• Journal of Microbiology and Biotechnology
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• 제29권10호
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• pp.1675-1681
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• 2019

Clostridium difficile toxin A is known to cause colonic epithelial cell apoptosis, which is considered the main causative event that triggers inflammatory responses in the colon, reflecting the concept that the essential role of epithelial cells in the colon is to form a physical barrier in the gut. We previously showed that toxin A-induced colonocyte apoptosis and subsequent inflammation were dependent on prostaglandin E2 ($PGE_2$) produced in response to toxin A stimulation. However, the molecular mechanism by which $PGE_2$ mediates cell apoptosis in toxin A-exposed colonocytes has remained unclear. Here, we sought to identify the signaling pathway involved in toxin A-induced, $PGE_2$-mediated colonocyte apoptosis. In non-transformed NCM460 human colonocytes, toxin A exposure strongly upregulated expression of Bak, which is known to form mitochondrial outer membrane pores, resulting in apoptosis. RT-PCR analyses revealed that this increase in Bak expression was attributable to toxin A-induced transcriptional upregulation. We also found that toxin A upregulation of Bak expression was dependent on $PGE_2$ production, and further showed that this effect was recapitulated by an Prostaglandin E2(PGE2) receptor-1 receptor agonist, but not by agonists of other EP receptors. Collectively, these results suggest that toxin A-induced cell apoptosis involves $PGE_2$-upregulation of Bak through the EP1 receptor.

• 대한미세수술학회:학술대회논문집
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• 대한미세수술학회 1996년도 제16차 학술대회
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• pp.183.1-183.1
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• 1996

• 대한약침학회지
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• 제5권2호
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• pp.40-51
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• 2002

Objectives : The purpose of this study was to investigate the effect of Bee Venom on the lipopolysaccharide-induced expression phospholipase $A_2$, cyclooxygenase-2 and inducible nitrogen oxide synthase, and the generation of arachidonic acid, prostaglandin D2 and E2 in RAW 264.7 cells, a murine macrophage cell line. Methods : The expression of phospholipase $A_2$, cyclooxygenase and inducible nitrogen oxide synthase was determined by western blotting with corresponding antibodies, and the generation of arachidonic acid, prostaglandin $D_2$ and $E_2$ was assayed by ELISA method in RAW 264.7 cells. The non-toxic concentrations (0.1 to $5\;{\mu}g/ml$) of bee venom determined by MTT assay, were used in this study. Results : 1. Bee venom inhibited lipopolysaccharide-induced expression of phospholipase $A_2$ in a dose dependent manner after 48 hours treatment. 2. Bee venom inhibited lipopolysaccharide-induced expression of cyclooxygenase-2 in a dose dependent manner after 24 and 48 hours treatment. 3. Bee venom inhibited lipopolysaccharide-induced expression of inducible nitrogen oxidesynthase in a dose dependent manner after 48 hours treatment. 4. The generation of arachidonic acid, prostaglandin $D_2$ and $E_2$ was not much affected by the treatment of bee venom on the lipopolysaccharide-induced generation of arachidonic acid, prostaglandin $D_2$ and $E_2$ in RAW 264.7 cells.

• Korean Journal of Acupuncture
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• 제22권1호
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• pp.85-93
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• 2005

목적 : 본 연구는 봉독 약침액이 BV2 microglial cell에서 LPS로 유발된 염증반응에 대한 억제효과를 관찰하고자 하였다. 방법 : 봉독 약침액의 항염증작용을 관찰하기 위하여 BV2 microglial cell에 봉독약침액을 1시간전에 농도별$(0.1,\;1,\;100\;{\mu}g/ml)$로 전처치한 후 LPS $(5\;{\mu}g/ml)$로 24시간 동안 처리하여 RT-PCR, western blot, $PGE_2$, assay, NO synthesis assay등의 방법으로 관찰하였다. 결과 : LPS 염증유발에 의해서 BV2 microglial cell에서 COX-2 및 NOS 발현이 증가하였고, 이 러한 증가는 prostaglandin E2 및 NO 합성을 증가시켰다. 이에 반하여 봉독약침액으로 전처치한 군에서는 COX-2 및 NOS 발현을 억제시켜 결과적으로 prostaglandin 합성 및 NO 합성을 억제시킴을 확인할 수 있었다. 또한 LPS 염증유발에 의해서 활성화된 NF-kB의 발현을 억제 시켰다. 결론 : 봉독약침 액은 LPS 염증유발에 의해서 증가된 prostaglandin E2 및 NO 합성을 억제시킴으로써 여러 가지 염종질환의 치료에 유효한 효과가 있을 것으로 사려 된다.

• IMMUNE NETWORK
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• 제11권6호
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• pp.364-367
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• 2011

Background: Prostaglandins (PGs) play pathogenic and protective roles in inflammatory diseases. The novel concept of PGs as immune modulators is being documented by several investigators. By establishing an in vitro experimental model containing human follicular dendritic cell-like cells, HK cells, we reported that HK cells produce prostaglandin $E_2$ ($PGE_2$) and prostaglandin $I_2$ ($PGI_2$) and that these PGs regulate biological functions of T and B cells. Methods: To investigate the respective contribution of cyclooxygenase-1 (COX-1) and COX-2 to $PGE_2$ and $PGI_2$ production in HK cells, we performed siRNA technology to knock down COX enzymes and examined the effect on PG production. Results: Both $PGE_2$ and $PGI_2$ productions were almost completely inhibited by the depletion of COX-2. In contrast, COX-1 knockdown did not significantly affect PG production induced by lipopolysaccharide (LPS). Conclusion: The current results suggest that mPGES-1 and PGIS are coupled with COX-2 but not with COX-1 in human follicular dendritic cell (FDC) and may help understand the potential effects of selective COX inhibitors on the humoral immunity.

• Journal of Pharmaceutical Investigation
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• 제29권2호
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• pp.111-115
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• 1999

We have studied the transdermal flux of prostaglandin $E_1$ $(PGE_1)$ from a hydrogel patch through hairless mouse skin, to test the possibility of developing a transdermal delivery system. Karaya gum patch containing $PGE_1$ was prepared by casting method. $PGE_1$ was stable in the patch for 10 weeks. The effect of current application, enhancer (propylene glycol monolaurate : PGML), adhesive and patch thickness on the flux was studied using side-by-side diffusion cell. Passive flux of $PGE_1$ was negligible. Cathodal delivery increased the flux about 20 fold. As the concentrations of PGML increased, flux increased. When 5% PGML was used as the enhancer, maximum flux by cathodal iontophoresis was $55\;{\mu}g/cm^2\;hr$. It increased about 2 folds to $100\;{\mu}g/cm^2\;hr$, when the amount of PGML used was 9%. Large increase in flux and the decrease in time to reach maximum flux were observed when the skin was pretreated with neat PGML (maximum flux obtained was about $200\;{\mu}g/cm^2\;hr$). Use of adhesive decreased the flux significantly. To the contrary of our expectation, increase in current density decreased the flux. These flux data together with the stability data indicate that, though the onset of sufficient delivery occur after 1-2 hours of application, therapeutic amount of $PGE_1$ can be delivered through skin using iontophoresis and penetration enhancer.

• 대한약리학회지
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• 제25권1호
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• pp.93-99
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• 1989

본 교실의 연구결과에 의하면 토끼와 흰쥐에서 수정란 착상시기에 peripheral lymphocyte와 thymocyte의 활성도가 저하될 뿐만 아니라 착상기간중 생성되는 prostaglandin E(PGE)의 생리적인 농도로도 peripheral lymphocyte와 thymocyte의 활성도가 억제되었다. 그러므로 본 연구에서는 흰쥐의 착상시기에 전신적인 면역기능 뿐만 아니라 국소적으로 DLN lymphocyte의 활성도가 억제되는지를 관찰하고 PGE가 어떠한 기전으로 모체의 면역기능을 억제하는가를 관찰하여 다음과 같은 결과를 얻었다. 1. 흰쥐의 착상시기에 DLN lymphocyte의 활성도가 임신하기 않은 흰쥐의 DLN lymphocyte에 비하여 통계적으로 유의하지는 않으나 저하되었으며 이러한 저하현상은 100% 흰쥐에서 관찰되었다. 2. 착상시기의 DLN lymphocyte에 prostaglandin 합성억제제인 indomethacin(ID)를 처리하면 DLN lymphocyte의 활성도가 통계적으로 유의하게 증가하였다. 그러나 임신하지 않은 흰쥐의 DLN lymphocyte의 활성도는 증가되어 있으나 $PGE_2$를 전처리하면 DLN lymphocyte의 활성도가 유의하게 억제되며 $PGE_2$를 전처치한 후 ID를 처리하면 DLN lymphocyte의 활성도가 $PGE_2$로 전처치하지 않고 ID를 처리한 경우에 비하여 유의하게 증가하였다. 그러나 $PGE_2$ 대신estradiol, progesterone 및 hCG를 전처치하였을 경우에는 ID 처리로 DLN lymphocyte의 활성도가 증가하지 않았다. 3. 임신하지 많은 흰쥐의 DLN lymphocyte에 $PGE_2$를 전처리하면 PGE-producing cell이 유도되어 PGE 생성이 증가하는지를 확인하기 위하여 $PGE_2$를 전처리하고 Con A를 처리한 후 배양액의 PGE를 정량한 결과 PGE를 전처리하지 않은 DLN lymphocyte에 비하여 유의하게 PGE 생성이 증가하였다. 이상의 결과로 보아 흰쥐의 착상시기에는 모체의 DLN lymphocyte의 활성도가 저하되며, 특히 PCE는 PGE-producing cell을 유도함으로써 착상시기의 모체의 면역기능에 영향을 주는 것으로 생각된다.

• Biomolecules & Therapeutics
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• 제18권4호
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• pp.402-410
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• 2010

Although the overproduction of prostaglandin $E_2$ ($PGE_2$) in intestinal epithelial cells has been considered to be highly correlated with the colorectal carcinogenesis, the precise mechanism of action remains poorly elucidated. Accumulating evidence suggests that the PGE receptor (EP)-mediated signal transduction pathway might play an important role in this process. In the present study, we investigated the mechanism of action underlying $PGE_2$-mediated cell proliferation and the effect of resveratrol on the proliferation of human colon cancer cells in terms of the modulating $PGE_2$-mediated signaling pathway. $PGE_2$ stimulated the proliferation of several human colon cancer cells and activated growth-stimulatory signal transduction, including Akt and ERK. $PGE_2$ also increased the phosphorylation of GSK-$3{\beta}$, the translocation of ${\beta}$-catenin into the nucleus, and the expressions of c-myc and cyclin D1. Resveratrol, a cancer chemopreventive phytochemical, however, inhibited $PGE_2$-induced growth stimulation and also suppressed $PGE_2$-mediated signal transduction, as well as ${\beta}$-catenin/T cell factor-mediated transcription in human colon cancer cells. These findings present an additional mechanism through which resveratrol affects the regulation of human colon cancer cell growth.

• International Journal of Oral Biology
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• 제42권4호
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• pp.149-153
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• 2017

Cyclooxygenase-2 (COX-2)-mediated prostaglandin $E_2$ ($PGE_2$) plays a key role in development and progression of inflammatory responses and Porphyromonas gingivalis is a common endodontic pathogen. In this study, we investigated induction of COX-2 and $PGE_2$ by P. gingivalis in human dental pulp cells (HDPCs). P. gingivalis increased expression of COX-2, but not that of COX-1. Increased levels of $PGE_2$ were released from P. gingivalis-infected HDPCs and this $PGE_2$ increase was blocked by celecoxib, a selective COX-2 inhibitor. P. gingivalis activated all three types of mitogen-activated protein kinases (MAPKs). P. gingivalis-induced activation of nuclear $factor-{\kappa}B$ ($NF-{\kappa}B$) was demonstrated by the results of phosphorylation of $NF-{\kappa}B$ p65 and degradation of inhibitor of ${\kappa}B-{\alpha}$ ($I{\kappa}B-{\alpha}$). Pharmacological inhibition of each of the three types of MAPKs and $NF-{\kappa}B$ substantially attenuated P. gingivalis-induced $PGE_2$ production. These results suggest that P. gingivalis should promote endodontic inflammation by stimulating dental pulp cells to produce $PGE_2$.

• 동의생리병리학회지
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• 제20권5호
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• pp.1295-1302
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• 2006

Our preliminary aim is to elucidate the pharmacokinetic features of the PNS(Panax notoginseng Buck F.H. Chen. (Arialiaceae) root). First, we assessed the prevention of neurtrophil functions. A Panax notoginseng inhibited neutrophil functions, including degranulation, superoxide generation, and leukotriene B4 production, without any effect on 5-lipoxygenase activity. This Panax notoginseng reduced nitric oxide (NO) and prostaglandin E2 production in mouse peritoneal macrophages stimulated with lipopolysaccharide, whereas no influence on the activity of inducible NO synthase, cyclo-oxygenase-2 or cyclo-oxygenase-1 was observed. Panax notoginseng significantly reduced mouse paw oedema induced by carrageenan. The results indicate that Panax notoginseng exerts anti-inflammatory effects related to the inhibition of neutrophil functions and of NO and prostaglandin E2 production, which could be due to a decreased expression of inducible NO synthase and cyclo-oxygenase-2.