scholarly journals The Hsp60 Protein of Helicobacter Pylori Exhibits Chaperone and ATPase Activities at Elevated Temperatures

BioChem ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 19-25
Author(s):  
Jose A. Mendoza ◽  
Julian L. Ignacio ◽  
Christopher M. Buckley
Keyword(s):  
Helicobacter Pylori ◽  
Heat Stress ◽  
Molecular Chaperone ◽  
Elevated Temperatures ◽  
Citrate Synthase ◽  
Gastric Epithelium ◽  
Acidic Conditions ◽  
H Pylori ◽  
Induced Aggregation ◽  
Hydrolysis Of

The heat-shock protein, Hsp60, is one of the most abundant proteins in Helicobacter pylori. Given its sequence homology to the Escherichia coli Hsp60 or GroEL, Hsp60 from H. pylori would be expected to function as a molecular chaperone in this organism. H. pylori is a type of bacteria that grows on the gastric epithelium, where the pH can fluctuate between neutral and 4.5, and the intracellular pH can be as low as 5.0. We previously showed that Hsp60 functions as a chaperone under acidic conditions. However, no reports have been made on the ability of Hsp60 to function as a molecular chaperone under other stressful conditions, such as heat stress or elevated temperatures. We report here that Hsp60 could suppress the heat-induced aggregation of the enzymes rhodanese, malate dehydrogenase, citrate synthase, and lactate dehydrogenase. Moreover, Hsp60 was found to have a potassium and magnesium-dependent ATPase activity that was stimulated at elevated temperatures. Although, Hsp60 was found to bind GTP, the hydrolysis of this nucleotide could not be observed. Our results show that Hsp60 from H. pylori can function as a molecular chaperone under conditions of heat stress.

scholarly journals Helicobacter pylori Outer Membrane Vesicles and Extracellular Vesicles from Helicobacter pylori-Infected Cells in Gastric Disease Development

2021 ◽  
Vol 22 (9) ◽  
pp. 4823
Author(s):  
María Fernanda González ◽  
Paula Díaz ◽  
Alejandra Sandoval-Bórquez ◽  
Daniela Herrera ◽  
Andrew F. G. Quest
Keyword(s):  
Gastric Cancer ◽  
Helicobacter Pylori ◽  
Outer Membrane ◽  
Extracellular Vesicles ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Host Cells ◽  
Gastric Epithelium ◽  
Infected Cells ◽  
H Pylori

Extracellular vesicles (EVs) are cell-derived vesicles important in intercellular communication that play an essential role in host-pathogen interactions, spreading pathogen-derived as well as host-derived molecules during infection. Pathogens can induce changes in the composition of EVs derived from the infected cells and use them to manipulate their microenvironment and, for instance, modulate innate and adaptive inflammatory immune responses, both in a stimulatory or suppressive manner. Gastric cancer is one of the leading causes of cancer-related deaths worldwide and infection with Helicobacter pylori (H. pylori) is considered the main risk factor for developing this disease, which is characterized by a strong inflammatory component. EVs released by host cells infected with H. pylori contribute significantly to inflammation, and in doing so promote the development of disease. Additionally, H. pylori liberates vesicles, called outer membrane vesicles (H. pylori-OMVs), which contribute to atrophia and cell transformation in the gastric epithelium. In this review, the participation of both EVs from cells infected with H. pylori and H. pylori-OMVs associated with the development of gastric cancer will be discussed. By deciphering which functions of these external vesicles during H. pylori infection benefit the host or the pathogen, novel treatment strategies may become available to prevent disease.

scholarly journals Nutrient Deficiency Promotes the Entry of Helicobacter pylori Cells into Candida Yeast Cells

Biology ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 426
Author(s):  
Kimberly Sánchez-Alonzo ◽  
Fabiola Silva-Mieres ◽  
Luciano Arellano-Arriagada ◽  
Cristian Parra-Sepúlveda ◽  
Humberto Bernasconi ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Nutrient Deficiency ◽  
Gastric Epithelium ◽  
Yeast Cells ◽  
Nutrient Concentrations ◽  
Fetal Bovine ◽  
H Pylori ◽  
Pcr Techniques ◽  
Strain Dependent

Helicobacter pylori, a Gram-negative bacterium, has as a natural niche the human gastric epithelium. This pathogen has been reported to enter into Candida yeast cells; however, factors triggering this endosymbiotic relationship remain unknown. The aim of this work was to evaluate in vitro if variations in nutrient concentration in the cultured medium trigger the internalization of H. pylori within Candida cells. We used H. pylori–Candida co-cultures in Brucella broth supplemented with 1%, 5% or 20% fetal bovine serum or in saline solution. Intra-yeast bacteria-like bodies (BLBs) were observed using optical microscopy, while intra-yeast BLBs were identified as H. pylori using FISH and PCR techniques. Intra-yeast H. pylori (BLBs) viability was confirmed using the LIVE/DEAD BacLight Bacterial Viability kit. Intra-yeast H. pylori was present in all combinations of bacteria–yeast strains co-cultured. However, the percentages of yeast cells harboring bacteria (Y-BLBs) varied according to nutrient concentrations and also were strain-dependent. In conclusion, reduced nutrients stresses H. pylori, promoting its entry into Candida cells. The starvation of both H. pylori and Candida strains reduced the percentages of Y-BLBs, suggesting that starving yeast cells may be less capable of harboring stressed H. pylori cells. Moreover, the endosymbiotic relationship between H. pylori and Candida is dependent on the strains co-cultured.

scholarly journals Zerumbone Inhibits Helicobacter pylori Urease Activity

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2663
Author(s):  
Hyun Jun Woo ◽  
Ji Yeong Yang ◽  
Pyeongjae Lee ◽  
Jong-Bae Kim ◽  
Sa-Hyun Kim
Keyword(s):  
Helicobacter Pylori ◽  
Carbon Atom ◽  
Natural Compound ◽  
Urease Activity ◽  
Negative Charge ◽  
Positive Charge ◽  
Gastric Epithelium ◽  
Functional Inhibition ◽  
Electrical Gradient ◽  
H Pylori

Helicobacter pylori (H. pylori) produces urease in order to improve its settlement and growth in the human gastric epithelium. Urease inhibitors likely represent potentially powerful therapeutics for treating H. pylori; however, their instability and toxicity have proven problematic in human clinical trials. In this study, we investigate the ability of a natural compound extracted from Zingiber zerumbet Smith, zerumbone, to inhibit the urease activity of H. pylori by formation of urease dimers, trimers, or tetramers. As an oxygen atom possesses stronger electronegativity than the first carbon atom bonded to it, in the zerumbone structure, the neighboring second carbon atom shows a relatively negative charge (δ−) and the next carbon atom shows a positive charge (δ+), sequentially. Due to this electrical gradient, it is possible that H. pylori urease with its negative charges (such as thiol radicals) might bind to the β-position carbon of zerumbone. Our results show that zerumbone dimerized, trimerized, or tetramerized with both H. pylori urease A and urease B molecules, and that this formation of complex inhibited H. pylori urease activity. Although zerumbone did not affect either gene transcription or the protein expression of urease A and urease B, our study demonstrated that zerumbone could effectively dimerize with both urease molecules and caused significant functional inhibition of urease activity. In short, our findings suggest that zerumbone may be an effective H. pylori urease inhibitor that may be suitable for therapeutic use in humans.

scholarly journals Helicobacter Pylori Induce Gastric Upset

2021 ◽  
pp. 1-1
Author(s):  
Hazim Abdul Rahman Alhit
Keyword(s):  
Gastric Cancer ◽  
Helicobacter Pylori ◽  
Serum Antibody ◽  
Endoscopic Biopsy ◽  
Helicobacter Pylori Infection ◽  
Gastric Epithelium ◽  
Gastric Diseases ◽  
Heterogeneous Distribution ◽  
Cytotoxin Associated Gene A ◽  
H Pylori

Editorial: Helicobacter pylori is a micro-aerophilic, helical-form gramnegative aggressive bacteria. Accordingly, the idiom “Helico” intimates its helical appearance, “bacter” symbolizes bacteria, while “pylori” denotes stomach due to the first and common site of this bacteria living. Further, Marshall B. and Warren R. observed and described it in 1982. Then, the followed investigators studied this bacterium in detail with its consequences and complexities [1]. Gastric upset (Indigestion), dyspepsia: means impaired gastric digestion. Accordingly, the patient complains of upper abdominal pain, heartburn, belching, nausea, even feeling earlier gastric fullness than expected while eating. Furthermore, there are many causes of indigestion like gastroesophageal reflux disease, ulcer disease, gastritis, and even gastric cancer. Hence, unexplained recent onset dyspepsia in older people may need additional examinations. Moreover, one of the common causes is Helicobacter pylori infection, which needs laboratory and endoscopic examination [2]. Argument Many theories investigated the etiology and pathogenesis of Helicobacter pylori infection, concerning chronic or acute gastritis. Hence, gastric upset is the main presentation of both types of gastritis. Evidences The genotype is valuable in determining the dominant Helicobacter pylori strains as the isolates were different genetically plus heterogeneous distribution. Accordingly, the vac and cag markers operate a significant function in defining clinical consequences. These virulence agents are present in a subset of Helicobacter pylori strains isolates like cagA, iceA, vacA, and ureC. Moreover, the cagA causes cytotoxins induction by the gastric epithelial cell as Interleukin 8 [3]. The molecular intercommunication researches exhibit that the act of acarus calamus in hindering biofilm formation in Helicobacter pylori is due to the inhibitory impact of phytobio-active component, β-sitosterol, on the quorum sensing molecules-ToxB, PhnB, DnaA, plus Sip. Consequently, this opinion may suggest the molecular mechanism of Helicobacter pylori in producing the acidrelated complaints and gives a clue to a new therapy [4]. Helicobacter pylori infection causes lncRNA risk impression linked to H. pylori in gastric cancer patients and can prognosticate the prediction of these patients [5]. There was a close relationship between raised serum IgE levels in Helicobacter pylori infected patients [6]. Counterargument The laboratory investigations of Helicobacter pylori infection depend on several factors like the fluctuations of serum antibody titers in a time series, the antigene detection in stool tests, the false-positive results of lab tests, or the manner of endoscopic biopsy collection. Furthermore, other factors like the variations in Cytotoxin-Associated Gene A (CagA) in East Asian patients. Moreover, the gastric nodularity or atrophy, the patient’s age, the severity of the gastric mucosal infection are causes of variations in Helicobacter pylori detection at the time of the investigation [7]. Refutation The significant markers of H. pylori, the presence of the vacuolating cytotoxin (vacA), the cytotoxin-associated gene A (cagA), which induced by the direct communication with gastric epithelium factor antigen (iceA gene), and the presence of urease C gene (ureC). Consequently, all these factors play the principal factors in deciding the gastric consequences of Helicobacter infections. Conclusion Helicobacter pylori induce gastric upset by several mechanisms to form numerous Gastric diseases.

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

2020 ◽  
Vol 318 (5) ◽  
pp. G931-G945 ◽  
Author(s):  
Elizabeth A. Marcus ◽  
Elmira Tokhtaeva ◽  
Jossue L. Jimenez ◽  
Yi Wen ◽  
Bita V. Naini ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Helicobacter Pylori ◽  
Cultured Cells ◽  
Proteasomal Degradation ◽  
Helicobacter Pylori Infection ◽  
Gastric Epithelium ◽  
Native Enzyme ◽  
Gastric Injury ◽  
Atpase Subunits ◽  
H Pylori

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.

scholarly journals Helicobacter pylori is killed by nitrite under acidic conditions

Gut ◽  
1998 ◽  
Vol 42 (3) ◽  
pp. 334-337 ◽  
Author(s):  
R S Dykhuizen ◽  
A Fraser ◽  
H McKenzie ◽  
M Golden ◽  
C Leifert ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Anaerobic Bacteria ◽  
Antimicrobial Effect ◽  
Human Stomach ◽  
Bacterial Survival ◽  
Novel Host ◽  
Potassium Nitrite ◽  
Acidic Conditions ◽  
H Pylori ◽  
Facultative Anaerobic Bacteria

Background—Due to the expression of urease,Helicobacter pylori is able to establish itself in the human stomach under acidic conditions. A novel host defence mechanism was recently proposed, suggesting that the formation of salivary nitrite in symbiosis with facultative anaerobic bacteria in the oropharynx, is aimed at enhancing the antimicrobial activity of gastric juice.Aims—To investigate whether the addition of nitrite in physiological concentrations influences the resistance ofH pylori to acid.Methods—H pylori cultured from fresh gastric biopsy specimens was exposed for 30 minutes to normal saline and to HCl/KCl buffer (0.2M) at pH 2 with urea (5 mM) added. The influence of potassium nitrite (50–1000 μmol/l) on bacterial survival was determined.Results—Addition of nitrite (1 mM) to acidic solutions (pH 2) resulted in complete kill of H pyloriwithin 30 minutes exposure time whereas acid alone allowed the organism to survive (p<0.001). The antimicrobial effect of nitrite at pH 2 against H pylori was dose dependent and complete kill of organisms occurred at concentrations ⩾500 μmol/l.Conclusion—Acidified nitrite has antibacterial activity against H pylori. This should prompt further research into the effect of salivary nitrite on the survival of H pylori in the human stomach.

scholarly journals Comparison of CXC Chemokines ENA-78 and Interleukin-8 Expression in Helicobacter pylori-Associated Gastritis

2001 ◽  
Vol 69 (1) ◽  
pp. 81-88 ◽  
Author(s):  
Gabriele Rieder ◽  
Wolfgang Einsiedl ◽  
Rudolf A. Hatz ◽  
Manfred Stolte ◽  
Georg A. Enders ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Protein Expression ◽  
Outer Membrane Proteins ◽  
Water Soluble ◽  
Interleukin 8 ◽  
Gastric Epithelium ◽  
Mrna Levels ◽  
Rt Pcr ◽  
H Pylori

ABSTRACT Colonization of the gastric mucosa with Helicobacter pylori is associated with a dense infiltration of granulocytes into the lamina propria in the active phase of gastritis. In this study, we investigated the involvement of epithelial cell-derived neutrophil-activating protein 78 (ENA-78) in development of H. pylori-associated gastritis. Antral biopsies from 27 patients with H. pylori-associated gastritis and 25 from H. pylori-negative individuals were first analyzed for ENA-78 and interleukin-8 (IL-8) mRNA by semiquantitative reverse transcription (RT)-PCR. In H. pylori-positive patients, significantly elevated levels were found for both chemokines (P < 0.05). Only IL-8 mRNA levels differed significantly (P< 0.05) in H. pylori-infected individuals who had serum antibodies for cytotoxin-associated protein CagA versus H. pylori-infected CagA-negative persons. Quantification of ENA-78 transcript levels by competitive RT-PCR yielded a significant 45-fold upregulation for ENA-78 transcripts in biopsies of H. pylori-positive versus H. pylori-negative patients (P < 0.05). In contrast to earlier findings with IL-8, the degree of ENA-78 mRNA upregulation was independent of the grade of activity of gastritis. Immunofluorescence studies on tissues of antral biopsies localized ENA-78 protein expression mainly to the gastric epithelium of H. pylori-positive patients, while control tissues were negative. Upregulation of ENA-78 and IL-8 mRNA and protein expression was also observed in an in vitro system using a gastric adenocarcinoma cell line. Only viable H. pyloriyielded a strong ENA-78 and IL-8 induction, while H. pyloriouter membrane proteins or water-soluble proteins had no significant effect. These data provide evidence for the importance of both IL-8 and ENA-78 in the development and perpetuation of H. pylori-associated gastritis.

scholarly journals Virulent Strains of Helicobacter pylori Demonstrate Delayed Phagocytosis and Stimulate Homotypic Phagosome Fusion in Macrophages

2000 ◽  
Vol 191 (1) ◽  
pp. 115-128 ◽  
Author(s):  
Lee-Ann H. Allen ◽  
Larry S. Schlesinger ◽  
Byoung Kang
Keyword(s):  
Helicobacter Pylori ◽  
Mononuclear Phagocytes ◽  
Gastric Epithelium ◽  
Type I ◽  
Causative Role ◽  
Type Ii ◽  
Duodenal Ulcers ◽  
H Pylori ◽  
Phagosome Fusion ◽  
Bacterial Protein Synthesis

Helicobacter pylori colonizes the gastric epithelium of ∼50% of the world's population and plays a causative role in the development of gastric and duodenal ulcers. H. pylori is phagocytosed by mononuclear phagocytes, but the internalized bacteria are not killed and the reasons for this host defense defect are unclear. We now show using immunofluorescence and electron microscopy that H. pylori employs an unusual mechanism to avoid phagocytic killing: delayed entry followed by homotypic phagosome fusion. Unopsonized type I H. pylori bound readily to macrophages and were internalized into actin-rich phagosomes after a lag of ∼4 min. Although early (10 min) phagosomes contained single bacilli, H. pylori phagosomes coalesced over the next ∼2 h. The resulting “megasomes” contained multiple viable organisms and were stable for 24 h. Phagosome–phagosome fusion required bacterial protein synthesis and intact host microtubules, and both chloramphenicol and nocodazole increased killing of intracellular H. pylori. Type II strains of H. pylori are less virulent and lack the cag pathogenicity island. In contrast to type I strains, type II H. pylori were rapidly ingested and killed by macrophages and did not stimulate megasome formation. Collectively, our data suggest that megasome formation is an important feature of H. pylori pathogenesis.

Expression of Cytokeratins 7 and 20 in Helicobacter pylori-associated Chronic Gastritis in Children

2004 ◽  
Vol 7 (2) ◽  
pp. 180-186 ◽  
Author(s):  
M. Cohen ◽  
E. Cueto Rúa ◽  
N. Balcarce ◽  
R. Drut
Keyword(s):  
Helicobacter Pylori ◽  
Chronic Gastritis ◽  
Structural Changes ◽  
Periodic Acid ◽  
Gastric Epithelium ◽  
Surface Epithelium ◽  
Ki 67 ◽  
Periodic Acid Schiff ◽  
Group A ◽  
H Pylori

Helicobacter pylori gastric infection induces structural changes in the gastric epithelium. Among them, variations in the expression of cytokeratins have been reported in adult patients. In the present study, we describe the expression of CK7 and CK20 in gastric samples taken from the antrum in three groups of pediatric patients: (A) Helicobacter pylori-associated chronic gastritis (mean age: 11.4 years); (B) previous H. pylori chronic gastritis patients (mean age: 9.4 years); and (C) controls (mean age: 8.8 years). In all, the presence of sulfomucins was assessed with Alcian blue-periodic acid-Schiff pH 1.0. Immunoreactivity was graded as absent (0), weak (1 +), moderate (2+), or intense (3+), in accordance with the intensity of the staining, and its distribution as focal or diffuse. CK7 reactivity was 2 + either focal or diffuse in all group A biopsies. The reactivity was more evident in the cells at the neck of the glands, in the areas with more inflammatory infiltrates, decorating long vertical segments of epithelium. In groups B and C, CK7 reactivity was also focal and 1 + at the cells of the necks of the glands. However, group B presented longer vertical segments of positive cells as compared to group C, and shorter than those of group A. The deeper glandular structures were focally 1 + in both groups. CK20 expression was comparable in all three groups, depicting a 2+ diffuse reactivity at the surface epithelium and interposed pits with absence or focal reactivity at the neck and coiled gland areas. Ki-67 immunostaining paralleled that of the CK7. Staining for sulfated mucosubstances was positive in two of five cases of groups A and B, and in none of the cases of group C. We conclude that: (1) the long segments of CK7-positive glandular necks in H. pylori cases most probably indicate intense regenerative activity during active inflammation; (2) eradication of H. pylori does not warrant ad integrum restitution since long segments of Ki-67+, CK7+ cells at the germinative compartment of the glands (as well as cells with sulfomucins) were still recognizable in ex- H. pylori patients; (3) finally, differing from what happens in adults, children somehow manage to maintain fully differentiated CK20+ superficial epithelium while the H. pylori is in action.

scholarly journals Analysis of heat-induced protein aggregation in human mitochondria

2018 ◽  
Author(s):  
Anne Wilkening ◽  
Cornelia Rüb ◽  
Marc Sylvester ◽  
Wolfgang Voos
Keyword(s):  
Heat Stress ◽  
Mammalian Cells ◽  
Elevated Temperatures ◽  
Protein Biosynthesis ◽  
High Sensitivity ◽  
Small Subset ◽  
Loss Of Function ◽  
Mitochondrial Translation ◽  
The Impact ◽  
Induced Aggregation

AbstractAs proteins in mammalian cells exhibit optimal stability at natural temperatures, small temperature variations may cause unfolding and subsequent non-specific aggregation. As this process leads to a loss of function of the affected polypeptides as well as to further cytotoxic stress, aggregate formation has been recognized as a major pathogenic factor in human diseases. In this study we determined the impact of physiological heat stress on mammalian mitochondria on a proteomic level. The overall solubility of endogenous mitochondrial proteins was only marginally affected by a treatment at elevated temperatures. However, we identified a small subset of polypeptides that exhibited an exceptionally high sensitivity to heat stress. The mitochondrial translation elongation factor Tu (Tufm), a protein essential for organellar protein biosynthesis, was highly aggregation-prone and lost its solubility already under mild heat stress conditions. In parallel, mitochondrial translation as well as the import of cytosolic proteins was defective in heat stressed mitochondria. Both types of nascent polypeptides, derived from translation as well as from import exhibited a strong heat-induced aggregation tendency. We propose a model that a quick and specific inactivation of elongation factors may prevent an accumulation of misfolded nascent polypeptides and thereby attenuate proteotoxicity under stress.

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