondrial respiration and ROS inducers. Furthermore, deletion of MIG1 provoked a dysregulation in nutrient sensing via the TOR pathway and impacted the pathway for cell wall remodeling. Importantly, loss of Mig1 increased susceptibility to fluconazole thus further establishing a link between azole antifungal drugs and mitochondrial function. Mig1 and HapX were also required together for survival in macrophages, but Mig1 alone had a minimal impact on virulence in mice. Overall, these studies provide novel insights into a HapX/Mig1 regulatory network and reinforce an association between mitochondrial dysfunction and drug susceptibility that may provide new targets for the development of antifungal drugs. In this study, transcription profiles of WT and mig1D mutant strains of Cryptococcus neoformans were compared in a dye-swap experiment following 6hr exposure to Low Iron Medium (LIM) or LIM + 100mM FeCl3.
2015-12-17 | E-GEOD-76063 | biostudies-arrayexpress
Project description:Cryptococcus neoformans is a human fungal pathogen responsible for fatal infections, especially in patients with a depressed immune system. Overexposure to antifungal drugs due to prolonged treatment regimens and structure-similar applications in agriculture have weakened the efficacy of current antifungals in the clinic. The rapid evolution of antifungal resistance urges the discovery of new compounds that inhibit fungal virulence factors, rather than directly killing the pathogen as alternative strategies to overcome disease and reduce selective pressure towards resistance. Recent studies, including our own, have highlighted the antimicrobial properties of natural sources, such as invertebrates, against human fungal pathogens, including C. neoformans, through virulence factor impairment. Here, we evaluated the efficacy of freshwater mussel extracts (crude and clarified) against virulence factor production (i.e., thermotolerance, melanin, capsule, and biofilm) in C. neoformans. Similarly, we demonstrated the critical potential of these extracts to increase the susceptibility of the pathogen to fluconazole across resistant strains, overcoming a globally devastating problem. Additionally, we measured the inhibitory activity of the extracts against peptidases related to fungal virulence and drug resistance. Furthermore, we integrated these phenotypic findings with quantitative proteomics profiling to define distinct signatures of each treatment and validated a new mechanism of anti-virulence action for a selected extract. By understanding the mechanisms driving the antifungal activity of mussels, we may develop innovative treatments for fungal infections lacking susceptibility to conventional drugs.
2024-01-27 | PXD043643 | Pride
Project description:Sampangine, a plant-derived alkaloid found in the Annonaceae family, exhibits strong inhibitory activity against the opportunistic fungal pathogens Candida albicans, Cryptococcus neoformans and Aspergillus fumigatus. In the present study, transcriptional profiling experiments coupled with the analysis of mutants were performed in an effort to elucidate its mechanism of action. Using Saccharomyces cerevisiae as a model organism, we show that sampangine produces a transcriptional response indicative of hypoxia, altering the expression of genes known to respond to low oxygen conditions. Several additional lines of evidence obtained suggest that these responses could involve effects on heme. First, the hem1 deletion mutant lacking the first enzyme in the heme biosynthetic pathway showed increased sensitivity to sampangine, and exogenously supplied hemin partially rescued the inhibitory activity of sampangine in wild-type cells. In addition, heterozygous mutants with deletions in genes involved in five out of eight steps in the heme biosynthetic pathway showed increased susceptibility to sampangine. Furthermore, spectral analysis of pyridine extracts indicated significant accumulation of free porphyrins in sampangine-treated cells. Transcriptional profiling experiments were also performed in C. albicans to investigate the response of a pathogenic fungal species to sampangine. Taking into account the known differences in the physiological responses of C. albicans and S. cerevisiae to low oxygen, significant correlations were observed between the two transcription profiles suggestive of heme-related defects. Our results indicate that the antifungal activity of the plant alkaloid sampangine is due, at least in part, to perturbations in the biosynthesis or metabolism of heme. GSE10073: Gene expression response to the antifungal compound sampangine in S. cerevisiae GSE10075: Gene expression response to the antifungal compound sampangine in C. albicans Keywords: SuperSeries Refer to individual Series
2010-05-26 | E-GEOD-10104 | biostudies-arrayexpress
Project description:Species within the human pathogenic Cryptococcus species complex are major threats to public health, causing about one million infections globally each year. Cryptococcus amylolentus is the most closely known related species of the pathogenic Cryptococcus species complex, and it is non-pathogenic. Additionally, while pathogenic Cryptococcus species have bipolar mating systems with a single large MAT locus that represents a derived state in Basidiomycetes, C. amylolentus has a tetrapolar mating system with two MAT loci (P/R and HD) located on different chromosomes. Thus, studying C. amylolentus will shed light on the origin and evolution of pathogenesis, as well as the transition from tetrapolar to bipolar mating systems in the pathogenic Cryptococcus species. In this study, we sequenced, assembled, and annotated the genomes of two C. amylolentus isolates, CBS6039 and CBS6273, which are sexual and interfertile. Genome comparison between the two C. amylolentus isolates identified the boundaries and the complete gene contents of the P/R and HD MAT loci. Also, bioinformatics and ChIP-seq analyses showed that C. amylolentus has regional centromeres that are enriched with species-specific transposable and repetitive elements, similar to the centromeric structures in the pathogenic Cryptococcus species. Additionally, we found that while neither of the P/R and HD loci in C. amylolentus is physically linked to its centromere, both MAT loci exhibit centromere linkage in meiosis, suggesting the presence of recombinational suppressors and/or epistatic gene interactions in the inter MAT-CEN regions. Furthermore, genomic comparison between C. amylolentus and pathogenic Cryptococcus species provides evidence that chromosomal rearrangements mediated by intercentromeric recombination have occurred after the two lineages split from their common ancestor. We propose a model in which the evolution of the bipolar mating system was initiated by an ectopic recombination event mediated by repetitive elements located within the centromeric regions and shared between chromosomes. This translocation brought the P/R and HD loci onto the same chromosome, and was followed by chromosomal rearrangements that resulted in the two MAT loci becoming physically linked and eventually fused to form the single contiguous MAT locus that is now extant in the pathogenic Cryptococcus species.
2018-04-08 | GSE95128 | GEO
Project description:Invasive fungal infections (IFIs) are difficult to treat. Few effective antifungal drugs are available and many have problems with toxicity, efficacy and drug-resistance. To overcome these challenges, existing therapies may be enhanced using more than one agent acting in synergy. Previously, we have found amphotericin B (AMB) and the iron chelator, lactoferrin (LF), were synergistic against Cryptococcus neoformans and Saccharomyces cerevisiae. This study investigates the mechanism of AMB+LF synergy using RNA-seq in Cryptococcus neoformans H99.
2019-09-08 | GSE130375 | GEO
Project description:The opportunistic pathogen Cryptococcus neoformans causes fungal meningoencephalitis in immunocompromised individuals. In previous studies, we found that the Hap complex in this pathogen represses genes encoding mitochondrial respiratory functions and TCA cycle components under low-iron conditions. The orthologous Hap2/3/4/5 complex in Saccharomyces cerevisiae exerts a regulatory influence on mitochondrial functions and Hap4 is subject to glucose repression via the carbon catabolite repressor Mig1. In this study, we explored the regulatory link between a candidate ortholog of the Mig1 protein and the HapX component of the Hap complex in C. neoformans. This analysis revealed repression of MIG1 by HapX and activation of HAPX by Mig1 in low iron conditions, and Mig1 regulation of mitochondrial functions including respiration, tolerance for reactive oxygen species, and expression of genes for iron-consuming and iron-acquisition functions. Consistent with these regulatory functions, a mig1Δ mutant had impaired growth on inhibitors of mitochondrial respiration and ROS inducers. Furthermore, deletion of MIG1 provoked a dysregulation in nutrient sensing via the TOR pathway and impacted the pathway for cell wall remodeling. Importantly, loss of Mig1 increased susceptibility to fluconazole thus further establishing a link between azole antifungal drugs and mitochondrial function. Mig1 and HapX were also required together for survival in macrophages, but Mig1 alone had a minimal impact on virulence in mice. Overall, these studies provide novel insights into a HapX/Mig1 regulatory network and reinforce an association between mitochondrial dysfunction and drug susceptibility that may provide new targets for the development of antifungal drugs.
2015-12-17 | GSE76063 | GEO
Project description:Fusarium spp. are fungal pathogens of humans and plants. Fusarium oxysporum and Fusarium solani are important species isolated from infections such as onychomycosis, fungal keratitis, invasive infections, and disseminated diseases. These pathologies have a very difficult therapeutic management and poor therapeutic responses, especially in patients with disseminated infection. Little information is available regarding the molecular mechanisms responsible for antifungal resistance in these fungi. methods: In this study, we performed a quantitative analysis of the transcriptional profile of F. oxysporum and F. solani, challenged with amphotericin B (AMB) and posaconazole (PSC) using RNA-seq. Quantitative real-time reverse transcription PCR (qRT-PCR) was used to validate the results results: Several genes related to mechanisms of antifungal resistance such as efflux pumps, ergosterol pathway synthesis, and responses to oxidative stress were found. Genes such as ERG11, ERG5, the Major Facilitator Superfamily (MFS), thioredoxin, and different dehydrogenase genes may explain the reduced susceptibility of Fusarium spp. against azoles and the possible mechanisms that may play an important role in induced resistance against polyenes. conclusions: Important differences in the levels of transcriptional expression were found between F. oxysporum and F. solani exposed to the two different antifungal treatments. Knowledge on the gene expression profiles and gene regulatory networks in Fusarium spp. during exposure to antifungal compounds, may help to identify possible molecular targets for the development of novel, better, and more specific therapeutic compounds. profile transcriptional of Fusarium spp changed to antifungal treatments in vitro
2016-06-01 | E-GEOD-82060 | biostudies-arrayexpress
Project description:Candida auris has emerged as a problematic fungal pathogen associated with high morbidity and mortality. Amphotericin B (AmB) is the most effective antifungal used to treat invasive fungal candidiasis, with resistance rarely observed among clinical isolates. However, C. auris possesses extraordinary resistant profiles against all available antifungal drugs, including AmB. In our pursuit of potential solutions, we conducted a screening of a panel of 727 FDA-approved drugs and identified the proton pump inhibitor lansoprazole (LNP) as a potent enhancer of AmB’s activity against C. auris. LNP also potentiates the antifungal activity of AmB against other medically important species of Candida and Cryptococcus. Our investigations into the mechanism of action unveiled that LNP metabolite(s) interact with a crucial target in the mitochondrial respiratory chain (complex III, known as cytochrome bc1). This interaction increases oxidative stress within fungal cells. Our results demonstrated the critical role of an active respiratory function in the antifungal activity of LNP. Most importantly, LNP restored the efficacy of AmB in an immunocompromised mouse model, resulting in a 1.7-log (~98%) CFU reduction in the burden of C. auris in the kidneys. Our findings strongly advocate for a thorough and comprehensive evaluation of LNP as a cytochrome bc1 inhibitor for combating drug-resistant C. auris infections.
2024-03-13 | GSE244094 | GEO
Project description:Lysine acetylation and ubiquitination are one of many protein modifications and play a crucial role in the biological regulation of many organisms, but little is known about the relationship between acetylation and ubiquitination few. Here, the Isw1 protein is an important member of the chromatin remodeling complex, and we performed single-protein modification mass spectrometry detection of the C. neoformans Isw1 protein and site mutations for both detected modifications. The data showed that the two modifications of Cryptococcus neoformans Isw1 protein have a balance of each other. Acetylation can maintain protein stability and maintain protein function, while ubiquitination can reduce protein level and maintain Isw1 protein expression. The expression level of Isw1 protein leads to resistance to antifungal drugs. These results reveal the resistance mechanism of Isw1 protein of Cryptococcus neoformans to antifungal drugs.
2022-12-26 | PXD037150 | Pride
Project description:A family of APSES transcription factor is known to be fungal-specific transcriptional regulators and play important roles in governing growth, differentiation, and virulence of diverse fungal pathogens. Yet none of APSES-like transcription factors have been identified and investigated in a basidiomycetous fungal pathogen, Cryptococcus neoformans. In the present study we discovered an APSES-like transcription factor, mbs1 (Mbp1/Swi4-like APSES protein 1), as one of novel flucytosine-responsive genes (total 194 genes) identified through comparative transcriptome analysis of C. neoformans hybrid sensor kinase mutants, tco1 and tco2 mutants, which displayed differential flucytosine-susceptibility. Supporting the microarray data, Northern blot and quantitative RT-PCR analysis confirmed that expression of mbs1 is rapidly induced in response to flucytosine in the wild-type strain, but not in the tco1 and tco2 mutants. Furthermore, C. neoformans with deletion of the mbs1 gene exhibited increased susceptibility to flucytosine. Intriguingly, mbs1 plays pleiotropic roles in diverse cellular process of C. neoformans. mbs1 positively regulates ergosterol biosynthesis and thereby its inhibition confers increased susceptibility and resistance to amphotericin B and azole drugs, respectively. mbs1 is also involved in DNA damage repair counteracting genotoxic stresses. During sexual differentiation mbs1 represses pheromone production, but promotes cell-cell fusion. Furthermore mbs1 is required for production of antioxidant melanin pigment and full virulence of C. neoformans. Finally we also performed DNA microarrray analysis to identify mbs1-regulated genes in C. neoformans. A majority of them were found to be involved in cell cycle regulation and DNA repair. Therefore, this study provides a novel antifungal therapeutic method for treatment of cryptococcosis. total RNAs are extracted 2 strains from H99 (H99 Wild type strain (Cryptococcus neoformans var. grubii serotype A), mbs1Δ), We use the mixed all of total RNAs from this experiment as a control RNA. We use Cy5 as Sample dye and Cy3 as a control dye.
2011-06-23 | E-GEOD-30156 | biostudies-arrayexpress