Structural basis for the peptidoglycan recognition by Helicobacter pylori Csd4

Helicobacter pylori infection causes a variety of gastrointestinal diseases including peptic ulcers and gastric cancer. The colonization of this bacterium in the gastric mucosa is required for the survival in the stomach. Its colonization of the gastric mucosa of human stomach depends on its motility, which is facilitated by the helical cell shape. In H. pylori, crosslinking relaxation or trimming of peptidoglycan muropeptide affects the helical shape. Among several cell shape-determining peptidoglycan hydrolases identified in H. pylori, Csd4 is a Zn2+-dependent D,L-carboxypeptidase that cleaves the bond between the γ-D-Glu and mDAP bond of the uncrosslinked tripeptide of peptidoglycan (L-Ala-γ-D-Glu-mDAP) to produce L-Ala-γ-D-Glu dipeptide and mDAP, promoting the helical cell shape. Inhibition of D,L-carboxypeptidase activity of Csd4 may represent a novel therapeutic approach. We report here the crystal structures of H. pylori Csd4 in three different states: the ligand-free form, the substrate-bound form, and the product-bound form. H. pylori Csd4 consists of three domains: an N-terminal D,L-carboxypeptidase domain, a novel β-barrel domain, and a C-terminal immunoglobulin-like domain. Our ligand-bound structures provide structural basis of peptidoglycan recognition by D,L-carboxypeptidase. H. pylori Csd4 recognizes primarily the terminal mDAP of the tripeptide substrate and undergoes a significant structural change upon binding either mDAP or mDAP-containing tripeptide.

Download Full-text

Structural basis for the recognition of muramyltripeptide byHelicobacter pyloriCsd4, aD,L-carboxypeptidase controlling the helical cell shape

Acta Crystallographica Section D Biological Crystallography ◽

10.1107/s1399004714018732 ◽

2014 ◽

Vol 70 (11) ◽

pp. 2800-2812 ◽

Cited By ~ 14

Author(s):

Hyoun Sook Kim ◽

Jieun Kim ◽

Ha Na Im ◽

Doo Ri An ◽

Mijoon Lee ◽

...

Keyword(s):

Crystal Structure ◽

Cell Shape ◽

Gastrointestinal Diseases ◽

Human Stomach ◽

Structural Basis ◽

Cross Linking ◽

Peptic Ulcers ◽

Significant Structural Change ◽

Peptidoglycan Hydrolases ◽

H Pylori

Helicobacter pyloriinfection causes a variety of gastrointestinal diseases, including peptic ulcers and gastric cancer. Its colonization of the gastric mucosa of the human stomach is a prerequisite for survival in the stomach. Colonization depends on its motility, which is facilitated by the helical shape of the bacterium. InH. pylori, cross-linking relaxation or trimming of peptidoglycan muropeptides affects the helical cell shape. Csd4 has been identified as one of the cell shape-determining peptidoglycan hydrolases inH. pylori. It is a Zn2+-dependent D,L-carboxypeptidase that cleaves the bond between the γ-D-Glu and themDAP of the non-cross-linked muramyltripeptide (muramyl-L-Ala-γ-D-Glu-mDAP) of the peptidoglycan to produce the muramyldipeptide (muramyl-L-Ala-γ-D-Glu) andmDAP. Here, the crystal structure ofH. pyloriCsd4 (HP1075 in strain 26695) is reported in three different states: the ligand-unbound form, the substrate-bound form and the product-bound form.H. pyloriCsd4 consists of three domains: an N-terminal D,L-carboxypeptidase domain with a typical carboxypeptidase fold, a central β-barrel domain with a novel fold and a C-terminal immunoglobulin-like domain. The D,L-carboxypeptidase domain recognizes the substrate by interacting primarily with the terminalmDAP moiety of the muramyltripeptide. It undergoes a significant structural change upon binding eithermDAP or themDAP-containing muramyltripeptide. It it also shown that Csd5, another cell-shape determinant inH. pylori, is capable of interacting not only withH. pyloriCsd4 but also with the dipeptide product of the reaction catalyzed by Csd4.

Download Full-text

Structural basis of Lewisb antigen binding by the Helicobacter pylori adhesin BabA

Science Advances ◽

10.1126/sciadv.1500315 ◽

2015 ◽

Vol 1 (7) ◽

pp. e1500315 ◽

Cited By ~ 36

Author(s):

Naim Hage ◽

Tina Howard ◽

Chris Phillips ◽

Claire Brassington ◽

Ross Overman ◽

...

Keyword(s):

Helicobacter Pylori ◽

Gastric Mucosa ◽

Structural Model ◽

Tertiary Structure ◽

Structural Information ◽

Structural Basis ◽

Side Chain ◽

Negative Bacterium ◽

Network Of Hydrogen Bonds ◽

H Pylori

Helicobacter pylori is a leading cause of peptic ulceration and gastric cancer worldwide. To achieve colonization of the stomach, this Gram-negative bacterium adheres to Lewisb (Leb) antigens in the gastric mucosa using its outer membrane protein BabA. Structural information for BabA has been elusive, and thus, its molecular mechanism for recognizing Leb antigens remains unknown. We present the crystal structure of the extracellular domain of BabA, from H. pylori strain J99, in the absence and presence of Leb at 2.0- and 2.1-Å resolutions, respectively. BabA is a predominantly α-helical molecule with a markedly kinked tertiary structure containing a single, shallow Leb binding site at its tip within a β-strand motif. No conformational change occurs in BabA upon binding of Leb, which is characterized by low affinity under acidic [KD (dissociation constant) of ~227 μM] and neutral (KD of ~252 μM) conditions. Binding is mediated by a network of hydrogen bonds between Leb Fuc1, GlcNAc3, Fuc4, and Gal5 residues and a total of eight BabA amino acids (C189, G191, N194, N206, D233, S234, S244, and T246) through both carbonyl backbone and side-chain interactions. The structural model was validated through the generation of two BabA variants containing N206A and combined D233A/S244A substitutions, which result in a reduction and complete loss of binding affinity to Leb, respectively. Knowledge of the molecular basis of Leb recognition by BabA provides a platform for the development of therapeutics targeted at inhibiting H. pylori adherence to the gastric mucosa.

Download Full-text

Pathogenesis of Helicobacter pylori Infection

Clinical Microbiology Reviews ◽

10.1128/cmr.00054-05 ◽

2006 ◽

Vol 19 (3) ◽

pp. 449-490 ◽

Cited By ~ 1102

Author(s):

Johannes G. Kusters ◽

Arnoud H. M. van Vliet ◽

Ernst J. Kuipers

Keyword(s):

Helicobacter Pylori ◽

Gastric Mucosa ◽

Clinical Symptoms ◽

Gastrointestinal Diseases ◽

Immune Gene ◽

Human Pathogens ◽

Vacuolating Cytotoxin ◽

Chronic Active Gastritis ◽

Key Factor ◽

H Pylori

SUMMARY Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori.

Download Full-text

Upregulation of CCL20 and Recruitment of CCR6+ Gastric Infiltrating Lymphocytes in Helicobacter pylori Gastritis

Infection and Immunity ◽

10.1128/iai.01660-06 ◽

2007 ◽

Vol 75 (9) ◽

pp. 4357-4363 ◽

Cited By ~ 39

Author(s):

Yi-Ying Wu ◽

Hwei-Fang Tsai ◽

We-Cheng Lin ◽

Ping-I Hsu ◽

Chia-Tung Shun ◽

...

Keyword(s):

T Cells ◽

Helicobacter Pylori ◽

Gastric Mucosa ◽

Inflammatory Response ◽

Chemokine Receptor ◽

Ex Vivo ◽

Peptic Ulcers ◽

Lymphocyte Trafficking ◽

Necrosis Factor Alpha ◽

H Pylori

ABSTRACT Helicobacter pylori infection is associated with an inflammatory response in the gastric mucosa, leading to chronic gastritis, peptic ulcers, and gastric cancer. There is increased T-cell infiltration at the site of infection with H. pylori. CCR6, a specific β-chemokine receptor for CCL20 (MIP-3α/LARC/exodus), has recently been reported to mediate lymphocyte homeostasis and immune responses in mucosal tissue, and it may play a role in chemokine-mediated lymphocyte trafficking during gastric inflammation. In this study, we investigated the role of CCR6 and its ligand, CCL20, in inducing an inflammatory response in the gastric mucosa during H. pylori infection. Gastric infiltrating T lymphocytes were isolated from endoscopic biopsy specimens of H. pylori gastritis patients and analyzed for the expression of the CCR6 chemokine receptor. Our results demonstrated that there was significantly increased CCR6 expression in CD3+ T cells infiltrating the gastric mucosa, and the CCR6 ligand, the CCL20 chemokine, was selectively expressed in inflamed gastric tissues. The production of CCL20 was upregulated in response to H. pylori in gastric epithelial cells when there was stimulation by the proinflammatory cytokines interleukin-1β and tumor necrosis factor alpha. Furthermore, recombinant CCL20 induced lymphocyte chemotaxis migration in fresh gastric T cells ex vivo, indicating that the gastric T cells could migrate toward inflammatory sites via CCR6/CCL20 interaction. Our results suggest that the interaction between CCL20 and CCR6 may play a role in chemokine-mediated lymphocyte trafficking during gastric inflammation in Helicobacter infection.

Download Full-text

Cost-effectiveness Analysis Comparing Vonoprazanbased Triple Therapy with Proton Pump Inhibitorbased Therapy in the Treatment of Helicobacter pylori Infection in Thailand

Siriraj Medical Journal ◽

10.33192/smj.2021.107 ◽

2021 ◽

Vol 73 (12) ◽

pp. 823-831

Author(s):

Jadesada Lertsirimunkong ◽

Wiwat Thavornwattanayong ◽

Yosita Napuk ◽

Watcharapong Ajcharoen ◽

Vipavee Chaisitsanguan ◽

...

Keyword(s):

Helicobacter Pylori ◽

Cost Effectiveness ◽

Triple Therapy ◽

Gastrointestinal Diseases ◽

Dominant Strategy ◽

Peptic Ulcers ◽

Life Years ◽

First Choice ◽

H Pylori ◽

The Cost

Objective: Helicobacter pylori (H. pylori) infection is one of the leading causes of gastrointestinal diseases such as dyspepsia, peptic ulcers. Thailand has a 45.9% prevalence of the infection and an increasing rate of resistance to clarithromycin, leading to standard treatments being less successful. Vonoprazan represents a novel drug offering a new treatment regimen. Although vonoprazan has been available in Thailand since 2019, its cost-effectiveness has not been studied previously.Materials and Methods: This study analysed the cost-effectiveness of vonoprazan-based triple therapy compared with PPI-based therapy, in treating clarithromycin resistant H. pylori, by using the markov model from a societal perspective.Results: The total cost of vonoprazan-based triple therapy, levofloxacin-PPI based triple therapy and concomitant-PPI therapy were 784,932.08 baht, 783,863.65 baht and 783,874.55 baht respectively. The quality-adjusted life years (QALYs) of vonoprazan-based triple therapy, levofloxacin-PPI based triple therapy and concomitant-PPI therapy were 25.1118 years, 25.1147 years and 25.1054 years respectively. The cost-effectiveness ratio (CER) of vonoprazanbased triple therapy, levofloxacin-PPI based triple therapy and concomitant-PPI therapy were 31,257.50 baht/ QALYs, 31,211.35 baht/QALYs and 31,223.34 baht per QALYs respectively.Conclusion: Therefore, levofloxacin-PPI based triple therapy was found to be the most cost-effective regimen and the dominant strategy compared with concomitant-PPI or vonoprazan-based triple therapy. It provided higher QALYs and lower treatment costs. Levofloxacin-PPI based triple therapy should be the first choice of an alternative strategy in treating clarithromycin-resistant H. pylori. The results of this study can be used by policymakers to help inform their decisions.

Download Full-text

Effects of Infections of Helicobacter Pylori With Different Virulent Factors on Severity of Gastrointestinal Diseases

10.21203/rs.3.rs-148511/v1 ◽

2021 ◽

Author(s):

Yan Zhang ◽

Xiang-ming Fang ◽

Kui Tian

Keyword(s):

Helicobacter Pylori ◽

Bacterial Infections ◽

Gastrointestinal Diseases ◽

Ulcer Bleeding ◽

Type I ◽

Peptic Ulcers ◽

Type Ii ◽

Type Iii ◽

Significant Difference ◽

H Pylori

Abstract Background: Helicobacter Pylori (H. pylori) infection, one of the most common chronic bacterial infections, has been considered as a major cause of diseases such as lymphoma, gastritis, peptic ulcers, and stomach cancer. Here, we aimed to determine whether H. pylori strains with different virulence contribute to the gastrointestinal diseases differentially in clinical settings, which may provide future direction for eradication of H. pylori infection. Methods: We recruited 501 patients with gastrointestinal disorders for analysis of antibody types of H. pylori infection. Correlation analysis was done to determine the association of different virulence of H. pylori with patients’ baseline parameters and personal disease history. Next, subjects with each type of anti- H. pylori infection antibody were subjected to esophagogastro duodenoscopy（EGD) and colonoscopy examinations. The pathological diagnosis was also conducted in endoscopic samples. Chi-squared test was employed to compare the differences in endoscopic assessments and pathological findings among three types of H. pylori infection determined by the presence of antibodies to virulent factors. Results: There were 296 cases with Type I H. pylori infection, 120 cases with Type II H. pylori infection, and 85 cases without H. pylori infection (negative, Type III). No correlation was found between different virulence of H. pylori and participants’ baseline data (P > 0.05). EGD results showed that the incidences of peptic ulcer, bleeding and malignant lesions in Type I group were significantly higher than that in Type II and Type III (P＜0.05). Despite of increased trends of incidences of precancerous alterations and the malignance in Type I group compared with type II and III groups, there was no significant difference (P > 0.05). In addition, coloscopic features were similar among three groups. On the other hand, infections of H. pylori with cytotoxin-associated gene A (CagA) and/or vacuolating cytotoxin A (VacA) virulent factors resulted in more severe histopathological diseases than that with only Ure A/B factor and without infection (P < 0.05). Conclusions: Infections of H. pylori strains with CagA/VacA are likely to cause development of severe gastrointestinal diseases. These results are helpful to treat for H. pylori infection clinically.

Download Full-text

High prevalence of cytotoxin positive Helicobacter pylori in patients unrelated to the presence of peptic ulcers in Japan

Gut ◽

10.1136/gut.41.4.463 ◽

1997 ◽

Vol 41 (4) ◽

pp. 463-468 ◽

Cited By ~ 26

Author(s):

K Ogura ◽

F Kanai ◽

S Maeda ◽

H Yoshida ◽

M Ogura ◽

...

Keyword(s):

Helicobacter Pylori ◽

Western Blot ◽

Gastrointestinal Diseases ◽

Normal Mucosa ◽

Peptic Ulcers ◽

Western Blot Assay ◽

Vacuolating Cytotoxin ◽

Western Blot Method ◽

High Prevalence ◽

H Pylori

Background—It has been reported that infection with vacuolating cytotoxin positive Helicobacter pyloristrains is associated with gastroduodenal disease in Western countries.Aims—To evaluate the prevalence of cytotoxin producing strains among patients with H pyloriinfection in relation to gastrointestinal diseases in Japan.Patients—Ninety seven patients undergoing endoscopy.Methods—A Western blot assay was conducted to detect serum antibodies against the cytotoxin using recombinant cytotoxin (VacA protein) as an antigen. To obtain a purified recombinant cytotoxin, the vacA gene (2233 nucleotides) was cloned into an expression vector to produce the protein (744 amino acids), which was expressed in Escherichia coli.Results—Serum IgG antibodies to the cytotoxin were present in 85%, 95%, 95%, and 100% of infected patients with gastric ulcer (n=26), duodenal ulcer (n=21), chronic gastritis (n=19), and endoscopically normal mucosa (n=14), respectively.Conclusion—The western blot method using recombinant VacA protein is simple and useful for detecting antibody to vacuolating cytotoxin. This method showed antibodies against cytotoxin were highly prevalent, even in subjects with endoscopically normal mucosa in Japan, indicating that the cytotoxin may not be an independent cause of gastrointestinal diseases induced by H pylori infection.

Download Full-text

Adhesion of Helicobacter Species to the Human Gastric Mucosa: A Deep Look Into Glycans Role

Frontiers in Molecular Biosciences ◽

10.3389/fmolb.2021.656439 ◽

2021 ◽

Vol 8 ◽

Author(s):

Rita Matos ◽

Irina Amorim ◽

Ana Magalhães ◽

Freddy Haesebrouck ◽

Fátima Gärtner ◽

...

Keyword(s):

Helicobacter Pylori ◽

Gastric Mucosa ◽

Human Stomach ◽

Gastric Disease ◽

Human Gastric Mucosa ◽

Peptic Ulcers ◽

Epithelial Surface ◽

Natural Hosts ◽

Glycan Receptors ◽

H Pylori

Helicobacter species infections may be associated with the development of gastric disorders, such as gastritis, peptic ulcers, intestinal metaplasia, dysplasia and gastric carcinoma. Binding of these bacteria to the gastric mucosa occurs through the recognition of specific glycan receptors expressed by the host epithelial cells. This review addresses the state of the art knowledge on these host glycan structures and the bacterial adhesins involved in Helicobacter spp. adhesion to gastric mucosa colonization. Glycans are expressed on every cell surface and they are crucial for several biological processes, including protein folding, cell signaling and recognition, and host-pathogen interactions. Helicobacter pylori is the most predominant gastric Helicobacter species in humans. The adhesion of this bacterium to glycan epitopes present on the gastric epithelial surface is a crucial step for a successful colonization. Major adhesins essential for colonization and infection are the blood-group antigen-binding adhesin (BabA) which mediates the interaction with fucosylated H-type 1 and Lewis B glycans, and the sialic acid-binding adhesin (SabA) which recognizes the sialyl-Lewis A and X glycan antigens. Since not every H. pylori strain expresses functional BabA or SabA adhesins, other bacterial proteins are most probably also involved in this adhesion process, including LabA (LacdiNAc-binding adhesin), which binds to the LacdiNAc motif on MUC5AC mucin. Besides H. pylori, several other gastric non-Helicobacter pylori Helicobacters (NHPH), mainly associated with pigs (H. suis) and pets (H. felis, H. bizzozeronii, H. salomonis, and H. heilmannii), may also colonize the human stomach and cause gastric disease, including gastritis, peptic ulcers and mucosa-associated lymphoid tissue (MALT) lymphoma. These NHPH lack homologous to the major known adhesins involved in colonization of the human stomach. In humans, NHPH infection rate is much lower than in the natural hosts. Differences in the glycosylation profile between gastric human and animal mucins acting as glycan receptors for NHPH-associated adhesins, may be involved. The identification and characterization of the key molecules involved in the adhesion of gastric Helicobacter species to the gastric mucosa is important to understand the colonization and infection strategies displayed by different members of this genus.

Download Full-text

Increased Production of Matrix Metalloproteinases in Helicobacter pylori Infection that Stimulates Gastric Cancer Stem Cells

International Journal of Veterinary Science ◽

10.37422/ijvs/20.043 ◽

2020 ◽

Keyword(s):

Gastric Cancer ◽

Stem Cells ◽

Helicobacter Pylori ◽

Cancer Stem Cells ◽

Histopathological Examination ◽

Physiological Saline ◽

Rrna Gene ◽

Peptic Ulcers ◽

Gastric Cancer Stem Cells ◽

H Pylori

Background and aim: Helicobacter pylori (H. pylori) is an incriminated pathogen causing diseases in both animals and humans and considered a zoonotic pathogen. H. pylori infection is considered a cause of gastric cancer, which rests a significant health care challenge. This study analyzes the expression pattern of matrix metalloprotein 2 (MMP-2) in patients with Helicobacter pylori-associated gastritis and the effect of H. pylori on gastric cancer stem cells, as well as study the role of helicon bacteriosis in dog in transmission of H. pylori infection to human. Materials and methods: Fifty-five of each sample (gastric biopsy, blood and stool) were collected from patients suffering from dyspepsia, chronic vomiting and perforated peptic ulcers and also from apparent healthy dogs. The investigation detected H. pylori by serological and histopathological examination. Biopsies were stored in physiological saline for identification of H. pylori by conventional time PCR. MMP-2 and Gastric cancer stem cells were then identified by immunohistochemistry. Results: Serological identification for H. pylori Antigen and Antibodies revealed (63% human, 50% dogs) and (87% human, 90% dogs) respectively were positive. Genotyping of H. pylori based on 16S rRNA gene showed 54.5% of human and 35% of dogs were positive. Immunohistochemistry revealed strong expression of CD44 in H. pylori- associated gastric cancer cases, MMP-2 expression was observed in all neoplastic lesions associated with H. pylori infection. Conclusion: H. pylori infection affects gastric mucosa and induces changes in gastric stem cells altering their differentiation and increased expression of MMP’s and CD44with a resultant potentiation of oncogenic alteration. In addition the up-regulation of both markers could be an instrumental to interpret the origination of gastric cancer.

Download Full-text

The correlation between lncRNAs and Helicobacter pylori in gastric cancer

Pathogens and Disease ◽

10.1093/femspd/ftaa004 ◽

2019 ◽

Vol 77 (9) ◽

Author(s):

Narges Dastmalchi ◽

Seyed Mahdi Banan Khojasteh ◽

Mirsaed Miri Nargesi ◽

Reza Safaralizadeh

Keyword(s):

Gastric Cancer ◽

Helicobacter Pylori ◽

Molecular Mechanisms ◽

Gastrointestinal Diseases ◽

Mechanisms Of Action ◽

Molecular Pathways ◽

Gastric Diseases ◽

Non Coding Rnas ◽

H Pylori ◽

The Relationship

ABSTRACT Helicobacter pylori infection performs a key role in gastric tumorigenesis. Long non-coding RNAs (lncRNAs) have demonstrated a great potential to be regarded as effective malignancy biomarkers for various gastrointestinal diseases including gastric cancer (GC). The present review highlights the relationship between lncRNAs and H. pylori in GC. Several studies have examined not only the involvement of lncRNAs in H. pylori-associated GC progression but also their molecular mechanisms of action. Among the pertinent studies, some have addressed the effects of H. pylori infection on modulatory networks of lncRNAs, while others have evaluated the effects of changes in the expression level of lncRNAs in H. pylori-associated gastric diseases, especially GC. The relationship between lncRNAs and H. pylori was found to be modulated by various molecular pathways.

Download Full-text