Preventive Effect of Fermented Chestnut Inner Shell Extract on Obesity-Induced Hepatic Steatosis.

This study aimed to investigate the effects of the gallic acid-enriched fermented chestnut inner shell extract (FCCE) by Saccharomyces cerevisiae on a high fat diet (HFD)-induced obesity and hepatic steatosis in vivo mouse model. Mice feeding FCCE exhibited reduced body weight gain compared to those in the HFD-fed group, and showed lower abdominal fat pad weight including epididymal, retroperitoneal, and mesenteric adipose tissue. Further, FCCE administration decreased adipocyte size by suppressing adipogenic factors such as peroxisome proliferator activated receptor γ and CCAAT/ enhancer-binding protein α, and lipogenic factors such as sterol regulatory element-binding protein-1c, fatty acid synthase, and stearoyl CoA desaturase-1. Moreover, FCCE decreased levels of lipids in serum and liver as well as serum alanine aminotransferase and aspartate aminotransferase levels, markers of liver injury. Histological observations of the liver showed that FCCE significantly attenuated HFD-induced hepatic steatosis. The effect of FCCE on hepatic lipid regulatory factors may be partly associated with adenosine monophosphate-activated protein kinase activation. These results suggest that gallic acid-enriched FCCE has potential to be a promising functional food for prevention of obesity and obesity-related fatty liver disease.

Fermented Castanea crenata Inner Shell Extract Increases Fat Metabolism and Decreases Obesity in High-Fat Diet-Induced Obese Mice.

The anti-obesity effects of fermented Castanea crenata inner shell extract (FCCE) were investigated using high-fat diet (HFD)-induced obese mice. In the FCCE intake groups, body weight gain and adipocyte area were significantly reduced, especially body weight gain in the 250 mg/kg FCCE group (G4) decreased by 37%, respectively, compared with negative control group (G2, HFD group). After oral administration of the FCCE, the increase of serum low-density lipoprotein (LDL)-cholesterol induced by HFD was suppressed significantly, as well as the level of aspartate aminotransferase, and alanine aminotransferase, which are markers of hepatitis induced by obesity. Serum leptin in G4 group was significantly decreased to less than that of G2 group. Also, in G4 and 500 mg/kg FCCE group (G5), enzymes-related lipogenesis, citrate synthase, and ATP citrate lyase were decreased, whereas the level of enoyl-CoA hydratase used for ß-oxidation was significantly increased in comparison with normal diet group. Furthermore, the FCCE stimulated the expression of lipolytic regulators, especially AMP-activated protein kinase. In conclusion, we suggest that the FCCE may ameliorate in diet-induced obesity by regulating lipid metabolism.

Germinated Waxy Black Rice Ameliorates Hyperglycemia and Dyslipidemia in Streptozotocin-Induced Diabetic Rats.

This study aimed to examine the anti-diabetic effect of germinated waxy black rice (GWBR) using streptozotocin (STZ)-induced diabetic rats. In the diabetic rats, GWBR supplementation for 8 weeks reduced plasma blood glucose concentrations, improved glucose clearance and prevented diabetes-induced weight loss. Rats with STZ-induced diabetes who received GWBR supplementation exhibited decreased expression of sodium-dependent glucose transporter 1 (SGLT1) and glucose transporter (GLUT) 2 genes and proteins in the small intestine via decreases in hepatocyte nuclear factor (HNF)-1α, HNF-1ß, and HNF-4α, transcriptional factors that are involved in the regulation of SGLT1 and GLUT2, compared with the rats with STZ-induced diabetes that did not receive GWBR supplements. GWBR supplementation also enhanced the expression of GLUT4 and the genes and proteins involved in GLUT4 translocation, such as insulin receptor (IR) and insulin receptor substrate 1 (IRS1), and increased the phosphorylation of phosphoinositide 3-kinase (PI3K) and protein kinase B (PKB, Akt) proteins in skeletal muscle. GWBR further increased glycogen synthase (GS) 1 by decreasing glycogen synthase kinase (GSK)-3ß in skeletal muscle. Interestingly, GWBR recovered STZ-impaired pancreatic ß-cells, resulting in increased insulin synthesis and secretion. In addition, GWBR reduced serum triglyceride, total cholesterol, low-density lipoprotein cholesterol, aspartate transferase and alanine transferase concentrations and increased high-density lipoprotein cholesterol concentrations. Taken together, these findings suggest that GWBR could be a candidate for improving the diabetic condition by regulating glucose uptake in the intestine and muscle and regulating the secretion of insulin from the pancreas.

Kefir prevented excess fat accumulation in diet-induced obese mice.

Excessive body fat accumulation can result in obesity, which is a serious health concern. Kefir, a probiotic, has recently shown possible health benefits in fighting obesity. This study investigated the inhibitory effects of 0.1 and 0.2% kefir powder on fat accumulation in adipose and liver tissues of high-fat diet (HFD)-induced obese mice. Kefir reduced body weight and epididymal fat pad weight and decreased adipocyte diameters in HFD-induced obese mice. This was supported by decreased expression of genes related to adipogenesis and lipogenesis as well as reduced proinflammatory marker levels in epididymal fat. Along with reduced hepatic triacylglycerol concentrations and serum alanine transaminase and aspartate transaminase activities, genes related to lipogenesis and fatty acid oxidation were downregulated and upregulated, respectively, in liver tissue. Kefir also decreased serum triacylglycerol, total cholesterol, and low-density lipoprotein-cholesterol concentrations. Overall, kefir has the potential to prevent obesity.

Antiobesity Effect of Garlic Extract Fermented by Lactobacillus plantarum BL2 in Diet-Induced Obese Mice.

Obesity is viewed as a serious public health problem. This study aimed to investigate the antiobesity effects of fermented garlic extract by lactic acid bacteria (LAFGE) on obesity. Male C57BL/6J mice were fed with high-fat diet (HFD) to induce obesity. The HFD-induced obese mice were orally administrated with 250 or 500 mg/kg LAFGE for 8 weeks. Feeding HFD-fed mice with 250 or 500 mg/kg LAFGE reduced body weight by 14% and 18%, respectively, compared to HFD. HFD-fed mice with 500 mg/kg LAFGE administration had lower epididymal, retroperitoneal, and mesenteric adipose tissue mass by 36%, 44%, and 63%, respectively, compared to HFD. The concentration of plasma triacylglyceride and total cholesterol was significantly lower in the HFD-fed mice with LAFGE administration. Moreover, LAFGE supplementation suppressed adipogenesis by downregulation in mRNA and protein expression of PPARγ, C/EBPα, and lipogenic proteins, including SREBP-1c, FAS, and SCD-1. Based on these findings, LAFGE may ameliorate diet-induced obesity by inhibiting adipose tissue hypertrophy by suppressing adipogenesis.

Germinated Waxy Black Rice Suppresses Weight Gain in High-Fat Diet-Induced Obese Mice.

This study was performed to investigate the antiobesity effect of germinated waxy black rice (GWBR) in high-fat diet (HFD)-induced obese mice. The mice were divided into a normal diet (ND) group, HFD group, and 2 test groups for 8 weeks: 2.5% GWBR-supplemented (GWBR-2.5) group and 5% GWBR-supplemented (GWBR-5) group. Supplementing with GWBR significantly reduced body weight gain and lipid accumulation in the liver and adipose tissue compared to the HFD control group. Triglyceride (TG), total cholesterol, and low-density lipoprotein-cholesterol levels in serum were decreased by GWBR supplementation, whereas high-density lipoprotein-cholesterol level significantly increased. In addition, mRNA levels of transcriptional factors, such as peroxisome proliferator-activated receptor-γ, CCAAT enhancer-binding protein (C/EBP)-α, C/EBP-ß, sterol regulatory element-binding protein-1c, and related genes, including adipocyte fatty acid-binding protein, fatty acid synthase, and lipoprotein lipase, were significantly lower in the GWBR groups. However, lipolytic enzymes, such as hormone-sensitive lipase, adipose TG lipase, and carnitine palmitoyltransferase-1, and uncoupling protein 2 mRNA levels were significantly higher in GWBR-supplemented mice. These results suggest that GWBR exerts antiobesity effects by decreasing lipid accumulation and promoting lipolysis in HFD-induced obese mice.

Germinated waxy black rice extract inhibits lipid accumulation with regulation of multiple gene expression in 3T3-L1 adipocytes.

The aim of this study was to investigate the anti-obesity effects of germinated waxy black rice (GWBR) extract in 3T3-L1 adipocytes. The inhibitory effect of GWBR extract against adipocyte differentiation was evaluated using Oil Red O staining and glycerol-3-phosphate dehydrogenase (GPDH) assay. GWBR extract inhibited adipocyte differentiation, but was not found to elicit any cytotoxicity. The mRNA levels of adipogenic transcriptional factors such as C/EBP-α and -ß, PPAR-γ, and SREBP-1c, as well as adipogenic enzymes, including aP2, LPL, and FAS were significantly downregulated by treatment with GWBR extract compared to untreated control cells. However, mRNA levels of lipolytic genes such as HSL and ATGL, ß-oxidation related genes CPT1, and UCP2 involved in thermogenesis were significantly up-regulated by treatment with GWBR extract. These data suggest that GWBR extract may be a potential functional food, and may have pharmacological applications in both the prevention and treatment of obesity.

Hepatoprotective effects of lactic acid-fermented garlic extract against acetaminophen-induced acute liver injury in rats.

The aim of the present study was to investigate the protective effect of fermented garlic extract by lactic acid bacteria (LAFGE) against acetaminophen (AAP)-induced acute liver injury in rats. Here we demonstrated that rats treated with LAFGE exhibit resistance to AAP-induced liver injury accompanied by lowered plasma alanine amino transferase levels and decreased proinflammatory responses. This function of LAFGE is linked to its capacity of suppressing AAP-induced apoptosis in the liver, partly via the inhibition of MAPK phosphorylation as well as down-regulation of p53. Our findings reveal that LAFGE modulates the signaling pathways involved in hepatic apoptosis through cellular redox control, as indicated by the inhibition of lipid peroxidation, glutathione and ATP depletion, and the elevation of antioxidant enzyme activities. Taken together, these findings indicate that LAFGE ameliorates AAP-induced liver injury by preventing oxidative stress-mediated apoptosis, thereby establishing LAFGE as a potential supplement in the treatment of AAP-induced liver injury.

Germinated brown rice extract inhibits adipogenesis through the down-regulation of adipogenic genes in 3T3-L1 adipocytes.

The aim of this study was to examine the anti-adipogenic effect of germinated brown rice methanol extract (GBR) in 3T3-L1 adipocytes. The GBR inhibited adipocyte differentiation was measured by Oil Red O staining and glycerol-3-phosphate dehydrogenase (GPDH) activity in a dose-dependent manner without initiating any cytotoxicity. The mRNA levels of adipogenic transcription factors such as CCAAT/enhancer binding protein (C/EBPα), proliferator-activated receptorγ (PPARγ), and sterol regulatory element-binding protein-1c (SREBP-1c), and adipogenic genes, such as fatty acid synthase (FAS), adipocyte fatty acid-binding protein (aP2), and lipoprotein lipase (LPL), were significantly down-regulated by treatment with GBR when compared to that of untreated control cells. Moreover, tumor necrosis factor-α (TNF-α) and interlukin-6 (IL-6) mRNA expressions were attenuated by GBR in mature adipocytes. These data suggest that GBR exhibits an anti-adipogenic effect through the suppression of adipogenesis in 3T3-L1 adipocytes.

Kefir inhibits 3T3-L1 adipocyte differentiation through down-regulation of adipogenic transcription factor expression.

BACKGROUND: Kefir, a traditional fermented milk composed of microbial symbionts, is reported to have various health benefits such as anti-tumour, anti-inflammatory, anti-neoplastic and pro-digestive effects. In this study, to elucidate the effects of kefir on adipocyte differentiation and lipid accumulation, three fractions were prepared from kefir culture broth. The inhibitory effects of kefir liquid culture broth fraction (Fr-1), soluble fraction (Fr-2) and insoluble fraction (Fr-3), prepared by sonication of kefir solid culture broth, on adipocyte differentiation in 3T3-L1 preadipocytes were examined. RESULTS: Fr-3 (0.1 mg mL(-1)) significantly decreased lipid accumulation and glycerol-3-phosphate dehydrogenase (GPDH) activity by 60 and 68% respectively without affecting cell viability. In addition, Fr-3 treatment down-regulated the mRNA expression of adipogenic transcription factors including C/EBPα (32%), PPARγ (46%) and SREBP-1c (34%) during adipocyte differentiation compared with untreated control cells. The mRNA expression of adipocyte-specific genes (aP2, FAS and ACC) was also clearly decreased. CONCLUSION: The results suggest that the insoluble fraction of kefir (Fr-3) mediates anti-adipogenic effects through the inhibition of adipocyte differentiation, partly via suppression of the C/EBPα-, SREBP-1c- and PPARγ-dependent pathways.

Anti-obesity effects of germinated brown rice extract through down-regulation of lipogenic genes in high fat diet-induced obese mice.

Lipid accumulation using Oil Red O dye was measured in 3T3-L1 murine adipocytes to examine the anti-obesity effect of four types of germinated rice, including germinated brown rice (GBR), germinated waxy brown rice (GWBR), germinated black rice (GB-R), and germinated waxy black rice (GWB-R). GBR methanol extract exhibited the highest suppression of lipid accumulation in the 3T3-L1 cell line and also the anti-obesity effect of GBR on high fat induced-obese mice. The mice were divided into three groups and were administered: ND, a normal diet; HFD control, a high fat diet; and GBR, a high fat diet plus 0.15% GBR methanol extract for 7 weeks. GBR administration significantly decreased body weight gain and lipid accumulation in the liver and epididymal adipose tissue as compared to the HFD control group. In addition, serum triglycerides (TGs) and total cholesterol (TC) levels were significantly decreased by following GBR administration compared with those in the HFD control group, whereas the high-density lipoprotein (HDL) cholesterol level increased. Furthermore, the mRNA levels of adipogenic transcriptional factors, such as CCAAT enhancer binding protein (C/EBP)-α, sterol regulatory element-binding protein (SREBP)-1c, and peroxisome proliferator activated receptors (PPAR)-γ, and related genes (aP2, FAS), decreased significantly. Taken together, GBR administration suppressed body weight gain and lipid accumulation in the liver and epididymal adipocytes, and improved serum lipid profiles, in part, by controlling adipogenesis through a reduction in transcriptional factors. These results suggest that GBR is a potential agent against obesity.

Effects of methoxsalen from Poncirus trifoliata on acetylcholinesterase and trimethyltin-induced learning and memory impairment.

Previously, we identified methoxsalen (8-methoxy-2',3',6,7-furocoumarin) as the bioactive compound probably responsible for acetylcholinesterase (AchE) inhibition achieved by feeding crude extract of Poncirus trifoliate. To confirm the activity of methoxsalen, Institute of Cancer Research (ICR) mice were fed a control or a methoxsalen-supplemented diet for 4 weeks, and then learning and memory enhancing effects with respect to trimethyltin (TMT)-induced neurotoxicity were evaluated. The brain tissues of ICR mice were dissected after completion of the behavioral tests for biochemical analysis. Methoxsalen effectively reversed TMT-induced memory impairment on both Y-maze and passive avoidance tests. Brain AchE activity was inhibited by the oral consumption of all concentrations of methoxsalen. Moreover, the level of oxidative stress was significantly ameliorated in the groups on methodsalen containing diets. This is the first in vivo study conducted with methoxsalen in the field of AD research, and it indicates that further investigation of methoxsalen is warranted.

Inhibitory effect of pomegranate on intestinal sodium dependent glucose uptake.

Intestinal glucose uptake is mainly performed by its specific transporters, SGLT1 and GLUTs expressed in the intestinal epithelial cells. By using Caco-2 cells and 2-NBDG, we observed that intestinal glucose uptake was markedly inhibited by pomegranate (Punica granatum L, PG) among 200 screened edible Korean plants. The effects of the PG extract on Na(+)-dependent glucose uptake were further evaluated using brush border membrane vesicles (BBMV) obtained from the mouse small intestine. PG inhibited Na(+)-dependent glucose uptake with the IC(50) value of 424 µg/ml. The SGLT1 protein expression was dose dependently down regulated with PG treatment in Caco-2 cells. We next assessed the antihyperglycemic effect of PG in streptozotocin (STZ)-induced diabetic mice. Administration of PG (800 mg/kg) to STZ mice for four weeks improved postprandial glucose regulation. Furthermore, elevated Na(+)-dependent glucose uptake by BBMV isolated from STZ mice was normalized by PG treratment. These results suggest that PG could play a role in controlling the dietary glucose absorption at the intestinal tract by decreasing SGLT1 expression, and may contribute to blood glucose homeostasis in the diabetic condition.

Punica granatum protects against oxidative stress in PC12 cells and oxidative stress-induced Alzheimer's symptoms in mice.

Alzheimer's disease (AD) is a progressive degenerative brain disorder that is characterized by neuronal loss, neurofibrillary tangles, and the abnormal deposition of senile plaque and amyloid ß peptide (Aß). The brains of AD patients are under intense oxidative stress. The overproduction of Aß leads to Aß-associated free radical oxidative stress. In this study, the antioxidative and neuronal protective effects of Punica granatum extract were investigated against oxidative stress-induced cytotoxicity in PC12 cells. The ethanol extracts of P. granatum protected PC12 cells from hydrogen peroxide (H2O2-induced oxidative stress. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction assays revealed a significant increase in cell viability when oxidatively stressed PC12 cells were treated with the P. granatum extract. To examine the effects of P. granatum on Aß1₋42-induced learning and memory impairment in mice, in vivo behavioral tests were performed. Treatment with the extract of P. granatum increased step-through latency in mice injected with Aß1₋42. The results of this study suggest that the ethanol extract of P. granatum mitigated H2O2-induced oxidative stress in PC12 cells. In addition, the extract inhibited neuronal cell death caused by Aß-induced oxidative stress and Aß-induced learning and memory deficiency.

Inhibitory effects of Terminalia chebula extract on glycation and endothelial cell adhesion.

Terminalia chebula Retz. has been used in India for a long time to treat many diseases, and its extract was reported to have antidiabetic activity in vivo. In this study, T. chebula methanolic extract (TCE) containing 2.7 % chebulic acid was evaluated for its preventive effects against the formation of advanced glycation end products (AGEs) and endothelial cell dysfunction. When the effects of TCE on AGE formation and on protein crossing-linking by glycation with D-threose and lens crystallines were examined, TCE showed inhibitory activity in a dose-dependent manner, and the concentration of 1000 µg/mL presented an activity similar to that of 5 mM aminoguanidine as a positive control. Upon investigating the protective activity of TCE against AGE-induced vascular endothelium dysfunction, human umbilical vein endothelial cells (HUVEC) incubated with 100 µg/mL of AGEs had significantly enhanced reactive oxygen species (ROS) formation, whereas the treatment of T. chebula reduced AGE-induced ROS generation. The incubation of HUVEC with 100 µg/mL of AGEs caused a considerable increase in THP-1 monocytic cell adhesion, but this adhesion was reduced by the treatment of TCE. These results suggest that TCE is a potential agent for alleviating diabetic complications.

Ipomoea batatas attenuates amyloid ß peptide-induced neurotoxicity in ICR mice.

In this study, the protective effects of 17 Korean native plants against amyloid ß peptide (Aß)-induced oxidative stress were screened using the 2',7'-dichlorofluorescin diacetate assay and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Ipomoea batatas exerted the highest protective effects against oxidative stress and was selected for further investigation. To confirm the protective activity of this extract, the I. batatas extract was fed to ICR mice that had been injected with Aß to induce neuronal deficits. In these experiments, the extract of I. batatas significantly reversed Aß-induced neurotoxicity as assessed by the passive avoidance test, a behavioral experiment. Moreover, I. batatas administration reduced the level of lipid peroxidation and increased catalase activities in biochemical studies using the brain tissue of mice. These results indicate that I. batatas might be beneficial against Alzheimer's disease, especially by limiting oxidative stress in the brain.

In vitro and in vivo hepatoprotective effects of the aqueous extract from Taraxacum officinale (dandelion) root against alcohol-induced oxidative stress.

The protective effects of Taraxacum officinale (dandelion) root against alcoholic liver damage were investigated in HepG2/2E1 cells and ICR mice. When an increase in the production of reactive oxygen species was induced by 300 mM ethanol in vitro, cell viability was drastically decreased by 39%. However, in the presence of hot water extract (TOH) from T. officinale root, no hepatocytic damage was observed in the cells treated with ethanol, while ethanol-extract (TOE) did not show potent hepatoprotective activity. Mice, which received TOH (1 g/kg bw/day) with ethanol revealed complete prevention of alcohol-induced hepatotoxicity as evidenced by the significant reductions of serum aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, and lactate dehydrogenase activities compared to ethanol-alone administered mice. When compared to the ethanol-alone treated group, the mice receiving ethanol plus TOH exhibited significant increases in hepatic antioxidant activities, including catalase, glutathione-S-transferase, glutathione peroxidase, glutathione reductase, and glutathione. Furthermore, the amelioration of malondialdehyde levels indicated TOH's protective effects against liver damage mediated by alcohol in vivo. These results suggest that the aqueous extract of T. officinale root has protective action against alcohol-induced toxicity in the liver by elevating antioxidative potentials and decreasing lipid peroxidation.

Protective effects of kaempferol (3,4',5,7-tetrahydroxyflavone) against amyloid beta peptide (Abeta)-induced neurotoxicity in ICR mice.

To determine the effects of kaempferol, rat pheochromocytoma cells (PC12) and Institute of Cancer Research (ICR) mice were utilized as neuronal models. Using in vitro assays, kaempferol was shown to have protective effects against oxidative stress-induced cytotoxicity in PC12 cells. Administration of kaempferol also significantly reversed amyloid beta peptide (Abeta)-induced impaired performance in a Y-maze test. Taken altogether, the results reported here suggest that further investigation is warranted of the influence of kaempferol on pathways related to Alzheimer's disease.

Differential effects of 5-fluorouracil on glucose transport and expressions of glucose transporter proteins in gastric cancer cells.

Although 5-fluorouracil (5-FU) is a widely used chemotherapeutic agent in the treatment of gastric cancer, the underlying mechanism for 5-FU resistant phenotype, has yet to be elucidated. We hypothesized that the sensitivity of gastric cancer to 5-FU treatment might be related to the rate of glucose transport (GLUT), and investigated the expressions of GLUT1, 2, 3, and 4 in two different gastric cancer cells (SNU-216, moderately differentiated gastric adenocarcinoma; and SNU-668, signet ring cell gastric carcinoma). Immunohistochemistry of GLUT1 and GLUT4 and immunoblot analysis of glycogen synthase kinase 3 were also performed. Hexokinase activity was measured. We found that 5-FU suppressed glucose uptake in SNU-216, while it stimulated GLUT in SNU-668. Further analysis revealed that 5-FU decreased the expression levels of GLUT1, 2, and 4 in SNU-216 cells and increased the expression levels of GLUT1, 2, and 4 in SNU-668 cells. Consistent with GLUT expression levels, immunohistochemistry analysis showed that 5-FU increased GLUT1 and GLUT4 levels in SNU-216 and decreased GLUT1 and GLUT4 levels in SNU-668. We also observed that glycogen synthase kinase 3 activity was decreased in SNU-216 and increased in SNU-668 with 5-FU treatment. No significant difference in hexokinase activities was observed with 5-FU treatment. Taken together, these results suggest that 5-FU exerts differential effects on GLUT depending on gastric cancer cell types, which may indicate a possible explanation, at least in part, for the differing responses to 5-FU chemotherapy in gastric cancer.

Epidermal growth factor increases prostaglandin E2 production via ERK1/2 MAPK and NF-kappaB pathway in fibroblast like synoviocytes from patients with rheumatoid arthritis.

High concentration of epidermal growth factor (EGF) is found in the synovial fluid of rheumatoid arthritis (RA) that might imply the involvement of EGF in the pathogenesis of arthritic diseases. In order to investigate if EGF is involved in the regulation of cyclooxygenase-2 (COX-2) and the prostaglandin E(2) (PGE(2)) production in fibroblast like synoviocytes (FLS) from patients with RA. The levels of COX-2 and microsomal prostaglandin E synthase-1 (mPGES-1) were evaluated using RT-PCR and Western blot analysis. Electrophoretic mobility shift assay (EMSA) was performed to investigate EGF mediated DNA binding activity of nuclear factor-kappaB (NF-kappaB). PGE(2) levels were analyzed by ELISA. EGF enhanced both COX-2 protein and mRNA expressions. mPGES-1 mRNA level was also increased by EGF treatment. EGF also stimulated ERK1/2 MAPK activity and the inhibition of ERK1/2 by PD098059 (ERK1/2 specific inhibitor) resulted in the suppression of EGF-induced COX-2 expression. The DNA binding activity of NF-kappaB was remarkably increased by EGF treatment and the pretreatment of PD098059 abolished EGF-stimulated NF-kappaB activity. We also observed that the level of PGE(2) was significantly elevated with the treatment of EGF in FLS, and the pretreatment of PD098059 abolished this stimulating effect. These results suggest that EGF is involved in the inflammatory process of RA by stimulating COX-2 expression and PGE(2) production. And EGF enhanced PGE(2) production appears to be mediated via ERK1/2 MAPK and NF-kappaB pathway in FLS.