Isolation of Outer Membrane Vesicles from Helicobacter pylori.

Outer membrane vesicles (OMV) shed by pathogenic bacteria have multifunctional roles in disease initiation and progression. Further, their efficacy as novel vaccines has underscored their importance as potential therapeutics. Consequently, to advance allied research related to their immunogenicity and pathogenicity it is important to separate these vesicular structures from parental cells and demonstrate them to be free from cellular debris and other non-vesicle-related constituents such as protein aggregates.

Surface layer proteins from virulent Clostridium difficile ribotypes exhibit signatures of positive selection with consequences for innate immune response.

Background: Clostridium difficile is a nosocomial pathogen prevalent in hospitals worldwide and increasingly common in the community. Sequence differences have been shown to be present in the Surface Layer Proteins (SLPs) from different C. difficile ribotypes (RT) however whether these differences influence severity of infection is still not clear.

Etiological Role and Repeated Infections of Sapovirus among Children Aged Less than 2 Years in a Cohort Study in a Peri-urban Community of Peru.

Human sapovirus has been shown to be one of the most important etiologies in pediatric patients with acute diarrhea. However, very limited data are available about the causative roles and epidemiology of sapovirus in community settings. A nested matched case-control study within a birth cohort study of acute diarrhea in a peri-urban community in Peru from 2007 to 2010 was conducted to investigate the attributable fraction (AF) and genetic diversity of sapovirus.

Bismuth coordination networks containing deferiprone: synthesis, characterisation, stability and antibacterial activity.

A series of bismuth-dicarboxylate-deferiprone coordination networks have been prepared and structurally characterised. The new compounds have been demonstrated to release the iron overload drug deferiprone on treatment with PBS and have also been shown to have antibacterial activity against H. pylori.

First detected Helicobacter pylori infection in infancy modifies the association between diarrheal disease and childhood growth in Peru.

Background: In endemic settings, Helicobacter pylori infection can occur shortly after birth and may be associated with a reduction in childhood growth.

Materials And Methods: This study investigated what factors promote earlier age of first H. pylori infection and evaluated the role of H.

Surface layer proteins isolated from Clostridium difficile induce clearance responses in macrophages.

Clostridium difficile is the leading cause of hospital-acquired diarrhoea worldwide, and if the bacterium is not cleared effectively it can pose a risk of recurrent infections and complications such as colitis, sepsis and death. In this study we demonstrate that surface layer proteins from the one of the most frequently acquired strains of C. difficile, activate mechanisms in murine macrophage in vitro that are associated with clearance of bacterial infection.

Iron status and Helicobacter pylori infection in symptomatic children: an international multi-centered study.

Objective: Iron deficiency (ID) and iron deficiency anaemia (IDA) are global major public health problems, particularly in developing countries. Whilst an association between H. pylori infection and ID/IDA has been proposed in the literature, currently there is no consensus.

A short chain NAD(H)-dependent alcohol dehydrogenase (HpSCADH) from Helicobacter pylori: a role in growth under neutral and acidic conditions.

Toxic aldehydes produced by alcohol dehydrogenases have been implicated in the pathogenesis of Helicobacter pylori-related damage to the gastric mucosa. Despite this, the enzymes that might be responsible for producing such aldehydes have not been fully described. It was, therefore, of considerable interest to characterize the alcohol oxidizing enzymes in this pathogen.

A nitrophenyl-based prodrug type for colorectal targeting of prednisolone, budesonide and celecoxib.

Celecoxib is a COX-2 inhibitor drug that can be used to reduce the risk of colorectal adenocarcinoma. Glucocorticoids are used in the treatment of inflammatory bowel disease. A limitation to the use of both drug types is that they undergo absorption from the intestinal tract with serious side effects.

Helicobacter pylori-associated hypochlorhydria in children, and development of iron deficiency.

Aims: Acute Helicobacter pylori infection is associated with transient hypochlorhydria. In H pylori-associated atrophy, hypochlorhydria has a role in iron deficiency (ID) through changes in the physiology of iron-complex absorption. The aims were to evaluate the association between H pylori-associated hypochlorhydria and ID in children.

Structure requirements for anaerobe processing of azo compounds: implications for prodrug design.

This Letter generalizes the metabolism of the azo class of compounds by Clostridium perfringens, an anaerobe found in the human colon. A recently reported 5-aminosalicylic acid-based prednisolone prodrug was shown to release the drug when incubated with the bacteria, while the para-aminobenzoic acid (PABA) based analogue did not. Instead, it showed a new HPLC peak with a relatively close retention time to the parent which was identified by LCMS as the partially reduced hydrazine product.

Azo-reductase activated budesodine prodrugs for colon targeting.

Budesodine is a synthetic glurocorticoid that undergoes substantial first pass metabolism, limiting systemic exposure. Its use in treatment of inflammatory bowel disease would benefit from a targeting strategy that could lead to a local topical effect, improving safety and increasing anti-inflammatory efficacy. A two-step prodrug strategy involving azoreduction/cyclization that we developed previously for prednisolone is here applied with some variations to budesonide.

Alkyl hydroperoxide reductase: a candidate Helicobacter pylori vaccine.

Helicobacter pylori (H. pylori) is the most important etiological agent of chronic active gastritis, peptic ulcer disease and gastric cancer. The aim of this study was to evaluate the efficacy of alkyl hydroperoxide reductase (AhpC) and mannosylated AhpC (mAhpC) as candidate vaccines in the C57BL/6J mouse model of H.

A double prodrug system for colon targeting of benzenesulfonamide COX-2 inhibitors.

The design, synthesis and delivery potential of a new type of benzenesulfonamide cyclo-oxygenase-2 (COX-2) inhibitor prodrug is investigated using celecoxib. The approach involves a double prodrug that is activated first by azoreductases and then by cyclization triggering drug release. We studied the intramolecular aminolysis of the acylsulfonamide.

Investigation into drug release from colon-specific azoreductase-activated steroid prodrugs using in-vitro models.

Objectives: The aim of this study was to investigate drug release from a double steroid prodrug, OPN501, which incorporates a phenylpropionate linker, and its phenylacetate analogue. The prodrugs, which were designed to deliver prednisolone to the colon for the treatment of inflammatory bowel disease, are based on a novel design that requires sequential azoreductase activity and cyclization of an amino ester to trigger drug release. We sought to explain the divergent effects of the two compounds in anti-inflammatory models and to justify the selection of OPN-501 for clinical development.

Tribbles 3: a novel regulator of TLR2-mediated signaling in response to Helicobacter pylori lipopolysaccharide.

Helicobacter pylori causes chronic gastritis, peptic ulcers, and gastric carcinoma. Gastric epithelial cells provide the first point of contact between H. pylori and the host.

Proteomics of bacterial pathogenicity: therapeutic implications.

Identification of the molecular mechanisms of host-pathogen interaction is becoming a key focus of proteomics. Analysis of these interactions holds promise for significant developments in the identification of new therapeutic strategies to combat infectious diseases, a process that will also benefit parallel improvements in molecular diagnostics, biomarker identification and drug discovery. This review highlights recent advances in functional proteomics initiatives in infectious disease with emphasis on studies undertaken within physiologically relevant parameters that enable identification of the infectious proteome rather than that of the vegetative state.

Proteomic and functional characterization of the outer membrane vesicles from the gastric pathogen Helicobacter pylori.

The gastric pathogen Helicobacter pylori causes a spectrum of gastro-duodenal diseases, which may be mediated in part by the outer membrane vesicles (OMVs) constitutively shed by the pathogen. We aimed to determine the proteome of H. pylori OMV to help evaluate the mechanisms whereby these structures confer their known immuno-modulatory and cytotoxic activities to host cells, as such disease-associated activities are also conferred by the bacterium from which the vesicles are derived.

A new mechanism of gastric epithelial injury induced by acid exposure: the role of Egr-1 and ERK signaling pathways.

The molecular mechanisms by which gastric acid causes epithelial injury in the stomach and initiates an inflammatory reaction are poorly understood. We aimed in the present study to investigate the role of the early growth response gene Egr-1 and ERK in gastric epithelial cells following acid exposure, and the signaling pathways involved. Western blotting was used to assess Egr-1 protein levels in AGS cells.

Design, synthesis, and pharmacological effects of a cyclization-activated steroid prodrug for colon targeting in inflammatory bowel disease.

Glucocorticoids are used in the treatment of inflammatory bowel disease. A limitation to their use is that they undergo absorption from the GIT before reaching the colon causing severe systemic side effects. We report here on a novel prodrug approach to targeting corticosteroids to the colon.

Aldo-keto reductase from Helicobacter pylori--role in adaptation to growth at acid pH.

Pyridine-linked oxidoreductase enzymes of Helicobacter pylori have been implicated in the pathogenesis of gastric disease. Previous studies in this laboratory examined a cinnamyl alcohol dehydrogenase that was capable of detoxifying a range of aromatic aldehydes. In the present work, we have extended these studies to identify and characterize an aldoketo reductase (AKR) enzyme present in H.

Childhood Helicobacter pylori infection and growth impairment in developing countries: a vicious cycle?

We hypothesize that infection with the gastric pathogen Helicobacter pylori in children in developing countries is the initiator of a vicious cycle of events that result ultimately in malnutrition and growth impairment. Acute infection with H. pylori is accompanied by hypochlorhydria, which facilitates the acquisition of other enteropathogens because of removal of the gastric acid barrier, which then results in diarrheal disease and iron-deficiency anemia.

Helicobacter pylori extract induces nuclear factor-kappa B, activator protein-1, and cyclooxygenase-2 in esophageal epithelial cells.

Helicobacter pylori infection is recognized as the major cause of gastritis and gastric cancer; however, its role in the development of gastroesophageal reflux disease and Barrett's adenocarcinoma is unclear. The expression of NF-kappaB, AP-1, and COX-2 may be important in inflammation and tumorigenesis in the esophagus. The aim of this study was to examine the effect of live H pylori or H pylori extract (HPE) on these factors in the esophageal epithelial cell lines SKGT-4 and OE33.

Helicobacter pylori thioredoxin is an arginase chaperone and guardian against oxidative and nitrosative stresses.

The gastric human pathogen Helicobacter pylori faces formidable challenges in the stomach including reactive oxygen and nitrogen intermediates. Here we demonstrate that arginase activity, which inhibits host nitric oxide production, is post-translationally stimulated by H. pylori thioredoxin (Trx) 1 but not the homologous Trx2.