• KSBB Journal
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• 제21권6호
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• pp.466-473
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• 2006

본 연구에서는 췌장 베타세포의 인슐린 분비 촉진 물질로 선별된 방선균 배양액에서 유래한 YHB-2017 (genistein)의 인슐린 분비 촉진 활성의 특성을 조사하고 그 작용 기전을 밝히고자 하였다. YHB-2017는 췌장소도에서 glucose 농도가 16 mM일 때 농도 의존적으로 인슐린 분비를 대조군에 비해 2배 이상 촉진시켰으며, 5.5 mM 이하의 glucose 농도에서는 인슐린 분비 촉진 활성이 거의 없는 것으로 나타났다. MIN6 세포를 이용한 YHB-2017의 인슐린 분비 촉진 활성 특성을 분석한 결과, PKA inhibitor (H89)에 의해서 활성이 저해되었으며, 세포막의 $K_{ATP}$ channel를 배제하고 단순히 칼슘이온을 최대로 세포내로 유입시킨 조건인 diazoxide ($200\;{mu}M$)와 KCI (35 mM)를 첨가한 경우에 YHB-2017는 인슐린 분비 촉진 활성을 나타내 $K_{ATP}$ channel-independent pathway를 통한 인슐린 분비 촉진 기전을 추정할 수 있었다. 베타세포의 단백질 인산화에 대한 영향을 조사한 결과 YHB-2017는 고농도 glucose 조건에서만 PKA 기질과 cAMP response element-binding protein (CREB)의 인산화를 증가시키는 것으로 나타났고, PKC 기질의 인산화에는 영향이 없었다. 또한, YHB-2017를 18시간동안 베타세포에 처리하였으나 인슐린 유전자 발현에는 영향을 주지 않았다. 이상의 결과를 종합하여 볼 때 YHB-2017는 기존의 sulphonylurea 계열 약물과는 다른 작용 기전에 의해 췌장 베타세포에서 인슐린 분비를 촉진시키며, 그 기전은 PKA경로를 통해 amplify 신호를 활성화시키는데 관여하는 것으로 추정된다.

• 한국수정란이식학회지
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• 제33권4호
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• pp.195-203
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• 2018

Interferon-tau (IFNT) is known as a major conceptus protein that signals the process of maternal recognition of pregnancy in ruminants. Also, multiple interferon genes exist in cattle, However, molecular mechanisms of these bovine IFNT (bIFNT) genes whose expressions are limited have not been characterized. We and others have observed that expression levels of bovine subtype IFNT genes in the tissues of ruminants; thus, bIFNT1 and other new type I (bIFNTc1/c2/c3) gene co-exist during the early stages of conceptus development and non-trophoblast cells. Its genes transcription could be regulated through CDX2 and ETS2 and JUN and/or cAMP-response element binding protein (CREB)-binding protein (CREBBP) expression, a transcription factor implicated in the control of cell differentiation in the trophectoderm. Bovine ear-derived fibroblast cells, were co-transfected with luciferase reporter constructs carrying upstream (positions -1000 to +51) regions of bIFNT1 and other new type I gene and various transcription factor expression plasmids. Compared to each - 1kb-bIFNT1/c1/c2/c3-Luc increased when this constructs were co-transfected with CDX2, ETS2, JUN and/or CREBBP. Also, Its genes was had very effect on activity by CDX2, either alone or with the other transcription factors, markedly increased luciferase activity. However, the degree of transcriptional activation of the bIFNTc1 gene was not similar to that bIFNT1/c2/c3 gene by expression plasmid. Furthermore, Sequence analyses also revealed that the expression levels of bIFNT1/c2/c3 gene mRNAs expression were highest on day 17, 20 and 22 trophoblast and, Madin-Darby bovine kidney (MDBK), Bovine ear-derived fibroblast (EF), and endometrium (Endo) non-trophoblast cells. But, bIFNTc1 mRNA had not same expression level, bIFNTc1 lowest levels than those of IFNT1/c2/c3 gene in both trophoblast and non-trophoblast cells. These results demonstrate that bovine subtype bIFNT genes display differential, in the trophoblast and non-trophoblast cells.

• 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.

• 생명과학회지
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• 제29권2호
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• pp.191-197
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• 2019

파킨슨병은 운동완서, 근육경직, 진전 및 비정상적인 자세 등을 임상적 특징으로 하는 주로 운동 신경계에 영향을 주는 진행성 신경 퇴행성 질환이다. 파킨슨병은 산화 스트레스와 세포 내 신호 전달 경로의 조절 장애에 의한 뇌 흑색치밀부에서의 도파민성 신경세포의 사멸을 특징으로 한다. Quercetin의 주요 대사산물인 Quercetin-3-O-glucuronide (Q3GA)는 신경 보호 효과가 있는 것으로 보고 되어 왔다. 본 연구에서는 SH-SY5Y 세포에서 1-methyl-4-phenyl pyridinium ($MPP^+$)에 의해 유도된 신경 독성에 대한 Q3GA의 신경 보호 효과와 그 분자 조절 기전을 조사하였다. Q3GA는 $MPP^+$에 의해 유도된 세포 사멸을 유의적으로 감소시켰으며 PARP 절단을 감소시켰다. 또한, Bax/Bcl-2 비율의 감소와 함께 $MPP^+$에 의해 증가된 세포 내 ROS를 감소시켰다. Q3GA는 $MPP^+$에 의해 감소된 Akt와 CREB의 인산화를 유의적으로 회복시켰지만, ERK에는 영향을 미치지 않았다. 이 결과는 Q3GA가 ROS 생산 억제와 Akt/CREB 신호 전달 경로를 통해 $MPP^+$ 에 의해 유도된 신경 독성을 억제시킬 수 있음을 시사한다. 본 연구는 Q3GA가 파킨슨병에 대한 예방제 또는 치료제로 개발될 수 있는 가능성을 제시한다.

• BMB Reports
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• 제51권8호
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• pp.388-393
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• 2018

The activating transcription factor (ATF) 4 belongs to the ATF/CREB (cAMP Response Element Binding bZIP [Basic Leucine Zipper]) transcription factor family, and plays a central role in the UPR (Unfolded Protein Response) process in cells. The induction of ATF4 expression has previously been shown to increase the replication of HIV-1. However, the detailed mechanism underlying this effect and the factors involved in the regulation of ATF4 function are still unknown. Here, we demonstrate first that knocking out ATF4 using siRNA shows a strong negative effect on HIV-1 production, indicating that ATF4 is a functional positive cellular factor in HIV-1 production. To determine the mechanism by which ATF4 regulates the HIV-1 life cycle, we assessed the effect of the overexpression of wild type ATF4 and its various derivatives on HIV-1 LTR-mediated transcriptional activation and the production of HIV-1 particles. This effect was studied through co-transfection experiments with either reporter vectors or proviral DNA. We found that the N-terminal domains of ATF4 are involved in HIV-1 LTR-mediated transcriptional activation, and thus in HIV-1 production.

• Biomolecules & Therapeutics
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• 제18권1호
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• pp.39-47
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• 2010

Brain-derived neurotrophic factor (BDNF) is a neurotrophic factor involved in neuronal differentiation, plasticity, survival and regeneration. BDNF draws massive attention mainly due to the potential as a therapeutic target in neurological diseases such as depression and Alzheimer's disease. In a primary screening for the natural compounds enhancing BDNF release from cultured rat primary cortical neuron, we found that compounds such as baicalein, tanshinone IIa, cinnamic acid, epiberberine, genistein and wogonin among many others increased BDNF release. All the compounds at $0.1{\mu}M$ of concentration barely showed stimulatory effect on BDNF induction, however, their combination (mixture 1; baicalein, tanshinone IIa and cinnamic acid, mixture 2; epiberberine, genistein and wogonin) showed synergistic increase in BDNF release as well as mRNA and protein expression. The level of BDNF expression was comparable to the maximum BDNF stimulation attainable by a positive control oroxylin A ($20{\mu}M$) without cell toxicity as determined by MTT analysis. Both mixtures synergistically increased the phosphorylation of extracellular signal-regulated kinase (ERK) as well as cAMP response element binding protein (CREB), an immediate and essential regulator of BDNF expression. Similar to these results, mixture of these compounds synergistically inhibited the up-regulation of inducible nitric oxide synthase (iNOS) induced by lipopolysaccharide treatments in rat primary astrocytes. These results suggest that the combinatorial treatment of natural compounds in lower concentration might be a useful strategy to obtain sufficient BDNF stimulation in neurological disease condition such as depression, while minimizing potential side effects and toxicity of higher concentration of a single compound.

• 생명과학회지
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• 제29권11호
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• pp.1200-1207
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• 2019

Loganin은 Corni fructus의 주요 iridoid glycoside이며 항염증, 항당뇨 그리고 뇌신경보호 효과 등이 보고되었다. 본 연구에서는 ${\alpha}-MSH$와 IBMX처리된 B16F10세포에서 loganin의 melanogenesis억제효과의 신호전달 경로를 조사하였다. Loganin의 미백 활성을 확인하기 위해 B16F10세포에서 $1{\mu}m$에서 $20{\mu}m$사이의 농도를 처리하여 세포독성 실험을 수행한 결과 최대 $20{\mu}m$농도에서 독성을 나타내지 않았다. 또한 loganin은 ${\alpha}-MSH$와 IBMX처리된 B16F10세포에서 농도-의존적으로 멜라닌 생성을 감소시키는 것을 확인하였다. 또한 loganin의 멜라닌 생성을 억제하는 신호전달 경로를 Western blotting을 실시하여 조사하였다. Western blot결과에 따르면 loganin은 ${\alpha}-MSH$와 IBMX 처리된 B16F10세포에서 증가된 CREB인산화(Ser133)와 MITF 발현 및 tyrosinase의 유전자 발현을 감소시켰고 ERK의 인산화를 증가시켜 melanin 생성을 억제하였다. 결론적으로 loganin은 ${\alpha}-MSH$와 IBMX에 의해 유도된 과도한 멜라닌 합성을 CREB인산화와 MITF 및 tyrosinase의 유전자 발현을 억제하고 ERK의 활성화를 통해 멜라닌 합성을 감소됨을 확인하였다. 따라서 loganin은 과색소 침착과 관련된 피부질환의 보호제로서 활용될 가능성을 가지는 것으로 사료된다.

• Biomolecules & Therapeutics
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• 제20권1호
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• pp.27-35
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• 2012

Oroxylin A is a flavone isolated from a medicinal herb reported to be effective in reducing the inflammatory and oxidative stresses. It also modulates the production of brain derived neurotrophic factor (BDNF) in cortical neurons by the transactivation of cAMP response element-binding protein (CREB). As a neurotrophin, BDNF plays roles in neuronal development, differentiation, synaptogenesis, and neural protection from the harmful stimuli. Adenosine $A2_A$ receptor colocalized with BDNF in brain and the functional interaction between $A2_A$ receptor stimulation and BDNF action has been suggested. In this study, we investigated the possibility that oroxylin A modulates BDNF production in cortical neuron through the regulation of $A2_A$ receptor system. As expected, CGS21680 ($A2_A$ receptor agonist) induced BDNF expression and release, however, an antagonist, ZM241385, prevented oroxylin A-induced increase in BDNF production. Oroxylin A activated the PI3K-Akt-GSK-$3{\beta}$ signaling pathway, which is inhibited by ZM241385 and the blockade of the signaling pathway abolished the increase in BDNF production. The physiological roles of oroxylin A-induced BDNF production were demonstrated by the increased neurite extension as well as synapse formation from neurons. Overall, oroxylin A might regulate BDNF production in cortical neuron through $A2_A$ receptor stimulation, which promotes cellular survival, synapse formation and neurite extension.

• 한국미생물·생명공학회지
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• 제47권1호
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• pp.148-157
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• 2019

개망초의 항산화능 측정으로 전자공여능을 측정한 결과 농도 의존적으로 활성이 증가하여 $500{\mu}g/ml$에서 82%의 높은 전자공여능을 나타내었다. $ABTS^+$ 라디칼 소거능 측정 결과 농도가 증가함에 따라 활성이 증가하였으며, $500{\mu}g/ml$에서 87% 이상의 활성을 나타내었다. Tyrosinase 저해 활성 측정결과 개망초 에탄올 추출물이 $100{\mu}g/ml$에서 69%의 효과를 나타내었다. 농도가 증가함에 따라 억제활성이 증가하는 것을 확인할 수 있었고, $100{\mu}g/ml$에서 32.2%의 효과를 나타내었다. 개망초 추출물에 대한 수렴효과를 측정한 결과 농도의존적으로 활성이 증가하였으며, $100{\mu}g/ml$에서 80%이상의 우수한 수렴효과를 확인할 수 있었다. 세포 생존율을 MTT 분석법을 통해 확인한 결과 농도 구간이 $100{\mu}g/ml$ 일 때 96%의 생존율을 보였으며, 따라서 관련 실험을 세포생존율이 100%에 가까운 25, 50, $100{\mu}g/ml$에서 진행하였다. B16F10 세포에 개망초 에탄올 추출물을 처리한 결과 MITF, TRP-2의 단백질 발현양이 감소하는 것을 확인할 수 있었으며, TRP-1과 tyrosinase 발현양이 크게 감소하는 것을 확인할 수 있었다. 상위 단계 유전자인 ERK와 CREB의 발현양은 미비했으나, 인산화된 ERK와 인산화된 CREB에서 농도가 증가함에 따라 단백질 발현양이 감소하는 것을 확인할 수 있었다. 개망초 에탄올 추출물을 25, 50, $100{\mu}g/ml$의 농도 별로 처리하였으며 MITF, TRP-1, TRP-2, tyrosinase의 mRNA 발현 측정 결과 농도가 증가함에 따라서 mRNA 발현을 억제하는 것을 확인할 수 있었다. 따라서 항산화 및 멜라닌 생합성에 관여하는 그 하위 유전자 및 상위 유전자의 발현을 저해하여 멜라닌 생성을 억제하는 것으로 추측되고 그에 따라 우리나라 전역에서 재배가 가능하고 국화과에 속하는 신귀화식물 개망초를 기능성 천연 미백소재로써 이용 가능성을 확인하였다.

• 대한본초학회지
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• 제30권1호
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• pp.67-75
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• 2015

Objectives : The aim of this study is to examine the neuroprotective effect of wheat bran extract (WBE) against ${\beta}$-amyloid ($A{\beta}$)-induced apoptotic cell death in SH-SY5Y human neuroblastoma cells and memory impairment in triple transgenic animal model's of Alzheimer's disease (3xTg AD mice). Methods : In SH-SY5Y cells, MTT assay and TUNEL staining were conducted to evaluate the protective effect of WBE against $A{\beta}_{25-35}$-induced neurotoxicity and apoptosis. Alterations in mitochondrial transmembrane potential (MMP), expression of proapoptotic Bax and antiapoptotic Bcl-2 proteins, cleavage of PARP, and brain-derived neurotrophic factor (BDNF) levels were analyzed to elucidate the neuroprotective mechanism of WBE. To further investigate the memory enhancing effect of WBE, Morris water maze test was performed in 3xTg AD mice. Results : In SH-SY5Y cells, WBE protected against $A{\beta}_{25-35}$-caused cytotoxicity and apoptosis as shown by the restoration of cell viability in MTT assay and inhibition of DNA fragmentation in TUNEL staining. $A{\beta}_{25-35}$-induced apoptotic signals such as dissipation of MMP, decreased Bcl-2/Bax ratio, and cleavage of PARP were suppressed by WBE. Moreover, WBE up-regulated the protein levels of BDNF, which seemed to be mediated by activation of cAMP response element-binding protein (CREB). In 3xTg AD mice, oral administration of WBE attenuated learning and memory deficit as verified by reduced mean escape latency in water maze test. Conclusions : WBE protects neuronal cells from $A{\beta}_{25-35}$-induced apoptotic cell death and restores learning and memory impairments in 3xTg AD mice. These findings suggest that WBE exhibit neuroprotective potential for the management of AD.