scholarly journals Investigation of the host transcriptional response to intracellular bacterial infection using Dictyostelium discoideum as a host model

BMC Genomics ◽  
2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Jonas Kjellin ◽  
Maria Pränting ◽  
Frauke Bach ◽  
Roshan Vaid ◽  
Bart Edelbroek ◽  
...  
Keyword(s):  
Dictyostelium Discoideum ◽  
High Throughput ◽  
Legionella Pneumophila ◽  
Transcriptional Response ◽  
Infection Model ◽  
Intracellular Pathogens ◽  
Host Pathogen Interactions ◽  
Human Macrophages ◽  
Wide Range ◽  
Host Pathogen

Abstract Background During infection by intracellular pathogens, a highly complex interplay occurs between the infected cell trying to degrade the invader and the pathogen which actively manipulates the host cell to enable survival and proliferation. Many intracellular pathogens pose important threats to human health and major efforts have been undertaken to better understand the host-pathogen interactions that eventually determine the outcome of the infection. Over the last decades, the unicellular eukaryote Dictyostelium discoideum has become an established infection model, serving as a surrogate macrophage that can be infected with a wide range of intracellular pathogens. In this study, we use high-throughput RNA-sequencing to analyze the transcriptional response of D. discoideum when infected with Mycobacterium marinum and Legionella pneumophila. The results were compared to available data from human macrophages. Results The majority of the transcriptional regulation triggered by the two pathogens was found to be unique for each bacterial challenge. Hallmark transcriptional signatures were identified for each infection, e.g. induction of endosomal sorting complexes required for transport (ESCRT) and autophagy genes in response to M. marinum and inhibition of genes associated with the translation machinery and energy metabolism in response to L. pneumophila. However, a common response to the pathogenic bacteria was also identified, which was not induced by non-pathogenic food bacteria. Finally, comparison with available data sets of regulation in human monocyte derived macrophages shows that the elicited response in D. discoideum is in many aspects similar to what has been observed in human immune cells in response to Mycobacterium tuberculosis and L. pneumophila. Conclusions Our study presents high-throughput characterization of D. discoideum transcriptional response to intracellular pathogens using RNA-seq. We demonstrate that the transcriptional response is in essence distinct to each pathogen and that in many cases, the corresponding regulation is recapitulated in human macrophages after infection by mycobacteria and L. pneumophila. This indicates that host-pathogen interactions are evolutionary conserved, derived from the early interactions between free-living phagocytic cells and bacteria. Taken together, our results strengthen the use of D. discoideum as a general infection model.

scholarly journals Intracellular Growth of Legionella pneumophila in Dictyostelium discoideum, a System for Genetic Analysis of Host-Pathogen Interactions

2000 ◽  
Vol 68 (5) ◽  
pp. 2939-2947 ◽  
Author(s):  
Jonathan M. Solomon ◽  
Adam Rupper ◽  
James A. Cardelli ◽  
Ralph R. Isberg
Keyword(s):  
Genetic Analysis ◽  
Dictyostelium Discoideum ◽  
Legionella Pneumophila ◽  
Bacterial Pathogen ◽  
Intracellular Growth ◽  
Host Pathogen Interactions ◽  
Growth State ◽  
Myosin I ◽  
Host Pathogen ◽  
Endocytic Compartments

ABSTRACT Conditions were established in which Legionella pneumophila, an intracellular bacterial pathogen, could replicate within the unicellular organism Dictyostelium discoideum. By several criteria, L. pneumophila grew by the same mechanism within D. discoideum as it does in amoebae and macrophages. Bacteria grew within membrane-bound vesicles associated with rough endoplasmic reticulum, and L. pneumophila dot/icm mutants, blocked for growth in macrophages and amoebae, also did not grow in D. discoideum. Internalized L. pneumophila avoided degradation by D. discoideum and showed evidence of reduced fusion with endocytic compartments. The ability of L. pneumophila to grow within D. discoideum depended on the growth state of the cells. D. discoideum grown as adherent monolayers was susceptible toL. pneumophila infection and to contact-dependent cytotoxicity during high-multiplicity infections, whereas D. discoideum grown in suspension was relatively resistant to cytotoxicity and did not support intracellular growth. Some knownD. discoideum mutants were examined for their effect on growth of L. pneumophila. The coronin mutant and themyoA/B double myosin I mutant were more permissive than wild-type strains for intracellular growth. Growth of L. pneumophila in a Gβ mutant was slightly reduced compared to the parent strain. This work demonstrates the usefulness of the L. pneumophila-D. discoideum system for genetic analysis of host-pathogen interactions.

scholarly journals Development and Characterization of High-Throughput Caenorhabditis elegans – Enterococcus faecium Infection Model

2021 ◽  
Vol 11 ◽  
Author(s):  
Alexey V. Revtovich ◽  
Elissa Tjahjono ◽  
Kavindra V. Singh ◽  
Blake M. Hanson ◽  
Barbara E. Murray ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Virulence Factors ◽  
High Throughput ◽  
World Health ◽  
Infection Model ◽  
Virulence Determinants ◽  
Host Pathogen Interactions ◽  
C Elegans ◽  
Host Pathogen ◽  
Host Death

The genus Enterococcus includes two Gram-positive pathogens of particular clinical relevance: E. faecalis and E. faecium. Infections with each of these pathogens are becoming more frequent, particularly in the case of hospital-acquired infections. Like most other bacterial species of clinical importance, antimicrobial resistance (and, specifically, multi-drug resistance) is an increasing threat, with both species considered to be of particular importance by the World Health Organization and the US Centers for Disease Control. The threat of antimicrobial resistance is exacerbated by the staggering difference in the speeds of development for the discovery and development of the antimicrobials versus resistance mechanisms. In the search for alternative strategies, modulation of host-pathogen interactions in general, and virulence inhibition in particular, have drawn substantial attention. Unfortunately, these approaches require a fairly comprehensive understanding of virulence determinants. This requirement is complicated by the fact that enterococcal infection models generally require vertebrates, making them slow, expensive, and ethically problematic, particularly when considering the thousands of animals that would be needed for the early stages of experimentation. To address this problem, we developed the first high-throughput C. elegans–E. faecium infection model involving host death. Importantly, this model recapitulates many key aspects of murine peritonitis models, including utilizing similar virulence determinants. Additionally, host death is independent of peroxide production, unlike other E. faecium–C. elegans virulence models, which allows the assessment of other virulence factors. Using this system, we analyzed a panel of lab strains with deletions of targeted virulence factors. Although removal of certain virulence factors (e.g., Δfms15) was sufficient to affect virulence, multiple deletions were generally required to affect pathogenesis, suggesting that host-pathogen interactions are multifactorial. These data were corroborated by genomic analysis of selected isolates with high and low levels of virulence. We anticipate that this platform will be useful for identifying new treatments for E. faecium infection.

scholarly journals Dual Transcriptomic Analyses Unveil Host–Pathogen Interactions Between Salmonella enterica Serovar Enteritidis and Laying Ducks (Anas platyrhynchos)

2021 ◽  
Vol 12 ◽  
Author(s):  
Yu Zhang ◽  
Lina Song ◽  
Lie Hou ◽  
Zhengfeng Cao ◽  
Wanwipa Vongsangnak ◽  
...  
Keyword(s):  
Food Poisoning ◽  
Systemic Infection ◽  
Egg Laying ◽  
Cytokine Receptor ◽  
Differentially Expressed ◽  
Receptor Interaction ◽  
Infection Model ◽  
Host Pathogen Interactions ◽  
Related Factors ◽  
Host Pathogen

Salmonella enteritidis (SE) is a pathogen that can readily infect ovarian tissues and colonize the granulosa cell layer such that it can be transmitted via eggs from infected poultry to humans in whom it can cause food poisoning. Ducks are an important egg-laying species that are susceptible to SE infection, yet the host–pathogen interactions between SE and ducks have not been thoroughly studied to date. Herein, we performed dual RNA-sequencing analyses of these two organisms in a time-resolved infection model of duck granulosa cells (dGCs) by SE. In total, 10,510 genes were significantly differentially expressed in host dGCs, and 265 genes were differentially expressed in SE over the course of infection. These differentially expressed genes (DEGs) of dGCs were enriched in the cytokine–cytokine receptor interaction pathway via KEGG analyses, and the DEGs in SE were enriched in the two-component system, bacterial secretion system, and metabolism of pathogen factors pathways as determined. A subsequent weighted gene co-expression network analysis revealed that the cytokine–cytokine receptor interaction pathway is mostly enriched at 6 h post-infection (hpi). Moreover, a number of pathogenic factors identified in the pathogen–host interaction database (PHI-base) are upregulated in SE, including genes encoding the pathogenicity island/component, type III secretion, and regulators of systemic infection. Furthermore, an intracellular network associated with the regulation of SE infection in ducks was constructed, and 16 cytokine response-related dGCs DEGs (including IL15, CD40, and CCR7) and 17 pathogenesis-related factors (including sseL, ompR, and fliC) were identified, respectively. Overall, these results not only offer new insights into the mechanisms underlying host–pathogen interactions between SE and ducks, but they may also aid in the selection of potential targets for antimicrobial drug development.

scholarly journals Determinants of Phagosomal pH During Host-Pathogen Interactions

2021 ◽  
Vol 8 ◽  
Author(s):  
Johannes Westman ◽  
Sergio Grinstein
Keyword(s):  
Host Cell ◽  
Microbial Growth ◽  
Intracellular Pathogens ◽  
Ion Permeation ◽  
Host Pathogen Interactions ◽  
Counter Ion ◽  
Regulatory Machinery ◽  
Different Types ◽  
Host Pathogen ◽  
Luminal Ph

The ability of phagosomes to halt microbial growth is intimately linked to their ability to acidify their luminal pH. Establishment and maintenance of an acidic lumen requires precise co-ordination of H+ pumping and counter-ion permeation to offset the countervailing H+ leakage. Despite the best efforts of professional phagocytes, however, a number of specialized pathogens survive and even replicate inside phagosomes. In such instances, pathogens target the pH-regulatory machinery of the host cell in an effort to survive inside or escape from phagosomes. This review aims to describe how phagosomal pH is regulated during phagocytosis, why it varies in different types of professional phagocytes and the strategies developed by prototypical intracellular pathogens to manipulate phagosomal pH to survive, replicate, and eventually escape from the phagocyte.

scholarly journals Human macrophages utilize a wide range of pathogen recognition receptors to recognize Legionella pneumophila, including Toll-Like Receptor 4 engaging Legionella lipopolysaccharide and the Toll-like Receptor 3 nucleic-acid sensor

2021 ◽  
Vol 17 (7) ◽  
pp. e1009781
Author(s):  
Lubov S. Grigoryeva ◽  
Nicholas P. Cianciotto
Keyword(s):  
Nucleic Acid ◽  
Legionella Pneumophila ◽  
Critical Role ◽  
U937 Cells ◽  
Toll Like Receptor ◽  
Lectin Receptors ◽  
Macrophage Response ◽  
Human Macrophages ◽  
Wide Range ◽  
Pathogen Recognition Receptors

Cytokines made by macrophages play a critical role in determining the course of Legionella pneumophila infection. Prior murine-based modeling indicated that this cytokine response is initiated upon recognition of L. pneumophila by a subset of Toll-like receptors, namely TLR2, TLR5, and TLR9. Through the use of shRNA/siRNA knockdowns and subsequently CRISPR/Cas9 knockouts (KO), we determined that TRIF, an adaptor downstream of endosomal TLR3 and TLR4, is required for full cytokine secretion by human primary and cell-line macrophages. By characterizing a further set of TLR KO’s in human U937 cells, we discerned that, contrary to the viewpoint garnered from murine-based studies, TLR3 and TLR4 (along with TLR2 and TLR5) are in fact vital to the macrophage response in the early stages of L. pneumophila infection. This conclusion was bolstered by showing that i) chemical inhibitors of TLR3 and TLR4 dampen the cytokine output of primary human macrophages and ii) transfection of TLR3 and TLR4 into HEK cells conferred an ability to sense L. pneumophila. TLR3- and TLR4-dependent cytokines promoted migration of human HL-60 neutrophils across an epithelial layer, pointing to the biological importance for the newfound signaling pathway. The response of U937 cells to L. pneumophila LPS was dependent upon TLR4, a further contradiction to murine-based studies, which had concluded that TLR2 is the receptor for Legionella LPS. Given the role of TLR3 in sensing nucleic acid (i.e., dsRNA), we utilized newly-made KO U937 cells to document that DNA-sensing by cGAS-STING and DNA-PK are also needed for the response of human macrophages to L. pneumophila. Given the lack of attention given them in the bacterial field, C-type lectin receptors were similarly examined; but, they were not required. Overall, this study arguably represents the most extensive, single-characterization of Legionella-recognition receptors within human macrophages.

Uncovering complex molecular networks in host–pathogen interactions using systems biology

2019 ◽  
Vol 3 (4) ◽  
pp. 371-378
Author(s):  
Joshua M. Peters ◽  
Sydney L. Solomon ◽  
Christopher Y. Itoh ◽  
Bryan D. Bryson
Keyword(s):  
Systems Biology ◽  
High Throughput ◽  
Cell Biology ◽  
Molecular Networks ◽  
Host Pathogen Interactions ◽  
Exciting Field ◽  
Specific Host ◽  
Biomolecular Network ◽  
Host Pathogen ◽  
Analytical Frameworks

Abstract Interactions between pathogens and their hosts can induce complex changes in both host and pathogen states to privilege pathogen survival or host clearance of the pathogen. To determine the consequences of specific host–pathogen interactions, a variety of techniques in microbiology, cell biology, and immunology are available to researchers. Systems biology that enables unbiased measurements of transcriptomes, proteomes, and other biomolecules has become increasingly common in the study of host–pathogen interactions. These approaches can be used to generate novel hypotheses or to characterize the effects of particular perturbations across an entire biomolecular network. With proper experimental design and complementary data analysis tools, high-throughput omics techniques can provide novel insights into the mechanisms that underlie processes from phagocytosis to pathogen immune evasion. Here, we provide an overview of the suite of biochemical approaches for high-throughput analyses of host–pathogen interactions, analytical frameworks for understanding the resulting datasets, and a vision for the future of this exciting field.

scholarly journals Peptidylarginine Deiminase (PAD) and Post-Translational Protein Deimination—Novel Insights into Alveolata Metabolism, Epigenetic Regulation and Host–Pathogen Interactions

Biology ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 177
Author(s):  
Árni Kristmundsson ◽  
Ásthildur Erlingsdóttir ◽  
Sigrun Lange
Keyword(s):  
Epigenetic Regulation ◽  
Protein Function ◽  
Genetic Regulation ◽  
Histone H3 ◽  
Neutrophil Extracellular Trap ◽  
Parasite Development ◽  
Host Pathogen Interactions ◽  
Enzyme Family ◽  
Wide Range ◽  
Host Pathogen

The alveolates (Superphylum Alveolata) comprise a group of primarily single-celled eukaryotes that have adopted extremely diverse modes of nutrition, such as predation, photoautotrophy and parasitism. The alveolates consists of several major phyla including the apicomplexans, a large group of unicellular, spore forming obligate intracellular parasites, and chromerids, which are believed to be the phototrophic ancestors of the parasitic apicomplexans. Molecular pathways involved in Alveolata host–pathogen interactions, epigenetic regulation and metabolism in parasite development remain to be fully understood. Peptidylarginine deiminases (PADs) are a phylogenetically conserved enzyme family which causes post-translational protein deimination, affecting protein function through the conversion of arginine to citrulline in a wide range of target proteins, contributing to protein moonlighting in physiological and pathological processes. The identification of deiminated protein targets in alveolate parasites may therefore provide novel insight into pathogen survival and host-pathogen interactions. The current study assessed PAD homologues and deiminated protein profiles of two alveolate parasites, Piridium sociabile (Chromerida) and Merocystis kathae (Apicomplexa). Histological analysis verified strong cytoplasmic PAD expression in both Alveolates, detected deiminated proteins in nuclear and cytoplasmic compartments of the alveolate parasites and verified the presence of citrullinated histone H3 in Alveolata nucleus, indicating roles in epigenetic regulation. Histone H3 citrullination was also found significantly elevated in the host tissue, indicative of neutrophil extracellular trap formation, a host-defence mechanism against a range of pathogens, particularly those that are too large for phagocytosis. Proteomic analysis of deiminated proteins from both Alveolata identified GO and KEGG pathways strongly relating to metabolic and genetic regulation, with some species-specific differences between the apicomplexan and the chromerid. Our findings provide novel insights into roles for the conserved PAD/ADI enzyme family in the regulation of metabolic and epigenetic pathways in alveolate parasites, possibly also relating to their life cycle and host–pathogen interactions.

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