Role of intestinal trefoil factor in protecting intestinal epithelial cells from burn-induced injury

Huangqin decoction alleviated irinotecan-induced diarrhea by inhibiting endoplasmic reticulum stress through activating AMPK/mTOR-mediated autophagy

ETHNOPHARMACOLOGICAL RELEVANCE

Huangqin decoction (HQD), a traditional Chinese antidiarrheal formula, is effective in treating chemotherapy-induced diarrhea (CID). However, its underlying mechanism has not been fully clarified.

AIM OF THE STUDY

This study aimed to determine whether the underlying mechanism of HQD against CID is related to the activation of AMPK/mTOR-mediated autophagy inhibiting endoplasmic reticulum (ER) stress.

MATERIALS AND METHODS

Network pharmacology was used to screen potential targets and pathways. The CID mouse model was induced by intraperitoneal injection of 75 mg/kg irinotecan consecutively for four days. The effectiveness of HQD against CID was evaluated through diarrhea score, intestinal epithelial permeability, etc. The histopathological changes of colon were evaluated by HE staining. Alcian blue and immunofluorescence staining were used to assess mucous layer and the expression of MUC2, TJP-1, Occludin, and LC3, relatively. The level of GRP78 and CHOP was assessed by RT-qPCR and WB. Furthermore, the levels of LC3II/I, Beclin-1, P62, AMPK, p-AMPK, mTOR, p-mTOR were evaluated by WB.

RESULTS

Network pharmacology highlighted that the therapeutic effects of HQD against CID may be related to ER stress, autophagy, AMPK, and mTOR signaling pathways, etc. Subsequently, we conducted animal experiments to validate the predicted results. HQD improved CID by attenuating diarrhea, intestinal permeability, etc. HQD could effectively repair intestinal mucous barrier by activating AMPK/mTOR-mediated autophagy to inhibit ER stress.

CONCLUSION

Irinotecan disrupted the intestinal barrier causing diarrhea, while HQD could repair intestinal barrier via inducing AMPK/mTOR-mediated autophagy inhibiting ER stress, thereby exerting therapeutic effects against CID.

Mechanism of nonylphenol induced gastric inflammation through NF-κB/NLRP3 signaling pathway

Studies have found that the intake of environmental endocrine disruptors was positively correlated with the occurrence of gastric diseases. The aim of this study was to determine whether nonylphenol (NP) exposure can induce gastric inflammation and whether its mechanism was related to NF-κB/NLRP3 signaling pathway. In vivo, male SD rats were randomly divided into 4 groups (12 rats/group): control group (corn oil), NP low (0.4mg/kg), medium (4mg/kg), and high (40mg/kg) dose groups. After 33 weeks of NP chronic exposure, it was found pathological changes in gastric tissues, increase the release of inflammatory factors, and effects expressions of genes related to the NF-κB/NLRP3 signaling pathway. In vitro, the GES-1 cell experiments, which included four groups: control (0 µmol/L NP), L (2.5 µmol/L NP), M (40 µmol/L NP), and H (60 µmol/L NP), confirmed that NP increased the release of inflammatory factors in the cells, and up-regulated the expression of proteins related to NF-κB/NLRP3 signaling pathway. Furthermore, when pyrrolidinedithiocarbamate ammonium (PDTC) blocked the NF-κB signaling pathway, it was found that the expression of related proteins in the NF-κB/NLRP3 signaling pathway was decreased, and the release of inflammatory factors in GES-1 cells caused by NP was also attenuated. The results of this study indicated that NP can induce inflammation in the stomach in vivo and in vitro, and its mechanism was related to the NF-κB/NLRP3 signaling pathway. These findings provided a new perspective on the mechanism of inflammatory response induced by exposure to environmental endocrine disruptors. Also, these findings indicated that therapeutic strategies for the NF-κB/NLRP3 signaling pathway may be new methods to treat inflammatory diseases.

Lactiplantibacillus plantarum Postbiotics: Alternative of Antibiotic Growth Promoter to Ameliorate Gut Health in Broiler Chickens

The postbiotic produced from Lactiplantibacillus plantarum has been revealed as a potential alternative to antibiotic growth promoters (AGP). It helps to stimulate growth performance, improve nutrient digestibility, intestinal histomorphology, immune response, and improve meat quality in livestock. However, there is a paucity of information on the effects of L. plantarum postbiotic produced by formulated media on the gut health and immune response. Therefore, this study was conducted by using three strains of dietary L. plantarum postbiotics to determine the growth performance, intestinal histomorphology, intestinal mucin production, and immune status in broiler chickens. A 245 male Cobb 500-day-old birds were assigned randomly to five treatments, namely, NC: basal diet only (negative control), OTC: basal diet + 0.01% (w/w) oxytetracycline (positive control), RG11: basal diet + 0.1% (v/w) Postbiotic RG11, RI11: basal diet + 0.1% (v/w) Postbiotic RI11, and RS5: basal diet + 0.1% (v/w) Postbiotic RS5. The body weight and feed intake were taken weekly. The small intestine and its mucus, ceca digesta were collected on days 21 and 42. Fresh excreta for crude mucin production were collected 3 days before slaughter on day 42. From the findings, RS5 recorded a significant highest (p < 0.05) final body weight, body weight gain, and significant lowest (p < 0.05) feed conversion ratio. The concentrations of glutathione peroxidase, superoxide dismutase (SOD), acidic mucin, sulfated mucin, and intestinal trefoil factor were significantly higher (p < 0.05) in the birds fed with RI11 and RS5. Postbiotics RI11 and RS5 had up-regulated expression of intestinal Mucin 2, occludin, and secretory immunoglobulin A. The antibiotic-fed chickens also showed a reduced (p < 0.05) total bacteria and Bifidobacterium population but a significantly increased (p < 0.05) the population of Escherichia coli in the jejunum. In conclusion, the supplementation of L. plantarum postbiotic can be used to substitute AGP as it promoted growth performance, mucin production, ameliorated tight junction permeability, and immune status in broiler chickens due to improved gut health and beneficial bacteria colonization.

FOXA1 transcription activates TFF1 to reduce 6‑OHDA‑induced dopaminergic neuron damage

Forkhead box A1 (FOXA1) plays an important role in the central nervous system, and its loss can lead to the downregulation of tyrosine hydroxylase, which directly affects the synthesis of dopamine, thus leading to Parkinson's disease (PD). The present study aimed to explore the specific role of FOXA1 in PD. Blood samples from patients with PD were collected to determine the expression levels of FOXA1 using reverse transcription-quantitative PCR (RT-qPCR). In addition, mouse dopaminergic neuron MES23.5 cells were induced with 6-hydroxydopamine (6-OHDA) to construct an in vitro PD model in order to study the effect of FOXA1 overexpression on cell inflammation, oxidative stress and apoptosis with RT-qPCR, assay kits and TUNEL assays, respectively. Subsequently, the expression of FOXA1 was silenced to assess the effect on the downstream mechanism. The results revealed that the expression level of FOXA1 was downregulated in patients with PD, and FOXA1 overexpression attenuated 6-OHDA-induced inflammation, oxidative stress and apoptosis in MES23.5 cells. Furthermore, FOXA1 could bind to the trefoil factor 1 (TFF1) promoter, and the effects of FOXA1 overexpression on cells were reversed by TFF1 silencing, indicating that TFF1 mediated the mechanism of FOXA1 overexpression in MES23.5 cells. In conclusion, following FOXA1 transcription, TFF1 expression was activated, thereby relieving 6-OHDA-induced cell inflammation, oxidative stress and apoptosis. The present findings suggested that FOXA1 may serve as a target for the treatment of PD.

Vaginal mucus in mice: developmental and gene expression features of epithelial mucous cells during pregnancy†

The vagina is the site of copulation and serves as the birth canal. It also provides protection against external pathogens. In mice, due to the absence of cervical glands, the vaginal epithelium is the main producer of vaginal mucus. The development and differentiation of vaginal epithelium-constituting cells and the molecular characteristics of vaginal mucus have not been thoroughly examined. Here, we characterized vaginal mucous cell development and the expression of mucus-related factors in pregnant mice. The vaginal mucous epithelium layer thickened and became multilayered after Day 12 of pregnancy and secreted increasing amounts of mucus until early postpartum. Using histochemistry and transmission electron microscopy, we found supra-basal mucous cells as probable candidates for precursor cells. In vaginal mucous cells, the expression of TFF1, a stabilizer of mucus, was high, and some members of mucins and antimicrobial peptides (MUC5B and DEFB1) were expressed in a stage-dependent manner. In summary, this study presents the partial characterization of vaginal epithelial mucous cell lineage and expression of genes encoding several peptide substances that may affect vaginal tissue homeostasis and mucosal immunity during pregnancy and parturition.

NF-kB-dependent activation of STAT3 by H. pylori is suppressed by TFF1

BACKGROUND

H. pylori infection is the main risk factor for gastric cancer. In this study, we investigated H. pylori-mediated activation of STAT3 and NF-κB in gastric cancer, using in vitro and in vivo models.

METHODS

To investigate the activation of NF-κB and STAT3 by H. pylori strains we used in vitro and in vivo mouse models, western blots, immunofluorescence, ChIP Assay, luciferase and quantitative real-time PCR assays.

RESULTS

Following infection with H. pylori in vitro, we found an earlier phosphorylation of NF-kB-p65 (S536), followed by STAT3 (Y705). Immunofluorescence, using in vitro and in vivo models, demonstrated nuclear localization of NF-kB and STAT3, following H. pylori infection. NF-kB and STAT3 luciferase reporter assays confirmed earlier activation of NF-kB followed by STAT3. In vitro and in vivo models demonstrated induction of mRNA expression of IL-6 (p < 0.001), VEGF-α (p < 0.05), IL-17 (p < 0.001), and IL-23 (p < 0.001). Using ChIP, we confirmed co-binding of both NF-kB-p65 and STAT3 on the IL6 promoter. The reconstitution of Trefoil Factor 1 (TFF1) suppressed activation of NF-kB with reduction in IL6 levels and STAT3 activity, in response to H. pylori infection. Using pharmacologic (BAY11-7082) and genetic (IκB super repressor (IκBSR)) inhibitors of NF-kB-p65, we confirmed the requirement of NF-kB-p65 for activation of STAT3, as measured by phosphorylation, transcription activity, and nuclear localization of STAT3 in in vitro and in vivo models.

CONCLUSION

Our findings suggest the presence of an early autocrine NF-kB-dependent activation of STAT3 in response to H. pylori infection. TFF1 acts as an anti-inflammatory guard against H. pylori-mediated activation of pro-inflammatory networks.

Effects of intestinal trefoil factor on intestinal mucus barrier in burned mice

Severe burns might cause intense inflammatory response and tissue ischemia and hypoxia, and these effects result in intestinal mucosal barrier damage. In this study, we evaluated the effects of recombinant human intestinal trefoil factor (rhITF) on the intestinal mucus barrier after burn injury. The results showed that rhITF could improve the intestinal mucosal damage index, decrease diamine oxidase (DAO) activity, reduce intestinal damage, and thereby alleviate intestinal mucous permeability. Severe burns were associated with subsequent decreases in the mucus thickness and the levels of hexose, and mucin, and rhITF administration might partially reverse these changes. Additional experiments showed that supplementation with rhITF markedly increased the mitochondrial respiratory control rate (RCR) and phosphorus-oxygen ratio (P/O) in intestinal tissue. Moreover, rhITF improved the intestinal mucosal blood flow (IMBF) and the levels of oxygen extraction (Oext), nitric oxide (NO) and ATP. These results suggest that ITF can improve the blood perfusion of the intestinal mucosa after severe burns, promote the transport of glutamine in the intestinal mucosa, improve the energy metabolism of goblet cells, stimulate goblet cell differentiation and maturation, promote the synthesis and secretion of intestinal mucus, and maintain the barrier function of intestinal mucus.

Effectiveness and mechanism study of glutamine on alleviating hypermetabolism in burned rats

OBJECTIVES

This study aimed to explore the effects of glutamine on hypermetabolic reactions in burned rats and its underlying mechanism.

METHODS

Fifty-five Sprague-Dawley rats were randomly divided into three groups, namely, the control (C), burned (B), and burned + glutamine (B + G) groups. Rats in the glutamine treatment group were supplemented with 1 g glutamine per kg body weight. Changes in body weight and resting energy expenditure in all groups were observed daily. Blood glucose and glucose tolerance level were measured on days 1, 3, 7, 10 and 14 after burn injury. On days 7 and 14 after injury, the rats were sacrificed, and the weight and protein content of the skeletal muscle were measured. Moreover, the level of glutamine, inflammatory mediator, nicotinamide adenine dinucleotide phosphate (NADPH), glutathione, and the activity of glutamine metabolic enzymes were measured.

RESULTS

The hypermetabolic reaction after burn injury was significantly inhibited by glutamine administration, and the range of variations in the resting energy expenditure and body weight indicators was narrowed remarkably (P < 0.05 or 0.01), whereas the weight and protein content of the skeletal muscle returned to normal (P < 0.05 or 0.01). Glutamine could increase glutaminase activity in various tissues, promote the utilization of glutamine, and appropriately reduce the degree of organ damage and inflammatory response (P < 0.05 or 0.01). Furthermore, glutamine could promote the synthesis of the reducing substances NADPH and glutathione (P < 0.05 or 0.01).

CONCLUSIONS

Glutamine administration effectively reduces hypermetabolic reactions by promoting NADPH synthesis, inhibiting oxidative stress, and improving glutamine utilization after burn injury.

Mechanistic study of PDIA1-catalyzed TFF3 dimerization during sepsis

AIMS

Trefoil factor 3 (TFF3) is a gut mucosal protective molecule that is secreted by intestinal goblet cells. The dimeric structure of TFF3 enables it to function in intestinal mucosal repair and to maintain its own stability. Protein disulfide isomerase a1 (PDIA1) can directly catalyze the formation, isomerization and reduction of disulfide bonds in proteins and may play an important role in the formation of TFF3 dimer. In this study, we focused on the specific molecular mechanism of TFF3 dimerization by PDIA1 and the changes during sepsis.

METHODS

We examined the changes of PDIA1 and TFF3 in sepsis rats and cell models and used a variety of experimental techniques to investigate the specific molecular mechanism of PDIA1-catalyzed TFF3 dimerization.

KEY FINDINGS

We found that PDIA1 can directly catalyze the dimerization of TFF3. Our MD model proposed that two TFF3 monomers form hydrogen bonds with the region b' of PDIA1 through two stepwise reactions. Furthermore, we propose that the Cys24-Cys27 active site at the region a' of PDIA1 mediates disulfide bond formation between the Cys79 residues of each of the two TFF3 monomers via deprotonation and nucleophilic attack. During sepsis, PDIA1 is downregulated and the excessive release of nitric oxide (NO) promoted PDIA1 nitrosylation. This modification reduced PDIA1 activity, which resulted in the corresponding decrease of TFF3 dimerization and compromised TFF3 dimer function.

SIGNIFICANCE

Our study revealed a novel mechanism for the inhibition of intestinal mucosal repair during sepsis and revealed novel targets for the prevention and treatment of sepsis.

Dynamic observation and analysis of metabolic response to moxibustion stimulation on ethanol-induced gastric mucosal lesions (GML) rats

Background

Gastric mucosal lesion (GML) is the initiating pathological process in many refractory gastric diseases. And moxibustion is an increasingly popular alternative therapy that prevents and treats diseases. However, there are few published reports about developing pathology of GML and therapeutic mechanism of moxibustion treatment on GML. In this study, we investigated pathology of GML and therapeutic mechanism of moxibustion treatment on GML.

Methods

The male Sprague-Dawley (SD) rats were induced by intragastric administration of 75% ethanol after fasting for 24 h and treated by moxibustion at Zusanli (ST36) and Liangmen (ST21) for 1 day, 4 days or 7 days. Then we applied ¹H NMR-based metabolomics to dynamic analysis of metabolic profiles in biological samples (stomach, cerebral cortex and medulla). And the conventional histopathological examinations as well as metabolic pathways assays were also performed.

Results

Moxibustion intervention showed a beneficial effect on GML by modulating comprehensive metabolic alterations caused by GML, including energy metabolism, membrane metabolism, cellular active and neurotransmitters function.

Conclusions

Moxibustion can effectively treat gastric mucosal damage and effectively regulate the concentration of some related differential metabolites to maintain the stability of the metabolic pathway.

Activation of STAT3 signaling is mediated by TFF1 silencing in gastric neoplasia

TFF1, a secreted protein, plays an essential role in keeping the integrity of gastric mucosa and its barrier function. Loss of TFF1 expression in the TFF1-knockout (KO) mouse leads to a pro-inflammatory phenotype with a cascade of gastric lesions that include low-grade dysplasia, high-grade dysplasia, and adenocarcinomas. In this study, we demonstrate nuclear localization of p-STAT^Y705, with significant overexpression of several STAT3 target genes in gastric glands from the TFF1-KO mice. We also show frequent loss of TFF1 with nuclear localization of STAT3 in human gastric cancers. The reconstitution of TFF1 protein in human gastric cancer cells and 3D gastric glands organoids from TFF1-KO mice abrogates IL6-induced nuclear p-STAT3^Y705 expression. Reconstitution of TFF1 inhibits IL6-induced STAT3 transcription activity, suppressing expression of its target genes. TFF1 blocks IL6Rα-GP130 complex formation through interfering with binding of IL6 to its receptor IL6Rα. These findings demonstrate a functional role of TFF1 in suppressing gastric tumorigenesis by impeding the IL6-STAT3 pro-inflammatory signaling axis.

Trefoil factor 1 (TFF1) is a protein secreted by the gastric mucosa that protects against gastric tumourigenesis. Here, the authors show that TFF1 inhibits the oncogenic inflammatory response and IL-6-mediated STAT3 activation by interfering with the binding of IL6 to its receptor IL6Rα.