• The Korean Journal of Physiology and Pharmacology
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• 제19권3호
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• pp.219-228
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• 2015

Excessive microglial activation and subsequent neuroinflammation lead to synaptic loss and dysfunction as well as neuronal cell death, which are involved in the pathogenesis and progression of several neurodegenerative diseases. Thus, the regulation of microglial activation has been evaluated as effective therapeutic strategies. Although dieckol (DEK), one of the phlorotannins isolated from marine brown alga Ecklonia cava, has been previously reported to inhibit microglial activation, the molecular mechanism is still unclear. Therefore, we investigated here molecular mechanism of DEK via extracellular signal-regulated kinase (ERK), Akt and nicotinamide adenine dinuclelotide phosphate (NADPH) oxidase-mediated pathways. In addition, the neuroprotective mechanism of DEK was investigated in microglia-mediated neurotoxicity models such as neuron-microglia co-culture and microglial conditioned media system. Our results demonstrated that treatment of anti-oxidant DEK potently suppressed phosphorylation of ERK in lipopolysaccharide (LPS, $1{\mu}g/ml$)-stimulated BV-2 microglia. In addition, DEK markedly attenuated Akt phosphorylation and increased expression of $gp91^{phox}$, which is the catalytic component of NADPH oxidase complex responsible for microglial reactive oxygen species (ROS) generation. Finally, DEK significantly attenuated neuronal cell death that is induced by treatment of microglial conditioned media containing neurotoxic secretary molecules. These neuroprotective effects of DEK were also confirmed in a neuron-microglia co-culture system using enhanced green fluorescent protein (EGFP)-transfected B35 neuroblastoma cell line. Taken together, these results suggest that DEK suppresses excessive microglial activation and microglia-mediated neuronal cell death via downregulation of ERK, Akt and NADPH oxidase-mediated pathways.

• The Korean Journal of Physiology and Pharmacology
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• 제17권3호
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• pp.203-208
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• 2013

As the abnormal proliferation of vascular smooth muscle cells (VSMCs) plays a critical role in the development of atherosclerosis and vascular restenosis, a candidate drug with antiproliferative properties is needed. We investigated the antiproliferative action and underlying mechanism of a newly synthesized naphthoquinone derivative, 5,8-dimethoxy-2-nonylamino-naphthalene-1,4-dione (2-nonylamino-DMNQ), using VSMCs treated with platelet-derived growth factor (PDGF). 2-Nonylamino-DMNQ inhibited proliferation and cell number of VSMCs induced by PDGF, but not epidermal growth factor (EGF), in a concentration-dependent manner without any cytotoxicity. This derivative suppressed PDGF-induced $[^3H]$-thymidine incorporation, cell cycle progression from $G_0/G_1$ to S phase, and the phosphorylation of phosphor-retinoblastoma protein (pRb) as well as the expression of cyclin E/D, cyclin-dependent kinase (CDK) 2/4, and proliferating cell nuclear antigen (PCNA). Importantly, 2-nonylamino-DMNQ inhibited the phosphorylation of PDGF receptor${\beta}$(PDGF-$R{\beta}$) enhanced by PDGF at $Tyr^{579}$, $Tyr^{716}$, $Tyr^{751}$, and $Tyr^{1021}$ residues. Subsequently, 2-nonylamino-DMNQ inhibited PDGF-induced phosphorylation of STAT3, ERK1/2, Akt, and $PLC{\gamma}1$. Therefore, our results indicate that 2-nonylamino-DMNQ inhibits PDGF-induced VSMC proliferation by blocking PDGF-$R{\beta}$ autophosphorylation, and subsequently PDGF-$R{\beta}$-mediated downstream signaling pathways.

• 대한화장품학회지
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• 제37권3호
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• pp.211-218
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• 2011

Glycogen synthase kinase 3 beta (GSK3${\beta}$)의 선택적 저해제인 Kenpaullone가 B16 멜라노마 및 사람의 멜라노사이트에 미치는 멜라닌 합성능을 조사하였다. Kepaullone은 B16 멜라노마 및 사람의 멜라노사이트에 대하여 세포증식에는 영향이 없는 범위 내에서 농도 의존적으로 멜라닌 합성을 촉진시켰다. B16 멜라노마 세포에 Kenpaullone을 첨가 48 h 후 tyrosinase 활성이 증가하였으며, 농도별 처리에 대하여 tyrosinase 단백질의 발현 및 tyrosinase mRNA양이 증가함을 관찰하였다. 결론적으로 Kenpaullone는 B16 멜라노마 세포에서 tyrosinase 효소의 발현을 증가시켜 멜라닌 합성을 촉진하는 것으로 판단되어진다. 따라서 GSK3${\beta}$ 저해제가 멜라닌 합성을 촉진시키는 결과는 백반증과 같은 저색소관련 질병의 치료제 개발의 가능성을 갖고 있는 소재로서 응용가능하리라고 판단되어진다.

• 대한화장품학회지
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• 제33권2호
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• pp.87-92
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• 2007

본 연구에서는 천연 미백소재 개발을 위하여 제주도 연안에 서식하는 해조류 중 홍조류의 일종인 새발 추출물의 멜라닌 생성에 연관된 생리활성을 분석하였다. 그 결과, 새발 추출물의 폴리페놀 함량은 2.0 % 이하였고, 라디칼 소거활성(DPPH)은 $IC_{50}$값이 $2,000{\mu}g/mL$ 이상이었으며, 세포독성은 관찰되지 않았다. 그리고 생쥐의 B16/F10 흑색종 세포에서 멜라닌 생합성에 관련된 효소의 저해효과를 알아본 결과, 알파-멜라노사이트 자극 호르몬에 의해 유도된 extracellular signal-regulated kinase 1/2 (ERK 1/2)의 활성화를 억제함으로써 티로시나제와 티로시나제 연관 단백질 1을 저해하는 것으로 확인되었다. 따라서 새발 추출물은 멜라닌 생합성에 필수적인 효소인 티로시나제의 저해활성과 티로시나제 연관 단백질 1의 발현억제 효과가 뛰어난 것으로 분석되었다. 그러므로 홍조류인 새발(Acanthopeltis japonica)의 추출물은 멜라닌 생성 자극제로 유도된 신호전달경로를 저해하는 미백 기능성 화장품 소재로서의 활용 가능성이 높을 것으로 사료된다.

• 생명과학회지
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• 제21권1호
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• pp.141-145
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• 2011

본 연구에서는 전사억제제(transcriptional inhibitor)로 알려진 actinomycin D가 전사조절인자(transcription factor)인 STAT의 인산화를 유도한다는 것을 확인하였다. Actinomycin D 처리 시 STAT1의 Tyr701, Ser727 인산화는 유도되지 않았지만 STAT3의 Tyr705 잔기의 인산화를 특이적으로 유도하는 것을 확인하였다. Actinomycin D에 의한 STAT3의 Tyr705 인산화 유도가 어떠한 기전을 통한 것인지 확인하기 위해서 관련 인자의 단백질 및 mRNA 발현을 확인한 결과 SOCS3의 단백질 및 mRNA 발현의 감소를 확인하였다. STAT3의 탈인산화를 유도한다고 알려진 tyrosine phosphatase인 SHP-1와 STAT의 upstream kinase인 JAK2의 인산화는 변화가 없었다. 또한 actinomycin D 뿐 아니라 다른 전사억제제인 DRB를 처리 하였을 경우에도 STAT3의 Tyr705 인산화가 유도되는 것을 확인하였다. 이상의 결과는 전사억제제에 의하여 특이적인 SOCS3 단백질 발현감소는 SOCS3의 하류의 target인 STAT3 인산화를 유도하였다.

• 생명과학회지
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• 제20권7호
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• pp.1093-1099
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• 2010

항암 효과와 항산화 기능을 가지는 것으로 알려진 lycopene은 심혈관에서의 기능이 현재까지 잘 알려져 있지 않다. 본 연구에서는 lycopene의 심혈관 기능을 알기 위해 혈관내피세포를 이용해 다양한 세포실험을 수행하였다. 그 결과, lycopene은 내피세포의 성장 및 이동을 촉진하였으나 세포사멸에는 영향이 없었다. 또한, 백혈구의 혈관내피세포 부착을 억제하였고 내피세포 내 신호전달물질인 MAPK들의 활성을 촉발하였다. MAPK의 활성 억제제를 이용한 신호전달기전 연구실험 결과, ERK와 p38 MAPK의 활성은 세포성장에 관여하고, JNK의 활성은 세포이동에 관여함을 확인하였다. 종합하면, lycopene은 혈관내피세포의 신호전달 물질인 MAPK들를 통해 세포성장 및 이동을 촉진시키며, LPS에 의한 THP-1의 내피세포 부착을 억제 하는 등 혈관내피세포의 다양한 생리활성을 조절한다. Lycopene의 이러한 혈관내피세포 기능들은 lycopene이 혈관질환 치료제로 응용될 가능성이 있음을 의미한다.

• Molecules and Cells
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• 제38권2호
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• pp.138-144
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• 2015

Raloxifene is a selective estrogen receptor modulator (SERM) that binds to the estrogen receptor (ER), and exhibits potent anti-tumor and autophagy-inducing effects in breast cancer cells. However, the mechanism of raloxifene-induced cell death and autophagy is not well-established. So, we analyzed mechanism underlying death and autophagy induced by raloxifene in MCF-7 breast cancer cells. Treatment with raloxifene significantly induced death in MCF-7 cells. Raloxifene accumulated GFP-LC3 puncta and increased the level of autophagic marker proteins, such as LC3-II, BECN1, and ATG12-ATG5 conjugates, indicating activated autophagy. Raloxifene also increased autophagic flux indicators, the cleavage of GFP from GFP-LC3 and only red fluorescence-positive puncta in mRFP-GFP-LC3-expressing cells. An autophagy inhibitor, 3-methyladenine (3-MA), suppressed the level of LC3-II and blocked the formation of GFP-LC3 puncta. Moreover, siRNA targeting BECN1 markedly reversed cell death and the level of LC3-II increased by raloxifene. Besides, raloxifene-induced cell death was not related to cleavage of caspases-7, -9, and PARP. These results indicate that raloxifene activates autophagy-dependent cell death but not apoptosis. Interestingly, raloxifene decreased the level of intracellular adenosine triphosphate (ATP) and activated the AMPK/ULK1 pathway. However it was not suppressed the AKT/mTOR pathway. Addition of ATP decreased the phosphorylation of AMPK as well as the accumulation of LC3-II, finally attenuating raloxifene-induced cell death. Our current study demonstrates that raloxifene induces autophagy via the activation of AMPK by sensing decreases in ATP, and that the overactivation of autophagy promotes cell death and thereby mediates the anti-cancer effects of raloxifene in breast cancer cells.

• 대한임상검사과학회지
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• 제38권3호
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• pp.184-188
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• 2006

The purpose of the recovery experiment in clinical chemistry is performed to estimate proportional systematic error. We must know all measurements have some error margin in measuring analytical performance. Proportional systematic error is the type of error whose magnitude increases as the concentration of analyte increases. This error is often caused by a substance in the sample matrix that reacts with the sought for analyte and therefore competes with the analytical reagent. Recovery experiments, therefore, are used rather selectively and do not have a high priority when another analytical method is available for comparison purposes. They may still be useful to help understand the nature of any bias revealed in the comparison of kit experiments. Recovery should be expressed as a percentage because the experimental objective is to estimate proportional systematic error, which is a percentage type of error. Good recovery is 100.0%. The difference between 100 and the observed recovery(in percent) is the proportional systematic error. We calculated the amount of analyte added by multiplying the concentration of the analyte added solution by the dilution factor(mL standard)/(mL standard + mL specimen) and took the difference between the sample with addition and the sample with dilution. When making judgments on method performance, the observed that the errors should be compared to the defined allowable error. The average recovery needs to be converted to proportional error(100%/Recovery) and then compared to an analytical quality requirement expressed in percent. The results of recovery experiments were total protein(101.4%), albumin(97.4%), total bilirubin(104%), alkaline phosphatase(89.1%), aspartate aminotransferase(102.8), alanine aminotransferase(103.2), gamma glutamyl transpeptidase(97.6%), creatine kinase(105.4%), lactate dehydrogenase(95.9%), creatinine(103.1%), blood urea nitrogen(102.9%), uric acid(106.4%), total cholesterol(108.5), triglycerides(89.6%), glucose(93%), amylase(109.8), calcium(102.8), inorganic phosphorus(106.3%). We then compared the observed error to the amount of error allowable for the test. There were no items beyond the CLIA criterion for acceptable performance.

• 한국식품과학회지
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• 제41권4호
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• pp.405-412
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• 2009

본 연구는 꾸지뽕 나무 열매로부터 75 kDa의 당단백질(꾸지뽕 당단백질)을 추출한 후 꾸지뽕 당단백질의 첨가에 따른 알레르기성 염증 인자인 histamine 유리 억제능력 및 COX-2의 활성 억제 효과를 평가하였다. RBL-2H3세포를 22시간 동안 IgE로 감작시킨 후, HSA를 처리하여 histamine의 유리양을 측정한 결과 꾸지뽕 당단백질을 처리한 농도가 증가함에 따라 histamine의 유리와 COX-2의 활성 억제율은 증가하였다. 또한 꾸지뽕 당단백질의 처리는 HSA에 의해 유도된 세포내 ROS 생성량을 농도에 의존적으로 억제하였다. 한편 꾸지뽕 당단백질을 농도별로 처리하여 세포내 단백질을 추출하여 western blot을 실시한 결과 100 ${\mu}g$/mL 농도의 꾸지뽕 당단백질을 처리한 그룹에서 ERK1/2, AP-1과 COX-2의 활성 수준은 현저히 억제 되었다(p<0.05). 따라서 이러 한 결과에 미루어볼 때, 꾸지뽕 당단백질은 세포내 해독효소의 활성을 증가시킴으로써 ROS 수준을 감소시켰으므로 꾸지뽕 당단백질의 역할이 다른 천연물 유래의 당단백질과 마찬가지로 특이적인 항산화 능력을 지니고 있음을 나타내며 histamine의 유리 억제와 COX-2의 활성이 억제되었을 것으로 생각된다. 이는 꾸지뽕 당단백질이 항 알레르기 효능을 갖는 물질로써 알레르기성 비염, 아토피 등과 같은 알레르기 관련 질환의 예방 및 치료제로 사용될 수 있을 것 사료된다.

• Journal of Applied Biological Chemistry
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• 제57권2호
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• pp.103-111
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• 2014

A1E is an extract from traditional Asian medicinal plants that has therapeutic activities against cancers, metabolic disease, and other intractable conditions. However, its mechanism of action on cervical cancer has not been studied. In order to ascertain if A1E would have pronounced anti-cervical cancer effect, cervical cancer cells were incubated with A1E and apoptosis was detected by nuclear morphological changes, annexin V-FITC/PI staining, cell cycle analysis, western blotting, Reverse-transcription polymerase chain reaction, and measurement of mitochondrial membrane potential. Expression of human papiloma virus E6 and E7 oncogenes was down-regulated in A1E-treated cervical cancer cells, while p53 and retinoblastoma protein levels were enhanced. A1E also perturbed cell cycle progression at sub-G1 and altered cell cycle regulatory factors in SiHa cervical cancer cells. A1E activated apoptotic intrinsic pathway markers such as caspase-9, caspase-3 and poly ADP-ribose polymerase, and down-regulated expression of Bcl-2 and Bcl-xl. A1E induced mitochondrial membrane potential collapse and cytochrome c release, and inhibited phosphatidylinositol 3-kinase (PI3K)/Akt, key factors involved in cell survival signaling. Taken all these results, A1E induced apoptosis via activation of the intrinsic pathway and inhibition of the PI3K/Akt survival-signaling pathway in SiHa cervical cancer cells. In conclusion, A1E exerts anti-proliferative action growth inhibition on cervical cancer cells through apoptosis which demonstrates its anti-cervical cancer properties.