• 생명과학회지
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• 제31권8호
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• pp.729-735
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• 2021

제 2 형 당뇨병은 조직의 포도당 흡수 능력에 이상이 있을 때 발생하며, 인슐린에 의한 포도당 섭취와 신진대사는 혈당을 유지하는 기본 활동이며 포도당 섭취는 인슐린이 세포 표면의 수용체에 결합하여 시작되는 다양한 신호 단계를 거친다. 본 연구는 Ecklonia cava에서 분리된 활성 화합물 인 2,7-phloroglucinol-6,6-bieckol이 3T3-L1 지방 세포에서 인슐린 신호전달체계에 따른 포도당 흡수 증가에 미치는 영향에 대한 것이다. 2,7-phloroglucinol-6,6-bieckol 은 3T3-L1 지방 세포에서 농도의존적으로 GLUT4의 발현을 증가시켜 원형질막에서의 glucose uptake 를 증가시켰다. 이는 인슐린 신호 전달 경로에서 2,7-phloroglucinol-6,6-bieckol 에 의한 IRS-1, AKT의 인산화 및 PI3K 활성화에 의한 것이다. PHB는 또한 AMPK 인산화와 활성화를 자극했다. 2,7-phloroglucinol-6,6-bieckol에 의한 PI3K/AKT 및 AMPK 경로의 인산화 및 활성화는 wortmannin (PI3K 억제제) 및 화합물 C (AMPK 억제제)를 사용하여 확인하였다. 본 연구에서 2,7-phloroglucinol-6,6-bieckol 이 3T3-L1 지방 세포에서 PI3K 및 AMPK 경로를 통해 원형질막으로의 GLUT4 전위를 촉진함으로써 포도당 흡수를 증가시킬 수 있음을 나타내었다. 이러한 결과는 2,7-phloroglucinol-6,6-bieckol 가 인슐린 감수성을 개선하는 데 도움이 될 수 있음을 시사한다.

• 대한임상검사과학회지
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• 제49권2호
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• pp.99-107
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• 2017

진균 속에 속하는 종인 Cordyceps는 중국의 전통약제로서, 그 유효성분인 cordycepin이 혈소판 응집에 관여한다는 보고가 있지만 phosphoprotein 조절에 관련된 연구는 미흡하다. 본 연구에서는, cordycepin이 fibrinogen binding에 관여한다고 알려진 PI3k/Akt와 $TXA_2$ 분비 및 과립방출에 관여한다고 알려진 p38와 같은 phosphoprotein의 인산화를 어떻게 조절하며 혈소판응집을 억제시키는지 규명하고자 하였다. 그 결과, cordycepin가 $261.1{\mu}M$의 $IC_{50}$으로 collagen이 유도한 혈소판 응집을 강력하게 억제하였고, PI3K와 Akt의 인산화를 감소시키며 ${\alpha}IIb/{\beta}_3$에 대한 fibrinogen 결합을 농도의존적으로 억제하였다. 또한, cordycepin은 collagen이 촉진시킨 p38의 인산화를 억제함으로써, 과립방출의 지표인 ATP 과 serotonin의 방출을 억제하였고 COX-1과 TXAS의 활성 및 $PLC-{\gamma}_2$ 인산화에 대한 영향없이 $TXA_2$ 생성량을 감소시켰다. 따라서, cordycepin은 PI3K/Akt, p38와 같은 phosphoprotein의 인산화를 억제함으로써 혈소판 응집억제를 나타내는 항혈전 치료 및 예방약물로서 유용한 가치가 있다고 여겨진다.

• 동의생리병리학회지
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• 제21권1호
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• pp.86-92
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• 2007

Hibiscus sabdariffa L., a tropical beverage material, is used commonly as in folk medicine against hypertension, pyrexia, inflammation, liver disorders, and obesity. However, the mechanism by which Hibiscus sabdariffa L. modulates adipogenic differentiation is remained to be elusive. This report was designed to investigate the inhibitory effect of Hibiscus extract on insulin signaling pathway during adipocyte differentiation in 3T3-L1 preadipocytes. 3T3-L1 preadipocytes were differentiated with isobutylmethylxanthine, dexamethasone, and insulin (MDI) and followed by the addition of Hibiscus extract. Treatment with Hibiscus resulted in a decrease of lipid droplet accumulation, which was suppressed by PI-3 kinase inhibitor wortmannin in 3T3-L1 preadipocytes. Also, Hibiscus extract markedly attenuated the mRNA expression of adipogenic transcriptional factor PPAR${\gamma}$ and adipogenic hormon Leptin during adipogenesis. However, it did not affect the expression of adiponectin in 3T3-L1 preadipocytes differentiated with MDI mixture. Furthermore, Adipogenic differentiation by MDI mixture increased the phosphorylation and expression of PI3-Kinase and Akt in 3T3 preadipocytes, which was markedly suppressed by Hibiscus extract treatment. Taken together, our results suggest that Hibiscus extract suppressed the adipogenic differentiation of 3T3 preadipocytes through activation of PI3-Kinase and Akt signaling pathway.

• Molecules and Cells
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• 제42권6호
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• pp.448-459
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• 2019

The phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) signaling pathway is a promising target for gastric cancer (GC) treatment; however the efficacy of PI3K/mTOR dual inhibitors in GC has not yet been maximized. Additionally, the effect of autophagy regulation by PI3K/mTOR dual inhibitors has not been clearly elucidated in GC treatment. We aimed to show that our newly developed PI3K/mTOR dual inhibitor, CMG002, when combined with an autophagy inhibitor, chloroquine (CQ), potently induces effective cancer cell death in Epstein-Barr virus (EBV)-associated gastric cancer (EBVaGC) cells, where both the PI3K/AKT/mTOR and autophagy pathways play important roles in disease pathogenesis. EBV- and mock-infected AGS and NUGC3 GC cell lines were treated with CMG002 +/- CQ. PI3K/AKT/mTOR signaling pathway mediators, cellular apoptosis and autophagy markers were confirmed by Western blot assay. Cell viability was assessed using the Cell Counting Kit-8 (CCK-8) assay. CMG002 effectively blocked the PI3K/AKT/mTOR pathway by markedly decreasing phosphorylation of AKT and its downstream mediator S6. CMG002 induced G0/G1 cell cycle arrest and enhanced apoptotic cell death in AGS and NUGC3 cells, particularly EBV-infected cells compared with mock-infected cells, as confirmed by flow cytometric analyses and TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) assays. The combination of CMG002 plus CQ synergistically increased apoptotic cell death in EBV-infected GC cell lines when compared with CMG002 alone (P < 0.05). Our results suggest that the new PI3K/mTOR dual inhibitor, CMG002, when used in combination with the autophagy inhibitor, CQ, provides enhanced therapeutic efficacy against EBVaGC.

• 생명과학회지
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• 제32권10호
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• pp.762-770
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• 2022

제 2형 당뇨병은 고혈당을 특징으로 하는 만성 대사성 질환으로 인슐린 민감성및 저항성을 개선하여 세포속으로 포도당 흡수를 촉진시킴으로서 완화될 수 있다. 본 연구는 triterpenoid 화합물인 betulinic acid가 3T3-L1 지방세포에서 인슐린 신호전달체계를 개선하여 포도당 흡수를 촉진시키는지를 조사하고 그 작용기전을 규명하였다. Betulinic acid는 3T3-L1 지방세포에서 농도의존적으로 포도당 흡수를 유의하게 증가시켰으며, 이는 PM-GLUT4의 발현 증가와 관련이 있음을 관찰하였다. Betulinic acid는 인슐린 신호전달 경로에서 PI3K의 활성화 및 IRS-1tyr, Akt의 인산화를 대조군에 비해 유의하게 증가시켰다. 또한 AMPK의 활성화를 나타내는 pAMPK와 AMPK 하위인자인 pACC의 수준을 유의하게 증가시켰다. Betulinic acid에 의한 PI3K 및 AMPK 경로의 활성화를 증명하기 위해, PI3K 억제제(Wortmannin)와 AMPK의 억제제(Compound C)를 사용하여 이들 처리에 의한 포도당 흡수능과 PM-GLUT4의 발현을 측정한 결과 이들의 발현이 유의하게 저해되었다. 본 연구에서 betulinic acid는 3T3-L1 지방세포에서 PI3K 및 AMPK 경로의 활성화를 통해 세포막으로 포도당 수송체인 GLUT4 전위를 촉진시키고 포도당 흡수를 증가시킬 수 있음을 나타내었다. 이러한 결과는 betulinic acid가 인슐린 민감성을 증진시키고 고혈당을 완화하는데 도움이 될 수 있음을 시사한다.

• The Korean Journal of Physiology and Pharmacology
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• 제25권2호
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• pp.147-157
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• 2021

Coronary microembolization (CME) is associated with cardiomyocyte apoptosis and cardiac dysfunction. Puerarin confers protection against multiple cardiovascular diseases, but its effects and specific mechanisms on CME are not fully known. Hence, our study investigated whether puerarin pretreatment could alleviate cardiomyocyte apoptosis and improve cardiac function following CME. The molecular mechanism associated was also explored. A total of 48 Sprague-Dawley rats were randomly divided into CME, CME + Puerarin (CME + Pue), sham, and sham + Puerarin (sham + Pue) groups (with 12 rats per group). A CME model was established in CME and CME + Pue groups by injecting 42 ㎛ microspheres into the left ventricle of rats. Rats in the CME + Pue and sham + Pue groups were intraperitoneally injected with puerarin at 120 mg/kg daily for 7 days before operation. Cardiac function, myocardial histopathology, and cardiomyocyte apoptosis index were determined via cardiac ultrasound, hematoxylin-eosin (H&E) and hematoxylin-basic fuchsin-picric acid (HBFP) stainings, and TdT-mediated dUTP nick-end labeling (TUNEL) staining, respectively. Western blotting was used to measure protein expression related to the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/glycogen synthase kinase-3β (GSK-3β) pathway. We found that, puerarin significantly ameliorated cardiac dysfunction after CME, attenuated myocardial infarct size, and reduced myocardial apoptotic index. Besides, puerarin inhibited cardiomyocyte apoptosis, as revealed by decreased Bax and cleaved caspase-3, and up-regulated Bcl-2 and PI3K/Akt/GSK-3β pathway related proteins. Collectively, puerarin can inhibit cardiomyocyte apoptosis and thus attenuate myocardial injury caused by CME. Mechanistically, these effects may be achieved through activation of the PI3K/Akt/GSK-3β pathway.

• 대한본초학회지
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• 제39권1호
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• pp.23-29
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• 2024

Objectives : Polyporus umbellatus is a medicinal mushroom that has been used for over thousands years in Chinese medicine as a powerful diuretic to relieve fluid retention and edema. Dermal papilla is located at the bottom of the hair follicle and connected to the blood vessels where it gets the nutrients and oxygen to nurture hair follicle. This study examined the mechanism through which the ethanol extract of Polyporus umbellatus (EPU) promoted the proliferation of human dermal papilla cells (HHDPCs). Methods : To estimate the proliferative effects of EPU on HHDPCs, cell viability was estimated by thiazolyl blue tetrazolium bromide (MTT) assay. Western blotting was used to investgate the activation of ERK, phosphoinositide 3-kinase (PI3K)/Akt, β-catenin, GSK-3β and heme oxygenase-1 (HO-1). Cells were treated with inhibitors of ERK and Akt prior to EPU treatment. Results : EPU promoted the proliferation of HHDPCs and the phosphorylation of ERK and Akt in dose dependent manner. However, the proliferative effect of EPU on HHDPCs was inhibited by pre-treatment of ERK inhibitor (PD98059) and Akt inhibitor (LY294002). Furthermore, EPU respectively stimulated the protein expression of β-catenin and phosphorylated GSK-3β. EPU significantly increased the protein expression levels of proliferation and cytoprotection related genes such as Bcl-2, SIRT-1, and HO-1 in cells. Conclusion : This results suggest that EPU promoted the proliferation of HHDPCs via activating PI3K/Akt and Wnt/β-catenin signaling pathway in HHDPCs.

• 생명과학회지
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• 제20권11호
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• pp.1617-1624
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• 2010

$\alpha$-MSH는 세포내 cAMP를 증폭시켜 멜라닌세포의 증식과 색소 증가에 관여한다. 본 연구에서는 $\alpha$-MSH로 자극한 B16F10 세포에서 세신추출물의 hypopigmenting 효과를 조사하고 그 억제기전에 대하여 조사하였다. 세신추출물은 $\alpha$-MSH에 의해 유도된 tyrosinase 활성과 멜라닌생성을 효과적으로 억제시켰으며, 이는 tyrosinase 발현을 조절하는 전사인자인 MITF의 발현억제와 연관성이 있었다. 즉 세신추출물은 MEK/ERK와 PI3K/Akt의 활성화를 통하여 MITF를 조절함으로서 $\alpha$-MSH에 의해 유도되는 tyrosinase, TRP-1, Dct 등 멜라닌생성관련 단백질을 억제함으로서 멜라닌생성을 저해하는 것으로 사료된다.

• The Korean Journal of Physiology and Pharmacology
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• 제4권6호
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• pp.487-496
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• 2000

Insulin stimulates glucose transport in muscle and fat cells by promoting the translocation of glucose transporter (GLUT4) to the cell surface. Phosphatidylinositide 3-kinase (PI3-kinase) has been implicated in this process. However, the involvement of protein kinase B (PKB)/Akt and $PKC-{\zeta}$, those are known as the downstream target of PI3-kinase in regulation of GLUT4 translocation, is not known yet. An interesting possibility is that these protein kinases phosphorylate GLUT4 directly in this process. In the present study, $PKB-{\alpha}$ and $PKC-{\zeta}$ were added exogenously to GLUT4-containing vesicles purified from low density microsome (LDM) of the rat adipocytes by immunoadsorption and immunoprecipitation for direct phosphorylation of GLUT4. Interestingly GLUT4 was phosphorylated by $PKC-{\zeta}$ and its phosphorylation was increased in insulin stimulated state but GLUT4 was not phosphorylated by $PKB-{\alpha}.$ However, the GST-fusion proteins, GLUT4 C-terminal cytoplasmic domain (GLUT4C) and the entire major GLUT4 cytoplasmic domain corresponding to N-terminus, central loop and C-terminus in tandem (GLUT4NLC) were phosphorylated by both $PKB-{\alpha}$ and $PKC-{\zeta}.$ The immunoblots of $PKC-{\zeta}$ and $PKB-{\alpha}$ antibodies with GLUT4-containing vesicles preparation showed that $PKC-{\zeta}$ was co-localized with the vesicles but not $PKB-{\alpha}.$ From the above results, it is clear that $PKC-{\zeta}$ interacts with GLUT4-containing vesicles and it phosphorylates GLUT4 protein directly but $PKB-{\alpha}$ does not interact with GLUT4, suggesting that insulin-elicited signals that pass through PI3-kinase subsequently diverge into two independent pathways, an Akt pathway and a $PKC-{\zeta}$ pathway, and that later pathway contributes, at least in part, insulin stimulation of GLUT4 translocation in adipocytes via a direct GLUT4 phosphorylation.

• Fisheries and Aquatic Sciences
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• 제26권2호
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• pp.133-144
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• 2023

Auranofin is a US Food and Drug Administration (FDA)-approved anti-arthritis medication that functions as a thioredoxin reductase inhibitor. Spermidine, a polyamine present in marine algae, can exert various physiological functions. Herein, we examined the synergistic anticancer activity of auranofin and spermidine in hepatocellular carcinoma (HCC). Combined treatment with auranofin and spermidine suppressed cell viability more efficiently than either treatment alone in HCC Hep3B cells. The isobologram plotted by calculating the half maximal inhibitory concentration (IC₅₀) values of each drug indicated that the two drugs exhibited a synergistic effect. Based on the analysis of annexin V and cell cycle distribution, auranofin and spermidine markedly induced apoptosis in Hep3B cells. Moreover, auranofin and spermidine increased mitochondria-mediated apoptosis by promoting mitochondrial membrane potential (Δψm) loss. Auranofin and spermidine significantly increased reactive oxygen species (ROS) production in Hep3B cells, and the blocking ROS suppressed apoptosis induced by spermidine and auranofin. In addition, auranofin and spermidine reduced the expression of phosphorylated phosphatidylinositol-3 kinase (PI3K) and protein kinase B (Akt), and PI3K inhibitor accelerated auranofin- and spermidine-induced apoptosis. Using ROS scavenger and PI3K inhibitor, we revealed that ROS acts upstream of auranofin- and spermidine-induced apoptosis. Collectively, our study suggests that combination treatment with auranofin and spermidine could afford synergistic anticancer activity via ROS overproduction and reduced PI3K/Akt signaling pathway.