MicroRNA signatures in Helicobacter pylori-infected gastric mucosa

Protective effect of dimethyl fumarate against ethanol-provoked gastric ulcers in rats via regulation of HMGB1/TLR4/NF-κB, and PPARγ/SIRT1/Nrf2 pathways: Involvement of miR-34a-5p

Aberration of the gastric mucosal barrier homeostasis circuit is one of the key features linked to the onset of gastric ulcers (GU). This work aimed to inspect the gastroprotective influence of dimethyl fumarate (DMF) on ethanol-induced GU in rats and to decipher the possible mechanisms entailed. Rats were pretreated with either DMF (80 mg/kg) or omeprazole (OMP) (20 mg/kg) by oral gavage for 2 weeks. After 24 h of starvation, ethanol (5 ml/kg, oral) was employed to trigger GU in rats, while carboxymethyl cellulose (CMC) was used as a control. Ethanol notably elevated both macroscopic and microscopic gastric damage. DMF and OMP exhibited similar effects on gastric ulcer healing. DMF intervention led to a substantial improvement in gastric insults. DMF significantly reduced ethanol-triggered gastric lesions, as manifested by decreased gastric secretion, acidity, ulcer surface area percent, reduced leukocyte incursion, and increased mucus percent. DMF upregulated miR-34a-5p expression concomitant with the suppression of high mobility group box1 (HMGB1) and inflammatory responses in gastric mucosal homogenate. DMF improved GU by restoring reduced antioxidant defense mechanisms through the coactivation of nuclear factor erythroid 2-related factor-2 (Nrf2), peroxisome proliferator-activated receptor gamma (PPARγ), and sirtuin1 (SIRT1), indicating the protective role of the PPARγ/SIRT1/Nrf2 pathway. Intriguingly, DMF mitigated apoptosis in ethanol-elicited GU. Taken together, this research implies the potential for the repurposing of DMF as an innovative gastroprotective medication to reestablish the balance of the gastric mucosal barrier via the attenuation of gastric inflammation, oxidative stress, and apoptosis.

The role of microRNAs in the gastric cancer tumor microenvironment

BACKGROUND

Gastric cancer (GC) is one of the deadliest malignant tumors with unknown pathogenesis. Due to its treatment resistance, high recurrence rate, and lack of reliable early detection techniques, a majority of patients have a poor prognosis. Therefore, identifying new tumor biomarkers and therapeutic targets is essential. This review aims to provide fresh insights into enhancing the prognosis of patients with GC by summarizing the processes through which microRNAs (miRNAs) regulate the tumor microenvironment (TME) and highlighting their critical role in the TME.

MAIN TEXT

A comprehensive literature review was conducted by focusing on the interactions among tumor cells, extracellular matrix, blood vessels, cancer-associated fibroblasts, and immune cells within the GC TME. The role of noncoding RNAs, known as miRNAs, in modulating the TME through various signaling pathways, cytokines, growth factors, and exosomes was specifically examined. Tumor formation, metastasis, and therapy in GC are significantly influenced by interactions within the TME. miRNAs regulate tumor progression by modulating these interactions through multiple signaling pathways, cytokines, growth factors, and exosomes. Dysregulation of miRNAs affects critical cellular processes such as cell proliferation, differentiation, angiogenesis, metastasis, and treatment resistance, contributing to the pathogenesis of GC.

CONCLUSIONS

miRNAs play a crucial role in the regulation of the GC TME, influencing tumor progression and patient prognosis. By understanding the mechanisms through which miRNAs control the TME, potential biomarkers and therapeutic targets can be identified to improve the prognosis of patients with GC.

Mycobacterium tuberculosis and host interactions in the manifestation of tuberculosis

The final step of epigenetic processes is changing the gene expression in a new microenvironment in the body, such as neuroendocrine changes, active infections, oncogenes, or chemical agents. The case of tuberculosis (TB) is an outcome of Mycobacterium tuberculosis (M.tb) and host interaction in the manifestation of active and latent TB or clearance. This comprehensive review explains and interprets the epigenetics findings regarding gene expressions on the host-pathogen interactions in the development and progression of tuberculosis. This review introduces novel insights into the complicated host-pathogen interactions, discusses the challengeable results, and shows the gaps in the clear understanding of M.tb behavior. Focusing on the biological phenomena of host-pathogen interactions, the epigenetic changes, and their outcomes provides a promising future for developing effective TB immunotherapies when converting gene expression toward appropriate host immune responses gradually becomes attainable. Overall, this review may shed light on the dark sides of TB pathogenesis as a life-threatening disease. Therefore, it may support effective planning and implementation of epigenetics approaches for introducing proper therapies or effective vaccines.

MicroRNAs in Helicobacter pylori-infected gastric cancer: Function and clinical application

Gastric cancer (GC) is the leading cause of cancer-related death worldwide, and it is associated with a combination of genetic, environmental, and microbial risk factors. Helicobacter pylori (H. pylori) is classified as a type I carcinogen, however, the exact regulatory mechanisms underlying H. pylori-induced GC are incompletely defined. MicroRNAs (miRNAs), one of small non-coding RNAs, negatively regulate gene expression through binding to their target genes. Dysregulation of miRNAs is crucial in human cancer. A noteworthy quantity of aberrant miRNAs induced by H. pylori through complex regulatory networks have been identified. These miRNAs substantially affect genetic instability, cell proliferation, apoptosis, invasion, metastasis, autophagy, chemoresistance, and the tumor microenvironment, leading to GC development and progression. Importantly, some H. pylori-associated miRNAs hold promise as therapeutic tools and biomarkers for GC prevention, diagnosis, and prognosis. Nonetheless, clinical application of miRNAs remains in its infancy with multiple issues, including sensitivity and specificity, stability, reliable delivery systems, and off-target effects. Additional research on the specific molecular mechanisms and more clinical data are still required. This review investigated the biogenesis, regulatory mechanisms, and functions of miRNAs in H. pylori-induced GC, offering novel insights into the potential clinical applications of miRNA-based therapeutics and biomarkers.

Non-Invasive Markers for the Detection of Gastric Precancerous Conditions

Gastric cancer (GC) is still one of the most prevalent cancers worldwide, with a high mortality rate, despite improvements in diagnostic and therapeutic strategies. To diminish the GC burden, a modification of the current diagnostic paradigm, and especially endoscopic diagnosis of symptomatic individuals, is necessary. In this review article, we present a broad review and the current knowledge status on serum biomarkers, including pepsinogens, gastrin, Gastropanel®, autoantibodies, and novel biomarkers, allowing us to estimate the risk of gastric precancerous conditions (GPC)-atrophic gastritis and gastric intestinal metaplasia. The aim of the article is to emphasize the role of non-invasive testing in GC prevention. This comprehensive review describes the pathophysiological background of investigated biomarkers, their status and performance based on available data, as well as their clinical applicability. We point out future perspectives of non-invasive testing and possible new biomarkers opportunities.

The Most Recent Insights into the Roots of Gastric Cancer

Helicobacter pylori (H. pylori) is the most common bacterial infection worldwide, usually being acquired during childhood, and its persistence into adulthood represents one of the main contributors of gastric carcinogenesis. Based on these statements, it would be of great importance to know if the most early premalignant transformation occurs in children or later since, this would enable the development of effective anti-tumorigenesis strategies. The interplay between H. pylori virulence factors, the host's responses modified by this infection, and the gastric microecology are complex and eventually lead to the development of gastric cancer in susceptible individuals. Several biomarkers were identified as major contributors of this long-lasting process, such as pepsinogens, gastrin 17, lipid-, glucose- and iron-metabolism parameters, immunity players, aberrant bacterial DNA methylation, H. pylori virulence factors, and hallmarks of gastric dysbiosis. Several of these biomarkers were also identified in children with H. pylori infection, independently of the presence of premalignant lesions, which were also proven to be present in a subgroup of H. pylori-infected children, especially those carrying extremely virulent strains. Therefore, the most incipient premalignant gastric changes might indeed occur early during childhood, opening a promising research gate for further studies to delineate the border between infection and cancer.

Helicobacter pylori promotes gastric fibroblast proliferation and migration by expulsing exosomal miR-124-3p

Gastric fibroblasts (GFs) are direct targets of Helicobacter pylori (H. pylori). GFs infected with H. pylori exhibit marked changes in their morphology and biological behavior. However, the molecular mechanisms by which H. pylori regulates GFs remain unknown. In this study, we cocultured GFs with H. pylori for 48 h. As a result, GFs exhibited an elongated and spindle-shaped morphology. Further, cancer-associated fibroblast (CAF) biomarkers were increased, and related behaviors were significantly enhanced in H. pylori-activated GFs. The number of extracellular vesicles (EVs) secreted by H. pylori-activated GFs remarkably increased. The miR-124-3p level was increased in secreted EVs but decreased in the cytoplasm of H. pylori-activated GFs. Overexpression of miRNA-124-3p in the original GFs significantly suppressed their proliferation and migration. In addition, the migration-promoting effects of H. pylori-activated GFs were suppressed by miR-124-3p and GW4869, which blocked EV generation. Finally, pull-down and luciferase assays revealed that SNAI2 is a target of miR-124-3p. The migration-inhibitory effects of GFs treated with miR-124-3p were eliminated by the overexpression of SNAI2, and the upregulation of SNAI2 in H. pylori-activated GFs was partially alleviated by miR-124-3p or GW4869. Overall, H. pylori infection promotes the proliferation and migration of GFs by accelerating the expulsion of EVs carrying miRNA-124-3p, a SNAI2 inhibitor.

Targeting epigenetic deregulations for the management of esophageal carcinoma: recent advances and emerging approaches

Ranking from seventh in incidence to sixth in mortality, esophageal carcinoma is considered a severe malignancy of food pipe. Later-stage diagnosis, drug resistance, and a high mortality rate contribute to its lethality. Esophageal squamous cell carcinoma and esophageal adenocarcinoma are the two main histological subtypes of esophageal carcinoma, with squamous cell carcinoma alone accounting for more than eighty percent of its cases. While genetic anomalies are well known in esophageal cancer, accountability of epigenetic deregulations is also being explored for the recent two decades. DNA methylation, histone modifications, and functional non-coding RNAs are the crucial epigenetic players involved in the modulation of different malignancies, including esophageal carcinoma. Targeting these epigenetic aberrations will provide new insights into the development of biomarker tools for risk stratification, early diagnosis, and effective therapeutic intervention. This review discusses different epigenetic alterations, emphasizing the most significant developments in esophageal cancer epigenetics and their potential implication for the detection, prognosis, and treatment of esophageal carcinoma. Further, the preclinical and clinical status of various epigenetic drugs has also been reviewed.

Role of salivary miRNAs in the diagnosis of gastrointestinal disorders: a mini-review of available evidence

MiRNAs are short, non-coding RNA molecules, which are involved in the regulation of gene expression and which play an important role in various biological processes, including inflammation and cell cycle regulation. The possibility of detecting their extracellular expression, within body fluids, represented the main background for their potential use as non-invasive biomarkers of various diseases. Salivary miRNAs particularly gained interest recently due to the facile collection of stimulated/unstimulated saliva and their stability among healthy subjects. Furthermore, miRNAs seem to represent biomarker candidates of gastrointestinal disorders, with miRNA-based therapeutics showing great potential in those conditions. This review aimed to highlight available evidence on the role of salivary miRNAs in different gastrointestinal conditions. Most salivary-based miRNA studies available in the literature that focused on pathologies of the gastrointestinal tract have so far been conducted on pancreatic cancer patients and delivered reliable results. A few studies also showed the diagnostic utility of salivary miRNAs in conditions such as esophagitis, esophageal cancer, colorectal cancer, or inflammatory bowel disease. Moreover, several authors showed that salivary miRNAs may confidently be used as biomarkers of gastric cancer, but the use of salivary miRNA candidates in gastric inflammation and pre-malignant lesions, essential stages of Correa's cascade, is still put into question. On the other hand, besides miRNAs, other salivary omics have shown biomarker potential in gastro-intestinal conditions. The limited available data suggest that salivary miRNAs may represent reliable biomarker candidates for gastrointestinal conditions. However, their diagnostic potential requires validation through future research, performed on larger cohorts.

Helicobacter pylori infection induces abnormal expression of pro-angiogenic gene ANGPT2 and miR-203a in AGS gastric cell line

Helicobacter pylori colonizes the stomach and induces an inflammatory response that can develop into gastric pathologies including cancer. The infection can alter the gastric vasculature by the deregulation of angiogenic factors and microRNAs. In this study, we investigate the expression level of pro-angiogenic genes (ANGPT2, ANGPT1, receptor TEK), and microRNAs (miR-135a, miR-200a, miR-203a) predicted to regulate those genes, using H. pylori co-cultures with gastric cancer cell lines. In vitro infections of different gastric cancer cell lines with H. pylori strains were performed, and the expression of ANGPT1, ANGPT2, and TEK genes, and miR-135a, miR-200a, and miR-203a, was quantified after 24 h of infection (h.p.i.). We performed a time course experiment of H. pylori 26695 infections in AGS cells at 6 different time points (3, 6, 12, 28, 24, and 36 h.p.i.). The angiogenic response induced by supernatants of non-infected and infected cells at 24 h.p.i. was evaluated in vivo, using the chicken chorioallantoic membrane (CAM) assay. In response to infection, ANGPT2 mRNA was upregulated at 24 h.p.i, and miR-203a was downregulated in AGS cells co-cultured with different H. pylori strains. The time course of H. pylori 26695 infection in AGS cells showed a gradual decrease of miR-203a expression concomitant with an increase of ANGPT2 mRNA and protein expression. Expression of ANGPT1 and TEK mRNA or protein could not be detected in any of the infected or non-infected cells. CAM assays showed that the supernatants of AGS-infected cells with 26695 strain induced a significantly higher angiogenic and inflammatory response. Our results suggest that H. pylori could contribute to the process of carcinogenesis by downregulating miR-203a, which further promotes angiogenesis in gastric mucosa by increasing ANGPT2 expression. Further investigation is needed to elucidate the underlying molecular mechanisms.

Chromatin and noncoding RNA-mediated mechanisms of gastric tumorigenesis

Gastric cancer (GC) is one of the most common and deadly cancers in the world. It is a multifactorial disease highly influenced by environmental factors, which include radiation, smoking, diet, and infectious pathogens. Accumulating evidence suggests that epigenetic regulators are frequently altered in GC, playing critical roles in gastric tumorigenesis. Epigenetic regulation involves DNA methylation, histone modification, and noncoding RNAs. While it is known that environmental factors cause widespread alterations in DNA methylation, promoting carcinogenesis, the chromatin- and noncoding RNA-mediated mechanisms of gastric tumorigenesis are still poorly understood. In this review, we focus on discussing recent discoveries addressing the roles of histone modifiers and noncoding RNAs and the mechanisms of their interactions in gastric tumorigenesis. A better understanding of epigenetic regulation would likely facilitate the development of novel therapeutic approaches targeting specific epigenetic regulators in GC.

Uncovering the role of microRNA671-5p/CDCA7L/monoamine oxidase-A signaling in Helicobacter pylori mediated apoptosis in gastric epithelial cells

Helicobacter pylori is a gram-negative microaerophilic bacterium and is associated with gastrointestinal diseases ranging from peptic ulcer and gastritis to gastric cancer and mucosa-associated lymphoid tissue lymphoma. In our laboratory, the transcriptomes and miRnomes of AGS cells infected with H. pylori have been profiled, and an miRNA-mRNA network has been constructed. MicroRNA 671-5p is upregulated during H. pylori infection of AGS cells or of mice. In this study, the role of miR-671-5p during infection has been investigated. It has been validated that miR-671-5p targets the transcriptional repressor CDCA7L, which is downregulated during infection (in vitro and in vivo) concomitant with miR-671-5p upregulation. Further, it has been established that the expression of monoamine oxidase A (MAO-A) is repressed by CDCA7L, and that MAO-A triggers the generation of reactive oxygen species (ROS). Consequently, miR-671-5p/CDCA7L signaling is linked to the generation of ROS during H. pylori infection. Finally, it has been demonstrated that ROS-mediated caspase 3 activation and apoptosis that occurs during H. pylori infection, is dependent on the miR-671-5p/CDCA7L/MAO-A axis. Based on the above reports, it is suggested that targeting miR-671-5p could offer a means of regulating the course and consequences of H. pylori infection.

Functional gene polymorphisms and expression alteration of selected microRNAs and the risk of various gastric lesions in Helicobacter pylori-related gastric diseases

Background: Helicobacter pylori (Hp) persistent infection is an important pathogenic factor for a series of chronic gastric diseases from chronic gastritis to gastric cancer. Genetic and epigenetic abnormalities of microRNAs may play a vital role in the pathological evolution of gastric mucosa in Helicobacter pylori-related gastric diseases (HPGD). This study aimed to investigate the relationship between miR-146a, miR-196a2, miR-149, miR-499 and miR-27a gene single nucleotide polymorphisms (SNPs) and their expressions with pathological changes in gastric mucosa, and to further analyze the interactions between SNPs and Hp. Methods: Subjects in this study included patients diagnosed with HPGD and healthy controls. MiR-146a rs2910164, miR-196a2 rs11614913, miR-149 rs2292832, miR-499 rs3746444 and miR-27a rs895819 were genotyped by direct sequencing. Fluorescence quantitative PCR was used to detect microRNA expressions. Gene-gene and gene-environment interactions were evaluated by multifactor dimensionality reduction (MDR) method. Results: we found that frequency distribution of miR-196a2 rs11614913 CT genotype in gastric precancerous lesion (GPL) group and gastric cancer (GC) group was significantly higher than normal control (NOR) group [adjusted OR = 6.16, 95%CI (1.46-26.03); adjusted OR = 11.83, 95%CI (1.65-84.72), respectively]. CT genotype and C allele of miR-27a rs895819 were associated with increased risk of GC [adjusted OR = 10.14, 95%CI (2.25-45.77); adjusted OR = 3.71, 95%CI(1.46-9.44), respectively]. The MDR analysis results showed that the interaction between miR-196a2 rs11614913 and Hp was associated with the risk of GPL (p = 0.004). Meanwhile, the expression level of miR-196a2 in GC group was significantly higher than NOR, chronic inflammation (CI) and early precancerous lesion (EPL) groups among Hp-positive subjects. And expressions of miR-499 and miR-27a in GC group were both higher than EPL group. Also, miR-27a expression in GC group was higher than CI and gastric atrophy (GA) groups. Conclusion: miR-196a2 rs11614913 and miR-27a rs895819 may affect the genetic susceptibility to GPL or GC. MiR-196a2 rs11614913 and Hp have a synergistic effect in the occurrence and development of GPL. The up-regulation of miR-499, miR-196a2 and miR-27a expression caused by Hp infection may be an important mechanism of gastric carcinogenesis.

Differential Expression of Tissular miRNA-155 in Pediatric Gastritis

BACKGROUND

MicroRNA molecules, among them the intensely studied miRNA-155 (miR-155), are regarded as potential biomarkers of chronic gastric inflammation and premalignant lesion progression. However, literature data are scarce in terms of pediatric studies and in the evaluation of the predictive role of miRNA in early gastric inflammation. This study aims to assess the differential expression of miR-155 in relation to pediatric gastritis.

METHODS

The present research was conducted on 192 patients with chronic dyspeptic symptoms who underwent upper digestive endoscopy. Bioptic samples were harvested for histopathological analysis and tissue miR-155 depiction. MiR-155 expression analysis was carried out through quantitative real-time polymerase chain reaction (qRT-PCR). The study population was divided into two groups: controls (93 patients) and study group (99 patients) with inflammatory modifications.

RESULTS

MiR-155 expression was augmented in patients with gastritis but did not differ significantly from controls (p = 0.16). An increase in miR-155 expression was noted in relation to chronic gastritis, H. pylori infection, or increase in gastritis severity, but these variations were not important (p = 0.30, p = 0.44, and p = 0.45, respectively).

CONCLUSIONS

According to our study, pediatric gastritis increases, but does not greatly influence, miR-155 expression. Dynamic evaluation of miR-155 might enlighten its prognostic role in pediatric gastritis.

The role of non-coding RNA in the diagnosis and treatment of Helicobacter pylori-related gastric cancer, with a focus on inflammation and immune response

Helicobacter pylori (H. pylori) is one of the globally recognized causative factors of gastric cancer (GC). Currently, no definite therapy and drugs for H. pylori-related GC have been widely acknowledged although H. pylori infection could be eradicated in early stage. Inflammation and immune response are spontaneous essential stages during H. pylori infection. H pylori may mediate immune escape by affecting inflammation and immune response, leading to gastric carcinogenesis. As an important component of transcriptome, non-coding RNAs (ncRNAs) have been proven to play crucial roles in the genesis and development of H. pylori-induced GC. This review briefly described the effects of ncRNAs on H. pylori-related GC from the perspective of inflammation and immune response, as well as their association with inflammatory reaction and immune microenvironment. We aim to explore the potential of ncRNAs as markers for the early diagnosis, prognosis, and treatment of H. pylori-related GC. The ncRNAs involved in H. pylori-related GC may all hold promise as novel therapeutic targets for immunotherapy.

miR-223: An Immune Regulator in Infectious Disorders

MicroRNAs (miRNAs) are diminutive noncoding RNAs that can influence disease development and progression by post-transcriptionally regulating gene expression. The anti-inflammatory miRNA, miR-223, was first identified as a regulator of myelopoietic differentiation in 2003. This miR-223 exhibits multiple regulatory functions in the immune response, and abnormal expression of miR-223 is shown to be associated with multiple infectious diseases, including viral hepatitis, human immunodeficiency virus type 1 (HIV-1), and tuberculosis (TB) by influencing neutrophil infiltration, macrophage function, dendritic cell (DC) maturation and inflammasome activation. This review summarizes the current understanding of miR-223 physiopathology and highlights the molecular mechanism by which miR-223 regulates immune responses to infectious diseases and how it may be targeted for diagnosis and treatment.

Non-Coding RNAs in Gastric Cancer: From Malignant Hallmarks to Clinical Applications

Gastric cancer (GC) is one of the most lethal malignancies worldwide. However, the molecular mechanisms underlying gastric carcinogenesis remain largely unknown. Over the past decades, advances in RNA-sequencing techniques have greatly facilitated the identification of various non-coding RNAs (ncRNAs) in cancer cells, including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs). Accumulating evidence has revealed that ncRNAs are essential regulators in GC occurrence and development. However, ncRNAs represent an emerging field of cancer research, and their complex functionality remains to be clarified. Considering the lack of viable biomarkers and therapeutic targets in GC, further studies should focus on elucidating the intricate relationships between ncRNAs and GC, which can be translated into clinical practice. In this review, we summarize recent research progress on how ncRNAs modulate the malignant hallmarks of GC, especially in tumor immune escape, drug resistance, and stemness. We also discuss the promising applications of ncRNAs as diagnostic biomarkers and therapeutic targets in GC, aiming to validate their practical value for clinical treatment.

Prediction of Blood miRNA-mRNA Regulatory Network in Gastric Cancer

Background

The aim of the study was to suggest a high specific and sensitive blood biomarker for early GC diagnosis.

Methods

the expression data of miRNAs and mRNAs were collected from the blood samples of the GC patients based on literature mining. Bioinformatics tools and databases (PANTHER, TargetScan, miRTarBase, miRDB, STRING, and Cytoscape) were used to predict the regulatory relationship. Subsequently, expression level of the selected miRNA was evaluated in the blood samples of gastritis patients to recognize the common miRNA between the GC and gastritis patients.

Results

Analysis of 40 target genes by MCODE (installed in Cytoscape software) indicated 4 hub genes (WWP1, SKP2, KLHL42, and FBXO11) as a significant cluster in the PPI network related to miR-21, with Node Score Cutoff: 0.2, Degree Cutoff: 2 and K-Core: 2. In addition, the miRNA RT-qPCR results showed that, the expression level of miR-21 was significantly higher in gastritis group compared to the healthy group (p< 0.05).

Conclusion

the present study clearly demonstrated the increasing level of blood miR-21 among the gastritis patients infected by H. pylori. Therefore, the altered miRNAs, especially overexpression of onco-miRs, may identify a potential link between miRNAs and pathogenesis of the H. pylori-related complications.

Gastric Microenvironment-A Partnership between Innate Immunity and Gastric Microbiota Tricks Helicobacter pylori

Helicobacter pylori (H. pylori) carcinogenicity depends on three major factors: bacterial virulence constituents, environmental factors and host's genetic susceptibility. The relationship between microenvironmental factors and H. pylori virulence factors are incontestable. H. pylori infection has a major impact on both gastric and colonic microbiota. The presence of non-H. pylori bacteria within the gastric ecosystem is particularly important since they might persistently act as an antigenic stimulus or establish a partnership with H. pylori in order to augment the subsequent inflammatory responses. The gastric ecosystem, i.e., microbiota composition in children with H. pylori infection is dominated by Streptoccocus, Neisseria, Rothia and Staphylococcus. The impairment of this ecosystem enhances growth and invasion of different pathogenic bacteria, further impairing the balance between the immune system and mucosal barrier. Moreover, altered microbiota due to H. pylori infection is involved in increasing the gastric T regulatory cells response in children. Since gastric homeostasis is defined by the partnership between commensal bacteria and host's immune system, this review is focused on how pathogen recognition through toll-like receptors (TLRs-an essential class of pathogen recognition receptors-PRRs) on the surface of macrophages and dendritic cells impact the immune response in the setting of H. pylori infection. Further studies are required for delineate precise role of bacterial community features and of immune system components.

Comparative serum microRNA array analysis of the spleen-stomach dampness-heat syndrome in different diseases: Chronic hepatitis B and chronic gastritis

Spleen-stomach dampness-heat syndrome (SSDHS) is the common Traditional Chinese Medicine (TCM) syndrome observed in both chronic hepatitis B (CHB) and chronic gastritis (CG). The specialized TCM prescription for CHB and CG patients with SSDHS is same, but there is limited information about the biological characteristics of this TCM syndrome. This study aimed to identify the serum miRNAs profile for the SSDHS in two different diseases in order to evaluate the miRNA-mediated biological characteristics of this TCM syndrome. We performed comparative microarray analysis of serum miRNA expression profiles in 10 CHB patients with SSDHS (SSDHS-CHB), 10 CG patients with SSDHS (SSDHS-CG), and 10 healthy controls (HC). The selected miRNAs were further validated by qRT-PCR in 13 SSDHS-CHB patients, 13 SSDHS-CG patients, and 13 HC. Moreover, bioinformatics analysis (GO and KEGG pathway enrichment analyses) was applied to identify the involved target genes and pathways for these selected miRNAs. Nine significantly differentially expressed (SDE)-miRNAs in the SSDHS-CHB group and 24 SDE-miRNAs in the SSDHS-CG group were identified, compared with the HC group (fold change >2.0 and p < .05). Among these, upregulated hsa-miR-483-3p and downregulated hsa-miR-223-3p were identified as the common SDE-miRNAs for both SSDHS-CHB and SSDHS-CG groups. Bioinformatics analysis of the common SDE-miRNA's target genes showed their involvement in the regulation of inflammation, immune response, and tumorigenesis. SSDHS-specific hsa-miR-483-3p and hsa-miR-223-3p identified in this study indicated a relevance to the underlying biological basis of SSDHS, and may provide scientific basis for the application of same TCM prescription in CHB and CG.

Dysregulation of lncRNA in Helicobacter pylori-Infected Gastric Cancer Cells

Helicobacter pylori (H. pylori) infection is the most common cause of gastric cancer (GC). This microorganism is genetically diverse; GC is caused by several genetic deregulations in addition to environmental factors and bacterial virulence factors. lncRNAs (long noncoding RNAs) are significant biological macromolecules in GC, have specific functions in diseases, and could be therapeutic targets. Altered lncRNAs can lead to the abnormal expression of adjacent protein-coding genes, which may be important in cancer development. Their mechanisms have not been well understood, so we are going to investigate the risk of GC in a population with both high lncRNA and H. pylori infection.

Expression Profile of miRNA-17-3p and miRNA-17-5p Genes in Gastric Cancer Patients with Helicobacter pylori Infection

BACKGROUND

The most common chronic bacterial infection is Helicobacter pylori. The connection between chronic H. pylori infection and gastric cancer is recognized. The early detection of gastric cancer improves survival. miRNAs regulate gene expression in eukaryotes by inhibiting mRNA translocation or degradation. The objective of this study was to compare the expression of miRNA-17-3p and miRNA-17-5p genes in gastric cancer patients with Helicobacter pylori infection.

METHODS

Herein, 30 isolates were identified as H. pylori based on urease test, and 30 and 12 cases were isolated from gastric cancer patients and non-Helicobacter pylori cases as control, respectively. A peripheral blood sample was collected from patients. Analysis of total mRNA extracts from peripheral blood samples, for gene expression changes (miRNA-17-3p and miRNA-17-5p) by quantitative real-time polymerase chain reaction (qRT-PCR), was done.

RESULTS

As said by the results, p values showed that expression levels of miRNA-17-3p and miRNA-17-5p were significantly higher in H. pylori-positive GC patients and H. pylori-positive non-GC patients with comparing by healthy controls. So, there was no significant difference between expression levels of miRNA-17-3p and miRNA-17-5p in H. pylori-positive GC patients and H. pylori-positive non-GC patients.

CONCLUSION

Considering our results, the high expression of miRNA-17-3p and miRNA-17-5p has a direct relationship with increased cell proliferation, inhibition of tumor cell apoptosis and tumor angiogenesis, in addition to miRNAs play an important role as biomarkers in helping for detection of the patient by H. pylori infection to become cancerous. Therefore, it can be used to make specific diagnostic kits and to treat patients.

Cascades between miRNAs, lncRNAs and the NF-κB signaling pathway in gastric cancer (Review)

Gastric cancer is a common digestive tract malignancy that is mainly treated with surgery combined with perioperative adjuvant chemoradiotherapy and biological targeted therapy. However, the diagnosis rate of early gastric cancer is low and both postoperative recurrence and distant metastasis are thorny problems. Therefore, it is essential to study the pathogenesis of gastric cancer and search for more effective means of treatment. The nuclear factor-κB (NF-κB) signaling pathway has an important role in the occurrence and development of gastric cancer and recent studies have revealed that microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are able to regulate this pathway through a variety of mechanisms. Understanding these interrelated molecular mechanisms is helpful in guiding improvements in gastric cancer treatment. In the present review, the functional associations between miRNAs, lncRNAs and the NF-κB signaling pathway in the occurrence, development and prognosis of gastric cancer were discussed. It was concluded that miRNAs and lncRNAs have complex relations with the NF-κB signaling pathway in gastric cancer. miRNAs/target genes/NF-κB/target proteins, signaling molecules/NF-κB/miRNAs/target genes, lncRNAs/miRNAs/NF-κB/genes or mRNAs, lncRNAs/target genes/NF-Κb/target proteins, and lncRNAs/NF-κB/target proteins cascades are all important factors in the occurrence and development of gastric cancer.

Overexpression of microRNA-340-5p Ameliorates Inflammatory Response and Intracellular Survival of Mycobacterium Tuberculosis in Alveolar Type II Cells

Background

The importance of microRNAs (miRs) has been documented in infections. This study estimated the role of miR-340-5p in Mycobacterium tuberculosis (Mtb)-infected alveolar type II cells.

Methods

The microarray of GEO database was analyzed to find the differentially expressed miRs caused by Mtb infection, and miR-340-5p was selected as the research object. The effects of Mtb infection on A549 cells were studied by MTT, CFU, EdU, flow cytometry and ELISA assays. miR-340-5p expression was altered in Mtb-infected A549 cells. The downstream target of miR-340-5p was found by bioinformatics analysis and verified by the rescue experiment. The pathways regulated by miR-340-5p and its target gene were further studied.

Results

Mtb infection suppressed the activity of A549 cells and promoted the release of inflammatory factors. Mtb infection inhibited miR-340-5p expression. Overexpression of miR-340-5p enhanced the resistance of A549 cells to Mtb infection. Moreover, miR-340-5p targeted TMED7. Overexpression of TMED7 reversed the protective effect of miR-340-5p on Mtb-infected A549 cells. miR-340-5p inhibited the activation of NF-κB by targeting TMED7.

Conclusion

miR-340-5p inhibits the activation of NF-κB by targeting TMED7, thus alleviating the injury of A549 cells caused by Mtb infection. This study may offer a novel approach to Mtb infection.

MicroRNA Changes in Gastric Carcinogenesis: Differential Dysregulation during Helicobacter pylori and EBV Infection

Despite medical advances, gastric-cancer (GC) mortality remains high in Europe. Bacterial infection with Helicobacter pylori (H. pylori) and viral infection with the Epstein–Barr virus (EBV) are associated with the development of both distal and proximal gastric cancer. Therefore, the detection of these infections and the prediction of further cancer development could be clinically significant. To this end, microRNAs (miRNAs) could serve as promising new tools. MiRNAs are highly conserved noncoding RNAs that play an important role in gene silencing, mainly acting via translational repression and the degradation of mRNA targets. Recent reports demonstrate the downregulation of numerous miRNAs in GC, especially miR-22, miR-145, miR-206, miR-375, and miR-490, and these changes seem to promote cancer-cell invasion and tumor spreading. The dysregulation of miR-106b, miR-146a, miR-155, and the Let-7b/c complex seems to be of particular importance during H. pylori infection or gastric carcinogenesis. In contrast, many reports describe changes in host miRNA expression and outline the effects of bamHI-A region rightward transcript (BART) miRNA in EBV-infected tissue. The differential regulation of these miRNA, acting alone or in close interaction when both infections coexist, may therefore enable us to detect cancer earlier. In this review, we focus on the two different etiologies of gastric cancer and outline the molecular pathways through which H. pylori- or EBV-induced changes might synergistically act via miR-155 dysregulation to potentiate cancer risk. The three markers, namely, H. pylori presence, EBV infection, and miR-155 expression, may be checked in routine biopsies to evaluate the risk of developing gastric cancer.

Inflammatory microRNAs in gastric mucosa are modulated by Helicobacter pylori infection and proton-pump inhibitors but not by aspirin or NSAIDs

Gastric carcinogenesis is associated with alterations of microRNAs (miRNAs) and reversal of these alterations may be a crucial element in cancer prevention. Here we evaluate the influence of H. pylori eradication, low-dose aspirin (LDA), non-steroidal anti-inflammatory drugs (NSAIDs) and proton-pump inhibitors (PPI) on modification of inflammatory mucosal miRNAs miR-155 and miR-223 in Helicobacter pylori-infected and non-infected subjects. The study was performed in two parts: 1) interventional study in 20 healthy subjects with and without H. pylori infection or following eradication (each n = 10) where LDA (100 mg) was given daily for 7 days; 2) prospective case-control observational study (n = 188). MiR-155 and miR-223 expression was strongly linked to H. pylori-infection and in short-term view showed a trend for reversal after eradication. Daily LDA as well as regular NSAIDs showed no influence on miRNAs expression both in healthy subjects and patients, while regular PPI intake was associated with lower miR-155 expression in antrum of patients with chronic gastritis independent of density of neutrophils and mononuclear infiltrate. In summary, PPI but not LDA or NSAIDs were associated with modification of inflammatory miRNAs miR-155 and miR-223 in an H. pylori dependent manner. The functional role of inflammatory miR-155 and miR-223 in understanding of H. pylori-related diseases needs further evaluation.

Highly Sensitive and Specific Mass Spectrometric Platform for miRNA Detection Based on the Multiple-Metal-Nanoparticle Tagging Strategy

The multiple-metal-nanoparticle tagging strategy has generally been applied to the multiplexed detection of multiple analytes of interest such as microRNAs (miRNAs). Herein, it was used for the first time to improve both the specificity and sensitivity of a novel mass spectroscopic platform for miRNA detection. The mass spectroscopic platform was developed through the integration of the ligation reaction, hybridization chain reaction amplification, multiple-metal-nanoparticle tagging, and inductively coupled plasma mass spectrometry. The high specificity resulted from the adoption of the ligation reaction is further enhanced by the multiple-metal-nanoparticle tagging strategy. The combination of hybridization chain reaction amplification and metal nanoparticle tagging endows the proposed platform with the feature of high sensitivity. The proposed mass spectrometric platform achieved quite satisfactory quantitative results for Let-7a in real-world cell line samples with accuracy comparable to that of the real-time quantitative reverse-transcriptase polymerase chain reaction method. Its limit of detection and limit of quantification for Let-7a were experimentally determined to be about 0.5 and 10 fM, respectively. Furthermore, due to the unique way of utilizing the multiple-metal-nanoparticle tagging strategy, the proposed platform can unambiguously discriminate between the target miRNA and nontarget ones with single-nucleotide polymorphisms based on their response patterns defined by the relative mass spectral intensities among the multiple tagged metal elements and can also provide location information of the mismatched bases. Its unique advantages over conventional miRNA detection methods make the proposed platform a promising and alternative tool in the fields of clinical diagnosis and biomedical research.

Distinct Age-Specific miRegulome Profiling of Isolated Small and Large Intestinal Epithelial Cells in Mice

The intestinal epithelium serves as a dynamic barrier to protect the host tissue from exposure to a myriad of inflammatory stimuli in the luminal environment. Intestinal epithelial cells (IECs) encompass differentiated and specialized cell types that are equipped with regulatory genes, which allow for sensing of the luminal environment. Potential inflammatory cues can instruct IECs to undergo a diverse set of phenotypic alterations. Aging is a primary risk factor for a variety of diseases; it is now well-documented that aging itself reduces the barrier function and turnover of the intestinal epithelium, resulting in pathogen translocation and immune priming with increased systemic inflammation. In this study, we aimed to provide an effective epigenetic and regulatory outlook that examines age-associated alterations in the intestines through the profiling of microRNAs (miRNAs) on isolated mouse IECs. Our microarray analysis revealed that with aging, there is dysregulation of distinct clusters of miRNAs that was present to a greater degree in small IECs (22 miRNAs) compared to large IECs (three miRNAs). Further, miRNA-mRNA interaction network and pathway analyses indicated that aging differentially regulates key pathways between small IECs (e.g., toll-like receptor-related cascades) and large IECs (e.g., cell cycle, Notch signaling and small ubiquitin-related modifier pathway). Taken together, current findings suggest novel gene regulation pathways by epithelial miRNAs in aging within the gastrointestinal tissues.

MicroRNAs in the interaction between host-bacterial pathogens: A new perspective

Gene expression regulation plays a critical role in host-pathogen interactions, and RNAs function is essential in this process. miRNAs are small noncoding, endogenous RNA fragments that affect stability and/or translation of mRNAs, act as major posttranscriptional regulators of gene expression. miRNA is involved in regulating many biological or pathological processes through targeting specific mRNAs, including development, differentiation, apoptosis, cell cycle, cytoskeleton organization, and autophagy. Deregulated microRNA expression is associated with many types of diseases, including cancers, immune disturbances, and infection. miRNAs are a vital section of the host immune response to bacterial-made infection. Bacterial pathogens suppress host miRNA expression for their benefit, promoting survival, replication, and persistence. The role played through miRNAs in interaction with host-bacterial pathogen has been extensively studied in the past 10 years, and knowledge about these staggering molecules' function can clarify the complicated and ambiguous interactions of the host-bacterial pathogen. Here, we review how pathogens prevent the host miRNA expression. We briefly discuss emerging themes in this field, including their role as biomarkers in identifying bacterial infections, as part of the gut microbiota, on host miRNA expression.

MicroRNA Modulation of Host Immune Response and Inflammation Triggered by Helicobacter pylori

Helicobacter pylori (H. pylori) remains the most-researched etiological factor for gastric inflammation and malignancies. Its evolution towards gastric complications is dependent upon host immune response. Toll-like receptors (TLRs) recognize surface and molecular patterns of the bacterium, especially the lipopolysaccharide (LPS), and act upon pathways, which will finally lead to activation of the nuclear factor-kappa B (NF-kB), a transcription factor that stimulates release of inflammatory cytokines. MicroRNAs (MiRNAs) finely modulate TLR signaling, but their expression is also modulated by activation of NF-kB-dependent pathways. This review aims to focus upon several of the most researched miRNAs on this subject, with known implications in host immune responses caused by H. pylori, including let-7 family, miRNA-155, miRNA-146, miRNA-125, miRNA-21, and miRNA-221. TLR-LPS interactions and their afferent pathways are regulated by these miRNAs, which can be considered as a bridge, which connects gastric inflammation to pre-neoplastic and malignant lesions. Therefore, they could serve as potential non-invasive biomarkers, capable of discriminating H. pylori infection, as well as its associated complications. Given that data on this matter is limited in children, as well as for as significant number of miRNAs, future research has yet to clarify the exact involvement of these entities in the progression of H. pylori-associated gastric conditions.

Extracellular miRNAs for the Management of Barrett's Esophagus and Esophageal Adenocarcinoma: A Systematic Review

Esophageal adenocarcinoma (EAC), the major histologic type of esophageal cancer (EC) in Western countries, is a disease with a poor prognosis, primarily due to usual diagnosis at an advanced stage. The prevalence of EAC has increased in recent years, both in Western countries and in Asia. Barrett's esophagus (BE) is a precursor lesion of EAC. Therefore, early detection and proper management of BE and EAC is important to improve prognosis. Here, we systematically summarize current knowledge about the potential utility of extracellular microRNAs (miRNAs), which are thought to be non-invasive biomarkers for many diseases, for these purposes. A search of the PubMed and Embase databases identified 22 papers about extracellular miRNAs that have potential utility for management of EAC. Among them, 19 were EAC-related and ten were BE-related; some of these dealt with both conditions. The articles included studies reporting diagnosis, prognosis, and treatment responses. Multiple papers report dysregulation of miR-194-5p in BE and miR-21-5p, -25-3p, and -93-5p in EAC. Although it will take time to utilize these miRNAs in clinical practice, they are likely to be useful non-invasive markers in the future.

Epigenetic silencing of microRNA-204 by Helicobacter pylori augments the NF-κB signaling pathway in gastric cancer development and progression

Helicobacter pylori infection induces gastric cancer (GC) development through a progressive cascade; however, the roles of the microRNAs that are involved in the cascade and the underlying mechanisms are still unclear. Here, we found that microRNA-204 was suppressed in gastric mucosal cells in response to H.pylori infection and downregulated in GC tissues due to aberrant methylation of the promoter of its host gene, TRPM3. Helicobacter pylori induced a progressive downregulation of microRNA-204 from superficial gastritis to intestinal metaplasia, with an accompanying increment of the methylated levels of CpG sites in the TRPM3 promoter. With the GC cellular models of AGS, MGC-803 or BGC-823, we found that microRNA-204 suppressed the tumor necrosis factor (TNF)-α-induced activation of NF-κB signaling pathways and, in animal models, inhibited tumor growth and metastasis. The conditional supernatant of microRNA-204 overexpression GC cells led to reduced tube formation of human umbilical vein endothelial cells. A target gene for microRNA-204 was BIRC2, and in GC cells, BIRC2 knockdown recapitulated the biological phenotype of microRNA-204 overexpression. BIRC2 overexpression promoted the metastasis of GC cells and rescued the inhibition activities of microRNA-204 on cell migration and the NF-κB signaling pathway. Moreover, lower microRNA-204 and higher BIRC2 expression levels were associated with a poorer prognosis of GC patients. These results demonstrate that epigenetic silencing of microRNA-204 induced by H.pylori infection augments the NF-κB signaling pathway in H.pylori-induced gastritis and GC, potentially providing novel intervention targets for these diseases. MicroRNA-204 was epigenetically down-regulated by H. pylori infection in gastric mucosal cells. It led to enhanced BIRC2 expression level and BIRC2/TNF-a/NF-kB signaling pathway activities, which promoted angiogenesis and metastasis of gastric cancer cells.

Evaluation of miR-21 Expression Level in Helicobacter pylori-Infected Gastric Mucosa

Background: Gastric cancer is one of the main causes of death worldwide. In this regard, Helicobacter pylori infection is considered as the main risk factor for gastric cancer. MicroRNA (mirNA) can interface with mRNA molecules as well as blocking their translation into proteins or inducing degradation. Objectives: The aim of this study was to compare the expression of mir-21 in biopsy samples of gastritis and healthy adjacent tissues. Methods: Between Feb-Dec 2017, 70 patients with dyspeptic symptoms from Taleghani Hospital were enrolled in this study. Accordingly, the expression level of mir-21 was evaluated using semi-quantitative RT-PCR in mucosal biopsy samples from those well-characterized patients. Moreover, the U6 gene was used as an internal control. Results: Our data indicated that mir-21 expression was significantly up-regulated in the infected samples with H. pylori compared to healthy samples. Conclusions: Our results confirm that H. pylori infection can alter the expression of mir-21 in gastric epithelial cells and gastric mucosal tissues. However, the exact role of the miRNA changes in H. pylori infection will require further experiments.

Potential Associations Among Alteration of Salivary miRNAs, Saliva Microbiome Structure, and Cognitive Impairments in Autistic Children

Recent evidence has demonstrated that salivary molecules, as well as bacterial populations, can be perturbed by several pathological conditions, including neuro-psychiatric diseases. This relationship between brain functionality and saliva composition could be exploited to unveil new pathological mechanisms of elusive diseases, such as Autistic Spectrum Disorder (ASD). We performed a combined approach of miRNA expression profiling by NanoString technology, followed by validation experiments in qPCR, and 16S rRNA microbiome analysis on saliva from 53 ASD and 27 neurologically unaffected control (NUC) children. MiR-29a-3p and miR-141-3p were upregulated, while miR-16-5p, let-7b-5p, and miR-451a were downregulated in ASD compared to NUCs. Microbiome analysis on the same subjects revealed that Rothia, Filifactor, Actinobacillus, Weeksellaceae, Ralstonia, Pasteurellaceae, and Aggregatibacter increased their abundance in ASD patients, while Tannerella, Moryella and TM7-3 decreased. Variations of both miRNAs and microbes were statistically associated to different neuropsychological scores related to anomalies in social interaction and communication. Among miRNA/bacteria associations, the most relevant was the negative correlation between salivary miR-141-3p expression and Tannerella abundance. MiRNA and microbiome dysregulations found in the saliva of ASD children are potentially associated with cognitive impairments of the subjects. Furthermore, a potential cross-talking between circulating miRNAs and resident bacteria could occur in saliva of ASD.

Mycoplasma hyopneumoniae J elicits an antioxidant response and decreases the expression of ciliary genes in infected swine epithelial cells

Mycoplasma hyopneumoniae is the most costly pathogen for swine production. Although several studies have focused on the host-bacterium association, little is known about the changes in gene expression of swine cells upon infection. To improve our understanding of this interaction, we infected swine epithelial NPTr cells with M. hyopneumoniae strain J to identify differentially expressed mRNAs and miRNAs. The levels of 1,268 genes and 170 miRNAs were significantly modified post-infection. Up-regulated mRNAs were enriched in genes related to redox homeostasis and antioxidant defense, known to be regulated by the transcription factor NRF2 in related species. Down-regulated mRNAs were enriched in genes associated with cytoskeleton and ciliary functions. Bioinformatic analyses suggested a correlation between changes in miRNA and mRNA levels, since we detected down-regulation of miRNAs predicted to target antioxidant genes and up-regulation of miRNAs targeting ciliary and cytoskeleton genes. Interestingly, most down-regulated miRNAs were detected in exosome-like vesicles suggesting that M. hyopneumoniae infection induced a modification of the composition of NPTr-released vesicles. Taken together, our data indicate that M. hyopneumoniae elicits an antioxidant response induced by NRF2 in infected cells. In addition, we propose that ciliostasis caused by this pathogen is partially explained by the down-regulation of ciliary genes.

Construction and Investigation of MicroRNA-mRNA Regulatory Network of Gastric Cancer with Helicobacter pylori Infection

Background

Helicobacter pylori (H. pylori) is a common human pathogen, which is closely correlated with gastric cancer (GC). However, the mechanism of H. pylori-related GC has not been elucidated. This study aimed to explore the role of H. pylori infection in GC and find biomarkers for early diagnosis of H. pylori-related GC.

Methods

We identified differentially expressed microRNAs (DEMs) and genes (DEGs) from the Gene Expression Omnibus (GEO) dataset, constructed microRNA-(miRNA-)mRNA expression networks, analyzed the function and signal pathway of cross-genes, analyzed the relations between cross-genes and GC prognosis with the Cancer Genome Atlas (TCGA) data, and verified the expression of cross-genes in patients with H. pylori infection.

Results

22 DEMs and 68 DEGs were identified in GSE197694 and GSE27411 dataset. 16 miRNAs and 509 genes were involved in the expression network, while the cross-genes of the network were mainly enriched in MAP kinase (MAPK) signaling pathway and TGF-beta signaling pathway. Patients with higher expression of hsa-miR-196b-3p, CALML4, or SMAD6 or lower expression of PITX2 or TGFB2 had better outcomes than those with lower expression of hsa-miR-196b-3p, CALML4, or SMAD6 or higher expression of PITX2 or TGFB2 (P < 0.05). Patients with H. pylori infection had a higher expression of hsa-miR-196b-3p and CALML4 than those without H. pylori infection (P < 0.05).

Conclusion

The study of miRNA-mRNA expression network would provide molecular support for early diagnosis and treatment of H. pylori-related GC.

Fluctuating expression of miR-584 in primary and high-grade gastric cancer

Background

Gastric cancer is the fifth most common cancer worldwide. Along with environmental factors, such as Helicobacter pylori (H. pylori) infection, genetic changes play important roles in gastric tumor formations. miR-584 is a less well-characterized microRNA (miRNA), with apparent activity in human cancers. However, miR-584 expression pattern in gastric cancer development has remained unclear. This study aims to analyze the expression of miR-584 in gastric cancer samples and investigates the associations between this miRNA and H. pylori infection and clinical characteristics.

Methods

The expression level of miR-584 was studied in primary gastric cancers versus healthy control gastric mucosa samples using the RT-qPCR method. The clinical data were analyzed statistically in terms of miR-584 expression. In silico studies were employed to study miR-584 more broadly in order to assess its expression and find new potential target genes.

Results

Both experimental and in silico studies showed up-regulation of miR-584 in patients with gastric cancer. This up-regulation seems to be induced by H. pylori infection since the infected samples showed increased levels of miR-584 expression. Deeper analyses revealed that miR-584 undergoes a dramatic down-regulation in late stages, invasive and lymph node-metastatic gastric tumors. Bioinformatics studies demonstrated that miR-584 has a substantial role in cancer pathways and has the potential to target STAT1 transcripts. Consistent with the inverse correlation between TCGA RNA-seq data of miR-584 and STAT1 transcripts, the qPCR analysis showed a significant negative correlation between these two RNAs in a set of clinical samples.

Conclusion

miR-584 undergoes up-regulation in the stage of primary tumor formation; however, becomes down-regulated upon the progression of gastric cancer. These findings suggest the potential of miR-584 as a diagnostic or prognostic biomarker in gastric cancer.

Dysregulated Expression of Apoptosis-Associated Genes and MicroRNAs and Their Involvement in Gastric Carcinogenesis

PURPOSE

Analyze the expression of caspase-9, Smac/DIABLO, XIAP, let-7a, and let-7b in patients with normal gastric tissue, chronic gastritis, and gastric adenocarcinoma.

METHODS

The expression of caspase-9, Smac/DIABLO, XIAP, let-7a, and let-7b by qRT-PCR was analyzed in 158 samples from 53 patients with normal gastric mucosa, 86 with chronic gastritis, and 19 with gastric cancer.

RESULTS

The comparison between the gastric cancer and the control group revealed a decreased expression of caspase-9 in gastric cancer tissues; considering the Helicobacter pylor presence, comparable results were revealed. Smac/DIABLO was increased in gastric cancer cells, while XIAP demonstrated no significant difference in the gene expression. The microRNA analysis revealed a decreased expression of let-7a and let-7b in samples positive to H. pylori infection and in gastric cancer group, regardless of the presence of the bacterium.

CONCLUSION

Our study provided some evidence of low activity of the intrinsic apoptosis pathway, as well as the influence of H. pylori on let-7a and let-7b expression.

Immune-Inflammation in Atherosclerosis: A New Twist in an Old Tale

Background and Objective:

Atherosclerosis, a chronic and progressive inflammatory disease, is triggered by the activation of endothelial cells followed by infiltration of innate and adaptive immune cells including monocytes and T cells in arterial walls. Major populations of T cells found in human atherosclerotic lesions are antigen-specific activated CD4+ effectors and/or memory T cells from Th1, Th17, Th2 and Treg subsets. In this review, we will discuss the significance of T cell orchestrated immune inflammation in the development and progression of atherosclerosis.

Discussion:

Pathogen/oxidative stress/lipid induced primary endothelial wound cannot develop to a full-blown atherosclerotic lesion in the absence of chronically induced inflammation. While the primary inflammatory response might be viewed as a lone innate response, the persistence of such a profound response over time must be (and is) associated with diverse local and systemic T cell responses. The interplay between T cells and innate cells contributes to a phenomenon called immuneinflammation and has an impact on the progression and outcome of the lesion. In recent years immuneinflammation, an old term, has had a comeback in connecting the puzzle pieces of chronic inflammatory diseases.

Conclusion:

Taking one-step back and looking from afar at the players of immune-inflammation may help us provide a broader perspective of these complicated interactions. This may lead to the identification of new drug targets and the development of new therapies as well as preventative measures.

Comprehensive analysis of Helicobacter pylori infection-associated diseases based on miRNA-mRNA interaction network

Helicobacter pylori (H. pylori) infection remains a cause of significant morbidity and mortality worldwide. Comprehensive understanding of the pathogenic mechanism of H. pylori and its interaction with host will contribute to developing novel prophylactical and therapeutical strategies. Here, we first determined microRNA (miRNA) levels in H. pylori-infected patients with gastritis, duodenal ulcer, gastric cancer or mucosa-associated lymphoid tissue lymphoma using miRNA data sets. Thirty-four differentially expressed miRNAs were identified and functional enrichment analysis of those miRNA target genes revealed that H. pylori infection were strongly associated with pathway in cancer and regulation of mRNA synthesis. Using disease connectivity analysis of 28 hub genes, we found that H. pylori may increase the risk of many extragastric diseases (e.g. cardiovascular disease, hemic and lymphatic diseases and nervous system disease). Altogether, our integrated analysis provided a new method to predict pathogen–human disease connectivity based on miRNA-mRNA interaction network and indicated anti-H. pylori therapy as an effective means of human diseases prevention.

MicroRNA (miR) dysregulation during Helicobacter pylori-induced gastric inflammation and cancer development: critical importance of miR-155

Dysregulation of noncoding microRNA molecules has been associated with immune cell activation in the context of Helicobacter pylori induced gastric inflammation as well as carcinogenesis, but also with downregulation of mismatch repair genes, and may interfere with immune checkpoint proteins that lead to the overexpression of antigens on gastric tumor cells. Numerous miR-molecules have been described as important tools and markers in gastric inflammation and cancer development -including miR-21, miR-143, miR-145, miR-201, and miR-335- all of which are downregulated in gastric tumors, and involved in cell cycle growth or tumor invasion. Among the many microRNAs involved in gastric inflammation, adenocarcinoma development and immune checkpoint regulation, miR-155 is notable in that its upregulation is considered a key marker of chronic gastric inflammation that predisposes a patient to gastric carcinogenesis. Among various other miRs, miR-155 is highly expressed in activated B and T cells and in monocytes/macrophages present in chronic gastric inflammation. Notably, miR-155 was shown to downregulate the expression of certain MMR genes, such as MLH1, MSH2, and MSH6. In tumor-infiltrating miR-155-deficient CD8⁺ T cells, antibodies against immune checkpoint proteins restored the expression of several derepressed miR-155 targets, suggesting that miR-155 may regulate overlapping pathways to promote antitumor immunity. It may thus be of high clinical impact that gastric pathologies mediated by miR-155 result from its overexpression. This suggests that it may be possible to therapeutically attenuate miR-155 levels for gastric cancer treatment and/or to prevent the progression of chronic gastric inflammation into cancer.

Transcriptome hallmarks in Helicobacter pylori infection influence gastric cancer and MALT lymphoma

Aim: Altered long noncoding RNA (lncRNA) and mRNA is vital in the progression from Helicobacter pylori (H. pylori, HP) infection to gastric cancer (GC) and mucosa-associated lymphoid tissue (MALT) lymphoma. Materials & methods: Five independent Gene Expression Omnibus datasets (GSE5081, GSE84433, GSE15459, GSE66229 and GSE25638) were included in our study. Results: Differentially expressed lncRNAs and mRNAs in both H. pylori-positive gastritis and GC tissues were identified. Using two GC cohorts, the H. pylori-related mRNA DYNC1I1 and MMP7 were independent predictors of overall survival. Moreover, the expressions of lncRNA GHRLOS and 44 mRNAs were significantly changed in gastric MALT lymphoma patients. Conclusion: The lncRNA/mRNA response to H. pylori infection in gastritis and GC influence the outcome of GC and progression of MALT lymphoma.

Emerging role of m6 A RNA methylation in nutritional physiology and metabolism

N6 -methyladenine (m6 A) is the most prevalent type of internal RNA methylation in eukaryotic mRNA and plays critical roles in regulating gene expression for fundamental cellular processes and diverse physiological functions. Recent evidence indicates that m6 A methylation regulates physiology and metabolism, and m6 A has been increasingly implicated in a variety of human diseases, including obesity, diabetes, metabolic syndrome and cancer. Conversely, nutrition and diet can modulate or reverse m6 A methylation patterns on gene expression. In this review, we summarize the recent progress in the study of the m6 A methylation mechanisms and highlight the crosstalk between m6 A modification, nutritional physiology and metabolism.

The Prognostic and Predictive Value of microRNAs in Patients with H. pylori-positive Gastric Cancer

Gastric cancer (GC) has a high mortality rate with a poor 5-year survival. Helicobacter pylori (H. pylori) is present as part of the normal flora of stomach. It is found in the gastric mucosa of more than half of the world population. This bacterium is involved in developing H. pylori-induced GC due to the regulation of different micro ribonucleic acid (miRNA or miR). miRNAs are small noncoding RNAs and are recognized as prognostic biomarkers for GC that may control gene expression. miRNAs may function as tumor suppressors, or oncogenes. In this review, we evaluated studies that investigated the ectopic expression of miRNAs in the prognosis of H. pylori positive and negative GC.

E-cadherin Downregulation and microRNAs in Sporadic Intestinal-Type Gastric Cancer

CDH1 gene, encoding E-cadherin, is a tumor suppressor gene frequently altered in gastric cancers (GCs) of both diffuse (DGC) and intestinal (IGC) histotypes, albeit through different mechanisms. The study aimed to characterize CDH1 expression in sporadic IGC and to investigate whether microRNAs (miRs) are involved in its transcriptional control. We evaluated CDH1 expression by quantitative real-time PCR (RT-qPCR) in 33 IGC patients and found a significant downregulation in tumor tissues compared to normal counterparts (p-value = 0.025). Moreover, 14 miRs, predicted to be involved in CDH1 regulation in both a direct and indirect manner, were selected and analyzed by RT-qPCR in an independent case series of 17 IGCs and matched normal tissues. miR-101, miR-26b, and miR-200c emerged as significantly downregulated and were confirmed in the case series of 33 patients (p-value < 0.001). Finally, we evaluated EZH2 expression, a target of both miR-101 and miR-26b, which showed significant upregulation in IGCs (p-value = 0.005). A significant inverse correlation was observed between EZH2 overexpression and CDH1, miR-101, and miR-26b levels (p-value < 0.001). Our results reinforce the link between CDH1 and IGC, highlighting the role of miRs in its transcriptional control and improving our understanding of GC subtypes and biomarkers.

Review: Helicobacter pylori in pediatrics

Despite a decrease in the prevalence of Helicobacter pylori infection, it still poses a significant health burden worldwide. This review summarizes important pediatric studies on H pylori published from April 2018 to March 2019. Epidemiologic studies have reported different prevalences in different parts of the world and have mainly confirmed traditional risk factors. Several studies on pathophysiology attempted to identify risk markers in childhood for gastric cancer development later in life. One of the most interesting studies evaluated the relationship between eosinophilic esophagitis and H pylori infection; however, an inverse relationship was not confirmed. The high resistance of H pylori and, consequently, low eradication rates, is still a major concern and susceptibility testing before treatment has again been highlighted. Potassium-competitive acid blockers are promising new acid-suppressant drugs but their role in H pylori eradication schemes is still to be determined.

Decrease in MiR-148a Expression During Initiation of Chief Cell Transdifferentiation

Gastric chief cells differentiate from mucous neck cells and develop their mature state at the base of oxyntic glands with expression of secretory zymogen granules. After parietal cell loss, chief cells transdifferentiate into mucous cell metaplasia, designated spasmolytic polypeptide-expressing metaplasia (SPEM), which is considered a candidate precursor of gastric cancer. We examined the range of microRNA (miRNA) expression in chief cells and identified miRNAs involved in chief cell transdifferentiation into SPEM. Among them, miR-148a was strongly and specifically expressed in chief cells and significantly decreased during the process of chief cell transdifferentiation. Interestingly, suppression of miR-148a in a conditionally immortalized chief cell line induced up-regulation of CD44 variant 9 (CD44v9), one of the transcripts expressed at an early stage of SPEM development, and DNA methyltransferase 1 (Dnmt1), an established target of miR-148a. Immunostaining analyses showed that Dnmt1 was up-regulated in SPEM cells as well as in chief cells before the emergence of SPEM in mouse models of acute oxyntic atrophy using either DMP-777 or L635. In the cascade of events that leads to transdifferentiation, miR-148a was down-regulated after acute oxyntic atrophy either in xCT knockout mice or after sulfasalazine inhibition of xCT. These findings suggest that the alteration of miR-148a expression is an early event in the process of chief cell transdifferentiation into SPEM.

Crosstalk Between DNA Damage and Inflammation in the Multiple Steps of Gastric Carcinogenesis

Over the last years, intensive investigations in molecular biology and cell physiology extended tremendously the knowledge about the association of inflammation and cancer. In frame of this paradigm, the human pathogen Helicobacter pylori triggers gastritis and gastric ulcer disease, and contributes to the development of gastric cancer. Mechanisms, by which the bacteria-induced inflammation in gastric mucosa leads to intestinal metaplasia and carcinoma, are represented in this review. An altered cell-signaling response and increased production of free radicals by epithelial and immune cells account for the accumulation of DNA damage in gastric mucosa, if infection stays untreated. Host genetics and environmental factors, especially diet, can accelerate the process, which offers the opportunity of intervention based on a balanced nutrition. It is supposed that inflammation might influence stem- or progenitor cells in gastric tissue predisposing for metaplasia or tumor relapse. Herein, DNA is strongly mutated and labile, which restricts therapy options. Thus, the understanding of the mechanisms that underlie gastric carcinogenesis will be of preeminent importance for the development of strategies for screening and early detection. As most gastric cancer patients face late-stage disease with a poor overall survival, the development of multi-targeted therapeutic intervention strategies is a major challenge for the future.

Regulation of GKN1 expression in gastric carcinogenesis: A problem to resolve (Review)

Gastrokine 1 (GKN1) is a protein expressed on the surface mucosa cells of the gastric antrum and fundus, which contributes to maintaining gastric homeostasis, inhibits inflammation and is a tumor suppressor. The expression of GKN1 decreases in mucosa that are either inflamed or infected by Helicobacter pylori, and is absent in gastric cancer. The measurement of circulating GKN1 concentration, the protein itself, or the mRNA in gastric tissue may be of use for the early diagnosis of cancer. The mechanisms that modulate the deregulation or silencing of GKN1 expression have not been completely described. The modification of histones, methylation of the GKN1 promoter, or proteasomal degradation of the protein have been detected in some patients; however, these mechanisms do not completely explain the absence of GKN1 or the reduction in GKN1 levels. Only NKX6.3 transcription factor has been shown to be a positive modulator of GKN1 transcription, although others also have an affinity with sequences in the promoter of this gene. While microRNAs (miRNAs) are able to directly or indirectly regulate the expression of genes at the post‑transcriptional level, the involvement of miRNAs in the regulation of GKN1 has not been reported. The present review analyzes the information reported on the determination of GKN1 expression and the regulation of its expression at the transcriptional, post‑transcriptional and post‑translational levels; it proposes an integrated model that incorporates the regulation of GKN1 expression via transcription factors and miRNAs in H. pylori infection.