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1.
Int J Mol Sci ; 22(4)2021 Feb 12.
Artículo en Inglés | MEDLINE | ID: mdl-33673347

RESUMEN

Gastric cancer is considered one of the most common malignancies in humans and Helicobacter pylori infection is the major environmental risk factor of gastric cancer development. Given the high spread of this bacterium whose infection is mostly asymptomatic, H. pylori colonization persists for a long time, becoming chronic and predisposing to malignant transformation. The first defensive barrier from bacterial infection is constituted by the gastric mucosa that secretes several protective factors, among which is the trefoil factor 1 (TFF1), that, as mucin 5AC, binds the bacterium. Even if the protective role of TFF1 is well-documented, the molecular mechanisms that confer a beneficial function to the interaction among TFF1 and H. pylori remain still unclear. Here we analyze the effects of this interaction on H. pylori at morphological and molecular levels by means of microscopic observation, chemiotaxis and motility assays and real-time PCR analysis. Our results show that TFF1 favors aggregation of H. pylori and significantly slows down the motility of the bacterium across the mucus. Such aggregates significantly reduce both flgE and flaB gene transcription compared with bacteria not incubated with TFF1. Finally, our results suggest that the interaction between TFF1 and the bacterium may explain the frequent persistence of H. pylori in the human host without inducing disease.


Asunto(s)
Proteínas Bacterianas/metabolismo , Flagelina/metabolismo , Mucosa Gástrica , Helicobacter pylori/metabolismo , Factor Trefoil-1/metabolismo , Mucosa Gástrica/metabolismo , Mucosa Gástrica/microbiología , Células HT29 , Humanos
2.
Life Sci ; 267: 118921, 2021 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-33358913

RESUMEN

AIMS: Helicobacter pylori (Hp) infection plays an important role in the development of gastric cancer. Hp can secrete gamma-glutamyltransferase (GGT), however, the impact of GGT of Hp on the human gastric cells is not clear. Although it has been demonstrated that ten-eleven translocation 1 (TET1) is overexpressed in gastric cancer, the relationship between the GGT of Hp and TET1 has not been studied. The aim of this study was to explore the relationship between GGT and TET1, and the role of TET1 in the development of gastric cancer induced by Hp was also explored. MATERIALS AND METHODS: The correlation between TET1 and prognosis of gastric adenoma cancer was analyzed by bioinformatics. The GGT gene of Hp26695 was knocked out by electroporation with plasmid to construct the GGT knockout strain of Hp (Hp-KS-1). The shTET1 lentivirus transfected GES-1, MGC-803 and SGC-7901 cell lines were constructed. The biological characteristics of the three kind of cells were detected. KEY FINDINGS: TET1 was overexpressed in gastric tissues of Hp infected patients and mice. Bioinformatics analysis showed that in patients with gastric cancer, higher TET1 expression would result in poorer prognosis. The GGT gene of Hp can lead to overexpression of TET1 in GES-1, MGC-803 and SGC-7901 cells, along with the activation of Wnt/ß-catenin signaling pathway, and then promoting tumorigenesis. After silencing TET1, the Wnt/ß-catenin signaling pathway which was activated by GGT of Hp was inhibited. SIGNIFICANCE: GGT of Helicobacter pylori can promote gastric carcinogenesis by activating Wnt/ß-catenin signaling pathway trough up-regulating TET1.


Asunto(s)
Infecciones por Helicobacter/microbiología , Helicobacter pylori/enzimología , Helicobacter pylori/genética , Oxigenasas de Función Mixta/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Neoplasias Gástricas/microbiología , Vía de Señalización Wnt , gamma-Glutamiltransferasa/genética , Pólipos Adenomatosos/metabolismo , Animales , Línea Celular Tumoral , Movimiento Celular/fisiología , Proliferación Celular/fisiología , Transformación Celular Neoplásica , Mucosa Gástrica/metabolismo , Infecciones por Helicobacter/metabolismo , Infecciones por Helicobacter/patología , Helicobacter pylori/metabolismo , Humanos , Masculino , Ratones , Ratones Desnudos , Oxigenasas de Función Mixta/genética , Proteínas Proto-Oncogénicas/genética , Neoplasias Gástricas/metabolismo , Activación Transcripcional , beta Catenina/metabolismo , gamma-Glutamiltransferasa/metabolismo
3.
Int J Mol Sci ; 21(24)2020 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-33327555

RESUMEN

Helicobacter pylori is a bacterium known mainly of its ability to cause persistent inflammations of the human stomach, resulting in peptic ulcer diseases and gastric cancers. Continuous exposure of this bacterium to antibiotics has resulted in high detection of multidrug-resistant strains and difficulties in obtaining a therapeutic effect. The purpose of the present study was to determine the usability of bacterial cellulose (BC) chemisorbed with 3-bromopyruvate (3-BP) or sertraline (SER) to act against lawn H. pylori biofilms. The characterization of BC carriers was made using a N2 adsorption/desorption analysis, tensile strength test, and scanning electron microscopy (SEM) observations. Determination of an antimicrobial activity was performed using a modified disk-diffusion method and a self-designed method of testing antibacterial activity against biofilm microbial forms. In addition, bacterial morphology was checked by SEM. It was found that BC disks were characterized by a high cross-linking and shear/stretch resistance. Growth inhibition zones for BC disks chemisorbed with 2 mg of SER or 3-BP were equal to 26.5-27.5 mm and 27-30 mm, respectively. The viability of lawn biofilm H. pylori cells after a 4-h incubation with 2 mg SER or 3-BP chemisorbed on BC disks was ≥4 log lower, suggesting their antibacterial effect. SEM observations showed a number of morphostructural changes in H. pylori cells exposed to these substances. Concluding, SER and 3-BP chemisorbed on BC carriers presented a promising antibacterial activity against biofilm H. pylori cells in in vitro conditions.


Asunto(s)
Celulosa/metabolismo , Piruvatos/metabolismo , Sertralina/metabolismo , Biopelículas/crecimiento & desarrollo , Helicobacter pylori/crecimiento & desarrollo , Helicobacter pylori/metabolismo , Helicobacter pylori/ultraestructura , Pruebas de Sensibilidad Microbiana
4.
Sci Rep ; 10(1): 18149, 2020 10 23.
Artículo en Inglés | MEDLINE | ID: mdl-33097791

RESUMEN

Antigens displayed on self-assembling nanoparticles can stimulate strong immune responses and have been playing an increasingly prominent role in structure-based vaccines. However, the development of such immunogens is often complicated by inefficiencies in their production. To alleviate this issue, we developed a plug-and-play platform using the spontaneous isopeptide-bond formation of the SpyTag:SpyCatcher system to display trimeric antigens on self-assembling nanoparticles, including the 60-subunit Aquifex aeolicus lumazine synthase (LuS) and the 24-subunit Helicobacter pylori ferritin. LuS and ferritin coupled to SpyTag expressed well in a mammalian expression system when an N-linked glycan was added to the nanoparticle surface. The respiratory syncytial virus fusion (F) glycoprotein trimer-stabilized in the prefusion conformation and fused with SpyCatcher-could be efficiently conjugated to LuS-SpyTag or ferritin-SpyTag, enabling multivalent display of F trimers with prefusion antigenicity. Similarly, F-glycoprotein trimers from human parainfluenza virus-type 3 and spike-glycoprotein trimers from SARS-CoV-2 could be displayed on LuS nanoparticles with decent yield and antigenicity. Notably, murine vaccination with 0.08 µg of SARS-CoV-2 spike-LuS nanoparticle elicited similar neutralizing responses as 2.0 µg of spike, which was ~ 25-fold higher on a weight-per-weight basis. The versatile platform described here thus allows for multivalent plug-and-play presentation on self-assembling nanoparticles of trimeric viral antigens, with SARS-CoV-2 spike-LuS nanoparticles inducing particularly potent neutralizing responses.


Asunto(s)
Antígenos/inmunología , Betacoronavirus/metabolismo , Nanopartículas/química , Glicoproteína de la Espiga del Coronavirus/inmunología , Animales , Anticuerpos Neutralizantes/inmunología , Antígenos/genética , Antígenos/metabolismo , Bacterias/enzimología , Proteínas Bacterianas/genética , Betacoronavirus/aislamiento & purificación , Infecciones por Coronavirus , Ferritinas/genética , Helicobacter pylori/metabolismo , Humanos , Ratones , Complejos Multienzimáticos/genética , Pruebas de Neutralización , Pandemias , Neumonía Viral , Multimerización de Proteína , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/química , Proteínas Recombinantes/inmunología , Glicoproteína de la Espiga del Coronavirus/genética , Glicoproteína de la Espiga del Coronavirus/metabolismo , Propiedades de Superficie
5.
Nat Commun ; 11(1): 5117, 2020 10 09.
Artículo en Inglés | MEDLINE | ID: mdl-33037203

RESUMEN

Exposure of gastric epithelial cells to the bacterial carcinogen Helicobacter pylori causes DNA double strand breaks. Here, we show that H. pylori-induced DNA damage occurs co-transcriptionally in S-phase cells that activate NF-κB signaling upon innate immune recognition of the lipopolysaccharide biosynthetic intermediate ß-ADP-heptose by the ALPK1/TIFA signaling pathway. DNA damage depends on the bi-functional RfaE enzyme and the Cag pathogenicity island of H. pylori, is accompanied by replication fork stalling and can be observed also in primary cells derived from gastric organoids. Importantly, H. pylori-induced replication stress and DNA damage depend on the presence of co-transcriptional RNA/DNA hybrids (R-loops) that form in infected cells during S-phase as a consequence of ß-ADP-heptose/ ALPK1/TIFA/NF-κB signaling. H. pylori resides in close proximity to S-phase cells in the gastric mucosa of gastritis patients. Taken together, our results link bacterial infection and NF-κB-driven innate immune responses to R-loop-dependent replication stress and DNA damage.


Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/metabolismo , Helicobacter pylori/patogenicidad , FN-kappa B/metabolismo , Proteínas Quinasas/metabolismo , Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Bacterianas/metabolismo , Línea Celular Tumoral , ADN/química , ADN/genética , Daño del ADN , Replicación del ADN/efectos de los fármacos , Floxuridina , Glicosiltransferasas/metabolismo , Infecciones por Helicobacter/metabolismo , Infecciones por Helicobacter/microbiología , Helicobacter pylori/metabolismo , Interacciones Huésped-Patógeno/fisiología , Humanos , Lipopolisacáridos/metabolismo , Mutación , FN-kappa B/genética , Proteínas Quinasas/genética , Especies Reactivas de Oxígeno/metabolismo , Neoplasias Gástricas/genética , Neoplasias Gástricas/microbiología , Neoplasias Gástricas/patología
6.
PLoS One ; 15(9): e0238944, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32966303

RESUMEN

BACKGROUND AND AIMS: Patients that have failed therapy for Helicobacter pylori (H. pylori) infection are incompletely characterized. The aim of this study was to characterize a H. pylori treatment resistant cohort compared to the cohorts of newly diagnosed, earlier eradicated and non-infected. MATERIAL AND METHODS: Patients were selected from routine referrals to the Endoscopy units at three different Norwegian hospitals. In all four cohorts, gastric biopsies were scored according to the Sydney classification, and symptoms according to the Gastrointestinal Symptom Rating Scale score, including sub-scores for upper gastrointestinal symptoms and functional bowel symptoms. Patients in the H. pylori resistant group were treated with a triple therapy regimen that consisted of levofloxacin, amoxicillin and a proton pump inhibitor. RESULTS: We included 185 patients, 42 H. pylori treatment resistant, 50 newly diagnosed, 61 previously H. pylori eradicated and 32 never infected. The treatment-resistant cohort had higher scores for upper gastrointestinal symptoms and functional bowel symptoms compared to the other groups except for the group being never H. pylori infected. The H. pylori resistant patients had lower Sydney scores than patients with newly diagnosed H. pylori infection. The triple combination showed a high efficacy of 91% to eradicate H. pylori. CONCLUSIONS: Patients with treatment-resistant H. pylori infection had more gastrointestinal symptoms, but a lower Sydney score than patients with newly diagnosed infection. A treatment regimen including levofloxacin showed a high efficacy in eradicating H. pylori in patients that previously had failed eradication treatment.


Asunto(s)
Farmacorresistencia Bacteriana/efectos de los fármacos , Infecciones por Helicobacter/tratamiento farmacológico , Helicobacter pylori/efectos de los fármacos , Anciano , Amoxicilina/uso terapéutico , Antibacterianos/farmacología , Quimioterapia Combinada , Femenino , Infecciones por Helicobacter/metabolismo , Infecciones por Helicobacter/fisiopatología , Helicobacter pylori/metabolismo , Helicobacter pylori/patogenicidad , Humanos , Levofloxacino/uso terapéutico , Masculino , Persona de Mediana Edad , Inhibidores de la Bomba de Protones/uso terapéutico
7.
Oncogene ; 39(17): 3427-3442, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-32123313

RESUMEN

Gastric cancer (GC) is one of the leading causes of cancer-related death worldwide. The role of the microorganisms in gastric tumorigenesis attracts much attention in recent years. These microorganisms include bacteria, virus, and fungi. Among them, Helicobacter pylori (H. pylori) infection is by far the most important risk factor for GC development, with special reference to the early-onset cases. H. pylori targets multiple cellular components by utilizing various virulence factors to modulate the host proliferation, apoptosis, migration, and inflammatory response. Epstein-Barr virus (EBV) serves as another major risk factor in gastric carcinogenesis. The virus protein, EBER noncoding RNA, and EBV miRNAs contribute to the tumorigenesis by modulating host genome methylation and gene expression. In this review, we summarized the related reports about the colonized microorganism in the stomach and discussed their specific roles in gastric tumorigenesis. Meanwhile, we highlighted the therapeutic significance of eradicating the microorganisms in GC treatment.


Asunto(s)
Carcinogénesis , Infecciones por Virus de Epstein-Barr , Genoma Humano , Infecciones por Helicobacter , Helicobacter pylori , Herpesvirus Humano 4 , Neoplasias Gástricas , Carcinogénesis/genética , Carcinogénesis/metabolismo , Carcinogénesis/patología , Infecciones por Virus de Epstein-Barr/genética , Infecciones por Virus de Epstein-Barr/metabolismo , Infecciones por Virus de Epstein-Barr/microbiología , Infecciones por Helicobacter/genética , Infecciones por Helicobacter/metabolismo , Infecciones por Helicobacter/virología , Helicobacter pylori/genética , Helicobacter pylori/metabolismo , Herpesvirus Humano 4/genética , Herpesvirus Humano 4/metabolismo , Humanos , Neoplasias Gástricas/genética , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/microbiología , Neoplasias Gástricas/virología
8.
Cancer Sci ; 111(5): 1596-1606, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32198795

RESUMEN

Chronic infection with Helicobacter pylori cagA-positive strains is causally associated with the development of gastric diseases, most notably gastric cancer. The cagA-encoded CagA protein, which is injected into gastric epithelial cells by bacterial type IV secretion, undergoes tyrosine phosphorylation at the Glu-Pro-Ile-Tyr-Ala (EPIYA) segments (EPIYA-A, EPIYA-B, EPIYA-C, and EPIYA-D), which are present in various numbers and combinations in its C-terminal polymorphic region, thereby enabling CagA to promiscuously interact with SH2 domain-containing host cell proteins, including the prooncogenic SH2 domain-containing protein tyrosine phosphatase 2 (SHP2). Perturbation of host protein functions by aberrant complex formation with CagA has been considered to contribute to the development of gastric cancer. Here we show that SHIP2, an SH2 domain-containing phosphatidylinositol 5'-phosphatase, is a hitherto undiscovered CagA-binding host protein. Similar to SHP2, SHIP2 binds to the Western CagA-specific EPIYA-C segment or East Asian CagA-specific EPIYA-D segment through the SH2 domain in a tyrosine phosphorylation-dependent manner. In contrast to the case of SHP2, however, SHIP2 binds more strongly to EPIYA-C than to EPIYA-D. Interaction with CagA tethers SHIP2 to the plasma membrane, where it mediates production of phosphatidylinositol 3,4-diphosphate [PI(3,4)P2 ]. The CagA-SHIP2 interaction also potentiates the morphogenetic activity of CagA, which is caused by CagA-deregulated SHP2. This study indicates that initially delivered CagA interacts with SHIP2 and thereby strengthens H. pylori-host cell attachment by altering membrane phosphatidylinositol compositions, which potentiates subsequent delivery of CagA that binds to and thereby deregulates the prooncogenic phosphatase SHP2.


Asunto(s)
Antígenos Bacterianos/metabolismo , Proteínas Bacterianas/metabolismo , Células Epiteliales/metabolismo , Mucosa Gástrica/metabolismo , Infecciones por Helicobacter/metabolismo , Helicobacter pylori/metabolismo , Fosfatidilinositol-3,4,5-Trifosfato 5-Fosfatasas/metabolismo , Secuencias de Aminoácidos , Animales , Antígenos Bacterianos/química , Antígenos Bacterianos/genética , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Línea Celular , Membrana Celular/metabolismo , Células Epiteliales/microbiología , Células Epiteliales/patología , Transición Epitelial-Mesenquimal , Mucosa Gástrica/microbiología , Mucosa Gástrica/patología , Infecciones por Helicobacter/microbiología , Helicobacter pylori/genética , Humanos , Fosfatos de Fosfatidilinositol/metabolismo , Fosfatidilinositol-3,4,5-Trifosfato 5-Fosfatasas/química , Fosfatidilinositol-3,4,5-Trifosfato 5-Fosfatasas/genética , Fosforilación , Unión Proteica , Transporte de Proteínas , Proteína Tirosina Fosfatasa no Receptora Tipo 11/química , Proteína Tirosina Fosfatasa no Receptora Tipo 11/metabolismo , Dominios Homologos src
9.
Biochemistry (Mosc) ; 85(2): 234-240, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-32093599

RESUMEN

Helicobacter pylori is an important human pathogen that causes gastritis, gastric and duodenal ulcers, and gastric cancer. O-polysaccharides of H. pylori lipopolysaccharide (LPS) are composed of (ß1→3)-poly(N-acetyllactosamine) (polyLacNAc) decorated with multiple α-L-fucose residues. In many strains, their terminal LacNAc units are mono- or di-fucosylated to mimic Lewis X (Lex) and/or Lewis Y (Ley) oligosaccharides. The studies in rhesus macaques as a model of human infection by H. pylori showed that this bacterium adapts to the host during colonization by expressing host Lewis antigens. Here, we characterized LPS from H. pylori strains used in the previous study, including the parental J166 strain and the three derivatives (98-149, 98-169, and 98-181) isolated from rhesus macaques after long-term colonization. Chemical and NMR spectroscopic analyses of the LPS showed that the parent strain expressed Lex, Ley, and H type 1 terminal oligosaccharide units. The daughter strains were similar to the parental one in the presence of the same LPS core and fucosylated polyLacNAc chain of the same length but differed in the terminal oligosaccharide units. These were Lex in the isolates 98-149 and 98-169, which corresponded to the Lea phenotype of the host animals, and Ley was found in the 98-181 isolate from the macaque characterized by the Leb phenotype. As Lea and Leb are isomers of Lex and Ley, respectively, the observed correlation confirmed adaptation of the expression of terminal oligosaccharide units in H. pylori strains to the properties of the host gastric mucosa. The 98-181 strain also acquired glucosylation of the polyLacNAc chain and was distinguished by a lower expression of fucosylated internal LacNAc units (internal Lex) as a result of decoration of polyLacNAc with ß-glucopyranose, which may also play a role in the bacterial adaptation.


Asunto(s)
Helicobacter pylori/química , Lipopolisacáridos/química , Macaca mulatta/microbiología , Oligosacáridos/genética , Polisacáridos/metabolismo , Animales , Glicosilación , Helicobacter pylori/metabolismo , Lipopolisacáridos/aislamiento & purificación , Lipopolisacáridos/metabolismo , Oligosacáridos/análisis , Oligosacáridos/metabolismo , Fenotipo , Polisacáridos/química
10.
J Med Microbiol ; 69(2): 218-227, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-32011229

RESUMEN

Introduction. Gastric cancer is a health disparity in the Alaska Native people. The incidence of Helicobacter pylori infection, a risk factor for non-cardia gastric adenocarcinoma, is also high. Gastric cancer is partially associated with the virulence of the infecting strain.Aim. To genotype the vacA s, m and i and cag pathogenicity island (cagPAI) genes in H. pylori from Alaskans and investigate associations with gastropathy.Methodology. We enrolled patients with gastritis, peptic ulcer disease (PUD) and intestinal metaplasia (IM) in 1998-2005 and patients with gastric cancer in 2011-2013. Gastric biopsies were collected and cultured and PCR was performed to detect the presence of the right and left ends of the cagPAI, the cagA, cagE, cagT and virD4 genes and to genotype the vacA s, m and i regions.Results. We recruited 263 people; 22 (8 %) had no/mild gastritis, 121 (46 %) had moderate gastritis, 40 (15%) had severe gastritis, 38 (14 %) had PUD, 30 (11 %) had IM and 12 (5 %) had gastric cancer. H. pylori isolates from 150 (57%) people had an intact cagPAI; those were associated with a more severe gastropathy (P≤0.02 for all comparisons). H. pylori isolates from 77 % of people had either the vacA s1/i1/m1 (40 %; 94/234) or s2/i2/m2 (37 %; 86/234) genotype. vacA s1/i1/m1 was associated with a more severe gastropathy (P≤0.03 for all comparisons).Conclusions. In this population with high rates of gastric cancer, we found that just over half of the H. pylori contained an intact cagPAI and 40 % had the vacA s1/i1/m1 genotype. Infection with these strains was associated with a more severe gastropathy.


Asunto(s)
Proteínas Bacterianas/genética , Islas Genómicas , Infecciones por Helicobacter/microbiología , Helicobacter pylori/genética , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Alaska , Proteínas Bacterianas/metabolismo , Femenino , Helicobacter pylori/aislamiento & purificación , Helicobacter pylori/metabolismo , Humanos , Masculino , Persona de Mediana Edad , Úlcera Péptica/microbiología , Neoplasias Gástricas/microbiología , Factores de Virulencia/genética , Factores de Virulencia/metabolismo , Adulto Joven
11.
J Basic Microbiol ; 60(3): 207-215, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31960983

RESUMEN

The treatment of Helicobacter pylori usually fails due to their ability to form biofilms and resistance to antibiotics. This might potentially lead to gastric carcinoma and mucosa-associated lymphoid tissue lymphoma. In the present study, we elucidate the potential role of N-acylhomoserine lactonase stabilized silver nanoparticles (AiiA-AgNPs) in treating biofilms produced by H. pylori. AiiA-AgNPs inhibited quorum sensing (QS) by degradation of QS molecules, thereby reducing biofilm formation, urease production, and altering cell surface hydrophobicity of H. pylori. AiiA-AgNPs showed no cytotoxic effects on RAW 264.7 macrophages at the effective concentration (1-5 µM) of antibiofilm activity. In addition, AiiA-AgNP in high concentration (80-100 µM) exhibited cytotoxicity against HCT-15 carcinoma cells, depicting its therapeutic role in treating cancer.


Asunto(s)
Antibacterianos/farmacología , Biopelículas/efectos de los fármacos , Hidrolasas de Éster Carboxílico/farmacología , Helicobacter pylori/efectos de los fármacos , Percepción de Quorum/efectos de los fármacos , Plata/farmacología , Animales , Antibacterianos/química , Antineoplásicos/química , Antineoplásicos/farmacología , Biopelículas/crecimiento & desarrollo , Hidrolasas de Éster Carboxílico/química , Línea Celular Tumoral , Membrana Celular/química , Membrana Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Helicobacter pylori/metabolismo , Humanos , Interacciones Hidrofóbicas e Hidrofílicas/efectos de los fármacos , Nanopartículas del Metal/química , Ratones , Células RAW 264.7 , Plata/química , Ureasa/metabolismo
12.
Proc Natl Acad Sci U S A ; 117(5): 2645-2655, 2020 02 04.
Artículo en Inglés | MEDLINE | ID: mdl-31964836

RESUMEN

The main risk factor for stomach cancer, the third most common cause of cancer death worldwide, is infection with Helicobacter pylori bacterial strains that inject cytotoxin-associated gene A (CagA). As the first described bacterial oncoprotein, CagA causes gastric epithelial cell transformation by promoting an epithelial-to-mesenchymal transition (EMT)-like phenotype that disrupts junctions and enhances motility and invasiveness of the infected cells. However, the mechanism by which CagA disrupts gastric epithelial cell polarity to achieve its oncogenicity is not fully understood. Here we found that the apoptosis-stimulating protein of p53 2 (ASPP2), a host tumor suppressor and an important CagA target, contributes to the survival of cagA-positive H. pylori in the lumen of infected gastric organoids. Mechanistically, the CagA-ASPP2 interaction is a key event that promotes remodeling of the partitioning-defective (PAR) polarity complex and leads to loss of cell polarity of infected cells. Blockade of cagA-positive H. pylori ASPP2 signaling by inhibitors of the EGFR (epidermal growth factor receptor) signaling pathway-identified by a high-content imaging screen-or by a CagA-binding ASPP2 peptide, prevents the loss of cell polarity and decreases the survival of H. pylori in infected organoids. These findings suggest that maintaining the host cell-polarity barrier would reduce the detrimental consequences of infection by pathogenic bacteria, such as H. pylori, that exploit the epithelial mucosal surface to colonize the host environment.


Asunto(s)
Antígenos Bacterianos/metabolismo , Proteínas Reguladoras de la Apoptosis/metabolismo , Proteínas Bacterianas/metabolismo , Células Epiteliales/citología , Infecciones por Helicobacter/metabolismo , Helicobacter pylori/metabolismo , Organoides/microbiología , Antígenos Bacterianos/genética , Proteínas Reguladoras de la Apoptosis/genética , Proteínas Bacterianas/genética , Células Epiteliales/metabolismo , Células Epiteliales/microbiología , Infecciones por Helicobacter/genética , Infecciones por Helicobacter/microbiología , Helicobacter pylori/genética , Helicobacter pylori/crecimiento & desarrollo , Interacciones Huésped-Patógeno , Humanos , Organoides/metabolismo , Unión Proteica , Estómago/microbiología
13.
Chem Commun (Camb) ; 56(3): 344-347, 2020 Jan 02.
Artículo en Inglés | MEDLINE | ID: mdl-31808481

RESUMEN

Exploiting synergistic remote participation effects of acyl groups at the O3 and O6 positions was key to the complete α-selectivity during the total synthesis of the unique (1 → 2)- and (1 → 3)-linked α-oligoglucosides from the Helicobacter pylori O2 O-antigen. Acyl remote participation and solvent effects were found to counteract during α-stereoselective glucosylations for the first time. The resulting antigen is a lead for the development of a carbohydrate-conjugate vaccine.


Asunto(s)
Helicobacter pylori/metabolismo , Antígenos O/química , Oligosacáridos/síntesis química , Oligosacáridos/química , Serogrupo , Solventes/química , Estereoisomerismo , Vacunas Conjugadas/química
14.
Autophagy ; 16(1): 169-170, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-31599196

RESUMEN

Inhibition of host macroautophagy/autophagy is one of the strategies used by several intracellular pathogens, including H. pylori, to escape killing. Here we discuss our recent work that revealed the novel mechanism by which the vacuolating cytotoxin A (VacA) produced by H. pylori inhibits lysosomal and autophagic killing. We discovered that VacA impairs the activity of the lysosomal calcium channel MCOLN1/TRPML1 leading to the formation of enlarged, dysfunctional lysosomes and autophagosomes that serve as an intracellular niche, which allows the bacteria to escape eradication therapy.


Asunto(s)
Antibacterianos/farmacología , Autofagia/efectos de los fármacos , Infecciones por Helicobacter/tratamiento farmacológico , Lisosomas/efectos de los fármacos , Autofagosomas/metabolismo , Helicobacter pylori/metabolismo , Humanos , Lisosomas/metabolismo
15.
Ann N Y Acad Sci ; 1465(1): 10-28, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-31642532

RESUMEN

Nitric oxide (NO), a small molecule generated ubiquitously, targets a plethora of tissues to regulate both physiological and pathophysiological functions. NO overproduction, stimulated by microenvironmental conditions, is the main component that dysregulates the tight balance between its beneficial and damaging roles in ocular homeostasis. Considering the protective functions of NO against glaucoma, its endogenous release facilitates aqueous humor drainage and regulates ocular blood flow, maintaining a normal intraocular pressure. NO overproduction generates free radicals, such as peroxynitrite, which induce a vicious circle of vascular disharmony and dysregulation, transient ischemia, nitrosative stress, neuronal degeneration, and permanent glaucomatic injury. Helicobacter pylori (Hp) is considered a burdening factor of glaucoma. NO overproduction and possible systematic dispersion in Hp infection (Hp-I) could suggest a potential pathophysiological bridge between these conditions. In this review, we aim to elucidate the role of NO in glaucoma with respect to Hp-I, with the aim to stimulate further studies.


Asunto(s)
Glaucoma/metabolismo , Infecciones por Helicobacter/metabolismo , Helicobacter pylori/metabolismo , Óxido Nítrico/metabolismo , Ojo/metabolismo , Ojo/patología , Glaucoma/microbiología , Glaucoma/patología , Infecciones por Helicobacter/microbiología , Infecciones por Helicobacter/patología , Helicobacter pylori/patogenicidad , Humanos , Estrés Nitrosativo
16.
Helicobacter ; 25(1): e12665, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31657090

RESUMEN

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.


Asunto(s)
Antígenos Bacterianos/metabolismo , Proteínas Bacterianas/metabolismo , Infecciones por Helicobacter/enzimología , Helicobacter pylori/metabolismo , Ribonucleoproteína Nuclear Heterogénea D0/metabolismo , Hormonas Peptídicas/metabolismo , Neoplasias Gástricas/metabolismo , Antígenos Bacterianos/genética , Proteínas Bacterianas/genética , Línea Celular Tumoral , Quinasas MAP Reguladas por Señal Extracelular/genética , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Mucosa Gástrica/metabolismo , Mucosa Gástrica/patología , Infecciones por Helicobacter/genética , Infecciones por Helicobacter/microbiología , Infecciones por Helicobacter/patología , Helicobacter pylori/genética , Ribonucleoproteína Nuclear Heterogénea D0/genética , Interacciones Huésped-Patógeno , Humanos , Hormonas Peptídicas/genética , Fosforilación , Neoplasias Gástricas/genética , Neoplasias Gástricas/microbiología , Neoplasias Gástricas/patología
17.
Mol Microbiol ; 113(2): 338-355, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-31715026

RESUMEN

The main roles of the DnaA protein are to bind the origin of chromosome replication (oriC), to unwind DNA and to provide a hub for the step-wise assembly of a replisome. DnaA is composed of four domains, with each playing a distinct functional role in the orisome assembly. Out of the four domains, the role of domain I is the least understood and appears to be the most species-specific. To better characterise Helicobacter pylori DnaA domain I, we have constructed a series of DnaA variants and studied their interactions with H. pylori bipartite oriC. We show that domain I is responsible for the stabilisation and organisation of DnaA-oriC complexes and provides cooperativity in DnaA-DNA interactions. Domain I mediates cross-interactions between oriC subcomplexes, which indicates that domain I is important for long-distance DnaA interactions and is essential for orisosme assembly on bipartite origins. HobA, which interacts with domain I, increases the DnaA binding to bipartite oriC; however, it does not stimulate but rather inhibits DNA unwinding. This suggests that HobA helps DnaA to bind oriC, but an unknown factor triggers DNA unwinding. Together, our results indicate that domain I self-interaction is important for the DnaA assembly on bipartite H. pylori oriC.


Asunto(s)
Proteínas Bacterianas , Cromosomas Bacterianos/metabolismo , Proteínas de Unión al ADN , Helicobacter pylori , Complejo de Reconocimiento del Origen/metabolismo , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Cromosomas Bacterianos/química , Replicación del ADN , ADN Bacteriano/metabolismo , Proteínas de Unión al ADN/química , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Helicobacter pylori/genética , Helicobacter pylori/metabolismo , Nucleoproteínas/química , Nucleoproteínas/genética , Nucleoproteínas/metabolismo , Unión Proteica , Origen de Réplica
18.
Ann Lab Med ; 40(1): 68-71, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31432642

RESUMEN

Evaluation of diagnostic tests requires reference standards, which are often unavailable. Latent class analysis (LCA) can be used to evaluate diagnostic tests without reference standards, using a combination of observed and estimated results. Conditionally independent diagnostic tests for Helicobacter pylori infection are required. We used LCA to construct a reference standard and evaluate the capability of non-invasive tests (stool antigen test and serum antibody test) to diagnose H. pylori infection compared with the conventional method, where histology is the reference standard. A total of 96 healthy subjects with endoscopy histology results were enrolled from January to July 2016. Sensitivity and specificity were determined for the LCA approach (i.e., using a combination of three tests as the reference standard) and the conventional method. When LCA was used, sensitivity and specificity were 83.8% and 99.4% for histology, 80.0% and 81.9% for the stool antigen test, and 63.6% and 89.3% for the serum antibody test, respectively. When the conventional method was used, sensitivity and specificity were 75.8% and 71.1% for the stool antigen test and 77.7% and 60.7% for the serum antibody test, respectively. LCA can be applied to evaluate diagnostic tests that lack a reference standard.


Asunto(s)
Infecciones por Helicobacter/diagnóstico , Helicobacter pylori/aislamiento & purificación , Análisis de Clases Latentes , Anticuerpos Antibacterianos/sangre , Antígenos/análisis , Heces/química , Gastroscopía , Infecciones por Helicobacter/microbiología , Helicobacter pylori/inmunología , Helicobacter pylori/metabolismo , Humanos , Sensibilidad y Especificidad
19.
Chin J Integr Med ; 26(2): 122-129, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-28819779

RESUMEN

OBJECTIVE: To investigate the effects and possible mechanisms of action of Curcuma wenyujin Y. H. Chen et C. Ling n-Butyl alcohol extract (CWNAE) on repression of human gastric cancer (GC) AGS cell invasion induced by co-culturing with Helicobacter pylori (HP). METHODS: AGS cells were cultured with HP of positive or negative cytotoxin-associated gene A (CagA) and vacuolating cytotoxin gene A (VacA) expression (CagA+/- or VacA+/-) and divided into 5 group. Group A was cultured without HP as a control, Group B with HPCagA+VacA+, Group C with HPCagA-VacA-, Group D with HPCagA+VacA+ and CWNAE, and Group E with HPCagA-VacA- and CWNAE. Methylthiazolyldiphenyl-tetrazolium bromide (MTT) and tumor invasion assays, examinations of morphology and ultramicroscopic structures, quantitative real-time polymerase chain reaction and Western blots were performed to measure the effects and uncover the mechanisms behind these effects of HPCagA+VacA+ and CWNAE on the epithelial-mesenchymal transition (EMT) of AGS cells. RESULTS: The 10% inhibitory concentration of CWNAE against AGS cells after a 48 h incubation was 19.73±1.30 µg/mL. More AGS cells were elongated after co-culturing with HPCagA+VacA+ than after culturing with HPCagA-VacA-. In tumor invasion assays, HPCagA+VacA+ significantly enhanced the invasiveness of AGS cells compared to the other experimental groups (all P value <0.05), and this effect was inhibited by CWNAE. Treatment with CWNAE normalized tight junctions and reduced the number of pseudopodia of AGS cells co-cultured with HPCagA+VacA+. HPCagA+VacA+ up-regulated zincfinger ebox binding homeobox 1 (ZEB1) in AGS cells after co-culturing for 24 h. Expression of caudal type homeobox transcription factor (CDX-2) and claudin-2 was significantly increased by HPCagA+VacA+ (P<0.05), but not by HPCagA-VacA-. CONCLUSION: HPCagA+VacA+ promoted the invasiveness of AGS cells through up-regulation of ZEB1 transcription and claudin-2 and CDX-2 expression. CWNAE inhibited these effects of HPCagA+VacA+ on AGS cells by down-regulating ZEB1 transcription, and CDX-2 and claudin-2 expression.


Asunto(s)
Factor de Transcripción CDX2/metabolismo , Claudina-2/metabolismo , Curcuma/química , Helicobacter pylori/efectos de los fármacos , Extractos Vegetales/farmacología , Neoplasias Gástricas/microbiología , Línea Celular Tumoral , Helicobacter pylori/metabolismo , Humanos , Neoplasias Gástricas/tratamiento farmacológico
20.
Helicobacter ; 25(2): e12678, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-31880001

RESUMEN

BACKGROUND: In this study, one Helicobacter pylori isolate, from gastric biopsy of a dyspeptic patient that turned into mucoid-coccoid (MC) form upon consecutive subcultures, was identified. The culturability, antibiotic resistance, and lipid contents of MC were compared with those of non-mucoid (NM) spiral H pylori. MATERIALS AND METHODS: Mucoid-coccoid and NM H pylori were subcultured on Brucella blood agar (BBA) and incubated under aerobic and microaerobic atmospheres at 37°C. Cultures were examined for colony characteristics and bacterial morphology after 1-3 days. The isolates were identified by biochemical tests and detection of H pylori-16S rDNA. Antibiogram was performed with currently used antibiotics for H pylori eradication. Cellular lipid contents were extracted and analyzed by gas chromatography. RESULTS: Compared with pin-pointed and glistening colonies of NM H pylori that appeared under microaerobic conditions, MC H pylori grew well in consecutive subcultures under aerobic and microaerobic atmospheres and produced white patches of mucoid colonies. MC exhibited coccoid and NM spiral morphology. Both isolates were catalase, oxidase, and urease positive and contained 16S rDNA. Compared with NM that was susceptible to almost all the antibiotics, MC was resistant to all the antibiotics. Lipid analyses showed high frequency of unsaturated fatty acids and cholesterol in MC. CONCLUSIONS: Coccoid forms with high fatty acid and cholesterol contents that show resistance to antibiotics might resist against other stressful conditions such as gastric acidity and immune response. Moreover, mucoid property may enhance resistance of coccoids to stresses. With mucoid-coccoid lifestyle, H pylori may establish a chronic infection refractory to antimicrobial therapy.


Asunto(s)
Helicobacter pylori/citología , Helicobacter pylori/crecimiento & desarrollo , Helicobacter pylori/aislamiento & purificación , Colesterol/química , Farmacorresistencia Microbiana , Ácidos Grasos/química , Mucosa Gástrica/microbiología , Infecciones por Helicobacter/microbiología , Helicobacter pylori/metabolismo , Humanos , Pruebas de Sensibilidad Microbiana
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