Carnitine Palmitoyltransferase 1B Research Articles

Active individuals have high mitochondrial content and oxidative markers in their abdominal subcutaneous adipose tissue.

Exercise training (training) effects on white adipose tissue (WAT) thermogenic and oxidative capacities in humans are inconclusive. This study aimed to investigate whether an active lifestyle is characterized by thermogenic and/or oxidative transcriptional markers in human WAT. In vivo maximal muscle ATP synthetic rates (ATPmax) were measured by 31 P-MRS, body composition by DXA, and peak oxygen uptake (VO2 peak) by cycle ergometry in active (n = 7) and sedentary (SED) individuals before and after 3 weeks of training (n = 9, SED only). mRNA expressions of brown adipose and β-oxidation markers, as well as mitochondrial DNA content (mtDNA), were measured by qRT-PCR and qPCR, respectively, in WAT. ATPmax and VO2 peak were higher in active versus SED individuals. Following training in SED individuals, ATPmax and VO2 peak increased. Proliferator-activated receptor gamma coactivator-1α and carnitine palmitoyltransferase-1β gene expressions and mtDNA content were significantly higher in WAT of active versus SED individuals before training. mRNA contents of brown and beige-specific markers were not different between cohorts. Training effectively increased ATPmax and VO2 peak but had no effect on mtDNA content or expressions of genes that regulate thermogenic and oxidative capacities in WAT. Results indicate that an active lifestyle is characterized by elevated mitochondrial content and oxidative, not thermogenic, markers of WAT.

Molecular characterization and nutritional regulation of carnitine palmitoyltransferase (CPT) family in grass carp (Ctenopharyngodon idellus).

The carnitine palmitoyltransferase (CPT) gene family plays an essential role in fatty acid β-oxidation in the mitochondrion. We identified six isoforms of the CPT family in grass carp and obtained their complete coding sequences (CDS). The isoforms included CPT 1α1a, CPT 1α1b, CPT 1α2a, CPT 1α2b, CPT 1β, and CPT 2, which may have resulted from fish-specific genome duplication. Sequence analysis showed that the predicted protein structure was different among the CPT gene family members in grass carp. The N-terminal domain of grass carp CPT 1α1a, CPT 1α1b, CPT 1α2a, and CPT 1α2b contained two transmembrane region domains and two acyltransferase choActase domains that exist in human and mouse proteins also; however, only one acyltransferase choActase domain was found in grass carp CPT 1β. The grass carp CPT 2 had two acyltransferase choActase domains. The grass carp CPT 1α1b, CPT 1α2a, CPT 1α2b, and CPT 1β contained 18 coding exons, while CPT 1α1a and CPT 2 consisted of 17 coding exons and 5 coding exons, respectively. The mRNA of the six CPT isoforms was expressed in a wide range of tissues, but the mRNA abundance of each CPT showed tissue-dependent expression patterns. The expression of CPT 1α1a, CPT 1α2a, and CPT 1β at 48h post-feeding was significantly increased in the liver (P<0.01, P<0.05, and P<0.01, respectively). The diverse responses of multiple isoforms in the liver during nutritional limitation suggest that they may play different roles in fatty acid β-oxidation.

Effects of fetal calf serum on cGMP pathway and oocyte lipid metabolism in vitro.

Intracellular levels of cyclic nucleotides, such as cGMP, are involved in the regulation of adipocyte lipolysis. Cumulus-oocyte complexes (COCs) express enzymes that both synthesise (guanylate cyclase) and degrade (phosphodiesterase (PDE) 5A) cGMP. Because serum interferes with lipid metabolism, its effects on the cGMP pathway and lipid content in bovine COCs were examined. COCs were matured in medium containing fetal calf serum (FCS; 2% or 10%) or 0.4% bovine serum albumin (BSA; control). At both 2% and 10%, FCS decreased cGMP levels in COCs compared with BSA (0.64 and 1.04 vs 9.46 fmol per COC respectively; P<0.05) and decreased transcript levels of guanylate cyclase 1, soluble, beta 3 (GUCY1B3), whereas PDE5A levels were increased. FCS also affected the expression of genes related to lipolysis, increasing relative expression of perilipin 2 (PLIN2) and carnitine palmitoyltransferase 1B (CPT1B) in cumulus cells. Effects of FCS and cGMP on the lipid content of oocytes and embryos were evaluated by Nile red staining. COCs were matured with 10% FCS, FCS+10-5 M sildenafil (SDF), a PDE5 inhibitor, or 0.4% BSA. The lipid content was increased in oocytes matured in FCS compared with BSA (fluorescence intensity 20.1 vs 17.61 respectively; P<0.05), whereas the lipid content in oocytes matured in FCS+SDF (fluorescence intensity 16.33) was similar to that in the BSA-treated group (P>0.05). In addition, lipid content was higher in embryos from oocytes matured with FCS than BSA (fluorescence intensity 31.12 vs 22.31 respectively; P<0.05), but was increased even further in the FCS+SDF-treated group (fluorescence intensity 40.35; P<0.05), possibly due to a compensatory mechanism during embryo culture without SDF for the reduction in lipid content during IVM. The present study provides, for the first time, evidence that the cGMP pathway may be involved in lipid metabolism in bovine COCs and that this pathway is affected by FCS.

Antilipolytic and antilipogenic effects of the CPT-1b inhibitor oxfenicine in the white adipose tissue of rats.

Oxfenicine is a carnitine-palmitoyl transferase 1b (CPT-1b)-specific inhibitor that has been shown to improve whole body insulin sensitivity while suppressing fatty acid (FA) oxidation and increasing circulating FA. Because the white adipose tissue (WAT) is an organ that stores and releases FAs, this study investigated whether oxfenicine-induced inhibition of FA oxidation affected adiposity and WAT metabolism in rats fed either low (LF) or high-fat (HF) diets. Following 8 wk of dietary intervention, male Sprague-Dawley rats were given a daily intraperitoneal injection of oxfenicine (150 mg/kg body wt) or vehicle (PBS) for 3 wk. Oxfenicine treatment reduced whole body fat oxidation, body weight, and adiposity, and improved insulin sensitivity in HF-fed rats. All of these effects occurred without alterations in food intake, energy expenditure, and ambulatory activity. In vivo oxfenicine treatment reduced FA oxidation and lipolysis in subcutaneous inguinal (SC Ing) adipocytes, whereas glucose incorporation into lipids (lipogenesis) was significantly reduced in both SC Ing and epididymal (Epid) adipocytes. In summary, our results show that oxfenicine-induced inhibition of CPT-1b markedly affects WAT metabolism, leading to reduced adiposity through a mechanism that involves reduced lipogenesis in the SC Ing and Epid fat depots of rats.

Effects of pterostilbene in brown adipose tissue from obese rats.

In recent years, much attention has been paid by the scientific community to phenolic compounds as active biomolecules naturally present in foods. Pterostilbene is a resveratrol dimethylether derivative which shows higher bioavailability. The aim of the present study was to analyze the effect of pterostilbene on brown adipose tissue thermogenic markers in a model of genetic obesity, which shows reduced thermogenesis. The experiment was conducted with 30 Zucker (fa/fa) rats that were distributed in three experimental groups: control and two groups orally administered with pterostilbene at 15 and 30mg/kg body weight/day for 6weeks. Gene expression of uncoupling protein 1 (Ucp1), peroxisome proliferator-activated receptor γ co-activator 1 α (Pgc-1α), carnitine palmitoyl transferase 1b (Cpt1b), peroxisome proliferator-activated receptor α (Pparα), nuclear respiratory factor 1 (Nfr1), and cyclooxygenase-2 (Cox-2); protein expression of PPARα, PGC-1α, p38 mitogen-activated protein kinase (p38 MAPK), UCP1 and glucose transporter (GLUT4); and enzyme activity of CPT 1b and citrate synthase (CS) were assessed in interscapular brown adipose tissue. With the exception of Pgc-1α expression, all these parameters were significantly increased by pterostilbene administration. These results show for the first time that pterostilbene increases thermogenic and oxidative capacity of brown adipose tissue in obese rats. Whether these effects effectively contribute to the antiobesity properties of these compound needs further research.

Abstract 301: Initial Increase of Klf5 and Ppara Expression After Myocardial Ischemia/Reperfusion in Mice Appears to be Critical for Survival

Krüppel-like factors (KLF) have important roles in metabolism. We previously found that KLF5 is a positive transcriptional regulator of peroxisome proliferator-activated receptor α ( Ppara) , a central regulator of cardiac fatty acid oxidation (FAO). Mice with cardiomyocyte-specific Klf5 ablation ( α MHC-Klf5 -/- ) had reduced cardiac Ppara expression and FAO. At age 6-12 months these mice develop distinct cardiac dysfunction. The role of PPARα activation in I/R injury is unclear as both beneficial and detrimental effects have been reported. We aimed to study if Ppara expression changes during I/R are driven by KLF5 and explore its protective or detrimental role. Wild type mice were subjected to in vivo I/R or sham surgery. I/R resulted in an initial increase in Ppara , and its target gene pyruvate dehydrogenase kinase 4 ( Pdk4) mRNA after 2h reperfusion, followed by decreased expression after 24h reperfusion. The Ppara expression is associated with parallel changes in cardiac Klf5 mRNA expression. Concurrent, there was a decrease of cardiac FAO-related genes carnitine palmitoyl-transferase 1β ( Cpt1b), very long chain acyl-CoA dehydrogenase (Vlcad), and acyl-CoA oxidase ( Aox) in mice with I/R. To define the cell type causing the temporal changes in Klf5 and Ppara after I/R we isolated primary cardiomyocytes and fibroblasts. Our data suggest a similar effect in primary isolated cardiomyocytes only. Klf5 mRNA expression is increased after 2 hour hypoxia and normalized after 4 hour re-oxygenation in cardiomyocytes, whereas there are no changes after hypoxia/normoxia in fibroblasts. To assess the importance of cardiomyocyte KLF5 in I/R we used α MHC-Klf5 -/- mice. Interestingly, despite reduced FAO, 7 month old αMHC-Klf5 -/- mice subjected to I/R had a marked increase in mortality; 4 of 7 αMHC-Klf5 -/- mice died within the first 24h of reperfusion while no mortality was observed in age-matched wild type mice that underwent I/R. In conclusion, I/R is associated with an increase in Klf5 and Ppara in the first hours of reperfusion followed by a decrease in Klf5 and Ppara , likely accounted for by cardiomyocytes. Increased mortality for α MHC-Klf5 -/- mice with I/R injury suggests that the initial increase may be an adaptive response that is critical for survival.

Evaluation of polygenic risks for narcolepsy and essential hypersomnia.

In humans, narcolepsy is a sleep disorder that is characterized by sleepiness, cataplexy and rapid eye movement (REM) sleep abnormalities. Essential hypersomnia (EHS) is another type of sleep disorder that is characterized by excessive daytime sleepiness without cataplexy. A human leukocyte antigen (HLA) class II allele, HLA-DQB1*06:02, is a major genetic factor for narcolepsy. Almost all narcoleptic patients are carriers of this HLA allele, while 30-50% of EHS patients and 12% of all healthy individuals in Japan carry this allele. The pathogenesis of narcolepsy and EHS is thought to be partially shared. To evaluate the contribution of common single-nucleotide polymorphisms (SNPs) to narcolepsy onset and to assess the common genetic background of narcolepsy and EHS, we conducted a polygenic analysis that included 393 narcoleptic patients, 38 EHS patients with HLA-DQB1*06:02, 119 EHS patients without HLA-DQB1*06:02 and 1582 healthy individuals. We also included 376 individuals with panic disorder and 213 individuals with autism to confirm whether the results were biased. Polygenic risks in narcolepsy were estimated to explain 58.1% (PHLA-DQB1*06:02=2.30 × 10-48, Pwhole genome without HLA-DQB1*06:02=6.73 × 10-2) including HLA-DQB1*06:02 effects and 1.3% (Pwhole genome without HLA-DQB1*06:02=2.43 × 10-2) excluding HLA-DQB1*06:02 effects. The results also indicated that small-effect SNPs contributed to the development of narcolepsy. Reported susceptibility SNPs for narcolepsy in the Japanese population, CPT1B (carnitine palmitoyltransferase 1B), TRA@ (T-cell receptor alpha) and P2RY11 (purinergic receptor P2Y, G-protein coupled, 11), were found to explain 0.8% of narcolepsy onset (Pwhole genome without HLA-DQB1*06:02=9.74 × 10-2). EHS patients with HLA-DQB1*06:02 were estimated to have higher shared genetic background to narcoleptic patients than EHS patients without HLA-DQB1*06:02 even when the effects of HLA-DQB1*06:02 were excluded (EHS with HLA-DQB1*06:02: 40.4%, PHLA-DQB1*06:02=7.02 × 10-14, Pwhole genome without HLA-DQB1*06:02=1.34 × 10-1, EHS without HLA-DQB1*06:02: 0.4%, Pwhole genome without HLA-DQB1*06:02=3.06 × 10-1). Meanwhile, the polygenic risks for narcolepsy could not explain the onset of panic disorder and autism, suggesting that our results were reasonable.

Impaired Mitochondrial Fat Oxidation Induces FGF21 in Muscle.

Fatty acids are the primary fuel source for skeletal muscle during most of our daily activities, and impaired fatty acid oxidation (FAO) is associated with insulin resistance. We have developed a mouse model of impaired FAO by deleting carnitine palmitoyltransferase-1b specifically in skeletal muscle(Cpt1b(m-/-)). Cpt1b(m-/-) mice have increased glucose utilization and are resistant to diet-induced obesity. Here, we show that inhibition of mitochondrial FAO induces FGF21 expression specifically in skeletal muscle. The induction of FGF21 in Cpt1b-deficient muscle is dependent on AMPK and Akt1 signaling but independent of the stress signaling pathways. FGF21 appears to act in a paracrine manner to increase glucose uptake under low insulin conditions, but it does not contribute to the resistance to diet-induced obesity.

Tri-m-cresyl phosphate and PPAR/LXR interactions in seabream hepatocytes: revealed by computational modeling (docking) and transcriptional regulation of signaling pathways.

The interactions between tri-m-cresyl phosphate (TMCP; an organophosphate flame retardant) and peroxisome proliferator activated receptors (PPARs) or liver X receptor α (LXRα) were investigated in seabream hepatocytes. The study was designed to characterize the binding of TMCP to PPARα, PPARγ and LXRα by computational modeling (docking) and transcriptional regulation of signaling pathways. TMCP mainly established a non-polar interaction with each receptor. These findings reflect the hydrophobic nature of this binding site, with fish LXRα showing the highest binding efficiency. Further, we have investigated the ability of TMCP to activate PPAR and LXR controlled transcriptional processes involved in lipid/cholesterol metabolism. TMCP induced the expression of all the target genes measured. All target genes were up-regulated at all exposure doses, except for fatty acid binding protein 7 (FABP7) and carnitine palmitoyltransferase 1B. Collectively, our data indicate that TMCP can affect fatty acid synthesis/uptake and cholesterol metabolism through LXRα and PPARs, together with interactions between these transcription factors in seabream liver.

Anti-inflammatory and metabolic effects of remote ischemic preconditioning and postconditioning on the contractile performance of the diaphragm in endotoxemic rats

Background Respiratory failure is a major cause of mortality during septic shock and is due in part to the decreased ventilatory muscles contraction. These muscles depend mainly on fatty acid oxidation as an important source of ATP. We investigated the effects of remote ischemic preconditioning and postconditioning (RpostC) on the contractile functions of the diaphragm in relation to metabolic functions during systemic inflammation in lipopolysaccharide (LPS)-induced endotoxemia model. Materials and methods A total of 24 adult male albino rats were divided equally into four groups: (i) the control group (group 1); (ii) LPS group (group 2), in which rats were treated with a single intraperitoneal injection of LPS (0.8 mg/kg intraperitoneal single dose); (iii) preconditioned group (group 3), in which remote ischemic preconditioning was induced with three ischemia/reperfusion cycles of the right hind limbs just before LPS injection; and (iv) postconditioned group (group 4), in which remote ischemic postconditioning was induced as in group 3 just after LPS injection. The animals were killed 5 days after the treatment. Among all groups, the contractility of the diaphragm was examined and the gene expressions of the carnitine palmitoyl transferase 1β (CPT-10β), the nuclear receptor peroxisome proliferator-activated receptor-α (PPARα), peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), and the nuclear factor erythroid 2-related factor 2 ( Nrf2) - the master of antioxidant response element - by real-time reverse transcription-PCR in the rat diaphragm tissue were determined; in addition, the serum levels of inflammatory markers, tumor necrosis factor α (TNFα) and interleukin-6, and lipids were measured. Results Both types of remote ischemic, preconditioning and postconditioning, significantly improved the contractile performance of the diaphragm ( P Conclusion Our results showed that the improvement of contractile performance of the diaphragm during sepsis was related to the improvement in the expression of nuclear hormone receptors involved in fat oxidation and modulation in oxidative stress and its consequences on inflammatory response. On the basis of these findings, we can suggest that early rational postconditioning interventions may be one of the promising strategies in the management of sepsis.

Anti-inflammatory and metabolic effects of remote ischemic preconditioning and postconditioning on the contractile performance of the diaphragm in endotoxemic rats

BackgroundRespiratory failure is a major cause of mortality during septic shock and is due in part to the decreased ventilatory muscles contraction. These muscles depend mainly on fatty acid oxidation as an important source of ATP. We investigated the effects of remote ischemic preconditioning and postconditioning (RpostC) on the contractile functions of the diaphragm in relation to metabolic functions during systemic inflammation in lipopolysaccharide (LPS)-induced endotoxemia model.Materials and methodsA total of 24 adult male albino rats were divided equally into four groups: (i) the control group (group 1); (ii) LPS group (group 2), in which rats were treated with a single intraperitoneal injection of LPS (0.8 mg/kg intraperitoneal single dose); (iii) preconditioned group (group 3), in which remote ischemic preconditioning was induced with three ischemia/reperfusion cycles of the right hind limbs just before LPS injection; and (iv) postconditioned group (group 4), in which remote ischemic postconditioning was induced as in group 3 just after LPS injection. The animals were killed 5 days after the treatment. Among all groups, the contractility of the diaphragm was examined and the gene expressions of the carnitine palmitoyl transferase 1β (CPT-10β), the nuclear receptor peroxisome proliferator-activated receptor-α (PPARα), peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), and the nuclear factor erythroid 2-related factor 2 ( Nrf2) - the master of antioxidant response element - by real-time reverse transcription-PCR in the rat diaphragm tissue were determined; in addition, the serum levels of inflammatory markers, tumor necrosis factor α (TNFα) and interleukin-6, and lipids were measured.ResultsBoth types of remote ischemic, preconditioning and postconditioning, significantly improved the contractile performance of the diaphragm ( P < 0.001) compared with rats in the LPS group. These improvements were accompanied with significant elevation in the diaphragmatic expression of PPARα, PGC-1α, and CPT-1β, together with decreased serum lipids. In addition, there was a significant improvement in Nrf2 with a reduction in serum TNFα and interleukin-6.ConclusionOur results showed that the improvement of contractile performance of the diaphragm during sepsis was related to the improvement in the expression of nuclear hormone receptors involved in fat oxidation and modulation in oxidative stress and its consequences on inflammatory response. On the basis of these findings, we can suggest that early rational postconditioning interventions may be one of the promising strategies in the management of sepsis.

Myocardial expression profiles of candidate molecules in patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia compared to those with dilated cardiomyopathy and healthy controls

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is mainly an autosomal dominant disease characterized by fibrofatty infiltration of the right ventricle, leading to ventricular arrhythmias. Mutations in desmosomal proteins can be identified in about half of the patients. The pathogenic mechanisms leading to disease expression remain unclear. The purpose of this study was to investigate myocardial expression profiles of candidate molecules involved in the pathogenesis of ARVC/D. Myocardial messenger RNA (mRNA) expression of 62 junctional molecules, 5 cardiac ion channel molecules, 8 structural molecules, 4 apoptotic molecules, and 6 adipogenic molecules was studied. The averaged expression of candidate mRNAs was compared between ARVC/D samples (n = 10), nonfamilial dilated cardiomyopathy (DCM) samples (n = 10), and healthy control samples (n = 8). Immunohistochemistry and quantitative protein expression analysis were performed. Genetic analysis using next generation sequencing was performed in all patients with ARVC/D. Following mRNA levels were significantly increased in patients with ARVC/D compared to those with DCM and healthy controls: phospholamban (P ≤ .001 vs DCM; P ≤ .001 vs controls), healthy tumor protein 53 apoptosis effector (P = .001 vs DCM; P ≤ .001 vs controls), and carnitine palmitoyltransferase 1β (P ≤ .001 vs DCM; P = 0.008 vs controls). Plakophillin-2 (PKP-2) mRNA was downregulated in patients with ARVC/D with PKP-2 mutations compared with patients with ARVC/D without PKP-2 mutations (P = .04). Immunohistochemistry revealed significantly increased protein expression of phospholamban, tumor protein 53 apoptosis effector, and carnitine palmitoyltransferase 1β in patients with ARVC/D and decreased PKP-2 expression in patients with ARVC/D carrying a PKP-2 mutation. Changes in the expression profiles of sarcolemmal calcium channel regulation, apoptosis, and adipogenesis suggest that these molecular pathways may play a critical role in the pathogenesis of ARVC/D, independent of the underlying genetic mutations.

Abstract 16082: Plin2 Attenuates Cardiomyocyte Lipotoxicity

Diabetic cardiomyopathy is associated with excess lipid accumulation in the heart. We previously showed that oleate, a non-toxic mono-unsaturated fatty acid causes the formation of abundant lipid droplets in cardiomyocytes that were lined with Plin2, an important lipid droplet binding protein. In contrast, palmitate, a toxic saturated fatty acid, led to the formation of aberrant lipid droplets which lacked Plin2 immunoreactivity. Hypothesis: We hypothesized that Plin2 overexpression may protect against palmitate mediated lipotoxicity. Methods: We overexpressed and silenced Plin2 in rat neonatal cardiomyocytes (NCMs) by LentiVector mediated overexpression of Plin2 cDNA and shRNAs, respectively. We treated these NCMs with bovine serum albumin (51μM, vehicle control), 100-300μM oleate, or 100-300μM palmitate for 4-24 hours. We evaluated viability with the propidium iodide exclusion assay and measured gene expression by qRT-PCR. Results: Plin2 overexpression protected NCMs from the lipotoxic effects of palmitate. Conversely, silencing of Plin2 sensitized NCMs to the effects of palmitate and caused oleate, which is normally non-toxic, to induce cell death in NCMs. Interestingly, we found that Plin2 overexpression had a marked stimulatory effect on several PPAR target genes including Carnitine palmitoyl transferase 1b (Cpt1b), the rate limiting enzyme in β-oxidation. In contrast, Plin2 silencing led to a significant decrease in oleate induced expression of PPAR target genes, including Cpt1b. Conclusion: Here we showed that overexpression of Plin2, a key lipid droplet binding protein protected against lipotoxicity, while silencing it caused lipotoxicity. We show that this may be due to alterations in lipid metabolism, since Plin2 overexpression led to increased expression of key β-oxidation genes. This is important because we have previously shown that palmitate impairs β-oxidation capacity in cardiomyocytes. Therefore enhancing β-oxidation may attenuate lipotoxicity by limiting the build-up of lipid metabolites. The mechanism of Plin2 mediated effects on PPAR target gene expression, as well as the effect on lipid droplet formation are the subject of on-going studies.

Loss of Adipocyte VEGF Impairs Endurance Exercise Capacity in Mice.

Reducing vascular endothelial growth factor (VEGF) in adipose tissue alters adipose vascularity and metabolic homeostasis. We hypothesized that this would also affect metabolic responses during exercise-induced stress and that adipocyte-specific VEGF-deficient (adipoVEGF-/-) mice would have impaired endurance capacity. Endurance exercise capacity in adipoVEGF-/- (n = 10) and littermate control (n = 11) mice was evaluated every 4 wk between 6 and 24 wk of age using a submaximal endurance run to exhaustion at 20 m·min(-1) at 10° incline. Maximal running speed, using incremental increases in speed at 30-s intervals, was tested at 25 and 37 wk of age. White and brown adipose tissue capillarity were reduced by 40% in adipoVEGF-/-, and no difference in skeletal muscle capillarity was observed. Endurance run time to exhaustion was 30% lower in adipoVEGF-/- compared with that in controls at all time points (P < 0.001), but no difference in maximal running speed was observed between the groups. After exercise (1 h at 50% maximum running speed), adipoVEGF-/- mice displayed lower circulating insulin (P < 0.001), lower glycerol (P < 0.05), and tendency for lower blood glucose (P = 0.06) compared with controls. There was no evidence of altered oxidative damage or changes in carnitine palmitoyltransferase-1β expression in skeletal muscle of adipoVEGF-/- mice. These data suggest that VEGF-mediated deficits in adipose tissue blunt the availability of lipid substrates during endurance exercise, which likely reduced endurance performance. Surprisingly, we also found an unchanged basal blood glucose despite lower circulating insulin in adipoVEGF-/- mice, suggesting that loss of adipocyte VEGF can blunt insulin release and/or increase basal insulin sensitivity.

Effects of a high milk intake during the pre-weaning period on nutrient metabolism and growth rate in Japanese Black cattle.

This study aimed to determine the effects of feeding an increased volume of high-fat milk during the early post-natal life on metabolite concentrations in the blood, the expression of key genes regulating intermediary metabolism in the skeletal muscles, and the rate of growth of Japanese Black cattle. All calves were fed a high-fat milk replacer (crude protein, 26%; crude fat, 25.5%; total dissolved nitrogen, 116%). Control calves (n = 4) were nursed with 500 g milk replacer until 3 months of age, whereas calves in the experimental group (n = 4) were nursed with 1800 g milk replacer until 3 months, and then the volume was gradually reduced until 5 months. Body weight was significantly higher in the experimental group than in the control group at 7 months. Plasma glucose concentrations were significantly lower in the experimental group. Expression of glucose-transporter-4 messenger RNA (mRNA) was lower, whereas that of glucose transporter 1, cluster of differentiation 36, and carnitine palmitoyltransferase-1b mRNA was significantly higher in the Longissimus thoracis of the experimental group. Nutritional status during early post-natal life appears to strongly influence the growth rate and glucose and lipid metabolism in Japanese Black cattle.

Ginsenoside Rg1 Improves In vitro-produced Embryo Quality by Increasing Glucose Uptake in Porcine Blastocysts.

Ginsenoside Rg1 is a natural compound with various efficacies and functions. It has beneficial effects on aging, diabetes, and immunity, as well as antioxidant and proliferative functions. However, its effect on porcine embryo development remains unknown. We investigated the effect of ginsenoside Rg1 on the in vitro development of preimplantation porcine embryos after parthenogenetic activation in high-oxygen conditions. Ginsenoside treatment did not affect cleavage or blastocyst formation rates, but did increase the total cell number and reduced the rate of apoptosis. In addition, it had no effect on the expression of four apoptosis-related genes (Bcl-2 homologous antagonist/killer, B-cell lymphoma-extra large, Caspase 3, and tumor protein p53) or two metabolism-related genes (mechanistic target of rapamycin, carnitine palmitoyltransferase 1B), but increased the expression of Glucose transporter 1 (GLUT1), indicating that it may increase glucose uptake. In summary, treatment with the appropriate concentration of ginsenoside Rg1 (20 μg/mL) can increase glucose uptake, thereby improving the quality of embryos grown in high-oxygen conditions.

Bovine serum albumin as the dominant form of dietary protein reduces subcutaneous fat mass, plasma leptin and plasma corticosterone in high fat-fed C57/BL6J mice.

Increasing evidence suggests that the source of dietary protein can have an impact on weight gain and fat mass during high-fat feeding in both humans and rodents. The present study examined whether dietary bovine serum albumin (BSA) as the dominant source of protein alters energy balance and adiposity associated with high-fat feeding. C57/BL6J mice were given a diet with 10 % of energy from fat and 20 % of energy from casein or a diet with 45 % of energy from fat and either 20 % of energy from casein (HFD) or BSA (HFD+BSA) for 13 weeks. The HFD+BSA diet did not significantly alter daily energy expenditure, locomotor activity and RER, but did increase cumulative energy intake and percentage of lean mass while reducing feed efficiency and percentage of fat mass when compared with the HFD (P< 0·05). In subcutaneous adipose tissue (SAT), the HFD+BSA diet increased the mRNA levels of PPARα (PPARA), carnitine palmitoyltransferase 1b (CPT1b) and uncoupling protein 3 (UCP3), but reduced the mRNA level of leptin when compared with the HFD (P< 0·05). The SAT mRNA levels of PPARA, CPT1b and UCP3 were negatively correlated (P< 0·05) with SAT mass, which was reduced in HFD+BSA mice compared with HFD controls (P< 0·01). No differences in epididymal fat mass existed between the groups. The HFD+BSA diet normalised plasma leptin and corticosterone levels compared with the HFD (P< 0·05). While differences in leptin levels were associated with the percentage of fat mass (P< 0·01), changes in corticosterone concentrations were independent of the percentage of fat mass (P< 0·05). The data suggest that the HFD+BSA diet influences plasma leptin levels via SAT mass reduction where mRNA levels of genes linked to β-oxidation were increased, whereas differences in plasma corticosterone levels were not related to fat mass reduction.

Differential regulation of the expression of lipid metabolism-related genes with skeletal muscle type in growing chickens.

The regulatory mechanisms of carbohydrate and lipid metabolism are known to differ among skeletal muscle types in mammals. For example, glycolytic muscles prefer glucose as an energy source, whereas oxidative muscles prefer fatty acids (FA). We herein demonstrated differences in the expression of genes involved in carbohydrate and lipid metabolism in the pectoralis major (a glycolytic twitch muscle), adductor superficialis (an oxidative twitch muscle), and adductor profound (a tonic muscle) of 14-day-old chicks. Under ad libitum feeding conditions, the mRNA levels of muscle type phosphofructokinase-1 were markedly lower in the adductor superficialis muscle, suggesting that basal glycolytic activity is very low in this type of muscle. In contrast, high mRNA levels of lipoprotein lipase (LPL) and fatty acid translocase/cluster of differentiation 36 (FAT/CD36) in the adductor superficialis muscle suggest that FA uptake is high in this type of muscle. The mRNA levels of adipose triglyceride lipase (ATGL) and carnitine palmitoyltransferase 1b (CPT1b) were significantly higher in the adductor profound muscle than in other muscles, suggesting that basal lipolytic activity is high in this type of muscle. Furthermore, the mRNA levels of peroxisome proliferator activated receptor δ and CPT1b were significantly increased in the adductor superficialis muscle, but not in other muscles, after 24h of fasting. Therefore, the availability of FA in the oxidative twitch muscles in growing chickens appears to be upregulated by fasting. Our results suggest that lipid metabolism-related genes are upregulated under both basal and fasting conditions in the adductor superficialis in growing chickens.

Differential epigenetic and transcriptional response of the skeletal muscle carnitine palmitoyltransferase 1B (CPT1B) gene to lipid exposure with obesity.

The ability to increase fatty acid oxidation (FAO) in response to dietary lipid is impaired in the skeletal muscle of obese individuals, which is associated with a failure to coordinately upregulate genes involved with FAO. While the molecular mechanisms contributing to this metabolic inflexibility are not evident, a possible candidate is carnitine palmitoyltransferase-1B (CPT1B), which is a rate-limiting step in FAO. The present study was undertaken to determine if the differential response of skeletal muscle CPT1B gene transcription to lipid between lean and severely obese subjects is linked to epigenetic modifications (DNA methylation and histone acetylation) that impact transcriptional activation. In primary human skeletal muscle cultures the expression of CPT1B was blunted in severely obese women compared with their lean counterparts in response to lipid, which was accompanied by changes in CpG methylation, H3/H4 histone acetylation, and peroxisome proliferator-activated receptor-δ and hepatocyte nuclear factor 4α transcription factor occupancy at the CPT1B promoter. Methylation of specific CpG sites in the CPT1B promoter that correlated with CPT1B transcript level blocked the binding of the transcription factor upstream stimulatory factor, suggesting a potential causal mechanism. These findings indicate that epigenetic modifications may play important roles in the regulation of CPT1B in response to a physiologically relevant lipid mixture in human skeletal muscle, a major site of fatty acid catabolism, and that differential DNA methylation may underlie the depressed expression of CPT1B in response to lipid, contributing to the metabolic inflexibility associated with severe obesity.

Mitochondria-focused gene expression profile reveals common pathways and CPT1B dysregulation in both rodent stress model and human subjects with PTSD.

Posttraumatic stress disorder (PTSD), a trauma-related mental disorder, is associated with mitochondrial dysfunction in the brain. However, the biologic approach to identifying the mitochondria-focused genes underlying the pathogenesis of PTSD is still in its infancy. Previous research, using a human mitochondria-focused cDNA microarray (hMitChip3) found dysregulated mitochondria-focused genes present in postmortem brains of PTSD patients, indicating that those genes might be PTSD-related biomarkers. To further test this idea, this research examines profiles of mitochondria-focused gene expression in the stressed-rodent model (inescapable tail shock in rats), which shows characteristics of PTSD-like behaviors and also in the blood of subjects with PTSD. This study found that 34 mitochondria-focused genes being upregulated in stressed-rat amygdala. Ten common pathways, including fatty acid metabolism and peroxisome proliferator-activated receptors (PPAR) pathways were dysregulated in the amygdala of the stressed rats. Carnitine palmitoyltransferase 1B (CPT1B), an enzyme in the fatty acid metabolism and PPAR pathways, was significantly over-expressed in the amygdala (P<0.007) and in the blood (P<0.01) of stressed rats compared with non-stressed controls. In human subjects with (n=28) or without PTSD (n=31), significant over-expression of CPT1B in PTSD was also observed in the two common dysregulated pathways: fatty acid metabolism (P=0.0027, false discovery rate (FDR)=0.043) and PPAR (P=0.006, FDR=0.08). Quantitative real-time polymerase chain reaction validated the microarray findings and the CPT1B result. These findings indicate that blood can be used as a specimen in the search for PTSD biomarkers in fatty acid metabolism and PPAR pathways, and, in addition, that CPT1B may contribute to the pathology of PTSD.