Experimental ulceration leads to sequential expression of spasmolytic polypeptide, intestinal trefoil factor, epidermal growth factor and transforming growth factor alpha mRNAs in rat stomach

A Rapid Self-Assembling Peptide Hydrogel for Delivery of TFF3 to Promote Gastric Mucosal Injury Repair

Self-assembled peptide-based nanobiomaterials exhibit promising prospects for drug delivery applications owing to their commendable biocompatibility and biodegradability, facile tissue uptake and utilization, and minimal or negligible unexpected toxicity. TFF3 is an active peptide autonomously secreted by gastric mucosal cells, possessing multiple biological functions. It acts on the surface of the gastric mucosa, facilitating the repair process of gastric mucosal damage. However, when used as a drug, TFF3 faces significant challenges, including short retention time in the gastric mucosal cavity and deactivation due to degradation by stomach acid. In response to this challenge, we developed a self-assembled short peptide hydrogel, Rqdl10, designed as a delivery vehicle for TFF3. Our investigation encompasses an assessment of its properties, biocompatibility, controlled release of TFF3, and the mechanism underlying the promotion of gastric mucosal injury repair. Congo red/aniline blue staining revealed that Rqdl10 promptly self-assembled in PBS, forming hydrogels. Circular dichroism spectra indicated the presence of a stable β-sheet secondary structure in the Rqdl10 hydrogel. Cryo-scanning electron microscopy and atomic force microscopy observations demonstrated that the Rqdl10 formed vesicle-like structures in the PBS, which were interconnected to construct a three-dimensional nanostructure. Moreover, the Rqdl10 hydrogel exhibited outstanding biocompatibility and could sustainably and slowly release TFF3. The utilization of the Rqdl10 hydrogel as a carrier for TFF3 substantially augmented its proliferative and migratory capabilities, while concurrently bolstering its anti-inflammatory and anti-apoptotic attributes following gastric mucosal injury. Our findings underscore the immense potential of the self-assembled peptide hydrogel Rqdl10 for biomedical applications, promising significant contributions to healthcare science.

Quantitative proteomic screening uncovers candidate diagnostic and monitoring serum biomarkers of ankylosing spondylitis

BACKGROUND

We sought to discover serum biomarkers of ankylosing spondylitis (AS) for diagnosis and monitoring disease activity.

METHODS

We studied biologic-treatment-naïve AS and healthy control (HC) patients' sera. Eighty samples matched by age, gender, and race (1:1:1 ratio) for AS patients with active disease, inactive disease, and HC were analyzed with SOMAscan™, an aptamer-based discovery platform. T-tests tests were performed for high/low-disease activity AS patients versus HCs (diagnosis) and high versus low disease activity (Monitoring) in a 2:1 and 1:1 ratio, respectively, to identify differentially expressed proteins (DEPs). We used the Cytoscape Molecular Complex Detection (MCODE) plugin to find clusters in protein-protein interaction networks and Ingenuity Pathway Analysis (IPA) for upstream regulators. Lasso regression analysis was performed for diagnosis.

RESULTS

Of the 1317 proteins detected in our diagnosis and monitoring analyses, 367 and 167 (317 and 59, FDR-corrected q < .05) DEPs, respectively, were detected. MCODE identified complement, IL-10 signaling, and immune/interleukin signaling as the top 3 diagnosis PPI clusters. Complement, extracellular matrix organization/proteoglycans, and MAPK/RAS signaling were the top 3 monitoring PPI clusters. IPA showed interleukin 23/17 (interleukin 22, interleukin 23A), TNF (TNF receptor-associated factor 3), cGAS-STING (cyclic GMP-AMP synthase, Stimulator of Interferon Gene 1), and Jak/Stat (Signal transducer and activator of transcription 1), signaling in predicted upstream regulators. Lasso regression identified a Diagnostic 13-protein model predictive of AS. This model had a sensitivity of 0.75, specificity of 0.90, a kappa of 0.59, and overall accuracy of 0.80 (95% CI: 0.61-0.92). The AS vs HC ROC curve was 0.79 (95% CI: 0.61-0.96).

CONCLUSION

We identified multiple candidate AS diagnostic and disease activity monitoring serum biomarkers using a comprehensive proteomic screen. Enrichment analysis identified key pathways in AS diagnosis and monitoring. Lasso regression identified a multi-protein panel with modest predictive ability.

Investigation of the Relationship Between Trefoil Factor Family Peptides and Sinonasal Inflammation

The trefoil factor family (TFF) is a relatively new family of peptides. In some studies, an association between trefoil factors and inflammatory diseases of the nasal and paranasal sinuses has been suggested. However, it is still not clear whether there is a relationship between trefoil peptides and inflammation of the respiratory tract. The aims of this study are to determine the presence of TFF1, TFF2, and TFF3 in the nasal mucosa and investigate their relationships with inflammation by using rat models of various sinonasal inflammations. Nasal tampon, lipopolysaccharide, and ovalbumin were used to generate rat models of sinonasal inflammation, i.e., rhinosinusitis and allergic rhinitis. The study was conducted on seventy rats in seven groups, each with ten rats: four groups with rhinosinusitis, two groups with allergic rhinitis, and a control group. Histological evaluation of sinonasal mucosa from all rats was performed, and Trefoil factors were investigated using immunohistochemical methods. All three TFF peptides were detected in rat nasal mucosa by histological evaluation. No significant differences in the trefoil factor scores were observed among the study groups. A significant correlation between the TFF1 and TFF3 scores and loss of cilia was identified (p < 0.05). In conclusion, no direct relationship between sinonasal inflammation and TFF scores was observed. However, a possible association between the TFF and epithelial damage or regeneration in sinonasal inflammation can be suggested based on the correlation observed between the TFF1 and TFF3 scores and scores of cilia loss.

Pathological and therapeutic roles of bioactive peptide trefoil factor 3 in diverse diseases: recent progress and perspective

Trefoil factor 3 (TFF3) is the last small-molecule peptide found in the trefoil factor family, which is mainly secreted by intestinal goblet cells and exerts mucosal repair effect in the gastrointestinal tract. Emerging evidence indicated that the TFF3 expression profile and biological effects changed significantly in pathological states such as cancer, colitis, gastric ulcer, diabetes mellitus, non-alcoholic fatty liver disease, and nervous system disease. More importantly, mucosal protection would no longer be the only effect of TFF3, it gradually exhibits carcinogenic activity and potential regulatory effect of nervous and endocrine systems, but the inner mechanisms remain unclear. Understanding the molecular function of TFF3 in specific diseases might provide a new insight for the clinical development of novel therapeutic strategies. This review provides an up-to-date overview of the pathological effects of TFF3 in different disease and discusses the binding proteins, signaling pathways, and clinical application.

Chemical Synthesis of TFF3 Reveals Novel Mechanistic Insights and a Gut-Stable Metabolite

TFF3 regulates essential gastro- and neuroprotective functions, but its molecular mode of action remains poorly understood. Synthetic intractability and lack of reliable bioassays and validated receptors are bottlenecks for mechanistic and structure–activity relationship studies. Here, we report the chemical synthesis of TFF3 and its homodimer via native chemical ligation followed by oxidative folding. Correct folding was confirmed by NMR and circular dichroism, and TFF3 and its homodimer were not cytotoxic or hemolytic. TFF3, its homodimer, and the trefoil domain (TFF3_10-50) were susceptible to gastrointestinal degradation, revealing a gut-stable metabolite (TFF3_7-54; t_1/2 > 24 h) that retained its trefoil structure and antiapoptotic bioactivity. We tried to validate the putative TFF3 receptors CXCR4 and LINGO2, but neither TFF3 nor its homodimer displayed any activity up to 10 μM. The discovery of a gut-stable bioactive metabolite and reliable synthetic accessibility to TFF3 and its analogues are cornerstones for future molecular probe development and structure–activity relationship studies.

Bioadhesive hydrogels demonstrating pH-independent and ultrafast gelation promote gastric ulcer healing in pigs

Hydrogels are soft materials used in an array of biomedical applications. However, the in situ formation of hydrogels at target sites, particularly in dynamic in vivo environments, usually requires a prolonged gelation time and results in poor adhesion. These limitations cause considerable loss of both hydrogel mass and encapsulated therapeutic cargoes, thereby compromising treatment outcomes. Here, we report the development of a hydrogel based on thiourea-catechol reaction to enhance the bioadhesion. Compared with classical bioadhesive hydrogels, our hydrogels show enhanced mechanical properties, exceedingly short curing time, and pH-independent gelation with a much lower oxidant concentration. We further report the robust adhesion of our hydrogels to acidic gastric tissues and easy delivery to the porcine stomach via endoscopy. The delivered hydrogels adhered to ulcer sites in vivo for at least 48 hours. Hydrogel treatment of gastric ulcers in rodent and porcine models accelerated ulcer healing by suppressing inflammation and promoting re-epithelization and angiogenesis. The improved retention of proregenerative growth factors and reduced exposure to external catabolic factors after hydrogel application may contribute to the observed therapeutic outcomes. Our findings reveal a promising biomaterial-based approach for treating gastrointestinal diseases.

Immunohistochemical Studies of Age-Related Changes in Cell Proliferation and Angiogenesis during the Healing of Acetic Acid-Induced Gastric Ulcers in Rats

Cell proliferation and angiogenesis are of utmost importance for healing to take place. The KI67 and EGFR proteins are markers of cell proliferation, while CD31 and factor VIII are markers of angiogenesis. To elucidate the mechanism responsible for delayed healing of the gastric injury in old age, we analyzed the expression of these markers in rats of different months during the healing of an acetic acid-induced gastric ulcer. Male Wistar rats (aged 3, 6, 12, and 18 months) divided into four groups, according to their ages, formed the experimental animals. Stomach tissue samples were collected on days 3, 7, 14, and 21 after induction for assessment of ulcer healing. The area of gastric mucosa healed was inversely proportional to age. The expression of markers of proliferation (KI67 and EGFR) and angiogenesis (factor VIII and CD31) decreased significantly (p < 0.05) in older rats when compared with younger ones (3 months > six months > 12 months > 18 months) on days 7, 14, and 21 after induction of gastric ulcer. This study revealed that the slower gastric ulcer healing rate in older rats might be due to reduced epithelial cell proliferation and angiogenic activities.

Structure, Function, and Therapeutic Potential of the Trefoil Factor Family in the Gastrointestinal Tract

Trefoil factor family peptides (TFF1, TFF2, and TFF3) are key players in protecting, maintaining, and repairing the gastrointestinal tract. Accordingly, they have the therapeutic potential to treat and prevent a variety of gastrointestinal disorders associated with mucosal damage. TFF peptides share a conserved motif, including three disulfide bonds that stabilize a well-defined three-loop-structure reminiscent of a trefoil. Although multiple functions have been described for TFF peptides, their mechanisms at the molecular level remain poorly understood. This review presents the status quo of TFF research relating to gastrointestinal disorders. Putative TFF receptors and protein partners are described and critically evaluated. The therapeutic potential of these peptides in gastrointestinal disorders where altered mucosal biology plays a crucial role in the underlying etiology is discussed. Finally, areas of investigation that require further research are addressed. Thus, this review provides a comprehensive update on TFF literature as well as guidance toward future research to better understand this peptide family and its therapeutic potential for the treatment of gastrointestinal disorders.

Changes in novel gastrointestinal and renal injury markers in the blood plasma of sheep following increasing intravenous doses of tolfenamic acid

The administration of high doses of non-steroidal anti-inflammatory drugs (NSAID), such as tolfenamic acid (TA), has undesirable effects on different organs. Some novel biomarkers have been reported that can determine the gastrointestinal and renal injury caused by a high dose of NSAIDs or other toxic substances. This study was aimed at determining the changes in gastrointestinal (TFF2 and HYP), renal (NGAL and KIM-1) and cardiac (cTn-I, CK-MB) injury markers after the use of increasing intravenous doses of TA in sheep. TA was administered intravenously to groups of six sheep each, at the dose levels of 0 (Group 0, i.e., G0), 2 (G2), 4 (G4), 8 (G8) and 16 (G16) mg/kg. The concentrations of the studied biomarkers were measured at 3, 9, 18 and 36 h after administration of TA. The TFF2 and NGAL concentrations in G16 were found to be significantly higher (P < 0.05) than in the other groups except for G8 at different sampling times. HYP concentration in G16 was observed to be significantly (P < 0.05) lower than that in all other groups at 36 h. KIM-1 level in G16 was significantly (P < 0.05) higher than in all other groups at different sampling times. An increase in the renal markers, KIM-1 and NGAL, in G8 was observed before any change in plasma creatinine and urea. The cardiac marker cTn-I in G16 was significantly (P < 0.05) higher than in other groups at different sampling times. The results showed that the novel biomarkers (HYP, TFF2, NGAL, and KIM-1) can be used to determine gastric and renal injury in sheep.

Trefoil Factor Peptides and Gastrointestinal Function

Trefoil factor (TFF) peptides, with a 40-amino acid motif and including six conserved cysteine residues that form intramolecular disulfide bonds, are a family of mucin-associated secretory molecules mediating many physiological roles that maintain and restore gastrointestinal (GI) mucosal homeostasis. TFF peptides play important roles in response to GI mucosal injury and inflammation. In response to acute GI mucosal injury, TFF peptides accelerate cell migration to seal the damaged area from luminal contents, whereas chronic inflammation leads to increased TFF expression to prevent further progression of disease. Although much evidence supports the physiological significance of TFF peptides in mucosal defenses, the molecular and cellular mechanisms of TFF peptides in the GI epithelium remain largely unknown. In this review, we summarize the functional roles of TFF1, 2, and 3 and illustrate their action mechanisms, focusing on defense mechanisms in the GI tract.

Loss of Trefoil Factor 2 From Pancreatic Duct Glands Promotes Formation of Intraductal Papillary Mucinous Neoplasms in Mice

BACKGROUND & AIMS

Little is known about the origin of pancreatic intraductal papillary mucinous neoplasms (IPMN). Pancreatic duct glands (PDGs) are gland-like outpouches budding off the main pancreatic ducts that function as a progenitor niche for the ductal epithelium; they express gastric mucins and have characteristics of side-branch IPMNs. We investigated whether PDGs are a precursor compartment for IPMNs and the role of Trefoil factor family 2 (TFF2)-a protein expressed by PDGs and the gastric mucosa that are involved in epithelial repair and tumor suppression.

METHODS

We obtained pancreatectomy specimens from 20 patients with chronic pancreatitis, 13 with low-grade side-branch IPMNs, and 15 patients with PDAC; histologically normal pancreata were used as controls (n = 18). Samples were analyzed by immunohistochemistry to detect TFF1 and TFF2 and cell proliferation. We performed mitochondrial DNA mutational mapping studies to determine the cell lineage and fate of PDG cells. Pdx1-Cre;LSL-KRAS^G12D (KC) mice were bred with TFF2-knockout mice to generate KC/Tff2^-/- and KC/Tff2^+/- mice. Pancreata were collected and histologically analyzed for formation of IPMN, pancreatic intraepithelial neoplasias, and PDAC, in addition to proliferation and protein expression. Human pancreatic ductal epithelial cells and PDAC cell lines were transfected with vectors to overexpress or knock down TFF2 or SMAD4.

RESULTS

Histologic analysis of human samples revealed gastric-type IPMN to comprise 2 molecularly distinct layers: a basal crypt segment that expressed TFF2 and overlying papillary projections. Proliferation occurred predominantly in the PDG-containing basal segments. Mitochondrial mutation mapping revealed a 97% match between the profiles of proliferating PDG cells and their overlying nonproliferative IPMN cells. In contrast to KC mice, 2-month-old KC/Tff2^+/- and KC/Tff2^-/- mice developed prominent papillary structures in the duct epithelium with cystic metaplasia of the PDG, which resembled human IPMN; these expressed gastric mucins (MUC5AC and MUC6), but not the intestinal mucin MUC2. KC/TFF2-knockout mice developed a greater number and higher grade of pancreatic intraepithelial neoplasias than KC mice, and 1 mouse developed an invasive adenocarcinoma. Expression of TFF2 reduced proliferation of PDAC cells 3-fold; this effect required up-regulation and activation of SMAD4. We found expression of TFF2 to be down-regulated in human PDAC by hypermethylation of its promoter.

CONCLUSIONS

In histologic analyses of human IPMNs, we found PDGs to form the basal segment and possibly serve as a progenitor compartment. TFF2 has tumor-suppressor activity in the mouse pancreas and prevents formation of mucinous neoplasms.

Reproductive factors, hormone use and gastric cancer risk: The Singapore Chinese Health Study

Gastric cancer incidence varies greatly worldwide, but is consistently twice as high in men than in women. The hormone-related factors hypothesized to be associated with lower risk of gastric cancer in women have not been fully explored in populations with a high background risk of gastric cancer. The Singapore Chinese Health Study (SCHS) is a prospective cohort study in which 34,022 of the participants enrolled between 1993 and 1998 were women between 45 and 74 years of age. Information on reproductive histories, hormone replacement therapy (HRT) and oral contraceptive (OC) use was collected through in-person interviews at baseline. As of December 31, 2013, 269 incident gastric cancer cases were identified. Multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated to evaluate gastric cancer risk associations. Older age at natural menopause (≥55 versus <45 years: HR = 0.50, 95% CI: 0.25-0.99), type of menopause (other versus natural: HR = 0.48, 95% CI: 0.27-0.87) and greater years of menstrual cycling (fourth versus first quartile: HR = 0.67, 95% CI: 0.46-0.96) were associated with a decreased risk of gastric cancer. Ever use of OCs and HRT was also associated with reduced risk of gastric cancer; the multivariable-adjusted HRs (95% CIs) were 0.40 (0.17-0.90) for use of HRT >3 years and 0.67 (0.47-0.94) for ever use of OCs, compared with never use. Reproductive factors associated with a longer window of fertility and the use of exogenous hormones were shown to reduce gastric cancer development in a cohort of Chinese women with a high background risk of gastric cancer.

Trefoil factor family peptides – friends or foes?

Trefoil factor family (TFF) peptides are a group of molecules bearing a characteristic three-loop trefoil domain. They are mainly secreted in mucous epithelia together with mucins but are also synthesized in the nervous system. For many years, TFF peptides were only known for their wound healing and protective function, e.g. in epithelial protection and restitution. However, experimental evidence has emerged supporting a pivotal role of TFF peptides in oncogenic transformation, tumorigenesis and metastasis. Deregulated expression of TFF peptides at the gene and protein level is obviously implicated in numerous cancers, and opposing functions as oncogenes and tumor suppressors have been described. With regard to the regulation of TFF expression, epigenetic mechanisms as well as the involvement of various miRNAs are new, promising aspects in the field of cancer research. This review will summarize current knowledge about the expression and regulation of TFF peptides and the involvement of TFF peptides in tumor biology and cancerogenesis.

Heterogeneous Nuclear Ribonucleoprotein A1 Improves the Intestinal Injury by Regulating Apoptosis Through Trefoil Factor 2 in Mice with Anti-CD3-induced Enteritis

BACKGROUND

The role of hnRNP A1 in the onset of intestinal inflammation remains unclear. This study investigated the function of hnRNP A1 in mice enteritis models.

METHODS

C57Bl6/J mice were intraperitoneally injected with anti-CD3 antibodies to develop enteritis. In the DSS-induced colitis group, the mice were allowed free access to 3% DSS solution in their drinking water for 5 days. 3H-mannitol flux and complementary DNA array tests were used to assess the intestinal barrier function and messenger RNA (mRNA) expression, respectively. Real-time PCR was performed after immunoprecipitation with anti-hnRNP antibodies to determine the specific mRNA binding of hnRNP A1.

RESULTS

The hnRNP A1 expression was increased in the intestine of the mouse at 24 hours after treatment with anti-CD3 antibodies and 5 days after starting DSS administration. Small interfering RNA (siRNA) against hnRNP A1 exacerbated the intestinal injuries in both models. According to the microarray analysis, trefoil factor 2 (TFF2) was identified as a candidate molecule targeted by hnRNP A1 in the anti-CD3 antibody-induced enteritis group. Moreover, the binding between hnRNP A1 and TFF2 mRNA significantly increased in the enteritis mice, and the administration of siRNA against either hnRNP A1 or TFF2 exacerbated the degree of intestinal injury. In the DSS-induced colitis group, treatment with the siRNA of hnRNP A1 worsened the intestinal injury, while the expression of TFF3 did not change.

CONCLUSIONS

hnRNP A1 improves intestinal injury in anti-CD3 antibody-induced enteritis mice through the upregulation of TFF2, which regulates apoptosis and enhances epithelial restoration, whereas this molecule ameliorates DSS-induced colitis through a different pathway.

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 1 as a marker of mucosal damage of the gastrointestinal tract in children with sepsis

Intestinal ischemia and reperfusion is a common pathway for many diseases in children. The objective of our study was an analysis of Trefoil factor 1 levels dynamics in patients with SIRS or septic condition during a 5-day period. Analysis of TFF1 levels dynamics revealed that TFF1 levels kept steady state during the 5-day period. TFF1 levels were similar in patients with SIRS, sepsis and severe sepsis. Significantly higher levels of TFF1 were in patients with septic shock and MODS.

Trefoil factor family peptides in normal and diseased human pancreas

OBJECTIVES

Trefoil factor family (TFF) peptides promote wound healing in the gut. Recent evidence has suggested that TFF3 may be a pancreatic mitogen, an unusual role for TFF peptides. We sought to clarify human pancreatic TFF and mucin expression and performed in vitro experiments to see how pancreatic cell lines respond to TFF3 in particular.

METHODS

Samples of normal and diseased pancreas (chronic pancreatitis, pancreatic intraepithelial neoplasia, neuroendocrine tumors, and pancreatic ductal adenocarcinoma [PDAC]) were studied by immunohistochemistry and in situ hybridization. Pancreatic cell lines were challenged with TFF2 and TFF3 in wound and migration assays.

RESULTS

In normal islets, colocalization of insulin or glucagon with TFF3 was common. All TFF messenger RNAs were seen in ductal epithelium. Adenocarcinomas expressed all TFF messenger RNAs. Normal ducts were mucin free; MUC5AC was strongest in pancreatic intraepithelial neoplasia and chronic pancreatitis but was reduced in PDAC. TFF2 induced Panc-1 migration and accelerated wound closure in Capan-2 and COLO-357. Double immunohistochemistry for insulin or TFF3 and Ki67 colabeled only very rare islet cells. TFF3-positive PDAC ducts showed some Ki67 colocalization.

CONCLUSIONS

No correlation between TFF3 or insulin and Ki67 was seen without ductal hyperplasia. TFF2 may assist pancreatic tumor cell movement, but TFF3 may not be a pancreatic mitogen.

Bacterial expression and purification of biologically active human TFF2

Human trefoil factor 2 (hTFF2) is considered as one of the most important initiators of mucosal healing in the gastrointestinal tract by promoting cell migration and suppressing apoptosis. However, it is hard to obtain hTFF2 from human tissue and many recombinant hTFF2 produced in vitro exist as fusion proteins. The purpose of the present study was to produce native hTFF2 while maintaining its biological activities. The open reading frame of hTFF2 was inserted into a pET-32a(+) expression vector, and hTFF2-TRX fusion protein was successfully expressed in Escherichia coli and purified by Nickel-nitrilotriacetic acid affinity chromatography and reverse-phase HPLC steps. The recombinant fusion protein (purity>95%) was cleaved by Factor Xa at 23 Degrees Celsius to release hTFF2. After removal of Factor Xa and undigested fusion proteins, hTFF2 was purified and identified by SDS-PAGE and Western blotting. The yield of recombinant hTFF2 was about 5 mg/L. The recombinant hTFF2 could promote IEC-6 cells migration and in vitro wound healing via the activation of ERK1/2. Recombinant hTFF2 could also inhibit apoptosis of HCT-116 cells induced by 50 μmol/L ceramide. In summary, our results showed that the recombinant hTFF2 was expressed in E. coli and successfully purified after cleavage with the fusion partner with high yield while maintaining its biological activities. Recombinant hTFF2 might be useful for investigating the molecular mechanism of hTFF2 and development of hTFF2-related drugs.

Altered miRNA expression patterns in Tff2 knock-out mice correlate with cellular pathways of neoplastic development and caloric metabolism

The trefoil peptide family, consisting in mammals of three members namely TFF1, 2 and 3, plays a cytoprotective role in epithelial cells of various tissues, mainly in the digestive tract. Tff1, Tff2 or Tff3 knock-out mouse models developed various kinds of gastrointestinal impairment. microRNAs are known to be novel gene regulators. We aimed to investigate the physiological role of such miRNAs in Tff2 knock-out mice. Whole miRNome profiling and in silico analysis were performed for Tff2-KO and WT mice. Our latest data explored the role of miRNAs in the regulatory cascades and molecular processes of Tff2^−/− mice. As much as 6% of the Tff2-KO mice miRNome was significantly dys-regulated. Further in silico analysis suggests that the respective dys-regulated part of the miRNome is involved in human pathological processes, including pancreatic, colorectal and basal cell cancer. Additionally, the dys-regulated miRNome targets pathways involved in carbohydrate metabolism and adipocytokine signaling. The latter links deficient caloric maintenance in Tff2 and previous observation in Tff3-KO mice with miRNAs. In summary, our proof-of-concept study indicates that miRNAs may play an important role in the regulatory processes of the trefoil peptide family, especially in the regulation of cancer-related cascades.

Growth hormone upregulates intestinal trefoil factor expression in the ileum of rats after γ-radiation

Growth hormone (GH) and intestinal trefoil factor (ITF) have been involved in intestinal protection and repair. This study investigates the effects of GH administration on ITF expression and histological changes associated with tissue injury in an intestinal rat model of radiation. Adult male rats were divided into four groups: control, GH, radiation and radiation + GH (GHyRAD). Ileum samples were obtained at 2 or 72 h after radiation and processed to determine ITF levels (mRNA and protein) by quantitative polymerase chain reaction, Western blot and immunohistochemistry. In addition, goblet ITF-positive cells were identified by immunohistochemistry at 72 h. Our results showed an upregulation of mRNA and protein production of ITF in ileum samples after GH and radiation + GH compared with control and irradiated samples. Irradiation alone affected ITF protein expression. However, irradiation after GH pretreatment produced the highest ITF mRNA and protein levels at both the tested time points. ITF-producing goblet cells were identified in intestinal villi (apical location). GH treatment increased the number of ITF-producing goblet cells, and radiation after GH treatment displayed further increase in the number of ITF-positive goblet cells. GH upregulates ITF in normal intestinal tissue. This upregulation is higher when radiation is given after GH treatment. Nevertheless, the mechanism by which GH regulates ITF expression remains unclear and is still under investigation. These results could open up new avenues in the therapeutic reparative and protective effects of GH during radiotherapy and chemotherapy.

Decrease of Trefoil factor 2 in cats with feline idiopathic cystitis

OBJECTIVE

To obtain new insights into aetiological backgrounds, and to search for diagnostic biomarkers by assessing the difference in urinary proteins between cats with spontaneous feline idiopathic cystitis (FIC) and healthy controls.

MATERIALS AND METHODS

Urine supernatants of 18 cats with FIC and 18 healthy control cats, and bladder biopsies of two FIC diseased cats and four healthy controls were included in the study. The Bradford method was used to determine protein quantity in urine supernatants. Urine was separated by two-dimensional (2-D) gel electrophoresis. Selected protein spots were excised from two-dimensional gels and analysed with tandem mass spectrometry. Validation of Trefoil factor 2 expression was realized with Western blot and immunohistochemistry. Western blot signal intensities were quantified with image quant software.

RESULTS

Eleven differentially expressed protein spots were identified between the 2-D gels of cats with FIC and control cats. Ten spots (only visible in the FIC gel) were identified as albumin and one spot (only visible in the control gel) was identified as Trefoil factor 2.Using quantification of Western blot signal intensities and immunohistochemistry a decrease in Trefoil factor 2 (TFF2) in cats with FIC could be revealed for the first time.

CONCLUSION

Deficiency in TFF2 possibly leads to impaired repairing abilities and immune response of the urothelium. The result could be a greater susceptibility to injury, inflammation and relapse. Therefore TFF2 deficiency might be an important event in FIC pathogenesis. Detection of a decrease in urinary TFF2 could serve as diagnostic biomarker, facilitating diagnosis. As FIC can serve as an animal model for human painful bladder syndrome/interstitial cystitis, the findings of this study might also be valuable for interstitial cystitis research and should be further investigated.

Overexpression of hTFF2 in the pET system and its in vitro pharmacological characterization

The trefoil factor family 2 (TFF2), a member of the trefoil factor family, plays a critical role in the defense and repair of gastrointestinal mucosa. However, its widespread application is hampered by difficulties in large-scale production of the recombinant protein suitable for clinical use. The aim of the present study was to produce hTFF2 by Escherichia coli expression system and explore its in vitro pharmacological characterization. hTFF2 gene encoding mature peptide was obtained by RT-PCR, and then inserted into the expression vector pET32a to construct the recombinant pET32a-hTFF2. After confirmation by gene sequencing, pET32a-hTFF2 was transformed into E. coli Origami B(DE3), and TrxA-hTFF2 fusion protein was expressed by conventional IPTG induction in a shake flask and analyzed with SDS-PAGE and Western-blot. Subsequently, TrxA-hTFF2 was isolated by Ni-NTA affinity chromatography, and ultrafiltration. Finally, we tested the effect of hTFF2 on cell migration in an in vitro restitution model and cell proliferation by MTT assay. The data revealed that the recombinant vector pET32a-hTFF2 was constructed successfully. TrxA-hTFF2 fusion protein was expressed to 246.5mg/L and its purity was above 95% after purification. SDS-PAGE and Western blot analyses showed that the fusion protein presented as a single band with a molecular weight of 32kDa. In vitro model of wounding demonstrated that hTFF2 enhanced migration activity by three folds. MTT assay exhibited a statistically significant dose-dependent growth-enhanced effect. Collectively, the results suggest that the recombinant hTFF2 was expressed in E. coli with high production, purity and biological activity.

Induction of trefoil factor (TFF)1, TFF2 and TFF3 by hypoxia is mediated by hypoxia inducible factor-1: implications for gastric mucosal healing

BACKGROUND AND PURPOSE

Mucosal microcirculation is compromised during gastric damage induced by non-steroidal anti-inflammatory drugs, such as aspirin. Consequently, oxygen supply to epithelial cells is decreased. The trefoil factor (TFF) peptides are involved in mechanisms of defence and repair in the gastrointestinal tract but their regulation at sites of gastric injury is unknown.

EXPERIMENTAL APPROACH

Hypoxia and expression of TFF genes and peptides were measured in the damaged stomach of aspirin-treated rats. In a human gastric cell line (AGS cells), the effects of hypoxia and of hypoxia inducible factor (HIF)-1 (through transient transfection of HIF-1alpha siRNA or over-expression of HIF-1alpha) on TFF gene expression were evaluated.

KEY RESULTS

Hypoxyprobe immunostaining, up-regulation of TFF2 (1.9-fold) and TFF3 (1.8-fold) and a non-significant increase of TFF1 (1.5-fold) mRNA were observed in the damaged stomach of aspirin-treated rats, compared with control animals. Hypoxia (3% O(2), 16 h) induced mRNA for TFF1 (5.8-fold), TTF2 (9.1-fold) and TFF3 (9.3-fold) in AGS cells, an effect mediated by HIF-1, as transient transfection of HIF-1alpha siRNA reduced the effects of hypoxia. Over-expression of HIF-1alpha by transfection in non-hypoxic epithelial cells produced a similar pattern of TFF induction to that observed with hypoxia and transactivated a TFF1 reporter construct.

CONCLUSIONS AND IMPLICATIONS

Hypoxia inducible factor-1 mediated the induction of TFF gene expression by hypoxia in gastric epithelial cells. Low oxygen levels and up-regulation of TFF gene expression in the damaged stomach of aspirin-treated rats suggest that hypoxia induced expression of TFF genes at sites of gastric injury.

Secreted trefoil factor 2 activates the CXCR4 receptor in epithelial and lymphocytic cancer cell lines

The secreted trefoil factor family 2 (TFF2) protein contributes to the protection of the gastrointestinal mucosa from injury by strengthening and stabilizing mucin gels, stimulating epithelial restitution, and restraining the associated inflammation. Although trefoil factors have been shown to activate signaling pathways, no cell surface receptor has been directly linked to trefoil peptide signaling. Here we demonstrate the ability of TFF2 peptide to activate signaling via the CXCR4 chemokine receptor in cancer cell lines. We found that both mouse and human TFF2 proteins (at approximately 0.5 microm) activate Ca2+ signaling in lymphoblastic Jurkat cells that could be abrogated by receptor desensitization (with SDF-1alpha) or pretreatment with the specific antagonist AMD3100 or an anti-CXCR4 antibody. TFF2 pretreatment of Jurkat cells decreased Ca2+ rise and chemotactic response to SDF-1alpha. In addition, the CXCR4-negative gastric epithelial cell line AGS became highly responsive to TFF2 treatment upon expression of the CXCR4 receptor. TFF2-induced activation of mitogen-activated protein kinases in gastric and pancreatic cancer cells, KATO III and AsPC-1, respectively, was also dependent on the presence of the CXCR4 receptor. Finally we demonstrate a distinct proliferative effect of TFF2 protein on an AGS gastric cancer cell line that expresses CXCR4. Overall these data identify CXCR4 as a bona fide signaling receptor for TFF2 and suggest a mechanism through which TFF2 may modulate immune and tumorigenic responses in vivo.

Lansoprazole promotes gastric mucosal cell proliferation and migration by activating p44/p42 mitogen-activated protein kinase

Cell proliferation and migration are important repair mechanisms in cell defect type mucosal injuries, such as peptic ulcers. To evaluate the level of cell restitution in vitro, we established a normalized assay system for analyzing the area of a tissue defect created in the center of a cultured cell layer. Although proton pump inhibitors are known to be potently effective in the treatment of peptic ulcers by inducing acid suppression, they are also effective in low-acid conditions, such as in gastric ulcers associated with severe atrophic gastritis of the corpus. The present study was designed to examine the pH-independent effect of lansoprazole (LPZ) on cell restitution in vitro. The mouse gastric mucosal cell line, GSM06, was cultured to confluence. A 4-fluoric ethylene-tipped aluminum stick was then used to produce a cell-free area in the center of the culture well. After measuring the area of the cell defect using a digital analyzer equipped with an inverted microscope, LPZ was added to each well; the area of the residual cell defect was then measured 6 and 24 hours after LPZ administration. To investigate the involvement of the p44/p42 mitogen-activated protein kinase (MAPK) and p38 MAPK in this process, PD98059 (a MEK inhibitor) or FR167653 (a p38 MAPK inhibitor) was added to the cell cultures. In a separate experiment, GSM06 cells were cultured to the subconfluent level, each test agent was added, and the cell number in each well was measured using an MTT assay 16 hours after the administration of the agents. Six hours after the addition of LPZ, a slight but significant increase in the cell restitution rate was observed in the LPZ-treated groups compared with that in the control group. After 24 hours, a further significant increase in the cell restitution rate was observed in the LPZ groups compared with that in the control group. While the addition of PD98059 significantly attenuated the cell restitution rate in the LPZ groups, the addition of FR167653 had no such effect. The total cell number in the subconfluent cell cultures was significantly increased in the LPZ-treated groups compared with that in the control group. In conclusion, LPZ promotes the healing of injured gastric mucosal cells following injury by enhancing cell proliferation and migration. Furthermore, the mechanism by which cell proliferation and migration is promoted by LPZ may involve the activation of p44/p42 MAPK.

Murine trefoil factor 3 does not directly modulate LPS-mediated dendritic cell function

Peptides of the trefoil factor family (TFF) are expressed along the gastro-intestinal tract. They protect mucous epithelia from damage and contribute to mucosal repair, which is essential for preventing inflammation. Moreover, it has been suggested that TFF2 and TFF3, in particular, play a role in regulating immune responses. Depending on their activation status, dendritic cells (DC) can initiate either tolerance or immunity. This study, by comparing LPS-induced maturation of mTFF3-treated DC and non-treated DC, investigated whether murine TFF3 directly regulated DC function. mTFF3-treated DC and non-treated DC did not differ phenotypically or functionally. Both populations expressed, both before and after LPS-stimulation, similar levels of co-stimulatory molecules and cytokines, and were both efficient stimulators of T-cells. Our results suggest that mTFF3 does not govern immune responses on the level of DC function.

Gastrin regulates the TFF2 promoter through gastrin-responsive cis-acting elements and multiple signaling pathways

Trefoil family factor 2 (TFF2) is expressed in gastrointestinal epithelial cells where it serves to maintain mucosal integrity and promote epithelial repair. The peptide hormone, gastrin, stimulates acid secretion but also induces proliferation of the acid-secreting mucosa. Because the relationship between these peptides of overlapping function is not understood, we chose to investigate the regulatory effect of gastrin on TFF2 expression. The expression of mRNA and protein of TFF2 was determined by RT-PCR and immunohistochemical staining, respectively. A series of truncated and mutant murine TFF2 promoter constructs was generated. Promoter activity was assessed using dual luciferase reporter assays. Gastrin-responsive DNA-binding sites in the TFF2 promoter were evaluated by electrophoretic mobility shift assay. Gastrin significantly increased the level of endogenous mRNA of TFF2 in the gastrin receptor-expressing AGS-E gastric cancer cell line in a time- and dose-dependent manner. TFF2 protein expression in the gastric fundus was elevated in hypergastrinemic (INS-GAS) transgenic mice and reduced in gastrin-deficient mice. Gastrin treatment increased TFF2 promoter activity through cis-acting regions, containing CCAATA- and GC-rich enhancers. Pretreatment with Y-F476, a gastrin/CCK(B) receptor antagonist, abolished gastrin-dependent promoter activity. Inhibitors of protein kinase C (PKC), mitogen/extracellular signal-regulated kinase (MEK1), and phosphatidylinositol 3-kinase (PI 3-kinase) reduced gastrin-dependent TFF2 promoter activity, whereas an epithelial growth factor receptor (EGFR) inhibitor had no effect. We found that gastrin regulates TFF2 transcription through a GC-rich DNA-binding site and a PKC-, MEK1- and PI 3-kinase-dependent but EGFR-independent pathway. Regulation of TFF2 by gastrin may play a role in the maintenance and repair of the gastrointestinal mucosa.

Analysis of common transforming growth factor beta-1 gene polymorphisms in gastric and duodenal ulcer disease: pilot study

BACKGROUND AND AIM

Transforming growth factor-beta1 (TGF-beta1) has been shown to be an important cytokine that plays a role in cell proliferation, differentiation, tissue injury repair and ulcer healing. The purpose of this pilot study was to investigate if common polymorphisms Leu10Pro, Arg25Pro and C-509T within the TGF-beta1 gene are associated with susceptibility to gastric and duodenal ulcer disease in Russians.

METHOD

Blood samples from 377 unrelated patients with gastric and duodenal ulcer disease and 226 sex- and age-matched healthy controls were used to determine TGF-beta1 gene polymorphisms by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

RESULTS

Leu10Pro substitution in the signal peptide of TGF-beta1 has been found to be associated with susceptibility to gastric ulcer (odds ratio [OR] 1.76, 95% confidence interval [CI] 1.12-2.77). A genotype combination of 10Leu/Leu x 25Arg/Arg x -509C/C was also associated with susceptibility to gastric ulcer disease (OR 1.81, P = 0.01). In addition, the frequency of a combination of genotypes 10Pro/Pro x 25Arg/Pro x -509C/T was statistically lower in patients with duodenal ulcer than in controls (OR 0.42, P = 0.05). A significant difference (P = 0.04) in the distribution of rare haplotypes of the TGF-beta1 gene between patients with duodenal ulcer and healthy controls has been found. Polymorphism Leu10Pro was in positive linkage disequilibrium with C-509T polymorphism (coefficient D = 0.191; P < 0.0001).

CONCLUSIONS

These findings indicate that the Leu10Pro and C-509T polymorphisms may be involved in the modulation of expression of the TGF-beta1 gene, and therefore a predisposition to peptic ulcer disease could be linked to particular alleles of this gene. In particular, a possible role of TGF-beta1 in the pathogenesis of gastric ulcer disease is discussed.

Cellular localization, binding sites, and pharmacologic effects of TFF3 in experimental colitis in mice

Trefoil factors (TFFs) are essential for protection and restitution of the gastrointestinal mucosa but many aspects of TFF biology are unclear. Our aim was to compare the localization of endogenous TFFs and binding sites for injected TFF3 in the colon of healthy and colitic mice and to study the effect of TFF3 on dextrane sulfate sodium (DSS)-induced colitis in mice. Expression of endogenous TFF1-3 was examined by in situ hybridization and immunohistochemistry, and the distribution of intravenously, intraperitoneally, and subcutaneously administered (125)I-TFF3 by autoradiography and gamma-counting. The effect of systemically administered TFF3 on DSS-induced colitis was assessed. We found increased expression of endogenous TFF3 and increased binding of injected (125)I-TFF3 in the colon of animals with DSS-induced colitis. The distribution of intraperitoneally and subcutaneously administered (125)I-TFF3 was comparable. Systemic administration of the peptides reduced the severity of colitis. Expression of endogenous TFF3 and binding of systemically administered TFF3 are increased in DSS-induced colitis. Systemic administration of TFF3 attenuates the disease. These findings suggest a role of TFF3 in mucosal protection.

Allergen induced TFF2 is expressed by mucus-producing airway epithelial cells but is not a major regulator of inflammatory responses in the murine lung

Asthma is a complex pulmonary disorder characterized by reversible airflow obstruction, airway hyperresponsiveness, mucus cell metaplasia, and inflammation. Employing animal models of pulmonary inflammation induced by different allergens and Th2 cytokines, the authors have previously described the up-regulation of trefoil factor 2 (TFF2) in the lung. Given the known biological role of trefoil factors in epithelial restitution, it has been postulated that allergen-induced TFF2 might have an important role in asthmatic responses. Here the authors show that TFF2 is induced early and maintained for 2 weeks following allergen challenge in the mouse lung. In situ mRNA hybridization demonstrated expression of TFF2 primarily in a subset of bronchial epithelial cells and TFF2 immunohistochemistry identified expression in alcian blue-positive bronchial epithelial cells. TFF2 gene-deleted mice inoculated with allergen displayed a 10-fold increase in total cellularity compared with saline controls. Although this response was modestly attenuated compared to wild type controls, the loss of TFF2 did not affect gross levels of tissue inflammation. Furthermore, the loss of TFF2 did not affect induction or resolution of mucus cell metaplasia as measured by periodic acid-Schiff (PAS) or alcian blue staining. Thus, TFF2 is an allergen-induced gene, which is expressed in mucus-positive airways, but is not a major contributor to allergen-induced goblet cell metaplasia, mucus production, or inflammatory responses in the lung.

The effect of EA on the gastric mucosal histology and ITF mRNA expression in stress-induced rats

This study focuses on the effect of electroacupuncture (EA) on the gastric mucosal histology and ITF (intestinal trefoil factor) mRNA in stress-related rat, and the relationship between the gastric protective mechanism of EA at acupoints of Stomach Meridian of Foot-Yangming (SMFY) group and Gallbladder Meridian of Foot-Shaoyang (GMFS) group. Forty rats were randomly divided into 4 groups: blank control group (BCG), model control group (MCG), SMFY group (EA at acupoints of SMFY for 7 days before model inducing), and GMFS group (EA at acupoints of GMFS for 7 days before model inducing). All rats (except normal group) were made model by water immersion and restriction (WRS) on day 7, then the gastric mucosal lesion index (GUI) was accessed, ITF mRNA expression of the tissue was detected by reverse- transcriptase-polymerase chain reaction (RT-PCR) method, and the histological change under light microscope was observed. As a result, the GUI value in SMFY/GMFS groups decreased significantly (p < 0.05 or 0.01). The level of ITF mRNA expression in SMFY group was significantly higher than that in MCG (p < 0.01), while that in GMFS group was higher than MCG but there was no statistical difference (p < 0.05). This result may be due to the intrinsic mechanism of EA's gastric mucosal protection by the upregulation of ITF mRNA expression in gastric mucosal tissue, and the expression variance indicated the classical traditional Chinese medicine (TCM) theory "Relative Particularity between SMFY and Stomach.".

Human pancreatic polypeptide has a marked diurnal rhythm that is affected by ageing and is associated with the gastric TFF2 circadian rhythm

Normal circadian variations in vasoactive intestinal polypeptide, somatostatin, cholecystokinin and pancreatic polypeptide were measured to determine if these alter with aging and to identify gastrointestinal regulatory hormones that might control the dramatic diurnal variation in the gastric cytoprotective trefoil protein TFF2. Plasma pancreatic polypeptide concentrations showed a marked diurnal rhythm (p < 0.0001). Basal and postprandial pancreatic polypeptide concentrations increased with age (p < 0.01). The timing of the diurnal rhythm was consistent with pancreatic polypeptide inhibiting TFF2 secretion and there was a negative association between pancreatic polypeptide and TFF2 concentrations (p < 0.002). The much higher pancreatic polypeptide concentrations in older people will induce increased satiety that may contribute to 'anorexia of ageing'. These results identify potential therapies for treatment of gastric mucosal morbidity and age-associated loss of appetite.

Expression of trefoil factors 1 and 2 in precancerous condition and gastric cancer

AIM: To study the expression of trefoil factor 1 (TFF1) and TFF2 in precancerous condition and gastric cancer and to explore the relationship between TFFs and tumorigenesis, precancerous condition and gastric cancer.

METHODS: The expression of TFF1 and TFF2 was immunohistochemically analyzed in paraffin-embedded samples from 140 patients including 35 cases of chronic superficial gastritis (CSG), 35 cases of gastric ulcer (GU), 35 cases of chronic atrophic gastritis (CAG) and 35 cases of gastric cancer (GC).

RESULTS: TFF1 and TFF2 were located in cytoplasm of gastric mucous cells. In CSG, GU, CAG and GC, the level of TFF1 expression had a decreased tendency (P < 0.05). The expression of TFF2 was higher in GU than in CSG, but the difference was not significant. The expression of TFF2 also had a decreased tendency in GU, CAG, and GC (P < 0.05).

CONCLUSION: The reduced expression of TFF1 and TFF2 in precancerous conditions and gastric cancer may be associated with the proliferation and malignant transformation of gastric mucosa. More investigations are needed to explore the mechanism of TFFs and the relationship between TFFs and gastric cancer.

Altered metaplastic response of waved-2 EGF receptor mutant mice to acute oxyntic atrophy

Metaplastic cell lineages are putative precursors for the development of gastric adenocarcinoma. The loss of parietal cells (oxyntic atrophy) is the initiating step in the evolution of gastric fundic mucosal lineage changes including metaplasia and hyperplasia. However, the intrinsic mucosal factors that promote and modulate the emergence of metaplastic phenotypes remain obscure. Over the past several years, we have studied pharmacologically induced, reversible oxyntic atrophy in rodents treated with DMP-777, a drug that acts as a parietal cell secretory membrane protonophore. DMP-777 elicits a rapid loss of parietal cells followed by the emergence of foveolar hyperplasia and spasmolytic polypeptide (SP)-expressing metaplasia (SPEM). The objective of the present study was to provide further insights into the intrinsic mucosal factors regulating the emergence of SPEM in the setting of oxyntic atrophy. We therefore studied the effects of DMP-777 administration on both SP/trefoil factor (TFF)2-deficient mice, which lack SP/TFF2, a marker of SPEM, and waved-2 mice, which harbor a point mutation in the EGF receptor that attenuates its tyrosine kinase activity. As in wild-type mice, treatment with DMP-777 for 7 days did elicit SPEM in SP/TFF2-deficient mice. These results suggest that SP/TFF2 does not impact on the development of metaplasia after the induction of parietal cell loss. In contrast, waved-2 homozygous mice displayed accelerated SPEM development by 3 days of treatment with DMP-777. These findings indicate that attenuation of EGF receptor signaling in waved-2 mice does elicit a more rapid emergence of SPEM. The results support a role for EGF receptor ligands in the regulation of gastric metaplasia.

Expression of trefoil factor family members correlates with patient prognosis and neoangiogenesis

PURPOSE

Trefoil factor family (TFF) peptides are thought to contribute to epithelial protection and restitution by virtue of their protease-resistant nature and their strong affinity for mucins. However, they are often overexpressed in tumors, where they seem to be negative prognostic factors, possibly contributing to tumor spread, although the precise mechanisms have not been defined.

EXPERIMENTAL DESIGN

Tissue sections from 111 patients with curatively resected advanced gastric carcinoma were immunohistochemically stained for TFF2, ITF (TFF3), and CD34. Microvessel density was expressed as number and area of microvessels. Results were correlated with clinicopathological characteristics and patient survival.

RESULTS

Forty-nine (44.1%) and 41 (36.9%) tumors were immunohistochemically positive for TFF3 and TFF2, respectively. Among the various clinicopathologic variables, overexpression of TFF3 had a significant correlation with patient age only. In addition, a significantly higher prevalence of positive TFF2 staining was detected in large, diffuse tumors and in tumors with lymph node metastasis. The number of microvessels had a significant correlation with both TFF3 and TFF2 staining, whereas the area of microvessels had a significant correlation only with TFF3 staining. Both TFF3 and TFF2 were independent predictors of a worse disease-free survival. TFF3 had a gender-specific negative survival advantage, with a 91.3% disease-free survival in female patients with TFF3-negative advanced gastric carcinoma.

CONCLUSIONS

Induction of increased tumor vascularity might be one of the mechanisms by which TFFs confer metastatic phenotype and frequent disease recurrence in gastric carcinomas. Female patients with TFF3-negative advanced gastric carcinoma have comparable survival as that reported for patients with early gastric carcinoma.

Trefoil factor 2 (TFF2) deficiency in murine digestive tract influences the immune system

BACKGROUND AND AIMS

The gastrointestinal trefoil factor family (TFF1, TFF2, TFF3) peptides are considered to play an important role in maintaining the integrity of the mucosa. The physiological role of TFF2 in the protection of the GI tract was investigated in TFF2 deficiency.

METHODS

TFF2-/- mice were generated and differential expression of various genes was assessed by using a mouse expression microarray, quantitative real time PCR, Northern blots or immunohistochemistry.

RESULTS

On an mRNA level we found 128 differentially expressed genes. We observed modulation of a number of crucial genes involved in innate and adaptive immunity in the TFF2-/- mice. Expression of proteasomal subunits genes (LMP2, LMP7 and PSMB5) involved in the MHC class I presentation pathway were modulated indicating the formation of immunoproteasomes improving antigen presentation. Expression of one subunit of a transporter (TAP1) responsible for importing degraded antigens into ER was increased, similarly to the BAG2 gene that modulates chaperone activity in ER helping proper loading on MHC class I molecules. Several mouse defensin (cryptdin) genes coding important intestinal microbicidal proteins were up-regulated as a consequence of TFF2 deficiency. Normally moderate expression of TFF3 was highly increased in stomach.

Short-chain fatty acid induces intestinal mucosal injury in newborn rats and down-regulates intestinal trefoil factor gene expression in vivo and in vitro

BACKGROUND

Luminal administration of short-chain fatty acids (SCFAs) induces dose-dependent intestinal mucosal injury in newborn rats. However, the mechanism underlying the injurious effects of SCFAs on intestinal mucosa in neonates is unclear. Intestinal trefoil factor (ITF) is a factor important for the maintenance and repair of the intestinal mucosal barrier. Regulation of ITF gene expression by SCFAs may be involved as one of the mechanisms.

OBJECTIVES

To examine the effect of butyrate-induced colonic injury on ITF gene expression in vivo and to determine the molecular mechanisms underlying the butyrate regulation of ITF gene expression in vitro.

METHODS

Whole-section colonic tissues from 9- to 10-day-old Sprague-Dawley rats that have received butyric acid at two different concentrations (150 mmol/L and 300 mmol/L) and for different time periods were processed for total RNA extraction and Northern blot analysis. Littermates that received normal saline or lactic acid at 300 mmol/L served as controls. The effect of butyrate on ITF gene expression was also examined in vitro with human colonic epithelial LS 174T cells. To further define ITF gene regulation by butyrate, transient transfection assays were performed on a 930 bp human ITF promoter-luciferase reporter gene plasmid in LS174T cells with or without the presence of butyrate.

RESULTS

Concurrent with mucosal injury, butyric acid inhibited ITF gene expression in colonic tissues of newborn rats as well as in intestinal epithelial cells in a dose- and time-dependent manner. Furthermore, butyrate reduced ITF promoter report gene activity in transfected LS174T cell, suggesting that butyric acid regulation of ITF gene is by way of a specific ITF promoter.

CONCLUSIONS

Butyric acid induced-intestinal mucosal injury in newborn rats is associated with down-regulation of ITF gene expression. The changes in ITF gene expression in vivo may play a role in the pathogenesis of SCFA-induced intestinal mucosal injury.

The effect of dexamethasone on gastric mucosal changes following sialoadenectomy in rat

In this study, dexamethasone-induced gastric lesions were studied in rats that had undergone sialoadenectomy. The ultrastructural changes developed during the study were detected by electron microscopically, while blood serum and stomach epidermal growth factor (EGF) concentrations were measured by RIA. The result of the study showed that gastric lesions were correlated with gastric mucus secretion and both serum and mucosa EGF levels. After the administration of dexamethasone, it was found that sialoadenectomy significantly (p<0.01) raised the incidence of stomach lesions (p<0.01), and a significant increase in mucus secretion was also found. Additionally, the serum and gastric mucosal EGF levels fell after sialoadenectomy when compared to normal rats. The most important gastric mucosal changes were observed in rats treated with dexamethasone and those both sialoadenectomised and treated with dexamethasone.

TFF3 modulates NF-{kappa}B and a novel negative regulatory molecule of NF-{kappa}B in intestinal epithelial cells via a mechanism distinct from TNF-{alpha}

Trefoil factor 3 (intestinal trefoil factor) is a cytoprotective factor in the gut. Herein we compared the effect of trefoil factor 3 with tumor necrosis factor-alpha on 1) activation of NF-kappaB in intestinal epithelial cells; 2) expression of Twist protein (a molecule essential for downregulation of nuclear factor-kappaB activity in vivo); and 3) production of interleukin-8. We showed that Twist protein is constitutively expressed in intestinal epithelial cells. Tumor necrosis factor-alpha induced persistent degradation of Twist protein in intestinal epithelial cells via a signaling pathway linked to proteasome, which was associated with prolonged activation of NF-kappaB. In contrast to tumor necrosis factor, trefoil factor 3 triggered transient activation of NF-kappaB and prolonged upregulation of Twist protein in intestinal epithelial cells via an ERK kinase-mediated pathway. Unlike tumor necrosis factor-alpha, transient activation of NF-kappaB by trefoil factor 3 is not associated with induction of IL-8 in cells. To examine the role of Twist protein in intestinal epithelial cells, we silenced the Twist expression by siRNA. Our data showed that trefoil factor 3 induced interleukin-8 production after silencing Twist in intestinal epithelial cells. Together, these observations indicated that 1) trefoil factor 3 triggers a diverse signal from tumor necrosis factor-alpha on the activation of NF-kappaB and its associated molecules in intestinal epithelial cells; and 2) trefoil factor 3-induced Twist protein plays an important role in the modulation of inflammatory cytokine production in intestinal epithelial cells.

The diurnal rhythm of the cytoprotective human trefoil protein TFF2 is reduced by factors associated with gastric mucosal damage: ageing, Helicobacter pylori infection, and sleep deprivation

OBJECTIVES

To determine if the normal TFF2 diurnal rhythm is disrupted in those with increased risk of gastric morbidity. Trefoil proteins protect the gastrointestinal mucosa from damage and aid its repair. TFF2 is considered the major cytoprotective gastric trefoil protein. There is a marked circadian variation in gastric luminal TFF2 in young healthy volunteers with peak levels present during the night.

METHODS

Gastric juice was aspirated at two hourly intervals over a 24-h period via a nasogastric tube. TFF2 was measured by quantitative western transfer analysis. Helicobacter pylori (H. pylori) status was measured by C13 urea breath test and by serology. The effects of H. pylori infection, sleep deprivation, and ageing, which cause increased gastric morbidity, on the TFF2 circadian rhythm were tested.

RESULTS

H. pylori infection attenuated the increase in TFF2 that occurs during the night. The TFF2 diurnal rhythm was reduced in older people and both the TFF2 level reached and the time at which the maximum TFF2 concentration occurs were associated inversely with age (p < 0.005). Sleep deprivation delayed the normal night time increase in gastric TFF2 and resulted in an overall reduction in TFF2 secretion.

CONCLUSIONS

H. pylori infection, ageing, and sleep deprivation cause a reduction in the TFF2 diurnal rhythm. The demonstration that the TFF2 rhythm is impaired in cohorts of individuals known to suffer gastric symptoms suggests that interventions to restore the normal TFF2 rhythm in those with poor mucosal protection could reduce morbidity.

ExQuest, a novel method for displaying quantitative gene expression from ESTs

There is a pressing need for interactive bioinformatics tools that empower investigators with the means to extract information and organize it in a simplified but meaningful format. A wealth of mammalian gene expression data is readily accessible, much of which is based on expressed sequence tags (ESTs). Many mammalian ESTs are derived from tissue-specific cDNA libraries in which the number of ESTs representing a specific gene approximates the transcriptional expression level in the source tissue. Our program ExQuest (Expressional Quantification of ESTs) organizes the public EST database (dbEST) into hierarchical tissue classes and reports tissue or developmental gene expression patterns for both mRNA and genomic sequences. ExQuest also displays tissue expression patterns of genes in the context of assembled chromosomes. These interactive "transcriptome" maps provide a novel tool for investigating the genomic basis of gene expression as well as prioritizing candidate genes within genetically mapped mutant and quantitative trait loci.

Cyclooxygenase 2, pS2, inducible nitric oxide synthase and transforming growth factor alpha in gastric adaptation to stress

AIM

To determine the role of mucosal gene expression of cyclooxygenase 2 (COX-2), pS2 (belongs to trefoil peptides), inducible nitric oxide synthase (iNOS) and transforming growth factor alpha (TGFalpha) in gastric adaptation to water immersion and restraint stress (WRS) in rats.

METHODS

Wistar rats were exposed to single or repeated WRS for 4 h every other day for up to 6 d. Gastric mucosal blood flow (GMBF) was measured by laser Doppler flowmeter-3. The extent of gastric mucosal lesions were evaluated grossly and histologically and expressions of COX-2, pS2,iNOS and TGFalpha were determined by reverse transcriptase polymerase chain reaction (RT-PCR) and Western blot.

RESULTS

The damage to the surface of gastric epithelium with focal areas of deep haemorrhagic necrosis was induced by repeated WRS. The adaptative cytoprotection against stress was developed with activation of cell proliferation in the neck regions of gastric glands. The ulcer index (UI) in groups II, III and IV was markedly reduced as compared with group I (I: 47.23+/-1.20; IV: 10.39+/-1.18,P<0.01). GMBF significantly decreased after first exposure to WRS with an adaptive increasement of GMBF in experimental groups after repetitive challenges with WRS. After the 4th WRS, the value of GMBF almost restored to normal level (I: 321.87+/-8.85; IV: 455.95+/-11.81, P<0.01). First WRS significantly decreased the expression of pS2 and significantly increased the expressions of COX-2, iNOS and TGFalpha. After repeated WRS, pS2 and TGFalpha expressions gradually increased (pS2: I: 0.37+/-0.02; IV: 0.77+/-0.01; TGFalpha: I: 0.86+/-0.01; IV: 0.93+/-0.03, P<0.05) with a decrease in the expressions of COX-2 and iNOS (COX-2: I: 0.45+/-0.02; IV: 0.22+/-0.01; iNOS: I: 0.93+/-0.01; IV: 0.56+/-0.01, P<0.01). Expressions of pS2, COX-2, iNOS and TGFalpha showed regular changes with a good relationship among them.

CONCLUSION

Gastric adaptation to WRS injury involves enhanced cell proliferation, increased expression of pS2 and TGFalpha, and reduced expression of COX-2 and iNOS. These changes play an important role in adaptation of gastric mucosa after repeated WRS.

Trefoil factor family peptide 3 prevents the development and promotes healing of ischemia-reperfusion injury in weanling rats

BACKGROUND/PURPOSE

Although the pathogenesis of necrotizing enterocolitis (NEC) is not completely defined, ischemia appears to be one of the most important causative factors. Trefoil factor family peptide 3 (TFF3) is a peptide normally expressed in the small bowel and colon and is involved in the maintenance and repair of mucosal integrity. The authors hypothesized that monomeric (TFF3 Ser57) and dimeric (TFF3 Cys57) recombinant TFF3 may prevent the development and accelerate healing of intestinal ischemia-reperfusion injury in weanling rats.

METHODS

Intestinal injury was induced in 18-day-old rats by occlusion of the superior mesenteric vessels for 60 minutes. To examine the protective effect, rats were given 3 microg/g of TFF3 Ser57 or TFF3 Cys57 by subcutaneous or enteral administration 30 minutes before the vascular occlusion. To examine the healing effect, rats were given 3 microg/g of TFF3 Ser57 or TFF3 Cys57 by subcutaneous or enteral administration 60 minutes after the beginning of reperfusion. Samples from small bowel and colon were collected for morphometric analysis after 3 hours of reperfusion. Mucosal damage was assessed by the Chiu score.

RESULTS

Both forms of TFF3 reduced the amount of damage when administered before the ischemia. Administration of TFF3 Ser57 and TFF3 Cys57 after the beginning of reperfusion significantly increased the villous height and decreased the Chiu score in the small intestine and colon.

CONCLUSIONS

TFF3 Ser57 monomer and TFF3 Cys57 dimer prevent the development and promote healing of ischemia-reperfusion injury in weanling rats. There are no differences between the routes of administration of TFF3.

Immunoassays of human trefoil factors 1 and 2: measured on serum from patients with inflammatory bowel disease

BACKGROUND

The trefoil factors (TFF1-3) are cysteine-rich peptides expressed in the gastrointestinal tract where they play a critical role in mucosal protection and repair. The expression is up-regulated at sites of ulceration in various chronic inflammatory diseases. Recently, we presented an ELISA method for measurement of TFF3. The aims of the present study were to develop and evaluate ELISAs for the other two known human trefoil peptides, TFF1 and TFF2, and to carry out a cross-sectional study on serum TFF levels in patients with inflammatory bowel disease (IBD).

METHODS

The TFF1-ELISA was based on two polyclonal rabbit antibodies and the TFF2-ELISA on a monoclonal mouse antibody and a polyclonal rabbit antibody. RhTFF1 and 2 were employed to prepare the calibrators. TFF1-3 were assayed in serum from IBD patients (n=41) and controls (n=13).

RESULTS

The TFF1- (TFF2-) ELISA had a detection limit of 3 pmol/L (6 pmol/L) and an analytical imprecision (CV(A)) of 7.0-8.8 for mean concentrations of 24-120 pmol/L (6.1-8.0 for mean concentrations of 17-77 pmol/L). The central reference intervals (n=300) were 140-1400 pmol/L (37-190 pmol/L). There was no variation with age and menstrual cycle. Food intake reduced concentrations of TFF1 by approximately 15%, but did not influence concentrations of TFF2. TFF1 and TFF3 were increased in serum from IBD patients.

CONCLUSIONS

We have developed assays for measuring TFF1 and TFF2. Finding increased TFF concentrations in serum from IBD patients suggests that measurements of trefoil peptides may be of clinical relevance in IBD.

Regeneration of gastric mucosa during ulcer healing follows pathways that correspond to the ontogenetic course of rat fundic glands

Gastric ulcers in humans are notoriously chronic and recurring lesions. Although the average individual who undergoes no treatments requires many years for healing, most studies on the healing process of the experimentally induced ulcers have mainly focused on the early stages. Natural history of the ulcer healing has not been completely revealed. We have undertaken long-term investigation up to the 150th day after the cryo-injury to shed light on the natural history of the ulcer healing process compared with developmental changes of postnatal fundic glands. By the 30th day, restitutive gastric glands were mostly seen to cover the ulcer lesions, where well-developed gland-type mucous cells, showing Griffonia simplicifolia agglutinin (GSA)-II labeling, appeared to occupy the basal portion. Most of the bromodeoxyuridine-labeled cells were superimposed on the GSA-II-positive cell zone, forming the proliferative zone. By the 150th day, the restitutive glands were complete, with all epithelial components and topology of the normal fundic glands. The process of the ulcer healing was quite compatible with the developmental changes of the postnatal fundic glands. These results imply that the regeneration of gastric epithelium during the ulcer healing follows pathways linked to the ontogenetic course of the fundic gland.

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.

TFF2 (trefoil family factor2) inhibits apoptosis in breast and colorectal cancer cell lines

We have recently demonstrated that human TFF2 inhibits apoptosis in the non-TFF2 expressing breast adenocarcinoma cell line MCF-7. In this study we examined the impact of TFF2 and an anti-TFF2 antibody (hSP3) on the survival of other human adenocarcinoma cell lines; TFF2-positive (LS174T and SW480) and TFF2-negative (MCF-7 and T47D). Addition of TFF2 protected the (TFF2-) lines but had no effect on those constitutively expressing TFF2. Blocking with hSP3 significantly increased apoptosis in the (TFF2+) cell lines with minimal effect on the (TFF2-) cells. Our results show that the cytoprotective effect of TFF2 seen in MCF-7 cells is not cell line-specific and can be abrogated by inhibition of its expression.