• Toxicological Research
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• 제22권3호
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• pp.283-291
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• 2006

The survival and growth of epithelial cells depends on adhesion to the extracellular matrix. An adhesion signal may regulate the initiation of differentiation, since epidermal keratinocytes differentiate as they leave the basement membrane. A metabolically dead cornified cell envelope is the end point of epidermal differentiation so that this process may be viewed as a specialized form of programmed cell death. In order to investigate the precise cellular signaling events loading to terminal differentiation of keratinocytes, we have utilized HaCaT cells to monitor the biological consequences of $Ca^{2+}$ stimulation and numerous downstream signaling pathways, including activation of the extracellular signal-regulated protein kinase(ERK) pathway and activation of phosphatidylinositol 3-kinase(PI3K). The results presented in this study show that $Ca^{2+}$ function as potent agents for the differentiation of HaCaT keratinocytes, and this differentiation depends or the activation of ERK, Protein kinase B(PKB) and p70 ribosomal protein S6 kinase(p70S6K). Finally, the results show that the expression of Activator protein 1(AP-1; c-Jun and c-Fos) increased following $Ca^{2+}$-mediated differentiation of HaCaT cells, suggesting that ERK-mediated AP-1 expression is critical for initiating the terminal differentiation of keratinocytes.

• 생명과학회지
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• 제28권1호
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• pp.43-49
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• 2018

Chrysoeriol은 alfalfa에서 주로 발견되는, 식물계에 많이 분포하고 있는 flavone으로 전통의학에서 소화불량, 천식, 비뇨기계 이상의 치료에 사용되어 왔다. 최근의 연구에서는 항염증 효과가 있는 것으로 밝혀졌으나 항산화 효과에 대한 분석은 없었다. 본 연구에서는 chrysoeriol의 항산화 효과와 그 분자적 기전을 RAW 264.7 cell에서 세포생존율, reactive oxygen species (ROS)와 Western blot분석을 통해 알아보고자 하였다. Chrysoeriol은 lipopolysaccharide(LPS)에 의해 발생한 ROS를 세포독성없이 농도의존적으로 제거하였다. 그리고 항산화효과를 보이는 2상 효소 중 하나인 heme oxygenase (HO)-1의 발현을 강하게 유도하였고, 그와 동시에 전사인자인 Nrf2의 핵내 이동도 촉진하는 것으로 밝혀졌다. 특히, 산화스트레스에 대한 세포내 산화환원항상성 유지에 중요한 역할을 하고 있는 것으로 알려진 mitogen activated protein kinase (MAPK)와 phosphoinositide 3-kinase (PI3K)의 분석결과, chrysoeriol은 extracellular signal regulated kinase (ERK), c-Jun NH2-terminal kinase (JNK)와 p38의 인산화를 통해 HO-1의 발현을 유도하는 것으로 나타났다. HO-1에 의한 항산화 효과를 확인하기 위하여 chrysoeriol을 전처리한 후 t-BHP에 의한 산화 스트레스에 세포를 노출시킨 결과, chrysoeriol 처리에 의해 세포사멸이 줄어드는 것을 확인하였고, HO-1의 유도제와 억제제의 처리에 따라 세포생존율 또한 조절되는 것을 확인할 수 있었다. 따라서, chrysoeriol은 HO-1의 발현을 유도하여 항산화 효과를 높이고 이것은 Nrf2/MAPK 신호전달 체계에 의한다는 것을 알 수 있었다.

• The Korean Journal of Physiology and Pharmacology
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• 제17권3호
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• pp.223-228
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• 2013

The calcium-activated $K^+$ ($BK_{Ca}$) channel is one of the potassium-selective ion channels that are present in the nervous and vascular systems. $Ca^{2+}$ is the main regulator of $BK_{Ca}$ channel activation. The $BK_{Ca}$ channel contains two high affinity $Ca^{2+}$ binding sites, namely, regulators of $K^+$ conductance, RCK1 and the $Ca^{2+}$ bowl. Lysophosphatidic acid (LPA, 1-radyl-2-hydroxy-sn-glycero-3-phosphate) is one of the neurolipids. LPA affects diverse cellular functions on many cell types through G protein-coupled LPA receptor subtypes. The activation of LPA receptors induces transient elevation of intracellular $Ca^{2+}$ levels through diverse G proteins such as $G{\alpha}_{q/11}$, $G{\alpha}_i$, $G{\alpha}_{12/13}$, and $G{\alpha}s$ and the related signal transduction pathway. In the present study, we examined LPA effects on $BK_{Ca}$ channel activity expressed in Xenopus oocytes, which are known to endogenously express the LPA receptor. Treatment with LPA induced a large outward current in a reversible and concentration-dependent manner. However, repeated treatment with LPA induced a rapid desensitization, and the LPA receptor antagonist Ki16425 blocked LPA action. LPA-mediated $BK_{Ca}$ channel activation was also attenuated by the PLC inhibitor U-73122, $IP_3$ inhibitor 2-APB, $Ca^{2+}$ chelator BAPTA, or PKC inhibitor calphostin. In addition, mutations in RCK1 and RCK2 also attenuated LPA-mediated $BK_{Ca}$ channel activation. The present study indicates that LPA-mediated activation of the $BK_{Ca}$ channel is achieved through the PLC, $IP_3$, $Ca^{2+}$, and PKC pathway and that LPA-mediated activation of the $BK_{Ca}$ channel could be one of the biological effects of LPA in the nervous and vascular systems.

• Archives of Pharmacal Research
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• 제29권10호
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• pp.911-920
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• 2006

Phenolic antioxidant butylated hydroxyanisole (BHA) is a commonly used food preservative with broad biological activities, including protection against chemical-induced carcinogenesis, acute toxicity of chemicals, modulation of macromolecule synthesis and immune response, induction of phase II detoxifying enzymes, as well as its undesirable potential tumor-promoting activities. Understanding the molecular basis underlying these diverse biological actions of BHA is thus of great importance. Here we studied the pharmacokinetics, activation of signaling kinases and induction of phase II/III drug metabolizing enzymes/transporter gene expression by BHA in the mice. The peak plasma concentration of BHA achieved in our current study after oral administration of 200 mg/kg BHA was around $10\;{\mu}M$. This in vivo concentration might offer some insights for the many in vitro cell culture studies on signal transduction and induction of phase II genes using similar concentrations. The oral bioavailability (F) of BHA was about 43% in the mice. In the mouse liver, BHA induced the expression of phase II genes including NQO-1, HO-1, ${\gamma}-GCS$, GST-pi and UGT 1A6, as well as some of the phase III transporter genes, such as MRP1 and Slco1b2. In addition, BHA activated distinct mitogen-activated protein kinases (MAPKs), c-Jun N-terminal kinase (JNK), extracellular signal-regulated protein kinase (ERK), as well as p38, suggesting that the MAPK pathways may play an important role in early signaling events leading to the regulation of gene expression including phase II drug metabolizing and some phase III drug transporter genes. This is the first study to demonstrate the in vivo pharmacokinetics of BHA, the in vivo activation of MAPK signaling proteins, as well as the in vivo induction of Phase II/III drug metabolizing enzymes/transporters in the mouse livers.

• BMB Reports
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• 제33권6호
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• pp.454-462
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• 2000

Interleukin-4(IL-4) is known to be a major cytokine regulating immunoglobulin E(IgE) response by the induction of IgE production and type II IgE receptor(IgER II: CD23) expression. Recently, however, the role of neuroendocrine factors has been implicated in modulating the IgE response. Among various neuroendocrine growth factors, we investigated the effects of the insulin-like growth factor-1(IGF-1) since IL-4 and IGF-1 share common intracellular signaling molecules, such as the insulin receptor substrate-1/2(IRS-1/2) to induce a specific cellular response. In the human peripheral blood mononuclear cell (PBMC) cultures, IGF-1 was capable of inducing a substantial level of IgE production in a dose-dependent manner. It also noticeably upregulated the IL-4-induced or IL-4 plus anti-CD40-induced IgE production. Similarly, the IGF-1-induced IgE production was enhanced by IL-4 or anti-CD40 in an additive manner, which became saturated at high concentrations of IGF-1. Although IGF-1 alone did not induce IgER II (CD23) expression, it augmented the IL-4-induced surface CD23 expression in a manner similar to the action of anti-CD40. These results imply that IGF-1 is likely to utilize common signaling pathways with IL-4 and anti-CD40 to induce IgE and IgER II expression. In support of this notion, we observed that IGF-1 enhanced the IL-4-induced signal transducers and activators of transcription 6(STAT6) activation and independently induced $NF-{\kappa}B$ activation. Both of these bind to the IgE(C) or IgER II (CD23) promoters. Together, our data suggest that IL-4 and IGF-1 work cooperatively to activate STAT6 and $NF-{\kappa}B$. This leads to the subsequent binding of these transcription factors to the $C{\varepsilon}$ and CD23 promoters to enhance the expression of IgE and IgER II. The observed differential ability of IGF-1 on the induction of IgE vs. IgER II is discussed based on the different structure of the two promoters.

• 대한화장품학회지
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• 제30권2호
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• pp.247-251
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• 2004

자외선은 피부에 염증반응이나 광노화와 같은 다양한 반응을 야기시킨다고 알려져 있다. 특히 자외선에 의해 손상을 받은 피부는 콜라겐의 양이 감소되어 있는데, 이는 자외선에 의해 피부 내에서 콜라겐을 분해하는 효소(MMP, matrix metalloproteinases)의 양이 증가하기 때문이라고 알려져 왔다. 또한 자외선에 의해 피부에서 염증반응이 유발되는데, 이러한 반응은 프로스타글란딘이라는 물질에 의해 매개되며, 이 프로스타글란딘에 의해서도 MMP가 증가한다고 알려져 왔다. 본 연구에서는 6개월의 임상실험을 통해 광노화된 피부에서 주름형성억제효능이 뛰어난 FDP(fructose 1.6-diphosphate)의 작용기전을 인체각질형성 세포를 이용하여 연구하였다. 인체각질형성세포에 자외선을 조사할 경우 프로스타글란딘, COX-2(cyclooxygenase-2), MMPs의 활성이 증가하는 것을 확인하였며, 이는 FDP의 처리에 의해 감소되었다. 이러한 효과는 자외선에 의해 인체각질형성세포에서 발생하는 신호전달과정을 억제함으로써 일어나는 효과임이 증명되었다. 따라서, FDP는 자외선에 의해 일어나는 세포 내 신호전달과정을 억제하며, 이로 인해 야기되는 프로스타글란딘, COX-2, MMPs의 증가를 억제함으로써 피부의 광노화를 억제할 수 있는 원료로 여겨진다.

• BMB Reports
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• 제55권4호
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• pp.198-203
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• 2022

As negative regulators of cytokine signaling pathways, suppressors of cytokine signaling (SOCS) proteins have been reported to possess both pro-tumor and anti-tumor functions. Our recent studies have demonstrated suppressive effects of SOCS1 on epithelial to mesenchymal signaling in colorectal cancer cells in response to fractionated ionizing radiation or oxidative stress. The objective of the present study was to determine the radiosensitizing action of SOCS1 as an anti-tumor mechanism in colorectal cancer cell model. In HCT116 cells exposed to ionizing radiation, SOCS1 over-expression shifted cell cycle arrest from G2/M to G1 and promoted radiation-induced apoptosis in a p53-dependent manner with down-regulation of cyclin B and up-regulation of p21. On the other hand, SOCS1 knock-down resulted in a reduced apoptosis with a decrease in G1 arrest. The regulatory action of SOCS1 on the radiation response was mediated by inhibition of radiation-induced Jak3/STAT3 and Erk activities, thereby blocking G1 to S transition. Radiation-induced early ROS signal was responsible for the activation of Jak3/Erk/STAT3 that led to cell survival response. Our data collectively indicate that SOCS1 can promote radiosensitivity of colorectal cancer cells by counteracting ROS-mediated survival signal, thereby blocking cell cycle progression from G1 to S. The resulting increase in G1 arrest with p53 activation then contributes to the promotion of apoptotic response upon radiation. Thus, induction of SOCS1 expression may increase therapeutic efficacy of radiation in tumors with low SOCS1 levels.

• 한국음향학회지
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• 제41권1호
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• pp.108-113
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• 2022

소음상황에서의 어음 이해 능력은 효과적인 의사소통을 위한 중요한 기술이다. 이러한 능력을 평가하는 방법으로 Hearing In Noise Test(HINT) 도구가 제안되어 사용되고 있다. 하지만 국내에서 이 유용한 도구가 초기의 기대와 달리 임상에서 적극적으로 활용되지 못하고 있다. 연령이 높아질수록 정상 청력을 가지고 있을지라도 양이에서 들어오는 신호들을 처리하는데 어려움을 겪게 되고, 특히 배경 소음이 있는 상황에서 듣기는 더욱 어려워진다. 하지만, 어음이해에 상당한 문제점을 갖고 있는 노인 인구들을 임상적으로 평가하는 도구들이 많지 않다. 본 연구에서는 이러한 검사법이 근거하고 있는 기전에 있는 인지적 특성과 임상에서의 문제점을 분 석하여 개선점을 제안하고자 한다. 기본 임상 사례로 정상 청력을 가진 20대와 70대의 대표적 HINT점수를 비교하고, 소음이 어떤 조건에서 제시되는가에 따른 문장 인지 특징을 조명하였다. 대상자의 HINT score는 Quiet(Q), Noise Front(NF), Noise Right(NR), Noise Left(NF)조건에서 분석되었다. 여러 임상적 관점에서 유용한 점은 배경 소음이 있을 때 노인의 경우 청년보다 더 많은 신호대잡음비를 필요함을 나타내는 정량적 변수를 보여주고, 양이차폐감소차이(Binaural Masking Level Difference, BMLD)효과도 보여주고 있다는 점이다. 효과적 임상적 적용에는 세부 연령대별 비교 가능한 표준 자료가 극히 부족한 실정이다. 이러한 유용성 확인과 함께 임상 관련 개선점을 제시하였다.

• Journal of Animal Science and Technology
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• 제64권5호
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• pp.922-936
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• 2022

5-Hydroxytryptamine (5-HT), a monoamine, as a local regulator in the mammary gland is a chemical signal produced by the mammary epithelium cell. In cows, studies have shown that 5-HT is associated with epithelial cell apoptosis during the degenerative phase of the mammary gland. However, studies in other tissues have shown that 5-HT can effectively promote cell viability. Whether 5-HT could have an effect on mammary cell viability in dairy cows is still unknown. The purpose of this study was to determine: (1) effect of 5-HT on the viability of bovine mammary epithelial cells and its related signaling pathways, (2) interaction between prolactin (PRL) and 5-HT on the cell viability. The bovine mammary alveolar cell-T (MAC-T) were cultured with different concentrations of 5-HT for 12, 24, 48 or 72 hours, and then were assayed using cell counting kit-8, polymerase chain reaction (PCR) and immunobloting. The results suggested that 20 μM 5-HT treatment for 12 or 24 h promote cell viability, which was mainly induced by the activation of 5-HT receptor (5-HTR) 1B and 4, because the increase caused by 5-HT vanished when 5-HTR 1B and 4 was blocked by SB224289 and SB204070. And protein expression of mammalian target of rapamycin (mTOR), eukaryotic translation elongation factor 2 (eEF2), janus kinase 2 (JAK2) and signal transducer and activator of transcription 5 (STAT5) were decreased after blocking 5-HT 1B and 4 receptors. When MAC-T cells were treated with 5-HT and PRL simultaneously for 24 h, both the cell viability and the level of mTOR protein were significantly higher than that cultured with 5-HT or PRL alone. In conclusion, our study suggested that 5-HT promotes the viability of MAC-T cells by 5-HTR 1B and/or 4. Furthermore, there is a reciprocal relationship between PRL and 5-HT.

• 대한임상검사과학회지
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• 제55권4호
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• pp.306-313
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• 2023

패혈증은 병원성 감염에 의해 여러 장기에 나타나는 전신성 염증 반응으로, 현재로서는 유망한 치료제가 없다. Signal transducer and activator of transcription 3 (STAT3)은 세포 신호전달 전사 인자로서 항염증 및 염증 반응과 관련된 다양한 세포의 생물학적 과정에서 중요한 역할을 한다. Niclosamide는 FDA에서 승인된 구충제로 STAT3 조절에 관여한다고 알려져 있다. C57BL/6 마우스에 복강 주사로 지질 다당체 (lipopolysaccharide, LPS)를 투여해 패혈증을 유발하였고, Niclosamide를 LPS 주사 2시간 후에 경구 투여하였다. 본 연구에서 Niclosamide가 LPS로 유발된 패혈증 모델의 생존률과 폐 손상을 완화시켰고, 혈청 내 interleukin (IL)-6, 종양괴사인자(tumor necrosis factor-α, TNF-α), IL-1β, AST, ALT, LDH 수치를 유의하게 감소시켰다. 또한 폐 조직 면역 블롯을 통해 PI3K, AKT, NF-κB, STAT3 신호 전달 경로가 Niclosamide에 의해 조절되는 것을 확인하였다. Niclosamide는 LPS를 자극한 RAW 264.7 세포주에서 IL-6, TNF-α, IL-1β와 같은 염증성 사이토카인의 발현을 감소시켰으며, 또한 STAT3의 인산화를 감소시켰다. 본 연구를 통해 Niclosamide에 의한 STAT3 조절이 염증 반응을 억제함으로써 패혈증 모델에 대한 새로운 치료 전략을 제시하였다.