175 research outputs found

    The impact of the Fungus-Host-Microbiota interplay upon Candida albicans infections : current knowledge and new perspectives

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    ACKNOWLEDGEMENTS: We thank our friends and colleagues in the medical mycology, fungal immunology and microbiota fields for many thought-provoking discussions. FUNDING: We received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie action, Innovative Training Network: FunHoMic; grant N° 812969. CdE received funding from the French Government ‘Investissement d’Avenir’ program (Laboratoire d’Excellence Integrative Biology of Emerging Infectious Diseases, ANR-10-LABX-62-IBEID), the Agence Nationale de la Recherche (ERA-Net Infect-ERA, FUNCOMPATH, ANR-14-IFEC-0004), the EU Horizon2020 consortium “Host-Directed Medicine in invasive FUNgal infections” - HDM-FUN (Grant Agreement 847507). SLL and CdE received funding from the Swiss National Science Foundation (Sinergia program, #CRSII5_173863). BIOASTER received funding from the French Government ‘Investissement d’Avenir’ program (Grant No. ANR-10-AIRT-03). MSG was supported by a Humboldt Research Fellowship for Postdoctoral Researchers by the Alexander von Humboldt-Foundation and the Deutsche Forschungsgemeinschaft (DFG) Emmy Noether Program (project no. 434385622 / GR 5617/1-1). BH was supported by the Deutsche Forschungsgemeinschaft (DFG) project Hu 532/20-1, project C1 within the Collaborative Research Centre (CRC)/Transregio 124 FungiNet and the Balance of the Microverse Cluster under Germany´s Excellence Strategy – EXC 2051 – Project-ID 390713860, the EU Horizon2020 consortium “Host-Directed Medicine in invasive FUNgal infections” - HDM-FUN (Grant Agreement 847507), the Leibniz Association Campus InfectoOptics SAS-2015-HKI-LWC and the Wellcome Trust (215599/Z/19/Z). IDJ was supported by the Deutsche orschungsgemeinschaft (DFG) project C5 within the Collaborative Research Centre (CRC)/Transregio 124 FungiNet and the Balance of the Microverse Cluster under Germany´s Excellence Strategy – EXC 2051 – Project-ID 390713860, the Leibniz Association Campus InfectoOptics SAS-2015-HKI-LWC and the Wellcome Trust (Grant 215599/Z/19/Z). CM received funding from the the Instituto de Salud Carlos III/FEDER. MGN was supported by an ERC Advanced Grant (#833247) and a Spinoza grant of the Netherlands Organization for Scientific Research. CAM was supported by EU Horizon2020 consortium “Host-Directed Medicine in invasive FUNgal infections” -HDM-FUN (Grant Agreement 847507) and the Wellcome Trust Strategic Award for Medical Mycology and Fungal Immunology (097377/Z/11/Z). AWW receives core funding support from the Scottish Government’s Rural and Environment Science and Analytical Services (RESAS). AJPB was supported by a programme grant from the UK Medical Research Council (MR/M026663/1) and by the Medical Research Council Centre for Medical Mycology at the University of Exeter (MR/N006364/1).Peer reviewedPublisher PD

    Mutations in the Catalytic Loop HRD Motif Alter the Activity and Function of Drosophila Src64

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    The catalytic loop HRD motif is found in most protein kinases and these amino acids are predicted to perform functions in catalysis, transition to, and stabilization of the active conformation of the kinase domain. We have identified mutations in a Drosophila src gene, src64, that alter the three HRD amino acids. We have analyzed the mutants for both biochemical activity and biological function during development. Mutation of the aspartate to asparagine eliminates biological function in cytoskeletal processes and severely reduces fertility, supporting the amino acid's critical role in enzymatic activity. The arginine to cysteine mutation has little to no effect on kinase activity or cytoskeletal reorganization, suggesting that the HRD arginine may not be critical for coordinating phosphotyrosine in the active conformation. The histidine to leucine mutant retains some kinase activity and biological function, suggesting that this amino acid may have a biochemical function in the active kinase that is independent of its side chain hydrogen bonding interactions in the active site. We also describe the phenotypic effects of other mutations in the SH2 and tyrosine kinase domains of src64, and we compare them to the phenotypic effects of the src64 null allele

    “PMA Sounds Fun”: Negotiating Drug Discourses Online

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    In 2007, a young woman, Annabel Catt, died after consuming a capsule sold as “ecstasy” that contained para-methoxyamphetamine. In this paper, we describe how this death was depicted in online drug-user communities and illustrate how the meanings of drug use are negotiated in online settings. News articles, public online discussions, and online fieldwork formed the data. This paper demonstrates how dominant drug discourses may be resisted by drug users, drawing on theories of health resistance and Kane Race’s concept of counter public health. Online environments may offer ways of engaging people who use drugs that acknowledge both pleasure and safety. The study’s limitations are noted

    Analysis of the Aspergillus fumigatus Proteome Reveals Metabolic Changes and the Activation of the Pseurotin A Biosynthesis Gene Cluster in Response to Hypoxia

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    The mold Aspergillus fumigatus is the most important airborne fungal pathogen. Adaptation to hypoxia represents an important virulence attribute for A. fumigatus. Therefore, we aimed at obtaining a comprehensive overview about this process on the proteome level. To ensure highly reproducible growth conditions, an oxygen-controlled, glucose-limited chemostat cultivation was established. Two-dimensional gel electrophoresis analysis of mycelial and mitochondrial proteins as well as two-dimensional Blue Native/SDS-gel separation of mitochondrial membrane proteins led to the identification of 117 proteins with an altered abundance under hypoxic in comparison to normoxic conditions. Hypoxia induced an increased activity of glycolysis, the TCA-cycle, respiration, and amino acid metabolism. Consistently, the cellular contents in heme, iron, copper, and zinc increased. Furthermore, hypoxia induced biosynthesis of the secondary metabolite pseurotin A as demonstrated at proteomic, transcriptional, and metabolite levels. The observed and so far not reported stimulation of the biosynthesis of a secondary metabolite by oxygen depletion may also affect the survival of A. fumigatus in hypoxic niches of the human host. Among the proteins so far not implicated in hypoxia adaptation, an NO-detoxifying flavohemoprotein was one of the most highly up-regulated proteins which indicates a link between hypoxia and the generation of nitrosative stress in A. fumigatus

    Association between TCF7L2 gene polymorphisms and susceptibility to Type 2 Diabetes Mellitus: a large Human Genome Epidemiology (HuGE) review and meta-analysis

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    <p>Abstract</p> <p>Background</p> <p>Transcription factor 7-like 2 (<it>TCF7L2</it>) has been shown to be associated with type 2 diabetes mellitus (T2MD) in multiple ethnic groups in the past two years, but, contradictory results were reported for Chinese and Pima Indian populations. The authors then performed a large meta-analysis of 36 studies examining the association of type 2 diabetes mellitus (T2DM) with polymorphisms in the <it>TCF7L2 </it>gene in various ethnicities, containing rs7903146 C-to-T (IVS3C>T), rs7901695 T-to-C (IVS3T>C), a rs12255372 G-to-T (IVS4G>T), and rs11196205 G-to-C (IVS4G>C) polymorphisms and to evaluate the size of gene effect and the possible genetic mode of action.</p> <p>Methods</p> <p>Literature-based searching was conducted to collect data and three methods, that is, fixed-effects, random-effects and Bayesian multivariate mete-analysis, were performed to pool the odds ratio (<it>OR</it>). Publication bias and study-between heterogeneity were also examined.</p> <p>Results</p> <p>The studies included 35,843 cases of T2DM and 39,123 controls, using mainly primary data. For T2DM and IVS3C>T polymorphism, the Bayesian <it>OR </it>for TT homozygotes and TC heterozygotes versus CC homozygote was 1.968 (95% credible interval (<it>CrI</it>): 1.790, 2.157), 1.406 (95% <it>CrI</it>: 1.341, 1.476), respectively, and the population attributable risk (PAR) for the TT/TC genotypes of this variant is 16.9% for overall. For T2DM and IVS4G>T polymorphism, TT homozygotes and TG heterozygotes versus GG homozygote was 1.885 (95%<it>CrI</it>: 1.698, 2.088), 1.360 (95% <it>CrI</it>: 1.291, 1.433), respectively. Four <it>OR</it>s among these two polymorphisms all yielded significant between-study heterogeneity (P < 0.05) and the main source of heterogeneity was ethnic differences. Data also showed significant associations between T2DM and the other two polymorphisms, but with low heterogeneity (<it>P </it>> 0.10). Pooled <it>OR</it>s fit a codominant, multiplicative genetic model for all the four polymorphisms of <it>TCF7L2 </it>gene, and this model was also confirmed in different ethnic populations when stratification of IVS3C>T and IVS4G>T polymorphisms except for Africans, where a dominant, additive genetic mode is suggested for IVS3C>T polymorphism.</p> <p>Conclusion</p> <p>This meta-analysis demonstrates that four variants of <it>TCF7L2 </it>gene are all associated with T2DM, and indicates a multiplicative genetic model for all the four polymorphisms, as well as suggests the <it>TCF7L2 </it>gene involved in near 1/5 of all T2MD. Potential gene-gene and gene-environmental interactions by which common variants in the <it>TCF7L2 </it>gene influence the risk of T2MD need further exploration.</p

    In vivo Hypoxia and a Fungal Alcohol Dehydrogenase Influence the Pathogenesis of Invasive Pulmonary Aspergillosis

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    Currently, our knowledge of how pathogenic fungi grow in mammalian host environments is limited. Using a chemotherapeutic murine model of invasive pulmonary aspergillosis (IPA) and 1H-NMR metabolomics, we detected ethanol in the lungs of mice infected with Aspergillus fumigatus. This result suggests that A. fumigatus is exposed to oxygen depleted microenvironments during infection. To test this hypothesis, we utilized a chemical hypoxia detection agent, pimonidazole hydrochloride, in three immunologically distinct murine models of IPA (chemotherapeutic, X-CGD, and corticosteroid). In all three IPA murine models, hypoxia was observed during the course of infection. We next tested the hypothesis that production of ethanol in vivo by the fungus is involved in hypoxia adaptation and fungal pathogenesis. Ethanol deficient A. fumigatus strains showed no growth defects in hypoxia and were able to cause wild type levels of mortality in all 3 murine models. However, lung immunohistopathology and flow cytometry analyses revealed an increase in the inflammatory response in mice infected with an alcohol dehydrogenase null mutant strain that corresponded with a reduction in fungal burden. Consequently, in this study we present the first in vivo observations that hypoxic microenvironments occur during a pulmonary invasive fungal infection and observe that a fungal alcohol dehydrogenase influences fungal pathogenesis in the lung. Thus, environmental conditions encountered by invading pathogenic fungi may result in substantial fungal metabolism changes that influence subsequent host immune responses

    Cancer Genomics Identifies Regulatory Gene Networks Associated with the Transition from Dysplasia to Advanced Lung Adenocarcinomas Induced by c-Raf-1

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    Background: Lung cancer is a leading cause of cancer morbidity. To improve an understanding of molecular causes of disease a transgenic mouse model was investigated where targeted expression of the serine threonine kinase c-Raf to respiratory epithelium induced initialy dysplasia and subsequently adenocarcinomas. This enables dissection of genetic events associated with precancerous and cancerous lesions. Methodology/Principal Findings: By laser microdissection cancer cell populations were harvested and subjected to whole genome expression analyses. Overall 473 and 541 genes were significantly regulated, when cancer versus transgenic and non-transgenic cells were compared, giving rise to three distinct and one common regulatory gene network. At advanced stages of tumor growth predominately repression of gene expression was observed, but genes previously shown to be upregulated in dysplasia were also up-regulated in solid tumors. Regulation of developmental programs as well as epithelial mesenchymal and mesenchymal endothelial transition was a hall mark of adenocarcinomas. Additionaly, genes coding for cell adhesion, i.e. the integrins and the tight and gap junction proteins were repressed, whereas ligands for receptor tyrosine kinase such as epi- and amphiregulin were up-regulated. Notably, Vegfr- 2 and its ligand Vegfd, as well as Notch and Wnt signalling cascades were regulated as were glycosylases that influence cellular recognition. Other regulated signalling molecules included guanine exchange factors that play a role in an activation of the MAP kinases while several tumor suppressors i.e. Mcc, Hey1, Fat3, Armcx1 and Reck were significantly repressed. Finally, probable molecular switches forcing dysplastic cells into malignantly transformed cells could be identified. Conclusions/Significance: This study provides insight into molecular pertubations allowing dysplasia to progress further to adenocarcinoma induced by exaggerted c-Raf kinase activity
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