• Nutrition Research and Practice
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• 제13권2호
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• pp.95-104
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• 2019

BACKGROUND/OBJECTIVES: Inflammatory Bowel Disease (IBD) has rapidly escalated in Asia (including Korea) due to increasing westernized diet patterns subsequent to industrialization. Factors associated with endoplasmic reticulum (ER) stress are demonstrated to be one of the major causes of IBD. This study was conducted to investigate the effect of Lycium barbarum (L. barbarum) on ER stress. MATERIALS/METHODS: Mouse embryonic fibroblast (MEF) cell line and polarized Caco-2 human intestinal epithelial cells were treated with crude extract of the L. chinense fruit (LF). Paracellular permeability was measured to examine the effect of tight junction (TJ) integrity. The regulatory pathways of ER stress were evaluated in MEF knockout (KO) cell lines by qPCR for interleukin (IL) 6, IL8 and XBP1 spliced form (XBP1s). Immunoglobulin binding protein (BiP), XBP1s and CCAAT/enhancer-binding homologous protein (CHOP) expressions were measured by RT-PCR. Scanning Ion Conductance Microscopy (SICM) at high resolution was applied to observe morphological changes after treatments. RESULTS: Exposure to LF extract strengthened the TJ, both in the presence and absence of inflammation. In polarized Caco-2 pretreated with LF, induction in the expression of proinflammatory marker IL8 was not significant, whereas ER stress marker XBP1s expression was significantly increased. In wild type (wt) MEF cells, IL6, CHOP and XBP1 spliced form were dose-dependently induced when exposed to $12.5-50{\mu}g/mL$ extract. However, absence of XBP1 or $IRE1{\alpha}$ in MEF cells abolished this effect. CONCLUSION: Results of this study show that LF treatment enhances the barrier function and reduces inflammation and ER stress in an $IRE1{\alpha}$-XBP1-dependent manner. These results suggest the preventive effect of LF on healthy intestine, and the possibility of reducing the degree of inflammatory symptoms in IBD patients.

• 대한한의학방제학회지
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• 제26권4호
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• pp.307-318
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• 2018

Objectives : Endoplasmic reticulum (ER) stress designates cellular responses to the accumulation of misfolded and unfolded proteins in ER, which is related to a variety of liver diseases. Present study investigated the inhibitory effects of Litsea japonica flesh water extract (LJE) aganist ER stress. Methods : After HepG2 cells were pretreated with LJE and subsequently exposed to tunicamycin (Tm) or thapsigargin (Tg), expression of C/EBP homologous protein (CHOP), glucose regulated protein 78 kDa (GRP78), asparagine synthetase (ASNS), and endoplasmic reticulum DnaJ homologue 4 (ERDJ4) were determined by immunoblot and real-time PCR analysis. Three canonical signaling pathways in response to ER stress were examined to explore molecular mechanisms involved. Results : Pretreatment of 1 mg/mL LJE inhibited Tm- or Tg-induced CHOP expression, while L. japonica fruit water extract did not. In addition, LJE decreased the levels of GRP78, ASNS, and ERDJ4 mRNA by Tm. Moreover, phosphorylations of eukaryotic translation initiation factor $2{\alpha}$ and inositol-requiring enzyme 1, expression of nuclear form of activating transcription factor $6{\alpha}$, and transactivation of ER stress response element- and unfolded protein response element-harboring luciferase activities were inhibited by LJE pretreatment. Conclusions : Present results suggest that LJE would be a candidate to prevent or treat ER stress-mediated liver injuries.

• BMB Reports
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• 제54권2호
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• pp.124-129
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• 2021

In current times, obesity is a major health problem closely associated with metabolic disease such as diabetes, dyslipidemia, and cardiovascular disease. The direct cause of obesity is known as an abnormal increase in fat cell size and the adipocyte pool. Hyperplasia, the increase in number of adipocytes, results from adipogenesis in which preadipocytes differentiate into mature adipocytes. Adipogenesis is regulated by local and systemic cues that alter transduction pathways and subsequent control of adipogenic transcription factors. Therefore, the regulation of adipogenesis is an important target for preventing obesity. Myonectin, a member of the CTRP family, is a type of myokine released by skeletal muscle cells. Although several studies have shown that myonectin is associated with lipid metabolism, the role of myonectin during adipogenesis is not known. Here, we demonstrate the role of myonectin during adipocyte differentiation of 3T3-L1 cells. We found that myonectin inhibits the adipogenesis of 3T3-L1 preadipocytes with a reduction in the expression of adipogenic transcription factors such as C/EBPα, β and PPARγ. Furthermore, we show that myonectin has an inhibitory effect on adipogenesis through the regulation of the p38 MAPK pathway and CHOP. These findings suggest that myonectin may be a novel therapeutic target for the prevention of obesity.

• Biomolecules & Therapeutics
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• 제30권3호
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• pp.265-273
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• 2022

Resistance to chemotherapeutic drugs is a significant problem in the treatment of colorectal cancer, resulting in low response rates and decreased survival. Recent studies have shown that shikonin, a naphthoquinone derivative, promotes apoptosis in colon cancer cells and cisplatin-resistant ovarian cells, raising the possibility that this compound may be effective in drug-resistant colorectal cancer. The aim of this study was to characterize the molecular mechanisms underpinning shikonin-induced apoptosis, with a focus on endoplasmic reticulum (ER) stress, in a 5-fluorouracil-resistant colorectal cancer cell line, SNU-C5/5-FUR. Our results showed that shikonin significantly increased the proportion of sub-G₁ cells and DNA fragmentation and that shikonin-induced apoptosis is mediated by mitochondrial Ca²⁺ accumulation. Shikonin treatment also increased the expression of ER-related proteins, such as glucose regulatory protein 78 (GRP78), phospho-protein kinase RNA-like ER kinase (PERK), phospho-eukaryotic initiation factor 2 (eIF2α), phospho-phosphoinositol-requiring protein-1 (IRE1), spliced X-box-binding protein-1 (XBP-1), cleaved caspase-12, and C/EBP-homologous protein (CHOP). In addition, siRNA-mediated knockdown of CHOP attenuated shikonin-induced apoptosis, as did the ER stress inhibitor TUDCA. These data suggest that ER stress is a key factor mediating the cytotoxic effect of shikonin in SNU-C5/5-FUR cells. Our findings provide an evidence for a mechanism in which ER stress leads to apoptosis in shikonin-treated SNU-C5/5-FUR cells. Our study provides evidence to support further investigations on shikonin as a therapeutic option for 5-fluorouracil-resistant colorectal cancer.

• Radiation Oncology Journal
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• 제22권3호
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• pp.177-183
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• 2004

목적: 초기 병기 비강 natural killer/T-ceil 림프종에 대한 CHOP 항암화학요법과 국소 방사선치료의 순차적 적용 결과를 보고하고자 한다. 대상 및 방법: 1995년 3월부터 1999년 12월 사이에 성균관의대 삼성서울병원 종양센타에 비강 I/II 병기natural killer/T-cell 림프종으로 등록된 17명의 환자들 중 14명의 환자들에 대하여 순차적 항암화학요법과 방사선치료를 적용하였고 이들에 대한 분석을 시행하였다. 치료방침은 우선 CHOP 항암화학요법을 3주 간격으로 3~4회 시행한 후 5주간에 걸쳐 육안적 병변과 인접한 림프절 부위에 대한 국소 방사선치료를 추가하는 것이었다. 결과: 방사선치료의 시작 전에 시행한 국소종양의 항암화학요법에 대한 반응평가는 50%의 환자들에서 양호한 반응(완전관해 5명+부분관해 2명)을 보였고 나머지 50%의 환자들에서는 병변이 진행하였다. 5명의 환자에서 국소재발이 나타났는데 이들 중 2명은 원격전이를 동반하였고, 영역 림프절 재발을 수반한 경우는 없었다. 3년 생존율과 무병생존율은 50.0%와 42.9%였으며, 모든 사망과 재발사례는 치료개시 후 13개월 이내에 발생하였다. 예후인자의 단변량 분석에서 'B' 증상이 없는 경우, 항암화학요법과 전체 치료방침에 양호한 반응을 보인 경우, 국제예후지표상 저위험군 등이 양호한 생존율과 관련이 있었다. 결론: 본 연구의 치료방침에 의한 결과는 과거의 방사선치료 단독 또는 방사선치료 후 항암화학요법 추가에 따르는 결과들과 비교해 볼 때 재발양상과 생존율의 측면에서 유리한 점이 없었다. 따라서 방사선치료와 항암화학요법을 새로운 병용방법에 관한 연구개발이 요망된다.

• 대한의생명과학회지
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• 제14권1호
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• pp.59-62
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• 2008

This experiment was performed to study the effect of TSH (thyroid-stimulating hormone) on the expression of endoplasmic reticulum (ER) chaperones in the rat thyrocytes FRTL-5 cells. Although the expressions of ER membrane kinases (ATF6, IRE1 and PERK) were specially enhanced under absence of TSH, no remarkable up- or down regulations of ER chaperones (BiP, CHOP and Calnexin) were detected by TSH. We firstly report here that TSH by dose up-regulated expression of ER membrane kinases in FRTL-5 culture thyrocytes.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 A
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• pp.3-5
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• 1994

The SRM can be operated on the high speed range in which the back-emf is greater than the DC link voltage. However, the phase current of the SRM should be controlled through the selection of an exciting angle since it can not be controlled by a chop of the DC link voltage in the high speed range. In this paper, a PI and a bang-bang controller are employed in order to control the speed of the SRM and the leading angle of the SRM is adapted as a control input. The performances of two controllers are evaluated by computer simulation. The results show that the bang-bang controller is more attractive than the PI controller in the cost and performance aspects.

• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2006년도 제47회 학술심포지움 및 추계국제학술대회
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• pp.103.1-103.1
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• 2006

• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2008년도 제49회 학술심포지움 및 국제학술대회
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• pp.86.2-86.2
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• 2008

• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2007년도 제48회 학술심포지움 및 추계국제학술대회
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• pp.84.1-84.1
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• 2007

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