High-level expression of human TFF3 in Escherichia coli

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 (TFF310-50) were susceptible to gastrointestinal degradation, revealing a gut-stable metabolite (TFF37-54; t1/2 > 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.

Extracellular production of recombinant sus scrofa trefoil factor 3 by Brevibacillus choshinensis

Trefoil factor 3 (TFF3) is involved in cell adhesion, motility and apoptosis, regulates mucosal immunity and maintains the functional integrity of intestinal epithelia. The upregulation of TFF3 expression in the weaning rat intestine attracted our interest. The present study hypothesized that TFF3 may serve a role in preventing diarrhea in weaning piglets, which is an important consideration in the pig farming industry. Previous recombinant TFF3 protein expression yields obtained from Escherichia coli were too low and the bioactivity of the protein was poor. Hence, this expression system was unsuitable for industrial applications. The present study explored the production of recombinant sus scrofa TFF3 in a Brevibacillus choshinensis (B. choshinensis) expression system, aiming to enhance the expression level of bioactive protein. To achieve this, the sus scrofa TFF3-encoding gene fragment was fused into an E. coli-Brevibacillus shuttle vector pNCMO2. High levels of TFF3 (30 mg/l) were produced and secreted into the B. choshinensis culture medium in soluble form with a molecular mass of 13.6 kDa and high immunoreactivity in western blotting. Thus, Brevibacillus may be used to produce useful mucosal factors for biochemical analyses and mucosal protection, and in industrial applications to produce novel inhibitors of diarrhea.

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.