Enhanced enzymatic production of cholesteryl 6'-acylglucoside impairs lysosomal degradation for the intracellular survival of Helicobacter pylori.

BACKGROUND: During autophagy defense against invading microbes, certain lipid types are indispensable for generating specialized membrane-bound organelles. The lipid composition of autophagosomes remains obscure, as does the issue of how specific lipids and lipid-associated enzymes participate in autophagosome formation and maturation. Helicobacter pylori is auxotrophic for cholesterol and converts cholesterol to cholesteryl glucoside derivatives, including cholesteryl 6'-O-acyl-α-D-glucoside (CAG). We investigated how CAG and its biosynthetic acyltransferase assist H. pylori to escape host-cell autophagy. METHODS: We applied a metabolite-tagging method to obtain fluorophore-containing cholesteryl glucosides that were utilized to understand their intracellular locations. H. pylori 26695 and a cholesteryl glucosyltransferase (CGT)-deletion mutant (ΔCGT) were used as the standard strain and the negative control that contains no cholesterol-derived metabolites, respectively. Bacterial internalization and several autophagy-related assays were conducted to unravel the possible mechanism that H. pylori develops to hijack the host-cell autophagy response. Subcellular fractions of H. pylori-infected AGS cells were obtained and measured for the acyltransferase activity. RESULTS: The imaging studies of fluorophore-labeled cholesteryl glucosides pinpointed their intracellular localization in AGS cells. The result indicated that CAG enhances the internalization of H. pylori in AGS cells. Particularly, CAG, instead of CG and CPG, is able to augment the autophagy response induced by H. pylori. How CAG participates in the autophagy process is multifaceted. CAG was found to intervene in the degradation of autophagosomes and reduce lysosomal biogenesis, supporting the idea that intracellular H. pylori is harbored by autophago-lysosomes in favor of the bacterial survival. Furthermore, we performed the enzyme activity assay of subcellular fractions of H. pylori-infected AGS cells. The analysis showed that the acyltransferase is mainly distributed in autophago-lysosomal compartments. CONCLUSIONS: Our results support the idea that the acyltransferase is mainly distributed in the subcellular compartment consisting of autophagosomes, late endosomes, and lysosomes, in which the acidic environment is beneficial for the maximal acyltransferase activity. The resulting elevated level of CAG can facilitate bacterial internalization, interfere with the autophagy flux, and causes reduced lysosomal biogenesis.

Functionally significant polymorphisms of the MMP-9 gene are associated with peptic ulcer disease in the Caucasian population of Central Russia.

This study analyzed the association of functionally significant SNPs of matrix metalloproteinase (MMP) genes in the development of peptic ulcer disease (PUD) in Caucasians from Central Russia. Ten SNPs of the MMP-1, MMP-2, MMP-3, MMP-8, and MMP-9 genes were analyzed for association with PUD in a cohort of 798 patients with PUD (including 404 H. pylori-positive and 394 H. pylori-negative) and 347 H. pylori-negative controls using logistic regression and assuming the additive, recessive, and dominant genetic models. The variants of MMP-1, MMP-2, MMP-3, and MMP-8 did not manifest any significant associations with the diseases. Five SNPs of the MMP-9 gene demonstrated such association. Allele G of the rs17576 MMP-9 locus conferred a higher risk for PUD (ORadj = 1.31, pperm = 0.016), haplotype AACG of loci rs17576-rs3787268-rs2250889-rs17577 of the MMP-9 gene decreased risk for PUD (ORadj = 0.17, pperm = 0.003). Also, allele C of rs3918249, allele G of rs17576 and haplotype CG of rs3918249-rs17576 of the MMP-9 gene increased risk for H. pylori-positive PUD (ORadj = 1.82, pperm = 0.002; ORadj = 1.53-1.95 pperm = 0.001-0.013 and ORadj = 1.49 pperm = 0.009 respectively). The above loci and 50 linked to them possess significant regulatory effects and may affect the alternative splicing of four genes and the expression of 17 genes in various organs and tissues related to the PUD pathogenesis.

In vivo activation of pH-responsive oxidase-like graphitic nanozymes for selective killing of Helicobacter pylori.

Helicobacter pylori infection is a major etiological factor in gastric diseases. However, clinical antibiotic therapy for H. pylori is limited by continuously decreased therapeutic efficacy and side effects to symbiotic bacteria. Herein, we develop an in vivo activatable pH-responsive graphitic nanozyme, PtCo@Graphene (PtCo@G), for selective treatment of H. pylori. Such nanozymes can resist gastric acid corrosion, exhibit oxidase-like activity to stably generate reactive oxygen species only in acidic gastric milieu and demonstrate superior selective bactericidal property. C18-PEGn-Benzeneboronic acid molecules are modified on PtCo@G, improving its targeting capability. Under acidic gastric pH, graphitic nanozymes show notable bactericidal activity toward H. pylori, while no bacterial killing is observed under intestinal conditions. In mouse model, high antibacterial capability toward H. pylori and negligible side effects toward normal tissues and symbiotic bacteria are achieved. Graphitic nanozyme displays the desired enzyme-like activities at corresponding physiological sites and may address critical issues in clinical treatment of H. pylori infections.

ß-Carotene Inhibits Expression of Matrix Metalloproteinase-10 and Invasion in Helicobacter pylori-Infected Gastric Epithelial Cells.

Matrix metalloproteinases (MMPs), key molecules of cancer invasion and metastasis, degrade the extracellular matrix and cell-cell adhesion molecules. MMP-10 plays a crucial role in Helicobacter pylori-induced cell-invasion. The mitogen-activated protein kinase (MAPK) signaling pathway, which activates activator protein-1 (AP-1), is known to mediate MMP expression. Infection with H. pylori, a Gram-negative bacterium, is associated with gastric cancer development. A toxic factor induced by H. pylori infection is reactive oxygen species (ROS), which activate MAPK signaling in gastric epithelial cells. Peroxisome proliferator-activated receptor γ (PPAR-γ) mediates the expression of antioxidant enzymes including catalase. ß-Carotene, a red-orange pigment, exerts antioxidant and anti-inflammatory properties. We aimed to investigate whether ß-carotene inhibits H. pylori-induced MMP expression and cell invasion in gastric epithelial AGS (gastric adenocarcinoma) cells. We found that H. pylori induced MMP-10 expression and increased cell invasion via the activation of MAPKs and AP-1 in gastric epithelial cells. Specific inhibitors of MAPKs suppressed H. pylori-induced MMP-10 expression, suggesting that H. pylori induces MMP-10 expression through MAPKs. ß-Carotene inhibited the H. pylori-induced activation of MAPKs and AP-1, expression of MMP-10, and cell invasion. Additionally, it promoted the expression of PPAR-γ and catalase, which reduced ROS levels in H. pylori-infected cells. In conclusion, ß-carotene exerts an inhibitory effect on MAPK-mediated MMP-10 expression and cell invasion by increasing PPAR-γ-mediated catalase expression and reducing ROS levels in H. pylori-infected gastric epithelial cells.

Spermine oxidase mediates Helicobacter pylori-induced gastric inflammation, DNA damage, and carcinogenic signaling.

Helicobacter pylori infection is the main risk factor for the development of gastric cancer, the third leading cause of cancer death worldwide. H. pylori colonizes the human gastric mucosa and persists for decades. The inflammatory response is ineffective in clearing the infection, leading to disease progression that may result in gastric adenocarcinoma. We have shown that polyamines are regulators of the host response to H. pylori, and that spermine oxidase (SMOX), which metabolizes the polyamine spermine into spermidine plus H2O2, is associated with increased human gastric cancer risk. We now used a molecular approach to directly address the role of SMOX, and demonstrate that Smox-deficient mice exhibit significant reductions of gastric spermidine levels and H. pylori-induced inflammation. Proteomic analysis revealed that cancer was the most significantly altered functional pathway in Smox-/- gastric organoids. Moreover, there was also less DNA damage and ß-catenin activation in H. pylori-infected Smox-/- mice or gastric organoids, compared to infected wild-type animals or gastroids. The link between SMOX and ß-catenin activation was confirmed in human gastric organoids that were treated with a novel SMOX inhibitor. These findings indicate that SMOX promotes H. pylori-induced carcinogenesis by causing inflammation, DNA damage, and activation of ß-catenin signaling.

Association of cagA+ Helicobacter pylori strains with high urease activity and dyspepsia in Mexican adults. / Asociación de cepas de Helicobater pylori cagA+ con alta actividad de ureasa y dispepsia en adultos mexicanos.

INTRODUCTION AND AIMS: Helicobacter pylori (H. pylori) is associated with a higher risk of peptic ulcer and gastric cancer. The sole presence of the bacterium is not a determinant of clinical outcome, but rather the interaction of strain type and host factors determines the risk of disease. Our aim was to study the association between bacterial load, strain type, and gastric symptoms in H. pylori-positive subjects. MATERIALS AND METHODS: In a community survey, a diagnostic 13C-urea breath test for H. pylori was performed on 302 volunteers that were not taking antibiotics, antacids, or proton pump inhibitors one month prior to the test. The breath test produced 25 H. pylori-positive subjects, between 25-74 years of age, who then took a gastric symptoms survey and were tested for the presence of the cagA genotype in gastric juice, using the Entero-test®. Bacterial load was determined as a measure of urease activity, utilizing the delta over baseline value, obtained in the 13C-urea breath test. RESULTS: A total of 48% of the H. pylori-positive subjects were cagA+. A positive association was found between cagA status and high gastric urease activity (P<.0001) and the latter was significantly associated with the presence of symptoms (P<.0001). CONCLUSION: Gastric urease activity was strongly associated with dyspeptic symptoms and cagA+ H. pylori. Elevated 13C-delta over baseline values could be used as indicators of a higher risk for gastric disease.

Helicobacter pylori infection impairs chaperone-assisted maturation of Na-K-ATPase in gastric epithelium.

Helicobacter pylori infection always induces gastritis, which may progress to ulcer disease or cancer. The mechanisms underlying mucosal injury by the bacteria are incompletely understood. Here, we identify a novel pathway for H. pylori-induced gastric injury, the impairment of maturation of the essential transport enzyme and cell adhesion molecule, Na-K-ATPase. Na-K-ATPase comprises α- and ß-subunits that assemble in the endoplasmic reticulum (ER) before trafficking to the plasma membrane. Attachment of H. pylori to gastric epithelial cells increased Na-K-ATPase ubiquitylation, decreased its surface and total levels, and impaired ion balance. H. pylori did not alter degradation of plasmalemma-resident Na-K-ATPase subunits or their mRNA levels. Infection decreased association of α- and ß-subunits with ER chaperone BiP and impaired assembly of α/ß-heterodimers, as was revealed by quantitative mass spectrometry and immunoblotting of immunoprecipitated complexes. The total level of BiP was not altered, and the decrease in interaction with BiP was not observed for other BiP client proteins. The H. pylori-induced decrease in Na-K-ATPase was prevented by BiP overexpression, stopping protein synthesis, or inhibiting proteasomal, but not lysosomal, protein degradation. The results indicate that H. pylori impairs chaperone-assisted maturation of newly made Na-K-ATPase subunits in the ER independently of a generalized ER stress and induces their ubiquitylation and proteasomal degradation. The decrease in Na-K-ATPase levels is also seen in vivo in the stomachs of gerbils and chronically infected children. Further understanding of H. pylori-induced Na-K-ATPase degradation will provide insights for protection against advanced disease.NEW & NOTEWORTHY This work provides evidence that Helicobacter pylori decreases levels of Na-K-ATPase, a vital transport enzyme, in gastric epithelia, both in acutely infected cultured cells and in chronically infected patients and animals. The bacteria interfere with BiP-assisted folding of newly-made Na-K-ATPase subunits in the endoplasmic reticulum, accelerating their ubiquitylation and proteasomal degradation and decreasing efficiency of the assembly of native enzyme. Decreased Na-K-ATPase expression contributes to H. pylori-induced gastric injury.

Helicobacter pylori inhibits GKN1 expression via the CagA/p-ERK/AUF1 pathway.

BACKGROUND: Recent studies have shown that gastrokine 1 (GKN1), an important tumor suppressor gene, is downregulated in Helicobacter pylori (H. pylori) infected gastric mucosa and gastric cancer. However, the underlying mechanism is poorly understood. Herein, we investigated the potential mechanism of H. pylori-induced GKN1 downregulation. MATERIALS AND METHODS: GKN1 and AU-rich element RNA-binding factor 1 (AUF1) expressions were assessed by quantitative real-time PCR, Western blot, or immunohistochemistry in H. pylori-infected tissues and H. pylori co-cultured cell lines. The regulation of AUF1 on GKN1 was determined by RNA pulldown assay, RNA immunoprecipitation, mRNA turnover, and luciferase activity assays. The involvement of phosphorylated extra-cellular signal-regulated kinase (p-ERK) or CagA in H. pylori-induced AUF1 expression was verified using p-ERK inhibitor or CagA knockout H. pylori. In addition, the cell proliferation and migration capacities of AUF1-knockdown cells were investigated. RESULTS: GKN1 expression progressively decreased from H. pylori-infected gastritis to gastric cancer tissues. H. pylori co-culture also induced significant GKN1 reduction in GES-1 and BGC-823 cells. Besides, the mRNA level of GKN1 and AUF1 in human gastric mucosa showed negative correlation significantly. AUF1 knockdown resulted in upregulation of GKN1 expression and promoted GKN1 mRNA decay by binding the 3' untranslated region of GKN1 mRNA H. pylori-induced AUF1 expression was associated with p-ERK activation and CagA. Furthermore, knockdown of AUF1 significantly inhibited cell viability, migration ability, and arrested fewer cells in S-phase. CONCLUSION: Our data demonstrated that H. pylori infection downregulated GKN1 expression via the CagA/p-ERK/AUF1 pathway. AUF1 promoted gastric cancer at least partly through downregulating GKN1, which presented a novel potential target for the treatment of gastric cancer.

Tetramerization at Low pH Licenses DNA Methylation Activity of M.HpyAXI in the Presence of Acid Stress.

Methylation of genomic DNA can influence the transcription profile of an organism and may generate phenotypic diversity for rapid adaptation in a dynamic environment. M.HpyAXI is a Type III DNA methyltransferase present in Helicobacter pylori and is upregulated at low pH. This enzyme may alter the expression of critical genes to ensure the survival of this pathogen at low pH inside the human stomach. M.HpyAXI methylates the adenine in the target sequence (5'-GCAG-3') and shows maximal activity at pH 5.5. Type III DNA methyltransferases are found to form an inverted dimer in the functional form. We observe that M.HpyAXI forms a nonfunctional dimer at pH 8.0 that is incapable of DNA binding and methylation activity. However, at pH 5.5, two such dimers associate to form a tetramer that now includes two functional dimers that can bind and methylate the target DNA sequence. Overall, we observe that the pH-dependent tetramerization of M.HpyAXI ensures that the enzyme is licensed to act only in the presence of acid stress.

Tyrosine Kinases in Helicobacter pylori Infections and Gastric Cancer.

Helicobacter pylori (H. pylori) has been identified as a leading cause of gastric cancer, which is one of the most frequent and malignant types of tumor. It is characterized by its rapid progression, distant metastases, and resistance to conventional chemotherapy. A number of receptor tyrosine kinases and non-receptor tyrosine kinases have been implicated in H. pylori-mediated pathogenesis and tumorigenesis. In this review, recent findings of deregulated EGFR, c-Met, JAK, FAK, Src, and c-Abl and their functions in H. pylori pathogenesis are summarized.

GENDER, AGE, ENDOSCOPIC FINDINGS, UREASE AND HELICOBACTER PYLORI : ALL UNCORRELATED WITHIN A SAMPLE OF A HIGH GASTRIC CANCER PREVALENCE POPULATION IN AMAZON.

BACKGROUND: It is widely assumed that gender, age, gastritis and Helicobacter pylori , all have some degree of correlation and, therefore, can synergistically lead to the development of gastric cancer. OBJECTIVE: In this cross-sectional study, we expected to observe the above mentioned correlation in the analysis of medical records of 67 patients of both sexes (female, n=44), mean age ± standard deviation: 41±12 years old, all from Belém (capital of Pará State, Brazilian Amazon), a city historically known as one with the highest gastric cancer prevalence in this country. METHODS: All patients were submitted to upper gastrointestinal endoscopy for gastric biopsy histopathological analysis and rapid urease test. All diagnoses of gastritis were recorded considering its topography, category and the degree of inflammatory activity, being associated or not associated with H. pylori infection. RESULTS: The results show that no statistically relevant associations were found among the prevalences of the observed variables. CONCLUSION: The authors hypothesize that observed risk factors associated to gastric cancer might be lesser synergistic than is usually expected.

Gênero, idade, achados endoscópicos, urease e Helicobacter pylori: ausência de correlação dentro de uma amostra de população com alta prevalência de câncer gástrico na Amazônia / Gender, age, endoscopic findings, urease and helicobacter pylori: all uncorrelated within a sample of a high gastric cancer prevalence population in amazon

ABSTRACT BACKGROUND: It is widely assumed that gender, age, gastritis and Helicobacter pylori , all have some degree of correlation and, therefore, can synergistically lead to the development of gastric cancer. OBJECTIVE: In this cross-sectional study, we expected to observe the above mentioned correlation in the analysis of medical records of 67 patients of both sexes (female, n=44), mean age ± standard deviation: 41±12 years old, all from Belém (capital of Pará State, Brazilian Amazon), a city historically known as one with the highest gastric cancer prevalence in this country. METHODS: All patients were submitted to upper gastrointestinal endoscopy for gastric biopsy histopathological analysis and rapid urease test. All diagnoses of gastritis were recorded considering its topography, category and the degree of inflammatory activity, being associated or not associated with H. pylori infection. RESULTS: The results show that no statistically relevant associations were found among the prevalences of the observed variables. CONCLUSION: The authors hypothesize that observed risk factors associated to gastric cancer might be lesser synergistic than is usually expected.

RESUMO CONTEXTO: É amplamente assumido que gênero, idade, gastrite e Helicobacter pylori , todos têm algum grau de correlação e, portanto, podem sinergicamente levar ao desenvolvimento de câncer gástrico. OBJETIVO: Neste estudo transversal, esperamos observar a correlação acima mencionada na análise de prontuários de 67 pacientes de ambos os sexos (sexo feminino, n=44), média de idade ± desvio padrão: 41±12 anos, todos de Belém (capital do Estado do Pará, Amazônia Brasileira), uma cidade historicamente conhecida como sendo uma das que apresenta maior prevalência de câncer gástrico no país. MÉTODOS: Todos os pacientes foram submetidos à endoscopia digestiva alta para análise histopatológica da biópsia gástrica e teste rápido da urease. Todos os diagnósticos de gastrite foram registrados considerando sua topografia, categoria e grau de atividade inflamatória, sendo associada ou não associada à infecção por H. pylori . RESULTADOS: Os resultados mostram que não foram encontradas associações estatisticamente relevantes entre as prevalências das variáveis observadas. CONCLUSÃO: Os autores levantam a hipótese de que os fatores de risco associados ao câncer gástrico podem ser menos sinérgicos do que o esperado.

Comparison of the Clinicopathological Characteristics and Genetic Alterations Between Patients with Gastric Cancer with or Without Helicobacter pylori Infection.

BACKGROUND: Helicobacter pylori (HP) can induce epithelial cells and intestinal metaplasia with genetic damage that makes them highly susceptible to the development of gastric cancer (GC). MATERIALS AND METHODS: Between 2005 and 2010, 356 patients with gastric cancer who received curative surgery were enrolled. Analysis of HP, Epstein-Barr virus (EBV) infection, PIK3CA amplification, and mutation analysis of 68 mutations in eight genes using a mass spectrometric single-nucleotide polymorphism genotyping technology was conducted. The clinicopathological characteristics of patients with or without HP infection were compared. RESULTS: Among the 356 patients, 185 (52.0%) had HP infection. For intestinal-type GC, patients with HP infection were more likely to be younger and had fewer PI3K/AKT pathway genetic mutations than those without HP infection. For diffuse-type GC, patients with HP infection were characterized by less male predominance, less lymphoid stroma, fewer microsatellite instability-high tumors, and fewer PI3K/AKT pathway genetic mutations than those without HP infection. Patients with HP infection had less tumor recurrence and a better 5-year overall survival (87.7% vs. 73.9%, p = .012) and disease-free survival (64.1% vs. 51.3%, p = .013) than those without HP infection, especially for intestinal-type GC. For EBV-negative GC, patients with HP infection had fewer PI3K/AKT pathway mutations and a better 5-year overall survival and disease-free survival than those without HP infection. Multivariate analysis demonstrated that HP infection was an independent prognostic factor regarding overall survival and disease-free survival. CONCLUSION: Patients with GC with HP infection were associated with fewer PI3K/AKT pathway genetic mutations and better survival than those without HP infection, especially for EBV-negative and intestinal-type GC. IMPLICATIONS FOR PRACTICE: Patients with gastric cancer with Helicobacter pylori (HP) infection had fewer PI3K/AKT pathway genetic mutations, less tumor recurrence, and better survival than those without HP infection, especially for Epstein-Barr virus (EBV)-negative and intestinal-type gastric cancer. HP infection is an independent prognostic factor regarding overall survival and disease-free survival. Future in vivo and in vitro studies of the correlation among HP infection, PI3K/AKT pathway, and EBV infection in gastric cancer are required.

Phytochemicals in Helicobacter pylori Infections: What Are We Doing Now?

In this critical review, plant sources used as effective antibacterial agents against Helicobacter pylori infections are carefully described. The main intrinsic bioactive molecules, responsible for the observed effects are also underlined and their corresponding modes of action specifically highlighted. In addition to traditional uses as herbal remedies, in vitro and in vivo studies focusing on plant extracts and isolated bioactive compounds with anti-H. pylori activity are also critically discussed. Lastly, special attention was also given to plant extracts with urease inhibitory effects, with emphasis on involved modes of action.

Acetylation-mediated Siah2 stabilization enhances PHD3 degradation in Helicobacter pylori-infected gastric epithelial cancer cells.

Gastric epithelial cells infected with Helicobacter pylori acquire highly invasive and metastatic characteristics. The seven in absentia homolog (Siah)2, an E3 ubiquitin ligase, is one of the major proteins that induces invasiveness of infected gastric epithelial cells. We find that p300-driven acetylation of Siah2 at lysine 139 residue stabilizes the molecule in infected cells, thereby substantially increasing its efficiency to degrade prolyl hydroxylase (PHD)3 in the gastric epithelium. This enhances the accumulation of an oncogenic transcription factor hypoxia-inducible factor 1α (Hif1α) in H. pylori-infected gastric cancer cells in normoxic condition and promotes invasiveness of infected cells. Increased acetylation of Siah2, Hif1α accumulation, and the absence of PHD3 in the infected human gastric metastatic cancer biopsy samples and in invasive murine gastric cancer tissues further confirm that the acetylated Siah2 (ac-Siah2)-Hif1α axis is crucial in promoting gastric cancer invasiveness. This study establishes the importance of a previously unrecognized function of ac-Siah2 in regulating invasiveness of H. pylori-infected gastric epithelial cells.-Kokate, S. B., Dixit, P., Das, L., Rath, S., Roy, A. D., Poirah, I., Chakraborty, D., Rout, N., Singh, S. P., Bhattacharyya, A. Acetylation-mediated Siah2 stabilization enhances PHD3 degradation in Helicobacter pylori-infected gastric epithelial cancer cells.

The Sole DEAD-Box RNA Helicase of the Gastric Pathogen Helicobacter pylori Is Essential for Colonization.

Present in every kingdom of life, generally in multiple copies, DEAD-box RNA helicases are specialized enzymes that unwind RNA secondary structures. They play major roles in mRNA decay, ribosome biogenesis, and adaptation to cold temperatures. Most bacteria have multiple DEAD-box helicases that present both specialized and partially redundant functions. By using phylogenomics, we revealed that the Helicobacter genus, including the major gastric pathogen H. pylori, is among the exceptions, as it encodes a sole DEAD-box RNA helicase. In H. pylori, this helicase, designated RhpA, forms a minimal RNA degradosome together with the essential RNase, RNase J, a major player in the control of RNA decay. Here, we used H. pylori as a model organism with a sole DEAD-box helicase and investigated the role of this helicase in H. pylori physiology, ribosome assembly, and during in vivo colonization. Our data showed that RhpA is dispensable for growth at 37°C but crucial at 33°C, suggesting an essential role of the helicase in cold adaptation. Moreover, we found that a ΔrhpA mutant was impaired in motility and deficient in colonization of the mouse model. RhpA is involved in the maturation of 16S rRNA at 37°C and is associated with translating ribosomes. At 33°C, RhpA is, in addition, recruited to individual ribosomal subunits. Finally, via its role in the RNA degradosome, RhpA directs the regulation of the expression of its partner, RNase J. RhpA is thus a multifunctional enzyme that, in H. pylori, plays a central role in gene regulation and in the control of virulence.IMPORTANCE We present the results of our study on the role of RhpA, the sole DEAD-box RNA helicase encoded by the major gastric pathogen Helicobacter pylori We observed that all the Helicobacter species possess such a sole helicase, in contrast to most free-living bacteria. RhpA is not essential for growth of H. pylori under normal conditions. However, deletion of rhpA leads to a motility defect and to total inhibition of the ability of H. pylori to colonize a mouse model. We also demonstrated that this helicase encompasses most of the functions of its specialized orthologs described so far. We found that RhpA is a key element of the bacterial adaptation to colder temperatures and plays a minor role in ribosome biogenesis. Finally, RhpA regulates transcription of the rnj gene encoding RNase J, its essential partner in the minimal H. pylori RNA degradosome, and thus plays a crucial role in the control of RNA decay.

Accuracy of the Ultra-Rapid Urease Test for diagnosis of Helicobacter pylori infection / Exactitud del test Ultra-Rapido de la Ureasa para el Diagnóstico de la infección por Helicobacter pylori

Background: Rapid Urease Test (RUT) is a simple, cheap and relatively fast method for diagnosing Helicobacter pylori infection. It is therefore the preferred method used for patients undergoing gastroscopy. Most kits require 24h to give results. The new Ultra-Rapid Urease Test (URUT) kit by Biohit(R) requires less than 1h. Objective: To determine URUT's diagnostic accuracy. Method: Prospective, blind, multi-centre study involving dyspeptic patients. One corpus biopsy and three antral biopsies were obtained during gastroscopy for standard histological analysis, RUT and URUT. The URUT result was checked after 1min, 5min, 30min and 60min and the RUT was checked over the course of 24h. Histology was used as the gold standard test. Results: 144 patients were included, 68% female, with a mean age of 49 years old; 50% were H. pyloripositive. RUT and URUT diagnoses were correct in 85.9% and 90% of the cases, respectively. The mean waiting time for a positive RUT result was 6h. The sensitivity, specificity, and positive and negative predictive values for RUT were, respectively, 82%, 90%, 89% and 84%. The URUT's results were similar (85%, 94%, 94% and 87%). These figures improved when patients taking PPIs were excluded (RUT: 86%, 91%, 93% and 83%; URUT: 91%, 94%, 96% and 89%). No statistically significant differences were found when comparing RUT and URUT distributions of correct diagnoses (McNemar's Test, p=0.3) but there was a tendency towards better results with the URUT. Conclusion: The URUT is equivalent to (or slightly better than) the traditional RUT in diagnosing H. pyloriinfection, and provides results in less than an hour (AU)

Introducción: El test de la ureasa (TRU) es un método simple, barato y relativamente rápido para el diagnóstico de la infección por Helicobacter pylori (H. pylori). Por tanto, es el método de elección en pacientes sometidos a gastroscopia. La mayoría de los kits requieren 24 h para obtener un resultado. En nuevo test ultrarrápido de la ureasa (TURU) de Biohit requiere menos de una hora. Objetivo: Determinar la exactitud diagnóstica del TURU. Método: Estudio multicéntrico, prospectivo y ciego, en el que se incluyó a pacientes dispépticos. Se obtuvieron 3 biopsias de antro y una de corpus durante la gastroscopia para análisis histológico estándar, TRU y TURU. El resultado del TURU se comprobó a los 1, 5, 30 y 60 min, mientras que el TRU se evaluó a lo largo de 24 h. La histología se utilizó como patrón oro. Resultados: Se incluyó a 144 pacientes, 68% mujeres, edad media 49 años, el 50% fueron positivos para H. pylori. TRU y TURU diagnosticaron correctamente el 85,9% y 90,0% de los casos, respectivamente. La duración media de espera para un resultado positivo del TRU fue 6 h. La sensibilidad, la especificidad y los valores predictivos negativo y positivo para el TRU fueron, respectivamente, del 82, el 90, el 89 y el 84%. Los resultados del TURU fueron equivalentes (el 85, el 94, el 94 y el 87%). Estos resultados mejoraron al excluir los pacientes que tomaban IBP (TRU: 86, 91, 93 y 83%; TURU: 91, 94, 96 y 89%). La comparación de distribución de diagnósticos correctos entre TRU y TURU no encontró diferencias estadísticamente significativas (test de McNemar p=0,3) pero existe una tendencia a mejores resultados con el TURU. Conclusión: El TURU es equivalente (o algo superior) al TRU tradicional en el diagnóstico de la infección por H. pylori y obtiene los resultados en menos de una hora (AU)

Ahorro en los recursos en relación con la utilización del test de ureasa ultrarrápido / Saving resources in relation to ultrafast urease test

No disponible

Helicobacter PyloriAssociation with Expression of CDX2 in Intestinal Metaplasia.

OBJECTIVE: To assess whether helicobacter pylori was associated with CDX2 expression in intestinal metaplasia, atrophic gastritis, dysplasia and gastric cancer. STUDY DESIGN: Cross-sectional study. PLACE AND DURATION OF STUDY: Department of Pathology, The First Hospital of Jilin University, Changchun, China, from August 2016 to January 2017. METHODOLOGY: CDX2 expression was evaluated in 62 gastric antral biopsies; including 32 cases of intestinal metaplasia (IM) and 10 cases each of atrophic gastritis (AG), dysplasia and gastric cancer. Hematoxylin and Eosin staining was used to detect H.pyloriand immunohistochemistry was performed to observe CDX2 in the samples. RESULTS: Of the 62 patients inducted in the study, CDX2 expression was observed in 53 (85.5%). Mean age of these patients was 59 years (s.d.:11.3; range: 38-87) and included 32 males (60.38%) and 21 females (39.62%). However, age and gender were not found to be significantly associated with expression of CDX2 (p >0.05). CDX2 was very frequently expressed in individuals with IM (90.6%). Most of the patients with IM were males (17/29) as compared to females (12/29). However, the difference was not statistically significant (p=0.568). Only 4 out of 29 IM CDX2 positive specimens tested positive for H.pylori(p=1.0). CONCLUSION: CDX2 is highly expressed along the atrophic gastritis-metaplasia-dysplasia-cancer sequential. Though CDX2 expression is quite dominant in IM, but its expression is not associated with H.pyloriinfection.