• Journal of Nutrition and Health
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• 제54권4호
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• pp.335-341
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• 2021

Purpose: Muscle mitochondria play a key role in regulating fatty acid and glucose metabolism. Dysfunction of muscle mitochondria is associated with metabolic diseases such as obesity and type 2 diabetes. Isorhamnetin (ISOR), also known as 3-O-methylquercetin, a quercetin metabolite, is a naturally occurring flavonoid in many plants. This study evaluated the effects of ISOR on the regulation of the mitochondrial function of C2C12 muscle cells. Methods: C2C12 muscle cells were differentiated for 5 days, and then treated in various concentrations of ISOR. Cytotoxicity was determined by assessing cell viability using the water-soluble tetrazolium salt-8 assay principle at different concentrations of ISOR and time points. Levels of the mitochondrial DNA (mtDNA) content and gene expression were measured by quantitative real-time polymerase chain reaction. The citrate synthase (CS) activity was quantified by the enzymatic method. Results: ISOR at a concentration of 10 µM did not show any cytotoxic effects. ISOR increased the mtDNA copy number in a time- or dose-dependent manner. The messenger RNA levels of genes involved in mitochondrial function, such as peroxisome proliferator-activated receptor-γ coactivator-1α, and uncoupling protein 3 were significantly stimulated by the ISOR treatment. The CS activity was also significantly increased in a time- or dose-dependent manner. Conclusion: These results suggest that ISOR enhances the regulation of mitochondrial function, which was at least partially mediated via the stimulation of the mtDNA replication, mitochondrial gene expression, and CS activity in C2C12 muscle cells. Therefore, ISOR may be useful as a potential food ingredient to prevent metabolic diseases-associated muscle mitochondrial dysfunction.

• 한국식품과학회지
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• 제49권2호
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• pp.192-202
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• 2017

황정 주정 추출물 ID1216의 고지방 식이 유도 비만 마우스에서의 체중 증가 억제 효과에 대한 분자생물학적 기전을 확인하고자 단백질과 mRNA 수준에서 지질 및 에너지 대사 관련 유전자들의 발현 변화를 관찰하였다. 본 연구에서 확인된 지표들 간의 상호 작용 및 ID1216의 조절 여부에 관해 Fig. 10에 나타내었다. 실험 결과 ID1216은 고지방 식이 유도 비만 마우스에서 체중 증가 억제를 나타내었으며, 비만 대사 관련 pathway의 상위 유전자로 사료되는 SIRT1과 AMPK의 발현을 조절하는 것으로 나타났다. 활성화된 SIRT1과 AMPK는 $PGC1{\alpha}$의 활성화에 관여하고, 이를 통해 열 발산 대사와 관련된 UCP 단백질과 핵 수용체 단백질인 $PPAR{\alpha}$의 발현이 백색지방, 갈색지방, 간 및 근육에서 증가되는 것이 확인되었다. 각 조직 별로 RT-PCR을 진행한 결과에서는 $PPAR{\alpha}$의 하위 유전자인 aP2, ACO, Acadl, Acadm, CPT1a, CPT1b의 mRNA 발현 수준을 향상시켜 주어 ID1216이 지방산 산화 대사인 ${\beta}$-oxidation의 활성화에 기여할 가능성을 보여주었다. 이와는 별개로 ID1216은 중성지질을 분해하는 것으로 알려진 ATGL의 mRNA 발현 또한 증가시키는 것으로 확인되었다. 본 연구를 통해 ID1216이 조직에 따라 지질 및 에너지 대사와 관련된 인자의 발현에 영향을 주는 체중 조절에 효과적인 소재임을 알 수 있었다. 또한 비만 치료제와의 기전적 차별성과 생약 특유의 섭취 안전성을 특징으로 하는 체중 또는 체지방 조절 기능성 소재로의 활용 가능성도 충분히 가지고 있음을 확인할 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제14권4호
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• pp.796-804
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• 2004

We found previously that dietary high fat caused obesity, and levan supplementation to the regular diet reduced adiposity and serum lipids. In the present study, we examined the effects of levan [high-molecular-mass $\beta$-(2,6)-linked fructose polymer] supplement on the development of obesity and lipid metabolism in rats fed with high-fat diet. Thus, to determine whether the dietary levan may have the anti-obesity and hypolipidemic effects, 4-wk-old Sprague Dawley male rats were fed with high-fat diet for 6 wk to induce obesity, and subsequently fed with 0, 1, 5, or 10% levan supplemented high-fat diets (w/w) for another 4 wk. For the comparison, a normal control group was fed with AIN-76A diet. Supplementation with levan resulted in a significant reduction of high-fat-induced body weight gain, white fat (i.e., epididymal, visceral, and peritoneal fat) development, adipocyte hypertrophy, and the development of hyperinsulinemia and hyperlipidemia in a dose-dependent manner. Serum triglyceride and free fatty acid levels were greatly reduced by levan supplementation. Serum total cholesterol level was reduced, whereas the HDL cholesterol level was increased by dietary levan. The expression of uncoupling protein (UCP) was increased by dietary high fat, and was further induced by levan supplementation. The mRNA level of UCP1, 2, and 3 in brown adipose tissue (BAT) and UCP3 in skeletal muscle was upregulated in rats fed with dietary levan. In conclusion, upregulated UCP mRNA expression may contribute to suppression of development of obesity through increased energy expenditure. The present results suggest that levan supplementation to the diet is beneficial in suppressing diet-induced obesity and hyperlipidemia.

• 한국식품영양과학회지
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• 제42권1호
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• pp.1-7
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• 2013

본 연구에서는 3T3-L1 전지방세포를 이용하여 발효 삼정환의 지방 분화 억제 효과를 확인하고자 하였다. 삼정환을 5가지 주요 유산균으로 각각 발효시킨 후, Oil Red O 염색법으로 지방세포 분화 억제 여부를 알아보고, 이의 기전을 알기 위해서 지방생성에 핵심적인 역할을 하는 transcription factor 및 지질 조절 효소의 유전자 발현량을 비교하여 보았다. Oil Red O 염색 분석에서는 Lactobacillus plantarum, Enterococcus faecium으로 발효한 삼정환에서 지방구 수의 감소를 확인할 수 있었다. 또한 transcription factor로 $C/EPB{\alpha}$, $PPAR{\gamma}$, UCP-2 및 콜레스테롤 조절과 관련된 효소인 HMG-CoA reductase의 4가지 유전자 발현 정도를 분석하였는데, 발효시키지 않은 삼정환의 경우 농도가 $100{\mu}L/mL$ 이상일 때 네 가지 항목에서 억제 효과를 나타냈으며, 발효시켰을 때는 유산균의 종류에 따라 효과 억제효과가 있었는데, Lactobacillus plantarum으로 발효한 삼정환이 효과가 가장 좋은 것으로 나타났다. Lactobacillus plantarum으로 발효한 삼정환은 동일 농도의 발효하지 않은 삼정환과 비교했을 때, Oil Red O 실험에서 염색된 지방구 수가 더욱 감소하였으며, $PPAR{\gamma}$, UCP-2, HMG-CoA reductase의 경우 농도가 $200{\mu}L/mL$일 때 각각 35%, 57%, 54%로 5가지 발효 삼정환 중 가장 높은 억제율을 나타내었다. 이에 지방분화 억제 효과를 가진 삼정환을 발효시키면 그 효과가 더욱 증가하는 것으로 나타났는데, 특히 Lactobacillus plantarum으로 발효한 삼정환은 $PPAR{\gamma}$, UCP-2, HMG-CoA reductase의 유전자 발현조절을 통해 지방 분화를 억제시키는 것으로 밝혀져 발효 삼정환은 항비만 혹은 항고지혈증 약물로 개발 가능성이 있는 것으로 사료된다.

• Asian-Australasian Journal of Animal Sciences
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• 제18권11호
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• pp.1552-1556
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• 2005

The UCPs are members of the mitochondrial inner membrane transporter family, present in the mitochondrial inner membrane. Their main function is increasing the energy expenditure via diminishing the resulting production of ATP from mitochondrial oxidative phosphorylation instead of yielding dissipative heat. They are associated with the metabolism of fat and regulation of energy expenditure. The UCP gene can be viewed as the candidate gene for chicken fatness. In the present study, RT-PCR and Northern Blot methods were developed to investigate the expression of the UCP gene in ten tissues including heart, liver, spleen, lung, kidney, gizzard, intestine, brain, breast muscle and abdominal fat of chicken. The results of both RT-PCR and Northern Blot methods showed that the UCP gene expressed specific in breast muscle. The expression levels of UCP gene in breast muscles from egg-type and meat-type chickens of hatching, 2, 4, 6 and 8 wk of age were detected by RT-PCR assay and results showed that the expression levels of UCP gene were related to breeds. Expression level of UCP gene in layers was higher than that in broilers at various weeks of age except at 6 wk. The UCP gene's expression was higher at 6 wk and had no significant difference among other weeks of age in broilers; in layers the expression level of UCP gene had no significant difference among weeks of age. The experiment results also showed that insulin could increase the expression level of UCP gene by 40% compared with control group.

• Journal of Microbiology and Biotechnology
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• 제15권4호
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• pp.823-830
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• 2005

This study was undertaken to evaluate the effect of bacteria-derived $\beta$-glucan fiber on serum lipids, adiposity and uncoupling protein (UCP) expression in rats. In order to induce obesity, Sprague-Dawley weanling male rats were allowed free access to AIN-76A diet until 4 weeks of age, and fed high-fat diet (beef tallow, $40\%$ of calories as fat) for 6 weeks until 10 weeks of age. Rats were then fed with $0\%$ thigh- fat control group), $1\%$, or $5\%$ bacterial ~-glucan supplemented high-fat diets (w/w) for another 6 weeks. For comparison, normal control group was fed with AIN-76 diet $11.7\%$ fat). Supplementation with bacterial $\beta$-glucan resulted in a significant reduction of high-fat-induced white fat (i.e., visceral and peritoneal fat) development, adipocyte hypertrophy, and development of hyperinsulinemia and hyperleptinemia. Serum triglyceride, total cholesterol, and free fatty acid levels were greatly reduced, but, HDL-cholesterol concentrations were increased by bacterial $\beta$-glucan supplementation. Serum leptin level was lower in the $\beta$-glucan groups than in the high-fat group. The expression of UCPs (UCP1, UCP2, and UCP3) in brown adipose tissue (BAT) were significantly increased by $5\%$ bacterial $\beta$-glucan-containing diet. This study suggests that the anti-obesity effect of $5\%$ bacterial $\beta$-glucan is attributed to upregulation of UCPs and inefficient energy utilization.

• Journal of Nutrition and Health
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• 제34권8호
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• pp.865-871
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• 2001

The adipose tissue hormone leptin has been proposed to be involved in the regulation of flood intake and energy expenditure via thermogenesis by uncoupling protein(UCP) in brown adipose tissue(BAT). The objective of the study was to examine the effects of high fat diet on the serum leptin levels, BAT UCPl expression and the body fat mass in rats after weaning. During experimental period of 12 weeks, 4 male Sprague-Dawley rats were killed for the baseline experiment at 4 weeks of age while the remaining rats were fed the two different diets: the control diet AIN-76A(n = 20), high fat(beef tallow) diet(n = 20) ad libitum, which provided 11.7% or 40% of calories as fat, respectively. At 16 weeks of age, the increase in the food efficiency ratio(FER) was related to fat mass in rats on high fat diet. Serum leptin level was increased by age and dietary high fat. There was no difference in serum insulin level between groups until 10 weeks of age, but rats fed high fat diet for 12 weeks showed hyperinsulinemia. The amount of body fat pads was increased significantly in high fat group compared to normal diet group. Visceral fat mass affected acutely by high fat diet, as a result, it was higher in rats fed high fat diet for 2 weeks than normal diet. At 16 weeks of age, BAT and visceral fat mass were significantly high in high fat group. Also, the serum leptin levels reflected the amount of body fat mass. BAT UCPI mRNA expression increased with age and dietary high fat. This study demonstrates that dietary high fat increased serum leptin levels, BAT UCPI expression and body fat mass. Futhermore, in rats fed high fat diets, the increases in leptin and UCPI expression counteracts only in part the excess adiposity and obesity.

• Nutrition Research and Practice
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• 제13권1호
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• pp.3-10
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• 2019

BACKGROUND/OBJECTIVES: The $NAD^+$ precursor nicotinamide riboside (NR) is a type of vitamin $B_3$ found in cow's milk and yeast-containing food products such as beer. Recent studies suggested that NR prevents hearing loss, high-fat diet-induced obesity, Alzheimer's disease, and mitochondrial myopathy. The objective of this study was to investigate the effects of NR on inflammation and mitochondrial biogenesis in AML12 mouse hepatocytes. MATERIALS/METHODS: A subset of hepatocytes was treated with palmitic acid (PA; $250{\mu}M$) for 48 h to induce hepatocyte steatosis. The hepatocytes were treated with NR ($10{\mu}M$ and 10 mM) for 24 h with and without PA. The cell viability and the levels of sirtuins, inflammatory markers, and mitochondrial markers were analyzed. RESULTS: Cytotoxicity of NR was examined by PrestoBlue assay. Exposure to NR had no effect on cell viability or morphology. Gene expression of sirtuin 1 (Sirt1) and Sirt3 was significantly upregulated by NR in PA-treated hepatocytes. However, Sirt1 activities were increased in hepatocytes treated with low-dose NR. Hepatic pro-inflammatory markers including tumor necrosis factor-alpha and interleukin-6 were decreased in NR-treated cells. NR upregulated anti-inflammatory molecule adiponectin, and, tended to down-regulate hepatokine fetuin-A in PA-treated hepatocytes, suggesting its inverse regulation on these cytokines. NR increased levels of mitochondrial markers including peroxisome proliferator-activated receptor ${\gamma}$ coactivator-$1{\alpha}$, carnitine palmitoyltransferase 1, uncoupling protein 2, transcription factor A, mitochondrial and mitochondrial DNA in PA-treated hepatocytes. CONCLUSIONS: These data demonstrated that NR attenuated hepatic inflammation and increased levels of mitochondrial markers in hepatocytes.

• Journal of Nutrition and Health
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• 제55권4호
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• pp.462-475
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• 2022

본 연구는 팔미트산으로 인슐린 저항성을 유도한 C2C12 근육세포주에서 ADLE의 인슐린 저항성개선효과를조사하고이에대한조절기전을확인하고자하였다. C2C12 근육세포주에 ADLE를 처리 시, AMPK의 활성화를 통해 포도당흡수 (glucose uptake)가 증가되었으며, 이는 미토콘드리아-매개 에너지 생합성 조절단백질인 PGC1α, UCP3, CS 활성을 증가시킴과 동시에 지방산 합성인자인 ACC, FAS, SREBP-1의 발현을 억제함을 알 수 있었다. 세포주에서 확인된 결과들을 고지방식이 유도 당뇨마우스의 근육조직에서 조사한 결과, 고지방식이와 ADLE를 동시에 처리한 그룹에서 AMPK 활성화, GLUT4 발현증가와 미토콘드리아 에너지 대사증가, 지방산 합성 감소효과를 보였다. 이상의 결과들로, ADLE가 근육 내 에너지 대사 관련 경로의 상위유전자인 AMPK를 활성화하여 GLUT4의 세포막 이동을 증진시켜 당대사 조절에 관여하는 것을 관찰하였으며, AMPK의 인산화 증가는 PGC1α의 활성화에 관여하고, 이를 통해 열 발산 대사와 관련된 UCP3의 증가 및 CS 활성을 증가시키고, 지방산 합성 관련 유전자 발현을 억제시킴을 알 수 있었다. 본 결과로부터 ADLE는 대사증후군에서 공통적으로 나타나는 인슐린 저항성을 개선시킬 수 있으며, 이는 근육세포에서의 AMPK의 활성화를 통한 에너지생성기전과 관련이 있음을 알 수 있었다. ADLE는 비만, 당뇨 등의 다양한 부작용을 가진 약제와는 다른 안전성을 보장할 수 있는 이점을 가지고 있어 인슐린 저항성 및 제2형 당뇨병 치료를 위한 기능성 식품 소재로의 활용 가능성도 충분히 가지고 있음을 확인할 수 있었다.

• Journal of Nutrition and Health
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• 제57권2호
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• pp.171-184
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• 2024

Purpose: Although activating thermogenic adipocytes is a promising strategy to reduce the risk of obesity and related metabolic disorders, emerging evidence suggests that it is difficult to induce adipocyte thermogenesis in obesity. Therefore, this study aimed to investigate the regulation of adipocyte thermogenesis in diet-induced obesity. Methods: Adipose progenitor cells were isolated from the white and brown adipose tissues of control diet (CD) or high-fat diet (HFD) fed mice, and fully differentiated white and brown adipocytes were treated with β-agonists or 18-carbon fatty acids for β-adrenergic activation or peroxisome proliferator-activated receptor (PPAR) activation. Results: Compared to the CD-fed mice, the expression of uncoupling protein 1 (Ucp1) was lower in the white adipose tissue of the HFD-fed mice; however, this was not observed in the brown adipose tissue. The expression of peroxisome proliferator-activated receptor gamma (Pparg) was lower in the brown adipose progenitor cells isolated from HFD-fed mice than in those isolated from the CD-fed mice. Norepinephrine (NE) treatment exerted lesser effect on peroxisome proliferator-activated receptor-γ coactivator (Pgc1a) upregulation in white adipocytes derived from HFD-fed mice than those derived from CD-fed mice. Regardless which 18-carbon fatty acids were treated, the expression levels of thermogenic genes including Ucp1, Pgc1a, and positive regulatory domain zinc finger region protein 16 (Prdm16) were higher in the white adipocytes derived from HFD-fed mice. Oleic acid (OLA) and γ-linolenic acid (GLA) upregulated Pgc1a expression in white adipocytes derived from HFD-fed mice. Brown adipocytes derived from HFD-fed mice had higher expression levels of Pgc1a and Prdm16 compared to their counterparts. Conclusion: These results indicate that diet-induced obesity may downregulate brown adipogenesis and NE-induced thermogenesis in white adipocytes. Also, HFD feeding may induce thermogenic gene expression in white and brown primary adipocytes, and OLA and GLA could augment the expression levels.