A novel 25 bp tandem repeat within the human trefoil peptide gene TFF2 in 21q22.3: polymorphism and mammalian evolution

Inflammatory signals that regulate intestinal epithelial renewal, differentiation, migration and cell death: Implications for necrotizing enterocolitis

Necrotizing enterocolitis is a disease entity with multiple proposed pathways of pathogenesis. Various combinations of these risk factors, perhaps based on genetic predisposition, possibly lead to the mucosal and epithelial injury that is the hallmark of NEC. Intestinal epithelial integrity is controlled by a tightly regulated balance between proliferation and differentiation of epithelium from intestinal epithelial stem cells and cellular loss by apoptosis. various signaling pathways play a key role in creating and maintaining this balance. The aim of this review article is to outline intestinal epithelial barrier development and structure and the impact of these inflammatory signaling and regulatory pathways as they pertain to the pathogenesis of NEC.

Promoter polymorphisms in trefoil factor 2 and trefoil factor 3 genes and susceptibility to gastric cancer and atrophic gastritis among Chinese population

The polymorphisms in trefoil factor (TFF) gene family that protect gastrointestinal epithelium might influence individual vulnerability to gastric cancer (GC) and atrophic gastritis. We used the Sequenom MassARRAY platform to identify the genotypes of TFF2 rs3814896 and TFF3 rs9981660 polymorphisms in 478 GC patients, 652 atrophic gastritis patients, and 724 controls. For the TFF2 rs3814896 polymorphism, in the subgroup aged ≤ 50 years, we found that AG+GG genotypes were associated with a 0.746-fold decreased risk of atrophic gastritis [p=0.023, 95% confidence interval (CI)=0.580-0.960], a 0.626-fold decreased risk of GC (p=0.005, 95% CI=0.451-0.868), and a 0.663-fold decreased risk of diffuse-type GC (p=0.034, 95% CI=0.452-0.970) compared with the common AA genotype. For the TFF3 rs9981660 polymorphism, in the male subgroup, individuals with variant AG+AA genotype were associated with a 0.761-fold decreased risk of diffuse-type GC compared with the common GG genotype (p=0.043, 95% CI=0.584-0.992). Additionally, we found that in subjects aged ≤ 50 years compared with common AA genotype, TFF2 rs3814896 AG+GG genotypes were associated with increased TFF2 mRNA levels in the total gastric cancer specimens and in the diffuse-type gastric cancer specimens; and in males aged ≤ 50 years compared with common GG genotype, TFF3 rs9981660 AA+AG genotypes were associated with TFF3 mRNA levels in diffuse-type gastric cancer tissues and their corresponding non-cancerous tissues. To our knowledge, this is the first report of an association between the TFF2 rs3814896 AG+GG genotypes and decreased risks of GC, diffuse-type GC, and atrophic gastritis in younger people aged ≤ 50 years, and an association between TFF3 rs9981660 AG+AA genotype and decreased risk of diffuse-type GC in men. Moreover, we found that TFF2 rs3814896 AG+GG genotypes in people aged ≤ 50 years and TFF3 rs9981660 AG+AA genotypes in younger males with diffuse-type GC were associated with higher levels of TFF2 and TFF3 mRNA respectively.

Trefoil factor family (TFF) peptides and cancer progression

TFF peptides are involved in mucosal maintenance and repair through motogenic and antiapoptotic activities. These peptides are overexpressed during inflammatory processes and cancer progression. They also function as scatter factors, proinvasive and angiogenic agents. Such a divergence is related to the pathophysiological state of tissues submitted to persistent aggressive situations during digestive processes in the normal gastrointestinal tract, inflammatory and neoplastic diseases. In agreement with this model, TFF peptides are connected with multiple oncogenic pathways. As a consequence, the TFF signaling pathways may serve as potential targets in the control of chronic inflammation and progression of human solid tumors.

Trefoil factors: initiators of mucosal healing

Maintaining the integrity of the gastrointestinal tract, despite the continual presence of microbial flora and injurious agents, is essential. Epithelial continuity depends on a family of small, yet abundant, secreted proteins--the trefoil factors (TFFs). TFFs protect mucous epithelia from a range of insults and contribute to mucosal repair, although the signalling events that mediate these responses are only partially understood.

Association of pS2 (TFF1) release with breast tumour proliferative rate: in vitro and in vivo studies

Although cytosolic expression of the protein pS2 (TFF1) is considered to be a marker of oestrogen receptor (OR) function, there exists some clinical data to suggest an inverse relationship of cytosolic pS2 to tumour proliferation. Although secreted from breast cancer cells, the relationship of pS2 secretion to tumour natural history has been little studied. The mechanisms and kinetics of pS2 release and its relation to tumour cell proliferation were studied in a human breast cancer cell line MCF-7 and verified in a preliminary clinical study. Stimulation by stripped serum or oestradiol resulted in parallel increases of proliferation and pS2 release in both time course and dose-response experiments. Direct pharmacological alterations of proliferation were followed by identical changes in pS2 release. The relationship between serum pS2 levels and tumour proliferative activity when analysed as a function of steroid status showed a slope of 0.56 in OR+ vs. 0.19 in OR- tumours. It is concluded that pS2 release from breast cancer cells is associated with their proliferation and measurement of serum pS2 levels might be a good predictor of tumour proliferative state and could permit noninvasive monitoring of this tumour parameter.

Cell type specific expression of secretory TFF peptides: colocalization with mucins and synthesis in the brain

The "TFF domain" is an ancient cysteine-rich shuffled module forming the basic unit for the family of secretory TFF peptides (formerly P-domain peptides and trefoil factors). It is also an integral component of mosaic proteins associated with mucous surfaces. Three mammalian TFF peptides are known (i.e., TFF1-TFF3); however, in Xenopus laevis the pattern is more complex (xP1, xP4.1, xP4.2, and xP2). TFF peptides are typical secretory products of a variety of mucin-producing epithelial cells (e.g., the conjunctiva, the salivary glands, the gastrointestinal tract, the respiratory tract, and the uterus). Each TFF peptide shows an unique expression pattern and different mucin-producing cells are characterized by their specific TFF peptide/secretory mucin combinations. TFF peptides have a pivotal role in maintaining the surface integrity of mucous epithelia in vivo. They are typical constituents of mucus gels, they modulate rapid mucosal repair ("restitution") by their motogenic and their cell scattering activity, they have antiapoptotic effects, and they probably modulate inflammatory processes. Pathological expression of TFF peptides occurs as a result of chronic inflammatory diseases or certain tumors. TFF peptides are also found in the central nervous system, at least in mammals. In particular, TFF3 is synthesized from oxytocinergic neurons of the hypothalamus and is released from the posterior pituitary into the bloodstream.

Mouse Trefoil factor genes: genomic organization, sequences and methylation analyses

The mammalian Trefoil Factors (TFFs), TFF1/pS2, TFF2/SP and TFF3/ITF, are expressed and secreted throughout the gastrointestinal tract with a specific and complementary pattern. These proteins exhibit common functions in the protection and repair process of the gastrointestinal epithelial barrier. Here, we report the clustered organization of the three mouse TFF genes in a 40 kb DNA segment, in a head to tail orientation in the following order: TFF1, TFF2, and TFF3. Computer comparison of the mouse TFF promoter sequences to their human counterparts revealed conserved boxes in both mouse and human genes. Promoter methylation analyses showed that, in tissues where these genes are normally expressed, the proximal promoters of TFF1 and TFF2 are specifically not methylated and that of TFF3 is partially demethylated. In contrast, in organs that do not express TFFs, the promoters of the three genes are methylated. These findings strongly argue for the involvement of epigenetic mechanisms in the regulation of TFF expression in normal and pathological conditions.

Tracing the evolutionary origin of the TFF-domain, an ancient motif at mucous surfaces

Mammalian trefoil factor family (TFF)-domain peptides promote gastrointestinal protection, healing and cell migration and may act as tumour suppressors. TFF-like domains also constitute modules of composite proteins like mucin glycoproteins and zona pellucida proteins. Database searches with a modified, less stringent consensus sequence - C-x(5,6)-[ST]-x(3)-C-x(4,5)-C-C-[FYWH]-x(2, 24)-C-[FY] - revealed that ancestors of the TFF-domain arose before amphibian evolution. Eggshell proteins and a zona pellucida-like protein in teleost species, an epidermis-specific protein in a tunicate as well as an open reading frame in a nematode exhibited TFF-like motifs suggesting that they most likely originated in some multicellular organism.