CPT1alpha over-expression increases long-chain fatty acid oxidation and reduces cell viability with incremental palmitic acid concentration in 293T cells

Sesamol counteracts on metabolic disorders of middle-aged alimentary obese mice through regulating skeletal muscle glucose and lipid metabolism

Background

Globally, obesity is a significant public problem, especially when aging. Sesamol, a phenolic lignan present in sesame seeds, might have a positive effect on high-fat diet (HFD)-induced obesity associated with aging.

Objective

The purpose of current research study was to explore salutary effects and mechanisms of sesamol in treating alimentary obesity and associated metabolic syndrome in middle-aged mice.

Methods

C57BL/6J mice aged 4–6 weeks and 6–8 months were assigned to the young normal diet group, middle-aged normal diet group, middle-aged HFD group, and middle-aged HFD + sesamol group. At the end of experiment, glucose tolerance test and insulin tolerance test were performed; the levels of lipids and oxidative stress-related factors in the serum and skeletal muscle were detected using chemistry reagent kits; lipid accumulation in skeletal muscle was observed by oil red O staining; the expressions of muscular glucose and lipid metabolism associated proteins were measured by Western blotting.

Results

Sesamol decreased the body weight and alleviated obesity-associated metabolism syndrome in middle-aged mice, such as glucose intolerance, insulin resistance, dyslipidemia, and oxidative stress. Moreover, muscular metabolic disorders were attenuated after treatment with sesamol. It increased the expression of glucose transporter type-4 and down-regulated the protein levels of pyruvate dehydrogenase kinase isozyme 4, implying the increase of glucose uptake and oxidation. Meanwhile, sesamol decreased the expression of sterol regulatory element binding protein 1c and up-regulated the phosphorylation of hormone-sensitive lipase and the level of carnitine palmityl transferase 1α, which led to the declined lipogenesis and the increased lipolysis and lipid oxidation. In addition, the SIRT1/AMPK signaling pathway was triggered by sesamol, from which it is understood how sesamol enhances glucose and lipid metabolism.

Conclusions

Sesamol counteracts on metabolic disorders of middle-aged alimentary obese mice through regulating skeletal muscle glucose and lipid metabolism, which might be associated with the stimulation of the SIRT1/AMPK pathway.

Mitochondrial Fission Governed by Drp1 Regulates Exogenous Fatty Acid Usage and Storage in Hela Cells

In the presence of high abundance of exogenous fatty acids, cells either store fatty acids in lipid droplets or oxidize them in mitochondria. In this study, we aimed to explore a novel and direct role of mitochondrial fission in lipid homeostasis in HeLa cells. We observed the association between mitochondrial morphology and lipid droplet accumulation in response to high exogenous fatty acids. We inhibited mitochondrial fission by silencing dynamin-related protein 1(DRP1) and observed the shift in fatty acid storage-usage balance. Inhibition of mitochondrial fission resulted in an increase in fatty acid content of lipid droplets and a decrease in mitochondrial fatty acid oxidation. Next, we overexpressed carnitine palmitoyltransferase-1 (CPT1), a key mitochondrial protein in fatty acid oxidation, to further examine the relationship between mitochondrial fatty acid usage and mitochondrial morphology. Mitochondrial fission plays a role in distributing exogenous fatty acids. CPT1A controlled the respiratory rate of mitochondrial fatty acid oxidation but did not cause a shift in the distribution of fatty acids between mitochondria and lipid droplets. Our data reveals a novel function for mitochondrial fission in balancing exogenous fatty acids between usage and storage, assigning a role for mitochondrial dynamics in control of intracellular fuel utilization and partitioning.

Lactobacillus fermentum CQPC07 attenuates obesity, inflammation and dyslipidemia by modulating the antioxidant capacity and lipid metabolism in high-fat diet induced obese mice

Background

Obesity is an epidemic disease in the world, the treatment and prevention of obesity methods have gained great attention. Lactobacillus is the main member of probiotics, and the physiological activity of it is specific to different strains. This study systematically explored the anti-obesity effect and possible mechanism of Lactobacillus fermentum CQPC07 (LF-CQPC07), which was isolated from pickled vegetables.

Results

LF-CQPC07 effectively controlled the weight gain of mice caused by a high-fat diet. The results of pathological sections indicated that LF-CQPC07 alleviated hepatocyte damage and fat accumulation in adipocytes. The detection of biochemical indictors revealed that LF-CQPC07 decreased the levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG), and increased the level of high-density lipoprotein cholesterol (HDL-C). Additionally, LF-CQPC07 caused the decrease in the amounts of inflammatory cytokines interleukin (IL)-1β, tumor necrosis factor-α (TNF-α), IL-6, and interferon-γ (IFN-γ), and the increase in the amounts of the anti-inflammatory cytokines IL-10 and IL-4. LF-CQPC07 also decreased the amounts of alanine aminotransferase (ALT), aspartate transaminase (AST), and alkaline phosphatase (ALP). Confirmed by qPCR, LF-CQPC07 enhanced the mRNA expression of catalase (CAT), gamma glutamylcysteine synthetase 1 (GSH1), copper/zinc superoxide dismutase (SOD1), manganese superoxide dismutase (SOD2), and glutathione peroxidase (GSH-Px). It also increased the mRNA expression levels of carnitine palmitoyltransferase 1 (CPT1), peroxisome proliferator-activated receptor alpha (PPAR-α), lipoprotein lipase (LPL), and cholesterol 7 alpha hydroxylase (CYP7A1), and decreased that of PPAR-γ and CCAAT/enhancer binding protein alpha (C/EBP-α) in the liver of mice.

Conclusion

This research confirmed that LF-CQPC07 is capable of ameliorating obesity, improving hyperlipemia, and alleviating chronic low-grade inflammation and liver injury accompanied with obesity. Its mechanism may be the regulation of antioxidant capacity and lipid metabolism. Therefore, LF-CQPC07 has enormous potential to serve as a potential probiotic for the prevention or treatment of obesity.

Berberine attenuates sodium palmitate-induced lipid accumulation, oxidative stress and apoptosis in grass carp(Ctenopharyngodon idella)hepatocyte in vitro

The objective of this work was to investigate the effect of berberine (BBR) on the Cell viability, lipid accumulation, apoptosis, cytochrome c, caspase-9 and caspase-3 in lipid accumulation-hepatocytes induced by sodium palmitate in vitro. The lipid accumulation-hepatocytes (induced by 0.5 mM sodium palmitate for 24 h) were treated with 5 μM berberine for 12 h. Then, the Cell viability, intracellular triglyceride (TG) content, lipid peroxide (LPO), malonaldehyde (MDA) content, cytochrome c, caspase-9, caspase-3 and apoptosis were detected. Sodium palmitate decreased Cell viability and increased intracellular TG content, lipid droplet accumulation, LPO and MDA concentrations, caused caspase-3 and caspase-9 activation, then led to apoptosis accompanied by cytochrome c release from mitochondria into the cytoplasm. Beberine could improve intracellular lipid droplet accumulation and oxidative stress, while reduce apoptosis induced by sodium palmitate.

Fermented Cordyceps militaris Extract Ameliorates Hepatosteatosis via Activation of Fatty Acid Oxidation

Nonalcoholic fatty liver disease is a progressive disease involving the accumulation of lipid droplets in the liver. In this study, we investigated the anti-hepatosteatosis effects of fermented Cordyceps militaris extract (CME) in AML-12 hepatocytes. Although the levels of adenosine and cordycepin were reduced in the extracts of CM grown on germinated soybean (GSCE) and fermented CM grown on germinated soybean (GSC) by Pediococcus pentosaceus ON188 (ON188E), the expression of fatty acid oxidation (FAO) genes were upregulated only by GSC-ON188E treatment in a dose-dependent manner. In contrast, a lipogenic gene, stearoyl Coenzyme A desaturase 1, was downregulated by ON188E. Formation of intracellular lipid droplets by the addition of oleic acid was reduced by ON188E to levels observed in WY14643-treated cells. When cells were treated with ON188E, sphingosine kinase 2 mainly responsible for hepatic sphingosine 1-phosphate (S1P) synthesis was upregulated and S1P was elevated. Collectively, the fermented GSC extract activates FAO through elevation of S1P synthesis and has potential as a therapeutic for hepatosteatosis.

Prevention of Obesity and Hyperlipidemia by Heptamethoxyflavone in High-fat Diet-induced Rats

Polymethoxyflavones (PMFs) have been shown to prevent obesity, ameliorate type 2 diabetes, and regulate lipid metabolism in vitro and in vivo. However, little is known about the contribution of 3,5,6,7,8,3',4'-heptamethoxyflavone (HMF) to prevent obesity and regulate lipid metabolism in vivo. We aimed to investigate the potential efficacy of HMF on preventing obesity and hyperlipidemia in rats fed a high-fat diet (HFD) and its underlying mechanisms. Male Sprague-Dawley rats were fed a normal diet or an HFD with or without HMF (0.02%, 0.04% and 0.08%, w/w) for 6 weeks. The supplementation of HMF not only significantly decreased body weight gain (HFD, 336.50 ± 18.84 g; LHMF, 309.43 ± 20.74 g; MHMF, 296.83 ± 13.88 g; HHMF, 265.71 ± 19.09 g; respectively, p < 0.05) and adipose tissues weight ( p < 0.05), but also markedly lowered serum levels of total cholesterol, triacylglycerol, and low-density lipoprotein cholesterol ( p < 0.05) in the sixth week in a dose-dependent manner compared with the HFD group. HMF also significantly alleviated hepatic steatosis in the liver (liver weight g/100 g body weight of HFD, 4.86 ± 0.11%; LHMF, 4.02 ± 0.33%; MHMF, 4.05 ± 0.31%; HHMF, 3.72 ± 0.34%; respectively, p < 0.05). Furthermore, transcriptome analysis and real-time quantitative RT-PCR demonstrated that HMF supplementation markedly downregulated hepatic genes related to adipogenesis transcription and inflammatory responses, and significantly upregulated genes related to fatty acid oxidation and energy expenditure. These results indicated that HMF could effectively prevent obesity and hyperlipidemia by regulation of the expression of lipid metabolism-related and inflammatory response-related genes.

Fatty acid oxidation is associated with proliferation and prognosis in breast and other cancers

Background

Altered cellular metabolism is a hallmark of cancer but the association between utilisation of particular metabolic pathways in tumours and patient outcome is poorly understood. We sought to investigate the association between fatty acid metabolism and outcome in breast and other cancers.

Methods

Cox regression analysis and Gene Set Enrichment Analysis (GSEA) of a gene expression dataset from primary breast tumours with well annotated clinical and survival information was used to identify genesets associated with outcome. A geneset representing fatty acid oxidation (FAO) was then examined in other datasets. A doxycycline-inducible breast cancer cell line model overexpressing the rate-limiting enzyme in FAO, carnitine palmitoyl transferase 1A (CPT1A) was generated and analysed to confirm the association between FAO and cancer-associated characteristics in vitro.

Results

We identified a gene expression signature composed of 19 genes associated with fatty acid oxidation (FAO) that was significantly associated with patient outcome. We validated this observation in eight independent breast cancer datasets, and also observed the FAO signature to be prognostic in other cancer types. Furthermore, the FAO signature expression was significantly downregulated in tumours, compared to normal tissues from a variety of anatomic origins. In breast cancer, the expression of CPT1A was higher in oestrogen receptor (ER)-positive, compared to ER-negative tumours and cell lines. Importantly, overexpression of CPT1A significantly decreased the proliferation and wound healing migration rates of MDA-MB231 breast cancer cells, compared to basal expression control.

Conclusions

Our findings suggest that FAO is downregulated in multiple tumour types, and activation of this pathway may lower cancer cell proliferation, and is associated with improved outcomes in some cancers.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4626-9) contains supplementary material, which is available to authorized users.

Fibroblast growth factor 21 and exercise-induced hepatic mitochondrial adaptations

Exercise stimulates hepatic mitochondrial adaptations; however, the mechanisms remain largely unknown. Here we tested whether FGF21 plays an obligatory role in exercise induced hepatic mitochondrial adaptations by testing exercise responses in FGF21 knockout mice. FGF21 knockout (FGF21-KO) and wild-type (WT) mice (11-12 wk of age) had access to voluntary running wheels for exercise (EX) or remained sedentary for 8 wk. FGF21 deficiency resulted in greater body weight, adiposity, serum cholesterol, insulin, and glucose concentrations compared with WT mice (P < 0.05). In addition, hepatic mitochondrial complete palmitate oxidation, β-hydroxyacyl-CoA dehydrogenase (β-HAD) activity, and nuclear content of PGC-1α were 30-50% lower in FGF21-KO mice compared with WT mice (P < 0.01). EX effectively lowered body weight, adiposity, serum triglycerides, free fatty acids, and insulin and normalized mitochondrial complete palmitate oxidation in the FGF21-KO mice, whereas the reduced hepatic β-HAD activity and lowered nuclear content of PGC-1α in FGF21-KO mice were not restored by EX. In addition, EX increased hepatic CPT-1α mRNA expression and ACC phosphorylation (a marker of increased AMPK activity) and reduced hepatic triacylglycerol content in both genotypes. However, FGF21-KO mice displayed a lower EX-induced increase in the mRNA expression of the hepatic gluconeogenic gene, PEPCK, compared with WT. In conclusion, FGF21 does not appear necessary for exercise-induced systemic and hepatic mitochondrial adaptations, but the increased adiposity, hyperinsulinemia, and impairments in hepatic mitochondrial function induced by FGF21 deficiency can be partially rescued by daily wheel running exercise.

Enhancing hepatic mitochondrial fatty acid oxidation stimulates eating in food-deprived mice

Hepatic fatty acid oxidation (FAO) has long been implicated in the control of eating. Nevertheless, direct evidence for a causal relationship between changes in hepatic FAO and changes in food intake is still missing. Here we tested whether increasing hepatic FAO via adenovirus-mediated expression of a mutated form of the key regulatory enzyme of mitochondrial FAO carnitine palmitoyltransferase 1A (CPT1mt), which is active but insensitive to inhibition by malonyl-CoA, affects eating and metabolism in mice. CPT1mt expression increased hepatocellular CPT1 protein levels. This resulted in an increase in circulating ketone body levels in fasted CPT1mt-expressing mice, suggesting an increase in hepatic FAO. These mice did not show any significant changes in cumulative food intake, energy expenditure, or respiratory quotient after 4-h food deprivation. After 24-h food deprivation, however, the CPT1mt-expressing mice displayed increased food intake. Thus expression of CPT1mt in the liver increases hepatic FAO capacity, but does not inhibit eating. Rather, it may even stimulate eating after prolonged food deprivation. These data do not support the hypothesis that an increase in hepatic FAO decreases food intake.

Weight loss herbal intervention therapy (W-LHIT) a non-appetite suppressing natural product controls weight and lowers cholesterol and glucose levels in a murine model

Background

The prevalence of obesity is increasing in industrialized countries. Obesity increases the risk of coronary artery disease, stroke, cancer, hypertension, and type-2 diabetes. Unfortunately, conventional obesity drug treatment is often associated with adverse effects. The objective of this study was to evaluate a novel natural formula, Weight loss herbal intervention therapy (W-LHIT), developed from traditional Chinese medicine, for weight control in a high-fat-diet (HFD) induced obesity murine model.

Methods

Two sets of experiments were performed. In experiment 1, 14-week-old C57BL/6 J male mice were fed with HFD for 21days and then separated into 3 weight-matched groups. One group continued on the HFD as obese-controls. Two groups were switched from HFD to normal fat level diet (NFD) and sham or W-LHIT treated. In experiment 2, 25-week-old obese mice, following 2weeks acclimatization, received either W-LHIT or sham treatment while maintained on HFD. In both sets of experiments, NFD fed, age matched normal weight mice served as normal controls. Body weight and food intake were recorded. Epididymal fat pad weight, serum glucose and cholesterol levels, as well as PPARγ and FABP4 gene expression in epididymal fat tissue were analyzed at the end of the experiment.

Results

In experiment 1, W-LHIT treated obese mice lost body weight 12.2 ± 3.8% whereas sham treated mice lost 5.5 ± 2.8% by day 10 after switching from the HFD to the NFD, without reduction of chow consumption. In experiment 2, W-LHIT treated obese mice maintained on the HFD had significantly lower body weight (8 fold less) than the sham treated mice. W-LHIT treatment also reduced epididymal fat pad weight, blood cholesterol and glucose levels versus sham treated mice without reduced chow consumption. In addition, significantly increased PPARγ (peroxisome proliferator activated receptor γ) and FABP4 (fatty acid binding protein 4) gene expression were found in epdidymal fat tissues. Liver and kidney function and hematology testing results of W-LHIT treated mice were within the normal range.

Conclusions

W-LHIT significantly and safely reduced body weight, normalized glucose and cholesterol levels in obese mice, without suppression of appetite, and increased adipocyte PPARγ and FABP4 gene expression.

Effects and action mechanisms of berberine and Rhizoma coptidis on gut microbes and obesity in high-fat diet-fed C57BL/6J mice

Gut microbes play important roles in regulating fat storage and metabolism. Rhizoma coptidis (RC) and its main active compound, berberine, have either antimicrobial or anti-obesity activities. In the present study, we hypothesize that RC exerts anti-obesity effects that are likely mediated by mechanisms of regulating gut microbes and berberine may be a key compound of RC. Gut microbes and glucose and lipid metabolism in high-fat diet-fed C57BL/6J (HFD) mice in vivo are investigated after RC and berberine treatments. The results show that RC (200 mg/kg) and berberine (200 mg/kg) significantly lower both body and visceral adipose weights, and reduce blood glucose and lipid levels, and decrease degradation of dietary polysaccharides in HFD mice. Both RC and berberine significantly reduce the proportions of fecal Firmicutes and Bacteroidetes to total bacteria in HFD mice. In the trial ex vivo, both RC and berberine significantly inhibit the growth of gut bacteria under aerobic and anaerobic conditions. In in vitro trials, both RC and berberine significantly inhibit the growth of Lactobacillus (a classical type of Firmicutes) under anaerobic conditions. Furthermore, both RC and berberine significantly increase fasting-induced adipose factor (Fiaf, a key protein negatively regulated by intestinal microbes) expressions in either intestinal or visceral adipose tissues. Both RC and berberine significantly increase mRNA expressions of AMPK, PGC1α, UCP2, CPT1α, and Hadhb related to mitochondrial energy metabolism, which may be driven by increased Fiaf expression. These results firstly suggest that antimicrobial activities of RC and berberine may result in decreasing degradation of dietary polysaccharides, lowering potential calorie intake, and then systemically activating Fiaf protein and related gene expressions of mitochondrial energy metabolism in visceral adipose tissues. Taken together, these action mechanisms may contribute to significant anti-obesity effects. Findings in the present study also indicate that pharmacological regulation on gut microbes can develop an anti-obesity strategy.

Effects of palmitic acid on lipid metabolism homeostasis and apoptosis in goose primary hepatocytes

Studies have shown that not only does palmitic acid promote triglyceride (TG) accumulation, but it also affects cell viability in in vitro steatosis models. However, to what degree these effects are mediated by steatosis in goose primary hepatocytes is unknown. In this study, the effects of palmitic acid on the lipid metabolism homeostasis pathway and on apoptosis were determined. The authors measured the mRNA levels of genes involved in TG synthesis, lipid deposition, fatty acid oxidation and the assembly and secretion of VLDL-TG in goose primary hepatocytes. The results indicated that palmitic acid can significantly reduce the activity of goose hepatocytes, and that palmitic acid had a significant effect on TG accumulation; however, with increasing palmitic acid concentrations, the extracellular TG and extracellular VLDL concentration gradually decreased. With increasing palmitic acid concentrations, the gene expression levels of DGAT1, DGAT2, PPARα, CPT-1, FoxO1 and MTTP (which regulate hepatic TG synthesis, fatty acid oxidation and the assembly and secretion of VLDL-TGs) first increased and then decreased; the change in PLIN gene expression was palmitic acid dose-dependent, similar to the regulatory mode of intracellular TG accumulation. In conclusion, this study clearly shows that palmitic acid can promote TG accumulation and induce apoptosis in goose primary hepatocytes, and this effect may be related to the lipid metabolism pathway.

Analysis of transcriptome and metabolome profiles alterations in fatty liver induced by high-fat diet in rat

Excessive energy intake greatly contributes to the development of nonalcoholic fatty liver disease (NAFLD) in modern society. To better understand the comprehensive mechanisms of NAFLD development, we investigated the metabolic alterations of rats with NAFLD induced by high-fat diet (HFD). Male Wistar rats were fed a HFD or standard chow for control. After 16 weeks, rat serum was collected for biochemical measurement. The rats' livers were resected and subjected to histology inspection and gene expression analysis with complementary DNA microarray and metabolic analysis with gas chromatography-mass spectroscopy. In HFD rats, the serum cholesterol, triglycerides, glucose, and insulin contents were increased; and the total cholesterol and triglycerides in the livers were also significantly increased. Complementary DNA microarray analysis revealed that 130 genes were regulated by HFD. Together with real-time reverse transcriptase polymerase chain reaction, lipid metabolism regulatory members like sterol regulatory element binding factor 1 and stearoyl-coenzyme A desaturase 1 had up-regulation, whereas others like peroxisome proliferator-activated receptor, carnitine palmitoyltransferase 1, and 3-hydroxy-3-methylglutaryl-coenzyme A reductase had repressed expression, in HFD rat livers. Metabolomic analysis showed that tetradecanoic acid, hexadecanoic acid, and oleic acid had elevation and arachidonic acid and eicosapentaenoic acid had decreased content in HFD rat livers. Amino acids including glycine, alanine, aspartic acid, glutamic acid, and proline contents were decreased. The integrative results from transcriptomic and metabolomic studies revealed that, in HFD rat livers, fatty acid utilization through beta-oxidation was inhibited and lipogenesis was enhanced. These observations facilitated our understanding of the pathways involved in the development of NAFLD induced by HFD.

Intraperitoneal injections of low doses of C75 elicit a behaviorally specific and vagal afferent-independent inhibition of eating in rats

Central and intraperitoneal C75, an inhibitor of fatty acid synthase and stimulator of carnitine palmitoyl-transferase-1, inhibits eating in mice and rats. Mechanisms involved in feeding inhibition after central C75 have been identified, but little is yet known about how systemic C75 might inhibit eating. One issue is whether intraperitoneal C75 reduces food intake in rats by influencing normal physiological controls of food intake or acts nonselectively, for example by eliciting illness or aversion. Another issue relates to whether intraperitoneal C75 acts centrally or, similar to some other peripheral metabolic controls of eating, activates abdominal vagal afferents to inhibit eating. To further address these questions, we investigated the effects of intraperitoneal C75 on spontaneous meal patterns and the formation of conditioned taste aversion (CTA). We also tested whether the eating inhibitory effect of intraperitoneal C75 is vagally mediated by testing rats after either total subdiaphragmatic vagotomy (TVX) or selective subdiaphragmatic vagal deafferentations (SDA). Intraperitoneal injection of 3.2 and 7.5 mg/kg of C75 significantly reduced food intake 3, 12, and 24 h after injection by reducing the number of meals without affecting meal size, whereas 15 mg/kg of C75 reduced both meal number and meal size. The two smaller doses of C75 failed to induce a CTA, but 15 mg/kg C75 did. The eating inhibitory effect of C75 was not diminished in either TVX or SDA rats. We conclude that intraperitoneal injections of low doses of C75 inhibit eating in a behaviorally specific manner and that this effect does not require abdominal vagal afferents.