• International Journal of Oral Biology
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• v.43 no.1
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• pp.29-35
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• 2018

It is noted that chalcone derivatives have characteristic diverse pharmacological properties, and that precise evidence has been growing that they could regulate a tumor necrosis $factor-{\alpha}$ ($TNF-{\alpha}$) induced insulin resistance. The purpose of the present investigation is to elucidate the effects of the identified chalcone derivatives on adipogenesis, and to find the underlying mechanism of action in that case. Consequently, we first investigated whether the chalcone derivatives could affect the identified $PPAR{\gamma}$-induced transcriptional activity on the proliferator-activated receptor response elements (PPRE) at target promoters, and find that trans-chalcone most significantly increased the $PPAR{\gamma}$-induced transcriptional activity. Additionally, we confirmed that there were up-regulatory effects of trans-chalcone during the adipogenesis and lipid accumulation, and on the mRNA of adipogenic factors in 3T3-L1 cells. Next, we examined the effect of trans-chalcone on the inhibition induced by $TNF-{\alpha}$ on adipogenesis. To that end, we noted that the treatment with trans-chalcone attenuated the effect of $TNF-{\alpha}$ mediated secretion of various adipokines that are involved in insulin sensitivity. For this reason, we noted that this study clearly demonstrates that trans-chalcone enhanced adipogenesis, in part, by its potent effect on $PPAR{\gamma}$ activation and by its reverse effect on $TNF-{\alpha}$.

• Food Science of Animal Resources
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• v.30 no.5
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• pp.787-794
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• 2010

Calcium plays a role as a signaling molecule in various cellular events. It has been reported that calcium suppresses adipocyte differentiation only in the early phase of adipogenesis. Herein, we demonstrate that treatment of A23187, a mobilizer of intracellular calcium, on day 4 post adipocyte differentiation could still reduce lipid accumulation in differentiating 3T3-L1 cells for 48 h. In addition, luciferase reporter gene and RT-Q-PCR assays demonstrate that A23187 can selectively inhibit transcriptional activities and expression of PPAR$\gamma$ and LXR$\alpha$, suggesting that A23187 may reduce lipid accumulation in the late phase of adipogenesis via downregulation of PPAR$\gamma$ and LXR$\alpha$ expression and transactivation. Moreover, inhibition of HDAC activity by trichostatin A (TSA) partially blocked A23187-mediated downregulation of transcriptional activities of PPAR$\gamma$ and LXR$\alpha$. Together, our data demonstrate that calcium mobilization inhibits expression and transcriptional activities of PPAR$\gamma$ and LXR$\alpha$, resulting in reduced lipid accumulation in differentiating adipocytes, and thus, mobilization of intracellular calcium in adipocytes may serve as a new preventive and therapeutic approach for obesity.

• YAKHAK HOEJI
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• v.54 no.2
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• pp.91-96
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• 2010

Berberine, an isoquinoline alkaloid, has a wide range of pharmacological effects, including anti-inflammation. It has been reported that berberine inhibits experimental colitis through inhibition of IL-8, and that inhibitory effect of berberine on inflammatory cytokine expression is mediated through peroxisome proliferator activated receptor (PPAR)-$\gamma$. In this study, we examined the effects and action mechanism of berberine on the tumor necrosis factor (TNF)-$\alpha$-induced monocyte adhesion to HT29 human colonic epithelial cells, which is commonly used as an in vitro model of inflammatory bowel disease (IBD). Berberine significantly inhibited the TNF-$\alpha$-induced monocyte adhesion to HT29, which is similar to the effect of PDTC, a nuclear factor (NF)-$\kappa$B inhibitor. However, ciglitazone and GW, the ligands of PPAR-$\gamma$, did not suppress the TNF-$\alpha$-induced monocyte adhesion to HT29 cells. In addition, TNF-$\alpha$-induced chemokine expression and NF-$\kappa$B transcriptional activity were significantly inhibited by berberine in a concentration-dependent manner. The results suggest that inhibitory effect of berberine on colitis is mediated through suppression of NF-$\kappa$B and NF-$\kappa$B-dependent chemokine expression.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.7
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• pp.963-971
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• 2014

This study investigated the effects of exercise intensity on PGC-$1{\alpha}$, PPAR-${\gamma}$, and insulin resistance in skeletal muscle of high fat diet-fed Sprague-Dawley rats. Forty rats were randomly divided into five groups: sedentary control group (SED), high fat diet group (HF), high fat diet+low-intensity exercise group (HFLE, 22 m/min, 60 min, 6 days/week), high fat diet+moderate-intensity exercise group (HFME, 26 m/min, 51 min), and high fat diet+high-intensity exercise group (HFHE, 30 m/min, 46 min). After 4 weeks of high fat diet and endurance exercise training, the lipid profiles, insulin, and glucose concentrations were determined in plasma. PGC-$1{\alpha}$, PPAR-${\gamma}$, and GLUT-4 contents were measured in plantaris muscle. The rate of glucose transport in soleus muscle was determined under submaximal insulin concentration ($1,000{\mu}IU/mL$ insulin, 20 min) during muscle incubation. Plasma glucose during oral glucose tolerance test in HF was significantly greater than that in SED, and plasma glucose levels in the three exercise (EX) groups were significantly lower that those in SED and HF at 30 and 60 min, respectively (P<0.05). Plasma insulin levels in the EX groups were significantly reduced by 60 min compared to that in HF (P<0.05). The protein expression level of PGC-$1{\alpha}$ as well as muscle glucose uptake were significantly higher in SED and HF than those in the three EX groups (P<0.05), and HFHE showed significantly higher levels than HFLE and HFME. Expression levels of GLUT-4 and PPAR-${\gamma}$ were significantly higher in the HFLE, HFME, and HFHE groups compared to the SED and HF (P<0.05). Therefore, the results of this study indicate that 4 weeks of high fat diet significantly developed whole body insulin resistance but did not affect PGC-$1{\alpha}$, PPAR-${\gamma}$, or the glucose transport rate in skeletal muscle, and exercise training was able to attenuate deteriorated whole body insulin resistance due to high fat diet. In addition, high intensity training significantly affected PGC-$1{\alpha}$ expression and the glucose transport rate of skeletal muscle in comparison with low and middle training intensities.

• Journal of Life Science
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• v.19 no.11
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• pp.1637-1643
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• 2009

Shikonin, a component of Lithospermum erythrorhizon Sieb. et Zucc, exerts various characteristics such as anti-inflammatory, anti-cancer and anti-obesity functions. To elucidate the molecular mechanism of shikonin-induced inhibition of adipogenesis, we analyzed the mRNA expression level of various adipogenesis-related factors including C/EBPs (CCAAT/enhancerbinding proteins) and $PPAR{\gamma}$ (peroxisome proliferator-activated receptor $\gamma$). The data showed that mRNA expressions of C/$EBP{\beta}$ and C/$EPB{\delta}$ were only slightly changed by shikonin treatment, but mRNA expressions of $PPAR{\gamma}$ and C/$EPB{\alpha}$ were significantly down-regulated. Then, we tested whether upstream regulators of C/$EBP{\beta}$ and $PPAR{\gamma}$ were involved in anti-adipogenesis of shikonin. C/$EBP{\gamma}$ and CHOP (C/EBP homologous protein), which are upstream regulators of C/$EBP{\beta}$, were not affected by shikonin treatment. On the contrary, the mRNA level of KROX20 was markedly down-regulated by shikonin treatment. These results suggest that KROX20 might regulate downstream factors of adipogenesis through C/$EBP{\beta}$-independent pathway. The expression of KLF15 (Kruppel-like factor15), which is a member of KLF family and is a upstream regulator of $PPAR{\gamma}$, was dramatically decreased by shikonin treatment, but KLF2 was not changed. Shikonin had no impact on the expression of KLF5 in the early stage of adipogenesis, but shikonin increased expression of KLF5 in the late stage of adipogenesis. Even though mRNA expression of KLF5 was moderately changed by shikonin treatment, its effect may be small compared with the effect of KLF15, which was markedly inhibited. Taken together, these results suggest that shikonin inhibits adipogenesis through the down-regulation of $PPAR{\gamma}$ and C/$EPB{\alpha}$, which is mediated by the down-regulation of two pro-adipogenic factors, KROX20 and KLF15.

• Journal of Nutrition and Health
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• v.40 no.3
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• pp.221-228
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• 2007

We determined the effects of dietary manipulations on messenger RNA of peroxisome proliferators activated receptor isoforms (i.e., PPAR ${\alpha},\;{\beta}/{\delta},\;{\gamma}$) in red vastus lateralis muscle of rats. Total 16 male Sprague-Dawley rats were used, and animals were divided into one of two dietary conditions: either chow diet group (CHOW; n=8) in which animals were 134 with standard rodent chow (61.8% carbohydrate, 15.7% fat, 22.5% protein) or high fat diet group (FAT n=8) in which animals were fed 24.3% carbohydrate, 52.8% fat, 22.9% protein. At the end of the 8 weeks of experimental period, red vastus lateralis muscle was dissected out from all animals, and PPAR ${\alpha},\;{\beta}/{\delta},\;{\gamma}$ mRNA expression was determined. There was no significant difference in body mass (BM) between CHOW and FAT. As expected, blood glucose and free fatty acid (FFA) concentration was higher in FAT than CHOW (p<0.05), and lactate concentration was significantly lower in FAT compared to CHOW (p<0.05). Insulin concentration tended to higher in FAT than CHOW ($67.2{\pm}21.9\;vs.\;27.0{\pm}5.2$ pmol/L), but it did not reach to the statistical significance. Gene expression of PPAR ${\alpha}$ was not significantly different between CHOW and FAT. It was not also significantly different in PPAR ${\beta}/{\delta}$. Interestingly, expression of mRNA in PPAR ${\gamma}$ however, was markedly depressed in FAT compared to CHOW (approximately 3 fold higher in CHOW; p<0.05). Results obtained from present study implies that PPAR ${\gamma}$ (as compensatory function of PPAR ${\alpha}$ is expressed) possibly exerts another major tuning roles in fatty acid transport, utilization, as well as biosynthesis in skeletal muscle cells. The situations and conditions that can be postulated for this implication need to be further examined.

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2002.11a
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• pp.14-40
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• 2002

15-Deoxy-${\Delta}^{12, 14}$-prostaglandin $J_2$ (15-deoxy-$PGJ_2$), a naturally occurring ligand activates the peroxisome proliferator-activated $receptor-{\gamma}(PPAR-{\gamma}$). Activation of $PPAR-{\gamma}$ has been found to induce cell differentiation such as adipose cell and macrophage. Here it was investigated whether 15-deoxy-$PGJ_2$ has neuronal cell differentiation and possible underlying molecular mechanisms. Dopaminergic differentiating PC 12 cells treated with 15-deoxy-$PGJ_2$ (0.2 to 1.6 ${\mu}M$) alone showed measurable neurite extension and expression of neurofilament, markers of cell differentiation. However much greater extent of neurite extension and expression of neurofilament was observed in the presence of NGF (50 ng/ml). In parallel with its increasing effect on the neurite extension and expression of neurofilament, 15-deoxy-$PGJ_2$ enhanced NGF-induced p38 MAP kinase expression and its phosphorylation in addition to the activation of transcription factor AP-1 in a dose dependent manner. Moreover, pretreatment of SD 203580, a specific inhibitor of p38 MAP kinase inhibited the promoting effect of 15-deoxy-$PGJ_2$(0.8 ${\mu}M$) on NGF-induced neurite extension. This inhibition correlated well with the ability of SB203580 to inhibit the enhancing effect of 15-deoxy-$PGJ_2$ on the expression of p38 MAP kinase and activation of AP-1, The promoting ability of 15-deoxy-$PGJ_2$ did not occur through $PPAR-{\gamma}$, as synthetic PPAR-${\gamma}$ agonist andantagonist did not change the neurite promoting effect of 15-deoxy-PGJ$_2$. In addition, contrast to other cells (embryonic midbrain and SK-N-MC cells), $PPAR-{\gamma}$ was not expressed in PC-12 cells. Other structure related prostaglandins, PGD$_2$ and $PGE_2$ acting via a cell surface G-protein-coupled receptor (GPCR) did not increase basal or NGF-induced neurite extension. Moreover, GPCR (EP and DP receptor) antagonists did not alter the promoting effect of f 5-deoxy-$PGJ_2$ on neurite extension and activation of p38 MAP kinase, suggesting that the promoting effect of 15-deoxy-$PGJ_2$ may not be mediated GPCR. These data demonstrate that activation of p38 MAP kinase in conjunction with AP-1 single pathway may be important in the promoting activity of 15-deoxy-$PGJ_2$ cells.

• Clinical and Experimental Reproductive Medicine
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• v.40 no.2
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• pp.67-75
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• 2013

Objective: To investigate the effect of peroxisome proliferator activated receptor ${\gamma}$(PPAR${\gamma}$) agonist on the cell proliferation properties and expression of human telomerase reverse transcriptase (hTERT) and aromatase in cultured endometrial stromal cell (ESC) from patients with endometriosis. Methods: Human endometrial tissues were obtained from women with endometriosis and healthy women (controls) using endometrial biopsy. Isolated ESCs were cultured and the cell proliferation was measured by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide assay and expression of hTERT, aromatase, and cyclooxygenase (COX)-2 by western blotting according to the addition of rosiglitazone (PPAR${\gamma}$ agonist). Results: We demonstrate that the cultured ESCs of endometriosis showed hTERT protein overexpression and increased cellular proliferation, which was inhibited by rosiglitazone, in a dose-dependent manner. At the same time, PPAR${\gamma}$ agonist also inhibited aromatase and COX-2 expression, resulting in decreased prostaglandin $E_2$ production in the ESCs of endometriosis. Conclusion: This study suggests that PPAR${\gamma}$ agonist plays an inhibitory role in the proliferative properties of eutopic endometrium with endometriosis by down-regulation of hTERT and COX-2 expression; this could be a new treatment target for endometriosis.

• Journal of Veterinary Clinics
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• v.31 no.6
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• pp.469-476
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• 2014

The aims of this study were to explore the effects of conjugated linoleic acid (CLA) on reactive oxygen species (ROS) production in lipopolysaccharide (LPS)-naïve and LPS-stimulated RAW 264.7 macrophages and to examine whether these effects affect the regulation of tumor necrosis factor-alpha (TNF-${\alpha}$) production, and nuclear factor-kappa B (NF-${\kappa}B$) and peroxisome proliferator-activated receptor gamma ($PPAR{\gamma}$) activation. Trans-10, cis-12(t10c12)-CLA increased the production of ROS, as well as TNF-${\alpha}$ in LPS-naïve RAW 264.7 cells. The CLA-induced TNF-${\alpha}$ production was suppressed by treatment of diphenyleneiodonium chloride (DPI), a NADPH oxidase inhibitor. In addition, CLA enhanced the activities of NF-${\kappa}B$ and $PPAR{\gamma}$ in LPS-naïve RAW 264.7 cells, and this effect was abolished with DPI treatment. LPS treatment increased ROS production, whereas CLA reduced LPS-induced ROS production. LPS increased both TNF-${\alpha}$ production and NF-${\kappa}B$ activity, whereas t10c12-CLA reduced TNF-${\alpha}$ production and NF-${\kappa}B$ activity in LPS-stimulated RAW 264.7 cells. DPI treatment suppressed LPS-induced ROS production and NF-${\kappa}B$ activity. Moreover, DPI enhanced the inhibitory effects of t10c12-CLA on TNF-${\alpha}$ production and NF-${\kappa}B$ activation in LPS-stimulated RAW 264.7 cells. However, neither t10c12-CLA nor DPI affected $PPAR{\gamma}$ activity in LPS-stimulated RAW 264.7 cells. Taken together, these data indicate that t10c12-CLA induces TNF-${\alpha}$ production by increasing ROS production in LPS-naïve RAW 264.7 cells, which is mediated by the enhancement of NF-${\kappa}B$ activity via $PPAR{\gamma}$ activation. By contrast, t10c12-CLA suppresses TNF-${\alpha}$ production by inhibiting ROS production and NF-${\kappa}B$ activation via a $PPAR{\gamma}$-independent pathway in LPS-stimulated RAW 264.7 cells. These results suggest that t10c12-CLA can modulate TNF-${\alpha}$ production and NF-${\kappa}B$ activation through formation of ROS in RAW 264.7 macrophages.

• Natural Product Sciences
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• v.28 no.2
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• pp.80-88
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• 2022

Colorectal cancer is one of the most common cancers globally, ranking second for the number of cancer-related deaths. Metastasis has been reported as the main cause of death in patients with colorectal cancer. Peroxisome proliferator-activated receptor gamma (PPAR-γ) is a transcription factor that functions as a tumor suppressor by inhibiting cellular proliferation, migration, and invasion. In our previous efforts to generate natural product-motivated PPAR-γ ligands, the compounds 1 and 2 were obtained. These compounds activated PPAR-γ and inhibited the migration and invasion of HCT116 colorectal cancer cells, and they were also found to inhibit the epithelial-to-mesenchymal transition, which is a key process in cancer metastasis. Compounds 1 and 2 upregulated expression of the epithelial marker (E-cadherin), and downregulated expression of the mesenchymal marker (N-cadherin) and transcriptional factor (Snail). Therefore, the PPAR-γ agonists 1 and 2 could serve as a valuable model for the study on anti-metastatic leads for the treatment of colorectal cancer.