Protein signature characterizing Helicobacter pylori strains of patients with autoimmune atrophic gastritis, duodenal ulcer and gastric cancer

Differential Proteomics of Helicobacter pylori Isolates from Gastritis, Ulcer, and Cancer Patients: First Study from Northwest Pakistan

Background and Objective: Helicobacter pylori is a human-stomach-dwelling organism that causes many gastric illnesses, including gastritis, ulcer, and gastric cancer. The purpose of the study was to perform differential proteomic analysis on H. pylori isolates from gastritis, ulcer, and gastric cancer patients. Materials and Methods: H. pylori was isolated from antrum and fundus biopsies obtained from patients who visited the Department of Gastroenterology. Using nano-LC-QTOF MS/MS analysis, differentially regulated proteins were identified through proteome profiling of pooled samples of H. pylori isolated from gastritis, ulcer, and gastric cancer patients. Antigenic scores and cellular localization of proteins were determined using additional prediction tools. Results: A total of 14 significantly regulated proteins were identified in H. pylori isolated from patients with either gastritis, ulcer, or gastric cancer. Comparative analysis of groups revealed that in the case of cancer vs. gastritis, six proteins were overexpressed, out of which two proteins, including hydrogenase maturation factor (hypA) and nucleoside diphosphate kinase (ndk) involved in bacterial colonization, were only upregulated in isolates from cancer patients. Similarly, in cancer vs. ulcer, a total of nine proteins were expressed. Sec-independent protein translocase protein (tatB), involved in protein translocation, and pseudaminic acid synthase I (pseI), involved in the synthesis of functional flagella, were upregulated in cancer, while hypA and ndk were downregulated. In ulcer vs. gastritis, eight proteins were expressed. In this group, tatB was overexpressed. A reduction in thioredoxin peroxidase (bacterioferritin co-migratory protein (bcp)) was observed in ulcer vs. gastritis and cancer vs. ulcer. Conclusion: Our study suggested three discrete protein signatures, hypA, tatB, and bcp, with differential expression in gastritis, ulcer, and cancer. Protein expression profiles of H. pylori isolated from patients with these gastric diseases will help to understand the virulence and pathogenesis of H. pylori.

Applications of Tandem Mass Spectrometry (MS/MS) in Protein Analysis for Biomedical Research

Mass Spectrometry (MS) allows the analysis of proteins and peptides through a variety of methods, such as Electrospray Ionization-Mass Spectrometry (ESI-MS) or Matrix-Assisted Laser Desorption Ionization-Mass Spectrometry (MALDI-MS). These methods allow identification of the mass of a protein or a peptide as intact molecules or the identification of a protein through peptide-mass fingerprinting generated upon enzymatic digestion. Tandem mass spectrometry (MS/MS) allows the fragmentation of proteins and peptides to determine the amino acid sequence of proteins (top-down and middle-down proteomics) and peptides (bottom-up proteomics). Furthermore, tandem mass spectrometry also allows the identification of post-translational modifications (PTMs) of proteins and peptides. Here, we discuss the application of MS/MS in biomedical research, indicating specific examples for the identification of proteins or peptides and their PTMs as relevant biomarkers for diagnostic and therapy.

Helicobacter pylori Infection in Malnourished Children in Lagos

Background/Aim:

Helicobacter pylori infection is acquired in childhood, but there are conflicting reports on malnutrition and the infection. This study aimed to determine the prevalence of H. pylori infection among malnourished children and highlight the socioeconomic (SE) and clinical factors associated with the infection.

Methodology:

This was a descriptive cross-sectional study of 122 malnourished children and 120 healthy controls. Anthropometry was done for all the study participants, and the H. pylori status was determined with the use of monoclonal stool antigen test in all the participants. Logistic regression analysis was used to determine the factors that could predict the occurrence of the infection in the children.

Results:

Seventy percent (70.8%) of the malnourished children had moderate malnutrition, whereas 29.2% were severely malnourished. The prevalence of H. pylori in the malnourished children was 22.8% compared to 32.5% in the controls (P = 0.09). The infection was most prevalent in toddlers (60.7%). The SE class was significantly related to the infection (P = 0.01) and about a fifth (21.3%) of the malnourished children who belonged to the low SE class were H. pylori positive compared to 9.2% of the controls. About 64.3% of the malnourished children with H. pylori infection had fever and 25.8% had diarrhea. Multivariate analysis showed that stunting was significantly related to the infection (P = 0.02).

Conclusion:

H. pylori infection was prevalent among the toddlers and was significantly associated with stunting in this cohort of malnourished children. Screening of children for the infection is still advocated, and infected children should be referred for appropriate treatment and follow-up. The relationship between SE class and the infection still requires further research.

The Prevalence of Helicobacter Pylori babA, homB, aspA, and sabA Genes and Its Relationship with Clinical Outcomes in Turkey

BACKGROUND AND AIMS

The cag A and vac A genes of Helicobacter pylori (H. pylori) are closely associated with the pathogenicity of bacteria. However, the significance of H. pylori babA, homB, aspA, and sabA genes is not clear in phenotypic characteristics of virulence. This study aimed to investigate the frequency and importance of these genes in patients with H. pylori positive peptic ulcer (PU).

MATERIALS AND METHODS

Patients with a PU or nonulcer dyspepsia (NUD) based on the upper gastrointestinal (UGI) endoscopy findings were included in the study. Biopsy samples from antrum and corpus were cultured into Columbia agar. H pylori were characterized by urease, catalase, oxidase test, and gram staining. Genomic DNA was extracted and stored. The babA, homB, aspA, and sabA genes were determined by using polymerase chain reaction analysis.

RESULTS

A total 214 patients were included (99 PU and 115 NUD) and H. pylori could be isolated in 82 patients (36 PU and 46 NUD). The frequency of the babA (25% vs. 15.2%, p=0.25), homB (2.7% vs. 4.3%, p=1), aspA (69.4% vs. 73.9%, p=0.2), and sabA (2.7% vs. 10.8%, p=0.88) genotypes was not different between PU and NUD patients. There were some correlations between the presences of these genes.

CONCLUSION

This study managed to determine babA, homB, aspA, and sabA genes of H. pylori by PCR. However, the frequency of these factors was not different in patients with PU and NUD. There is no role of babA, homB, aspA, and sabA genes for the development of peptic ulcer in Turkish population.

Polymorphism in Toll-Like Receptors and Helicobacter Pylori Motility in Autoimmune Atrophic Gastritis and Gastric Cancer

Autoimmune atrophic gastritis (AAG) is associated with an increased risk of certain types of gastric cancer (GC). Helicobacter pylori (H. pylori) infection may have a role in the induction and/or maintenance of AAG and GC. Toll-like receptors (TLR) are essential for H. pylori recognition and subsequent innate and adaptive immunity responses. This study therefore aimed to characterize TLR polymorphisms, and features of bacterial flagellin A in samples from patients with AAG (n = 67), GC (n = 114) and healthy donors (HD; n = 97). TLR5 rs5744174 C/C genotype was associated with GC, lower IgG anti H. pylori response and a higher H. pylori flagellin A abundance and motility. In a subset of patients with AAG, H. pylori strains showed a reduction of the flagellin A abundance and a moderate motility compared with strains from GC patients, a prerequisite for active colonization of the deeper layers of the mucosa, host immune response and inflammation. TLR9 rs5743836 T allele showed an association with serum gastrin G17. In conclusion, our study suggests that alterations of flaA protein, moderate motility in H. pylori and two polymorphisms in TLR5 and TLR9 may favor the onset of AAG and GC, at least in a subset of patients. These findings corroborate the function of pathogen–host cell interactions and responses, likely influencing the pathogenetic process.