BACKGROUND Colorectal cancer(CRC)is the third most common cancer worldwide and the second leading cause of cancer-related death.Over the past two decades,numerous researchers have provided important evidence regarding...BACKGROUND Colorectal cancer(CRC)is the third most common cancer worldwide and the second leading cause of cancer-related death.Over the past two decades,numerous researchers have provided important evidence regarding the role of tight junction(TJ)proteins in the occurrence and progression of CRC.The causal relationship between the presence of specific TJ proteins and the development of CRC has also been confirmed.Despite the large number of publications in this field,a bibliometric study to review the current state of research and highlight the research trends and hotspots in this field has not yet been performed.AIM To analyze research on TJs and CRC,summarize the field’s history and current status,and predict future research directions.METHODS We searched the Science Citation Index Expanded database for all literature on CRC and TJs from 2001-2023.We used bibliometrics to analyze the data of these papers,such as the authors,countries,institutions,and references.Co-authorship,co-citation,and co-occurrence analyses were the main methods of analysis.CiteSpace and VOSviewer were used to visualize the results.RESULTS A total of 205 studies were ultimately identified.The number of publications on this topic has steadily increased since 2007.China and the United States have made the largest contributions to this field.Anticancer Research was the most prolific journal,publishing 8 articles,while the journal Oncogene had the highest average citation rate(68.33).Professor Dhawan P was the most prolific and cited author in this field.Co-occurrence analysis of keywords revealed that“tight junction protein expression”,“colorectal cancer”,“intestinal microbiota”,and“inflammatory bowel disease”had the highest frequency of occurrence,revealing the research hotspots and trends in this field.CONCLUSION This bibliometric analysis evaluated the scope and trends of TJ proteins in CRC,providing valuable research perspectives and future directions for studying the connection between the two.It is recommended to focus on emerging research hotspots,such as the correlations among intestinal microbiota,inflammatory bowel disease,TJ protein expression,and CRC.展开更多
AIM: To investigate the effects of moxibustion on down-regulation of the colonic epithelial cell apoptosis and repair of the tight junctions in rats with Crohn's disease (CD). METHODS: Sixty male Sprague-Dawley ra...AIM: To investigate the effects of moxibustion on down-regulation of the colonic epithelial cell apoptosis and repair of the tight junctions in rats with Crohn's disease (CD). METHODS: Sixty male Sprague-Dawley rats were randomly divided into a normal control (NC) group, a model control (MC) group, an herbs-partitioned moxibustion (HPM) group, a mild-warm moxibustion (MWM) group and a salicylazosulphapyridine (SASP) group, with 12 rats in each group. The CD model rats were treated with trinitrobenzene sulphonic acid to induce intestinal inflammation. The rats in the HPM and MWM groups were treated at the Tianshu (ST25) and Qihai (CV6) acupoints once daily for 14 d, and the SASP group was fed SASP twice daily for 14 d. No additional treatment was given to the MC and NC groups. Themicrostructure of the colonic epithelium was observed under a transmission electron microscope, the transepithelial resistance was measured using a shortcircuit current, colonic epithelial cell apoptosis was determined by terminal deoxynucleotidyl transferasemediated dUTP-biotin nick end labelling assay, and the expression of occludin, claudin-1 and zonula occludens-l (ZO-1) in the colonic epithelial junction was determined by Western blotting and immunofluorescence staining. RESULTS: Compared with the MC group, the microstructure of the colonic epithelial barrier was signifi-cantly improved in rats treated with HPM, MWM or SASP, meanwhile, the current flow was reduced signifi-cantly, with values of 168.20 ± 6.14 vs 99.70 ± 3.13, 99.10 ± 4.28 and 120.30 ± 3.65 mA, respectively (P = 0.001). However, the HPM and MWM groups had higher current flow rates than the SASP group (99.70 ± 3.13, 99.10 ± 4.28 vs 120.30 ± 3.65 mA, P = 0.001). The number of the apoptotic colonic epithelial cells in HPM, MWM and SASP groups was largely reduced (61.5 ± 16.91 vs 15.5 ± 8.89, 14.8 ± 6.27 and 24.7 ± 9.68, respectively (P = 0.001); and the expression of occlu- din, claudin-1 and ZO-1 in the MWM and HPM groups was signifi cantly enhanced (0.48 ± 0.10, 0.64 ± 0.09 vs 0.18 ± 0.05 for occludin, 0.12 ± 0.02, 0.17 ± 0.03 vs 0.05 ± 0.01 for claudin-1, and 0.08 ± 0.01, 0.11 ± 0.01 vs 0.02 ± 0.01 for ZO-1). And in SASP group, the expression of occludin and ZO-1 was also signifi cantly increased (0.27 ± 0.04 vs 0.18 ± 0.05 for occludin and 0.05 ± 0.01 vs 0.02 ± 0.01 for ZO-1), but there was no significant difference for claudin-1. The HPM and MWM groups had higher expression of occludin, claudin-1 and ZO-1 than the SASP group. CONCLUSION: HPM and MWM treatment can down-regulate apoptosis of colonic epithelial cells, repair tight junctions and enhance colonic epithelial barrier function in rats with CD.展开更多
Background:Bacillus cereus is an important pathogen that causes human food poisoning,specifically diarrhea and vomiting.B.cereus can also induce mastitis in dairy cows and has a strong survival ability in milk,as it c...Background:Bacillus cereus is an important pathogen that causes human food poisoning,specifically diarrhea and vomiting.B.cereus can also induce mastitis in dairy cows and has a strong survival ability in milk,as it cannot be inactivated by high-temperature short-time pasteurization.Therefore,B.cereus can enter the market through pasteurized milk and other dairy products,imposing enormous hidden dangers on food safety and human health.Results:In this study,B.cereus 2101(BC)was isolated from milk samples of cows with mastitis.BC grew rapidly with strong hemolysis,making it difficult to prevent mastitis and ensure food security.MAC-T cells were treated with BC and/or Lactobacillus rhamnosus GR-1(LGR-1).Pretreatment with LGR-1 protected the integrity of tight junctions and the expression of zonula occludens-1(ZO-1)and occludin destroyed by BC.Furthermore,LGR-1 pretreatment reduced the expression of NOD-like receptor family member pyrin domain-containing protein 3(NLRP3),caspase recruitment and activation domain(ASC),Caspase-1 p20,gasdermin D(GSDMD)p30,inflammatory factors(interleukin(IL)-1βand IL-18),and cell death induced by BC.Moreover,LGR-1 pretreatment reduced NLRP3 inflammasome activity and increased expressions of ZO-1 and occludin induced by lipopolysaccharides(LPS)+ATP stimulation.MAC-T cells were transfected with NLRP3 si RNA or MCC950 and/or treated with BC and/or LGR-1.NLRP3-si RNA transfection and MCC950 attenuated BC-induced NLRP3 inflammasome activity.Expression of inflammatory cytokines and cell death suggested that the inflammatory pathway might play an important role in the induction of the NLRP3 inflammasome by BC and the protection of LGR-1.Conclusions:These results suggest that LGR-1 might be a probiotic alternative to antibiotics and could be administered to prevent mastitis in dairy cows,thus ensuring food security.展开更多
The tight junction (TJ) is a critical cellular component for maintenance of tissue integrity, cellular interactions and cell-cell communications, and physiologically functions as the "great wall" against ext...The tight junction (TJ) is a critical cellular component for maintenance of tissue integrity, cellular interactions and cell-cell communications, and physiologically functions as the "great wall" against external agents and the surrounding hostile environment. During the host-pathogen evolution, viruses somehow found the key to unlock the gate for their entry into cells and to exploit and exhaust the host cells. In the liver, an array of TJ molecules is localized along the bile canaliculi forming the blood-biliary barrier, where they play pivotal roles in paracellular permeability, bile secretion, and cell polarity. In pathology, certain hepatic TJ molecules mediate virus entry causing hepatitis infection; deregulation and functional abnormality of the TJ have also been implicated in triggering liver cancer development and metastasis. All these findings shed new insights on the understanding of hepatic TJs in the development of liver disease and provide new clues for potential intervention.展开更多
Pancreatic cancer continues to be a leading cause of cancer-related death worldwide and there is an urgent need to develop novel diagnostic and therapeutic strategies to reduce the mortality of patients with this dise...Pancreatic cancer continues to be a leading cause of cancer-related death worldwide and there is an urgent need to develop novel diagnostic and therapeutic strategies to reduce the mortality of patients with this disease. In pancreatic cancer, some tight junction proteins, including claudins, are abnormally regulated and therefore are promising molecular targets for diagnosis, prognosis and therapy. Claudin-4 and-18 are overexpressed in human pancreatic cancer and its precursor lesions. Claudin-4 is a high affinity receptor of Clostridium perfringens enterotoxin(CPE). The cytotoxic effects of CPE and monoclonal antibodies against claudin-4 are useful as novel therapeutic tools for pancreatic cancer. Claudin-18 could be a putative marker and therapeutic target with prognostic implications for patients with pancreatic cancer. Claudin-1,-7, tricellulin and marvelD3 are involved in epithelial to mesenchymal transition(EMT) of pancreatic cancer cells and thus might be useful as biomarkers during disease. Protein kinase C is closely related to EMT of pancreatic cancer and regulates tight junctions of normal human pancreatic duct epithelial cells and the cancer cells. This review focuses on the regulation of tight junctions via protein kinase C during EMT in human pancreatic cancer for the purpose of developing new diagnostic and therapeutic modalities for pancreatic cancer.展开更多
Objective:In this study,the influence of puerarin,paeoniflorin,and menthol on the structure and barrier function of tight junctions(TJs)in MadineDarby canine kidney epithelial(MDCK)and MDCK-multi-drug resistance 1(MDR...Objective:In this study,the influence of puerarin,paeoniflorin,and menthol on the structure and barrier function of tight junctions(TJs)in MadineDarby canine kidney epithelial(MDCK)and MDCK-multi-drug resistance 1(MDR1)cells was evaluated to determine the mechanisms by which the drugs cross the bloodebrain barrier(BBB).Method:Cells were treated with puerarin,paeoniflorin,and menthol followed by immunohistochemical staining with occludin,claudin-1,and F-actin.The cells were then observed using laser-scanning confocal microscopy.Average optical density(AOD)of the immunofluorescence images of the proteins were analyzed using ImageJ software while Transepithelial electrical resistance(TEER)was measured using an epithelial voltohmmeter.Results:Confocal microscopy revealed that puerarin-and paeoniflorin-treated tight junction proteins were conspicuous while menthol suppressed their expression.Correspondingly,AOD values of cells treated with puerarin or paeoniflorin,or both showed no difference compared to the control group(P>.05)while the menthol group value was downregulated.In 3 h,TEER of cells not treated with menthol were similar to the control group,while treatment with menthol significantly decreased TEER value(P<.05).In addition,application of menthol decreased TEER in MDCK cells earlier than in MDCK-MDR1 cells.Conclusion:Menthol but not puerarin and paeoniflorin may enhance paracellular transport and improve drug penetration of the BBB by disrupting the structure and,thereby,weakening the barrier function of TJs.展开更多
Imatinib has been widely used as a selective kinase inhibitor for treating a variety of cancers,and this molecule is very hydrophobic so it is usually modified with mesylate salt in clinic to increase bioavailability....Imatinib has been widely used as a selective kinase inhibitor for treating a variety of cancers,and this molecule is very hydrophobic so it is usually modified with mesylate salt in clinic to increase bioavailability.However,pH-dependent aqueous solubility and relatively high dosage of imatinib mesylate greatly reduce the clinical outcomes.To solve this problem,we developed an intestine enzyme-responsive hydrogel to efficiently encapsulate hydrophobic imatinib with long-term controlled release and enhanced intestinal permeability through oral administration.Methacrylic anhydride-modified carboxymethyl chitosan(MA-CMCS)was synthesized via amidation reaction and then MA-CMCS was crosslinked with photoinitator under UV-irradation to form a three-dimensional hydrophilic polymer network.The intestine enzyme responsiveness was endowed with imatinib-loaded hydrogel through hydrolyzation of glucosidic bond,which could achieve enzyme-triggered long-term drug release of up to 2 days.Furthermore,sodium deoxycholate was embedded into the hydrogel to synchronously open epithelial tight junctions with improved intestinal permeability.In vitro studies revealed similar lethality against colon cancer cell for both imatinib mesylate and imatinib-loaded hydrogels.Moreover,significantly enhanced in vivo tumor inhibition(6-fold higher compared to imatinib mesylate)was achieved after oral administration with imatinib-loaded hydrogels.Overall,this enzyme-responsive hydrogel could achieve long-term synchronous release of kinase inhibitor(imatinib)and tight junction permeation enhancer(sodium deoxycholate)at intestine with enhanced therapeutic efficiency,which could provide an effective approach to improve the bioavailability of hydrophobic anticancer chemodrugs with oral administration.展开更多
Tight junctions are mainly formed by two types of proteins;claudins and occludin, both of which are fundamental to maintain the integrity and barrier function of the intestinal epithelium. This barrier function allows...Tight junctions are mainly formed by two types of proteins;claudins and occludin, both of which are fundamental to maintain the integrity and barrier function of the intestinal epithelium. This barrier function allows for the absorption of nutrients, mainly by transcytosis;however, in birds, 90% of the substances are absorbed by paracellular mechanisms. Despite this, claudins present in th<span style="font-family:Verdana;"></span><span style="font-family:;" "="">e different parts of the intestinal tract of adult chickens are not known, much less their functional role. This study aimed to determine the presence of mRNA of claudins 1, 2, 3, 5, 10, 12, 16 and occludin, in the different regions of the intestine (duodenum, jejunum, ileum, cecum, and rectum) in chickens (<i>Gallus gallus domesticus</i>) through RT-PCR. To meet this goal, 7 weeks old roosters destined for slaughter and chicken embryos of 16 days of incubation (positive control) were used. For all the processed samples, amplicons of the expected size were obtained;claudin 1 (662 pb), claudin 2 (162 pb), claudin 3 (185 pb), claudin 5 (224 pb), claudin 10 (687 pb), claudin 12 (738 pb), claudin 16 (191 pb) and occludin (430 pb). To corroborate these findings, obtained amplicons were sequenced and, subsequently, a basic alignment was performed on the NCBI, obtaining a correlation of 100% with the original sequences in all analyzed samples. To our knowledge, the present work represents the first written report regarding the presence of mRNA of the main proteins involved in tight junction formation throughout the intestinal tract of domestic chickens of 7 weeks of age. These findings will allow elucidating the specific function of each of the reported proteins in the process of paracellular absorption in chickens.</span>展开更多
Background:Cells are influenced by their environment.In vivo,the corneal endothelium is subjected to intraocular pressure(IOP).The purpose of this project was to evaluate in vitro,the effect of the IOP on the formatio...Background:Cells are influenced by their environment.In vivo,the corneal endothelium is subjected to intraocular pressure(IOP).The purpose of this project was to evaluate in vitro,the effect of the IOP on the formation of tight junctions in the corneal endothelium.Methods:Cultivated corneal endothelial cells(P2-P3;n=6 populations)were seeded on devitalized on corneas(n=10 pairs).Native corneas and devitalized corneas were respectively used as positive(n=2 pairs)and negative controls(n=3 pairs).Corneas were placed in artificial anterior chambers and subjected to a hydrostatic pressure between 0.3 and 0.4 psi during 4-5 days.Unpressured control corneas were maintained in cell culture dishes.Pictures of the corneas were taken following the experiment to assess stromal transparency.Morphology,corneal thickness and distribution of ZO-1,n-cadherin,b-catenin,NaK ATPase pump and HCO3-cotransporter were evaluated by electron microscopy,histological staining and immunofluorescences.Results:Pressure treated corneas were more transparent than the controls.Thickness was accordingly reduced by 38.4%±4.9%for cultivated endothelium and 32.2%±2.7%for native endothelium.Negative controls change in transparency and thickness were marginal.Pressure treated cells showed none or at most marginal difference in morphology and expression of ZO-1,n-cadherin,b-catenin,NaK ATPase pump and HCO3-cotransporters and failed to recreate a phenotype similar to native corneas.Pressure however increased cortical localisation of the protein ZO-1 in both cultivated and native endothelium.Conclusions:These results suggest that anterior chamber hydrostatic pressure may enhance endothelial functionality by modulating the distribution of tight junction’s proteins.展开更多
Inflammatory bowel diseases are characterised by inflammation that compromises the integrity of the epithelial barrier. The intestinal epithelium is not only a static barrier but has evolved complex mechanisms to cont...Inflammatory bowel diseases are characterised by inflammation that compromises the integrity of the epithelial barrier. The intestinal epithelium is not only a static barrier but has evolved complex mechanisms to control and regulate bacterial interactions with the mucosal surface. Apical tight junction proteins are critical in the maintenance of epithelial barrier function and control of paracellular permeability. The characterisation of alterations in tight junction proteins as key players in epithelial barrier function in inflammatory bowel diseases is rapidly enhancing our understanding of critical mechanisms in disease pathogenesis as well as novel therapeutic opportunities. Here we give an overview of recent literature focusing on the role of tight junction proteins, in particular claudins, in inflammatory bowel diseases and inflammatory bowel disease associated colorectal cancer.展开更多
Triptolide(TP),an active component of Tripterygium wilfordii Hook.f.(TWHF),has been widely used for centuries as a traditional Chinese medicine.However,the clinical application of TP has been restricted due to multita...Triptolide(TP),an active component of Tripterygium wilfordii Hook.f.(TWHF),has been widely used for centuries as a traditional Chinese medicine.However,the clinical application of TP has been restricted due to multitarget toxicity,such as hepatotoxicity.In this study,28 days of oral TP administration(100,200,or 400μg·kg^(-1)·d^(-1))induced the occurrence of cholestasis in female Wistar rats,as evidenced by increased serum levels ofγ-glutamyl transpeptidase(γ-GGT),alkaline phosphatase(ALP)and hepatic total bile acids(TBAs).In addition,the heptocyte polarity associated with the strcture of tight junctions(TJs)was disrupted in both rats and sandwich-cultured primary hepatocytes.Immunoblotting revealed decreased expression of the TJ-associated proteins occludin,claudin^(-1),and zonula occludens protein(ZO^(-1)),and downregulated m RNA levels of these TJs was also detected by real-time PCR.An immunofluorescence analysis showed abnormal subcellular localization of occludin,claudin^(-1) and ZO^(-1),which was also confirmed by transmission electron microscopy.Moreover,the concentration of FITC-dextran,a marker of paracellular penetration,was found to increase rapidly in bile increased rapidly(within 6 minutes)after treatment with TP,which indicated the functional impairment of TJs.Taken together,these results suggest that the administration of TP for 28 consecutive days to rats could induce cholestatic injury in the liver,and the increased paracellular permeability might play an important role in these pathological changes.展开更多
Objective：To investigate the changes of intestinal mucosa tight junctions （TJs） claudin-1, -3, -4 proteins and mRNA changes in patients with irritable bowel syndrome （IBS） and to elucidate their possible roles in...Objective：To investigate the changes of intestinal mucosa tight junctions （TJs） claudin-1, -3, -4 proteins and mRNA changes in patients with irritable bowel syndrome （IBS） and to elucidate their possible roles in the changes of bowel evacuation habit and formation. Methods： Claudin-1, -3, -4 proteins and mRNA were evaluated in intestinal mucosa in control group, D-IBS （diarrhea IBS） group and C-IBS （constipation IBS） group with immunohistochemical assay and Realtime-PCR. Results： It was observed that claudin-1, -3, -4 proteins were localized in the membranes of epithelial cells along the entire length of the plasma membrane including the apical end of the epithelial cells. The elaudins were concentrated at the site of TJs only. Claudin-1, 3, -4 mRNA and claudin-1 protein in small intestinal mucosa and colonal mucous in D-IBS group were significantly downregulated （P〈0.05）. Claudin-1, -3, -4 mRNA and proteins in small intestinal mucosa and colonal mucous in C-IBS group were significantly upregulated （P〈0. 05）. There was no significant difference in the expression of claudin-3 protein in both small intestinal mueosa and colonal mucous between D-IBS group and control group（P〉0.05）. Similarly, no significantly different expression of claudin-4 protein in colonal mucous in D-IBS group was found compared with control group （P〉0.05）. Otherwise, the expression of claudin 4 protein in small intestinal mucosa decreased in D-IBS group （P〈0.05）. Conclusion： Claudin-1, -3, -4 may play a potential important role in the changes of bowel evacuation habit and formation in patients with IBS. It is not due to the localization changes of claudin proteins in TJ, but may be caused by the quantitative changes of the expression of TJ proteins and mRNA.展开更多
The blood-brain barrier(BBB)is a barrier system separating the central nervous system from blood circulation.Connections between cells within the BBB involve specialized endothelial tight junction(TJ)proteins.BBB dama...The blood-brain barrier(BBB)is a barrier system separating the central nervous system from blood circulation.Connections between cells within the BBB involve specialized endothelial tight junction(TJ)proteins.BBB damage is strongly associated with numerous pathological changes in epilepsy.Endothelial cells and their TJs play a pivotal role in maintaining the BBB integrity.Astrocytes cannot directly contact endothelial cells,but the glymphatic system represents a new model to explain their relationship in epilepsy development.Leakage of albumin caused by BBB damage is a pivotal factor leading to the disruption of gap junction(GJ)function and structural abnormalities in astrocytes.Exposure to albumin from the circulation is one of the key factors in comprehending the subsequent proepileptic alterations in astrocytes resulting from BBB disruption.This review summarizes the association between the disruption of the BBB and the activation of astrocytes in epilepsy via alternation of GJs.In addition,the imaging assessment methods used for BBB damage are discussed.展开更多
Tricellulin,a key tricellular tight junction(TJ)protein,is essential for maintaining the barrier integrity of acinar epithelia against macromolecular passage in salivary glands.This study aims to explore the role and ...Tricellulin,a key tricellular tight junction(TJ)protein,is essential for maintaining the barrier integrity of acinar epithelia against macromolecular passage in salivary glands.This study aims to explore the role and regulatory mechanism of tricellulin in the development of salivary gland hypofunction in Sjögren’s syndrome(SS).Employing a multifaceted approach involving patient biopsies,non-obese diabetic(NOD)mice as a SS model,salivary gland acinar cell-specific tricellulin conditional knockout(TricCKO)mice,and IFN-γ-stimulated salivary gland epithelial cells,we investigated the role of tricellulin in SS-related hyposalivation.Our data revealed diminished levels of tricellulin in salivary glands of SS patients.Similarly,NOD mice displayed a reduction in tricellulin expression from the onset of the disease,concomitant with hyposecretion and an increase in salivary albumin content.Consistent with these findings,TricCKO mice exhibited both hyposecretion and leakage of macromolecular tracers when compared to control animals.Mechanistically,the JAK/STAT1/miR-145 axis was identified as mediating the IFN-γ-induced downregulation of tricellulin.Treatment with AT1001,a TJ sealer,ameliorated epithelial barrier dysfunction,restored tricellulin expression,and consequently alleviated hyposalivation in NOD mice.Importantly,treatment with miR-145 antagomir to specifically recover the expression of tricellulin in NOD mice significantly alleviated hyposalivation and macromolecular leakage.Collectively,we identified that tricellulin deficiency in salivary glands contributed to hyposalivation in SS.Our findings highlight tricellulin as a potential therapeutic target for hyposecretion,particularly in the context of reinforcing epithelial barrier function through preventing leakage of macromolecules in salivary glands.展开更多
Background The aim of this study was to determine whether and how Zn proteinate with moderate chelation strength(Zn-Prot M)can alleviate heat stress(HS)-induced intestinal barrier function damage of broilers.A complet...Background The aim of this study was to determine whether and how Zn proteinate with moderate chelation strength(Zn-Prot M)can alleviate heat stress(HS)-induced intestinal barrier function damage of broilers.A completely randomized design was used for comparatively testing the effects of Zn proteinate on HS and non-HS broilers.Under high temperature(HT),a 1(Control,HT-CON)+2(Zn source)×2(added Zn level)factorial arrangement of treatments was used.The 2 added Zn sources were Zn-Prot M and Zn sulfate(ZnS),and the 2 added Zn levels were 30 and 60 mg/kg.Under normal temperature(NT),a CON group(NT-CON)and pair-fed group(NT-PF)were included.Results The results showed that HS significantly reduced mRNA and protein expression levels of claudin-1,occludin,junctional adhesion molecule-A(JAMA),zonula occludens-1(ZO-1)and zinc finger protein A20(A20)in the jejunum,and HS also remarkably increased serum fluorescein isothiocyanate dextran(FITC-D),endotoxin and interleukin(IL)-1βcontents,serum diamine oxidase(DAO)and matrix metalloproteinase(MMP)-2 activities,nuclear factor kappa-B(NF-κB)p65 mRNA expression level,and protein expression levels of NF-κB p65 and MMP-2 in the jejunum.However,dietary supplementation with Zn,especially organic Zn as Zn-Prot M at 60 mg/kg,significantly decreased serum FITC-D,endotoxin and IL-1βcontents,serum DAO and MMP-2 activities,NF-κB p65 mRNA expression level,and protein expression levels of NF-κB p65 and MMP-2 in the jejunum of HS broilers,and notably promoted mRNA and protein expression levels of claudin-1,ZO-1 and A20.Conclusions Our results suggest that dietary Zn,especially 60 mg Zn/kg as Zn-Prot M,can alleviate HS-induced intestinal barrier function damage by promoting the expression of TJ proteins possibly via induction of A20-mediated suppression of the NF-κB p65/MMP-2 pathway in the jejunum of HS broilers.展开更多
Atopic dermatitis(AD)is a chronic inflammatory skin disease with xerosis,itchiness,as well as interconnection with immunoglobulin E(Ig E),mediated foods including airborne allergies.AD is not only related to the dimin...Atopic dermatitis(AD)is a chronic inflammatory skin disease with xerosis,itchiness,as well as interconnection with immunoglobulin E(Ig E),mediated foods including airborne allergies.AD is not only related to the diminished stratum corneum barrier but also presents with an unusual expression of tight junctions(TJs)proteins.TJ barrier dysfunction leads to impairment in the stratum corneum(SC)barrier.The significant role of TJs in the epidermal barrier as indicated by Claudin-1(Cldn-1)deficient mice that undergo high transepidermal water loss(TEWL)and skin dehydration.In atopic dermatitis,downregulation of Cldn-1 was observed due to inflammation.Still,a lack of distinct understanding exists in considering tight junction barrier impairment as a cause or outcome in atopic dermatitis.This review summarizes TJs main role in skin barrier function and TJ proteins(TJPs)expression observed in AD patients.展开更多
This study examined effects of dietary protein sources and levels on intestinal health of 21 to 35 d-old weaned piglets fed antibiotics-free diets. A total of 150 weaned piglets(21 d of age) were allotted to 5 dietary...This study examined effects of dietary protein sources and levels on intestinal health of 21 to 35 d-old weaned piglets fed antibiotics-free diets. A total of 150 weaned piglets(21 d of age) were allotted to 5 dietary treatment groups. Diets were formulated, based on corn-soybean meal, with different protein sources(fish meal and soy protein concentrate) to provide different dietary CP levels. Piglets within 5 dietary treatments were fed diets as follows, respectively: 1) control diet of 17% CP(control); 2) 19% CP diets formulated with more soy protein concentrate(SPC19); 3) fish meal(FM19); 4) 23.7% CP diets formulated with more soy protein concentrate(SPC23); 5) fish meal(FM23). The results showed that piglets from control group had higher ADG and lower incidence of diarrhea compared with those of other groups(P < 0.05). The incidence of diarrhea of piglets in FM19 group was lower than those from SPC23 group and FM23 group(P < 0.05). With the higher CP levels, villous height and villous height to crypt depth ratio of piglets in the duodenum and jejunum were decreased(P < 0.05), but crypt depth was increased(P < 0.05). Comparing control group and other groups, we found the expression of inflammatory cytokines interleukin-1β(IL-1β) and interferon-γ(IFN-γ) were increased(P < 0.05) in the jejunum and colon of piglets, as did cystic fibrosis transmembrane conductance regulators(CFTR) in the distal colon. The relative transcript abundance of Zonula occludens-1(ZO-1) in the jejunum, and occludin in the jejunum and ileum of piglets fed 23.7% CP diets were reduced compared with those fed control diet(P < 0.05). In conclusion, the 17% CP diet without in-feed antibiotics helped improve growth performance and relief of diarrhea of 21 to 35 d-old weaned piglets. Dietary CP level, rather than its source(either fish meal or soy protein concentrate), has more significant impacts on the growth performance and intestinal health of 21 to 35 d-old weaned piglets when fed antibiotics-free diets.展开更多
Objectives:This study aimed to investigate the effect of the widely used food emulsifier glycerin monostearate(GM)on testicular toxicity caused by the mixture of three commonly used phthalate esters(MPEs)in rats,and f...Objectives:This study aimed to investigate the effect of the widely used food emulsifier glycerin monostearate(GM)on testicular toxicity caused by the mixture of three commonly used phthalate esters(MPEs)in rats,and further to explore the underlying mechanism.Materials and Methods:Thirty male Sprague-Dawley rats were randomly divided into three groups.Rats were orally treated with 160 mg/kg/d MPEs in the MPEs group;coinstantaneously treated with 160 mg/kg/d MPEs and 200 mg/kg/d GM in the MPEs+GM group;and treated with the excipient in the control group.The intervention lasted for 5 weeks.Testis weight,epididymis weight,testicular histopathology,and serum testosterone were detected for testicular toxicity evaluation.The testicular ultrastructure,the tight junction proteins zonula occluden(ZO)-1,and claudin were measured for the mechanism exploration.Results:The body weight,epididymis,serum testosterone level,and anogenital distance in the MPEs+GM group were significantly decreased compared with control group(P<0.05);Testicular histopathological observation showed that shed spermatids were observed in the MPEs+GM group.Ultrastructural observation of testicular cells showed that the cristae number was decreased in some mitochondria in the MPEs group,whereas the cristae were fused and disappeared in most mitochondria in the MPEs+GM group.The tight junctions were broken in the MPEs+GM group;meanwhile,the expression of ZO-1 and claudin were altered in the MPEs+GM group(P<0.01).Conclusions:The results from this study indicated that GM aggravated MPEs'testicular toxicity,which might relate to the injured mitochondria and damaged tight junctions in testicular tissue.展开更多
This study aimed to investigate the dose-effect of iron on growth performance,antioxidant function.intestinal morphology,and mRNA expression of jejunal tight junction protein in 1-to21-d-old yellow-feathered broilers....This study aimed to investigate the dose-effect of iron on growth performance,antioxidant function.intestinal morphology,and mRNA expression of jejunal tight junction protein in 1-to21-d-old yellow-feathered broilers.A total of 7201-d-old yellow-feathered maleb roilers were allocated to 9 treatments with 8 replicate cages of 10 birds per cage.The dietary treatments were consisted of a basal diet(contained 79.6 mg Fe kg^(-1))supplemented with 0,20,40,60,80,160,320,640,and 1,280 mg Fe kg^(-1)in the form of FeSO_(4)·7H_(2)O.Compared with the birds in the control group,birds supplemented with 20mg Fe kg^(-1)had higher average daily gain(ADG)(P<0.0001).Adding 640 and 1,280 mg Fe kg^(-1)significantly decreased ADG(P<0.0001)and average daily feed intake(ADFI)(P<0.0001)compared with supplementation of 20mg Fe kg^(-1).Malondialdehyde(MDA)concentration in plasma and duodenum increased linearly(P<0.0001),but MDA concentration in liver and jejunum increased linearly(P<0.05)or quadratically(P<0.05)with increased dietary Fe concentration.The villus height(VH)in duodenum and jejunum,and the ratio of villus height to crypt depth(V/C)in duodenum decreased linearly(P?0.05)as dietary Feincreased.As dietary Fe increased,the jejunal relative mRNA abundance of claudin-1 decreased linearly(P=0.001),but the jejunal relative mRNA abundance of zona occludens-1(ZO-1)and occludin decreased linearly(P?0.05)or quadratically(P?0.05).Compared with the supplementation of 20 mg Fe kg^(-1),the supplementation of640 mg Fe kg^(-1)or higher increased(P?0.05)MDA concentrations in plasma,duodenum,and jejunum,decreased VH in the duodenum and jejunum,and the addition of 1,280 mg Fe kg^(-1)reduced(P?0.05)the jejunal tight junction protein(claudin-1,ZO-1,occludin)mRNA abundance.In summary,640 mg of supplemental Fe kg^(-1)or greater was associated with decreased growth performance,increased oxidative stress,disrupted intestinal morphology,and reduced mRNA expression of jejunal tight junction protein.展开更多
The brain’s blood microvessels restrict the exchange of substances between the blood and brain tissue through the blood-brain barrier (BBB). Methyl-glyoxal (MG), a byproduct of glucose metabolism, contributes to the ...The brain’s blood microvessels restrict the exchange of substances between the blood and brain tissue through the blood-brain barrier (BBB). Methyl-glyoxal (MG), a byproduct of glucose metabolism, contributes to the formation of advanced glycation end products (AGEs) and disrupts the BBB, which is associated with neurodegenerative diseases. L-Theanine (TA), an amino acid found in green tea with antioxidant properties, may protect the BBB. This study aimed to determine whether MG increases reactive oxygen species (ROS) and permeability by reducing tight junction proteins in human cerebral microvascular endothelial cells (hCMEC/d3), and whether TA pretreatment can counteract these effects. Our findings demonstrated that MG treatment led to increased BBB permeability, decreased transendothelial electrical resistance (TEER) values to 39% of control levels, reduced expression of Claudin-5 to 53% and Occludin to 69% of control levels, and elevated intracellular ROS levels. TA pretreatment restored barrier integrity, preserved tight junction protein expression, and decreased ROS accumulation to levels comparable to control levels. These findings suggest that TA effectively prevents MG-induced BBB dysfunction by reducing oxidative stress and maintaining tight junction proteins, showing promise as a protective agent for the BBB in conditions associated with elevated MG and AGEs.展开更多
基金Supported by the National Natural Science Foundation of China,No.82170525Beijing Shijitan Hospital Professionals Training Program,No.2023 LJRCDL.
文摘BACKGROUND Colorectal cancer(CRC)is the third most common cancer worldwide and the second leading cause of cancer-related death.Over the past two decades,numerous researchers have provided important evidence regarding the role of tight junction(TJ)proteins in the occurrence and progression of CRC.The causal relationship between the presence of specific TJ proteins and the development of CRC has also been confirmed.Despite the large number of publications in this field,a bibliometric study to review the current state of research and highlight the research trends and hotspots in this field has not yet been performed.AIM To analyze research on TJs and CRC,summarize the field’s history and current status,and predict future research directions.METHODS We searched the Science Citation Index Expanded database for all literature on CRC and TJs from 2001-2023.We used bibliometrics to analyze the data of these papers,such as the authors,countries,institutions,and references.Co-authorship,co-citation,and co-occurrence analyses were the main methods of analysis.CiteSpace and VOSviewer were used to visualize the results.RESULTS A total of 205 studies were ultimately identified.The number of publications on this topic has steadily increased since 2007.China and the United States have made the largest contributions to this field.Anticancer Research was the most prolific journal,publishing 8 articles,while the journal Oncogene had the highest average citation rate(68.33).Professor Dhawan P was the most prolific and cited author in this field.Co-occurrence analysis of keywords revealed that“tight junction protein expression”,“colorectal cancer”,“intestinal microbiota”,and“inflammatory bowel disease”had the highest frequency of occurrence,revealing the research hotspots and trends in this field.CONCLUSION This bibliometric analysis evaluated the scope and trends of TJ proteins in CRC,providing valuable research perspectives and future directions for studying the connection between the two.It is recommended to focus on emerging research hotspots,such as the correlations among intestinal microbiota,inflammatory bowel disease,TJ protein expression,and CRC.
基金Supported by National Natural Science Foundation of China,No. 30772831National Basic Research Program of China, 973program, No. 2009CB522900Shanghai Leading Discipline Project, No. S30304
文摘AIM: To investigate the effects of moxibustion on down-regulation of the colonic epithelial cell apoptosis and repair of the tight junctions in rats with Crohn's disease (CD). METHODS: Sixty male Sprague-Dawley rats were randomly divided into a normal control (NC) group, a model control (MC) group, an herbs-partitioned moxibustion (HPM) group, a mild-warm moxibustion (MWM) group and a salicylazosulphapyridine (SASP) group, with 12 rats in each group. The CD model rats were treated with trinitrobenzene sulphonic acid to induce intestinal inflammation. The rats in the HPM and MWM groups were treated at the Tianshu (ST25) and Qihai (CV6) acupoints once daily for 14 d, and the SASP group was fed SASP twice daily for 14 d. No additional treatment was given to the MC and NC groups. Themicrostructure of the colonic epithelium was observed under a transmission electron microscope, the transepithelial resistance was measured using a shortcircuit current, colonic epithelial cell apoptosis was determined by terminal deoxynucleotidyl transferasemediated dUTP-biotin nick end labelling assay, and the expression of occludin, claudin-1 and zonula occludens-l (ZO-1) in the colonic epithelial junction was determined by Western blotting and immunofluorescence staining. RESULTS: Compared with the MC group, the microstructure of the colonic epithelial barrier was signifi-cantly improved in rats treated with HPM, MWM or SASP, meanwhile, the current flow was reduced signifi-cantly, with values of 168.20 ± 6.14 vs 99.70 ± 3.13, 99.10 ± 4.28 and 120.30 ± 3.65 mA, respectively (P = 0.001). However, the HPM and MWM groups had higher current flow rates than the SASP group (99.70 ± 3.13, 99.10 ± 4.28 vs 120.30 ± 3.65 mA, P = 0.001). The number of the apoptotic colonic epithelial cells in HPM, MWM and SASP groups was largely reduced (61.5 ± 16.91 vs 15.5 ± 8.89, 14.8 ± 6.27 and 24.7 ± 9.68, respectively (P = 0.001); and the expression of occlu- din, claudin-1 and ZO-1 in the MWM and HPM groups was signifi cantly enhanced (0.48 ± 0.10, 0.64 ± 0.09 vs 0.18 ± 0.05 for occludin, 0.12 ± 0.02, 0.17 ± 0.03 vs 0.05 ± 0.01 for claudin-1, and 0.08 ± 0.01, 0.11 ± 0.01 vs 0.02 ± 0.01 for ZO-1). And in SASP group, the expression of occludin and ZO-1 was also signifi cantly increased (0.27 ± 0.04 vs 0.18 ± 0.05 for occludin and 0.05 ± 0.01 vs 0.02 ± 0.01 for ZO-1), but there was no significant difference for claudin-1. The HPM and MWM groups had higher expression of occludin, claudin-1 and ZO-1 than the SASP group. CONCLUSION: HPM and MWM treatment can down-regulate apoptosis of colonic epithelial cells, repair tight junctions and enhance colonic epithelial barrier function in rats with CD.
基金the following funds:the National Key R&D Program of China(Project No.2017YFD0502200)the National Natural Science Foundation of China(Project No.31960721)the National Natural Science Foundation of China(Project No.31873034)。
文摘Background:Bacillus cereus is an important pathogen that causes human food poisoning,specifically diarrhea and vomiting.B.cereus can also induce mastitis in dairy cows and has a strong survival ability in milk,as it cannot be inactivated by high-temperature short-time pasteurization.Therefore,B.cereus can enter the market through pasteurized milk and other dairy products,imposing enormous hidden dangers on food safety and human health.Results:In this study,B.cereus 2101(BC)was isolated from milk samples of cows with mastitis.BC grew rapidly with strong hemolysis,making it difficult to prevent mastitis and ensure food security.MAC-T cells were treated with BC and/or Lactobacillus rhamnosus GR-1(LGR-1).Pretreatment with LGR-1 protected the integrity of tight junctions and the expression of zonula occludens-1(ZO-1)and occludin destroyed by BC.Furthermore,LGR-1 pretreatment reduced the expression of NOD-like receptor family member pyrin domain-containing protein 3(NLRP3),caspase recruitment and activation domain(ASC),Caspase-1 p20,gasdermin D(GSDMD)p30,inflammatory factors(interleukin(IL)-1βand IL-18),and cell death induced by BC.Moreover,LGR-1 pretreatment reduced NLRP3 inflammasome activity and increased expressions of ZO-1 and occludin induced by lipopolysaccharides(LPS)+ATP stimulation.MAC-T cells were transfected with NLRP3 si RNA or MCC950 and/or treated with BC and/or LGR-1.NLRP3-si RNA transfection and MCC950 attenuated BC-induced NLRP3 inflammasome activity.Expression of inflammatory cytokines and cell death suggested that the inflammatory pathway might play an important role in the induction of the NLRP3 inflammasome by BC and the protection of LGR-1.Conclusions:These results suggest that LGR-1 might be a probiotic alternative to antibiotics and could be administered to prevent mastitis in dairy cows,thus ensuring food security.
基金Supported by A GRF Grant from the Research Grants Council of Hong Kong to Luk JM,No.771607M
文摘The tight junction (TJ) is a critical cellular component for maintenance of tissue integrity, cellular interactions and cell-cell communications, and physiologically functions as the "great wall" against external agents and the surrounding hostile environment. During the host-pathogen evolution, viruses somehow found the key to unlock the gate for their entry into cells and to exploit and exhaust the host cells. In the liver, an array of TJ molecules is localized along the bile canaliculi forming the blood-biliary barrier, where they play pivotal roles in paracellular permeability, bile secretion, and cell polarity. In pathology, certain hepatic TJ molecules mediate virus entry causing hepatitis infection; deregulation and functional abnormality of the TJ have also been implicated in triggering liver cancer development and metastasis. All these findings shed new insights on the understanding of hepatic TJs in the development of liver disease and provide new clues for potential intervention.
基金Supported by Ministry of Education,Culture,Sports Science,and Technology,and the Ministry of Health,Labour and Welfare of Japan
文摘Pancreatic cancer continues to be a leading cause of cancer-related death worldwide and there is an urgent need to develop novel diagnostic and therapeutic strategies to reduce the mortality of patients with this disease. In pancreatic cancer, some tight junction proteins, including claudins, are abnormally regulated and therefore are promising molecular targets for diagnosis, prognosis and therapy. Claudin-4 and-18 are overexpressed in human pancreatic cancer and its precursor lesions. Claudin-4 is a high affinity receptor of Clostridium perfringens enterotoxin(CPE). The cytotoxic effects of CPE and monoclonal antibodies against claudin-4 are useful as novel therapeutic tools for pancreatic cancer. Claudin-18 could be a putative marker and therapeutic target with prognostic implications for patients with pancreatic cancer. Claudin-1,-7, tricellulin and marvelD3 are involved in epithelial to mesenchymal transition(EMT) of pancreatic cancer cells and thus might be useful as biomarkers during disease. Protein kinase C is closely related to EMT of pancreatic cancer and regulates tight junctions of normal human pancreatic duct epithelial cells and the cancer cells. This review focuses on the regulation of tight junctions via protein kinase C during EMT in human pancreatic cancer for the purpose of developing new diagnostic and therapeutic modalities for pancreatic cancer.
文摘Objective:In this study,the influence of puerarin,paeoniflorin,and menthol on the structure and barrier function of tight junctions(TJs)in MadineDarby canine kidney epithelial(MDCK)and MDCK-multi-drug resistance 1(MDR1)cells was evaluated to determine the mechanisms by which the drugs cross the bloodebrain barrier(BBB).Method:Cells were treated with puerarin,paeoniflorin,and menthol followed by immunohistochemical staining with occludin,claudin-1,and F-actin.The cells were then observed using laser-scanning confocal microscopy.Average optical density(AOD)of the immunofluorescence images of the proteins were analyzed using ImageJ software while Transepithelial electrical resistance(TEER)was measured using an epithelial voltohmmeter.Results:Confocal microscopy revealed that puerarin-and paeoniflorin-treated tight junction proteins were conspicuous while menthol suppressed their expression.Correspondingly,AOD values of cells treated with puerarin or paeoniflorin,or both showed no difference compared to the control group(P>.05)while the menthol group value was downregulated.In 3 h,TEER of cells not treated with menthol were similar to the control group,while treatment with menthol significantly decreased TEER value(P<.05).In addition,application of menthol decreased TEER in MDCK cells earlier than in MDCK-MDR1 cells.Conclusion:Menthol but not puerarin and paeoniflorin may enhance paracellular transport and improve drug penetration of the BBB by disrupting the structure and,thereby,weakening the barrier function of TJs.
基金financially supported by the National Natural Science Foundation of China(Nos.22075212 and 21925505)Natural Science Foundation of Shanghai(No.19ZR1478800)+1 种基金the program for professor of special appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning and Shanghai international scientific collaboration fund(No.21520710100)the recipient of a 5-year National Science Fund for Distinguished Young Scholars。
文摘Imatinib has been widely used as a selective kinase inhibitor for treating a variety of cancers,and this molecule is very hydrophobic so it is usually modified with mesylate salt in clinic to increase bioavailability.However,pH-dependent aqueous solubility and relatively high dosage of imatinib mesylate greatly reduce the clinical outcomes.To solve this problem,we developed an intestine enzyme-responsive hydrogel to efficiently encapsulate hydrophobic imatinib with long-term controlled release and enhanced intestinal permeability through oral administration.Methacrylic anhydride-modified carboxymethyl chitosan(MA-CMCS)was synthesized via amidation reaction and then MA-CMCS was crosslinked with photoinitator under UV-irradation to form a three-dimensional hydrophilic polymer network.The intestine enzyme responsiveness was endowed with imatinib-loaded hydrogel through hydrolyzation of glucosidic bond,which could achieve enzyme-triggered long-term drug release of up to 2 days.Furthermore,sodium deoxycholate was embedded into the hydrogel to synchronously open epithelial tight junctions with improved intestinal permeability.In vitro studies revealed similar lethality against colon cancer cell for both imatinib mesylate and imatinib-loaded hydrogels.Moreover,significantly enhanced in vivo tumor inhibition(6-fold higher compared to imatinib mesylate)was achieved after oral administration with imatinib-loaded hydrogels.Overall,this enzyme-responsive hydrogel could achieve long-term synchronous release of kinase inhibitor(imatinib)and tight junction permeation enhancer(sodium deoxycholate)at intestine with enhanced therapeutic efficiency,which could provide an effective approach to improve the bioavailability of hydrophobic anticancer chemodrugs with oral administration.
文摘Tight junctions are mainly formed by two types of proteins;claudins and occludin, both of which are fundamental to maintain the integrity and barrier function of the intestinal epithelium. This barrier function allows for the absorption of nutrients, mainly by transcytosis;however, in birds, 90% of the substances are absorbed by paracellular mechanisms. Despite this, claudins present in th<span style="font-family:Verdana;"></span><span style="font-family:;" "="">e different parts of the intestinal tract of adult chickens are not known, much less their functional role. This study aimed to determine the presence of mRNA of claudins 1, 2, 3, 5, 10, 12, 16 and occludin, in the different regions of the intestine (duodenum, jejunum, ileum, cecum, and rectum) in chickens (<i>Gallus gallus domesticus</i>) through RT-PCR. To meet this goal, 7 weeks old roosters destined for slaughter and chicken embryos of 16 days of incubation (positive control) were used. For all the processed samples, amplicons of the expected size were obtained;claudin 1 (662 pb), claudin 2 (162 pb), claudin 3 (185 pb), claudin 5 (224 pb), claudin 10 (687 pb), claudin 12 (738 pb), claudin 16 (191 pb) and occludin (430 pb). To corroborate these findings, obtained amplicons were sequenced and, subsequently, a basic alignment was performed on the NCBI, obtaining a correlation of 100% with the original sequences in all analyzed samples. To our knowledge, the present work represents the first written report regarding the presence of mRNA of the main proteins involved in tight junction formation throughout the intestinal tract of domestic chickens of 7 weeks of age. These findings will allow elucidating the specific function of each of the reported proteins in the process of paracellular absorption in chickens.</span>
文摘Background:Cells are influenced by their environment.In vivo,the corneal endothelium is subjected to intraocular pressure(IOP).The purpose of this project was to evaluate in vitro,the effect of the IOP on the formation of tight junctions in the corneal endothelium.Methods:Cultivated corneal endothelial cells(P2-P3;n=6 populations)were seeded on devitalized on corneas(n=10 pairs).Native corneas and devitalized corneas were respectively used as positive(n=2 pairs)and negative controls(n=3 pairs).Corneas were placed in artificial anterior chambers and subjected to a hydrostatic pressure between 0.3 and 0.4 psi during 4-5 days.Unpressured control corneas were maintained in cell culture dishes.Pictures of the corneas were taken following the experiment to assess stromal transparency.Morphology,corneal thickness and distribution of ZO-1,n-cadherin,b-catenin,NaK ATPase pump and HCO3-cotransporter were evaluated by electron microscopy,histological staining and immunofluorescences.Results:Pressure treated corneas were more transparent than the controls.Thickness was accordingly reduced by 38.4%±4.9%for cultivated endothelium and 32.2%±2.7%for native endothelium.Negative controls change in transparency and thickness were marginal.Pressure treated cells showed none or at most marginal difference in morphology and expression of ZO-1,n-cadherin,b-catenin,NaK ATPase pump and HCO3-cotransporters and failed to recreate a phenotype similar to native corneas.Pressure however increased cortical localisation of the protein ZO-1 in both cultivated and native endothelium.Conclusions:These results suggest that anterior chamber hydrostatic pressure may enhance endothelial functionality by modulating the distribution of tight junction’s proteins.
基金Supported by The Association for International Cancer Research(AICRto Dr.Al-Hassi HO)+6 种基金ScotlandFunded by the AICRgrant No.120234a BBSRC Strategic Research Grant(to English N and Knight SCWMNIP33458)the St Mark’s Hospital FoundationUnited Kingdom
文摘Inflammatory bowel diseases are characterised by inflammation that compromises the integrity of the epithelial barrier. The intestinal epithelium is not only a static barrier but has evolved complex mechanisms to control and regulate bacterial interactions with the mucosal surface. Apical tight junction proteins are critical in the maintenance of epithelial barrier function and control of paracellular permeability. The characterisation of alterations in tight junction proteins as key players in epithelial barrier function in inflammatory bowel diseases is rapidly enhancing our understanding of critical mechanisms in disease pathogenesis as well as novel therapeutic opportunities. Here we give an overview of recent literature focusing on the role of tight junction proteins, in particular claudins, in inflammatory bowel diseases and inflammatory bowel disease associated colorectal cancer.
基金supported by the National Natural Science Foundation of China(Nos.81803784,81320108029,and 81573690)the"Double First-Class"Projects of China Phar-macutical University(No.2018GY06)。
文摘Triptolide(TP),an active component of Tripterygium wilfordii Hook.f.(TWHF),has been widely used for centuries as a traditional Chinese medicine.However,the clinical application of TP has been restricted due to multitarget toxicity,such as hepatotoxicity.In this study,28 days of oral TP administration(100,200,or 400μg·kg^(-1)·d^(-1))induced the occurrence of cholestasis in female Wistar rats,as evidenced by increased serum levels ofγ-glutamyl transpeptidase(γ-GGT),alkaline phosphatase(ALP)and hepatic total bile acids(TBAs).In addition,the heptocyte polarity associated with the strcture of tight junctions(TJs)was disrupted in both rats and sandwich-cultured primary hepatocytes.Immunoblotting revealed decreased expression of the TJ-associated proteins occludin,claudin^(-1),and zonula occludens protein(ZO^(-1)),and downregulated m RNA levels of these TJs was also detected by real-time PCR.An immunofluorescence analysis showed abnormal subcellular localization of occludin,claudin^(-1) and ZO^(-1),which was also confirmed by transmission electron microscopy.Moreover,the concentration of FITC-dextran,a marker of paracellular penetration,was found to increase rapidly in bile increased rapidly(within 6 minutes)after treatment with TP,which indicated the functional impairment of TJs.Taken together,these results suggest that the administration of TP for 28 consecutive days to rats could induce cholestatic injury in the liver,and the increased paracellular permeability might play an important role in these pathological changes.
基金Supported by the National Natural Science Foundation of China(No.30170414)
文摘Objective：To investigate the changes of intestinal mucosa tight junctions （TJs） claudin-1, -3, -4 proteins and mRNA changes in patients with irritable bowel syndrome （IBS） and to elucidate their possible roles in the changes of bowel evacuation habit and formation. Methods： Claudin-1, -3, -4 proteins and mRNA were evaluated in intestinal mucosa in control group, D-IBS （diarrhea IBS） group and C-IBS （constipation IBS） group with immunohistochemical assay and Realtime-PCR. Results： It was observed that claudin-1, -3, -4 proteins were localized in the membranes of epithelial cells along the entire length of the plasma membrane including the apical end of the epithelial cells. The elaudins were concentrated at the site of TJs only. Claudin-1, 3, -4 mRNA and claudin-1 protein in small intestinal mucosa and colonal mucous in D-IBS group were significantly downregulated （P〈0.05）. Claudin-1, -3, -4 mRNA and proteins in small intestinal mucosa and colonal mucous in C-IBS group were significantly upregulated （P〈0. 05）. There was no significant difference in the expression of claudin-3 protein in both small intestinal mueosa and colonal mucous between D-IBS group and control group（P〉0.05）. Similarly, no significantly different expression of claudin-4 protein in colonal mucous in D-IBS group was found compared with control group （P〉0.05）. Otherwise, the expression of claudin 4 protein in small intestinal mucosa decreased in D-IBS group （P〈0.05）. Conclusion： Claudin-1, -3, -4 may play a potential important role in the changes of bowel evacuation habit and formation in patients with IBS. It is not due to the localization changes of claudin proteins in TJ, but may be caused by the quantitative changes of the expression of TJ proteins and mRNA.
基金supported by the Beijing Municipal Science and Technology Commission(Z221100002722007).
文摘The blood-brain barrier(BBB)is a barrier system separating the central nervous system from blood circulation.Connections between cells within the BBB involve specialized endothelial tight junction(TJ)proteins.BBB damage is strongly associated with numerous pathological changes in epilepsy.Endothelial cells and their TJs play a pivotal role in maintaining the BBB integrity.Astrocytes cannot directly contact endothelial cells,but the glymphatic system represents a new model to explain their relationship in epilepsy development.Leakage of albumin caused by BBB damage is a pivotal factor leading to the disruption of gap junction(GJ)function and structural abnormalities in astrocytes.Exposure to albumin from the circulation is one of the key factors in comprehending the subsequent proepileptic alterations in astrocytes resulting from BBB disruption.This review summarizes the association between the disruption of the BBB and the activation of astrocytes in epilepsy via alternation of GJs.In addition,the imaging assessment methods used for BBB damage are discussed.
基金supported by the National Natural Science Foundation of China(grants 31972908,81991500,81991502,and 32030010)Beijing Natural Science Foundation(grant 7202082).
文摘Tricellulin,a key tricellular tight junction(TJ)protein,is essential for maintaining the barrier integrity of acinar epithelia against macromolecular passage in salivary glands.This study aims to explore the role and regulatory mechanism of tricellulin in the development of salivary gland hypofunction in Sjögren’s syndrome(SS).Employing a multifaceted approach involving patient biopsies,non-obese diabetic(NOD)mice as a SS model,salivary gland acinar cell-specific tricellulin conditional knockout(TricCKO)mice,and IFN-γ-stimulated salivary gland epithelial cells,we investigated the role of tricellulin in SS-related hyposalivation.Our data revealed diminished levels of tricellulin in salivary glands of SS patients.Similarly,NOD mice displayed a reduction in tricellulin expression from the onset of the disease,concomitant with hyposecretion and an increase in salivary albumin content.Consistent with these findings,TricCKO mice exhibited both hyposecretion and leakage of macromolecular tracers when compared to control animals.Mechanistically,the JAK/STAT1/miR-145 axis was identified as mediating the IFN-γ-induced downregulation of tricellulin.Treatment with AT1001,a TJ sealer,ameliorated epithelial barrier dysfunction,restored tricellulin expression,and consequently alleviated hyposalivation in NOD mice.Importantly,treatment with miR-145 antagomir to specifically recover the expression of tricellulin in NOD mice significantly alleviated hyposalivation and macromolecular leakage.Collectively,we identified that tricellulin deficiency in salivary glands contributed to hyposalivation in SS.Our findings highlight tricellulin as a potential therapeutic target for hyposecretion,particularly in the context of reinforcing epithelial barrier function through preventing leakage of macromolecules in salivary glands.
基金Key International Cooperation Program of the National Natural Science Foundation of China(32120103011)Jiangsu Shuang Chuang Tuan Dui program(JSSCTD202147)+1 种基金Jiangsu Shuang Chuang Ren Cai program(JSSCRC2021541)Initiation Funds of Yangzhou University for Distinguished Scientists.
文摘Background The aim of this study was to determine whether and how Zn proteinate with moderate chelation strength(Zn-Prot M)can alleviate heat stress(HS)-induced intestinal barrier function damage of broilers.A completely randomized design was used for comparatively testing the effects of Zn proteinate on HS and non-HS broilers.Under high temperature(HT),a 1(Control,HT-CON)+2(Zn source)×2(added Zn level)factorial arrangement of treatments was used.The 2 added Zn sources were Zn-Prot M and Zn sulfate(ZnS),and the 2 added Zn levels were 30 and 60 mg/kg.Under normal temperature(NT),a CON group(NT-CON)and pair-fed group(NT-PF)were included.Results The results showed that HS significantly reduced mRNA and protein expression levels of claudin-1,occludin,junctional adhesion molecule-A(JAMA),zonula occludens-1(ZO-1)and zinc finger protein A20(A20)in the jejunum,and HS also remarkably increased serum fluorescein isothiocyanate dextran(FITC-D),endotoxin and interleukin(IL)-1βcontents,serum diamine oxidase(DAO)and matrix metalloproteinase(MMP)-2 activities,nuclear factor kappa-B(NF-κB)p65 mRNA expression level,and protein expression levels of NF-κB p65 and MMP-2 in the jejunum.However,dietary supplementation with Zn,especially organic Zn as Zn-Prot M at 60 mg/kg,significantly decreased serum FITC-D,endotoxin and IL-1βcontents,serum DAO and MMP-2 activities,NF-κB p65 mRNA expression level,and protein expression levels of NF-κB p65 and MMP-2 in the jejunum of HS broilers,and notably promoted mRNA and protein expression levels of claudin-1,ZO-1 and A20.Conclusions Our results suggest that dietary Zn,especially 60 mg Zn/kg as Zn-Prot M,can alleviate HS-induced intestinal barrier function damage by promoting the expression of TJ proteins possibly via induction of A20-mediated suppression of the NF-κB p65/MMP-2 pathway in the jejunum of HS broilers.
文摘Atopic dermatitis(AD)is a chronic inflammatory skin disease with xerosis,itchiness,as well as interconnection with immunoglobulin E(Ig E),mediated foods including airborne allergies.AD is not only related to the diminished stratum corneum barrier but also presents with an unusual expression of tight junctions(TJs)proteins.TJ barrier dysfunction leads to impairment in the stratum corneum(SC)barrier.The significant role of TJs in the epidermal barrier as indicated by Claudin-1(Cldn-1)deficient mice that undergo high transepidermal water loss(TEWL)and skin dehydration.In atopic dermatitis,downregulation of Cldn-1 was observed due to inflammation.Still,a lack of distinct understanding exists in considering tight junction barrier impairment as a cause or outcome in atopic dermatitis.This review summarizes TJs main role in skin barrier function and TJ proteins(TJPs)expression observed in AD patients.
基金financially supported by China Agriculture Research System (CARS-36) (2013B060400039 to 2011A020102009)National Basic Research Program of China (2013CB127301, and 2013CB127304)+1 种基金Science and Technology Planning Project of Guangdong Province (2013B060400039,2013A061401020)Special Program for Guangdong Research Institutions' Innovation and Construction(2012B060600005)
文摘This study examined effects of dietary protein sources and levels on intestinal health of 21 to 35 d-old weaned piglets fed antibiotics-free diets. A total of 150 weaned piglets(21 d of age) were allotted to 5 dietary treatment groups. Diets were formulated, based on corn-soybean meal, with different protein sources(fish meal and soy protein concentrate) to provide different dietary CP levels. Piglets within 5 dietary treatments were fed diets as follows, respectively: 1) control diet of 17% CP(control); 2) 19% CP diets formulated with more soy protein concentrate(SPC19); 3) fish meal(FM19); 4) 23.7% CP diets formulated with more soy protein concentrate(SPC23); 5) fish meal(FM23). The results showed that piglets from control group had higher ADG and lower incidence of diarrhea compared with those of other groups(P < 0.05). The incidence of diarrhea of piglets in FM19 group was lower than those from SPC23 group and FM23 group(P < 0.05). With the higher CP levels, villous height and villous height to crypt depth ratio of piglets in the duodenum and jejunum were decreased(P < 0.05), but crypt depth was increased(P < 0.05). Comparing control group and other groups, we found the expression of inflammatory cytokines interleukin-1β(IL-1β) and interferon-γ(IFN-γ) were increased(P < 0.05) in the jejunum and colon of piglets, as did cystic fibrosis transmembrane conductance regulators(CFTR) in the distal colon. The relative transcript abundance of Zonula occludens-1(ZO-1) in the jejunum, and occludin in the jejunum and ileum of piglets fed 23.7% CP diets were reduced compared with those fed control diet(P < 0.05). In conclusion, the 17% CP diet without in-feed antibiotics helped improve growth performance and relief of diarrhea of 21 to 35 d-old weaned piglets. Dietary CP level, rather than its source(either fish meal or soy protein concentrate), has more significant impacts on the growth performance and intestinal health of 21 to 35 d-old weaned piglets when fed antibiotics-free diets.
基金the National Natural Science Foundation of China(No.81903321)the Wenzhou Municipal Science and Technology Bureau(Y2020098),ChinaResearch and the Development Fund Project of Wenzhou Medical University(QTJ17019,QTJ18001),China.
文摘Objectives:This study aimed to investigate the effect of the widely used food emulsifier glycerin monostearate(GM)on testicular toxicity caused by the mixture of three commonly used phthalate esters(MPEs)in rats,and further to explore the underlying mechanism.Materials and Methods:Thirty male Sprague-Dawley rats were randomly divided into three groups.Rats were orally treated with 160 mg/kg/d MPEs in the MPEs group;coinstantaneously treated with 160 mg/kg/d MPEs and 200 mg/kg/d GM in the MPEs+GM group;and treated with the excipient in the control group.The intervention lasted for 5 weeks.Testis weight,epididymis weight,testicular histopathology,and serum testosterone were detected for testicular toxicity evaluation.The testicular ultrastructure,the tight junction proteins zonula occluden(ZO)-1,and claudin were measured for the mechanism exploration.Results:The body weight,epididymis,serum testosterone level,and anogenital distance in the MPEs+GM group were significantly decreased compared with control group(P<0.05);Testicular histopathological observation showed that shed spermatids were observed in the MPEs+GM group.Ultrastructural observation of testicular cells showed that the cristae number was decreased in some mitochondria in the MPEs group,whereas the cristae were fused and disappeared in most mitochondria in the MPEs+GM group.The tight junctions were broken in the MPEs+GM group;meanwhile,the expression of ZO-1 and claudin were altered in the MPEs+GM group(P<0.01).Conclusions:The results from this study indicated that GM aggravated MPEs'testicular toxicity,which might relate to the injured mitochondria and damaged tight junctions in testicular tissue.
基金supported by the National Natural Science Foundation of China(31501977)the Sichuan Provincial Key R&D Project China(22ZDYF0194)the Double World-Class Project of Southwest Minzu University China(XM2023010)。
文摘This study aimed to investigate the dose-effect of iron on growth performance,antioxidant function.intestinal morphology,and mRNA expression of jejunal tight junction protein in 1-to21-d-old yellow-feathered broilers.A total of 7201-d-old yellow-feathered maleb roilers were allocated to 9 treatments with 8 replicate cages of 10 birds per cage.The dietary treatments were consisted of a basal diet(contained 79.6 mg Fe kg^(-1))supplemented with 0,20,40,60,80,160,320,640,and 1,280 mg Fe kg^(-1)in the form of FeSO_(4)·7H_(2)O.Compared with the birds in the control group,birds supplemented with 20mg Fe kg^(-1)had higher average daily gain(ADG)(P<0.0001).Adding 640 and 1,280 mg Fe kg^(-1)significantly decreased ADG(P<0.0001)and average daily feed intake(ADFI)(P<0.0001)compared with supplementation of 20mg Fe kg^(-1).Malondialdehyde(MDA)concentration in plasma and duodenum increased linearly(P<0.0001),but MDA concentration in liver and jejunum increased linearly(P<0.05)or quadratically(P<0.05)with increased dietary Fe concentration.The villus height(VH)in duodenum and jejunum,and the ratio of villus height to crypt depth(V/C)in duodenum decreased linearly(P?0.05)as dietary Feincreased.As dietary Fe increased,the jejunal relative mRNA abundance of claudin-1 decreased linearly(P=0.001),but the jejunal relative mRNA abundance of zona occludens-1(ZO-1)and occludin decreased linearly(P?0.05)or quadratically(P?0.05).Compared with the supplementation of 20 mg Fe kg^(-1),the supplementation of640 mg Fe kg^(-1)or higher increased(P?0.05)MDA concentrations in plasma,duodenum,and jejunum,decreased VH in the duodenum and jejunum,and the addition of 1,280 mg Fe kg^(-1)reduced(P?0.05)the jejunal tight junction protein(claudin-1,ZO-1,occludin)mRNA abundance.In summary,640 mg of supplemental Fe kg^(-1)or greater was associated with decreased growth performance,increased oxidative stress,disrupted intestinal morphology,and reduced mRNA expression of jejunal tight junction protein.
文摘The brain’s blood microvessels restrict the exchange of substances between the blood and brain tissue through the blood-brain barrier (BBB). Methyl-glyoxal (MG), a byproduct of glucose metabolism, contributes to the formation of advanced glycation end products (AGEs) and disrupts the BBB, which is associated with neurodegenerative diseases. L-Theanine (TA), an amino acid found in green tea with antioxidant properties, may protect the BBB. This study aimed to determine whether MG increases reactive oxygen species (ROS) and permeability by reducing tight junction proteins in human cerebral microvascular endothelial cells (hCMEC/d3), and whether TA pretreatment can counteract these effects. Our findings demonstrated that MG treatment led to increased BBB permeability, decreased transendothelial electrical resistance (TEER) values to 39% of control levels, reduced expression of Claudin-5 to 53% and Occludin to 69% of control levels, and elevated intracellular ROS levels. TA pretreatment restored barrier integrity, preserved tight junction protein expression, and decreased ROS accumulation to levels comparable to control levels. These findings suggest that TA effectively prevents MG-induced BBB dysfunction by reducing oxidative stress and maintaining tight junction proteins, showing promise as a protective agent for the BBB in conditions associated with elevated MG and AGEs.
