Development of the novel ACLY inhibitor 326E as a promising treatment for hypercholesterolemia

Hepatic cholesterol accumulation is an important contributor to hypercholesterolemia, which results in atherosclerosis and cardiovascular disease (CVD). ATP-citrate lyase (ACLY) is a key lipogenic enzyme that converts cytosolic citrate derived from tricarboxylic acid cycle (TCA cycle) to acetyl-CoA in the cytoplasm. Therefore, ACLY represents a link between mitochondria oxidative phosphorylation and cytosolic de novo lipogenesis. In this study, we developed the small molecule 326E with an enedioic acid structural moiety as a novel ACLY inhibitor, and its CoA-conjugated form 326E-CoA inhibited ACLY activity with an IC50 = 5.31 ± 1.2 μmol/L in vitro. 326E treatment reduced de novo lipogenesis, and increased cholesterol efflux in vitro and in vivo. 326E was rapidly absorbed after oral administration, exhibited a higher blood exposure than that of the approved ACLY inhibitor bempedoic acid (BA) used for hypercholesterolemia. Chronic 326E treatment in hamsters and rhesus monkeys resulted in remarkable improvement of hyperlipidemia. Once daily oral administration of 326E for 24 weeks prevented the occurrence of atherosclerosis in ApoE-/- mice to a greater extent than that of BA treatment. Taken together, our data suggest that inhibition of ACLY by 326E represents a promising strategy for the treatment of hypercholesterolemia.

Effect of Yin Yang protein 1 transcriptionally regulating acetyl-CoA carboxylase 1 on the cell migration and lipogenesis in ovarian cancer / 肿瘤研究与临床

Objective:To investigate the expression of acetyl-CoA carboxylase 1 (ACC1) in ovarian cancer tissues and cells, and the related mechanisms of the effect of ACC1 on cell migration and lipogenesis in ovarian cancer.Methods:Samples including 1 case of normal ovarian tissue, 1 case of ovarian cancer primary lesion tissue and 1 case of ovarian cancer omentum metastatic tissue diagnosed by pathology examination of patients undergoing surgery resection who admitted to Linyi Cancer Hospital between January 2019 and December 2021 were collected. Immunohistochemistry was used to detect the protein levels of ACC1 and Yin Yang protein 1 (YY1) of all tissues. The PROMO database was used to predict the possible binding sites of YY1 and ACC1 promoter region. Through the assembled viral vector, the HEY cells of human ovarian cancer with ACC1 or YY1 expression [the untreated cells were treated as the negative control (NC)], or knocked down ACC1 or YY1 (the interference sequence sh1, sh2, sh3 was transferred to the target gene, and the negative control sequence shNC was transferred to the interference sequence). Double luciferase reporter gene assay was used to verify the binding sites of YY1 and ACC1 promoter and the activity of transcriptional regulation. Real-time fluorescence quantitative polymerase chain reaction (qRT-PCR) and Western blot were used to detect the mRNA and protein expression levels of ACC1 and YY1 in the treated HEY cells, respectively. Transwell assay was used to detect the migration ability of HEY cells. Oil red O staining and Nile red staining were used to detect the lipid droplets in HEY cells.Results:The immunohistochemical scores of ACC1 and YY1 were 0, 2, 8 scores and 0, 4, 6 scores, respectively in normal ovarian tissue, primary lesion of ovarian cancer, and omentum metastatic tissue. Transwell assay showed that the number of invasive HEY cells in ACC1 overexpression group was more than that in NC group [(87.7±7.4) vs. (52.2±4.2), t = 5.19, P = 0.003]. The number of invasive HEY cells in ACC1-sh1 group, and ACC1-sh2 group with the knockdown of ACC1 was less than that in shNC group [(21.2±1.5), (29.7±2.3) vs. (56.2±5.3); t value was 6.41, 3.77; P < 0.001, P < 0.005]. The number of lipid droplets in HEY cells in the ACC1 overexpression group was more than that in the control NC group [Oil red O staining: (301±25) vs. (215±21); Nile red staining: (287±15) vs. (207±10); all P < 0.05]; the number of lipid droplets in HEY cells in ACC1-sh1 and ACC1-sh2 group with the knockdown of ACC1 was less than that in ACC1-shNC group [Oil red O staining: (113±8), (119±12) vs. (195±18); Nile red staining: (82±8), (117±11) vs. (165±17); all P < 0.05]. The result of dual luciferase reporter assay showed that overexpression of YY1 promoted the luciferase activity of the wild type ACC1 promoter region report gene ( P = 0.003), while the luciferase activity of the report gene was inhibited compared with the wild type after the mutation of binding sites of YY1 in ACCI promoter region ( P = 0.008). Western blot results showed that the expression levels of YY1 and ACC1 protein in HEY cells with YY1 overexpression group were higher than those in NC group, which indicated a synergistic increasing trend of both YY1 and ACC1; the expression levels of YY1 and ACC1 protein in YY1-sh1 group, YY1-sh2 group and YY1-sh3 group with the knockdown of YY1 were lower than those in the control YY1-shNC group, which indicated a synergistic decreasing trend of both YY1 and ACC1. Conclusions:ACC1 and YY1 are highly expressed in ovarian cancer metastatic tissues and both show a positive correlation trend. The expression level of ACC1 in vitro has an impact on cell migration and lipogenesis in ovarian cancer via YY1 transcriptionally regulating ACC1.

Hipertrofia y resistencia a la insulina en un modelo in vitro de obesidad y DMT2 inducida por alta glucosa e insulina / Hypertrophy and insulin resistance in an in vitro model of obesity and T2DM induced by high glucose and insulin

Resumen Introducción: La obesidad es considerada un factor de riesgo para desarrollar resistencia a la insulina. La expansión del tejido adiposo se ha relacionado con el aumento de la producción de citoquinas proinflamatorias que, junto a los ácidos grasos son responsables, al menos en parte, del desarrollo de la resistencia a la insulina y esta a su vez, facilita el desarrollo de diabetes mellitus tipo 2 (DMT2). Objetivo: El propósito de este estudio fue realizar y caracterizar un modelo in vitro de obesidad empleando concentraciones altas de glucosa e insulina en una línea de células adipocitarias. Métodos: Se indujo modelo de hipertrofia celular realizando un estímulo en adipocitos maduros con una concentración de glucosa (450 mg/dL) e insulina (106 pmol/L) (modelo HGHI). Tras estímulo se realizaron ensayos de viabilidad celular, diámetro celular, movilización de lípidos y marcadores de señalización de insulina. Resultados: Tras el tratamiento con HGHI, se evidencia hipertrofia adipocitaria, incremento en la acumulación de lípidos, reducción de la ruptura de éstos, alteración de la señalización de insulina y tendencia a modificación de proteínas de marcadores de estrés de retículo y estrés oxidativo. Conclusión: Estos resultados demuestran la validez del modelo in vitro que simula al menos en parte la obesidad asociada a insulino resistencia, siendo una herramienta útil para estudiar los mecanismos de susceptibilidad a obesidad y resistencia a la insulina inducida in vitro con diferentes moléculas.

Abstract Introduction: Obesity is considered a risk factor for developing insulin resistance. The increase in adipose tissue has been related to the increase in the production of pro-inflammatory cytokines, which together with fatty acids are responsible, at least in part, for the development of insulin resistance, and this in turn facilitates the development of T2 diabetes mellitus type 2 (DMT2). Objective: The purpose of this study was to perform and characterize an in vitro model of obesity using high concentrations of glucose and insulin on an adipocyte cell line. Methods: A cell hypertrophy model was induced by stimulating mature adipocytes with a concentration of glucose (450 mg/dL) and insulin (106 pmol/L) (HGHI model). The cell viability, cell diameter, lipid mobilization and insulin signalling markers were evaluated. Results: After HGHI treatment, adipocytes show hypertrophy, increase in lipid accumulation, reduction of lipid breakdown, alteration of insulin signalling, a tendency to modify proteins of reticulum stress markers and, oxidative stress. Conclusion: These results demonstrate a new in vitro model that simulates, at least in part, obesity associated with insulin resistance being a useful tool to study the mechanisms of susceptibility to obesity and insulin resistance induced in vitro by different molecules.

A novel inhibitor of N 6-methyladenosine demethylase FTO induces mRNA methylation and shows anti-cancer activities

N 6-methyladenosine (m6A) modification is critical for mRNA splicing, nuclear export, stability and translation. Fat mass and obesity-associated protein (FTO), the first identified m6A demethylase, is critical for cancer progression. Herein, we developed small-molecule inhibitors of FTO by virtual screening, structural optimization, and bioassay. As a result, two FTO inhibitors namely 18077 and 18097 were identified, which can selectively inhibit demethylase activity of FTO. Specifically, 18097 bound to the active site of FTO and then inhibited cell cycle process and migration of cancer cells. In addition, 18097 reprogrammed the epi-transcriptome of breast cancer cells, particularly for genes related to P53 pathway. 18097 increased the abundance of m6A modification of suppressor of cytokine signaling 1 (SOCS1) mRNA, which recruited IGF2BP1 to increase mRNA stability of SOCS1 and subsequently activated the P53 signaling pathway. Further, 18097 suppressed cellular lipogenesis via downregulation of peroxisome proliferator-activated receptor gamma (PPARγ), CCAAT/enhancer-binding protein alpha (C/EBPα), and C/EBPβ. Animal studies confirmed that 18097 can significantly suppress in vivo growth and lung colonization of breast cancer cells. Collectively, we identified that FTO can work as a potential drug target and the small-molecule inhibitor 18097 can serve as a potential agent against breast cancer.

Effects of oleic (18: 1n-9) and palmitic (16: 0) fatty acids on the metabolic state of adipocytes / Efectos de los ácidos grasos oleico (18: 1n-9) y palmítico (16: 0) en el estado metabólico del adipocito

Abstract Background: Elevated serum-free fatty acid (FFA) levels induce insulin resistance (IR) or a protective mechanism to IR development in humans; it depends on FFA type. Objetive: This study explores the effects of oleic (OLA - unsatured) and palmitic (PAM - saturated) fatty acids on insulin action in mature adipocytes effect. Methods: Cells were incubated 18 h with or without OLA and PAM at 250 μM, and 500 μM. After the culture period, were measured: adipocyte viability, size, fatty acids mobilisation, insulin signalling proteins, and glucose uptake. Results: Adipocytes exhibited optimal viability tolerances regardless of the kinds of fatty acids used for treatment. However, adipocytes were hypertrophic after OLA and PAM stimuli. Additionally, lipogenesis (lipid synthesis), and lipolysis (lipid breakdown) were significantly increased by treatment with OLA, or PAM (500 μM) compared to control. Moreover, OLA results showed that there was no significant reduction in signalling cascades, except for a downstream proinflammatory response. Instead, PAM hypertrophic adipocytes were insulin resistant with alteration of proinflammatory and stress markers. Conclusions: Current findings suggest that PAM induces insulin resistance, mitochondrial and reticulum stress on fat cells compared to those treated with OLA that, protects adipocytes to all those alterations.

Resumen Introducción: Los niveles elevados de ácidos grasos libres (AGL) en suero inducen resistencia a insulina (RI) o un mecanismo de protección del desarrollo de RI en humanos, esto depende del tipo de AGL. Objetivo: Este estudio explora los efectos de los ácidos grasos oleico (insaturados - OLA) y palmítico (saturados - PAM) sobre la insulina en adipocitos maduros. Métodos: Las células se incubaron 18 h con o sin OLA y PAM a 250 μM y 500 μM. Después del período de cultivo, se evaluó en adipocitos: viabilidad, tamaño, movilización de ácidos grasos, proteínas de señalización de insulina y absorción de glucosa. Resultados: Los adipocitos mostraron viabilidad óptima independientemente de los tipos de ácidos grasos utilizados en el tratamiento. Los adipocitos eran hipertróficos tras estimulo con OLA y PAM. La lipogénesis (síntesis de lípidos) y la lipólisis (degradación de lípidos) aumentaron significativamente con el tratamiento con OLA o PAM (500 μM) en comparación con el control. En los resultados de OLA no se evidenció una reducción significativa en las cascadas de señalización de insulina, a excepción de una respuesta proinflamatoria posterior. En cambio, los adipocitos hipertróficos tratados con PAM presentaron resistencia a la insulina y alteración de los marcadores proinflamatorios y de estrés. Conclusiones: Nuestros hallazgos sugieren que PAM induce resistencia a la insulina, estrés mitocondrial y del retículo en las células grasas en comparación con aquellos tratados con OLA, AGL que, en cambio, protegen a los adipocitos de todas esas alteraciones.

Fructosa, un factor clave modificable en la patogenia del síndrome metabólico, la esteatosis hepática y la obesidad / Fructose, a modifiable key factor in the pathogenic basis of metabolic syndrome, NAFLD and obesity / Frutose, um fator chave modificável na patogênese da síndrome metabólica, esteatose hepática e obesidade

Resumen: En esta revisión se resume el rol específico que el exceso de consumo de fructosa más allá de sus calorías puede tener en el desarrollo del síndrome metabólico, la esteatosis hepática no alcohólica y su asociación con la obesidad. Se desglosan los efectos de la fructosa (en comparación con la glucosa) en la esteatosis hepática, lo que genera la insulino-resistencia y la hipertrigliceridemia. Por su metabolismo hepático mayoritario y la falta de regulación, los flujos altos de fructosa consumen ATP generando ácido úrico, producen metabolitos tóxicos, como ceramidas y metilglioxal, y activan la síntesis de lípidos. Además, se analizan los efectos en el tejido adiposo, la activación del cortisol y las hormonas involucradas en el control de la saciedad, todas las cuales se ven afectadas por el consumo de fructosa. La insulino-resistencia hepática inicial se complica con insulino-resistencia sistémica, que genera leptino-resistencia y un ciclo de hiperfagia. Estos resultados subrayan la necesidad de intervenciones clínicas y educativas dentro de la población para regular o reducir el consumo de fructosa, especialmente en niños y adolescentes, sus principales consumidores.

Summary: This review summarizes the specific role that excess fructose consumption (beyond its calories) may have in the development of MetS, NAFLD and its association with obesity. The effects of fructose (compared to glucose) on hepatic steatosis are discussed as well as their consequence: insulin resistance and hypertriglyceridemia. Unlike glucose, more than 80% ingested fructose stays in the liver, and due to lack of fine metabolic regulation, high fructose flows consume ATP generating uric acid, produce toxic metabolites such as ceramides and methylglyoxal and activate lipid synthesis. In addition, the study analyzes the effects of fructose on adipose tissue, cortisol activation and hormones involved in satiety control, all of which are affected by fructose consumption. The initial hepatic insulin resistance is complicated by systemic insulin resistance, which generates leptin resistance and a hyperphagia cycle. These results underscore the need for clinical and educational interventions within the population to regulate / reduce fructose consumption, especially in children and adolescents, their main consumers.

Resumo: No momento vivemos uma pandemia causada pelo vírus SARS-CoV-2, COVID-19, sendo o mais recomendado ficar em casa para reduzir o contágio e que este seja reduzido ao mínimo possível. No século 21, a tecnologia está mais presente do que nunca e faz parte do nosso dia a dia. Tendo em vista que há significativo abuso da mesma, principalmente por adolescentes, na nossa perspectiva que promove o movimento e a redução do comportamento sedentário, propomos o uso de videogames ativos em substituição aos videogames convencionais. Para isso, fizemos uma revisão dos principais benefícios que estas podem trazer, tanto para a população mais jovem como para os idosos. Esta última faixa etária é uma das mais afetadas pela pandemia e, portanto, há uma forte recomendação para que fiquem em casa. No entanto, é recomendável usá-lo com responsabilidade e não investir tempo excessivo que possa causar danos.

Single cell oil production by a novel yeast Trichosporon mycotoxinivorans for complete and ecofriendly valorization of paddy straw

Background: Oleaginous yeasts can be grown on different carbon sources, including lignocellulosic hydrolysate containing a mixture of glucose and xylose. However, not all yeast strains can utilize both the sugars for lipogenesis. Therefore, in this study, efforts were made to isolate dual sugar-utilizing oleaginous yeasts from different sources. Results: A total of eleven isolates were obtained, which were screened for their ability to utilize various carbohydrates for lipogenesis. One promising yeast isolate Trichosporon mycotoxinivorans S2 was selected based on its capability to use a mixture of glucose and xylose and produce 44.86 ± 4.03% lipids, as well as its tolerance to fermentation inhibitors. In order to identify an inexpensive source of sugars, nondetoxified paddy straw hydrolysate (saccharified with cellulase), supplemented with 0.05% yeast extract, 0.18% peptone, and 0.04% MgSO4 was used for growth of the yeast, resulting in a yield of 5.17 g L−1 lipids with conversion productivity of 0.06 g L−1 h−1 . Optimization of the levels of yeast extract, peptone, and MgSO4 for maximizing lipid production using Box­Behnken design led to an increase in lipid yield by 41.59%. FAME analysis of single cell oil revealed oleic acid (30.84%), palmitic acid (18.28%), and stearic acid (17.64%) as the major fatty acids. Conclusion: The fatty acid profile illustrates the potential of T. mycotoxinivorans S2 to produce single cell oil as a feedstock for biodiesel. Therefore, the present study also indicated the potential of selected yeast to develop a zero-waste process for the complete valorization of paddy straw hydrolysate without detoxification

Advances in molecular mechanisms for enhanced hepatic lipogenesis in insulin resistance / 药学学报

Hepatic selective insulin resistance refers to that insulin fails to suppress hepatic glucose production but continues to promote hepatic lipogenesis in insulin resistance. Therefore, type 2 diabetes mellitus is characterized with dyslipidemia apart from hyperglycemia. This review highlights the roles and molecular mechanisms of the key hepatic lipogenesis factors such as sterol regulatory factor binding protein 1c (SREBP1c), mammalian rapamycin target complex 1 (mTORC1), endoplasmic reticulum stress (ER stress), FoxO1, lipid synthesis substrate, etc.

El Sistema de Endocannabinoides como regulador de la lipogénesis y su posible modulación por la Mangiferina

RESUMEN Actualmente es innegable la participación del sistema endocannabinoides (SEC) en la regulación metabólica; ya que su sobre estimulación ha sido relacionada con varias patologías entre las que se encuentran obesidad, diabetes mellitus, retinopatía e hígado graso no alcohólico. Éstas se relacionan mutuamente a través de alteraciones del metabolismo de los lípidos, como lo es una sobre estimulación de la síntesis de ácidos grasos, una disminución en la beta-oxidación, hiperglicemia causada por un aumento de la gluconeogénesis, así como en la glucólisis; procesos en los cuales se ha descrito al SEC como un participante crucial. Por otro lado, algunos compuestos fitoquímicos, tales como la mangiferina (MGF), han probado sus efectos farmacológicos en el metabolismo de lípidos a nivel hepático y en el control glicémico. Hasta el momento se desconoce el efecto de la mangiferina sobre los receptores de endocannabinoides, por lo que esta revisión aborda la regulación a nivel sistémico (órganos y tejidos) y central (sistema nervioso) de la lipogénesis por el SEC y la regulación negativa que tiene la mangiferina sobre éste. Finalmente se sugiere, con base en la información publicada hasta el momento, una relación entre el posible efecto que pueden tener la MGF sobre el SEC.

ABSTRACT Currently, the participation of the endocannabinoid system in metabolic regulation is undeniable; because its hyperactivation has been related to several pathologies such as obesity, diabetes mellitus, retinopathy and non-alcoholic fatty liver, and others. These pathologies are related through alterations in lipid metabolism, e.g. over stimulation of fatty acid synthesis, beta-oxidation decrease, hyperglycemia increase, all these changes are caused by increase in gluconeogenesis, as well as glycolysis, processes in which the SEC has been described as a main character. On the other hand, some phytochemicals such as mangiferin (MGF) have shown their pharmacological effects on lipid metabolism, as well as glycemic control. So far, the effect of mangiferin on cannabinoid receptors is unknown. In this review, we try to demonstrate how mangiferin and these receptors participate in the opposite manner in the adaptation of lipid metabolism in many organs like as liver, tissue adipose and SN (nervous system). In addition, we suggest, based on the published information to until now, a relationship between the MGF´s effect on the SEC.

In Silico Characterization and Expression Analysis Of The Alpha Subunit Of The Heteromeric Acetyl-Coenzyme A Carboxylase From Two Microalgae / Caracterización in silico y análisis de la expresión de la subunidad alfa de la acetil-coenzima a carboxilasa heteromérica de dos microalgas

RESUMEN Las microalgas son microorganismos fotosintéticos con gran potencial para abastecer las demandas energéticas mundiales. Sin embargo, los limitados conocimientos que se tienen de estos organismos, en particular a nivel molecular de los procesos metabólicos, han limitado su uso con estos propósitos. En esta investigación se ha realizado el análisis in silico de la subunidad alfa de la acetil-Coenzima A carboxilasa heteromérica (αACCasa), una enzima clave en la biosíntesis de lípidos de las microalgas Chlorella sp. y Scenedesmus sp. Asimismo, se ha medido la expresión de este gen en ambas especies cultivadas en medios deficientes de nitrógeno. Los resultados indican que la αACCasa muestra conservación estructural y funcional en ambas especies de microalgas y su mayor similitud genética con otras especies de microalgas. Asimismo, se ha mostrado que el nivel de expresión del gen se incrementa significativamente cuando las microalgas son cultivadas en ausencia de nitrógeno, lo cual se relaciona a su vez con una mayor acumulación de lípidos microalgales. En conclusión, el análisis in silico de la αACCasa de Chlorella sp. y Scenedesmus sp. presentan características estructurales, funcionales y evolutivas muy similares con otras especies de microalgas y plantas. Asimismo, el estudio revela que en ambas especies el gen se sobreexpresa cuando las microalgas son sometidas a estrés por deficiencia de nitrógeno, el cual se relaciona significativamente con la acumulación de lípidos totales en estas células.

ABSTRACT Microalgae are photosynthetic microorganisms with great potential to supply the world's energy demands. However, the limited knowledge of these organisms, particularly at the molecular level of metabolic processes, has limited their use to these purposes. In this investigation, the in silico analysis of the alpha subunit of the heteromeric acetyl-coenzyme A carboxylase (αACCase), a key enzyme in lipid biosynthesis of microalgae Chlorella sp. and Scenedesmus sp. was carried out. Also, the expression of this gene has been measured in both species cultivated in nitrogen-depleted media. Results indicate that αACCase shows structural and functional conservation in both species of microalgae and their greater genetic similarity with other species of microalgae. Also, it has been shown that the expression levels of this gene are significantly increased when the microalgae are cultured in the absence of nitrogen, which in turn is related to a greater accumulation of microalgal lipids. In conclusion, the in silico analysis of the Chlorella sp. and Scenedesmus sp. αACCase reveals structural, functional and evolutionary characteristics very similar to other microalgae and plant species. Also, the study reveals that in both species the gene is overexpressed when microalgae are subjected to nitrogen deficiency stress, which is significantly related to total lipids accumulation in these cells.

Free fatty acid-induced histone acetyltransferase activity accelerates lipid accumulation in HepG2 cells

BACKGROUND/OBJECTIVES: Non-alcoholic fatty liver disease (NAFLD) is a common metabolic disease triggered by epigenetic alterations, including lysine acetylation at histone or non-histone proteins, affecting the stability or transcription of lipogenic genes. Although various natural dietary compounds have anti-lipogenic effects, their effects on the acetylation status and lipid metabolism in the liver have not been thoroughly investigated. MATERIALS/METHODS: Following oleic-palmitic acid (OPA)-induced lipid accumulation in HepG2 cells, the acetylation status of histone and non-histone proteins, HAT activity, and mRNA expression of representative lipogenic genes, including PPARγ, SREBP-1c, ACLY, and FASN, were evaluated. Furthermore, correlations between lipid accumulation and HAT activity for 22 representative natural food extracts (NExs) were evaluated. RESULTS: Non-histone protein acetylation increased following OPA treatment and the acetylation of histones H3K9, H4K8, and H4K16 was accelerated, accompanied by an increase in HAT activity. OPA-induced increases in the mRNA expression of lipogenic genes were down-regulated by C-646, a p300/CBP-specific inhibitor. Finally, we detected a positive correlation between HAT activity and lipid accumulation (Pearson's correlation coefficient = 0.604) using 22 NExs. CONCLUSIONS: Our results suggest that NExs have novel applications as nutraceutical agents with HAT inhibitor activity for the prevention and treatment of NAFLD.

Effects of Brassica oleracea extract on impaired glucose and lipid homeostasis in high-fat diet-induced obese mice

Objective: To examine the effect of Brassica oleracea extract (BO) on impaired glucose and lipid homeostasis in high-fat diet (HFD)-induced obese mice. Methods: Obesity of ICR mice was induced by feeding a HFD (45 kcal％ lard fat) for 16 weeks. During the last 8 weeks of study period, obese mice were additionally administered with BO (100 and 200 mg/kg/day). The metabolic parameters were determined. The gene expressions of hepatic lipogenesis were also studied. Results: After 8 weeks of treatment, BO (100 and 200 mg/kg) significantly reduced hyperglycemia and improved insulin sensitivity (P < 0.05). The serum lipid (total cholesterol, triglyceride, and non-esterified fatty acid) and hepatic triglyceride and non-esterified fatty acid were decreased (P < 0.05). The levels of insulin and leptin in serum were also decreased (P < 0.05). Moreover, the expressions of hepatic lipogenic genes including sterol regulatory element-binding protein 1c, fatty acid synthase, and acetyl-CoA carboxylase were decreased by BO treatment (P < 0.05). Conclusions: These results suggest that BO is a new therapeutic agent for improving the homeostasis of glucose and lipid in HFD-induced obese mice probably by suppression of lipogenic genes in liver tissue.

Effects of Brassica oleracea extract on impaired glucose and lipid homeostasis in high-fat diet-induced obese mice

Objective: To examine the effect of Brassica oleracea extract (BO) on impaired glucose and lipid homeostasis in high-fat diet (HFD)-induced obese mice. Methods: Obesity of ICR mice was induced by feeding a HFD (45 kcal% lard fat) for 16 weeks. During the last 8 weeks of study period, obese mice were additionally administered with BO (100 and 200 mg/kg/day). The metabolic parameters were determined. The gene expressions of hepatic lipogenesis were also studied. Results: After 8 weeks of treatment, BO (100 and 200 mg/kg) significantly reduced hyperglycemia and improved insulin sensitivity (P < 0.05). The serum lipid (total cholesterol, triglyceride, and non-esterified fatty acid) and hepatic triglyceride and non-esterified fatty acid were decreased (P < 0.05). The levels of insulin and leptin in serum were also decreased (P < 0.05). Moreover, the expressions of hepatic lipogenic genes including sterol regulatory element-binding protein 1c, fatty acid synthase, and acetyl-CoA carboxylase were decreased by BO treatment (P < 0.05). Conclusions: These results suggest that BO is a new therapeutic agent for improving the homeostasis of glucose and lipid in HFD-induced obese mice probably by suppression of lipogenic genes in liver tissue.

Efecto de la activación del receptor sensor de calcio sobre la expresión de genes lipogénicos en células HepG2 / Effect of calcium sensing receptor activation on lipogenic gene expression in HepG2 cells

Introduction: The Calcium Sensing Receptor (CaSR) is expressed in human fat cells, and its stimulation may be associated with adipose tissue dysfunction. The multisystemic character of obesity and the search of deepening the scope of the activation of CaSR in this disorder allows us to study the response of this protein in tissues that differ from adipose. Objective: To evaluate the effect of CaSR activation on the expression of lipogenic genes in a model of excess glucose and fatty acids in HepG2 human liver cells. Materials and methods: The effect of the calcimimetic cinacalcet (allosteric agonist of CaSR) on the content of triglycerides (fluorimetry) in a model of glucose supply and on the expression of lipogenic genes (qPCR) in hyperglycemia and hyperlipidemia conditions in the Liver cell line HepG2. Results: Cinacalcet, glucose (25 mM) and oleic acid (0.6 mM) did not affect cell viability. Activation of CaSR in the presence of glucose failed to increase the intracellular triglyceride content at 72 hours. Under these conditions, no response was observed for the factors coding for lipogenic genes (SREBP1c and FAS) at 24 hours of stimulation with cinacalcet in the liver cells. In the case of the over supply of fatty acids, the HepG2 cells did not show a variation in the gene expression of the DGAT enzymes after exposure to cinacalcet. Conclusion:Under conditions of glucose exposure, cinacalcet did not show a response in the triglyceride content, nor in the expression of genes related to hepatic lipogenesis. Therefore, stimulation of CaSR would not be associated with hepatic steatosis in HepG2 cells exposed to glucose.

Leucrose, a Sucrose Isomer, Suppresses Hepatic Fat Accumulation by Regulating Hepatic Lipogenesis and Fat Oxidation in High-fat Diet-induced Obese Mice

Obesity is currently one of the most serious public health problems and it can lead to numerous metabolic diseases. Leucrose, d-glucopyranosyl-α-(1-5)-d-fructopyranose, is an isoform of sucrose and it is naturally found in pollen and honey. The aim of this study was to investigate the effect of leucrose on metabolic changes induced by a high-fat diet (HFD) that lead to obesity. C57BL/6 mice were fed a 60% HFD or a HFD with 25% (L25) or 50% (L50) of its total sucrose content replaced with leucrose for 12 weeks. Leucrose supplementation improved fasting blood glucose levels and hepatic triglyceride content. In addition, leucrose supplementation reduced mRNA levels of lipogenesis-related genes, including peroxisome proliferator-activated receptor γ, sterol regulatory element binding protein 1C, and fatty acid synthase in HFD mice. Conversely, mRNA levels of β oxidation-related genes, such as carnitine palmitoyltransferase 1A and acyl CoA oxidase, returned to control levels with leucrose supplementation. Taken together, these results demonstrated the therapeutic potential of leucrose to prevent metabolic abnormalities by mediating regulation of plasma glucose level and hepatic triglyceride accumulation.

Inhibition of Serotonin Synthesis Induces Negative Hepatic Lipid Balance

BACKGROUND: Hepatic steatosis is caused by metabolic stress associated with a positive lipid balance, such as insulin resistance and obesity. Previously we have shown the anti-obesity effects of inhibiting serotonin synthesis, which eventually improved insulin sensitivity and hepatic steatosis. However, it is not clear whether serotonin has direct effect on hepatic lipid accumulation. Here, we showed the possibility of direct action of serotonin on hepatic steatosis. METHODS: Mice were treated with para-chlorophenylalanine (PCPA) or LP-533401 to inhibit serotonin synthesis and fed with high fat diet (HFD) or high carbohydrate diet (HCD) to induce hepatic steatosis. Hepatic triglyceride content and gene expression profiles were analyzed. RESULTS: Pharmacological and genetic inhibition of serotonin synthesis reduced HFD-induced hepatic lipid accumulation. Furthermore, short-term PCPA treatment prevented HCD-induced hepatic steatosis without affecting glucose tolerance and browning of subcutaneous adipose tissue. Gene expression analysis revealed that the expressions of genes involved in de novo lipogenesis and triacylglycerol synthesis were downregulated by short-term PCPA treatment as well as long-term PCPA treatment. CONCLUSION: Short-term inhibition of serotonin synthesis prevented hepatic lipid accumulation without affecting systemic insulin sensitivity and energy expenditure, suggesting the direct steatogenic effect of serotonin in liver.

Role of X-Box Binding Protein-1 in Fructose-Induced Lipogenesis in HepG2 Cells / 中华医学杂志(英文版)

<p><b>Background</b>A high consumption of fructose leads to hepatic steatosis. About 20-30% of triglycerides are synthesized via de novo lipogenesis. Some studies showed that endoplasmic reticulum stress (ERS) is involved in this process, while others showed that a lipotoxic environment directly influences ER homeostasis. Here, our aim was to investigate the causal relationship between ERS and fatty acid synthesis and the effect of X-box binding protein-1 (XBP-1), one marker of ERS, on hepatic lipid accumulation stimulated by high fructose.</p><p><b>Methods</b>HepG2 cells were incubated with different concentrations of fructose. Upstream regulators of de novo lipogenesis (i.e., carbohydrate response element-binding protein [ChREBP] and sterol regulatory element-binding protein 1c [SREBP-1c]) were measured by polymerase chain reaction and key lipogenic enzymes (acetyl-CoA carboxylase [ACC], fatty acid synthase [FAS], and stearoyl-CoA desaturase-1 [SCD-1]) by Western blotting. The same lipogenesis-associated factors were then evaluated after exposure of HepG2 cells to high fructose followed by the ERS inhibitor tauroursodeoxycholic acid (TUDCA) or the ERS inducer thapsigargin. Finally, the same lipogenesis-associated factors were evaluated in HepG2 cells after XBP-1 upregulation or downregulation through cell transfection.</p><p><b>Results</b>Exposure to high fructose increased triglyceride levels in a dose- and time-dependent manner and significantly increased mRNA levels of SREBP-1c and ChREBP and protein levels of FAS, ACC, and SCD-1, concomitant with XBP-1 conversion to an active spliced form. Lipogenesis-associated factors induced by high fructose were inhibited by TUDCA and induced by thapsigargin. Triglyceride level in XBP-1-deficient group decreased significantly compared with high-fructose group (4.41 ± 0.54 μmol/g vs. 6.52 ± 0.38 μmol/g, P < 0.001), as mRNA expressions of SREBP-1c (2.92 ± 0.46 vs. 5.08 ± 0.41, P < 0.01) and protein levels of FAS (0.53 ± 0.06 vs. 0.85 ± 0.05, P = 0.01), SCD-1 (0.65 ± 0.06 vs. 0.90 ± 0.04, P = 0.04), and ACC (0.38 ± 0.03 vs. 0.95 ± 0.06, P < 0.01) decreased. Conversely, levels of triglyceride (4.22 ± 0.54 μmol/g vs. 2.41 ± 0.35 μmol/g, P < 0.001), mRNA expression of SREBP-1c (2.70 ± 0.33 vs. 1.00 ± 0.00, P < 0.01), and protein expression of SCD-1 (0.93 ± 0.06 vs. 0.26 ± 0.05, P < 0.01), ACC (0.98 ± 0.09 vs. 0.43 ± 0.03, P < 0.01), and FAS (0.90 ± 0.33 vs. 0.71 ± 0.02, P = 0.04) in XBP-1s-upregulated group increased compared with the untransfected group.</p><p><b>Conclusions</b>ERS is associated with de novo lipogenesis, and XBP-1 partially mediates high-fructose-induced lipid accumulation in HepG2 cells through augmentation of de novo lipogenesis.</p>

Protection effect of ATF-4 knockdown on fructose-induced steatosis in HepG2 cells / 实用医学杂志

Objective To investigate he intervention effect of knockdown of activating transcription factor 4(ATF-4)on fructose-induced lipid accumulation in liver cells. Methods HepG2 cells were divided into the control group(C),high fructose group(F),high-fructose+negative control group(F+NC)and high-fructose+ATF-4 siRNA group(F+ATF-4-). The mRNA level of gens of the upstream transcriptional factors and ERS markers was detected. The protein level of ACC,FAS and SCD-1 was also detected. Results Compared with group C,the mRNA expression of SREBP-1c,ChREBP,GRP78 and CHOP was increased(P < 0.01),while ATF-4 knock-down decreased the expression of the above genes(P < 0.01 ,respectively). Compared with group C ,the protein expression of ACC,FAS and SCD-1 was increased in group F(P<0.01,respectively). While ATF-4 knockdown decreased the protein expression of ACC ,FAS and SCD-1. Conclusions ATF-4 knockdown can improve the lipid steatosis induced by fructose through down-regulating lipid lipogenesis ,indicating ATF-4 possesses a regulatory effect on lipogenesis.

Ethanol extract of Allium fistulosum inhibits development of non-alcoholic fatty liver disease

BACKGROUND/OBJECTIVES: Non-alcoholic fatty liver disease (NAFLD) is a leading cause of chronic liver disease and is closely associated with metabolic syndrome. In the present study, we observed the effect of ethanol extract of Allium fistulosum (EAF) on NAFLD and have suggested the possibility of using EAF as a natural product for application in the development of a treatment for NAFLD. MATERIALS/METHODS: The preventive effect on hepatic lipid accumulation was estimated by using an oleic acid (OA)-induced NAFLD model in vitro and a Western diet (high-fat high-sucrose; WD)-induced obese mouse model. Animals were divided into three groups (n = 7): normal diet group (ND), WD group, and WD plus 1% EAF group. RESULTS: EAF reduced OA-stimulated lipid accumulation in HepG2 cells in the absence of cellular cytotoxicity and significantly blocked transcriptional activation of sterol regulatory element-binding protein 1 and fatty acid synthase genes. Subsequently, we investigated these effects in vivo in mice fed either ND or WD in the presence or absence of EAF supplementation. In comparison to the ND controls, the WD-fed mice exhibited increases in body weight, liver weight, epididymal fat weight, and accumulation of fat in hepatocytes, and these effects were significantly attenuated by EAF supplementation. CONCLUSIONS: Allium fistulosum attenuates the development of NAFLD, and EAF elicits anti-lipogenic activity in liver. Therefore, EAF represents a promising candidate for use in the development of novel therapeutic drugs or drug combinations for the prevention and treatment of NAFLD.