Intestinal trefoil factor confers colonic epithelial resistance to apoptosis

Tissue distribution and expression dynamics of trefoil factor genes in the hydroid Hydractinia symbiolongicarpus

Proteins of the trefoil factor family (TFF) participate in mucosal repair and are formed by single or tandemly repeated trefoil domains. TFFs have been extensively studied in mammals and amphibians, but they have not been functionally characterized in other animals. Here we report the identification of two genes expressed in the hydroid Hydractinia symbiolongicarpus, predicted to encode trefoil domain-containing peptides, one with four trefoil domains in tandem and the other one with a trefoil domain flanked by two ShKT domains. Differential expression analyses by qPCR after an immune challenge and an induced mechanical damage, reveal that the former gene (hysyTFF) had no significant changes in expression after the inductions. However, the latter (hysyTFF-like) was overexpressed after three hours post immune challenge and was downregulated after the first hour post epithelial damage. Immunoblot analyses using specific IgY antibodies revealed that hysyTFF is secreted as a high molecular weight complex. Finally, whole mount immunofluorescence assays showed that hysyTFF was predominantly expressed in the endoderm of stolons and polyps, and sparsely in the ectoderm of both polyps and larvae. Thus, the tissue distribution and expression dynamics of trefoil factor genes in H. symbiolongicarpus suggest that hysyTFF is part of an ancient mechanism of epithelial restitution, and the newly reported hysyTFF-like might act as an immune effector gene, perhaps encoding an antibacterial peptide.

Genes involved in the cholecystokinin receptor signaling map were differentially expressed in the jejunum of steers with variation in residual feed intake

The jejunum is a critical site for nutrient digestion and absorption, and variation in its ability to take up nutrients within the jejunum is likely to affect feed efficiency. The purpose of this study was to determine differences in gene expression in the jejunum of beef steers divergent for residual feed intake (RFI) in one cohort of steers (Year 1), and to validate those genes in animals from a second study (Year 2). Steers from Year 1 (n = 16) were selected for high and low RFI. Jejunum mucosal tissue was obtained for RNA-seq. Thirty-two genes were differentially expressed (PFDR≤0.15), and five were over-represented in pathways including inflammatory mediator, cholecystokinin receptor (CCKR) signaling, and p38 MAPK pathways. Several differentially expressed genes (ALOX12, ALPI, FABP6, FABP7, FLT1, GSTA2, MEF2B, PDK4, SPP1, and TTF2) have been previously associated with RFI in other studies. Real-time qPCR was used to validate nine differentially expressed genes in the Year 1 steers used for RNA-seq, and in the Year 2 validation cohort. Six genes were validated as differentially expressed (P < 0.1) using RT-qPCR in the Year 1 population. In the Year 2 population, five genes displayed the same direction of expression as the Year 1 population and 3 were differentially expressed (P < 0.1). The CCKR pathway is involved in digestion, appetite control, and regulation of body weight making it a compelling candidate for feed efficiency in cattle, and the validation of these genes in a second population of cattle is suggestive of a role in feed efficiency.

The role of goblet cells in Crohn' s disease

The prevalence of Crohn's disease (CD), a subtype of inflammatory bowel disease (IBD), is increasing worldwide. The pathogenesis of CD is hypothesized to be related to environmental, genetic, immunological, and bacterial factors. Current studies have indicated that intestinal epithelial cells, including columnar, Paneth, M, tuft, and goblet cells dysfunctions, are strongly associated with these pathogenic factors. In particular, goblet cells dysfunctions have been shown to be related to CD pathogenesis by direct or indirect ways, according to the emerging studies. The mucus barrier was established with the help of mucins secreted by goblet cells. Not only do the mucins mediate the mucus barrier permeability and bacterium selection, but also, they are closely linked with the endothelial reticulum stress during the synthesis process. Goblet cells also play a vital role in immune response. It was indicated that goblet cells take part in the antigen presentation and cytokines secretion process. Disrupted goblet cells related immune process were widely discovered in CD patients. Meanwhile, dysbiosis of commensal and pathogenic microbiota can induce myriad immune responses through mucus and goblet cell-associated antigen passage. Microbiome dysbiosis lead to inflammatory reaction against pathogenic bacteria and abnormal tolerogenic response. All these three pathways, including the loss of mucus barrier function, abnormal immune reaction, and microbiome dysbiosis, may have independent or cooperative effect on the CD pathogenesis. However, many of the specific mechanisms underlying these pathways remain unclear. Based on the current understandings of goblet cell's role in CD pathogenesis, substances including butyrate, PPARγagonist, Farnesoid X receptor agonist, nuclear factor-Kappa B, nitrate, cytokines mediators, dietary and nutrient therapies were all found to have potential therapeutic effects on CD by regulating the goblet cells mediated pathways. Several monoclonal antibodies already in use for the treatment of CD in the clinical settings were also found to have some goblet cells related therapeutic targets. In this review, we introduce the disease-related functions of goblet cells, their relationship with CD, their possible mechanisms, and current CD treatments targeting goblet cells.

Delayed recanalization reduced neuronal apoptosis and neurological deficits by enhancing liver-derived trefoil factor 3-mediated neuroprotection via LINGO2/EGFR/Src signaling pathway after middle cerebral artery occlusion in rats

Delayed recanalization at days or weeks beyond the therapeutic window was shown to improve functional outcomes in acute ischemic stroke (AIS) patients. However, the underlying mechanisms remain unclear. Previous preclinical study reported that trefoil factor 3 (TFF3) was secreted by liver after cerebral ischemia and acted a distant neuroprotective factor. Here, we investigated the liver-derived TFF3-mediated neuroprotective mechanism enhanced by delayed recanalization after AIS. A total of 327 male Sprague-Dawley rats and the model of middle cerebral artery occlusion (MCAO) with permanent occlusion (pMCAO) or with delayed recanalization at 3 d post-occlusion (rMCAO) were used. Partial hepatectomy was performed within 5 min after MCAO. Leucine-rich repeat and immunoglobulin-like domain-containing nogo receptor-interacting protein 2 (LINGO2) siRNA was administered intracerebroventricularly at 48 h after MCAO. Recombinant rat TFF3 (rr-TFF3, 30 μg/Kg) or recombinant rat epidermal growth factor (rr-EGF, 100 μg/Kg) was administered intranasally at 1 h after recanalization, and EGFR inhibitor Gefitinib (75 mg/Kg) was administered intranasally at 30 min before recanalization. The evaluation of outcomes included neurobehavior, ELISA, western blot and immunofluorescence staining. TFF3 in hepatocytes and serum were upregulated in a similar time-dependent manner after MCAO. Compared to pMCAO, delayed recanalization increased brain TFF3 levels and attenuated brain damage with the reduction in neuronal apoptosis, infarct volume and neurological deficits. Partial hepatectomy reduced TFF3 levels in serum and ipsilateral brain hemisphere, and abolished the benefits of delayed recanalization on neuronal apoptosis and neurobehavioral deficits in rMCAO rats. Intranasal rrTFF3 treatment reversed the changes associated with partial hepatectomy. Delayed recanalization after MCAO increased the co-immunoprecipitation of TFF3 and LINGO2, as well as expressions of p-EGFR, p-Src and Bcl-2 in the brain. LINGO2 siRNA knockdown or EGFR inhibitor reversed the effects of delayed recanalization on apoptosis and brain expressions of LINGO2, p-EGFR, p-Src and Bcl-2 in rMCAO rats. EGFR activator abolished the deleterious effects of LINGO2 siRNA. In conclusion, our investigation demonstrated for the first time that delayed recanalization may enhance the entry of liver-derived TFF3 into ischemic brain upon restoring blood flow after MCAO, which attenuated neuronal apoptosis and neurological deficits at least in part via activating LINGO2/EGFR/Src pathway.

Protective Effect of Citrus Medica limonum Essential Oil against Escherichia coli K99-Induced Intestinal Barrier Injury in Mice

Citrus Medica limonum essential oil (LEO) has been reported to have antibacterial and anti-inflammatory activities, but its protective effect in the intestine remains unknown. In this study, we researched the protective effects of LEO in relation to intestinal inflammation induced by E. coli K99. The mice were pretreated with 300, 600, and 1200 mg/kg LEO and then stimulated with E. coli K99. The results showed that E. coli K99 caused immune organ responses, intestinal tissue injury, and inflammation. LEO pretreatment dose-dependently alleviated these changes by maintaining a low index in the thymus and spleen and producing a high content of immunoglobulin A, G, and M (IgA, IgG, and IgM) and low content of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6). Intestinal integrity as a consequence of the LEO pretreatment may be related to the high mRNA expression of intestinal trefoil factor (ITF) and the low mRNA expression of transforming growth factor-β1 (TGF-β1). Conclusively, an LEO pretreatment can alleviate E. coli K99-induced diarrhea, immune organ response, and body inflammation in mice by reducing the levels of inflammatory cytokines and improving the levels of immunoglobulin, and the intestinal integrity remained highest when maintaining the high mRNA expression of ITF and keeping the mRNA expression of TGF-β1 low in the intestinal tissue.

Diagnostic utility of trefoil factor families for the early detection of lung cancer and their correlation with tissue expression

Trefoil factors (TFFs) are upregulated in numerous types of cancer, including those of the breast, the colon, the lung and the pancreas, suggesting their potential utility as biomarkers for screening. In the present study, the clinical relevance of serum or urinary TFFs as biomarkers were comprehensively evaluated and the correlation with TFF expression levels in lung cancer tissue was examined. Serum and urine were collected from 199 patients with lung cancer and 198 healthy individuals. Concentrations of serum and urinary TFF1, TFF2 and TFF3 were measured using ELISA and the potential of TFF levels to discriminate between cancer and non-cancer samples was evaluated. In 100 of the cancer cases, expression of TFF1-3 was analyzed using immunohistochemical staining of paraffin sections. Furthermore, the relationship between TFF levels and clinicopathological factors among these cancer cases was analyzed using immunohistochemistry of tissue specimens, quantified and statistically analyzed. While serum levels of all TFFs measured using ELISA were significantly higher in patients with lung cancer compared with those in healthy individuals, urinary TFFs were lower. Areas under the curve (AUC) of the receiver operating characteristic curves for serum/urinary TFF1, TFF2 and TFF3 were 0.709/0.594, 0.722/0.501 and 0.663/0.665, respectively. Furthermore, the combination of serum TFF1, TFF2, TFF3 and urinary TFF1 and TFF3 demonstrated the highest AUC (0.826). In the clinicopathological analysis, serum TFF1 was higher in the early pathological T-stage (pTis/1/2) compared with the later stage (pT3/4) and TFF2 was higher in the pN0/1 than the pN2 group. With regards to the histological types, urinary TFF1 was higher in squamous cell carcinoma than adenocarcinoma (AC), but TFF2 tended to be higher in AC. Using immunohistochemical analysis, although TFF1 and TFF3 expression showed positive correlation with serum concentrations, TFF2 was inversely correlated. In conclusion, serum and urinary TFF levels are promising predictive biomarkers, and their measurements provide a useful in vivo and non-invasive diagnostic screening tool. In particular, TFF1 and TFF3 could be surrogate markers of clinicopathological profiles of human lung cancer.

Trefoil factor 3: New highlights in chronic kidney disease research

Trefoil factor 3 (TFF3, also known as intestinal trefoil factor) is a small-molecule peptide containing a typical trefoil structure. TFF3 has several biological effects, such as wound healing, immune regulation, neuroprotection, and cell migration and proliferation promotion. Although TFF3 binding sites were identified in rat kidneys more than a decade ago, the specific effects of this small-molecule peptide on kidneys remain unclear. Until recently, much of the research on TFF3 in the kidney field has focused exclusively on its role as a biomarker. Notably, a large prospective randomized study of patients with 29 common clinical diseases revealed that chronic kidney disease (CKD) was associated with the highest serum TFF3 levels, which were 3-fold higher than in acute gastroenteritis, which had the second-highest levels. Examination of each stage of CKD revealed that urine and serum TFF3 levels significantly increased with the progression of CKD. These results suggest that the role of TFF3 in CKD needs further research. The present review summarizes the renal physiological expression, biological functions, and downstream signaling of TFF3, as well as the upstream events that lead to high expression of TFF3 in CKD.

Downregulation of the Tumor Suppressor TFF1 Is Required during Induction of Colon Cancer Progression by L1

Simple Summary

Aberrant activation of Wnt/β-catenin signaling and the subsequent induction of downstream target genes is a hallmark of colorectal cancer (CRC) development. Previously, we found that overexpression of the immunoglobulin-like cell adhesion receptor L1CAM (L1), a target of the Wnt/β-catenin pathway, confers enhanced proliferation, motility, tumorigenesis, and liver metastasis in CRC cells. Transcriptomic and proteomic analyses revealed changes in both pro-tumorigenic and potential tumor-suppressor genes in L1-overexpressing CRC cells. We wished to identify such tumor suppressor/s, and found that trefoil family factor 1 (TFF1) was involved in L1-mediated CRC progression. TFF1 overexpression suppressed the growth, motility and tumorigenesis of L1-expressing CRC cells by inhibiting the NF-κB pathway. In human CRC tissue, TFF1-positive staining was evident in goblet cells of the normal mucosa, while in CRC tissue, TFF1 expression was lost in >50% of the tumor samples. Our results support a tumor-suppressor role of TFF1 in human CRC, and we suggest that TFF1 could be used for CRC detection and as a novel therapeutic target in L1-mediated CRC.

Abstract

The immunoglobulin family cell adhesion receptor L1 is induced in CRC cells at the invasive front of the tumor tissue, and confers enhanced proliferation, motility, tumorigenesis, and liver metastasis. To identify putative tumor suppressors whose expression is downregulated in L1-expressing CRC cells, we blocked the L1–ezrin–NF-κB signaling pathway and searched for genes induced under these conditions. We found that TFF1, a protein involved in protecting the mucus epithelial layer of the colon, is downregulated in L1-expressing cells and displays characteristics of a tumor suppressor. Overexpression of TFF1 in L1-transfected human CRC cells blocks the pro-tumorigenic and metastatic properties conferred by L1 by suppressing NF-κB signaling. Immunohistochemical analyses revealed that human CRC tissue samples often lose the expression of TFF1, while the normal mucosa displays TFF1 in goblet cells. Identifying TFF1 as a tumor suppressor in CRC cells could provide a novel marker for L1-mediated CRC development and a potential target for therapy.

Monomerization of Homodimeric Trefoil Factor 3 (TFF3) by an Aminonitrile Compound Inhibits TFF3-Dependent Cancer Cell Survival

Trefoil factor 3 (TFF3) is a secreted protein with an established oncogenic function and a highly significant association with clinical progression of various human malignancies. Herein, a novel small molecule that specifically targets TFF3 homodimeric functions was identified. Utilizing the concept of reversible covalent interaction, 2-amino-4-(4-(6-fluoro-5-methylpyridin-3-yl)phenyl)-5-oxo-4H,5H-pyrano[3,2-c]chromene-3-carbonitrile (AMPC) was identified as a molecule that interacted with TFF3. AMPC monomerized the cellular and secreted TFF3 homodimer at the cysteine (Cys)57-Cys57 residue with subsequent more rapid degradation of the generated TFF3 monomers. Hence, AMPC treatment also resulted in cellular depletion of TFF3 with consequent decreased cell viability in various human carcinoma-derived TFF3 expressing cell lines, including estrogen receptor positive (ER+) mammary carcinoma (MC). AMPC treatment of TFF3 expressing ER+ MC cells significantly suppressed total cell number in a dose-dependent manner. Consistently, exposure of TFF3 expressing ER+ MC cells to AMPC decreased soft agar colony formation, foci formation, and growth in suspension culture and inhibited growth of preformed colonies in 3D Matrigel. AMPC increased apoptosis in TFF3 expressing ER+ MC cells associated with decreased activity of EGFR, p38, STAT3, AKT, and ERK, decreased protein levels of CCND1, CCNE1, BCL2, and BCL-XL, and increased protein levels of TP53, CDKN1A, CASP7, and CASP9. siRNA-mediated depletion of TFF3 expression in ER+ MC cells efficiently abrogated AMPC-stimulated loss of cell viability and CASPASE 3/7 activities. Furthermore, in mice bearing ER+ MC cell-generated xenografts, AMPC treatment significantly impeded xenograft growth. Hence, AMPC exemplifies a novel mechanism by which small molecule drugs may inhibit a dimeric oncogenic protein and provides a strategy to impede TFF3-dependent cancer progression.

A gut-centric view of aging: Do intestinal epithelial cells contribute to age-associated microbiota changes, inflammaging, and immunosenescence?

Intestinal epithelial cells (IECs) serve as both a physical and an antimicrobial barrier against the microbiota, as well as a conduit for signaling between the microbiota and systemic host immunity. As individuals age, the balance between these systems undergoes a myriad of changes due to age-associated changes to the microbiota, IECs themselves, immunosenescence, and inflammaging. In this review, we discuss emerging data related to age-associated loss of intestinal barrier integrity and posit that IEC dysfunction may play a central role in propagating age-associated alterations in microbiota composition and immune homeostasis.

Sympathetic Innervation Modulates Mucosal Immune Homeostasis and Epithelial Host Defense

Intestinal mucosal cells, such as resident macrophages and epithelial cells, express adrenergic receptors and are receptive to norepinephrine, the primary neurotransmitter of the sympathetic nervous system (SNS). It has been suggested that the SNS affects intestinal immune activity in conditions, such as inflammatory bowel disease; however, the underlying mechanisms remain ambiguous. Here, we investigated the effect of SNS on mucosal immune and epithelial cell functions. We employed 6-OHDA-induced sympathetic denervation (cSTX) to characterize muscularis-free mucosal transcriptomes by RNA-seq and qPCR, and quantified mucosal immune cells by flow cytometry. The role of norepinephrine and cytokines on epithelial functions was studied using small intestinal organoids. cSTX increased the presence of activated CD68⁺CD86⁺ macrophages and monocytes in the mucosa. In addition, through transcriptional profiling, the proinflammatory cytokines IL-1β, TNF-α, and IFN-γ were induced, while Arg-1 and CD163 expression was reduced. Further, cSTX increased intestinal permeability in vivo and induced genes involved in barrier integrity and antimicrobial defense. In intestinal organoids, similar alterations were observed after treatment with proinflammatory cytokines, but not norepinephrine. We conclude that a loss in sympathetic input induces a proinflammatory mucosal state, leading to reduced epithelial barrier functioning and enhanced antimicrobial defense. This implies that the SNS might be required to maintain intestinal immune functions during homeostasis.

Augmented leptin-induced trefoil factor 3 expression and epidermal growth factor receptor transactivation differentially influences neoplasia progression in the stomach and colorectum of dietary fat-induced obese mice

Obesity is a risk factor for gastrointestinal malignancies and tumors. However, which factors either protect or predispose the gastrointestinal organs to high-fat diet (HFD)-induced neoplasia remains unclear. Here, we demonstrate that HFD impacts the stomach to a greater extent as compared to the colorectum, resulting in leptin receptor (LepR) signaling-mediated neoplasia in the tissues. HFD activated leptin signaling, which in turn, accelerates the pathogenesis in the gastric mucosa more than that in the colorectum along with ectopic TFF3 expression. Moreover, in the stomach, higher levels of phosphorylated epidermal growth factor receptor (EGFR) in addition to the activation of STAT3 and Akt were observed as compared to the colorectum. The mice with LepR deletion in the gastrointestinal epithelium exhibited a suppressed induction of leptin, TFF3, and phosphorylated EGFR in the stomach, whereas the levels in the colorectum were insignificant. In co-transfected COS-7 cells with LepR and EGFR plasmid DNA, leptin transactivated EGFR to accelerate TFF3 induction along with activation of STAT3, ERK1/2, Akt, and PI3K p85/p55. Furthermore, TFF3 could bind to EGFR but did not transactivate LepR. Leptin-induced TFF3 induction was markedly suppressed by inhibitors of PI3K (LY294002) and EGFR (Erlotinib). Together, these results suggest a novel role of LepR-mediated signaling in transactivating EGFR that leads to TFF3 expression via the PI3K-Akt pathway. Therefore, this study sheds light on the identification of potentially new therapeutic targets for the treatment of pre-cancerous symptoms in stomach and colorectum.

C/EBPα Epigenetically Modulates TFF1 Expression via mC-6 Methylation in the Jejunum Inflammation Induced by a Porcine Coronavirus

Porcine epidemic diarrhea virus (PEDV) is an emerging coronavirus which causes acute diarrhea and destroys gastrointestinal barrier function in neonatal pigs. Trefoil factor 1 (TFF1) is a protective peptide for maintaining the integrity of gastrointestinal mucosa and reducing intestinal inflammation. However, its role in protecting intestinal epithelium against PEDV infection is still unclear. In this study, we discovered that TFF1 expression was activated in the jejunum of pigs with PEDV infection and TFF1 is required for the growth of porcine intestinal epithelial cells. For instance, inhibited cell proliferation and cell arrest were observed when TFF1 is genetically knocked-out using CRISPR-Cas9. Additionally, TFF1 depletion increased viral copy number and PEDV titer, along with the elevated genes involved in antiviral and inflammatory cytokines. The decreased TFF1 mRNA expression is in line with hypermethylation on the gene promoter. Notably, the strong interactions of protein-DNA complexes containing CCAAT motif significantly increased C/EBPα accessibility, whereas hypermethylation of mC-6 loci decreased C/EBPα binding occupancies in TFF1 promoter. Overall, our findings show that PEDV triggers the C/EBPα-mediated epigenetic regulation of TFF1 in intestine epithelium and facilitates host resistance to PEDV and other Coronavirus infections.

The role of γδ T cells in the interaction between commensal and pathogenic bacteria in the intestinal mucosa

The intestinal mucosa is an important structure involved in resistance to pathogen infection. It is mainly composed of four barriers, which have different but interrelated functions. Pathogenic bacteria can damage these intestinal mucosal barriers. Here, we mainly review the mechanisms of pathogen damage to biological barriers. Most γδ T cells are located on the surface of the intestinal mucosa, with the ability to migrate and engage in crosstalk with microorganisms. Commensal bacteria are involved in the activation and migration of γδ T cells to monitor the invasion of pathogens. Pathogen invasion alters the migration pattern of γδ T cells. γδ T cells accelerate pathogen clearance and limit opportunistic invasion of commensal bacteria. By discussing these interactions among γδ T cells, commensal bacteria and pathogenic bacteria, we suggest that γδ T cells may link the interactions between commensal bacteria and pathogenic bacteria.

Effect of Early Pathogenic Escherichia coli Infection on the Intestinal Barrier and Immune Function in Newborn Calves

We studied the effect of early pathogenic Escherichia coli infection on newborn calves’ intestinal barrier and immune function. A total of 64 newborn Holstein male calves (40–43 kg) were divided into two groups: normal (NG) and test (TG), each with 32 heads. At the beginning of the experiment, the TG calves were orally administered pathogenic E. coli O1 (2.5 × 10¹¹ CFU/mL, 100 mL) to establish a calf diarrhea model. In contrast, the NG calves were given the same amount of normal saline. During the 30 d trial period, the feeding and management of the two groups remained constant. Enzyme-linked immunosorbent assay, quantification PCR, and high-throughput 16S rRNA sequencing technology were used to detect indicators related to the intestinal barrier and immune function in the calf serum and tissues. Pathogenic E. coli O1 had a significant effect on calf diarrhea in the TG; it increased the bovine diamine oxidase (P < 0.05) and endotoxin levels in the serum and decreased (P < 0.05) the intestinal trefoil factor (P < 0.05), Occludin, Claudin-1, and Zonula Occludens 1 (ZO-1) levels in the colon tissue, as well as downregulated the mRNA expression of Occludin, Claudin-1,and ZO-1 in the colon mucosa, leading to increased intestinal permeability and impaired intestinal barrier function. Additionally, pathogenic E. coli had a significant impact on the diversity of colonic microbial flora, increasing the relative abundance of Proteobacteria at the phylum level and decreasing the levels of Firmicutes and Bacteroides. At the genus level, the relative abundance of Escherichia and Shigella in the TG increased significantly (P < 0.05), whereas that of Bacteroides, Butyricicoccus, Rikenellaceae_RC9_gut_group, Blautia, and Lactobacillus was significantly decreased (P < 0.05). In addition, the level of IL-6 in the serum of the TG calves was significantly increased (P < 0.05), whereas the IL-4 and IL-10 levels were significantly decreased (P < 0.05), compared to those in the NG calves. Thus, pathogenic E. coli induced diarrhea early in life disrupts intestinal barrier and impairs immune function in calves.

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

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

CD147 receptor is essential for TFF3-mediated signaling regulating colorectal cancer progression

Major gaps in understanding the molecular mechanisms of colorectal cancer (CRC) progression and intestinal mucosal repair have hampered therapeutic development for gastrointestinal disorders. Trefoil factor 3 (TFF3) has been reported to be involved in CRC progression and intestinal mucosal repair; however, how TFF3 drives tumors to become more aggressive or metastatic and how TFF3 promotes intestinal mucosal repair are still poorly understood. Here, we found that the upregulated TFF3 in CRC predicted a worse overall survival rate. TFF3 deficiency impaired mucosal restitution and adenocarcinogenesis. CD147, a membrane protein, was identified as a binding partner for TFF3. Via binding to CD147, TFF3 enhanced CD147-CD44s interaction, resulting in signal transducer and activator of transcription 3 (STAT3) activation and prostaglandin G/H synthase 2 (PTGS2) expression, which were indispensable for TFF3-induced migration, proliferation, and invasion. PTGS2-derived PGE2 bound to prostaglandin E2 receptor EP4 subtype (PTGER4) and contributed to TFF3-stimulated CRC progression. Solution NMR studies of the TFF3-CD147 interaction revealed the key residues critical for TFF3 binding and the induction of PTGS2 expression. The ability of TFF3 to enhance mucosal restitution was weakened by a PTGS2 inhibitor. Blockade of TFF3-CD147 signaling using competitive inhibitory antibodies or a PTGS2 inhibitor reduced CRC lung metastasis in mice. Our findings bring strong evidence that CD147 is a novel receptor for TFF3 and PTGS2 signaling is critical for TFF3-induced mucosal restitution and CRC progression, which widens and deepens the understanding of the molecular function of trefoil factors.

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.

LSD1 and Aberrant DNA Methylation Mediate Persistence of Enteroendocrine Progenitors That Support BRAF-Mutant Colorectal Cancer

Despite the connection of secretory cells, including goblet and enteroendocrine (EEC) cells, to distinct mucus-containing colorectal cancer histologic subtypes, their role in colorectal cancer progression has been underexplored. Here, our analysis of The Cancer Genome Atlas (TCGA) and single-cell RNA-sequencing data demonstrates that EEC progenitor cells are enriched in BRAF-mutant colorectal cancer patient tumors, cell lines, and patient-derived organoids. In BRAF-mutant colorectal cancer, EEC progenitors were blocked from differentiating further by DNA methylation and silencing of NEUROD1, a key gene required for differentiation of intermediate EECs. Mechanistically, secretory cells and the factors they secrete, such as trefoil factor 3, promoted colony formation and activation of cell survival pathways in the entire cell population. Lysine-specific demethylase 1 (LSD1) was identified as a critical regulator of secretory cell specification in vitro and in a colon orthotopic xenograft model, where LSD1 loss blocks formation of EEC progenitors and reduces tumor growth and metastasis. These findings reveal an important role for EEC progenitors in supporting colorectal cancer. SIGNIFICANCE: This study establishes enteroendocrine progenitors as a targetable population that promotes BRAF-mutant colorectal cancer and can be blocked by LSD1 inhibition to suppress tumor growth.

Rotavirus infection induces glycan availability to promote ileum-specific changes in the microbiome aiding rotavirus virulence

Multiple studies have identified changes within the gut microbiome in response to diarrheal-inducing bacterial pathogens. However, examination of the microbiome in response to viral pathogens remains understudied. Compounding this, many studies use fecal samples to assess microbiome composition; which may not accurately mirror changes within the small intestine, the primary site for most enteric virus infections. As a result, the functional significance of small intestinal microbiome shifts during infection is not well defined. To address these gaps, rotavirus-infected neonatal mice were examined for changes in bacterial community dynamics, host gene expression, and tissue recovery during infection. Profiling bacterial communities using 16S rRNA sequencing suggested significant and distinct changes in ileal communities in response to rotavirus infection, with no significant changes for other gastrointestinal (GI) compartments. At 1-d post-infection, we observed a loss in Lactobacillus species from the ileum, but an increase in Bacteroides and Akkermansia, both of which exhibit mucin-digesting capabilities. Concomitant with the bacterial community shifts, we observed a loss of mucin-filled goblet cells in the small intestine at d 1, with recovery occurring by d 3. Rotavirus infection of mucin-producing cell lines and human intestinal enteroids (HIEs) stimulated release of stored mucin granules, similar to in vivo findings. In vitro, incubation of mucins with Bacteroides or Akkermansia members resulted in significant glycan degradation, which altered the binding capacity of rotavirus in silico and in vitro. Taken together, these data suggest that the response to and recovery from rotavirus-diarrhea is unique between sub-compartments of the GI tract and may be influenced by mucin-degrading microbes.

Trefoil Factor Family (TFF) Peptides and Their Diverse Molecular Functions in Mucus Barrier Protection and More: Changing the Paradigm

Trefoil factor family peptides (TFF1, TFF2, TFF3) are typically co-secreted together with mucins. Tff1 represents a gastric tumor suppressor gene in mice. TFFs are also synthesized in minute amounts in the immune and central nervous systems. In mucous epithelia, they support rapid repair by enhancing cell migration ("restitution") via their weak chemotactic and anti-apoptotic effects. For a long time, as a paradigm, this was considered as their major biological function. Within recent years, the formation of disulfide-linked heterodimers was documented for TFF1 and TFF3, e.g., with gastrokine-2 and IgG Fc binding protein (FCGBP). Furthermore, lectin activities were recognized as enabling binding to a lipopolysaccharide of Helicobacter pylori (TFF1, TFF3) or to a carbohydrate moiety of the mucin MUC6 (TFF2). Only recently, gastric TFF1 was demonstrated to occur predominantly in monomeric forms with an unusual free thiol group. Thus, a new picture emerged, pointing to diverse molecular functions for TFFs. Monomeric TFF1 might protect the gastric mucosa as a scavenger for extracellular reactive oxygen/nitrogen species. Whereas, the TFF2/MUC6 complex stabilizes the inner layer of the gastric mucus. In contrast, the TFF3-FCGBP heterodimer (and also TFF1-FCGBP) are likely part of the innate immune defense of mucous epithelia, preventing the infiltration of microorganisms.

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

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

Transcriptomic and computational analysis identified LPA metabolism, KLHL14 and KCNE3 as novel regulators of Epithelial-Mesenchymal Transition

Epithelial-mesenchymal transition (EMT) is a complex biological program between physiology and pathology. Here, amniotic epithelial cells (AEC) were used as in vitro model of transiently inducible EMT in order to evaluate the transcriptional insights underlying this process. Therefore, RNA-seq was used to identify the differentially expressed genes and enrichment analyses were carried out to assess the intracellular pathways involved. As a result, molecules exclusively expressed in AEC that experienced EMT (GSTA1-1 and GSTM3) or when this process is inhibited (KLHL14 and KCNE3) were identified. Lastly, the network theory was used to obtain a computational model able to recognize putative controller genes involved in the induction and in the prevention of EMT. The results suggested an opposite role of lysophosphatidic acid (LPA) synthesis and degradation enzymes in the regulation of EMT process. In conclusion, these molecules may represent novel EMT regulators and also targets for developing new therapeutic strategies.

Human Synovia Contains Trefoil Factor Family (TFF) Peptides 1-3 Although Synovial Membrane Only Produces TFF3: Implications in Osteoarthritis and Rheumatoid Arthritis

Objective: Trefoil factor family peptide 3 (TFF3) has been shown to support catabolic functions in cases of osteoarthritis (OA). As in joint physiology and diseases such as OA, the synovial membrane (SM) of the joint capsule also plays a central role. We analyze the ability of SM to produce TFF compare healthy SM and its secretion product synovial fluid (SF) with SM and SF from patients suffering from OA or rheumatoid arthritis (RA). Methods: Real-time PCR and ELISA were used to measure the expression of TFFs in healthy SM and SM from patients suffering from OA or RA. For tissue localization, we investigated TFF1-3 in differently aged human SM of healthy donors by means of immunohistochemistry, real-time PCR and Western blot. Results: Only TFF3 but not TFF1 and -2 was expressed in SM from healthy donors as well as cases of OA or RA on protein and mRNA level. In contrast, all three TFFs were detected in all samples of SF on the protein level. No significant changes were observed for TFF1 at all. TFF2 was significantly upregulated in RA samples in comparison to OA samples. TFF3 protein was significantly downregulated in OA samples in comparison to healthy samples and cases of RA significantly upregulated compared to OA. In contrast, in SM TFF3 protein was not significantly regulated. Conclusion: The data demonstrate the production of TFF3 in SM. Unexpectedly, SF contains all three known TFF peptides. As neither articular cartilage nor SM produce TFF1 and TFF2, we speculate that these originate with high probability from blood serum.

TFF3 interacts with LINGO2 to regulate EGFR activation for protection against colitis and gastrointestinal helminths

Intestinal epithelial cells (IEC) have important functions in nutrient absorption, barrier integrity, regeneration, pathogen-sensing, and mucus secretion. Goblet cells are a specialized cell type of IEC that secrete Trefoil factor 3 (TFF3) to regulate mucus viscosity and wound healing, but whether TFF3-responsiveness requires a receptor is unclear. Here, we show that leucine rich repeat receptor and nogo-interacting protein 2 (LINGO2) is essential for TFF3-mediated functions. LINGO2 immunoprecipitates with TFF3, co-localizes with TFF3 on the cell membrane of IEC, and allows TFF3 to block apoptosis. We further show that TFF3-LINGO2 interactions disrupt EGFR-LINGO2 complexes resulting in enhanced EGFR signaling. Excessive basal EGFR activation in Lingo2 deficient mice increases disease severity during colitis and augments immunity against helminth infection. Conversely, TFF3 deficiency reduces helminth immunity. Thus, TFF3-LINGO2 interactions de-repress inhibitory LINGO2-EGFR complexes, allowing TFF3 to drive wound healing and immunity.

Mouse trefoil factor 3 ameliorated high-fat-diet-induced hepatic steatosis via increasing peroxisome proliferator-activated receptor-α-mediated fatty acid oxidation

Hepatic trefoil factor 3 (Tff3) was identified as a potential protein for the treatment of diabetes, yet the effect of Tff3 on nonalcoholic fatty liver disease (NAFLD) has never been explored. Here, we found that the expression of hepatic Tff3 was significantly decreased in NAFLD mice models, suggesting that Tff3 was a potential marker gene for NAFLD. Restoring the expression of Tff3 in the liver of NAFLD mice, including diabetic (db), obese (ob/ob), and diet-induced obese mice, with adenovirus-mediated Tff3 (Ad-Tff3) apparently attenuates the fatty liver phenotype. In contrast, adenovirus-mediated knockdown of Tff3 (Ad-shTff3) in C57BL/6J mice results in an obvious fatty liver phenotype. Furthermore, our molecular experiments indicated that hepatic Tff3 could alleviate hepatic steatosis via upregulating the expression of peroxisome proliferator-activated receptor-α (PPARα) directly, thereby enhancing the fatty acid oxidation process in the liver. Notably, we found that Tff3 attenuates the fatty liver phenotype independent of modulation of lipogenesis and improves the capacity of anti-inflammation. Overall, our results suggested that hepatic Tff3 could be effectively used as a potential therapy target for the treatment of NAFLD.

Epithelial Cells as a Transmitter of Signals From Commensal Bacteria and Host Immune Cells

Intestinal epithelial cells (IECs) are non-hematopoietic cells that form a physical barrier against external antigens. Recent studies indicate that IECs have pleiotropic functions in the regulation of luminal microbiota and the host immune system. IECs produce various immune modulatory cytokines and chemokines in response to commensal bacteria and contribute to developing the intestinal immune system. In contrast, IECs receive cytokine signals from immune cells and produce various immunological factors against luminal bacteria. This bidirectional function of IECs is critical to regulate homeostasis of microbiota and the host immune system. Disruption of the epithelial barrier leads to detrimental host diseases such as inflammatory bowel disease, colonic cancer, and pathogenic infection. This review provides an overview of the functions and physiology of IECs and highlights their bidirectional functions against luminal bacteria and immune cells, which contribute to maintaining gut homeostasis.

Current Findings on Gut Microbiota Mediated Immune Modulation against Viral Diseases in Chicken

Chicken gastrointestinal tract is an important site of immune cell development that not only regulates gut microbiota but also maintains extra-intestinal immunity. Recent studies have emphasized the important roles of gut microbiota in shaping immunity against viral diseases in chicken. Microbial diversity and its integrity are the key elements for deriving immunity against invading viral pathogens. Commensal bacteria provide protection against pathogens through direct competition and by the production of antibodies and activation of different cytokines to modulate innate and adaptive immune responses. There are few economically important viral diseases of chicken that perturb the intestinal microbiota diversity. Disruption of microbial homeostasis (dysbiosis) associates with a variety of pathological states, which facilitate the establishment of acute viral infections in chickens. In this review, we summarize the calibrated interactions among the microbiota mediated immune modulation through the production of different interferons (IFNs) ILs, and virus-specific IgA and IgG, and their impact on the severity of viral infections in chickens. Here, it also shows that acute viral infection diminishes commensal bacteria such as Lactobacillus, Bifidobacterium, Firmicutes, and Blautia spp. populations and enhances the colonization of pathobionts, including E. coli, Shigella, and Clostridial spp., in infected chickens.

Possible application of trefoil factor family peptides in gastroesophageal reflux and Barrett's esophagus

Gastroesophageal reflux disease (GERD) is a chronic disorder of the digestive tract characterised mainly by a heartburn. Being one of the most common gastrointestinal diseases, the prevalence of GERD reaches up to 25.9% in Europe. Barrett's esophagus (BE) is an acquired condition characterized by the replacement of the normal stratified squamous epithelium with metaplastic columnar epithelium. BE is believed to develop mainly from chronic GERD and is the most important risk factor of esophageal adenocarcinoma. Despite the availability of drugs such as proton pomp inhibitors and antacids, GERD is still a burden to local economy and impairs health-related quality of life in patients. Also, the endoscopic surveillance in patients with BE is burdensome and expensive what drives the need for biomarker of intestinal metaplasia and dysplasia. Trefoil factor family (TFF), consisting of TFF1, TFF2 and TFF3 peptides is gaining more and more attention due to its unique biochemical features and numerous functions. In this review the role of TFF1, TFF2 and TFF3 as potential treatment option and/or biomarker in the upper GI tract is discussed with particular focus on GERD and BE.

Cilostazol against 2,4,6‐trinitrobenzene sulfonic acid‐induced colitis: Effect on tight junction, inflammation, and apoptosis

Background

Aim

Methods

Results

Conclusion

Influence of Growth Factors on the Development of Necrotizing Enterocolitis

Growth factors have important roles in gastrointestinal tract development, maintenance, and response to injury. Various experiments have been used to demonstrate growth factor influence in multiple disease processes. These studies demonstrated enhancement of mucosal proliferation, intestinal motility, immune modulation, and many other beneficial effects. Select growth factors, including epidermal growth factor and heparin-binding epidermal growth factor like growth factor, demonstrate some beneficial effects in experimental and clinical intestinal injury demonstrated in necrotizing enterocolitis. The roles of glucagon-like peptide 2, insulin-like growth factor 1, erythropoietin, growth hormone, and hepatocyte growth factor in necrotizing enterocolitis are summarized in this article.

Tumor suppressor miR-215 counteracts hypoxia-induced colon cancer stem cell activity

Cancer stem cells, also known as tumor-initiating cells (TICs), are a population of aggressive and self-renewing cells that are responsible for the initiation and progression of many cancers, including colorectal carcinoma. Intratumoral hypoxia, i.e. reduced oxygen supply following uncontrolled proliferation of cancer cells, is thought to support TIC activity by inducing specific hypoxia-responsive mechanisms that are not yet entirely understood. Using previously established and fully characterized patient-derived TIC cultures, we could observe increased sphere and colony formation under hypoxic conditions. Mechanistically, microRNA (miRNA)-profiling experiments allowed us to identify miR-215 as one of the main hypoxia-induced miRNAs in primary colon TICs. Through stable overexpression of miR-215, followed by a set of functional in vitro and in vivo investigations, miR-215 was pinpointed as a negative feedback regulator, working against the TIC-promoting effects of hypoxia. Furthermore, we could single out LGR5, a bona fide marker of non-neoplastic intestinal stem cells, as a downstream target of hypoxia/miR-215 signaling. The strong tumor- and TIC-suppressor potential of miR-215 and the regulatory role of the hypoxia/miR-215/LGR5 axis may thus represent interesting points of attack for the development of innovative anti-CSC therapy approaches.

Trefoil factors peptide-3 is associated with residual invasive breast carcinoma following neoadjuvant chemotherapy

Background

Breast carcinoma is the commonest cancer among UAE population and the most common cancer among females. Examination of the 5′ promoter regions of trefoil factor 3 (TFF3) gene has identified putative estrogen and progesterone receptor–DNA binding domains as direct response elements to estrogen and progesterone that are linked to breast functions or steroid regulation. The study was designed to determine the role of TFF3 in breast cancer chemoresistance with the aim of establishing TFF3 expression as a biomarker for drug resistance.

Methods

In total, 133 cases of breast carcinoma treated with neo-adjuvant therapy were collected. Tissue samples from pre-neoadjuvant therapy as well as tissues from post-neo-adjuvant therapy of those cases were collected and stained with immunohistochemistry for TFF3, Bcl2, BAX, cleaved caspase-3, AKT-1, NF kappa B and Ki-67.

Results

There was increased expression of TFF3 in residual invasive carcinoma cells. There was a significant correlation between the expression of TFF3 in breast carcinoma cells and response to neoadjuvant chemotherapy (p = 0.0165). There was significant co-expression of TFF3 with AKT1 (p = 0.0365), BCl2 (p = 0.0152), and NF Kappa-B (p = 0.0243) in breast carcinoma cases with residual carcinoma following neoadjuvant therapy which support the role of TFF3 in chemoresistance.

Conclusion

The expression of TFF3 is significantly associated with residual breast carcinoma following neoadjuvant chemotherapy suggesting its expression is associated with increased resistance to chemotherapy. This is supported by its co-expression with antiapoptotic proteins; BCl2, AKT1 and NF Kappa-B in residual breast carcinoma cells and very low proliferating index and apoptotic bodies in residual tumors.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5316-y) contains supplementary material, which is available to authorized users.

Macrophages promote epithelial proliferation following infectious and non-infectious lung injury through a Trefoil factor 2-dependent mechanism

Coordinated efforts between macrophages and epithelia are considered essential for wound healing, but the macrophage-derived molecules responsible for repair are poorly defined. This work demonstrates that lung macrophages rely upon Trefoil factor 2 to promote epithelial proliferation following damage caused by sterile wounding, Nippostrongylus brasiliensis or Bleomycin sulfate. Unexpectedly, the presence of T, B, or ILC populations was not essential for macrophage-driven repair. Instead, conditional deletion of TFF2 in myeloid-restricted CD11c^Cre TFF2 ^flox mice exacerbated lung pathology and reduced the proliferative expansion of CD45^- EpCAM⁺ pro-SPC⁺ alveolar type 2 cells. TFF2 deficient macrophages had reduced expression of the Wnt genes Wnt4 and Wnt16 and reconstitution of hookworm-infected CD11c^Cre TFF2^flox mice with rWnt4 and rWnt16 restored the proliferative defect in lung epithelia post-injury. These data reveal a previously unrecognized mechanism wherein lung myeloid phagocytes utilize a TFF2/Wnt axis as a mechanism that drives epithelial proliferation following lung injury.

Expression of two non-mutated genetic elements is sufficient to stimulate oncogenic transformation of human mammary epithelial cells

Trefoil factor 3 (TFF3) expression is positively associated with advanced clinicopathological features of mammary carcinoma (MC). Herein, we provide evidence for a functional role of TFF3 in oncogenic transformation of immortalized, but otherwise normal human mammary epithelial cells (HMECs), namely, HMEC-hTERT, MCF10A, and MCF12A. Forced expression of TFF3 in immortalized-HMECs enhanced cell proliferation, cell survival, anchorage-independent growth, produced highly disorganised three-dimensional (3D) acinar structures and generated tumours in immunocompromised mice. Forced expression of TFF3 in immortalized-HMECs stimulated STAT3 activity that was required for TFF3-stimulated cell proliferation, survival, and anchorage-independent growth. TFF3 specifically utilised STAT3 activity to govern a transcriptional program, which was required for TFF3-stimulated oncogenic transformation of immortalized-HMECs, including transcriptional upregulation of CCND1 and BCL2. siRNA-mediated depletion or functional inhibition of STAT3 significantly inhibited the TFF3-stimulated transcription of CCND1 and BCL2 and oncogenicity in immortalized-HMECs. Furthermore, DOX-inducible expression of TFF3 in HMEC-hTERT cells also permitted anchorage-independent growth and produced disorganized acinar structures in 3D Matrigel culture. Removal of DOX-induced expression of TFF3 in HMEC-hTERT cells, previously grown with DOX, resulted in efficient normalisation of the disorganized acinar architecture and attenuated cell viability in Matrigel culture. Cumulatively, these findings suggest that TFF3 is a potent oncogene and its increased expression along with hTERT in HMECs is sufficient to produce oncogenic transformation.

Overexpression of TFF3 is involved in prostate carcinogenesis via blocking mitochondria-mediated apoptosis

The overexpression of trefoil factor family 3 (TFF3) is observed in a variety of cancers, including prostate cancer (PCa), and its potential role in carcinogenesis, such as activating the PI3K/AKT pathway, is suggested. However, its role and its related mechanisms in prostate tumorigenesis remain unknown. To elucidate the role of TFF3 overexpression in PCa, we silenced TFF3 in two PCa cell lines that overexpressed TFF3 and explored the molecular mechanism behind its antiapoptotic role. We also examined TFF3 expression in 108 Korean PCa specimens and 106 normal prostate tissues by immunohistochemistry (IHC) analysis. The mean TFF3 IHC score in the tumor tissues was significantly higher than that in the normal tissues (4.702 vs. 0.311, P = 2.52 × 10-24). TFF3-silenced cells showed suppressed tumor cell growth and migration. TFF3 silencing decreased BCL2 and increased BAX expression. The translocation of BAX to the mitochondria was also confirmed. After TFF3 silencing, the expression of the mitochondrial proapoptotic proteins, cytochrome C and Smac/DIABLO, was elevated, and these proteins were released from the mitochondria to the cytosol. Downstream mediators of mitochondrial apoptosis, including cleaved caspase-3, caspase-9, and PARP, were also elevated. Accordingly, the proportion of apoptotic cells was significantly higher among TFF3-silenced cells. There was no difference in extrinsic apoptosis-related molecules after TFF3 silencing. All the results support that TFF3 silencing induces the downstream signaling pathway of mitochondria-mediated apoptosis. This study provides a better understanding of the mechanism of prostate tumorigenesis, suggesting TFF3 as a potential biomarker and therapeutic target of PCa.

Trefoil factor 3 mediation of oncogenicity and chemoresistance in hepatocellular carcinoma is AKT-BCL-2 dependent

The efficacious treatment of hepatocellular carcinoma (HCC) remains a challenge, partially being attributed to intrinsic chemoresistance. Previous reports have observed increased TFF3 expression in HCC. Herein, we investigated the functional role of TFF3 in progression of HCC, and in both intrinsic and acquired chemoresistance. TFF3 expression was observed to be upregulated in HCC and associated with poor clinicopathological features and worse patient survival outcome. Functionally, forced expression of TFF3 in HCC cell lines increased cell proliferation, cell survival, anchorage-independent and 3D matrigel growth, cell invasion and migration, and in vivo tumor growth. In contrast, depleted expression of TFF3 decreased the oncogenicity of HCC cells as indicated by the above parameters. Furthermore, forced expression of TFF3 decreased doxorubicin sensitivity of HCC cells, which was attributed to increased doxorubicin efflux and cancer stem cell-like behavior of Hep3B cells. In contrast, depletion of TFF3 increased doxorubicin sensitivity and decreased cancer stem cell-like behavior of Hep3B cells. Correspondingly, TFF3 expression was markedly increased in Hep3B cells with acquired doxorubicin resistance, while the depletion of TFF3 resulted in re-sensitization of the Hep3B cells to doxorubicin. The increased doxorubicin efflux and enhanced cancer stem cell-like behavior of the doxorubicin-resistant Hep3B cells was observed to be dependent on TFF3 expression. In addition, we determined that TFF3-stimulated oncogenicity and chemoresistance in HCC cells was mediated by AKT-dependent expression of BCL-2. Hence, therapeutic inhibition of TFF3 should be considered to hinder HCC progression and overcome intrinsic and acquired chemoresistance in HCC.

Avian Influenza Virus Subtype H9N2 Affects Intestinal Microbiota, Barrier Structure Injury, and Inflammatory Intestinal Disease in the Chicken Ileum

Avian influenza virus subtype H9N2 (H9N2 AIV) has caused significant losses to the poultry industry due to the high mortality associated with secondary infections attributable to E. coli. This study tries to address the underlying secondary mechanisms after H9N2 AIV infection. Initially, nine day-old specific pathogen-free chickens were assigned to control (uninfected) and H9N2-infected groups, respectively. Using Illumina sequencing, histological examination, and quantitative real-time PCR, it was found that H9N2 AIV caused intestinal microbiota disorder, injury, and inflammatory damage to the intestinal mucosa. Notably, the genera Escherichia, especially E. coli, significantly increased (p < 0.01) at five days post-infection (dpi), while Lactobacillus, Enterococcus, and other probiotic organisms were significantly reduced (p < 0.01). Simultaneously, the mRNA expression of tight junction proteins (ZO-1, claudin 3, and occludin), TFF2, and Muc2 were significantly reduced (p < 0.01), indicating the destruction of the intestinal epithelial cell tight junctions and the damage of mucin layer construction. Moreover, the mRNA expression of proinflammatory cytokines IFN-γ, IL-22, IFN-α, and IL-17A in intestinal epithelial cells were significantly upregulated, resulting in the inflammatory response and intestinal injury. Our findings may provide a theoretical basis for observed gastroenteritis-like symptoms such as diarrhea and secondary E. coli infection following H9N2 AIV infection.

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.

Frontline defenders: goblet cell mediators dictate host-microbe interactions in the intestinal tract during health and disease

Goblet cells (GCs) are the predominant secretory epithelial cells lining the luminal surface of the mammalian gastrointestinal (GI) tract. Best known for their apical release of mucin 2 (Muc2), which is critical for the formation of the intestinal mucus barrier, GCs have often been overlooked for their active contributions to intestinal protection and host defense. In part, this oversight reflects the limited tools available to study their function but also because GCs have long been viewed as relatively passive players in promoting intestinal homeostasis and host defense. In light of recent studies, this perspective has shifted, as current evidence suggests that Muc2 as well as other GC mediators are actively released into the lumen to defend the host when the GI tract is challenged by noxious stimuli. The ability of GCs to sense and respond to danger signals, such as bacterial pathogens, has recently been linked to inflammasome signaling, potentially intrinsic to the GCs themselves. Moreover, further work suggests that GCs release Muc2, as well as other mediators, to modulate the composition of the gut microbiome, leading to both the expansion as well as the depletion of specific gut microbes. This review will focus on the mechanisms by which GCs actively defend the host from noxious stimuli, as well as describe advanced technologies and new approaches by which their responses can be addressed. Taken together, we will highlight current insights into this understudied, yet critical, aspect of intestinal mucosal protection and its role in promoting gut defense and homeostasis.

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.

Localization of trefoil factor family peptide 3 (TFF3) in epithelial tissues originating from the three germ layers of developing mouse embryo

Trefoil factor family (TFF) peptides are involved in the maintenance of epithelial integrity and epithelial restitution. Mature epithelial tissues originate from different embryonic germ layers. The objective of this research was to explore the presence and localization of TFF3 peptide in mouse embryonic epithelia and to examine if the occurrence of TFF3 peptide is germ layer-dependent. Mouse embryos (14-18 days old) were fixed in 4% paraformaldehyde and embedded in paraffin. Immunohistochemistry was performed with affinity purified rabbit anti-TFF3 antibody, goat anti-rabbit biotinylated secondary antibody and streptavidin-horseradish peroxidase, followed by 3,3'-diaminobenzidine. TFF3 peptide was present in the gastric and intestinal mucosa, respiratory mucosa in the upper and lower airways, pancreas, kidney tubules, epidermis, and oral cavity. The presence and localization of TFF3 peptide was associated with the embryonic stage and tissue differentiation. TFF3 peptide distribution specific to the germ layers was not observed. The role of TFF3 peptide in cell migration and differentiation, immune response, and apoptosis might be associated with specific embryonic epithelial cells. TFF3 peptide may also be considered as a marker for mucosal maturation.

Release of HER2 repression of trefoil factor 3 (TFF3) expression mediates trastuzumab resistance in HER2+/ER+ mammary carcinoma

HER2+/ER+ breast cancer, a subset of the luminal B subtype, makes up approximately 10% of all breast cancers. The bidirectional crosstalk between HER2 and estrogen receptor (ER) in HER2+/ER+ breast cancer contributes to resistance towards both anti-estrogens and HER2-targeted therapies. TFF3 promotes breast cancer progression and has been implicated in anti-estrogen resistance in breast cancer. Herein, we investigated the cross-regulation between HER2 and estrogen-responsive TFF3, and the role of TFF3 in mediating trastuzumab resistance in HER2+/ER+ breast cancer. TFF3 expression was decreased by HER2 activation, and increased by inhibition of HER2 with trastuzumab in HER2+/ER+ breast cancer cells, partially in an ERα-independent manner. In contrast, the forced expression of TFF3 activated the entire HER family of receptor tyrosine kinases (HER1-4). Hence, HER2 negatively regulates its own signalling through the transcriptional repression of TFF3, while trastuzumab inhibition of HER2 results in increased TFF3 expression to compensate for the loss of HER2 signalling. In HER2+/ER+ breast cancer cells with acquired trastuzumab resistance, TFF3 expression was markedly upregulated and associated with a corresponding decrease in HER signalling. siRNA mediated depletion or small molecule inhibition of TFF3 decreased the survival and growth advantage of the trastuzumab resistant cells without re-sensitization to trastuzumab. Furthermore, TFF3 inhibition abrogated the enhanced cancer stem cell-like behaviour in trastuzumab resistant HER2+/ER+ breast cancer cells. Collectively, TFF3 may function as a potential biomarker and therapeutic target in trastuzumab resistant HER2+/ER+ breast cancer.

Tumor Necrosis Factor α-Dependent Neutrophil Priming Prevents Intestinal Ischemia/Reperfusion-Induced Bacterial Translocation

BACKGROUND

Intestinal ischemia/reperfusion (I/R) causes barrier impairment and bacterial influx. Protection against I/R injury in sterile organs by hypoxic preconditioning (HPC) had been attributed to erythropoietic and angiogenic responses. Our previous study showed attenuation of intestinal I/R injury by HPC for 21 days in a neutrophil-dependent manner.

AIM

To investigate the underlying mechanisms of neutrophil priming by HPC, and explore whether adoptive transfer of primed neutrophils is sufficient to ameliorate intestinal I/R injury.

METHODS

Rats raised in normoxia (NM) and HPC for 3 or 7 days were subjected to sham operation or superior mesenteric artery occlusion for I/R challenge. Neutrophils isolated from rats raised in NM or HPC for 21 days were intravenously injected into naïve controls prior to I/R.

RESULTS

Similar to the protective effect of HPC-21d, I/R-induced mucosal damage was attenuated by HPC-7d but not by HPC-3d. Naïve rats reconstituted with neutrophils of HPC-21d rats showed increase in intestinal phagocytic infiltration and myeloperoxidase activity, and barrier protection against I/R insult. Elevated free radical production, and higher bactericidal and phagocytic activity were observed in HPC neutrophils compared to NM controls. Moreover, increased serum levels of tumor necrosis factor α (TNFα) and cytokine-induced neutrophil chemoattractant-1 (CINC-1) were seen in HPC rats. Naïve neutrophils incubated with HPC serum or recombinant TNFα, but not CINC-1, exhibited heightened respiratory burst and bactericidal activity. Lastly, neutrophil priming effect was abolished by neutralization of TNFα in HPC serum.

CONCLUSIONS

TNFα-primed neutrophils by HPC act as effectors cells for enhancing barrier integrity under gut ischemia.

Impact of Novel Sorghum Bran Diets on DSS-Induced Colitis

We have demonstrated that polyphenol-rich sorghum bran diets alter fecal microbiota; however, little is known regarding their effect on colon inflammation. Our aim was to characterize the effect of sorghum bran diets on intestinal homeostasis during dextran sodium sulfate (DSS)-induced colitis. Male Sprague-Dawley rats (N = 20/diet) were provided diets containing 6% fiber from cellulose, or Black (3-deoxyanthocyanins), Sumac (condensed tannins) or Hi Tannin Black (both) sorghum bran. Colitis was induced (N = 10/diet) with three separate 48-h exposures to 3% DSS, and feces were collected. On Day 82, animals were euthanized and the colon resected. Only discrete mucosal lesions, with no diarrhea or bloody stools, were observed in DSS rats. Only bran diets upregulated proliferation and Tff3, Tgfβ and short chain fatty acids (SCFA) transporter expression after a DSS challenge. DSS did not significantly affect fecal SCFA concentrations. Bran diets alone upregulated repair mechanisms and SCFA transporter expression, which suggests these polyphenol-rich sorghum brans may suppress some consequences of colitis.

Deciphering the pathophysiology of irritable bowel syndrome and functional gastrointestinal disorders-an alternative model for pathogenesis: cytokine controlled transepithelial multi-feedback loop

A working theoretical model for irritable bowel syndrome (IBS) and other functional gastrointestinal disorders (FGIDs) does not exist, hampered by the lack of any clear cut invention that address all symptom and signs of the disease. Reports of cessation of symptom and signs of both major types of IBS have been published using a non-systemic, topically active agent-high potency polymerized cross-linked sucralfate (HPPCLS). The unique clinical effect of this non-systemic agent restricted to the luminal surface of the gut provides opportunity to elaborate on an alternative working model for the pathogenesis of IBS and FGIDs. While the chemical determinants of HPPCLS and the mucosal lining contribute to the clinical effects, the sequence of events resides in the functional interplay among elements within the mucosa itself. The proposed model assumes that failure of a pre-existing genomic-controlled surveillance of the epithelium localized to the luminal surface triggers primary and secondary immune activation of inflammation intent on restoring epithelial homeostasis. Delayed restoration of homeostasis results in all the symptoms, signs and likely molecular events that characterize IBS and FGIDs.

Molecular pathways driving disease-specific alterations of intestinal epithelial cells

Due to the fact that chronic inflammation as well as tumorigenesis in the gut is crucially impacted by the fate of intestinal epithelial cells, our article provides a comprehensive overview of the composition, function, regulation and homeostasis of the gut epithelium. In particular, we focus on those aspects which were found to be altered in the context of inflammatory bowel diseases or colorectal cancer and also discuss potential molecular targets for a disease-specific therapeutic intervention.

TFF3-dependent resistance of human colorectal adenocarcinoma cells HT-29/B6 to apoptosis is mediated by miR-491-5p regulation of lncRNA PRINS

Tumour necrosis factor-α (TNF-α) is a double-edged cytokine associated with pathogenesis of inflammatory-related cancers being also able to induce cancer cell death. In the process of tumour development or metastasis, cancer cells can become resistant to TNF-α. In trefoil factor 3 (TFF3) overexpressing colorectal adenocarcinoma cells (HT-29/B6), we observed enhanced resistance against TNF-α/interferon gamma-induced apoptosis. TFF3 is a secreted small peptide that supports intestinal tissue repair but is also involved in intestinal tumour progression and scattering. We hypothesised that TFF3 rescues intestinal epithelial cancer cells from TNF-α-induced apoptosis by involving regulatory RNA networks. In silico-based expression analysis revealed TFF3-mediated regulation of selected microRNAs as well as long non-coding RNAs (lncRNAs), whereas miR-491-5p was identified to target the lncRNA ‘psoriasis susceptibility-related RNA gene induced by stress’ (PRINS). RNA interference-based gain- and loss-of-function experiments examined miR-491-PRINS axis to exert the TFF3-mediated phenotype. Chemical inhibition of selected pathways showed that phosphatidylinositol 3-kinase/AKT accounts for TFF3-mediated downregulation of miR-491-5p and accumulation of PRINS. Moreover, we showed that PRINS colocalises with PMAIP1 (NOXA) in nuclei of HT-29/B6 possessing inhibitory effects. Immunoprecipitation experiments proved molecular interaction of PMAIP1 with PRINS. Our study provides an insight into RNA regulatory networks that determine resistance of colorectal cancer cells to apoptosis.

Expression of trefoil factors and TWIST1 in colorectal cancer and their correlation with metastatic potential and prognosis

AIM

To detect the expression of trefoil factors (TFFs) and TWIST1 in colorectal cancer (CRC) and analyze their correlation with metastasis and survival.

METHODS

This study examined the expression of TFF1, TFF3 and TWIST1 in a total of 75 tumor samples, 47 matched normal samples (15 cm from the lesion margin), 30 metastatic lymph nodes, and 10 liver metastatic cancer samples from patients with CRC. The relationship was then analyzed between the protein expression and different clinical records. TFF1, TFF3, TWIST1,E-cadherin, vimentin and β-catenin mRNA and protein expression levels were measured in colon cancer cell lines with different metastatic potentials (HIEC, HT29, SW620, and LoVo cells), and the correlation of the expression levels with epithelial-mesenchymal transition (EMT) was discussed.

RESULTS

It was found that 66.7% (50/75), 78.7% (59/75) and 54.7% (41/75) of tumor tissue samples exhibited positive staining for TFF1, TFF3 and TWIST1 and so did 27.3% (13/47), 100% (47/47) and 17% (8/47) of adjacent normal colorectal tissues. Compared with adjacent normal tissues, significant differences were found in the expression of all three proteins in different cancerous tissues (P < 0.05). Higher expression of TFF3 and TWIST1 was significantly correlated with lymph node metastasis (P = 0.034, P = 0.000), advanced stage (P = 0.031, P = 0.003), and poorer survival (P = 0.042 for the TFF3 group, P = 0.003 for the TWIST1 group). The expression of TFF3 and TWIST1 in cancer cell lines was higher than that in HIEC (a normal human intestinal epithelial cell line)(P < 0.05), and the expression intensity demonstrated a tendency to rise with increased metastatic potential both at the protein and mRNA levels. However, TFF1 expression demonstrated the opposite tendency. It was also observed that the expression of E-cadherin and β-catenin tended to decrease while that of vimentin, TWIST1 and Snail tended to rise with the increase in metastatic potential.

CONCLUSION

The expression of TFF3 and TWIST1 might be associated with the survival of patients with CRC after curative resection and might be pivotal predictors of disease progression. TFF3 may be correlated to the invasiveness of CRC.