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FungiNet A - Aspergillus projects

Overview
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Programme: Collaborative Research Center / Transregio 124 "Pathogenic fungi and their human host: Networks of Interaction - FungiNet"

SEEK ID: https://funginet.hki-jena.de/projects/15

Public web page: http://www.funginet.de/project-area-a.html

Organisms: Aspergillus fumigatus

INF PALs: No PALs for this Project

Project created: 1st Oct 2012

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DMykG 2015 Programmheft
FungiNet total, FungiNet A - Aspergillus projects, FungiNet B - Bioinformatics projects, FungiNet C - Candida projects, INF, Z2
No description specified

Creator: Reinhard Guthke

Contributor: Reinhard Guthke

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DMykG_2015 Programmheft
FungiNet total, FungiNet A - Aspergillus projects, FungiNet B - Bioinformatics projects, FungiNet C - Candida projects, INF, Z2
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Creator: Reinhard Guthke

Contributor: Reinhard Guthke

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N-Heterocyclization in Gliotoxin Biosynthesis is Catalyzed by a Distinct Cytochrome P450 Monooxygenase.
FungiNet A - Aspergillus projects

Abstract (Expand)

Gliotoxin and related epidithiodiketopiperazines (ETP) from diverse fungi feature highly functionalized hydroindole scaffolds with an array of medicinally and ecologically relevant activities. Mutation … analysis, heterologous reconstitution, and biotransformation experiments revealed that a cytochrome P450 monooxygenase (GliF) from the human-pathogenic fungus Aspergillus fumigatus plays a key role in the formation of the complex heterocycle. In vitro assays using a biosynthetic precursor from a blocked mutant showed that GliF is specific to ETPs and catalyzes an unprecedented heterocyclization reaction that cannot be emulated with current synthetic methods. In silico analyses indicate that this rare biotransformation takes place in related ETP biosynthetic pathways.

Authors: D. H. Scharf, P. Chankhamjon, K. Scherlach, J. Dworschak, T. Heinekamp, M. Roth, A. A. Brakhage, C. Hertweck

Date Published: 15th Jan 2021

Journal: Chembiochem

Flotillin-Dependent Membrane Microdomains Are Required for Functional Phagolysosomes against Fungal Infections.
FungiNet A - Aspergillus projects, B4

Abstract (Expand)

Lipid rafts form signaling platforms on biological membranes with incompletely characterized role in immune response to infection. Here we report that lipid-raft microdomains are essential components … of phagolysosomal membranes of macrophages and depend on flotillins. Genetic deletion of flotillins demonstrates that the assembly of both major defense complexes vATPase and NADPH oxidase requires membrane microdomains. Furthermore, we describe a virulence mechanism leading to dysregulation of membrane microdomains by melanized wild-type conidia of the important human-pathogenic fungus Aspergillus fumigatus resulting in reduced phagolysosomal acidification. We show that phagolysosomes with ingested melanized conidia contain a reduced amount of free Ca(2+) ions and that inhibition of Ca(2+)-dependent calmodulin activity led to reduced lipid-raft formation. We identify a single-nucleotide polymorphism in the human FLOT1 gene resulting in heightened susceptibility for invasive aspergillosis in hematopoietic stem cell transplant recipients. Collectively, flotillin-dependent microdomains on the phagolysosomal membrane play an essential role in protective antifungal immunity.

Authors: F. Schmidt, A. Thywissen, M. Goldmann, C. Cunha, Z. Cseresnyes, H. Schmidt, M. Rafiq, S. Galiani, M. H. Graler, G. Chamilos, J. F. Lacerda, A. Jr Campos, C. Eggeling, Marc Thilo Figge, Thorsten Heinekamp, S. G. Filler, A. Carvalho, Axel Brakhage

Date Published: 18th Aug 2020

Journal: Cell Rep

Quantitative Impact of Cell Membrane Fluorescence Labeling on Phagocytosis Measurements in Confrontation Assays.
FungiNet A - Aspergillus projects, B4

Abstract (Expand)

Phagocytosis is series of steps where the pathogens and the immune cells interact during an invasion. This starts with the adhesion process between the host and pathogen cells, and is followed by the … engulfment of the pathogens. Many analytical methods that are applied to characterize phagocytosis based on imaging the host-pathogen confrontation assays rely on the fluorescence labeling of cells. However, the potential effect of the membrane labeling on the quantitative results of the confrontation assays has not been studied in detail. In this study, we determine whether the fluorescence labeling processes themselves influence the results of the phagocytosis measurements. Here, alveolar macrophages, which form one of the most important compartments of the innate immune system, were used as an example of host cells, whereas Aspergillus fumigatus and Lichtheimia corymbifera that cause aspergillosis and mucormycosis, respectively, were studied as examples for pathogens. At first, our study investigated the importance of the sequence of steps of the fixation process when preparing the confrontation assay sample for microscopy studies. Here we showed that applying the fixation agent before the counter-staining causes miscalculations during the determination of the phagocytic measures. Furthermore, we also found that staining the macrophages with various concentrations of DID, as a typical membrane label, in most cases altered the capability of macrophages to phagocytose FITC-stained A. fumigatus and L. corymbifera spores in comparison with unlabeled macrophages. This effect of the DID staining showed a differential character dependent upon the labeling status and the specific type of pathogen. Moreover, labeling the spores of A. fumigatus and L. corymbifera with FITC increased the phagocytic measures during confrontation with unlabeled macrophages when compared to label-free spores. Overall, our study confirms that the staining process itself may significantly manipulate the quantitative outcome of the confrontation assay. As a result of our study, we also developed a user-friendly image analysis tool that analyses confrontation assays both with and without fluorescence labeling of the host cells and of the pathogens. Our image analysis algorithm saves experimental work effort and time, provides more precise results when calculating the phagocytic measures, and delivers a convenient analysis tool for the biologists to monitor host-pathogen interactions as they happen without the artifacts that fluorescence labeling imposes on biological interactions.

Authors: Z. Cseresnyes, M. I. A. Hassan, H. M. Dahse, Kerstin Voigt, Marc Thilo Figge

Date Published: 26th Jun 2020

Journal: Front Microbiol

Enolase From Aspergillus fumigatus Is a Moonlighting Protein That Binds the Human Plasma Complement Proteins Factor H, FHL-1, C4BP, and Plasminogen.
FungiNet A - Aspergillus projects, FungiNet C - Candida projects, B4

Abstract (Expand)

The opportunistic fungal pathogen Aspergillus fumigatus can cause severe infections, particularly in immunocompromised individuals. Upon infection, A. fumigatus faces the powerful and directly acting … immune defense of the human host. The mechanisms on how A. fumigatus evades innate immune attack and complement are still poorly understood. Here, we identify A. fumigatus enolase, AfEno1, which was also characterized as fungal allergen, as a surface ligand for human plasma complement regulators. AfEno1 binds factor H, factor-H-like protein 1 (FHL-1), C4b binding protein (C4BP), and plasminogen. Factor H attaches to AfEno1 via two regions, via short conserved repeats (SCRs) 6-7 and 19-20, and FHL-1 contacts AfEno1 via SCRs 6-7. Both regulators when bound to AfEno1 retain cofactor activity and assist in C3b inactivation. Similarly, the classical pathway regulator C4BP binds to AfEno1 and bound to AfEno1; C4BP assists in C4b inactivation. Plasminogen which binds to AfEno1 via lysine residues is accessible for the tissue-type plasminogen activator (tPA), and active plasmin cleaves the chromogenic substrate S2251, degrades fibrinogen, and inactivates C3 and C3b. Plasmin attached to swollen A. fumigatus conidia damages human A549 lung epithelial cells, reduces the cellular metabolic activity, and induces cell retraction, which results in exposure of the extracellular matrix. Thus, A. fumigatus AfEno1 is a moonlighting protein and virulence factor which recruits several human regulators. The attached human regulators allow the fungal pathogen to control complement at the level of C3 and to damage endothelial cell layers and tissue components.

Authors: Prasad Dasari, Naile Koleci, Iordana Shopova, D. Wartenberg, Niklas Beyersdorf, Stefanie Dietrich, A. Sahagun-Ruiz, Marc Thilo Figge, Christine Skerka, Axel Brakhage, Peter Zipfel

Date Published: 12th Dec 2019

Journal: Front Immunol

The geographical region of origin determines the phagocytic vulnerability of Lichtheimia strains.
FungiNet A - Aspergillus projects, B4

Abstract (Expand)

Mucormycoses are life-threatening infections that affect patients suffering from immune deficiencies. We performed phagocytosis assays confronting various strains of Lichtheimia species with alveolar … macrophages, which form the first line of defence of the innate immune system. To investigate 17 strains from four different continents in a comparative fashion, transmitted light and confocal fluorescence microscopy was applied in combination with automated image analysis. This interdisciplinary approach enabled the objective and quantitative processing of the big volume of image data. Applying machine-learning supported methods, a spontaneous clustering of the strains was revealed in the space of phagocytic measures. This clustering was not driven by measures of fungal morphology but rather by the geographical origin of the fungal strains. Our study illustrates the crucial contribution of machine-learning supported automated image analysis to the qualitative discovery and quantitative comparison of major factors affecting host-pathogen interactions. We found that the phagocytic vulnerability of Lichtheimia species depends on their geographical origin, where strains within each geographic region behaved similarly, but strongly differed amongst the regions. Based on this clustering, we were able to also classify clinical isolates with regard to their potential geographical origin.

Authors: M. I. A. Hassan, Z. Cseresnyes, N. Al-Zaben, H. M. Dahse, R. J. Vilela de Oliveira, G. Walther, Kerstin Voigt, Marc Thilo Figge

Date Published: 23rd Jul 2019

Journal: Environ Microbiol

On the role of CEACAM receptors during systemic candidiasis
FungiNet total, FungiNet A - Aspergillus projects, A5
No description specified

Creator: Esther Klaile

Contributor: Esther Klaile

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SFB FungiNet: Interns Seminar in Jena A5 & B1 - 9.9.2014

9. September 2014

A5 und B1

Slevogt / Schuster

Start Date: 9th Sep 2014

End Date: Not specified

Event Website: Not specified

Country:  Germany

City: Jena

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