Sialic acid-based strategies for the prevention and treatment of Helicobacter pylori infection: Emerging trends in food industry

Beyond antibiotics: exploring multifaceted approaches to combat bacterial resistance in the modern era: a comprehensive review

Antibiotics represent one of the most significant medical breakthroughs of the twentieth century, playing a critical role in combating bacterial infections. However, the rapid emergence of antibiotic resistance has become a major global health crisis, significantly complicating treatment protocols. This paper provides a narrative review of the current state of antibiotic resistance, synthesizing findings from primary research and comprehensive review articles to examine the various mechanisms bacteria employ to counteract antibiotics. One of the primary sources of antibiotic resistance is the improper use of antibiotics in the livestock industry. The emergence of drug-resistant microorganisms from human activities and industrial livestock production has presented significant environmental and public health concerns. Today, resistant nosocomial infections occur following long-term hospitalization of patients, causing the death of many people, so there is an urgent need for alternative treatments. In response to this crisis, non-antibiotic therapeutic strategies have been proposed, including bacteriophages, probiotics, postbiotics, synbiotics, fecal microbiota transplantation (FMT), nanoparticles (NPs), antimicrobial peptides (AMPs), antibodies, traditional medicines, and the toxin-antitoxin (TA) system. While these approaches offer innovative solutions for addressing bacterial infections and preserving the efficacy of antimicrobial therapies, challenges such as safety, cost-effectiveness, regulatory hurdles, and large-scale implementation remain. This review examines the potential and limitations of these strategies, offering a balanced perspective on their role in managing bacterial infections and mitigating the broader impact of antibiotic resistance.

Enhancement of host defense against Helicobacter pylori infection through modulation of the gastrointestinal microenvironment by Lactiplantibacillus plantarum Lp05

Objective

This study aimed to assess the impact of Lactiplantibacillus plantarum Lp05 (Lp05) on the gastrointestinal microbiome and pathophysiological status of mice infected with Helicobacter pylori (H. pylori), exploring its potential as a probiotic treatment for H. pylori infections.

Methods

In vitro, the interaction between Lp05 and H. pylori was analyzed using laser confocal and scanning electron microscopy. In vivo, C57BL/6 mice infected with H. pylori were treated with Lp05 and divided into six groups: control, model, quadruple therapy, and three dosage levels of Lp05 (2×107, 2×108, 2×109 CFU/mouse/day). Over six weeks, the impact of Lp05 on the gastrointestinal microbiome and physiological markers was assessed. Measurements included digestive enzymes (α-amylase, pepsin, cellulase), inflammatory markers (interleukin-17A, interleukin-23, interleukin-10, interferon-β, interferon-γ, FoxP3, endothelin, IP-10, TGF-β1), oxidative stress markers (catalase, malondialdehyde, superoxide dismutase, myeloperoxidase), and tissue pathology (via modified Warthin-Starry silver and H&E staining). Microbial community structure in the stomach and intestines was evaluated through 16S rRNA gene sequencing.

Results

In vitro studies showed Lp05 and H. pylori formed co-aggregates, with Lp05 potentially disrupting H. pylori cell structure, reducing its stomach colonization. In vivo, Lp05 significantly lowered gastric mucosal urease activity and serum H. pylori-IgG antibody levels in infected mice (p < 0.01). It also mitigated pathological changes in the stomach and duodenum, decreased inflammatory responses (ET, IL-17A, IL-23, TGF-beta1, and IP-10, p < 0.01 for all), and enhanced antioxidant enzyme activities (CAT and SOD, p < 0.01) while reducing MDA and MPO levels (p < 0.01), combating oxidative stress from H. pylori infection. Lp05 treatment significantly modified the intestinal and gastric microbiota, increasing beneficial bacteria like Lactobacillus and Ligilactobacillus, and decreasing harmful bacteria such as Olsenella, linked to pathological conditions.

Conclusion

Lp05 effectively modulates the gastrointestinal microbiome, reduces inflammation and oxidative stress, and suppresses H. pylori, promising for probiotic therapies with further research needed to refine its clinical use.

Four novel anti-adhesive activity peptides against Helicobacter pylori derived from rice bran protein: release, identification and anti-adhesive mechanisms elucidation

H. pylori is a highly pathogenic and prevalent pathogen that is a class I carcinogen. More than 50% of the world's population is infected with H. pylori. An anti-adhesive strategy is an effective way to antagonize H. pylori infection, which does not cause H. pylori resistance and is safer compared to antibiotic therapy. In the present study, to obtain rice bran protein-derived anti-adhesive activity peptides against H. pylori, an efficient enzymatic hydrolysis system was established, and it was found that rice bran protein hydrolysate prepared under specific conditions possessed anti-adhesive activity against H. pylori. The anti-adhesive activity of rice bran protein hydrolysate (RPH) was 43.74 ± 1.12% (4 mg mL-1), and gastric digestion (RPHA) had no significant effect on its activity. Hydrophobic amino acids and aromatic amino acids were important for its anti-adhesive activity. Further, 284 peptide sequences with potential anti-adhesive activity were isolated and identified from RPHA. Combined with molecular docking results, four novel anti-adhesive activity peptides were finally screened, namely LS5 (LSFRL), SN8 (SNTPGMVY), VV7 (VVNFGNL) and PV9 (PVLWGVPKG). Among them, PV9 showed the highest anti-adhesive activity of 59.64 ± 2.00% (4 mg mL-1). These four peptides could bind H. pylori adhesins BabA and SabA, occupying the binding sites of cell receptors and acting as anti-adhesion agents. In conclusion, four rice bran protein-derived anti-adhesive activity peptides against H. pylori can be used for the development of novel functional foods antagonizing H. pylori infection.

LOX-1 acts as an N6-methyladenosine-regulated receptor for Helicobacter pylori by binding to the bacterial catalase

The role of N6-methyladenosine (m6A) modification of host mRNA during bacterial infection is unclear. Here, we show that Helicobacter pylori infection upregulates host m6A methylases and increases m6A levels in gastric epithelial cells. Reducing m6A methylase activity via hemizygotic deletion of methylase-encoding gene Mettl3 in mice, or via small interfering RNAs targeting m6A methylases, enhances H. pylori colonization. We identify LOX-1 mRNA as a key m6A-regulated target during H. pylori infection. m6A modification destabilizes LOX-1 mRNA and reduces LOX-1 protein levels. LOX-1 acts as a membrane receptor for H. pylori catalase and contributes to bacterial adhesion. Pharmacological inhibition of LOX-1, or genetic ablation of Lox-1, reduces H. pylori colonization. Moreover, deletion of the bacterial catalase gene decreases adhesion of H. pylori to human gastric sections. Our results indicate that m6A modification of host LOX-1 mRNA contributes to protection against H. pylori infection by downregulating LOX-1 and thus reducing H. pylori adhesion.

Helicobacter pylori infection in humans and phytotherapy, probiotics, and emerging therapeutic interventions: a review

The global prevalence of Helicobacter pylori (H. pylori) infection remains high, indicating a persistent presence of this pathogenic bacterium capable of infecting humans. This review summarizes the population demographics, transmission routes, as well as conventional and novel therapeutic approaches for H. pylori infection. The prevalence of H. pylori infection exceeds 30% in numerous countries worldwide and can be transmitted through interpersonal and zoonotic routes. Cytotoxin-related gene A (CagA) and vacuolar cytotoxin A (VacA) are the main virulence factors of H. pylori, contributing to its steep global infection rate. Preventative measures should be taken from people's living habits and dietary factors to reduce H. pylori infection. Phytotherapy, probiotics therapies and some emerging therapies have emerged as alternative treatments for H. pylori infection, addressing the issue of elevated antibiotic resistance rates. Plant extracts primarily target urease activity and adhesion activity to treat H. pylori, while probiotics prevent H. pylori infection through both immune and non-immune pathways. In the future, the primary research focus will be on combining multiple treatment methods to effectively eradicate H. pylori infection.

Recent advances on N-acetylneuraminic acid: Physiological roles, applications, and biosynthesis

N-Acetylneuraminic acid (Neu5Ac), the most common type of Sia, generally acts as the terminal sugar in cell surface glycans, glycoconjugates, oligosaccharides, lipo-oligosaccharides, and polysaccharides, thus exerting numerous physiological functions. The extensive applications of Neu5Ac in the food, cosmetic, and pharmaceutical industries make large-scale production of this chemical desirable. Biosynthesis which is associated with important application potential and environmental friendliness has become an indispensable approach for large-scale synthesis of Neu5Ac. In this review, the physiological roles of Neu5Ac was first summarized in detail. Second, the safety evaluation, regulatory status, and applications of Neu5Ac were discussed. Third, enzyme-catalyzed preparation, whole-cell biocatalysis, and microbial de novo synthesis of Neu5Ac were comprehensively reviewed. In addition, we discussed the main challenges of Neu5Ac de novo biosynthesis, such as screening and engineering of key enzymes, identifying exporters of intermediates and Neu5Ac, and balancing cell growth and biosynthesis. The corresponding strategies and systematic strategies were proposed to overcome these challenges and facilitate Neu5Ac industrial-scale production.

Dietary sialic acids: distribution, structure, and functions

Sialic acids (Sias), a group of over 50 structurally distinct acidic saccharides on the surface of all vertebrate cells, are neuraminic acid derivatives. They serve as glycan chain terminators in extracellular glycolipids and glycoproteins. In particular, Sias have significant implications in cell-to-cell as well as host-to-pathogen interactions and participate in various biological processes, including neurodevelopment, neurodegeneration, fertilization, and tumor migration. However, Sia is also present in some of our daily diets, particularly in conjugated form (sialoglycans), such as those in edible bird's nest, red meats, breast milk, bovine milk, and eggs. Among them, breast milk, especially colostrum, contains a high concentration of sialylated oligosaccharides. Numerous reviews have concentrated on the physiological function of Sia as a cellular component of the body and its relationship with the occurrence of diseases. However, the consumption of Sias through dietary sources exerts significant influence on human health, possibly by modulating the gut microbiota's composition and metabolism. In this review, we summarize the distribution, structure, and biological function of particular Sia-rich diets, including human milk, bovine milk, red meat, and egg.

Role of ST6GAL1 and ST6GAL2 in subversion of cellular signaling during enteroaggregative Escherichia coli infection of human intestinal epithelial cell lines

Emerging evidence have suggested that aberrant sialylation on cell-surface carbohydrate architecture may influence host-pathogen interactions. The α2,6-sialyltransferase (ST) enzymes were found to alter the glycosylation pattern of the pathogen-infected host cell-surface proteins, which could facilitate its invasion. In this study, we assessed the role of specific α2,6-ST enzymes in the regulation of enteroaggregative E. coli (EAEC)-induced cell signaling pathways in human intestinal epithelial cells. EAEC-induced expression of α2,6-ST family genes in HCT-15 and INT-407 cell lines was assessed at mRNA level by qRT-PCR. Specific esi-RNA was used to silence the target ST-gene in each of the EAEC-infected cell type. Subsequently, the role of these enzymes in regulation of EAEC-induced cell signaling pathways was unraveled by analyzing the expression of MAPkinases (ERK1/2, p38, JNK) and transcription factors (NFκB, cJun, cFos, STAT) at mRNA and protein levels by qRT-PCR and western immunoblotting, respectively, expression of selected sialoglycoproteins by western immunoblotting along with the secretory IL-8 response using sandwich ELISA. ST6GAL-1 and ST6GAL-2 were efficiently silenced in EAEC-infected HCT-15 and INT-407 cells, respectively. Significant reduction in EAEC-induced activation of MAPKs, transcription factors, sialoglycoproteins, and IL-8 secretion was noted in ST-silenced cells in comparison to the respective control cells. We propose that ST6GAL-1 and ST6GAL-2 are quintessential for EAEC-induced stimulation of MAPK-mediated pathways, resulting in activation of transcription factors, leading to an inflammatory response in the human intestinal epithelial cells. Our study may be helpful to design better therapeutic strategies to control EAEC- infection. KEY POINTS: • EAEC induces α2,6-sialyltransferase (ST) upregulation in intestinal epithelial cells • Target STs (ST6GAL-1 & ST6GAL-2) were efficiently silenced using specific esiRNAs • Expression of MAPKs, transcription factors & IL-8 was reduced in ST silenced cells.

Host Cell Antimicrobial Responses against Helicobacter pylori Infection: From Biological Aspects to Therapeutic Strategies

The colonization of Helicobacter pylori (H. pylori) in human gastric mucosa is highly associated with the occurrence of gastritis, peptic ulcer, and gastric cancer. Antibiotics, including amoxicillin, clarithromycin, furazolidone, levofloxacin, metronidazole, and tetracycline, are commonly used and considered the major treatment regimens for H. pylori eradication, which is, however, becoming less effective by the increasing prevalence of H pylori resistance. Thus, it is urgent to understand the molecular mechanisms of H. pylori pathogenesis and develop alternative therapeutic strategies. In this review, we focus on the virulence factors for H. pylori colonization and survival within host gastric mucosa and the host antimicrobial responses against H. pylori infection. Moreover, we describe the current treatments for H. pylori eradication and provide some insights into new therapeutic strategies for H. pylori infection.

Detection of sialic acid using boronic-acid-functionalized metal organic framework UiO-66-NH2@B(OH)2

Sialic acid (SA) is a crucial component of glycoproteins and glycolipids on the cellular membrane, which is essential for maintaining the function of cell membranes, such as cell recognition and communication. Simultaneously, sialic acid plays a significant role in many physiological and pathological processes. Hence, it is urgent to develop a simple and sensitive strategy for determining sialic acid. In this work, a new metal-organic framework called UiO-66-NH₂@B(OH)₂ has been designed and synthesized for the recognition and detection of sialic acid. The boronic acid functional group in UiO-66-NH₂@B(OH)₂ can bind to a diol moiety of the glycerol side chain of sialic acid, which will attenuate or even quench the fluorescence of UiO-66-NH₂@B(OH)₂, thus opening a new road to detect sialic acid. Based on the measurement results, sialic acid can be quantitatively measured in a linear range of 0.05-2.5 mmoL/L with the UiO-66-NH₂@B(OH)₂ probe. The detection limit of sialic acid is as low as 0.025 mmol/L. Furthermore, the boronic-acid functionalized probe UiO-66-NH₂@B(OH)₂ displays high sensitivity and high selectivity to recognize the sialic acid in mouse serum samples. Therefore, the developed UiO-66-NH₂@B(OH)₂ can be used as a promising probe to identify and detect sialic acid in the practical application.