Responses of growth performance,antioxidant function,small intestinal morphology and mRNA expression of jejunal tight junction protein to dietary iron in 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.

Dietary protocatechuic acid ameliorates inflammation and up-regulates intestinal tight junction proteins by modulating gut microbiota in LPS-challenged piglets

Background: Weaning is one of the major factors that cause stress and intestinal disease in piglets. Protocatechuic acid(PCA) is an active plant phenolic acid which exists in Chinese herb, Duzhong(Eucommia ulmoides Oliver), and is also considered as the main bioactive metabolite of polyphenol against oxidative stress and inflammation. This study aimed to investigate the effect of PCA on growth performance, intestinal barrier function, and gut microbiota in a weaned piglet model challenged with lipopolysaccharide(LPS).Methods: Thirty-six piglets(Pig Improvement Company line 337 × C48, 28 d of age, 8.87 kg ± 0.11 kg BW) were randomly allocated into 3 treatments and fed with a basal diet(CTL), a diet added 50 mg/kg of aureomycin(AUR), or a diet supplemented with 4000 mg/kg of PCA, respectively. The piglets were challenged with LPS(10 μg/kg BW) on d 14 and d 21 by intraperitoneal injection during the 21-d experiment. Animals(n = 6 from each group) were sacrificed after being anesthetized by sodium pentobarbital at 2 h after the last injection of LPS. The serum was collected for antioxidant indices and inflammatory cytokines analysis, the ileum was harvested for detecting mRNA and protein levels of tight junction proteins by PCR and immunohistochemical staining, and the cecum chyme was collected for intestinal flora analysis using 16 S rRNA gene sequencing.Results: Dietary supplementation of PCA or AUR significantly increased the expression of tight junction proteins including ZO-1 and claudin-1 in intestinal mucosa, and decreased the serum levels of thiobarbituric acid reactive substances(TBARS) and IL-6, as compared with CTL group. In addition, PCA also decreased the serum levels of IL-2 and TNF-α(P < 0.05). Analysis of gut microbiota indicated that PCA increased the Firmicutes/Bacteroidetes ratio(P < 0.05). Spearman's correlation analysis at the genus level revealed that PCA reduced the relative abundance of Prevotella 9, Prevotella 2, Holdemanella, and Ruminococcus torques group(P < 0.05), and increased the relative abundance of Roseburia and Desulfovibrio(P < 0.05), whereas AUR had no significant effect on these bacteria.Conclusions: These results demonstrated that both PCA and AUR had protective effect on oxidative stress, inflammation and intestinal barrier function in piglets challenged with LPS, and PCA potentially exerted the protective function by modulating intestinal flora in a way different from AUR.

Effect of tight junction protein of intestinal epithelium and permeability of colonic mucosa in pathogenesis of injured colonic barrier during chronic recovery stage of rats with inflammatory bowel disease

Objective: To discuss the changes in the tight junction protein of intestinal epithelium and permeability of colonic mucosa and its possible mechanism by building the rat mode of inflammatory bowel disease at the chronic recovery stage. Methods: A total of 36 SD rats were divided into the model group and control one according to the random number table, with 18 rats in each group. Rats in the model group were given the 3% dextran sulfate sodium solution by the way of drinking for 7 d to build the rat model of inflammatory bowel disease, while rats in the control group were given free drinking of water. Six rats were executed at day 7, 14 and 21 respectively. The colonic tissues were collected from rats to observe the pathological changes of colonic mucosa. The activity of myeloperoxidase was detected and the white blood count was performed for rats in each group. The Ussing chamber technique was employed to detect the transepithelial electrical resistance(TER) and short-circuit current(SC) of colonic mucosa of rats in different time intervals; the quantum dots labeling technique was employed to detect the expression level of claudin-1 and claudin-2 in the colonic tissues. Results: After the successful modeling, the weight of rats in the model group was significantly reduced, while the disease activity index score was increased. The weight was at the lowest level at day 14 and then it began to increase afterwards. The disease activity index score was at the highest level at day 12 and then it began to decrease gradually. The activity of myeloperoxidase and WBC for rats in the model group all reached the peak value at day 14 and then decreased gradually. There was no significant difference in the changes of TER and SC in different time intervals for rats in the control group(P>0.05). TER of model group was at the lowest level at day 14 and then increased gradually; SC was at the highest level at day 14 and then decreased gradually. TER of model group at day 7, 14 and 21 was significantly lower than that of control group, while SC of model group was significantly higher than that of control group(P<0.05). There was no significant difference in the change of mean fluorescence intensity of claudin-1 and claudin-2 in different time intervals for rats in the control group(P>0.05). The claudin-1 and claudin-2 for rats in the model group reached the highest level at day 14 and then decreased gradually. The claudin-1 and claudin-2 of model group at day 7, 14 and 21 was significantly higher than that of control group(P<0.05). Conclusions: After the acute stage, the inflammatory bowel disease is then in the chronic recovery stage; the increased permeability of colonic mucosa and increased expression of tight junction protein of intestinal epithelium are closely related to the pathogenesis and development of disease. The tight junction protein plays a key role in the pathogenesis of injured colonic barrier of inflammatory bowel disease.

Effects of Simulated Weightlessness on Tight Junction Protein Occludin and Zonula Occluden-1 Expression Levels in the Intestinal Mucosa of Rats

This study investigated the tight junction（TJ） protein expression of the intestinal mucosa in a rat tail-suspension model under simulated weightlessness.Twenty-four Wistar rats were randomly divided into three groups：CON group（n=8）,control; SUS-14 d group（n=8）,tail-suspension for 14 days; SUS-21 d group（n=8）,tail-suspension for 21 days.Occludin and Zonula Occluden-1（ZO-1） expression levels were determined by immunohistochemical analysis and mRNA fluorescent quantitative PCR.Plasma levels of diamine oxidase（DAO） and d-lactate were determined using enzymatic spectrophotometry.Immunohistochemical results for occludin and ZO-1 showed disruption of the TJs in the intestinal mucosa in SUS-14 d and SUS-21 d groups.The expression levels of occludin and ZO-1 in SUS-21 d group were lower than those in SUS-14 d group,and significantly lower than those in CON group（Occldin：0.86±0.02 vs 1.01±0.03 vs 1.63±0.03 and ZO-1：0.82±0.01 vs 1.00±0.02 vs 1.55±0.01,P〈0.01）.Moreover,the levels of plasma DAO and d-lactate in SUS-21 d group were higher than those in SUS-14 d group,and significantly higher than those in CON group（DAO：27.58±0.49 vs 20.74±0.49 vs 12.94±0.21 and d-lactate：37.86±0.74 vs 28.26±1.01 vs 17.76±0.91,P〈0.01）.There were significant negative correlations between occludin or ZO-1 expression levels and DAO（r2=0.9014,r2=0.9355,P〈0.01） or d-lactate levels（r2=0.8989,r2=0.9331,P〈0.01）.Occludin and Zo-1 were reduced in intestinal mucosa both in mRNA and protein levels in the rat tail-suspension model.The significant negative correlations between expression levels of TJs and plasma levels of DAO or d-lactate support the hypothesis that intestinal permeability is increased due to a decrease in TJ protein expression during tail-suspension from 14 days to 21 days.

New tight junction protein 2 variant causing progressive familial intrahepatic cholestasis type 4 in adults: A case report

BACKGROUND Progressive familial intrahepatic cholestasis(PFIC)encompasses a group of autosomal recessive disorders with high morbidity and mortality.Variants in the gene encoding tight junction protein-2(TJP2)have been linked to PFIC type 4(PFIC4),which predominantly presents in childhood.However,there are only limited data from adults with TJP2-related PFIC4.We report a family with an autosomal recessive disorder with a novel variant in the TJP2 gene in adults with very variable expression of PFIC4.CASE SUMMARY The index patient presented at 19 years old with liver cirrhosis and variceal bleeding and was treated with endoscopic banding and beta-blockers.In 2018,he developed primary liver cancer that was treated with radiofrequency ablation followed by liver transplantation in 2019.Genetic testing revealed a novel homozygous TJP2 variant causing PFIC4(TJP2([NM_004817.3]:c.[3334C>T];[3334C>T])).The consanguineous family consists of the father and mother(both heterozygous)and their 12 children,of which five carry the variant in a homozygous state;however,these five siblings have highly variable expression of PFIC4.Two homozygous brothers had cirrhosis and portal hypertension at diagnosis at the ages of 19 and 36.Two other homozygous brothers,age 23 and 19,and the homozygous sister,age 21,have elevated liver enzymes but presently no cirrhosis,which may suggest an age-dependent penetrance.In addition,five sisters had severe and mild intrahepatic cholestasis of pregnancy and carry the TJP2 variant in a homozygous and heterozygous state,respectively.CONCLUSION This novel TJP2 variant is associated with PFIC4 causing severe liver disease with cirrhosis and primary liver cancer in adolescents/adults.

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.

Effect of salvianolate on intestinal epithelium tight junction protein zonula occludens protein 1 in cirrhotic rats

AIM:To study the effect of salvianolate on tight junctions(TJs) and zonula occludens protein 1(ZO-1) in small intestinal mucosa of cirrhotic rats.METHODS:Cirrhosis was induced using carbon tetrachloride.Rats were randomly divided into the untreated group,low-dose salvianolate(12 mg/kg) treatment group,medium-dose salvianolate(24 mg/kg) treatment group,and high-dose salvianolate(48 mg/kg) treatment group,and were treated for 2 wk.Another 10 healthy rats served as the normal control group.Histological changes in liver tissue samples were observed under a light microscope.We evaluated morphologic indices of ileal mucosa including intestinal villi width and thickness of mucosa and intestinal wall using a pathological image analysis system.Ultrastructural changes in small intestinal mucosa were investigated in the five groups using transmission electron microscopy.The changes in ZO-1 expression,a tight junction protein,were analyzed by immunocytochemistry.The staining index was calculated as the product of the staining intensity score and the proportion of positive cells.RESULTS:In the untreated group,hepatocytes showed a disordered arrangement,fatty degeneration was extensive,swelling was obvious,and disorganized lobules were divided by collagen fibers in hepatic tissue,which were partly improved in the salvianolate treated groups.In the untreated group,abundant lymphocytes infiltrated the fibrous tissue with proliferation of bile ducts,and collagen fibers gradually decreased and damaged hepatic lobules were partly repaired following salvianolate treatment.Compared with the untreated group,no differences in intestinal villi width between the five groups were observed.The villi height as well as mucosa and intestinal wall thickness gradually thickened with salvianolate treatment and were significantly shorter in the untreated group compared with those in the salvianolate treatment groups and normal group(P < 0.01).The number of microvilli decreased and showed irregular lengths and arrangements in the untreated group.The intercellular space between epithelial cells was wider.The TJs were discontinuous,which indicated disruption in TJ morphology in the untreated group.In the treated groups,the microvilli in the intestinal epithelium were regular and the TJs were gradually integrated and distinct.The expression of ZO-1 decreased in the small intestine of the untreated cirrhotic rats.The high expression rate of ZO-1 in ileal mucosa in the untreated group was significantly lower than that in the medium-dose salvianolate group(21.43% vs 64.29%,χ 2 = 5.25,P < 0.05),high-dose salvianolate group(21.43% vs 76.92%,χ 2 = 8.315,P < 0.01) and normal group(21.43% vs 90%,χ 2 = 10.98,P < 0.01).CONCLUSION:Salvianolate improves liver histopathological changes,repairs intestinal mucosa and TJ structure,and enhances ZO-1 expression in the small intestinal mucosa in cirrhotic rats.

Protective Effect of Simvastatin on Impaired Intestine Tight Junction Protein ZO-1 in a Mouse Model of Parkinson's Disease

Summary： Recently, several studies showed that gastrointestinal tract may be associated with patho- physiology of Parkinson＇s disease （PD）. Intestine tight junction protein zonula occluden-1 （ZO-1） is an important component of intestinal barrier which can be degraded by matrix metallopeptidase 9 （MMP-9）. In our previous study, a significant decline in ZO-1 was observed along with enhanced MMP-9 activity in the duodenum and distal colon of 1-methyl-4-phenyl-l,2,3,6-tetrahydropyridine （MPTP）-intoxicated mice. In this study, the protective effect of simvastatin on ZO-1 was investigated using an MPTP mouse model of PD. Seven days after the end of MPTP application, the expression level of ZO-1 was evaluated by immunohistochemistry. The protein expression levels of ZO-1 and MMP9 were detected by Western blotting. Meanwhile, MMP-9 activity was analyzed by gelatin zymography. MPTP treatment led to a decrease in the expression of ZO-1, which was accompanied by elevated MMP-9 activity. Treatment with simvastatin could partly reverse the MPTP-induced changes in ZO-I expression and reduce MMP-9 protein and activity. Taken together, these findings suggest that simvas- tatin administration may partially reverse the impairment of ZO-1 induced by MPTP via inhibiting the activity of MMP9, fortify the impaired intestinal barrier and limit gut-derived toxins that＇pass across the intestinal barrier.

Preliminary Investigation on the Effect of <i>Lactobacillus</i>and Epidermal Growth Factor on Tight Junction Proteins in Experimental Clostridium <i>difficile</i>Infection

Clostridium difficile associated disease (CDAD) is the most common hospital acquired infection, due to exposure to various drugs. C. difficile toxins influence barrier function in intestinal epithelium. Biotherapeutic approaches, employing probiotic and epidermal growth factor (EGF) could help in barrier protein protection and aid in CDAD management. A preliminary investigation on the effect of Lactobacillus acidophilus and EGF on tight junction proteins in experimentally induced C. difficile infection was done. BALB/mice were divided into 5 groups. Group 1 was comprised of healthy controls, whereas animals in Groups 2 - 5 were sub-divided into 3 subgroups (a, b and c) each. Animals in Groups 2 - 5 received C. difficile inoculum either on day 1 (Group 2) or after pretreatment with ampicillin (Group 3), cyclosporine (Group 4) or lansoprazole (Group 5). Additionally animals in subgroups “b” and “c” also received L. acidophilus and EGF inocula respectively after C. difficile challenge. All animals were investigated for the presence of tight junction proteins (occludin, α-actinin and zonula occludens) in their colonic segments. Data were analyzed using the SPSS version 10 software. These three proteins were present in significantly less (P < 0.05) number of animals in the drug receiving animals, whereas they were found in significantly more (P < 0.05) number of animals receiving L. acidophilus and EGF after challenge with ampicillin, cyclosporine and lansoprazole, suggesting their role in protecting intestinal barrier function.

Side-stream smoking reduces intestinal inflammation and increases expression of tight junction proteins

AIM:To investigate the effect of side-stream smoking on gut microflora composition,intestinal inflammation and expression of tight junction proteins.METHODS:C57BL/6 mice were exposed to side-stream cigarette smoking for one hour daily over eight weeks.Cecal contents were collected for microbial composition analysis.Large intestine was collected for immunoblotting and quantitative reverse transcriptase polymerase chain reaction analyses of the inflammatory pathway and tight junction proteins.RESULTS:Side-stream smoking induced significant changes in the gut microbiota with increased mouse intestinal bacteria,Clostridium but decreased Fermicutes(Lactoccoci and Ruminococcus),Enterobacteriaceae family and Segmented filamentous baceteria compared to the control mice.Meanwhile,side-stream smoking inhibited the nuclear factor-κB pathway with reduced phosphorylation of p65 and IκBα,accompanied with unchanged mRNA expression of tumor necrosis factor-α or interleukin-6.The contents of tight junction proteins,claudin3 and ZO2 were up-regulated in the large intestine of mice exposed side-stream smoking.In addition,side-stream smoking increased c-Jun N-terminal kinase and p38 MAPK kinase signaling,while inhibiting AMPactivated protein kinase in the large intestine.CONCLUSION:Side-stream smoking altered gut microflora composition and reduced the inflammatory response,which was associated with increased expression of tight junction proteins.

Moxibustion combined with acupuncture increases tight junction protein expression in Crohn's disease patients

AIM:To investigate the effect of herb-partitioned moxibustion combined with acupuncture on the expression of intestinal epithelial tight junction(TJ) proteins.METHODS:Sixty patients diagnosed with mild to moderate Crohn’s disease(CD)were allocated into the herb-partitioned moxibustion combined with acupuncture(HMA)group(n=30)or the mesalazine(MESA)group(n=30)using a parallel control method.There were 2 sets of acupoints used alternately for HMA treatment.The following points were included in Set A:ST25(Tianshu),RN6(Qihai),and RN9(Shuifen)for herb-partitioned moxibustion and ST36(Zusanli),ST37(Shangjuxu),LI11(Quchi),and LI4(Hegu)for acupuncture.The points for Set B included BL23(Shenshu)and BL25(Dachangshu)for herb-partitioned moxibustion and EX-B2 of T6-T1(Jiajixue)fo r acupuncture.The patients received the same treatment6 times a week for 12 consecutive weeks.The MESA group received 1 g of mesalazine enteric coated tablets4 times daily for 12 consecutive weeks.Intestinaltissues were stained and examined to compare the morphological and ultrastructural changes before and after the treatment session.Immunohistochemistry and in situ hybridization assays were used to detect the expression of intestinal epithelial TJ proteins zonula occludens-1(ZO-1),occludin,and claudin-1.The m RNA levels were also evaluated.RESULTS:After the treatment,both herb-partitioned moxibustion combined with acupuncture and mesalazine improved intestinal morphology and ultrastructure of CD patients;the patients treated with HMA showed better improvement.HMA significantly increased the expression of ZO-1(P=0.000),occludin(P=0.021),and claudin-1(P=0.016).MESA significantly increased the expression of ZO-1(P=0.016)and occludin(P=0.026).However,there was no significant increase in the expression of claudin-1(P=0.935).There was no statistically significant difference between the two groups for the expression of occludin and claudin-1(P>0.05).The HMA group showed a significant improvement in ZO-1 expression compared to the MESA group(2333.34±352.51 vs 2160.38±307.08,P=0.047).HMA significantly increased the expression of ZO-1 m RNA(P=0.000),occludin m RNA(P=0.017),and claudin-1 m RNA(P=0.017).MESA significantly increased the expression of ZO-1 m RNA(P=0.000),occludin m RNA(P=0.042),and claudin-1 m RNA(P=0.041).There was no statistically significant difference between the two groups in the expression of occludin and claudin-1 m RNA(P>0.05).However,the HMA group showed a significant improvement in ZO-1 m RNA expression compared with the MESA group(2378.17±308.77 vs 2200.56±281.88,P=0.023).CONCLUSION:HMA can repair intestinal epithelial barrier lesions and relieve inflammation by upregulating the expression of TJ proteins and their m RNAs.

Nimbolide inhibits tumor growth by restoring hepatic tight junction protein expression and reduced inflammation in an experimental hepatocarcinogenesis

BACKGROUND Altered tight junction(TJ)proteins are correlated with carcinogenesis and tumor development.Nimbolide is a tetranotriterpenoid that has been shown to have antioxidant and anti-proliferative properties;however,its anticancer effects and molecular mechanism in hepatocellular carcinoma(HCC)remains obscure.AIM To investigate the effect of nimbolide on TJ proteins,cell cycle progression,and hepatic inflammation in a mouse model of HCC.METHODS HCC was induced in male Swiss albino mice(CD-1 strain)by a single intraperitoneal injection of 100 mg/kg diethylnitrosamine(DEN)followed by 80 ppm N-nitrosomorpholine(NMOR)in drinking water for 28 wk.After 28 wk,nimbolide(6 mg/kg)was given orally for four consecutive weeks in DEN/NMOR induced HCC mice.At the end of the 32nd week,all the mice were sacrificed and blood and liver samples were collected for various analyses.Macroscopic examinations of hepatic nodules were assessed.Liver histology and HCC tumor markers such as alpha-fetoprotein(AFP)and glypican-3 were measured.Expression of TJ proteins,cell proliferation,and cell cycle markers,inflammatory markers,and oxidative stress markers were analyzed.In silico analysis was performed to confirm the binding and modulatory effect of nimbolide on zonula occludens 1(ZO-1),nuclear factor of kappa light polypeptide gene enhancer in B-cells(NF-κB),and tumor necrosis factor alpha(TNF-α).RESULTS We found nimbolide treatment at a concentration of 6 mg/kg to HCC mice reduced hepatic tumor size by 52.08%and tumor volume(P<0.01),and delayed tumor growth in HCC mice with a concomitant reduction in tumor markers such as AFP levels(P<0.01)and glypican-3 expression(P<0.05).Furthermore,nimbolide treatment increased tight junction proteins such as ZO-1 and occludin expression(P<0.05,respectively)and reduced ZO-1 associated nucleic acid binding protein expression(P<0.001)in HCC mice liver.Nimbolide treatment to HCC mice also inhibited cell proliferation and suppressed cell cycle progression by attenuating proliferating cell nuclear antigen(P<0.01),cyclin dependent kinase(P<0.05),and CyclinD1(P<0.05)expression.In addition,nimbolide treatment to HCC mice ameliorated hepatic inflammation by reducing NF-κB,interleukin 1 beta and TNF-αexpression(P<0.05,respectively)and abrogated oxidative stress by attenuating 4-hydroxynonenal expression(P<0.01).Molecular docking studies further confirmed that nimbolide interacts with ZO-1,NF-κB,and TNF-α.CONCLUSION Our current study showed for the first time that nimbolide exhibits anticancer effect by reducing tumor size,tumor burden and by suppressing cell cycle progression in HCC mice.Furthermore,nimbolide treatment to HCC mice ameliorated inflammation and oxidative stress,and improved TJ proteins expression.Consequently,nimbolide could be potentially used as a natural therapeutic agent for HCC treatment,however further human studies are warranted.

Effect of Clostridium perfringens enterotoxin on gastric cancer cells SGC7901 which highly expressed claudin-4 protein

AIM To investigate the effects of Clostridium perfringens enterotoxin(CPE) on gastric cancer cells which highly expressed claudin-4(CL4) protein.METHODS In this study, we detected expression of CL4 protein in different gastric cancer cell lines. Then, we investigated the effects of CPE on SGC7901 cells which highly expressed CL4 protein and the effects of CPE on sub-cutaneous tumor in nude mice models.RESULTS CL4 are highly expressed in SGC7901 cells. CPE expressedsignificant cytotoxicity in SGC7901 cells. Suppression of CL4 expression significantly decreased CPE-mediated cytotoxicity. CPE also inhibited tumor growth in subcutaneous tumor xenograft models.CONCLUSION CPE showed CL4 mediated cytotoxicity on gastric cancer cells SGC7901 and inhib-ited tumor growth in nude mice models.

Targeting tight junctions during epithelial to mesenchymal transition in human pancreatic cancer

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.

脂多糖处理时间对山羊瘤胃上皮细胞损伤的影响

在山羊瘤胃上皮细胞(GRECs)基础培养基中加入1μg/mL脂多糖(LPS),培养3、6、9 h后,检测细胞活性、抗氧化指标、炎症因子及紧密连接蛋白基因的表达。结果发现:1)LPS处理3 h组GRECs的活性显著低于处理6 h和9 h组的,而处理6 h和9 h组GRECs的活性无显著差异;2)LPS处理3 h组GRECs的谷胱甘肽过氧化物酶(GSH–PX)活性极显著低于处理6 h和9 h组的,但MDA含量的变化则相反,GRECs的SOD和CAT活性随LPS处理时间的延长而显著升高,ROS含量则随LPS处理时间的延长而极显著降低;3)LPS处理3h组GRECs的TNF–ɑ和IL–1β相对表达量极显著高于处理6h和9h组的,IL–1β相对表达量随LPS处理时间的延长而显著降低,各组间IL–6相对表达量无显著差异;4)LPS处理3 h组GRECs的ZO–1分布低,随着处理时间延长ZO–1分布增加,LPS处理3 h的GRECs紧密连接蛋白Claudin–1相对表达量显著高于处理6 h和9 h组的。说明随着LPS处理时间的延长,山羊瘤胃上皮细胞能够通过提高自身抗氧化和抗炎症能力来缓解氧化损伤,进而改善细胞屏障功能。

VSAP磷酸化介导紧密连接蛋白参与保护脓毒症肠上皮屏障功能

目的:验证紧密连接蛋白ZO-1、Claudin-5和Occludin保护脓毒症肠屏障功能与血管扩张刺激磷蛋白(vasodilator-stimulated phosphoprotein, VASP)相关。方法:盲肠结扎穿孔术构建脓毒症小鼠模型,实验分为:对照组、假手术组、模型组和VASP磷酸化(p-VASP)激动剂Bucladesine组。ELISA检测血清中二胺氧化酶(DAO)和D-乳酸(D-LA)含量。HE染色观察小肠黏膜组织形态。TUNEL染色检测小肠上皮细胞凋亡。Western blotting检测Bax、Bcl-2、p-VASP、ZO-1、Occludin和claudin-5蛋白表达水平。结果:与对照组和假手术组相比,模型组中小肠绒毛数量减少、绒毛断裂、TUNEL阳性细胞增加、DAO和D-LA含量升高(P<0.05),Bax蛋白、p-VASP蛋白表达水平升高(P<0.05),ZO-1、Occludin和claudin-5蛋白、Bcl-2蛋白表达水平降低(P<0.05)。与模型组相比,Bucladesine组中小肠绒毛数量增加、绒毛断裂减少、TUNEL阳性细胞减少、DAO和D-LA含量降低(P<0.05),p-VASP蛋白表达水平降低(P<0.05),ZO-1、Occludin和claudin-5蛋白表达水平升高(P<0.05)。结论:抑制脓毒症小鼠p-VASP后小肠上皮屏障功能恢复,这与上调紧密连接蛋白表达水平有关。

饲粮锌缺乏对22~42日龄肉仔鸡生长性能、小肠形态、屏障功能及空肠中紧密连接蛋白mRNA表达的影响

本试验旨在研究饲粮锌缺乏对22~42日龄肉仔鸡生长性能、小肠形态、屏障功能及空肠中紧密连接蛋白mRNA表达的影响。试验选用140只1日龄爱拔益加肉仔鸡公雏,1~21日龄统一饲喂正常添加七水合硫酸锌(ZnSO 4·7H 2O)的试验饲粮(实测锌含量为84.40 mg/kg);22日龄时,从中选取体重接近的112只肉仔鸡,采用单因子完全随机试验设计,随机分为2组(每组7个重复,每个重复8只鸡),对照组饲喂满足肉仔鸡锌需要量的试验饲粮(基础饲粮中添加40 mg/kg锌,实测锌含量为64.36 mg/kg),锌缺乏组饲喂不添加锌的试验饲粮(基础饲粮中不添加锌,实测锌含量为22.23 mg/kg)。试验期42 d。结果表明,与对照组相比:1)锌缺乏组22~42日龄肉仔鸡料重比显著增加(P<0.05);2)锌缺乏组42日龄肉仔鸡十二指肠和空肠隐窝深度显著增加(P<0.05),42日龄肉仔鸡十二指肠、空肠和回肠绒毛高度/隐窝深度以及空肠绒毛高度和绒毛表面积显著降低(P<0.05);3)锌缺乏组42日龄肉仔鸡翅静脉和肝门静脉血清二胺氧化酶活性和异硫氰酸荧光素-葡聚糖含量显著增加(P<0.05);4)锌缺乏组42日龄肉仔鸡空肠中黏膜闭合蛋白-1(Claudin-1)的mRNA表达水平显著降低(P<0.05)。综上所述,饲粮锌缺乏可能通过降低紧密连接蛋白Claudin-1的mRNA表达而损伤肉仔鸡小肠黏膜完整性和屏障功能,进而降低其饲料转化效率。

人脐带间充质干细胞来源外泌体降低脊髓损伤后血脊髓屏障的通透性

背景:研究发现,内皮素参与了脊髓损伤后血脊髓屏障的破坏,干细胞来源外泌体可降低血脊髓屏障的通透性,修复脊髓损伤。目的:观察人脐带间充质干细胞来源外泌体是否可以通过抑制内皮素1表达降低血脊髓屏障的通透性,进而修复脊髓损伤。方法:用超速离心法从人脐带间充质干细胞培养上清液中提取外泌体,透射电子显微镜观察其形态,Western blot检测tsg101、CD63的表达。80只SD大鼠随机分成假手术组、模型组、外泌体组、内皮素1组(n=20),采用改良Allen’s法制备大鼠脊髓损伤模型,内皮素1组用微量注射器直接向损伤部位注射10μL(1μg/mL)内皮素1,术后即刻及1,2 d,分别给予假手术组、模型组尾静脉注射200μL PBS,外泌体组、内皮素1组尾静脉注射200μL外泌体(200μg/mL)。脊髓损伤后第1,3,7,14,21天进行后肢运功功能评分;损伤后第7天通过伊文思蓝染色观察血脊髓屏障通透性,Western blot检测脊髓组织中紧密连接蛋白ZO-1、β-Catenin、Occludin和内皮素1的表达。结果与结论:①外泌体组BBB评分在损伤后3-21 d显著高于模型组(P<0.05),苏木精-伊红染色显示外泌体组脊髓损伤较模型组明显减轻;内皮素1组BBB评分较外泌体组显著降低(P<0.05),内皮素1组脊髓损伤较外泌体组加重;②模型组内皮素1表达量较假手术组显著增加(P<0.05),外泌体组内皮素1表达量较模型组显著降低(P<0.05);③与模型组比较,外泌体组血脊髓屏障伊文思蓝渗出量显著减少(P<0.05),紧密连接蛋白β-Catenin、Occludin、ZO-1的表达增加(P<0.05);与外泌体组比较,内皮素1组伊文思蓝渗出量显著增加(P<0.05),上述紧密连接蛋白表达量显著减少(P<0.05);④结果表明,人脐带间充质细胞来源外泌体通过下调内皮素1表达来保护血脊髓屏障的通透性,起到了修复脊髓损伤的作用。

TNF-α下调大鼠肺微血管内皮细胞紧密连接蛋白ZO-1、Claudin-5的表达

目的:研究肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)对大鼠肺微血管内皮细胞紧密连接蛋白1(zonula oc⁃cludens-1,ZO-1)、Claudin-5表达的影响,探讨TNF-α对大鼠肺血管屏障的损伤机制。方法:将体外培养的大鼠肺微血管内皮细胞分为对照组、TNF-α24 h、48 h和72 h组(TNF-α10 mg/L)。透射电镜观察大鼠肺微血管内皮细胞超微结构。MTT法及流式细胞仪分别测定各组细胞的增殖抑制率及凋亡率。免疫荧光法测定ZO-1及Claudin-5的分布。RT-qPCR及Western blot测定各组细胞ZO-1及Claudin-5的mRNA及蛋白表达。结果:对照组内皮细胞含有大量的线粒体及内质网等结构,结构正常。TNF-α各组细胞线粒体数量减少,线粒体肿胀,嵴溶解,核固缩,凋亡细胞增多,细胞增殖抑制率及凋亡率较对照组增加(均P<0.05),呈时间依赖性。ZO-1及Claudin-5呈线状荧光分布于内皮细胞间连接部位。与对照组比较,TNF-α各组细胞ZO-1的转录及表达水平均降低(均P<0.05)。TNF-α各组Claudin-5的转录水平较对照组明显降低(均P<0.05),TNF-α48 h、72 h组Claudin-5的蛋白表达水平较对照组降低(均P<0.05),TNF-α24 h组与对照组比较差异无统计学意义(P>0.05)。结论:TNF-α下调大鼠微血管内皮细胞ZO-1及Claudin-5的表达,诱导细胞损伤及凋亡,破坏肺屏障,导致肺损伤。

2种抗生素对大黄鱼肠道组织及紧密连接蛋白基因表达的影响

为探究盐酸多西环素和恩诺沙星对大黄鱼肠道结构及肠道紧密连接蛋白相关基因表达的影响,在水温16.80~22.50℃下,将体质量(41.57±1.63)g的大黄鱼饲养在直径1 m、水深1.25 m的圆形塑料水槽中,投喂剂量0、0.2、1.0、2.0 g/kg的药饵5~7 d,停药后1、5、15 d,观察肠道组织形态变化,测定紧密连接蛋白基因Claudin-7、ZO-1和Occludin的相对表达量。试验结果显示:大黄鱼摄食2种药物后,肠道均出现肠绒毛萎缩,组织空泡化等病变,随着给药剂量的增加和给药时间的延长,肠道组织损伤程度逐渐加深,紧密连接蛋白基因表达量持续降低;肠黏膜损伤在停药15 d后仍未恢复至对照组水平,药物剂量越高恢复程度越低;与对照组相比,2种药物高剂量组紧密连接蛋白基因表达量在停药15 d后仍显著低于对照组(P<0.05),其余组无显著差异(P>0.05)。试验结果表明,盐酸多西环素和恩诺沙星以剂量时间依赖方式损伤大黄鱼肠道组织,降低肠道通透性,药物剂量越高,恢复周期越长,在15 d后仍未完全恢复。