Immunohistochemical Expressions of MUC2, MUC5AC, and MUC6 in Normal, Helicobacter pylori Infected and Metaplastic Gastric Mucosa of Children and Adolescents

Expression of MUC-2, MUC-6, NAPE-PLD, IL-6 and IL-13 in Healthy and Metaplastic Bronchial Epithelium

Background: The normal tissue structure of the respiratory system is necessary to provide adequate protection of the airways and lungs. Prolonged exposure to trigger factors can result in adaptive mechanism activation and lead to the development of chronic pulmonary diseases or even dysplastic changes. Materials and methods: Respiratory system material with a pseudostratified ciliated epithelium was obtained from 12 patients (aged 16 to 95), and material with a stratified squamosa epithelium was obtained from six patients (aged 23 to 93). Routine staining was performed, and an immunohistochemistry was conducted for MUC-2, MUC-6, NAPE-PLD, IL-6 and IL-13. Results: Inflammatory processes were not detected in any of the specimens. A number of correlations were identified, with the most important being a strong positive correlation for IL-13 between the alveolar epithelium and alveolar macrophages and a strong positive correlation for IL-6 between the alveolar epithelium and alveolar macrophages in the stratified squamous epithelium group. We also detected a statistically significant difference in IL-6 in alveolar macrophages. Conclusions: There were no signs of dysplastic changes in either group. Increased secretion of IL-13 in the stratified squamous epithelium group shows its involvement in metaplastic changes in the bronchial epithelium. The secretion of atypical factors by hyaline cartilage demonstrates its plasticity and adaptability.

Calponin and MUC6 complement inhibin as diagnostic immunomarkers of serous cystadenoma in endoscopic ultrasound-guided aspiration/biopsy specimens

AIMS

Because serous cystadenoma (SCA) does not usually require excision, it is critical to distinguish it from differential diagnoses which do, especially neuroendocrine tumour (NET). The gold standard for diagnosing SCA is assessment of endoscopic ultrasound-guided fine needle aspiration/biopsy (EUS-FNAB) material. Inhibin immunohistochemistry aids this assessment, but such positivity is not absolutely sensitive or specific to SCA. The following is the largest known study of SCA EUS-FNAB specimens and the first to compare four potential SCA immunomarkers between themselves and inhibin, compared against NET.

METHODS AND RESULTS

Immunohistochemistry for calponin, mucin 6 (MUC6), glucose transporter 1 (GLUT1) and vascular endothelial growth factor A (VEGFA) was performed on 30 EUS-FNAB and three resection specimens of SCA and 32 EUS-FNAB specimens of NET. GLUT1 and VEGFA were suboptimal as diagnostic immunomarkers of SCA, being expressed by 10 and 44% of NETs, respectively. Further, their expression by cellular constituents of blood which often contaminate EUS-FNAB specimens hampered identification of neoplastic cells, especially in hypocellular samples. While 19% of NETs showed nuclear MUC6 positivity, cytoplasmic expression of the protein showed 100% specificity and sensitivity as an SCA marker. However, assessing MUC6 in EUS-FNAB specimens must also consider the protein's focal expression in physiological pancreatic, gastric or duodenal tissues, which can contaminate these specimens. Calponin was less sensitive (71% versus 100%) but more specific (100% versus 91%) than inhibin, although easier to assess in EUS-FNAB specimens than MUC6.

CONCLUSIONS

Of the four potential immunomarkers of SCA suggested by the existing literature, calponin and MUC6 are useful complementary studies to inhibin for application to EUS-FNAB specimens.

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.

Helicobacter pylori Infection and the Patterns of Gastric Mucin Expression in Children

Background: The updated model for the mechanism of gastric carcinogenesis demonstrates that Helicobacter pylori (H. pylori) is a risk factor in every step of the process. The expression of certain gastric mucins is altered by H. pylori infection in adult patients. The aim of our research was to assess the impact of H. pylori infection on the expression of secretory mucins in the pediatric antral mucosa. Methods: Slides were stained with monoclonal antibodies for MUC5AC, MUC6 and MUC2, digitalized and scored using both a semiquantitative and a quantitative approach. Results: The expression of MUC5AC was significantly lower in infected children. Also, MUC2 expression was more pronounced in infected children. MUC6 expression did not differentiate between infected and noninfected children. Additionally, the presence of chronic inflammation significantly altered the expression of MUC6 and MUC2. The expression of MUC6 was significantly higher in patients with gastric atrophy. Conclusion: The minor differences in mucin expression at distinct ages might stem from different H. pylori exposure periods. Further research is needed to determine the particular patterns of expression according to age and to evaluate the effects of the interaction between H. pylori and mucins in the progression of the gastric carcinogenesis cascade.

Gastric Damage and Cancer-Associated Biomarkers in Helicobacter pylori-Infected Children

Helicobacter pylori (H. pylori) is well-known to be involved in gastric carcinogenesis, associated with deregulation of cell proliferation and epigenetic changes in cancer-related genes. H. pylori infection is largely acquired during childhood, persisting long-term in about half of infected individuals, a subset of whom will go on to develop peptic ulcer disease and eventually gastric cancer, however, the sequence of events leading to disease is not completely understood. Knowledge on carcinogenesis and gastric damage-related biomarkers is abundant in adult populations, but scarce in children. We performed an extensive literature review focusing on gastric cancer related biomarkers identified in adult populations, which have been detected in children infected with H. pylori. Biomarkers were related to expression levels (RNA or protein) and/or methylation levels (DNA) in gastric tissue or blood of infected children as compared to non-infected controls. In this review, we identified 37 biomarkers of which 24 are over expressed, three are under expressed, and ten genes are significantly hypermethylated in H. pylori-infected children compared to healthy controls in at least 1 study. Only four of these biomarkers (pepsinogen I, pepsinogen II, gastrin, and SLC5A8) have been studied in asymptomatically infected children. Importantly, 13 of these biomarkers (β-catenin, C-MYC, GATA-4, DAPK1, CXCL13, DC-SIGN, TIMP3, EGFR, GRIN2B, PIM2, SLC5A8, CDH1, and VCAM-1.) are consistently deregulated in infected children and in adults with gastric cancer. Future studies should be designed to determine the clinical significance of these changes in infection-associated biomarkers in children and their persistence over time. The effect of eradication therapy over these biomarkers in children if proven significant, could lead to modifications in treatment guidelines for younger populations, and eventually promote the development of preventive strategies, such as vaccination, in the near future.

Muc5ac null mice are predisposed to spontaneous gastric antro-pyloric hyperplasia and adenomas coupled with attenuated H. pylori-induced corpus mucous metaplasia

Gastric cancer (GC) is the third leading cause of cancer-related deaths worldwide and is strongly associated with chronic Helicobacter pylori (Hp) infection. The ability of Hp to closely adhere to the gastric surface protective mucous layer containing mucins (MUC in humans and Muc in animals), primarily Muc5ac, is integral in the stepwise pathogenesis from gastritis to cancer. To probe the role of Muc5ac in Hp-induced gastric pathology, Muc5ac^-/- and Muc5ac^+/+ (WT) mice were experimentally infected with Hp Sydney strain (SS1). At 16 weeks and 32 weeks post infection (wpi), groups of mice were euthanized and evaluated for the following: gastric histopathological parameters, immunohistochemical expression of mucins (Muc5ac, Muc1, Muc2), Trefoil factor family proteins (Tff1 and Tff2), Griffonia (Bandeiraea) simplicifolia lectin II (GSL II) (mucous metaplasia marker) and Clusterin (Spasmolytic Polypeptide Expressing Metaplasia (SPEM) marker), Hp colonization density by qPCR and gastric cytokine mRNA levels. Our results demonstrate that Muc5ac^-/- mice developed spontaneous antro-pyloric proliferation, adenomas and in one case with neuroendocrine differentiation; these findings were independent of Hp infection along with strong expression levels of Tff1, Tff2 and Muc1. Hp-infected Muc5ac^-/- mice had significantly lowered gastric corpus mucous metaplasia at 16 wpi and 32 wpi (P = 0.0057 and P = 0.0016, respectively), with a slight reduction in overall gastric corpus pathology. GSII-positive mucous neck cells were decreased in Hp-infected Muc5ac^-/- mice compared to WT mice and clusterin positivity was noted within metaplastic glands in both genotypes following Hp infection. Additionally, Hp colonization densities were significantly higher in Muc5ac^-/- mice compared to WT at 16 wpi in both sexes (P = 0.05) along with a significant reduction in gastric Tnfα (16 wpi-males and females, P = 0.017 and P = 0.036, respectively and 32 wpi-males only, P = 0.025) and Il-17a (16 wpi-males) (P = 0.025). Taken together, our findings suggest a protective role for MUC5AC/Muc5ac in maintaining gastric antral equilibrium and inhibiting Hp colonization and associated inflammatory pathology.

Sera Antibody Repertoire Analyses Reveal Mechanisms of Broad and Pandemic Strain Neutralizing Responses after Human Norovirus Vaccination

Rapidly evolving RNA viruses, such as the GII.4 strain of human norovirus (HuNoV), and their vaccines elicit complex serological responses associated with previous exposure. Specific correlates of protection, moreover, remain poorly understood. Here, we report the GII.4-serological antibody repertoire—pre- and post-vaccination—and select several antibody clonotypes for epitope and structural analysis. The humoral response was dominated by GII.4-specific antibodies that blocked ancestral strains or by antibodies that bound to divergent genotypes and did not block viral-entry-ligand interactions. However, one antibody, A1431, showed broad blockade toward tested GII.4 strains and neutralized the pandemic GII.P16-GII.4 Sydney strain. Structural mapping revealed conserved epitopes, which were occluded on the virion or partially exposed, allowing for broad blockade with neutralizing activity. Overall, our results provide high-resolution molecular information on humoral immune responses after HuNoV vaccination and demonstrate that infection-derived and vaccine-elicited antibodies can exhibit broad blockade and neutralization against this prevalent human pathogen.

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Serum vaccine response is dominated by a small number of abundant antibody clonotypes

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Vaccine-boosted antibodies predominantly target conserved norovirus epitopes

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Identified cross-genogroup and strain-specific epitopes

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Discovered a pandemic-genotype neutralizing antibody recognizing a conserved epitope

Epigenetic downregulation of MUC17 by H. pylori infection facilitates NF-κB-mediated expression of CEACAM1-3S in human gastric cancer

BACKGROUND AND AIMS

Helicobacter pylori invades the mucosal barrier and infects the mucins of gastric epithelial cells. However, whether gastric carcinogenesis caused by H. pylori infection involves the membrane-bound mucins is unclear. This study explored the role of mucin 17 (MUC17) in gastric cancer (GC) associated with H. pylori infection.

METHODS

The expression of MUC17 and carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) was examined in human GC cells and tissues with H. pylori infection. Gain- and loss-of-function assays were performed to assess the role of MUC17 in regulating CEACAM1 in H. pylori-infected GC cells.

RESULTS

MUC17 was downregulated in H. pylori-infected GC cells and tissues in association with poor survival of GC patients. Downregulation of MUC17 was attributable to MUC17 promoter methylation mediated by DNA methyltransferase 1 (DNMT1) H. pylori-enhanced GC cell proliferation and colony formation associated with MUC17 downregulation. Gain- and loss-of-function assays showed that MUC17 inhibited the H. pylori-enhanced GC cell growth by preventing the translocation of H. pylori CagA into GC cells. Moreover, MUC17 downregulated the expression of CEACAM1 variant 3S (CEACAM1-3S) in GC cells and tissues with H. pylori infection. Additionally, MUC17 downregulated CEACAM1 promoter activity via attenuation of NF-κB activation in GC cells.

CONCLUSIONS

MUC17 was epigenetically downregulated in GC with H. pylori infection. MUC17 inhibited H. pylori CagA translocation via attenuation of NF-κB-mediated expression of CEACAM1-3S in GC cells. Thus, MUC17 may serve as a valuable prognostic biomarker for H. pylori-associated GC.

BabA-mediated adherence of pediatric ulcerogenic H. pylori strains to gastric mucins at neutral and acidic pH

Helicobacter pylori infection can result in non-ulcer dyspepsia (NUD), peptic ulcer disease (PUD), adenocarcinoma, and gastric lymphoma. H. pylori reside within the gastric mucus layer, mainly composed of mucins carrying an array of glycan structures that can serve as bacterial adhesion epitopes. The aim of the present study was to characterize the binding ability, adhesion modes, and growth of H. pylori strains from pediatric patients with NUD and PUD to gastric mucins. Our results showed an increased adhesion capacity of pediatric PUD H. pylori strains to human and rhesus monkey gastric mucins compared to the NUD strains both at neutral and acidic pH, regardless if the mucins were positive for Lewis b (Le^b), Sialyl-Lewis x (SLe^x) or LacdiNAc. In addition to babA positive strains being more common among PUD associated strains, H. pylori babA positive strains bound more avidly to gastric mucins than NUD babA positive strains at acidic pH. Binding to Le^b was higher among babA positive PUD H. pylori strains compared to NUD strains at neutral, but not acidic, pH. PUD derived babA-knockout mutants had attenuated binding to mucins and Le^b at acidic and neutral pH, and to SLe^x and DNA at acidic pH. The results highlight the role of BabA-mediated adherence of pediatric ulcerogenic H. pylori strains, and points to a role for BabA in adhesion to charged structures at acidic pH, separate from its specific blood group binding activity.

Upregulation of MUC5AC production and deposition of LEWIS determinants by HELICOBACTER PYLORI facilitate gastric tissue colonization and the maintenance of infection

Background

Helicobacter pylori bacteria colonize human gastric mucosa, cause chronic inflammation, peptic ulcers and gastric cancer. Colonization is mediated by H. pylori adhesins, which preferentially bind mucin 5 (MUC5AC) and Lewis (Le) determinants. The aim of this study was to evaluate the influence of H. pylori and their components on MUC5AC production and deposition of LeX/LeY in gastric epithelial cells in relation to bacterial adhesion using Caviae porcellus primary gastric epithelial cells and an in vivo model of experimental H. pylori infection in these animals.

Methods

MUCA5C and LeX/LeY were induced in vitro by live H. pylori reference strain CCUG 17874 (2 × 10⁷ CFU/ml), H. pylori glycine acid extract (GE), 10 μg/ml; cytotoxin associated gene A (CagA) protein, 1 μl/ml; UreA urease subunit, 5 μg/ml; lipopolysaccharide (LPS) 25 ng/ml and imaged by fluorescence microscopy after anti-MUC5AC or anti-LeX/LeY FITC antibody staining. Bacterial adhesion was imaged by using anti-H. pylori FITC antibodies. The animals were inoculated per os with H. pylori (3 times in 2 days intervals, 1 × 10¹⁰ CFU/ml). After 7 or 28 days an infection and inflammation were assessed by histological, serological and molecular methods. Gastric tissue sections of infected and control animals were screend for MUCA5C and LeX, and H. pylori adhesion as above.

Results

MUC5AC production and deposition of Lewis determinants, especially LeX were upregulated in the milieu of live H. pylori as well as GE, CagA, UreA or LPS in vitro and in vivo during infection, more effectively in the acute (7 days) than in the chronic (28 days) phase of infection. This was related to enhanced adhesion of H. pylori, which was abrogated by anti-MUC5AC and anti-LeX or anti-LeY antibody treatment.

Conclusions

Modulation of MUCA5C production and LeX/LeY deposition in the gastric mucosa by H. pylori can significantly increase gastric tissue colonization during H. pylori infection.

MUC1 and MUC5AC Acting on Helicobacter pylori-Related Deficiency and Solid Syndrome of Spleen and Stomach

To investigate the relationship of MUC1, MUC5AC, and the syndrome of spleen and stomach, 109 subjects (34 peptic ulcer (PU), 62 chronic gastritis (CG), and 13 healthy volunteers (CON)) were included. All the subjects included were surveyed with questionnaire to classify them into damp-heat syndrome of spleen and stomach (DHSS), spleen-qi deficiency syndrome (SQD), and CON, examined by gastric endoscope, and biopsied. Rapid urease and methylene blue staining (MBS) were performed on every subject to diagnose for Helicobacter pylori (Hp) infection, and both were defined as Hp-positive. Hematoxylin and eosin (HE) staining was performed on every specimen to explore the histomorphology, inflammatory degree, and inflammatory activity of different groups; then Elivision™ plus kit was used to test the expression of MUC1 and MUC5AC. All the results of digital images were reviewed by two experts blindly. The inflammatory degree with Hp infection was higher than those uninfected or CON, but no significant difference was found between DHSS and SQD. And the expressions of MUC5AC with positive Hp was higher than those with negative Hp or CON regardless of the deficiency and solid syndrome of spleen-stomach but not for MUC1. We speculate that the deficiency and solid syndrome of spleen-stomach is a condition like Tai Ji symbol of dynamic equilibrium, showing the higher expression of MUC5AC but no change of MUC1 in the circumstance of Hp infection.

Idiopathic Pulmonary Fibrosis: A Genetic Disease That Involves Mucociliary Dysfunction of the Peripheral Airways

Idiopathic pulmonary fibrosis (IPF) is an incurable complex genetic disorder that is associated with sequence changes in 7 genes (MUC5B, TERT, TERC, RTEL1, PARN, SFTPC, and SFTPA2) and with variants in at least 11 novel loci. We have previously found that 1) a common gain-of-function promoter variant in MUC5B rs35705950 is the strongest risk factor (genetic and otherwise), accounting for 30-35% of the risk of developing IPF, a disease that was previously considered idiopathic; 2) the MUC5B promoter variant can potentially be used to identify individuals with preclinical pulmonary fibrosis and is predictive of radiologic progression of preclinical pulmonary fibrosis; and 3) MUC5B may be involved in the pathogenesis of pulmonary fibrosis with MUC5B message and protein expressed in bronchiolo-alveolar epithelia of IPF and the characteristic IPF honeycomb cysts. Based on these considerations, we hypothesize that excessive production of MUC5B either enhances injury due to reduced mucociliary clearance or impedes repair consequent to disruption of normal regenerative mechanisms in the distal lung. In aggregate, these novel considerations should have broad impact, resulting in specific etiologic targets, early detection of disease, and novel biologic pathways for use in the design of future intervention, prevention, and mechanistic studies of IPF.

Helicobacter pylori in children

Helicobacter pylori infection in early childhood may differ in many aspects compared to infection in adulthood: the immune response in the gut, the type and prevalence of complications within and outside the stomach, and the impact on long-term health. In high prevalence countries, transient infections seem to be common in infants and toddlers, and the consequences of this phenomenon on the short- and long-term immune response are still unclear. Other controversial issues are related to the question of which H. pylori-infected children benefit from treatment and which is the best regimen to eradicate the infection in the presence of a worldwide increasing antibiotic resistance. The first large-scale randomized placebo-controlled vaccination trial in schoolchildren indicates that prevention of the infection may be possible.

Helicobacter pylori Infection in Pediatrics

This review includes the main pediatric studies published from April 2014 to March 2015. The host response of Treg cells with increases in FOXP3 and TGF-β1 combined with a reduction in IFN-γ by Teff cells may contribute to Helicobacter pylori susceptibility in children. Genotypic variability in H. pylori strains influences the clinical manifestation of the infection. Helicobacter pylori infection is associated with variables indicative of a crowded environment and poor living conditions, while breast-feeding has a protective effect. Intrafamilial infection, especially from mother to children and from sibling to sibling, is the dominant transmission route. Studies showed conflicting results regarding the association between H. pylori infection and iron deficiency anemia. One study suggests that H. pylori eradication plays a role in the management of chronic immune thrombocytopenic purpura in H. pylori-infected children and adolescents. The prevalence of H. pylori was higher in chronic urticaria patients than in controls and, following H. pylori eradication, urticarial symptoms disappeared. An inverse relationship between H. pylori infection and allergic disease was reported. Antibiotic resistance and insufficient compliance to treatment limit the efficacy of eradication therapy. Sequential therapy had no advantage over standard triple therapy. In countries where H. pylori infection is prevalent, studies focusing on virulence factors and antibiotic susceptibility may provide anticipation of the prognosis and may be helpful to reduce morbidity and mortality.