globotriaosylceramide and Hemolytic-Uremic-Syndrome

Topics: Animals; CRISPR-Cas Systems; Escherichia coli Infections; Hemolytic-Uremic Syndrome; Host-Pathogen Interactions; Humans; Immunotoxins; Models, Molecular; Neoplasms; Protein Conformation; Shiga Toxins; Shiga-Toxigenic Escherichia coli; Structure-Activity Relationship; Trihexosylceramides

The leading cause of hemolytic uremic syndrome (HUS) in children is Shiga toxin-producing Escherichia coli (STEC) infection, which has a major outbreak potential. Since the early 2010s, STEC epidemiology is characterized by a decline of the historically predominant O157 serogroup and the emergence of non-O157 STEC, especially O26 and O80 in France. STEC contamination occurs through the ingestion of contaminated food or water, person-to-person transmission, or contact with ruminants or their contaminated environment. The main symptom is diarrhea, which is bloody in about 60% of patients and occurs after a median incubation period of three days. Shiga toxins released by STEC induce a cascade of thrombogenic and inflammatory changes of microvascular endothelial cells. HUS is observed in 5-15% of STEC infection cases, defined by the triad of mechanical hemolytic anemia, thrombocytopenia, and acute renal injury. The diagnosis of STEC infection relies on biological screening for Shiga toxins and STEC in stools and serology. Treatment of STEC-HUS is mainly symptomatic, as no specific drug has proved effective. The effect of antibiotics in STEC infection and STEC-HUS remains debated; however, some bacteriostatic antibiotics might have a beneficial effect. Proofs of evidence of a benefit from complement blockade therapy in STEC-HUS are also lacking. Clinical and bacteriological STEC-HUS surveillance needs to be continued. Ongoing prospective studies will document the role of bacteriostatic antibiotics in STEC infection and STEC-HUS, and of complement blockade therapy in STEC-HUS.

Topics: Adult; Animals; Anti-Bacterial Agents; Antibodies, Monoclonal, Humanized; Blood Transfusion; Child, Preschool; Combined Modality Therapy; Complement Pathway, Alternative; Contraindications, Drug; Diarrhea; Disease Outbreaks; Endothelium, Vascular; Environmental Exposure; Escherichia coli Infections; Feces; France; Hemolytic-Uremic Syndrome; Humans; Infant; Plasma Exchange; Prognosis; Shiga Toxin; Shiga-Toxigenic Escherichia coli; Trihexosylceramides; Zoonoses

Topics: Brain; Endothelial Cells; Enterohemorrhagic Escherichia coli; Escherichia coli Infections; Globosides; Hemolytic-Uremic Syndrome; Host-Pathogen Interactions; Humans; Kidney; Primary Cell Culture; Shiga Toxin 1; Shiga Toxin 2; Trihexosylceramides

Shiga toxins consist of an A-moiety and five B-moieties able to bind the neutral glycosphingolipid globotriaosylceramide (Gb3) on the cell surface. To intoxicate cells efficiently, the toxin A-moiety has to be cleaved by furin and transported retrogradely to the Golgi apparatus and to the endoplasmic reticulum. The enzymatically active part of the A-moiety is then translocated to the cytosol, where it inhibits protein synthesis and in some cell types induces apoptosis. Protection of cells can be provided either by inhibiting binding of the toxin to cells or by interfering with any of the subsequent steps required for its toxic effect. In this article we provide a brief overview of the interaction of Shiga toxins with cells, describe some compounds and conditions found to protect cells against Shiga toxins, and discuss whether they might also provide protection in animals and humans.

Topics: Animals; Antidotes; Apoptosis; Bacterial Proteins; Dysentery, Bacillary; Hemolytic-Uremic Syndrome; Host-Pathogen Interactions; Humans; Protein Biosynthesis; Protein Conformation; Protein Transport; Shiga Toxins; Shiga-Toxigenic Escherichia coli; Shigella dysenteriae; Structure-Activity Relationship; Trihexosylceramides

Infection with Shiga toxin (Stx)-producing Escherichia coli (STEC), including O157:H7, causes bloody diarrhea and hemorrhagic colitis in humans, occasionally resulting in fatal systemic complications, such as neurological damage and hemolytic-uremic syndrome. Because Stx is a major virulence factor of the infectious disease, a series of Shiga toxin neutralizers with various structural characteristics has been developed as promising therapeutic agents. Most of these agents function to bind to the toxin directly and inhibit the binding to its receptor present on the target cells. Other neutralizers do not inhibit receptor binding but induce aberrant intracellular transport of the toxin, resulting in effective detoxification. Such a novel type of Stx neutralizer provides a new therapeutic strategy against STEC infections. Here, recent progress of the development of Stx neutralizers is reviewed.

Topics: Animals; Anti-Bacterial Agents; Binding Sites; Combinatorial Chemistry Techniques; Drug Design; Endoplasmic Reticulum; Escherichia coli Infections; Escherichia coli O157; Globosides; Hemolytic-Uremic Syndrome; Humans; Macrophages, Peritoneal; Mice; Peptides; Polymers; Rabbits; Serum Amyloid P-Component; Shiga Toxin 1; Shiga Toxin 2; Silanes; Trihexosylceramides; Trisaccharides; Virulence Factors

The glycosphingolipid globotriaosyl ceramide, (Galalpha1-4Galss1-4 glucosyl ceramide-Gb(3)) also known as CD77 and the P(k) blood group antigen, is bound by both verotoxins and by the HIV adhesin, gp120. Gb(3) plays an important receptor role in VT induced hemolytic uremic syndrome (HUS) and HIV infection. The organization of glycolipids, including Gb(3), into lipid rafts is central to both pathologies. The fatty acid heterogeneity within the Gb(3) lipid moiety plays a central role in assembly within such ordered domains. Differential binding of verotoxins and gp120 to such Gb(3) isoforms in model and cell membranes indicates a significant role in the eventual pathogenic outcome. HUS may provide the first example whereby membrane Gb(3) organization provides a predictor for tissue selective in vivo pathology.

Topics: Animals; Cell Membrane Structures; Glycosphingolipids; Hemolytic-Uremic Syndrome; HIV Envelope Protein gp120; HIV Infections; Humans; Membrane Microdomains; Receptors, Cell Surface; Shiga Toxins; Trihexosylceramides

Shiga toxin (Stx)-producing enterohemorrhagic Escherichia coli O157:H7 has become a global threat to public health, as a primary cause of a worldwide spread of hemorrhagic colitis complicated by diarrhea-associated hemolytic uremic syndrome (HUS), a disorder of thrombocytopenia, microangiopathic hemolytic anemia, and acute renal failure that mainly affects early childhood. Endothelial dysfunction has been recognized as the trigger event in the development of microangiopathic processes. Endothelial cells, mainly those located in the renal microvasculature, are primary targets of the toxic effects of Stx1 and 2. Stxs bound to their specific globotriaosylceramide (Gb3Cer) receptor on the cell surface trigger a cascade of signaling events, involving NF-κB activation, that induce expression of genes encoding for adhesion molecules and chemokines, and culminate in the adhesion of leukocytes to endothelial cells, thereby increasing the endothelial susceptibility to leukocyte-mediated injury. Activated endothelial cells in response to Stxs lose the normal thromboresistance phenotype and become thrombogenic, initiating microvascular thrombus formation. Evidence is emerging that complement activation in response to Stxs favors platelet thrombus formation on endothelial cells, which may play a role in amplifying the inflammation-thrombosis circuit in Stx-associated HUS.

Topics: Acute Kidney Injury; Capillaries; Chemokines; Child, Preschool; Endothelial Cells; Endothelium, Vascular; Escherichia coli O157; Hemolytic-Uremic Syndrome; Humans; Leukocytes; Models, Biological; NF-kappa B; Shiga Toxin; Trihexosylceramides

Shiga toxin (Stx)-producing Escherichia coli (STEC) cause an enteric illness that results in a spectrum of outcomes ranging from asymptomatic carriage to uncomplicated diarrhea, bloody diarrhea, and the postdiarrheal haemolytic uremic syndrome (HUS), which leads to renal and other organ microvascular thrombosis. Binding of Stx to the glycosphingolipid (GSL) globotriaosylceramide (Gb3Cer/CD77) on endothelial cells followed by receptor-mediated endocytosis is the linchpin in STEC-mediated disease. Only GSLs that associate strongly with lipid rafts appear to carry Stxs retrogradely from the plasma membrane through the Golgi apparatus to the endoplasmic reticulum where they are translocated to the cytosol and exert their toxic function. Thus, the biophysical features of the lipid moiety of GSL receptors may influence its incorporation into certain membrane domains and thereby affect toxin destination. Consequently, a detailed structural analysis of Stx-binding GSLs is required to illuminate the molecular causes that may underlie the different Stx susceptibilities of endothelial cells derived from various vascular beds. Solid phase overlay binding assays of thin-layer chromatography (TLC)-separated GSL preparations employing specific antibodies and/or Stxs in conjunction with anti-Stx-antibodies are commonly used for the identification of Stx-binding GSLs. Such GSL-profiling combined with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) represents a convenient strategy to structurally characterize Stx-receptors from any biological sources such as primary cells, cell lines, or organs. This approach may be helpful to gain insights into Stx-induced impairment of target cells that is suggested to originate at least partly from the structural heterogeneity of the cellular ligands of Stxs.

Topics: Amino Acid Sequence; Animals; Chromatography, Thin Layer; Endocytosis; Endothelium, Vascular; Escherichia coli Infections; Hemolytic-Uremic Syndrome; Humans; Ligands; Membrane Microdomains; Molecular Sequence Data; Peptide Mapping; Protein Conformation; Protein Subunits; Protein Transport; Proteomics; Shiga Toxins; Shiga-Toxigenic Escherichia coli; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Structure-Activity Relationship; Trihexosylceramides

Shiga toxins(Stxs), which are produced by enterohemorrhagic Escherichia coli and Shigella dysenteriae serotype I, induce proinflammatory cytokines including tumor necrosis factor-alpha, interleukin(IL)-1 beta, IL-6, interferon-gamma, and chemokines such as IL-8 in intestinal epithelial cells, vascular endothelial cells, and monocytes/macrophages in vitro and in kidneys and spleen in vivo. Cytokines induced by Stxs and lipopolysaccharide enhance the toxicity of Stxs via up-regulation of the expression of Gb3, a Stx receptor, and infiltration of neutrophils. Stxs bind to neutrophils and transmigrate across intestinal mucosa and are transported to the target organs through bloodstreams. Stxs induce cytokines in vascular endothelial cells and peripheral blood monocytes and may injure organ tissues, finally resulting in hemolytic uremic syndrome and encephalopathia.

Topics: Animals; Cytokines; Hemolytic-Uremic Syndrome; Humans; Intestinal Mucosa; Neutrophils; Shiga Toxin; Trihexosylceramides; Up-Regulation

Shiga toxin(Stx) produced by enterohemorrhagic E. coli is the virulence factor that causes not only enterohemorrhagic colitis but also fatal complications, such as hemolytic uremic syndrome. To prevent the complications, new strategies targeted to Stx have been tested, mostly using mimics of the trisaccharide structure of neutral lipid Gb3, the receptor for Stx. One group of such new drugs are agents that can bind to Stx in gastrointestinal tract and prevent its spread to extraintestinal sites, and the other group are water-soluble neutralizers that suppress Stx cytotoxicity in the circulation. Although most of these are now under the laboratory investigations, one of these drugs may hopefully be utilized clinically to prevent hemolytic uremic syndrome in future.

Topics: Drug Design; Escherichia coli O157; Hemolytic-Uremic Syndrome; Humans; Oligosaccharides; Organosilicon Compounds; Shiga Toxin; Toxoids; Trihexosylceramides; Trisaccharides

Eukaryotic cell surface glycolipids can act as both the primary interface between bacteria and their host and secondly as a targeting mechanism for bacterial virulence factors. The former is characterized by redundancy in adhesin-receptor interactions and the latter by a higher affinity, more restrictive glycolipid binding specificity for targeting. Interactions of verotoxin with its glycolipid receptor globotriaosylceramide and Helicobacter pylori binding to a variety of different glycolipids, which can be environmentally regulated, provide examples of these differing modes of glycolipid receptor function. Verotoxins are involved in endothelial targeting in the microangiopathies of hemorrhagic colitis and hemolytic uremic syndrome (HUS). The highly restricted binding specificity and crystal structure of the verotoxin B subunit have allowed theoretical modeling of the Gb3 binding site of the verotoxin B subunit pentamer which provides an approach to intervention. Studies of the role of glycolipid function in verotoxin-induced disease have concentrated on the distribution of Gb3 and its ability to mediate the internalization of the toxin within the target cell. The distribution of Gb3 within the renal glomerulus plays a central role in defining the age-related etiology of HUS following gastrointestinal infection with VT producing Escherichia coli. H. pylori, on the other hand, instigates a less distinct but more complex disseminated gastric inflammation. Studies on the role of glycolipid receptors in H. pylori infection have been bogged down in establishing the importance of each binding specificity defined. In addition, the physiological condition of the organism within the various binding assays has not been extensively considered, such that spurious non-physiological interactions may have been elucidated. The identification and cloning of a Le(b) binding adhesin and the identification of cell surface hsp70 as a mediator of sulfoglycolipid binding under stress conditions may now allow a more molecular approach to define the role of glycolipid recognition in this infection.

Topics: Adhesins, Bacterial; Age Factors; Animals; Bacterial Toxins; Binding Sites; Escherichia coli Infections; Gastrointestinal Diseases; Helicobacter Infections; Helicobacter pylori; Hemolytic-Uremic Syndrome; Humans; Hydrogen-Ion Concentration; Kidney Glomerulus; Receptors, Cell Surface; Shiga Toxin 1; Stomach; Stress, Physiological; Trihexosylceramides

The hemolytic uremic syndrome (HUS) is the end result of a variety of etiologic agents that can induce endothelial cell injury and thrombotic microangiopathy (TMA) mostly within the kidney. The typical, post-diarrheal verocytotoxin associated HUS (D + HUS) is the major cause of acute renal failure in children worldwide. In the course of HUS treatment, fluid overload is usually the result of overhydration in the context of oliguria or anuria which cause edema, hypertension, worsening of neurologic signs and cardiac failure. Appropriate and timely use of dialysis has dramatically reduced complications of renal failure and extra-renal complications are now the main causes of mortality and morbidity in D + HUS. The reasons for treatment by infusion of fresh frozen plasma and/or plasmapheresis for D + HUS are theoretical and their therapeutic effects are inconclusive. We believe that plasma administration for regular D + HUS has no value and is potentially harmful. Until new strategies become available in clinical practice, the general consensus for the moment is that careful supportive management with patience is still the most appropriate form of D + HUS therapy.

Topics: Escherichia coli Infections; Escherichia coli O157; Hemolytic-Uremic Syndrome; Humans; Immunoglobulins, Intravenous; Oligosaccharides; Plasma; Plasmapheresis; Renal Dialysis; Trihexosylceramides

Hemolytic uremic syndrome (HUS) is caused by endothelial cell damages. Ninety percent of children with HUS have verotoxin-producing E.coli infection. Verotoxin binds to glycolipid receptors globotriaosyl ceramide (Gb3), and the difference of Gb3 expression level in each organ would lead to specific organ involvement. The receptors are expressed in human renal cortex and medulla. The expression level of Gb3 in normal human brain has not been characterized completely. However involvement of central nervous system is a severe complication of HUS. Spreading of microvascular thrombosis caused by combined effects of lipopolysaccharide, cytokine, enhanced shear stress, and verotoxin would play a major role in the development of central nervous dysfunction.

Topics: Bacterial Toxins; Central Nervous System Diseases; Escherichia coli Infections; Escherichia coli O157; Gastrointestinal Hemorrhage; Hemolytic-Uremic Syndrome; Humans; Purpura, Thrombotic Thrombocytopenic; Shiga Toxin 1; Trihexosylceramides

Topics: Bacterial Toxins; Base Sequence; Carbohydrate Sequence; Disease Models, Animal; Dysentery, Bacillary; Endocytosis; Enterotoxins; Escherichia coli; Gastrointestinal Hemorrhage; Gene Expression Regulation, Bacterial; Genes, Bacterial; Hemolytic-Uremic Syndrome; Humans; Molecular Sequence Data; Protein Biosynthesis; Receptors, Cell Surface; Shiga Toxin 1; Shiga Toxin 2; Shiga Toxins; Shigella; Structure-Activity Relationship; Trihexosylceramides; Virulence

Topics: Animals; Cell Survival; Chlorocebus aethiops; Epithelial Cells; Escherichia coli Infections; Globosides; Hemolytic-Uremic Syndrome; Humans; Kidney Cortex; Membrane Microdomains; Primary Cell Culture; Protein Binding; Shiga Toxin 1; Shiga Toxin 2; Shiga-Toxigenic Escherichia coli; Trihexosylceramides; Vero Cells

Shiga toxin (Stx) produced by enterohemorrhagic

Topics: Animals; Brain Diseases; Cytokines; Disease Models, Animal; Enterohemorrhagic Escherichia coli; Escherichia coli Infections; Heat-Shock Response; Hemolytic-Uremic Syndrome; Inflammation; Lipopolysaccharides; Macrophages; Microglia; Rats; Rats, Wistar; Shiga Toxin 2; Trihexosylceramides

Hemolytic uremic syndrome (HUS) and acute encephalopathy caused by enterohemorrhagic Escherichia coli infection occur commonly in children, whereas adult-onset disease is rare. Here we report the case of a 24-year-old woman who developed acute encephalopathy and recovered without sequelae. She initially developed abdominal pain and diarrhea. On day 6, O-157 Shiga toxin was detected in her stool and she developed HUS. On day 11, acute encephalopathy developed and she required artificial ventilation. She was treated with steroid pulse therapy and plasma exchange (PE) and then discharged on day 53 without any sequelae. Globotriaosylceramide, a Shiga toxin receptor, is more frequently present on the cellular membranes of women than on those of men. Therefore, it is conceivable that adult women are at a higher risk of developing acute encephalopathy than men. Steroid pulse therapy and PE may effectively treat acute encephalopathy by reducing inflammatory cytokine levels in the blood; therefore, these treatments should be proactively considered.

Topics: Acute Disease; Antigens, Tumor-Associated, Carbohydrate; Brain Diseases; Enterohemorrhagic Escherichia coli; Escherichia coli Infections; Female; Hemolytic-Uremic Syndrome; Humans; Methylprednisolone; Plasma Exchange; Prednisolone; Pulse Therapy, Drug; Risk; Shiga Toxin; Treatment Outcome; Trihexosylceramides; Young Adult

The life-threatening sequela of hemorrhagic colitis induced by Shiga toxins (Stx)-producing Escherichia coli (STEC) infections in humans is hemolytic uremic syndrome (HUS), the main cause of acute renal failure in early childhood. The key step in the pathogenesis of HUS is the appearance of Stx in the blood of infected patients because these powerful virulence factors are capable of inducing severe microangiopathic lesions in the kidney. During precocious toxemia, which occurs in patients before the onset of HUS during the intestinal phase, Stx bind to several different circulating cells. An early response of these cells might include the release of proinflammatory mediators associated with the development of HUS. Here, we show that primary human monocytes stimulated with Shiga toxin 1a (Stx1a) through the glycolipid receptor globotriaosylceramide released larger amounts of proinflammatory molecules (IL-1β, TNFα, IL-6, G-CSF, CXCL8, CCL2, CCL4) than Stx1a-treated neutrophils. The mediators (except IL-1β) are among the top six proinflammatory mediators found in the sera from patients with HUS in different studies. The molecules appear to be involved in different pathogenetic steps of HUS, i.e. sensitization of renal endothelial cells to the toxin actions (IL-1β, TNFα), activation of circulating monocytes and neutrophils (CXCL8, CCL2, CCL4) and increase in neutrophil counts in patients with poor prognosis (G-CSF). Hence, a role of circulating monocytes in the very early phases of the pathogenetic process culminating with HUS can be envisaged. Impairment of the events of precocious toxemia would prevent or reduce the risk of HUS in STEC-infected children.

Topics: Cells, Cultured; Cytokines; Hemolytic-Uremic Syndrome; Humans; Interleukin-8; Monocytes; Neutrophils; Shiga Toxin 1; Shiga-Toxigenic Escherichia coli; Trihexosylceramides

Shiga-toxin-producing Escherichia coli (STEC) infections usually cause haemolytic uraemic syndrome (HUS) equally in male and female children. This study investigated the localization of globotriaosylceramide (Gb3) in human brain and kidney tissues removed from forensic autopsy cases in Japan. A fatal case was used as a positive control in an outbreak of diarrhoeal disease caused by STEC O157:H7 in a kindergarten in Urawa in 1990. Positive immunodetection of Gb3 was significantly more frequent in female than in male distal and collecting renal tubules. To correlate this finding with a clinical outcome, a retrospective analysis of the predictors of renal failure in the 162 patients of two outbreaks in Japan was performed: one in Tochigi in 2002 and the other in Kagawa Prefecture in 2005. This study concludes renal failure, including HUS, was significantly associated with female sex, and the odds ratio was 4·06 compared to male patients in the two outbreaks. From 2006 to 2009 in Japan, the risk factor of HUS associated with STEC infection was analysed. The number of males and females and the proportion of females who developed HUS were calculated by age and year from 2006 to 2009. In 2006, 2007 and 2009 in adults aged >20 years, adult women were significantly more at risk of developing HUS in Japan.

Topics: Adolescent; Adult; Age Factors; Aged; Aged, 80 and over; Brain; Child; Child, Preschool; Diarrhea; Disease Outbreaks; Escherichia coli Infections; Female; Hemolytic-Uremic Syndrome; Humans; Infant; Infant, Newborn; Japan; Kidney; Male; Middle Aged; Renal Insufficiency; Retrospective Studies; Risk Factors; Sex Factors; Shiga-Toxigenic Escherichia coli; Trihexosylceramides; Young Adult

In 2011, a large outbreak of Shiga toxin-producing enterohemorrhagic Escherichia coli (EHEC) infections occurred in northern Germany, which mainly affected adults. Out of 3842 patients, 104 experienced a complicated course comprising hemolytic uremic syndrome and neurological complications, including cognitive impairment, aphasia, seizures and coma. T2 hyperintensities on magnet resonance imaging (MRI) bilateral in the thalami and in the dorsal pons were found suggestive of a metabolic toxic effect. Five of the 104 patients died because of toxic heart failure. In the present study, the post-mortem neuropathological findings of the five EHEC patients are described. Histological investigation of 13 brain regions (frontal, temporal, occipital cortex, corpora mammillaria, thalamus, frontal operculum, corona radiata, gyrus angularis, pons, medulla oblongata, cerebellar vermis and cerebellar hemisphere) showed no thrombosis, ischemic changes or fresh infarctions. Further, no changes were found in electron microscopy. In comparison with five age-matched controls, slightly increased activation of microglia and a higher neuronal expression of interleukin-1β and of Shiga toxin receptor CD77/globotriaosylceramide 3 was observed. The findings were confirmed by Western blot analyses. It is suggested that CD77/globotriaosylceramide upregulation may be a consequence to Shiga toxin exposure, whereas increased interleukin-1β expression may point to activation of inflammatory cascades.

Topics: Aged; Aged, 80 and over; Brain; Cognition Disorders; Encephalitis; Enterohemorrhagic Escherichia coli; Escherichia coli Infections; Female; Hemolytic-Uremic Syndrome; Humans; Interleukin-1beta; Male; Trihexosylceramides; Up-Regulation

Shiga toxin (Stx)-producing Escherichia coli (STEC) cause hemolytic uremic syndrome (HUS). This study investigated whether Stx2 induces hemolysis and whether complement is involved in the hemolytic process. RBCs and/or RBC-derived microvesicles from patients with STEC-HUS (n = 25) were investigated for the presence of C3 and C9 by flow cytometry. Patients exhibited increased C3 deposition on RBCs compared with controls (p < 0.001), as well as high levels of C3- and C9-bearing RBC-derived microvesicles during the acute phase, which decreased after recovery. Stx2 bound to P1 (k) and P2 (k) phenotype RBCs, expressing high levels of the P(k) Ag (globotriaosylceramide), the known Stx receptor. Stx2 induced the release of hemoglobin and lactate dehydrogenase in whole blood, indicating hemolysis. Stx2-induced hemolysis was not demonstrated in the absence of plasma and was inhibited by heat inactivation, as well as by the terminal complement pathway Ab eculizumab, the purinergic P2 receptor antagonist suramin, and EDTA. In the presence of whole blood or plasma/serum, Stx2 induced the release of RBC-derived microvesicles coated with C5b-9, a process that was inhibited by EDTA, in the absence of factor B, and by purinergic P2 receptor antagonists. Thus, complement-coated RBC-derived microvesicles are elevated in HUS patients and induced in vitro by incubation of RBCs with Stx2, which also induced hemolysis. The role of complement in Stx2-mediated hemolysis was demonstrated by its occurrence only in the presence of plasma and its abrogation by heat inactivation, EDTA, and eculizumab. Complement activation on RBCs could play a role in the hemolytic process occurring during STEC-HUS.

Topics: Adult; Aged; Antibodies, Monoclonal, Humanized; Child; Child, Preschool; Coated Vesicles; Complement Activation; Complement C3; Complement C9; Complement Membrane Attack Complex; Edetic Acid; Erythrocytes; Escherichia coli Infections; Escherichia coli O157; Female; Gene Expression; Hemolysis; Hemolytic-Uremic Syndrome; Humans; Infant; L-Lactate Dehydrogenase; Male; Middle Aged; Purinergic P2 Receptor Antagonists; Receptors, Purinergic P2; Shiga Toxin; Suramin; Trihexosylceramides

Hemolytic uremic syndrome (HUS) caused by intestinal Shiga toxin-producing Escherichia coli infections is a worldwide health problem, as dramatically exemplified by the German outbreak occurred in summer 2011 and by a constant burden of cases in children. Shiga toxins (Stx) play a pivotal role in HUS by triggering endothelial damage in kidney and brain through globotriaosylceramide (Gb3Cer) receptor targeting. Moreover, Stx interact with human neutrophils, as experimentally demonstrated in vitro and as observed in patients with HUS. A neutrophil-protective role on endothelial damage (sequestration of circulating toxins) and a causative role in toxin delivery from the gut to the kidney (piggyback transport) have been suggested in different studies. However, the receptor that recognizes Stx in human neutrophils, which do not express Gb3Cer, has not been identified. In this study, by competition and functional experiments with appropriate agonists and antagonists (LPS, anti-TLR4 Abs, respectively), we have identified TLR4 as the receptor that specifically recognizes Stx1 and Stx2 in human neutrophils. Accordingly, these treatments displaced both toxin variants from neutrophils and, upon challenge with Stx1 or Stx2, neutrophils displayed the same pattern of cytokine expression as in response to LPS (assessed by quantitative RT-PCR, ELISA, or multiplexed Luminex-based immunoassays). Moreover, data were supported by adequate controls excluding any potential interference of contaminating LPS in Stx-binding and activation of neutrophils. The identification of the Stx-receptor on neutrophils provides additional elements to foster the understanding of the pathophysiology of HUS and could have an important effect on the development of therapeutic strategies.

Topics: Antibodies, Monoclonal; Cytokines; Escherichia coli; Escherichia coli Infections; Hemolytic-Uremic Syndrome; Humans; Lipopolysaccharides; Neutrophils; Shiga Toxin 1; Shiga Toxin 2; Toll-Like Receptor 4; Trihexosylceramides

Postdiarrhea hemolytic uremic syndrome is the most common cause of acute renal failure in children in Argentina. Renal damage has been strongly associated with Shiga toxin (Stx), which binds to the globotriaosylceramide (Gb3) receptor on the plasma membrane of target cells. The purpose of the study was to evaluate the in vivo effects of C-9, a potent inhibitor of glucosylceramide synthase and Gb3 synthesis, on kidney and colon in an experimental model of hemolytic uremic syndrome in rats. Rats were i.p. injected with supernatant from recombinant Escherichia coli expressing Stx2 (sStx2). A group of these rats were orally treated with C-9 during 6 d, from 2 d prior until 4 d after sStx2 injection. The injection of sStx2 caused renal damage as well as a loss of goblet cells in colonic mucosa. Oral treatment with C-9 significantly decreased rat mortality to 50% and reduced the extension of renal and intestinal injuries in the surviving rats. The C-9 also decreased Gb3 and glucosylceramide expression levels in rat kidneys. It is particularly interesting that an improvement was seen when C-9 was administered 2 d before challenge, which makes it potentially useful for prophylaxis.

Topics: Administration, Oral; Animals; Biomarkers; Colon; Creatinine; Dioxanes; Disease Models, Animal; Enzyme Inhibitors; Glucosyltransferases; Hemolytic-Uremic Syndrome; Intestinal Mucosa; Kidney; Male; Pyrrolidines; Rats; Rats, Sprague-Dawley; Shiga Toxin 2; Time Factors; Trihexosylceramides; Urea

Diarrhea-associated hemolytic uremic syndrome (D(+)HUS) is caused by the ingestion of Escherichia coli that produce Shiga toxin (Stx), which is composed of a cytotoxic A subunit and pentameric B subunits that bind globotriaosylceramide on susceptible cells. Stx occurs in 2 types, Stx1 and Stx2. B subunits of either type stimulate von Willebrand factor (VWF) secretion from human umbilical vein endothelial cells (HUVECs), and Stx2B can cause thrombotic microangiopathy in Adamts13(-/-) mice. We have now determined that Stx1B and Stx2B activate different signaling pathways in HUVECs. VWF secretion induced by Stx1B is associated with a transient rise in intracellular Ca(2+) level that is blocked by chelation with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester, removal of extracellular Ca(2+), the phospholipase C inhibitor U73122, the protein kinase inhibitor staurosporine, or small interfering RNA knockdown of protein kinase Cα. In contrast, Stx2B-induced VWF secretion is associated with activation of protein kinase A (PKA) and is blocked by the PKA inhibitor H89 or small interfering RNA knockdown of PKA. Stx2B does not increase cAMP levels and may activate PKA by a cAMP-independent mechanism. The activation of distinct signaling pathways may be relevant to understanding why E coli that express Stx2 are more likely to cause D(+)HUS than are E coli expressing only Stx1.

Topics: Animals; Calcium; Cyclic AMP-Dependent Protein Kinases; Diarrhea; Egtazic Acid; Endothelial Cells; Escherichia coli; Escherichia coli Infections; Gene Silencing; Hemolytic-Uremic Syndrome; Humans; Mice; Protein Binding; Protein Kinase C-alpha; Protein Kinase Inhibitors; RNA, Small Interfering; Shiga Toxin 1; Shiga Toxin 2; Signal Transduction; Trihexosylceramides; Umbilical Veins; von Willebrand Factor

Verotoxin binding to its receptor, globotriaosyl ceramide(Gb(3)) mediates the glomerular pathology of hemolytic uremic syndrome, but Gb(3) is expressed in both tubular and glomerular cells. Gb(3) within detergent-resistant membranes, an index of glycolipid-cholesterol enriched lipid rafts, is required for in vitro cytotoxicity. We found that verotoxin 1 and 2 binding to human adult renal glomeruli is detergent resistant, whereas the strong verotoxin binding to renal tubules is detergent sensitive. Verotoxin binding to pediatric glomeruli was detergent resistant but binding to adult glomeruli was enhanced, remarkably for some samples, by detergent extraction. Detergent-sensitive glomerular components may provide age-related protection against verotoxin glomerular binding. Mouse glomeruli remained verotoxin unreactive after detergent extraction, whereas tubular binding was lost. Cholesterol extraction induced strong verotoxin binding in poorly reactive adult glomeruli, suggesting cholesterol can mask Gb(3) in glomerular lipid rafts. Binding of the human immunodeficiency virus (HIV) adhesin, gp120 (another Gb(3) ligand) was detergent sensitive, tubule-restricted, and inhibited by verotoxin B subunit pretreatment, and may relate to HIV nephropathy. Our study shows that differential membrane Gb(3) organization in glomeruli and tubules provides a basis for the age- and glomerular-restricted pathology of hemolytic uremic syndrome.

Topics: Age Factors; Animals; Cholesterol; Detergents; Hemolytic-Uremic Syndrome; HIV Envelope Protein gp120; Humans; Kidney Glomerulus; Kidney Tubules; Membrane Microdomains; Mice; Protein Binding; Protein Synthesis Inhibitors; Shiga Toxins; Trihexosylceramides

The glycosphingolipids globotrihexosylceramide (Gb3, CD77) and isoglobotrihexosylceramide (iGb3) are isomers differing only in one glycosidic bond and have been implicated in several processes of the innate and adaptive immune system.. 1) To verify the function of Gb3 in the pathogenesis of hemolytic-uremic syndrome as the cellular receptor responsible for cytotoxicity caused by verotoxin (VT) elaborated by Shigella and certain strains of E.coli. 2) To investigate in vivo the previously implicated function of iGb3 as the endogenous lipid ligand responsible for positive selection of invariant natural killer T-cells (iNKT), which have an essential regulatory function in infection, tumor rejection and tolerance.. Generation of mice deficient in Gb3 and iGb3 synthesizing enzymes and VT injection into Gb3-deficient mice. Analysis of iNKT cell development and function by flow cytometry and by administration of the exogenous agonist alpha-galactosylceramide in iGb3-deficient mice.. For 1) Gb3-deficient mice were insensitive to otherwise lethal doses of VT, and 2) iGb3-deficient mice showed normal numbers of iNKT cells. Furthermore the function of iNKT cells evolving in iGb3-deficient mice was unaffected.. 1) Gb3 is the cellular receptor mediating verotoxin cytotoxicity in haemolytic-uremic syndrome. 2) In contrast to previous indirect implications, iGb3 cannot be regarded as an endogenous ligand responsible for the positive selection of iNKT cells.

Topics: Animals; Cytokines; Dendritic Cells; Escherichia coli; Female; Globosides; Hemolytic-Uremic Syndrome; Lymphocyte Count; Mice; Mice, Knockout; Natural Killer T-Cells; Shiga Toxins; Shigella; Trihexosylceramides

Shiga toxin-producing Escherichia coli causes hemolytic uremic syndrome, a constellation of disorders that includes kidney failure and central nervous system dysfunction. Shiga toxin binds the amphipathic, membrane-bound glycolipid globotriaosylceramide (Gb(3)) and uses it to enter host cells and ultimately cause cell death. Thus, cell types that express Gb(3) in target tissues should be recognized. The objective of this study was to determine whether immunohistologic detection of Gb(3) was affected by the method of tissue preparation. Tissue preparation included variations in fixation (immersion or perfusion) and processing (paraffin or frozen) steps; paraffin processing employed different dehydration solvents (acetone or ethanol). Perfusion-fixation in combination with frozen sections or acetone-dehydrated tissue for paraffin sections resulted in specific recognition of Gb(3) using immunohistochemical or immunofluorescent methods. In the mouse tissues studied, Gb(3) was associated with tubules in the kidney and neurons in the nervous system. On the other hand, Gb(3) localization to endothelial cells was determined to be an artifact generated due to immersion-fixation or tissue dehydration with ethanol. This finding was corroborated by glycolipid profiles from tissue subjected to dehydration; namely Gb(3) was subject to extraction by ethanol more than acetone during tissue dehydration. The results of this study show that tissue preparation is crucial to the persistence and preservation of the glycolipid Gb(3) in mouse tissue. These methods may serve as a basis for determining the localization of other amphipathic glycolipids in tissue.

Topics: Animals; Antibodies, Monoclonal; Fluorescent Antibody Technique, Direct; Frozen Sections; Hemolytic-Uremic Syndrome; Kidney Tubules; Male; Mice; Mice, Inbred C57BL; Neurons; Paraffin Embedding; Shiga Toxins; Shiga-Toxigenic Escherichia coli; Trihexosylceramides

Enterohemorrhagic Escherichia coli (EHEC) produces Shiga toxin (Stx) and causes renal disease in humans. Dutch Belted (DB) rabbits naturally infected with EHEC O153 develop hemolytic-uremic syndrome-like disease. The aims of this study were to experimentally reproduce O153-induced renal disease in DB rabbits and investigate bacterial and host factors involved in pathogenesis. The pathogenicity of E. coli O157:H7 was also investigated in rabbits. The stx1AB region of O153 was sequenced. By use of liquid chromatography-tandem mass spectrometry, we identified homologs of the Stx receptor, globotriaosylceramide (Gb3), in rabbit kidney extracts. Infected rabbits developed clinical signs and intestinal and kidney lesions. Renal pathological changes consisted of intimal swelling, perivascular edema, erythrocyte fragmentation, capillary thickening, luminal constriction, leukocytic infiltration, mesangial deposits, and changes in Bowman's capsule and space. Sequence analysis of a approximately 7-kb region of the O153 chromosome indicated homology to the Stx1-producing bacteriophage H19B. Our findings indicate that DB rabbits are suitable for the study of the renal manifestations of EHEC infection in humans.

Topics: Animals; Bacteriophages; Caco-2 Cells; Cecum; Disease Models, Animal; DNA, Bacterial; Escherichia coli Infections; Escherichia coli O157; Feces; Female; Hemolytic-Uremic Syndrome; Humans; Kidney; Male; Molecular Sequence Data; Rabbits; Sequence Analysis; Shiga Toxin; Time Factors; Trihexosylceramides

Shiga toxin (Stx) produced by enterohemorrhagic Escherichia coli is a critical factor in the onset of hemolytic uremic syndrome. The current study was designed to assess whether n-3 and (or) n-6 polyunsaturated fatty acids (PUFA) act as a valuable adjunct to prevent the cell injury of renal tubule cells in the emergence of HUS. The target cells, ACHN cells derived from human tubule epithelium, were cultured with each PUFA, then exposed to Stx-1 or Stx-2. The rank order of potency of PUFA to inhibit the cell death caused by each toxin was as follows: EPA > AA = DHA >> LNA. There were dose-response relations in the efficacy of each PUFA. No prophylactic effect was found in the cultures with LA. Immunofluorescence assays revealed that both the expression of the toxin receptor on ACHN cells and binding between the toxin and cells were unaffected by the PUFA. These results suggest that EPA is the most efficacious PUFA against the renal tubule cell injury caused by Stx, which may be assigned to an alteration in the intracellular pathway leading to cell death.

Topics: Cell Line; Cell Survival; Dose-Response Relationship, Drug; Epithelial Cells; Escherichia coli; Fatty Acids, Omega-3; Fatty Acids, Omega-6; Fatty Acids, Unsaturated; Hemolytic-Uremic Syndrome; Humans; Kidney Tubules; Receptors, Cell Surface; Shiga Toxin; Shiga Toxin 1; Shiga Toxin 2; Trihexosylceramides

Kidney lesions similar to those in humans with hemolytic-uremic syndrome were observed histologically in 82 of 122 piglets inoculated intragastrically with Shiga-toxigenic Escherichia coli but not in 29 controls. The locations of lesions matched locations where Stx-2 binding and Gb3 (globotriasylceramide receptors for Stx) were identified immunohistochemically.

Topics: Animals; Animals, Newborn; Escherichia coli; Escherichia coli Infections; Hemolytic-Uremic Syndrome; Humans; Immunohistochemistry; Kidney; Retrospective Studies; Shiga Toxin 2; Swine; Trihexosylceramides

Topics: Animals; Anti-Bacterial Agents; Clinical Trials as Topic; Escherichia coli Infections; Escherichia coli O157; Hemolytic-Uremic Syndrome; Humans; Mice; Molecular Mimicry; Polymers; Receptors, Cell Surface; Trihexosylceramides

Shiga toxin (Stx) is a major virulence factor in infection with Stx-producing Escherichia coli (STEC). We developed a series of linear polymers of acrylamide, each with a different density of trisaccharide of globotriaosylceramide (Gb3), which is a receptor for Stx, and identified Gb3 polymers with highly clustered trisaccharides as Stx adsorbents functioning in the gut. The Gb3 polymers specifically bound to both Stx1 and Stx2 with high affinity and markedly inhibited the cytotoxic activities of these toxins. Oral administration of the Gb3 polymers protected mice after administration of a fatal dose of E. coli O157:H7, even when the polymers were administered after the infection had been established. In these mice, the serum level of Stx was markedly reduced and fatal brain damage was substantially suppressed, which suggests that the Gb3 polymers entrap Stx in the gut and prevent its entrance into the circulation. These results indicate that the Gb3 polymers can be used as oral therapeutic agents that function in the gut against STEC infections.

Topics: Acrylamide; Animals; Brain Chemistry; Carbohydrate Sequence; Disease Models, Animal; Dose-Response Relationship, Drug; Escherichia coli Infections; Escherichia coli O157; Female; Hemolytic-Uremic Syndrome; Mice; Mice, Inbred C57BL; Molecular Sequence Data; Polymers; Protein Binding; Receptors, Cell Surface; Shiga Toxin 1; Shiga Toxin 2; Shiga Toxins; Trihexosylceramides; Trisaccharides

Enterohemorrhagic Escherichia coli (EHEC) is the major cause of hemolyticuremic syndrome (HUS) characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure. EHEC produces one or more Shiga toxins (Stx1 and Stx2), and it was assumed that Stx's only relevant biologic activity was cell destruction through inhibition of protein synthesis. However, recent data indicate that in vivo the cytokine milieu may determine whether endothelial cells survive or undergo apoptosis/necrosis when exposed to Stxs. In this study, we analyzed the genome-wide expression patterns of human endothelial cells stimulated with subinhibitory concentrations of Stxs in order to characterize the genomic expression program involved in the vascular pathology of HUS. We found that Stxs elicited few, but reproducible, changes in gene expression. The majority of genes reported in this study encodes for chemokines and cytokines, which might contribute to the multifaceted inflammatory response of host endothelial cells observed in patients suffering from EHEC disease. In addition, our data provide for the first time molecular insights into the epidemiologically well-established higher pathogenicity of Stx2 over Stx1.

Topics: Apoptosis; Chemokines; Cytokines; DNA Primers; Endothelium, Vascular; Enzyme-Linked Immunosorbent Assay; Escherichia coli; Escherichia coli Infections; Flow Cytometry; Gene Expression Profiling; Gene Expression Regulation; Hemolytic-Uremic Syndrome; Humans; Immunohistochemistry; Receptors, Cell Surface; Shiga Toxins; Trihexosylceramides; Umbilical Veins

Both verotoxin (VT)1 and VT2 share the same receptor, globotriaosyl ceramide (Gb(3)). Although VT1 is slightly more cytotoxic in vitro and binds Gb(3) with higher affinity, VT2 is more toxic in mice and may be associated with greater pathology in human infections. In this study we have compared the biodistribution of iodine 125 ((125)I)-VT1 and (125)I-VT2 versus pathology in the mouse.. (125)I-VT1 whole-body autoradiography defined the tissues targeted. VT1 and VT2 tissue distribution, clearance, and tissue binding sites were compared. The effect of a soluble receptor analogue, adamantylGb(3), on VT2/Gb3 binding and in vivo pathology was assessed.. (125)I-VT1 autoradiography identified the lungs and nasal turbinates as major, previously unrecognized, targets, while kidney cortex and the bone marrow of the spine, long bones, and ribs were also significant targets. VT2 did not target the lung, but accumulated in the kidney to a greater extent than VT1. The serum half-life of VT1 was 2.7 minutes with 90% clearance at 5 minutes, while that of VT2 was 3.9 minutes with only 40% clearance at 5 minutes. The extensive binding of VT1, but not VT2, within the lung correlated with induced lung disease. Extensive hemorrhage into alveoli, edema, alveolitis and neutrophil margination was seen only after VT1 treatment. VT1 targeted lung capillary endothelial cells. Identical tissue binding sites (subsets of proximal/distal tubules and collecting ducts) for VT1 and VT2 were detected by toxin overlay of serial frozen kidney sections. Glucosuria was found to be a new marker of VT1- and VT2-induced renal pathology and positive predictor of outcome in the mouse, consistent with VT-staining of proximal tubules. Lung Gb3 migrated on thin-layer chromatography (TLC) faster than kidney Gb(3), suggesting a different lipid composition. AdamantylGb(3), a soluble Gb(3) analogue, competed effectively for Gb3 binding by VT1 and VT2 in vitro. However, the effect in the mouse model (only measured against VT2, due to the lower LD(50), a concentration required for 50% lethality) was to increase, rather than reduce, pathology and further reduce the VT2 serum clearance rate. Additional renal pathology was seen in VT2 + adamantylGb(3)-treated mice.. The lung is a preferential (Gb(3)) "sink" for VT1, which explains the relatively slower clearance of VT2 and subsequent increased VT2 renal targeting and VT2 mortality in this animal model.

Topics: Animals; Autoradiography; Disease Models, Animal; Female; Hemolytic-Uremic Syndrome; Iodine Radioisotopes; Kidney; Lung; Mice; Mice, Inbred BALB C; Radionuclide Imaging; Shiga Toxin 1; Shiga Toxin 2; Tissue Distribution; Trihexosylceramides

Specific hydroxy groups of the terminal disaccharide unit of globotriaosyl ceramide (Gb(3)Cer) were identified from binding studies with deoxyGb(3)Cer and verotoxins (VTs) [Nyholm, Magnusson, Zheng, Norel, Binnington-Boyd and Lingwood (1996) Chem. Biol. 3, 263-275]. Four such hydroxy groups (2", 4", 6" and 6') were each substituted with an amino group and the corresponding deoxyamino globotrioses were conjugated to a ceramide-like aglycone which contained an adamantyl group instead of an acyl chain. Such aglycone modification significantly enhanced the water-solubility of the glycoconjugates [Mylvaganam and Lingwood (1999) Biochem. Biophys. Res. Commun. 257, 391-394]. The inhibitory potential of these soluble aminodeoxy conjugates on the binding of VT(1) to Gb(3)Cer immobilized on an ELISA plate was evaluated. Only the 2" and the 6' deoxyamino conjugates were effective inhibitors (IC(50) 10 microM); the 4" and 6" conjugates were ineffective up to 10 mM. To evaluate the importance of incorporating a rigid adamantyl hydrocarbon group into the ceramide aglycone, globotriaose was conjugated to a t- butylacetamido or an adamantaneacetamido aglycone. By similar ELISAs, only the adamantaneacetamido conjugate inhibited the binding of VT(1) to Gb(3)Cer. When deoxyamino conjugates were adsorbed to silica on TLC plates, only the 2" and 6" conjugates bound VT(1) and VT(2). By a similar TLC assay, acetamido derivatives of 2" and 6' deoxyamino conjugates showed less binding to VT(1) and VT(2). Neither the crystallographically determined structure of the VT(1)-globotriaose complex nor modelling studies fully explain the binding patterns shown by these deoxyamino glycoconjugates. Enhanced solvation of the ammonium group of the deoxyamino conjugate could enforce greater constraints in the binding interactions.

Topics: Binding Sites; Chromatography, Thin Layer; Dose-Response Relationship, Drug; Enzyme-Linked Immunosorbent Assay; Glycolipids; Hemolytic-Uremic Syndrome; Humans; Inhibitory Concentration 50; Kidney; Models, Chemical; Models, Molecular; Oligosaccharides; Protein Structure, Tertiary; Shiga Toxins; Trihexosylceramides

Oral infection with enterohemorrhagic Escherichia coli (EHEC) may cause severe enteritis, followed in up to 10% of cases by an extraintestinal complication, the hemolytic uremic syndrome (HUS). HUS is characterized by a triad of symptoms: anemia, thrombocytopenia, and acute renalfailure due to thrombotic microangiopathy. EHEC produces several virulence factors, among which a family of phage-encoded cytotoxins, called Shiga toxin 1 and Shiga toxin 2, seems to be most important. However, since an appropriate animal model is not available, pathogenicity of these emerging enteric pathogens is still poorly understood. Germ-free gnotobiotic piglets infected orally with an O1577:H7 or an O26:H11 EHEC wild-type isolate, both producing Shiga toxin 2, developed intestinal and extraintestinal manifestations of EHEC disease, including thrombotic microangiopathy in the kidneys, the morphologic hallmark of HUS in humans. Thus, gnotobiotic piglets are suitable to further study the pathophysiology of EHEC-induced HUS. It can be expected that data obtainedfrom this animal model will improve our current standard of knowledge about this emerging infectious disease.

Topics: Animals; Child, Preschool; Digestive System; Disease Models, Animal; Endothelium, Vascular; Escherichia coli Infections; Escherichia coli O157; Female; Germ-Free Life; Hemolytic-Uremic Syndrome; Humans; Immunohistochemistry; Kidney; Microcirculation; Purpura, Thrombotic Thrombocytopenic; Shiga Toxin 2; Swine; Swine Diseases; Trihexosylceramides

The relationship between differential susceptibility to hemolytic-uremic syndrome (HUS) and levels of globotriaosylceramide (Gb3) in serum was studied in patients infected with verotoxin-producing Escherichia coli (VTEC). The serum Gb3 levels in patients with HUS were lower than these in diarrheal patients without subsequent HUS or in patients without clinical symptoms, indicating that individuals with a lower content of serum Gb3 show a higher incidence of HUS following VTEC infection.

Topics: Adolescent; Adult; Aged; Child; Child, Preschool; Diarrhea; Disease Susceptibility; Escherichia coli; Escherichia coli Infections; Female; Hemolytic-Uremic Syndrome; Humans; Male; Middle Aged; Shiga Toxins; Trihexosylceramides

Gastrointestinal disease caused by Shiga toxin-producing Escherichia coli (STEC) is frequently complicated by life-threatening toxin-induced systemic sequelae, including the hemolytic uremic syndrome. We previously constructed a recombinant bacterium displaying a Shiga toxin receptor mimic on its surface which neutralized Shiga toxins with very high efficiency. Moreover, oral administration of the live bacterium completely protected mice from challenge with virulent STEC. In this study, we investigated the protective capacity of formaldehyde-killed receptor mimic bacteria, as these are likely to be safer for administration to humans. The killed bacteria completely protected STEC-challenged mice when administered three times daily; incomplete protection was achieved using two doses per day. Commencement of therapy could be delayed for up to 48 h after challenge without diminishing protection, depending on the virulence of the challenge strain. Thus, administration of this agent early in the course of human STEC disease may prevent progression to life-threatening complications.

Topics: Administration, Oral; Animals; Escherichia coli; Escherichia coli Infections; Escherichia coli Vaccines; Formaldehyde; Hemolytic-Uremic Syndrome; Male; Mice; Mice, Inbred BALB C; Molecular Mimicry; Receptors, Cell Surface; Shiga Toxin; Trihexosylceramides; Vaccines, Inactivated; Vaccines, Synthetic

The effect of Shiga-like toxin 1 (Stx1) produced by Escherichia coli O157 on platelets was studied with an argon laser light-assisted shear-induced platelet aggregometer and with binding assays. Stx1 markedly enhanced the platelet aggregation under low shear stress but did not affect it under high shear stress. Minimal concentration of Stx1 required for the enhancement was 0.25 ng/ml, and almost maximal enhancement was observed at a final concentration of > or =2.5 ng/ml. This enhanced platelet aggregation disappeared after leukocyte depletion from normal platelet-rich plasma with a specific filter. In contrast, a standard platelet aggregometer was unable to detect this enhanced platelet aggregation in either the presence or the absence of ADP. 125I-labeled purified Stx1 did not specifically bind to normal washed platelets depleted of leukocytes, and thin-layer chromatographic analysis of glycolipids extracted from normal platelet lysates also confirmed that leukocyte-depleted normal platelets lack Stx1-specific receptor globotriaosylceramide (Gb3). Supernatant from the monocyte suspension stimulated with Stx1 exhibited the enhanced low shear stress induced platelet aggregation, but that from the polymorphonuclear cell suspension did not. Several cytokines produced from monocytes reproduced this event in vitro. Further, plasmas from six out of seven patients with hemolytic uremic syndrome (HUS) had activity similar to the purified Stx1. This activity was almost totally impaired after treatment of HUS plasmas with Gb3 in accord with reduction of plasma Stx1 levels. Taken together, these results indicate that platelets lack Gb3, and Stx1 appears to modulate platelet aggregation in an indirect fashion, presumably by the release of cytokines or chemical compounds from the target tissues.

Topics: Bacterial Toxins; Child; Child, Preschool; Cytokines; Escherichia coli O157; Female; Hemolytic-Uremic Syndrome; Humans; Lasers; Leukocytes; Male; Middle Aged; Nephelometry and Turbidimetry; Platelet Aggregation; Radioligand Assay; Shiga Toxin 1; Stress, Mechanical; Trihexosylceramides

The hemolytic uremic syndrome (HUS) is the most common cause of acute renal failure in children. The role of a verocytotoxin (VT)-producing Escherichia coli has been strongly implicated in the epidemic form of HUS. Although direct toxicity of VT on glomerular endothelial cells has been demonstrated, it remained still unclear how the VT is transported from the intestine to the target organs. In this study we demonstrate that VT, when incubated in whole blood, binds rapidly and completely to human polymorphonuclear leukocytes (PMNs) and not to other components of blood. Binding studies with (125)I-VT-1 showed a single class of binding sites on freshly isolated, nonstimulated human PMNs. The K(d) of VT-binding to PMNs was 10(-8) mol/L, 100-fold less than that of the VT-receptor globotriaosylceramide. On incubation of VT-preloaded PMNs with human glomerular microvascular endothelial cells (GMVECs), transfer of VT-1 to the endothelial cells occurred. Incubation of nonstimulated GMVECs with VT-preloaded PMNs, but not with PMNs or VT-1 alone, caused inhibition of protein synthesis and cell death. Our data are in concert with a role of PMNs in the transfer of VT from the intestine to the kidney endothelium. This transfer occurs by selective binding to a specific receptor on PMNs and subsequent passing of the ligand VT to the VT-receptor on GMVECs, which causes cell damage. This new mechanism further underpins the important role of PMNs in HUS.

Topics: Adult; Bacterial Toxins; Child; Endothelium, Vascular; Escherichia coli; Fluorescein-5-isothiocyanate; Hemolytic-Uremic Syndrome; Humans; In Vitro Techniques; Iodine Radioisotopes; Kidney Glomerulus; Kinetics; Lipoproteins; Lipoproteins, HDL; Lipoproteins, LDL; Lipoproteins, VLDL; Microcirculation; Neutrophils; Receptors, Cell Surface; Shiga Toxin 1; Trihexosylceramides

Verotoxin (VT) binding to the trisaccharide portion of globotriaosyl ceramide (Gb(3)) is believed to be a crucial step in the development of hemolytic uremic syndrome (HUS) commonly known as 'Hamburger disease'. This interaction is the initial step in the binding process and defines the specificity of verotoxin binding to cellular membranes. Although molecular modeling, co-crystallization and co-NMR studies with VT and the trisaccharide moiety of Gb(3) have indicated potential multiple sites for Gb(3) binding, little is known about their direct effects on kinetic and equilibrium binding. Here we describe how the binding of radiolabeled VT ([(125)I]VT1) to Gb(3) in a microtiter well format, is driven by two different association rate constants (k(+1a)=0.0075 and k(+1b)=0.275 min(-1) nM(-1)) with the high affinity site representing 15% of the total specific binding sites. Binding was reversible at room temperature, reached equilibrium after 2-3 h, and non-specific binding was less than 5%. Equilibrium binding studies defined by [(125)I]VT1 saturation binding to 15, 30, 60 and 120 ng Gb(3)/well, showed the presence of a single site with dissociation constants (K(d)s) ranging between 0.5 and 3 nM. However, the maximum density of specific [(125)I]VT1 binding sites (B(max)) did not directly correlate with the Gb(3) concentration per well: the most[(125)I]VT1 binding was observed for 60 ng Gb(3) (B(max)=1.28 nM; compared to 0. 23 nM for 30 ng Gb(3) and 0.65 nM for 120 ng Gb(3)). Furthermore, while Hill coefficients (n(H)) for 15, 30 and 120 ng Gb(3) were close to unity indicating single interactions, for the saturation isotherm for 60 ng Gb(3)/well n(H) was 1.4. Subsequent Scatchard analysis yielded a concave downward curve for [(125)I]VT1 binding to 60 ng Gb(3)/well, suggesting positive co-operativity. We present, for the first time, conclusive binding data confirming the presence of at least two discrete Gb(3) binding sites: these multivalent interactions between verotoxin VT-1 and Gb(3) were described by association reactions driven by two distinct rate constants, as well as by the positive co-operativity governing binding at a restricted receptor concentration. These results imply that the concentration of Gb(3) on the surface of target cells can have a complex, non-linear effect on verotoxin binding and thereby, on sensitivity to cytotoxicity.

Topics: Bacterial Toxins; Binding Sites; Enterotoxins; Escherichia coli; Hemolytic-Uremic Syndrome; Humans; Iodine Radioisotopes; Kinetics; Protein Binding; Receptors, Cell Surface; Shiga Toxin 1; Trihexosylceramides

We use immunohistochemistry to show the existence of verotoxin receptor in small sensory neurons in DRG of human, rabbit, rat and mouse. In capillary in nervous system, the verotoxin receptor exists in human and rabbit, but the receptor could not be demonstrated in rat and mouse, by this method. The receptors in sensory neuron of rat and in capillary in rabbit brain are determined as galactosylglobotriaosylceramide (GalGb3) and globotriaosylceramide (Gb3,), respectively. Although verotoxin was reported to bind to glycolipid receptors that possess the terminal disaccharide Galalpha1-4Galbeta (galactobiose), the binding to toxin to galabiosylceramide was half of that of GalGb3 which has galactobiose internally.

Topics: Animals; Bacterial Toxins; Brain; Capillaries; Fabry Disease; Fluorescent Antibody Technique; Ganglia, Spinal; Gangliosides; Glycolipids; Hemolytic-Uremic Syndrome; Humans; Lactosylceramides; Mice; Neurons, Afferent; Rabbits; Rats; Receptors, Cell Surface; Shiga Toxin 1; Trihexosylceramides

Acute renal failure is one of the hallmarks of the hemolytic uremic syndrome (HUS). Infection with a verocytotoxin (VT)- or Shiga-like toxin (SLT)-producing Escherichia coli has been strongly implicated in the etiology of the epidemic form of HUS. The functional receptor for these closely related toxins appears to be a glycosphingolipid, globotriaosylceramide (Gb3). Endothelial damage in the glomeruli and arterioles of the kidney induced by VT is believed to play a crucial role in the pathogenesis of HUS. However, little information is available regarding the effects of VT on mesangial cells, which also play an important role in glomerular function. In this study, the effects of VT on human mesangial cells in vitro were investigated. Mesangial cells were enriched by collecting hillock-shaped outgrowths derived from adult human glomeruli and subsequently purified by elimination of contaminating epithelial cells by immunoseparation with ulex europaeus lectin-I (UEA-I)-coated dynabeads. The obtained and subcultured mesangial cell populations were >98% pure. Their mesangial nature was established by the presence of a-smooth muscle cell actin in highly confluent cultures and the absence of cytokeratin or platelet/endothelial cell adhesion molecule-1. Mesangial cells bound VT to bands of Gb3 and a closely related glycolipid, which is similar to a glycolipid involved in the VT-dependent cytokine production in monocytes. VT did not induce the release of cytokines or chemokines in mesangial cells. In VT-susceptible cells, binding of VT to Gb3 causes cell death by the inhibition of protein synthesis. Although protein synthesis was inhibited in mesangial cells, all cells remained viable, both under basal and tumor necrosis factor-alpha-stimulated conditions. However, the marked reduction in protein synthesis may impair a proper response of the cells in conditions of increased demand of newly synthesized proteins. Furthermore, VT markedly inhibited DNA synthesis and proliferation of mesangial cells. The inhibition of mitogenesis was also found with the B-subunit of VT-1 alone, albeit to a lesser extent, without a significant effect on protein synthesis. Because the inhibition of protein synthesis involves the A-subunit, this suggests that two distinct mechanisms contribute to the effects of VT on protein synthesis and mitogenesis. Intracellular routing of VT (A- and B-subunits) may vary between cell types and result in differential effects on human mesangial cells wh

Topics: Acute Kidney Injury; Adult; Bacterial Toxins; Cell Division; Cell Survival; Cells, Cultured; DNA Replication; Escherichia coli Infections; Glomerular Mesangium; Glycolipids; Growth Inhibitors; Hemolytic-Uremic Syndrome; Humans; Muscle, Smooth, Vascular; Protein Biosynthesis; Protein Synthesis Inhibitors; Shiga Toxin 1; Trihexosylceramides; Tumor Necrosis Factor-alpha; Up-Regulation

The epidemic form of the hemolytic uremic syndrome (HUS) has been associated with a verocytotoxin producing Escherichia coli infection. Endothelial cell damage of glomeruli and arterioles of the kidney plays a central role in the pathogenesis of HUS. A number of observations in vivo and in vitro indicate that inflammatory mediators contribute to this process. In this study we investigated the binding of 125I-verocytotoxin-1 (VT-1) to freshly isolated human nonadherent monocytes as well as the nature of the ligand to which VT-1 binds on monocytes. On the average, freshly isolated monocytes have 0.07 x 10(5) specific binding sites for 125I-VT-1 per cell. Preincubation of nonadherent monocytes with bacterial lipopolysaccharide (LPS) caused a 23- to 30-fold increase of specific binding sites for VT-1 as shown by Scatchard plot analysis. Thin-layer chromatography of extracted neutral glycolipids of the cells and subsequent binding of 125I-VT-1 showed that human monocytes bind VT-1 to a globotriaosylceramide (Gb3) species that is different from that found on endothelial cells, probably a short-chain fatty acyl Gb3 or an alpha-OH-Gb3. In addition, we evaluated the functional consequences of VT-1 binding to human monocytes by investigating the effects of VT-1 on the total protein synthesis and, specifically, the production of the cytokines interleukin-1 beta (IL-1 beta), tumor necrosis factor-alpha (TNF-alpha), IL-6, and IL-8. We observed that VT-1 did not inhibit overall protein synthesis, nor under basal conditions, neither after stimulation with LPS, in contrast to previous observations with endothelial cells. Furthermore, we found that VT-1 induces the synthesis of the cytokines IL-1 beta, TNF-alpha, IL-6, and IL-8 in nonstimulated monocytes by a LPS-independent cell activation. The increase in the production of cytokines was parallelled by an increase in mRNA, as was demonstrated for IL-6 by reverse transcription-polymerase chain reaction. These data suggest that inflammatory mediators locally produced by VT-1-stimulated monocytes may contribute to the pathogenic mechanism of the HUS.

Topics: Bacterial Toxins; Binding Sites; Cell Culture Techniques; Cell Survival; Cells, Cultured; Escherichia coli; Gene Expression Regulation; Hemolytic-Uremic Syndrome; Humans; Interleukin-1; Interleukin-6; Interleukin-8; Interleukins; Ligands; Lipopolysaccharides; Male; Monocytes; Polytetrafluoroethylene; Protein Biosynthesis; Shiga Toxin 1; Trihexosylceramides; Tumor Necrosis Factor-alpha

Escherichia coli O157:H7-related vascular damage such as hemolytic uremic syndrome is believed to require the Shiga-like toxins. This study demonstrated that sodium butyrate sensitized human umbilical vein endothelial cells to Shiga toxin and increased the expression of Shiga toxin receptor, globotriaosylceramide (Gb3), on human umbilical vein endothelial cells.

Topics: Bacterial Toxins; Base Sequence; Butyrates; Butyric Acid; Cell Nucleus; Cells, Cultured; DNA Primers; Endothelium, Vascular; Hemolytic-Uremic Syndrome; Humans; Molecular Sequence Data; NF-kappa B; Receptors, Cell Surface; Shiga Toxins; Time Factors; Trihexosylceramides

Gastrointestinal infection with verotoxin-producing Escherichia coli (VTEC) has been strongly implicated in the etiology of the hemolytic uremic syndrome (HUS), the leading cause of pediatric acute renal failure. The binding of fluorescein-conjugated VT1 overlaid on to frozen human renal sections has been examined. Sections from biopsies of infants aged < 2 years were compared with those from adult autopsies. VT primarily stained distal convoluted tubules, particularly those adjacent to glomeruli, and collecting ducts. VT-binding was detected within the infant glomerulus but not the adult. Binding of the toxin was removed when the section was pretreated with alpha-galactosidase, confirming the receptor-binding specificity for globotriaosyl ceramide (gal alpha 1-4gal beta 1-4 glucosylceramide), the glycolipid receptor for VT. These studies may suggest that differential localization of this glycolipid in the pediatric renal glomerulus is a risk factor for the development of HUS following infection with VTEC.

Topics: Adult; Age Factors; alpha-Galactosidase; Bacterial Toxins; Carbohydrate Sequence; Child; Child, Preschool; Escherichia coli Infections; Gastrointestinal Diseases; Glycolipids; Hemolytic-Uremic Syndrome; Hepatorenal Syndrome; Histocytochemistry; Humans; In Vitro Techniques; Infant; Kidney; Molecular Sequence Data; Nephrosis, Lipoid; Receptors, Cell Surface; Shiga Toxin 1; Trihexosylceramides

This study addresses the basis for regional microvascular susceptibility to bacterial toxins implicated in hemolytic uremic syndrome. The results indicate a relationship between the degree of Shiga toxin sensitivity of human endothelial cells from different sources and the amount of globotriaosylceramide (Gb3) glycosphingolipid receptor for Shiga toxin expressed by these cells. Cell viability and protein synthesis of renal endothelial cells were reduced to 50% by 1 pM Shiga toxin, while umbilical vein cells were not affected by > 1 nM toxin. Similarly, basal levels of Gb3 were approximately 50 times higher in renal endothelial cells than in the umbilical endothelial cells. Pre-exposure of umbilical endothelial cells to tumor necrosis factor-alpha or bacterial lipopolysaccharide increased Gb3 content 4-6-fold coincident with increases in sensitivity to cytotoxic and protein synthesis inhibitory effects of Shiga toxin. Lipopolysaccharide induction of both Gb3 and sensitivity to Shiga toxin cytotoxic action in umbilical endothelial cells was dependent on the structure of lipopolysaccharide. Neither tumor necrosis factor-alpha nor lipopolysaccharide altered the Shiga toxin sensitivity or the Gb3 content of renal endothelial cells. These data indicate that differential endothelial expression of glycolipid receptors for Shiga toxins may be responsible for localized involvement of the kidney in hemolytic uremic syndrome.

Topics: Bacterial Toxins; Cells, Cultured; Endothelium, Vascular; Glycosphingolipids; Hemolytic-Uremic Syndrome; Humans; Kidney; Lipopolysaccharides; Shiga Toxins; Shigella; Trihexosylceramides; Tumor Necrosis Factor-alpha; Umbilical Cord

Development of hemolytic uremic syndrome (HUS) after infection by Shigella dysenteriae 1 or enterohemorrhagic Escherichia coli has been associated with the production of Shiga toxins (verotoxins). The putative target of Shiga toxins in HUS is the renal microvascular endothelium. This report shows that preincubation of human umbilical vein endothelial cells (HUVEC) with interleukin-1 beta (IL-1 beta) enhances the cytotoxic potency of Shiga toxin toward HUVEC. A preincubation of HUVEC with IL-1 beta is required for sensitization of HUVEC to Shiga toxin. Sensitization of HUVEC to Shiga toxin is IL-1 beta dose dependent. Development of the IL-1 beta response is time dependent, beginning within 2 h of IL-1 beta preincubation and increasing over the next 24 h. That these responses were due to IL-1 beta was demonstrated by heat inactivation of IL-1 beta, by neutralization of IL-1 beta by specific antibody, and by the ability of an IL-1 beta receptor antagonist to inhibit the effect of IL-1 beta. Shiga toxin-related inhibition of HUVEC protein synthesis preceded loss of cell viability. IL-1 beta incubation with HUVEC induced the receptor for Shiga toxin, globotriaosylceramide. Lipopolysaccharide included during IL-1 beta preincubation with HUVEC increased sensitivity to Shiga toxin in an additive manner. We conclude that IL-1 beta may induce Shiga toxin sensitivity in endothelial cells and contribute to the development of HUS.

Topics: Bacterial Toxins; Cell Survival; Cells, Cultured; Cytotoxins; Endothelium, Vascular; Hemolytic-Uremic Syndrome; Humans; Interleukin-1; Lipopolysaccharides; Protein Biosynthesis; Shiga Toxins; Shigella dysenteriae; Trihexosylceramides

The epidemic form of the hemolytic uremic syndrome (HUS), beginning with an acute gastroenteritis, has been associated with a verocytotoxin-producing Escherichia coli infection. The endothelial cell is believed to play an important role in the pathogenesis of HUS. Endothelial cell damage by verocytotoxin-1 (VT-1) in vitro is potentiated by the additional exposure of inflammatory mediators, such as tumor necrosis factor-alpha (TNF-alpha). Preincubation of human umbilical vein endothelial cells (HUVEC) with TNF-alpha resulted in a 10- to 100-fold increase of specific binding sites for 125I-VT-1. Furthermore, interleukin-1 (IL-1), lymphotoxin (TNF-beta), and lipopolysaccharide (LPS) also markedly increase VT-1 binding. Several hours' exposure to TNF-alpha was enough to enhance the number of VT-1 receptors on the endothelial cells for 2 days. The TNF-alpha-induced increase in VT-1 binding could be inhibited by simultaneous addition of the protein synthesis inhibitor cycloheximide. Glycolipid extracts of TNF-alpha-treated cells tested on thin-layer chromatography demonstrated an increase of globotriaosylceramide (GbOse3cer), a functional receptor for VT-1, which suggests that preincubation of human endothelial cells with TNF-alpha leads to an increase in GbOse3cer synthesis in these cells. We conclude from this study that TNF-alpha and IL-1 induce one (or more) enzyme(s) that is (are) rate-limiting in the synthesis of the glycolipid VT-1 receptor, GbOse3cer. These in vitro studies suggest that, in addition to VT-1, inflammatory mediators play an important role in the pathogenesis of HUS.

Topics: Bacterial Toxins; Carbohydrate Conformation; Carbohydrate Sequence; Cell Survival; Cells, Cultured; Cycloheximide; Endothelium, Vascular; Glycolipids; Hemolytic-Uremic Syndrome; Humans; Interleukin-1; Kinetics; Lipopolysaccharides; Molecular Sequence Data; Receptors, Cell Surface; Shiga Toxin 1; Time Factors; Trihexosylceramides; Tumor Necrosis Factor-alpha; Umbilical Veins

Fresh and transformed human B lineage cells were found to be sensitive to the cytotoxic action of Shiga-like toxin (SLT), a bacterial cytotoxin. The toxin was specifically bound by the glycolipids globotriosylceramide and galabiosylceramide expressed on the surface of sensitive cells. Mutant Daudi cells selected for resistance to SLT cytotoxicity (SLTR20) were deficient in SLT-binding glycolipids and failed to bind SLT to their surface, suggesting a role for these glycolipids in the mediation of SLT cytotoxicity. Of a number of normal and transformed lymphoid and myeloid cells screened for SLT sensitivity, only B lymphoid cells were susceptible to SLT action. Moreover, B lymphoid cells were the only cells expressing the SLT binding glycolipids. In vitro B cell activation studies with Epstein-Barr virus and pokeweed mitogen both indicated that the vast majority of SLT-sensitive B cells belong to the IgG and IgA committed subset, whereas most IgM and IgM/D producing cells were resistant to SLT toxicity. The selective elimination of IgG and IgA committed cells may explain the production of only IgM class anti-SLT antibodies in Shigella-infected humans leading to the failure of long-term immunity to dysenteric disease.

Topics: Antibodies, Bacterial; B-Lymphocytes; Bacterial Toxins; Burkitt Lymphoma; Cells, Cultured; Colitis; Cytotoxins; Escherichia coli; Escherichia coli Infections; Gangliosides; Glycolipids; Hemolytic-Uremic Syndrome; Humans; Lymphocyte Activation; Receptors, Cell Surface; Shiga Toxin 1; Trihexosylceramides; Tumor Cells, Cultured

Infection with verotoxin producing Escherichia coli has been strongly implicated in the etiology of the hemolytic uremic syndrome (HUS). We have previously shown that this toxin specifically binds to a glycolipid receptor-globotriosyl ceramide (Gb3). We have therefore quantitated the level of this glycolipid by HPLC in human renal cortex and medulla as a function of age. We have also measured the binding of verotoxin to Gb3 isolated from each renal tissue sample. Gb3 was a major component of the glycolipid fraction of all renal samples analyzed. The levels were found to be higher in the cortex than medulla, correlating with the clinical incidence of renal lesions in HUS, but reduced in the kidneys of infants as compared to adults. Verotoxin binding was directly proportional to the renal Gb3 content. Thus, human renal tissue is a rich source of the verotoxin receptor glycolipid. However, changes in receptor concentration cannot explain the age-related incidence of HUS.

Topics: Aging; Bacterial Toxins; Chromatography, High Pressure Liquid; Cytotoxins; Escherichia coli Infections; Globosides; Glycolipids; Glycosphingolipids; Hemolytic-Uremic Syndrome; Humans; Kidney Cortex; Kidney Medulla; Receptors, Cell Surface; Receptors, Immunologic; Shiga Toxin 1; Trihexosylceramides