Expression Of Carnitine Palmitoyltransferase Research Articles

Influences of sterol regulatory element binding protein-1c silencing on glucose production in HepG2 cells treated with free fatty acid

BackgroundElevation of exogenous free fatty acid (FFA) level leads to insulin resistance (IR) in liver, IR is manifested by elevated hepatic glucose production. We aim to study whether inhibition of endogenous fatty acid synthesis could decrease hepatic glucose production.MethodsLow-passage HepG2 cells derived from human liver tissue were cultured in medium supplemented with FFA to induce IR, the influences of sterol regulatory element binding protein-1c (SREBP-1c) silencing on glucose production of HepG2 cells were investigated, and genes responsible for fatty acid and glucose metabolism were detected by real-time PCR.ResultsCompared with HepG2 cells cultured in normal growth medium, glucose production of HepG2 cells treated by FFA was significantly increased {[(0.28 ± 0.01) vs (0.83 ± 0.02)] umol.ug− 1 protein, n = 6 wells, P < 0.01}; the mRNA expression of phosphoenolpyruvate carboxylase kinase (PEPCK) and glucose-6-phosphatase (G6PC) in HepG2 cells increased by more than 5-fold and 3-fold, respectively; the mRNA expression of fatty acid synthase (FAS) and stearoyl-CoA desaturase-1 (SCD1) increased by approximately 4-fold and 1.1-fold, respectively; the mRNA expression of carnitine palmitoyltransferase-1 (CPT-1) changed slightly. Compared with the scrambled siRNA control, glucose production of HepG2 cells treated by FFA significantly increased after SREBP-1c silencing {[(0.018 ± 0.001) vs (0.028 ± 0.002)] umol.ug− 1 protein, n = 6 wells, P < 0.01}; the mRNA expression of PEPCK and G6PC increased by approximately 1.5-fold and 5-fold, respectively, but the mRNA expression of FAS, SCD1 and CPT-1 changed slightly.ConclusionsSREBP-1c silencing further augmented glucose production of HepG2 cells treated by FFA significantly, genes responsible for fatty acid synthesis and gluconeogenesis played an important role in this process. SREBP-1c functions not only as a lipid regulator but also plays an important role in regulation of glucose metabolism.

Western diet consumption through early life induces microvesicular hepatic steatosis in association with an altered metabolome in low birth weight Guinea pigs

Uteroplacental insufficiency-induced low birth weight (LBW) and postnatal high saturated fat/high sucrose-fructose diet (Western Diet, WD) consumption have been independently associated with the development of hepatic steatosis, while their additive effect on fatty acid, acylcarnitine and amino acid profiles in early adulthood have not been widely reported. We employed LBW, generated via uterine artery ablation, and normal birth weight (NBW) male guinea pigs fed either a WD or control diet (CD) from weaning to postnatal day 150 (early adulthood). Hepatic steatosis was absent in CD-fed offspring, while NBW/WD offspring displayed macrovesicular steatosis and LBW/WD offspring exhibited microvesicular steatosis, both occurring in a lean phenotype. Life-long consumption of the WD, irrespective of birth weight, was associated with an increase in hepatic medium- and long-chain saturated fatty acids, monounsaturated fatty acids, acylcarnitines, reduced oxidative phosphorylation complex III activity and polyunsaturated fatty acids, and molecular evidence of disrupted hepatic insulin signaling. In NBW/WD, hepatic C15:1 and C16:1n-6 fatty acids in phospholipids, C16, C18 and C18:1 acylcarnitines, concentrations of aspartate, phenylalanine, tyrosine and tryptophan and expression of carnitine palmitoyltransferase 1 alpha (CPT1α) and uncoupling protein 2 (UCP2) genes were elevated compared to LBW/WD livers. Our results suggest that LBW and life-long WD combined are influential in promoting hepatic microvesicular steatosis in conjunction with a specific mitochondrial gene expression and metabolomic profile in early adulthood.

Rare ginsenosides ameliorate lipid overload-induced myocardial insulin resistance via modulating metabolic flexibility

BackgroundRare ginsenosides are found in ginseng and notoginseng, two medicinal plants widely used in China for treatment of cardiovascular diseases and type 2 diabetes. However, their pharmacological studies regarding myocardial fuel metabolism and insulin signaling are not clear. PurposeTo explore the effect of a rare ginsenoside-standardized extract (RGSE), derived from steamed notoginseng, on cardiac fuel metabolism and insulin signaling. Study designWe used palmitic acid (PA) to treat H9c2 cells in vitro and high fat diet (HFD) to mice to induce insulin resistance in vivo. MethodsIn vitro, differentiated H9c2 cells were pretreated with RGSE, metformin, mildronate or dichloroacetate (DCA) and stimulated with PA. In vivo, mice were fed with HFD and received RGSE, metformin or DCA for 6 weeks. Protein expression was determined by Western blotting. Mitochondrial membrane potential (Δψm), glucose uptake and reactive oxygen species (ROS) production were measured by fluorescence labeling. Other assessments including oxygen consumption rate (OCR) were also performed. ResultsRGSE prevented PA-induced decrease in pyruvate dehydrogenase (PDH) activity and increase in carnitine palmitoyltransferase 1 (CPT1) expression, and ameliorated insulin-mediated glucose uptake and utilization in H9c2 cells. Metformin and mildronate exhibited similar effects. In vivo, RGSE counteracted HFD-induced increase in myocardial expression of p-PDH and CPT1 and ameliorated cardiac insulin signaling. Metformin and DCA also showed beneficial effects. Further study showed that RGSE decreased OCR and mitochondrial complex I activity in PA-treated H9c2 cells, reduced ROS production and relieved mitochondrial oxidative stress, thus decreased serine phosphorylation in IRS-1. ConclusionRGSE ameliorated myocardial insulin sensitivity under conditions of lipid overload, which was tightly associated with the decrease in mitochondrial oxidative stress via modulating glucose and fatty acid oxidation.

Rosiglitazone ameliorates palmitic acid-induced cytotoxicity in TM4 Sertoli cells

The Sertoli cell is the only somatic cell within the seminiferous tubules, and is vital for testis development and spermatogenesis. Rosiglitazone (RSG) is a member of the thiazolidinedione family and is a peroxisome proliferator-activated receptor-γ (PPARγ) agonist. It has been reported that RSG protects various types of cells from fatty acid-induced damage. However, whether RSG serves a protective role in Sertoli cells against palmitic acid (PA)-induced toxicity remains to be elucidated. Therefore, the aim of the present study was to investigate the effect of RSG on PA-induced cytotoxicity in Sertoli cells. MTT assay and Oil Red O staining revealed that RSG ameliorated the PA-induced decrease in TM4 cell viability, which was accompanied by an alleviation of PA-induced lipid accumulation in cells. In primary mouse Sertoli cells, RSG also showed similar protective effects against PA-induced lipotoxicity. Knockdown of PPARγ verified that RSG exerted its protective role in TM4 cells through a PPARγ-dependent pathway. To evaluate the mechanism underlying the protective role of RSG on PA-induced lipotoxicity, the present study analyzed the effects of RSG on PA uptake, and the expression of genes associated with both fatty acid oxidation and triglyceride synthesis. The results demonstrated that although RSG did not affect the endocytosis of PA, it significantly elevated the expression of carnitine palmitoyltransferase (CPT)-1A, a key enzyme involved in fatty acid oxidation, which indicated that the protective effect of RSG may have an important role in fatty acid oxidation. On the other hand, the expression of CPT1B was not affected by RSG. Moreover, the expression levels of diacylglycerol O-acyltransferase (DGAT)-1 and DGAT2, both of which encode enzymes catalyzing the synthesis of triglycerides, were not suppressed by RSG. The results indicated that RSG reduced PA-induced lipid accumulation by promoting fatty acid oxidation mediated by CPT1A. The effect of RSG in protecting cells from lipotoxicity was also found to be specific to Sertoli cells and hepatocytes, and not to other cell types that do not store excess lipid in large quantities, such as human umbilical vein endothelial cells. These findings provide insights into the cytoprotective effects of RSG on Sertoli cells and suggest that PPARγ activation may be a useful therapeutic method for the treatment of Sertoli cell dysfunction caused by dyslipidemia.

Ameliorating effects of Sporidiobolus pararoseus extract on dyslipidemia in mice with high fat diet induced obesity.

The study investigated how an extract of Sporidiobolus pararoseus (S.p.) affects lipid metabolism in Kunming mice that were obese as a result of being fed a high-fat diet; the control group were administered Max EPA fish oil. Ten mice were randomly selected from a pool of 60 mice for the control group and the remaining 50 mice were fed with a high-fat diet to establish a dyslipidemia model. After 4 weeks, these 50 mice were randomly distributed among 5 groups: high-fat model group; Max EPA group; and 3 groups of mice fed different doses of S.p. extract (low dose, medium dose, and high dose). After 8 weeks, the mice were sacrificed and the relevant parameters were measured. Compared with the high-fat model group, the group administered the high dose of S.p. extract showed significantly decreased body mass and serum levels of total cholesterol, triglycerides, and low-density lipoprotein cholesterol, and increased levels of high-density lipoprotein cholesterol. The results from RT-PCR showed that the mRNA expression of sterol regulatory element-binding protein 1c, fatty acid synthesis enzyme, and acetyl-CoA carboxylase was lower in the groups supplemented with S.p. extract than in the high-fat model group, whereas the expression of carnitine palmitoyltransferase 1 was higher in the group supplemented with S.p. extract than in the high-fat model group. Our results suggest that taking S.p. extract could benefit patients with dyslipidemia. Therefore, S.p. extract should be developed as a dietary supplement to improve lipid metabolism in obese people.

Pharmacological Action of a Pregnane Glycoside, Russelioside B, in Dietary Obese Rats: Impact on Weight Gain and Energy Expenditure.

Background and purpose: Russelioside B (RB) is a pregnane glycoside obtained from Caralluma quadrangula; a herb with antidiabetic, anti-inflammatory, and antihyperlipidemic activities. The present experiment tested the possible role of RB in controlling weight gain in rats fed on high fat (HF) diet.Methods: RB was separated from the n-butanol fraction of the crude methanolic extract by chromatographic separation on a Si gel column according to the procedures described previously. The experiment of the biological assessment of RB used 32 male Wistar rats (4 groups, n = 8). Group 1 rats were fed with a palatable normal diet. Group 2, 3, and 4 were fed on HF diet for 16 weeks. Group 2 served as the HF diet control group while Group 3 and 4 received daily oral doses of RB (25 and 50 mg/kg) during the last four weeks. Animals’ parameters like weight gain, fasting level of blood sugar, serum lipids, and serum liver enzyme activities were measured. Liver or adipose tissue weight was divided by the rat’s body weight and multiplied by 100 to obtain the liver or adipose tissue index, respectively. Adipose tissues were processed for histopathological examination, measurement of mRNA expression of visfatin, leptin, adiponectin, uncoupling protein-1 (UCP-1), and carnitine palmitoyl transferase-1 (CPT-1). Furthermore, serum levels of insulin, interleukin-6 (IL-6), IL-1β, tumor necrosis factor-α (TNF-α), leptin, resistin, and adiponectin were assessed using ELISA kits.Results: Rats fed with the HF diet exhibited significant body weight gain, abnormal liver function, disturbed lipid profile, and greater serum level of pro-inflammatory cytokines in addition to greater insulin resistance, adipose tissue and liver indices. Further, rats fed with the HF diet displayed upregulations in the expression of visfatin and leptin with downregulations in the expression of adiponectin, UCP-1, and CPT-1 compared to normal rats. Interestingly, RB (25 or 50 mg/kg) favorably modulated the measured parameters.Conclusion: Data from this study documented the beneficial role of RB in diminishing weight gain, improving the inflammatory perturbations and energy expenditure in HF diet fed rats. Therefore, RB might be a promising candidate for obesity.

AMPK activation by pterostilbene contributes to suppression of hepatic gluconeogenic gene expression and glucose production in H4IIE cells

Pterostilbene, a bioactive component of blueberries and grapes, shows structural similarity to resveratrol, and exhibits antioxidant, anti-inflammatory, anti-cancer, hypoglycemic, and cholesterol lowering effects. Recent evidence indicates that pterostilbene is an agonist of the nuclear receptor, peroxisome proliferator-activated receptor-alpha (PPAR-α). Since PPAR-α agonists induce peroxisomal proliferation and fatty acid oxidation, we examined gene expression of acyl CoA oxidase (ACO) and carnitine palmitoyl transferase-1 (CPT-1). Pterostilbene treatment, at concentrations that demonstrated over 75% cell viability (20 μM, 50 μM), significantly increased gene expression of ACO, CPT-1, and PPAR-α. Pterostilbene treatment (50 μM) also demonstrated potent activation of AMP-activated kinase (AMPK), compared to AICAR (0.5 mM) or metformin (2 mM), consistent with upregulation in fatty acid oxidation gene expression. Since AMPK activators mimic the actions of insulin by repressing hepatic gluconeogenesis, we examined pterostilbene's effects on hepatic gluconeogenic gene expression. Pterostilbene treatment significantly repressed dexamethasone-induced phosphoenol pyruvate carboxykinase (PEPCK) and glucose6-phosphatase (G6Pase) gene expression, and decreased glucose production in H4IIE cells. Taken together, our studies demonstrate that pterostilbene, a natural compound and PPAR-α agonist, modulate several AMPK-dependent metabolic functions. The results of the present study suggest that pterostilbene may have beneficial effects in the prevention and management of type 2 diabetes and related disorders. In this study, we found that pterostilbene activated AMP-activated kinase (AMPK) and increased the expression of fatty acid oxidation genes, including acyl CoA oxidase and carnitine palmitoyl transferase-1.

Dietary α-lactalbumin induced fatty liver by enhancing nuclear liver X receptor αβ/sterol regulatory element-binding protein-1c/PPARγ expression and minimising PPARα/carnitine palmitoyltransferase-1 expression and AMP-activated protein kinase α phosphorylation associated with atherogenic dyslipidaemia, insulin resistance and oxidative stress in Balb/c mice.

The effect and the role played by dietary α-lactalbumin (α-LAC) on hepatic fat metabolism are yet to be fully elucidated. We reported previously that α-LAC intake induced atherogenic dyslipidaemia in Balb/c mice. The aim of the present study was to investigate if this atherogenic effect could be due to a possible α-LAC-induced hepatic steatosis. We examine the ability of dietary α-LAC to induce liver steatosis, identifying the molecular mechanisms underlying hepatic lipid metabolism in association with the lipid profile, peripheral insulin resistance (IR) and changes in the hepatic oxidative environment. Male Balb/c mice (n 6) were fed with diets containing either chow or 14 % α-LAC for 4 weeks. The α-LAC-fed mice developed abdominal adiposity and IR. Moderate liver steatosis with increased TAG and NEFA contents was correlated with atherogenic dyslipidaemia. There was increased nuclear expression of liver X receptor αβ (LXRαβ), sterol regulatory element-binding protein-1c (SREBP-1c) and PPARγ transcription factors and of the cytosolic enzymes acetyl-CoA carboxylase 1 (ACC1) and fatty acid synthase involved in the hepatic de novo lipogenesis. The opposite was found for the nuclear receptor PPARα and the mitochondrial enzyme carnitine palmitoyltransferase-1 (CPT-1), leading to reduced fatty acid β-oxidation (FAO). These changes were associated with a significant decrease in both p-Thr172-AMP-activated protein kinase α (AMPKα) (inactivation) and p-Ser79-ACC1 (activation) and with a more oxidative liver environment increasing lipid peroxidation and protein oxidation and reducing GSH:GSSG ratio in the α-LAC-fed mice. In conclusion, 4 weeks of 14 % α-LAC feeding induced liver steatosis associated with atherogenic dyslipidaemia, IR and oxidative stress by enhancing nuclear LXRαβ/SREBP-1c/PPARγ expression and diminishing PPARα/CPT-1 expression and AMPKα phosphorylation shifting the hepatic FAO toward fatty acid synthesis in Balb/c mice.

Partitioning of adipose lipid metabolism by altered expression and function of PPAR isoforms after bariatric surgery.

BackgroundBariatric surgery remains the most effective treatment for reducing adiposity and eliminating type 2 diabetes, however the mechanism(s) responsible have remained elusive. Peroxisome proliferator activated receptors (PPAR) encompass a family of nuclear hormone receptors that upon activation exert control of lipid metabolism, glucose regulation, and inflammation. Their role in adipose tissue following bariatric surgery remains undefined.Materials and MethodsSubcutaneous adipose tissue biopsies and serum were obtained and evaluated from at time of surgery and on postoperative day 7 in patients randomized to Roux-en-Y gastric bypass (n=13) or matched caloric restriction (n=14), as well as patients undergoing vertical sleeve gastrectomy (n=33). Fat samples were evaluated for changes in gene expression, protein levels, β-oxidation, lipolysis, and cysteine oxidation.ResultsWithin 7 days, bariatric surgery acutely drives a change in the activity and expression of PPARγ and PPARδ in subcutaneous adipose tissue thereby attenuating lipid storage, increasing lipolysis and potentiating lipid oxidation. This unique metabolic alteration leads to changes in downstream PPARγ/δ targets including decreased expression of FABP4 and SCD1 with increased expression of carnitine palmitoyl transferase 1 (CPT1) and uncoupling protein 2 (UCP2). Increased expression of UCP2 not only facilitated fatty acid oxidation (increased 15-fold following surgery) but also regulated the subcutaneous adipose tissue redoxome by attenuating protein cysteine oxidation and reducing oxidative stress. The expression of UCP1, a mitochondrial protein responsible for the regulation of fatty acid oxidation and thermogenesis in beige and brown fat, was unaltered following surgery.ConclusionsThese results suggest that bariatric surgery initiates a novel metabolic shift in subcutaneous adipose tissue to oxidize fatty acids independently from the beiging process through regulation of PPAR isoforms. Further studies are required to understand the contribution of this shift in expression of PPAR isoforms as a contributor to weight loss following bariatric surgery.

The Effect of Sitagliptin on Lipid Metabolism of Fatty Liver Mice and Related Mechanisms.

BackgroundIn clinics, patients with type 2 diabetes complicated with non-alcoholic fatty liver disease (NAFLD) have been shown to receive significant improvements in blood glucose levels, lipid levels, and liver function after sitagliptin treatment, although the mechanism of drug action remains poorly understood. This study investigated the possible mechanism of sitagliptin on lipid metabolism of NAFLD mice.Material/MethodsMale C57/BL6 mice were induced for NAFLD via 16 weeks of a high-fat diet, and were treated with 15 mg/kg/day sitagliptin for 16 consecutive weeks. Blood lipid levels were measured and samples were stained with hematoxylin and eosin (H&E) and oil red staining for liver pathology and lipid deposition. Serum levels of fibroblast growth factor (FGF)-9 and FGF-21 were quantified by enzyme-linked immunosorbent assay (ELISA). Peroxisome proliferator-activated receptor (PPAR)-α, and cAMP reactive element binding homolog (CREBH) were measured by Western blotting, while fatty acid synthase and carnitine palmitoyltransferase 1 (CPT1) mRNA levels were assayed by RT-PCR.ResultsCompared to the control group, the NAFLD model mice had liver fatty disease, lower serum FGF-21 and FGF-19 levels, elevated serum lipid levels, depressed PPAR-α, CREBH, and CPT1 expression, and enhanced FAS expression (p<0.05). Sitagliptin treatment depressed blood lipid levels, increased serum FGF-21 and FGF-19 levels, PPAR-α, CREBH, and CPT1 expression, and suppressed FAS expression (p<0.05).ConclusionsSitagliptin can protect liver tissue and modulate lipid metabolism in NAFLD mice via elevating FGF-21 and FGF-19, upregulating liver PPAR-α and CREBH levels, and mediating expression levels of key enzymes for lipid metabolism.

Systemic regulation of L-carnitine in nutritional metabolism in zebrafish, Danio rerio

Excess fat accumulation has been observed widely in farmed fish; therefore, efficient lipid-lowering factors have obtained high attention in the current fish nutrition studies. Dietary L-carnitine can increase fatty acid β-oxidation in mammals, but has produced contradictory results in different fish species. To date, the mechanisms of metabolic regulation of L-carnitine in fish have not been fully determined. The present study used zebrafish to investigate the systemic regulation of nutrient metabolism by dietary L-carnitine supplementation. L-carnitine significantly decreased the lipid content in liver and muscle, accompanied by increased concentrations of total and free carnitine in tissues. Meanwhile, L-carnitine enhanced mitochondrial β-oxidation activities and the expression of carnitine palmitoyltransferase 1 mRNA significantly, whereas it depressed the mRNA expression of adipogenesis-related genes. In addition, L-carnitine caused higher glycogen deposition in the fasting state, and increased and decreased the mRNA expressions of gluconeogenesis-related and glycolysis-related genes, respectively. L-carnitine also increased the hepatic expression of mTOR in the feeding state. Taken together, dietary L-carnitine supplementation decreased lipid deposition by increasing mitochondrial fatty acid β-oxidation, and is likely to promote protein synthesis. However, the L-carnitine-enhanced lipid catabolism would cause a decrease in glucose utilization. Therefore, L-carnitine has comprehensive effects on nutrient metabolism in fish.

Hepatic expression of FTO and fatty acid metabolic genes changes in response to lipopolysaccharide with alterations in m6A modification of relevant mRNAs in the chicken

The fat mass and obesity associated (FTO) gene, which encodes a demethylase of m6A, has been reported to respond to lipopolysaccharide (LPS) and to serve as a link between inflammation and metabolic responses. The objective of this study was to determine whether LPS-induced changes in the expression of FTO and metabolic genes are associated with alterations of m6A in relevant mRNAs.LPS challenge significantly decreased hepatic mRNA expression of carnitine palmitoyl transferase 1 (CPT1) and CPT2, which coincided with a tendency of higher triglyceride accumulation in the liver.LPS significantly down-regulated the full length cFTO1, yet up-regulated the truncated cFTO4 protein in the liver nuclear extracts.Nuclear protein content of cFTO4 in the liver was negatively correlated with the mRNA abundances of CPT1 (r = 0.629) and CPT2 (r = 0.622).Methylated RNA immunoprecipitation analysis revealed that the m6A level around the translation start site of CPT1 was markably decreased in the liver of LPS-treated chickens.These results indicate that LPS-induced changes in FTO protein expression are associated with alteration of mRNA m6A modification in chicken liver.

Integrated Regulation of Hepatic Lipid and Glucose Metabolism by Adipose Triacylglycerol Lipase and FoxO Proteins.

Metabolism is a highly integrated process that is coordinately regulated between tissues and within individual cells. FoxO proteins are major targets of insulin action and contribute to the regulation of gluconeogenesis, glycolysis, and lipogenesis in the liver. However, the mechanisms by which FoxO proteins exert these diverse effects in an integrated fashion remain poorly understood. We report that FoxO proteins also exert important effects on intrahepatic lipolysis and fatty acid oxidation via the regulation of adipose triacylglycerol lipase (ATGL), which mediates the first step in lipolysis, and its inhibitor, the G0/S1 switch 2 gene (G0S2). We also find that ATGL-dependent lipolysis plays a critical role in mediating diverse effects of FoxO proteins in the liver, including effects on gluconeogenic, glycolytic, and lipogenic gene expression and metabolism. These results indicate that intrahepatic lipolysis plays a critical role in mediating and integrating the regulation of glucose and lipid metabolism downstream of FoxO proteins.

Expression of lipid metabolism-related proteins in breast phyllodes tumors.

The aim of this study was to investigate the expression of lipid metabolism-related proteins and the implications thereof in phyllodes tumor (PT) of the breast. Atissue microarray (TMA) was constructed using paraffin blocks from 194 PT patient tissue samples. Immunohistochemical staining for lipid metabolism-related proteins, namely hormone-sensitive lipase (HSL), perilipin 2, fatty-acid-binding proteins 4 (FABP4), carnitine palmitoyltransferase-1 (CPT-1), acyl-CoA oxidase 1 (ACOX-1), and fatty acid synthase (FASN) was performed, and the immunohistochemical staining results were analyzed with respect to clinicopathologic parameters. The numbers of benign, borderline, and malignant PTs were 151, 27, and 16, respectively. The expression of HSL, perilipin 2, FABP4, CPT-1, and FASN in stromal components was higher in higher grade tumors. On univariate analysis, shorter disease-free survival (DFS) was associated with stromal perilipin 2 positivity (p<0.001) and stromal CPT-1 positivity (p=0.004). Shorter overall survival (OS) was associated with stromal perilipin 2 positivity (p<0.001), stromal FABP4 positivity (p<0.001), stromal CPT-1 positivity (p=0.004), and stromal FASN positivity (p<0.001). Multivariate Cox analysis revealed that stromal perilipin 2 positivity (hazard ratio=31.693, 95% CI: 1.341-748.8, p=0.032) was an independent factor for shorter DFS. In conclusion, higher expressions of HSL, perilipin 2, FABP4, CPT-1 and FASN in the stromal component were observed in higher grade PT.

Fish oil diet in pregnancy and lactation reduces pup weight and modifies newborn hepatic metabolic adaptations in rats.

To determine the effects of a diet containing fish oil (FD) during pregnancy and lactation in rats on the metabolic adaptations made by the offspring during early extrauterine life and to compare it to an olive oil diet (OD). Rats were mated and randomly allocated to OD or FD containing 10% of the corresponding oil. During lactation, litters were adjusted to eight pups per dam. Fetuses of 20days and pups of 0, 1, 10, 20 and 30days of age were studied. Body weight and length were lower in pups of the FD group from birth. The diet, milk, pups' plasma and liver of FD group had higher proportions of n-3 LCPUFA, but the content of arachidonic acid (ARA) was lower. Plasma glucose was higher, but unesterified fatty acids, triacylglycerols (TAG), 3-hydroxybutyrate and liver TAG in 1-day-old pups were lower in the FD group, and differences in some of these variables were also found in pups up to 30days old. Liver lipoprotein lipase activity and mRNA expression, and the expression of carnitine palmitoyl transferase I, acyl-CoA oxidase and 3-hydroxy 3-methyl glutaryl-CoA synthase increased more at birth in pups of the FD group, but the expression of sterol regulatory element binding protein-1c and Δ6-desaturase mRNA was lower in the FD group. Maternal intake of high n-3 LCPUFA retards postnatal development, which could be the result of impaired ARA synthesis, and affects hepatic metabolic adaptations to extrauterine life.

라이코펜 첨가 급여가 닭의 지방대사, 포도당 수송 및 친염증 유전자 발현에 미치는 영향

Dept. of Animal Science and Biotechnology, Gyeongnam National University of Science and Technology, Jinju 52725, KoreaABSTRACT The present study aimed to investigate the effects of lycopene on hepatic metabolic- and immune-related gene expression in laying hens. A total of 48 25-week-old White Leghorn hens were randomly allocated into four groups consisting of four replicates of three birds: control (basal diet), T1 (basal diet + 10 mg/kg of tomato powder-containing lycopene), T2 (basal diet + 10 mg/kg of micelles of tomato powder-containing lycopene), and T3 (basal diet + 10 mg/kg of purified lycopene). Chickens were fed ad libitum for 5 weeks, and then total RNA was extracted from the livers for quantitative RT-PCR analysis. Peroxisome proliferator-activated receptor ɣ (PPARɣ) expression was decreased in the liver of chickens after lycopene supplementation (P<0.05). Micellar lycopene supplementation decreased the expression of PPARɣ target genes including fatty acid binding protein 4 (FABP4) and fatty acids synthase (FASN) in the T2 group (P<0.05). Sterol regulatory element-binding protein 2 (SREBP2) and C/EBP-ɑ were also downregulated in hens fed with micellar lycopene (P<0.05). Glucose transporter 8 (GLUT-8) was upregulated in the T2 and T3 groups (P<0.05). However, the expression of carnitine palmitoyltransferase 1 (CPT-1) was not changed by lycopene supplementation. Pro-inflammatory cytokines such as tumor necrosis factor ɑ (TNF-ɑ) and interleukin 6 (IL-6) were downregulated by lycopene supplementation (P<0.05). These data suggest that the type of lycopene supplementation is critical and that micelles of tomato powder-containing lycopene may play an important role in the modulation of lipid metabolism and immunity in chickens.(Key words: lycopene, gene expressions, metabolism, inflammation, chickens)

FSH and bFGF regulate the expression of genes involved in Sertoli cell energetic metabolism

The purpose of this study was to investigate if FSH and bFGF regulate fatty acid (FA) metabolism and mitochondrial biogenesis in Sertoli cells (SC). SC cultures obtained from 20-day-old rats were incubated with 100ng/ml FSH or 30ng/ml bFGF for 6, 12, 24 and 48h. The expression of genes involved in transport and metabolism of FA such as: fatty acid transporter CD36 (FAT/CD36), carnitine-palmitoyltransferase 1 (CPT1), long- and medium-chain 3-hydroxyacyl-CoA dehydrogenases (LCAD, MCAD), and of genes involved in mitochondrial biogenesis such as: nuclear respiratory factors 1 and 2 (NRF1, NRF2) and transcription factor A (Tfam), was analyzed. FSH stimulated FAT/CD36, CPT1, MCAD, NRF1, NRF2 and Tfam mRNA levels while bFGF only stimulated CPT1 expression. A possible participation of PPARβ/δ activation in the regulation of gene expression and lactate production was then evaluated. SC cultures were incubated with FSH or bFGF in the presence of the PPARβ/δ antagonist GSK3787 (GSK; 20μM). bFGF stimulation of CPT1 expression and lactate production were inhibited by GSK. On the other hand, FSH effects were not inhibited by GSK indicating that FSH regulates the expression of genes involved in FA transport and metabolism and in mitochondrial biogenesis, independently of PPARβ/δ activation. FA oxidation and mitochondrial biogenesis as well as lactate production are essential for the energetic metabolism of the seminiferous tubule. The fact that these processes are regulated by hormones in a different way reflects the multifarious regulation of molecular mechanisms involved in Sertoli cell function.

Overnourishment during lactation induces metabolic and haemodynamic heart impairment during adulthood

AimIn this study, the effects of postnatal overfeeding on heart energy homoeostasis and cardiac haemodynamics in adult male Swiss mice were examined. Methods and ResultsDuring the suckling period, the mice were divided into four groups of control or overfed pups in combination with baseline or ischaemia/reperfusion treatments (control group baseline, CGBL; overfed group baseline, OGBL; control group ischaemia/reperfusion, CGIR; and overfed group ischaemia/reperfusion, OGIR). End diastolic pressure (EDP), heart contraction speed (Max dP/dt), relaxation speed (Min dP/dt), isovolumetric relaxation time (Tau) and frequency by beats per minute (BPM) were measured. During baseline and ischaemia/reperfusion, key proteins such as AKT1, AKT2, AKT3, pAKT, adenosine monophosphate-activated protein kinase (AMPK), pAMPK, insulin receptor beta (IRβ), protein tyrosine phosphatase 1B (PTP1B), insulin receptor substrate 1 (IRS1), fatty acid binding protein (FABP), CD36, phosphoinositide 3-kinase (PI3K) and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) were studied. The expression of atrial natriuretic peptide (ANP), B-type natriuretic peptide (BNP), carnitine palmitoyltransferase 1 (CPT1) and uncoupling protein 3 (UCP3) was studied as a marker of cardiac hypertrophy and energetic metabolism. Cardiac fibrosis was analyzed by quantifying collagen deposition, which is increased in the OGBL and OGIR groups compared with the control groups. ConclusionsThe OGBL group showed reduced EDP compared with the CGBL group and high Max dP/dt compared with the OGBL group. Ischaemia/reperfusion increased EDP and Min dP/dt in the intragroup comparison. By contrast, Tau and frequency were not significantly different among groups. The OGIR mice showed significant alterations in heart metabolism proteins, including AKT2, pAKT/AKT1, pAKT/AKT2, AMPK, pAMPK/AMPK, PTP1B, IRS1, FABP and CD36. Furthermore, alterations in ANP, BNP, CPT1 and UCP3 messenger RNA (mRNA) expression indicated hypertrophy and reduction in their efficiency, such that exclusive overnutrition in childhood induces a long-term effect on haemodynamics, metabolism and heart remodelling.

Morphology, mitochondrial development and adipogenic-related genes expression during adipocytes differentiation in grass carp (Ctenopharyngodon idellus)

To investigate the differentiation mechanism of grass carp preadipocytes, a primary adipocytes culture system was established. Confluent preadipocytes were induced to differentiation, and the morphology and gene expression were evaluated at different stages. It was shown that preadipocytes were gradually filled with droplets and the cellular lipid content increased during the differentiation. Ultrastructure observation indicated that the number of mitochondria increased with adipocytes differentiation. Consistently, the mitochondrial protein content was elevated in the differentiating adipocytes. qRT-PCR showed that the expression level of lipogenesis-related genes such as peroxisome proliferator activator receptor γ (PPAR γ), lipoprotein lipase (LPL), fatty acid synthase (FAS) and stearoyl-CoA desaturase (SCD) increased during adipocytes differentiation. The mitochondrial relevant gene also elevated when adipocyte differentiation, such as PPAR coactivator-1 (PGC-1 α), PGC-1 β and nuclear respiratory factor (NRF-1). However, the expression of carnitine palmitoyltransferase I α (CPT-1 α) gene decreased at the initial stage, but increased at the last stage of cell differentiation. These results indicated that the differentiation process of grass carp preadipocytes is similar to that of land animals, but the molecular mechanisms are not exactly the same. The findings revealed in this study provides new information to the study of fish adipocyte differentiation.

Apolipoprotein D Transgenic Mice Develop Hepatic Steatosis through Activation of PPARγ and Fatty Acid Uptake.

Transgenic mice (Tg) overexpressing human apolipoprotein D (H-apoD) in the brain are resistant to neurodegeneration. Despite the use of a neuron-specific promoter to generate the Tg mice, they expressed significant levels of H-apoD in both plasma and liver and they slowly develop hepatic steatosis and insulin resistance. We show here that hepatic PPARγ expression in Tg mice is increased by 2-fold compared to wild type (WT) mice. Consequently, PPARγ target genes Plin2 and Cide A/C are overexpressed, leading to increased lipid droplets formation. Expression of the fatty acid transporter CD36, another PPARgamma target, is also increased in Tg mice associated with elevated fatty acid uptake as measured in primary hepatocytes. Elevated expression of AMPK in the liver of Tg leads to phosphorylation of acetyl CoA carboxylase, indicating a decreased activity of the enzyme. Fatty acid synthase expression is also induced but the hepatic lipogenesis measured in vivo is not significantly different between WT and Tg mice. In addition, expression of carnitine palmitoyl transferase 1, the rate-limiting enzyme of beta-oxidation, is slightly upregulated. Finally, we show that overexpressing H-apoD in HepG2 cells in presence of arachidonic acid (AA), the main apoD ligand, increases the transcriptional activity of PPARγ. Supporting the role of apoD in AA transport, we observed enrichment in hepatic AA and a decrease in plasmatic AA concentration. Taken together, our results demonstrate that the hepatic steatosis observed in apoD Tg mice is a consequence of increased PPARγ transcriptional activity by AA leading to increased fatty acid uptake by the liver.