• Journal of Microbiology and Biotechnology
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• v.22 no.6
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• pp.806-813
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• 2012

Adipocyte differentiation is strongly associated with obesity, which causes metabolic disorders. In this study, we investigated the inhibitory effects of widdrol on 3T3-L1 preadipocyte growth and differentiation. Widdrol decreased lipid droplet accumulation and down-regulated adipogenic transcription factors such as C/$EBP{\alpha}$, C/$EBP{\beta}$, and $PPAR{\gamma}$. Widdrol blocked preadipocyte proliferation and differentiation through the inhibition of mitotic clonal expansion, which was accompanied by the failure of degradation of p21, a cyclin-dependent kinase inhibitor. Cell-cycle analysis clearly indicated that widdrol actively induces cell-cycle arrest at the G1-S phage transition, causing cells to remain in the preadipocyte state. Moreover, widdrol increased p21 expression and inhibited Rb phosphorylation in preadipocyte incubated in a hormone medium. Therefore, these findings clearly suggest that widdrol blocks preadipocyte growth and differentiation through the inhibition of mitotic clonal expansion by p21-and Rb-dependent G1 arrest and can be developed as a potent anti-adipogenic agent for reducing obesity.

• Journal of Life Science
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• v.29 no.4
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• pp.447-454
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• 2019

Fat accumulation in adipocytes occurs through the process of adipogenesis in which preadipocytes differentiate into adipocytes. Obesity is a metabolic disorder caused by excessive accumulation of fat in the body, which increases the incidence of cardiovascular diseases, hypertension, type 2 diabetes, hyperlipidemia, and various cancers. Recently, inhibition of adipocyte differentiation was shown to be a potential antiobesity strategy. In this study, the inhibitory effect of dichloromethane fractions from Illicium verum Hooker fil. water extract on the differentiation of 3T3-L1 preadipocytes to adipocytes was investigated. Dichloromethane fractions from I. verum Hooker fil. significantly inhibited adipocyte differentiation when applied during the adipocyte differentiation process, as assessed by measuring fat accumulation using Oil-red O staining. In addition, dichloromethane fractions from I. verum Hooker fil. reduced important adipogenic transcription factors, such as CCAAT/enhancer binding protein ${\alpha}$ ($C/EBP{\alpha}$), $C/EBP{\beta}$, and peroxisome proliferator activated receptor ${\gamma}$ ($PPAR{\gamma}$). The expression of FAS and LPL, which are terminal differentiation markers of mature adipocytes, was also reduced in the 3T3-L1 adipocytes treated with dichloromethane fractions from I. verum Hooker fil. In addition, the treatment significantly inhibited mitotic clonal expansion, which is essential for adipocyte differentiation, by arresting the G1 phase of the cell cycle. Taken together, these results suggest that dichloromethane fractions from I. verum Hooker fil. may be a natural material with antiobesity effects.

• Microbiology and Biotechnology Letters
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• v.44 no.1
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• pp.89-97
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• 2016

Obesity is caused by excess accumulation of body fat and contributes to various pathological disorders such as diabetes, hypertension, cardiovascular disease, and cancer. In this study, we investigated the effect of a 30% ethanol extract of Fructus Rosae laevigata (RLE) on adipogenesis in 3T3-L1 adipocytes, measured by triglyceride accumulation and expression of adipogenesis-related transcription factors during differentiation of pre-adipocytes into adipocytes. RLE decreased the intracellular triglyceride contents (assessed by Oil Red-O staining) in a dose-dependent manner. It also downregulated the expression of adipogenic transcription factors and inhibited cell proliferation during the mitotic clonal expansion phase of adipocyte differentiation by inducing G1 phase arrest. We investigated the alterations in the levels of G1 phase arrest-related proteins. The expression of p21 protein significantly increased, while the levels of Cyclin E, Cdk2, and phospho-Rb decreased in a dose-dependent manner in 3T3-L1 cells treated with RLE. These results suggest that RLE inhibits the differentiation of 3T3-L1 adipocytes by suppressing the expression of adipogenic transcription factors and inducing G1 phase arrest in the early stages of adipocyte differentiation.

• Journal of Life Science
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• v.24 no.2
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• pp.137-147
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• 2014

Cortex ulmi pumilae, the cortex of Ulmus davidiana var. japonica, has been used in traditional folk medicine for its anti-inflammatory effect. Although its various bioactivities such as anti-inflammatory, anti-microbial, and anti-cancer, have been reported, the anti-adipogenic activity of cortex ulmi pumilae remains unclarified. In the present study, we investigated the effect of cortex ulmi pumilae extract on adipocyte differentiation in 3T3-L1 preadipocytes. Treatment with cortex ulmi pumilae extract significantly reduced the formation of lipid droplets and triglyceride content in a dose-dependent manner; this is associated with an inhibition of the adipogenic transcription factors, CCAAT/enhancer binding protein ${\alpha}$ ($C/EBP{\alpha}$), $C/EBP{\beta}$, and peroxisome proliferator-activated receptor ${\gamma}$ ($PPAR{\gamma}$). In addition, cortex ulmi pumilae extract treatment during the early stage of adipogenesis showed more efficient anti-adipogenic activity than treatment during other stages of adipogenesis. Cortex ulmi pumilae extract also inhibited cell proliferation and induced G1 arrest of 3T3-L1 cells in the early stage of adipogenesis. This was associated with upregulated expression of Cdk inhibitor p21 and downregulated expression of cyclin E and phospho-Rb, indicating that cortex ulmi pumilae extract blocks mitotic clonal expansion by cell cycle regulation. Taken together, these results suggest that cortex ulmi pumilae extract possesses anti-adipogenic activity through the inhibition of adipocyte differentiation by blocking mitotic clonal expansion.

• Journal of Life Science
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• v.24 no.10
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• pp.1085-1091
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• 2014

The purpose of this study was to determine the effect of selenate on adipocyte differentiation and to identify genes involved in the modulation of adipogenesis in 3T3-L1 cells. To test the effect of selenate on adipocyte differentiation, adipogenesis was induced in cells using various concentrations ($0-100{\mu}M$) of selenate. Various phases of adipogenesis were induced: postconfluent (PC), early phase (EP, d0-d2), postmitotic growth arrest (PM, d2-d4), and all period (AP). The PC cells exposed to selenate for 24 h displayed dose-dependent inhibition of intracellular lipid droplet accumulation on day 6 of adipogenesis. Two days of selenate treatment at EP or AP inhibited adipogenesis, with an approximately 20-80% reduction in lipid accumulation compared to that of a control (p<0.05). When preadipocytes were exposed to selenate during the PM period, the antiadipogenic effect of selenate was attenuated. Two types of selenoprotein genes (Seps1 and Sepp1) were up-regulated by the selenate treatment during mitotic clonal expansion, whereas these genes were down-regulated during PM growth arrest (p<0.05). The findings demonstrate the antiadipogenic function of selenate and the possible involvement of Sepp1 and Seps1 genes in selenate-inhibited adipogenesis in 3T3-L1 cells.

• Journal of Life Science
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• v.22 no.12
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• pp.1688-1696
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• 2012

Oenanthe javanica has been used as a food source and also in traditional folk medicine for its detoxifying properties and anti-microbial effects since ancient times. In this study, we evaluated the effect and mechanism of O. javanica seed methanol extract (OJSE) on adipocyte differentiation by 3T3-L1 preadipocytes. Under non-toxic conditions, OJSE treatment resulted in a dose-dependent inhibition of lipid droplet generation and triglyceride accumulation by suppressing adipocyte differentiation, which are associated with the decreased expression of key proadipogenic transcription factors including CCAAR/enhancer binding protein ${\alpha}$, ${\beta}$ ($C/EBP{\alpha}$, $C/EBP{\beta}$) and peroxisome proliferator-activated receptor ${\gamma}$ ($PPAR{\gamma}$). OJSE also significantly inhibited proliferation and differentiation of 3T3-L1 preadipocytes through G1-phase arrest, indicating that OJSE blocked mitotic clonal expansion during adipocyte differentiation. Investigation of the alteration of G1 phase arrest-related proteins indicated a dose-dependent increase in the expression of p21 and reduction in expression of cyclin E, Cdk2, E2F-1 and phospho-Rb by OSJE. Taken together, these results suggest that OJSE inhibits adipocyte differentiation by blocking the mitotic clonal expansion, which is accompanied by preadipocyte cell cycle arrest.

• IMMUNE NETWORK
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• v.13 no.3
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• pp.86-93
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• 2013

In the present study, we investigated if priming of autoreactive $CD8^+T$ cells would be inhibited by competitive peptides for major histocompatibility complex (MHC) class I binding. We used a mouse model of vitiligo which is induced by immunization of $K^b$-binding tyrosinase-related protein 2 (TRP2)-180 peptide. Competitive peptides for $K^b$ binding inhibited IFN-${\gamma}$production and proliferation of TRP2-180-specific $CD8^+T$ cells upon ex vivo peptide restimulation, while other MHC class I-binding peptides did not. In mice, the capability of inhibition was influenced by T-cell immunogenicity of the competitive peptides. The competitive peptide with a high T-cell immunogenicity efficiently inhibited priming of TRP2-180-specific $CD8^+T$ cells in vivo, whereas the competitive peptide with a low T-cell immunogenicity did not. Taken together, the inhibition of priming of autoreactive $CD8^+T$ cells depends on not only competition of peptides for MHC class I binding but also competitive peptide-specific $CD8^+T$ cells, suggesting that clonal expansion of autoreactive T cells would be affected by expansion of competitive peptide-specific T cells. This result provides new insights into the development of competitive peptides-based therapy for the treatment of autoimmune diseases.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.1
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• pp.111-118
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• 2017

Objective: Adipose tissue plays a key role in the development of obesity and diabetes. We previously reported that lignosulfonic acid suppresses the rise in blood glucose levels through the inhibition of ${\alpha}$-glucosidase activity and intestinal glucose absorption. The purpose of this study is to examine further biological activities of lignosulfonic acid. Methods: In this study, we examined the effect of lignosulfonic acid on differentiation of 3T3-L1 cells. Results: While lignosulfonic acid inhibited proliferation (mitotic clonal expansion) after induction of differentiation, lignosulfonic acid significantly increased the size of accumulated lipid droplets in the cells. Semi-quantitative reverse transcription polymerase chain reaction analysis showed that lignosulfonic acid increased the expression of the adipogenic transcription factor, peroxisome proliferator-activated receptor gamma ($PPAR{\gamma}$), leading to increased glucose transporter 4 (Glut-4) expression and 2-deoxyglucose uptake in differentiated 3T3-L1 cells. Additionally, feeding lignosulfonic acid to diabetic KK-Ay mice suppressed increase of blood glucose level. Conclusion: Lignosulfonic acid may be useful as a functional anti-diabetic component of food.

• Natural Product Sciences
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• v.17 no.4
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• pp.273-278
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• 2011

In this study, the effects of a methanol (MeOH) extract of Carduus crispus L. (Asteraceae) on adipogenesis was investigated in 3T3-L1 cells. To differentiate preadipocytes to adipocytes, confluent 3T3-L1 preadipocytes were treated with a hormone mixture, which included isobutylmethylxanthine, dexamethasone, and insulin (MDI). The methanol extract of C. crispus significantly decreased fat accumulation by inhibiting adipogenic signal transcriptional factors in MDI-induced 3T3-L1 cells in a dose-dependent manner. In MTT assays and on PI-staining, methanol extract of C. crispus inhibited the proliferation of 3T3-L1 cells during mitotic clonal expansion (MCE). The anti-adipogenic effect of the Carduus extract seemed to be associated with the upregulation of extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK) pathways within the first 2 days after MDI treatment. These results suggest that methanol extract of C. crispus might be beneficial for the treatment of obesity.

• Journal of Life Science
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• v.21 no.9
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• pp.1346-1353
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• 2011

Sophora tonkinensis Gapnep has been used as a traditional herbal medicine in oriental regions since ancient times. In this study, the effect and mechanism of the MeOH extract of Sophora tonkinensis Gapnep (STME) on adipocite differentiation and adipogenesis in 3T3-L1 preadipocites were investigated. Treatment with STME in the concentration range of 0-200 ${\mu}g$/ml significantly inhibited the differentiation of 3T3-L1 preadipocites in a dose-dependent manner, as determined by a decrease in intracellular lipid droplets and lipid contents measured by Oil Red O staining. In association with the inhibitory effect of lipid accumulation, the expressions of the proteins concerned with adipogenesis in 3T3-L1 preadipocites were also investigated. Treatment with STME reduced the expressions of peroxisome proliferator-activated receptor ${\gamma}$ (PPAR${\gamma}$), cytidine-cytidine-adenosine-adenosine-thymine (CCAAT)/enhancer-binding proteins ${\alpha}$ and ${\beta}$ (C/EBP${\alpha}$ and C/EBP${\beta}$) and sterol regulatory element binding protein (SREBP), which are adipocyte specific markers. In flow cytometry analysis, the inhibitory effect of differentiation was caused by G1 arrest and following mitotic clonal expansion cease. Therefore, we also investigated the alteration of G1 phase arrest-related proteins. As a result, the expression of p21 protein was significantly increased, while the expressions of Cdk2, E2F-1 and phospho-Rb were reduced in a dose-dependent manner in STME treated 3T3-L1 cells. According to these results, STME might inhibit differentiation through G1 arrest in 3T3-L1 preadipocytes adipogenesis, and further studies, which are in progress, have to be completed to identify the active compounds.