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The core clock gene Period2 (PER2) is associated with mammary gland development and lipid synthesis in rodents and has recently been found to have a diurnal variation in the process of lactation, but has not yet been demonstrated in bovine mammary epithelial cells (BMECs). To explore the regulatory function of PER2 on milk fat synthesis in bovine mammary epithelial cells, we initially assessed the expression of clock genes and milk fat metabolism genes for 24 h using real-time quantitative PCR and fitted the data to a cosine function curve. Subsequently, we overexpressed the PER2 in BMECs using plasmid vector (pcDNA3.1-PER2), with empty vector pcDNA3.1-myc as the control. After transfecting BMECs for 48 h, we assessed the protein abundance related to milk fat synthesis by Western blot, the expression of genes coding for these proteins using real time-quantitative PCR, the production of triacylglycerol, and the fatty acid profile. The findings indicated that a total of nine clock genes ( PER1/2 , CRY1/2 , REV-ERBα , BMAL1 , NCOR1 , NR2F2 , FBXW11 ), seven fatty acid metabolism genes ( CD36 , ACSS2 , ACACA , SCD , FADS1 , DGAT1 , ADFP ), and six nuclear receptor-related genes ( INSIG1 , SCAP , SREBF1 , C/EBP , PPARG , LXR ) exhibited oscillation with a period close to 24 h in non-transfected BMECs (R 2 ≥ 0.7). Compared to the control group (transfected with empty pcDNA3.1-myc), the triglyceride content significantly increased in the PER2 overexpression group ( p < 0.05). The lipogenic genes for fatty acid transport and triglyceride synthesis ( ACACA , SCD , LPIN1 , DGAT1 , and SREBF1 ) were upregulated after PER2 overexpression, along with the upregulation of related protein abundance ( p < 0.05). The contents and ratios of palmitic acid (C16:0), oleic acid (C18:1n9c), and trans-oleic acid (C18:1n9t) were significantly increased in the overexpression group ( p < 0.05). Overall, the data supported that PER2 participated in the process of milk fat metabolism and is potentially involved in the de novo synthesis and desaturation of fatty acid in bovine mammary epithelial cells.

Enhanced synthesis or uptake of lipids contributes to rapid cancer cell proliferation and tumor progression. In recent years, cell cycle regulators have been shown to be involved in the control of lipid synthesis, in addition to their classical function of controlling the cell cycle. Clear cell renal cell carcinoma (ccRCC) is the most common subtype of kidney cancer and is characterized by lipid-rich cytoplasmic deposition. However, the relationship between altered lipid metabolism and tumor progression in ccRCC is poorly understood. Here, we demonstrated that E2F transcription factor 1 (E2F1), in addition to its key role in regulating the cell cycle, induces extensive lipid accumulation and elevated levels of lipogenic enzymes in ccRCC cells by upregulating sterol regulatory element-binding protein 1 (SREBP1). E2F1 knockdown or SREBP1 suppression attenuated fatty acid (FA) de novo synthesis, cell proliferation and epithelial-mesenchymal transition (EMT) in ccRCC cells. Furthermore, overexpression of E2F1 promoted lipid storage, tumor growth and metastasis in a mouse xenograft model, whereas E2F1 downregulation or SREBP1 inhibition reversed these effects. In ccRCC patients, high levels of E2F1 and SREBP1 were associated with increased lipid accumulation and correlated with poor prognosis. Our results demonstrate that E2F1 can increase proliferation and metastasis through SREBP1-induced aberrant lipid metabolism, which is a novel critical signaling mechanism driving human ccRCC progression., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Elongation of very long-chain fatty acid (Elovl) proteins are key enzymes that catalyze the rate-limiting step in the fatty acid elongation pathway. The most recently discovered member of the Elovl family, Elovl8, has been proposed to be a fish-specific elongase with two gene paralogs described in teleosts. However, the biological functions of Elovl8 are still to be elucidated. In this study, we showed that in contrast to previous findings, elovl8 is not unique to teleosts, but displays a rather unique and ample phylogenetic distribution. For functional determination, we generated elovl8a ( elovl8a - / - ) and elovl8b ) zebrafish using CRISPR/Cas9 technology. Fatty acid composition in vivo and zebrafish liver cell experiments suggest that the substrate preference of Elovl8 overlapped with other existing Elovl enzymes. Zebrafish Elovl8a could elongate the polyunsaturated fatty acids (PUFAs) C18:2n-6 and C18:3n-3 to C20:2n-6 and C20:3n-3, respectively. Along with PUFA, zebrafish Elovl8b also showed the capacity to elongate C18:0 and C20:1. Gene expression quantification suggests that Elovl8a and Elovl8b may play a potentially important role in fatty acid biosynthesis. Overall, our results provide novel insights into the function of Elovl8a and Elovl8b, representing additional fatty acid elongases not previously described in chordates.elovl8b - / - ) zebrafish using CRISPR/Cas9 technology. Fatty acid composition in vivo and zebrafish liver cell experiments suggest that the substrate preference of Elovl8 overlapped with other existing Elovl enzymes. Zebrafish Elovl8a could elongate the polyunsaturated fatty acids (PUFAs) C18:2n-6 and C18:3n-3 to C20:2n-6 and C20:3n-3, respectively. Along with PUFA, zebrafish Elovl8b also showed the capacity to elongate C18:0 and C20:1. Gene expression quantification suggests that Elovl8a and Elovl8b may play a potentially important role in fatty acid biosynthesis. Overall, our results provide novel insights into the function of Elovl8a and Elovl8b, representing additional fatty acid elongases not previously described in chordates.

Background: Paeonia ostii seeds were identified as novel sources of edible plant oil with a high proportion of α-linolenic acid, a type of n-3 fatty acid with many health benefits. Due to the unreliability of seed oil content and quality, it is necessary to discover the mechanism underlying lipid biosynthesis in Paeonia ostii seeds., Objectives: This study aimed to identify the key genes involved in lipid biosynthesis in Paeonia ostii seeds by analyzing the relationship among the seed characteristics and the expression patterns of lipid genes in Paeonia ostii during seed development., Methods: Preliminary research on Paeonia ostii seed development was carried out from 10 days after pollination until maturity, focusing on phenology, oil content and lipid profiles. In addition, we investigated the spatiotemporal expression of 36 lipid biosynthetic genes in Paeonia ostii by using quantitative real-time PCR., Results: The results suggested that the development of Paeonia ostii seeds from pollination to maturity could be divided into three periods. The 36 lipid genes showed various spatiotemporal expression patterns and five gene groups with distinct temporal patterns during seed development were identified by clustering analysis of expression data. Furthermore, the relationships between gene expression and lipid/fatty acid accumulation and some candidate key lipid genes were discussed., Conclusions: This study provided the global patterns of fatty acid and lipid biosynthesis-related gene expression, which are critical to understanding the molecular basis of lipid biosynthesis and identifying the lipid accumulation rate-limiting genes during seed development., (© 2021. The Genetics Society of Korea.)

Objective: Mitochondrial aconitase (ACO2) is an essential enzyme that bridges the TCA cycle and lipid metabolism. However, its role in cancer development remains to be elucidated. The metabolic subtype of colorectal cancer (CRC) was recently established. We investigated ACO2's potential role in CRC progression through mediating metabolic alterations., Methods: We compared the mRNA and protein expression of ACO2 between paired CRC and non-tumor tissues from 353 patients. Correlations between ACO2 levels and clinicopathological features were examined. CRC cell lines with knockdown or overexpression of ACO2 were analyzed for cell proliferation and tumor growth. Metabolomics and stable isotope tracing analyses were used to study the metabolic alterations induced by loss of ACO2., Results: ACO2 decreased in >50% of CRC samples compared with matched non-tumor tissues. Decreased ACO2 levels correlated with advanced disease stage (P < 0.001) and shorter patient survival (P < 0.001). Knockdown of ACO2 in CRC cells promoted cell proliferation and tumor formation, while ectopic expression of ACO2 restrained tumor growth. Specifically, blockade of ACO2 caused a reduction in TCA cycle intermediates and suppression of mitochondrial oxidative phosphorylation, resulting in an increase in glycolysis and elevated citrate flux for fatty acid and lipid synthesis. Increased citrate flux induced upregulation of stearoyl-CoA desaturase (SCD1), which enhanced lipid desaturation in ACO2-deficent cells to favor colorectal cancer growth. Pharmacological inhibition of SCD selectively reduced tumor formation of CRC with ACO2 deficiency., Conclusions: Our study demonstrated that the rewiring metabolic pathway maintains CRC survival during compromised TCA cycles and characterized the therapeutic vulnerability of lipid desaturation in a meaningful subset of CRC with mitochondrial dysfunction., Competing Interests: CONFLICT OF INTEREST The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 The Authors. Published by Elsevier GmbH.. All rights reserved.)

Non-alcoholic fatty liver disease (NAFLD) is a chronic metabolic liver disease associated with obesity and insulin resistance. Activation of the purinergic receptor P2Y2R has been reported to promote adipogenesis, inflammation and dyslipidemia in adipose tissues in obese mice. However, the role of P2Y2R and its mechanisms in NAFLD remain unknown. We hypothesized that P2Y2R deficiency may play a protective role in NAFLD by modulating lipid metabolism in the liver. In this study, we fed wild type and P2Y2R knockout mice with a high-fat diet (HFD) for 12 weeks and analyzed metabolic phenotypes. First, P2Y2R deficiency effectively improved insulin resistance with a reduction in body weight and plasma insulin. Second, P2Y2R deficiency attenuated hepatic lipid accumulation and injury with reduced alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels. Third, P2Y2R deficiency decreased the expression of fatty acid synthesis mediators (cluster of differentiation (CD36), fatty acid synthase (FAS), and stearoyl-CoA desaturase 1 (SCD1)); and increased the expression of adipose triglyceride lipase (ATGL), a lipolytic enzyme. Mechanistically, P2Y2R deficiency increased the AMP-activated protein kinase (AMPK) activity to improve mitochondrial fatty acid β-oxidation (FAO) by regulating acetyl-CoA carboxylase (ACC) and carnitine palmitoyltransferase 1A (CPT1A)-mediated FAO pathway. In addition, P2Y2R deficiency increased peroxisome proliferator-activated gamma co-activator-1α (PGC-1α)-mediated mitochondrial biogenesis. Conclusively, P2Y2R deficiency ameliorated HFD-induced hepatic steatosis by enhancing FAO through AMPK signaling and PGC-1α pathway, suggesting P2Y2R as a promising therapeutic target for NAFLD.

Fatty acid metabolism is essential for the biogenesis of cellular components and ATP production to sustain proliferation of cancer cells. Long-chain fatty acyl-CoA synthetases (ACSLs), a group of rate-limiting enzymes in fatty acid metabolism, catalyze the bioconversion of exogenous or de novo synthesized fatty acids to their corresponding fatty acyl-CoAs. In this study, systematical analysis of ACSLs levels and the amount of fatty acyl-CoAs illustrated that ACSL1 were significantly associated with the levels of a broad spectrum of fatty acyl-CoAs, and were elevated in human prostate tumors. ACSL1 increased the biosynthesis of fatty acyl-CoAs including C16:0-, C18:0-, C18:1-, and C18:2-CoA, triglycerides and lipid accumulation in cancer cells. Mechanistically, ACSL1 modulated mitochondrial respiration, β-oxidation, and ATP production through regulation of CPT1 activity. Knockdown of ACSL1 inhibited the cell cycle, and suppressed the proliferation and migration of prostate cancer cells in vitro, and growth of prostate xenograft tumors in vivo. Our study implicates ACSL1 as playing an important role in prostate tumor progression, and provides a therapeutic strategy of targeting fatty acid metabolism for the treatment of prostate cancer.

The black bean is a legume widely consumed in Latin America, however its consumption has decreased significantly in recent decades. There is evidence that its consumption generates beneficial health effects due in part to the type of protein, resistant starches and polyphenols. Thus, their use in food formulation could impact health status. Therefore, the purpose of the present work was to evaluate the effects of the consumption of a bean protein concentrate (BPC) and a whole cooked bean flour (WCB) on body composition, glucose metabolism and energy expenditure in Wistar rats fed a control diet or high-fat diets with 5% sucrose in the drinking water. With this aim, rats were fed the experimental diets for 10 weeks. The results showed that consumption of either BPC or WCB reduced weight gain and body fat despite the consumption of a high-fat diet. This change was associated with a significant increase in energy expenditure and the capacity to adapt fuel oxidation to fuel availability. As a result, rats fed a bean-based diet had lower circulating glucose and insulin concentrations and normal glucose tolerance, which was associated with decreased expression of lipogenic genes in the liver. These results suggest that the type of protein and bioactive compounds particularly phenolic and flavonoid compounds present in BPC are suitable to improve the formulations used in dietary strategies for subjects with obesity or type 2 diabetes. The addition of legumes to the diet of subjects with insulin resistance, including black beans, could improve their metabolic status.

To evaluate the effects of fatty acids on endoplasmic reticulum (ER) stress, oxidative stress, and lipid damage. We treated BRL3A rat liver cells with, linoleic (LA), linolenic, oleic (OA), palmitic (PA), palmitoleic (POA), or stearic (SA) acid for 12 hr. The characteristics of cell lipid deposition, oxidative stress indexes, ER stress markers, nuclear factor κB p65 (NF-κB p65), lipid synthesis and transport regulators, and cholesterol metabolism regulators were analyzed. Endoplasmic chaperones like glucose-regulated protein 78, CCAAT-enhancer-binding protein, NF-κB p65, hydrogen peroxide, and malonaldehyde in PA- and SA-treated cells were significantly higher than in other treated cells. Deposition of fatty acids especially LA and POA were significantly increased than in other treated cells. De novo lipogenesis regulators sterol regulatory element-binding protein 1c, fatty acid synthase, and acetyl-coenzyme A carboxylase 1 (ACC1) expression were significantly increased in all fatty acid stimulation groups, and PA- and SA-treated cells showed lower p-ACC1 expression and higher scd1 expression than other fatty acid groups. Very low-density lipoprotein synthesis and apolipoprotein B100 expression in free fatty acids treated cells were significantly lower than control. PA, SA, OA, and POA had shown significantly increased cholesterol synthesis than other treated cells. PA and SA showed the lower synthesis of cytochrome P7A1 and total bile acids than other fatty acids treated cells. Excess of saturated fatty acids led to severe ER and oxidative stress. Excess unsaturated fatty acids led to increased lipid deposition in cultured hepatocytes. A balanced fatty acid intake is needed to maintain lipid homeostasis., (© 2020 Wiley Periodicals, Inc.)

The de novo synthesis of fatty acids has emerged as a therapeutic target for various diseases, including cancer. Because cancer cells are intrinsically buffered to combat metabolic stress, it is important to understand how cells may adapt to the loss of de novo fatty acid biosynthesis. Here, we use pooled genome-wide CRISPR screens to systematically map genetic interactions (GIs) in human HAP1 cells carrying a loss-of-function mutation in fatty acid synthase (FASN), whose product catalyses the formation of long-chain fatty acids. FASN-mutant cells show a strong dependence on lipid uptake that is reflected in negative GIs with genes involved in the LDL receptor pathway, vesicle trafficking and protein glycosylation. Further support for these functional relationships is derived from additional GI screens in query cell lines deficient in other genes involved in lipid metabolism, including LDLR, SREBF1, SREBF2 and ACACA. Our GI profiles also identify a potential role for the previously uncharacterized gene C12orf49 (which we call LUR1) in regulation of exogenous lipid uptake through modulation of SREBF2 signalling in response to lipid starvation. Overall, our data highlight the genetic determinants underlying the cellular adaptation associated with loss of de novo fatty acid synthesis and demonstrate the power of systematic GI mapping for uncovering metabolic buffering mechanisms in human cells.

Gut-derived satiety hormones provide negative feedback to suppress food intake and maintain metabolic function in peripheral tissues. Despite the wealth of knowledge of the systemic effects of these hormones, very little is known concerning the mechanisms by which nutrients, such as dietary fats, can promote the expression of genes involved in L-cell hormone production. We have tested the role of various dietary fats and found that after hydrolysis into free fatty acids (FFA's), there is a differential response in the extent to which they induce PYY gene and protein production. The effect of FFA's also seems to relate to triglyceride (TG) re-esterification rate, with MUFA re-esterifying faster with lower PYY production. We have also found that there are differences in potency of FFA's based on their desaturation patterns in vitro. The potency effect of FFA's is influenced by the rate of TG re-esterification, such that the longer FFA's are in contact with L-cells, the more PYY they produce. We found that chronic consumption of high-fat diets enables the small intestine to re-esterify FFA's into TG faster and earlier which resulted in a blunted postprandial PYY response. Lastly, we found that FFA's induce X-box-binding protein-1 activation (Xbp1s) in L-cells and that adenoviral delivery of Xbp1s was sufficient to induce PYY gene expression. Taken together, the present work indicates that dietary fat can induce satiety, in part, prior to re-esterification. Chronic high-fat diet consumption increases the rate of re-esterification which diminishes satiety and may lead to increased food intake. Targeting intestinal TG synthesis may prove beneficial in restoring obesity-associated reductions in postprandial satiety., Competing Interests: The authors declare no conflict of interest.

Salt-inducible kinase 2 (SIK2) has been established as a regulator of diverse biological processes including cell metabolism. A recent study has reported that SIK2 is required for adipocyte-induced ovarian cancer (OC) survival through facilitating fatty acid oxidation. However, whether SIK2 also plays a role in the lipid synthesis in OC cells remains elusive. Here, we showed that SIK2 significantly promoted the lipid synthesis in OC cells. On the one hand, SIK2 enhanced fatty acid synthesis through upregulating the expression of sterol regulatory element binding protein 1c (SREBP1c) and thus the transcription of major lipogenic enzyme FASN. On the other hand, SIK2 promoted cholesterol synthesis through upregulating the expression of sterol regulatory element binding protein 2 (SREBP2) and thus the transcription of major cholesterol synthesis enzymes HMGCR. Moreover, PI3K/Akt signaling pathway was found to be involved in the upregulation of SREBP1c and SREBP2 in OC cells. Moreover, in vitro and in vivo assays indicated that the SIK2-regulated fatty acid and cholesterol synthesis played a critical role in the growth of OC cells. Our findings demonstrate that SIK2 is a critical regulator of lipid synthesis in OC cells and thus promotes OC growth, which provides a strong line of evidence for this molecule to be used as a therapeutic target in the treatment of this malignancy.

Objectives: The objective of this work was to determine the specific mechanisms by which resveratrol inhibits lipogenesis and stimulates lipolysis., Methods: Twelve male mice were individually introduced into a metabolic cage for 24 h to measure basal metabolic rate, prior to intervention. They were randomly divided into two groups, resveratrol (RSV) and control (C), and administered resveratrol intraperitoneally or vehicle, respectively, for two consecutive days. After 24 h, the metabolic energy expenditure was again determined for 24 h, before mice were sacrificed. Protein and gene expression of different enzymes related to metabolism in the hepatic tissue, adipose tissue and gastrocnemius of mice were analyzed by RT-PCR, western blot or ELISA., Results: We report that resveratrol lowers the respiratory quotient in old mice and that this may be due to the activation of fatty acid mobilization from white adipose tissue (because hormone-activated lipase expression is increased) and fatty acid transport into mitochondria and eventual oxidation in muscle and liver (because transport enzymes and beta oxidation enzymes are also increased). Indeed, we have observed that resveratrol in vivo causes an increase in the expression and phosphorylation of AMPKα in liver, muscle and adipose tissue and an increase in the expression of acyl-CoA synthetase, of carnitine palmitoyl transferase 1 and of carnitine acylcarnitine translocase, all enzymes involved in lipid catabolism. On the other hand, the levels of acetyl-CoA carboxylase as well as those its product, i.e. malonyl CoA, are decreased., Conclusions: We conclude that a controlled dose of resveratrol activates fatty acid mobilization and degradation and inhibits fatty acid synthesis in old mice. This is the first time that these effects of resveratrol in lipid metabolism in healthy old (non-obese) animals are reported., (Copyright © 2019 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Prunus persica (L.) Batsch is a deciduous fruit tree cultivated worldwide. The flower of P. persica (PPF), commonly called the peach blossom, is currently consumed as a tea for weight loss in East Asia; however, its anti-obesity effects have yet to be demonstrated in vitro or in vivo. Since PPF is rich in phytochemicals with anti-obesity properties, we aimed to investigate the effects of PPF on obesity and its underlying mechanism using a diet-induced obesity model. Male C57BL/6 mice were fed either normal diet, high-fat diet (HFD), or HFD containing 0.2% or 0.6% PPF water extract for 8 weeks. PPF significantly reduced body weight, abdominal fat mass, serum glucose, alanine transaminase and aspartate aminotransferase levels, and liver and spleen weights compared to the HFD control group. Real-time quantitative polymerase chain reaction analysis revealed that PPF suppressed lipogenic gene expression, including stearoyl-CoA desaturase-1 and -2 and fatty acid synthase, and up-regulated the fatty acid β-oxidation gene, carnitine palmitoyltransferase-1, in the liver. Our results suggest that PPF exerts anti-obesity effects in obese mice and these beneficial effects might be mediated through improved hepatic lipid metabolism by reducing lipogenesis and increasing fatty acid oxidation.

Hepatic trefoil factor 3 (Tff3) was identified as a potential protein for the treatment of diabetes, yet the effect of Tff3 on nonalcoholic fatty liver disease (NAFLD) has never been explored. Here, we found that the expression of hepatic Tff3 was significantly decreased in NAFLD mice models, suggesting that Tff3 was a potential marker gene for NAFLD. Restoring the expression of Tff3 in the liver of NAFLD mice, including diabetic (db), obese (ob/ob), and diet-induced obese mice, with adenovirus-mediated Tff3 ( Ad-Tff3 ) apparently attenuates the fatty liver phenotype. In contrast, adenovirus-mediated knockdown of Tff3 ( Ad-shTff3 ) in C57BL/6J mice results in an obvious fatty liver phenotype. Furthermore, our molecular experiments indicated that hepatic Tff3 could alleviate hepatic steatosis via upregulating the expression of peroxisome proliferator-activated receptor-α ( PPARα ) directly, thereby enhancing the fatty acid oxidation process in the liver. Notably, we found that Tff3 attenuates the fatty liver phenotype independent of modulation of lipogenesis and improves the capacity of anti-inflammation. Overall, our results suggested that hepatic Tff3 could be effectively used as a potential therapy target for the treatment of NAFLD.

Disruption of endoplasmic reticulum (ER) homeostasis, often termed ER stress, is intrinsically linked with perturbation of lipid metabolism in humans and mice. Whether ER homeostasis is affected in cows experiencing fatty liver is unknown. The aim of this study was to investigate the potential role of ER stress in hepatic lipid accumulation in calf hepatocytes and ER stress status in dairy cows with severe fatty liver. In vitro experiments were conducted in which hepatocytes were isolated from calves and treated with different concentrations of fatty acids, tauroursodeoxycholic acid (TUDCA; a canonical inhibitor of ER stress), or both. The increase in phosphorylation level of protein kinase RNA-like ER kinase (PERK) and inositol requiring protein-1α (IRE1α) proteins, and the cleavage of activating transcription factor-6 (ATF6) protein in response to increasing doses of fatty acids (which were reversed by TUDCA treatment) in primary hepatocytes underscored a mechanistic link between fatty acids and ER stress. In addition, fatty acid treatment increased the abundance of sterol regulatory element-binding protein 1c, acetyl-CoA carboxylase-α, fatty acid synthase, and diacylglycerol acyltransferase 1, and lipid accumulation in calf primary hepatocytes, whereas inhibition of ER stress by incubating with TUDCA significantly weakened these effects. Overall, results in vitro indicate that inhibition of ER stress in calf hepatocytes alleviates fatty acid-induced lipid accumulation by downregulating the expression of lipogenic genes. In vivo experiments, liver and blood samples were collected from cows diagnosed as healthy (n = 15) or with severe fatty liver (n = 15). The phosphorylation level of PERK and IRE1α, the cleavage of ATF6 protein, and the abundance of several unfolded protein response genes (78 kDa glucose-regulated protein, AMP-dependent transcription factor 4, and spliced X-box binding protein 1) were greater in liver of cows with severe fatty liver. The present in vivo study confirms the occurrence of ER stress in dairy cows with severe fatty liver. Considering the causative role of fatty acid-induced ER stress in hepatic lipid accumulation in calf hepatocytes, the existence of ER stress in the liver of severe fatty liver cows may presage its participation in fatty liver progression in dairy cows. However, the mechanistic relationship between ER stress and fatty liver in dairy cows remain to be determined., (Copyright © 2019 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Fatty acid synthesis is regulated by transcription factors SREBPs and their escort protein SCAP. Malignant cells become dependent on de novo lipogenesis, which sustains rapid proliferation and resistance to cellular stress. Increasing evidence showed SCAP participated in various disease processes including malignant tumors, which regulate transcription factors SREBPs Tumorigenesis is associated with incur glucose consumption and lipogenesis. In our study, we discovered that SCAP was upregulated in BC tissues. SCAP knockdown by CRISPR-Cas9 inhibit the cell proliferation, invasion and migration. Additionally, the cell apoptosis was facilitated. What's more, downregulation of SCAP could weaken the cancer-promoting effects of estrogen on BC. Our study revealed that SCAP played a carcinogenic role in BC and lipogenesis might promote the initiation of BC by inducing SCAP. Thus, Targeting SCAP may provide a promising means of treating BC and a new perspective for the tumorigenesis of bladder cancer., Competing Interests: Competing Interests: The authors have declared that no competing interest exists.

Castration is an important means of improving the beef quality via increasing fat deposition. However, little is known about the molecular mechanism underlying the fat deposition after castration. Here, the intramuscular fat (IMF) content of the steer group was shown to be much higher than the bull group. To understand transcriptional changes in the genes involved in fat deposition following castration, differential expression patterns of mRNAs in liver tissue were investigated in steers and bulls using RNA sequencing. In total, we obtained 58,282,367-54,918,002 uniquely mapped reads, which covered 90.13% of the currently annotated transcripts; 5,864 novel transcripts and optimized 9,088 known genes were determined. These results indicated that castration could change the expression patterns of mRNAs in liver tissue, and 282 differentially expressed genes (DEGs) were detected between steers and bulls. KEGG pathway analysis showed that the DEGs were mostly enriched in PPAR signaling pathway, steroid biosynthesis, steroid hormone biosynthesis, and biosynthesis of fatty acids. Furthermore, eight DEGs were corroborated via quantitative real-time PCR and we found that FABP1 gene knockdown in bovine hepatocytes prominently reduced intracellular triacylglycerol (TAG) synthesis and very low density lipoprotein (VLDL) secretion in culture medium. In summary, these results indicate that FABP1 may promote fat deposition by promoting the production and secretion of TAG and VLDL in steer liver., Competing Interests: The authors have declared that no competing interests exist.

The aim of this study was to determine the effects of isonitrogenous and isocaloric diets containing different qualities of forages and concentrate content on milk fat composition and genes that encode mammary lipogenic enzymes in dairy cows. A total of 20 Holstein cows were assigned to 1 of 2 treatment diets composed of either mixed forages (MF, starch : 21.50%) or corn stover forage (CS, starch : 25.39%). Mammary tissue biopsies were performed to analyze the mRNA expression of lipogenic enzymes. Dry matter intake, body weight, milk protein, and lactose were not affected by treatments. The milk yield, fat content and saturated fatty acid (SFA) and short- and medium-chain fatty acid (SMFA) contents in milk were lower in the CS diet than in the MF diet, but the unsaturated FA and long-chain FA contents were higher. Genes involved in de novo FA synthesis, FA uptake and transport, and Δ9-desaturation were lower in the CS treatment than in the MF treatment. No effects on the nuclear transcription factors were observed between the two treatments. The data indicated that corn stover diet reduced the milk yield, fat content, SMFA, and SFA contents in milk, as well as the gene expression of mammary lipogenic enzymes in dairy cows., (© 2018 Japanese Society of Animal Science.)

Commercialization of algal lipids and biofuels is still impractical owing to the unavailability of lipogenic strains and lack of economically viable oil extraction strategies. Because lipogenesis is governed by multiple factors, success in generating industrial-suitable algal strains using conventional strategies has been limited. We report the discovery of a novel bZIP1 transcription factor, NobZIP1, whose overexpression results in a remarkable elevation of lipid accumulation and lipid secretion in a model microalga Nannochloropsis oceanica , without impairing other physiological properties. Chromatin immunoprecipitation-quantitative PCR analysis revealed that the key genes up- and down-regulated by NobZIP1 are involved in lipogenesis and cell wall polymer synthesis, respectively, which, in turn, induce lipid overproduction and secretion. Among these regulated genes, UDP-glucose dehydrogenase was shown to alter cell wall composition, thus also boosting lipid secretion. In summary, these results offer a comprehensive strategy for concurrent lipid overproduction and secretion, strongly increasing the commercial potential of microalgae.

Oxyresveratrol (OXY) is a naturally occurring polyhydroxylated stilbene that is abundant in mulberry wood (Morus alba L.), which has frequently been supplied as a herbal medicine. It has been shown that OXY has regulatory effects on inflammation and oxidative stress, and may have potential in preventing or curing nonalcoholic fatty liver disease (NAFLD). This study examined the effects of OXY on in vitro model of NAFLD in hepatocyte by the liver X receptor α (LXRα)-mediated induction of lipogenic genes and in vivo model in mice along with its molecular mechanism. OXY inhibited the LXRα agonists-mediated sterol regulatory element binding protein-1c (SREBP-1c) induction and expression of the lipogenic genes and upregulated the mRNA of fatty acid β-oxidation-related genes in hepatocytes, which is more potent than genistein and daidzein. OXY also induced AMP-activated protein kinase (AMPK) activation in a time-dependent manner. Moreover, AMPK activation by the OXY treatment helped inhibit SREBP-1c using compound C as an AMPK antagonist. Oral administration of OXY decreased the Oil Red O stained-positive areas significantly, indicating lipid droplets and hepatic steatosis regions, as well as the serum parameters, such as fasting glucose, total cholesterol, and low density lipoprotein-cholesterol in high fat diet fed-mice, as similar with orally treatment of atorvastatin. Overall, this result suggests that OXY has the potency to inhibit hepatic lipogenesis through the AMPK/SREBP-1c pathway and can be used in the development of pharmaceuticals to prevent a fatty liver., (Copyright © 2018. Published by Elsevier B.V.)

Myelination calls for a remarkable surge in cell metabolism to facilitate lipid and membrane production. Endogenous fatty acid (FA) synthesis represents a potentially critical process in myelinating glia. Using genetically modified mice, we show that Schwann cell (SC) intrinsic activity of the enzyme essential for de novo FA synthesis, fatty acid synthase (FASN), is crucial for precise lipid composition of peripheral nerves and fundamental for the correct onset of myelination and proper myelin growth. Upon FASN depletion in SCs, epineurial adipocytes undergo lipolysis, suggestive of a compensatory role. Mechanistically, we found that a lack of FASN in SCs leads to an impairment of the peroxisome proliferator-activated receptor (PPAR) γ-regulated transcriptional program. In agreement, defects in myelination of FASN-deficient SCs could be ameliorated by treatment with the PPARγ agonist rosiglitazone ex vivo and in vivo . Our results reveal that FASN-driven de novo FA synthesis in SCs is mandatory for myelination and identify lipogenic activation of the PPARγ transcriptional network as a putative downstream functional mediator., (© 2018 Montani et al.)

Akt serine/threonine kinase acts as a central mediator in the phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway, regulating a series of biological processes. In lipid metabolism, Akt activation regulates a series of gene expressions, including genes related to intracellular fatty acid synthesis. However, the regulatory mechanisms of Akt in dairy goat mammary lipid metabolism have not been elaborated. In this study, the coding sequences of goat Akt1 gene were cloned and analyzed. Gene expression of Akt1 in different lactation stages was also investigated. For in vitro studies, a eukaryotic expression vector of Akt1 was constructed and transfected to goat mammary epithelial cells (GMECs), and specific inhibitors of Akt/mammalian target of rapamycin (mTOR) signaling were applied to GMECs. Results showed that Akt1 protein was highly conserved, and its mRNA was highly expressed in midlactation. In vitro studies indicated that Akt1 phosphorylation activated mTOR and subsequently enhanced sterol regulatory element binding protein 1 (SREBP1), thus increasing intracellular triacylglycerol content. Inhibition of Akt/mTOR signaling down-regulated the gene expression of lipogenic genes. Overall, Akt1 plays an important role in regulating de novo fatty acid synthesis in goat mammary epithelial cells, and this process probably is through the mTOR/SREBP1 axis.

Sterol regulatory element binding protein 1 (SREBP-1) is well-known as the master regulator of lipogenesis in rodents. Acyl-CoA synthetase short-chain family member 2 (ACSS2) plays a key role in lipogenesis by synthesizing acetyl-CoA from acetate for lipogenesis. ATP citrate lyase (ACLY) catalyzes the conversion of citrate and coenzyme A to acetyl-CoA, hence, it is also important for lipogenesis. Although ACSS2 function in cancer cells has been elucidated, its essentiality in ruminant mammary lipogenesis is unknown. Furthermore, ACSS2 gene promoter and its regulatory mechanisms have not known. Expression of ACSS2 was high in lipid synthesizing tissues, and its expression increased during lactation compared with non-lactating period. Simultaneous knockdown of both ACSS2 and ACLY by siRNA in primary goat mammary epithelial cells decreased (p < 0.05) the mRNA abundance of genes associated with de novo fatty acid synthesis (FASN, ACACA, SCD1) and triacylglycerol (TAG) synthesis (DGAT1, DGAT2, GPAM, and AGPAT6). Genes responsible for lipid droplet formation and secretion (PLIN2 and PLIN3) and fatty acid oxidation (ATGL, HSL, ACOX, and CPT1A) all decreased (p < 0.05) after ACSS2 and ACLY knockdown. Total cellular TAG content and lipid droplet formation also decreased. Use of a luciferase reporter assay revealed a direct regulation of ACSS2 by SREBP-1. Furthermore, SREBP-1 interacted with an SRE (SREBP response element) spanning at -475 to -483 bp on the ACSS2 promoter. Taken together, our results revealed a novel pathway that SREBP-1 may regulate fatty acid and TAG synthesis by regulating the expression of ACSS2., (© 2017 Wiley Periodicals, Inc.)

Adipose-derived mesenchymal stem cells (ADSCs) are useful cell model to study adipogenesis and energy metabolism. However, the biological characteristics of bovine ADSCs (bADSCs) remain unclear. This study aimed to isolate and identify bADSCs and further investigate fatty acid (FA)-related gene expression and composition of FAs during adipogenesis. The growth curve showed the bADSCs of P5 cells had rapid proliferation superior to P10-P50. The colony formation assay showed colony number of P5 cells was higher than that of P50 cells (51.67 ± 3.06 vs 35.67 ± 6.43, P < 0.05). The immunofluorescence showed that bADSCs were positive for CD13, CD44, CD49d, CD90, CD105, and Vimentin while negative for CD34. The multipotential towards adipocyte, osteocyte, and chondrocyte was confirmed by specific histological staining and lineage gene expression. During adipogenic induction, the genes related to lipogenesis and lipolysis were assessed by real-time PCR and the FA composition was detected by GC-MS. Expression of lipogenesis-related genes showed coordinated regulation as peaking on day 7 and declining until induction ended, including PPARγ, SREBP1, ACC1, FAS, ELOVL6, SCD1, and FABP4. FA deposition-related genes (DGAT1 and ACAT1) increased until day 14. Lipolysis genes (CPT-1A, VLCAD, and ACO) showed a variant expression pattern. The profile of FAs showed that proportion of the FAs (C4-C15, ≥ C22) increased, but proportion of long-chain fatty acids (C16-C20) reduced after induction. And saturated FAs (SFA) decreased while monounsaturated FAs (MUFA) and polyunsaturated FAs (PUFA) increased during adipogenesis. These data suggest that bADSCs possess the characteristics of mesenchymal stem cells and have active de novo lipogenesis (DNL) and desaturation of FAs during adipogenesis.

Nonalcoholic fatty liver disease (NAFLD) is frequently observed in obese and aged individuals. Peroxisome proliferator-activated receptors (PPARs) play a role in regulating hepatic lipid accumulation, a hallmark of NAFLD development. A PPAR pan agonist, 2-(4-(5,6-methylenedioxybenzo[d]thiazol-2-yl)-2-methylphenoxy)-2-methylpropanoic acid (MHY2013) has been shown to prevent fatty liver formation and insulin resistance in obese mice (db/db) model. However, the beneficial effects of MHY2013 in aged model remain unknown. In this study, we investigated whether MHY2013 alleviates hepatic lipid accumulation in aged Sprague-Dawley (SD) rats. We confirmed that MHY2013 increased the activities of three PPAR subtypes in HepG2 cells using luciferase assay. When administered orally in aged SD rats, MHY2013 markedly decreased the hepatic triglyceride levels without changes in body weight. Regarding underlying mechanisms, MHY2013 increased the mRNA levels of lipid oxidation-related genes, including carnitine palmitoyltransferase 1 (CPT1) and peroxisomal acyl-CoA oxidase 1 (ACOX1), without apparent change in the mRNA expression of lipogenesis-related genes. Furthermore, MHY2013 significantly increased systemic fibroblast growth factor 21 (FGF21) and adiponectin levels and suppressed inflammatory mRNA expression in the liver. In conclusion, MHY2013 alleviated age-related hepatic lipid accumulation, in part by upregulating β-oxidation signaling and suppressing inflammation in the liver. Therefore, MHY2013 is a potential pharmaceutical agent for treating age-related hepatic lipid accumulation.

The present study assessed the effect of feeding palm oil (PO), sunflower oil (SO) and their combination on performance, fat deposition, fatty acid composition and lipogenic gene expression of broilers reared for 42 days. A total of 144 1-day-old broilers (Cobb500) were randomly allotted into four treatment diets with each having six replicates of six chicks in each replicate following a completely randomized design. Live weight gain and feed efficiency was significantly (P < 0.05) higher in birds fed with a combination of oil sources compared to controls. Birds fed with the combination of oil and SO alone had higher carcass yield and lower abdominal fat. Higher (P < 0.05) concentrations of unsaturated fatty acids (UFA) and lower concentrations of palmitic acid and saturated fatty acid (SFA) was found in birds fed SO alone and combinations of SO and PO. Furthermore, the outcomes showed that birds fed diet supplemented with SO and the combination of SO and PO down-regulated gene expression of key hepatic lipogenic enzymes of fatty acids synthase (FAS), acetyl-CoA carboxylase (ACC) and stearoyl-CoA desaturase (SCD). These findings suggest that the diet containing the combination of 2% PO and 4% SO may reduce hepatic lipogenesis, as well as lower abdominal fat content of broilers., (© 2017 Japanese Society of Animal Science.)

Hormone-sensitive lipase (HSL) is an intracellular neutral lipase capable of hydrolysing a variety of esters and is considered to be a candidate gene affecting fat deposition traits. Gene expression profiles of HSL were analysed in various adipose tissues of cattle, and the effect of HSL on lipid metabolism genes was analysed by a PCR array. Novel polymorphisms were identified within the HSL regulatory domain by sequencing, and the relationship between HSL variants and fat deposition traits was analysed. HSL mRNA was highly expressed in the subcutaneous and visceral fat of cattle. CPT1B/CPT1C and other lipocatabolic genes were upregulated, and lipogenesis-related genes (FASN, LPL and ACOT12) were downregulated by HSL overexpression in BFFs. Five novel variants in the HSL functional domain were significantly associated with fat deposition traits, including FCR, LBT, MFW and fatty acid composition. HSL plays a pivotal role in the regulation of lipolysis and fatty acid biosynthesis in beef cattle., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Cardiometabolic diseases are primarily linked to enlarged visceral adipose tissue (VAT). However, some data suggest heterogeneity within the subcutaneous adipose tissue (SAT) depot with potential metabolic differences between the superficial SAT (sSAT) and deep SAT (dSAT) compartments. We aimed to investigate the heterogeneity of these three depots with regard to fatty acid (FA) composition and gene expression. Adipose tissue biopsies were collected from 75 obese women undergoing laparoscopic gastric bypass surgery. FA composition and gene expression were determined with gas chromatography and quantitative real-time-PCR, respectively. Stearoyl CoA desaturase-1 (SCD-1) activity was estimated by product-to-precursor FA ratios. All polyunsaturated FAs (PUFA) with 20 carbons were consistently lower in VAT than either SAT depots, whereas essential PUFA (linoleic acid, 18:2n-6 and α-linolenic acid, 18:3n-3) were similar between all three depots. Lauric and palmitic acid were higher and lower in VAT, respectively. The SCD-1 product palmitoleic acid as well as estimated SCD-1 activity was higher in VAT than SAT. Overall, there was a distinct association pattern between lipid metabolizing genes and individual FAs in VAT. In conclusion, SAT and VAT are two distinct depots with regard to FA composition and expression of key lipogenic genes. However, the small differences between sSAT and dSAT suggest that FA metabolism of SAT is rather homogenous.

White adipose tissue (WAT) plays a central role in whole-body energy homeostasis through storage and release of fatty acids. A deeper understanding of the complex and highly integrated pathways regulating WAT fatty acid metabolism, and how they are altered with obesity, is necessary for diagnostic and therapeutic innovations in nutritional disorders. In this multi-omics study, we investigated the influence of obesity on fatty acid metabolism in human subcutaneous adipose tissue (SAT) using an approach that integrated transcriptomic, peptidomic, and fatty acid analyses. Notably, all analyses were conducted in the same adipose tissue sample from each participant, thus minimizing the chance of spurious results. In a sample of SAT from the periumbilical abdominal region of obese (n = 11, mean body mass index [BMI] = 35.0 ± 1.2 kg/m 2 ) and lean subjects (n = 9, mean BMI = 22.1 ± 0.5 kg/m 2 ), we found that obese SAT tended to have higher relative amounts of specific monounsaturated fatty acids and n-6 polyunsaturated fatty acids, and lower amounts of saturated fatty acids (p < 0.05). These changes were associated with differential regulation of lipogenic and lipolytic pathways in obese SAT. Fatty acid analysis showed changes in estimated fatty acid desaturase and elongase activities between lean and obese SAT (p < 0.05). Biomarkers of lipogenesis (e.g., fatty acid synthase protein) were differentially regulated between lean and obese SAT. These changes were noted in conjunction with increases in extracellular matrix remodeling proteins. Transcriptomic data revealed that the key regulators of lipolysis were reduced in obese SAT. This integrative multi-omics analysis collectively shows that obese SAT has a distinct fatty acid signature compared to lean SAT and the pathways underlying fatty acid metabolism are broadly regulated at the level of gene expression and protein abundance.

Background: In the present study, the effect of arginine and leucine supplementation, and dietary protein level, were investigated in commercial crossbred pigs to clarify their individual or combined impact on plasma metabolites, hepatic fatty acid composition and mRNA levels of lipid sensitive factors. The experiment was conducted on fifty-four entire male pigs (Duroc × Pietrain × Large White × Landrace crossbred) from 59 to 92 kg of live weight. Each pig was randomly assigned to one of six experimental treatments (n = 9). The treatments followed a 2 × 3 factorial arrangement, providing two levels of arginine supplementation (0 vs. 1%) and three levels of basal diet (normal protein diet, NPD; reduced protein diet, RPD; reduced protein diet with 2% of leucine, RPDL)., Results: Significant interactions between arginine supplementation and protein level were observed across plasma lipids. While dietary arginine increased total lipids, total cholesterol, HDL-cholesterol, LDL-cholesterol, VLDL-cholesterol and triacylglycerols in NPD, the inverse effect was observed in RPD. Overall, dietary treatments had a minor impact on hepatic fatty acid composition. RPD increased 18:1c9 fatty acid while the combination of leucine and RPD reduced 18:0 fatty acid. Arginine supplementation increased the gene expression of FABP1, which contributes for triacylglycerols synthesis without affecting hepatic fatty acids content. RPD, with or without leucine addition, upregulated the lipogenic gene CEBPA but downregulated the fat oxidation gene LPIN1., Conclusions: Arginine supplementation was responsible for a modulated effect on plasma lipids, which is dependent on dietary protein level. It consistently increased lipaemia in NPD, while reducing the correspondent metabolites in RPD. In contrast, arginine had no major impact, neither on hepatic fatty acids content nor on fatty acid composition. Likewise, leucine supplementation of RPD, regardless the presence of arginine, promoted no changes on total fatty acids in the liver. Ultimately, arginine, leucine and dietary protein reduction seem to be unrelated with fatty liver development.

Carbonic anhydrases are a family of enzymes that catalyze the reversible condensation of water and carbon dioxide to carbonic acid, which spontaneously dissociates to bicarbonate. Carbonic anhydrase III (Car3) is nutritionally regulated at both the mRNA and protein level. It is highly enriched in tissues that synthesize and/or store fat: liver, white adipose tissue, brown adipose tissue, and skeletal muscle. Previous characterization of Car3 knockout mice focused on mice fed standard diets, not high-fat diets that significantly alter the tissues that highly express Car3. We observed lower protein levels of Car3 in high-fat diet fed mice treated with niclosamide, a drug published to improve fatty liver symptoms in mice. However, it is unknown if Car3 is simply a biomarker reflecting lipid accumulation or whether it has a functional role in regulating lipid metabolism. We focused our in vitro studies toward metabolic pathways that require bicarbonate. To further determine the role of Car3 in metabolism, we measured de novo fatty acid synthesis with in vitro radiolabeled experiments and examined metabolic biomarkers in Car3 knockout and wild type mice fed high-fat diet. Specifically, we analyzed body weight, body composition, metabolic rate, insulin resistance, serum and tissue triglycerides. Our results indicate that Car3 is not required for de novo lipogenesis, and Car3 knockout mice fed high-fat diet do not have significant differences in responses to various diets to wild type mice.

Brown adipose tissue uptake of glucose and fatty acids is very high during nonshivering thermogenesis. Adrenergic stimulation markedly increases glucose uptake, de novo lipogenesis, and FA oxidation simultaneously. The mechanism that enables this concerted response has hitherto been unknown. Here, we find that in primary brown adipocytes and brown adipocyte-derived cell line (IMBAT-1), acute inhibition and longer-term knockdown of DGAT2 links the increased de novo synthesis of fatty acids from glucose to a pool of TAG that is simultaneously hydrolyzed, providing FA for mitochondrial oxidation. DGAT1 does not contribute to this pathway, but uses exogenous FA and glycerol to synthesize a functionally distinct pool of TAG to which DGAT2 also contributes. The DGAT2-dependent channelling of 14 C from glucose into TAG and CO 2 was reproduced in β3-agonist-stimulated primary brown adipocytes. Knockdown of DGAT2 in IMBAT-1 affected the mRNA levels of UCP1 and genes important in FA activation and esterification. Therefore, in β3-agonist activated brown adipocytes, DGAT2 specifically enables channelling of de novo synthesized FA into a rapidly mobilized pool of TAG, which is simultaneously hydrolyzed to provide substrates for mitochondrial fatty acid oxidation., (Copyright © 2017 by the American Society for Biochemistry and Molecular Biology, Inc.)

Tangshen formula (TSF), a well-prescribed traditional Chinese formula, has been used in the treatment of diabetic nephropathy. However, whether TSF ameliorates dyslipidemia and liver injury associated with diabetes remains unclear. In this study, we examined the effects of TSF on lipid profiles and hepatic steatosis in db/db mice. For this purpose, 8‑week-old db/db mice were treated with TSF or saline for 12 weeks via gavage and db/m mice were used as controls. Body weight and blood glucose levels were monitored weekly and bi-weekly, respectively. Blood samples were obtained for the analysis of lipids and enzymes related to hepatic function, and liver tissues were analyzed by histology, immunohistochemistry and molecular examination. The results revealed that TSF markedly reduced body weight, liver index [liver/body weight (LW/BW)] and improved lipid profiles, hepatic function and steatosis in db/db mice. TSF induced the phosphoralation of AMP-activated protein kinase and inhibited the activity of sterol regulatory element-binding protein 1 together with the inhibition of the expression of genes involved in de novo lipogenesis (DNL) and gluconeogenesis, such as fatty acid synthase (FAS), acetyl-CoA carboxylase (ACC), stearoyl CoA desaturase 1 (SCD1), glucose-6-phosphatase (G6pc) and phosphoenolpyruvate carboxykinase 1 (Pck1). Additionally, the silent mating type information regulation 2 homolog 1 (Sirt1)/peroxisome proliferator-activated receptor α (PPARα)/malonyl-CoA decarboxylase (MLYCD) cascade was potently activated by TSF in the liver and skeletal muscle of db/db mice, which led to enhanced fatty acid oxidation. These findings demonstrated that TSF attenuated hepatic fat accumulation and steatosis in db/db mice by inhibiting lipogenesis and augmenting fatty acid oxidation.

Listeria monocytogenes, the causative organism of the serious food-borne disease listeriosis, has a membrane abundant in branched-chain fatty acids (BCFAs). BCFAs are normally biosynthesized from branched-chain amino acids via the activity of branched chain α-keto acid dehydrogenase (Bkd), and disruption of this pathway results in reduced BCFA content in the membrane. Short branched-chain carboxylic acids (BCCAs) added as media supplements result in incorporation of BCFAs arising from the supplemented BCCAs in the membrane of L. monocytogenes bkd mutant MOR401. High concentrations of the supplements also effect similar changes in the membrane of the wild type organism with intact bkd. Such carboxylic acids clearly act as fatty acid precursors, and there must be an alternative pathway resulting in the formation of their CoA thioester derivatives. Candidates for this are the enzymes phosphotransbutyrylase (Ptb) and butyrate kinase (Buk), the products of the first two genes of the bkd operon. Ptb from L. monocytogenes exhibited broad substrate specificity, a strong preference for branched-chain substrates, a lack of activity with acetyl CoA and hexanoyl CoA, and strict chain length preference (C3-C5). Ptb catalysis involved ternary complex formation. Additionally, Ptb could utilize unnatural branched-chain substrates such as 2-ethylbutyryl CoA, albeit with lower efficiency, consistent with a potential involvement of this enzyme in the conversion of the carboxylic acid additives into CoA primers for BCFA biosynthesis., (Published by Elsevier B.V.)

Desi-type chickpeas, which have long been used as a natural treatment for diabetes, have been reported to lower visceral adiposity, dyslipidemia and insulin resistance induced by a chronic high-fat diet in rats. In this study, in order to examine the effects of chickpeas of this type in an in vitro system, we used the 3T3-L1 mouse cell line, a subclone of Swiss 3T3 cells, which can differentiate into cells with an adipocyte-like phenotype, and we used ethanol extracts of chickpeas (ECP) instead of chickpeas. Treatment of the 3T3-L1 cells with ECP led to a decrease in the lipid content in the cells. The desaturation index, defined as monounsaturated fatty acids (MUFAs)/saturated fatty acids (SFAs), was also decreased by ECP due to an increase in the cellular content of SFAs and a decrease in the content of MUFAs. The decrease in this index may reflect a decreased reaction from SFA to MUFA, which is essential for fat storage. To confirm this hypothesis, we conducted a western blot analysis, which revealed a reduction in the amount of stearoyl-CoA desaturase 1 (SCD1), a key enzyme catalyzing the reaction from SFA to MUFA. We observed simultaneous inactivations of enzymes participating in lipogenesis, i.e., liver kinase B1 (LKB1), acetyl-CoA carboxylase (ACC) and AMPK, by phosphorylation, which may lead to the suppression of reactions from acetyl-CoA to SFA via malonyl-CoA in lipogenesis. We also investigated whether lipolysis is affected by ECP. The amount of carnitine palmitoyltransferase 1 (CPT1), an enzyme important for the oxidation of fatty acids, was increased by ECP treatment. ECP also led to an increase in uncoupling protein 2 (UCP2), reported as a key protein for the oxidation of fatty acids. All of these results obtained regarding lipogenesis and fatty acid metabolism in our in vitro system are consistent with the results previously shown in rats. We also examined the effects on SCD1 and lipid contents of ethanol extracts of Kabuli-type chickpeas, which are used worldwide. The effects were similar, but of much lesser magnitude compared to those of ECP described above. Thus, Desi-type chickpeas may prove to be effective for the treatment of diabetes, as they can alter the lipid content, thus reducing fat storage.

This study examined the effect of linseed and algae on growth and carcass parameters, adipocyte cellularity, fatty acid profile and meat quality and gene expression in subcutaneous and intramuscular adipose tissues (AT) in lambs. After weaning, 33 lambs were fed three diets up to 26.7 ± 0.3 kg: Control diet (barley and soybean); L diet (barley, soybean and 10% linseed) and L-A diet (barley, soybean, 5% linseed and 3.89% algae). Lambs fed L-A diet showed lower average daily gain and greater slaughter age compared to Control and L (P < 0.001). Carcass traits were not affected by L and L-A diets, but a trend towards greater adipocyte diameter was observed in L and L-A in the subcutaneous AT (P = 0.057). Adding either linseed or linseed and algae increased α-linolenic acid and eicosapentaenoic acid contents in both AT (P < 0.001); however, docosahexaenoic acid was increased by L-A (P < 0.001). The n-6/n-3 ratio decreased in L and L-A (P < 0.001). Algae had adverse effects on meat quality, with greater lipid oxidation and reduced ratings for odor and flavor. The expression of lipogenic genes was downregulated in the subcutaneous AT (P < 0.05): acetyl-CoA carboxylase 1 (ACACA) in L and L-A and lipoprotein lipase (LPL) and stearoyl-CoA desaturase (SCD) in L-A. Fatty acid desaturase 1 (FADS1), fatty acid desaturase 2 (FADS2) and fatty acid elongase 5 (ELOVL5) were unaffected. In the subcutaneous AT, supplementing either L or L-A increased peroxisome proliferator-activated receptor gamma (PPARG) and CAAT-enhancer binding protein alpha (CEBPA) (P < 0.05), although it had no effect on sterol regulatory element-binding factor 1 (SREBF1). In the intramuscular AT, expression of ACACA, SCD, FADS1 and FADS2 decreased in L and L-A (P < 0.001) and LPL in L (P < 0.01), but PPARG, CEBPA and SREBF1 were unaffected.

Microalgae biosynthesize high amount of lipids and show high potential for renewable biodiesel production. However, the production cost of microalgae-derived biodiesel hampers large-scale biodiesel commercialization and new strategies for increasing lipid production efficiency from algae are urgently needed. Here we submitted the marine algae Phaeodactylum tricornutum to a 4-day dark stress, a condition increasing by 2.3-fold the total lipid cell quotas, and studied the cellular mechanisms leading to lipid accumulation using a combination of physiological, proteomic (iTRAQ) and genomic (qRT-PCR) approaches. Our results show that the expression of proteins in the biochemical pathways of glycolysis and the synthesis of fatty acids were induced in the dark, potentially using excess carbon and nitrogen produced from protein breakdown. Treatment of algae in the dark, which increased algal lipid cell quotas at low cost, combined with optimal growth treatment could help optimizing biodiesel production.

In nonruminants, thyroid hormone responsive (THRSP) is a crucial protein for cellular de novo lipogenesis. However, the role of THRSP in regulating the synthesis of milk fatty acid composition in goat mammary gland remains unknown. In the present study, we compared gene expression of THRSP among different goat tissues. Results revealed that THRSP had the highest expression in subcutaneous fat, and expression was higher during lactation compared with the dry period. Overexpression of THRSP upregulated the expression of fatty acid synthase (FASN), stearoyl-coenzyme A desaturase 1 (SCD1), diacylglycerol acyltransferase 2 (DGAT2), and glycerol-3-phosphate acyltransferase (GPAM) in goat mammary epithelial cells. In contrast, overexpression of THRSP led to downregulation of thrombospondin receptor (CD36) and had no effect on the expression of acetyl-coenzyme A carboxylase α (ACACA) and sterol regulatory element binding transcription factor1 (SREBF1). In addition, overexpressing THRSP in vitro resulted in a significant increase in triacylglycerol (TAG) concentration and the concentrations of C12:0 and C14:0. Taken together, these results highlight an important role of THRSP in regulating lipogenesis in goat mammary epithelial cells., (Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

The objective of this study was to demonstrate differences in aspects of adipose tissue cellularity, lipid metabolism, and fatty and cholesterol composition in Angus and Brahman crossbred cattle. We hypothesized that in vitro measures of lipogenesis would be greater in three-fourths Angus progeny than in three-fourths Brahman progeny, especially in intramuscular (i.m.) adipose tissue. Progeny ( = 227) were fed a standard, corn-based diet for approximately 150 d before slaughter. Breed was considered to be the effect of interest and was forced into the model. There were 9 breed groups including all 4 kinds of three-fourths Angus calves: Angus bulls Angus-sired F cows ( = 32), Angus bulls Brahman-sired F cows ( = 20), Brahman-sired F bulls Angus cows ( = 24), and Angus-sired F bulls Angus cows ( = 20). There were all 4 kinds of three-fourths Brahman calves: Brahman bulls Brahman-sired F cows ( = 21), Brahman bulls Angus-sired F cows ( = 43), Brahman-sired F bulls Brahman cows ( = 26), and Angus-sired F bulls Brahman cows ( = 13). Additionally, F calves (one-half Brahman and one-half Angus) were produced only from Brahman-sired F bulls Angus-sired F cows ( = 28). Contrasts were calculated when breed was an important fixed effect, using the random effect family(breed) as the error term. Most contrasts were nonsignificant ( > 0.10). Those that were significant ( < 0.05) included cholesterol concentration of subcutaneous (s.c.) adipose tissue (three-fourths Angus > F, three-fourths Brahman > F, and three-fourths crossbred progeny combined > F), s.c. adipocyte volume (three-fourths Angus > F and three-fourths bloods combined > F), lipogenesis from acetate in s.c. adipose tissue (three-fourths Brahman calves from Brahman dams > three-fourths Brahman calves from F dams), and percentage 18:3-3 in s.c. adipose tissue (three-fourths Brahman calves from Brahman-sired F dams < three-fourths Brahman calves from Angus-sired F dams). Intramuscular adipocyte volume ( < 0.001) was less in three-fourths Brahman cattle than in three-fourths Angus cattle. Additionally, several differences were observed in i.m. adipose tissue that were consistent with this being a less-developed adipose tissue in three-fourths Brahman cattle than in three-fourths Angus cattle.

Circadian rhythms control aspects of physiological events, including lipid metabolism, showing rhythmic fluctuation over 24 h. Therefore, it is not sufficient to evaluate thoroughly how dietary components regulate lipid metabolism with a single time-point assay. In the present study, a time-course study was performed to analyze the effect of sea cucumber saponin echinoside A (EA) on lipid metabolism over 24 h. Results showed that EA lowered the levels of TC and TG in both serum and liver at most time-points during the 24 h. Activities of hepatic lipogenic enzymes and lipolytic enzymes were inhibited and elevated respectively by EA to varied degrees at different time-points. Meanwhile, parallel variation trends of gene expression involved in fatty acid synthesis and β-oxidation were observed accordingly. The interaction between EA and lipid metabolism showed a time-dependent effect. Overall, EA impaired fatty acid synthesis and enhanced mitochondrial fatty acid β-oxidation in ad libitum feeding over 24 h.

The link between dietary carbohydrate/protein and de novo lipogenesis (DNL) remains debatable in carnivorous fish. We aimed to evaluate and compare the response of hepatic lipogenic gene expression to dietary carbohydrate intake/glucose and dietary protein intake/amino acids (AAs) during acute stimulations using both in vivo and in vitro approaches. For the in vivo trial, three different diets and a controlled-feeding method were employed to supply fixed amount of dietary protein or carbohydrate in a single meal; for the in vitro trial, primary hepatocytes were stimulated with a low or high level of glucose (3 mM or 20 mM) and a low or high level of AAs (one-fold or four-fold concentrated AAs). In vitro data showed that a high level of AAs upregulated the expression of enzymes involved in DNL [fatty acid synthase (FAS) and ATP citrate lyase (ACLY)], lipid bioconversion [elongation of very long chain fatty acids like-5 (Elovl5), Elovl2, Δ6 fatty acyl desaturase (D6D) and stearoyl-CoA desaturase-1 (SCD1)], NADPH production [glucose-6-phosphate dehydrogenase (G6PDH) and malic enzyme (ME)], and transcriptional factor sterol regulatory element binding protein 1-like, while a high level of glucose only elevated the expression of ME. Data in trout liver also showed that high dietary protein intake induced higher lipogenic gene expression (FAS, ACLY, and Elovl2) regardless of dietary carbohydrate intake, while high carbohydrate intake markedly suppressed the expression of acetyl-CoA carboxylase (ACC) and Elovl5. Overall, we conclude that, unlike rodents or humans, hepatic fatty acid biosynthetic gene expression in rainbow trout is more responsive to dietary protein intake/AAs than dietary carbohydrate intake/glucose during acute stimulations. This discrepancy probably represents one important physiological and metabolic difference between carnivores and omnivores., (Copyright © 2016 the American Physiological Society.)

Background & Aims: CD147 is a transmembrane glycoprotein which is highly expressed in various human cancers including hepatocellular carcinoma (HCC). A drug Licartin developed with (131)Iodine-labeled antibody against CD147 has been approved by the Chinese Food and Drug Administration (FDA) and enters into clinical use for HCC treatment. Increasing lines of evidence indicate that CD147 is implicated in the metabolism of cancer cells, especially glycolysis. However, the molecular mechanism underlying the relationship between CD147 and aberrant tumor lipid metabolism remains elusive., Methods: We systematically investigated the role of CD147 in the regulation of lipid metabolism, including de novo lipogenesis and fatty acid β-oxidation, in HCC cells and explored the underlying molecular mechanisms., Results: Bioinformatic analysis and experimental evidence demonstrated that CD147 significantly contributed to the reprogramming of fatty acid metabolism in HCC cells mainly through two mechanisms. On one hand, CD147 upregulated the expression of sterol regulatory element binding protein 1c (SREBP1c) by activating the Akt/mTOR signaling pathway, which in turn directly activated the transcription of major lipogenic genes FASN and ACC1 to promote de novo lipogenesis. On the other hand, CD147 downregulated peroxisome proliferator-activated receptor alpha (PPARα) and its transcriptional target genes CPT1A and ACOX1 by activating the p38 MAPK signaling pathway to inhibit fatty acid β-oxidation. Moreover, in vitro and in vivo assays indicated that the CD147-mediated reprogramming of fatty acid metabolism played a critical role in the proliferation and metastasis of HCC cells., Conclusion: Our findings demonstrate that CD147 is a critical regulator of fatty acid metabolism, which provides a strong line of evidence for this molecule to be used as a drug target in cancer treatment., (Copyright © 2015 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.)

Fatty acid and fat synthesis in the liver is a highly regulated metabolic pathway that is important for very low-density lipoprotein (VLDL) production and thus energy distribution to other tissues. Having common features at their promoter regions, lipogenic genes are coordinately regulated at the transcriptional level. Transcription factors, such as upstream stimulatory factors (USFs), sterol regulatory element-binding protein 1C (SREBP1C), liver X receptors (LXRs) and carbohydrate-responsive element-binding protein (ChREBP) have crucial roles in this process. Recently, insights have been gained into the signalling pathways that regulate these transcription factors. After feeding, high blood glucose and insulin levels activate lipogenic genes through several pathways, including the DNA-dependent protein kinase (DNA-PK), atypical protein kinase C (aPKC) and AKT-mTOR pathways. These pathways control the post-translational modifications of transcription factors and co-regulators, such as phosphorylation, acetylation or ubiquitylation, that affect their function, stability and/or localization. Dysregulation of lipogenesis can contribute to hepatosteatosis, which is associated with obesity and insulin resistance.

Despite the impaired intestinal lipid absorption and low level of visceral fat, the Sod1-deficient mouse is susceptible to developing liver steatosis. To gain insights into the mechanism responsible for this abnormal lipid metabolism, we analyzed primary cultured hepatocytes obtained from Sod1-deficient and wild-type mice. Lipid droplets began to accumulate in the cultured hepatocytes and was further increased by a Sod1 deficiency. Levels of enzymes involved in lipogenesis were elevated. It thus appears that lipogenesis is activated by oxidative stress, which is more prominent in the case of Sod1 deficiency, and appears to participate in liver steatosis., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Aim: Monoacyglycerol acyltransferases (MGATs) are known to play important roles in intestinal TG absorption. In contrast, the role of MGATs in the liver is still unclear. We investigated the effects of JTP-103237, a novel MGAT inhibitor, on hepatic MGAT activity and hepatic lipid metabolism., Results: JTP-103237 reduced hepatic triglyceride content and hepatic MGAT activity in a high sucrose very low fat (HSVLF) diet induced fatty liver model. Interestingly, JTP-103237 suppressed not only triglyceride (TG) and diacylglycerol (DG) synthesis, but also fatty acid (FA) synthesis (de novo lipogenesis) in this model. JTP-103237 also suppressed lipogenesis-related gene expression, such as sterol regulatory element-binding protein 1-c. Moreover, JTP-103237 decreased plasma glucose levels and total cholesterol and reduced the accumulation of epididymal fats in HSVLF diet fed mice., Conclusion: In the present study, JTP-103237 prevented carbohydrate-induced fatty liver and suppressed both TG synthesis and de novo lipogenesis, suggesting MGAT inhibitor may prevent carbohydrate-induced metabolic disorders, including NAFLD, obesity and diabetes., (Copyright © 2015 The Authors. Production and hosting by Elsevier B.V. All rights reserved.)

Bacterial type II fatty acid synthesis (FASII) is a target for the development of novel therapeutics. Bacteria incorporate extracellular fatty acids into membrane lipids, raising the question of whether pathogens use host fatty acids to bypass FASII and defeat FASII therapeutics. Some pathogens suppress FASII when exogenous fatty acids are present to bypass FASII therapeutics. FASII inhibition cannot be bypassed in many bacteria because essential fatty acids cannot be obtained from the host. FASII antibiotics may not be effective against all bacteria, but a broad spectrum of Gram-negative and -positive pathogens can be effectively treated with FASII inhibitors., (© 2015 by The American Society for Biochemistry and Molecular Biology, Inc.)

Ovarian hormone loss is associated with a shift in fat distribution to intra-abdomin al adipose tissue (intra-AAT) depots and with lipid metabolism disorders, which predisposes individuals to developing insulin resistance. Resistance training (RT) prevents increases in intra-AAT after ovarian hormone loss. However, the molecular mechanisms underlying these changes remain unclear. We investigated the effects of ovariectomy and RT on gene expression related to lipogenesis and fat oxidation in the intra-AAT of ovariectomized rats. Sprague-Dawley rats (n=6/group) were divided into the groups: sham-sedentary, ovariectomized-sedentary, sham-RT and ovariectomized-RT. RT groups performed a 10-week climbing program on a ladder with progressive overload. Intra-AAT was subjected to morphometric and mRNA analysis. Ovariectomized-sedentary group had larger adipocytes and higher expression of peroxisome proliferator-activated receptor-γ (PPAR-γ), sterol regulatory element-binding protein-1c (SREBP-1c), stearoyl-CoA desaturase-1 (SCD-1), acetyl-CoA carboxylase (ACC), hormone-sensitive lipase (HSL) and lower expression of the oxidative carnitinepalmitoyltransferase-I (CPT-1). RT counteracted OVX-induced increases in PPAR-γ and SCD-1 and decreased SREBP-1c. ACC and HSL were downregulated in ovariectomized-RT compared with the ovariectomized-sedentary group. Ovariectomized-RT group had the highest CPT-1 gene expression. Adipocyte size decreased in ovariectomized-RT group. Results suggest that RT reduces intra-AAT adipocyte size in ovariectomized rats by suppressing intra-AAT fatty acid synthesis and enhancing fatty acid β-oxidation., (© Georg Thieme Verlag KG Stuttgart · New York.)

Previous work has demonstrated that elevated maternal lipid intake (particularly from dairy products) is associated with increased lipids and altered fatty acid profile in milk produced by healthy lactating women. To investigate our primary hypothesis that a maternal diet rich in full-fat dairy products would simultaneously increase milk lipid percent and expression of genes related to the uptake and/or de novo biosynthesis of milk lipids, we provided 15 lactating women with diets enriched in full-fat or nonfat dairy products for 14 days each in a randomized, crossover study with a 2-week washout period. Milk fat (%) was lower when women consumed the low-fat compared with the full-fat dairy diet (2.41% ± 0.31% vs 3.35% ± 0.28%, respectively; P < .05); concentrations of more than 20 fatty acids also differed. However, neither conservatively evaluated microarray data nor quantitative real-time polymerase chain reaction analysis uncovered any treatment effects on expression of genes related to lipid synthesis or uptake. These data suggest that alteration in gene expression in the lactating human mammary gland is likely not the primary mechanism by which consumption of a high-fat diet affects milk fat percent in healthy, lactating women., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Hepatic steatosis is associated with detrimental metabolic phenotypes including enhanced risk for diabetes. Stearoyl-CoA desaturases (SCDs) catalyze the synthesis of MUFAs. In mice, genetic ablation of SCDs reduces hepatic de novo lipogenesis (DNL) and protects against diet-induced hepatic steatosis and adiposity. To understand the mechanism by which hepatic MUFA production influences adipose tissue stores, we created two liver-specific transgenic mouse models in the SCD1 knockout that express either human SCD5 or mouse SCD3, that synthesize oleate and palmitoleate, respectively. We demonstrate that hepatic de novo synthesized oleate, but not palmitoleate, stimulate hepatic lipid accumulation and adiposity, reversing the protective effect of the global SCD1 knockout under lipogenic conditions. Unexpectedly, the accumulation of hepatic lipid occurred without induction of the hepatic DNL program. Changes in hepatic lipid composition were reflected in plasma and in adipose tissue. Importantly, endogenously synthesized hepatic oleate was associated with suppressed DNL and fatty acid oxidation in white adipose tissue. Regression analysis revealed a strong correlation between adipose tissue lipid fuel utilization and hepatic and adipose tissue lipid storage. These data suggest an extrahepatic mechanism where endogenous hepatic oleate regulates lipid homeostasis in adipose tissues.