Interactions between adherent-invasive Escherichia coli and host macrophages: a virulence phenotype.

10.32920/ryerson.14636934.v1 ◽

2021 ◽

Author(s):

Michael John Dill Renouf

Keyword(s):

Escherichia Coli ◽

Secondary Infection ◽

Opportunistic Pathogen ◽

Intracellular Survival ◽

Western World ◽

Infection Model ◽

Raw264.7 Macrophages ◽

Bacterial Uptake ◽

Inflammatory Bowel ◽

Insight Into

Inflammatory bowel disease (IBD) is a chronic condition increasing in prevalence throughout the western world and in developing countries. Adherent-invasive Escherichia coli (AIEC) are an opportunistic pathogen associated with IBD. Well-characterized genetic risk factors for IBD include mutations in genes associated with host-cell autophagy. A phenotype of interest in AIEC pathogenesis is survival within host macrophages. Intracellular survival of AIEC strains has been correlated with existing virulence factors but no single factor has been identified to explain this behaviour. In this thesis, infections of RAW264.7 macrophages with AIEC strains from diverse sources demonstrates increased frequency of both bacterial uptake and intracellular survival in disease-associated strains. A secondary infection model reveals the effect of primary AIEC infection on downstream macrophage function and a novel phenotype was identified in the disease-associated strain HM605. Co-localization using fluorescence microscopy shows changes in intracellular trafficking of HM605. This work aims to provide insight into one bacterial phenotype that contributes to the development of disease

Download Full-text

Escherichia coli UropathogenesisIn Vitro: Invasion, Cellular Escape, and Secondary Infection Analyzed in a Human Bladder Cell Infection Model

Infection and Immunity ◽

10.1128/iai.06075-11 ◽

2012 ◽

Vol 80 (5) ◽

pp. 1858-1867 ◽

Cited By ~ 40

Author(s):

Thomas E. Andersen ◽

Surabhi Khandige ◽

Michelle Madelung ◽

Jonathan Brewer ◽

Hans J. Kolmos ◽

...

Keyword(s):

Escherichia Coli ◽

Bacterial Colonization ◽

Secondary Infection ◽

Infection Model ◽

Luminal Surface ◽

Filamentous Bacteria ◽

Cell Infection ◽

Human Bladder ◽

Bladder Cell

ABSTRACTUropathogenicEscherichia coli(UPEC) strains are capable of invading bladder epithelial cells (BECs) on the bladder luminal surface. Based primarily on studies in mouse models, invasion is proposed to trigger an intracellular uropathogenic cascade involving intracellular bacterial proliferation followed by escape of elongated, filamentous bacteria from colonized BECs. UPEC filaments on the mouse bladder epithelium are able to revert to rod-shaped bacteria, which are believed to invade neighboring cells to initiate new rounds of intracellular colonization. So far, however, these late-stage infection events have not been replicatedin vitro. We have established anin vitromodel of human bladder cell infection by the use of a flow chamber (FC)-based culture system, which allows investigation of steps subsequent to initial invasion. Short-term bacterial colonization on the FC-BEC layer led to intracellular colonization. Exposing invaded BECs to a flow of urine, i.e., establishing conditions similar to those faced by UPEC reemerging on the bladder luminal surface, led to outgrowth of filamentous bacteria similar to what has been reported to occur in mice. These filaments were capable of reverting to rods that could invade other BECs. Hence, under growth conditions established to resemble those presentin vivo, the elements of the proposed uropathogenic cascade were inducible in a human BEC model system. Here, we describe the model and show how these characteristics are reproducedin vitro.

Download Full-text

Faculty Opinions recommendation of A novel application of gene arrays: Escherichia coli array provides insight into the biology of the obligate endosymbiont of tsetse flies.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1001143.17660 ◽

2001 ◽

Author(s):

Sara Melville

Keyword(s):

Escherichia Coli ◽

Tsetse Flies ◽

Gene Arrays ◽

Insight Into ◽

Obligate Endosymbiont

Download Full-text

An infection-induced RhoB-Beclin 1-Hsp90 complex enhances clearance of uropathogenic Escherichia coli

Nature Communications ◽

10.1038/s41467-021-22726-8 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Chunhui Miao ◽

Mingyu Yu ◽

Geng Pei ◽

Zhenyi Ma ◽

Lisong Zhang ◽

...

Keyword(s):

Escherichia Coli ◽

Treatment Strategies ◽

Uropathogenic Escherichia Coli ◽

Beclin 1 ◽

Host Cells ◽

Infection Model ◽

Intracellular Bacteria ◽

Bladder Epithelium ◽

Binding Residue

AbstractHost cells use several anti-bacterial pathways to defend against pathogens. Here, using a uropathogenic Escherichia coli (UPEC) infection model, we demonstrate that bacterial infection upregulates RhoB, which subsequently promotes intracellular bacteria clearance by inducing LC3 lipidation and autophagosome formation. RhoB binds with Beclin 1 through its residues at 118 to 140 and the Beclin 1 CCD domain, with RhoB Arg133 being the key binding residue. Binding of RhoB to Beclin 1 enhances the Hsp90-Beclin 1 interaction, preventing Beclin 1 degradation. RhoB also directly interacts with Hsp90, maintaining RhoB levels. UPEC infections increase RhoB, Beclin 1 and LC3 levels in bladder epithelium in vivo, whereas Beclin 1 and LC3 levels as well as UPEC clearance are substantially reduced in RhoB+/− and RhoB−/− mice upon infection. We conclude that when stimulated by UPEC infections, host cells promote UPEC clearance through the RhoB-Beclin 1-HSP90 complex, indicating RhoB may be a useful target when developing UPEC treatment strategies.

Download Full-text

The role of epigenetic modifications for the pathogenesis of Crohn's disease

Clinical Epigenetics ◽

10.1186/s13148-021-01089-3 ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

M. Hornschuh ◽

E. Wirthgen ◽

M. Wolfien ◽

K. P. Singh ◽

O. Wolkenhauer ◽

...

Keyword(s):

Crohn’S Disease ◽

Crohn's Disease ◽

Adaptive Immune Response ◽

Adaptive Immune ◽

Bowel Diseases ◽

Inflammatory Bowel ◽

New Biomarkers ◽

Insight Into ◽

Specific Evaluation

AbstractEpigenetics has become a promising field for finding new biomarkers and improving diagnosis, prognosis, and drug response in inflammatory bowel disease. The number of people suffering from inflammatory bowel diseases, especially Crohn's disease, has increased remarkably. Crohn's disease is assumed to be the result of a complex interplay between genetic susceptibility, environmental factors, and altered intestinal microbiota, leading to dysregulation of the innate and adaptive immune response. While many genetic variants have been identified to be associated with Crohn's disease, less is known about the influence of epigenetics in the pathogenesis of this disease. In this review, we provide an overview of current epigenetic studies in Crohn's disease. In particular, we enable a deeper insight into applied bioanalytical and computational tools, as well as a comprehensive update toward the cell-specific evaluation of DNA methylation and histone modifications.

Download Full-text

Iron Acquisition of Urinary Tract Infection Escherichia coli Involves Pathogenicity in Caenorhabditis elegans

Microorganisms ◽

10.3390/microorganisms9020310 ◽

2021 ◽

Vol 9 (2) ◽

pp. 310

Author(s):

Masayuki Hashimoto ◽

Yi-Fen Ma ◽

Sin-Tian Wang ◽

Chang-Shi Chen ◽

Ching-Hao Teng

Keyword(s):

Escherichia Coli ◽

Urinary Tract ◽

Caenorhabditis Elegans ◽

Large Scale ◽

Iron Acquisition ◽

Infection Model ◽

High Throughput Analysis ◽

E Coli ◽

C Elegans ◽

Tract Infections

Uropathogenic Escherichia coli (UPEC) is a major bacterial pathogen that causes urinary tract infections (UTIs). The mouse is an available UTI model for studying the pathogenicity; however, Caenorhabditis elegans represents as an alternative surrogate host with the capacity for high-throughput analysis. Then, we established a simple assay for a UPEC infection model with C. elegans for large-scale screening. A total of 133 clinically isolated E. coli strains, which included UTI-associated and fecal isolates, were applied to demonstrate the simple pathogenicity assay. From the screening, several virulence factors (VFs) involved with iron acquisition (chuA, fyuA, and irp2) were significantly associated with high pathogenicity. We then evaluated whether the VFs in UPEC were involved in the pathogenicity. Mutants of E. coli UTI89 with defective iron acquisition systems were applied to a solid killing assay with C. elegans. As a result, the survival rate of C. elegans fed with the mutants significantly increased compared to when fed with the parent strain. The results demonstrated, the simple assay with C. elegans was useful as a UPEC infectious model. To our knowledge, this is the first report of the involvement of iron acquisition in the pathogenicity of UPEC in a C. elegans model.

Download Full-text

Mechanistic insights into synergy between nalidixic acid and tetracycline against clinical isolates of Acinetobacter baumannii and Escherichia coli

Communications Biology ◽

10.1038/s42003-021-02074-5 ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Amit Gaurav ◽

Varsha Gupta ◽

Sandeep K. Shrivastava ◽

Ranjana Pathania

Keyword(s):

Escherichia Coli ◽

Acinetobacter Baumannii ◽

Nalidixic Acid ◽

Bacterial Infections ◽

Clinical Isolates ◽

Hospital Environment ◽

Infection Model ◽

Drug Resistant ◽

E Coli

AbstractThe increasing prevalence of antimicrobial resistance has become a global health problem. Acinetobacter baumannii is an important nosocomial pathogen due to its capacity to persist in the hospital environment. It has a high mortality rate and few treatment options. Antibiotic combinations can help to fight multi-drug resistant (MDR) bacterial infections, but they are rarely used in the clinics and mostly unexplored. The interaction between bacteriostatic and bactericidal antibiotics are mostly reported as antagonism based on the results obtained in the susceptible model laboratory strain Escherichia coli. However, in the present study, we report a synergistic interaction between nalidixic acid and tetracycline against clinical multi-drug resistant A. baumannii and E. coli. Here we provide mechanistic insight into this dichotomy. The synergistic combination was studied by checkerboard assay and time-kill curve analysis. We also elucidate the mechanism behind this synergy using several techniques such as fluorescence spectroscopy, flow cytometry, fluorescence microscopy, morphometric analysis, and real-time polymerase chain reaction. Nalidixic acid and tetracycline combination displayed synergy against most of the MDR clinical isolates of A. baumannii and E. coli but not against susceptible isolates. Finally, we demonstrate that this combination is also effective in vivo in an A. baumannii/Caenorhabditis elegans infection model (p < 0.001)

Download Full-text

A Cronobacter turicensis O1 Antigen-Specific Monoclonal Antibody Inhibits Bacterial Motility and Entry into Epithelial Cells

Infection and Immunity ◽

10.1128/iai.02211-14 ◽

2014 ◽

Vol 83 (3) ◽

pp. 876-887 ◽

Cited By ~ 6

Author(s):

Kristina Schauer ◽

Angelika Lehner ◽

Richard Dietrich ◽

Ina Kleinsteuber ◽

Rocío Canals ◽

...

Keyword(s):

Monoclonal Antibody ◽

Epithelial Cells ◽

Foodborne Pathogen ◽

Antimicrobial Effect ◽

Infection Model ◽

Cell Agglutination ◽

Content Type ◽

O Antigen ◽

Lethal Infection ◽

Insight Into

Cronobacter turicensisis an opportunistic foodborne pathogen that can cause a rare but sometimes lethal infection in neonates. Little is known about the virulence mechanisms and intracellular lifestyle of this pathogen. In this study, we developed an IgG monoclonal antibody (MAb; MAb 2G4) that specifically recognizes the O1 antigen ofC. turicensiscells. The antilipopolysaccharide antibody bound predominantly monovalently to the O antigen and reduced bacterial growth without causing cell agglutination. Furthermore, binding of the antibody to the O1 antigen ofC. turicensiscells caused a significant reduction of the membrane potential which is required to energize flagellar rotation, accompanied by a decreased flagellum-based motility. These results indicate that binding of IgG to the O antigen ofC. turicensiscauses a direct antimicrobial effect. In addition, this feature of the antibody enabled new insight into the pathogenicity ofC. turicensis. In a tissue culture infection model, pretreatment ofC. turicensiswith MAb 2G4 showed no difference in adhesion to human epithelial cells, whereas invasion of bacteria into Caco-2 cells was significantly inhibited.

Download Full-text

Two Enteropathogenic Escherichia coli Type III Secreted Proteins, EspA and EspB, Are Virulence Factors

Journal of Experimental Medicine ◽

10.1084/jem.188.10.1907 ◽

1998 ◽

Vol 188 (10) ◽

pp. 1907-1916 ◽

Cited By ~ 91

Author(s):

Akio Abe ◽

Ursula Heczko ◽

Richard G. Hegele ◽

B. Brett Finlay

Keyword(s):

Escherichia Coli ◽

Virulence Factors ◽

Enterohemorrhagic Escherichia Coli ◽

Laser Scanning Microscopy ◽

Secreted Proteins ◽

Confocal Laser ◽

Infection Model ◽

Enteropathogenic Escherichia Coli ◽

Type Iii

Enteropathogenic Escherichia coli (EPEC) belongs to a family of related bacterial pathogens, including enterohemorrhagic Escherichia coli (EHEC) O157:H7 and other human and animal diarrheagenic pathogens that form attaching and effacing (A/E) lesions on host epithelial surfaces. Bacterial secreted Esp proteins and a type III secretion system are conserved among these pathogens and trigger host cell signal transduction pathways and cytoskeletal rearrangements, and mediate intimate bacterial adherence to epithelial cell surfaces in vitro. However, their role in pathogenesis is still unclear. To investigate the role of Esp proteins in disease, mutations in espA and espB were constructed in rabbit EPEC serotype O103 and infection characteristics were compared to that of the wild-type strain using histology, scanning and transmission electron microscopy, and confocal laser scanning microscopy in a weaned rabbit infection model. The virulence of EspA and EspB mutant strains was severely attenuated. Additionally, neither mutant strain formed A/E lesions, nor did either one cause cytoskeletal actin rearrangements beneath the attached bacteria in the rabbit intestine. Collectively, this study shows for the first time that the type III secreted proteins EspA and EspB are needed to form A/E lesions in vivo and are indeed virulence factors. It also confirms the role of A/E lesions in disease processes.

Download Full-text