• Molecules and Cells
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• v.39 no.11
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• pp.797-806
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• 2016

Lipogenesis is under the concerted action of ChREBP, SREBP-1c and other transcription factors in response to glucose and insulin. The isolated porcine preadipocytes were differentiated into mature adipocytes to investigate the roles and interrelation of these transcription factors in the context of glucose- and insulin-induced lipogenesis in pigs. In ChREBP-silenced adipocytes, glucose-induced lipogenesis decreased by ~70%, however insulin-induced lipogenesis was unaffected. Moreover, insulin had no effect on ChREBP expression of unperturbed adipocytes irrespective of glucose concentration, suggesting ChREBP mediate glucose-induced lipogenesis. Insulin stimulated SREBP-1c expression and when SREBP-1c activation was blocked, and the insulin-induced lipogenesis decreased by ~55%, suggesting SREBP-1c is a key transcription factor mediating insulin-induced lipogenesis. $LXR{\alpha}$ activation promoted lipogenesis and lipogenic genes expression. In ChREBP-silenced or SREBP-1c activation blocked adipocytes, $LXR{\alpha}$ activation facilitated lipogenesis and SREBP-1c expression, but had no effect on ChREBP expression. Therefore, $LXR{\alpha}$ might mediate lipogenesis via SREBP-1c rather than ChREBP. When ChREBP expression was silenced and SREBP-1c activation blocked simultaneously, glucose and insulin were still able to stimulated lipogenesis and lipogenic genes expression, and $LXR{\alpha}$ activation enhanced these effects, suggesting $LXR{\alpha}$ mediated directly glucose- and insulin-induced lipogenesis. In summary, glucose and insulin stimulated lipogenesis through both dissimilar and identical regulation pathway in porcine adipocytes.

• Preventive Nutrition and Food Science
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• v.3 no.4
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• pp.362-367
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• 1998

Thyroid hormone(T3) stimulates hepatic lipogenesis by increasing expression of genes, indluding acetyl-CoA carboxylase and fatty acid synthase. S14 protein, which is thougth to be involved in lipid metabolism , appears to respond in parallel . Effect of T3 on lipogenesis in white and brown adipose tissue are less clear, and may be complicated by indirect effects of the hormone. We developed an adipocytes system where the indirect effects of thyroid hormone are abolished and direct effects of T3 on lipogenesis could be tested. Fat accumulation was mesured by Oil-Red O staining. Insulin clearly enhanced fat accumulation by 2-fold . Isobutylemethylxanthie(IBMX) apeared to inhibit insulin -stimulated fat accumulation. Dexamethasone increased insulin-stimulatedfat accumulation about 1.3-fold. confluent adipocytes were cultured in serum-free medium or medium containing 10% fetal calf serum or 10% fetal calf serum stripped of thyroid hormone and lipogenesis, assessed by the incorporation of 3H2O , was measured. Medium without serum or supplemented with T3-depleted serum did not amplify the stimulatory effect of T3 on lipogenesis compared to medium containing 10% fetal calf seru. Dexamethasone alone led to a decrease inlopogenesis of about 50 % in white adipocytes and 25% in brown adipocytes. However, dexamethasone amplified the lipogenic respnse to T3 by about 30% in whit eadipocytes and 60% in brown adipocytes. T3(1$\mu$M) stimulated lipogenesis and acetyl-CoA carboxylase and fatty acid syntase mRNA levels up to 2 -fold in both types of adipocytes. It seems that these adipocytes systems are as useful model to study the effects of hormones on lipogenic gene expression as well as lipogenesis.

• Journal of Life Science
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• v.32 no.4
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• pp.318-324
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• 2022

PPARγ and C/EBPα are master adipogenic transcription factors (TFs) required for adipose tissue development. They control the induction of many adipocyte genes and the early phase of adipogenesis in the embryonic development of adipose tissue. Adipose tissue continues to expand after birth, which, as a late phase of adipogenesis, requires the lipogenesis of adipocytes. In particular, the liver and adipose tissues are major sites for de novo lipogenesis (DNL), where carbohydrates are primarily converted to fatty acids. Furthermore, fatty acids are esterified with glycerol-3-phosphate to produce triglyceride, a major source of lipid droplets in adipocytes. Hepatic DNL has been actively studied, but the DNL of adipocytes in vivo remains not fully understood. Thus, an understanding of lipogenesis and adipose expansion may provide therapeutic opportunities for obesity, type 2 diabetes, and metabolic diseases. In adipocytes, DNL gene expression is transcriptionally regulated by lipogenesis coactivators, as well as by lipogenic TFs such as ChREBP and SREBP1a. Recent in vivo studies have revealed new insights into the lipogenesis gene expression and adipose expansion. Future detailed molecular mechanism studies will determine how nutrients and metabolism regulate DNL and adipose expansion. This review will summarize recent updates of DNL in adipocytes and adipose expansion in terms of transcriptional regulation.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.9
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• pp.1285-1289
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• 2000

This study investigated the lipogenesis capacity of hepatocytes and lipolysis rate of adipocytes of broilers as affected by different fatty acids (trial one) and different linoleic acid (C18:2) levels (trial two). Twenty 6-wk old broilers were used; their hepatocytes and adipocytes were isolated for the in vitro study. In trial one, four treatments were tested. The control group in which no fatty acid was added, and the test groups to which were added $300{\mu}M$ of C16:0, C18:1 and C18:2, respectively. For trial two, different levels (0, $300{\mu}M$ and 1 mM) of C18:2 combined to fatty acid-free bovine serum albumin (BSA) were added to the medium. According to results of trial one, added fatty acids significantly reduced the incorporation by hepatocytes of [U,$^{14}C$]glucose into total lipid (p<0.05); the lipogenesis capacity in C18:2 group was the lowest. Although a similar pattern was found with [l,$^{14}C$]acetate, the groups only slightly differed in terms of lipogenesis capacity (p=0.11). In addition, the C18:2 group had a significantly (p<0.05) greater lipolysis rate than the C16:0 and control groups. Results of trial two indicated that C18:2 significantly (p<0.05) reduced lipogenesis capacity both for [U,$^{14}C$]glucose and [l,$^{14}C$]acetate, and markedly stimulated the lipolysis rate (p<0.05), displaying a dose response. Results presented herein demonstrate that C18:2 can reduce lipogenesis capacity and stimulate the lipolysis rate in broilers.

• Korean Journal of Acupuncture
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• v.31 no.4
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• pp.168-178
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• 2014

Objectives : Mahuang-Chuanwu(Mahwang-Cheonoh) Pharmacopuncture(MCP) has been used to treat obesity in Clinical Korean Medicine. MCP solution(MCPS) is also expected to have strong anti-obesity activities. However, little is known about the mechanisms of its inhibitory effects on adipocyte differentiation and lipogenesis. Methods : In the present study, we examined the effects of MCPS on differentiation and lipogenesis of 3T3-L1 adipocytes. To elucidate the mechanism of the effects of MCPS on lowering lipid content in 3T3-L1 adipocytes, we examined whether MCPS modulates the expressions of transcription factors to induce lipogenesis and adipogenic genes related to regulate the accumulation of lipids. Results : Our results showed that MCPS significantly inhibited differentiation and lipogenesis of 3T3-L1 adipocytes in a dose-dependent manner. MCPS suppressed the mRNA expressions of cytidine-cytidine-adenosine-adenosine-thymidine(CCAAT)/enhancer binding proteins ${\alpha}$($C/EBP{\alpha}$), C/EBP ${\beta}$, $C/EBP{\delta}$, and peroxisome proliferator-activated receptor ${\gamma}$($PPAR{\gamma}$) genes related to the induction of adipose differentiation. MCPS inhibited the mRNA expressions of adipose-specific aP2, adipsin, lipoprotein lipase(LPL), CD36, TGF-${\beta}$, and leptin genes related to the fat formation. MCPS downregulated the mRNA expressions of liver X receptor(LXR) ${\alpha}$ and fatty acid synthase(FAS) genes related to the induction of lipogenesis. In addition, MCPS reduced the production of adipocyte-induced pro-inflammatory cytokines. Conclusions : MCPS could regulate the accumulation of lipids and expression of adipogenic genes via inhibition of transcript factors related to induction of adipose differentiation.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.9
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• pp.1417-1423
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• 2007

The present study was conducted to investigate the supplementation effects of $C_{18:2}$ rich-soybean oil or $C_{18:3}$ rich-perilla oil (7% of total diet, DM basis) for 12 weeks on plasma metabolites, fatty acid profile, in vitro lipogenesis, and activities of LPL and FAS in adipose tissue of sheep. The treatments were basal diet (Control), $C_{18:2}$ rich-soybean oil supplemented diet (SO-D) and $C_{18:3}$ rich-perilla oil supplemented diet (PO-D). All the sheep were fed the diets consisting of roughage to concentrate in the ratio of 40:60 (DM basis). Oil supplemented diets (SO-D and PO-D) slightly increased contents of triglyceride (TG) and total cholesterol (TC), proportions of both cis-9 trans-11 and trans-10 cis-12 CLA and TVA, but lowered (p<0.01) those of $C_{18:0}$ compared to the control diet. No differences were observed in the contents of TG and TC and proportions of fatty acids in plasma between supplemented oils. Oil supplemented diets slightly increased the proportions of cis-9 trans-11 and trans-10 cis-12 types of CLA in subcutaneous adipose tissue of sheep compared to the control diet. The rate of lipogenesis with acetate was higher (p<0.01) for intermuscular- and subcutaneous adipose tissues than that for intramuscular adipose tissue, while that with glucose did not differ among fat locations in sheep fed SO-D. No differences were observed in the rate of lipogenesis between substrates in all fat locations. The rates of lipogenesis with glucose increased only in the intermuscular- (p<0.01) and subcutaneous adipose tissue (p<0.005) compared to those with acetate. The rates of lipogenesis with acetate were the highest in the intermuscular and intramuscular adipose tissue of the sheep fed PO-D. Oil supplemented diets slightly increased the rate of lipogenesis with glucose for all fat locations. Supplementation of oils to the diet numerically increased the fatty acid synthase activity but did not affect the lipoprotein lipase activity in subcutaneous adipose tissue.

• Molecules and Cells
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• v.44 no.2
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• pp.116-125
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• 2021

Cardiovascular diseases (CVDs) are the most common cause of death in patients with nonalcoholic fatty liver disease (NAFLD) and dyslipidemia is considered at least partially responsible for the increased CVD risk in NAFLD patients. The aim of the present study is to understand how hepatic de novo lipogenesis influences hepatic cholesterol content as well as its effects on the plasma lipid levels. Hepatic lipogenesis was induced in mice by feeding a fat-free/high-sucrose (FF/HS) diet and the metabolic pathways associated with cholesterol were then analyzed. Both liver triglyceride and cholesterol contents were significantly increased in mice fed an FF/HS diet. Activation of fatty acid synthesis driven by the activation of sterol regulatory element binding protein (SREBP)-1c resulted in the increased liver triglycerides. The augmented cholesterol content in the liver could not be explained by an increased cholesterol synthesis, which was decreased by the FF/HS diet. HMG-CoA reductase protein level was decreased in mice fed an FF/HS diet. We found that the liver retained more cholesterol through a reduced excretion of bile acids, a reduced fecal cholesterol excretion, and an increased cholesterol uptake from plasma lipoproteins. Very low-density lipoproteintriglyceride and -cholesterol secretion were increased in mice fed an FF/HS diet, which led to hypertriglyceridemia and hypercholesterolemia in Ldlr-/- mice, a model that exhibits a more human like lipoprotein profile. These findings suggest that dietary cholesterol intake and cholesterol synthesis rates cannot only explain the hypercholesterolemia associated with NAFLD, and that the control of fatty acid synthesis should be considered for the management of dyslipidemia.

• Journal of Animal Science and Technology
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• v.52 no.5
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• pp.383-388
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• 2010

Identification of natural compounds that can prevent the development of obesity in vivo is time consuming and expensive. We have used in vitro systems derived from pig adipose tissue to screen simple aqueous or ethanolic extracts of Korean medicinal herbs (KMH) for their anti-adipogenic potential. A total of 183 extracts were tested for their actions in lipogenesis of pig adipose tissue and differentiation of pig preadipocytes. Ethanol extracts were prepared from 72 and aqueous extracts were prepared from 111 medicinal herbs. Both an ethanolic and an aqueous extract were prepared from 65 of these. Thirteen extracts substantially altered rates of lipogenesis in vitro. The effects of KMH on lipogenesis of pig adipose tissue are as follows. Elevens reduced lipogenesis to rates that were more than 40% lower than control and four of these reduced rates of lipogenesis by more than 70%. The most potent anti-lipogenic extracts were those obtained in ethanol from Iridaceae and from Sophora flavescens AIT as well as both the aqueous and ethanolic extracts from Lysimachia vulgaris L. Two extracts, those prepared in water from Caesalpiniae lignum and from Phellodendri cortex, were found to promote rates of lipogenesis in vitro. The effects of KMH on differentiation of pig preadoipocytes are as follows. Twentyeight extracts altered the rates of differentiation of cultured porcine preadipocytes. Sixteen increased and twelve reduced the rates of differentiation of preadipocytes. Extracts prepared in ethanol from Moutan radicis cortex and from Ostericum koreanum and those prepared in water from Angelicae gigantis radix, from Inula henenium L and from Magnolia flos doubled the rate of differentiation of cultured porcine preadipocytes. Ten extracts reduced the in vitro rate of differentiation of porcine preadipocytes by more than 35%. These were the ethanolic extracts from Glycyrrizae radix, Nepetae spica and from Polygala myrtifolia and the aqueous extracts from Amaranthaceae, Asparagus cochinchinesis, Atractylodis rhizoma alba, Citrus junos TANAKA, Cyperus rotundus, Epimedium grandiflorum and from Moutan radicis cortex. Only the ethanolic extract from Polygala myrtifolia was able to both reduce lipogenesis in adipose tissue slices and retard differentiation of cultured preadipocytes. The results of our study will provide meaningful information to identify medicinal herbs which would reduce fat deposition in livestocks and humans.

• Journal of Microbiology and Biotechnology
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• v.23 no.11
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• pp.1569-1576
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• 2013

In mice, supplementation of t10,c12 conjugated linoleic acid (CLA) increases liver mass and hepatic steatosis via increasing uptake of fatty acids released from adipose tissues. However, the effects of t10,c12 CLA on hepatic lipid synthesis and the associated mechanisms are largely unknown. Thus, we tested the hypothesis that gut microbiota-producing t10,c12 CLA would induce de novo lipogenesis and triglyceride (TG) synthesis in HepG2 cells, promoting lipid accumulation. It was found that treatment with t10,c12 CLA ($100{\mu}M$) for 72 h increased neutral lipid accumulation via enhanced incorporation of acetate, palmitate, oleate, and 2-deoxyglucose into TG. Furthermore, treatment with t10,c12 CLA led to increased mRNA expression and protein levels of lipogenic genes including SREBP1, ACC1, FASN, ELOVL6, GPAT1, and DGAT1, presenting potential mechanisms by which CLA may increase lipid deposition. Most strikingly, t10,c12 CLA treatment for 3 h increased phosphorylation of mTOR, S6K, and S6. Taken together, gut microbiota-producing t10,c12 CLA activates hepatic de novo lipogenesis and TG synthesis through activation of the mTOR/SREBP1 pathway, with consequent lipid accumulation in HepG2 cells.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.4
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• pp.428-433
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• 1998

The effects of chromium picolinate supplementation in pig diet were evaluated by measuring the in vitro lipogenic and lipolytic activities in adipose tissue and the protein synthetic activity in liver acinar cell in culture. Thirty-two male and thirty-two female pigs were randomly assigned to one of four dietary groups: Control, 100 ppb, 200 ppb, and 400 ppb of Cr in the form of picolinate. The chromium picolinate supplementation (p < 0.01) increased the in vitro lipolytic activity in adipose tissue of pig, but had no effects on lipogenesis. The chromium picolinate effect was greater in female pigs than in male pigs on lipolytic activity. The results from the studies with the liver acinar cells in culture indicated that chromium picolinate supplementation increased protein synthetic activity (p < 0.05). It was observed through this experiment that chromium picolinate functions not only on fat degradation but also on retained protein synthesis.