• 한국미생물·생명공학회지
• /
• 제44권1호
• /
• pp.89-97
• /
• 2016

비만은 체내 지방이 과도하게 축적되어 일어나는 현상으로, 당뇨, 고혈압, 심혈관 질환 및 암과 같은 질병의 원인이 된다. 본 연구는 RLE에 의해 지방전구세포에서 지방세포로 분화 시, 세포 내 축적되는 Triglyceride 저해 및 발현되는 전사인자들의 발현양상에 미치는 영향에 대하여 조사하였다. 그 결과, RLE는 Oil Red O 염색에서 세포 내 triglyceride의 축적을 농도 의존적으로 억제하였다. 또한 CCAAT/enhancer binding protein(C/EBP) ${\alpha}$, ${\beta}$와 peroxisome proliferator activated receptor ${\gamma}$($PPAR{\gamma}$)과 같은 지방세포 분화 관련 전사인자들의 발현을 억제하였다. RLE는 clonal expansion 단계의 지방세포를 G1기에서 세포 주기를 정지시켜 세포의 증식을 억제하였으며, RLE 처리에 의해 p21의 증가, Cyclin E, Cdk2, Phospho-Rb의 발현 저해 등 G1 arrest 관련 단백질의 발현 변화가 유도되었다. 따라서, RLE는 분화 관련 전사인자들의 발현을 조절하고 지방세포 분화 초기에 G1기의 세포 주기 정지를 억제함으로써 지방전구세포에서 지방세포로의 분화를 억제한다고 사료된다.

• Natural Product Sciences
• /
• 제17권4호
• /
• pp.273-278
• /
• 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.

• Asian-Australasian Journal of Animal Sciences
• /
• 제30권1호
• /
• pp.111-118
• /
• 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.

• The Korean Journal of Physiology and Pharmacology
• /
• 제20권6호
• /
• pp.649-655
• /
• 2016

TonEBP belongs to the Rel family of transcription factors and plays important roles in inflammation as well as kidney homeostasis. Recent studies suggest that TonEBP expression is also involved in differentiation of several cell types such as myocytes, chondrocytes, and osteocytes. In this study, we investigated the roles of TonEBP during adipocyte differentiation in 3T3-L1 cells. TonEBP mRNA and protein expression was dramatically reduced during adipocyte differentiation. Sustained expression of TonEBP using an adenovirus suppressed the formation of lipid droplets as well as the expression of FABP4, a marker of differentiated adipocytes. TonEBP also inhibited the expression of $PPAR{\gamma}$, a known master regulator of adipocytes. RNAi-mediated knock down of TonEBP promoted adipocyte differentiation. However, overexpression of TonEBP did not affect adipogenesis after the initiation of differentiation. Furthermore, TonEBP expression suppressed mitotic clonal expansion and insulin signaling, which are required early for adipocyte differentiation of 3T3-L1 cells. These results suggest that TonEBP may be an important regulatory factor in the early phase of adipocyte differentiation.

• Nutrition Research and Practice
• /
• 제15권5호
• /
• pp.555-567
• /
• 2021

BACKGROUND/OBJECTIVES: Abeliophyllum distichum is a plant endemic to Korea, containing several beneficial natural compounds. This study investigated the effect of A. distichum leaf extract (ALE) on adipocyte differentiation. MATERIALS/METHODS: The cytotoxic effect of ALE was analyzed using cell viability assay. 3T3-L1 preadipocytes were differentiated using induction media in the presence or absence of ALE. Lipid accumulation was confirmed using Oil Red O staining. The mRNA expression of adipogenic markers was measured using RT-PCR, and the protein expressions of mitogen-activated protein kinase (MAPK) and peroxisome proliferator-activated receptor gamma (PPAR𝛾) were measured using western blot. Cell proliferation was measured by calculating the incorporation of Bromodeoxyuridine (BrdU) into DNA. RESULTS: ALE reduced lipid accumulation in differentiated adipocytes, as indicated by Oil Red O staining and triglyceride assays. Treatment with ALE decreased the gene expression of adipogenic markers such as Ppar𝛾, CCAAT/enhancer binding protein alpha (C/ebp𝛼), lipoprotein lipase, adipocyte protein-2, acetyl-CoA carboxylase, and fatty acid synthase. Also, the protein expression of PPAR𝛄 was reduced by ALE. Treating the cells with ALE at different time points revealed that the inhibitory effect of ALE on adipogenesis is higher in the early period treatment than in the terminal period. Furthermore, ALE inhibited adipocyte differentiation by reducing the early phase of adipogenesis and mitotic clonal expansion. This was indicated by the lower number of cells in the Synthesis phase of the cell cycle (labeled using BrdU assay) and a decrease in the expression of early adipogenic transcription factors such as C/ebp𝛽 and C/ebp𝛿. ALE suppressed the phosphorylation of MAPK, confirming that the effect of ALE was through the suppression of early phase of adipogenesis. CONCLUSIONS: Altogether, the results of the present study revealed that ALE inhibits lipid accumulation and may be a potential agent for managing obesity.

• Nutrition Research and Practice
• /
• 제15권5호
• /
• pp.568-578
• /
• 2021

BACKGROUND/OBJECTIVES: Psidium guajava L. (guava) leaves have been shown to exhibit hypoglycemic and antidiabetic effects in rodents. This study investigated the effects of guava leaf extract on adipogenesis, glucose uptake, and lipolysis of adipocytes to examine whether the antidiabetic properties are mediated through direct effects on adipocytes. MATERIALS/METHODS: 3T3-L1 cells were treated with 25, 50, 100 ㎍/mL of methanol extract from guava leaf extract (GLE) or 0.1% dimethyl sulfoxide as a control. Lipid accumulation was evaluated with Oil Red O Staining and AdipoRed assay. Immunoblotting was performed to measure the expression of adipogenic transcription factors, fatty acid synthase (FAS), and AMP-activated protein kinase (AMPK). Glucose uptake under basal or insulin-stimulated condition was measured using a glucose analog 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxy-D-glucose. Lipolysis from fully differentiated adipocytes was measured by free fatty acids release into the culture medium in the presence or absence of epinephrine. RESULTS: Oil Red O staining and AdipoRed assay have shown that GLE treatment reduced lipid accumulation during adipocyte differentiation. Mitotic clonal expansion, an early essential event for adipocyte differentiation, was inhibited by GLE treatment. GLE inhibited the expression of transcription factors involved in adipocyte differentiation, such as peroxisome proliferator-activated receptor 𝛄 (PPAR𝛄), CCAAT/enhancer-binding protein α (C/EBPα), and sterol regulatory element-binding protein-1c (SREBP-1c). FAS expression was also decreased while the phosphorylation of AMPK was increased by GLE treatment. In addition, GLE increased insulin-induced glucose uptake into adipocytes. In lipid-filled mature adipocytes, GLE enhanced epinephrine-induced lipolysis but reduced basal lipolysis dose-dependently. CONCLUSIONS: The results show that GLE inhibits adipogenesis and improves adipocyte function by reducing basal lipolysis and increasing insulin-stimulated glucose uptake in adipocytes, which can be partly associated with antidiabetic effects of guava leaves.

• Molecules and Cells
• /
• 제45권12호
• /
• pp.963-975
• /
• 2022

Exogenous polyamines are able to induce life span and improve glucose homeostasis and insulin sensitivity. However, the effects of exogenous polyamines on adipocyte differentiation and which polyamine transporters mediate them have not been elucidated yet. Here, we identified for the first time that exogenous polyamines can clearly stimulate adipocyte differentiation through polyamine transporters, solute carrier family 3 member A2 (SLC3A2) and SLC7A1. Exogenous polyamines markedly promote 3T3-L1 adipocyte differentiation by increasing the intracellular lipid accumulation and the expression of both adipogenic and lipogenic genes in a concentration-dependent manner. In particular, exogenous putrescine mainly regulates adipocyte differentiation in the early and intermediate stages. Moreover, we have assessed the expression of polyamine transporter genes in 3T3-L1 preadipocytes and adipocytes. Interestingly, the putrescine-induced adipocyte differentiation was found to be significantly suppressed in response to a treatment with a polyamine transporter inhibitor (AMXT-1501). Furthermore, knockdown experiments using siRNA that specifically targeted SLC3A2 or SLC7A2, revealed that both SLC3A2 and SLC7A2 act as important transporters in the cellular importing of exogenous putrescine. Thus, the exogenous putrescine entering the adipocytes via cellular transporters is involved in adipogenesis through a modulation of both the mitotic clonal expansion and the expression of master transcription factors. Taken together, these results suggest that exogenous polyamines (such as putrescine) entering the adipocytes through polyamine transporters, can stimulate adipogenesis.

• Journal of Nutrition and Health
• /
• 제47권1호
• /
• pp.1-11
• /
• 2014

널리 음용되고 있는 녹차의 EGCG과 우리나라 국민의 상당수가 복용하고 있는 건강기능성 식품 성분인 글루코사민은 이전의 연구들을 통해서 지방세포의 분화를 억제하는데 효과가 있다고 보고되어왔다. 이 두 물질의 병합처리로 기대되어지는 지방세포에서의 adipogenesis 및 지방축적감소에 대한 상승효과는 검증된 바 없으며, 효과에 대한 cell cycle 차원에서의 접근은 없었다. 본 연구 결과에서 EGCG와 Glucosamine 6-phosphate는 adipogenesis 전사인자인 $PPAR{\gamma}$, $C/EBP{\alpha}$, SREBP1에 대한 직접적인 발현 억제 뿐아니라, $PPAR{\gamma}$, $C/EBP{\alpha}$, SREBP1와 매개된 FAS, ACSL1, LPL과 같은 adipogenic target 유전자의 발현 감소를 통하여 지방세포의 분화와 지방세포 내 지방축적을 감소시키는 효과를 나타냈다. 그리고 HSL과 perilipin의 발현조절을 통해 부분적인 lipolytic effet도 나타냈다. 또한 지방세포의 분화가 개시되는데 있어 중요한 DNA의 remodeling 과정인 mitotic clonal expansion (MCE) 과정 중 G0/G1 phase 단계에서 cell cycle 정지 유도와 그로인한 S phase 및 G2/M phase로 세포주기이행의 방해를 통해 지방세포가 분화되는 것은 억제하였다. 이러한 효과들은 EGCG 농도가 높아질수록, 그리고 EGCG를 단독으로 처리한경우보다 Glucosamine 6-phosphate와 병합하였을 때 효과적이었다. 따라서 EGCG 단독처리 및 glucosamine 6-phosphate와의 병합처리는 지방세포에서 adipogenesis와 adipogenic관련 유전자들의 발현 억제 및 MCE 단계의 cell cycle arrest를 통해 지방세포의 분화를 억제하고 지방축적을 감소시켜 항비만 효과를 나타냈으며, 이러한 효과는 두 성분의 병합처리에서 조금 더 효과적이었다고 할 수 있다. 비록 두 성분의 병합처리가 기대했던 만큼은 아니었으나 항비만 효과에 대한 상승효과가 있다고 볼 수 있다.