scholarly journals SslE (YghJ), a Cell-Associated and Secreted Lipoprotein of Neonatal Septicemic Escherichia coli, Induces Toll-Like Receptor 2-Dependent Macrophage Activation and Proinflammation through NF-κB and MAP Kinase Signaling

2018 ◽  
Vol 86 (9) ◽  
Author(s):  
Rima Tapader ◽  
Dipro Bose ◽  
Pujarini Dutta ◽  
Santasabuj Das ◽  
Amit Pal
Keyword(s):  
Escherichia Coli ◽  
Immune Response ◽  
Map Kinase ◽  
Macrophage Activation ◽  
Toll Like Receptor ◽  
Content Type ◽  
E Coli ◽  
Murine Macrophages ◽  
A Cell ◽  
Toll Like Receptor 2

ABSTRACT SslE (YghJ), a cell surface-associated and secreted lipoprotein, was identified as a potential vaccine candidate for extraintestinal pathogenic Escherichia coli, providing nearly complete protection from sepsis in a mouse model. We earlier found that SslE from neonatal septicemic E. coli could trigger the secretion of various proinflammatory cytokines in murine macrophages, the signaling pathway of which is still obscure. In this study, we showed that SslE specifically binds to Toll-like receptor 2 (TLR2)/TLR1 heterodimers and recruits downstream adaptors MyD88, TIRAP, and TRAF6. In addition, SslE stimulates nuclear translocation of NF-κB and activates different mitogen-activated protein (MAP) kinase signaling cascades specific to the secretion of each cytokine in murine macrophages, which becomes impaired in TLR2 small interfering RNA (siRNA)-transfected cells and in cells blocked with a monoclonal antibody (MAb) against TLR2, suggesting the involvement of TLR2 in NF-κB and MAP kinase activation and subsequent cytokine secretion. Furthermore, our study is the first to show that SslE can stimulate TLR2-dependent production of other proinflammatory hallmarks, such as reactive nitrogen and oxygen species as well as type 1 chemokines, which contribute to the anti-infection immune response of the host. Also, the overexpression of major histocompatibility complex class II (MHC II) and other costimulatory molecules (CD80 and CD86) in macrophages essentially indicates that SslE promotes macrophage activation and M1 polarization, which are crucial in framing the host's innate immune response to this protein, and hence, SslE could be a potent immunotherapeutic target against E. coli sepsis.

scholarly journals Signaling by Toll-Like Receptor 2 and 4 Agonists Results in Differential Gene Expression in Murine Macrophages

2001 ◽  
Vol 69 (3) ◽  
pp. 1477-1482 ◽  
Author(s):  
Matthew Hirschfeld ◽  
Janis J. Weis ◽  
Vladimir Toshchakov ◽  
Cindy A. Salkowski ◽  
M. Joshua Cody ◽  
...  
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Periodontal Pathogen ◽  
Agonist Activity ◽  
Toll Like Receptor ◽  
Inflammatory Gene Expression ◽  
Murine Macrophages ◽  
Tlr4 Agonist ◽  
Differential Gene ◽  
Toll Like Receptor 2

ABSTRACT Lipopolysaccharide (LPS) derived from the periodontal pathogenPorphyromonas gingivalis has been reported to differ structurally and functionally from enterobacterial LPS. These studies demonstrate that in contrast to protein-free enterobacterial LPS, a similarly purified preparation of P. gingivalis LPS exhibited potent Toll-like receptor 2 (TLR2), rather than TLR4, agonist activity to elicit gene expression and cytokine secretion in murine macrophages and transfectants. More importantly, TLR2 stimulation by this P. gingivalis LPS preparation resulted in differential expression of a panel of genes that are normally induced in murine macrophages by Escherichia coli LPS. These data suggest that (i) P. gingivalis LPS does not signal through TLR4 and (ii) signaling through TLR2 and through TLR4 differs quantitatively and qualitatively. Our data support the hypothesis that the shared signaling pathways elicited by TLR2 and by TLR4 agonists must diverge in order to account for the distinct patterns of inflammatory gene expression.

scholarly journals Escherichia coli Nissle 1917 Distinctively Modulates T-Cell Cycling and Expansion via Toll-Like Receptor 2 Signaling

2005 ◽  
Vol 73 (3) ◽  
pp. 1452-1465 ◽  
Author(s):  
Andreas Sturm ◽  
Klaus Rilling ◽  
Daniel C. Baumgart ◽  
Konstantinos Gargas ◽  
Tay Abou-Ghazalé ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Cycle ◽  
T Cells ◽  
T Cell ◽  
Peripheral Blood ◽  
Intestinal Inflammation ◽  
Toll Like Receptor ◽  
E Coli ◽  
Toll Like Receptor 2 ◽  
Cell Cycling

ABSTRACT Although the probiotic Escherichia coli strain Nissle 1917 has been proven to be efficacious for the treatment of inflammatory bowel diseases, the underlying mechanisms of action still remain elusive. The aim of the present study was to analyze the effects of E. coli Nissle 1917 on cell cycling and apoptosis of peripheral blood and lamina propria T cells (PBT and LPT, respectively). Anti-CD3-stimulated PBT and LPT were treated with E. coli Nissle 1917-conditioned medium (E. coli Nissle 1917-CM) or heat-inactivated E. coli Nissle 1917. Cyclin B1, DNA content, and caspase 3 expression were measured by flow cytometry to assess cell cycle kinetics and apoptosis. Protein levels of several cell cycle and apoptosis modulators were determined by immunoblotting, and cytokine profiles were determined by cytometric bead array. E. coli Nissle 1917-CM inhibits cell cycling and expansion of peripheral blood but not mucosal T cells. Bacterial lipoproteins mimicked the effect of E. coli Nissle 1917-CM; in contrast, heat-inactivated E. coli Nissle 1917, lipopolysaccharide, or CpG DNA did not alter PBT cell cycling. E. coli Nissle 1917-CM decreased cyclin D2, B1, and retinoblastoma protein expression, contributing to the reduction of T-cell proliferation. E. coli Nissle 1917 significantly inhibited the expression of interleukin-2 (IL-2), tumor necrosis factor α, and gamma interferon but increased IL-10 production in PBT. Using Toll-like receptor 2 (TLR-2) knockout mice, we further demonstrate that the inhibition of PBT proliferation by E. coli Nissle 1917-CM is TLR-2 dependent. The differential reaction of circulating and tissue-bound T cells towards E. coli Nissle 1917 may explain the beneficial effect of E. coli Nissle 1917 in intestinal inflammation. E. coli Nissle 1917 may downregulate the expansion of newly recruited T cells into the mucosa and limit intestinal inflammation, while already activated tissue-bound T cells may eliminate deleterious antigens in order to maintain immunological homeostasis.

scholarly journals Toll-Like Receptor 4/Stem Cell Antigen 1 Signaling Promotes Hematopoietic Precursor Cell Commitment to Granulocyte Development during the Granulopoietic Response to Escherichia coli Bacteremia

2013 ◽  
Vol 81 (6) ◽  
pp. 2197-2205 ◽  
Author(s):  
Xin Shi ◽  
Robert W. Siggins ◽  
William L. Stanford ◽  
John N. Melvan ◽  
Marc D. Basson ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Bone Marrow ◽  
Stem Cell ◽  
Precursor Cell ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Content Type ◽  
E Coli ◽  
Hematopoietic Precursor

ABSTRACTIn response to severe bacterial infection, bone marrow hematopoietic activity shifts toward promoting granulopoiesis. The underlying cell signaling mechanisms remain obscure. To study the role of Toll-like receptor 4 (TLR4)/stem cell antigen-1 (Sca-1) signaling in this process, bacteremia was induced in mice by intravenous injection ofEscherichia coli. A subgroup of animals also received intravenous 5-bromo-2-deoxyuridine (BrdU). In a separate set of experiments, bone marrow lineage-negative (lin−) stem cell growth factor receptor-positive (c-kit+) Sca-1−cells containing primarily common myeloid progenitors were culturedin vitrowithout or withE. colilipopolysaccharide (LPS). In genotypic background control mice, bacteremia significantly upregulated Sca-1 expression by lin−c-kit+cells, as reflected by a marked increase in BrdU-negative lin−c-kit+Sca-1+cells in the bone marrow. In mice with the TLR4 gene deletion, this bacteremia-evoked Sca-1 response was blocked.In vitro, LPS induced a dose-dependent increase in Sca-1 expression by cultured marrow lin−c-kit+Sca-1−cells. LPS-induced upregulation of Sca-1 expression was regulated at the transcriptional level. Inhibition of c-Jun N-terminal kinase/stress-activated protein kinase (JNK) activity with the specific inhibitor SP600125 suppressed LPS-induced upregulation of Sca-1 expression by marrow lin−c-kit+Sca-1−cells. Engagement of Sca-1 with anti-Sca-1 antibodies enhanced the expression of Sfpi1 spleen focus-forming virus (SFFV) proviral integration 1 (PU.1) in marrow lin−c-kit+Sca-1−cells cultured with LPS. Sca-1 null mice failed to maintain the marrow pool of granulopoietic cells following bacteremia. These results demonstrate that TLR4/Sca-1 signaling plays an important role in the regulation of hematopoietic precursor cell programming and their enhancement of granulocyte lineage commitment in response toE. colibacteremia.

scholarly journals Toll-Like Receptor 2 and Mincle Cooperatively Sense Corynebacterial Cell Wall Glycolipids

2017 ◽  
Vol 85 (7) ◽  
Author(s):  
Judith Schick ◽  
Philipp Etschel ◽  
Rebeca Bailo ◽  
Lisa Ott ◽  
Apoorva Bhatt ◽  
...  
Keyword(s):  
Cell Wall ◽  
Macrophage Activation ◽  
Invasive Disease ◽  
Mycolic Acid ◽  
Toll Like Receptor ◽  
Gamma Chain ◽  
Content Type ◽  
Lectin Receptor ◽  
Toll Like Receptor 2

ABSTRACT Nontoxigenic Corynebacterium diphtheriae and Corynebacterium ulcerans cause invasive disease in humans and animals. Host sensing of corynebacteria is largely uncharacterized, albeit the recognition of lipoglycans by Toll-like receptor 2 (TLR2) appears to be important for macrophage activation by corynebacteria. The members of the order Corynebacterineae (e.g., mycobacteria, nocardia, and rhodococci) share a glycolipid-rich cell wall dominated by mycolic acids (termed corynomycolic acids in corynebacteria). The mycolic acid-containing cord factor of mycobacteria, trehalose dimycolate, activates the C-type lectin receptor (CLR) Mincle. Here, we show that glycolipid extracts from the cell walls of several pathogenic and nonpathogenic Corynebacterium strains directly bound to recombinant Mincle in vitro. Macrophages deficient in Mincle or its adapter protein Fc receptor gamma chain (FcRγ) produced severely reduced amounts of granulocyte colony-stimulating factor (G-CSF) and of nitric oxide (NO) upon challenge with corynebacterial glycolipids. Consistently, cell wall extracts of a particular C. diphtheriae strain (DSM43989) lacking mycolic acid esters neither bound Mincle nor activated macrophages. Furthermore, TLR2 but not TLR4 was critical for sensing of cell wall extracts and whole corynebacteria. The upregulation of Mincle expression upon encountering corynebacteria required TLR2. Thus, macrophage activation by the corynebacterial cell wall relies on TLR2-driven robust Mincle expression and the cooperative action of both receptors.

scholarly journals Chlamydial MreB Directs Cell Division and Peptidoglycan Synthesis in Escherichia coli in the Absence of FtsZ Activity

mBio ◽  
2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Dev K. Ranjit ◽  
George W. Liechti ◽  
Anthony T. Maurelli
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Morphological Changes ◽  
Content Type ◽  
E Coli ◽  
Obligate Intracellular ◽  
Peptidoglycan Synthesis ◽  
Division Site ◽  
A Cell ◽  
Cell Division Protein

ABSTRACT Cell division is the ultimate process for the propagation of bacteria, and FtsZ is an essential protein used by nearly all bacteria for this function. Chlamydiae belong to a small group of bacteria that lack the universal cell division protein FtsZ but still divide by binary fission. Chlamydial MreB is a member of the shape-determining MreB/Mbl family of proteins responsible for rod shape morphology in Escherichia coli. Chlamydia also encodes a homolog of RodZ, an MreB assembly cytoskeletal protein that links MreB to cell wall synthesis proteins. We hypothesized that MreB directs cell division in Chlamydia and that chlamydial MreB could replace FtsZ function for cell division in E. coli. Overexpression of chlamydial mreB-rodZ in E. coli induced prominent morphological changes with production of large swollen or oval bacteria, eventually resulting in bacterial lysis. Low-level expression of chlamydial mreB-rodZ restored viability of a lethal ΔmreB mutation in E. coli, although the bacteria lost their typical rod shape and grew as rounded cells. When FtsZ activity was inhibited by overexpression of SulA in the ΔmreB mutant of E. coli complemented with chlamydial mreB-rodZ, spherical E. coli grew and divided. Localization studies using a fluorescent fusion chlamydial MreB protein indicated that chlamydial RodZ directs chlamydial MreB to the E. coli division septum. These results demonstrate that chlamydial MreB, in partnership with chlamydial RodZ, acts as a cell division protein. Our findings suggest that an mreB-rodZ-based mechanism allows Chlamydia to divide without the universal division protein FtsZ. IMPORTANCE The study of Chlamydia growth and cell division is complicated by its obligate intracellular nature and biphasic lifestyle. Chlamydia also lacks the universal division protein FtsZ. We employed the cell division system of Escherichia coli as a surrogate to identify chlamydial cell division proteins. We demonstrate that chlamydial MreB, together with chlamydial RodZ, forms a cell division and growth complex that can replace FtsZ activity and support cell division in E. coli. Chlamydial RodZ plays a major role in directing chlamydial MreB localization to the cell division site. It is likely that the evolution of chlamydial MreB and RodZ to form a functional cell division complex allowed Chlamydia to dispense with its FtsZ-based cell division machinery during genome reduction. Thus, MreB-RodZ represents a possible mechanism for cell division in other bacteria lacking FtsZ.

scholarly journals Rapid Bladder Interleukin-10 Synthesis in Response to Uropathogenic Escherichia coli Is Part of a Defense Strategy Triggered by the Major Bacterial Flagellar Filament FliC and Contingent on TLR5

mSphere ◽  
2019 ◽  
Vol 4 (6) ◽  
Author(s):  
Dhruba Acharya ◽  
Matthew J. Sullivan ◽  
Benjamin L. Duell ◽  
Kelvin G. K. Goh ◽  
Lahiru Katupitiya ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Immune Response ◽  
Urinary Tract Infection ◽  
Immune System ◽  
Urinary Tract ◽  
Interleukin 10 ◽  
Innate Immune ◽  
Content Type ◽  
E Coli ◽  
Flagellar Filament

ABSTRACT Urinary tract infection (UTI) caused by uropathogenic Escherichia coli (UPEC) engages interleukin-10 (IL-10) as an early innate immune response to regulate inflammation and promote the control of bladder infection. However, the mechanism of engagement of innate immunity by UPEC that leads to elicitation of IL-10 in the bladder is unknown. Here, we identify the major UPEC flagellar filament, FliC, as a key bacterial component sensed by the bladder innate immune system responsible for the induction of IL-10 synthesis. IL-10 responses of human as well as mouse bladder epithelial cell-monocyte cocultures were triggered by flagella of three major UPEC representative strains, CFT073, UTI89, and EC958. FliC purified to homogeneity induced IL-10 in vitro and in vivo as well as other functionally related cytokines, including IL-6. The genome-wide innate immunological context of FliC-induced IL-10 in the bladder was defined using RNA sequencing that revealed a network of transcriptional and antibacterial defenses comprising 1,400 genes that were induced by FliC. Of the FliC-responsive bladder transcriptome, altered expression of il10 and 808 additional genes were dependent on Toll-like receptor 5 (TLR5), according to analysis of TLR5-deficient mice. Examination of the potential of FliC and associated innate immune signature in the bladder to boost host defense, based on prophylactic or therapeutic administration to mice, revealed significant benefits for the control of UPEC. We conclude that detection of FliC through TLR5 triggers rapid IL-10 synthesis in the bladder, and FliC represents a potential immune modulator that might offer benefit for the treatment or prevention of UPEC UTI. IMPORTANCE Interleukin-10 is part of the immune response to urinary tract infection (UTI) due to E. coli, and it is important in the early control of infection in the bladder. Defining the mechanism of engagement of the immune system by the bacteria that enables the protective IL-10 response is critical to exploring how we might exploit this mechanism for new infection control strategies. In this study, we reveal part of the bacterial flagellar apparatus (FliC) is an important component that is sensed by and responsible for induction of IL-10 in the response to UPEC. We show this response occurs in a TLR5-dependent manner. Using infection prevention and control trials in mice infected with E. coli, this study also provides evidence that purified FliC might be of value in novel approaches for the treatment of UTI or in preventing infection by exploiting the FliC-triggered bladder transcriptome.

scholarly journals Effect of Heat-Killed Escherichia coli, Lipopolysaccharide, and Muramyl Dipeptide Treatments on the Immune Response Phenotype and Allergy in Neonatal Pigs Sensitized to the Egg White Protein Ovomucoid

2012 ◽  
Vol 19 (12) ◽  
pp. 1955-1964 ◽  
Author(s):  
Julie Schmied ◽  
Prithy Rupa ◽  
Sarah Garvie ◽  
Bruce Wilkie
Keyword(s):  
Escherichia Coli ◽  
Immune Response ◽  
Clinical Signs ◽  
Muramyl Dipeptide ◽  
Egg White ◽  
Content Type ◽  
E Coli ◽  
Neonatal Pigs

ABSTRACTPredisposition to food allergies may reflect a type 2 immune response (IR) bias in neonates due to the intrauterine environment required to maintain pregnancy. The hygiene hypothesis states that lack of early environmental stimulus leading to inappropriate development and bias in IR may also contribute. Here, the ability of heat-killedEscherichia coli, lipopolysaccharide (LPS), or muramyl dipeptide (MDP) to alter IR bias and subsequent allergic response in neonatal pigs was investigated. Three groups of three litters of pigs (12 pigs/litter) were given intramuscular injections ofE. coli, LPS, MDP, or phosphate-buffered saline (PBS) (control) and subsequently sensitized to the egg white allergen ovomucoid using an established protocol. To evaluate change in IR bias, immunoglobulin isotype-associated antibody activity (AbA), concentrations of type 1 and 2 and proinflammatory cytokines released from mitogen-stimulated blood mononuclear cells, and the percentage of T-regulatory cells (T-regs) in blood were measured. Clinical signs of allergy were assessed after oral challenge with egg white. The greatest effect on IR bias was observed in MDP-treated pigs, which had a type 2-biased phenotype by isotype-specific AbA, cytokine production, and a low proportion of T-regs. LPS-treated pigs had decreased type 1- and type 2-associated AbA.E. coli-treated pigs displayed increased response to Ovm as AbA and had more balanced cytokine profiles, as well as the highest proportion of T-regs. Accordingly, pigs treated with MDP were more susceptible to allergy than PBS controls, while pigs treated with LPS were less susceptible. Treatment withE. colidid not significantly alter the frequency of clinical signs.

scholarly journals Development of a Method To Produce Hemoglobin in a Bioreactor Culture of Escherichia coli BL21(DE3) Transformed with a Plasmid Containing Plesiomonas shigelloides Heme Transport Genes and Modified Human Hemoglobin Genes

2011 ◽  
Vol 77 (18) ◽  
pp. 6703-6705 ◽  
Author(s):  
B. J. Z. Smith ◽  
P. Gutierrez ◽  
E. Guerrero ◽  
C. J. Brewer ◽  
D. P. Henderson
Keyword(s):  
Escherichia Coli ◽  
Dry Weight ◽  
Bioreactor Culture ◽  
Human Hemoglobin ◽  
Plesiomonas Shigelloides ◽  
Content Type ◽  
E Coli ◽  
Escherichia Coli Bl21 ◽  
Heme Transport ◽  
A Cell

ABSTRACTWe describe a method for production of recombinant human hemoglobin byEscherichia coligrown in a bioreactor.E. coliBL21(DE3) transformed with a plasmid containing hemoglobin genes andPlesiomonas shigelloidesheme transport genes reached a cell dry weight of 83.64 g/liter and produced 11.92 g/liter of hemoglobin in clarified lysates.

Sign in / Sign up

Export Citation Format

Share Document