Lipid Accumulation In 3T3-L1 Cells Research Articles

Glycoproteins isolated from scallop shells inhibit differentiation of 3T3-L1 preadipocyte cells

We previously demonstrated that the organic components isolated from scallop shells (scallop shell extract) inhibit the differentiation of 3T3-L1 preadipocyte cells. In this study, we show that a pronase-treated scallop shell extract inhibited differentiation, but degradation of sugar chains in the scallop shell extract with trifluoromethane sulfonic acid resulted in the loss of the differentiation-inhibiting activity, suggesting that the sugar chain modifications were responsible for the inhibitory activity. To identify the bioactive substance in the scallop shell extract, we isolated glycoproteins from the scallop shell extract via affinity chromatography using concanavalin A (Con A), wheat germ agglutinin, lens culinaris agglutinin (LCA), and ricinus communis agglutinin. LCA and Con A binding fractions inhibited the differentiation of 3T3-L1 preadipocyte cells. In addition, a glycoprotein with a molecular weight of 16 kDa that was purified from the LCA binding fraction reduced lipid accumulation in 3T3-L1 cells during differentiation. The glycoprotein inhibited differentiation-associated mitotic clonal expansion and suppressed the expression of an adipocyte-specific protein, fatty acid binding protein. These results suggest that the sugar chains of glycoproteins in the scallop shell extract inhibit the differentiation of 3T3-L1 preadipocyte cells.

Coptis chinensis alkaloids exert anti-adipogenic activity on 3T3-L1 adipocytes by downregulating C/EBP-α and PPAR-γ

Obesity is a complex, multifactorial, and chronic disease that increases the risk for type 2 diabetes, coronary heart disease and hypertension, and has become a major worldwide health problem. Developing novel anti-obesity drugs from natural products is a promising solution to the global health problem of obesity. While screening anti-obesity potentials of natural products, the methanol extract of the rhizome of Coptis chinensis (Coptidis Rhizoma) was found to significantly inhibit adipocyte differentiation and lipid contents in 3T3-L1 cells, as assessed by Oil-Red O staining. Five known alkaloids, berberine, epiberberine, coptisine, palmatine, and magnoflorine, were isolated from the n-BuOH fraction of the methanol extract of Coptidis Rhizoma. We determined the chemical structure of these alkaloids through comparisons of published nuclear magnetic resonance (NMR) spectral data. Furthermore, we screened these alkaloids for their ability to inhibit adipogenesis over a range of concentrations (12.5–50μM). All five Coptidis Rhizoma alkaloids significantly inhibited lipid accumulation in 3T3-L1 cells without affecting cell viability in a concentration dependent manner. In addition, the five alkaloids significantly reduced the expression levels of several adipocyte marker genes including proliferator activated receptor-γ (PPAR-γ) and CCAAT/enhancer-binding protein-α (C/EBP-α). In the present study, we found that the isolated alkaloids inhibited adipogenesis in a dose-dependent manner in 3T3-L1 cells; this inhibition was attributed to their abilities to downregulate the protein levels of the adipocyte marker proteins PPAR-γ and C/EBP-α. Thus, these results suggest that Coptidis Rhizoma extract and its isolated alkaloids may be of therapeutic interest with respect to the treatment of obesity.

Adenovirus type 9 enhances differentiation and decreases cytokine release from preadipocytes.

The hypothesis was that preadipocytes would have intrinsically elevated propensity to differentiate into mature adipocytes due to AdV9 infection. To test this hypothesis, the metabolic and molecular mechanisms responsible for AdV9-induced adipogenesis were examined. An association between anti-AdV9 antibodies and human obesity was also identified. 3T3L1 cells were used as a surrogate model to analyze the preadipocyte proliferation, differentiation, and maturation. An expression of E4orf1, C/EBP-β, PPAR-γ, GAPDH, aP2, LEP and fatty acid synthase gene, intracellular lipid accumulation and cytokine release were assessed. The presence of anti-AdV antibodies, serum lipids, plasma leptin, and CRP was evaluated in 204 obese and non-obese patients. AdV9-infected cells accumulated more intracellular lipids in comparison to uninfected controls. AdV9 enhanced an expression of C/EBP-β and PPAR-γ leading to an increased differentiation of preadipocytes. Overexpression of aP2 and fatty acid synthase, and decreased expression of leptin confirmed an increased accumulation of intracellular lipids due to AdV infection. Secretion of TNF-α and IL-6 from AdV9-inoculated cells was decreased strongly. About 24.5% of prevalence of anti-AdV9 antibodies was reported in the study group. AdV9-infected subjects presented higher body weights, BMIs, WHR, and central obesity. The presence of anti-AdV9 antibodies was associated with changes in serum lipids level but neither elevated CRP nor decreased leptin levels were related to obesity due to AdV infection. Data obtained from this study provide the evidences that AdV9 is a second adenovirus, which has an influence on differentiation and lipid accumulation of 3T3L1 cells.

Eleutheroside E, an active compound from Eleutherococcus senticosus, regulates adipogenesis in 3T3-L1 cells

In this study, we investigated the anti-adipogenic effects of Eleutherococcus senticosus and its active compounds in vitro to examine new functions. We first analyzed the active compounds in E. senticosus growing in Korea using HPLC and found that the concentration of eleutheroside B and E was higher in stems and roots than in other plant parts. There were no significant (p<0.05) differences in eleutheroside concentration between plant ages. Anti-adipogenic effects of E. senticosus on lipid accumulation in 3T3-L1 cells were examined. Extracts of stems and roots more effectively inhibited lipid accumulation in 3T3-L1 cells than extracts of other plant parts. Eleutheroside E was responsible for the pharmacological anti-adipogenic effects via regulation of the mTOR pathway. This is the first report of an anti-adipogenic effect of E. senticosus and the active compound eleutheroside E.

The chalcones cardamonin and flavokawain B inhibit the differentiation of preadipocytes to adipocytes by activating ERK

AimWe searched for polyphenols capable of inhibiting the lipid accumulation in 3T3-L1 cells, and investigated the mechanisms of two effective chalcones cardamonin and flavokawain B on differentiation of preadipocytes. Method and resultsWe treated 3T3-L1 cells with a panel of 46 polyphenols and measured intracellular lipid accumulation by Sudan II staining. Four of them, including cardamonin and flavokawain B, inhibited lipid accumulation. In the further study, cardamonin and flavokawain B inhibited lipid accumulation by downregulating the expression of CCAAT/enhancer binding protein (C/EBP)-β, C/EBPα, and peroxisome proliferator-activated receptor-γ (PPARγ) at both mRNA and protein levels. Cardamonin and flavokawain B also increased phosphorylation of extracellular signal-regulated kinase (ERK) in the early phase of adipocyte differentiation. PD98059, an ERK inhibitor, restored C/EBPβ, PPARγ expression and intracellular lipid accumulation in adipocytes. Moreover, cardamonin and flavokawain B also modulated the secretion of C-reactive protein, dipeptidyl peptidase IV, interleukin-6, tumor necrosis factor-α and fibroblast growth factor-21 in mature adipocytes. ConclusionsThese results indicate that ERK activation and consequent downregulation of adipocyte-specific transcription factors are involved in the inhibitory effects of the chalcones cardamonin and flavokawain B on adipocyte differentiation. Moreover, cardamonin and flavokawain B are able to modulate secretion of adipokines in mature adipocytes.

Allium senescens L. Inhibits Reactive Oxygen Species (ROS) Production and Lipid Accumulation During Differentiation in 3T3‐L1 cells (LB408)

Allium vegetables are rich in flavonols and organosulfur compounds, which have anti‐inflammatory, anti‐oxidant, anti‐cancer, prevention of cardiovascular system and tumor inhibitory properties. In Allium vegetables, however, only a few studies have been reported whether the effect on lipid accumulation is involved in the regulation of reactive oxygen species (ROS) production. Thus, Allium senescens L., one of the Allium vegetables, was used to show the effects of ROS production and lipid accumulation during adipogenesis in 3T3‐L1 cells. Our results indicated that DPPH (1,1‐diphenyl‐2‐picryl hydrazyl) radical scavenging activity of Allium senescens L. increased in a dose depnedent manner. The effects of Allium senescens L. on ROS production and lipid accumulation in 3T3‐L1 cells were evaluated by examining ROS‐regulating genes and adipogenic trascription factors at the molecular level. Allium senescens L. inhibited ROS production 21.47% at 100 μg/mL and decreased intracellular lipid accumulation by 46.17% at 100μg/mL during adipogenesis. Allium senescens L. inhibited the mRNA expression of pro‐oxidant enzymes, such as glucose‐6‐phosphate dehydrogenase (G6PDH) and leads to a reduction in the mRNA levels of the transcription factors, sterol regulatory element binding proteins 1c (SREBP1c), peroxisome proliferator‐activated receptor (PPAR) γ, and CCAAT/enhancer‐binding proteins (C/EBP) α. This strudy showed that Allium senescens L. inhibited ROS production and lipid accumulation by controlling ROS regulating genes and adipogenic trascription factors in adipocytes. It represented that anti‐adipogenic properties of Allium senescensL. by inhibition of adipogenic gene expression mediated by ROS suppression through ROS‐related gene regulation. Thus, Allium senescens L. has potent natural antioxidant with anti‐adipogenic properties and provides useful data in the development of a potent anti‐obesity agent.Grant Funding Source: This work was supported by Priority Research Centers Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education, Science and Technology(KNF‐2009‐0094017).

어린 으름잎 추출물(Akebia quinata D. Leaves)의 항비만 효과

본 연구에서 어린 으름잎으로부터 추출된 열수추출물인 AQH와 80% 주정추출물인 AQE를 대상으로 3T3-L1 전지방세포의 지방세포 분화과정 중에 처리한 후, Oil Red O 염색법에 의한 lipid accumulation, intracellular 중성지방 함량을 평가하고 free glycerol release 함량을 측정하여 지방세포형성 억제능을 확인하며, ICR 마우스를 대상으로 고지방식이 섭취 하에 어린 으름잎 추출물의 경구투여에 따른 체중과 백색지방에 작용하는 효과를 평가하여 어린 으름잎 추출물의 항비만 효과를 밝히고자 하였다. 3T3-L1 지방세포 분화과정 중 AQH 및 AQE 추출물을 처리한 결과 AQE 처리군에서만 유의적 감소를 나타내었다. Intracellular 중성지방 함량의 경우도 AQE 처리군에서 유의적으로 감소되었다. 지방세포 분화 중 배양액으로 유출되는 free glycerol 함량을 평가한 결과에서도 AQE 처리군의 유의적 감소를 확인할 수 있었다. 이상의 결과를 통해 AQE는 3T3-L1 지방세포 분화과정 중에 지방구 생성 억제 및 지방세포의 지방세포 생성 억제효과가 있는 것으로 판명되었다. 마우스에서 8주간 고지방식이 하에 600 mg/kg/day의 AQE를 경구투여하였을 때 고지방식이군과 비교하여 체중 및 체중증가량이 통계적으로 유의하게 감소하였고, 부정소 주위 및 신장 주위 백색지방의 감소가 나타났다. AQE 투여에 의한 체중 감소 및 부정소 주위 백색지방량의 감소는 양성대조군으로 사용한 Orlistat의 경구투여 결과와 유사하였다. 이상의 결과로 세포수준에서의 지방세포 분화 억제, 지방구 생성 억제 작용과 실험동물에서 체중증가량 및 체지방의 감소 작용을 갖는 AQE는 향후 항비만 효과를 갖는 소재로 유용하게 사용될 수 있을 것으로 사료된다.

2′,4′-Dihydroxy-6′-methoxy-3′,5′-dimethylchalcone Promoted Glucose Uptake and Imposed a Paradoxical Effect on Adipocyte Differentiation in 3T3-L1 Cells

2',4'-Dihydroxy-6'-methoxy-3',5'-dimethylchalcone (DMC), one of the flavonoids isolated and purified from the dried flower buds of Cleistocalyx operculatus, was explored for its function in glucose uptake/glycogen synthesis in insulin-sensitive tissue cells and its effect and mechanism on 3T3-L1 preadipocyte differentiation. DMC (10 μM) treatment remarkably promoted glucose uptake in differentiated 3T3-L1 adipocytes (P < 0.05 vs control group), whereas the glucose uptake in L6 myoblasts and glycogen synthesis in HepG2 hepatocytes were not affected by the treatment. DMC had paradoxical effects on lipid accumulation in 3T3-L1 cells compared with differentiation control. High concentrations of DMC (10 and 20 μM) markedly diminished lipid accumulation; however, a low concentration of DMC (2.5 μM) enhanced lipid storage in 3T3-L1 cells (P < 0.01 vs differentiation control group), and 5 μM DMC did not impose a significant effect. It was demonstrated that the effect of DMC in lipid accumulation was controlled by the expression of PPAR-γ.

Inhibitory Effects of Brazilian Propolis on Lipid Accumulation in 3T3-L1 Cells

We here investigated the inhibitory effect of Brazilian propolis on intracellular lipid accumulation. Seven ethanolic extracts of Brazilian propolis were tested for their inhibitory effect on intracellular lipid accumulation in 3T3-L1 cells. Among the seven Brazilian propolis, the extracts AF-08 and AF-18 had inhibitory effects on intracellular lipid accumulation. In particular, the Brazilian propolis AF-08 exhibited a potential inhibitory effect on intracellular lipid accumulation.Thus, these results suggest that the Brazilian propolis AF-08 contributes to the prevention of metabolic syndrome. In addition, five known triterpenoids were isolated from the Brazilian propolis AF-08: betulonic acid, moronic acid, 3-oxo oleanolic acid, masticadienonic acid, and anwnweizonic acid. Four of the triterpenoids exhibited an inhibitory effect on intracellular lipid accumulation. Thus, these triterpenoids may be important as antiobesity agents that inhibit the metabolic syndrome.

추출용매에 따른 울금 추출물의 라디칼 소거능 및 항비만 효과

ABSTRACT In the present study, the levels of phenolic compounds and flavonoids, as well as activities of radical scavenging (DPPH and ABTS radical scavenging activity) and anti-obesity were assessed with cold water (CLC), hot water (CLH), and methanolic (CLM) extracts of Curcuma longa L. (turmeric). Our results showed that the phenolic compounds of CLC, CLH and CLM were 3.68±0.80%, 3.94±0.74% and 9.01±0.73%, respectively. The DPPH and ABTS radical scavenging activities of the CLM were significantly higher than that of the water extracts (CLC and CLH). During the adipocyte differentiation, the treatment of CLM more significantly inhibited lipid accumulation in 3T3-L1 cells than that of the water extracts. These results indicate that the stimulation of radical scavenging potential and the inhibition of adipogenesis were brought on by the lipophilic compounds of turmeric. Key words: turmeric, radical scavenging, 3T3-L1, adipogenesis, anti-obesity Received 26 November 2013; Accepted 3 December 2013

Trigonelline attenuates the adipocyte differentiation and lipid accumulation in 3T3-L1 cells

Trigonelline is a natural alkaloid mainly found in Trigonella Foenum Graecum (fenugreek) Fabaceae and other edible plants with a variety of medicinal applications. Therefore, we investigated the molecular mechanism of trigonelline (TG) on the inhibition of adipocyte differentiation and lipid accumulation in 3T3-L1 cells. Trigonelline suppressed lipid droplet accumulation in a concentration (75 and 100μM) dependent manner. Treatment of adipocyte with of TG down regulates the peroxisome proliferator-activated receptor (PPARγ) and CCAAT element binding protein (C/EBP-α) mRNA expression, which leads to further down regulation of other gene such as adiponectin, adipogenin, leptin, resistin and adipocyte fatty acid binding protein (aP2) as compared with respective control cells on 5th and 10th day of differentiation. Further, addition of triognelline along with troglitazone to the adipocyte attenuated the troglitazone effects on PPARγ mediated differentiation and lipid accumulation in 3T3-L1 cells. Trigonelline might compete against troglitazone for its binding to the PPARγ. In addition, adipocyte treated with trigonelline and isoproterenol separately. Isoproterenol, a lipolytic agent which inhibits the fatty acid synthase and GLUT-4 transporter expression via cAMP mediated pathway, we found that similar magnitude response of fatty acid synthase and GLUT-4 transporter expression in trigonelline treated adipocyte. These results suggest that the trigonelline inhibits the adipogenesis by its influences on the expression PPARγ, which leads to subsequent down regulation of PPAR-γ mediated pathway during adipogenesis. Our findings provide key approach to the mechanism underlying the anti-adipogenic activity of trigonelline.

Phlorotannins isolated from the edible brown alga Ecklonia stolonifera exert anti-adipogenic activity on 3T3-L1 adipocytes by downregulating C/EBPα and PPARγ

The dramatic increase in obesity-related diseases emphasizes the need to elucidate the cellular and molecular mechanisms underlying fat metabolism. Inhibition of adipocyte differentiation has been suggested to be an important strategy for preventing or treating obesity. In our previous study, we characterized an Ecklonia stolonifera extract and non-polar fractions thereof, including dichloromethane and ethyl acetate fractions. We showed that these fractions inhibited adipocyte differentiation and lipid formation/accumulation in 3T3-L1 preadipocytes, as assessed by Oil Red O staining. As part of our ongoing search for anti-obesity agents derived from E. stolonifera, in this work, we characterized five known phlorotannins, including phloroglucinol, eckol, dieckol, dioxinodehydroeckol, and phlorofucofuroeckol A, all of which were isolated from the active ethyl acetate fraction of E. stolonifera. We determined the chemical structures of these phlorotannins through comparisons of published nuclear magnetic resonance (NMR) spectral data. Furthermore, we screened these phlorotannins for their abilities to inhibit adipogenesis over a range of concentrations (12.5–100μM). Of these five phlorotannins, phloroglucinol, eckol, and phlorofucofuroeckol A significantly concentration-dependently inhibited lipid accumulation in 3T3-L1 cells without affecting cell viability. In addition, the five isolated phlorotannins also significantly reduced the expression levels of several adipocyte marker genes, including proliferator activated receptor γ (PPARγ) and CCAAT/enhancer-binding protein α (C/EBPα), although they did so to different extents. These results suggest that the molecular weight of a phlorotannin is an important factor affecting its ability to inhibit adipocyte differentiation and modulate the expression levels of adipocyte marker genes.

Nicotinamide, a glucose-6-phosphate dehydrogenase non-competitive mixed inhibitor, modifies redox balance and lipid accumulation in 3T3-L1 cells

AimsExcessive energy uptake of dietary carbohydrates results in their storage as fat and requires glucose-6-phosphate dehydrogenase (G6PD)-mediated NADPH production. We sought to assess whether the nicotinamide-induced reduction of G6PD activity might modulate redox balance and lipid accumulation in 3T3-L1 cells. Main methods3T3-L1 preadipocytes (days 4 and 6 of differentiation) and adipocytes were cultured in the presence of 5 or 25mM glucose. The cells cultured in 25mM glucose were supplemented with nicotinamide (5–15mM). Next, we evaluated the following parameters: cell viability, apoptosis, lipid accumulation, lipolysis, reducing power, reactive oxygen species (ROS), NAD(P)H and NAD(P)+, isocitrate dehydrogenase (IDP), malic enzyme and G6PD, as well as the protein and mRNA levels of G6PD. We also analysed the kinetics of the nicotinamide-induced inhibition of G6PD. Key findingsG6PD mRNA levels increased at day 4 of adipocyte differentiation, whereas G6PD activity progressively increased at days 4 and 6 of differentiation and was reduced in adipocytes. Concomitantly, ROS, reducing power and lipid accumulation increased gradually as the preadipocytes matured into adipocytes. High glucose increased the activity of G6PD, which coincided with an increase in ROS, reducing power and lipid accumulation. All of these changes are prevented by nicotinamide, with the exception of lipid accumulation in adipocytes. Nicotinamide increased IDP activity without affecting NADPH levels. Lastly, nicotinamide inhibited G6PD in a non-competitive mixed way. SignificanceNicotinamide modulates G6PD via a non-competitive mixed inhibition and decreases high glucose-dependent oxidative stress and lipid accumulation. Nicotinamide maintains NADPH levels by increasing the activity of IDP.

Inhibitory Effects of Ethyl Acetate-Soluble Fraction from Morus alba on Lipid Accumulation in 3T3-L1 Cells

Fruits of mulberry (Morus alba) have been widely used for therapeutic purposes in Asian countries for centuries. Treatment of 3T3-L1 cells with ethanolic extracts of M. alba decreased adipocyte differentiation at 100 microg/mL by 18.6%. Treatment suppressed mRNA levels of PPARgamma and C/EBPalpha expression in 3T3-L1 cells. However, the extract did not change free glycerol release from mature adipocytes. Thus, M. alba inhibited lipid accumulation by regulating transcription factors in 3T3-L1 adipocytes without a lipolytic effect. Among the soluble- fractions, the ethyl acetate-soluble fraction had the highest antiadipogenic effects on 3T3-L1 cells. This fraction decreasing intracellular lipid accumulation by 38.5% in response to treatment with 100 microg/mL. In addition, HPLC analysis of the ethyl acetate-soluble fraction of M. alba contained 167.7 microM of protocatechulic acid in 1 mg/mL of fraction, which inhibited lipid accumulation by 44.8% in response to treatment with 100 microM. From these results, M. alba is a possible candidate for regulating lipid accumulation in obesity.

Shikonin suppresses ERK 1/2 phosphorylation during the early stages of adipocyte differentiation in 3T3-L1 cells

BackgroundThe naphthoquinone pigment, shikonin, is a major component of Lithospermum erythrorhizon and has been shown to have various biological functions, including antimicrobial, anti-inflammatory, and antitumor effects. In this study, we investigated the effect of shikonin on adipocyte differentiation and its mechanism of action in 3T3-L1 cells.MethodsTo investigate the effects of shikonin on adipocyte differentiation, 3T3-L1 cells were induced to differentiate using 3-isobutyl-1-methylzanthine, dexamethasone, and insulin (MDI) for 8 days in the presence of 0–2 μM shikonin. Oil Red O staining was performed to determine the lipid accumulation in 3T3-L1 cells. To elucidate the anti-adipogenic mechanism of shikonin, adipogenic transcription factors, the phosphorylation levels of ERK, and adipogenic gene expression were analyzed by Western blotting and quantitative real-time PCR. To further confirm that shikonin inhibits adipogenic differentiation through downregulation of ERK 1/2 activity, 3T3-L1 cells were treated with shikonin in the presence of FGF-2, an activator, or PD98059, an inhibitor, of the ERK1/2 signaling pathway.ResultsShikonin effectively suppressed adipogenesis and downregulated the protein levels of 2 major transcription factors, PPARγ and C/EBPα, as well as the adipocyte specific gene aP2 in a dose-dependent manner. qRT-PCR analysis revealed that shikonin inhibited mRNA expression of adipogenesis-related genes, such as PPARγ, C/EBPα, and aP2. Adipocyte differentiation was mediated by ERK 1/2 phosphorylation, which was confirmed by pretreatment with PD98059 (an ERK 1/2 inhibitor) or FGF-2 (an ERK 1/2 activator). The phosphorylation of ERK1/2 during the early stages of adipogenesis in 3T3-L1 cells was inhibited by shikonin. We also confirmed that FGF-2-stimulated ERK 1/2 activity was attenuated by shikonin.ConclusionsThese results demonstrate that shikonin inhibits adipogenic differentiation via suppression of the ERK signaling pathway during the early stages of adipogenesis.

Zinc-chelated Vitamin C Stimulates Adipogenesis of 3T3-L1 Cells.

Adipose tissue development and function play a critical role in the regulation of energy balance, lipid metabolism, and the pathophysiology of metabolic syndromes. Although the effect of zinc ascorbate supplementation in diabetes or glycemic control is known in humans, the underlying mechanism is not well described. Here, we investigated the effect of a zinc-chelated vitamin C (ZnC) compound on the adipogenic differentiation of 3T3-L1 preadipocytes. Treatment with ZnC for 8 d significantly promoted adipogenesis, which was characterized by increased glycerol-3-phosphate dehydrogenase activity and intracellular lipid accumulation in 3T3-L1 cells. Meanwhile, ZnC induced a pronounced up-regulation of the expression of glucose transporter type 4 (GLUT4) and the adipocyte-specific gene adipocyte protein 2 (aP2). Analysis of mRNA and protein levels further showed that ZnC increased the sequential expression of peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer-binding protein alpha (C/EBPα), the key transcription factors of adipogenesis. These results indicate that ZnC could promote adipogenesis through PPARγ and C/EBPα, which act synergistically for the expression of aP2 and GLUT4, leading to the generation of insulin-responsive adipocytes and can thereby be useful as a novel therapeutic agent for the management of diabetes and related metabolic disorders.

GPER mediates the inhibitory actions of estrogen on adipogenesis in 3T3-L1 cells through perturbation of mitotic clonal expansion

G-protein-coupled estrogen receptor 1 (GPER) mediates non-genomic signaling of estrogenic events. Here we showed for the first time that Gper/GPER is expressed in Swiss 3T3 mouse embryo preadipocytes 3T3-L1, and that Gper/GPER is up-regulated during differentiation of the cells induced by monocyte differentiation-inducing (MDI) cocktail. Activation of GPER by the natural ligand 17β-estradiol (E2), and the specific agonist G1, was shown to inhibit lipid accumulation in 3T3-L1 cells, while such inhibition was reversed upon knockdown of GPER using specific siRNA. GPER was also found to mediate perturbation of mitotic clonal expansion (MCE) in these cells by inhibiting cell cycle arrest during MDI cocktail-induced differentiation. Persistent activation of cell cycle regulating factors cyclin-dependant kinase (CDK) 4, CDK6 and cyclin D1, and phosphorylation of retinoblastoma (Rb) protein at serine 795 was observed in the G1-treated cells. Taken together, our results indicate that E2-GPER signaling leads to an inhibition of adipogenesis in 3T3-L1 cells via perturbation of MCE.

Antiobesity Effect ofCodonopsis lanceolatain High-Calorie/High-Fat-Diet-Induced Obese Rats

The antiobesity effects of Codonopsis lanceolata (CL) were evaluated in a high-calorie/high-fat-diet (HFD-) induced obesity rat model and 3T3-L1 cells. The Sprague-Dawley male rats were fed a normal diet (ND) or a HFD for a period of 12 weeks. The rats were subdivided into groups: ND, ND + wild Codonopsis lanceolata (wCL) (900 mg/kg/day, p.o.), ND + cultivated Codonopsis lanceolata (cCL) (900 mg/kg/day, p.o.), HFD, HFD + wCL (100, 300, or 900 mg/kg/day, p.o.), HFD + cCL (100, 300, or 900 mg/kg/day, p.o.), and HFD + sibutramine. The body weight gains of the administered HFD + CL (wCL or CCL) were lower than those of the rats fed with only the HFD group. Moreover, the weight of adipose pads and the serum levels of triglycerides, total cholesterol, and low density lipoprotein cholesterol in the group administered HDL + CL were significantly lower than in the HFD group. The inhibitory effect of lipid accumulation in 3T3-L1 cells was measured by Oil Red O staining and reverse transcription-polymerase chain reaction (RT-PCR). Treatment of 3T3-L1 cells with wCL inhibited lipid accumulation and expression of C/EBPα and PPARγ. These results suggest that CL has a great potential as a functional food with anti-obesity effects and as a therapeutic alternative in the treatment of obesity.

Potent effects of, and mechanisms for, modification of crosstalk between macrophages and adipocytes by lactobacilli

The murine macrophage-like cell line J774.1 was treated with heat-killed cells of Lactobacillus GG (LGG) and L. gasseri TMC0356 (TMC 0356). Interleukin (IL)-6, IL-12, and tumor necrosis factor-α were profiled from the J774.1 cells using enzyme-linked immunosorbent assay methods. The conditioned medium from cultured J774.1 cells was transferred to the preadipocyte cell line 3T3-L1 (which is a mouse embryonic fibroblast-adipose-like cell line). Growth and differentiation of 3T3-L1 cells were monitored by analyzing lipid accumulation and expression of peroxisome proliferator-activated receptor (PPAR)-γ mRNA. The medium conditioned by 3T3-L1 cells was added to J774.1 cells and the cytokines in the supernatant analyzed. Compared with that of cells exposed to a PBS-conditioned medium, lipid accumulation in 3T3-L1 cells was significantly suppressed in a dose-dependent manner by each medium that had been conditioned with LGG and TMC0356. PPAR-γ mRNA expression in 3T3-L1 cells was also significantly downregulated (P < 0.01, P < 0.05, respectively). The conditioned medium of 3T3-L1 adipose phenotype significantly stimulated production of IL-6 and IL-12 in J774.1 cells treated with LGG and TMC0356. These results suggest that lactobacilli may suppress differentiation of preadipocytes through macrophage activation and alter the immune responses of macrophages to adipose cells.

Centipede grass exerts anti-adipogenic activity through inhibition of C/EBPβ, C/EBPα, and PPARγ expression and the AKT signaling pathway in 3T3-L1 adipocytes

BackgroundCentipede grass (CG) originates from China and South America and is reported to contain several C-glycosyl flavones and phenolic constituents, including maysin and luteolin derivatives. This study aimed to investigate, for the first time, the antiobesity activity of CG and its potential molecular mechanism in 3T3-L1 cells.MethodsTo study the effect of CG on adipogenesis, differentiating 3T3-L1 cells were treated every day with CG at various concentrations (0–100 μg/ml) for six days. Oil-red O staining and triglyceride content assay were performed to determine the lipid accumulation in 3T3-L1 cells. The expression of mRNAs or proteins associated with adipogenesis was measured using RT-PCR and Western blotting analysis. We examined the effect of CG on level of phosphorylated Akt in 3T3-L1 cells treated with CG at various concentration s during adipocyte differentiation.ResultsDifferentiation was investigated with an Oil-red O staining assay using CG-treated 3T3-L1 adipocytes. We found that CG suppressed lipid droplet formation and adipocyte differentiation in 3T3-L1 cells in a dose-dependent manner. Treatment of the 3T3-L1 adipocytes with CG resulted in an attenuation of the expression of adipogenesis-related factors and lipid metabolic genes. The expression of C/EBPα and PPARγ, the central transcriptional regulators of adipogenesis, was decreased by the treatment with CG. The expression of genes involved in lipid metabolism, aP2 were significantly inhibited following the CG treatment. Moreover, the CG treatment down-regulated the phosphorylation levels of Akt and GSK3β.ConclusionsTaken collectively, these data indicated that CG exerts antiadipogenic activity by inhibiting the expression of C/EBPβ, C/EBPα, and PPARγ and the Akt signaling pathway in 3T3-L1 adipocytes.