• 대한한방내과학회지
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• 제34권1호
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• pp.14-30
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• 2013

Objectives : The aim of this study was to investigate whether the effects of extract from Saengkankunbi-tang and its composition that Artimisiae capillaris Herba, Crataegi Fructus, Alismatis Rhizoma, Hoelen and Raphani Semen could protect HepG2 cells from palmitic acid-induced lipotoxicity through lysosomal and mitochondrial pathways in an in vitro model. Methods : To examine the effects of the extracts from Saengkankunbi-tang and its composition that Artimisiae capillaris Herba, Crataegi Fructus, Alismatis Rhizoma, Hoelen and Raphani Semen on palmitic acid-induced lipotoxicity in HepG2 cells, we measured the contents of cell viability, cytotoxicity. Then to investigate the effects of the extract from Saengkankunbi-tang, Artimisiae capillaris Herba and Raphani Semen, we measured that triglyceride, reactive oxygen species, ATP levels, glutathione levels, cytochrome c and cathepsin B. Results : The extracts from Saengkankunbi-tang and its composition had a cell-protective function. The extracts from Saengkankunbi-tang, Artimisiae capillaris Herba and Raphani Semen controlled triglyceride over-accumulation in cells and reduced overproduction of reactive oxygen species. The extracts from Saengkankunbi-tang and Raphani Semen increased ATP and glutathione levels which had been decreased by lipotoxicity. The extracts from Saengkankunbi-tang, Artimisiae capillaris Herba and Raphani Semen reduced leakage of cytochrome c and the extracts from Saengkankunbi-tang and Raphani Semen reduced leakage of cathepsin B in lipotoxicity. Conclusions : These results show that the extracts from Saengkankunbi-tang and its composition that Artimisiae capillaris Herba and Raphani Semen have cell protective effects on palmitic acid-induced lipotoxicity through lysosomal and mitochondrial pathways.

• Toxicological Research
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• 제24권2호
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• pp.129-135
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• 2008

The results of recent studies indicate that high levels of free fatty acids(FFAs) and adipokines may be the main causes of non-alcoholic liver disease; however, the molecular mechanism that links FFAs to lipotoxicity remains unclear. In the present study, we treated HepG2 cells with FFA(either palmitate or oleate) to investigate the mechanisms involved in lipotoxicity in the liver cells. We also treated cells with palmitate in the presence of a chemical chaperone, 4-phenylbutyric acid(PBA), to confirm the involvement of ER stress in lipotoxicity. Palmitate significantly induced cytotoxicity in dose- and time-dependent manners. Apoptosis was also significantly induced by palmitate as measured by caspase-3 activity and DAPI staining. Palmitate led to increased expressions of the spliced form of X-box-protein(Xbp)-1 mRNA and C/EBP homologous transcription factor(CHOP) protein, suggesting activation of the unfolded-protein response. PBA co-incubation significantly attenuated apoptosis induced by palmitate. The above data demonstrate that high levels of palmitate induce apoptosis via the mediation of ER stress in the liver cells and that chemical chaperones act to modulate ER stress and accompanying apoptosis.

• Toxicological Research
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• 제27권2호
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• pp.103-110
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• 2011

Lipotoxicity involves pathological alterations to cells and tissues in response to elevated fat levels in blood. Furthermore, this process can disturb both cellular homeostasis and viability. In the current study, the authors show that neural progenitor cells (NPCs) are vulnerable to high levels of palmitic acid (PA) a saturated fatty acid. PA was found to cause cell death associated with elevated reactive oxygen species (ROS) levels, and to reduce NPCs proliferation. To evaluate the lipotoxicity of PA in adult NPCs in the hippocampus, male C57BL/6 mice were divided into two groups and maintained on either a normal diet (ND) or PA-rich high fat diet (HFD) for 2 weeks. Interestingly, short-term PA-rich HFD feeding reduced the survival of newly generated cells in the hippocampal dentate gyrus and hippocampal brain-derived neurotrophic factor levels. These findings suggest PA has a potent lipotoxicity in NPCs and that a PA-rich HFD disrupts hippocampal neurogenesis.

• Journal of Ginseng Research
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• 제47권4호
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• pp.572-582
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• 2023

Background: Free fatty acid-induced lipotoxicity is considered to play an important role in pancreatic β-cell dysfunction. The effect of ginsenosides on palmitic acid-induced pancreatic beta-cells cell death and failure of glucose-stimulated secretion of insulin (GSIS) was evaluated in this study. Methods: Enzyme-linked immunosorbent assay kit for a rat insulin was used to quantify glucose-stimulated insulin secretion. Protein expression was examined by western blotting analysis. Nuclear condensation was measured by staining with Hoechst 33342 stain. Apoptotic cell death was assessed by staining with Annexin V. Oil Red O staining was used to measure lipid accumulation. Results: We screened ginsenosides to prevent palmitic acid-induced cell death and impairment of GSIS in INS-1 pancreatic β-cells and identified protopanaxadiol (PPD) as a potential therapeutic agent. The protection effect of PPD was likely due to a reduction in apoptosis and lipid accumulation. PPD attenuated the palmitic acid-induced increase in the levels of B-cell lymphoma-2-associated X/B-cell lymphoma 2, poly (ADP-ribose) polymerase and cleaved caspase-3. Moreover, PPD prevented palmitic acid-induced impairment of insulin secretion, which was accompanied by an increase in the activation of phosphatidylinositol 3-kinase, peroxisome proliferator-activated receptor γ, insulin receptor substrate-2, serine-threonine kinase, and pancreatic and duodenal homeobox-1. Conclusion: Our results suggest that the protective effect of PPD on lipotoxicity and lipid accumulation induced by palmitic acid in pancreatic β-cells.

• The Korean Journal of Physiology and Pharmacology
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• 제27권3호
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• pp.221-230
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• 2023

Diabetic kidney disease is one of the most serious complications of diabetes. Although diabetic kidney disease can be effectively controlled through strict blood glucose management and corresponding symptomatic treatment, these therapies cannot reduce its incidence in diabetic patients. The sodium-glucose cotransporter 2 (SGLT2) inhibitors and the traditional Chinese herb "Gegen" have been widely used in diabetes-related therapy. However, it remains unclear whether the combined use of these two kinds of medicines contributes to an increased curative effect on diabetic kidney disease. In this study, we examined this issue by evaluating the efficacy of the combination of puerarin, an active ingredient of Gegen, and canagliflozin, an SGLT2 inhibitor for a 12-week intervention using a mouse model of diabetes. The results indicated that the combination of puerarin and canagliflozin was superior to canagliflozin alone in improving the metabolic and renal function parameters of diabetic mice. Our findings suggested that the renoprotective effect of combined puerarin and canagliflozin in diabetic mice was achieved by reducing renal lipid accumulation. This study provides a new strategy for the clinical prevention and treatment of diabetic kidney disease. The puerarin and SGLT2 inhibitor combination therapy at the initial stage of diabetes may effectively delay the occurrence of diabetic kidney injury, and significantly alleviate the burden of renal lipotoxicity.

• 생명과학회지
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• 제23권12호
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• pp.1509-1515
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• 2013

'지질독성'이라는 용어는 근육과 같은 지방세포가 아닌 조직에서 여분의 지질 축적이 어떻게 세포의 기능저하와 괴사를 유도하는지를 설명하는데 사용되어 왔다. 고지방을 투여한 근세포 배양에서 지질독성이 확인된 바는 있지만, 생체 내 시험에서, 특히 지질독성에 의해 대사적으로 영향을 받는 Type-I 근육에서 이러한 결과가 확인된 바는 없다. 이 연구의 목적은 고지방식이가 쥐의 Type-I 근육의 형태학적 변화와 세포사멸 단백질 발현에 어떠한 영향을 미치는지를 밝히는 것이다. 이를 위해 6주간 고지방식이와 일반식이를 섭취한 쥐의 Type-I 근육 내 지질축적, 염증반응, 핵 침윤현상, cleaved PARP 단백질 발현을 각각 Oil Red O staining, H & E staining, Western blot 을 이용하여 비교 분석하였다. 6주 후 고지방식이 집단에서 지질축적, 염증반응, 핵 침윤현상, cleaved PARP 단백질 발현이 일반식이 집단에서 유의하게 증가하였다. Type-I 근육량은 일반식이 집단에 비해서 고지방식이 집단에서 낮은 경향을 보였으나 통계적으로 유의하지는 않았다. 이러한 결과는 고지방 식이가 지질독성에 의해 Type-I 근육의 세포괴사를 유도한다는 것을 의미하며, 이는 고지방 섭취가 직접적으로 근 감소증과 관련이 있음을 시사한다.

• 한국축산식품학회지
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• 제33권3호
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• pp.411-416
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• 2013

본 연구는 가르시니아 캄보지아의 항비만 효과의 분자기전을 알아보기 위하여 지방전구세포인 3T3-L1세포의 지방세포로의 분화 시, 가르시니아 캄보지아 추출물을 처리하여 세포 내 지질 적의 형성 및 중성지방의 축적, 지방 분화 특이 지표 단백질의 발현에 미치는 영향에 대하여 살펴보았다. 3T3-L1세포의 지방 세포로의 분화는 MDI로 유도 후, 2일째부터 지방 적 및 중성 지방이 유의하게 축적되기 시작하였는데, 1% 가르시니아 캄보지아 추출물을 동시에 처리한 세포에서 이러한 지방 적 및 중성 지방의 축적이 유의하게 억제되는 것을 실험을 통해 확인할 수 있었다. 또한 지방세포 분화 특이 지표 단백질로 알려진 $PPAR{\gamma}2$, $C/EBP{\alpha}$, aP2와 같은 단백질의 발현 또한 가르시니아 캄보지아 추출물이 효과적으로 억제하고 있음도 확인할 수 있었다. 한편, 가르시니아 캄보지아 추출물은 palmitate를 처리한 HepG2 세포에서 중성지방의 축적 및 세포사멸을 유의하게 억제함으로써 유리 지방산의 축적에 의한 지속적인 염증 반응으로 유발되는 지방독성(lipotoxicity)을 억제하는 효과가 있음을 확인할 수 있었다. 이러한 결과들은 가르시니아 캄보지아 추출물이 세포 수준에서 비교적 낮은 농도로도 효과적으로 비만을 억제할 수 있으며, 기존에 알려지지 않았던 유리지방산에 의한 지방독성을 억제하는 효과가 있음을 본 연구에서 확인할 수 있었다.

• 대한한방내과학회지
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• 제30권2호
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• pp.257-269
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• 2009

Objective : Obesity is an important cause of diabetes, and lipotoxicity causes insulin resistance. Recently a lot of research is being done on PPAR-${\alpha}$. TNF-${\alpha}$. adiponectin, and leptin, which are important obesity related factors. In this study, we investigated the effects of Supungsunki-hwan on high fat. high carbohydrate diet-induced obese type 2 diabetic mouse models. Methods: Diabetes was induced in ICR male mouse (30${\pm}$5g) with Surwit's high fat, high sucrose diet. Mice were divided into 4 groups(n=10) of Normal. Control. Supungsunkj-hwan group. and acarbose group. The Supungsunki-hwsn group was given 10% Supungsunkj-hwan in their diet. and the acarbose group was given 0.5% acarbose in their diet. After 6 weeks. body weight. food intake, FBS and OGTT. lipid profile and liver enzymes, epididymal fat weight, and gene expression of leptin, adiponectin, TNF-${\alpha}$ and PPAR-${\alpha}$ were measured. Leptin. adiponectin. tumor necrosis factor(TNF)-${\alpha}$ and peroxisome proliferator-activated receptor (PPAR)-${\alpha}$ were evaluated by reverse transcription-polymerase chain reaction. Results : Supungsunkj-hwan increased the gene expression of PPAR-${\alpha}$, which reduces lipotoxicity and insulin resistance. Supungsunkj-hwan also significantly reduced triglyceride. AST. ALT serum levels. and 1 hour oral glucose tolerance levels. Conclusion : These results show that Supungsunkj-hwan improves insulin resistance in the liver and muscles, by reducing triglyceride levels and lipotoxicity through increased PPAR-${\alpha}$ gene expression. This is supported by the fact that Supungsunkj-hwan significantly reduces 1 hour oral glucose tolerance levels. Therefore we suggest that Supungsunkj-hwan would be an effective treatment for obese type 2 diabetic patients.

• Journal of Yeungnam Medical Science
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• 제34권1호
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• pp.19-28
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• 2017

The incidence of type 2 diabetes mellitus and insulin resistance is growing rapidly. Multiple organs including the liver, skeletal muscle and adipose tissue control insulin sensitivity coordinately, but the mechanism of skeletal muscle insulin resistance has not yet been fully elucidated. However, there is a growing body of evidence that lipotoxicity induced by mitochondrial dysfunction in skeletal muscle is an important mediator of insulin resistance. However, some recent findings suggest that skeletal mitochondrial dysfunction generated by genetic manipulation is not always correlated with insulin resistance in animal models. A high fat diet can provoke insulin resistance despite a coordinate increase in skeletal muscle mitochondria, which implies that mitochondrial dysfunction is not mandatory in insulin resistance. Furthermore, incomplete fatty acid oxidation by excessive nutrition supply compared to mitochondrial demand can induce insulin resistance without preceding impairment of mitochondrial function. Taken together we suggested that skeletal muscle mitochondrial overloading, not mitochondrial dysfunction, plays a pivotal role in insulin resistance.

• Molecules and Cells
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• 제43권1호
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• pp.66-75
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• 2020

Saturated fatty acids contribute to β-cell dysfunction in the onset of type 2 diabetes mellitus. Cellular responses to lipotoxicity include oxidative stress, endoplasmic reticulum (ER) stress, and blockage of autophagy. Palmitate induces ER Ca²⁺ depletion followed by notable store-operated Ca²⁺ entry. Subsequent elevation of cytosolic Ca²⁺ can activate undesirable signaling pathways culminating in cell death. Mitochondrial Ca²⁺ uniporter (MCU) is the major route for Ca²⁺ uptake into the matrix and couples metabolism with insulin secretion. However, it has been unclear whether mitochondrial Ca²⁺ uptake plays a protective role or contributes to lipotoxicity. Here, we observed palmitate upregulated MCU protein expression in a mouse clonal β-cell, MIN6, under normal glucose, but not high glucose medium. Palmitate elevated baseline cytosolic Ca²⁺ concentration ([Ca²⁺]_i) and reduced depolarization-triggered Ca²⁺ influx likely due to the inactivation of voltage-gated Ca²⁺ channels (VGCCs). Targeted reduction of MCU expression using RNA interference abolished mitochondrial superoxide production but exacerbated palmitate-induced [Ca²⁺]_i overload. Consequently, MCU knockdown aggravated blockage of autophagic degradation. In contrast, co-treatment with verapamil, a VGCC inhibitor, prevented palmitate-induced basal [Ca²⁺]_i elevation and defective [Ca²⁺]_i transients. Extracellular Ca²⁺ chelation as well as VGCC inhibitors effectively rescued autophagy defects and cytotoxicity. These observations suggest enhanced mitochondrial Ca²⁺ uptake via MCU upregulation is a mechanism by which pancreatic β-cells are able to alleviate cytosolic Ca²⁺ overload and its detrimental consequences.