• Molecules and Cells
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• v.40 no.6
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• pp.393-400
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• 2017

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disease characterized by lack of insulin and high glucose levels. T2DM can cause bone loss and fracture, thus leading to diabetic osteoporosis. Promoting osteogenic differentiation of osteoblasts may effectively treat diabetic osteoporosis. We previously reported that Sirtuin 1 (Sirt1), a $NAD^+$-dependent deacetylase, promotes osteogenic differentiation through downregulation of peroxisome proliferator-activated receptor (PPAR) ${\gamma}$. We also found that miR-132 regulates osteogenic differentiation by downregulating Sirt1 in a $PPAR{\beta}/{\delta}$-dependent manner. The ligand-activated transcription factor, $PPAR{\alpha}$, is another isotype of the peroxisome proliferator-activated receptor family that helps maintain bone homeostasis and promot bone formation. Whether the regulatory role of $PPAR{\alpha}$ in osteogenic differentiation is mediated via Sirt1 remains unclear. In the present study, we aimed to determine this role and the underlying mechanism by using high glucose (HG) and free fatty acids (FFA) to mimic T2DM in MC3T3-E1 cells. The results showed that HG-FFA significantly inhibited expression of $PPAR{\alpha}$, Sirt1 and osteogenic differentiation, but these effects were markedly reversed by $PPAR{\alpha}$ overexpression. Moreover, siSirt1 attenuated the positive effects of $PPAR{\alpha}$ on osteogenic differentiation, suggesting that $PPAR{\alpha}$ promotes osteogenic differentiation in a Sirt1-dependent manner. Luciferase activity assay confirmed interactions between $PPAR{\alpha}$ and Sirt1. These findings indicate that $PPAR{\alpha}$ promotes osteogenic differentiation via the Sirt1-dependent signaling pathway.

• Journal of Life Science
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• v.30 no.7
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• pp.640-650
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• 2020

Fibroblast growth factor 21 (FGF21) is an atypical member of the FGF protein family which is highly synthesized in the liver, pancreas, and adipose tissue. Depending on the expression tissue, FGF21 uses endo- or paracrine features to regulate several metabolic pathways including glucose metabolism and energy homeostasis. Different physiologically stressful conditions such as starvation, a ketogenic diet, extreme cold, and mitochondrial dysfunction are known to induce FGF21 synthesis in various tissues to exert either adaptive or defensive mechanisms. More specifically, peroxisome proliferator-activated receptor gamma and peroxisome proliferator-activated receptor alpha control FGF21 expression in adipose tissue and liver, respectively. In addition, the pharmacologic administration of FGF21 has been reported to decrease the body weight and improve the insulin sensitivity and lipoprotein profiles of obese mice and type 2 diabetes patients meaning that FGF21 has attracted huge interest as a therapeutic agent for type 2 diabetes, obesity, and non-alcoholic fatty liver disease. However, understanding FGF21 remains complicated due to the paradoxical condition of its tissue-dependent expression. For example, nutrient deprivation largely increases hepatic FGF21 levels whereas adipose tissue-derived FGF21 is increased under feeding condition. This review discusses the issues of interest that have arisen from existing publications, including the tissue-specific function of FGF21 and its action mechanism. We also summarize the current stage of a clinical trial using several FGF21 analogs.

• Journal of Ginseng Research
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• v.41 no.3
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• pp.240-246
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• 2017

Background: Korean Red Ginseng (KRG) is a traditional herbal medicine made by steaming and drying fresh ginseng. It strengthens the endocrine and immune systems to ameliorate various inflammatory responses. The cyclooxygenase-2 (COX-2)/prostaglandin E2 pathway has important implications for inflammation responses and tumorigenesis. Peroxisome proliferator-activated receptor gamma ($PPAR{\gamma}$) is a transcription factor that regulates not only adipogenesis and lipid homeostasis, but also angiogenesis and inflammatory responses. Methods: The effects of the KRG on inhibition of hypoxia-induced COX-2 via $PPAR{\gamma}$ in A549 cells were determined by luciferase assay, Western blot, and/or quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The antimigration and invasive effects of KRG were evaluated on A549 cells using migration and matrigel invasion assays. Results and conclusion: We previously reported that hypoxia-induced COX-2 protein and mRNA levels were suppressed by KRG. This study examines the possibility of $PPAR{\gamma}$ as a cellular target of KRG for the suppression of hypoxia-induced COX-2. $PPAR{\gamma}$ protein levels and $PPAR{\gamma}$-responsive element (PPRE)-driven reporter activities were increased by KRG. Reduction of hypoxia-induced COX-2 by KRG was abolished by the $PPAR{\gamma}$ inhibitor GW9662. In addition, the inhibition of $PPAR{\gamma}$ abolished the effect of KRG on hypoxia-induced cell migration and invasion. Discussion: Our results show that KRG inhibition of hypoxia-induced COX-2 expression and cell invasion is dependent on $PPAR{\gamma}$ activation, supporting the therapeutic potential for suppression of inflammation under hypoxia. Further studies are required to demonstrate whether KRG activates directly $PPAR{\gamma}$ and to identify the constituents responsible for this activity.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.247.1-247.1
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• 2003

PPAR-$\gamma$(Peroxisome Proliferator-Activated Receptor $\gamma$) 리간드들은 논문 조사를 통해 이루어졌다. PPAR-$\gamma$의 45개 알려진 화합물들을 찾았고, 12 생물활성 화합물을 선택했다. 리간드(rosiglitazone)과 단백질의 결합된 구조는 (1fm6)는 PDB로부터 획득했고, 단백질 coordinate를 가져와 PPAR의 활성 영역 잔기들은 확인했다. (2TYR, 1SER, 1HIS). CoMFA와 Flexi Dock을 통해 단백질과 리간드 사이의 상호작용과 결합에너지에 대한 상호 관계를 밝혔다.

• Journal of Life Science
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• v.24 no.1
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• pp.67-73
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• 2014

This study was conducted to investigate the effects of supplementation with Opuntia humifusa on the expression of peroxisome proliferator-activated receptor-delta (PPAR-${\delta}$), peroxisome proliferator-activated receptor-gamma (PPAR-${\gamma}$) and peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-$1{\alpha}$) in the skeletal muscle of rats fed a high-fat diet. Sixteen Sprague-Dawley male rats at 6 weeks of age were randomly divided into 2 groups: a control diet group (CG, n=8) and an experimental diet group (EG, n=8). The rats were fed a high-fat diet (CG) or a high-fat diet supplemented with 5% O. humifusa (EG) for 8 weeks. The results showed that the abdominal fat pad and epididymal fat pad weights were significantly lower in the EG than in the CG (p<0.01). In the blood, serum glucose, triglycerides, and total cholesterol in the EG group were lower than in the CG (p<0.01). The expression of PPAR-${\gamma}$ and PGC-$1{\alpha}$ protein in the skeletal muscle of the EG was increased compared with that of the CG (p<0.05). These results indicate that 8 weeks of O. humifusa supplementation lowers serum glucose and triglyceride levels and suppresses weight gain by reducing fat weight through an increase in the expression of PPAR-${\gamma}$ and PGC-$1{\alpha}$ in the muscle tissue of rats.

• Biomolecules & Therapeutics
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• v.31 no.3
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• pp.312-318
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• 2023

The natural flavonoid macakurzin C (1) exhibited adiponectin biosynthesis-inducing activity during adipogenesis in human bone marrow mesenchymal stem cells and its molecular mechanism was directly associated with a pan-peroxisome proliferator-activated receptor (PPAR) modulator affecting all three PPAR subtypes α, γ, and δ. In this study, increases in adiponectin biosynthesis-inducing activity by macakurzin C derivatives (2-7) were studied. The most potent adiponectin biosynthesis-inducing compound 6, macakurzin C 3,5-dimethylether, was elucidated as a dual PPARα/γ modulator. Compound 6 may exhibit the most potent activity because of the antagonistic relationship between PPARδ and PPARγ. Docking studies revealed that the O-methylation of macakurzin C to generate compound 6 significantly disrupted PPARδ binding. Compound 6 has therapeutic potential in hypoadiponectinemia-related metabolic diseases.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.8
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• pp.1075-1083
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• 2015

Adipose tissue deposited within muscle fibers, known as intramuscular fat (IMF or marbling), is a major determinant of meat quality and thereby affects its economic value. The biological mechanisms that determine IMF content are therefore of interest. In this study, 48 genes involved in the bovine peroxisome proliferator-activated receptor signaling pathway, which is involved in lipid metabolism, were investigated to identify candidate genes associated with IMF in the longissimus dorsi of Hanwoo (Korean cattle). Ten genes, retinoid X receptor alpha, peroxisome proliferator-activated receptor gamma (PPARG), phospholipid transfer protein, stearoyl-CoA desaturase, nuclear receptor subfamily 1 group H member 3, fatty acid binding protein 3 (FABP3), carnitine palmitoyltransferase II, acyl-Coenzyme A dehydrogenase long chain (ACADL), acyl-Coenzyme A oxidase 2 branched chain, and fatty acid binding protein 4, showed significant effects with regard to IMF and were differentially expressed between the low- and high-marbled groups (p<0.05). Analysis of the gene co-expression network based on Pearson's correlation coefficients identified 10 up-regulated genes in the high-marbled group that formed a major cluster. Among these genes, the PPARG-FABP4 gene pair exhibited the strongest correlation in the network. Glycerol kinase was found to play a role in mediating activation of the differentially expressed genes. We categorized the 10 significantly differentially expressed genes into the corresponding downstream pathways and investigated the direct interactive relationships among these genes. We suggest that fatty acid oxidation is the major downstream pathway affecting IMF content. The PPARG/RXRA complex triggers activation of target genes involved in fatty acid oxidation resulting in increased triglyceride formation by ATP production. Our findings highlight candidate genes associated with the IMF content of the loin muscle of Korean cattle and provide insight into the biological mechanisms that determine adipose deposition within muscle.

• Journal of Applied Biological Chemistry
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• v.60 no.1
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• pp.23-28
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• 2017

Amomum tsao-ko used as a traditional oriental herbal medicine, is indigenous to several Asia countries. In this study, we investigated anti-obesity activity of the ethanol extract of Amomum Taso-ko (A. tsao-ko). The ethanol extract of A. tsao-ko inhibited adipocyte differentiation using Oil Red O assay in 3T3-L1 cells. Inhibitory effect of the ethanol extract of A. tsao-ko on adipogenesis was modulated by down-regulation adipogenic transcriptional factor such as peroxisome proliferator-activated receptor ${\gamma}$ ($PPAR{\gamma}$), CCAAT-enhancer-binding protein ${\alpha}$ ($C/EBP{\alpha}$) and suppressed expression of fatty acid synthase, aP2, and resistin. We demonstrated that A. tsao-ko significantly inhibited adipogenesis and reduced $PPAR{\gamma}$ and $C/EBP{\alpha}$ expression in a dose-dependent manner. These results suggest that A. tsao-ko has an anti-obesity effect by inhibition of adipogenic transcription factor and adipocyte-specific genes in 3T3-L1 cells.

• The Korea Journal of Herbology
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• v.20 no.2
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• pp.91-102
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• 2005

Objectives : By examining the effects of Jwa Kum-Whan composed of Coptidis Rhizoma and Evodiae Fructus by the ratio of 6:1 the effects of Soo Ryeon-Whan and composed of Coptidis Rhizoma and Evodiae Fructus by the ratio of 1:1 on hyperlipidemia, the present study attempted to reveal the change of effects based on the ratio of combination. Methods : Jwa Kum-Whan and Soo Ryeon-Whan were injected to rats suffered from induced hyperlipidemia, and then its influence on lipid. During the cultivation of hepatocytes, Jwa Kum-Whan and Soo Ryeon-Whan were added to culture media, and the expression of the enzymes relevant to fat metabolism of hepatocytes was examined. Results : 1. Jwa Kum-Whan significantly decreased total cholesterol(Tc), triglyceride(TG), and LDL-cholesterol(LDLc) of rats suffering from hyperlipidemia induced by high cholesterol diet. Soo Ryeon-Whan decreased LDLc, but had no significant on Tc and TG. 2. Jwa Kum-Whan increased the expression of cholesterol esterase, LDL-receptor, diacylglycerol acyltransferase (DGAT), acylCoA-cholesterol-acyltransferase (ACAT), peroxisome proliferator activated receptor gamma $(PPAR{\gamma})$, peroxisome proliferator activated receptor alpha $(PPAR{\alpha})$ of cultivated hepatocytes. In addition, Soo Ryeon-Whan increased the expression of cholesterol esterase, LDL-Receptor, DGAT, $PPAR{\gamma},\;PPAR{\alpha}$ of cultivated hepatocytes, but had no significant effects on the expression of ACAT. Conclusion : Both Jwa Kum-Whan and Soo Ryeon-Whan were composed of Coptidis Rhizoma and Evodiae Fructus, but the fonner is more effective in hyperlipidemia.

• The Korean Journal of Physiology and Pharmacology
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• v.20 no.5
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• pp.459-466
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• 2016

Adipogenic differentiation of mesenchymal stem cells (MSCs) is critical for metabolic homeostasis and nutrient signaling during development. However, limited information is available on the pivotal modulators of adipogenic differentiation of MSCs. Adaptor protein Lnk (Src homology 2B3 [SH2B3]), which belongs to a family of SH2-containing proteins, modulates the bioactivities of different stem cells, including hematopoietic stem cells and endothelial progenitor cells. In this study, we investigated whether an interaction between insulin-like growth factor-1 receptor (IGF-1R) and Lnk regulated IGF-1-induced adipogenic differentiation of MSCs. We found that wild-type MSCs showed greater adipogenic differentiation potential than $Lnk^{-/-}$ MSCs. An ex vivo adipogenic differentiation assay showed that $Lnk^{-/-}$ MSCs had decreased adipogenic differentiation potential compared with wild-type MSCs. Interestingly, we found that Lnk formed a complex with IGF-1R and that IGF-1 induced the dissociation of this complex. In addition, we observed that IGF-1-induced increase in the phosphorylation of Akt and mammalian target of rapamycin was triggered by the dissociation of the IGF-1R-Lnk complex. Expression levels of a pivotal transcription factor peroxisome proliferator-activated receptor gamma ($PPAR-{\gamma}$) and its adipogenic target genes (LPL and FABP4) significantly decreased in $Lnk^{-/-}$ MSCs. These results suggested that Lnk adaptor protein regulated the adipogenesis of MSCs through the $IGF-1/Akt/PPAR-{\gamma}$ pathway.