• ALGAE
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• 제29권4호
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• pp.343-353
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• 2014

Despite the extensive literature on marine algae over the past few decades, a paucity of published research and studies exists on red algae. The purpose of this study was to evaluate the potential therapeutic properties of the ethanol extract of the red alga Callophyllis japonica against lipopolysaccharide (LPS)-stimulated macrophage inflammation. The C. japonica extract (CJE) significantly inhibited the nitric oxide (NO) production and the induced dose-dependent reduction of the protein and mRNA levels of inducible nitric oxide synthase and cyclooxygenase-2. Additionally, the CJE reduced the mRNA levels of inflammatory cytokines, including tumor necrosis factor-${\alpha}$, interleukin (IL)-$1{\beta}$, and IL-6. We investigated the mechanism by which the CJE inhibits NO by examining the level of mitogen-activated protein kinases (MAPKs) activation, which is an inflammation-induced signaling pathway in macrophages. The CJE significantly suppressed the LPS-induced phosphorylation of c-Jun N-terminal kinase, extracellular signal-regulated kinase and p38 MAPK. Taken together, the results of this study demonstrate that the CJE inhibits LPS-induced inflammation by blocking the MAPK pathway in macrophages.

• 한국콘텐츠학회논문지
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• 제9권4호
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• pp.355-363
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• 2009

비정상적인 미토콘드리아에 의해 산화 스트레스가 증가하면 세포내 신호전달 및 유전자 발현에 손상을 일으켜 인슐린 저항성이나 당뇨병 등의 여러 질환들을 유발한다. 그런데 자식작용은 산화 스트레스로 기능이 저하된 미토콘드리아를 제거하여 인슐린 저항성 등을 억제해준다. 한편 운동도 미토콘드리아 생합성을 강화시켜 조직의 기능저하나 퇴행을 회복시켜준다. 따라서 운동과 자식작용이 서로 연관되어 미토콘드리아 생합성을 유도하는 신호체계로 작용할 가능성이 있고, 이 연구를 통해 운동 혹은 AICAR (aminoimidazole-4-carboxamide-1-${\beta}$-D-ribofuranoside)처치로 활성 화된 AMPK(5'-AMP- activated protein kinase) 신호전달체계가 미토콘드리아 생합성을 증가시키는 경로에 자식작용이 관여하는지의 여부를 확인하고자 하였다. 연구결과에 따르면, 6시간의 급성운동으로 쥐의 골격근에서 PGC-1(peroxisome proliferator-activated receptor gamma coactivator 1)과 mtTFA (mitochondrial transcription factor A)의 mRNA 발현이 유의하게 증가하였다. 하지만 자식작용 표지제인 LC3(microtubule-associated proteinl light chain 3)의 mRNA 발현은 증가경향을 나타냈지만 유의하지 않았다. 한편 C2C12 근세포에서도 AICAR 처치에 의해 PGC-1, mtTFA mRNA 발현이 모두 증가하였지만, 이러한 증가는 LC3 SiRNA에 의해서 억제되지 않는 것으로 나타났다. 이러한 결과들을 통해 자식작용은 AMPK에 의해 조절되는 신호전달 전달체계와는 다른 경로로 미토콘드리아 생합성에 영향을 미칠 것으로 사료된다.

• Journal of Microbiology and Biotechnology
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• 제28권9호
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• pp.1554-1562
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• 2018

The type I interferons (IFNs) play a vital role in activation of innate immunity in response to viral infection. Accordingly, viruses have evolved to employ various survival strategies to evade innate immune responses induced by type I IFNs. For example, hepatitis E virus (HEV) encoded papain-like cysteine protease (PCP) has been shown to inhibit IFN activation signaling by suppressing K63-linked de-ubiquitination of retinoic acid-inducible gene I (RIG-I) and TANK-binding kinase 1 (TBK1), thus effectively inhibiting down-stream activation of IFN signaling. In the present study, we demonstrated that HEV inhibits polyinosinic-polycytidylic acid (poly(I:C))-induced $IFN-{\beta}$ transcriptional induction. Moreover, by using reporter assay with individual HEV-encoded gene, we showed that HEV methyltransferase (MeT), a non-structural protein, significantly decreases RIG-I-induced $IFN-{\beta}$ induction and $NF-{\kappa}B$ signaling activities in a dose-dependent manner. Taken together, we report here that MeT, along with PCP, is responsible for the inhibition of RIG-I-induced activation of type I IFNs, expanding the list of HEV-encoded antagonists of the host innate immunity.

• The Korean Journal of Physiology and Pharmacology
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• 제21권3호
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• pp.279-286
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• 2017

The root bark extract of Aralia taibaiensis is used traditionally for the treatment of diabetes mellitus in China. The total saponin extracted from Aralia Taibaiensis (sAT) has effective combined antihyperglycemic and hypolipidemic activities in experimental type 2 diabetic rats. However, the active compounds have not yet been fully investigated. In the present study, we examined effects of twelve triterpenoid saponins on AMP-activated protein kinase (AMPK) activation, and found that compound 28-O-${\beta}$-D-glucopyranosyl ester (AT12) significantly increased phosphorylation of AMPK and Acetyl-CoA carboxylase (ACC). AT12 effectively decreased blood glucose, triglyceride (TG), free fatty acid (FFA) and low density lipoprotein-cholesterol (LDL-C) levels in the rat model of type 2 diabetes mellitus (T2DM). The mechanism by which AT12 activated AMPK was subsequently investigated. Intracellular ATP level and oxygen consumption were significantly reduced by AT12 treatment. The findings suggested AT12 was a novel AMPK activator, and could be useful for the treatment of metabolic diseases.

• Archives of Pharmacal Research
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• 제21권2호
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• pp.120-127
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• 1998

Peroxisome proliferators induce hepatic peroxisome proliferation and hepatic tumors in rodents. These chemicals increase the expression of the peroxisomal $\beta$-oxidation pathway and the cytochrome P-450 4A family, which metabolizes lipids, including eicosanoids. Peroxisome proliferators transiently induce increased cell proliferation in vivo. However, peroxisome proliferators are weakly mitogenic and are not co-mitogenic with epidermal growth factor (EGF) in cultured hepatocytes. Earlier study found that the peroxisome proliferator ciprofibrate is cornitogenic with eicosanoids. In order to study possible mechanisms of the comitogenicity of peroxisome proliferator ciprofibrate and eicosanoids' we hypothesized that the co-mitogenicity may result from synergistic or additive increases of second messengers in mitogenic signal pathways. We therefore examined the effect of the peroxisome proliferator ciprofibrate, prostaglandin $F_2_{\alpha}$($PGF_2{\alpha}$) and the combination of ciprofibrate and $PGF_2{\alpha}$ with or without growth factors on the protein kinase C (PKC) activity, and inositol-1, 4, 5-triphosphate ($IP_{3-}$) and intracellular calcium ($[Ca^{2+}]_i$) concentrations in cultured rat hepatocytes. The combination of ciprofibrate and $PGF_2{\alpha}$ significantly increased particulate PKC activity. The combination of ciprofibrate and $PGF_2{\alpha}$ also significantly increased EGF, transforming growth factor-$\alpha$ ($TGF_2{\alpha}$) and hepatic growth factor (HGF)-induced particulate PKC activity. The combination of ciprofibrate and $PGF_2_\alpha$greatly increased $[Ca^{2+}]_i$. However, the increases of PKC activity and $[Ca^{2+}]_i$ by ciprofibrate and $PGF_2{\alpha}$ alone were much smaller. Neither ciprofibrate or $PGF_2{\alpha}$ alone nor the combination of ciprofibrate and $PGF_2{\alpha}$ significantly increased the formation of $IP_3$. The combination of ciprofibrate and $PGF_2{\alpha}$, however, blocked the inhibitory effect of $TGF-{\beta}$ on particulate PKC activity and formation of $IP_3$ induced by EGF. These results show that co-mitogenicity of the peroxisome proliferator ciprofibrate and eicosanoids may result from the increase in particulate PKC activity and intracellular calcium concentration but not from the formation of $IP_3$.

• 대한본초학회지
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• 제26권3호
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• pp.23-29
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• 2011

Objective : The purpose of this study was to investigate the anti-inflammatory effects of aqueous extract from Scolopendrae Corpus (SC) on lipopolysaccharide (LPS)-induced inflammatory response. Methods : To evaluate the anti-inflammatory effects of SC, we examined the inflammatory mediators such as nitric oxide (NO) and pro-inflammatory cytokines (TNF-a, inteleukin (IL)-$1{\beta}$ and IL-6) on RAW 264.7 cells. We also examined molecular mechanisms such as mitogen-activated protein kinases (MAPKs) and inhibitory kappa B a ($I{\kappa}$-Ba) using western blot. Furthermore, we also investigated the effect of SC on LPS-induced endotoxin shock. Results : Extract from SC itself had not any cytotoxic effect in RAW 264.7 cells. Aqueous extract from SC inhibited LPS-induced NO production and iNOS expression. SC pre-treatment also inhibited IL-$1{\beta}$, IL-6 production in RAW 264.7 cells. To investigate inhibitory effects of SC on inflammatory mediators, activation of MAPKs was examined. SC inhibited the phosphorylation of p38 kinases (p38), c-Jun $NH_2$-terminal kinase (JNK) and also the degradation of $I{\kappa}$-$B{\alpha}$ in RAW 264.7 cells stimulated with LPS. Furthermore, SC administration reduced LPS-induced endotoxin shock. Conclusion : SC down-regulated LPS-induced production of inflammatory mediators through inhibition of activation of p38, JNK and degradation of $I{\kappa}$-$B{\alpha}$. Taken together, our results suggest that SC may be a beneficial drug against inflammatory diseases such as sepsis.

• 생명과학회지
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• 제27권2호
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• pp.155-163
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• 2017

상엽은 뽕나무 잎을 건조한 약재로서 항염증, 항당뇨, 미백, 항산화, 항박테리아, 항알러지 및 면역조절 등과 같은 여러 가지 약리작용을 하는 것으로 알려져 있으나 항비만 효능에 대한 연구는 부족한 실정이다. 본 연구에서는 상엽 에탄올 추출물(ethanol extracts of Mori Folium, EEMF)이 유발하는 항비만 효능을 확인하기 위하여 3T3-L1 지방전구세포가 지방세포로 분화되는 과정에서 EEMF가 어떠한 영향을 미치는 지를 조사하였다. 3T3-L1 지방전구세포의 분화유도 시 EEMF를 처리하였을 경우 지방세포의 특징인 지방방울의 수 및 지방함량이 농도의 존적으로 감소하였으며, triglyceride의 생성도 억제되는 것으로 나타났다. 또한 EEMF는 pro-adipogenic transcription factors인 SREBP-1c, $PPAR{\gamma}$, $C/EBP{\alpha}$ 및 $C/EBP{\beta}$ 의 발현억제와 함께 adipocyte-specific genes인 aP2 및 Leptin의 발현억제도 유발하는 것으로 조사되었다. 특히 EEMF는 AMPK 및 ACC의 인산화를 억제하는 것으로 나타났지만 AMPK 억제제인 compound C를 이용하여 AMPK의 활성을 억제하였을 경우 EEMF에 의하여 유발되는 pro-adipogenic transcription factors 및 adipocyte-specific genes의 억제현상이 회복되었다. 이상의 결과에서 EEMF가 유발하는 adipogenesis의 억제는 AMPK signaling pathway의 활성화를 통하여 유발된다는 것을 알 수 있었으며, 추가적인 연구를 통하여 상엽에 함유되어 있는 유효성분에 대한 분석이 필요할 것으로 생각된다.

• 대한소아치과학회지
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• 제25권3호
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• pp.635-648
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• 1998

The clinical use of fluoride with a well known osteogenic action in osteoporotic patients is rational, because this condition is characterized by impaired bone formation. However, its anabolic effect has not been demonstrated well in vitro. The purpose of this study was to investigate the effects of sodium fluoride on the physiological role of osteoblastic cell. Osteoblastic cells were isolated from fetal rat calvaria. The results were as follows : 1. Mineralized nodules were shown in osteoblastic cell cultures, which had been maintained in the presence of ascorbic acid and ${\beta}-glycerophosphate$ up to 21 days. When cultures were treated with pulses of 48 hr duration before apparent mineralization was occurring, 2-fold increased in their number was detected. 2. Alkaline phosphatase activity of osteoblastic cells was inhibited by sodium fluoride in dose dependent manner. 3. The effect of sodium fluoride on the osteoblastic cell proliferation was measured by the incorporation of $[^3H]$-thymidine into DNA. As a result, sodium fluoride at $1{\sim}100{\mu}M$ increased the $[^3H]$-thymidine incorporation into DNA in a dose dependent manner. 4. The signaling mechanism activated by sodium fluoride dose-dependently enhanced the tyrosine phosphorylation of the adaptor molecule $Shc^{p66}$ and their association with Grb2, one of earlier events in a MAP kinase activation pathway cascade used by a significant subset of G protein-coupled receptors. 5. The phosphorylation of CREB(cAMP response element binding protein)was inhibited by the sodium fluoride in MC3T3E1 cells. In conclusion, the results of this study suggested that the mitogenic effect of the sodium fluoride in MC3T3E1 cell was stimulated in a dose-dependent manner and suggested "an important role for the interaction between She and Grb2" in controlling the proliferation of osteoblasts.

• Biomolecules & Therapeutics
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• 제31권3호
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• pp.285-297
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• 2023

Alzheimer's disease (AD) is a neurodegenerative disease with progressive memory loss and the cognitive decline. AD is mainly caused by abnormal accumulation of misfolded amyloid β (Aβ), which leads to neurodegeneration via a number of possible mechanisms such as down-regulation of brain-derived neurotrophic factor-tropomyosin-related kinase B (BDNF-TRKB) signaling pathway. 7,8-Dihydroxyflavone (7,8-DHF), a TRKB agonist, has demonstrated potential to enhance BDNF-TRKB pathway in various neurodegenerative diseases. To expand the capacity of flavones as TRKB agonists, two natural flavones quercetin and apigenin, were evaluated. With tryptophan fluorescence quenching assay, we illustrated the direct interaction between quercetin/apigenin and TRKB extracellular domain. Employing Aβ folding reporter SH-SY5Y cells, we showed that quercetin and apigenin reduced Aβ-aggregation, oxidative stress, caspase-1 and acetylcholinesterase activities, as well as improved the neurite outgrowth. Treatments with quercetin and apigenin increased TRKB Tyr516 and Tyr817 and downstream cAMP-response-element binding protein (CREB) Ser133 to activate transcription of BDNF and BCL2 apoptosis regulator (BCL2), as well as reduced the expression of pro-apoptotic BCL2 associated X protein (BAX). Knockdown of TRKB counteracted the improvement of neurite outgrowth by quercetin and apigenin. Our results demonstrate that quercetin and apigenin are to work likely as a direct agonist on TRKB for their neuroprotective action, strengthening the therapeutic potential of quercetin and apigenin in treating AD.

• International Journal of Oral Biology
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• 제34권2호
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• pp.73-79
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• 2009

Cytosolic $Ca^{2+}$ is an important regulator of tumor cell proliferation and metastasis. Recently, the strategy of blocking receptors and channels specific to certain cancer cell types has emerged as a potentially viable future treatment. Oral squamous cell carcinoma is an aggressive form of cancer with a high metastasis rate but the receptor-mechanisms involved in $Ca^{2+}$ signaling in these tumors have not yet been elucidated. In our present study, we report that bradykinin induces $Ca^{2+}$ signaling and its modulation in the human oral squamous carcinoma cell line, HSC-3. Bradykinin was found to increase the cytosolic $Ca^{2+}$ levels in a concentration-dependent manner. This increase was inhibited by pretreatment with the phospholipase C-${\beta}$ inhibitor, U73122, and also by 2-aminoethoxydiphenyl borate, an inhibitor of the inositol 1,4,5-trisphosphate receptor. Pretreatment with extracellular ATP also inhibited the peak bradykinin-induced $Ca^{2+}$ rise. In contrast, the ATP-induced rise in cytosolic $Ca^{2+}$ was not affected by pretreatment with bradykinin. Pretreatment of the cells with either forskolin or phorbol 12-myristate 13-acetate (activators of adenylyl cyclase and protein kinase C, respectively) prior to bradykinin application accelerated the recovery of cytosolic $Ca^{2+}$ to baseline levels. These data suggest that bradykinin receptors are functional in $Ca^{2+}$ signaling in HSC-3 cells and may therefore represent a future target in treatment strategies for human oral squamous cell carcinoma.