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 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 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 RNA-Sequencing Analyses of Small Bacterial RNAs and their Emergence as Virulence Factors in Host-Pathogen Interactions

2020 ◽  
Vol 21 (5) ◽  
pp. 1627 ◽  
Author(s):  
Idrissa Diallo ◽  
Patrick Provost
Keyword(s):  
Rna Sequencing ◽  
Virulence Factors ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Rna Seq ◽  
Host Pathogen Interactions ◽  
Bioinformatics Analyses ◽  
Additional Layer ◽  
Host Pathogen

Proteins have long been considered to be the most prominent factors regulating so-called invasive genes involved in host-pathogen interactions. The possible role of small non-coding RNAs (sRNAs), either intracellular, secreted or packaged in outer membrane vesicles (OMVs), remained unclear until recently. The advent of high-throughput RNA-sequencing (RNA-seq) techniques has accelerated sRNA discovery. RNA-seq radically changed the paradigm on bacterial virulence and pathogenicity to the point that sRNAs are emerging as an important, distinct class of virulence factors in both gram-positive and gram-negative bacteria. The potential of OMVs, as protectors and carriers of these functional, gene regulatory sRNAs between cells, has also provided an additional layer of complexity to the dynamic host-pathogen relationship. Using a non-exhaustive approach and through examples, this review aims to discuss the involvement of sRNAs, either free or loaded in OMVs, in the mechanisms of virulence and pathogenicity during bacterial infection. We provide a brief overview of sRNA origin and importance and describe the classical and more recent methods of identification that have enabled their discovery, with an emphasis on the theoretical lower limit of RNA sizes considered for RNA sequencing and bioinformatics analyses.

scholarly journals Candida albicans Hyphal Formation and Virulence Assessed Using a Caenorhabditis elegans Infection Model

2009 ◽  
Vol 8 (11) ◽  
pp. 1750-1758 ◽  
Author(s):  
Read Pukkila-Worley ◽  
Anton Y. Peleg ◽  
Emmanouil Tampakakis ◽  
Eleftherios Mylonakis
Keyword(s):  
Candida Albicans ◽  
Caenorhabditis Elegans ◽  
Debaryomyces Hansenii ◽  
Yeast Cells ◽  
Infection Model ◽  
Virulence Determinants ◽  
Tissue Destruction ◽  
C Elegans ◽  
Hyphal Formation

ABSTRACT Candida albicans colonizes the human gastrointestinal tract and can cause life-threatening systemic infection in susceptible hosts. We study here C. albicans virulence determinants using the nematode Caenorhabditis elegans in a pathogenesis system that models candidiasis. The yeast form of C. albicans is ingested into the C. elegans digestive tract. In liquid media, the yeast cells then undergo morphological change to form hyphae, which results in aggressive tissue destruction and death of the nematode. Several lines of evidence demonstrate that hyphal formation is critical for C. albicans pathogenesis in C. elegans. First, two yeast species unable to form hyphae (Debaryomyces hansenii and Candida lusitaniae) were less virulent than C. albicans in the C. elegans assay. Second, three C. albicans mutant strains compromised in their ability to form hyphae (efg1Δ/efg1Δ, flo8Δ/flo8Δ, and cph1Δ/cph1Δ efg1Δ/efg1Δ) were dramatically attenuated for virulence. Third, the conditional tet-NRG1 strain, which enables the external manipulation of morphogenesis in vivo, was more virulent toward C. elegans when the assay was conducted under conditions that permit hyphal growth. Finally, we demonstrate the utility of the C. elegans assay in a screen for C. albicans virulence determinants, which identified several genes important for both hyphal formation in vivo and the killing of C. elegans, including the recently described CAS5 and ADA2 genes. These studies in a C. elegans-C. albicans infection model provide insights into the virulence mechanisms of an important human pathogen.

scholarly journals Caenorhabditis elegans as an Infection Model for Pathogenic Mold and Dimorphic Fungi: Applications and Challenges

2021 ◽  
Vol 11 ◽  
Author(s):  
Chukwuemeka Samson Ahamefule ◽  
Blessing C. Ezeuduji ◽  
James C. Ogbonna ◽  
Anene N. Moneke ◽  
Anthony C. Ike ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Filamentous Fungi ◽  
Virulence Factors ◽  
Antifungal Agents ◽  
Fungal Infections ◽  
Pathogenic Fungi ◽  
Infection Model ◽  
Dimorphic Fungi ◽  
C Elegans

The threat burden from pathogenic fungi is universal and increasing with alarming high mortality and morbidity rates from invasive fungal infections. Understanding the virulence factors of these fungi, screening effective antifungal agents and exploring appropriate treatment approaches in in vivo modeling organisms are vital research projects for controlling mycoses. Caenorhabditis elegans has been proven to be a valuable tool in studies of most clinically relevant dimorphic fungi, helping to identify a number of virulence factors and immune-regulators and screen effective antifungal agents without cytotoxic effects. However, little has been achieved and reported with regard to pathogenic filamentous fungi (molds) in the nematode model. In this review, we have summarized the enormous breakthrough of applying a C. elegans infection model for dimorphic fungi studies and the very few reports for filamentous fungi. We have also identified and discussed the challenges in C. elegans-mold modeling applications as well as the possible approaches to conquer these challenges from our practical knowledge in C. elegans-Aspergillus fumigatus model.

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 Staphylococcus aureus Virulence Factors Identified by Using a High-Throughput Caenorhabditis elegans-Killing Model

2005 ◽  
Vol 73 (2) ◽  
pp. 872-877 ◽  
Author(s):  
Jakob Begun ◽  
Costi D. Sifri ◽  
Samuel Goldman ◽  
Stephen B. Calderwood ◽  
Frederick M. Ausubel
Keyword(s):  
Staphylococcus Aureus ◽  
Caenorhabditis Elegans ◽  
Dna Replication ◽  
Virulence Factors ◽  
High Throughput ◽  
Human Pathogen ◽  
Renal Abscess ◽  
C Elegans ◽  
Transposon Insertion ◽  
Strain Nctc

ABSTRACT Staphylococcus aureus is an important human pathogen that is also able to kill the model nematode Caenorhabditis elegans. We constructed a 2,950-member Tn917 transposon insertion library in S. aureus strain NCTC 8325. Twenty-one of these insertions exhibited attenuated C. elegans killing, and of these, 12 contained insertions in different genes or chromosomal locations. Ten of these 12 insertions showed attenuated killing phenotypes when transduced into two different S. aureus strains, and 5 of the 10 mutants correspond to genes that have not been previously identified in signature-tagged mutagenesis studies. These latter five mutants were tested in a murine renal abscess model, and one mutant harboring an insertion in nagD exhibited attenuated virulence. Interestingly, Tn917 was shown to have a very strong bias for insertions near the terminus of DNA replication.

scholarly journals Identification of Burkholderia cenocepacia Strain H111 Virulence Factors Using Nonmammalian Infection Hosts

2012 ◽  
Vol 81 (1) ◽  
pp. 143-153 ◽  
Author(s):  
Stephan Schwager ◽  
Kirsty Agnoli ◽  
Manuela Köthe ◽  
Friederike Feldmann ◽  
Michael Givskov ◽  
...  
Keyword(s):  
Virulence Factors ◽  
Galleria Mellonella ◽  
Burkholderia Cenocepacia ◽  
Infection Model ◽  
Extracellular Proteases ◽  
Content Type ◽  
C Elegans ◽  
Content Model ◽  
Genes Encoding ◽  
Insertion Mutants

Burkholderia cenocepaciaH111, a strain isolated from a cystic fibrosis patient, has been shown to effectively kill the nematodeCaenorhabditis elegans. We used theC. elegansmodel of infection to screen a mini-Tn5mutant library ofB. cenocepaciaH111 for attenuated virulence. Of the approximately 5,500B. cenocepaciaH111 random mini-Tn5insertion mutants that were screened, 22 showed attenuated virulence inC. elegans. Except for the quorum-sensing regulatorcepR, none of the mutated genes coded for the biosynthesis of classical virulence factors such as extracellular proteases or siderophores. Instead, the mutants contained insertions in metabolic and regulatory genes. Mutants attenuated in virulence in theC. elegansinfection model were also tested in theDrosophila melanogasterpricking model, and those also attenuated in this model were further tested inGalleria mellonella. Six of the 22 mutants were attenuated inD. melanogaster, and five of these were less pathogenic in theG. mellonellamodel. We show that genes encoding enzymes of the purine, pyrimidine, and shikimate biosynthesis pathways are critical for virulence in multiple host models of infection.

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