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B4

Overview

Image data analysis and agent-based modelling of the spatio-temporal interaction between immune cells and human-pathogenic fungi

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

SEEK ID: https://funginet.hki-jena.de/projects/27

Public web page: http://www.funginet.de/project-b4.html

Organisms: Aspergillus fumigatus, Candida albicans

INF PALs: No PALs for this Project

Project created: 21st Jul 2015

Related items

Stefanie Dietrich : inactive since 2020-06-09

Projects: B4, FungiNet total, FungiNet B - Bioinformatics projects

Institutions: Leibniz-Institute for Natural Product Research and Infection Biology Hans Knöll Institute (HKI)

Marc Thilo Figge project_administrator

Projects: FungiNet total, FungiNet B - Bioinformatics projects, B4

Institutions: Leibniz-Institute for Natural Product Research and Infection Biology Hans Knöll Institute (HKI), Friedrich-Schiller-University

https://orcid.org/0000-0002-4044-9166
Peter Großmann programme_administrator: inactive since 2020-06-01

Projects: FungiNet total, INF, A1, A2, A3, A4 (E), A5, A6, B1, B3 (E), B4, B5, C1, C2, C3, C4 (E), C5, C6 (E), Z1, Z2, FungiNet A - Aspergillus projects, FungiNet B - Bioinformatics projects, FungiNet C - Candida projects, B2

Institutions: Leibniz-Institute for Natural Product Research and Infection Biology Hans Knöll Institute (HKI)

https://orcid.org/0000-0001-6106-724X
Kaswara Kraibooj : inactive since 2018-06-07

Projects: B4

Institutions: Leibniz-Institute for Natural Product Research and Infection Biology Hans Knöll Institute (HKI)

Teresa Lehnert

Projects: B4

Institutions: Leibniz-Institute for Natural Product Research and Infection Biology Hans Knöll Institute (HKI)

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Cell track generator
B4

README
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This package contains code that generates and analyses tracks in 2D given three
distinct condition; non-persistent, persistent and directed by the
Ornstein-Uhlenbeck process. Full details on the analysis can be found in the
article "Svensson et al., Untangling cell tracks: quantifying cell migration by
time lapse image data analysis, Cytometry Pt A, 2017". The paper can be found
on
...

Creator: Carl-Magnus Svensson

Contributor: Carl-Magnus Svensson

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State-based model of whole-blood infection assay with PMN-mediated immune evasion mechanism
B4

This model is a variant of the previously developed SBM of whole-blood infection assay. While in the previous model a spontaneous immune evasion mechanism (A) was implemented in this model immune evasion was caused by PMN molecule secretion (B).

Creators: Teresa Lehnert, Maria T. E. Prauße

Contributor: Sandra Timme

State-based model of whole-blood infection assays with Candida albicans
B4

The state-based model (SBM) allow to simulate the interplay between innate immune cells, such as monocytes and PMN, and Candida albicans and to quantify immune reaction rates like phagocytosis and killing rates. It is implemented in C++.

Creator: Teresa Lehnert

Contributor: Sandra Timme

DynaCoSys
B4

DynaCoSys models the complement system by using a combination of Ordinary and Partial Differential Equations.

Creators: Teresa Lehnert, Alexander Tille

Contributor: Sandra Timme

Virtual infection model of Aspergillus fumigatus in a murine alveolus
B4

Adaptation of the previously developed virtual infection model of Aspergillus fumigatus in a *human* alveolus.
This model comprises a hybrid agent-based model of a single murine alveolus. The alveolus is represented in a realistic to-scale representation and contains the cell types of alveolar epithelial cells (AEC) of type 1 and 2 as well as the pores of Kohn (PoK).
Furthermore, in this model, depending on the infection dose multiple A. fumigatus conidium are inserted into the alveolus and the
...

Creators: Sandra Timme, Marco Blickensdorf

Contributor: Sandra Timme

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Quantification of Factor H Mediated Self vs. Non-self Discrimination by Mathematical Modeling.
FungiNet C - Candida projects, B4

Abstract (Expand)

The complement system is part of the innate immune system and plays an important role in the host defense against infectious pathogens. One of the main effects is the opsonization of foreign invaders … and subsequent uptake by phagocytosis. Due to the continuous default basal level of active complement molecules, a tight regulation is required to protect the body's own cells (self cells) from opsonization and from complement damage. A major complement regulator is Factor H, which is recruited from the fluid phase and attaches to cell surfaces where it effectively controls complement activation. Besides self cells, pathogens also have the ability to bind Factor H; they can thus escape opsonization and phagocytosis causing severe infections. In order to advance our understanding of the opsonization process at a quantitative level, we developed a mathematical model for the dynamics of the complement system-termed DynaCoSys model-that is based on ordinary differential equations for cell surface-bound molecules and on partial differential equations for concentration profiles of the fluid phase molecules in the environment of cells. This hybrid differential equation approach allows to model the complement cascade focusing on the role of active C3b in the fluid phase and on the cell surface as well as on its inactivation on the cell surface. The DynaCoSys model enables us to quantitatively predict the conditions under which Factor H mediated complement evasion occurs. Furthermore, investigating the quantitative impact of model parameters by a sensitivity analysis, we identify the driving processes of complement activation and regulation in both the self and non-self regime. The two regimes are defined by a critical Factor H concentration on the cell surface and we use the model to investigate the differential impact of complement model parameters on this threshold value. The dynamic modeling on the surface of pathogens are further relevant to understand pathophysiological situations where Factor H mutants and defective Factor H binding to target surfaces results in pathophysiology such as renal and retinal disease. In the future, this DynaCoSys model will be extended to also enable evaluating treatment strategies of complement-related diseases.

Authors: A. Tille, Teresa Lehnert, Peter Zipfel, Marc Thilo Figge

Date Published: 5th Oct 2020

Journal: Front Immunol

Hybrid Agent-Based Modeling of Aspergillus fumigatus Infection to Quantitatively Investigate the Role of Pores of Kohn in Human Alveoli.
B4

Abstract (Expand)

The healthy state of an organism is constantly threatened by external cues. Due to the daily inhalation of hundreds of particles and pathogens, the immune system needs to constantly accomplish the task … of pathogen clearance in order to maintain this healthy state. However, infection dynamics are highly influenced by the peculiar anatomy of the human lung. Lung alveoli that are packed in alveolar sacs are interconnected by so called Pores of Kohn. Mainly due to the lack of in vivo methods, the role of Pores of Kohn in the mammalian lung is still under debate and partly contradicting hypotheses remain to be investigated. Although it was shown by electron microscopy that Pores of Kohn may serve as passageways for immune cells, their impact on the infection dynamics in the lung is still unknown under in vivo conditions. In the present study, we apply a hybrid agent-based infection model to quantitatively compare three different scenarios and discuss the importance of Pores of Kohn during infections of Aspergillus fumigatus. A. fumigatus is an airborne opportunistic fungus with rising incidences causing severe infections in immunocompromised patients that are associated with high mortality rates. Our hybrid agent-based model incorporates immune cell dynamics of alveolar macrophages - the resident phagocytes in the lung - as well as molecular dynamics of diffusing chemokines that attract alveolar macrophages to the site of infection. Consequently, this model allows a quantitative comparison of three different scenarios and to study the importance of Pores of Kohn. This enables us to demonstrate how passaging of alveolar macrophages and chemokine diffusion affect A. fumigatus infection dynamics. We show that Pores of Kohn alter important infection clearance mechanisms, such as the spatial distribution of macrophages and the effect of chemokine signaling. However, despite these differences, a lack of passageways for alveolar macrophages does impede infection clearance only to a minor extend. Furthermore, we quantify the importance of recruited macrophages in comparison to resident macrophages.

Authors: M. Blickensdorf, Sandra Timme, Marc Thilo Figge

Date Published: 9th Sep 2020

Journal: Front Microbiol

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

Functional surface proteomic profiling reveals the host heat-shock protein A8 as a mediator of Lichtheimia corymbifera recognition by murine alveolar macrophages.
A1, A5, B4, Z2, A6

Abstract (Expand)

Mucormycosis is an emergent, fatal fungal infection of humans and warm-blooded animals caused by species of the order Mucorales. Immune cells of the innate immune system serve as the first line of … defence against inhaled spores. Alveolar macrophages were challenged with the mucoralean fungus Lichtheimia corymbifera and subjected to biotinylation and streptavidin enrichment procedures followed by LC-MS/MS analyses. A total of 28 host proteins enriched for binding to macrophage-L. corymbifera interaction. Among those, the HSP70-family protein Hspa8 was found to be predominantly responsive to living and heat-killed spores of a virulent and an attenuated strain of L. corymbifera. Confocal scanning laser microscopy of infected macrophages revealed colocalization of Hspa8 with phagocytosed spores of L. corymbifera. The amount of detectable Hspa8 was dependent on the multiplicity of infection. Incubation of alveolar macrophages with an anti-Hspa8 antibody prior to infection reduced their capability to phagocytose spores of L. corymbifera. In contrast, anti-Hspa8 antibodies did not abrogate the phagocytosis of Aspergillus fumigatus conidia by macrophages. These results suggest an important contribution of the heat-shock family protein Hspa8 in the recognition of spores of the mucoralean fungus L. corymbifera by host alveolar macrophages and define a potential immunomodulatory therapeutic target.

Authors: M. I. A. Hassan, J. M. Kruse, Thomas Krüger, H. M. Dahse, Z. Cseresnyes, M. G. Blango, Hortense Slevogt, F. Horhold, V. Ast, R. Konig, Marc Thilo Figge, Olaf Kniemeyer, Axel Brakhage, Kerstin Voigt

Date Published: 26th Jun 2020

Journal: Environ Microbiol

B4 - Automated Characterisation of Neutrophil Activation Phenotypes in Ex Vivo Human Candida Bloodstream Infections
B4
No description specified

Creator: Jan-Philipp Praetorius

Contributor: Jan-Philipp Praetorius

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FungiNet Project B4 – Image data analysis and agent-based modelling of the spatio-temporal interaction between immune cells and human-pathogenic fungi
B4

Overview of Project B4 and presentation of a state-based model regarding the immune evasion of C. albicans in human whole-blood infection assays

Creator: Sandra Timme

Contributor: Sandra Timme

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