BACKGROUND/OBJECTIVES: Obesity is a global health problem of significant importance which increases mortality. In place of anti-obesity drugs, natural products are being developed as alternative therapeutic materials. In this study, we investigated the effect of Brassica juncea L. leaf extract (BLE) on fat deposition and lipid profiles in high-fat, high-cholesterol diet (HFC)-induced obese rats. MATERIALS/METHODS: Male Sprague-Dawley rats were divided into four groups (n = 8 per group) according to diet: normal diet group (ND), high-fat/high-cholesterol diet group (HFC), HFC with 3% BLE diet group (HFC-A1), and HFC with 5% BLE diet group (HFC-A2). Each group was fed for 6 weeks. Rat body and adipose tissue weights, serum biochemical parameters, and tissue lipid contents were determined. The expression levels of mRNA and proteins involved in lipid and cholesterol metabolism were determined by reverse transcription polymerase chain reaction and western blot analysis, respectively. RESULTS: The HFC-A2 group showed significantly lower body weight gain and food efficiency ratio than the HFC group. BLE supplementation caused mesenteric, epididymal, and total adipose tissue weights to decrease. The serum levels of triglyceride, total cholesterol, and low-density lipoprotein cholesterol were significantly reduced, and high-density lipoprotein cholesterol was significantly increased in rats fed BLE. These results were related to lower glucose-6-phosphate dehydrogenase, acetyl-coA carboxylase, and fatty acid synthase mRNA expression, and to higher expression of the cholesterol 7α-hydroxylase and low density lipoprotein-receptor, as well as increased protein levels of peroxisome proliferator-activated receptor α. Histological analysis of the liver revealed decreased lipid droplets in HFC rats treated with BLE. CONCLUSIONS: Supplementation of HFC with 3% or 5% BLE inhibited body fat accumulation, improved lipid profiles, and modulated lipogenesis- and cholesterol metabolism-related gene and protein expression.
Acetyl-CoA Carboxylase ; Adipose Tissue ; Animals ; Anti-Obesity Agents ; Biological Products ; Blotting, Western ; Body Weight ; Brassica* ; Cholesterol ; Diet* ; Diet, High-Fat ; Global Health ; Glucosephosphate Dehydrogenase ; Humans ; Lipid Droplets ; Lipoproteins ; Liver ; Male ; Metabolism ; Mortality ; Mustard Plant* ; Obesity* ; Peroxisomes ; Polymerase Chain Reaction ; Rats* ; Rats, Sprague-Dawley ; Reverse Transcription ; RNA, Messenger ; Triglycerides ; Weights and Measures

BACKGROUND/OBJECTIVES: The study was conducted to evaluate the effects of dietary leucine supplementation on mitochondrial biogenesis and energy metabolism in the liver of normal birth weight (NBW) and intrauterine growth-retarded (IUGR) weanling piglets. MATERIALS/METHODS: A total of sixteen pairs of NBW and IUGR piglets from sixteen sows were selected according to their birth weight. At postnatal day 14, all piglets were weaned and fed either a control diet or a leucine-supplemented diet for 21 d. Thereafter, a 2 × 2 factorial experimental design was used. Each treatment consisted of eight replications with one piglet per replication. RESULTS: Compared with NBW piglets, IUGR piglets had a decreased (P < 0.05) hepatic adenosine triphosphate (ATP) content. Also, IUGR piglets exhibited reductions (P < 0.05) in the activities of hepatic mitochondrial pyruvate dehydrogenase (PDH), citrate synthase (CS), α-ketoglutarate dehydrogenase (α-KGDH), malate dehydrogenase (MDH), and complexes I and V, along with decreases (P < 0.05) in the concentration of mitochondrial DNA (mtDNA) and the protein expression of hepatic peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α). Dietary leucine supplementation increased (P < 0.05) the content of ATP, and the activities of CS, α-KGDH, MDH, and complex V in the liver of piglets. Furthermore, compared to those fed a control diet, piglets given a leucine-supplemented diet exhibited increases (P < 0.05) in the mtDNA content and in the mRNA expressions of sirtuin 1, PGC-1α, nuclear respiratory factor 1, mitochondrial transcription factor A, and ATP synthase, H+ transporting, mitochondrial F1 complex, β polypeptide in liver. CONCLUSIONS: Dietary leucine supplementation may exert beneficial effects on mitochondrial biogenesis and energy metabolism in NBW and IUGR weanling piglets.
Adenosine Triphosphate ; Birth Weight* ; Citrate (si)-Synthase ; Diet ; DNA, Mitochondrial ; Energy Metabolism* ; Fetal Growth Retardation ; Leucine* ; Liver ; Malate Dehydrogenase ; Nuclear Respiratory Factor 1 ; Organelle Biogenesis* ; Oxidoreductases ; Parturition* ; Peroxisomes ; Pyruvic Acid ; Research Design ; RNA, Messenger ; Sirtuin 1 ; Transcription Factors

We sought to identify common key regulators and build a gene-metabolite network in different nonalcoholic fatty liver disease (NAFLD) phenotypes. We used a high-fat diet (HFD), a methionine-choline-deficient diet (MCDD) and streptozocin (STZ) to establish nonalcoholic fatty liver (NAFL), nonalcoholic steatohepatitis (NASH) and NAFL+type 2 diabetes mellitus (T2DM) in rat models, respectively. Transcriptomics and metabolomics analyses were performed in rat livers and serum. A functional network-based regulation model was constructed using Cytoscape with information derived from transcriptomics and metabolomics. The results revealed that 96 genes, 17 liver metabolites and 4 serum metabolites consistently changed in different NAFLD phenotypes (>2-fold, P<0.05). Gene-metabolite network analysis identified ccl2 and jun as hubs with the largest connections to other genes, which were mainly involved in tumor necrosis factor, P53, nuclear factor-kappa B, chemokine, peroxisome proliferator activated receptor and Toll-like receptor signaling pathways. The specifically regulated genes and metabolites in different NAFLD phenotypes constructed their own networks, which were mainly involved in the lipid and fatty acid metabolism in HFD models, the inflammatory and immune response in MCDD models, and the AMPK signaling pathway and response to insulin in HFD+STZ models. Our study identified networks showing the general and specific characteristics in different NAFLD phenotypes, complementing the genetic and metabolic features in NAFLD with hepatic and extra-hepatic manifestations.
AMP-Activated Protein Kinases ; Animals ; Complement System Proteins ; Diabetes Mellitus ; Diet ; Diet, High-Fat ; Insulin ; Liver ; Metabolism ; Metabolomics ; Models, Animal ; Non-alcoholic Fatty Liver Disease* ; Peroxisomes ; Phenotype ; Rats ; Streptozocin ; Toll-Like Receptors ; Tumor Necrosis Factor-alpha

BACKGROUND: Non-alcoholic fatty liver disease is the most common form of chronic liver disease in industrialized countries. Recent studies have highlighted the association between peroxisomal dysfunction and hepatic steatosis. Peroxisomes are intracellular organelles that contribute to several crucial metabolic processes, such as facilitation of mitochondrial fatty acid oxidation (FAO) and removal of reactive oxygen species through catalase or plasmalogen synthesis. Statins are known to prevent hepatic steatosis and non-alcoholic steatohepatitis (NASH), but underlying mechanisms of this prevention are largely unknown. METHODS: Seven-week-old C57BL/6J mice were given normal chow or a methionine- and choline-deficient diet (MCDD) with or without various statins, fluvastatin, pravastatin, simvastatin, atorvastatin, and rosuvastatin (15 mg/kg/day), for 6 weeks. Histological lesions were analyzed by grading and staging systems of NASH. We also measured mitochondrial and peroxisomal FAO in the liver. RESULTS: Statin treatment prevented the development of MCDD-induced NASH. Both steatosis and inflammation or fibrosis grades were significantly improved by statins compared with MCDD-fed mice. Gene expression levels of peroxisomal proliferator-activated receptor α (PPARα) were decreased by MCDD and recovered by statin treatment. MCDD-induced suppression of mitochondrial and peroxisomal FAO was restored by statins. Each statin's effect on increasing FAO and improving NASH was independent on its effect of decreasing cholesterol levels. CONCLUSION: Statins prevented NASH and increased mitochondrial and peroxisomal FAO via induction of PPARα. The ability to increase hepatic FAO is likely the major determinant of NASH prevention by statins. Improvement of peroxisomal function by statins may contribute to the prevention of NASH.
Animals ; Atorvastatin Calcium ; Catalase ; Cholesterol ; Developed Countries ; Diet ; Fatty Liver* ; Fibrosis ; Gene Expression ; Hydroxymethylglutaryl-CoA Reductase Inhibitors* ; Inflammation ; Liver Diseases ; Liver* ; Metabolism ; Mice* ; Non-alcoholic Fatty Liver Disease ; Organelles ; Peroxisomes ; Pravastatin ; Reactive Oxygen Species ; Rosuvastatin Calcium ; Simvastatin

PURPOSE: The peroxisome proliferator-activated receptor gamma (PPARgamma) is a nuclear receptor that regulates expression of mediators of lipid metabolism and the inflammatory response. Thyroid hormone receptor-associated proteins 220 (TRAP220) is an essential component of the TRAP/Mediator complex. The objective of this study was to clarify whether PPARgamma or TRAP220 are significant prognostic markers in resectable colorectal cancer (CRC). MATERIALS AND METHODS: A total of 399 patients who underwent curative resection for CRC were enrolled. We investigated the presence of PPARgamma and TARP220 in CRC tissues and adjacent normal tissues by immunohistochemistry. Correlation between the expression of these factors and clinicopathologic features and survival was investigated. RESULTS: Median age of the patients was 63 years (range, 22 to 87 years), and median follow-up duration 61.1 months (range, 2 to 114 months). PPARgamma and TRAP220 expression showed significant correlation with depth of invasion (p=0.013 and p=0.001, respectively). Expression of TRAP220 also showed association with lymph node metastasis and TNM stage (p=0.001). Compared with patients with TRAP220 negative tumors, patients with TRAP220 positive tumors had longer 5-year disease-free survival (DFS) tendency (p=0.051). Patients who were PPARgamma positive combined with TRAP220 positive had a better 5-year DFS (64.8% vs. 79.3%, p=0.013). In multivariate analysis expression of both PPARgamma and TRAP220 significantly affected DFS (hazard ratio, 0.620; 95% confidence interval, 0.379 to 0.997; p=0.048). CONCLUSION: TRAP220 may be a valuable marker for nodal metastasis and TNM stage. Tumor co-expression of PPARgamma and TRAP220 represents a biomarker for good prognosis in CRC patients.
Colorectal Neoplasms* ; Disease-Free Survival ; Follow-Up Studies ; Humans ; Immunohistochemistry ; Lipid Metabolism ; Lymph Nodes ; Mediator Complex Subunit 1* ; Multivariate Analysis ; Neoplasm Metastasis ; Peroxisomes* ; PPAR gamma* ; Prognosis ; Thyroid Gland

Regulation of the peroxisome proliferator-activated receptor-γ (PPAR-γ) gene plays an important role in controlling the metabolism of lipids and inflammatory processes. Therefore, it can be associated with the pathogenesis of metabolic syndrome (MetS). The purpose of this study was to determine the expression of this gene in peripheral blood mononuclear cells (PBMC) in patients with metabolic syndrome. Using real-time polymerase chain reaction (PCR), mRNA expression of PPAR-γ was found in PBMC from 37 subjects with MetS and 30 healthy controls. Serum levels of glucose and lipid profiles were measured. The total antioxidant capacity (TAC) was measured using the ferric reducing ability of plasma (FRAP) test. Malondialdehyde (MDA) was determined using a fluorimetric method. Total oxidant status (TOS) in serum was assayed according to oxidation of ferric to ferrous in the presence of methyl orange. Super oxide dismutase (SOD) activity was measured using a Randox kit. Expression of PPAR-γ gene was significantly increased in patients with MetS compared to the control subjects (p=0.002). There was no difference in serum levels of TAC, MDA and SOD between the two study groups, but a significant difference was observed in the TOS (p=0.03). Serum levels of triglycerides and glucose were significantly higher in subjects with MetS. According to the results of our study, an increase in the expression of PPAR-γ in subjects with MetS indicated a possible role of PPAR-γ in the pathogenesis of this disease.
Citrus sinensis ; Gene Expression ; Glucose ; Humans ; Malondialdehyde ; Metabolism ; Methods ; Oxidative Stress ; Peroxisomes ; Plasma ; Real-Time Polymerase Chain Reaction ; RNA, Messenger ; Triglycerides

BACKGROUND: Peroxisome proliferator-activated receptor γ (PPARγ) plays a major role in adipocyte differentiation. Testosterone is well known for inhibiting adipocyte metabolism in men. To investigate the inhibitory mechanism of testosterone on adipogenesis, this study evaluated the effects of testosterone on PPARγ expression and activity in adipocytes using in vitro approaches. METHODS: After differentiated 3T3-L1 adipocytes were treated with PPARγ agonist troglitazone and sex hormone testosterone, the effects of testosterone on troglitazone-induced triglyceride accumulation and expression of genes involved in adipogenesis were investigated. We also investigated whether testosterone regulates troglitazone-induced PPARγreporter activity in 3T3-L1 preadipocytes. RESULTS: Testosterone decreased triglyceride accumulation in differentiated 3T3-L1 cells compared with the vehicle treated control group. Testosterone also decreased the expression of PPARγ mRNA as well as PPARγ dependent adipocyte-specific genes, such as adipocyte fatty acid binding protein and tumor necrosis factor α. Moreover, testosterone treatment inhibited triglyceride accumulation, and the expression of PPARγ and adipocyte-specific genes caused by troglitazone in differentiated 3T3-L1 cells. Testosterone decreased troglitazone-induced PPARγ reporter activity. Also, treatment with testosterone led to an inhibition of troglitazone-induced PPARγ reporter activity in PPARγ and androgen receptor (AR) expressed 3T3-L1 preadipocytes. CONCLUSION: These results suggest that testosterone interferes with the actions of PPARγ on adipogensis by an AR-dependent component. In addition, this study may have provided valuable molecular and biological insights regarding testosterone therapy in obese hypogonadal men.
3T3-L1 Cells ; Adipocytes ; Adipogenesis ; Carrier Proteins ; Humans ; In Vitro Techniques ; Male ; Metabolism ; Peroxisomes ; Receptors, Androgen ; RNA, Messenger ; Testosterone ; Triglycerides ; Tumor Necrosis Factor-alpha

BACKGROUND: Previous studies have shown that 17beta-estradiol activates AMP-activated protein kinase (AMPK) in rodent muscle and C2C12 myotubes and that acute 17beta-estradiol treatment rapidly increases AMPK phosphorylation possibly through non-genomic effects but does not stimulate glucose uptake. Here, we investigated whether 24-hour 17beta-estradiol treatment stimulated glucose uptake and regulated the expression of genes associated with glucose and energy metabolism through the genomic effects of estrogen receptor (ER) in C2C12 myotubes. METHODS: C2C12 myotubes were treated with 17beta-estradiol for 24 hours, and activation of AMPK, uptake of glucose, and expression of genes encoding peroxisome proliferator-activated receptor γ coactivator 1α, carnitine palmitoyltransferase 1β, uncoupling protein 2, and glucose transporter 4 were examined. Furthermore, we investigated whether AMPK inhibitor (compound C) or estrogen receptor antagonist (ICI182.780) treatment reversed 17beta-estradiol-induced changes. RESULTS: We found that 24-hour treatment of C2C12 myotubes with 17beta-estradiol stimulated AMPK activation and glucose uptake and regulated the expression of genes associated with glucose and energy metabolism. Treatment of C2C12 myotubes with the estrogen receptor antagonist (ICI182.780) reversed 17beta-estradiol-induced AMPK activation, glucose uptake, and changes in the expression of target genes. Furthermore, treatment with the AMPK inhibitor (compound C) reversed 17beta-estradiol-induced glucose uptake and changes in the expression of target genes. CONCLUSION: Our results suggest that 17beta-estradiol stimulates AMPK activation and glucose uptake and regulates the expression of genes associated with glucose and energy metabolism in C2C12 myotubes through the genomic effects of ER.
AMP-Activated Protein Kinases ; Carnitine O-Palmitoyltransferase ; Energy Metabolism ; Estrogens ; Glucose Transport Proteins, Facilitative ; Glucose ; Muscle Fibers, Skeletal ; Peroxisomes ; Phosphorylation ; Rodentia

BACKGROUND/AIMS: Both the farnesoid X receptor (FXR) and peroxisome proliferator-activated receptor (PPAR) play important roles in lipid metabolism and atherosclerosis. We investigated the interaction between FXR and PPARgamma. METHODS: Apolipoprotein E knockout (ApoE-/-) mice and FXR knockout (FXR-/-) mice were crossed to generate ApoE-/-FXR-/- mice. The mice were divided into ApoE-/-, ApoE-/-FXR-/-, and ApoE-/-FXR-/- + pioglitazone groups. All mice were fed a high-fat, high-cholesterol diet for 12 weeks. The ApoE-/-FXR-/- + pioglitazone group was also treated with pioglitazone, 20 mg/kg body weight. Body weight, blood glucose level, lipid profile, and liver enzyme levels were measured. To evaluate atherosclerotic lesions, the aorta was stained with Oil red O. RESULTS: There were no differences in body weight or blood glucose level among the three groups. The serum lipid concentration and liver enzyme levels increased in the ApoE-/-FXR-/- group compared with the ApoE-/- group (p < 0.01). The ApoE-/-FXR-/- + pioglitazone group had lower high-density lipoprotein (HDL) (55 +/- 4 vs. 28 +/- 2 mg/dL, p < 0.01) and low-density lipoprotein (LDL) (797 +/- 26 vs. 682 +/- 47 mg/dL, p = 0.04) cholesterol than the ApoE-/-FXR-/- group. The respective percentages of aortic atherosclerotic plaques in the ApoE-/-, ApoE-/-FXR-/-, and ApoE-/-FXR-/- + pioglitazone groups were 2.7 +/- 0.2%, 7.7 +/- 1.2%, and 18.6 +/- 1.0%. In ApoE-/-FXR-/- mice, the administration of pioglitazone significantly increased the number of atherosclerotic lesions (p = 0.02). CONCLUSIONS: Pioglitazone increased the number of atherosclerotic plaques in ApoE-/-FXR-/- mice. This suggests that when FXR is inhibited, the activation of PPARgamma can aggravate atherosclerosis.
Animals ; Aorta ; Apolipoproteins ; Atherosclerosis ; Blood Glucose ; Body Weight ; Cholesterol ; Diet ; Lipid Metabolism ; Lipoproteins ; Liver ; Mice ; Peroxisome Proliferator-Activated Receptors ; Peroxisomes ; Plaque, Atherosclerotic ; PPAR gamma ; Receptors, Cytoplasmic and Nuclear ; Thiazolidinediones

BACKGROUNDS/AIMS: During the acute phase response, cytokines induce marked alterations in lipid metabolism including an increase in serum triglyceride levels and a decrease in hepatic fatty acid oxidation, in bile acid synthesis, and in high-density lipoprotein levels. METHODS: Peroxisome proliferator-activated receptors (PPARs: PPARalpha, beta/delta, and gamma) regulate fatty acid metabolism, glucose homeostasis, cell proliferation, differentiation and inflammation. Proinflammatory profiles including tumor necrosis factor alpha (TNF-alpha), interleukin-1beta (IL-1beta), and interleukin-6 (IL-6) are the important pathological factors in inflammatory responses during the pathological progression of the acute phase response. Lipopolysaccarides (LPS) induced the expression of TNF-alpha, IL-1beta, and IL-6. LPS-induced inflammation decrease the expression of peroxisome proliferator-activated receptor alpha (PPARalpha), PPARbeta/delta, PPARgamma, and coactivators PPARgamma co-activator 1 alpha (PGC-1alpha), PGC-1beta messenger RNA (mRNA) in the liver of Balb/c mouse. In addition, LPS-induced inflammation diminishes the protein level of PPARalpha, PPARbeta/delta, and PPARgamma. Proinflammatory cytokines including TNFalpha, IL-1beta, and IL-6 are the principal reducer of PPARs. However, the knockout mouse model against TNFalpha and IL-6 does not block decrease of PPARs in serum and liver. The mice were pretreated with fenofibrate at 100 mg/kg for 2 days. RESULTS: These treatment protocols increased the amount of PPARs mRNA in the liver. Fenofibrate inhibited LPS-induced TNF-alpha, IL-1beta, and IL-6 production in the serum and liver. Similar results were obtained when human hepatoma HepG2 cells exposed to LPS were co-incubated with fenofibrate. LPS-treated HepG2 cells decreased expression of IkappaB. Moreover, activation of PPARs abrogated LPS-induced degradation of IkappaB, thus suppressing LPS-induced NF-kappaB activities. CONCLUSIONS: Therefore, fenofibrate decreases the expression and secretion of TNF-alpha, IL-1beta, and IL-6 via the NF-kappaB signaling pathway, thus serving as therapeutic targets to attenuate inflammation that is involved in hepatic pathological progression.
Animals ; Bile ; Carcinoma, Hepatocellular ; Cell Proliferation ; Clinical Protocols ; Cytokines ; Fenofibrate ; Glucose ; Hep G2 Cells ; Homeostasis ; Humans ; Inflammation ; Interleukin-1beta ; Interleukin-6 ; Lipid Metabolism ; Lipoproteins ; Liver ; Mice ; Mice, Knockout ; NF-kappa B ; Peroxisome Proliferator-Activated Receptors ; Peroxisomes ; PPAR alpha ; PPAR-beta ; PPAR delta ; PPAR gamma ; RNA, Messenger ; Tumor Necrosis Factor-alpha