• Animal Bioscience
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• v.36 no.9
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• pp.1403-1413
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• 2023

Objective: Intestinal alkaline phosphatase (IAP) maintains intestinal homeostasis by detoxifying bacterial endotoxins and regulating gut microbiota, and lipid absorption. Antibiotics administered to animals can cause gut dysbiosis and barrier disruption affecting animal health. Therefore, the present study sought to investigate the role of IAP in the intestinal environment in dysbiosis. Methods: Young male mice aged 9 weeks were administered a high dose of antibiotics to induce dysbiosis. They were then sacrificed after 4 weeks to collect the serum and intestinal organs. The IAP activity in the ileum and the level of cytokines in the serum samples were measured. Quantitative real-time polymerase chain reaction analysis of RNA from the intestinal samples was performed using primers for tight junction proteins (TJPs) and proinflammatory cytokines. The relative intensity of IAP and toll-like receptor 4 (TLR4) in intestinal samples was evaluated by western blotting. Results: The IAP activity was significantly lower in the ileum samples of the dysbiosis-induced group compared to the control. The interleukin-1 beta, interleukin-6, and tumor necrosis factor-alpha concentrations were significantly higher in the ileum samples of the dysbiosis-induced group. The RNA expression levels of TJP2, claudin-3, and claudin-11 showed significantly lower values in the intestinal samples from the dysbiosis-induced mice. Results from western blotting revealed that the intensity of IAP expression was significantly lower in the ileum samples of the dysbiosis-induced group, while the intensity of TLR4 expression was significantly higher compared to that of the control group without dysbiosis. Conclusion: The IAP activity and relative mRNA expression of the TJPs decreased, while the levels of proinflammatory cytokines increased, which can affect intestinal integrity and the function of the intestinal epithelial cells. This suggests that IAP is involved in mediating the intestinal environment in dysbiosis induced by antibiotics and is an enzyme that can potentially be used to maintain the intestinal environment in animal health care.

• Journal of Microbiology and Biotechnology
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• v.33 no.8
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• pp.1057-1065
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• 2023

Inflammatory bowel disease (IBD), a chronic inflammatory disease, results from dysregulation of the immune responses. Some lactic acid bacteria (LAB), including Lactobacillus, alleviate IBD through immunomodulation. In this study, the anti-colitis effect of LAB isolated from human breast milk was investigated in a mouse model induced acute colitis with 2,4,6-trinitrobenzene sulfonic acid (TNBS). TNBS remarkably increased weight loss, colon shortening, and colonic mucosal proliferation, as well as the expression levels of inflammatory cytokines, including tumor necrosis factor-alpha (TNF-α) and interleukin (IL)-1β. Oral administration of LAB isolated from human breast milk resulted in a reduction in TNBS-induced colon shortening, as well as induced cyclooxygenase (COX)-2, nitric oxide synthase (iNOS), nuclear factor-kappa B (NF-κB). In addition, LAB suppressed inflammatory cytokines such as TNF-α, IL-6, and IL-1β, and thus showed an effect of suppressing the level of inflammation induced by TNBS. Furthermore, LAB alleviated gut microbiota dysbiosis, and inhibited intestinal permeability by increasing the expression of intestinal tight junction protein including ZO-1. Collectively, these results suggest that LAB isolated from human breast milk can be used as a functional food for colitis treatment by regulating NF-κB signaling, gut microbiota and increasing expression of intestinal tight junction protein.

• Journal of Life Science
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• v.25 no.1
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• pp.101-112
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• 2015

A type of cell junction that is formed between different parts within the same cell is called autotypic cell junction. Autotypic junction proteins form tight junctions found between membrane lamellae of a cell, especially in myelinating glial cells. Some of them have postsynaptic density-95/disks large/zonula occludens-1 (PDZ) domains, which interact with the carboxyl (C)-terminal PDZ-binding motif of other proteins. PDZ domains are protein-protein interaction modules that play a role in protein complex assembly. The PDZ domain, which is widespread in bacteria, plants, yeast, metazoans, and Drosophila, allows the assembly of large multi-protein complexes. The multi-protein complexes act in intracellular signal transduction, protein targeting, and membrane polarization. The identified PDZ domain-containing proteins located at autotypic junctions include zonula occludens-1 (ZO-1), ZO-2, pals-1-associated tight junction protein (PATJ), multi-PDZ domain proteins (MUPPs), membrane-associated guanylate kinase inverted 2 (MAGI2), and protease-activated receptor (PAR)-3. PAR-3 interacts with atypical protein kinase C and PAR-6, forming a ternary complex, which plays an important role in the regulation of cell polarity. MAGI2 interacts with ${\alpha}$-amino-3-hydroxyl-5-methyl-4-isoxazole propionate (AMPA) receptor at excitatory synapses. PATJ is detected in paranodal loops associated with claudin-1. On the other hand, MUPP1 is found in mesaxons and Schmidt-Lanterman incisures with claudin-5. ZO-1, ZO-2, and PAR-3 are found at all three sites. Different distributions of PDZ domain-containing proteins affect the development of autotypic junctions. In this review, we will describe PDZ domain-containing proteins at autotypic tight junctions in myelinating Schwann cells and their roles.

• Journal of Microbiology and Biotechnology
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• v.13 no.4
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• pp.495-500
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• 2003

Tight junctions (TJ) between adjacent Sertoli cells in testis are important for the formation of the blood testis barrier (BTB). In an effort to verify the reproductive health risk of endocrine-active chemicals (EACs), changes in the transepithelial electrical resistance (TER) and the expression of TJ genes were examined by co-planar polychlorinated biphenyl (PCB) treatment in cultured mouse Sertoli cells. Although the increase in TER of Sertoli cells was accelerated by 10 nM co-planar PCB, it was downregulated by 100 nM co-planar PCB. The expression of claudin-1 was downregulated by co-planar PCB in a concentration-dependent manner. On the contrary, the expression of claudin-1 was increased in the Sertoli cells by 10 nM co-planar PCB treatment. These results suggest that the structure and function of TJ may be targeted by co-planar PCB in Sertoli cells. Assessment of the structure and function of TJ in Sertoli cells might be useful for screening the reproductive health risk of EACs.

• Food Science of Animal Resources
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• v.42 no.6
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• pp.1046-1060
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• 2022

This study aimed to investigate the effects of the metabolites of Latilactobacillus curvatus BYB3 and indole-activated aryl hydrocarbon receptor (AhR) to increase the tight junction (TJ) proteins in an in vitro model of intestinal inflammation. In a Western blot assay, the metabolites of L. curvatus BYB3 reduced the TJ demage in lipoploysaccharide (LPS) stimulated-Caco-2 cells. This reduction was a result of upregulating the expression of TJ-associated proteins and suppressing the nuclear factor-κB signaling. Immunofluorescence images consistently revealed that LPS disrupted and reduced the expression of TJ proteins, while the metabolites of L. curvatus BYB3 and indole reversed these alterations. The protective effects of L. curvatus BYB3 were observed on the intestinal barrier function when measuring transepithelial electrical resistance. Using high-performance liquid chromatography analysis the metabolites, the indole-3-latic acid and indole-3-acetamide concentrations were found to be 1.73±0.27 mg/L and 0.51±0.39 mg/L, respectively. These findings indicate that the metabolites of L. curvatus BYB3 have increasing mRNA expressions of cytochrome P450 1A1 (CYP1A1) and AhR, and may thus be applicable for therapy of various inflammatory gut diseases as postbiotics.

• The Journal of Pediatrics of Korean Medicine
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• v.37 no.4
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• pp.25-33
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• 2023

Objective This study aimed to confirm the effect of Sabaek-san extract on the recovery of skin damage in atopic dermatitis-induced mice. Methods In this study, we used 4-week-old NC/Nga mice that were assigned to four groups: control (Ctrl), lipid barrier elimination (LBEG), dexamethasone (Dx) administration after lipid barrier elimination (DxAG), and Sabaek-san extract administration after lipid barrier elimination (SBAG). Ten rats were assigned to each treatment group. After drug administration for 3 days following lipid barrier elimination, ceramide kinase, caspase 14, sodium hydrogen antiporter (NHE), cathelicidin, claudin, and Toll-like receptor (TLR2) were observed to confirm restoration of skin moisturizer production, antimicrobial barriers, and tight junctions in the skin barrier. Results Ceramide kinase and caspase 14 positive reactions were significantly higher in the SBAG group than in the LBEG or DxAG groups. NHE and cathelicidin showed a higher positive reaction in the SBAG group than in the LBEG and DxAG groups. Claudins and TLR2 showed a higher positive reaction in the SBAG group than in the LBEG or DxAG groups. Conclusion It was confirmed that Sabaek-san extract may have the potential to restore damaged skin barrier in atopic dermatitis.

• Journal of Microbiology and Biotechnology
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• v.22 no.12
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• pp.1629-1635
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• 2012

Previously, we demonstrated that the erythropoietin receptor (EpoR) is present on fibroblasts, where it regulates focal contact. Here, we assessed whether this action of EpoR is involved in the reduced cell adhesion observed in colonocytes exposed to Clostridium difficile toxin A. EpoR was present and functionally active in cells of the human colonic epithelial cell line HT29 and epithelial cells of human colon tissues. Toxin A significantly decreased activating phosphorylations of EpoR and its downstream signaling molecules JAK-2 (Janus kinase 2) and STAT5 (signal transducer and activator of transcription 5). In vitro kinase assays confirmed that toxin A inhibited JAK 2 kinase activity. Pharmacological inhibition of JAK2 (with AG490) abrogated activating phosphorylations of EpoR and also decreased focal contacts in association with inactivation of paxillin, an essential focal adhesion molecule. In addition, AG490 treatment significantly decreased expression of occludin (a tight junction molecule) and tight junction levels. Taken together, these data suggest that inhibition of JAK2 by toxin A in colonocytes causes inactivation of EpoR, thereby enhancing the inhibition of focal contact formation and loss of tight junctions known to be associated with the enzymatic activity of toxin A.

• Journal of Neurogastroenterology and Motility
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• v.26 no.1
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• pp.106-116
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• 2020

Background/Aims Emerging evidence shows that the mechanism of irritable bowel syndrome (IBS) is associated with neurotrophic factors and tight junction proteins (TJPs). It is known that there are sex differences in the pathophysiology of IBS. The aim of the present study is to determine expression levels of neurotrophic factors, TJPs, and cytokines according to IBS subtype and sex. Methods From 59 IBS (33 IBS-constipation, 21 IBS-diarrhea, and 5 IBS-mixed) and 36 control patients, colonic mucosa mRNA expression levels of transient receptor potential vanilloid-1 (TRPV1), nerve growth factor (NGF), glial cell-derived neurotrophic factor (GDNF), and various TJPs were assessed by real-time polymerase chain reaction. Western blot was performed to determine levels of zonular occludens-1 (ZO-1). Serum levels of cytokines were measured by enzyme-linked immunosorbent assay. Results TRPV1, GDNF, and NGF mRNA levels were significantly increased in those with IBS-constipation compared to those in controls (all P < 0.05). However, they showed no significant difference between those with IBS-diarrhea and controls. Expression level of TRPV1 correlated with that of GDNF (r = 0.741, P < 0.001) and NGF (r = 0.935, P < 0.001). ZO-1 RNA expression levels were lower (P = 0.021) in female IBS-diarrhea than those in controls, although they showed no significant differences between male IBS-diarrhea and controls. Serum IL-1β levels in female IBS were significantly higher than those of male IBS, especially in IBS-constipation (P < 0.001). Conclusion Our results suggest that neurotrophic factors and IL-1β are closely related to IBS-constipation and that decrease of ZO-1 is an important factor in female with IBS-diarrhea.

• Journal of Microbiology and Biotechnology
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• v.28 no.1
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• pp.59-64
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• 2018

Listeria monocytogenes can asymptomatically inhabit the human intestine as a commensal bacterium. However, the mechanism by which L. monocytogenes is able to inhabit the intestine without pathogenic symptoms remains unclear. We compared the invasion efficiency of L. monocytogenes strains with the 268- and 385-bp-long actA gene. Clinical strains SMFM-CI-3 and SMFM-CI-6 with 268-bp actA isolated from patients with listeriosis, and strains SMFM-SI-1 and SMFM-SI-2 with the 385-bp gene isolated from carcasses, were used for inoculum preparation. The invasion efficiency of these strains was evaluated using Caco-2 cells (intestinal epithelial cell line), prepared as normal and healthy cells with tightened tight junctions and senescent cells with loose tight junctions that were loosened by adriamycin treatment. The invasion efficiency of L. monocytogenes strains with the 268-bp-long actA gene was 1.1-2.6-times lower than that of the strains with the 385-bp-long gene in normal and healthy cells. However, the invasion efficiency of both types of strains did not differ in senescent cells. Thus, L. monocytogenes strains with the 268-bp-long actA gene can inhabit the intestine asymptomatically as a commensal bacterium, but they may invade the intestinal epithelial cells and cause listeriosis in senescent cells.

• Journal of Life Science
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• v.20 no.12
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• pp.1784-1791
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• 2010

In this study, we investigated the effects of ethyl alcohol extracts of Hizikia fusiforme (EHF) on the correlation between tightening of tight junctions (TJs) and anti-invasive activity in human gastric adenocarcinoma AGS cells. Inhibitory effects of EHF on cell proliferation, motility, and invasiveness were found to be associated with increased tightness of the TJs, which was demonstrated by an increase in transepithelial electrical resistance. Activities of matrix metalloprotease (MMP)-2 and -9 in AGS cells were dose-dependently inhibited by treatment with EHF, and this was also correlated with a decrease in expression of their mRNA and proteins; however, tissue inhibitor of metalloproteinase (TIMP)-1 and -2 mRNA levels were increased. Additionally, immunoblotting results indicated that EHF repressed the levels of claudin proteins (claudin-1, -3, and -4), major components of TJs that play key roles in control and selectivity of paracellular transport. Furthermore, EHF decreased expression of insulin such as growth factor-1 receptor proteins, while concurrently increasing that of thrombospondin-1 and E-cadherin. In conclusion, these results suggest that EHF treatment may inhibit tumor cell motility and invasion, and therefore act as a dietary source to decrease the risk of cancer metastasis.