Enzyme acetyl-CoA Carboxylase Research Articles

The energy metabolism of the freshwater leech Whitmania pigra in response to fasting

Non-blood-feeding leeches, Whitmania pigra, have evolved unique digestive structures and physiological mechanisms to cope with fasting. However, the metabolic changes and molecular mechanisms induced by fasting remain unclear. Therefore, this study recorded the weights of leeches during the fasting process. The weight changes were divided into two stages: a rapid decline period (1–9 weeks) and a fluctuating decline period (9–24 weeks). Leeches fasted for 4 (H4), 11 (H11), and 24 (H24) weeks were selected for transcriptome sequencing. Compared to the control group (H0), 436, 1157, and 337 differentially expressed genes (DEGs) were identified, which were mainly related to glycolysis/gluconeogenesis, amino acid metabolism, and the lipid metabolism pathway. The 6-phosphofructokinase (Pfk), pyruvate kinase (PK), and phosphoenolpyruvate carboxykinase (Pck) transcription levels revealed glycolysis/gluconeogenesis activation during the early stage of fasting and peaked at 11 weeks. Decreased expression of the rate-limiting enzyme acetyl-CoA carboxylase (ACC) in fatty acid synthesis during fasting may impede fatty acid synthesis. These results indicated that the nutrient storage and energy-supplying pathways in W. pigra were modified to improve fasting resistance. The findings of this study provided guidance for exploring the mechanism underlying fasting metabolism and laid a foundation for artificial breeding to improve the resistance of leeches.

Mechanistic of AMPK/ACC2 regulating myoblast differentiation by fatty acid oxidation of goat

Myoblast differentiation depends on fatty acid oxidation (FAO)，and its rate-limiting enzyme acetyl-CoA carboxylase 2 (ACC2) participate in the regulation skeletal muscle development. However, the precise regulatory mechanism is still unknown. Using previous RNA-sequencing data from our laboratory, we explored the effect of ACC2 on myoblast differentiation, as a candidate gene, since its expression is higher in myoblasts of lamb (first day of age) than that of the fetus (75th day of pregnancy). Our findings show that siACC2 inhibited myoblast proliferation, promoted differentiation, and boosted mitochondrial and fatty acid oxidation activities. The effect of ACC2 on goat muscle cell differentiation was modulated by Etomoxir, a CPT1A inhibitor. Notably, the AMPK/ACC2 pathway was found to regulate fatty acid oxidation and goat muscle cell differentiation. Inhibiting the AMPK/ACC2 pathway significantly reduced CPT1A expression. These findings indicate that AMPK/ACC2 regulate goat myoblast differentiation via fatty acid oxidation, contributing to understanding the mechanism of goat skeletal muscle development.

Difference of effective component content and key enzyme gene expression of biosynthesis in Atractylodes chinensis with different leaf shapes

In this study, four Atractylodes chinensis(A. chinensis) with different leaf shapes, such as the split leaf, long and narrow leaf, oval leaf, and large round leaf, were used as experimental materials to establish a method for simultaneously determining atractylodin, atractylenolide Ⅰ, β-eudesmol, and atractylon in the rhizome of A. chinensis. The expression of key enzyme genes for biosynthesis of acetyl-CoA carboxylase(ACC), 3-hydroxy-3-methylglutaryl-CoA reductase(HMGR), and farnesyl pyrophosphate synthase(FPPS) was detected by real-time fluorescence quantitative polymerase chain reaction(qRT-PCR). High performance liquid chromatography(HPLC) was used to compare the difference in the content of four active components in A. chinensis with different leaf shapes, and the correlation between the content of active components and the expression of key enzyme genes in biosynthesis was discussed. The results show that there was good linearity among atractylodin, atractylenolide Ⅰ, β-eudesmol, and atractylon in the range of 3.30-33.00 μg·mL~(-1)(r =0.999 7), 12.04-120.40 μg·mL~(-1)(r =0.999 5), 29.16-291.60 μg·mL~(-1)(r =0.999 5), and 14.20-142.00 μg·mL~(-1)(r =0.999 5), respectively. The average recoveries were 99.77%(RSD=2.1%), 98.56%(RSD=1.2%), 103.0%(RSD=1.2%), and 100.6%(RSD=1.5%), respectively. The method was accurate and had good reproducibility, which could be used to simultaneously detect atractylodin, atractylenolide Ⅰ, β-eudesmol, and atractylon. The results showed that there were significant differences in the content of four active components in A. chinensis with different leaf shapes. The content of atractylodin, atractylenolide Ⅰ, and β-eudesmol in A. chinensis with split leaves was the highest, which were 1.341 9, 5.237 2, and 12.084 3 mg·g~(-1), respectively. The content of atractylon in A. chinensis with long and narrow leaves was the highest(5.470 1 mg·g~(-1)). The content of atractylodin, atractylenolide Ⅰ, β-eudesmol, and atractylon in A. chinensis with oval leaves was the lowest. The total content of the four effective components in descending order was A. chinensis with split leaves > A. chinensis with long and narrow leaves > A. chinensis with large round leaves > A. chinensis with oval leaves. The gene expression levels of key enzymes ACC, HMGR, and FPPS in A. chinensis with split leaves were the highest(P < 0.05), and the gene expression levels of key enzymes ACC and HMGR in A. chinensis with oval leaves were the lowest(P < 0.05). The gene expression level of key enzyme FPPS in A. chinensis with large round leaves was the lowest. In A. chinensis with different leaf shapes, the key enzyme gene ACC was significantly positively correlated with the polyacetylene component, namely atractylodin(P < 0.01), and the key enzyme genes HMGR and FPPS were positively correlated with the sesquiterpene components, namely atractylenolide Ⅰ, β-eudesmol, and atractylon. In summary, the quality of A. chinensis with split leaves is the best, and the biosynthesis of atractylodin is significantly correlated with the gene expression of key enzyme ACC, which provides a theoretical basis for screening and optimizing the germplasm resources of A. chinensis and improving the quality of medicinal materials.

Abstract 1783: Understanding lipogenesis in bladder cancer

Abstract Cancer cells are known to have different metabolic needs for growth and survival and by understanding these demands of individual cancers, targeted novel therapies may be developed. Lipogenesis and ß-oxidation serve to balance lipid levels in the cell. Lipogenesis is rate limited by a series of reactions that include enzymes fatty acid synthase (FASN) and acetyl-CoA carboxylase (ACC1) that facilitate lipid formation; whereas ß-oxidation is rate limited by the transporter carnitine palmitoyltransferase 1 (CPT1) and the enzyme thiolase that catalyzes the final step of the ß-oxidation cycle. Many cancers are dependent on lipogenesis, but the role of these factors in BCa is poorly defined. The Cancer Genome Atlas was used to assess levels of relevant metabolic proteins in normal and cancerous BCa tissue, and showed FASN levels were elevated in BCa tissue and were associated with worse survival. The purpose of this project is to better understand the metabolic demands of bladder cancer (BCa) cell lines, and we hypothesized lipogenesis is a major metabolic pathway for BCa cell growth. T24, HTB-5, and HTB-9 BCa cell lines were used to evaluate the role of metabolism. CPT1 was inhibited with etomoxir, thiolase with trimetazidine, FASN with cerulenin, and ACC1 with 5-(Tetradecyloxy)-2-furoic acid (TOFA). Cell viability was assessed at 48 and 72 hours with an enzymatic activity assay measuring ß-hexosaminidase activity as a surrogate for cell proliferation. The IC50 (concentration of a drug to reduce cell proliferation by 50%) was calculated from this data. At 48 hours, cerulenin-treated cells had an IC50 of 11.80 µM, 13.28 µM, 18.31 µM for HTB-9, T24, and HTB-5 respectively. At 48 hours, TOFA-treated cells had an IC50 of 64.25 µM, 59.29 µM, 32.03 µM for HTB-9, T24, and HTB-5 respectively. Cellular proliferation was not inhibited by CPT1 or trimetazidine at enzymatic IC50 concentrations consistent with their known levels of efficacy. When adding the lipid palmitate (20µM) to TOFA-treated cells, it appeared to mediate a rescue of cell proliferation almost to control, although statistical significance was not achieved. Crystal violet assays were performed to assess long-term cell viability. There was visible reduction in colony formation in a dose-dependent manner at 5 µM and 10 µM cerulenin in T24 cells at 14 days of culture, and there were similar results in HTB-9 cells treated with 20 µM and 40 µM TOFA at 17 days. In both cerulenin and TOFA-treated cells, there was elevated cleaved caspase-3 protein expression, indicating initiation of apoptosis. In conclusion, inhibition of lipogenesis in BCa cell lines reduces cell viability by reducing proliferation and inducing apoptosis whereas inhibitors of ß-oxidation did not produce the same effect at relevant concentrations. These data indicate lipogenesis is a key metabolic pathway for BCa cell growth. Citation Format: Juliann Leak, David Matye, Erika Abbott, Benjamin Woolbright, John A. Taylor. Understanding lipogenesis in bladder cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1783.

Facile adipocyte uptake and liver/adipose tissue delivery of conjugated linoleic acid-loaded tocol nanocarriers for a synergistic anti-adipogenesis effect

Obesity is a major risk to human health. Adipogenesis is blocked by α-tocopherol and conjugated linoleic acid (CLA). However, their effect at preventing obesity is uncertain. The effectiveness of the bioactive agents is associated with their delivery method. Herein, we designed CLA-loaded tocol nanostructured lipid carriers (NLCs) for enhancing the anti-adipogenic activity of α-tocopherol and CLA. Adipogenesis inhibition by the nanocarriers was examined using an in vitro adipocyte model and an in vivo rat model fed a high fat diet (HFD). The targeting of the tocol NLCs into adipocytes and adipose tissues were also investigated. A synergistic anti-adipogenesis effect was observed for the combination of free α-tocopherol and CLA. Nanoparticles with different amounts of solid lipid were developed with an average size of 121‒151 nm. The NLCs with the smallest size (121 nm) showed greater adipocyte internalization and differentiation prevention than the larger size. The small-sized NLCs promoted CLA delivery into adipocytes by 5.5-fold as compared to free control. The nanocarriers reduced fat accumulation in adipocytes by counteracting the expression of the adipogenic transcription factors peroxisome proliferator activated receptor (PPAR)γ and CCAAT/enhancer-binding protein (C/EBP)α, and lipogenic enzymes acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS). Localized administration of CLA-loaded tocol NLCs significantly reduced body weight, total cholesterol, and liver damage indicators in obese rats. The biodistribution study demonstrated that the nanoparticles mainly accumulated in liver and adipose tissues. The NLCs decreased adipocyte hypertrophy and cytokine overexpression in the groin and epididymis to a greater degree than the combination of free α-tocopherol and CLA. In conclusion, the lipid-based nanocarriers were verified to inhibit adipogenesis in an efficient and safe way.

Physiology and Mechanism of Milk Fat Globules Secretion in Dairy Animals: A Review

Milk fat globules (MFGs) are a complex compound secreted in the mammary gland, composed of triglycerides; phosphatidylethanolamine (PE) phosphatidylcholine (PC) with unclear mechanism and the fused lipid droplets enclosed by inner layer derived from the endoplasmic reticulum and outer bilayer is directly derived from the apical plasma membrane as the lipid droplets bud out from the cell. The core components of MFGs, triglycerides are synthesized via the de novo fatty acid pathway and LCFA was directly taken from serum. The de novo fatty acid pathway was significantly dependent on the enzymes acetyl-CoA carboxylase (ACACA), fatty acid synthase (FASN) and acyl-CoA synthetase short-chain family member 2 (ACSS2) to synthesize short and medium-chain fatty acids, whereas the bio-hydrogenation pathway is a principal pathway for the synthesis of long-chain fatty acids. Following this, the milk fat globules coated by the membrane are released from the MEC to the lumen with or without other milk components and the membrane that surrounds the fat globule stabilize the milk fat in its dispersed state, prevent flocculation and globule coalescence, and protects against the deleterious effects of lipases. Even though the secretion mechanism of lipid droplets is controversial hormonal and molecular mechanisms are involved. Moreover, the fat globule size and composition are determined by factors such as stage of lactation, physiological state of the animal, Diacylglycerol Acyltransferase1 (DGAT1) activity, and PC/PE ratio along with breed and animal species. While some studies were conducted on milk synthesis and secretion, the molecular mechanism behind lipid droplet fusion, secretion in the apical membrane and how MFGM is formed and the mechanism of MFG synthesis regulation are undiscovered. Therefore, it needs advanced investigation.

Gibberellic acid (GA) role in acetyl-coA carboxylase enzyme regulation and in improving oil palm yield

Seaweed specifically, Sargassum sp. is known to contains a boosting hormone growth that has been promoted plant growth and yield due to the containing of auxin, gibberelic acid (GA) and cytokinine, and also some amino acids especially glutamic acid. Those composition could be used as an booster of palm oil production which related to acetyl co-A carboxylase activity (ACC). ACC is the rate determination step in fatty acid accumulation, and becomes active through dephosphorylation of some serine residues that induced by magnesium and glutamate. Moreover, ACC was regulated by AtWRI1 and AtWRI1-TCP4 interaction, a mechanism that allow fine-tuning of the oil biosynthetic pathway. In this research we conducted gene expression experiments, and molecular docking analyses to study the possible mechanism of seaweed composition stimulating oil accumulation in the oil palm. Further analysis was conducted to ensure whether the interaction between TCP4 and candidate inhibitors were able to phosphorylate TCP4 and decrease its activity. GA application resulted in the increase of oil accumulation in 1 month after application, although in the second month the oil accumulation showed decreasing. Increase of oil accumulation in the first month in line with the increase of the expression of ACC in 3rd and 5th weeks. Meanwhile, TCP4 showed decrease expression that resulted in the increase of the WRI1 in 5th week. From this result, it was indicated that GA application could block the TCP4, so it could not interact with WRI1, resulted in the expression of WRI1 and ACC. This interaction stimulates the oil accumulation in oil palm.

Gibberellic acid (GA) role in acetyl-coA carboxylase enzyme regulation and in improving oil palm yield

Seaweed specifically, Sargassum sp. is known to contains a boosting hormone growth that has been promoted plant growth and yield due to the containing of auxin, gibberelic acid (GA) and cytokinine, and also some amino acids especially glutamic acid. Those composition could be used as an booster of palm oil production which related to acetyl co-A carboxylase activity (ACC). ACC is the rate determination step in fatty acid accumulation, and becomes active through dephosphorylation of some serine residues that induced by magnesium and glutamate. Moreover, ACC was regulated by AtWRI1 and AtWRI1-TCP4 interaction, a mechanism that allow fine-tuning of the oil biosynthetic pathway. In this research we conducted gene expression experiments, and molecular docking analyses to study the possible mechanism of seaweed composition stimulating oil accumulation in the oil palm. Further analysis was conducted to ensure whether the interaction between TCP4 and candidate inhibitors were able to phosphorylate TCP4 and decrease its activity. GA application resulted in the increase of oil accumulation in 1 month after application, although in the second month the oil accumulation showed decreasing. Increase of oil accumulation in the first month in line with the increase of the expression of ACC in 3rd and 5th weeks. Meanwhile, TCP4 showed decrease expression that resulted in the increase of the WRI1 in 5th week. From this result, it was indicated that GA application could block the TCP4, so it could not interact with WRI1, resulted in the expression of WRI1 and ACC. This interaction stimulates the oil accumulation in oil palm.

Immature Persimmon (Diospyros kaki Thunb.) Ethanol Extract Ameliorates High-Fat Diet-Induced Obesity by Modulating Lipid Metabolism.

In this study, immature persimmon (Diospyros kaki Thunb.) ethanol extract was administered to an obese animal model fed a high-fat diet to measure weight change, adipose tissue weight, serum lipid level, and expression level of adipose-related genes to evaluate its efficacy. Administration of D. kaki ethanol extract (DKE) (100 and 500 mg/kg/d) decreased the body weight gain, adipose tissue weight, and serum triglyceride levels in mice fed a high-fat diet. Furthermore, it improved the leptin and adiponectin levels in the blood as well as gene expression in the liver. It also inhibited the expression of sterol regulatory element-binding protein-1c, inhibiting the production of triglyceride biosynthetic enzyme fatty acid synthesis and acetyl-CoA carboxylase, and decreased the expressions of peroxisome proliferator-activated receptor γ and CCAAT/enhancer-binding proteins that induce adipocyte differentiation. Therefore, these data suggest that DKE exerts beneficial effects on high-fat diet-induced obesity by modulating lipid metabolism in mice fed a high-fat diet.

Supply of palmitic, stearic, and oleic acid changes rumen fiber digestibility and microbial composition

The concept that fat supplementation impairs total-tract fiber digestibility in ruminants has been widely accepted over the past decades. Nevertheless, the recent interest in the dietary fatty acid profile to dairy cows enlightened the possible beneficial effect of specific fatty acids (e.g., palmitic, stearic, and oleic acids) on total-tract fiber digestibility. Because palmitic, stearic, and oleic acids are the main fatty acids present in ruminal bacterial cells, we hypothesize that the dietary supply of these fatty acids will favor their incorporation into the bacterial cell membranes, which will support the growth and enrichment of fiber-digesting bacteria in the rumen. Our objective in this experiment was to investigate how dietary supply of palmitic, stearic, and oleic acid affect fiber digestion, bacterial membrane fatty acid profile, microbial growth, and composition of the rumen bacterial community. Diets were randomly assigned to 8 single-flow continuous culture fermenters arranged in a replicated 4 × 4 Latin square with four 11-d experimental periods. Treatments were (1) a control basal diet without supplemental fatty acids (CON); (2) the control diet plus palmitic acid (PA); (3) the control diet plus stearic acid (SA); and (4) the control diet plus oleic acid (OA). All fatty acid treatments were included in the diet at 1.5% of the diet (dry matter [DM] basis). The basal diet contained 50% orchardgrass hay and 50% concentrate (DM basis) and was supplied at a rate of 60 g of DM/d in 2 equal daily offers (0800 and 1600 h). Data were analyzed using a mixed model considering treatments as fixed effect and period and fermenter as random effects. Our results indicate that PA increased in vitro fiber digestibility by 6 percentage units compared with the CON, while SA had no effect and OA decreased fiber digestibility by 8 percentage units. Oleic acid decreased protein expression of the enzymes acetyl-CoA carboxylase compared with CON and PA, while fatty acid synthase was reduced by PA, SA, and OA. We observed that PA, but not SA or OA, altered the bacterial community composition by enhancing bacterial groups responsible for fiber digestion. Although the dietary fatty acids did not affect the total lipid content and the phospholipid fraction in the bacterial cell, PA increased the flow of anteiso C13:0 and anteiso C15:0 in the phospholipidic membrane compared to the other treatments. In addition, OA increased the flow of C18:1 cis-9 and decreased C18:2 cis-9,cis-12 in the bacterial phospholipidic membranes compared to the other treatments. Palmitic acid tended to increase bacterial growth compared to other treatments, whereas SA and OA did not affect bacterial growth compared with CON. To our knowledge, this is the first research providing evidence that palmitic acid supports ruminal fiber digestion through shifts in bacterial fatty acid metabolism that result in changes in growth and abundance of fiber-degrading bacteria in the microbial community.

Effect of carbon and nitrogen concentrations on lipid accumulation and regulation of acetyl-CoA carboxylase in Papiliotrema laurentii.

Biodiesel is an interesting alternative to petroleum diesel as it is renewable, biodegradable, and has a low pollutant content. Yeast oils can be used for biodiesel production instead of edible oils, mitigating the use of arable land and water for biodiesel production. Maximum lipid accumulation is reached at 48h of cultivation by the oleaginous yeast Papiliotrema laurentii UFV-1. Nevertheless, the effects of carbon and nitrogen concentrations on lipid accumulation, as well as the regulation of lipid metabolism in this yeast are still not well-characterised. Therefore, this work evaluated the effects of carbon and nitrogen concentrations on the lipid accumulation in P. laurentti, the expression of the ACC gene, and the activity of the enzyme acetyl-CoA carboxylase (ACCase) in different carbon:nitrogen ratios (C:N) and glucose concentrations. The variation of ammonium sulfate concentration did not affect the growth and lipid accumulation in P. laurentii UFV-1. On the other hand, glucose concentration remarkably influenced biomass and lipid production by this yeast. Therefore, the carbon concentration is more important than the nitrogen concentration for lipid production by P. laurentii UFV-1. Importantly, the levels of both ACC gene expression and ACCase activity were maximum during the late-exponential growth phase and decreased after reaching the highest lipid contents, which was easier evidenced during the accumulation and maximum lipid levels. As such, the reduction of ACCase enzyme activity seems to be related to the decrease in the expression level of the ACC gene.

Fatty acid synthesis and oxidation regulate human endoderm differentiation by mediating SMAD3 nuclear localization via acetylation.

Metabolic remodeling is one of the earliest events that occur during cell differentiation. Here, we define fatty acid metabolism as a key player in definitive endoderm differentiation from human embryonic stem cells. Fatty acid β-oxidation is enhanced while lipogenesis is decreased, and this is due to the phosphorylation of lipogenic enzyme acetyl-CoA carboxylase by AMPK. More importantly, inhibition of fatty acid synthesis by either its inhibitors or AMPK agonist significantly promotes human endoderm differentiation, while blockade of fatty acid oxidation impairs differentiation. Mechanistically, reduced de novo fatty acid synthesis and enhanced fatty acid β-oxidation both contribute to the accumulation of intracellular acetyl-CoA, which guarantees the acetylation of SMAD3 and further causes nuclear localization to promote endoderm differentiation. Thus, our current study identifies a fatty acid synthesis/oxidation shift during early differentiation and presents an instructive role for fatty acid metabolism in regulating human endoderm differentiation.

Abstract P3029: The Role Of Fatty Acid Synthase In The Modulation Of Vascular Smooth Muscle Cells Into A Foam Cell Phenotype

Background: The contractile phenotype of differentiated VSMCs is essential for vascular function. When exposed to Cholesterol (CHO), VSMCs dedifferentiate and acquire characteristics of foam cells, lipid-laden macrophage-like cells that comprise the Atherosclerotic plaques. CHO uptake by VSMCs is either removed by ABCA1-mediated efflux or is stored in lipid droplets as cholesterol esters (CEs). CEs are formed by the reaction of CHO with fatty acids catalyzed by SOAT1. Thus, we hypothesize that fatty acid biosynthesis controls the formation of VSMC-derived foam cells. Results: In VSMCs, CHO treatment upregulates the lipogenic enzymes FASN (3.6±1 vs. 9.0±0.9 AU p<0.01) and acetyl-CoA carboxylase (ACC) (2.8±0.5 vs. 10.2±2.3 AU p=0.02) and induces the phosphorylation of ATP Citrate Lyase (ACLY) (1.4±0 vs. 6.2±1 AU). Consistent with the literature, these changes are accompanied by increased expression of the macrophage-related markers CD68 and KLF4. Significantly, downregulation of FASN inhibits the CHO-induced CD68 (9.1±0.8 vs. 4.6±1,9 p=0.002) and KLF4 (p=0.02) expression upregulation. FASN-deficient VSMCs failed to accumulate lipids and transition to a foam cell phenotype after CHO treatment measured by Oil Red O staining. Interestingly, FASN-deficient VSMCs have decreased expression of SOAT1 (p=0.04) and increased expression of the CHO efflux transporter ABCA1 (p=0.04). Conclusion: Our study shows lipogenic enzymes are upregulated during the VSMC to foam cell transition triggered by CHO treatment. FASN expression is required for VSMC-derived foam cell formation. Our data suggest that FASN participates in the esterification of CHO and foam cell formation and may contribute to atherosclerotic plaque accumulation. Thus, FASN may represent a novel target for therapeutic intervention.

Alterations of hepatic energy metabolism in murine models of obesity, diabetes and fatty liver diseases.

Disturbed hepatic energy metabolism contributes to non-alcoholic fatty liver (NAFLD), but the development of changes over time and obesity- or diabetes-related mechanisms remained unclear. Two-day old male C57BL/6j mice received streptozotocin (STZ) or placebo (PLC) and then high-fat (HFD) or regular chow diet (RCD) from week 4 (W4) to either W8 or W16, yielding control [CTRL=PLC+RCD], diabetes [DIAB=STZ+RCD], obesity [OBES=PLC+HFD] and diabetes-related non-alcoholic steatohepatitis [NASH=STZ+HFD] models. Mitochondrial respiration was measured by high-resolution respirometry and insulin-sensitive glucose metabolism by hyperinsulinemic-euglycemic clamps with stable isotope dilution. NASH showed higher steatosis and NAFLD activity already at W8 and liver fibrosis at W16 (all p<0.01 vs CTRL). Ballooning was increased in DIAB and NASH at W16 (p<0.01 vs CTRL). At W16, insulin sensitivity was 47%, 58% and 75% lower in DIAB, NASH and OBES (p<0.001 vs CTRL). Hepatic uncoupled fatty acid oxidation (FAO)-associated respiration was reduced in OBES at W8, but doubled in DIAB and NASH at W16 (p<0.01 vs CTRL) and correlated with biomarkers of unfolded protein response (UPR), oxidative stress and hepatic expression of certain enzymes (acetyl-CoA carboxylase 2, Acc2; carnitine palmitoyltransferase I, Cpt1a). Tricarboxylic acid cycle (TCA)-driven respiration was lower in OBES at W8 and doubled in DIAB at W16 (p<0.0001 vs CTRL), which positively correlated with expression of genes related to lipolysis. Hepatic mitochondria adapt to various metabolic challenges with increasing FAO-driven respiration, which is linked to dysfunctional UPR, systemic oxidative stress, insulin resistance and altered lipid metabolism. In a diabetes model, higher TCA-linked respiration reflected mitochondrial adaptation to greater hepatic lipid turnover. Funding bodies that contributed to this study were listed in the acknowledgements section.

Effect of selinexor on lipogenesis in virus-positive Merkel cell carcinoma cell lines.

Merkel cell carcinoma (MCC) is a highly aggressive neuroendocrine cutaneous carcinoma aetiologically linked to the Merkel cell polyomavirus (MCPyV). Immune checkpoint inhibitors are currently the first-line therapy for metastatic MCC; however, the treatment is effective in only about half of patients, highlighting the need for alternative therapies. Selinexor (KPT-330) is a selective inhibitor of nuclear exportin 1 (XPO1) and has been shown to inhibit MCC cell growth in vitro, but the pathogenesis has not been established. Decades of research have established that cancer cells significantly upregulate lipogenesis to meet an increased demand for fatty acids and cholesterol. Treatments that inhibit lipogenic pathways may halt cancer cell proliferation. To determine the effect of increasing doses of selinexor on fatty acid and cholesterol synthesis in MCPyV-positive MCC (MCCP) cell lines and aid in elucidating the mechanism by which selinexor prevents and reduces MCC growth. MKL-1 and MS-1 cell lines were treated with increasing doses of selinexor for 72 h. Protein expression quantification was determined using chemiluminescent Western immunoblotting and densitometric analysis. Fatty acids and cholesterol were quantified using free fatty acid assay and cholesterol ester detection kits. Selinexor causes statistically significant reductions of the lipogenic transcription factors sterol regulatory element-binding proteins 1 and 2, and lipogenic enzymes acetyl-CoA carboxylase, fatty acid synthase, squalene synthase and 3β-hydroxysterol Δ-24-reductase in a dose-dependent manner in two MCCP cell lines. Although inhibiting the fatty acid synthesis pathway results in meaningful decreases in fatty acids, the cellular cholesterol levels did not demonstrate such reductions. For patients with metastatic MCC refractory to immune checkpoint inhibitors, selinexor may provide clinical benefit through the inhibition of the lipogenesis pathway; however, further research and clinical trials are needed to evaluate these findings.

Lithium Chloride Promotes Endogenous Synthesis of CLA in Bovine Mammary Epithelial Cells.

Although conjugated linoleic acid (CLA) can promote human health, its content in milk is insufficient to have a significant impact. The majority of the CLA in milk is produced endogenously by the mammary gland. However, research on improving its content through nutrient-induced endogenous synthesis is relatively scarce. Previous research found that the key enzyme, stearoyl-CoA desaturase (SCD) for the synthesis of CLA, can be expressed more actively in bovine mammary epithelial cells (MAC-T) when lithium chloride (LiCl) is present. This study investigated whether LiCl can encourage CLA synthesis in MAC-T cells. The results showed that LiCl effectively increased SCD and proteasome α5 subunit (PSMA5) protein expression in MAC-T cells as well as the content of CLA and its endogenous synthesis index. LiCl enhanced the expression of proliferator-activated receptor-γ (PPARγ), sterol regulatory element-binding protein 1 (SREBP1), and its downstream enzymes acetyl CoA carboxylase (ACC), fatty acid synthase (FASN), lipoprotein lipase (LPL), and Perilipin 2 (PLIN2). The addition of LiCl significantly enhanced p-GSK-3β, β-catenin, p-β-catenin protein expression, hypoxia-inducible factor-1α (HIF-1α), and downregulation factor genes for mRNA expression (P < 0.05). These findings highlight that LiCl can increase the expression of SCD and PSMA5 by activating the transcription of HIF-1α, Wnt/β-catenin, and the SREBP1 signaling pathways to promote the conversion of trans-vaccenic acid (TVA) to the endogenous synthesis of CLA. This data suggests that the exogenous addition of nutrients can increase CLA content in milk through pertinent signaling pathways.

Identification of acetyl-CoA carboxylase alpha as a prognostic and targeted candidate for hepatocellular carcinoma.

The de novo lipogenesis has been a longstanding observation in hepatocellular carcinoma (HCC). However, the prognostic value and carcinogenic roles of the enzyme Acetyl-CoA carboxylase alpha (ACACA) in HCC remains unknown. The proteins with remarkable prognostic significance were screened out from The Cancer Proteome Atlas Portal (TCPA) database. Furthermore, the expression characteristics and prognostic value of ACACA were evaluated in multiple databases and the local HCC cohort. The loss-of-function assays were performed to uncover the potential roles of ACACA in steering malignant behaviors of HCC cells. The underlying mechanisms were conjectured by bioinformatics and validated in HCC cell lines. ACACA was identified as a crucial factor of HCC prognosis. Bioinformatics analyses showed that HCC patients with higher expression of ACACA protein or mRNA levels had poor prognosis. Knockdown of ACACA remarkably crippled the proliferation, colony formation, migration, invasion, epithelial-mesenchymal transition (EMT) process of HCC cells and induced the cell cycle arrest. Mechanistically, ACACA might facilitate the malignant phenotypes of HCC through aberrant activation of Wnt/β-catenin signaling pathway. In addition, ACACA expression was associated with the dilute infiltration of immune cells including plasmacytoid DC (pDC) and cytotoxic cells by utilization of relevant database analysis. ACACA could be a potential biomarker and molecular target for HCC.

Effect of Zilpaterol Hydrochloride and Zinc Methionine on Growth, Carcass Traits, Meat Quality, Fatty Acid Profile and Gene Expression in Longissimus dorsi Muscle of Sheep in Intensive Fattening

Zilpaterol hydrochloride (ZH) redistributes ingested energy and improves feed efficiency by increasing muscle mass and reducing fat in sheep and cattle carcasses in fattening; however, by increasing lipolysis and reducing intramuscular fat (IMF), it can affect meat quality in terms of the attributes of tenderness, juiciness, taste and color; in contrast, Zn methionine (ZM), due to its lipogenic effect, can improve meat marbling without affecting production efficiency. In the current study, 36 male Suffolk sheep were used (25 ± 0.58 kg live weight, LW) to evaluate the supply of ZH and ZM on growth, carcass traits, meat quality, fatty acid content and expression of genes which regulate the deposition of fatty acids (FA) in IMF. A completely randomized design was used, with factorial arrangement of 2 × 2 ZH (0 and 0.2 mg kg−1 LW) and ZM (0 and 80 mg Zn kg−1 dry matter, DM). The results showed that ZH increased (p &lt; 0.05) carcass yield, compactness index and chop eye area and decreased greasing (p &lt; 0.02). The content of ether extract in meat increased (p &lt; 0.05) in sheep with ZM plus ZH, and in sheep with ZM (p &lt; 0.01). ZH (p &lt; 0.05) reduced (p &lt; 0.02) the meat’s color index L*, a*, b*, C* and H*. The content in IMF of stearic (C18:0) and arachidic (C20:0) FA was reduced (p ≤ 0.05) by the effect of ZH, but the palmitoleic (C16:1), eicosatetraenoic (C20:4n6) and conjugated linoleic FA were increased (p ≤ 0.05) by the effect of ZH. ZM increased (p ≤ 0.05) palmitoleic (C16:1) and conjugated linoleic FA; the ZH interaction with ZM increased (p ≤ 0.05) linoleic (C18:2 c 9 c 12), linolenic (C18:3 c 9c12c15) and eicosatetraenoic (C20:4n6) FA. The ZH interaction with ZM influenced (p ≤ 0.05) the total saturated fatty acids (SFA), unsaturated fatty acids (UFA) and polyunsaturated fatty acids (PFA). ZH increased (p ≤ 0.05) the relative expression of mRNA from the enzymes lipoprotein lipase (LPL), hormone-sensitive lipase (HSL), glycerol -3-phosphate acyltransferase (GPAT1) and diglyceride acyltransferase (DGAT1). ZM increased (p ≤ 0.05) the relative expression of mRNA from the enzyme gene acetyl-CoA carboxylase (ACC) and HSL, monoglyceride lipase (MGL). The ZM interaction with ZH increased (p ≤ 0.05) the relative expression of mRNA genes of the enzymes HSL and ACC. It was concluded that ZH improved feed conversion (FC), increased yield and reduced fat in carcasses; ZM increased IMF in Longissimus dorsi. ZH and ZM influenced the FA composition, reduced the SFA and increased the UFA and PFA; both additives also influenced the relative mRNA expression of genes involved in fatty acid metabolism.

ATP-citrate lyase inhibitor improves ectopic lipid accumulation in the kidney in a db/db mouse model.

We evaluated a novel treatment for obesity-related renal, an ATP-citrate lyase (ACL) inhibitor, to attenuate ectopic lipid accumulation (ELA) in the kidney and the ensuing inflammation. An ACL inhibitor was administered intragastrically to 12-week-old db/db mice for 30 days. The appearance of ELA was observed by staining kidney sections with Oil Red O, and the differences in tissue lipid metabolites were assessed by mass spectrometry. The anti-obesity and renoprotection effects of ACL inhibitors were observed by histological examination and multiple biochemical assays. Using the AutoDock Vina application, we determined that among the four known ACL inhibitors (SB-204990, ETC-1002, NDI-091143, and BMS-303141), BMS-303141 had the highest affinity for ACL and reduced ACL expression in the kidneys of db/db mice. We reported that BMS-303141 administration could decrease the levels of serum lipid and renal lipogenic enzymes acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), HMG-CoA reductase (HMGCR), and diminish renal ELA in db/db mice. In addition, we found that reducing ELA improved renal injuries, inflammation, and tubulointerstitial fibrosis. ACL inhibitor BMS-303141 protects against obesity-related renal injuries.

β-1,4-Galactan suppresses lipid synthesis in sebaceous gland cells via TLR4.

Sebum is a lipid mixture secreted from sebaceous glands of the skin. The excessive secretion of sebum causes acne vulgaris and seborrheic dermatitis, while its deficiency causes xerosis. Therefore, the appropriate control of sebum secretion is crucially important to keep the skin healthy. In the present study, we evaluated the effects of naturally occurring polysaccharides on lipid biosynthesis in hamster sebaceous gland cells. Among the tested polysaccharides, β-1,4-galactan, the main chain of type I arabinogalactan, most potently suppressed lipid synthesis in the sebaceous gland cells as analysed by oil red O staining. Toll-like receptor (TLR)4 inhibitors counteracted this suppressive effect and lipopolysaccharide, a TLR4 ligand, mimicked this effect, suggesting the involvement of the TLR4 signalling pathway. In the cells β-1,4-galactan significantly decreased mRNA levels of lipogenesis-related transcription factors (peroxisomeGraphical Abstract$\includegraphics{\bwartpath }$ proliferator-activated receptor γ and sterol regulatory element-binding protein 1) and enzymes (acetyl-CoA carboxylase and fatty acid synthase) as well as the glucose transporter GLUT4. Furthermore, β-1,4-galactan increased the production of lactic acid serving as a natural moisturizing factor and enhanced the proliferation of sebaceous gland cells. These results suggest potential of β-1,4-galactan as a material with therapeutic and cosmetic values for the skin.