Characterization of human and rat intestinal trefoil factor produced in yeast

Serum Trefoil Factor-3 Predicts Survival in Peripheral Artery Disease

Trefoil factor 3 (TFF3) has been studied in processes leading to atherosclerosis. Data are scarce in manifest disease and missing in peripheral artery disease (PAD). This study aims to elucidate TFF3 with disease stages, degrees of atherosclerosis, and outcomes. TFF3 was measured in serum in 364 PAD patients without critical limb ischemia and mild to moderate chronic kidney disease (CKD). Mortality data were retrieved from the Austrian central death registry (median observation 9.6 years). Survival analyses were performed using Cox regression and the Kaplan-Meier method. A negative association between ankle-brachial index and TFF3 (P < .001) was observed, while levels were similar in asymptomatic and symptomatic PAD. TFF3 increased with history of cardiovascular and cerebrovascular disease (P < .001). TTF3 was associated with the estimated glomerular filtration rate (R = -0.617, P < .001) and urinary albumin-creatinine ratio (R = 0.229, P < .001). One SD increase in TFF3 showed a worsening in all-cause mortality (hazard ratio 1.68, CI 1.37-2.05) which persisted after multiple adjustment for cardiovascular risk, inflammatory, and angiogenetic markers (hazard ratio 1.35, CI 1.01-1.81). This study is the first to link TFF3 with both disease markers and outcomes in PAD. TFF3 demonstrated associations with renal function, PAD severity measured by ankle-brachial index, and additional atherosclerotic burden in PAD.

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.

The expression of P2Y6 receptor promotes the quality of mucus in colitic mice

In the intestine, mucins are expressed and secreted by goblet cells and enterocytes in a constitutive manner and in response to secretagogues to form a protective mucus layer. This protective barrier is often lost in inflammatory bowel disease (IBD). Interestingly, extracellular nucleotides, through P2Y receptors, were identified as mucin secretagogues in mucinous epithelia. These nucleotides are found in the intestine's extracellular milieu under basal conditions and in higher concentrations in pathologies such as IBD. It was observed that the mucus layer was affected in P2ry6 knockout mice suffering from dextran sodium sulfate (DSS)-induced colitis. P2ry6^-/- mice were more sensitive to DSS-induced colitis, resulting in larger ulcers and increased disease activity index. Interestingly, the absence of P2Y₆ receptor expression negatively affected the mucus quality, as shown by a reduction in sulfomucin staining and the absence of a dense internal fucosylated mucin layer in P2ry6^-/- mice. Hence, we cannot rule out that the absence of P2Y₆ receptors in knockout animals could negatively impact mucin secretion. However, we did not measure a reduction in the number of goblet cells, as previously reported. Instead, the results suggest that goblet cells rapidly discharged mucins to compensate for the mucus layer's increased lability, which resulted in empty goblet cells that are less visible to mucin staining. This study's results, along with previous reports, point toward a protective role for the P2Y₆ receptor in IBD.

Chemical synthesis of human trefoil factor 1 (TFF1) and its homodimer provides novel insights into their mechanisms of action

TFF1 is a key peptide for gastrointestinal protection and repair. Its molecular mechanism of action remains poorly understood with synthetic intractability a recognised bottleneck. Here we describe the synthesis of TFF1 and its homodimer and their interactions with mucins and Helicobacter pylori. Synthetic access to TFF1 is an important milestone for probe and therapeutic development.

Effect of Initial Periodontal Therapy on Salivary Trefoil Factor (TFF3) in otherwise Healthy Patients with Gingivitis and Chronic Periodontitis

Background:

The search for an ideal biomarker which can determine the current disease status that predicts the sites and individuals with increased susceptibility to periodontal disease has been going on since a long time. One such group of molecules which have been investigated recently are the trefoil factors, and the present study aims to determine the role of salivary trefoil factor 3 (TFF3) in periodontitis and gingivitis patients.

Materials and Methods:

A total of fifty participants, of which 25 were diagnosed with moderate-to-severe periodontitis and 25 with chronic gingivitis were included in the study. The routine periodontal parameters were recorded at baseline and at 6 weeks which included plaque index, gingival index, bleeding index, probing depth, and clinical attachment level. The saliva samples were collected from both the groups at baseline and 6 weeks after nonsurgical periodontal therapy and analyzed by enzyme-linked immunosorbent assay to estimate the concentration of trefoil factor 3.

Results:

All the periodontal parameters improved at 6-week reevaluation in both the groups. There was a significant change in the TFF3 levels in the periodontitis group from baseline to 6 weeks, and the concentrations were found to be higher following nonsurgical therapy, whereas the quantum of change in the gingivitis group was negligible. The levels of TFF3 remained unchanged in those periodontitis participants who required surgical intervention at the 6^th-week reevaluation.

Conclusion:

The estimation of TFF3 levels may aid in decision-making in the treatment strategy of patients with moderate-to-severe periodontitis.

Trefoil factor 3 in perinatal pancreas is increased by gestational low protein diet and associated with accelerated β-cell maturation

The endocrine pancreas expands markedly in the first postnatal days and the insulin producing β-cells initiate a functional maturation preceded by a morphological change of the islets of Langerhans. Trefoil factor 3 (TFF3) is a secreted peptide expressed in intestinal epithelia, where it promotes migration, but its role in the pancreas is not characterized. The aim of this study was to examine the expression and function of TFF3 in perinatal rat pancreas, ex vivo cultured fetal rat pancreas and in the rat β-cell line INS-1E. Control or gestational low-protein diet perinatal rat pancreas was harvested at embryonic day 20 (E20), day of birth (P0) and postnatal day 2 (P2). TFF3 mRNA was upregulated 4.5-fold at P0 vs. E20 and downregulated again at P2. In protein-undernourished pups induction of TFF3 at P0 was further increased to 9.7-fold and was increased at P2. TFF3 caused tyrosine phosphorylation of EGFR in INS-1E β-cells, and purified recombinant TFF3 increased both attachment and spreading of INS-1E β-cells. In ex vivo cultures of collagenase digested fetal rat pancreas, a model of perinatal β-cell maturation, TFF3 increased cellular spreading as well as insulin mRNA levels. TFF3 also increased the expression of Pref1/Dlk1 that shares similarities in expression and regulation with TFF3. These results suggest that TFF3 may promote adhesion and spreading of cells to accelerate β-cell maturation. This study indicates a functional role for TFF3 in pancreatic β-cell maturation in the perinatal period, which is altered by low protein diet during gestation.

Production of Monoclonal Antibodies against Human Trefoil Factor 3 and Development of a Modified-Sandwich ELISA for Detection of Trefoil Factor 3 Homodimer in Saliva

Background

Human trefoil factor (TFF) peptides consist of three members: TFF1, TFF2 and TFF3. TFF3 is the most abundant TFF peptide in saliva. TFF3 homodimer was suggested to be involved in apoptosis inhibition and malignancy. Determination of TFF3 homodimer expression profiles in saliva may lead to new information about oral biology and diseases. The objective of this study was to generate monoclonal antibodies (mAbs) against TFF3 and apply the produced mAbs for the establishment of ELISA for quantification of dimeric TFF3 in saliva.

Results

With our modified hybridoma technique, three hybridoma clones producing anti-TFF3 mAbs having IgG isotype were generated. The mAbs were specific for TFF3 with no cross-reactivity to other TFFs. Using the generated mAbs, a modified-sandwich ELISA with high sensitivity for the quantification of dimeric TFF3 in saliva was developed. Using this ELISA, the amount of dimeric TFF3 in saliva could be measured.

Conclusions

A modified-sandwich ELISA for the quantification of TFF3 dimeric form was established. The established ELISA will be a valuable tool for facilitating the investigation of the physiological roles and the diagnostic values of TFF3 in oral diseases. The concept of this modified-sandwich ELISA may be applied for the determination of other homodimeric peptides of interest.

Trefoil factor 3 contributes to the malignancy of glioma via regulating HIF-1α

Trefoil factor 3 (TFF3) plays significant roles in several solid tumors. However, the expression pattern and function of TFF3 in glioblastoma (GBM) have not been reported. Here, we report that expression level of TFF3 significantly elevated in glioma and correlated with the prognosis of glioma patients. Then we found TFF3 promotes proliferation, invasion, and migration and inhibits apoptosis of glioma cells in vitro, and delayed tumor progression in subcutaneous xenograft nude mice, and prolonged the median survival time in orthotopic xenograft mice. Moreover, knockdown of TFF3 reduced the expression of HIF-1α through a hypoxia-independent manner. These findings suggest that targeting TFF3 may offer a novel strategy for therapeutic intervention of malignant gliomas.

TFF3 Expression as Stratification Marker in Borderline Epithelial Tumors of the Ovary

Borderline tumors (BOT) of the ovary account for 10% to 20% of ovarian neoplasms. Like ovarian cancer, BOT encompass several different histological subtypes (serous, mucinous, endometrioid, clear cell, transitional cell and mixed) with serous (SBOT) and mucinous (MBOT) the most common. Current hypotheses suggest low-grade serous carcinoma may develop in a stepwise fashion from SBOT whereas the majority of high grade serous carcinomas develop rapidly presumably from inclusion cysts or ovarian surface epithelium. The pathogenesis of mucinous ovarian tumors is still puzzling. Molecular markers could help to better define relationships between such entities. Trefoil factor-3 (TFF3) is an estrogen-regulated gene associated with prognosis in different types of cancer. It has also been included in a recent marker panel predicting subtypes of ovarian carcinoma. We analyzed the expression of TFF3 by immunohistochemistry in a cohort of 137 BOT and its association with histopathological features. Overall expression rate of TFF3 was 21.9%. None of the BOT with serous and endometrioid histology displayed strong TFF3 expression. On the other hand, TFF3 was highly expressed in 61.4% of MBOT cases and 33.3% of BOT with mixed histology (P < 0.001) suggesting a potential function of the protein in that subtypes. Associations of TFF3 expression with FIGO stage and micropapillary pattern were significant in the overall cohort but confounded by their correlation with histological subtypes. The highly specific expression of TFF3 in MBOT may help to further clarify potential relationships of tumors with mucinous histology and warrants further studies.

Trefoil factor 3 as a novel biomarker to distinguish between adenocarcinoma and squamous cell carcinoma

In carcinoma, such as of the lung, the histological subtype is important to select an appropriate therapeutic strategy for patients. However, carcinomas with poor differentiation cannot always be distinguished on the basis of morphology alone nor on clinical findings. Hence, delineation of poorly differentiated adenocarcinoma and squamous cell carcinoma, the 2 most common epithelial-origin carcinomas, is pivotal for selection of optimum therapy. Herein, we explored the potential utility of trefoil factor 3 (TFF3) as a biomarker for primary lung adenocarcinoma and extrapulmonary adenocarcinomas derived from different organs. We observed that 90.9% of lung adenocarcinomas were TFF3-positive, whereas no expression of TFF3 was observed in squamous cell carcinomas. The subtype of lung carcinoma was confirmed by four established biomarkers, cytokeratin 7 and thyroid transcription factor 1 for adenocarcinoma and P63 and cytokeratin 5/6 for squamous cell carcinoma. Furthermore, expression of TFF3 mRNA was observed by quantitative PCR in all of 11 human lung adenocarcinoma cell lines and highly correlated with markers of the adenocarcinomatous lineage. In contrast, little or no expression of TFF3 was observed in 4 lung squamous cell carcinoma cell lines. By use of forced expression, or siRNA-mediated depletion of TFF3, we determined that TFF3 appeared to maintain rather than promote glandular differentiation of lung carcinoma cells. In addition, TFF3 expression was also determined in adenocarcinomas from colorectum, stomach, cervix, esophagus, and larynx. Among all these extrapulmonary carcinomas, 93.7% of adenocarcinomas exhibited TFF3 positivity, whereas only 2.9% of squamous cell carcinomas were TFF3-positive. Totally, 92.9% of both pulmonary and extrapulmonary adenocarcinomas exhibited TFF3 positivity, whereas only 1.5% of squamous cell carcinomas were TFF3-positive. In conclusion, TFF3 is preferentially expressed in adenocarcinoma and may function as an additional biomarker for distinguishing adenocarcinoma from squamous cell carcinoma.

Generation of Lactococcus lactis capable of coexpressing epidermal growth factor and trefoil factor to enhance in vitro wound healing

Epidermal growth factor (EGF) and trefoil factor 3 (TFF3) are peptides that actively support the restitution and repair of mucosal epithelial barriers. Previous studies have shown that TFF3 enhanced EGF effect in wound healing, suggesting that the combined application of the two factors may be advantageous in clinical tissue repair. Expression of multiple proteins in a single host is a desirable approach in a biotechnological process, allowing to reduce cost and increase production efficiency. The aim of the present study was to study the feasibility of coexpressing EGF and TFF3 in food grade bacteria, Lactococcus lactis (L. lactis). Using an expression construct allowing simultaneous translation of two separate recombinant peptides, we generated a L. lactis that coexpressed and secreted EGF and TFF3 dually (LL-ET). Western blot analysis revealed that LL-ET secreted 45-54 % more total recombinant peptides (EGF+TFF3) per flask fermentation and 21-37 % more total recombinant proteins in bioreactor fermentation compared to their single factor expressing L. lactis counterparts (LL-EGF and LL-TFF3, respectively). The resulted recombinant EGF and TFF3 showed enhancement in wound healing activity in vitro. Our data suggest that the dual expression and secretion of EGF and TFF3 by L. lactis effectively accelerated cell migration, demonstrating potential future oral application of L. lactis fermentation product containing dual factors or a cocktail of factors to potentially treat intestinal damage and inflammation.

Enhanced antidepressant-like effects of the macromolecule trefoil factor 3 by loading into negatively charged liposomes

Immunocytes, mainly neutrophils and monocytes, exhibit an intrinsic homing property, enabling them to migrate to sites of injury and inflammation. They can thus act as Trojan horses carrying concealed drug cargoes while migrating across impermeable barriers to sites of disease, especially the blood–brain barrier (BBB). In this study, to target circulating phagocytic cells, we formulated negatively charged nanosize liposomes and loaded trefoil factor 3 (TFF3) into liposomes by the pH-gradient method. According to the optimized formulation (5:1.5 of lipid to cholesterol, 10:1 of lipid to drug, 10 mg/mL of lipid concentration, and 10 mmol/L of phosphate-buffered saline), 44.47% entrapment efficiency was obtained for TFF3 liposomes with 129.6 nm particle size and −36.6 mV zeta potential. Compared with neutrally charged liposomes, the negatively charged liposomes showed a strong binding capacity with monocytes and were effectively carried by monocytes to cross the BBB in vitro. Furthermore, enhanced antidepressant-like effects were found in the tail-suspension and forced-swim tests in mice, as measured by decreased immobility time, as well as increased swimming time and reduced immobility in rats. These results suggested that negatively charged liposomes could improve the behavioral responses of TFF3, and our study opens up a new way for the development of effective therapies for brain disease by increasing the permeability of the BBB.

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.

Expression and localization of trefoil factor family genes in rat submandibular glands

The trefoil factor (TFF) family, which comprises TFF1, TFF2 and TFF3, plays an essential role in epithelial regeneration within the gastrointestinal tract. All three TFFs are present in human saliva; TFF3 is the predominant trefoil peptide. Little is known about the expression and tissue distribution of TFFs in rats, which are commonly used as a model system for human studies. We investigated the localization of the TFF genes that encode secretory peptides in rat submandibular glands (SMG). All three TFFs were expressed in rat SMG, although their location varied. Substantial amounts of TFF1 were detected only in the cytoplasm of epithelial cells in the SMG granular convoluted tubules (GCT), while TFF2 and TFF3 were widely distributed in the cytoplasm of epithelial cells of intercalated ducts (ID), striated ducts (SD) and interlobular ducts (ILD). The three TFFs also were detected especially in the lumens of the SD and ILD. Semi-quantitative RT-PCR and in situ hybridization experiments confirmed TFF1, TFF2 and TFF3 mRNA expressions in the SMG. Greater expression of TFF peptides and mRNA was observed in male rats than in females. The broad expression of TFFs in rat SMG cells and lumens suggests that TFFs function in this organ by their secretion into the duct lumens. We also found differences in TFF expression profiles between rat and human SMG; therefore, caution should be exercised when using rats as a model for human TFF studies.

Tff3, as a novel peptide, regulates hepatic glucose metabolism

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder strongly associated with hepatic glucose intolerance and insulin resistance. The trefoil peptides are a family of small regulatory proteins and Tff3 is widely expressed in multiple tissues including liver. But the roles of Tff3 in regulation of glucose metabolism and insulin sensitivity in liver remain unclear. Here we show that the hepatic Tff3 expression levels were decreased in ob/ob and high-fat diet-induced obese mice. Overexpression of Tff3 in primary mouse hepatocytes inhibited the expression of gluconeogenic genes, including G6pc, PEPCK and PGC-1α, subsequently decreasing cellular glucose output. GTT and ITT experiments revealed that adenovirus-mediated overexpression of Tff3 in diabetic or obese mice improved glucose tolerance and insulin sensitivity. Collectively, our results indicated that Tff3 peptides are involved in glucose homeostasis and insulin sensitivity, providing a promising peptide on new therapies against the metabolic disorders associated with T2DM.

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.

Validation of commercial assays for measurements of trefoil factor family peptides in serum

BACKGROUND

Trefoil peptides (TFF1, TFF2 and TFF3) are 7-12 kDa molecules, secreted by mucin-producing epithelial cells. Increased serum concentrations have been reported in a number of pathological conditions, which warrants the need for validated commercially available assays.

METHODS

We validated commercial assays for TFF1-3 and compared results obtained with our in-house assays, using serum from blood donors.

RESULTS

Level of detection was: ≤ 0.008 nmol/L. Measuring ranges were: 0.032-0.51 (TFF1), 0.038-0.76 (TFF2) and 0.019-0.15 (TFF3) nmol/L. Imprecision (CV), judged from the measurement of serum pools in two levels, was below 9% (TFF2 and TFF3) but up to 18% (mean 0.41 nmol/L) for TFF1. No cross reactivity between the TFFs (concentrations > 100 nmol/L) was observed. The 95% non-parametric reference intervals were: <0.0032-0.53 (TFF1), 0.099-1.4 (TFF2) and 0.086-0.87 (TFF3) nmol/L. Comparing commercial to in-house assays (n=132), showed biases explained by differences in the calibrators (TFF1 and TFF2). A number of samples showed markedly different results.

CONCLUSIONS

The commercial assays for TFF2 and TFF3 are acceptable for use on serum samples, while the TFF1 assay revealed a poor imprecision and a too narrow measuring range. Results obtained with the commercial and the in-house assays differed, partly because of differences in the calibrators employed.

Trefoil factor 2 requires Na/H exchanger 2 activity to enhance mouse gastric epithelial repair

Trefoil factor (TFF) peptides are pivotal for gastric restitution after surface epithelial damage, but TFF cellular targets that promote cell migration are poorly understood. Conversely, Na/H exchangers (NHE) are often implicated in cellular migration but have a controversial role in gastric restitution. Using intravital microscopy to create microscopic lesions in the mouse gastric surface epithelium and directly measure epithelial restitution, we evaluated whether TFFs and NHE isoforms share a common pathway to promote epithelial repair. Blocking Na/H exchange (luminal 10 μm 5-(N-ethyl-N-isopropyl) amiloride or 25 μm HOE694) slows restitution 72-83% in wild-type or NHE1(-/-) mice. In contrast, HOE694 has no effect on the intrinsically defective gastric restitution in NHE2(-/-) mice or TFF2(-/-) mice. In TFF2(-/-) mice, NHE2 protein is reduced 23%, NHE2 remains localized to apical membranes of surface epithelium, and NHE1 protein amount or localization is unchanged. The action of topical rat TFF3 to accelerate restitution in TFF2(-/-) mice was inhibited by AMD3100 (CXCR4 receptor antagonist). Furthermore, rat TFF3 did not rescue restitution when NHE2 was inhibited [TFF2(-/-) mice +HOE694, or NHE2(-/-) mice]. HOE694 had no effect on pH at the juxtamucosal surface before or after damage. We conclude that functional NHE2, but not NHE1, is essential for mouse gastric epithelial restitution and that TFFs activate epithelial repair via NHE2.

Protein kinase C iota in the intestinal epithelium protects against dextran sodium sulfate-induced colitis

BACKGROUND

The integrity of the intestinal epithelium is critical for the absorption and retention of fluid and nutrients. The intestinal epithelium also provides a barrier between the intestinal bacteria and the body's immune surveillance. Therefore, intestinal epithelial barrier function is critically important, and disruption of the intestinal epithelium results in rapid repair of the damaged area.

METHODS

We evaluated the requirement for protein kinase C iota (PKCι) in intestinal epithelial homeostasis and response to epithelial damage using a well-characterized mouse model of colitis. Mice were analyzed for the clinical, histological, and cellular effects of dextran sodium sulfate (DSS) treatment.

RESULTS

Knockout of the mouse PKCι gene (Prkci) in the intestinal epithelium (Prkci KO mice) had no effect on normal colonic homeostasis; however, Prkci KO mice were significantly more sensitive to DSS-induced colitis and death. After withdrawal of DSS, Prkci KO mice exhibited a continued increase in apoptosis, inflammation, and damage to the intestinal microvasculature and a progressive loss of trefoil factor 3 (TFF3) expression, a regulatory peptide important for intestinal wound healing. Knockdown of PKCι expression in HT-29 cells reduced wound healing and TFF3 expression, while addition of exogenous TFF3 restored wound healing in PKCι-depleted cells.

CONCLUSIONS

Expression of PKCι in the intestinal epithelium protects against DSS-induced colitis. Our data suggest that PKCι reduces DSS-induced damage by promoting intestinal epithelial wound healing through the control of TFF3 expression.

Expression of trefoil factor family-3 and β-catenin in different types of colorectal mucosal lesions

AIM: To analyze the expression of trefoil factor family-3 (TFF3) and β-catenin in different types of colorectal mucosal lesions and to explore their role in the development and progression of colorectal adenocarcinoma and adenoma.

METHODS: The expression of TFF3 and β-catenin was detected by immunohistochemistry in 20 normal colorectal mucosa specimens, 30 colorectal polyp specimens, 20 colorectal adenoma (CRA) specimens, 20 colorectal adenoma (with atypical hyperplasia, CRAAH) specimens, and 40 colorectal adenocarcinoma (CRCA) specimens. The differences in the expression of TFF3 and β-catenin in different types of colorectal mucosal lesions were compared.

RESULTS: The positive rate of TFF3 expression was significantly lower in CRA and CRAAH (P < 0.05), but higher in CRCA. The abnormal expression of β-catenin were gradually increasing along with the sequence of CRA→CRAAH→CRAC, the membrane expressing deletion and ectopic expression were both higher in CRAC than in CRCP and CRA (60.00% vs 0.00%, 15.00%; 75.00% vs 0.00%, 40.00%, all P < 0.05). TFF3 expression was not correlated with tumor location or differentiation in CRAC, but was related to lymph node metastasis and Duke's stage (both P < 0.05). β-catenin expression was not correlated with tumor location or lymph node metastasis, but was related to tumor differentiation. Ectopic expression of β-catenin was related to Duke's stage (P < 0.05). There were significantly positive correlations between TFF3 expression and abnormal expression and loss of membrane expression of β-catenin in CRA (r = 0.427, P = 0.006; r = 0.577, P = 0.000) but not in CRAC (r = 0.015, P = 0.951; r = 0.385, P = 0.094). There was a significantly positive correlation between loss of membrane expression and ectopic expression of β-catenin in CRAC and CRA (r = 0.638, P = 0.000; r = 0.514, P = 0.020).

CONCLUSION: The expression of TFF3 and β-catenin is closely related with the development and progression of CRAC. They may be involved in an early event in colorectal carcinogenesis. TFF3 is related to the abnormal expression of β-catenin, both of which may be involved in the development and progression of CRAC.

Trefoil factor family peptides in human saliva and cyclical cervical mucus. Method evaluation and results on healthy individuals

BACKGROUND

Trefoil peptides are 7-12 kDa molecules, se-creted by a variety of mucin-producing epithelial cells from different tissues and believed to be essential for protection and maintenance of gastrointestinal mucosa. Data on concentrations of trefoil peptides in secretions are limited.

METHODS

We validated in-house ELISA assays, developed for measurement of trefoil peptide concentrations (TFF1, TFF2 and TFF3) in serum, for use with saliva and cervical mucus. Saliva from healthy individuals (n=30), and cervical mucus as well as blood collected three times during the menstrual cycle from healthy women (n=18) were analyzed.

RESULTS

Recovery of all trefoil peptides in the initial supernatants of saliva and (cervical mucus) were 86 and (92)% or more. Recovery of exogenously added trefoil peptides was 93 and (95)% or more. Western blotting showed that antibodies used in the TFF3-ELISA assay recognised one molecule of the same size as TFF3 in both saliva and cervical mucus. Median concentrations of TFF1, TFF2 and TFF3 in saliva and (cervical mucus) were 2.7 (2.7), 0.08 (0.58) and 14 (430) nmol/g protein, with a significant decrease in concentrations in cervical mucus after ovulation. Serum concentrations resembled previously measured values in blood donors and showed no cyclic change.

CONCLUSIONS

Previously established ELISA assays can be employed for measurement of trefoil peptides in saliva and cervical mucus. TFF3 was the predominant trefoil peptide in both saliva and cervical mucus, and TFF3 in cervical mucus represents the highest concentration measured in a biological fluid to date.

Human intestinal TFF3 forms disulfide-linked heteromers with the mucus-associated FCGBP protein and is released by hydrogen sulfide

TFF3 is a secretory peptide belonging to the trefoil factor family with a predicted size of 59 amino acid residues containing seven cysteine residues. It is predominantly expressed in intestinal goblet cells where it plays a key role in mucosal regeneration and repair processes. In the course of these studies, human colonic TFF3 was shown to exist mainly as a high molecular weight heteromer. Purification of this heteromer and characterization by LC-ESI-MS/MS analysis identified the IgG Fc binding protein (FCGBP) as the disulfide-linked partner protein of TFF3. FCGBP is a constituent of intestinal mucus secreted by goblet cells. Furthermore, low amounts of TFF3/monomer and only little TFF3/dimer were detected in human colonic extracts. Here, we show that these TFF3 forms can be released from the purified TFF3-FCGBP heteromer complex in vitro by reduction with hydrogen sulfide (H(2)S). Such a mechanism would be in line with the high H(2)S concentrations reported to occur in the lumen of the colon. Of special note, this points to intestinal mucus as a reservoir for a biologically active peptide. Also proteolytic processing of FCGBP was observed which is in line with multiple autocatalytic cleavages as proposed earlier by Johansson et al. (J. Proteome Res. 2009 , 8 , 3549 - 3557).

Poly(adenylic acid) complementary DNA real-time polymerase chain reaction in pancreatic ductal juice in patients undergoing pancreaticoduodenectomy

OBJECTIVES

There is a need to develop methods of early diagnosis for pancreatic cancer. Pancreatic juice is easily collected by endoscopic retrograde cholangiopancreatography and may facilitate diagnosis using molecular markers. The aim of this work was to explore the feasibility of measurement of gene expression in RNA isolated from ductal juice.

METHODS

Intraoperative sampling of pancreatic juice was undertaken in 27 patients undergoing pancreaticoduodenectomy for suspected tumor. Total RNA was extracted and used as template for poly(adenylic acid) (poly[A]) polymerase chain reaction (PCR) to generate a globally amplified complementary DNA pool representative of all expressed messenger RNAs. Real-time PCR was performed for trefoil factor 2 (TFF2), carboxypeptidase B1 (CPB1), and kallikrein-related peptidase 3 (KLK3) in a subset of samples; all samples were normalized for 3 reference genes (glyceraldehyde-3-phosphate dehydrogenase [GAPDH], PSMB6, and beta-2-microglobulin [B2M]).

RESULTS

The median volume of the pancreatic juice obtained was 1245 microL (range, 50-5000 microL). The RNA integrity number ranged from 1.9 to 10. Reverse transcriptase PCR was positive for pancreas-specific genes (TFF2 and CPB1) and negative for prostatic-specific antigen in all samples.

CONCLUSIONS

These results demonstrate that RNA analysis of pancreatic juice is feasible using a combination of poly(A) PCR and real-time PCR. In addition, the poly(A) complementary DNA generated can be probed for multiple genes and is indefinitely renewable, thereby representing a molecular block of importance for future research.

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.

Trefoil factors in human milk

We measured concentrations of the gastrointestinal protective peptides Trefoil factors in human milk. By the use of in-house ELISA we detected high amounts of TFF3, less TFF1 and virtually no TFF2 in human breast milk obtained from 46 mothers with infants born extremely preterm (24-27 wk gestation), preterm (28-37 wk gestation), and full term (38-42 wk gestation). Samples were collected during the first, second, third to fourth weeks and more than 4 wks postpartum. Median (range) TFF1 [TFF3] concentrations in human milk were 320 (30-34000) [1500 (150-27,000)] pmol/L in wk 1, 120 (30-720) [310 (50-7100)] pmol/L in wk 2, 70 (20-670) [120 (20-650)] pmol/L in wks 3 to 4, and 60 (30-2500) [80 (20-540)] pmol/L in >4 wks after delivery. The lowest concentrations of TFF1 and TFF3 were found later than 2 wks after birth. In conclusion, TFF was present in term and preterm human milk with rapidly declining concentrations during the first weeks post partum. The clinical significance of TFF present in human milk remains to be explored, both regarding development of the fetal gut and protection against necrotizing enterocolitis.

Intestinal trefoil factor produced in Escherichia coli promotes the healing of rat burn-induced acute gastric mucosal lesions

BACKGROUND

Intestinal trefoil factor (ITF), a member of the trefoil factor family, plays an important role in protecting the epithelial layer of the gastrointestinal tract from damage and repairing epithelium after injury. This study aims to produce ITF by Escherichia coli expression system and explore its role in the treatment of burn-induced acute gastric mucosal lesions.

METHODS

Human ITF (hITF) gene encoding mature peptide was obtained by RT-PCR, and then inserted into the expression vector pET32a to construct the recombinant pET32a-hITF. After confirmation by gene sequencing, pET32a-hITF was transformed into E. coli Origami B(DE3), and TrxA-hITF fusion protein was expressed by conventional isopropyl-beta-d-thiogalactopyranoside induction in shake flask and analyzed with sodium dodecyl sulfate-polyacrylamide gel electorphoresis (SDS-PAGE) and Western-blot. Subsequently, TrxA-hITF was isolated by Nickel-nitrilotriacetic acid affinity chromatography, and ultrafiltration. Finally, a burn-induced rat gastric injury model was established, TrxA-hITF was administered orally and macroscopic and microscopic changes in gastric mucosa were observed.

RESULTS

The correctness and integrity of hITF gene were identified by restriction digestion and gene sequencing. TrxA-hITF fusion protein was successfully expressed to 50 mg/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 32 kDa, a little larger than the calculated value, 30 kDa. Lesion score and histologic examination revealed that TrxA-hITF alleviated rat gastric injury significantly.

CONCLUSIONS

This study lays foundation for the commercial production of hITF and suggests a new way to treat burn-induced gastric lesions.

Advances in research of trefoil factor 3

As one of important defensive factors, trefoil factor 3 (TFF3) has considerable relation to the lesion, recovery, proliferation and malignancy of gastrointestinal mucosa. Furthermore, the correlation between TFF3 and tumor, including its pathogenesis, progress and prognosis, has been reported remarkably. However, the binding proteins of TFF3 remains to be confirmed and the research of TFF3 on the mechanism of action and signal transduction pathway is just initial. This article reviewed the progress in TFF3 research.

Salivary trefoil factor 3 enhances migration of oral keratinocytes

Trefoil factor 3 (TFF3) is a member of the mammalian TFF family. Trefoil factors are secreted onto mucosal surfaces of the entire body and exert different effects according to tissue location. Trefoil factors may enhance mucosal healing by modulating motogenic activity, inhibiting apoptosis, and promoting angiogenesis. Trefoil factor 3 is secreted from the submandibular gland and is present in whole saliva. The aim of this study was to assess the migratory and proliferative effects of TFF3 on primary oral human keratinocytes and oral cancer cell lines. The addition of TFF3 increased the migration of both normal oral keratinocytes and the cancer cell line D12, as evaluated by a two-dimensional scratch assay. By contrast, no increase in proliferation or energy metabolism was observed after stimulation with TFF3. Trefoil factor 3-enhanced migration was found to be driven partly by the extracellular signal-related kinase (Erk1/2) pathway, as shown by addition of the mitogen-activated protein kinase (MAPK) inhibitor PD 98059. Previous functional studies on trefoil peptides have all been based on cells from monolayered epithelium like the intestinal mucosa; this is the first report to show that normal and cancerous keratinocytes from stratified epithelium respond to TFF stimuli. Taken together, salivary TFF3 is likely to contribute to oral wound healing.

TFF3 and EGF induce different migration patterns of intestinal epithelial cells in vitro and trigger increased internalization of E-cadherin

BACKGROUND/AIMS

TFF3, a member of the TFF (trefoil factor family) peptides, and epidermal growth factor (EGF) actively support the repair of mucosal barriers, particularly during restitution. The aim of this study was to compare the motogenic effects of TFF3 and EGF.

METHODS

The influence of recombinant human TFF3 (dimeric form) and EGF on the migration of IEC-18 cells was characterized in an in vitro restitution model (scratch wound assay) with the help of time-lapse video microscopy, morphometry, and immunocytochemistry including confocal laser scanning microscopy.

RESULTS

TFF3- and EGF-treated cells re-populated the wounded area via different migration patterns; TFF3 treatment resulted in the formation of continuous sheets of migrating cells with only a few gaps. In contrast, EGF-treated cells formed a network of migrating cells (often with a fibroblast-like morphology) with numerous gaps and only punctual contacts. TFF3 and EGF treatment also changed the localization of E-cadherin indicating endocytotic recycling and/or degradation of E-cadherin.

CONCLUSION

TFF3, in contrast to EGF, enhanced a collective cell migration ensuring a precise coverage of the re-populated area avoiding gaps.

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.

Pharmacokinetics of trefoil peptides and their stability in gastrointestinal contents

Trefoil factor family (TFF) peptides are considered promising for therapeutic use in gastrointestinal diseases, and there is a need to explore the fate of injected TFF and the stability of the peptides in the gastrointestinal tract. We studied the pharmacokinetics of intravenously (i.v.) administered hTFF2 in mice and rats and of hTFF3 administered i.v., intramuscularly, intraperitoneally, and subcutaneously in mice, and estimated by ELISA the decay of the peptides added to rat and human gastrointestinal contents. We found that i.v. injected hTFF2 and hTFF3 were cleared from the circulation within 2-3h, exhibiting comparable pharmacokinetic profiles. In contents from the rat stomach, hTFF levels remained unchanged for up to 6 days. In the small and large intestine of rats, the hTFF levels decreased markedly after 4 and 1h, respectively. In small intestinal contents from humans, the levels remained stable for more than 24h. We conclude that systemically administered hTFF2 and hTFF3 are rapidly eliminated from the circulation and that the stability of hTFF2 and hTFF3 in GI contents appeared higher in the gastric and small intestinal milieu than in the large intestine and feces, suggesting a higher stability toward gastric acid and digestive enzymes than toward microbial degradation.

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.

Tissue localization of human trefoil factors 1, 2, and 3

Trefoil factors (TTFs) are small, compact proteins coexpressed with mucins in the gastrointestinal tract. Three trefoil factors are known in mammals: TFF1, TFF2, and TFF3. They are implicated to play diverse roles in maintenance and repair of the gastrointestinal channel. We compared the expression pattern of the three trefoil factors analyzing mRNA from a panel of 20 human tissues by conventional reverse transcriptase (RT) PCR and, in addition, by real-time PCR. These findings were supported by immunohistochemical analysis of paraffin-embedded human tissues using rabbit polyclonal antibodies raised against these factors. TFF1 showed highest expression in the stomach and colon, whereas TFF2 and TFF3 showed highest expression in stomach and colon, respectively. All three TFFs were found in the ducts of pancreas. Whereas TFF2 was found to be restricted to these two tissues, the structurally more closely related TFF1 and TFF3 showed a more general tissue distribution and were found to colocalize on an array of mucosal surfaces. This is the first thorough parallel description of the tissue distribution of TFFs in normal tissues, and it provides a baseline for similar analysis in diseased tissues.

Systemically administered trefoil factors are secreted into the gastric lumen and increase the viscosity of gastric contents

BACKGROUND AND PURPOSE

Trefoil factors (TFFs) secreted by mucus-producing cells are essential for the defence of the gastrointestinal mucosa. TFFs probably influence the viscoelastic properties of mucus, but this has not been demonstrated in vivo. We therefore studied the gastric secretion of systemically administered TFF2 and TFF3, and their influence on the viscosity of the secretions.

EXPERIMENTAL APPROACH

Mice and rats under general anaesthesia were injected intravenously with human (h) TFF2, hTFF3 (5 mg kg(-1) to mice and 25 mg kg(-1) to rats), murine (m) (125)I-TFF3, or (125)I-hTFF3 (300,000 cpm, mice only). The appearance of TFFs in the gastric mucosa and luminal secretions was analysed by autoradiography, gamma-counting, and ELISA, and the viscosity by rheometry.

KEY RESULTS

(125)I-mTFF3 and (125)I-hTFF3 were taken up by secretory cells of the gastrointestinal tract and detected at the gastric mucosal surface 15 min after injection. Stressing the stomach by carbachol (3.5 microg kg(-1)) and pyloric ligation significantly increased the uptake. Injected hTFF2, hTFF3, and mTFF3 were retrieved from the gastric contents after 4 h. In rats, an approximately seven-fold increase in the viscosity was detected after injection of TFF2 compared to the controls, whereas TFF3 did not increase the viscosity. In mice, TFF2 increased the viscosity approximately 4-fold.

CONCLUSIONS

These data indicate that systemically administered TFFs are transferred to the gastric lumen in a biologically active form.

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High-level expression of human TFF3 in Escherichia coli

A strategy for expression and purification of recombinant N-terminal human trefoil factor family-domain peptide 3 (hTFF3) in Escherichia coli was established. The gene of hTFF3 was synthesized to substitute the low-usage condons with corresponding high-usage synonymous condons. At the same time, the signal peptide of DsbC was added to the N-terminus of the hTFF3 gene. The mature recombinant hTFF3 was located in the periplasm of E. coli, which can be released by sonication. The protein was further purified by a two-step cation exchange chromatography mentod. The yield is about 14-15 mg/l of culture. The biological activity of purified hTFF3 was analyzed by cell-based apoptosis assay, which shows that the recombinant hTFF3 is biologically active.

Luminal and parenteral TFF2 and TFF3 dimer and monomer in two models of experimental colitis in the rat

BACKGROUND

Peptides of the trefoil factor family (TFF1, TFF2 and TFF3) are cosecreted with mucus from mucus-producing cells in most organ systems and are believed to interact with mucus to form high-viscosity stable gel complexes. In the gastrointestinal tract, they sustain the mucosal barrier, and both injected and orally administered TFF peptide have protective and healing functions in the gastric mucosa.

AIM

To investigate the possible treatment effect of luminally and parenterally administered TFF peptides in experimental colitis in rats.

METHODS

Colitis was induced by administration of 5% dextran sodium sulphate in the drinking water or by one intraperitoneal injection of mitomycin C, 3.75 mg/kg. TFF peptides were administered as subcutaneous injections or directly into the lumen via a catheter placed in the proximal colon. Treatments were saline, TFF2, TFF3 monomer or TFF3 dimer 5 mg/kg twice per day throughout the study [dextran sulphate sodium (DSS)] or from day 4 to 7 (mitomycin C). Colitis severity was scored in a stereomicroscope and histologically.

RESULTS

Luminal treatment with TFF3 in its dimeric form significantly improved the colitis score in both colitis models, whereas TFF2 had positive effect only in DSS-induced colitis. The TFF3 monomer was without any effects in both models. Treatment effect was most pronounced in the middle part of the colon, closest to the tip of the catheter. Injected TFF peptides, especially the TFF3 monomer, aggravated the colitis score in both colitis models.

CONCLUSIONS

Intracolonic administration of TFF3 dimer and TFF2 improves experimentally induced colitis in rats. The TFF3 monomer has no effect. Parenteral administration of TFF peptides aggravates the colitis especially the TFF3 monomer.

Trial of trefoil factor 3 enemas, in combination with oral 5-aminosalicylic acid, for the treatment of mild-to-moderate left-sided ulcerative colitis

BACKGROUND

Current treatment of ulcerative colitis is imperfect. Trefoil peptides are known to stimulate repair in many models of injury, including animal models of colitis.

AIM

To assess the efficacy of trefoil factor family-3 enema treatment in a clinical trial.

METHODS

A total of 16 patients with mild-to-moderate left sided ulcerative colitis were recruited into a double-blind randomized placebo-controlled study. Patients taking steroids or with proctitis only were excluded. Patients received 75 mL enemas containing either human recombinant trefoil factor family-3 (10 mg/mL) or saline alone once a day for 14 days. All patients also received an oral dose-increment of 1.2 g of mesalazine daily above their normal usage. Patients were assessed at 0, 2, 4 and 12 weeks. Remission was defined as Ulcerative Colitis Disease Activity Index of 0 or 1 with no blood in stool. Individual clinical improvement was defined as a Ulcerative Colitis Disease Activity Index reduction of >3. Data was analysed using chi-square test and anova.

RESULTS

Median Ulcerative Colitis Disease Activity Index at entry were 8.5 (trefoil factor family-3 group) and 8 (placebo group). Analysed on an intention-to-treat basis, only one patient went into remission (in trefoil factor family-3 group at day 28). Clinical improvement was seen in two trefoil factor family-3 and three placebo patients on day 14 and two patients in each group on day 28.

CONCLUSION

Increasing the dose of 5-aminosalicylic acid was moderately effective in reducing the Ulcerative Colitis Disease Activity Index but was insufficient to induce remission. Trefoil factor family-3 enemas were well-tolerated but did not provide additional benefit above that of adding additional 5-aminosalicylic acid alone.

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.

Epidermal growth factor and trefoil factor family 2 synergistically trigger chemotaxis on BEAS-2B cells via different signaling cascades

Injured areas of the respiratory epithelium are subject to rapid repair by the migration of adjacent epithelial cells, a process termed "restitution". Rapid re-epithelialization is promoted by interactions between migrating cells and the extracellular matrix proteins. Furthermore, epidermal growth factor (EGF) as well as trefoil factor family (TFF) peptides are well known regulators of epithelial restitution due to their motogenic effects. Migration of the human bronchial epithelial cell line BEAS-2B in modified Boyden chambers was used as a model system for airway restitution. EGF or recombinant human TFF2 or TFF3 showed mainly chemotactic activity. The motogenic response was strictly dependent upon a haptotactic substrate, but to different degrees. EGF induced phosphorylation of extracellular signal-regulated kinases (ERK) 1/2, c-Jun-N-terminal kinase, p38, Akt, and p70S6K in BEAS-2B cells. Using specific inhibitors, the signaling cascades responsible for the motogenic response were shown to differ drastically when EGF was compared with TFF2. The motogenic effect of TFF2 was previously demonstrated to depend on ERK1/2 and protein kinase C activation; whereas the EGF-triggered motogenic response was completely independent of ERK1/2 activation but sensitive to the inhibition of phosphoinositide 3-kinase, p38, protein kinase C, or nuclear factor kappaB. However, the motogenic effects of EGF and TFF2 are additive. These data suggest that luminal EGF and TFF peptides can act synergistically in the human respiratory epithelium to enhance rapid repair processes in the course of diseases such as asthma.

Bacterial expression and purification of biologically active human TFF3

A glutathione S-transferase (GST) fusion protein expression system for the production and purification of recombinant human trefoil factor family-domain peptide 3 (hTFF3) was established. The hTFF3 gene, prepared by PCR, was cloned into a pBluescript KS(+) plasmid, and inserted into a pGEX-4T-1 GST fusion vector. The GST-hTFF3 fusion protein was expressed in Escherichia coli, and hTFF3 was purified with Glutathione Sepharose 4B affinity chromatography, yielding about 3-4 mg of pure hTFF3 in one liter of culture broth. The biological activity of purified hTFF3 was tested in two previously reported rat gastric ulcer models. Oral administration of recombinant hTFF3 has a dose dependent protective effect against ethanol-induced or pylorus ligation-induced gastric mucosa injury in rat, which indicates that our recombinant hTFF3 is biologically active.

Characterization of a CCAAT-enhancer element of trefoil factor family 2 (TFF2) promoter in MCF-7 cells

Trefoil factors family 2 (TFF2), also known as spasmolytic polypeptide, is primarily expressed in the mucus neck cells of gastrointestinal tracts. It has been proposed that TFF2 plays an important physiological role in protection, repair, and healing of gastrointestinal mucosa. To investigate the cis-acting regulatory element that control TFF2 tissue-specific expression, we studied the basal TFF2 promoter activity through transient transfection in several human cancer cell lines. Expression of TFF2 was found to be significantly greater in human breast cancer MCF-7 cells compared to other cancer cells. Results from TFF2 promoter luciferase reporter constructs revealed that the basal level of TFF2 promoter activity was overall more than two-fold higher in MCF-7 cells compared to that of other cell lines examined. Using EMSA assays and site-directed mutagenesis, we identified a cell line-specific transcriptional regulation element located in the TFF2 promoter 5'-flank sequence at -32/-27, and which contains a CCAAT/enhance binding proteins (C/EBPs) consensus-binding site. Mutation of this consensus site reduced the basal promoter activity by more than 50% in MCF-7 cells but had no effect in human gastric cancer cells. In conclusion, we have identified a CCAAT sequence as a cell line-specific cis-acting regulatory element that may contribute to the high level expression of TFF2 in MCF-7 cells. These results also suggest the possibility that TFF2 could play a role in mammary gland tumorigenesis.

Extraction and purification of biologically active intestinal trefoil factor from human meconium

Intestinal trefoil factor (TFF3/ITF), a member of trefoil factor family (TFF) domain peptides, is normally expressed by goblet cells and secreted into the lumen of the intestinal tract, and plays an important role in the maintenance and repair of the intestinal mucosal barrier. Significant amounts of TFF3/ITF are present in the meconium of human infants. Here, we describe a relatively simple method for extraction and purification of natural human TFF3/ITF from meconium. The purification methods include acid treatment, ammonium sulfate precipitation, isoelectric precipitation, and iron exchange chromatography. A relatively large amount of natural TFF3/ITF can be purified from meconium of full-term infants and this purified, natural TFF3/ITF is biologically active in an ethanol-induced rat gastric mucosal injury model.

Injected TFF1 and TFF3 bind to TFF2-immunoreactive cells in the gastrointestinal tract in rats

Peptides of the trefoil factor family (TFF1, TFF2 and TFF3) are co-secreted with mucus in most organ systems and are believed to interact with mucins to produce high-viscosity, stable gel complexes. We have previously demonstrated that cells in the GI tract possess binding sites to TFF2 and that injected TFF2 ends up in the mucus layer. In the present study, tissue binding and metabolism of parenterally administered human TFF1 and TFF3 in rats were described and compared to the immunohistochemical localization of the TFF peptides. 125I-TFF1 monomer and 125I-TFF3 mono- and dimer were given intravenously to female Wistar rats. The tissue distribution was assessed by gamma counting of organ samples and by autoradiography of histological sections. The degradation of 125I-TFF3 was studied by means of trichloracetic acid (TCA) precipitation and the saturability of the binding by administration of excess unlabelled peptide. The TFF peptides were localized in histologic sections from the GI tract by immunohistochemistry. Injected TFF3 dimer (12%) was taken up by the GI tract. At autoradiography, grains were localized to the same cells that were immunoreactive to TFF2. The binding could be displaced by excess TFF3. Similar binding was observed for the TFF1 and TFF3 monomers apart from binding in the stomach, where the uptake was only 15% in comparison to the dimer. There was no specific binding outside the GI tract and no binding to TFF1 or TFF3 immunoreactive cells. In conclusion, the TFF2-binding cells in the gastrointestinal tract seem to have basolateral, receptor-like activity to all three TFF peptides. The mucous neck cells of the stomach predominantly take up TFFs with two trefoil domains, indicating a different receptor-like activity in the stomach compared to the rest of the GI tract.

Selective abrogation of the proinvasive activity of the trefoil peptides pS2 and spasmolytic polypeptide by disruption of the EGF receptor signaling pathways in kidney and colonic cancer cells

Trefoil peptides (TFFs) are now considered as scatter factors, proinvasive and angiogenic agents acting through cyclooxygenase-2 (COX-2)- and thromboxane A2 receptor (TXA2-R)-dependent signaling pathways. As expression and activation levels of the epidermal growth factor receptor (EGFR) predict the metastatic potential of human colorectal cancers, the purpose of this study was to establish whether the EGF receptor tyrosine kinase (EGFR-TK) contributes to cellular invasion induced by TFFs in kidney and colonic cancer cells. Both the dominant negative form of the EGFR (HER-CD533) and the EGFR-TK inhibitor ZD1839 (Iressa) abrogated cellular invasion induced by pS2, spasmolytic polypeptide (SP) and the src oncogene, but not by ITF and the TXA2-R. Similarly, EGFR-TK inhibition by ZD1839 reversed the invasive phenotype promoted by the constitutively activated form of the EGFR (EGFRvIII) and the EGFR agonists transforming growth factor alpha (TGFalpha), amphiregulin and EGF. We also provide evidence that TFFs, EGFRvIII, and TGFalpha trigger common proinvasive pathways using the PI3'-kinase and Rho/Rho- kinase cascades. These findings identify the EGFR-TK as a key signaling element for pS2- and SP-mediated cellular invasion. It is concluded that although pS2, SP and ITF belong to the same family of inflammation- and cancer-associated regulatory peptides, they do not control identical signaling networks.

Ontogeny and prenatal expression of trefoil factor 3/ITF in the human intestine

BACKGROUND

Trefoil factor 3 (TFF3) or intestinal trefoil factor (ITF), a peptide normally expressed and secreted by goblet cells at the mucosal surface of the small intestine and colon, is important for the maintenance and repair of the intestinal mucosal barrier.

AIM

To study the ontogeny and developmental expression of TFF3 in human intestine.

SUBJECTS

We examined TFF3 expression in formalin-fixed and paraffin-embedded intestinal tissues from 24 fetuses (gestational age [GA] 12-23 weeks) and 5 adults by immunohistochemical staining. To determine whether TFF3 is excreted into the fetal intestinal tract, first-passed meconium samples were collected from 43 newborn infants (gestational age 24-41 weeks). The presence of TFF3 was examined by Western blot analysis and the relative levels of TFF3 in the meconium were quantified with a slot blot assay.

RESULTS

TFF3 can be detected by immunohistochemistry in human intestine as early as 12 weeks gestation. TFF3 is present in the meconium of newborn infants; no significant difference exists in TFF3 levels in the meconium of premature infants with birth weight (BW) less than 1500 g compared to those with birth weight equal to or more than 1500 g.

CONCLUSION

Premature infant's susceptibility to intestinal mucosal injury is unlikely to be explained by developmental expression of TFF3 in human intestine since secreted TFF3 is not deficient in premature infants.

Clinical, cellular, and molecular aspects of cancer invasion

Invasion causes cancer malignancy. We review recent data about cellular and molecular mechanisms of invasion, focusing on cross-talk between the invaders and the host. Cancer disturbs these cellular activities that maintain multicellular organisms, namely, growth, differentiation, apoptosis, and tissue integrity. Multiple alterations in the genome of cancer cells underlie tumor development. These genetic alterations occur in varying orders; many of them concomitantly influence invasion as well as the other cancer-related cellular activities. Examples discussed are genes encoding elements of the cadherin/catenin complex, the nonreceptor tyrosine kinase Src, the receptor tyrosine kinases c-Met and FGFR, the small GTPase Ras, and the dual phosphatase PTEN. In microorganisms, invasion genes belong to the class of virulence genes. There are numerous clinical and experimental observations showing that invasion results from the cross-talk between cancer cells and host cells, comprising myofibroblasts, endothelial cells, and leukocytes, all of which are themselves invasive. In bone metastases, host osteoclasts serve as targets for therapy. The molecular analysis of invasion-associated cellular activities, namely, homotypic and heterotypic cell-cell adhesion, cell-matrix interactions and ectopic survival, migration, and proteolysis, reveal branching signal transduction pathways with extensive networks between individual pathways. Cellular responses to invasion-stimulatory molecules such as scatter factor, chemokines, leptin, trefoil factors, and bile acids or inhibitory factors such as platelet activating factor and thrombin depend on activation of trimeric G proteins, phosphoinositide 3-kinase, and the Rac and Rho family of small GTPases. The role of proteolysis in invasion is not limited to breakdown of extracellular matrix but also causes cleavage of proinvasive fragments from cell surface glycoproteins.

Trefoil peptides as proangiogenic factors in vivo and in vitro: implication of cyclooxygenase-2 and EGF receptor signaling

We previously established that the trefoil peptides (TFFs) pS2, spasmolytic polypeptide, and intestinal trefoil factor are involved in cellular scattering and invasion in kidney and colonic cancer cells. Using the chorioallantoic membrane (CAM) assay and the formation of tube-like structures by human umbilical vein endothelial cells (HUVEC) plated on the Matrigel matrix substratum, we report here that TFFs are proangiogenic factors. Angiogenic activity of TFFs is comparable to that induced by vascular endothelial growth factor, leptin, and transforming growth factor-alpha. Stimulation of angiogenesis by pS2 in the CAM assay is blocked by pharmacological inhibitors of cyclooxygenase COX-2 (NS-398) and epidermal growth factor receptor (EGF-R) tyrosine kinase (ZD1839), but is independent of KDR/Flk-1 and thromboxane A2 receptors. In contrast, the morphogenic switch induced by pS2 in HUVEC cells could be inhibited by the specific KDR heptapeptide antagonist ATWLPPR and by inhibitors of COX-2 and EGF-R signaling. These results implicate TFFs in the formation of new blood vessels during normal and pathophysiological processes linked to wound healing, inflammation, and cancer progression in the digestive mucosa and other human solid tumors associated with aberrant expression of TFFs.