• Journal of Animal Science and Technology
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• 제64권5호
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• pp.842-853
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• 2022

Ochratoxin A (OTA) is a well-known mycotoxin that causes disease through the ingestion of contaminated food or feed, for example, in the porcine industry. The intestinal epithelium acts as the first barrier against food contamination. We conducted a study on the exposure of the porcine intestinal epithelium to OTA. We used the intestinal porcine epithelial cell line IPEC-J2 as an in vitro model to evaluate the altered molecular mechanisms following OTA exposure. Gene expression profiling revealed that OTA upregulated 782 genes and downregulated 896, totalling 1678 differentially expressed genes. Furthermore, immunofluorescence, quantitative real-time polymerase chain reaction, and western blotting confirmed that OTA damages the tight junction protein ZO-1. Moreover, OTA activated the expression of inflammatory genes (IL-6, IL-8, IL-10, NF-kB, TLR4, and TNF-α). In summary, this study confirmed that OTA alters various molecular mechanisms and has several adverse effects on IPEC-J2 cells.

• 생명과학회지
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• 제26권9호
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• pp.1082-1087
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• 2016

본 연구에서는 염증성 사이토카인 IL-1α가 소장의 tight junction (TJ)의 integrity에 미치는 영향을 평가하고 항염증 효능이 있다고 알려진 curcumin (CCM)이 IL-1α에 의한 TJ 손상 예방효과를 알아보고자 Caco-2 세포 모델을 이용하여 실험하였다. Caco-2 세포 단층의 TJ integrity에 대한 IL-1α의 영향을 FITC-dextran flux와 transepithelial electrical resistance (TEER)를 측정하여 검증하였다. IL-1α를 100 ng/ml의 농도로 Caco-2 세포 단층의 상부에 24시간 동안 처리하였을 때 처리 2시간 이후 FITC-dextran의 flux가 유의적으로 증가하였고, IL-1α 처리시간에 비례하여 상승하였다. 또한 IL-1α의 처리는 TEER 값을 유의적으로 감소시켜 IL-1α에 의한 TJ 손상을 확인할 수 있었다. 반면 CCM의 전처리는 이러한 IL-1α에 의한 TJ 기능 저하를 거의 완전히 예방하는 것을 알 수 있었다. 이상의 결과로 염증성 사이토카인 IL-1α이 TJ의 integrity 조절에 부정적인 영향을 미치며 이는 강황에서 발견되는 CCM 전처리에 의해 효과적으로 억제될 수 있음을 보여준다. 본 연구 결과와 관련되어 TJ 구성단백질 발현 및 작용 기작에 대한 분자세포생물학적 연구와 in vivo 연구가 필요하다.

• Biomolecules & Therapeutics
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• 제29권2호
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• pp.175-183
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• 2021

The mitogen-activated protein kinase (MAPK) pathway controls intestinal epithelial barrier permeability by regulating tight junctions (TJs) and epithelial cells damage. Heme oxygenase-1 (HO-1) and carbon monoxide (CO) protect the intestinal epithelial barrier function, but the molecular mechanism is not yet clarified. MAPK activation and barrier permeability were studied using monolayers of Caco-2 cells treated with tissue necrosis factor α (TNF-α) transfected with FUGW-HO-1 or pLKO.1-sh-HO-1 plasmid. Intestinal mucosal barrier permeability and MAPK activation were also investigated using carbon tetrachloride (CCl4) administration with CoPP (a HO-1 inducer), ZnPP (a HO-1 inhibitor), CO releasing molecule 2 (CORM-2), or inactived-CORM-2-treated wild-type mice and mice with HO-1 deficiency in intestinal epithelial cells. TNF-α increased epithelial TJ disruption and cleaved caspase-3 expression, induced ERK, p38, and JNK phosphorylation. In addition, HO-1 blocked TNF-α-induced increase in epithelial TJs disruption, cleaved caspase-3 expression, as well as ERK, p38, and JNK phosphorylation in an HO-1-dependent manner. CoPP and CORM-2 directly ameliorated intestinal mucosal injury, attenuated TJ disruption and cleaved caspase-3 expression, and inhibited epithelial ERK, p38, and JNK phosphorylation after chronic CCl4 injection. Conversely, ZnPP completely reversed these effects. Furthermore, mice with intestinal epithelial HO-1 deficient exhibited a robust increase in mucosal TJs disruption, cleaved caspase-3 expression, and MAPKs activation as compared to the control group mice. These data demonstrated that HO-1-dependent MAPK signaling inhibition preserves the intestinal mucosal barrier integrity by abrogating TJ dysregulation and epithelial cell damage. The differential targeting of gut HO-1-MAPK axis leads to improved intestinal disease therapy.

• 한국식품과학회지
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• 제42권3호
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• pp.335-342
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• 2010

본 연구에서는 홍삼성분에 의한 장상피세포 간극(tight junction)의 안정화에 대해서 조사하였다. Transwell에 배양한 Caco-2 단세포층을 HBSS로 치환한 후 단세포층의 상층부에 홍삼추출물을 처리하고 96시간동안 배양하면서 TEER(transepithelial electrical resistance)수치의 변화를 조사하였다. 홍삼 추출물을 $20\;{\mu}g/mL$ 이하의 농도로 상층부에 첨가하였을 때에는 시간이 지남에 따라 점차 감소하는 대조구와는 달리 TEER수치가 덜 감소하였다. 한편 $130\;{\mu}g/mL$ 이상의 농도로 처리하였을 때는 TEER수치가 현저히 감소하였으나 MTT assay 결과 세포독성에 의한 것은 아니었다. 인삼으로부터 분리한 저분자물질, 다당류, 단백질, 사포닌, 폴리페놀 조획분을 각각 상층부에 첨가하였을 때, 장상피세포 간극의 안정화 활성을 나타내는 성분은 폴리페놀 및 사포닌 조획분이었으며, 전자는 높은 활성을 후자는 낮은 활성을 나타내었다. 이처럼 홍삼추출물의 폴리페놀 조획분과 사포닌 조획분은 장상피세포의 간극을 안정화시킴으로서, 식품 알레르겐의 체내유입을 차단하여 알레르기억제에 기여할 수 있을 것으로 추측된다.

• Asian-Australasian Journal of Animal Sciences
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• 제27권4호
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• pp.580-586
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• 2014

Intestinal epithelial cells (IECs) forming the barrier for the first-line of protection are interconnected by tight junction (TJ) proteins. TJ alteration results in impaired barrier function, which causes potentially excessive inflammation leading to intestinal disorders. It has been suggested that toll-like receptor (TLR) 2 ligands and some bacteria enhance epithelial barrier function in humans and mice. However, no such study has yet to be claimed in swine. The aim of the present study was to examine whether Bacillus subtilis could improve barrier integrity and protection against deoxynivalenol (DON)-induced barrier disruption in porcine intestinal epithelial cell line (IPEC-J2). We found that B. subtilis decreased permeability of TJ and improved the expression of zonula occludens (ZO)-1 and occludin during the process of forming TJ. In addition, ZO-1 expression of IPEC-J2 cells treated with B. subtilis was up-regulated against DON-induced damage. In conclusion, B. subtilis may have potential to enhance epithelial barrier function and to prevent the cells from DON-induced barrier dysfunction.

• Asian-Australasian Journal of Animal Sciences
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• 제27권5호
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• pp.733-742
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• 2014

The glucagon-like peptide 2 (GLP-2) that is expressed in intestine epithelial cells of mammals, is important for intestinal barrier function and regulation of tight junction (TJ) proteins. However, there is little known about the intracellular mechanisms of GLP-2 in the regulation of TJ proteins in piglets' intestinal epithelial cells. The purpose of this study is to test the hypothesis that GLP-2 regulates the expressions of TJ proteins in the mitogen-activated protein kinase (MAPK) signaling pathway in piglets' intestinal epithelial cells. The jejunal tissues were cultured in a Dulbecco's modified Eagle's medium/high glucose medium containing supplemental 0 to 100 nmol/L GLP-2. At 72 h after the treatment with the appropriate concentrations of GLP-2, the mRNA and protein expressions of zonula occludens-1 (ZO-1), occludin and claudin-1 were increased (p<0.05). U0126, an MAPK kinase inhibitor, prevented the mRNA and protein expressions of ZO-1, occludin, claudin-1 increase induced by GLP-2 (p<0.05). In conclusion, these results indicated that GLP-2 could improve the expression of TJ proteins in weaned pigs' jejunal epithelium, and the underlying mechanism may due to the MAPK signaling pathway.

• The Korean Journal of Physiology and Pharmacology
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• 제20권2호
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• pp.147-152
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• 2016

Present study aimed to investigate the effect of curcumin-pretreatment on intestinal I/R injury and on intestinal mucosa barrier. Thirty Wistar rats were randomly divided into: sham, I/R, and curcumin groups (n=10). Animals in curcumin group were pretreated with curcumin by gastric gavage (200 mg/kg) for 2 days before I/R. Small intestine tissues were prepared for Haematoxylin & Eosin (H&E) staining. Serum diamine oxidase (DAO) and tumor necrosis factor (TNF)-${\alpha}$ levels were measured. Expression of intestinal TNF-${\alpha}$ and tight junction protein (ZO-1) proteins was detected by Western blot and/or immunohistochemistry. Serum DAO level and serum and intestinal TNF-${\alpha}$ leves were significantly increased after I/R, and the values were markedly reduced by curcumin pretreatment although still higher than that of sham group (p<0.05 or p<0.001). H&E staining showed the significant injury to intestinal mucosa following I/R, and curcumin pretreatment significantly improved the histological structure of intestinal mucosa. I/R insult also induced significantly down-regulated expression of ZO-1, and the effect was dramatically attenuated by curcumin-pretreatment. Curcumin may protect the intestine from I/R injury through restoration of the epithelial structure, promotion of the recovery of intestinal permeability, as well as enhancement of ZO-1 protein expression, and this effect may be partly attributed to the TNF-${\alpha}$ related pathway.

• Journal of Ginseng Research
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• 제42권1호
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• pp.50-56
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• 2018

Background: Saponins from Panax japonicus (SPJ) are the most abundant and main active components of P. japonicus, which replaces ginseng roots in treatment for many kinds of diseases in the minority ethnic group in China. Our previous studies have demonstrated that SPJ has the effects of anti-inflammation through the mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-${\kappa}B$) signaling pathways. The present study was designed to investigate whether SPJ can modulate intestinal tight junction barrier in aging rats and further to explore the potential mechanism. Methods: Aging rats had been treated with different doses (10 mg/kg, 30 mg/kg, and 60 mg/kg) of SPJ for 6 mo since they were 18 mo old. After the rats were euthanized, the colonic samples were harvested. Levels of tight junctions (claudin-1 and occludin) were determined by immunohistochemical staining. Levels of proinflammatory cytokines (interleukin-$1{\beta}$ and tumor necrosis factor-${\alpha}$) were examined by Western blot. NF-${\kappa}B$ and phosphorylation of MAPK signaling pathways were also determined by Western blot. Results: We found that SPJ increased the expression of the tight junction proteins claudin-1 and occludin in the colon of aging rats. Treatment with SPJ decreased the levels of interleukin-$1{\beta}$ and tumor necrosis factor-${\alpha}$, reduced the phosphorylation of three MAPK isoforms, and inhibited the expression of NF-${\kappa}B$ in the colon of aging rats. Conclusion: The studies demonstrated that SPJ modulates the damage of intestinal epithelial tight junction in aging rats, inhibits inflammation, and downregulates the phosphorylation of the MAPK and $NF-{\kappa}B$ signaling pathways.

• 한국식품영양과학회지
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• 제41권7호
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• pp.881-887
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• 2012

유산균과 금은화, 발효 금은화는 장누수 증후군과 연관된 장 상피세포 점막 투과성 감소에 대하여 유의한 효과를 나타내었다. 따라서 유산균을 단독으로 사용하는 방법과 유산균을 이용해 발효시킨 금은화를 증가된 장 투과성 및 장내미생물 불균형으로 인한 장누수 증후군과 관련된 일련의 증상들을 치료하고 면역관련 질환 및 만성 염증성 질환에도 응용할 수 있을 것으로 예상되며 이에 대한 앞으로의 추가 연구가 필요할 것으로 사료된다.

• 대한수의학회지
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• 제56권2호
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• pp.57-66
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• 2016

The gut epithelial barrier, which is composed of the mucosal layer and the intestinal epithelium, has multiple defense mechanisms and interconnected regulatory mechanisms against enteric microbial pathogens. However, many bacterial pathogens have highly evolved infectious stratagems that manipulate mucin production, epithelial cell-cell junctions, cell death, and cell turnover to promote their replication and pathogenicity in the gut epithelial barrier. In this review, we focus on current knowledge about how bacterial pathogens regulate mucin levels to circumvent the epithelial mucus barrier and target cell-cell junctions to invade deeper tissues and increase their colonization. We also describe how bacterial pathogens manipulate various modes of epithelial cell death to facilitate bacterial dissemination and virulence effects. Finally, we discuss recent investigating how bacterial pathogens regulate epithelial cell turnover and intestinal stem cell populations to modulate intestinal epithelium homeostasis.