Obstructive sleep apnea (OSA) is one of the most common chronic diseases. Trefoil factor family 3 (TFF3) peptides are secreted by major and minor salivary glands and may be involved in the pathogenesis of OSA. This study aimed to evaluate salivary TFF3 and flow rate between those with and without OSA.
This was a prospective experimental study that enrolled patients with OSA and non-OSA. Total unstimulated saliva was collected, the salivary flow rate was measured, and the TFF3 level was analyzed by using a modified sandwich enzyme-linked immunosorbent assay. Baseline characteristics, TFF3 level, and salivary flow rate were compared between both groups. Factors associated with the TFF3 level and flow rate were computed by using multivariate linear regression analysis.
Twenty-eight participants were recruited in the study: 20 patients with OSA (71.42%) and 8 non-OSA as control. The TFF3 and salivary flow rates between both groups of non-OSA versus OSA were comparable (TFF3 non-OSA 61.06 vs. OSA 96.00 ng/mg; p = .276 and flow rate non-OSA 0.40 vs. OSA 0.35 mL/min; p = .320). Factors associated with the TFF3 level were neck circumference with a negative coefficient of -16.419 (p =  .042). For the salivary flow rate, only age was a significant factor with the coefficient of -0.013 (p = .044).
TFF3 and salivary flow rate were comparable between patients with OSA and non-OSA. The factor associated with TFF3 level was neck circumference, while age was negatively associated with the salivary flow rate in patients with OSA.

OBJECTIVE: To explore the molecular mechanisms of Weifuchun in the treatment of gastric intestinal metaplasia (GIM), we designed a preclinical pilot study to examine potential markers of disease progression based on alterations in the tongue flora.
METHODS: Total 27 patients with GIM were treated with Weifuchun for 4 weeks and 26 volunteers as controls. Tongue coating bacteria were profiled using 16S rDNA high-throughput sequencing. Serum pepsinogen I and II levels were detected using the latex immunoturbidimetric assay. The levels of serum trefoil factor I was detected by ELISA. Microplate-based quantification was used to detect serum total bile acid (TBA).
RESULTS: After treatment, the relative abundance of 4 dominant tongue coating genera (Granulicatella, Gemella, Lachnoanaerobaculum, and Neisseria) increased significantly wheras Alloprevotella, [Eubacterium] nodatum group, Prevotell, and Ruminococcaceae UCG-014 decreased (P < .05). The results showed that Alloprevotella and 3 rare tongue coating genera (Lautropia, Treponema 2, and Aliihoeflea) might be potential markers or target flora for the treatment of GIM. Kyoto encyclopedia of genes and genomes (KEGG) function prediction analysis showed that Weifuchun may regulate bile secretion and folate biosynthesis in patients with GIM. The level of serum trefoil factor I decreased significantly in response to Weifuchun treatment, which was consistent with the decrease in folate biosynthesis predicted by KEGG.
CONCLUSIONS: Weifuchun may restore the balance of tongue flora by decreasing the levels of serum trefoil factor I, thereby providing a new way to measuring the underlying effectiveness and potential mechanisms of action of this traditional Chinese medicinal compound in the treatment of GIM.

During animal fasting, the nutrient supply and metabolism switch from carbohydrates to a new reliance on the catabolism of energy-dense lipid stores. Assembled under tight regulation, βγ-CAT (a complex of non-lens βγ-crystallin and trefoil factor) is a pore-forming protein and trefoil factor complex identified in toad Bombina maxima. Here, we determined that this protein complex is a constitutive component in toad blood, that actively responds to the animal fasting. The protein complex was able to promote cellular albumin and albumin-bound fatty acid (FA) uptake in a variety of epithelial and endothelial cells, and the effects were attenuated by a macropinocytosis inhibitor. Endothelial cell-derived exosomes containing largely enriched albumin and FAs, called nutrisomes, were released in the presence of βγ-CAT. These specific nutrient vesicles were readily taken up by starved myoblast cells to support their survival. The results uncovered that pore-forming protein βγ-CAT is a fasting responsive element able to drive cell vesicular import and export of macromolecular nutrients.

Peptic ulcer disease (PUD) is a common disease and frequently encountered in the clinic. Accumulating evidence suggests that PUD is associated with the gastrointestinal microbiota. Electroacupuncture (EA) is an improved version of acupuncture, which can improve the clinical effect by increasing the stimulation and delivering appropriate electrical pulses to needles. This method has been widely used in the treatment of peptic ulcer disease. However, its effect on gastrointestinal microbiota remains unclear. Therefore, in the present study, the ameliorative effect of EA was evaluated on the gastroduodenal mucosa, and the regulatory effect of the gastroduodenal microbiota was assessed in PUD mice. A total of 48 male Kun Ming mice were randomly divided into the following groups: normal control group (NC), PUD model group (PUD), Shousanli group (LI10), and Zusanli group (ST36) (n=12). The mice in groups LI10 and ST36 were treated with EA at LI10 and ST36, respectively. This intervention was continued for 7 days. Subsequently, we evaluated the morphological changes in the gastric and duodenal mucosa, and specific indices were measured, including the contents of serum dopamine (DA), the trefoil factor (TFF), and the vasoactive intestinal peptide (VIP). In addition, the gastric and duodenal microbiota were assessed via 16S ribosomal DNA sequencing. The results indicated that EA at LI10 or ST36 significantly reduced the injury of the gastroduodenal mucosa in PUD mice. The gastric microbial community structure of the groups LI10 and ST36 was similar to that of the NC group following comparison with the microbial community structure of the PUD model group. Moreover, the abundance of Firmicutes in the stomach was decreased, whereas that of Bacteroidetes was increased, and the abundance of Firmicutes in the duodenum was decreased. Furthermore, the microbial diversity and richness of the gastric microbiota in group LI10 were also significantly increased, and the serum dopamine and trefoil factor levels in group ST36 were significantly increased. Therefore, it is suggested that EA ameliorating PUD is in association with improving the levels of DA and TFF and regulating the relative abundances of Firmicutes and Bacteroidetes in the gastric microbiota.

As sequence and structure comparison algorithms gain sensitivity, the intrinsic interconnectedness of the protein universe has become increasingly apparent. Despite this general trend, β-trefoils have emerged as an uncommon counterexample: They are an isolated protein lineage for which few, if any, sequence or structure associations to other lineages have been identified. If β-trefoils are, in fact, remote islands in sequence-structure space, it implies that the oligomerizing peptide that founded the β-trefoil lineage itself arose de novo. To better understand β-trefoil evolution, and to probe the limits of fragment sharing across the protein universe, we identified both \'β-trefoil bridging themes\' (evolutionarily-related sequence segments) and \'β-trefoil-like motifs\' (structure motifs with a hallmark feature of the β-trefoil architecture) in multiple, ostensibly unrelated, protein lineages. The success of the present approach stems, in part, from considering β-trefoil sequence segments or structure motifs rather than the β-trefoil architecture as a whole, as has been done previously. The newly uncovered inter-lineage connections presented here suggest a novel hypothesis about the origins of the β-trefoil fold itself-namely, that it is a derived fold formed by \'budding\' from an Immunoglobulin-like β-sandwich protein. These results demonstrate how the evolution of a folded domain from a peptide need not be a signature of antiquity and underpin an emerging truth: few protein lineages escape nature\'s sewing table.

BACKGROUND: A lack of research on the association of trefoil factors (TFF) with gastric cancer and premalignant lesions (PML) in the general population is an important obstacle to the application of TFFs for gastric cancer screening. We aimed to analyze the association of TFFs with gastric cancer and PMLs in a general population.
METHODS: We evaluated 3,986 adults residing in Wuwei, China. We collected baseline characteristics and gastric cancer risk factors, including TFFs, endoscopic diagnosis, and pathologic information. Three logistic regression models were generated to analyze the association between TFFs and gastric cancer, as well as PMLs. Adjusted odds ratio (OR) and 95% confidence intervals (95% CI) were calculated to determine the strength of association.
RESULTS: Compared with pepsinogen (PG) and anti-Helicobacter pylori immunoglobulin G antibody (Hp-IgG), TFFs had significant association with gastric cancer and PMLs after adjusting for biomarkers and risk factors (P < 0.05). The ORs (95% CI) for TFF1 (1.67; 1.27-2.20), TFF2 (2.66; 2.01-3.51), and TFF3 (1.32; 1.00-1.74) were larger than the ORs for PGI (0.79; 0.61-1.03), PGI/II (1.00; 0.76-1.31), and Hp-IgG (0.99; 0.73-1.35) in the gastric cancer group. In the intestinal metaplasia (IM) group, not only the TFF3 serum level was the highest, but also the OR (1.92; 1.64-2.25) was the highest.
CONCLUSIONS: TFFs were associated with risk of gastric cancer and PMLs.
CONCLUSIONS: Serum TFFs can improve the screening of high-risk populations for gastric cancer.

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

Because most of animal viruses are enveloped, cytoplasmic entry of these viruses via fusion with cellular membrane initiates their invasion. However, the strategies in which host cells counteract cytoplasmic entry of such viruses are incompletely understood. Pore-forming toxin aerolysin-like proteins (ALPs) exist throughout the animal kingdom, but their functions are mostly unknown. In this study, we report that βγ-crystallin fused aerolysin-like protein and trefoil factor complex (βγ-CAT), an ALP and trefoil factor complex from the frog Bombina maxima, directly blocks enveloped virus invasion by interfering with cytoplasmic entry. βγ-CAT targeted acidic glycosphingolipids on the HSV type 1 (HSV-1) envelope to induce pore formation, as indicated by the oligomer formation of protein and potassium and calcium ion efflux. Meanwhile, βγ-CAT formed ring-like oligomers of ∼10 nm in diameter on the liposomes and induced dye release from liposomes that mimic viral envelope. Unexpectedly, transmission electron microscopy analysis showed that the βγ-CAT-treated HSV-1 was visibly as intact as the vehicle-treated HSV-1, indicating that βγ-CAT did not lyse the viral envelope. However, the cytoplasmic entry of the βγ-CAT-treated HSV-1 into HeLa cells was totally hindered. In vivo, topical application of βγ-CAT attenuated the HSV-1 corneal infection in mice. Collectively, these results uncovered that βγ-CAT possesses the capacity to counteract enveloped virus invasion with its featured antiviral-acting manner. Our findings will also largely help to illustrate the putative antiviral activity of animal ALPs.

The trefoil factor family proteins: TFF1, TFF2 and TFF3 are secreted by epithelial cells in the respiratory tract. Here, we explore circulating concentrations of the trefoil factors in relation to lung cancer, age and lung function. We included 751 patients suspected of lung cancer. Lung cancer diagnosis was based on data reported to a national database. Serum TFF1, TFF2 and TFF3 concentrations were measured by ELISA, and spirometry was performed within ±3 days of blood sampling. Forced expiratory volume in the first second (FEV1) in relation to forced vital capacity (FVC), FEV1/FVC (a parameter used to quantify reduced lung function) was recorded. Lung cancer was diagnosed in 163 (22%) patients. Circulating concentrations of TFF3 (p = .021), but not TFF1 and TFF2, were significantly elevated in cancer patients. All three trefoil factors showed an increase in concentration with increasing age (p < .001) and declining lung function (p < .004). In the present cohort, concentrations of all three peptides were elevated compared with previous results published for healthy individuals. In conclusion, we report higher concentrations of TFF3 in patients with lung cancer, while increasing age and reduced lung function are associated with increasing concentrations of all trefoil factors in this specific patient population. The results emphasize that age and lung function should be taken into consideration when evaluating concentrations of trefoil factors in patients. However, the increases in trefoil factor concentrations were relatively small, and consequently, it is unlikely that circulating trefoil factor concentrations may have a role in the diagnosis of lung cancer and lung function impairment.

Trefoil factor family peptides (TFF1, TFF2, TFF3), together with mucins, are typical exocrine products of mucous epithelia. Here, they act as a gastric tumor suppressor (TFF1) or they play different roles in mucosal innate immune defense (TFF2, TFF3). Minute amounts are also secreted as endocrine, e.g., by the immune and central nervous systems. As a hallmark, TFF peptides have different lectin activities, best characterized for TFF2, but also TFF1. Pathologically, ectopic expression occurs during inflammation and in various tumors. In this review, the role of TFF peptides during inflammation is discussed on two levels. On the one hand, the expression of TFF1-3 is regulated by inflammatory signals in different ways (upstream links). On the other hand, TFF peptides influence inflammatory processes (downstream links). The latter are recognized best in various Tff-deficient mice, which have completely different phenotypes. In particular, TFF2 is secreted by myeloid cells (e.g., macrophages) and lymphocytes (e.g., memory T cells), where it modulates immune reactions triggering inflammation. As a new concept, in addition to lectin-triggered activation, a hypothetical lectin-triggered inhibition of glycosylated transmembrane receptors by TFF peptides is discussed. Thus, TFFs are promising players in the field of glycoimmunology, such as galectins and C-type lectins.