Trefoil Factor Family: A Troika for Lung Repair and Regeneration

Tissue damage in the upper and lower airways caused by mechanical abrasion, noxious chemicals, or pathogenic organisms must be followed by rapid restorative processes; otherwise, persistent immunopathology and disease may ensue. This review will discuss evidence for the important role served by trefoil factor (TFF) family members in healthy and diseased airways of humans and rodents. Collectively, these peptides serve to both maintain and restore homeostasis through their regulation of the mucous layer and their control of cell motility, cell differentiation, and immune function in the upper and lower airways. We will also discuss important differences in which trefoil member tracks with homeostasis and disease between humans and mice, which poses a challenge for research in this area. Moreover, we discuss new evidence supporting newly identified receptor binding partners in the leucine-rich repeat and immunoglobulin-like domain-containing NoGo (LINGO) family in mediating the biological effects of TFF proteins in mouse models of epithelial repair and infection. Recent advances in our knowledge regarding TFF peptides suggest that they may be reasonable therapeutic targets in the treatment of upper and lower airway diseases of diverse etiologies. Further work understanding their role in airway homeostasis, repair, and inflammation will benefit from these newly uncovered receptor-ligand interactions.

Pretreatment with intestinal trefoil factor alleviates stress-induced gastric mucosal damage via Akt signaling

BACKGROUND

Stress-related gastric mucosal damage or ulcer remains an unsolved issue for critically ill patients. Stress ulcer prophylaxis has been part of routine intensive care, but uncertainty and controversy still exist. Co-secreted with mucins, intestinal trefoil factor (ITF) is reported to promote restitution and regeneration of intestinal mucosal epithelium, although the mechanism remains unknown.

AIM

To elucidate the protective effects of ITF on gastric mucosa and explore the possible mechanisms.

METHODS

We used a rat model of gastric mucosal damage induced by water immersion restraint stress and lipopolysaccharide-treated human gastric epithelial cell line to investigate the potential effects of ITF on damaged gastric mucosa both in vivo and in vitro.

RESULTS

ITF promoted the proliferation and migration and inhibited necrosis of gastric mucosal epithelia in vitro. It also preserved the integrity of gastric mucosa by upregulating expressions of occludin and zonula occludens-1. In the rat model, pretreatment with ITF ameliorated the gastric mucosal epithelial damage and facilitated mucosal repair. The protective effects of ITF were confirmed to be exerted via activation of Akt signaling, and the specific inhibitor of Akt signaling LY249002 reversed the protective effects.

CONCLUSION

ITF might be a promising candidate for prevention and treatment of stress-induced gastric mucosal damage, and further studies should be undertaken to verify its clinical feasibility.

Serum perfluoroalkyl substances (PFAS) and risk of asthma and various allergies in adolescents. The Tromsø study Fit Futures in Northern Norway

BACKGROUND

Exposure to environmental pollutants may contribute to the development of asthma and other allergies. The aim of this study was to investigate possible associations between asthma and other allergies with exposure to perfluoroalkyl substances (PFASs) in adolescents from the Arctic region of Norway.

METHODS

The Tromsø study Fit Futures 1 (TFF1) and 3-year follow-up Fit Futures 2 study (TFF2) included 675 adolescents that completed a questionnaire about health conditions and underwent a clinical examination with blood tests and fractional nitric oxide (FeNO) measurement. Serum concentrations of 18 PFASs were measured by UHPLC-MS/MS method.

RESULTS

Total PFASs (ΣPFAS) serum concentration over 4th quartile was positively associated with asthma in the TFF1 (OR 3.35 (95% CI 1.54-7.29), p = 0.002). Total perfluorooctane sulfonate (ΣPFOS), linear PFOS (linPFOS), linear perfluorohexane sulfonate (linPFHxS) concentrations over 4th quartiles were associated with 2 times higher odds of asthma in the TFF1. The positive associations between ΣPFAS, ΣPFOS, linPFOS and asthma remained statistically significant in the TFF2. ΣPFAS and linPFHxS concentrations over 3rd tertiles were associated with positive marker of eosinophilic airways inflammation FeNO> 25 ppb. Concentrations of ΣPFOS and linPFOS over 3rd quartiles were positively associated with self-reported nickel allergy (OR 2.25 (95% CI 1.17-4.35) p = 0.016 and OR 2.53 (95% CI 1.30-4.90) p = 0.006, respectively). Allergic rhinitis, self-reported pollen allergy, food allergy and atopic eczema were not associated with PFASs concentrations.

CONCLUSIONS

This study of Norwegian adolescents showed a positive association between several PFASs and asthma, as well as between PFOS and nickel allergy.

[Study on Variation of Gastroprotective Effect of Atractylodes lancea Rhizome Before and After Processing]

OBJECTIVE

To compare the gastroprotective effect between the crude and bran-processed Atractylodes lancea rhizome in the rat model of gastric ulcer.

METHODS

The model of gastric ulcer was imitated by acetic acid in rats. The levels of epidermal growth factor( EGF) and trefoil factor 2( TFF2) in serum and stomach were determined by the double-antibody sandwich enzyme-linked immunosorbent assay( ELISA),and the mRNA expressions of EGF and TFF2 in stomach were analyzed by quantitative real-time reverse transcription polymerase chain reaction( RT-PCR). The protein expressions of EGF and TFF2 in stomach were examined by immunohistochemistry.

RESULTS

The productions of EGF,TFF2 and the mRNA expressions of EGF and TFF2 were notably up-regulated by both crude Atractylodes lancea rhizome and bran-processed Atractylodes lancea rhizome. Compared with the crude Atractylodes lancea rhizome,the processed Atractylodes lancea rhizome was more effective.

CONCLUSION

The gastroprotective effect of Atractylodes lancea rhizome was enhanced after stir-frying with wheat bran in the rat model of gastric ulcer induced by acetic acid.

Effects of ezrin knockdown on the structure of gastric glandular epithelia

Ezrin, an adaptor protein that cross-links plasma membrane-associated proteins with the actin cytoskeleton, is concentrated on apical surfaces of epithelial cells, especially in microvilli of the small intestine and stomach. In the stomach, ezrin is predominantly expressed on the apical canalicular membrane of parietal cells. Transgenic ezrin knockdown mice in which the expression level of ezrin was reduced to <7% compared with the wild-type suffered from achlorhydria because of impairment of membrane fusion between tubulovesicles and apical membranes. We observed, for the first time, hypergastrinemia and foveolar hyperplasia in the gastric fundic region of the knockdown mice. Dilation of fundic glands was observed, the percentage of parietal and chief cells was reduced, and that of mucous-secreting cells was increased. The parietal cells of knockdown mice contained dilated tubulovesicles and abnormal mitochondria, and subsets of these cells contained abnormal vacuoles and multilamellar structures. Therefore, lack of ezrin not only causes achlorhydria and hypergastrinemia but also changes the structure of gastric glands, with severe perturbation of the secretory membranes of parietal cells.

[Construction and screening effective sequence of shRNA targeting human trefoil factor 3]

OBJECTIVE

Trefoil factor 3 plays a pivot role in oncogenic transformation, growth and metastatic extension of solid tumours besides mucosal protection. We screened the best siRNA sequence targeting human TFF3 by the transient-transfection of the lentiviral mediated shRNA into thyroid carcinoma K1 cells which secrete TFF3 themselves.

METHOD

Four siRNA transcription template hairpin structure target potential sites in human TFF3 mRNA sequence(132,170,258 and 537 bp,seperately) were selected and synthesized,as well as one negative shRNA(shRNAC). After annealing in vitro, insert pLVX-shRNA-puro construct recombinant plasmid, then enzyme digestion and sequencing analysis. The lentiviral-shRNAs were transient-transfected into K1 cells. TFF3 mRNA and protein levels were test by real-time PCR and western blot respectively in K1 cells at 48h post transient-transfected.

RESULT

Genetic mutations in two sequences of shRNA1~2, so the follow-up study terminated. The TFF3 expression were obviously inhibited in K1 cells at 48 hours post transient-transfected of shRNA3 and shRNA4. TFF3 (258-276) showed the highest silencing efficiency (TFF3 mRNA reduced 60.67% and TFF3 protein reduced 56.44%, P < 0.01) when the transfection efficiency was 76.83%.

CONCLUSION

pLVX-shRNA-puro-TFF3 expression plamid were successfully constructed and the highest efficiency sequences were screened. All these laid a foundation for further study about the function of TFF3 gene.

Host-defense and trefoil factor family peptides in skin secretions of the Mawa clawed frog Xenopus boumbaensis (Pipidae)

Peptidomic analysis of norepinephrine-stimulated skin secretions from the octoploid Mawa clawed frog Xenopus boumbaensis Loumont, 1983 led to the identification and characterization of 15 host-defense peptides belonging to the magainin (two peptides), peptide glycine-leucine-amide (PGLa; three peptides), xenopsin precursor fragment (XPF; three peptides), caerulein precursor fragment (CPF; two peptides), and caerulein precursor fragment-related peptide (CPF-RP; five peptides) families. In addition, caerulein and three peptides with structural similarity to the trefoil factor family (TFF) peptides, xP2 and xP4 from Xenopus laevis were also present in the secretions. Consistent with data from comparisons of the nucleotides sequence of mitochondrial and nuclear genes, the primary structures of the peptides suggest a close phylogenetic relationship between X. boumbaensis and the octoploid frogs Xenopus amieti and Xenopus andrei. As the three species occupy disjunct ranges within Cameroon, it is suggested that they diverged from a common ancestor by allopatric speciation.

[Continual self-renewal of the gastric epithelium by cell differentiation: implications for carcinogenesis]

BACKGROUND

The gastric mucosa and its glands represent a close interactive barrier to the outside world. This delicate surface is protected by a multilayered mucus barrier which contains among others the mucins MUC5AC and MUC6 and the trefoil factor family peptide TFF2. Furthermore, two types of gastric glands form delicate homeostatic systems, i.e. the fundic and antral glands, which show continual bidirectional self-renewal via differentiation from stem and progenitor cells. It was the aim of this study to analyze the self-renewal of these gastric units.

MATERIAL AND METHODS

Three characteristic regions (i.e. foveolar, proliferative zone and lower gland regions) were isolated from fundic and antral units by the use of laser microdissection and expression profiles concerning known marker genes were generated by reverse transcription polymerase chain reaction (RT-PCR) analysis.

RESULTS

The surface mucous cells (SMCs) of fundic and antral units characteristically differed in the expression of certain secretory genes. Furthermore, the maturation of mucous neck cells and their trans-differentiation into chief cells as well as the maturation of antral SMCs and antral gland cells occurred in a stepwise manner.

DISCUSSION

The correct maturation particularly of mucous neck cells and their trans-differentiation into chief cells is critical for homeostatic self-renewal of fundic units. Dysregulation of this multistep process can result in generation of the spasmolytic polypeptide-expressing metaplasia (SPEM) lineage which is characterized by its strong ectopic TFF2 expression. Chronic inflammation is known to support SPEM formation. The SPEM lineage is a precancerous lesion which can further differentiate into intestinal metaplasia.

Association between Promoter Polymorphisms of TFF1, TFF2, and TFF3 and the Risk of Gastric and Diffuse Gastric Cancers in a Korean Population

Gastric cancer is one of the most common cancers in the world. The aims of this study were to evaluate the association between polymorphisms in TFF gene family, TFF1, TFF2, and TFF3 and the risk of gastric cancer (GC) and GC subgroups in a Korean population via a case-control study. The eight polymorphisms in TFF gene family were identified by sequencing and genotyped with 377 GC patients and 396 controls by using TaqMan genotyping assay. The rs184432 TT genotype of TFF1 was significantly associated with a reduced risk of GC (odds ratio, [OR) = 0.45; 95% confidence interval, [CI] = 0.25-0.82; P = 0.009), more protective against diffuse-type GC (OR = 0.20; 95% CI = 0.05-0.89; P = 0.035) than GC (OR = 0.34; 95% CI = 0.14-0.82; P = 0.017) in subjects aged < 60 yr, and correlated with lymph node metastasis negative GC and diffuse-type GC (OR = 0.44; 95% CI = 0.23-0.86; P = 0.016 and OR = 0.20; 95% CI = 0.05-0.87; P = 0.031, respectively). In addition, a decreased risk of lymph node metastasis negative GC and diffuse-type GC was observed for rs225359 TT genotype of TFF1 (OR = 0.46, 95% CI = 0.24-0.88; P = 0.020 and OR = 0.21, 95% CI = 0.05-0.88; P = 0.033, respectively). These findings suggest that the rs184432 and rs225359 polymorphisms in TFF1 have protective effects for GC and contribute to the development of GC in Korean individuals.

Integrative Analysis of the Developing Postnatal Mouse Heart Transcriptome

In mammals, cardiomyocytes rapidly proliferate in the fetus and continue to do so for a few more days after birth. These cardiomyocytes then enter into growth arrest but the detailed molecular mechanisms involved have not been fully elucidated. We have addressed this issue by comparing the transcriptomes of 2-day-old (containing dividing cardiomyocytes) with 13-day-old (containing growth arrested cardiomyocytes) postnatal mouse hearts. We performed comparative microarray analysis on the heart tissues and then conducted Functional annotation, Gene ontology, KEGG pathway and Gene Set enrichment analyses on the differentially expressed genes. The bioinformatics analysis revealed that gene ontology categories associated with the “cell cycle”, “DNA replication”, “chromosome segregation” and “microtubule cytoskeleton” were down-regulated. Inversely, “immune response”, “extracellular matrix”, “cell differentiation” and “cell membrane” were up-regulated. Ingenuity Pathways Analysis (IPA) has revealed that GATA4, MYH7 and IGF1R were the key drivers of the gene interaction networks. In addition, Regulator Effects network analysis suggested that TASP1, TOB1, C1orf61, AIF1, ROCK1, TFF2 and miR503-5p may be acting on the cardiomyocytes in 13-day-old mouse hearts to inhibit cardiomyocyte proliferation and G1/S phase transition. RT-qPCR was used to validate genes which were differentially expressed and genes that play a prominent role in the pathways and interaction networks that we identified. In sum, our integrative analysis has provided more insights into the transcriptional regulation of cardiomyocyte exit from the cell cycle during postnatal heart development. The results also pinpoint potential regulators that could be used to induce growth arrested cardiomyocytes to proliferate in the infarcted heart.

Trefoil Factor 3 (TFF3) Is Regulated by Food Intake, Improves Glucose Tolerance and Induces Mucinous Metaplasia

Trefoil factor 3 (TFF3), also called intestinal trefoil factor or Itf, is a 59 amino acid peptide found as a homodimer predominantly along the gastrointestinal tract and in serum. TFF3 expression is elevated during gastrointestinal adenoma progression and has been shown to promote mucosal wound healing. Here we show that in contrast to other trefoil factor family members, TFF1 and TFF2, TFF3 is highly expressed in mouse duodenum, jejunum and ileum and that its expression is regulated by food intake. Overexpression of TFF3 using a recombinant adeno-associated virus (AAV) vector, or daily administration of recombinant TFF3 protein in vivo improved glucose tolerance in a diet-induced obesity mouse model. Body weight, fasting insulin, triglyceride, cholesterol and leptin levels were not affected by TFF3 treatment. Induction of mucinous metaplasia was observed in mice with AAV-mediated TFF3 overexpression, however, no such adverse histological effect was seen after the administration of recombinant TFF3 protein. Altogether these results suggest that the therapeutic potential of targeting TFF3 to treat T2D may be limited.

Trefoil Factor Expression in a Human Model of the Early Stages of Barrett's Esophagus

BACKGROUND

Trefoil proteins are believed to have an important role in mucosal protection and repair in the gastrointestinal tract. They are well recognized in Barrett's esophagus and considered a potential biomarker for the condition. Metaplasia occurring in the esophageal remnant after esophagectomy is a human model for the early stages of development of Barrett's esophagus.

AIMS

To assess expression of trefoil proteins in post-esophagectomy columnar epithelium and to use trefoils as a molecular tool to understand regenerative mucosa in the esophagus.

METHODS

Patients with columnar metaplasia in the esophageal remnant were recruited from a large esophago-gastric cancer center. Trefoil factor expression was determined using immunohistochemical techniques.

RESULTS

Samples were obtained from 37 patients. TFF1 and TFF2 were expressed by all samples in a similar pattern to that described in studies of sporadic Barrett's esophagus. TFF3 was less widely expressed and was significantly associated with time elapsed between surgery and endoscopy. Median time from surgery to endoscopy was 8.1 years for patients with TFF3 expression versus 3.4 years for those without (p = 0.004).

CONCLUSIONS

Widespread expression of trefoils in this environment suggests that these proteins have an important role in development of Barrett's metaplasia. TFF3 expression may be absent in the early stages of metaplasia and may represent more established columnar epithelium. Biopsy samples from post-esophagectomy patients provide a valuable resource to study the early stages of Barrett's esophagus.

[Effect of Rhizoma Atractylodis extract in protecting gastric mucosa and modulating gastrointestinal immune function in a rat model of spleen deficiency]

OBJECTIVE

To investigate the effect of Rhizoma Atractylodis extract (ERA) in protecting gastric mucosa and modulating gastrointestinal immune function of a rat model of spleen deficiency syndrome and elucidate the mechanism by which ERA improves spleen deficiency syndrome.

METHODS

Male rats were fed with Xiaochengqi decoction and subjected to irregular feeding to induce spleen deficiency syndrome. The established models were randomized into model group, high-, moderate- and low-dose ERA groups, and domperidone group. After corresponding treatment for 30 days, the content of IgA in the intestinal lavage fluid, serum IgG, and the indices of the spleen and thymus were determined. The pathological changes in the gastric mucosa was observed with HE staining, gastric mucosal blood flow was evaluated with laser Doppler rheometry, and the expression of TFF1 in the gastric mucosa and TLR4 expression in the colon tissue were detected with immunohistochemistry.

RESULTS

The rat models of spleen deficiency syndrome showed obvious abnormalities in gastric mucosal morphology, blood flow and immunological indexes. Compared with the model rats, the rats receiving ERA treatment as different doses all showed significant improvements in gastric mucosal morphology, blood flow volume, gastric mucosa trefoil factor 1 (TFF1) expression, intestinal lavage fluid IgA content, serum IgG content, indices of the spleen and thymus, and TLR4 expression in the colon TLR4 (P<0.05 or P<0.01).

CONCLUSION

ERA can inhibit gastric mucosal damage, protect and repair the damaged mucosal tissues, and improve the immune function of in rats with spleen deficiency.

Cohesin modulates transcription of estrogen-responsive genes

The cohesin complex has essential roles in cell division, DNA damage repair and gene transcription. The transcriptional function of cohesin is thought to derive from its ability to connect distant regulatory elements with gene promoters. Genome-wide binding of cohesin in breast cancer cells frequently coincides with estrogen receptor alpha (ER), leading to the hypothesis that cohesin facilitates estrogen-dependent gene transcription. We found that cohesin modulates the expression of only a subset of genes in the ER transcription program, either activating or repressing transcription depending on the gene target. Estrogen-responsive genes most significantly influenced by cohesin were enriched in pathways associated with breast cancer progression such as PI3K and ErbB1. In MCF7 breast cancer cells, cohesin depletion enhanced transcription of TFF1 and TFF2, and was associated with increased ER binding and increased interaction between TFF1 and its distal enhancer situated within TMPRSS3. In contrast, cohesin depletion reduced c-MYC mRNA and was accompanied by reduced interaction between a distal enhancer of c-MYC and its promoters. Our data indicates that cohesin is not a universal facilitator of ER-induced transcription and can even restrict enhancer-promoter communication. We propose that cohesin modulates transcription of estrogen-dependent genes to achieve appropriate directionality and amplitude of expression.

Comparison of the anti-ulcer activity between the crude and bran-processed Atractylodes lancea in the rat model of gastric ulcer induced by acetic acid

ETHNOPHARMACOLOGICAL RELEVANCE

The rhizome of Atractylodes lancea (AL, Compositae, Chinese name: Cangzhu; Japanese name: Sou-ju-tsu) has been used traditionally for the treatment of various diseases such as digestive disorders, rheumatic diseases, and influenza in China, Korea and Japan. The crude AL and AL bran-processed are both listed in the Chinese Pharmacopoeia. However, the differences between the effects of the crude and AL bran-processed on gastric ulcer were poorly understood, and the mechanisms for the treatment of gastric ulcer were not clear. This study aimed at comparing the anti-ulcer effects between the crude AL and AL processed in acetic acid induced model in rats and evaluating the mechanisms of action involved in the anti-ulcer properties of AL.

MATERIALS AND METHODS

The model of gastric ulcer was imitated by acetic acid in rats, and AL was gavaged. The serum and gastric tissues were collected. The levels of epidermal growth factor (EGF), trefoil factor2 (TFF2), tumor necrosis factor-α (TNF-α), interleukin 6, 8 (IL-6, 8) and prostaglandin E2 (PGE2) in serum and gastric tissues were determined by the double-antibody sandwich enzyme-linked immunosorbent assay (ELISA), and the mRNA expressions of EGF, TFF2, TNF-α, and IL-8 in stomach were analyzed by quantitative real-time reverse transcription polymerase chain reaction (RT-PCR). Meanwhile, histopathological changes were evaluated by hematoxylin and eosin (HE) stain. The protein expressions of EGF, TFF2, TNF-α, and IL-8 were examined by immunohistochemistry in stomach.

RESULTS

The results demonstrated that the damage of gastric tissue was obviously alleviated and the productions of TNF-α, IL-8, IL-6, and PGE2 and the mRNA expressions of TNF-α, and IL-8 were notably inhibited. Furthermore, the productions of EGF and TFF2 and the mRNA expressions of EGF and TFF2 were significantly stimulated by both crude AL and AL processed in a dose-dependent manner. Compared with the crude AL, the processed AL was more effective.

CONCLUSION

The AL processed had more satisfactory effects in treatment of gastric-ulcer than the crude AL. The anti-ulcer effects of AL could be attributed to the anti-inflammatory properties via down-regulating TNF-α, IL-8, IL-6 and PGE2 and to the gastroprotective effects via up-regulating EGF and TFF2.

Gastric-type expression signature in serrated pathway-associated colorectal tumors

Accumulating evidence has indicated that serrated pathway-associated colorectal tumors may be associated with aberrant gastric-type differentiation. Here, we investigated the immunoexpression profiles of gastric-type markers and intestinal-type markers in colorectal tumors, focusing on their relation to serrated pathway-associated tumors. Immunohistochemistry for 7 gastric-type markers (ANXA10, VSIG1, CLDN18, CTSE, TFF2, MUC5AC, and MUC6) and 2 intestinal-type markers (CDX2 and CK20) was performed in 36 normal gastric/colorectal mucosa tissues, 163 colorectal polyps, and 175 microsatellite-unstable colorectal carcinomas (MSI-H CRCs). In normal tissues, all 7 candidate gastric-type markers showed expressional specificity for normal gastric mucosa. Among the colorectal polyps, sessile serrated adenoma/polyps demonstrated the highest positive rate of ANXA10, CLDN18, MUC5AC, and MUC6 expression (87%, 35%, 61%, and 52%, respectively). Microvesicular hyperplastic polyps showed the highest frequencies of ANXA10, VSIG1, and TFF2 positivity (87%, 87%, and 67%, respectively). ANXA10 and MUC6 expression was not detected in all conventional adenomas. In MSI-H CRCs, the expression of ANXA10, TFF2, and MUC5AC was significantly associated with sporadic tumors (P < .001, P = .01, and P < .001, respectively). Moreover, all of the 7 gastric-type markers were significantly related to preferential expression in proximal colon carcinomas among MSI-H CRCs. CDX2 and CK20 expression was retained in all colorectal polyps, whereas there were significantly high frequencies of CDX2 loss (28%) and CK20 loss (29%) in sporadic tumors among MSI-H CRCs. In conclusion, the early gain of gastric differentiation and late loss of intestinal differentiation are immunophenotypic features in the serrated pathway to colorectal carcinoma.

Trefoil factors (TFFs) are increased in bronchioalveolar lavage fluid from patients with chronic obstructive lung disease (COPD)

Trefoil factors (TFFs) 1, 2 and 3 are small polypeptides that are co-secreted with mucin throughout the body. They are up-regulated in cancer and inflammatory processes in the gastrointestinal system, where they are proposed to be involved in tissue regeneration, proliferation and protection. Our aim was to explore their presence in pulmonary secretions and to investigate whether they are up-regulated in pulmonary diseases characterized by mucin hypersecretion. Bronchioalveolar lavage fluid was obtained from 92 individuals referred to bronchoscopy. The patients were grouped according to diagnosis and pulmonary function. The concentrations of TFF1, TFF2 and TFF3 were measured by ELISA. All three peptides were detected in bronchioalveolar lavage fluid. Patients with chronic obstructive pulmonary disease had concentrations two to three times above the levels in the healthy reference group, and patients with pulmonary malignancies had concentrations of TFF1 and TFF2 three times that of the reference group. The results suggest that TFFs are involved in tissue regeneration, proliferation and protection in lung diseases.

Folding mechanisms of Trefoil Knot proteins studied by molecular dynamics simulations and Go-model

Most proteins need to avoid the complex topologies when folding into the native structures, but some proteins with nontrivial topologies have been found in nature. Here we used protein unfolding simulations under high temperature and all-atom Gō-model to investigate the folding mechanisms for two trefoil knot proteins. Results show that, the contacts in β-sheet are important to the formation of knot protein, and if these contacts disappeared, the knot protein would be easy to untie. In the Gō-model simulations, the folding processes of the two knot proteins are similar. The compact structures of the two knot proteins with the native contacts in β-sheet are formed in transition state, and the intermediate state has loose C-terminal. This model also reveals the detailed folding mechanisms for the two proteins.

The stem cell organisation, and the proliferative and gene expression profile of Barrett's epithelium, replicates pyloric-type gastric glands

OBJECTIVE

Barrett's oesophagus shows appearances described as 'intestinal metaplasia', in structures called 'crypts' but do not typically display crypt architecture. Here, we investigate their relationship to gastric glands.

METHODS

Cell proliferation and migration within Barrett's glands was assessed by Ki67 and iododeoxyuridine (IdU) labelling. Expression of mucin core proteins (MUC), trefoil family factor (TFF) peptides and LGR5 mRNA was determined by immunohistochemistry or by in situ hybridisation, and clonality was elucidated using mitochondrial DNA (mtDNA) mutations combined with mucin histochemistry.

RESULTS

Proliferation predominantly occurs in the middle of Barrett's glands, diminishing towards the surface and the base: IdU dynamics demonstrate bidirectional migration, similar to gastric glands. Distribution of MUC5AC, TFF1, MUC6 and TFF2 in Barrett's mirrors pyloric glands and is preserved in Barrett's dysplasia. MUC2-positive goblet cells are localised above the neck in Barrett's glands, and TFF3 is concentrated in the same region. LGR5 mRNA is detected in the middle of Barrett's glands suggesting a stem cell niche in this locale, similar to that in the gastric pylorus, and distinct from gastric intestinal metaplasia. Gastric and intestinal cell lineages within Barrett's glands are clonal, indicating derivation from a single stem cell.

CONCLUSIONS

Barrett's shows the proliferative and stem cell architecture, and pattern of gene expression of pyloric gastric glands, maintained by stem cells showing gastric and intestinal differentiation: neutral drift may suggest that intestinal differentiation advances with time, a concept critical for the understanding of the origin and development of Barrett's oesophagus.

Dynamic estrogen receptor interactomes control estrogen-responsive trefoil Factor (TFF) locus cell-specific activities

Estradiol signaling is ideally suited for analyzing the molecular and functional linkages between the different layers of information directing transcriptional regulations: the DNA sequence, chromatin modifications, and the spatial organization of the genome. Hence, the estrogen receptor (ER) can bind at a distance from its target genes and engages timely and spatially coordinated processes to regulate their expression. In the context of the coordinated regulation of colinear genes, identifying which ER binding sites (ERBSs) regulate a given gene still remains a challenge. Here, we investigated the coordination of such regulatory events at a 2-Mb genomic locus containing the estrogen-sensitive trefoil factor (TFF) cluster of genes in breast cancer cells. We demonstrate that this locus exhibits a hormone- and cohesin-dependent reduction in the plasticity of its three-dimensional organization that allows multiple ERBSs to be dynamically brought to the vicinity of estrogen-sensitive genes. Additionally, by using triplex-forming oligonucleotides, we could precisely document the functional links between ER engagement at given ERBSs and the regulation of particular genes. Hence, our data provide evidence of a formerly suggested cooperation of enhancers toward gene regulation and also show that redundancy between ERBSs can occur.

Piezo1 is as a novel trefoil factor family 1 binding protein that promotes gastric cancer cell mobility in vitro

BACKGROUND

Trefoil factor family 1 (TFF1) is a member of the TFF-domain peptide family involved in epithelial restitution and cell motility. Recently, we screened Piezo1 as a candidate TFF1-binding protein.

AIM

We aimed to confirm Piezo1 as a novel TFF1 binding protein and to assess the role of this interaction in mediating gastric cancer cell mobility.

METHODS

This interaction was confirmed by co-immunoprecipitation and co-localisation of TFF1 and Piezo1 in GES-1 cells. We used stable RNA interference to knockdown Piezo1 protein expression and restored the expression of TFF1 in the gastric cancer cell lines SGC-7901 and BGC-823. Cell motility was evaluated using invasion assay and migration assay in vitro. The expression levels of the integrin subunits β1, β5, α1 as well as the expression of β-catenin and E-cadherin were detected by Western blot.

RESULTS

We demonstrate that TFF1, but not TFF2 or TFF3, bind to and co-localize with Piezo1 in the cytoplasm in vitro. TFF1 interacts with the C-terminal portion of the Piezo1 protein. Wound healing and trans-well assays demonstrated that the restored expression of TFF1 promoted cell mobility in gastric cancer cells, and this effect was attenuated by the knockdown of Piezo1. Western blots demonstrated the decreased expression of integrin β1 in Piezo1-knockdown cells.

CONCLUSIONS

Our data demonstrate that Piezo1 is a novel TFF1 binding protein that is important for TFF1-mediated cell migration and suggest that this interaction may be a therapeutic target in the invasion and metastasis of gastric cancer.

Trefoil factors in inflammatory bowel disease

Inflammatory bowel disease (IBD), which comprises ulcerative colitis and Crohn’s disease, is characterized by inflammation of the gastrointestinal tract. The trefoil factors 1, 2, and 3 (TFF1-3) are a family of peptides that play important roles in the protection and repair of epithelial surfaces, including the gastrointestinal tract. TFFs may be involved in IBD pathogenesis and are a potential treatment option. In the present review, we describe the TFF family and their potential role in IBD by summarizing the current knowledge of their expression, possible function and pharmacological role in IBD.

Long-term intake of pea fiber affects colonic barrier function, bacterial and transcriptional profile in pig model

The objective of this study was to investigate the effect of long-term intake of pea fiber (PF) on colonic health and the underlying mechanism. Fifty weaned piglets were randomly allocated into 2 groups receiving control and fibrous diet with inclusion of PF from weaning to Day 160 postweaning, with 5 pens in each group and 5 pigs in each pen. Compared with control diet, long-term intake of PF diet induced deeper crypt and increased colonic barrier-related protein expression of mucin and sIgA. As indicated by the increased lactobacillus content, pigs fed PF diet had a stimulating effect on bacterial fermentation in the colon, thus a higher concentration of colonic total short chain fatty acid and acetic acid were observed. DNA microarray results suggested that feeding PF diet inhibited 77% of genes (40 downregulated and 12 upregulated genes) related to colonic cancer, immune response, and lipid metabolism, involving in signal pathway such as intestinal immune network for IgA production, peroxisome proliferator-activated receptor signaling pathway and nutrient metabolism-related pathways. Collectively, our results suggested that long-term intake of PF would improve colonic function via altering colonic barriers, colonic immune and metabolism-related protein or gene expressions.

[The expression and significance of trefoil factor 3 and SDF-1/CXCR4 biological axis in papillary thyroid carcinoma]

OBJECTIVE

To study the expression of trefoil factor 3 (TFF3)with stromal cell-derived factor (SDF-1) and its receptor (CXCR4) in papillary thyroid carcinoma(PTC), and investigate the function of TFF3, SDF-1/ CXCR4 and the relationship among them during the tumor genesis,development and outcome of PTC.

METHOD

Detecting the expression of TFF3 and SDF-1/CXCR4 by immunohistochemical method (SP) in 92 cases of PTC and para-carcinoma tissue. Semiquantitative analysis of the results of immunohistochemistry was conducted by image analysis software.

RESULT

(1) TFF3 protein was expressed in the cytoplasm of cancer cells,while TFF3 was negative or weakly positive in follicular cells of para-carcinoma tissue. The positive expression rate of TFF3 was 92.39%, of which the strong positive rate of clinical stage III-IV accounted for 71.79% (42/59) and that of clinical stage I-II was 33.33% (11/33) (P < 0.01). The positive rate of TFF3 was significantly higher in the cases with lymph node metastasis than those without lymph node metastasis (100.00% vs 86.27%, P < 0.05). The AOD value of TFF3 was higher in PTC than in para-carcinoma tissue, that in cases with lymph node metastasis was higher than those without lymph node metastasis, and that in stage III-IV was higher than those in I-II (P < 0.05 or P < 0.05). (2) There was high expression of SDF-1 in the cytoplasm of malignant tissues. The para-carcinoma tissue was weakly positive or negative to SDF 1 and metastatic lymph nodes was weakly positive to SDF 1. The positive rates and AOD values of SDF-1 protein were similar to those of TFF3 in PTC,that is to say the positive rate and AOD values were higher in PTC than in para-carcinoma tissue, those in cases with lymph node metastasis were higher than those without lymph node metastasis, those in stage III-IV were higher than those in I-II, and those in patients older than 45 years old was obviously higher than those in patients under 45 years old (P < 0.05 or P < 0.01); CXCR4 was also mainly expressed in cytoplasm with few expression in nuclei, while negative or weakly positive in para-carcinoma. The positive rate and AOD values of CXCR4 in PTC were similar to SDF-1, meaning that they were higher in PTC than in para-carcinoma tissue and associated with the clinical stage, lymph node metastasis and age (P < 0.05 or P < 0.01). (3) There was positive relationship between TFF3 and SDF-1 as well as between SDF-1 and CXCR4 in PTC (r = 0.971, P < 0.01).

CONCLUSION

The high expression of TFF3, SDF-1 and CXCR4 in PTC are correlated with carcinogenesis and progression, and may play a significant role in evaluating the malignancy degree and progression of PTC.

Altered innate defenses in the neonatal gastrointestinal tract in response to colonization by neuropathogenic Escherichia coli

Two-day-old (P2), but not 9-day-old (P9), rat pups are susceptible to systemic infection following gastrointestinal colonization by Escherichia coli K1. Age dependency reflects the capacity of colonizing K1 to translocate from gastrointestinal (GI) tract to blood. A complex GI microbiota developed by P2, showed little variation over P2 to P9, and did not prevent stable K1 colonization. Substantial developmental expression was observed over P2 to P9, including upregulation of genes encoding components of the small intestinal (α-defensins Defa24 and Defa-rs1) and colonic (trefoil factor Tff2) mucus barrier. K1 colonization modulated expression of these peptides: developmental expression of Tff2 was dysregulated in P2 tissues and was accompanied by a decrease in mucin Muc2. Conversely, α-defensin genes were upregulated in P9 tissues. We propose that incomplete development of the mucus barrier during early neonatal life and the capacity of colonizing K1 to interfere with mucus barrier maturation provide opportunities for neuropathogen translocation into the bloodstream.

Trefoil factor 2 expression and its significance as a predictor of severity of sepsis in children

Intestinal injury significantly contributes to critical illness, sepsis and multiorgan failure. TFF2 (Trefoil Factor 2) is expressed and secreted preferentially by gastric mucous neck cells. TFF2 gene expression is promptly increased after gut injury, and its expression profile broadens to include the regenerative epithelia of virtually the entire gastrointestinal tract. The first objective of our study was an analysis of TFF2 levels dynamics in patients with Systemic Inflammatory Response Syndrome (SIRS) or septic condition during a 5-day period after admission. The second objective was to determine optimal cut-off value and quantify diagnostic characteristics of TFF2 between controls and patients with various septic states. The study included 57 children aged 0-19 years, with expected or proven SIRS and septic condition. The degree of severity was evaluated according to PELOD Score (Pediatric Logistic Organ Dysfunction). Blood samples to determine levels of TFF2 factor were taken during the time patient met the criteria of SIRS or sepsis. Control group samples to determine the serum levels of TFF2 were taken from patients undergoing elective surgery. Analysis of TFF2 levels dynamics revealed that TFF2 levels kept steady state during the 5-day period. Significantly higher levels of TFF2 were in patients with Multiple Organ Dysfunction Syndrome (MODS). The difference was noticed also in ROC analysis.

Trefoil factor family member 2 (Tff2) KO mice are protected from high-fat diet-induced obesity

INTRODUCTION

Trefoil factor family member 2 (Tff2) is a small gut peptide, mainly known for its protective and healing functions. As previously demonstrated, high-fat (HF) feeding can rapidly and specifically modulate Tff2 transcription in key tissues of mice, including the duodenum and mesenteric adipose tissue, therefore suggesting a novel role for this gene in energy balance.

DESIGN AND METHODS

To explore whether and how Tff2 can influence feeding behavior and energy metabolism, Tff2 knock-out (KO) mice were challenged with HF diet for 12 weeks, hence food and energy intakes, body composition, as well as energy excretion and serum lipid and hormonal levels were analyzed. Finally, energy efficiency was estimated.

RESULTS

Tff2 KO mice showed a greater appetite and higher energy intake compared to wild-type (WT). Consistently, they presented lower levels of serum leptin, and increased transcription of agouti-related protein (Agrp) in the hypothalamus. Though energy and triglyceride fecal excretion were augmented in Tff2 KO mice, digestible energy intake was superior. However, KO mice were finally protected from HF diet-induced obesity, and accumulated less weight and fat depots than WT animals, while keeping a normal lean mass. Energy efficiency was lower in HF-KO mice, while energy expenditure and locomotor activity were globally increased.

CONCLUSIONS

The present work demonstrates previously unsuspected roles for Tff2 and suggests it to be a mastermind in the control of energy balance and a promising therapeutic target for obesity.

A variant form of the human deleted in malignant brain tumor 1 (DMBT1) gene shows increased expression in inflammatory bowel diseases and interacts with dimeric trefoil factor 3 (TFF3)

The protein deleted in malignant brain tumors (DMBT1) and the trefoil factor (TFF) proteins have all been proposed to have roles in epithelial cell growth and cell differentiation and shown to be up regulated in inflammatory bowel diseases. A panel of monoclonal antibodies was raised against human DMBT1^gp340. Analysis of lung washings and colon tissue extracts by Western blotting in the unreduced state, two antibodies (Hyb213-1 and Hyb213-6) reacted with a double band of 290 kDa in lung lavage. Hyb213-6, in addition, reacted against a double band of 270 kDa in colon extract while Hyb213-1 showed no reaction. Hyb213-6 showed strong cytoplasmic staining in epithelial cells of both the small and large intestine whereas no staining was seen with Hyb213-1. The number of DMBT1^gp340 positive epithelial cells, stained with Hyb213-6, was significantly up regulated in inflammatory colon tissue sections from patients with ulcerative colitis (p<0.0001) and Crohn’s disease (p = 0.006) compared to normal colon tissue. Immunohistochemical analysis of trefoil factor TFF1, 2 and 3 showed that TFF1 and 3 localized to goblet cells in both normal colon tissue and in tissue from patients with ulcerative colitis or Crohn’s disease. No staining for TFF2 was seen in goblet cells in normal colon tissue whereas the majority of tissue sections in ulcerative colitis and Crohn’s disease showed sparse and scattered TFF2 positive goblet cells. DMBT1 and TFF proteins did therefore not co-localize in the same cells but localized in adjacent cells in the colon. The interaction between DMBT1^gp340 and trefoil TFFs proteins was investigated using an ELISA assay. DMBT1^gp340 bound to solid-phase bound recombinant dimeric TFF3 in a calcium dependent manner (p<0.0001) but did not bind to recombinant forms of monomeric TFF3, TFF2 or glycosylated TFF2. This implies a role for DMBT1 and TFF3 together in inflammatory bowel disease.

Recombinant adenovirus-mediated intestinal trefoil factor gene therapy for burn-induced intestinal mucosal injury

Intestinal trefoil factor (ITF) is a small polypeptide with potential medical values whose main pharmacological effects are to alleviate gastrointestinal mucosal injury caused by various injury factors and promote the repair of damaged mucosa. However, its low yield limits its application. The purpose of our study was to construct a recombinant adenoviral vector containing the hITF gene and observe the therapeutic effect of burn-induced intestinal mucosal injury using in vitro and in vivo analysis. First, a recombinant shuttle plasmid was constructed by ligating a pAdTrack-CMV vector with a full-length hITF gene containing a signal peptide and the mature peptide, followed by the recombinant Ad-hITF adenovirus vector after linearization and homologous recombination with the backbone plasmid in the competent BJ5183 strain. Second, the hITF expression level was detected using reverse transcription polymerase chain reaction and western blotting after Ad-hITF infection of colon cancer HT-29 cells. The recombinant adenovirus significantly promoted cell migration in an in vitro wounding model. Finally, we confirmed that the recombinant adenovirus could significantly expedite the healing of intestinal mucosal injury after establishing a mouse model in which severe burns were stimulated and the recombinant adenovirus was delivered by intragastric injection. In summary, we constructed a recombinant adenoviral vector containing the hITF gene and confirmed its role in promoting repair of the intestinal mucosa. Our study provides a novel way to treat burn-induced intestinal mucosal injury.

Trefoil factor 2 promotes cell proliferation in pancreatic β-cells through CXCR-4-mediated ERK1/2 phosphorylation

Decreased β-cell mass is a hallmark of type 2 diabetes, and therapeutic approaches to increase the pancreatic β-cell mass have been expected. In recent years, gastrointestinal incretin peptides have been shown to exert a cell-proliferative effect in pancreatic β-cells. Trefoil factor 2 (TFF2), which is predominantly expressed in the surface epithelium of the stomach, plays a role in antiapoptosis, migration, and proliferation. The TFF family is expressed in pancreatic β-cells, whereas the role of TFF2 in pancreatic β-cells has been obscure. In this study, we investigated the mechanism by which TFF2 enhances pancreatic β-cell proliferation. The effects of TFF2 on cell proliferation were evaluated in INS-1 cells, MIN6 cells, and mouse islets using an adenovirus vector containing TFF2 or a recombinant TFF2 peptide. The forced expression of TFF2 led to an increase in bromodeoxyuridine (BrdU) incorporation in both INS-1 cells and islets, without any alteration in insulin secretion. TFF2 significantly increased the mRNA expression of cyclin A2, D1, D2, D3, and E1 in islets. TFF2 peptide increased ERK1/2 phosphorylation and BrdU incorporation in MIN6 cells. A MAPK kinase inhibitor (U0126) abrogated the TFF2 peptide-mediated proliferation of MIN6 cells. A CX-chemokine receptor-4 antagonist also prevented the TFF2 peptide-mediated increase in ERK1/2 phosphorylation and BrdU incorporation in MIN6 cells. These results indicated that TFF2 is involved in β-cell proliferation at least partially via CX-chemokine receptor-4-mediated ERK1/2 phosphorylation, suggesting TFF2 may be a novel target for inducing β-cell proliferation.

Proteomic profiling of paraffin-embedded samples identifies metaplasia-specific and early-stage gastric cancer biomarkers

Early diagnosis and curative resection are the predominant factors associated with increased survival in patients with gastric cancer. However, most gastric cancer cases are still diagnosed at later stages. Since most pathologic specimens are archived as FFPE samples, the ability to use them to generate expression profiles can greatly improve cancer biomarker discovery. We sought to uncover new biomarkers for stomach preneoplastic metaplasias and neoplastic lesions by generating proteome profiles using FFPE samples. We combined peptide isoelectric focusing and liquid chromatography-tandem mass spectrometry analysis to generate proteomic profiles from FFPE samples of intestinal-type gastric cancer, metaplasia, and normal mucosa. The expression patterns of selected proteins were analyzed by immunostaining first in single tissue sections from normal stomach, metaplasia, and gastric cancer and later in larger tissue array cohorts. We detected 60 proteins up-regulated and 87 proteins down-regulated during the progression from normal mucosa to metaplasia to gastric cancer. Two of the up-regulated proteins, LTF and DMBT1, were validated as specific markers for spasmolytic polypeptide-expressing metaplasia and intestinal metaplasia, respectively. In cancers, significantly lower levels of DMBT1 or LTF correlated with more advanced disease and worse prognosis. Thus, proteomic profiling using FFPE samples has led to the identification of two novel markers for stomach metaplasias and gastric cancer prognosis.

Prohibitins are involved in protease-activated receptor 1-mediated platelet aggregation

BACKGROUND

Prohibitins (PHBs), comprising the two homologous members PHB1 and PHB2, are ubiquitously expressed and highly conserved. The membrane PHBs have been reported to be involved in typhoid fever, obesity, and cancer metastasis. Proteomic studies have revealed the presence of PHBs in human platelets, but the roles of PHBs during platelet aggregation are unknown.

OBJECTIVES

To investigate the role of PHBs in platelet aggregation.

METHODS AND RESULTS

PHB1 and PHB2 were detected on the surfaces of human platelets by flow cytometry and confocal microscopy. The PHBs were distributed in lipid rafts, as determined by sucrose density centrifugation. In addition, the PHBs were associated with protease-activated receptor 1 (PAR1), as determined by Bm-TFF2 (a PAR1 agonist)-affinity chromatography, coimmunoprecipitation, and confocal microscopy. The platelet aggregation, α(IIb) β(3) activation, granular secretion and calcium mobilization stimulated by low concentrations of thrombin (0.05 U mL(-1)) or PAR1-activating peptide (PAR1-AP) (20 μm) were reduced or abolished as a result of the blockade of PHBs by anti-PHB antibodies or their Fab fragments; however, the same results were not obtained with induction by high concentrations of thrombin (0.6 U mL(-1)) or protease-activated receptor 4-activating peptide (300 μm). The calcium mobilization in MEG-01 megakaryocytes stimulated by PAR1-AP was significantly suppressed by PHB depletion with RNA interference against PHB1 and PHB2.

CONCLUSIONS

PHBs are localized on the human platelet membrane and are involved in PAR1-mediated platelet aggregation. Until recently, PHBs were unknown as regulators of PAR1 signaling, and they may be effective targets for antiplatelet therapy.

Bile acid and inflammation activate gastric cardia stem cells in a mouse model of Barrett-like metaplasia

Esophageal adenocarcinoma (EAC) arises from Barrett esophagus (BE), intestinal-like columnar metaplasia linked to reflux esophagitis. In a transgenic mouse model of BE, esophageal overexpression of interleukin-1β phenocopies human pathology with evolution of esophagitis, Barrett-like metaplasia and EAC. Histopathology and gene signatures closely resembled human BE, with upregulation of TFF2, Bmp4, Cdx2, Notch1, and IL-6. The development of BE and EAC was accelerated by exposure to bile acids and/or nitrosamines, and inhibited by IL-6 deficiency. Lgr5(+) gastric cardia stem cells present in BE were able to lineage trace the early BE lesion. Our data suggest that BE and EAC arise from gastric progenitors due to a tumor-promoting IL-1β-IL-6 signaling cascade and Dll1-dependent Notch signaling.

Stem cells, self-renewal and cancer of the gastric epithelium

The gastric mucosa and its glands show continuous bidirectional self-renewal via differentiation from stem and progenitor cells. Here, two types of gastric units, i.e., fundic and antral units, form delicate homeostatic systems. This review focuses on recent developments concerning the different types of gastric stem cells, the central function of parietal cells as organizing centres of fundic units, the stepwise differentiation of zymogenic cells via trans-differentiation of mucous neck cells, and unexpected differences between fundic and antral surface mucous cells. Within the last years, the central role of Sonic hedgehog (Shh) for correct self-renewal of fundic units has become much clearer. Furthermore, also the knowledge concerning the genesis of gastric cancer increased substantially. Here, chronic inflammation leads to dysregulated differentiation processes and finally to cancer. Remarkable progress has been made particularly concerning the genesis of two metaplastic cell lineages, i.e., the TFF2/spasmolytic polypeptide expressing metaplasia (SPEM) and intestinal metaplasia, which both arise in intestinal-type cancers in fundic units by dysregulated trans-differentiation of the zymogenic cell lineage. Additionally, Shh has been recognized as a target for inflammatory processes and an important player for innate immunity processes. Thus, stem cells, self-renewal, and gastric cancer are intimately linked.

Pathophysiological investigation of the gastric surface mucous gel layer of patients with Helicobacter pylori infection by using immunoassays for trefoil factor family 2 and gastric gland mucous cell-type mucin in gastric juice

BACKGROUND

The trefoil factor family (TFF) 2 protein is produced by gastric gland mucous cells (GMCs), and the secreted TFF2 shares a mucosal barrier function with GMC-type mucin. Recently, we presented an enzyme-linked immunosorbent assay (ELISA) method for measurement of GMC-type mucin in the gastric juice.

AIMS

We aimed to develop an ELISA for TFF2 and to assess pathophysiological changes in the gastric surface mucous gel layer (SMGL) of patients with Helicobacter pylori infection.

METHODS

The distribution of TFF2 and GMC-type mucin in the SMGL was immunohistochemically determined. The ELISA for TFF2 was based on a polyclonal goat antibody. Recombinant TFF2 was employed to prepare the calibrators. TFF2 and GMC-type mucin in the gastric juice in healthy individuals (n = 33) and patients with gastritis (n = 37), gastric ulcer (n = 16), and duodenal ulcer (n = 10) were assayed using ELISA.

RESULTS

TFF2 and GMC-type mucin were immunohistochemically co-localized in the gastric SMGL and GMCs. The TFF2 levels in the patients were significantly higher than those in the healthy individuals. Further, the TFF2 levels in the H. pylori-positive patients were significantly higher than those in the H. pylori-negative patients, and decreased after the eradication of the infection. GMC-type mucin levels showed a tendency similar to that of TFF2 levels.

CONCLUSIONS

The upregulation of TFF2 and GMC-type mucin secretion may reflect the response of the gastric mucosa to H. pylori-induced injuries. TFF2 and GMC-type mucin secreted into the SMGL may protect the gastric mucosa against H. pylori.

[Effects of intestinal trefoil factor on Toll-like receptors 2 and 4 expression in intestinal tissue in young rats with endotoxemia]

OBJECTIVE

To study the effects of intestinal trefoil factor (ITF) on Toll-like receptors (TLR) 2 and 4 expression in intestinal tissue and on intestinal injury in young rats with endotoxemia.

METHODS

A total of 24 10-day-old Wistar rat pups were equally randomly divided into three groups: a control group, intraperitoneally injected with normal saline 1 mL/kg; an endotoxemia group, intraperitoneally injected with lipopolysaccharide (LPS) 5 mg/kg and an ITF group,intraperitoneally injected with rITF 0.1 mL/each plus LPS 5 mg/kg. Rats were sacrificed 3 h after injection. A segment of distal ileum was dissected for pathologic examinations under an optical microscope (hematoxylin-eosin staning). The mRNA expressions of TLR2 and TLR4 were detected by reverse transcriptase polymerase chain reaction (RT-PCR).

RESULTS

The structure of the small intestine remained normal in the control group. Edema of interstitial substance and epithelium were observed in both LPS and ITF groups, whereas such changes were significantly lower in the ITF group than in the LPS group. The ITF group had significantly higher TLR2 mRNA expression than the NS and LPS groups (P<0.01), whereas the mRNA expression of TLR4 in the ITF group was significantly lower than in the NS and LPS groups (both P<0.01).

CONCLUSIONS

ITF can alleviate intestinal injury in young rats with endotoxemia, which may be related to the down-regulation of TLR4 mRNA expression.

[Effects of intestinal trefoil factor combined with mucin on immune function of burn serum treated intestinal epithelial cells]

OBJECTIVE

To observe the effect of intestinal trefoil factor (ITF) combined with mucin on immune function of intestinal epithelial cells (IEC) after being treated with burn rat serum.

METHODS

The rat IEC-6 cell lines were divided into control group (C, cultured in DEME medium containing 10% calf serum), burn control group (BC, cultured in DEME medium containing 10% burn rat serum), burn serum + ITF group (B + I, cultured in DEME medium containing 10% burn rat serum and 25 microg/mL ITF), burn serum + mucin group (B + M, cultured in DEME medium containing 10% burn rat serum and 250 microg/mL mucin), and burn serum + ITF + mucin group (B + I + M, cultured in DEME medium containing 10% burn rat serum, 25 microg/mL ITF, and 250 microg/mL mucin) according to the random number table. Meanwhile, 200 microL suspension of E. coli with density of 1 x 10(8) CFU/mL was added to each culture. At post culture minute (PCM) 15, 30 and post culture hour (PCH) 1, 2, 3, the number of bacteria adherent to IEC-6 was counted after Wright-Giemsa staining, and cell survival rate was calculated after trypan blue staining, with 20 samples in each group at each time point. (2) Other samples of IEC-6 cells without addition of E. coli were divided into BC, B + I, B + M, and B + I + M groups with the same treatment as above. The supernatant contents of IL-6, IL-8, and TNF-alpha were determined by radioimmunoassay at PCH 3, 6, 12, 24, 48, with 6 samples in each group at each time point. Data were processed with t test.

RESULTS

(1) Compared with that in C group, count of adherent bacteria to IEC-6 in BC group at each time point was significantly increased (with t values from 2.947 to 8.149, P values all below 0.01). Compared with those in BC group, the counts in B + I, B + M, B + I + M groups at the major time points were significantly decreased (with t values from -4.733 to -2.180, P < 0.05 or P < 0.01). (2) Compared with that in C group, cell survival rate in BC group at each time point was obviously lowered (with t values from -4.126 to -2.363, P values all below 0.05). Cell survival rates in B + I and B + M groups at some time points were significantly elevated as compared with those in BC group (with t values from 2.120 to 3.423, P < 0.05 or P < 0.01). Cell survival rate in B + I + M group at PCM 15 and PCH 3 was respectively (96.7 +/- 2.4)% and (84.0 +/- 6.7)%, which was respectively higher than that in B + I and B + M groups [(94.5 +/- 3.1)%, t = 2.507, P < 0.05; (77.1 +/- 8.2)%, t = 2.934, P < 0.01]. (3) The contents of TNF-alpha in supernatant of B + I + M group at PCH 6, 12, 24, 48 were significantly lower than those in the other 3 groups (with t values from -6. 914 to -2.889, P < 0.05 or P < 0.01). The contents of IL-6 in supernatant of B + I + M group at some time points were significantly lower than those in the other 3 groups (with t values from -7. 657 to -2.580, P < 0.05 or P < 0.01). The contents of IL-8 in supernatant of B + I + M group at PCH 6, 12, 24, 48 were significantly lower than those in BC and B + M groups (with t values from - 8.802 to - 3.640, P values all below 0.01), and those in B + I + M group at PCH 12, 24 were lower than those in B + I group (with t value respectively -2.786, -2.740, P value all below 0.05).

CONCLUSIONS

ITF can maintain immune function and homeostasis of IEC, prevent bacterial adherence, decrease cell death rate, and reduce release of inflammatory mediators. The effect can be strengthened with addition of mucin.

[Effects of intestinal trefoil factor combined with mucin on ability of proliferation and migration of intestinal epithelial cells after being treated by rat burn serum]

OBJECTIVE

To observe the effect of intestinal trefoil factor (ITF) combined with mucin on the ability of proliferation and migration of intestinal epithelial cells (IEC) after being treated by burn rat serum.

METHODS

The rat IEC-6 cell lines were subcultured and divided into control group (C, cultured with DMEM medium containing 10% calf serum), burn serum group (BS, cultured with DMEM medium containing 10% burn rat serum), burn serum + ITF group (B + I, cultured with DMEM medium containing 10% burn rat serum and 25 microg/mL ITF), burn serum + mucin group (B + M, cultured with DMEM medium containing 10% burn rat serum and 250 microg/mL mucin), and burn serum + ITF + mucin group (B + I + M, cultured with DMEM medium containing 10% burn rat serum, 25 microg/mL ITF, and 250 microg/mL mucin) according to the random number table. Cells were counted on post culture day (PCD) 0, 1, 2, 3, 4, reflecting cell proliferation ability. Cell migration distance was measured at post scratch hour (PSH) 12, 24, 36, 48, 72. Then, cells of each group were placed in upper compartment of Transwell chamber while the corresponding medium was respectively added into lower compartment of Transwell chamber. Cells in lower compartment of Transwell chamber were counted at post culture hour (PCH) 4, 6, 8, 10, 12, reflecting cytomorphosis ability. Data were processed with t test.

RESULTS

(1) Cell proliferation ability. The cell numbers in BS group on PCD 0, 1, 2, 3, 4 were significantly less than those in C group (with t values from -16.569 to -2.613, P < 0.05 or P < 0.01). The cell number showed no statistical difference between B + I and BS groups, and between B + M and BS groups at each time point (with t values respectively from 0.037 to 0.740 and 0.116 to 0.429, P values all above 0.05). The cell number in B + I + M group on PCD 2 was respectively larger than that in BS group (t = 6.484, P < 0.01) and B + I group ( t = 3.838, P < 0.01). (2) Cell migration distance in BS group at PSH 12, 24, 36, 48, 72 was significantly shorter than that in C group (with t values from -37.594 to -6.727, P values all below 0.01). There was no obvious difference in cell migration distance between BS and B + M groups at each time point (with t values from 0.055 to 0.589, P values all above 0.05). Cell migration distance in B + I group at PSH 12, 24, 36 was respectively (47 +/- 6), (126 +/- 13), (170 +/- 11) microm, all longer than those in BS group [(42 +/- 7), (98 +/- 14), (154 +/- 22) microm, with t values from 2.230 to 4.817, P < 0.05 or P < 0.01]. Cell migration distance in BS group at PSH 12, 24, 36, 48, 72 and B + I group at PSH 12, 24, 36, 48 was respectively shorter than that in B + I + M group (with t values respectively from 2.982 to 7.390 and 2.707 to 2.918, P < 0.05 or P < 0.01). (3) Cytomorphosis ability. Compared with those of C group, cell counts in lower compartment of BS group at PCH 4, 6, 8, 10, 12 were significantly decreased (with t values from -23.965 to -6.436, P values all below 0.01). Cell count in lower compartment of BS group at PCH 4, 6, 8, 10, 12 was respectively less than that of B + I group (with t values from 3.650 to 10.028, P values all below 0.01) and similar to that of B + M group (with t values from 0.199 to 0.797, P values all above 0.05). Cell counts in lower compartment of B + I + M group at PCH 4, 6, 8, 10, 12 were significantly larger than those of BS group (with t values from 4.313 to 15.100, P values all below 0.01). Cell count in lower compartment of B + I + M group at PCH 10 (328 +/- 47) and PCH 12 (465 +/- 37) was respectively larger than that in B + I group (277 +/- 25, 353 +/- 34, with t value respectively 3.051, 6.945, P values all below 0.01).

CONCLUSIONS

ITF can improve cytomorphosis ability for promoting cell migration with limited effect on cell proliferation, which can be enhanced with addition of mucin. The main mechanism of ITF in maintaining intestinal mucosal barrier may be attributed to acceleration of cell migration.

Evolution of trefoil factor(s): genetic and spatio-temporal expression of trefoil factor 2 in the chicken (Gallus gallus domesticus)

Trefoil factors are essential healing initiators participating in mucosal reconstitution and tissue morphogenesis, especially on the surfaces of the gastrointestinal tract. This family has been cloned and characterized predominantly from mammals and amphibians. Avian species ingest stone and grit to help digest food, which may expose their gut to severe physical conditions. To further the understanding of the function of the TFF gene family across species, we undertook this research to clone, sequence, and characterize the spatio-temporal expression patterns of chicken TFF2 (ChTFF2) cDNA. Bioinformatics analysis of the promoter region and deduced amino acid sequence demonstrated that ChTFF2 contained unique characteristics; specifically the chicken promoter has multiple start sites and the protein contains a series of Lys-Lys-Val repeats. Unlike mammals, where TFF2 is detected primarily in the stomach, and occasionally in the proximal duodenum, chicken TFF2 transcripts are found throughout the gastrointestinal tract, with major expression sites in the glandular and muscular stomach as well as evident expression in the colon, small intestine, cecal tonsil and crop. Temporal analysis of intestinal ChTFF2 transcripts by quantitative RT-PCR showed high levels in embryos and a trend of constant expression during embryonic and post-hatch development, with a reduction occurring around hatch. Phylogenetic analysis highlighted the conservation of TFF proteins and functional divergence of trefoil domains, which suggest a transitional role in the bird during evolution.

A chimeric peptide of intestinal trefoil factor containing cholesteryl ester transfer protein B cell epitope significantly inhibits atherosclerosis in rabbits after oral administration

Vaccination against cholesteryl ester transfer protein (CETP) is proven to be effective for inhibiting atherosclerosis in animal models. In this study, the proteases-resistant intestinal trefoil factor (TFF3) was used as a molecular vehicle to construct chimeric TFF3 (cTFF3) containing CETP B cell epitope and tetanus toxin helper T cell epitope. It was found that cTFF3 still preserved a trefoil structure, and can resist proteases digestion in vitro. After oral immunization with cTFF3, the CETP-specific IgA and IgG could be found in intestine lavage fluid and serum, and the anti-CETP antibodies could inhibit partial CETP activity to increase high-density lipoprotein cholesterol, decrease low-density lipoprotein cholesterol, and inhibit atherosclerosis in animals. Therefore, TFF3 is a potential molecular vehicle for developing oral peptide vaccines. Our research highlights a novel strategy for developing oral peptide vaccines in the future.

[Expression and identification of Bm-TFF2 in Pichia pastoris]

Bm-TFF2, an amphibian trefoil factor, which is isolated from skin secretions of frog Bombina maxima, has much stronger biological activities than human TFFs. In the present study, Bm-TFF2 gene was amplified by polymerase chain reaction (PCR) from its cDNA and cloned into Pichia pastoris expression vector pPIC9K containing AOX1 promoter and alpha -factor leader sequence. Multi-copies insertion transformants were screened on G418 plates. After the induction by 1% methanol for 72 hours, the expression of Bm-TFF2 came up to the best quantity which was about 50 mg in 1L medium, and 80% saturation ammonium sulfate was suitable to collect the Bm-TFF2 protein, as identified by SDS-PAGE and Western blotting assay. The results showed that the plasmid of Bm-TFF2-pPIC9K was constructed successfully and expressed abundantly in eukaryotic expression system, which lies basis for researching further the biological activities and the relationship of structure and functions of Bm-TFF2.

In vitro and in vivo antitumor activity of melatonin receptor agonists

Melatonin has been shown to inhibit the proliferation of estrogen receptor α (ERα)-positive human breast cancer cells in vitro and suppress the growth of carcinogen-induced mammary tumors in rats. Melatonin's antiproliferative effect is mediated, at least in part, through the MT1 melatonin receptor and mechanisms involving modulation of the estrogen-signaling pathway. To develop melatonin analogs with greater therapeutic effects, we have examined the in vitro and in vivo antimitotic activity of two MT1/MT2 melatonin receptor agonists, S23219-1 and S23478-1. In our studies, both agonists are quite effective at suppressing the growth of MCF-7 human breast cancer cells. At a concentration of 10⁻⁶ m, S23219-1 and S23478-1 inhibited the growth of MCF-7 cells by 60% and 73%, respectively. However, S23478-1 is more effective than melatonin and S23219-1 at repressing the expression and transactivation of the ERα, and modulating the expression of pancreatic spasmolytic polypeptide (pS2), an estrogen-regulated gene. The melatonin agonist S23478-1 exhibited enhanced antitumor potency in the subsequent studies in our animal model. At a dosage of 25 mg/kg/day, S23478-1 is more efficacious than melatonin at inducing regression of the established N-nitroso-N-methyl-urea-induced rat mammary tumors. This dose of S23478-1 (25 mg/kg/day) generated a significant (P < 0.05) overall regression response of 52%. Furthermore, at this dosage, S23478-1 is more effective than melatonin at suppressing the estrogen-signaling pathway and promoting tumor cell apoptosis, significantly increasing the expression of the pro-apoptotic protein Bax, while decreasing the expression of ERα and the anti-apoptotic protein Bcl-2.

The transcription factor MIST1 is a novel human gastric chief cell marker whose expression is lost in metaplasia, dysplasia, and carcinoma

The lack of reliable molecular markers for normal differentiated epithelial cells limits understanding of human gastric carcinogenesis. Recognized precursor lesions for gastric adenocarcinoma are intestinal metaplasia and spasmolytic polypeptide expressing metaplasia (SPEM), defined here by ectopic CDX2 and TFF2 expression, respectively. In mice, expression of the bHLH transcription factor MIST1, normally restricted to mature chief cells, is down-regulated as chief cells undergo experimentally induced metaplasia. Here, we show MIST1 expression is also a specific marker of human chief cells. SPEM, with and without MIST1, is present in human lesions and, akin to murine data, likely represents transitional (TFF2(+)/MIST1(+) = "hybrid"-SPEM) and established (TFF2(+)/MIST1(-) = SPEM) stages. Co-visualization of MIST1 and CDX2 shows similar progressive loss of MIST1 with a transitional, CDX2(+)/MIST1(-) hybrid-intestinal metaplasia stage. Interinstitutional analysis and comparison of findings in tissue microarrays, resection specimens, and biopsies (n > 400 samples), comprising the entire spectrum of recognized stages of gastric carcinogenesis, confirm MIST1 expression is restricted to the chief cell compartment in normal oxyntic mucosa, rare in established metaplastic lesions, and lost in intraepithelial neoplasia/dysplasia and carcinoma of various types with the exception of rare chief cell carcinoma ( approximately 1%). Our findings implicate MIST1 as a reliable marker of mature, healthy chief cells, and we provide the first evidence that metaplasia in humans arises at least in part from the chief cell lineage.

Targeted deletion of Kcne2 causes gastritis cystica profunda and gastric neoplasia

Gastric cancer is the second leading cause of cancer death worldwide. Predisposing factors include achlorhydria, Helicobacter pylori infection, oxyntic atrophy and TFF2-expressing metaplasia. In parietal cells, apical potassium channels comprising the KCNQ1 α subunit and the KCNE2 β subunit provide a K⁺ efflux current to facilitate gastric acid secretion by the apical H⁺K⁺ATPase. Accordingly, genetic deletion of murine Kcnq1 or Kcne2 impairs gastric acid secretion. Other evidence has suggested a role for KCNE2 in human gastric cancer cell proliferation, independent of its role in gastric acidification. Here, we demonstrate that 1-year-old Kcne2^−/− mice in a pathogen-free environment all exhibit a severe gastric preneoplastic phenotype comprising gastritis cystica profunda, 6-fold increased stomach mass, increased Ki67 and nuclear Cyclin D1 expression, and TFF2- and cytokeratin 7-expressing metaplasia. Some Kcne2^−/−mice also exhibited pyloric polypoid adenomas extending into the duodenum, and neoplastic invasion of thin walled vessels in the sub-mucosa. Finally, analysis of human gastric cancer tissue indicated reduced parietal cell KCNE2 expression. Together with previous findings, the results suggest KCNE2 disruption as a possible risk factor for gastric neoplasia.

DNA methylation patterns of ulcer-healing genes associated with the normal gastric mucosa of gastric cancers

Recent evidence suggests that gastric mucosal injury induces adaptive changes in DNA methylation. In this study, the methylation status of the key tissue-specific genes in normal gastric mucosa of healthy individuals and cancer patients was evaluated. The methylation-variable sites of 14 genes, including ulcer-healing genes (TFF1, TFF2, CDH1, and PPARG), were chosen from the CpG-island margins or non-island CpGs near the transcription start sites. The healthy individuals as well as the normal gastric mucosa of 23 ulcer, 21 non-invasive cancer, and 53 cancer patients were examined by semiquantitative methylation-specific polymerase chain reaction (PCR) analysis. The ulcer-healing genes were concurrently methylated with other genes depending on the presence or absence of CpG-islands in the normal mucosa of healthy individuals. Both the TFF2 and PPARG genes were frequently undermethylated in ulcer patients. The over- or intermediate-methylated TFF2 and undermethylated PPARG genes was more common in stage-1 cancer patients (71%) than in healthy individuals (10%; odds ratio [OR], 21.9) and non-invasive cancer patients (21%; OR, 8.9). The TFF2-PPARG methylation pattern of cancer patients was stronger in the older-age group (> or =55 yr; OR, 43.6). These results suggest that the combined methylation pattern of ulcer-healing genes serves as a sensitive marker for predicting cancer-prone gastric mucosa.

Alterations in gastric mucosal lineages before or after acute oxyntic atrophy in gastrin receptor and H2 histamine receptor-deficient mice

Spasmolytic polypeptide (SP/TFF2)-expressing metaplasia (SPEM) is induced by oxyntic atrophy and is known as a precancerous or paracancerous lesion. We seek to determine whether the gastrin receptor or H(2) histamine receptor influence the development of SPEM. DMP-777 was administered to gastrin receptor and/or H(2) receptor-deficient mice and wild-type mice. Gastric mucosal lineage changes were analyzed. The mucosa from double knockout mice and H(2) receptor knockout mice contained elevated numbers of dual TFF2 and intrinsic factor immunoreactive cells even before DMP-777 treatment. All genotypes of mice showed SPEM after 7-day treatment. In all types of knockout mice, the number of TFF2 immunoreactive cells remained elevated after cessation of treatment. The H(2) receptor and gastrin receptor do not affect emergence of SPEM. However, it is suggested that the absence of H(2) receptor signaling causes a delay in the maturation of chief cells from mucous neck cells.

Intestinal trefoil factor maybe useful in prophylaxis of acute graft-versus-host disease

Graft-versus-host disease (GVHD) is a major complication of hematopoietic cell transplantation, GVHD pathophysiology can be divided into three phases, damage to the gastrointestinal (GI) tract in phase 1, principally by inflammatory cytokines, amplifies LPS release and leads to the "cytokine storm" characteristic of severe acute GVHD. It has been proved that disruption of phase 1 of the GVHD cascade is effective in prophylaxis of acute GVHD. Intestinal trefoil factor (ITF), a member of trefoil factor family (TFF) domain peptides, was proved to be very effective in prevention and healing of acute dextran sodium sulfate-induced colitis, and was also involved in protection against and recovery from intestinal mucositis induced by radiation and chemotherapy. So we hypothesise that ITF protects the intestinal tract mucosa from lesions and that it maybe useful in prophylaxis of acute GVHD. ITF can block GI tract damage in phase 1, preventing the amplification of the cascade. ITF may represent a novel strategy for the separation of GVHD and graft-versus-leukemia (GVL), and may serve as an effective adjunct to clinical regimens of GVHD prophylaxis.

Molecular mechanism on healing process of peptic ulcer

Ulcer healing process is an intricate and active process including reconstruction process of mucosa through formation of granulation tissue. Granulation tissue formation takes place by means of formation of ulcer base, formation of blood vessel (angiogenesis) and re-establishment of glandular architecture. The process of granulation tissue formation on the ulcer base takes place 48-72 hours after ulceration process occurs. These three phases involve various genes grouped according to their activated time, i.e. the initial response genes, intermediate response gene and late response genes. Initial response genes are activated in 30 minutes to 2 hours time, e.g EGF-R, c-fos, c-jun, egr-1, Sp-1, TFF-2/SP. Intermediate response genes are activated for 6 hours to 2 days, eg EGF, bFGF, PDGF and VEGF. Late response genes are activated for 14 days, e.g. HGF, ITF, c-met/HGF-R.

Decreased TFF2 expression in the gastric antrum in patients infected with CagA-positive Helicobacter pylori

BACKGROUND

The trefoils factor family is a relatively new family of peptides. Their abundant expression in the epithelial cells of the gastrointestinal tract in the normal physiological state and in various ulcerative conditions suggests an important role in mucosal defense and repair. Infection with Helicobacter pylori interferes with normal mucosal activity.

OBJECTIVES

To investigate whether H. pylori infection alters the expression of trefoils TFF1 and TFF2 in the gastric mucosa of patients with H. pylori-associated chronic active gastritis, positive or negative for the CagA strain.

METHODS

During investigation for dyspepsia, gastric biopsies and blood samples were obtained from patients who underwent upper gastrointestinal endoscopy. Rapid urease testing, histology for determination of H. pylori-associated CAG and Western analysis for TFF1 and TFF2 expression with antisera were performed. CagA state was determined using a commercial kit.

RESULTS

TFF2 expression was significantly reduced in both groups of patients with H. pylori-associated CAG compared to healthy patients without H. pylori infection, particularly in CagA-positive patients. TFF1 expression showed a tendency of reduction (not significant) in this group only.

CONCLUSIONS

These results suggest that H. pylori-associated CAG has a deleterious effect on the expression of TFF2 in the gastric antrum. This reduced expression may contribute to the damage induced to the gastric mucosa by H. pylori.