Umbilical cord mesenchymal stem cell exosomes alleviate necrotizing enterocolitis in neonatal mice by regulating intestinal epithelial cells autophagy

BACKGROUND Necrotizing enterocolitis(NEC)is a severe gastrointestinal disease that affects premature infants.Although mounting evidence supports the therapeutic effect of exosomes on NEC,the underlying mechanisms remain unclear.AIM To investigate the mechanisms underlying the regulation of inflammatory response and intestinal barrier function by umbilical cord mesenchymal stem cell(UCMSCs)exosomes,as well as their potential in alleviating NEC in neonatal mice.METHODS NEC was induced in 5-d-old C57BL/6 pups through hypoxia and gavage feeding of formula containing lipopolysaccharide(LPS),after which the mice received human UCMSC exosomes(hUCMSC-exos).The control mice were allowed to breastfeed with their dams.Ileal tissues were collected from the mice and analyzed by histopathology and immunoblotting.Colon tissues were collected from NEC neonates and analyzed by immunofluorescence.Molecular biology and cell culture approaches were employed to study the related mechanisms in intestinal epithelial cells.RESULTS We found that autophagy is overactivated in intestinal epithelial cells during NEC,resulting in reduced expression of tight junction proteins and an increased inflammatory response.The ability of hUCMSC-exos to ameliorate NEC in a mouse model was dependent on decreased intestinal autophagy.We also showed that hUCMSC-exos alleviate the inflammatory response and increase migration ability in intestinal epithelial cells induced by LPS.CONCLUSION These results contribute to a better understanding of the protective mechanisms of hUCMSC-exos against NEC and provide a new theoretical and experimental foundation for NEC treatment.These findings also enhance our understanding of the role of the autophagy mechanism in NEC,offering potential avenues for identifying new therapeutic targets.

Tanshinone IIA protects intestinal epithelial cells from ferroptosis through the upregulation of GPX4 and SLC7A11

Background:Inflammatory bowel disease(IBD)is a chronic inflammatory disease of the gastrointestinal tract.The destruction of the intestinal epithelial barrier is one of the major pathological processes in IBD pathology.Growing evidence indicated that epithelial cell ferroptosis is linked to IBD and is considered a target process.Methods:RAS-selective lethal 3(RSL3)was used to induce ferroptosis in intestinal epithelial cell line No.6(IEC-6)cells,and cell ferroptosis and the effects of tanshinone IIA(Tan IIA)were determined by cell counting kit-8(CCK-8),reactive oxygen species(ROS)staining,Giemsa staining and transmission electron microscope(TEM).The cell viability of natural product library compounds was determined by CCK-8.The expression of ferroptosis-related genes were detected by real-time quantitative polymerase chain reaction(RT-qPCR)and western blot.Results:Treatment of IEC-6 cells results in the accumulation of ROS and typical morphological characteristics of ferroptosis.RSL3 treatment caused rapid cellular cytotoxicity which could be reversed by ferrostatin-1(Fer-1)in IEC-6 cells.Natural product library screening revealed that Tan IIA is a potent inhibitor of IEC-6 cell ferroptosis.Tan IIA could significantly protect the RSL3-induced ferroptosis of IEC-6 cells.Furthermore,the ferroptosis suppressors,glutathione peroxidase 4(GPX4),solute carrier family 7 member 11(SLC7A11),and miR-17-92 were found to be early response genes in RSL3-treated cells.Treatment of IEC-6 cells with Tan IIA resulted in upregulation of GPX4,SLC7A11,and miR-17-92.Conclusion:Our study demonstrated that Tan IIA protects IEC-6 cells from ferroptosis through the upregulation of GPX4,SLC7A11,and miR-17-92.The findings might provide a theoretical grounding for the future application of Tan IIA to treat or prevent IBD.

In vitro and in vivo evaluation of effects of Mg-6Zn alloy on tight junction of intestinal epithelial cell

The effects of biodegradable Mg?6Zn alloy on tight junction of intestinal epithelial cells (IEC-6) were investigated. In the in vitro experiments, the cells were exposed to Mg?6Zn alloy extracts with different concentrations (0, 20% and 40%) for 1, 3 and 5 d. The real-time polymerase chain reaction (PCR) results show that when the cells are treated with 40% and 20% extracts, the expression of Zona Occludens 1 (ZO-1) and Occludin increase as compared with those in the control group. In the in vivo experiments, Mg?6Zn alloy and titanium staples were implanted into rabbits’ intestinal tract for 1, 2 and 3 weeks. By immunohistochemical staining of peri-implant intestinal tissue, increased expression of Occludin and ZO-1 are observed in the Mg?6Zn alloy groups as compared with those in the titanium and control groups. The results show that Mg?6Zn alloy in intestine may promote the regeneration of tight junction, and the extract with a certain concentration can induce the expression of tight junction related genes in IEC-6 cells.

Intestinal epithelial cells in inflammatory bowel diseases

The pathogenesis of inflammatory bowel diseases (IBDs) seems to involve a primary defect in one or more of the elements responsible for the maintenance of intestinal homeostasis and oral tolerance. The most important element is represented by the intestinal barrier, a complex system formed mostly by intestinal epithelial cells (IECs). IECs have an active role in producing mucus and regulating its composition; they provide a physical barrier capable of controlling antigen traff ic through the intestinal mucosa. At the same time, they are able to play the role of non-professional antigen presenting cells, by processing and presenting antigens directly to the cells of the intestinal immune system. On the other hand, immune cells regulate epithelial growth and differentiation, producing a continuous bi-directional cross-talk within the barrier. Several alterations of the barrier function have been identif ied in IBD, starting from mucus features up to its components, from epithelial junctions up to the Toll-like receptors, and altered immune responses. It remains to be understood whether these defects are primary causes of epithelial damage or secondary effects. We review the possible role of the epithelial barrier and particularly describe the role of IECs in the pathogenesis of IBD.

Enteric glial cells and their role in the intestinal epithelial barrier

The intestinal epithelium constitutes a physical and functional barrier between the external environment and the host organism. It is formed by a continuous monolayer of intestinal epithelial cells maintained together by intercellular junctional complex, limiting access of pathogens, toxins and xenobiotics to host tissues. Once this barrier integrity is disrupted, inflammatory disorders and tissue injury are initiated and perpetuated. Beneath the intestinal epithelial cells lies a population of astrocyte-like cells that are known as enteric glia. The morphological characteristics and expression markers of these enteric glia cells were identical to the astrocytes of the central nervous system. In the past few years, enteric glia have been demonstrated to have a trophic and supporting relationship with intestinal epithelial cells. Enteric glia lesions and/or functional defects can be involved in the barrier dysfunction. Besides, factors secreted by enteric glia are important for the regulation of gut barrier function. Moreover, enteric glia have an important impact on epithelial cell transcriptome and induce a shift in epithelial cell phenotype towards increased cell adhesion and cell differentiation.Enteric glia can also preserve epithelial barrier against intestinal bacteria insult. In this review, we will describe the current body of evidence supporting functional roles of enteric glia on intestinal barrier.

Protective effects of Rheum tanguticum polysaccharide against hydrogen peroxide-induced intestinal epithelial cell injury

AIM: To describe the effect of Rheum tanguticum polysaccharide (RTP) on hydrogen peroxide-induced human intestinal epithelial cell injury. METHODS: Hydrogen peroxide (100 μmol/L) was introduced to induce human intestinal epithelial cell injury. Cells were pretreated with RTP (30,100,300 μg/mL) for 24 h before exposure to hydrogen peroxide. Cell viability was detected by MTT assay and morphological observation. Acridine orange staining and flow cytometry were performed to assess cell apoptosis. Lactate dehydrogenase (LDH) activity, production of malondialdehyde (MDA) and superoxide dismutase (SOD) activity were measured by spectrophotometry with corresponding assay kits. RESULTS: Following exposure to H2O2, a marked decrease in cell survival and SOD activity, increased production of MDA, LDH leakage and cell apoptosis were found. Pretreatment of the cells with RTP could significantly elevate cell survival, SOD activity and decrease the level of MDA, LDH activity and cell apoptosis. CONCLUSION: RTP may have cytoprotective and anti-oxidant effects against H2O2-induced intestinal epithelial cell injury by inhibiting cell apoptosis and necrosis. This might be one of the possible mechanisms of RTP for the treatment of ulcerative colitis in rats.

Wound healing of intestinal epithelial cells

The intestinal epithelial cells(IECs) form a selective permeability barrier separating luminal content from underlying tissues.Upon injury,the intestinal epithelium undergoes a wound healing process.Intestinal wound healing is dependent on the balance of three cellular events;restitution,proliferation,and differentiation of epithelial cells adjacent to the wounded area.Previous studies have shown that various regulatory peptides,including growth factors and cytokines,modulate intestinal epithelial wound healing.Recent studies have revealed that novel factors,which include toll-like receptors(TLRs),regulatory peptides,particular dietary factors,and some gastroprotective agents,also modulate intestinal epithelial wound repair.Among these factors,the activation of TLRs by commensal bacteria is suggested to play an essential role in the maintenance of gut homeostasis.Recent studies suggest that mutations and dysregulation of TLRs could be major contributing factors in the predisposition and perpetuation of inflammatory bowel disease.Additionally,studies have shown that specific signaling pathways are involved in IEC wound repair.In this review,we summarize the function of IECs,the process of intestinal epithelial wound healing,and the functions and mechanisms of the various factors that contribute to gut homeostasis and intestinal epithelial wound healing.

Probiotic modulation of dendritic cells co-cultured with intestinal epithelial cells

AIM： To investigate cytokine production and cell surface phenotypes of dendritic cells （DC） in the presence of epithelial cells stimulated by probiotics.METHODS： Mouse DC were cultured alone or together with mouse epithelial cell monolayers in normal or in- verted systems and were stimulated with heat-killed probiotic bacteria, Bifidobacterium lactis ADO 11 （BL）, Bifidobacterium bilfidum BGN4 （BB）, Lactobacillus casei IBS041 （LC）, and Lactobacillus acidophilus AD031 （LA）, for 12 h. Cytokine levels in the culture supernatants were determined by enzyme-linked immunosorbent as say and phenotypic analysis of DC was investigated by flow cytometry.RESULTS： BB and LC in singlecultured DC increased the expression of I-Ad, CD86 and CD40 （I-Ad, 18.51 vs 30.88, 46.11, CD86, 62.74 vs 92.7, 104.12; CD40, 0.67 vs 6.39, 3.37, P 〈 0.05）. All of the experimental probiot-ics increased the production of inflammatory cytokines, interleukin （IL）-6 and tumor necrosis factor （TNF）-α. However, in the normal coculture systems, LC and LA decreased the expression of I-A^α （39.46 vs 30.32, 33.26, P 〈 0.05）, and none of the experimental probiotics increased the levels of IL-6 or TNF-α. In the inverted coculture systems, LC decreased the expression of CD40 （1.36 vs -2.27, P 〈 0.05）, and all of the experimental probiotics decreased the levels of IL-6. In addition, BL increased the production of IL-10 （103.8 vs 166.0, P 〈 0.05） and LC and LA increased transforming growth factor-13 secretion （235.9 vs 618.9, 607.6, P 〈 0.05）.CONCLUSION： These results suggest that specific pro- biotic strains exert differential immune modulation mediated by the interaction of dendritic cells and epithelial cells in the homeostasis of gastrointestinal tract.

Qingyi decoction attenuates intestinal epithelial cell injury via the calcineurin/nuclear factor of activated T-cells pathway

BACKGROUND Recent studies have demonstrated that dysfunction of the intestinal barrier is a significant contributing factor to the development of severe acute pancreatitis(SAP).A stable intestinal mucosa barrier functions as a major anatomic and functional barrier,owing to the balance between intestinal epithelial cell(IEC)proliferation and apoptosis.There is some evidence that calcium overload may trigger IEC apoptosis and that calcineurin(CaN)/nuclear factor of activated Tcells(NFAT)signaling might play an important role in calcium-mediated apoptosis.AIM To investigate the potential mechanisms underlying the therapeutic effect of Qingyi decoction(QYD)in SAP.METHODS A rat model of SAP was created via retrograde infusion of sodium deoxycholate.Serum levels of amylase,tumor necrosis factor(TNF-α),interleukin(IL)-6,D-lactic acid,and diamine oxidase(DAO);histological changes;and apoptosis of IECs were examined in rats with or without QYD treatment.The expression of the two subunits of CaN and NFAT in intestinal tissue was measured via quantitative realtime polymerase chain reaction and western blotting.For in vitro studies,Caco-2 cells were treated with lipopolysaccharide(LPS)and QYD serum,and then cell viability and intracellular calcium levels were detected.RESULTS Retrograde infusion of sodium deoxycholate increased the severity of pancreatic and intestinal pathology and the levels of serum amylase,TNF-α,and IL-6.Both the indicators of intestinal mucosa damage(D-lactic acid and DAO)and the levels of IEC apoptosis were elevated in the SAP group.QYD treatment reduced the serum levels of amylase,TNF-α,IL-6,D-lactic acid,and DAO and attenuated the histological findings.IEC apoptosis associated with SAP was ameliorated under QYD treatment.In addition,the protein expression levels of the two subunits of CaN were remarkably elevated in the SAP group,and the NFATc3 gene was significantly upregulated at both the transcript and protein levels in the SAP group compared with the control group.QYD significantly restrained CaN and NFATc3 gene expression in the intestine,which was upregulated in the SAP group.Furthermore,QYD serum significantly decreased the LPS-induced elevation in intracellular free Ca^(2+)levels and inhibited cell death.CONCLUSION QYD can exert protective effects against intestinal mucosa damage caused by SAP and the protective effects are mediated,at least partially,by restraining IEC apoptosis via the CaN/NFATc3 pathway.

Effect of EPEC endotoxin and bifidobacteria on intestinal barrier function through modulation of toll-like receptor 2 and toll-like receptor 4 expression in intestinal epithelial cell-18

AIM To investigate toll-like receptor 2(TLR2) and TLR4 expression, following bifidobacteria and low-dose EPEC endotoxin treatment, and intestinal barrier function in rat intestinal epithelial cell-18(IEC-18).METHODS Six experimental groups were established-normal control, EPEC, Bifidobacteria infantis(B. infantis), B. longum, B. bifidum, and B. youth groups. Optimal EPEC endotoxin concentration, bifidobacteria fold dilution, and treatment duration were determined. Quantitative real-time polymerase chain reaction and western blot, respectively, were conducted to detect TLR2 and TLR4 m RNA and protein expression in IEC-18 cells. Transepithelial electrical resistance(TEER) was measured by the EVOM chopstick voltohmmeter in each group. All experiments were conducted in triplicate and data were analyzed on SPSS 16.RESULTS TLR2 and TLR4 m RNA and protein expression in the EPEC group were significantly higher than in the control group(P < 0.05). TLR2 m RNA and protein expression in the B. infantis, B. longum and B. youth groups were significantly lower than in the normal control group(P < 0.05). TLR4 m RNA and protein expression in the B. bifidum and B. youth groups were significantly lower than in normal controls(P < 0.05). In addition, the TEER in B. infantis, B. longum, B. bifidum, and B. youth groups were decreased by 19%, 18%, 23% and 23%, respectively, after 120 min of intervention, as compared to the control group. However, the TEER in the EPEC group was significantly decreased by 67% in comparison to the normal control group(P < 0.05).CONCLUSION Bifidobacteria protect IEC-18 cells against injury by down-regulating TLR2 and TLR4 expression and enhance intestinal barrier function to protect the intestinal epithelial cells from pathogenic invasion.

A Comparative Study on Rat Intestinal Epithelial Cells and Resident Gut Bacteria (ii) Effect of Arsenite

Objective In order to use facultative gut bacteria as an alternate to animals for the initial gastrointestinal toxicity screening of heavy metals, a comparative study on rat intestinal epithelial cells and resident gut bacteria was undertaken. Methods in vitro growth rate of four gut bacteria, dehydrogenase （DHA） and esterase （EA） activity test, intestinal epithelial and bacterial cell membrane enzymes and in situ effect of arsenite were analysed. Results Growth profile of mixed resident population of gut bacteria and pure isolates of Escherichia coli, Pseudomonas sp., Lactobacillus sp., and Staphylococcus sp. revealed an arsenite （2-20 ppm） concentration-dependent inhibition. The viability pattern of epithelial cells also showed similar changes. DHA and EA tests revealed significant inhibition （40%-72%） with arsenite exposure of 5 and 10 ppm in isolated gut bacteria and epithelial cells. Decrease in membrane alkaline phosphatase and Ca^2＋-Mg^2＋-ATPase activities was in the range of 33%-55% in four bacteria at the arsenite exposure of 10 ppm, whereas it was 60%-65% in intestinal epithelial villus cells, in situ incubation of arsenite using intestinal loops also showed more or less similar changes in membrane enzymes of resident gut bacterial population and epithelial cells. Conclusion The results indicate that facultative gut bacteria can be used as suitable in vitro model for the preliminary screening of arsenical gastrointestinal cytotoxic effects.

Adipose-derived mesenchymal stem cells alleviate TNBS-induced colitis in rats by influencing intestinal epithelial cell regeneration, Wnt signaling, and T cell immunity

BACKGROUND Conventional Crohn’s disease(CD)treatments are supportive rather than curative and have serious side effects.Adipose-derived mesenchymal stem cells(ADSCs)have been gradually applied to treat various diseases.The therapeutic effect and underlying mechanism of ADSCs on CD are still not clear.AIM To investigate the effect of ADSC administration on CD and explore the potential mechanisms.METHODS Wistar rats were administered with 2,4,6-trinitrobenzene sulfonic acid(TNBS)to establish a rat model of CD,followed by tail injections of green fluorescent protein(GFP)-modified ADSCs.Flow cytometry,qRT-PCR,and Western blot were used to detect changes in the Wnt signaling pathway,T cell subtypes,and their related cytokines.RESULTS The isolated cells showed the characteristics of ADSCs,including spindle-shaped morphology,high expression of CD29,CD44,and CD90,low expression of CD34 and CD45,and osteogenic/adipogenic ability.ADSC therapy markedly reduced disease activity index and ameliorated colitis severity in the TNBS-induced rat model of CD.Furthermore,serum anti-sacchromyces cerevisiae antibody and panti-neutrophil cytoplasmic antibody levels were significantly reduced in ADSCtreated rats.Mechanistically,the GFP-ADSCs were colocalized with intestinal epithelial cells(IECs)in the CD rat model.GFP-ADSC delivery significantly antagonized TNBS-induced increased canonical Wnt pathway expression,decreased noncanonical Wnt signaling pathway expression,and increased apoptosis rates and protein level of cleaved caspase-3 in rats.In addition,ADSCs attenuated TNBS-induced abnormal inflammatory cytokine production,disturbed T cell subtypes,and their related markers in rats.CONCLUSION Successfully isolated ADSCs show therapeutic effects in CD by regulating IEC proliferation,the Wnt signaling pathway,and T cell immunity.

Effect of Dachengqi Tang(大承气汤)Granule on Proliferation ofIntestinal Epithelial Cells in Rats with ExperimentalIntestinal Obstruction

Objective: To study the effects of Dachengqi Tang (DCQT) granule on the proliferation of the intestinal epithelial cells in rats with experimental intestinal obstruction. Methods: Experimental intestinal obstruction models were established in rats and autoradiography with 3 H-TdR was used to determine 3H-TdR labeling counts of intestinal epithelial cells in rats. Results: DCQT granule had no effects on 3H-TdR labeling counts of intestinal epithelial cells in normal rats. DCQT granule obviously increases the rate of renovation in intestinal epithelial cells of the intestinal obstruction rats. Conclusion: DCQT granule could reinforce the intestinal mucosa's defensive function by means of increasing the proliferation of intestinal epithelial cells.

In Vitro Evaluation of Effects of Mg-6Zn Alloy Extracts on Apoptosis of Intestinal Epithelial Cells

We assessed the in vitro cytotoxicity of Mg-6Zn alloy and analyzed the cell apoptosis rate and the expression of caspase-3 to evaluate the effects of Mg-6Zn alloy extracts on apoptosis of intestinal epithelial cells（IEC）-6. IEC-6 cells were cultured in different concentrations of Mg-6Zn alloy extracts（40%, 20%） and in the control group. The indirect effects of Mg-6Zn alloy on IEC-6 cells were studied by calculating the cell relative growth rate（RGR）, measuring the apoptosis of IEC-6 cells through flow cytometry, and investigating the expression of caspase-3 using real-time polymerase chain reaction. The experimental results show that the cytotoxicity of these extracts is Grade 0-1. The level of apoptosis in IEC-6 cells cultured in 40% Mg-6Zn alloy extracts is significantly higher than that in cells treated with 20% extract and the control group. The expression of caspase-3 is found to be up-regulated in the 40% extract as compared to 20% extract and the control group. Taken together, the data show that the Mg-6Zn alloy in 40% and 20% concentration extracts proves noncytotoxicity. But the 40% concentration of Mg-6Zn alloy extract can induce the apoptosis and the related caspase-3 expression in vitro.

Monomorphic epitheliotropic intestinal T-cell lymphoma with bone marrow involved: A case report

BACKGROUND Monomorphic epithelial intestinal T-cell lymphoma(MEITL)is a rare type of peripheral T-cell lymphoma.The clinical manifestations are diarrhea,abdominal pain,perforation and an abdominal mass.CASE SUMMARY We present a 52-year-old female patient who was diagnosed with MEITL.Further disease progression was observed after multiline chemotherapy.Eventually,the patient died of a severe infection.CONCLUSION MEITL is a rare intestinal primary T-cell lymphoma with aggressive behavior,a high risk of severe life-threatening complications,and a poor prognosis.

Chang'an Ⅱ Decoction(肠安Ⅱ号方)-Containing Serum Ameliorates Tumor Necrosis Factor-α-Induced Intestinal Epithelial Barrier Dysfunction via MLCK-MLC Signaling Pathway in Rats

Objective To investigate the effect of Chang’an Ⅱ Decoction(肠安Ⅱ号方))-containing serum on intestinal epithelial barrier dysfunction in rats.Methods Tumor necrosis factor(TNF)-α-induced injury of Caco-2 monolayers were established as an inflammatory model of human intestinal epithelium.Caco-2 monolayers were treated with blank serum and Chang’an Ⅱ Decoction-containing serum that obtained from the rats which were treated with distilled water and Chang’an Ⅱ Decoction intragastrically at doses of 0.49,0.98,1.96 g/(kg·d)for 1 week,respectively.After preparation of containing serum,cells were divided into the normal group,the model group,the Chang’an Ⅱ-H,M,and L groups(treated with 30 ng/mL TNF-αand medium plus 10%high,middle-,and low-doses Chang’an Ⅱ serum,respectively).Epithelial barrier function was assessed by transepithelial electrical resistance(TER)and permeability of fluorescein isothiocyanate(FITC)-labeled dextran.Transmission electron microscopy was used to observe the ultrastructure of tight junctions(TJs).Immunofluorescence of zonula occludens-1(ZO-1),claudin-1 and nuclear transcription factor-kappa p65(NF-κBp65)were measured to determine the protein distribution.The mRNA expression of myosin light chain kinase(MLCK)was measured by real-time polymerase chain reaction.The expression levels of MLCK,myosin light chain(MLC)and p-MLC were determined by Western blot.Results Chang’an Ⅱ Decoction-containing serum significantly attenuated the TER and paracellular permeability induced by TNF-α.It alleviated TNF-α-induced morphological alterations in TJ proteins.The increases in MLCK mRNA and MLCK,MLC and p-MLC protein expressions induced by TNF-αwere significantly inhibited in the Chang’an Ⅱ-H group.Additionally,Chang’an Ⅱ Decoction significantly attenuated translocation of NF-κBp65 into the nucleus.Conclusion High-dose Chang’an Ⅱ-containing serum attenuates TNF-α-induced intestinal barrier dysfunction.The underlying mechanism may be involved in inhibiting the MLCK-MLC phosphorylation signaling pathway mediated by NF-κBp65.

Cinnamicaldehyde regulates the expression of tight junction proteins and amino acid transporters in intestinal porcine epithelial cells

Background： Cinnamicaldehyde（CA） is a key flavor compound in cinnamon essential oil possessing various bioactivities. Tight junction（TJ） proteins are vital for the maintenance of intestinal epithelial barrier function,transport, absorption and utilization of dietary amino acids and other nutrients. In this study, we tested the hypothesis that CA may regulate the expression of TJ proteins and amino acid transporters in intestinal porcine epithelial cells（IPEC-1） isolated from neonatal pigs.Results： Compared with the control, cells incubated with 25 μmol/L CA had increased transepithelial electrical resistance（TEER） and decreased paracellular intestinal permeability. The beneficial effect of CA on mucosal barrier function was associated with enhanced protein abundance for claudin-4, zonula occludens（ZO）-1, ZO-2, and ZO-3. Immunofluorescence staining showed that 25 μmol/L CA promoted the localization of claudin-1 and claudin-3 to the plasma membrane without affecting the localization of other TJ proteins, including claudin-4, occludin,ZO-1, ZO-2, and ZO-3, compared with the control cells. Moreover, protein abundances for rBAT, xCT and LAT2 in IPEC-1 cells were enhanced by 25 μmol/L CA, while that for EAAT3 was not affected.Conclusions： CA improves intestinal mucosal barrier function by regulating the distribution of claudin-1 and claudin-3 in enterocytes, as well as enhancing protein abundance for amino acid transporters rBAT, xCT and LAT2 in enterocytes. Supplementation with CA may provide an effective nutritional strategy to improve intestinal integrity and amino acid transport and absorption in piglets.

Phytoglycoprotein isolated from Dioscorea batatas Decne promotes intestinal epithelial wound healing

Dioscorea batatas Decne(DBD)has been used to heal various illnesses of the kidney and intestine as an herbal medicine in Asia.As a source of therapeutic agents,many glycoproteins have been isolated from mushrooms and plants,but the functional role of glycoprotein in intestinal epithelial wound healing has not been understood yet.In the present study,we investigated the wound healing potentials of the 30 kDa glycoprotein(DBD glycoprotein)isolated from DBD in human intestinal epithelial(INT-407)cells.We found that DBD glycoprotein(100μg·mL^-1)significantly increased the motility of INT-407 cells for 24 h by activating protein kinase C(PKC).DBD glycoprotein stimulated the activation of p38 mitogen-activated protein kinase(MAPK),which is responsible for the phosphorylation of NF-κB inhibitorα(IκBα).DBD glycoprotein increased the level of profilin-1(PFN1),α-actinin and F-actin expression via activation of transcription factor,nuclear factor-kappa B(NF-κB)during its promotion of cell migration.Experimental mouse colitis was induced by adding dextran sulfate sodium(DSS)to the drinking water at a concentration of 4%(W/V)for 7 days.We figured out that administration of DBD glycoprotein(10 and 20 mg·kg-1)lowers the levels of disease activity index and histological inflammation in DSS-treated ICR mice.In this regard,we suggest that DBD glycoprotein has ability to promote the F-actin-related migration signaling events via activation of PKC and NF-κB in intestinal epithelial cells and prevent inflammatory bowel disease.

The developmental changes in intestinal epithelial cell proliferation,differentiation,and shedding in weaning piglets

Intestinal epithelial homeostasis plays an important role in intestinal morphology and function.However,the developmental changes in intestinal epithelial cell turnover in piglets during early weaning are unknown so far.Thus,the aim of this work was to detect changes in piglet gut development from weaning to post-weaning d 14.Accordingly,40 piglets were used in the present study,and 8 piglets were randomly selected for sampling at d 0,1,3,7 and 14 post-weaning,respectively.The results showed that weaning stress significantly affected small intestinal morphological architecture,and this impact was the worst on d 3,and then returned to normal on d 14.Furthermore,the number of the marker of proliferation Ki-67(Ki67)positive cells was decreased on d 1 and 3,and then recovered on d 14(P<0.001).Also,weaning strikingly increased jejunal epithelial cell shedding on d 1 to 7 compared on d 0(P<0.05).Moreover,weaning remarkably affected the number of small intestinal enterocytes,goblets and endocrine cells(P<0.05),and there were also significant differences in genes expression related to proliferation and differentiation(P<0.05).Additionally,the mechanistic target of rapamycin(mTOR)phosphorylation level was higher on d 3(P<0.05).However,the Wingless/Int1(WNT)/b-catenin pathway was not influenced by post-weaning days.Taken together,weaning induced noteworthy changes in intestinal epithelial cell proliferation,differentiation and shedding,and the mTOR signaling pathway was involved in this process.Our findings provide a cellular mechanism for intestinal developmental changes during weaning periods.This may provide nutritionists with better insight into designing efficient in-feed alternatives for preventing the unfavorable gut development in weaning piglets.

Lonicera caerulea polyphenols inhibit fat absorption by regulating Nrf2-ARE pathway mediated epithelial barrier dysfunction and special microbiota

Scope:High-fat diet(HFD)induces imbalance in the small intestine environment,where fat digestion and absorption mainly take place.This study aimed to elucidate the mechanisms by which Lonicera caerulea polyphenols(LCP)might inhibit fat absorption,from the perspective of small intestine microbiota and epithelial barrier integrity.Methods and results:Male Sprague-Dawley rats were given HFD with or without co-administration of LCP for 8 weeks.The results showed that LCP supplementation significantly decreased the levels of serum triglycerides(TG),total cholesterol(TC),and low-density lipoprotein cholesterol(LDL-C),and increased the contents of fecal sterols,in HFD rats.LCP also inhibited the dysfunction of the small intestine epithelial barrier,via alleviating the oxidative stress activated by Nrf2-ARE pathway,and by modulating the expressions of pro-inflammatory factors such as tumor necrosis factor-α(TNF-α),interleukin-6(IL-6),cyclooxygenase-2(COX-2),nuclear factor kappa-B p65(NF-κB p65)and inducible nitric oxide synthase(iNOS)in the small intestine.Additionally,LCP administration restored the balance in small intestine microbiota and increased the abundance of the specific bacteria,such as Lactobacillus,involved in fat absorption.Conclusion:Our results demonstrated that LCP may be beneficial to inhibit fat absorption.The mechanism seems to be associated with the protection of the epithelial barrier integrity and the modulation of specific bacteria in the small intestine.