• 한국미생물·생명공학회지
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• 제50권1호
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• pp.157-163
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• 2022

Alcoholic liver disease (ALD), which encompasses alcoholic steatosis, alcoholic hepatitis, and alcoholic cirrhosis, is a major cause of morbidity and mortality worldwide. Although the economic and health impacts of ALD are clear, few advances have been made in its prevention or treatment. We recently demonstrated that the insect-derived antimicrobial peptide CopA3 exerts anti-apoptotic and anti-inflammatory activities in various cell systems, including neuronal cells and colonic epithelial cells. Here, we tested whether CopA3 inhibits ethanol-induced liver injury in mice. Mice were intraperitoneally injected with ethanol only or ethanol plus CopA3 for 24 h and then liver injury and inflammatory responses were measured. Ethanol enhanced the production of proinflammatory cytokines, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, interferon (IFN)-γ, and IL-10. It also induced hepatocyte apoptosis and ballooning degeneration in hepatocytes. Notably, all these effects were eliminated or significantly reduced by CopA3 treatment. Collectively, our findings demonstrate that CopA3 ameliorates ethanol-induced liver cell damage and inflammation, suggesting the therapeutic potential of CopA3 for treating ethanol-induced liver injury.

• IMMUNE NETWORK
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• 제13권5호
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• pp.213-217
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• 2013

Enterotoxigenic Bacteroides fragilis (ETBF) is a human gut commensal bacteria that causes inflammatory diarrhea and colitis. ETBF also promotes colorectal tumorigenesis in the Min mouse model. The key virulence factor is a secreted metalloprotease called B. fragilis toxin (BFT). BFT induces E-cadherin cleavage, cell rounding, activation of the ${\beta}$-catenin pathway and secretion of IL-8 in colonic epithelial cells. However, the precise mechanism by which these processes occur and how these processes are interrelated is still unclear. E-cadherin form homophilic interactions which tethers adjacent cells. Loss of E-cadherin results in detachment of adjacent cells. Prior studies have suggested that BFT induces IL-8 expression by inducing E-cadherin cleavage; cells that do not express E-cadherin do not secrete IL-8 in response to BFT. In the current study, we found that HT29/C1cells treated with dilute trypsin solution induced E-cadherin degradation and IL-8 secretion, consistent with the hypothesis that E-cadherin cleavage causes IL-8 secretion. However, physical damage to the cell monolayer did not induce IL-8 secretion. We also show that EDTA-mediated disruption of E-cadherin interactions without E-cadherin degradation was sufficient to induce IL-8 secretion. Finally, we determined that HT29/C1 cells treated with LiCl (${\beta}$-catenin activator) induced IL-8 secretion in a dose-dependent and time-dependent manner. Taken together, our results suggest that BFT induced IL-8 secretion may occur by the following process: E-cadherin cleavage, disruption of cellular interactions, activation of the ${\beta}$-catenin pathway and IL-8 expression. However, we further propose that E-cadherin cleavage per se may not be required for BFT induced IL-8 secretion.

• Journal of Animal Science and Technology
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• 제64권6호
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• pp.1132-1143
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• 2022

Insects are a valuable natural source that can produce a variety of bioactive compounds due to their increasing species diversity. CopA3 is an antimicrobial peptide derived from Copris tripartitus (i.e., the dung beetle). It is known to increase the proliferation of colonic epithelial and neuronal stem cells by regulating cell cycle. This research hypothesized that CopA3 can promote the proliferation of porcine muscle satellite cells (MSCs). The effects of CopA3 on porcine MSCs, which are important for muscle growth and regeneration, remain unclear. Here, we investigated the effects of CopA3 on porcine MSCs. According to viability results, we designed four groups: control (without CopA3) and three treatment groups (treated with 5,10, and 25 ㎍/mL of CopA3). At a CopA3 concentration of 5 ㎍/mL and 10 ㎍/mL, the proliferation of MSCs increased more than that observed in the control group. Furthermore, compared to that in the control, CopA3 treatment increased the S phase but decreased the G0/G1 phase ratio. Additionally, early and late apoptotic cells were found to be decreased in the 5 ㎍/mL group. The expressions of the myogenesis-related transcription factor PAX7 and MYOD proteins were significantly upregulated in the 5 ㎍/mL and 10 ㎍/mL groups, whereas the MYOG protein remained undetected in all group. This study suggested that CopA3 promotes muscle cell proliferation by regulating the cell cycle of MSCs and can regulate the activity of MSCs by increasing the expressions of PAX7 and MYOD.

• Journal of Microbiology and Biotechnology
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• 제22권12호
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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.

• 생명과학회지
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• 제17권1호
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• pp.110-115
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• 2007

Tumor suppressor 유전자로알려진 early growth response gene 1 (EGR-1)에 있어 항산화 천연물인 apigenin과 그대사물인 isovitexin에 의한 장관 상피성 종양세포에 대하여 항종양 역할을 규명하였다. Apigenin 과 isovitexin은 대장암세포에서의 EGR-1 단백질의 발현을 9-12시간의 노출에 의해 농도 의존적으로 증가하였다. 또한 신호전달측면에서 이런 apigenin에 의한 EGR-1 유전자의 유도가 U0126 화합물에 의해 완벽하게 저해 받는 것으로 보아 ERK1/2 MAP kinase pathway의 이 신호전달계에서의 관여를 보여주었다. 본 연구에서 apigenin에 의해 농도 의존적으로 대장암세포의 세포활성의 저해를 MTT assay를 통해 보였고, 또한 EGR-1 siRNA를 transfectien한 세포의 경우 이런 apigenin에 의한 세포활성의 저해효과를 완화하였다. 따라서 apigenin에 의한 항종암세포 세포활성 억제에 있어 EGR-1의 중요성을 보여 준다. 이런 EGR-1에 의해 유도되는 유전자중 대표적으로 NAG-1 유전자의 경우 apigenin과 isovitexin에 의해 24-48시간에 발현이 증가하였다. 결론적으로 암세포 증식억제활성이 있고 apoptosis 유도효과가 있는 NAG-1의 유도에 의해 대장암 세포의 세포활성이 억제된 것으로 의미되고 향후 apigenin 유도의 NAG-1유전자에 의한 암세포증식의 억제기전에 대한 명확한 연구가 요구된다.

• Gut and Liver
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• 제12권6호
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• pp.682-693
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• 2018

Background/Aims: Intestinal barrier dysfunction is a hallmark of inflammatory bowel diseases (IBDs) such as ulcerative colitis. This dysfunction is caused by increased permeability and the loss of tight junctions in intestinal epithelial cells. The aim of this study was to investigate whether estradiol treatment reduces colonic permeability, tight junction disruption, and inflammation in an azoxymethane (AOM)/dextran sodium sulfate (DSS) colon cancer mouse model. Methods: The effects of $17{\beta}$-estradiol (E2) were evaluated in ICR male mice 4 weeks after AOM/DSS treatment. Histological damage was scored by hematoxylin and eosin staining and the levels of the colonic mucosal cytokine myeloperoxidase (MPO) were assessed by enzyme-linked immunosorbent assay (ELISA). To evaluate the effects of E2 on intestinal permeability, tight junctions, and inflammation, we performed quantitative real-time polymerase chain reaction and Western blot analysis. Furthermore, the expression levels of mucin 2 (MUC2) and mucin 4 (MUC4) were measured as target genes for intestinal permeability, whereas zonula occludens 1 (ZO-1), occludin (OCLN), and claudin 4 (CLDN4) served as target genes for the tight junctions. Results: The colitis-mediated induced damage score and MPO activity were reduced by E2 treatment (p<0.05). In addition, the mRNA expression levels of intestinal barrier-related molecules (i.e., MUC2, ZO-1, OCLN, and CLDN4) were decreased by AOM/DSS-treatment; furthermore, this inhibition was rescued by E2 supplementation. The mRNA and protein expression of inflammation-related genes (i.e., KLF4, NF-${\kappa}B$, iNOS, and COX-2) was increased by AOM/DSS-treatment and ameliorated by E2. Conclusions: E2 acts through the estrogen receptor ${\beta}$ signaling pathway to elicit anti-inflammatory effects on intestinal barrier by inducing the expression of MUC2 and tight junction molecules and inhibiting pro-inflammatory cytokines.

• Journal of Microbiology and Biotechnology
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• 제29권11호
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• pp.1729-1738
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• 2019

In sourdough fermentation, lactic acid bacteria perform important roles in the production of volatile and antimicrobial compounds, and exerting health-promoting effects. In this study, we report the probiotic properties and baking characteristics of Lactobacillus plantarum SPC-SNU 72-2 isolated from kimchi. This strain is safe to use in food fermentation as it does not carry genes for biogenic amine production (i.e., hdc, tdc, and ldc) and shows no β-hemolytic activity against red blood cells. The strain is also stable under simulated human gastrointestinal conditions, showing tolerance to gastric acid and bile salt, and adheres well to colonic epithelial cells. Additionally, this strain prevents pathogen growth and activates mouse peritoneal macrophages by inducing cytokines such as tumor necrosis factor-α, interleukin (IL)-6, and IL-12. Furthermore, the strain possesses good baking properties, providing rich aroma during dough fermentation and contributing to the enhancement of bread texture. Taken together, L. plantarum SPC-SNU 72-2 has the properties of a good starter strain based on the observation that it improves bread flavor and texture while also providing probiotic effects comparable with commercial strains.

• 생명과학회지
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• 제28권8호
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• pp.885-891
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• 2018

급성위막성대장염(Pseudomembranous colitis)은 C. difficile 세균이 분비하는 톡신A에 의해 유발되는 것으로 알려져 있다. 톡신A에 의한 점막 상피세포의 장벽기능 감소가 발병 원인으로 알려져 있다. 최근 연구에 의하면 톡신 A는 대장상피세포 속 HDAC-6의 활성을 높여 튜블린의 탈아세틸화를 증가시키는 것으로 알려져 있다. 튜블린 단백질의 탈아세틸화는 미세소관 불 형성을 초래하여 점막 상피세포의 극단적인 세포 형태 변형을 야기하게 되며 결국 상피세포의 고유기능인 장벽 기능이 파괴된다고 알려져 있다. 최근 연구자 등은 potassium acetate가 톡신A에 의한 튜블린 탈아세틸화와 미세소관 불 형성을 회복시켜 장염을 유의하게 억제함을 보고하였다. 따라서 본 연구에서는 아세틸기를 포함하는 또 다른 간단한 화학구조의 초산을 적용하여 톡신A의 세포독성을 억제하는지 확인해보고자 하였다. 인간 대장상피세포에서 초산 자극은 튜블린 단백질의 아세틸화를 유의하게 증가시켰다. 또한 초산은 대장상피세포 속 미세소관 형성과정도 강하게 촉진시킴을 확인하였다. 초산은 톡신A에 의한 튜블린 탈아세틸화와 미세소관 불 형성 그리고 세포독성 모두를 유의하게 회복시켰다. 이상의 결과는 초산에 의한 미세소관 형성 촉진이 톡신A에 의해 초래되는 세포골격계 파괴와 그로 인한 세포독성을 억제할 수 있음을 보여준다. 따라서 초산이 톡신A의 작용을 차단하여 위막성대장염 증상을 완화시킬 수 있는 치료제로서 개발 가치가 있음을 보여준다.

• 한국식품영양과학회지
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• 제34권3호
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• pp.356-360
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• 2005

장의 건강을 유지하기 위해서는 식이섬유, 장내세균총, 소화 상피세포와 점액질층(mucus layer)을 포함하는 점액질(mucosa)의 3대 요소가 상호보완 및 균형 관계가 중요하다. 특히 점액의 분비와 점액층의 형성이 제대로 이루어져야 하며 각종 장질환의 거의 대부분은 뮤신의 부족과 깊은 관계가 있는 보고 자료를 참고하여 식물성 복합추출물인 장기능 개선제 KTG075의 장기능 개선 효과 및 배변촉진 효과를 알아보기 위해 랫드의 대장 내 점액(mucin)의 분비에 미치는 영향을 조사하였다. Loperamide를 투여하여 변비를 유발시킨 랫드에 장기능개선제 KTG075를 투여한 후 대장 내 변의 수를 관찰한 결과, loperamide 단독 처 리군보다 변의 수가 68.2% 감소하는 것이 관찰되었으며, 대장 내 점액질 층의 두께 측정시는 loperamide단독 처리군은 정상 대조군에 비해 랫드의 대장 내에 분비되는 점액질의 두께가 약 31%가 감소하였으나, KTG075 동시 처리군에서는 점액질의 두께가 정상적으로 회복되는 것이 조직검사에서 관찰되었으며, Alcian blue 염색으로 점 액 질 두께 변화 관찰 시는 lopreamide 단독 처리군에서 현저히 감소되었고 KTG075 동시처리군에서는 점액질 층이 거의 정상수준으로 증가되었다. 결과적으로, loperamide 단독처리군에서는 점액질(mucus)의 생성과 분비가 감소되나, 장기능개선제인 KTG075는 장기능을 활성화시킴으로써 점액의 분비를 증가시켜 증가된 점액이 대장 내 윤활제로서 작용하여 장관 운동을 증가시켜 배변을 용이하게 하여 변비 또는 스트레스 등에 의해 저하된 장 기능을 개선시키는 것으로 판단되었다.

• Nutritional Sciences
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• 제5권4호
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• pp.175-183
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• 2002

To compare the effects of various types of dietary fiber on microbial production of short-chain fatty acids (SCFA) and on colon cell proliferation which is used as an intermediate biomarker for colon carcinogenesis, groups of 10 male Sprague-Dawley rats were fed one of four fiber-supplemented diets (6% cellulose, 6% pectin, 6% polydextrose, and a mixture of 3% cellulose and 3% polydextrose) for three weeks. As a control, a fiber-free diet was fed to a separate group of 10 rats. Cell proliferation was measured by in vivo incorporation of bromodeoxyuridine into DNA in the proximal and distal colon, respectively. Luminal concentrations of SCFA were measured by gas chromatography. Dietary fiber significantly influenced microbial production of SCFA in the colon; pectin supplementation produced the highest concentrations of luminal SCFA in both the proximal and distal colon (p<0.05). The degree of individual SCFA production was characterized by a relatively higher increase in butyrate production by the pectin-supplemented diet, and in propionate production by the polydextrose-supplemented diet, resulting in alterations of the molar ratios of acetate, propionate and butyrate. There were significant differences in colon cell proliferation among the diet groups; the pectin-supplemented diet produced a significantly higher effect on cell proliferation of distal colonic epithelial cells (p＜0.05), and the polydextrose-supplemented diet produced an intermediate effect compared to the fiber-free or cellulose-supplemented diet. Increased cell proliferation was correlated to increased luminal concentrations of butyrate in the proximal colon and to increased luminal concentrations of propionate and butyrate in the distal colon (p<0.05). Therefore, these data suggest that dietary fiber may modulate colon cell proliferation by altering luminal SCFA concentrations, particularly butyrate and perhaps propionate. In addition, the present study is the first finding that has demonstrated a relative increase in colon cell proliferation due to supplementation with polydextrose, suggesting that the overuse of this artificially synthesized polysaccharide in food processing technology needs to be carefully evaluated from the public health point of view.