Expression of TFF2 and Helicobacter pylori infection in carcinogenesis of gastric mucosa

Organoid-Based Human Stomach Micro-Physiological System to Recapitulate the Dynamic Mucosal Defense Mechanism

Several stomach diseases are attributed to the dysregulation of physiological function of gastric mucosal barrier by pathogens. Gastric organoids are a promising tool to develop treatment strategies for gastric infections. However, their functional features of in vivo gastric mucosal barrier and host-microbe interactions are limited due to the lack of physiological stimuli. Herein, a human stomach micro-physiological system (hsMPS) with physiologically relevant gastric mucosal defense system is described based on the combination of organoid and MPS technology. A fluid flow enhanced epithelial-mesenchymal interaction in the hsMPS enables functional maturation of gastric epithelial cells, which allows for the recreation of mesh-like mucus layer containing high level of mucus protective peptides and well-developed epithelial junctional complexes. Furthermore, gastroprotection mechanisms against Helicobacter pylori (H. pylori) are successfully demonstrated in this system. Therefore, hsMPS represents a new in vitro tool for research where gastric mucosal defense mechanism is pivotal for developing therapeutic strategies.

Pyloric, pseudopyloric, and spasmolytic polypeptide-expressing metaplasias in autoimmune gastritis: a case series of 22 Japanese patients

There are two types of pyloric gland-like metaplasia in the corpus of stomach: pyloric and pseudopyloric metaplasias. They show the same morphology as the original pyloric glands in H&E staining. Pseudopyloric metaplasia is positive for pepsinogen (PG) I immunohistochemically, whereas pyloric metaplasia is negative. Recently, spasmolytic polypeptide-expressing metaplasia (SPEM) is proposed for pyloric gland-like metaplasia mainly in animal experiments. SPEM expresses trefoil factor family 2 (TFF2) and is often considered synonymous with pseudopyloric metaplasia. We reviewed consecutive 22 Japanese patients with autoimmune gastritis (AIG) to investigate TFF2 expression in pyloric and pseudopyloric metaplasias by counting all pyloric gland-like glands in biopsy specimens taken from greater curvature of the middle corpus according to the Updated Sydney System. Pyloric metaplasia was seen in all the 22 cases, and pseudopyloric metaplasia was found in 15 cases. Of 1567 pyloric gland-like glands in all the cases, 1381 (88.1%) glands were pyloric metaplasia glands, and the remaining 186 (11.9%) glands were pseudopyloric metaplasia glands. TFF2 expression was observed in pyloric or pseudopyloric metaplasia glands in 20 cases. TFF2 expression was recognized in 409 of 1381 (26.9%) pyloric metaplasia glands and 27 of 186 (14.5%) pseudopyloric metaplasia glands (P<0.01, chi-square test). In conclusion, SPEM was not always the same as pseudopyloric metaplasia in human AIG, and the majority of metaplasia in AIG was not pseudopyloric but pyloric metaplasia.

Trefoil Factor 2 Regulates Proliferation and Apoptosis of Pancreatic Cancer Cells and LPS-Induced Normal Pancreatic Duct Cells by β-Catenin Pathway

Introduction

Pancreatic cancer (PC) is a malignant tumor with poor prognosis. This study aimed to determine the role of trefoil factor 2 (TFF2) in the proliferation and apoptosis of LPS-induced normal pancreatic duct cells and pancreatic cancer cells through β-catenin pathway.

Methods

TFF2 expression in normal pancreatic duct cells, pancreatic cancer cells and LPS-induced normal pancreatic duct cells was detected by RT-qPCR analysis and Western blot analysis. The transfection effects in pancreatic cancer cells and LPS-induced normal pancreatic duct cells were analyzed by RT-qPCR analysis. After indicated transfection, proliferation, apoptosis and inflammation of these cells were respectively detected by CCK-8 assay, TUNEL assay and certain ELISA kits. Expression of β-catenin pathway-related proteins was analyzed by Western blot analysis. Co-immunoprecipitation assay determined the combination of TFF2 and β-catenin.

Results

TFF2 expression was increased in pancreatic cancer cells and LPS-induced HPDE cells compared with HPDE cells. According to TFF2 expression in these cells, PanC-1 cells and 5 μg/mL LPS were selected. In addition, TFF2 interference decreased the proliferation and promoted the apoptosis of PanC-1 cells and LPS-induced HPDE cells. However, TFF2 interference did not obviously change the levels of TNF-α, IL-1β and IL-6 in PanC-1 cells and LPS-induced HPDE cells. Furthermore, TFF2 interference suppressed the expression of β-catenin, c-Myc, Cyclin D1 and BIRC5 in PanC-1 cells and LPS-induced HPDE cells. TFF2 was demonstrated to combine with β-catenin.

Discussion

TFF2 interference inhibits proliferation and promotes apoptosis of PanC-1 cells and LPS-induced HPDE cells by suppressing β-catenin pathway.

Trefoil Factor Family Member 2 (TFF2) as an Inflammatory-Induced and Anti-Inflammatory Tissue Repair Factor

Trefoil factor family member 2 (TFF2) is known for its involvement in mucosal repair. Whereas it is overexpressed during inflammatory processes, adding TFF2 leads to an anti-inflammatory effect that would contribute to create the microenvironment required for tissue repair. These properties present TFF2 with a homeostatic pattern during inflammatory processes as illustrated by selected examples.

Histological changes associated with pyloric and pseudopyloric metaplasia after Helicobacter pylori eradication

Pyloric metaplasia (PM) and pseudopyloric metaplasia (PPM) are metaplastic changes resulting in pyloric-type glands in the gastric oxyntic mucosa that mainly occur in chronic gastritis caused by Helicobacter pylori (H. pylori) infection. Focusing on PM and PPM, we classified the histological changes in gastric mucosa according to the Updated Sydney System, using 314 biopsy specimens of gastric greater curvature of the middle body before H. pylori eradication (HPE). Next, the numbers of PM and PPM glands were counted in 47 specimens, and subjects were followed up over 10 years after HPE. PPM was recognized jointly with inflammation, activity, atrophy, and intestinal metaplasia, but PM was recognized more frequently than PPM as atrophy and intestinal metaplasia progressed. Both PM and PPM regressed significantly within 6 years after HPE. Additionally, we demonstrated that PM and PPM are not always coincident with spasmolytic polypeptide-expressing metaplasia (SPEM). In conclusion, PM and PPM are considered different modulations of the same line of differentiation, which are both reversible, with PM potentially emerging from PPM upon progression.

Oxyresveratrol ameliorates ethanol-induced gastric ulcer via downregulation of IL-6, TNF-α, NF-ĸB, and COX-2 levels, and upregulation of TFF-2 levels

Oxyresveratrol, an active ingredient of Artocarpus lakoocha, is known to possess anti-inflammatory and immunomodulatory properties. Current study investigates the immunomodulatory effect of oxyresveratrol in mouse model of ethanol-induced ulcer. Anti-ulcer effect was determined using histopathological evaluation (H&E staining) and different tests like, gastric ulcer scoring, ulcer index, total acid secretion, and gastric pH. The mRNA expression levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), nuclear factor-kappaB (NF-ĸB), cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2) and trefoil factor 2 (TFF-2) were evaluated using reverse transcription polymerase chain reaction (RT-PCR). The data showed marked percentage inhibition of erosion, hemorrhage, fibrinoid necrosis, inflammatory infiltrate, and ulcer in low (30 mg/kg b.w.) and high dose (50 mg/kg b.w.) groups of oxyresveratrol. Treatment with oxyresveratrol inhibited ulcer score and ulcer index as compared with disease control group. Oxyresveratrol significantly increased gastric pH (P < 0.001) and attenuated total acid (P < 0.001) secretion. RT-PCR analysis showed significant suppression in the mRNA expression levels of IL-6 (P < 0.001), TNF-α (P < 0.01), NF-ĸB (P < 0.001), and COX-2 (P < 0.05) in oxyresveratrol treated groups, while COX-1 expression levels were found unaltered. Treatment with oxyresveratrol significantly elevated (P < 0.01) the expression levels of cytoprotective TFF-2 levels. Similar Immunomodulatory and anti-ulcer effects were found with ranitidine treatment, which was used as a reference drug. In conclusion, oxyresveratrol possess significant anti-ulcer property which might be attributed to attenuated expression levels of IL-6, TNF-α, NF-ĸB, and COX-2 and elevated expression levels of TFF-2.

High salt diet can down-regulate TFF2 expression level in gastric mucosa of MGs after H. pylori infection

This study aimed to elucidate the effect of Helicobacter pylori (H. pylori) and high salt diet on Trefoil factor 2 (TFF2) expression level of Mongolian gerbils (MGs) gastric mucosa. The results of H. pylori identification and histopathology showed that H. pylori infected MGs model was built successfully. According to the immunohistochemical staining results, 25% (4/16) of H. pylori infected MGs with high salt diet showed high TFF2 expression, which was significantly lower than H. pylori infection group 61% (11/18)(P = 0.045). The results suggested that High salt diet could down-regulated TFF2 expression level of MGs gastric mucosa induced by H. pylori infection.

Trefoil factors: Gastrointestinal-specific proteins associated with gastric cancer

Trefoil factor family (TFF), composed of TFF1, TFF2, and TFF3, is a cluster of secreted peptides characterized by trefoil domain (s) and C-terminal dimerization domain. TFF1, a gastric tumor suppressor, is a single trefoil peptide originally detected in breast cancer cell lines but expressed mainly in the stomach; TFF2, a candidate of gastric cancer suppressor with two trefoil domains, is abundant in the stomach and duodenal Brunner's glands; and TFF3 is another single trefoil peptide expressed throughout the intestine which can promote the development of gastric carcinoma. According to multiple studies, TFFs play a regulatory function in the mammals' digestive system, namely in mucosal protection and epithelial cell reconstruction, tumor suppression or promotion, signal transduction and the regulation of proliferation and apoptosis. Action mechanisms of TFFs remain unresolved, but the recent demonstration of a GKN (gastrokine) 2-TFF1 heterodimer implicates structural and functional interplay with gastrokines. This review aims to encapsulate the structural and biological characteristics of TFF.

Increased expression of protease-activated receptor 4 and Trefoil factor 2 in human colorectal cancer

Protease-activated receptor 4 (PAR4), a member of G-protein coupled receptors family, was recently reported to exhibit decreased expression in gastric cancer and esophageal squamous cancer, yet increased expression during the progression of prostate cancer. Trefoil factor 2 (TFF2), a small peptide constitutively expressed in the gastric mucosa, plays a protective role in restitution of gastric mucosa. Altered TFF2 expression was also related to the development of gastrointestinal cancer. TFF2 has been verified to promote cell migration via PAR4, but the roles of PAR4 and TFF2 in the progress of colorectal cancer are still unknown. In this study, the expression level of PAR4 and TFF2 in colorectal cancer tissues was measured using real-time PCR (n = 38), western blotting (n=38) and tissue microarrays (n = 66). The mRNA and protein expression levels of PAR4 and TFF2 were remarkably increased in colorectal cancer compared with matched noncancerous tissues, especially in positive lymph node and poorly differentiated cancers. The colorectal carcinoma cell LoVo showed an increased response to TFF2 as assessed by cell invasion upon PAR4 expression. However, after intervention of PAR4 expression, PAR4 positive colorectal carcinoma cell HT-29 was less responsive to TFF2 in cell invasion. Genomic bisulfite sequencing showed the hypomethylation of PAR4 promoter in colorectal cancer tissues and the hypermethylation in the normal mucosa that suggested the low methylation of promoter was correlated to the increased PAR4 expression. Taken together, the results demonstrated that the up-regulated expression of PAR4 and TFF2 frequently occurs in colorectal cancer tissues, and that overexpression of PAR4 may be resulted from promoter hypomethylation. While TFF2 promotes invasion activity of LoVo cells overexpressing PAR4, and this effect was significantly decreased when PAR4 was knockdowned in HT-29 cells. Our findings will be helpful in further investigations into the functions and molecular mechanisms of Proteinase-activated receptors (PARs) and Trefoil factor factors (TFFs) during the progression of colorectal cancer.

Mucosal expression of aquaporin-4 in the stomach of histamine type 2 receptor knockout mice and Helicobacter pylori-infected mice

BACKGROUND AND AIM

Basolateral water channel, aquaporin-4 (AQP4), is known to be expressed in gastric parietal cells, especially in the basal side of gastric mucosa. However, the role of AQP4 in the stomach is still unknown. Histamine type 2 receptor (H2R) knockout mice, which are characterized by suppressed gastric acid secretion, are known as formation of mucosal hyperplasia with cystic dilatation and spasmolytic polypeptide-expressing metaplasia (SPEM) in the stomach. The aim of the present study is to investigate whether the expression of AQP4 is changed by the condition of acid suppression and Helicobacter pylori infection.

METHODS

Male H2 R knockout mice and their controls (C57BL/6) were used. H. pylori was orally infected at the age of 5 weeks. The distributions of AQP4 and H+/K+-ATPase in the gastric mucosa were investigated by fluorescent immunohistochemistry. The mRNA expressions of AQP4, H+/K+-ATPase, sonic hedgehog (Shh), and trefoil factor-2 (TFF2) were investigated by quantitative reverse transcription polymerase chain reaction (RT-PCR).

RESULTS

In the H2 R knockout mice, the distribution of AQP4-positive parietal cells was extended toward the surface of the fundic glands. Although the mRNA expression levels of AQP4 and H+/K+ATPase were elevated in H2 R knockout mice at the age of 20 weeks, the elevations were not maintained by aging or H. pylori infection. In H2 R knockout mice with H. pylori infection, the expression level of TFF2 mRNA was elevated while the ratio between AQP4 and H+/K+ ATPase mRNA expression was decreased compared with the H2 R knockout mice without H. pylori infection.

CONCLUSIONS

In the H2 R knockout mice, massive SPEM was induced by H. pylori colonization and the ratio between AQP4 and H+/K+ATPase mRNA expression was decreased.

Promoter hypermethylation and downregulation of trefoil factor 2 in human gastric cancer

Trefoil factor 2 (TFF2) plays a protective role in gastric mucosa and may be involved in the progression of gastric cancer, but the detailed functions and underlying molecular mechanisms are not clear. The present study used a combination of clinical observations and molecular methods to investigate the correlation between abnormal expression of TFF2 and gastric cancer progression. TFF2 expression was evaluated by reverse transcription polymerase chain reaction (RT-PCR), quantitative PCR (qPCR), and western blot and immunohistochemistry analyses. TFF2 methylation levels were analyzed by genomic bisulfite sequencing method. The results showed that TFF2 mRNA and protein expression were decreased in gastric cancer tissues compared with the matched non-cancerous mucosa, and the decreased level was associated with the differentiation and invasion of gastric cancer. Moreover, the average TFF2 methylation level of CpG sites in the promoter region was 70.4% in three gastric cancer tissues, while the level in associated non-neoplastic tissues was 41.0%. Furthermore, the promoter hypermethylation of TFF2 was also found in gastric cancer cell lines, AGS and N87, and gene expression was significantly increased following treatment with a demethylating agent, 5-Aza-2′-deoxycytidine. In conclusion, TFF2 expression was markedly decreased in gastric cancer and promoter hypermethylation was found to regulate the downregulation of TFF2. TFF2 has been suggested as a tumor suppressor in gastric carcinogenesis and metastasis.

p53 inhibition of AP1-dependent TFF2 expression induces apoptosis and inhibits cell migration in gastric cancer cells

Overexpression of trefoil factor 2 (TFF2) is associated with increased cell migration, resistance to apoptosis, and possibly increased gastric cancer invasion. Dysregulation of p53 is frequently observed in preneoplastic conditions of the stomach. Here, we investigated the effect of p53 on the expression and function of TFF2 in gastric cancer cell lines. Gene expression was determined by reverse transcription-polymerase chain reaction, and promoter activity was assessed by dual luciferase reporter assays. Apoptosis was detected by flow cytometry, and cell migration was evaluated by the Boyden chamber assay. Exogenous expression of p53 dose dependently inhibited endogenous TFF2 mRNA, protein, and promoter activity and resulted in induction of cell apoptosis and inhibition of cell migration. Downregulation of TFF2 by small interfering RNA sensitized gastric cancer cells to drug-induced p53-dependent apoptosis. Addition of human TFF2 peptide reversed p53-dependent apoptosis and inhibition of cell migration. The p53-responsive element was mapped to an AP-1-like cis-element at -182 bp upstream of the TFF2 transcription start site. Mutation of this AP-1-like element abrogated p53-mediated inhibition of TFF2 promoter activity. Gel shift and chromatin immunoprecipitation assays demonstrated that c-Jun and c-Fos bind to this AP-1-like element. Ectopic expression of c-Jun/c-Fos or p300 or treatment of cells with phorbol 12-myristate 13-acetate (PMA) stimulated endogenous TFF2 mRNA expression and promoter activity, and p53 inhibited the effects of AP-1 and PMA on TFF2. p53 induces cell apoptosis and inhibits cell migration in part by downregulating TFF2 expression through an AP-1-like site, suggesting that TFF2 may be an important downstream target of p53.

Intestinal metaplasia: a premalignant lesion involved in gastric carcinogenesis

Despite a plateau in incidence, gastric cancer remains a significant problem globally. The majority of gastric cancer is associated with histologically recognizable premalignant stages as first described by Pelayo Correa in the mid-1970s. The mortality from gastric cancer remains high especially in Western countries where, arguably, the index of suspicion of gastric cancer in patients presenting with upper abdominal symptoms is lower than in high prevalence countries. What is the evidence that intestinal metaplasia (IM) is a premalignant condition? What should the clinician know about IM and the relative risks of progression to gastric cancer? Finally, what are the current and future strategies that may help stratify patients into high risk and low risk for the development of gastric cancer? This review focuses on gastric IM and outlines some of the literature that discusses it as a premalignant condition. It also reviews the issue of surveillance of patients with IM in order to attempt to reduce the significant mortality of gastric cancer by detection of earlier stages of disease which are eminently treatable.

Gastric mucus alterations associated with murine Helicobacter infection

The C57BL/6 mouse has been shown to develop gastric adenocarcinoma after Helicobacter felis infection. This model was used to determine whether mucin and trefoil factor (TFF) expression after infection was altered in a similar fashion to the changes seen in the protective gastric mucus layer of the human stomach after H. pylori infection. Our results indicate that this mouse model mimics many of the changes seen after human H. pylori infection, including increased expression of muc4 and muc5b and loss of muc5ac. These alterations in mucin expression occurred as early as 4 weeks postinfection, before the development of significant mucous metaplasia or gastric dysplasia. The decrease in muc5ac expression occurred only in the body of the stomach and was not secondary to the adaptive immune response to infection, because a similar decrease in expression was seen after infection of B6.Rag-1(-/-) mice, which lack B and T cells. Intriguingly, the increased expression of Muc4 and Muc5b in infected C57BL/6 mice was not seen in the infected B6.Rag-1(-/-) mice. Because B6.Rag-1(-/-) mice do not develop gastric pathology after H. felis infection, these findings point to the potential role of Muc4 and Muc5b in disease progression. This manuscript contains online supplemental material at http://www.jhc.org. Please visit this article online to view these materials.

Reduced Shh expression in TFF2-overexpressing lesions of the gastric fundus under hypochlorhydric conditions

Expression of sonic hedgehog (Shh), a morphogen for the gastric fundic glands, is reduced in the atrophic mucosa that develops in association with Helicobacter pylori infection, resulting in impaired differentiation of the fundic gland cells, increased expression of trefoil factor family 2 (TFF2) and the formation of spasmolytic polypeptide (SP)-expressing metaplasia (SPEM), a preneoplastic lesion. However, it is still unresolved whether H. pylori-induced inflammation and the resultant reduction in parietal cell number or reduced parietal cell function per se reduces Shh expression. The present study was designed to clarify the expression of Shh and TFF2 in the context of parietal cell dysfunction in the absence of inflammation, using histamine H(2) receptor-knockout (H(2)R-null) mice and an acid exposure model. Age-matched H(2)R-null mice and wild-type (WT) mice were used. The expression of Shh and TFF2 mRNA was quantified by quantitative RT-PCR. Immunohistochemistry was also performed to detect the expression of Shh, TFF2 and cell markers. To study the effects of acid exposure, HCl solution was administered to the animals. The H(2)R-null mice exhibited higher gastric pH, increased TFF2 expression and reduced Shh expression. Impaired mucous neck-to-zymogenic cell differentiation was observed in the H(2)R-null mice. Furthermore, Shh expression increased in the presence of gastric acid and showed a significant correlation with gastric surface pH. In conclusion, our results suggest that persistent parietal cell dysfunction alone (suppressed gastric acid secretion), in the absence of inflammation or parietal cell loss caused by H. pylori infection, may be sufficient to down-regulate Shh expression in TFF2-overexpressing preneoplastic lesions of the gastric fundus. Since exposure to acid restored fundic Shh expression, appropriate gastric acid secretion may play an important role in the morphogen dynamics involved in the maintenance of gastric fundic gland homeostasis.

In vitro activity of IgY against recombinant VacA protein of Helicobacter pylori

AIM: To explore the physicochemical and biolo-gical properties of IgY extracted from the yolk of hen's egg immunized with recombinant VacA protein of Helicobacter pylori.

METHODS: The purified antigen of recombinant VacA was used to immunize the hens and the VacA-IgY antibody was extracted from the yolk of hen's egg by water dilution methods and then purified by deposition technique with ammonium sulfate. In order to evaluate VacA-IgY heat stability, the titer of VacA-IgY was detected by enzyme-linked immunosorbent assay (ELISA) after being heated for 15 min under different temperatures. VacA-IgY was added into Tris-HCl of different pH values and incubated under a temperature of 37℃ to access its acid stability using ELISA. The competence of anti-pepsin digestion was also measured by ELISA. The VacA⁺H. pylori were co-cultured with Hela cells and VacA-IgY antibody was added to observe its neutralization on the cytotoxity of H. pylori by MTT assay in vitro.

RESULTS: The activity of VacA-IgY was maintained about 50% after water baths (70℃, 15 min). The activity of VacA-IgY seldom changed at pH values 5.0-7.0, but declined rapidly below the pH value 5.0, even absolutely disappeared at pH value 2.0. After incubation with pepsin (pH4.0, 60 kU/L) for 1 h, the activity of VacA-IgY had no changes, and 2 h after incubation, it still maintained over 50%. The VacA-IgY antibody neutralized the cytotoxity of VacA⁺H. pylori in a concentration-dependent manner. VacA⁺H. pylori ultrasonic extracts inhibited 50% proliferation of Hela cells at a concentration of 20 mg/L, while VacA-IgY completely neutralized the cytotoxity of H. pylori at concentrations of 80-320 mg/L (P < 0.01).

CONCLUSION: The VacA-IgY antibody shows a good heat stability, certain acid stability, and competence of anti-pepsin digestion, and can neutralize the cytotoxity of VacA protein of H. pylori effectively in vitro.

Profiling of microdissected gastric epithelial cells reveals a cell type-specific response to Helicobacter pylori infection

BACKGROUND AND AIMS

Helicobacter pylori colonizes the epithelial lining of the human stomach and is associated with disorders ranging from chronic gastritis to peptic ulcers and gastric cancer. We have explored the transcriptional response of the epithelium globally by applying a whole-genome approach to a murine model of infection.

METHODS

The 3 major epithelial lineages of the stomach-the parietal, mucus-producing, and chief cells-were harvested from cryosections of infected and uninfected murine stomachs by laser microdissection and subjected to gene expression profiling. The localization and quantity of selected transcripts were verified by in situ hybridization and quantitative real-time reverse-transcription polymerase chain reaction.

RESULTS

Each cell type is characterized by a transcriptional signature profile. The parietal cell profile is highly enriched for factors involved in mitochondrial energy generation, whereas the chief cell predominantly expresses digestive enzymes and glycosylation-associated proteins. In contrast, the mucus cell signature is distinguished by an abundance of cell-surface receptors, signaling molecules, and factors involved in antigen presentation. All of these indicate a role in sampling, sensing, and responding to environmental stimuli. In line with this biological function, we measured a strong transcriptional response to Helicobacter pylori infection only in this cell type. The genes that are differentially expressed upon infection are implicated in a proinflammatory and mucosal defense response as well as modulation of angiogenesis, iron availability, and tumor suppression.

CONCLUSIONS

Laser microdissection-assisted transcriptional profiling is a useful tool to explore the biology of specific cell populations and is sensitive enough to measure the transcriptional response to bacterial infection in vivo.

Aberrant epithelial expression of trefoil family factor 2 and mucin 6 in Helicobacter pylori infected gastric antrum, incisura, and body and its association with antralisation

AIMS

To determine gastric expression of trefoil family factor 2 (TFF2) and MUC6 in Helicobacter pylori positive and negative subjects, and its association with antralisation at the gastric incisura.

METHODS

Gastric biopsies from the antrum, incisura, and body of 76 dyspeptic patients without ulcers were used for the determination of H. pylori infection, histological changes, and epithelial TFF2 and MUC6 expression.

RESULTS

In the foveola, the rates of TFF2 and MUC6 immunostaining were greater in H. pylori infected (n = 27) than in uninfected patients (n = 49) at the antrum (59.3% v 4.1% for TFF2 and 63.0% v 4.1% for MUC6; both p < 0.001) and incisura (44.4% v 2.0% for TFF2 and 48.1% v 0% for MUC6; both p < 0.001). In the deeper glands, the rates were also greater in H. pylori infected than in uninfected patients at the incisura (85.2% v 22.4% for both TFF2 and MUC6; p < 0.001). Antral-type mucosa was present at the incisura in 28 of the 76 patients. TFF2 and MUC6 expression in the foveola and deeper glands was significantly associated with antral-type mucosa, independent of H. pylori status.

CONCLUSIONS

Helicobacter pylori infection increases the expression of TFF2 and MUC6 in the gastric epithelium. Aberrant TFF2 and MUC6 expression is associated with antralisation of gastric incisura.

Prokaryotic expression of fusion gene of vacuolating segment of vacA and hpaA in Helicobacter pylori

AIM: The prokaryotic expression vector of the fusion gene with v segment of the vacuolating cytotoxin and hpaA of Helicobacter pylori (H. pylori) was constructed and expressed. It would lay a foundation for prophylaxis and therapy of H. pylori infection.

METHODS: By using the primer with a fragment encoding 12 amino acids of N-terminal of human interleukin-3 (IL-3), the vacuolating cytotoxin gene of Hp with linker was amplified from pQE30-V plasmid by PCR. The gene was cloned into plasmid pTrc99A-HpaA and fused with the hpaA gene. The fusion gene was cloned into prokaryotic expression vector pQE30. The recombinant plasmid of pQE30-V-HpaA was transformed into E.coli. DH5a and expressed in the presence of IPTG. The expression product was analyzed by SDS-PAGE, its antigenicity of the expression product was identified by Western blotting.

RESULTS: Mr of recombinant protein was about 65 000 and represented 35% total protein of E.coli. Western blotting showed the recombinant protein could be recognized by the antiserum against H. pylori.

CONCLUSION: The fusion gene and its prokaryotic expression vector pQE30-V-HpaA is constructed and expressed in DH5asuccessfully. It provides the antigen basis for further studying the biological function of fusion protein and obtaining vaccine against the infection of H. pylori.

Expression of trefoil peptides in the subtypes of intestinal metaplasia

We studied the expression of trefoil peptides in the different types of intestinal metaplasia of the stomach. Endoscopic biopsy was performed in 132 patients with dyspepsia. Intestinal metaplasia subtype was classified according to the pattern of alcian blue/PAS staining and high iron diamine staining. Expression of trefoil peptides was measured by immunohistochemistry. TFF1 and TFF3 were mainly expressed in goblet cells and TFF2 in columnar cells in all the types of intestinal metaplasia. There was a gradual decrease of TFF1 and TFF3, and increase of TFF2, during the progression of intestinal metaplasia from type I to type III via the type II intermediate.

Influence of H. pylori on cyclinD1 and PCNA mRNA expression in HepG2 cell line

AIM: To observe the effects of Helicobacter pylori (H. pylori) on cyclinD1 and PCNA mRNA expression in a human hepatoma cell line HepG2.

METHODS: H. pylori was co-cultured with HepG2 for 1, 3,6, 12 and 24 h. The cyclinD1 and PCNA mRNA expression was detected by semi-quantitative RT-PCR.

RESULTS: When HepG2 cells were cocultured with H. pylori CagA⁺ strain, the amount of cyclinD1 mRNA was increased 4.0-fold by 3 h and PCNA mRNA was increased 2.0-fold by 6 h, compared with that of uninfected control. Neither cyclinD1 mRNA nor PCNA mRNA of the HepG2 cells was increased after incubation with H. pylori CagA^- strain.

CONCLUSION: H. pylori can induce increasing expression of cyclinD1 and PCNA mRNA in HepG2, which may play some roles in the development of hepatocellular carcinoma.