scholarly journals Inhibition of Apoptosis by Escherichia coli K1 Is Accompanied by Increased Expression of BclXL and Blockade of Mitochondrial Cytochrome c Release in Macrophages

2004 ◽  
Vol 72 (10) ◽  
pp. 6012-6022 ◽  
Author(s):  
Sunil K. Sukumaran ◽  
Suresh K. Selvaraj ◽  
Nemani V. Prasadarao
Keyword(s):  
Escherichia Coli ◽  
Cell Lines ◽  
Defense Mechanisms ◽  
Mrna Level ◽  
Protein A ◽  
Gene Array ◽  
Macrophage Cell ◽  
Cytochrome C Release ◽  
E Coli ◽  
Monocytes And Macrophages

ABSTRACT Escherichia coli K1 survival in the blood is a critical step for the onset of meningitis in neonates. Therefore, the circulating bacteria are impelled to avoid host defense mechanisms by finding a niche to survive and multiply. Our recent studies have shown that E. coli K1 enters and survives in both monocytes and macrophages in the newborn rat model of meningitis as well as in macrophage cell lines. Here we demonstrate that E. coli K1 not only extends the survival of human and murine infected macrophage cell lines but also renders them resistant to apoptosis induced by staurosporine. Macrophages infected with wild-type E. coli expressing outer membrane protein A (OmpA), but not with OmpA− E. coli, are resistant to DNA fragmentation and phosphatidylserine exposure induced by staurosporine. Infection with OmpA+ E. coli induces the expression of BclXL, an antiapoptotic protein, both at the mRNA level as assessed by gene array analysis and at the protein level as evaluated by immunoblotting. OmpA− E. coli infection of macrophages induced the release of cytochrome c from mitochondria into the cytosol and the activation of caspases 3, 6, and 9, events that were significantly blocked in OmpA+ E. coli-infected macrophages. In addition, OmpA+ E. coli-infected cells were resistant to a decrease in the transmembrane potential of mitochondria induced by staurosporine as measured by the MitoCapture fluorescence technique. Complementation of OmpA− E. coli with a plasmid containing the ompA gene restored the ability of OmpA− E. coli to inhibit the apoptosis of infected macrophages, further demonstrating that E. coli OmpA expression is critical for inducing macrophage survival and thereby finding a safe haven for its growth.

scholarly journals Receptors That Inhibit Macrophage Activation: Mechanisms and Signals of Regulation and Tolerance

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Ranferi Ocaña-Guzman ◽  
Luis Vázquez-Bolaños ◽  
Isabel Sada-Ovalle
Keyword(s):  
Immune System ◽  
Cell Lines ◽  
Immune Tolerance ◽  
Defense Mechanisms ◽  
Macrophage Activation ◽  
Immunological Tolerance ◽  
Innate Defense ◽  
Activation Mechanisms ◽  
Monocytes And Macrophages ◽  
Inhibitory Molecules

A variety of receptors perform the function of attenuating or inhibiting activation of cells in which they are expressed. Examples of these kinds of receptors include TIM-3 and PD-1, among others that have been widely studied in cells of lymphoid origin and, though to a lesser degree, in other cell lines. Today, several studies describe the function of these molecules as part of the diverse mechanisms of immune tolerance that exist in the immune system. This review analyzes the function of some of these proteins in monocytes and macrophages and as well as their participation as inhibitory molecules or elements of immunological tolerance that also act in innate defense mechanisms. We chose the receptors TIM-3, PD-1, CD32b, and CD200R because these molecules have distinct functional characteristics that provide examples of the different regulating mechanisms in monocytes and macrophages.

scholarly journals Cooperative Immune Suppression by Escherichia coli and Shigella Effector Proteins

2018 ◽  
Vol 86 (4) ◽  
Author(s):  
Maarten F. de Jong ◽  
Neal M. Alto
Keyword(s):  
Escherichia Coli ◽  
Defense Mechanisms ◽  
Immune Defense ◽  
Effector Proteins ◽  
Innate Immune ◽  
Host Cells ◽  
Secretion Systems ◽  
Content Type ◽  
E Coli ◽  
Type Iii Secretion Systems

ABSTRACT The enteric attaching and effacing (A/E) pathogens enterohemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC) and the invasive pathogens enteroinvasive E. coli (EIEC) and Shigella encode type III secretion systems (T3SS) used to inject effector proteins into human host cells during infection. Among these are a group of effectors required for NF-κB-mediated host immune evasion. Recent studies have identified several effector proteins from A/E pathogens and EIEC/ Shigella that are involved in suppression of NF-κB and have uncovered their cellular and molecular functions. A novel mechanism among these effectors from both groups of pathogens is to coordinate effector function during infection. This cooperativity among effector proteins explains how bacterial pathogens are able to effectively suppress innate immune defense mechanisms in response to diverse classes of immune receptor signaling complexes (RSCs) stimulated during infection.

scholarly journals TmPGRP-SA regulates Antimicrobial Response to Bacteria and Fungi in the Fat Body and Gut of Tenebrio molitor

2020 ◽  
Vol 21 (6) ◽  
pp. 2113 ◽  
Author(s):  
Maryam Keshavarz ◽  
Yong Hun Jo ◽  
Tariku Tesfaye Edosa ◽  
Young Min Bae ◽  
Yeon Soo Han
Keyword(s):  
Escherichia Coli ◽  
Fat Body ◽  
Mrna Level ◽  
Tenebrio Molitor ◽  
Mortality Rates ◽  
E Coli ◽  
Peptidoglycan Recognition Protein ◽  
Recognition Protein ◽  
Bacteria And Fungi ◽  
Antimicrobial Immune Response

Antimicrobial immune response is mediated by a signal-transducing sensor, peptidoglycan recognition protein-SA (PGRP-SA), that can recognize non-self molecules. Although several studies have focused on the involvement of Drosophila PGRP-SA in antimicrobial peptide (AMP) expression in response to infections, studies on its role in Tenebrio molitor are lacking. Here, we present a functional analysis of T. molitor PGRP-SA (TmPGRP-SA). In the absence of microbes, TmPGRP-SA was highly expressed in the late-larval fat body, followed by hemocytes, and gut. Interestingly, following Escherichia coli, Staphylococcus aureus, and Candida albicans infections, the mRNA level of TmPGRP-SA was significantly upregulated in both the fat body and gut. TmPGRP-SA silencing had a significant effect on the mortality rates for all the microbes tested. Moreover, TmPGRP-SA is required for regulating the expression of eight AMP genes namely TmTenecin-1, -2, and -4; TmDefensin-1 and -2; TmColeoptericin-1; and TmAttacin-1b and -2 in the fat body in response to E. coli and S. aureus infections. TmPGRP-SA is essential for the transcription of TmTenecin-2, -4; TmDefensin-2; TmColeoptericin-1, -2; and TmAttacin-1a, -1b, and -2 in the gut upon E. coli and C. albicans infections. However, TmPGRP-SA does not regulate AMP expression in the hemocytes. Additionally, TmDorsal isoform X2, a downstream Toll transcription factor, was downregulated in TmPGRP-SA-silenced larval fat body following E. coli and S. aureus challenges, and in the gut following E. coli and C. albicans challenges.

scholarly journals Characterization of Multidrug-Resistant Escherichia coli Isolates from Animals Presenting at a University Veterinary Hospital

2011 ◽  
Vol 77 (20) ◽  
pp. 7104-7112 ◽  
Author(s):  
Maria Karczmarczyk ◽  
Yvonne Abbott ◽  
Ciara Walsh ◽  
Nola Leonard ◽  
Séamus Fanning
Keyword(s):  
Escherichia Coli ◽  
Molecular Mechanisms ◽  
Gene Array ◽  
Multidrug Resistant ◽  
Genetic Determinants ◽  
Gene Encoding ◽  
Content Type ◽  
E Coli ◽  
Class 1

ABSTRACTIn this study, we examined molecular mechanisms associated with multidrug resistance (MDR) in a collection ofEscherichia coliisolates recovered from hospitalized animals in Ireland. PCR and DNA sequencing were used to identify genes associated with resistance. Class 1 integrons were prevalent (94.6%) and contained gene cassettes recognized previously and implicated mainly in resistance to aminoglycosides, β-lactams, and trimethoprim (aadA1,dfrA1-aadA1,dfrA17-aadA5,dfrA12-orfF-aadA2,blaOXA-30-aadA1,aacC1-orf1-orf2-aadA1,dfr7). Class 2 integrons (13.5%) contained thedfrA1-sat1-aadA1gene array. The most frequently occurring phenotypes included resistance to ampicillin (97.3%), chloramphenicol (75.4%), florfenicol (40.5%), gentamicin (54%), neomycin (43.2%), streptomycin (97.3%), sulfonamide (98.6%), and tetracycline (100%). The associated resistance determinants detected includedblaTEM,cat,floR,aadB,aphA1,strA-strB,sul2, andtet(B), respectively. TheblaCTX-M-2gene, encoding an extended-spectrum β-lactamase (ESβL), andblaCMY-2, encoding an AmpC-like enzyme, were identified in 8 and 18 isolates, respectively. The mobility of the resistance genes was demonstrated using conjugation assays with a representative selection of isolates. High-molecular-weight plasmids were found to be responsible for resistance to multiple antimicrobial compounds. The study demonstrated that animal-associated commensalE. coliisolates possess a diverse repertoire of transferable genetic determinants. Emergence of ESβLs and AmpC-like enzymes is particularly significant. To our knowledge, theblaCTX-M-2gene has not previously been reported in Ireland.

scholarly journals Interactions of uroseptic Escherichia coli with renal (A-498) and gastrointestinal (HT-29) cell lines

2014 ◽  
Vol 63 (12) ◽  
pp. 1575-1583 ◽  
Author(s):  
Tara L. Vollmerhausen ◽  
Jasmine L. Woods ◽  
Joan Faoagali ◽  
Mohammad Katouli
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Cell Lines ◽  
Genetic Relatedness ◽  
Gi Tract ◽  
E Coli ◽  
Initial Comparison ◽  
Culture Models ◽  
Cell Culture Models ◽  
Ht 29

We investigated the ability of Escherichia coli isolated from septic patients with urinary tract infection (UTI) to translocate through the gastrointestinal (GI) tract of the same patients using cell-culture models. Forty-seven hospitalized patients with urosepsis were included in this study. E. coli was isolated from their urine and blood (total 94 isolates) and investigated for genetic relatedness and interaction with the cell lines A-498 and HT-29. An initial comparison of the strains isolated from urine and blood showed that 44 out of 47 patients (94 %) had identical strains in their blood and urine. The blood isolates adhered to both cell lines, although their rate of adherence to A-498 cells was significantly higher than that to HT-29 cells (5.8±3.8 per cell vs 2.8±1.9; P<0.0001). The rate of translocation in A-498 cells was also significantly higher after 120 min (8.7×105 vs 2.9×105; P = 0.0006). Three non-identical blood isolates were unable to translocate in HT-29 cells, indicating that host immune factors might be more important than bacterial ability to translocate the GI epithelium in these patients. Our data showed that blood isolates from uroseptic patients are able to adhere to and translocate through both cell lines. This suggests that E. coli in patients with UTI may translocate from either the GI tract or the urinary tract, hence questioning the assumption that the urinary tract is the only source of septicaemia in these patients.

scholarly journals Adhesion of Human and Animal Escherichia coli Strains in Association with Their Virulence-Associated Genes and Phylogenetic Origins

2013 ◽  
Vol 79 (19) ◽  
pp. 5814-5829 ◽  
Author(s):  
Ulrike Frömmel ◽  
Werner Lehmann ◽  
Stefan Rödiger ◽  
Alexander Böhm ◽  
Jörg Nitschke ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Lines ◽  
Roe Deer ◽  
Correlated Data ◽  
Screening Tools ◽  
Screening Methods ◽  
Adhesion Assay ◽  
Intestinal Colonization ◽  
Content Type ◽  
E Coli

ABSTRACTIntestinal colonization is influenced by the ability of the bacterium to inhabit a niche, which is based on the expression of colonization factors.Escherichia colicarries a broad range of virulence-associated genes (VAGs) which contribute to intestinal (inVAGs) and extraintestinal (exVAGs) infection. Moreover, initial evidence indicates that inVAGs and exVAGs support intestinal colonization. We developed new screening tools to genotypically and phenotypically characterizeE. coliisolates originating in humans, domestic pigs, and 17 wild mammal and avian species. We analyzed 317 isolates for the occurrence of 44 VAGs using a novel multiplex PCR microbead assay (MPMA) and for adhesion to four epithelial cell lines using a new adhesion assay. We correlated data for the definition of new adhesion genes. inVAGs were identified only sporadically, particularly in roe deer (Capreolus capreolus) and the European hedgehog (Erinaceus europaeus). The prevalence of exVAGs depended on isolation from a specific host. Human uropathogenicE. coliisolates carried exVAGs with the highest prevalence, followed by badger (Meles meles) and roe deer isolates. Adhesion was found to be very diverse. Adhesion was specific to cells, host, and tissue, though it was also unspecific. Occurrence of the following VAGs was associated with a higher rate of adhesion to one or more cell lines:afa-dra,daaD,tsh,vat,ibeA,fyuA,mat,sfa-foc,malX,pic,irp2, andpapC. In summary, we established new screening methods which enabled us to characterize large numbers ofE. coliisolates. We defined reservoirs for potential pathogenicE. coli. We also identified a very broad range of colonization strategies and defined potential new adhesion genes.

scholarly journals Cytocidal and Apoptotic Effects of the ClyA Protein from Escherichia coli on Primary and Cultured Monocytes and Macrophages

2000 ◽  
Vol 68 (7) ◽  
pp. 4363-4367 ◽  
Author(s):  
Xin-He Lai ◽  
Ignacio Arencibia ◽  
Anders Johansson ◽  
Sun Nyunt Wai ◽  
Jan Oscarsson ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
E Coli ◽  
Monocytes And Macrophages ◽  
K 12 ◽  
Apoptotic Effects

ABSTRACT Cytolysin A (ClyA) is a newly discovered cytolytic protein ofEscherichia coli K-12 that mediates a hemolytic phenotype. We show here that highly purified ClyA and ClyA-expressing E. coli were cytotoxic and apoptogenic to fresh as well as cultured human and murine monocytes/macrophages.

scholarly journals Development of Transgenic Escherichia coli with Improved Viability by Heterologous Expression of a Heat Shock Protein Gene from Carrot (Daucus carota L.)

HortScience ◽  
2016 ◽  
Vol 51 (3) ◽  
pp. 305-310 ◽  
Author(s):  
Hanseul Park ◽  
Yeh-Jin Ahn
Keyword(s):  
Escherichia Coli ◽  
Heat Shock ◽  
Heat Shock Protein ◽  
Cell Viability ◽  
Cell Lines ◽  
Daucus Carota ◽  
Protein Gene ◽  
Control Cell ◽  
E Coli ◽  
Control Cell Line

A small heat shock protein gene from carrot (Daucus carota L.), Hsp17.7, was inserted into the Escherichia coli chromosome by RecE/RecT-based homologous recombination to increase cell viability during industrial fermentation, which frequently encounters adverse growth conditions. DNA construct “lipoprotein (Lpp) gene promoter—Hsp17.7 gene—flippase recombination target (Frt) cassette” flanked by the sequences of the insertion site of the E. coli chromosome (yddE pseudogene) was generated by polymerase chain reaction (PCR). The transformed E. coli cell lines that heterologously expressed Hsp17.7 exhibited shorter lag phase, compared with control cell line under normal (37 °C), heat (45 °C), and antifoam conditions. Cell viability was higher in the transformed cell lines in the heat (50 °C, up to 2-fold) and cold (2 °C, up to 1.7-fold) conditions. The soluble protein levels were also higher in the transformed E. coli cell lines by up to 20%, compared with control cell line in both stress conditions. The stress-tolerant transgenic cell lines developed in this study can contribute to more efficient and cost saving industrial cultivation of E. coli, which is most frequently used for recombinant protein production.

Effect of Trans-Cinnamaldehyde on preformed biofilm and biofilm formation of Escherichia coli isolated from urine specimens

QJM ◽  
2021 ◽  
Vol 114 (Supplement_1) ◽  
Author(s):  
Eman Adel El-Haddad ◽  
Soha Abdel Rahman El-Hady ◽  
Amira Esmail Abdel Hamid ◽  
Hisham Abdel Majeed Fahim
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Defense Mechanisms ◽  
Colorimetric Assay ◽  
Biofilm Inhibition ◽  
Hospital Acquired Infection ◽  
E Coli ◽  
Before And After ◽  
Tract Infections ◽  
Hospital Acquired

Abstract Introduction Bacteria in most environments exist as communities of sessile cells in a selfproduced polymeric matrix known as biofilms. Biofilms are responsible for more than 80% of infections, including urinary tract infections (UTI). UTI is the most common hospital acquired infection, caused mainly by Escherichia coli (E.coli). E. coli can readily form biofilm in such infections, specially in the presence of indwelling urinary catheter. It’s difficult to eradicate bacteria in biofilms, since they are shielded from the host defense mechanisms as phagocytes and antibodies, as well as antibiotics. Searching for alternative or adjuvant substances for prevention and eradication of biofilm associated infections are therefore urgently needed. Aim of the work Studying the efficacy of the trans-cinnamaldehyde (TC) for preventing E. coli biofilm formation. Materials and methods Thirty isolates of E.coli were obtained from urine samples. To test the effect of TC on E.coli biofilm formation and preformed biofilms, microtitre plates (MTP) were inoculated with the isolated E.coli and were treated with different concentrations of TC and incubated at 37° C. A colorimetric assay was used to assess biofilm inhibition and inactivation and optical densities (OD) were compared before and after adding different TC concentrations. Results The mean OD of the isolated E.coli biofilms was 1.3 and significantly decreased when mixed with TC different concentrations. TC had high activity in inhibition of preformed E.coli biofilms, where no biofilm was detected on MTP treated with 1.25% and 1.5% TC. Conclusion TC inhibited the biofilm forming ability of E.coli isolates could fully inactivate formed biofilms, suggesting its possibility to be used as an anti-biofilm agent or adjuvant in preventing and treating UTI caused by biofilm producing E.coli.

scholarly journals Cloning and Expression of the Escherichia coli K1 Outer Membrane Protein A Receptor, a gp96 Homologue

2003 ◽  
Vol 71 (4) ◽  
pp. 1680-1688 ◽  
Author(s):  
Nemani V. Prasadarao ◽  
Pramod K. Srivastava ◽  
Rajyalakshmi S. Rudrabhatla ◽  
Kwang Sik Kim ◽  
Sheng-he Huang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Protein A ◽  
Tumor Rejection ◽  
Cloning And Expression ◽  
Cdna Expression Library ◽  
E Coli ◽  
Outer Membrane Protein A

ABSTRACT Escherichia coli is one of the most common gram-negative bacteria that cause meningitis in neonates. Our previous studies have shown that outer membrane protein A (OmpA) of E. coli interacts with a 95-kDa human brain microvascular endothelial cell (HBMEC) glycoprotein, Ecgp, for invasion. Here, we report the identification of a gene that encodes Ecgp by screening of an HBMEC cDNA expression library as well as by 5′ rapid amplification of cDNA ends. The sequence of the Ecgp gene shows that it is highly similar to gp96, a tumor rejection antigen-1, and contains an endoplasmic reticulum retention signal, KDEL. Overexpression of either Ecgp or gp96 in both HBMECs and CHO cells increases E. coli binding and invasion. We further show that Ecgp gene-transfected HBMECs express Ecgp on the cell surface despite the presence of the KDEL motif. Northern blot analysis of total RNA from various eukaryotic cells indicates that Ecgp is significantly expressed in HBMECs. Recombinant His-tagged Ecgp blocked E. coli invasion efficiently by binding directly to the bacteria. These results suggest that OmpA of E. coli K1 interacts with a gp96-like molecule on HBMECs for invasion.

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