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Hehl L, Creasy KT, Vitali C, Scorletti E, Seeling KS, Vell MS, Rendel MD, Conlon D, Vujkovic M, Zandvakili I, Trautwein C, Schneider KM, Rader DJ, Schneider CV. A genome-first approach to variants in MLXIPL and their association with hepatic steatosis and plasma lipids. Hepatol Commun 2024; 8:e0427. [PMID: 38668731 DOI: 10.1097/hc9.0000000000000427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 02/01/2024] [Indexed: 05/01/2024] Open
Abstract
BACKGROUND Common variants of the max-like protein X (MLX)-interacting protein-like (MLXIPL) gene, encoding the transcription factor carbohydrate-responsive element-binding protein, have been shown to be associated with plasma triglyceride levels. However, the role of these variants in steatotic liver disease (SLD) is unclear. METHODS We used a genome-first approach to analyze a variety of metabolic phenotypes and clinical outcomes associated with a common missense variant in MLXIPL, Gln241His, in 2 large biobanks: the UK Biobank and the Penn Medicine Biobank. RESULTS Carriers of MLXIPL Gln241His were associated with significantly lower serum levels of triglycerides, apolipoprotein-B, gamma-glutamyl transferase, and alkaline phosphatase. Additionally, MLXIPL Gln241His carriers were associated with significantly higher serum levels of HDL cholesterol and alanine aminotransferase. Carriers homozygous for MLXIPL Gln241His showed a higher risk of SLD in 2 unrelated cohorts. Carriers of MLXIPL Gln241His were especially more likely to be diagnosed with SLD if they were female, obese, and/or also carried the PNPLA3 I148M variant. Furthermore, the heterozygous carriage of MLXIPL Gln241His was associated with significantly higher all-cause, liver-related, and cardiovascular mortality rates. Nuclear magnetic resonance metabolomics data indicated that carriage of MLXIPL Gln241His was significantly associated with lower serum levels of VLDL and increased serum levels of HDL cholesterol. CONCLUSIONS Analyses of the MLXIPL Gln241His polymorphism showed a significant association with a higher risk of SLD diagnosis and elevated serum alanine aminotransferase as well as significantly lower serum triglycerides and apolipoprotein-B levels. MLXIPL might, therefore, be a potential pharmacological target for the treatment of SLD and hyperlipidemia, notably for patients at risk. More mechanistic studies are needed to better understand the role of MLXIPL Gln241His on lipid metabolism and steatosis development.
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Affiliation(s)
- Leonida Hehl
- Department of Medicine III, Gastroenterology, Metabolic diseases and Intensive Care, University Hospital RWTH Aachen, Aachen, Germany
| | - Kate T Creasy
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Cecilia Vitali
- Department of Medicine, Division of Translational Medicine and Human Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Eleonora Scorletti
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- The Institute for Translational Medicine and Therapeutics, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Katharina S Seeling
- Department of Medicine III, Gastroenterology, Metabolic diseases and Intensive Care, University Hospital RWTH Aachen, Aachen, Germany
| | - Mara S Vell
- Department of Medicine III, Gastroenterology, Metabolic diseases and Intensive Care, University Hospital RWTH Aachen, Aachen, Germany
| | - Miriam D Rendel
- Department of Medicine III, Gastroenterology, Metabolic diseases and Intensive Care, University Hospital RWTH Aachen, Aachen, Germany
| | - Donna Conlon
- Department of Medicine, Division of Translational Medicine and Human Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Marijana Vujkovic
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Inuk Zandvakili
- Department of Medicine, Division of Gastroenterology and Hepatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Internal Medicine, Division of Digestive Diseases, College of Medicine, University of Cincinnati, Cincinnati, OH, USA
| | - Christian Trautwein
- Department of Medicine III, Gastroenterology, Metabolic diseases and Intensive Care, University Hospital RWTH Aachen, Aachen, Germany
| | - Kai M Schneider
- Department of Medicine III, Gastroenterology, Metabolic diseases and Intensive Care, University Hospital RWTH Aachen, Aachen, Germany
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Daniel J Rader
- Department of Medicine, Division of Translational Medicine and Human Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Carolin V Schneider
- Department of Medicine III, Gastroenterology, Metabolic diseases and Intensive Care, University Hospital RWTH Aachen, Aachen, Germany
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- The Institute for Translational Medicine and Therapeutics, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Wang J, Wen Y, Zhao W, Zhang Y, Lin F, Ouyang C, Wang H, Yao L, Ma H, Zhuo Y, Huang H, Shi X, Feng L, Lin D, Jiang B, Li Q. Hepatic conversion of acetyl-CoA to acetate plays crucial roles in energy stress. eLife 2023; 12:RP87419. [PMID: 37902629 PMCID: PMC10615369 DOI: 10.7554/elife.87419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2023] Open
Abstract
Accumulating evidence indicates that acetate is increased under energy stress conditions such as those that occur in diabetes mellitus and prolonged starvation. However, how and where acetate is produced and the nature of its biological significance are largely unknown. We observed overproduction of acetate to concentrations comparable to those of ketone bodies in patients and mice with diabetes or starvation. Mechanistically, ACOT12 and ACOT8 are dramatically upregulated in the liver to convert free fatty acid-derived acetyl-CoA to acetate and CoA. This conversion not only provides a large amount of acetate, which preferentially fuels the brain rather than muscle, but also recycles CoA, which is required for sustained fatty acid oxidation and ketogenesis. We suggest that acetate is an emerging novel 'ketone body' that may be used as a parameter to evaluate the progression of energy stress.
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Affiliation(s)
- Jinyang Wang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, China
| | - Yaxin Wen
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, China
| | - Wentao Zhao
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, China
| | - Yan Zhang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, China
| | - Furong Lin
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, China
| | - Cong Ouyang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, China
| | - Huihui Wang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, China
| | - Lizheng Yao
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, China
| | - Huanhuan Ma
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, China
| | - Yue Zhuo
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, China
| | - Huiying Huang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, China
| | - Xiulin Shi
- Department of Endocrinology and Diabetes, Xiamen Diabetes Institute, Fujian Province Key Laboratory of Translational Research for Diabetes, The First Affiliated Hospital of Xiamen University, Xiamen, China
| | - Liubin Feng
- High-Field NMR Center, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
| | - Donghai Lin
- Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
| | - Bin Jiang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, China
| | - Qinxi Li
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, China
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Bhardwaj S, Thakur K, Sharma AK, Sharma D, Brar B, Mahajan D, Kumar S, Kumar R. Regulation of omega-3 fatty acids production by different genes in freshwater fish species: a review. FISH PHYSIOLOGY AND BIOCHEMISTRY 2023; 49:1005-1016. [PMID: 37684550 DOI: 10.1007/s10695-023-01236-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 08/27/2023] [Indexed: 09/10/2023]
Abstract
The present study aims to compare the gene expression of three different fish species (common carp, tilapia, and trout) with varying levels of fatty acids (FA). Based on transcriptome analysis and RNA sequencing, various genes and their associated metabolic pathways are identified. Pathways are categorized based on the genes they encode. Genes that were differentially expressed and their promoter's methylation patterns were revealed by RNA-seq analysis in common carp. Furthermore, fatty acid-enriched pathways, such as ARA4 and adipocytokine signaling, were also identified. Many genes and pathways may influence tilapia's growth and omega-3 content. Using the mTOR pathway, trout with differential expression were discovered to be involved in producing omega-3 fatty acids. This study revealed major pathways in fish species to produce omega-3 fatty acids.
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Affiliation(s)
- Shivani Bhardwaj
- Department of Animal Sciences, School of Life Sciences, Central University of Himachal Pradesh, District Kangra, Himachal Pradesh, 176206, India
| | - Kushal Thakur
- Department of Animal Sciences, School of Life Sciences, Central University of Himachal Pradesh, District Kangra, Himachal Pradesh, 176206, India
| | - Amit Kumar Sharma
- Department of Animal Sciences, School of Life Sciences, Central University of Himachal Pradesh, District Kangra, Himachal Pradesh, 176206, India
| | - Dixit Sharma
- Department of Animal Sciences, School of Life Sciences, Central University of Himachal Pradesh, District Kangra, Himachal Pradesh, 176206, India
| | - Bhavna Brar
- Department of Animal Sciences, School of Life Sciences, Central University of Himachal Pradesh, District Kangra, Himachal Pradesh, 176206, India
| | - Danish Mahajan
- Department of Animal Sciences, School of Life Sciences, Central University of Himachal Pradesh, District Kangra, Himachal Pradesh, 176206, India
| | - Sunil Kumar
- Department of Animal Sciences, School of Life Sciences, Central University of Himachal Pradesh, District Kangra, Himachal Pradesh, 176206, India
| | - Rakesh Kumar
- Department of Animal Sciences, School of Life Sciences, Central University of Himachal Pradesh, District Kangra, Himachal Pradesh, 176206, India.
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Sun B, Chen H, Xue J, Li P, Fu X. The role of GLUT2 in glucose metabolism in multiple organs and tissues. Mol Biol Rep 2023; 50:6963-6974. [PMID: 37358764 PMCID: PMC10374759 DOI: 10.1007/s11033-023-08535-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 05/17/2023] [Indexed: 06/27/2023]
Abstract
The glucose transporter family has an important role in the initial stage of glucose metabolism; Glucose transporters 2 (GLUTs, encoded by the solute carrier family 2, SLC2A genes) is the major glucose transporter in β-cells of pancreatic islets and hepatocytes but is also expressed in the small intestine, kidneys, and central nervous system; GLUT2 has a relatively low affinity to glucose. Under physiological conditions, GLUT2 transports glucose into cells and allows the glucose concentration to reach balance on the bilateral sides of the cellular membrane; Variation of GLUT2 is associated with various endocrine and metabolic disorders; In this study, we discussed the role of GLUT2 in participating in glucose metabolism and regulation in multiple organs and tissues and its effects on maintaining glucose homeostasis.
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Affiliation(s)
- Bo Sun
- Endorcrine and Metabolism Department, Lanzhou University Second Hospital, Lanzhou, 730000, China
- Department of Infantile Endocrine Genetic Metabolism, Gansu Maternal and child Health Care Hospital, Lanzhou, 730000, China
| | - Hui Chen
- Endorcrine and Metabolism Department, Lanzhou University Second Hospital, Lanzhou, 730000, China.
| | - Jisu Xue
- EndEnorcrine and Metabolism Department, Shenzhen Bao 'an People's Hospital (Group), Shenzhen, 518100, China
| | - Peiwu Li
- Key Laboratory of Emergency Medicine, Lanzhou University Second Hospital, Lanzhou, 730000, China
| | - Xu Fu
- Key Laboratory of Emergency Medicine, Lanzhou University Second Hospital, Lanzhou, 730000, China
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Moon YA. Emerging roles of polyunsaturated fatty acid synthesis pathway in colorectal cancer. Anim Cells Syst (Seoul) 2023; 27:61-71. [PMID: 36970499 PMCID: PMC10035963 DOI: 10.1080/19768354.2023.2189933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023] Open
Abstract
The development of colorectal cancer typically involves the accumulated influences of genetic alterations, medical issues, lifestyle, and diet. Dietary fatty acids appear to affect the tumorigenesis and progression of colorectal cancer. Despite conflicting results, the current consensus on the effects of very long-chain polyunsaturated fatty acids on colorectal cancer is that low levels of eicosapentaenoic acid and docosahexaenoic acid, and high levels of arachidonic acid are associated with an increased risk of colorectal cancer. Altered levels of arachidonic acid in membrane phospholipids can change the levels of prostaglandin E2, which affect the biological activities of cancer cells in multiple stages. Arachidonic acid and other very long-chain polyunsaturated fatty acids can affect tumorigenesis in prostaglandin E2-independent manners as well, including stabilization of β-catenine, ferroptosis, ROS generation, regulation of transcription factors, and de novo lipogenesis. Recent studies have revealed an association between the activities of enzymes synthesizing very long-chain polyunsaturated fatty acids and tumorigenesis and cancer progression, although the mechanisms are still unknown. In this study, PUFA effects on tumorigenesis, the endogenous very long-chain polyunsaturated fatty acid synthesis pathway, metabolites of arachidonic acid and their effects on tumorigenesis and progression of CRC, and current knowledge that supports the association of the enzymes involved in the polyunsaturated fatty acid synthesis pathway with colorectal cancer tumorigenesis and progression are reviewed.
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Affiliation(s)
- Young-Ah Moon
- Department of Molecular Medicine, Inha University College of Medicine, Incheon, South Korea
- Young-Ah Moon Department of Molecular Medicine, Inha University College of Medicine, Incheon, South Korea
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Maldonado-González M, Hernández-Nazara ZH, Torres-Castillo N, Martínez-López E, de la Cruz-Color L, Ruíz-Madrigal B. Association between the rs3812316 Single Nucleotide Variant of the MLXIPL Gene and Alpha-Linolenic Acid Intake with Triglycerides in Mexican Mestizo Women. Nutrients 2022; 14:nu14224726. [PMID: 36432414 PMCID: PMC9692638 DOI: 10.3390/nu14224726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 11/01/2022] [Accepted: 11/05/2022] [Indexed: 11/11/2022] Open
Abstract
The carbohydrate response element binding protein (ChREBP) is a key transcription factor to understand the gene−diet−nutrient relationship that leads to metabolic diseases. We aimed to analyze the association between the rs17145750 and rs3812316 SNVs (single nucleotide variants) of the MLXIPL gene with dietary, anthropometric, and biochemical variables in Mexican Mestizo subjects. This is a cross-sectional study of 587 individuals. Genotyping was performed by allelic discrimination. In addition, liver and adipose tissue biopsies were obtained from a subgroup of 24 subjects to analyze the expression of the MLXIPL gene. An in silico test of the protein stability and allelic imbalance showed that rs17145750 and rs3812316 showed a high rate of joint heritability in a highly conserved area. The G allele of rs3812316 was associated with lower triglyceride levels (OR = −0.070 ± 0.027, p < 0.011, 95% CI = −0.124 to −0.016), the production of an unstable protein (ΔΔG −0.83 kcal/mol), and probably lower tissue mRNA levels. In addition, we found independent factors that also influence triglyceride levels, such as insulin resistance, HDL-c, and dietary protein intake in women. Our data showed that the association of rs3812316 on triglycerides was only observed in patients with an inadequate alpha-linolenic acid intake (1.97 ± 0.03 vs. 2.11 ± 0.01 log mg/dL, p < 0.001).
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Affiliation(s)
- Montserrat Maldonado-González
- Laboratorio de Investigación en Microbiología, Departamento de Microbiología y Patología, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara 44340, Jalisco, Mexico
| | - Zamira H. Hernández-Nazara
- Instituto de Investigación en Enfermedades Crónicas Degenerativas, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara 44340, Jalisco, Mexico
| | - Nathaly Torres-Castillo
- Instituto de Nutrigenética y Nutrigenómica Traslacional, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara 44100, Jalisco, Mexico
| | - Erika Martínez-López
- Instituto de Nutrigenética y Nutrigenómica Traslacional, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara 44100, Jalisco, Mexico
| | - Lucia de la Cruz-Color
- Centro de Investigación en Biotecnología Microbiana y Alimentaria, División de Desarrollo Biotecnológico, Centro Universitario de la Ciénega, Universidad de Guadalajara, Guadalajara 47820, Jalisco, Mexico
| | - Bertha Ruíz-Madrigal
- Laboratorio de Investigación en Microbiología, Departamento de Microbiología y Patología, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara 44340, Jalisco, Mexico
- Correspondence: ; Tel.: +52-(33)10585200
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Critical Role of Aquaporins in Cancer: Focus on Hematological Malignancies. Cancers (Basel) 2022; 14:cancers14174182. [PMID: 36077720 PMCID: PMC9455074 DOI: 10.3390/cancers14174182] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 08/23/2022] [Accepted: 08/26/2022] [Indexed: 12/04/2022] Open
Abstract
Simple Summary Aquaporins are proteins able to regulate the transfer of water and other small substances such as ions, glycerol, urea, and hydrogen peroxide across cellular membranes. AQPs provide for a huge variety of physiological phenomena; their alteration provokes several types of pathologies including cancer and hematological malignancies. Our review presents data revealing the possibility of employing aquaporins as biomarkers in patients with hematological malignancies and evaluates the possibility that interfering with the expression of aquaporins could represent an effective treatment for hematological malignancies. Abstract Aquaporins are transmembrane molecules regulating the transfer of water and other compounds such as ions, glycerol, urea, and hydrogen peroxide. Their alteration has been reported in several conditions such as cancer. Tumor progression might be enhanced by aquaporins in modifying tumor angiogenesis, cell volume adaptation, proteases activity, cell–matrix adhesions, actin cytoskeleton, epithelial–mesenchymal transitions, and acting on several signaling pathways facilitating cancer progression. Close connections have also been identified between the aquaporins and hematological malignancies. However, it is difficult to identify a unique action exerted by aquaporins in different hemopathies, and each aquaporin has specific effects that vary according to the class of aquaporin examined and to the different neoplastic cells. However, the expression of aquaporins is altered in cell cultures and in patients with acute and chronic myeloid leukemia, in lymphoproliferative diseases and in multiple myeloma, and the different expression of aquaporins seems to be able to influence the efficacy of treatment and could have a prognostic significance, as greater expression of aquaporins is correlated to improved overall survival in leukemia patients. Finally, we assessed the possibility that modifying the aquaporin expression using aquaporin-targeting regulators, specific monoclonal antibodies, and even aquaporin gene transfer could represent an effective therapy of hematological malignancies.
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Luo MJ, Wang Y, Chen SY, Yang ZM. Astragalus Polysaccharides Alleviate Type 2 Diabetic Rats by Reversing the Expressions of Sweet Taste Receptors and Genes Related to Glycolipid Metabolism in Liver. Front Pharmacol 2022; 13:916603. [PMID: 36059978 PMCID: PMC9428788 DOI: 10.3389/fphar.2022.916603] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Accepted: 06/20/2022] [Indexed: 11/13/2022] Open
Abstract
Sweet taste receptors (STRs) play an important role in glucose metabolism, and type 2 diabetic rats have abnormal expressions of STRs in multiple tissues. Astragalus polysaccharides (APS) has shown a significant therapeutic effect on type 2 diabetes mellitus (T2DM), but its mechanism needs to be further clarified. T2DM rat model was induced by intraperitoneal streptozotocin injection and treated with APS for 8 weeks. Daily indicators of experimental rats were observed, and expression levels of STRs and genes related to glycolipid metabolism were determined by real-time quantitative PCR and western blot. The present study revealed that APS alleviated the symptoms of T2DM rats, improved HOMA-IR and promoted insulin secretion. Gene expression analysis found that APS significantly increased the expressions of signaling molecules in STRs pathways, including taste receptor family 1 member 2 (T1R2), α-gustducin (Gα) and transient receptor potential cation channel subfamily member 5 (TRPM5), and reversed the expressions of genes related to glucolipid metabolism, including glucose transporters 2 and 4 (GLUT2 and GLUT4), pyruvate carboxylase (PC), fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC) in the liver of T2DM rats. However, APS had no influences on the expressions of genes, including glycogen synthase kinase-3 beta (GSK-3β), pyruvate kinase (PK) and phosphoenolpyruvate carboxykinase (PEPCK) in the liver of T2DM rats. These results suggested that the physiological roles of STRs in the liver were involved with glucose transport and metabolism. APS alleviated T2DM rats by activating the STRs pathway, and promoted glucose transport and lipogenesis.
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Parlati L, Régnier M, Guillou H, Postic C. New targets for NAFLD. JHEP Rep 2021; 3:100346. [PMID: 34667947 PMCID: PMC8507191 DOI: 10.1016/j.jhepr.2021.100346] [Citation(s) in RCA: 75] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 07/15/2021] [Accepted: 07/17/2021] [Indexed: 02/08/2023] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is a growing cause of chronic liver disease worldwide. It is characterised by steatosis, liver inflammation, hepatocellular injury and progressive fibrosis. Several preclinical models (dietary and genetic animal models) of NAFLD have deepened our understanding of its aetiology and pathophysiology. Despite the progress made, there are currently no effective treatments for NAFLD. In this review, we will provide an update on the known molecular pathways involved in the pathophysiology of NAFLD and on ongoing studies of new therapeutic targets.
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Key Words
- ACC, acetyl-CoA carboxylase
- ASK1, apoptosis signal-regulating kinase 1
- CAP, controlled attenuation parameter
- ChREBP
- ChREBP, carbohydrate responsive element–binding protein
- FAS, fatty acid synthase
- FFA, free fatty acid
- FGF21, fibroblast growth factor-21
- FXR
- FXR, farnesoid X receptor
- GGT, gamma glutamyltransferase
- HCC, hepatocellular carcinoma
- HFD, high-fat diet
- HSC, hepatic stellate cells
- HSL, hormone-sensitive lipase
- HVPG, hepatic venous pressure gradient
- IL-, interleukin-
- JNK, c-Jun N-terminal kinase
- LXR
- LXR, liver X receptor
- MCD, methionine- and choline-deficient
- MUFA, monounsaturated fatty acids
- NAFLD
- NAFLD, non-alcoholic fatty liver disease
- NASH
- NASH, non-alcoholic steatohepatitis
- NEFA
- NEFA, non-esterified fatty acid
- PPARα
- PPARα, peroxisome proliferator-activated receptor-α
- PUFAs, polyunsaturated fatty acids
- PY, persons/years
- Phf2, histone demethylase plant homeodomain finger 2
- RCT, randomised controlled trial
- SCD1, stearoyl-CoA desaturase-1
- SFA, saturated fatty acid
- SREBP-1c
- SREBP-1c, sterol regulatory element–binding protein-1c
- TCA, tricarboxylic acid
- TLR4, Toll-like receptor 4
- TNF-α, tumour necrosis factor-α
- VLDL, very low-density lipoprotein
- animal models
- glucotoxicity
- lipotoxicity
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Affiliation(s)
- Lucia Parlati
- Université de Paris, Institut Cochin, CNRS, INSERM, F- 75014 Paris, France.,Hôpital Cochin, 24, rue du Faubourg Saint Jacques, 75014 Paris, France
| | - Marion Régnier
- UCLouvain, Université catholique de Louvain, Walloon Excellence in Life Sciences and BIOtechnology, Louvain Drug Research Institute, Metabolism and Nutrition Research Group, Brussels, Belgium
| | - Hervé Guillou
- Toxalim, Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, Toulouse 31027, France
| | - Catherine Postic
- Université de Paris, Institut Cochin, CNRS, INSERM, F- 75014 Paris, France
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Lv G, Zeng Q, Ding X, Bai S, Zhang K. Effects of age and diet forms on growth-development patterns, serum metabolism indicators, and parameters of body fat deposition in Cherry Valley ducks. Anim Biosci 2021; 35:247-259. [PMID: 34289584 PMCID: PMC8738944 DOI: 10.5713/ab.21.0096] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 05/28/2021] [Indexed: 12/28/2022] Open
Abstract
Objective This study was conducted to investigate the effects of age and diet forms on growth-development patterns, serum metabolism indicators, and parameters of body fat deposition in Cherry Valley ducks. Methods According to the hatching age and initial weight, a total of 150 1-day-old male SM3 Cherry Valley ducks were randomly assigned to two diet forms (pellet vs powder form). Each treatment had with 5 replicates per treatment and 15 meat ducks per replicate. The study lasted 42 d, which was divided into two periods (1 to 21 vs 22 to 42 d). Results Our results showed that compared with powder group, ducks in pellet group had greater growth performance during different period (p<0.05). The inflection point was 24 d and was not numerically affected by diet forms. Increasing age (42 vs 21 d) significantly increased the weight of body fat and hepatic fat metabolism related enzyme activities in ducks (p<0.05), meanwhile, increasing age (42 vs 21 d) improved serum metabolism indicators and decreased mRNA expression levels of fat metabolism-related genes in liver (p<0.05). Ducks fed different diets (pellet vs powder form) increased growth performance as well as the weight of body fat and improved serum metabolism indicators (p<0.05). In addition, interactions were found between age and diet forms on the levels of serum metabolism indicators in ducks (p<0.05). Conclusion In conclusion, powder feed reduced growth performance of ducks, and the day of inflection point was 24 days old. Ducks with higher age or fed with pellet diet showed higher fat deposition. The effect of age and feed forms on body fat deposition might result from changes in the contents of serum metabolism indicators, key enzyme activity of lipid production, and hepatic gene expressions.
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Affiliation(s)
- Gang Lv
- Institute of Livestock and Poultry, Tongwei Co., Ltd., Chengdu, Sichuan-610041, China
| | - Qiufeng Zeng
- Institute of Animal Nutrition, Sichuan Agricultural University, Chengdu, Sichuan-611130, China
| | - Xuemei Ding
- Institute of Animal Nutrition, Sichuan Agricultural University, Chengdu, Sichuan-611130, China
| | - Shiping Bai
- Institute of Animal Nutrition, Sichuan Agricultural University, Chengdu, Sichuan-611130, China
| | - Keying Zhang
- Institute of Animal Nutrition, Sichuan Agricultural University, Chengdu, Sichuan-611130, China
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Drag J, Knapik-Czajka M, Gawedzka A, Gdula-Argasinska J, Jaskiewicz J. Impact of High-Sucrose Diet on the mRNA Levels for Elongases and Desaturases and Estimated Protein Activity in Rat Adipose Tissue. BIOCHEMISTRY. BIOKHIMIIA 2021; 86:525-532. [PMID: 33993857 DOI: 10.1134/s0006297921050011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 02/09/2021] [Accepted: 02/09/2021] [Indexed: 06/12/2023]
Abstract
Fatty acids (FAs) present in the adipose tissue (AT) can be modified by elongases and desaturases. These enzymes are regulated by different factors including nutrients. The aim of the study was to evaluate the impact of high-sucrose diet (HSD; 68% sucrose) on the levels of mRNAs for elongases (Elovl2, Elovl5, Elovl6) and desaturases (Fads1, Fads2, Scd) and on the activity of the corresponding proteins in the rat AT. Male Wistar rats were randomized into two study groups: fed with an HSD and with a standard diet (ST). The mRNA levels were determined by a semi-quantitative reverse transcription-PCR. FA composition was analyzed by gas chromatography, and FA ratios were used to estimate the activity of the enzymes. In the HSD rats, the levels of Elovl5, Elovl6, Fads1, and Scd mRNAs were higher, while the level of Fads2 mRNA was lower than in the ST group. Higher levels of Elovl5 and Elovl6 mRNAs corresponded to higher relative activities of these enzymes, while downregulation of the Fads2 mRNA was associated with the lower activity of this desaturase. In contrast, an increase in the level of Scd mRNA was accompanied by a decrease in the enzyme activity. Less monounsaturated FAs were detected in the AT of HSD rats than in the ST group. The composition of individual FAs differed between the groups. This study supports the notion that the regulation of mRNA levels and activity of both elongases and desaturases play an important role in managing the AT lipid composition in response to changes in the dietary status.
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Affiliation(s)
- Jagoda Drag
- Department of Biochemical Analytics, Faculty of Pharmacy, Jagiellonian University Medical College, Krakow, 30-688, Poland.
| | - Malgorzata Knapik-Czajka
- Department of Biochemical Analytics, Faculty of Pharmacy, Jagiellonian University Medical College, Krakow, 30-688, Poland.
| | - Anna Gawedzka
- Department of Biochemical Analytics, Faculty of Pharmacy, Jagiellonian University Medical College, Krakow, 30-688, Poland.
| | - Joanna Gdula-Argasinska
- Department of Radioligands, Faculty of Pharmacy, Jagiellonian University Medical College, Krakow, 30-688, Poland.
| | - Jerzy Jaskiewicz
- Department of Biochemical Analytics, Faculty of Pharmacy, Jagiellonian University Medical College, Krakow, 30-688, Poland.
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12
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Canosa LF, Bertucci JI. Nutrient regulation of somatic growth in teleost fish. The interaction between somatic growth, feeding and metabolism. Mol Cell Endocrinol 2020; 518:111029. [PMID: 32941926 DOI: 10.1016/j.mce.2020.111029] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 07/03/2020] [Accepted: 09/07/2020] [Indexed: 12/13/2022]
Abstract
This review covers the current knowledge on the regulation of the somatic growth axis and its interaction with metabolism and feeding regulation. The main endocrine and neuroendocrine factors regulating both the growth axis and feeding behavior will be briefly summarized. Recently discovered neuropeptides and peptide hormones will be mentioned in relation to feeding control as well as growth hormone regulation. In addition, the influence of nutrient and nutrient sensing mechanisms on growth axis will be highlighted. We expect that in this process gaps of knowledge will be exposed, stimulating future research in those areas.
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Affiliation(s)
- Luis Fabián Canosa
- Instituto Tecnológico de Chascomús (INTECH), CONICET-UNSAM, Chascomús, Buenos Aires, Argentina.
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13
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Glucose transporters in adipose tissue, liver, and skeletal muscle in metabolic health and disease. Pflugers Arch 2020; 472:1273-1298. [PMID: 32591906 PMCID: PMC7462924 DOI: 10.1007/s00424-020-02417-x] [Citation(s) in RCA: 193] [Impact Index Per Article: 48.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 06/01/2020] [Accepted: 06/05/2020] [Indexed: 12/13/2022]
Abstract
A family of facilitative glucose transporters (GLUTs) is involved in regulating tissue-specific glucose uptake and metabolism in the liver, skeletal muscle, and adipose tissue to ensure homeostatic control of blood glucose levels. Reduced glucose transport activity results in aberrant use of energy substrates and is associated with insulin resistance and type 2 diabetes. It is well established that GLUT2, the main regulator of hepatic hexose flux, and GLUT4, the workhorse in insulin- and contraction-stimulated glucose uptake in skeletal muscle, are critical contributors in the control of whole-body glycemia. However, the molecular mechanism how insulin controls glucose transport across membranes and its relation to impaired glycemic control in type 2 diabetes remains not sufficiently understood. An array of circulating metabolites and hormone-like molecules and potential supplementary glucose transporters play roles in fine-tuning glucose flux between the different organs in response to an altered energy demand.
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14
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Yu J, Peng J, Luan Z, Zheng F, Su W. MicroRNAs as a Novel Tool in the Diagnosis of Liver Lipid Dysregulation and Fatty Liver Disease. Molecules 2019; 24:molecules24020230. [PMID: 30634538 PMCID: PMC6358728 DOI: 10.3390/molecules24020230] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Revised: 12/23/2018] [Accepted: 12/24/2018] [Indexed: 02/07/2023] Open
Abstract
In recent years, metabolic disorder, especially fatty liver disease, has been considered a major challenge to global health. The attention of researchers focused on expanding knowledge of the regulation mechanism behind these diseases and towards the new diagnostics tools and treatments. The pathophysiology of the fatty liver disease is undoubtedly complex. Abnormal hepatic lipid accumulation is a major symptom of most metabolic diseases. Therefore, the identification of novel regulation factors of lipid metabolism is important and meaningful. As a new diagnostic tool, the function of microRNAs during fatty liver disease has recently come into notice in biological research. Accumulating evidence supports the influence of miRNAs in lipid metabolism. In this review, we discuss the potential role of miRNAs in liver lipid metabolism and the pathogenesis of fatty liver disease.
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Affiliation(s)
- Jingwei Yu
- Shenzhen University Medical Center, Shenzhen University Health Science Center, Shenzhen 518060, China.
- Department of Biology, Guangdong Pharmaceutical University, Guangzhou 510006, China.
| | - Jun Peng
- Shenzhen University Medical Center, Shenzhen University Health Science Center, Shenzhen 518060, China.
| | - Zhilin Luan
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, Liaoning 116044, China.
| | - Feng Zheng
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, Liaoning 116044, China.
| | - Wen Su
- Shenzhen University Medical Center, Shenzhen University Health Science Center, Shenzhen 518060, China.
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15
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Sex Differences in Hepatic De Novo Lipogenesis with Acute Fructose Feeding. Nutrients 2018; 10:nu10091263. [PMID: 30205493 PMCID: PMC6164310 DOI: 10.3390/nu10091263] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 09/05/2018] [Accepted: 09/06/2018] [Indexed: 12/21/2022] Open
Abstract
Dietary free sugars have received much attention over the past few years. Much of the focus has been on the effect of fructose on hepatic de novo lipogenesis (DNL). Therefore the aim of the present study was to investigate the effects of meals high and low in fructose on postprandial hepatic DNL and fatty acid partitioning and dietary fatty acid oxidation. Sixteen healthy adults (eight men, eight women) participated in this randomised cross-over study; study days were separated by a 4-week wash-out period. Hepatic DNL and dietary fatty acid oxidation were assessed using stable-isotope tracer methodology. Consumption of the high fructose meal significantly increased postprandial hepatic DNL to a greater extent than consumption of the low fructose meal and this effect was evident in women but not men. Despite an increase in hepatic DNL, there was no change in dietary fatty acid oxidation. Taken together, our data show that women are more responsive to ingestion of higher amounts of fructose than men and if continued over time this may lead to changes in hepatic fatty acid partitioning and eventually liver fat content.
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16
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The histone demethylase Phf2 acts as a molecular checkpoint to prevent NAFLD progression during obesity. Nat Commun 2018; 9:2092. [PMID: 29844386 PMCID: PMC5974278 DOI: 10.1038/s41467-018-04361-y] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 04/23/2018] [Indexed: 01/01/2023] Open
Abstract
Aberrant histone methylation profile is reported to correlate with the development and progression of NAFLD during obesity. However, the identification of specific epigenetic modifiers involved in this process remains poorly understood. Here, we identify the histone demethylase Plant Homeodomain Finger 2 (Phf2) as a new transcriptional co-activator of the transcription factor Carbohydrate Responsive Element Binding Protein (ChREBP). By specifically erasing H3K9me2 methyl-marks on the promoter of ChREBP-regulated genes, Phf2 facilitates incorporation of metabolic precursors into mono-unsaturated fatty acids, leading to hepatosteatosis development in the absence of inflammation and insulin resistance. Moreover, the Phf2-mediated activation of the transcription factor NF-E2-related factor 2 (Nrf2) further reroutes glucose fluxes toward the pentose phosphate pathway and glutathione biosynthesis, protecting the liver from oxidative stress and fibrogenesis in response to diet-induced obesity. Overall, our findings establish a downstream epigenetic checkpoint, whereby Phf2, through facilitating H3K9me2 demethylation at specific gene promoters, protects liver from the pathogenesis progression of NAFLD.
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17
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Bai M, Liu Y, Zhou F, Zhang Y, Zhu Q, Zhang L, Zhang Q, Wang S, Zhu K, Wang X, Zhou L. Berberine inhibits glucose oxidation and insulin secretion in rat islets. Endocr J 2018; 65:469-477. [PMID: 29467344 DOI: 10.1507/endocrj.ej17-0543] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Glucose promotes insulin secretion primarily via its metabolism and the production of metabolic coupling factors in beta-cells. The activation of AMP-activated protein kinase (AMPK), an energy sensor, results in a decrease in insulin secretion from beta-cells, but its mechanism remains largely unknown. Berberine, an oral anti-diabetic drug, has been shown to activate AMPK in multiple peripheral tissues. Here, we examined the effects of berberine and AMPK activation on insulin secretion and glucose oxidation in rat islets. Our results showed that berberine inhibited glucose-stimulated insulin secretion from rat islets with AMPK activation. When glucose concentration was elevated to 25 mmol/L, the inhibitory action of berberine on insulin secretion disappeared. Furthermore, berberine significantly decreased oxygen consumption rate (OCR) and ATP production induced by high glucose in rat islets. Although adenovirus-mediated overexpression of constituent-activated AMPK markedly decreased GSIS and OCR in rat islets, the inhibition of AMPK by compound C did not reverse berberine-suppressed OCR. In addition, berberine attenuated glucose-stimulated expression of fatty acid synthase. These results indicate that berberine-mediated deceleration of glucose oxidation is tightly link to the decreased insulin secretion in islets independent of AMPK activation and inhibition of fatty acid synthesis may also contribute to the effect of berberine on insulin secretion.
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Affiliation(s)
- Mengyao Bai
- Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Department of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China
| | - Yun Liu
- Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Department of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China
| | - Feiye Zhou
- Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Department of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China
| | - Yuqing Zhang
- Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Department of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China
| | - Qin Zhu
- Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Department of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China
| | - Linlin Zhang
- Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Department of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China
| | - Qi Zhang
- Department of Endocrinology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China
| | - Shushu Wang
- Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Department of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China
| | - Kecheng Zhu
- Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Department of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China
| | - Xiao Wang
- Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Department of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China
| | - Libin Zhou
- Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Department of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China
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18
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Pérez-Ramírez IF, Becerril-Ocampo LJ, Reynoso-Camacho R, Herrera MD, Guzmán-Maldonado SH, Cruz-Bravo RK. Cookies elaborated with oat and common bean flours improved serum markers in diabetic rats. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2018; 98:998-1007. [PMID: 28718519 DOI: 10.1002/jsfa.8548] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 07/11/2017] [Accepted: 07/11/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND Common beans have been associated with anti-diabetic effects, due to its high content of bioactive compounds. Nevertheless, its consumption has decreased worldwide. Therefore, there is an increasing interest in the development of novel functional foods elaborated with common beans. The aim of this study was to evaluate the anti-diabetic effect of oat-bean flour cookies, and to analyze its bioactive composition, using commercial oat-wheat cookies for comparative purposes. RESULTS Oat-bean cookies (1.2 g kg-1 ) slightly decreased serum glucose levels (∼1.1-fold) and increased insulin levels (∼1.2-fold) in diabetic rats, reducing the hyperglycemic peak in healthy rats (∼1.1-fold). Oat-bean cookies (0.8 and 1.2 g kg-1 ) exerted a greater hypolipidemic effect than commercial oat-wheat cookies (1.2 g kg-1 ), as observed in decreased serum triglycerides and low-density lipoprotein cholesterol. Furthermore, the supplementation with 1.2 g kg-1 oat-bean cookies decreased atherogenic index and serum C-reactive protein levels, suggesting their cardioprotective potential. The beneficial effect of oat-bean cookies was associated with their high content of dietary fiber and galacto oligosaccharides, as well as chlorogenic acid, rutin, protocatechuic acid, β-sitosterol and soyasaponins. CONCLUSION These results suggest that common beans can be used as functional ingredients for the elaboration of cookies with anti-diabetic effects. © 2017 Society of Chemical Industry.
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Affiliation(s)
| | | | | | - Mayra D Herrera
- Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias (INIFAP), Campus Zacatecas, Campo Experimental Zacatecas, Calera, México
| | - S Horacio Guzmán-Maldonado
- Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias (INIFAP), Campo Experimental Bajío, Celaya, México
| | - Raquel K Cruz-Bravo
- Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias (INIFAP), Campus Zacatecas, Campo Experimental Zacatecas, Calera, México
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19
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Senese R, Cioffi F, de Lange P, Leanza C, Iannucci LF, Silvestri E, Moreno M, Lombardi A, Goglia F, Lanni A. Both 3,5-Diiodo-L-Thyronine and 3,5,3'-Triiodo-L-Thyronine Prevent Short-term Hepatic Lipid Accumulation via Distinct Mechanisms in Rats Being Fed a High-Fat Diet. Front Physiol 2017; 8:706. [PMID: 28959215 PMCID: PMC5603695 DOI: 10.3389/fphys.2017.00706] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 08/31/2017] [Indexed: 12/14/2022] Open
Abstract
3,3′,5-triiodo-L-thyronine (T3) improves hepatic lipid accumulation by increasing lipid catabolism but it also increases lipogenesis, which at first glance appears contradictory. Recent studies have shown that 3,5-diiodothyronine (T2), a natural thyroid hormone derivative, also has the capacity to stimulate hepatic lipid catabolism, however, little is known about its possible effects on lipogenic gene expression. Because genes classically involved in hepatic lipogenesis such as SPOT14, acetyl-CoA-carboxylase (ACC), and fatty acid synthase (FAS) contain thyroid hormone response elements (TREs), we studied their transcriptional regulation, focusing on TRE-mediated effects of T3 compared to T2 in rats receiving high-fat diet (HFD) for 1 week. HFD rats showed a marked lipid accumulation in the liver, which was significantly reduced upon simultaneous administration of either T3 or T2 with the diet. When administered to HFD rats, T2, in contrast with T3, markedly downregulated the expression of the above-mentioned genes. T2 downregulated expression of the transcription factors carbohydrate-response element-binding protein (ChREBP) and sterol regulatory element binding protein-1c (SREBP-1c) involved in activation of transcription of these genes, which explains the suppressed expression of their target genes involved in lipogenesis. T3, however, did not repress expression of the TRE-containing ChREBP gene but repressed SREBP-1c expression. Despite suppression of SREBP-1c expression by T3 (which can be explained by the presence of nTRE in its promoter), the target genes were not suppressed, but normalized to HFD reference levels or even upregulated (ACC), partly due to the presence of TREs on the promoters of these genes and partly to the lack of suppression of ChREBP. Thus, T2 and T3 probably act by different molecular mechanisms to achieve inhibition of hepatic lipid accumulation.
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Affiliation(s)
- Rosalba Senese
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università degli Studi della Campania, "Luigi Vanvitelli" CasertaCaserta, Italy
| | - Federica Cioffi
- Dipartimento di Scienze e Tecnologie, Università degli Studi del SannioBenevento, Italy
| | - Pieter de Lange
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università degli Studi della Campania, "Luigi Vanvitelli" CasertaCaserta, Italy
| | - Cristina Leanza
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università degli Studi della Campania, "Luigi Vanvitelli" CasertaCaserta, Italy
| | - Liliana F Iannucci
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università degli Studi della Campania, "Luigi Vanvitelli" CasertaCaserta, Italy
| | - Elena Silvestri
- Dipartimento di Scienze e Tecnologie, Università degli Studi del SannioBenevento, Italy
| | - Maria Moreno
- Dipartimento di Scienze e Tecnologie, Università degli Studi del SannioBenevento, Italy
| | - Assunta Lombardi
- Dipartimento di Biologia, Università degli Studi di Napoli Federico IINaples, Italy
| | - Fernando Goglia
- Dipartimento di Scienze e Tecnologie, Università degli Studi del SannioBenevento, Italy
| | - Antonia Lanni
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università degli Studi della Campania, "Luigi Vanvitelli" CasertaCaserta, Italy
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20
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Pillon Barcelos R, Freire Royes LF, Gonzalez-Gallego J, Bresciani G. Oxidative stress and inflammation: liver responses and adaptations to acute and regular exercise. Free Radic Res 2017; 51:222-236. [PMID: 28166653 DOI: 10.1080/10715762.2017.1291942] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The liver is remarkably important during exercise outcomes due to its contribution to detoxification, synthesis, and release of biomolecules, and energy supply to the exercising muscles. Recently, liver has been also shown to play an important role in redox status and inflammatory modulation during exercise. However, while several studies have described the adaptations of skeletal muscles to acute and chronic exercise, hepatic changes are still scarcely investigated. Indeed, acute intense exercise challenges the liver with increased reactive oxygen species (ROS) and inflammation onset, whereas regular training induces hepatic antioxidant and anti-inflammatory improvements. Acute and regular exercise protocols in combination with antioxidant and anti-inflammatory supplementation have been also tested to verify hepatic adaptations to exercise. Although positive results have been reported in some acute models, several studies have shown an increased exercise-related stress upon liver. A similar trend has been observed during training: while synergistic effects of training and antioxidant/anti-inflammatory supplementations have been occasionally found, others reported a blunting of relevant adaptations to exercise, following the patterns described in skeletal muscles. This review discusses current data regarding liver responses and adaptation to acute and regular exercise protocols alone or combined with antioxidant and anti-inflammatory supplementation. The understanding of the mechanisms behind these modulations is of interest for both exercise-related health and performance outcomes.
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Affiliation(s)
- Rômulo Pillon Barcelos
- a Instituto de Ciências Biológicas , Universidade de Passo Fundo , Passo Fundo , Brazil.,b Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica (PPGBTOx) , Universidade Federal de Santa Maria (UFSM) , Santa Maria , Brazil
| | - Luiz Fernando Freire Royes
- b Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica (PPGBTOx) , Universidade Federal de Santa Maria (UFSM) , Santa Maria , Brazil.,c Laboratório de Bioquímica do Exercício, Centro de Educação Física e Desportos , Universidade Federal de Santa Maria (UFSM) , Santa Maria , Brazil
| | - Javier Gonzalez-Gallego
- d Institute of Biomedicine (IBIOMED) and Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) , University of León , León , Spain
| | - Guilherme Bresciani
- e Grupo de Investigación en Rendimiento Físico y Salud (IRyS), Escuela de Educación Física , Pontificia Universidad Católica de Valparaiso , Valparaiso , Chile
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21
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Tomita Y, Dorward H, Yool AJ, Smith E, Townsend AR, Price TJ, Hardingham JE. Role of Aquaporin 1 Signalling in Cancer Development and Progression. Int J Mol Sci 2017; 18:ijms18020299. [PMID: 28146084 PMCID: PMC5343835 DOI: 10.3390/ijms18020299] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 01/19/2017] [Accepted: 01/23/2017] [Indexed: 02/07/2023] Open
Abstract
Cancer is a major health burden worldwide. Despite the advances in our understanding of its pathogenesis and continued improvement in cancer management and outcomes, there remains a strong clinical demand for more accurate and reliable biomarkers of metastatic progression and novel therapeutic targets to abrogate angiogenesis and tumour progression. Aquaporin 1 (AQP1) is a small hydrophobic integral transmembrane protein with a predominant role in trans-cellular water transport. Recently, over-expression of AQP1 has been associated with many types of cancer as a distinctive clinical prognostic factor. This has prompted researchers to evaluate the link between AQP1 and cancer biological functions. Available literature implicates the role of AQP1 in tumour cell migration, invasion and angiogenesis. This article reviews the current understanding of AQP1-facilitated tumour development and progression with a focus on regulatory mechanisms and downstream signalling pathways.
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Affiliation(s)
- Yoko Tomita
- Molecular Oncology, Basil Hetzel Institute, The Queen Elizabeth Hospital & Discipline of Physiology, School of Medicine, University of Adelaide, Adelaide, SA 5000, Australia.
| | - Hilary Dorward
- Molecular Oncology, Basil Hetzel Institute, The Queen Elizabeth Hospital, Woodville South, SA 5011, Australia.
| | - Andrea J Yool
- Discipline of Physiology, School of Medicine, University of Adelaide, Adelaide, SA 5000, Australia.
| | - Eric Smith
- Molecular Oncology, Basil Hetzel Institute, The Queen Elizabeth Hospital, Woodville South, SA 5011, Australia.
| | - Amanda R Townsend
- Medical Oncology, The Queen Elizabeth Hospital & School of Medicine, University of Adelaide, Adelaide, SA 5000, Australia.
| | - Timothy J Price
- Medical Oncology, The Queen Elizabeth Hospital & School of Medicine, University of Adelaide, Adelaide, SA 5000, Australia.
| | - Jennifer E Hardingham
- Molecular Oncology, Basil Hetzel Institute, The Queen Elizabeth Hospital & Discipline of Physiology, School of Medicine, University of Adelaide, Adelaide, SA 5000, Australia.
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22
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Drąg J, Goździalska A, Knapik-Czajka M, Gawędzka A, Gawlik K, Jaśkiewicz J. Effect of high carbohydrate diet on elongase and desaturase activity and accompanying gene expression in rat's liver. GENES AND NUTRITION 2017; 12:2. [PMID: 28138346 PMCID: PMC5264288 DOI: 10.1186/s12263-017-0551-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 10/14/2016] [Indexed: 01/15/2023]
Abstract
Background Hepatic fatty acids (FAs) are modified through different metabolic pathways including elongation and desaturation. These processes are catalyzed by elongases and desaturases, respectively. Glucose, by transcription factors, regulates these processes. The aim of the study was to evaluate the influence of high carbohydrate diet (68%) on the expression of elongase (Elovl-2, Elovl-5, and Elovl-6) and desaturase (∆5D, ∆6D, Scd 1, Scd 2) genes and the activity of the enzymes. The changes in serum lipid profile (triglycerides (TG), total cholesterol (TC), HDL cholesterol) and glucose concentration were measured. Male Wistar rats were randomized into two study groups: animals fed with high carbohydrate diet (n = 6; HiCHO) and a control group fed with a standard diet (n = 6; ST). The expression of mRNA was determinate using reverse transcription PCR (RT-PCR). Hepatic FA composition was determined by gas chromatography, and FA ratios were used to estimate the activity of enzymes. Serum lipid profile and glucose concentration were measured using spectrophotometric methods. Results The mean values of transcript expression of all examined elongases and desaturases in liver HiCHO rats were higher as compared to ST. Higher expression did not always correspond to higher activity (as index). More monounsaturated FAs (MUFAs) were detected in the liver of HiCHO rats as compared to ST. Serum TG level was higher in the HiCHO than in ST. Conclusions These studies support the notion that the regulation of both Elovl and desaturase expression may play an important role in managing hepatic lipid composition in response to changes in dietary status.
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Affiliation(s)
- Jagoda Drąg
- Department of Analytical Biochemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Krakow, Poland.,Andrzej Frycz Modrzewski Krakow University, 1 G. Herlinga-Grudzińskiego St., 30-705 Krakow, Poland
| | - Anna Goździalska
- Faculty of Health and Medical Sciences, Andrzej Frycz Modrzewski Krakow University, Krakow, Poland
| | - Małgorzata Knapik-Czajka
- Department of Analytical Biochemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Krakow, Poland
| | - Anna Gawędzka
- Department of Analytical Biochemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Krakow, Poland
| | - Katarzyna Gawlik
- Department of Diagnostics, Chair of Clinical Biochemistry, Jagiellonian University Medical College, Krakow, Poland
| | - Jerzy Jaśkiewicz
- Faculty of Health and Medical Sciences, Andrzej Frycz Modrzewski Krakow University, Krakow, Poland
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23
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Chen Z. Progress and prospects of long noncoding RNAs in lipid homeostasis. Mol Metab 2015; 5:164-170. [PMID: 26977388 PMCID: PMC4770261 DOI: 10.1016/j.molmet.2015.12.003] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2015] [Revised: 12/10/2015] [Accepted: 12/20/2015] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Long noncoding RNAs (lncRNAs) are a novel group of universally present, non-coding RNAs (>200 nt) that are increasingly recognized as key regulators of many physiological and pathological processes. SCOPE OF REVIEW Recent publications have shown that lncRNAs influence lipid homeostasis by controlling lipid metabolism in the liver and by regulating adipogenesis. lncRNAs control lipid metabolism-related gene expression by either base-pairing with RNA and DNA or by binding to proteins. MAJOR CONCLUSIONS The recent advances and future prospects in understanding the roles of lncRNAs in lipid homeostasis are discussed.
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Affiliation(s)
- Zheng Chen
- School of Life Sciences, Northeast Normal University, Changchun, Jilin 130024, China.
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24
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Mellor CL, Steinmetz FP, Cronin MTD. The identification of nuclear receptors associated with hepatic steatosis to develop and extend adverse outcome pathways. Crit Rev Toxicol 2015; 46:138-52. [PMID: 26451809 DOI: 10.3109/10408444.2015.1089471] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The development of adverse outcome pathways (AOPs) is becoming a key component of twenty-first century toxicology. AOPs provide a conceptual framework that links the molecular initiating event to an adverse outcome through organized toxicological knowledge, bridging the gap from chemistry to toxicological effect. As nuclear receptors (NRs) play essential roles for many physiological processes within the body, they are used regularly as drug targets for therapies to treat many diseases including diabetes, cancer and neurodegenerative diseases. Due to the heightened development of NR ligands, there is increased need for the identification of related AOPs to facilitate their risk assessment. Many NR ligands have been linked specifically to steatosis. This article reviews and summarizes the role of NR and their importance with links between NR examined to identify plausible putative AOPs. The following NRs are shown to induce hepatic steatosis upon ligand binding: aryl hydrocarbon receptor, constitutive androstane receptor, oestrogen receptor, glucocorticoid receptor, farnesoid X receptor, liver X receptor, peroxisome proliferator-activated receptor, pregnane X receptor and the retinoic acid receptor. A preliminary, putative AOP was formed for NR binding linked to hepatic steatosis as the adverse outcome.
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Affiliation(s)
- Claire L Mellor
- a School of Pharmacy and Biomolecular Sciences , Liverpool John Moores University , Liverpool , England
| | - Fabian P Steinmetz
- a School of Pharmacy and Biomolecular Sciences , Liverpool John Moores University , Liverpool , England
| | - Mark T D Cronin
- a School of Pharmacy and Biomolecular Sciences , Liverpool John Moores University , Liverpool , England
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25
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He J, Dong L, Xu W, Bai K, Lu C, Wu Y, Huang Q, Zhang L, Wang T. Dietary Tributyrin Supplementation Attenuates Insulin Resistance and Abnormal Lipid Metabolism in Suckling Piglets with Intrauterine Growth Retardation. PLoS One 2015; 10:e0136848. [PMID: 26317832 PMCID: PMC4552672 DOI: 10.1371/journal.pone.0136848] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2015] [Accepted: 08/10/2015] [Indexed: 01/01/2023] Open
Abstract
Intrauterine growth retardation (IUGR) is associated with insulin resistance and lipid disorder. Tributyrin (TB), a pro-drug of butyrate, can attenuate dysfunctions in body metabolism. In this study, we investigated the effects of TB supplementation on insulin resistance and lipid metabolism in neonatal piglets with IUGR. Eight neonatal piglets with normal birth weight (NBW) and 16 neonatal piglets with IUGR were selected, weaned on the 7th day, and fed basic milk diets (NBW and IUGR groups) or basic milk diets supplemented with 0.1% tributyrin (IT group, IUGR piglets) until day 21 (n = 8). Relative parameters for lipid metabolism and mRNA expression were measured. Piglets with IUGR showed higher (P < 0.05) concentrations of insulin in the serum, higher (P < 0.05) HOMA-IR and total cholesterol, triglycerides (TG), non-esterified fatty acid (NEFA) in the liver, and lower (P < 0.05) enzyme activities (hepatic lipase [HL], lipoprotein lipase [LPL], total lipase [TL]) and concentration of glycogen in the liver than the NBW group. TB supplementation decreased (P < 0.05) the concentrations of insulin, HOMA-IR, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol in the serum, and the concentrations of TG and NEFA in the liver, and increased (P < 0.05) enzyme activities (HL, LPL, and TL) and concentration of glycogen in the liver of the IT group. The mRNA expression for insulin signal transduction pathway and hepatic lipogenic pathway (including transcription factors and nuclear factors) was significantly (P < 0.05) affected in the liver by IUGR, which was efficiently (P < 0.05) attenuated by diets supplemented with TB. TB supplementation has therapeutic potential for attenuating insulin resistance and abnormal lipid metabolism in IUGR piglets by increasing enzyme activities and upregulating mRNA expression, leading to an early improvement in the metabolic efficiency of IUGR piglets.
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Affiliation(s)
- Jintian He
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, People’s Republic of China
| | - Li Dong
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, People’s Republic of China
| | - Wen Xu
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, People’s Republic of China
| | - Kaiwen Bai
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, People’s Republic of China
| | - Changhui Lu
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, People’s Republic of China
| | - Yanan Wu
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, People’s Republic of China
| | - Qiang Huang
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, People’s Republic of China
| | - Lili Zhang
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, People’s Republic of China
| | - Tian Wang
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, People’s Republic of China
- * E-mail:
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26
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Abstract
The glucose transporter isoform GLUT2 is expressed in liver, intestine, kidney and pancreatic islet beta cells, as well as in the central nervous system, in neurons, astrocytes and tanycytes. Physiological studies of genetically modified mice have revealed a role for GLUT2 in several regulatory mechanisms. In pancreatic beta cells, GLUT2 is required for glucose-stimulated insulin secretion. In hepatocytes, suppression of GLUT2 expression revealed the existence of an unsuspected glucose output pathway that may depend on a membrane traffic-dependent mechanism. GLUT2 expression is nevertheless required for the physiological control of glucose-sensitive genes, and its inactivation in the liver leads to impaired glucose-stimulated insulin secretion, revealing a liver-beta cell axis, which is likely to be dependent on bile acids controlling beta cell secretion capacity. In the nervous system, GLUT2-dependent glucose sensing controls feeding, thermoregulation and pancreatic islet cell mass and function, as well as sympathetic and parasympathetic activities. Electrophysiological and optogenetic techniques established that Glut2 (also known as Slc2a2)-expressing neurons of the nucleus tractus solitarius can be activated by hypoglycaemia to stimulate glucagon secretion. In humans, inactivating mutations in GLUT2 cause Fanconi-Bickel syndrome, which is characterised by hepatomegaly and kidney disease; defects in insulin secretion are rare in adult patients, but GLUT2 mutations cause transient neonatal diabetes. Genome-wide association studies have reported that GLUT2 variants increase the risks of fasting hyperglycaemia, transition to type 2 diabetes, hypercholesterolaemia and cardiovascular diseases. Individuals with a missense mutation in GLUT2 show preference for sugar-containing foods. We will discuss how studies in mice help interpret the role of GLUT2 in human physiology.
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Affiliation(s)
- Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, Genopode Building, 1015, Lausanne, Switzerland,
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27
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Bertrand C, Pignalosa A, Wanecq E, Rancoule C, Batut A, Deleruyelle S, Lionetti L, Valet P, Castan-Laurell I. Effects of dietary eicosapentaenoic acid (EPA) supplementation in high-fat fed mice on lipid metabolism and apelin/APJ system in skeletal muscle. PLoS One 2013; 8:e78874. [PMID: 24244380 PMCID: PMC3820669 DOI: 10.1371/journal.pone.0078874] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 09/16/2013] [Indexed: 01/04/2023] Open
Abstract
Various studies have shown that eicosapentaenoic acid (EPA) has beneficial effects on obesity and associated disorders. Apelin, the ligand of APJ receptor also exerts insulin-sensitizing effects especially by improving muscle metabolism. EPA has been shown to increase apelin production in adipose tissue but its effects in muscle have not been addressed. Thus, the effects of EPA supplementation (36 g/kg EPA) in high-fat diet (HFD) (45% fat, 20% protein, 35% carbohydrate) were studied in mice with focus on muscle lipid metabolism and apelin/APJ expression. Compared with HFD mice, HFD+EPA mice had significantly less weight gain, fat mass, lower blood glucose, insulinemia and hepatic steatosis after 10 weeks of diet. In addition, EPA prevented muscle metabolism alterations since intramuscular triglycerides were decreased and β-oxidation increased. In soleus muscles of HFD+EPA mice, apelin and APJ expression were significantly increased compared to HFD mice. However, plasma apelin concentrations in HFD and HFD+EPA mice were similar. EPA-induced apelin expression was confirmed in differentiated C2C12 myocytes but in this model, apelin secretion was also increased in response to EPA treatment. In conclusion, EPA supplementation in HFD prevents obesity and metabolic alterations in mice, especially in skeletal muscle. Since EPA increases apelin/APJ expression in muscle, apelin may act in a paracrine/autocrine manner to contribute to these benefical effects.
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Affiliation(s)
- Chantal Bertrand
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1048, Toulouse, Cedex 4, France
- Université de Toulouse, UPS, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | | | - Estelle Wanecq
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1048, Toulouse, Cedex 4, France
- Université de Toulouse, UPS, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - Chloé Rancoule
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1048, Toulouse, Cedex 4, France
- Université de Toulouse, UPS, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - Aurélie Batut
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1048, Toulouse, Cedex 4, France
- Université de Toulouse, UPS, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - Simon Deleruyelle
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1048, Toulouse, Cedex 4, France
- Université de Toulouse, UPS, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | | | - Philippe Valet
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1048, Toulouse, Cedex 4, France
- Université de Toulouse, UPS, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - Isabelle Castan-Laurell
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1048, Toulouse, Cedex 4, France
- Université de Toulouse, UPS, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
- * E-mail:
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28
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Ye D, Tanthanuch W, Thumanu K, Sangmalee A, Parnpai R, Heraud P. Discrimination of functional hepatocytes derived from mesenchymal stem cells using FTIR microspectroscopy. Analyst 2013; 137:4774-84. [PMID: 22946081 DOI: 10.1039/c2an35329f] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Functional hepatocytes differentiated in vitro from mesenchymal stem cells (MSCs) need to be fully characterized before they could be applied as a therapy to treat liver disease. Here, we employed Fourier Transform Infrared (FTIR) microspectroscopy to investigate the characteristics of hepatocyte-like cells derived from rat bone marrow mesenchymal stem cells (rBM-MSCs) by detecting changes in macromolecular composition occurring during the hepatogenesis process. Partial Least Squares Discriminant Analysis (PLS-DA) enabled us to discriminate undifferentiated rBM-MSCs, and early, mid-stage and late stage rBM-MSCs derived hepatocytes by their characteristic FTIR "spectroscopic signatures". The predominant spectroscopic changes responsible for this discrimination were changes in FTIR absorbance bands at: 3012 cm(-1) (cis C[double bond, length as m-dash]C stretch from unsaturated lipids), 2952 cm(-1) (ν(as)CH(3) from lipids), 2854 cm(-1) (ν(s)CH(2) from lipids) and 1722 cm(-1) (C[double bond, length as m-dash]O stretching from lipids), which were associated with triglyceride and unsaturated fatty acid accumulation in the hepatocyte-like cells occurring during differentiation. Based on these findings, rBM-MSCs derived hepatocytes are characterized by high lipid content which facilitates a means of identifying hepatocytes from their stem cells progenitors by using FTIR microspectroscopy. Other complex changes in spectral bands assigned to proteins and nucleic acids were observed during hepatocyte differentiation indicating that mRNA translation was taking place producing proteins related to the formation of the new hepatocyte-like phenotype, which was corroborated by immunohistochemistry. The results show FTIR microspectroscopy combined with bioinformatic modeling constitutes a powerful new phenotypic-based methodology for monitoring and characterization of the process of stem cell differentiation leading to the formation of hepatocytes, providing complementary information to existing methodologies such as immunohistochemistry and gene analysis, but having advantages of being reagent-free and non-destructive of the sample.
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Affiliation(s)
- Danna Ye
- Embryo Technology and Stem Cell Research Center, School of Biotechnology, Suranaree University of Technology, Nakhon Ratchasima, Thailand
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29
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Kamalam BS, Medale F, Kaushik S, Polakof S, Skiba-Cassy S, Panserat S. Regulation of metabolism by dietary carbohydrates in two lines of rainbow trout divergently selected for muscle fat content. ACTA ACUST UNITED AC 2012; 215:2567-78. [PMID: 22786633 DOI: 10.1242/jeb.070581] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Previous studies in two rainbow trout lines divergently selected for lean (L) or fat (F) muscle suggested that they differ in their ability to metabolise glucose. In this context, we investigated whether genetic selection for high muscle fat content led to a better capacity to metabolise dietary carbohydrates. Juvenile trout from the two lines were fed diets with or without gelatinised starch (17.1%) for 10 weeks, after which blood, liver, muscle and adipose tissues were sampled. Growth rate, feed efficiency and protein utilisation were lower in the F line than in the L line. In both lines, intake of carbohydrates was associated with a moderate post-prandial hyperglycaemia, a protein sparing effect, an enhancement of nutrient (TOR-S6) signalling cascade and a decrease of energy-sensing enzyme (AMPK). Gene expression of hepatic glycolytic enzymes was higher in the F line fed carbohydrates compared with the L line, but concurrently transcripts for the gluconeogenic enzymes was also higher in the F line, possibly impairing glucose homeostasis. However, the F line showed a higher gene expression of hepatic enzymes involved in lipogenesis and fatty acid bioconversion, in particular with an increased dietary carbohydrate intake. Enhanced lipogenic potential coupled with higher liver glycogen content in the F line suggests better glucose storage ability than the L line. Overall, the present study demonstrates the changes in hepatic intermediary metabolism resulting from genetic selection for high muscle fat content and dietary carbohydrate intake without, however, any interaction for an improved growth or glucose utilisation in the peripheral tissues.
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Affiliation(s)
- Biju Sam Kamalam
- Institut National de la Recherche Agronomique (INRA), Nutrition, Metabolism and Aquaculture Unit (UR1067), F-64310 Saint-Pée-sur-Nivelle, France
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30
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Ma X, Lin Y, Lin L, Qin G, Pereira FA, Haymond MW, Butte NF, Sun Y. Ablation of ghrelin receptor in leptin-deficient ob/ob mice has paradoxical effects on glucose homeostasis when compared with ablation of ghrelin in ob/ob mice. Am J Physiol Endocrinol Metab 2012; 303:E422-31. [PMID: 22669248 PMCID: PMC3423126 DOI: 10.1152/ajpendo.00576.2011] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The orexigenic hormone ghrelin is important in diabetes because it has an inhibitory effect on insulin secretion. Ghrelin ablation in leptin-deficient ob/ob (Ghrelin(-/-):ob/ob) mice increases insulin secretion and improves hyperglycemia. The physiologically relevant ghrelin receptor is the growth hormone secretagogue receptor (GHS-R), and GHS-R antagonists are thought to be an effective strategy for treating diabetes. However, since some of ghrelin's effects are independent of GHS-R, we have utilized genetic approaches to determine whether ghrelin's effect on insulin secretion is mediated through GHS-R and whether GHS-R antagonism indeed inhibits insulin secretion. We investigated the effects of GHS-R on glucose homeostasis in Ghsr-ablated ob/ob mice (Ghsr(-/-):ob/ob). Ghsr ablation did not rescue the hyperphagia, obesity, or insulin resistance of ob/ob mice. Surprisingly, Ghsr ablation worsened the hyperglycemia, decreased insulin, and impaired glucose tolerance. Consistently, Ghsr ablation in ob/ob mice upregulated negative β-cell regulators (such as UCP-2, SREBP-1c, ChREBP, and MIF-1) and downregulated positive β-cell regulators (such as HIF-1α, FGF-21, and PDX-1) in whole pancreas; this suggests that Ghsr ablation impairs pancreatic β-cell function in leptin deficiency. Of note, Ghsr ablation in ob/ob mice did not affect the islet size; the average islet size of Ghsr(-/-):ob/ob mice is similar to that of ob/ob mice. In summary, because Ghsr ablation in leptin deficiency impairs insulin secretion and worsens hyperglycemia, this suggests that GHS-R antagonists may actually aggravate diabetes under certain conditions. The paradoxical effects of ghrelin ablation and Ghsr ablation in ob/ob mice highlight the complexity of the ghrelin-signaling pathway.
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Affiliation(s)
- Xiaojun Ma
- US Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
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31
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Diaz-Moralli S, Ramos-Montoya A, Marin S, Fernandez-Alvarez A, Casado M, Cascante M. Target metabolomics revealed complementary roles of hexose- and pentose-phosphates in the regulation of carbohydrate-dependent gene expression. Am J Physiol Endocrinol Metab 2012; 303:E234-42. [PMID: 22569070 DOI: 10.1152/ajpendo.00675.2011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Carbohydrate response element-binding protein (ChREBP) is a transcription factor that mediates glucose signaling in mammalian liver, leading to the expression of different glycolytic and lipogenic genes, such as pyruvate kinase (L-PK) and fatty acid synthase (FAS). The current model for ChREBP activation in response to sugar phosphates holds that glucose metabolization to xylulose 5-phosphate (X-5-P) triggers the activation of protein phosphatase 2A, which dephosphorylates ChREBP and leads to its nuclear translocation and activation. However, evidence indicates that glucose 6-phosphate (G-6-P) is the most likely signal metabolite for the glucose-induced transcription of these genes. The glucose derivative that is responsible for carbohydrate-dependent gene expression remains to be identified. The difficulties in measuring G-6-P and X-5-P concentrations simultaneously and in changing them independently have hindered such identification. To discriminate between these possibilities, we adapted a liquid chromatography mass spectrometry method to identify and quantify sugar phosphates in human hepatocarcinoma cells (Hep G2) and rat hepatocytes in response to different carbon sources and in the presence/absence of a glucose-6-phosphate dehydrogenase inhibitor. We also used this method to demonstrate that these cells could not metabolize 2-deoxyglucose beyond 2-deoxyglucose-6-phosphate. The simultaneous quantification of sugar phosphates and FAS and L-PK expression levels demonstrated that both X-5-P and G-6-P play a role in the modulation of gene expression. In conclusion, this report presents for the first time a single mechanism that incorporates the effects of X-5-P and G-6-P on the enhancement of the expression of carbohydrate-responsive genes.
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Affiliation(s)
- Santiago Diaz-Moralli
- Faculty of Biology, Department of Biochemistry and Molecular Biology, Universitat de Barcelona, Barcelona, Spain
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32
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Mori T, Kondo H, Hase T, Murase T. Dietary phospholipids ameliorate fructose-induced hepatic lipid and metabolic abnormalities in rats. J Nutr 2011; 141:2003-9. [PMID: 21940513 DOI: 10.3945/jn.111.143602] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Overconsumption of fructose results in hepatic dyslipidemia, which has a documented correlation with metabolic syndrome. We examined whether the ingestion of phospholipids (PL) from soybeans prevents fructose-induced metabolic abnormalities. Rats were fed either a fructose-free diet (C), a 60% fructose diet (F), or a 60% fructose plus 3% PL diet (F-PL) for 10 wk. At wk 8, plasma glucose concentrations after glucose loading were significantly higher in rats fed the F diet than in rats fed the C and F-PL diets, which did not differ from one another. The concentrations of hepatic TG, diglycerides, ceramides, and oleates in rats fed the F diet for 10 wk was significantly higher than those in rats fed the C diet. The increases were prevented by concurrent PL ingestion; concentrations did not differ between the F-PL and C groups. Dietary fructose increased the mRNA expression of SREBP1, ChREBP, and genes related to lipogenesis. PL completely inhibited these increases. Furthermore, reflecting the difference at the mRNA level, lipogenic enzyme activities were greater in rats fed the F diet than in rats fed the C diet, and PL ingestion suppressed the increased activities by fructose feeding. Treatment of cultured Hep-G2 cells with fructose for 24 h increased the levels of SREBP1 and ChREBP nuclear proteins, which were suppressed by culture with purified PL components, especially phosphatidylethanolamine and phosphatidylinositol. These findings indicate that PL prevents fructose-induced metabolic abnormalities in association with alterations of the hepatic lipid profile by inhibiting de novo lipogenesis.
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Affiliation(s)
- Takuya Mori
- Biological Science Laboratories, Kao Corporation, Tochigi, Japan
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33
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Pachikian BD, Essaghir A, Demoulin JB, Neyrinck AM, Catry E, De Backer FC, Dejeans N, Dewulf EM, Sohet FM, Portois L, Deldicque L, Molendi-Coste O, Leclercq IA, Francaux M, Carpentier YA, Foufelle F, Muccioli GG, Cani PD, Delzenne NM. Hepatic n-3 polyunsaturated fatty acid depletion promotes steatosis and insulin resistance in mice: genomic analysis of cellular targets. PLoS One 2011; 6:e23365. [PMID: 21853118 PMCID: PMC3154437 DOI: 10.1371/journal.pone.0023365] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Accepted: 07/13/2011] [Indexed: 12/17/2022] Open
Abstract
Patients with non-alcoholic fatty liver disease are characterised by a decreased n-3/n-6 polyunsaturated fatty acid (PUFA) ratio in hepatic phospholipids. The metabolic consequences of n-3 PUFA depletion in the liver are poorly understood. We have reproduced a drastic drop in n-3 PUFA among hepatic phospholipids by feeding C57Bl/6J mice for 3 months with an n-3 PUFA depleted diet (DEF) versus a control diet (CT), which only differed in the PUFA content. DEF mice exhibited hepatic insulin resistance (assessed by euglycemic-hyperinsulinemic clamp) and steatosis that was associated with a decrease in fatty acid oxidation and occurred despite a higher capacity for triglyceride secretion. Microarray and qPCR analysis of the liver tissue revealed higher expression of all the enzymes involved in lipogenesis in DEF mice compared to CT mice, as well as increased expression and activation of sterol regulatory element binding protein-1c (SREBP-1c). Our data suggest that the activation of the liver X receptor pathway is involved in the overexpression of SREBP-1c, and this phenomenon cannot be attributed to insulin or to endoplasmic reticulum stress responses. In conclusion, n-3 PUFA depletion in liver phospholipids leads to activation of SREBP-1c and lipogenesis, which contributes to hepatic steatosis.
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Affiliation(s)
- Barbara D. Pachikian
- Metabolism and Nutrition Research Group, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Ahmed Essaghir
- De Duve Institute, Université Catholique de Louvain, Brussels, Belgium
| | | | - Audrey M. Neyrinck
- Metabolism and Nutrition Research Group, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Emilie Catry
- Metabolism and Nutrition Research Group, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Fabienne C. De Backer
- Metabolism and Nutrition Research Group, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Nicolas Dejeans
- Toxicology and Cancer Biology Research Group, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Evelyne M. Dewulf
- Metabolism and Nutrition Research Group, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Florence M. Sohet
- Metabolism and Nutrition Research Group, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Laurence Portois
- Laboratory of Experimental Surgery, Université Libre de Bruxelles, Brussels, Belgium
| | - Louise Deldicque
- Research Centre for Exercise and Health, Department of Biomedical Kinesiology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Olivier Molendi-Coste
- Laboratory of Hepato-Gastroenterology, Institut de Recherche Expérimentale et Clinique, Université Catholique de Louvain, Brussels, Belgium
| | - Isabelle A. Leclercq
- Laboratory of Hepato-Gastroenterology, Institut de Recherche Expérimentale et Clinique, Université Catholique de Louvain, Brussels, Belgium
| | - Marc Francaux
- Research Group in Muscle and Exercise Physiology, Institute of Neuroscience, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Yvon A. Carpentier
- Laboratory of Experimental Surgery, Université Libre de Bruxelles, Brussels, Belgium
| | - Fabienne Foufelle
- INSERM, UMR-S 872, Centre de Recherche des Cordeliers, Paris, France
| | - Giulio G. Muccioli
- Bioanalysis and Pharmacology of Bioactive Lipids lab, CHAM7230, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Patrice D. Cani
- Metabolism and Nutrition Research Group, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Nathalie M. Delzenne
- Metabolism and Nutrition Research Group, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium
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34
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Higuchi N, Kato M, Miyazaki M, Tanaka M, Kohjima M, Ito T, Nakamuta M, Enjoji M, Kotoh K, Takayanagi R. Potential role of branched-chain amino acids in glucose metabolism through the accelerated induction of the glucose-sensing apparatus in the liver. J Cell Biochem 2011; 112:30-8. [PMID: 20506195 DOI: 10.1002/jcb.22688] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Branched-chain amino acids (BCAAs) have a potential to improve glucose metabolism in cirrhotic patients; however, the contribution of liver in this process has not been clarified. To estimate the effect of BCAA on glucose metabolism in liver, we evaluated the mRNA expression levels of glucose-sensing apparatus genes in HepG2 cells and in rat liver after oral administration of BCAA. HepG2 cells were cultured in low glucose (100 mg/dl) or high glucose (400 mg/dl) in the absence or presence of BCAA. The mRNA expression levels and protein levels of GLUT2 and liver-type glucokinase (L-GK) were estimated using RT-PCR and immunoblotting. The expression levels of transcriptional factors, including SREBP-1c, ChREBP, PPAR-γm and LXRα, were estimated. The mRNA expression levels of transcriptional factors, glycogen synthase, and genes involved in gluconeogenesis were evaluated in rat liver at 3 h after the administration of BCAA. BCAA accelerated the expression of GLUT2 and L-GK in HepG2 cells in high glucose. Expression levels of ChREBP, SREBP-1c, and LXRα were also increased in this condition. BCAA administration enhanced the mRNA expression levels of L-GK, SREBP-1c, and LXRα and suppressed the expression levels of G-6-Pase in rat liver, without affecting the expression levels of glycogen synthase or serum glucose concentrations. BCAA administration enhanced the bioactivity of the glucose-sensing apparatus, probably via the activation of a transcriptional mechanism, suggesting that these amino acids may improve glucose metabolism through the accelerated utility of glucose and glucose-6-phosphate in the liver.
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Affiliation(s)
- Nobito Higuchi
- Department of Medicine and Bioregulatory Science, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan
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Burri L, Berge K, Wibrand K, Berge RK, Barger JL. Differential effects of krill oil and fish oil on the hepatic transcriptome in mice. Front Genet 2011; 2:45. [PMID: 22303341 PMCID: PMC3268598 DOI: 10.3389/fgene.2011.00045] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Accepted: 06/25/2011] [Indexed: 12/14/2022] Open
Abstract
Dietary supplementation with ω-3 polyunsaturated fatty acids (ω-3 PUFAs), specifically the fatty acids docosahexaenoic acid (DHA; 22:6 ω-3) and eicosapentaenoic acid (EPA; 20:5 ω-3), is known to have beneficial health effects including improvements in glucose and lipid homeostasis and modulation of inflammation. To evaluate the efficacy of two different sources of ω-3 PUFAs, we performed gene expression profiling in the liver of mice fed diets supplemented with either fish oil (FO) or krill oil (KO). We found that ω-3 PUFA supplements derived from a phospholipid krill fraction (KO) downregulated the activity of pathways involved in hepatic glucose production as well as lipid and cholesterol synthesis. The data also suggested that KO-supplementation increases the activity of the mitochondrial respiratory chain. Surprisingly, an equimolar dose of EPA and DHA derived from FO modulated fewer pathways than a KO-supplemented diet and did not modulate key metabolic pathways regulated by KO, including glucose metabolism, lipid metabolism and the mitochondrial respiratory chain. Moreover, FO upregulated the cholesterol synthesis pathway, which was the opposite effect of krill-supplementation. Neither diet elicited changes in plasma levels of lipids, glucose, or insulin, probably because the mice used in this study were young and were fed a low-fat diet. Further studies of KO-supplementation using animal models of metabolic disorders and/or diets with a higher level of fat may be required to observe these effects.
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Kim E, Liu NC, Yu IC, Lin HY, Lee YF, Sparks JD, Chen LM, Chang C. Metformin inhibits nuclear receptor TR4-mediated hepatic stearoyl-CoA desaturase 1 gene expression with altered insulin sensitivity. Diabetes 2011; 60:1493-503. [PMID: 21478464 PMCID: PMC3292323 DOI: 10.2337/db10-0393] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
OBJECTIVE TR4 is a nuclear receptor without clear pathophysiological roles. We investigated the roles of hepatic TR4 in the regulation of lipogenesis and insulin sensitivity in vivo and in vitro. RESEARCH DESIGN AND METHODS TR4 activity and phosphorylation assays were carried out using hepatocytes and various TR4 wild-type and mutant constructs. Liver tissues from TR4 knockout, C57BL/6, and db/db mice were examined to investigate TR4 target gene stearoyl-CoA desaturase (SCD) 1 regulation. RESULTS TR4 transactivation is inhibited via phosphorylation by metformin-induced AMP-activated protein kinase (AMPK) at the amino acid serine 351, which results in the suppression of SCD1 gene expression. Additional mechanistic dissection finds TR4-transactivated SCD1 promoter activity via direct binding to the TR4-responsive element located at -243 to -255 on the promoter region. The pathophysiological consequences of the metformin→AMPK→TR4→SCD1 pathway are examined via TR4 knockout mice and primary hepatocytes with either knockdown or overexpression of TR4. The results show that the suppression of SCD1 via loss of TR4 resulted in reduced fat mass and increased insulin sensitivity with increased β-oxidation and decreased lipogenic gene expression. CONCLUSIONS The pathway from metformin→AMPK→TR4→SCD1→insulin sensitivity suggests that TR4 may function as an important modulator to control lipid metabolism, which sheds light on the use of small molecules to modulate TR4 activity as a new alternative approach to battle the metabolic syndrome.
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Affiliation(s)
- Eungseok Kim
- Departments of Pathology and Urology and the Wilmot Cancer Center, University of Rochester Medical Center, Rochester, New York
- Department of Biological Sciences, Chonnam National University, Gwangju, Korea
| | - Ning-Chun Liu
- Departments of Pathology and Urology and the Wilmot Cancer Center, University of Rochester Medical Center, Rochester, New York
| | - I-Chen Yu
- Departments of Pathology and Urology and the Wilmot Cancer Center, University of Rochester Medical Center, Rochester, New York
| | - Hung-Yun Lin
- Departments of Pathology and Urology and the Wilmot Cancer Center, University of Rochester Medical Center, Rochester, New York
| | - Yi-Fen Lee
- Departments of Pathology and Urology and the Wilmot Cancer Center, University of Rochester Medical Center, Rochester, New York
| | - Janet D. Sparks
- Departments of Pathology and Urology and the Wilmot Cancer Center, University of Rochester Medical Center, Rochester, New York
| | - Lu-Min Chen
- Departments of Pathology and Urology and the Wilmot Cancer Center, University of Rochester Medical Center, Rochester, New York
- Sex Hormone Research Center, China Medical University/Hospital, Taichung, Taiwan
| | - Chawnshang Chang
- Departments of Pathology and Urology and the Wilmot Cancer Center, University of Rochester Medical Center, Rochester, New York
- Sex Hormone Research Center, China Medical University/Hospital, Taichung, Taiwan
- Corresponding author: Chawnshang Chang,
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Samuel VT. Fructose induced lipogenesis: from sugar to fat to insulin resistance. Trends Endocrinol Metab 2011; 22:60-5. [PMID: 21067942 DOI: 10.1016/j.tem.2010.10.003] [Citation(s) in RCA: 179] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Revised: 10/13/2010] [Accepted: 10/13/2010] [Indexed: 12/23/2022]
Abstract
Increasing consumption of sugars is one of the contributing factors to the obesity epidemic. Both cane sugar and high-fructose corn syrup contain glucose and fructose. Fructose, in contrast to glucose, is known to potently stimulate lipogenesis, but the mechanisms responsible are not yet fully known. This paper reviews several possible pathways that might be involved, such as activation of pyruvate dehydrogenase, and transcriptional activation of sterol regulatory element binding protein 1c by key regulators such as peroxisome proliferator activated receptor-γ co-activator 1β and the splice variant of X-box binding protein 1. Together, these pathways might establish a feed forward cycle that can rapidly increase hepatic lipogenesis. As a result, dietary fructose might promote the development of nonalcoholic fatty liver disease, which in and of itself, can result in hepatic insulin resistance, a key feature of type 2 diabetes mellitus.
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Affiliation(s)
- Varman T Samuel
- Departments of Internal Medicine, Yale University School of Medicine, New Haven, CT 06536-8012, USA.
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Richards MP, Proszkowiec-Weglarz M, Rosebrough RW, McMurtry JP, Angel R. Effects of early neonatal development and delayed feeding immediately post-hatch on the hepatic lipogenic program in broiler chicks. Comp Biochem Physiol B Biochem Mol Biol 2010; 157:374-88. [DOI: 10.1016/j.cbpb.2010.08.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Revised: 08/18/2010] [Accepted: 08/26/2010] [Indexed: 10/19/2022]
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Mochizuki K, Sato Y, Takase S, Goda T. Changes in mucosal alpha-glucosidase activities along the jejunal-ileal axis by an Hm-HACS diet intake are associated with decreased lipogenic enzyme activity in epididymal adipose tissue. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2010; 58:6923-6927. [PMID: 20481469 DOI: 10.1021/jf904259d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Heat-moisture (hm)-high-amylose corn starch (HACS), which includes a larger amount of resistant starch than HACS or regular cornstarch (CS), is more indigestible in the small intestine than HACS or CS. An hm-HACS diet was also shown to ameliorate glucose intolerance and lipid abnormalities. This study examined the effects of feeding rats an hm-HACS diet for 14 days on the activities of mucosal alpha-glucosidase along the jejunal-ileal axis and lipogenic enzymes in epididymal adipose tissue. The contents in the lumen of the cecum were increased by feeding rats the HACS and hm-HACS diets, and the cecal weight was increased by the hm-HACS diet. The HACS diet reduced the activity of alpha-glucosidase in the upper jejunal mucosa, induced its activity in the upper ileal mucosa, reduced lipogenic enzyme activity in epididymal adipose tissue, and reduced serum triglyceride levels. These effects were more pronounced with the hm-HACS than with the HACS diet. These results suggest that feeding rats the hm-HACS diet reduced the activities of lipogenic enzymes in adipose tissue and alpha-glucosidase in the jejunal mucosa and induced the activity of alpha-glucosidase in the ileal mucosa compared with the HACS diet.
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Affiliation(s)
- Kazuki Mochizuki
- Laboratory of Nutritional Physiology, The University of Shizuoka Graduate School of Nutritional and Environmental Sciences and Global COE, Shizuoka-shi, Shizuoka, Japan
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Rockett BD, Salameh M, Carraway K, Morrison K, Shaikh SR. n-3 PUFA improves fatty acid composition, prevents palmitate-induced apoptosis, and differentially modifies B cell cytokine secretion in vitro and ex vivo. J Lipid Res 2010; 51:1284-97. [PMID: 20071694 DOI: 10.1194/jlr.m000851] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
n-3 polyunsaturated fatty acids (PUFAs) modify T-cell activation, in part by remodeling lipid composition; however, the relationship between n-3 PUFA and B-cell activation is unknown. Here we tested this relationship in vitro and ex vivo by measuring upregulation of B-cell surface molecules, the percentage of cells activated, and cytokine secreted in response to lipopolysaccharide (LPS) activation. In vitro, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) improved the membrane n-6/n-3 PUFA ratio, and DHA lowered interleukin (IL)-6 secretion; overall, n-3 PUFAs did not suppress B-cell activation compared with BSA, oleate, or elaidate treatment. Palmitate treatment suppressed the percentage of B cells activated through lipoapoptosis, which was differentially prevented by cosupplementing cells with MUFAs and PUFAs. Ex vivo, we tested the hypothesis with mice fed a control or high-fat saturated, hydrogenated, MUFA or n-3 PUFA diets. n-3 PUFAs had no effect on the percentage of B cells activated. Unexpectedly, the n-3 PUFA diet increased B-cell CD69 surface expression, IL-6 and IFNgamma secretion, and it significantly increased body weight gain. Overall, we propose that changes in lipid composition with n-3 PUFA and suppression of lymphocyte activation is not universal. The study highlights that high-fat n-3 PUFA diets can promote pro-inflammatory responses, at least from one cell type.
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Affiliation(s)
- Benjamin Drew Rockett
- Department of Biochemistry and Molecular Biology, East Carolina Diabetes and Obesity Institute, Brody School of Medicine, East Carolina University, 600 Moye Blvd, Brody 5S-18, Greenville, NC 27834, USA
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Skiba-Cassy S, Lansard M, Panserat S, Médale F. Rainbow trout genetically selected for greater muscle fat content display increased activation of liver TOR signaling and lipogenic gene expression. Am J Physiol Regul Integr Comp Physiol 2009; 297:R1421-9. [PMID: 19710390 DOI: 10.1152/ajpregu.00312.2009] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Genetic selection is commonly used in farm animals to manage body fat content. In rainbow trout, divergent selection for low or high muscle fat content leads to differences in utilization of dietary energy sources between the fat muscle line (FL) and the lean muscle line (LL). To establish whether genetic selection on muscle fat content affects the hepatic insulin/nutrient signaling pathway, we analyzed this pathway and the expression of several metabolism-related target genes in the livers of the two divergent lines under fasting and then refeeding conditions. Whereas glycemia returned to basal level 24 h after refeeding in FL trout, it remained elevated in the LL trout. Target of rapamycin (TOR) protein was more abundant in the livers of FL trout than in LL trout, and refeeding activation of the hepatic TOR signaling pathway (TOR, S6K1, and S6) was therefore enhanced. Genes related to glycolysis (glucokinase and pyruvate kinase) and gluconeogenesis (glucose-6-phosphatase and phosphoenolpyruvate carboxykinase) were only slightly affected by refeeding and genetic selection. Refeeding stimulated expression of lipogenic genes and the sterol-responsive element binding protein (SREBP1), and expression of fatty acid synthase, glucose-6-phosphate dehydrogenase, and serine dehydratase was predominant in the livers of FL fish compared with LL fish. In agreement with recent findings linking TOR to lipogenesis control, we concluded that genetic selection for muscle fat content resulted in overactivation of the TOR signaling pathway-associated lipogenesis and probably also improved utilization of glucose.
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Affiliation(s)
- Sandrine Skiba-Cassy
- Unité Mixte de Recherches 1067 Nutrition Aquaculture and Génomique, Institut National de la Recherche Agronomique, Pôle d'hydrobiologie, 64310 Saint Pée-sur-Nivelle, France.
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Hepatic protein kinase B (Akt)-target of rapamycin (TOR)-signalling pathways and intermediary metabolism in rainbow trout (Oncorhynchus mykiss) are not significantly affected by feeding plant-based diets. Br J Nutr 2009; 102:1564-73. [PMID: 19664314 DOI: 10.1017/s000711450999095x] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The aim of the present study was to analyse the effects of partial or total replacement of fish meal (FM) and fish oil (FO) by a mixture of plant protein (PP) and a mixture of vegetable oils (VO) on the hepatic insulin-nutrient-signalling pathway and intermediary metabolism-related gene expression in rainbow trout (Oncorhynchus mykiss). Triplicate groups of fish were fed four practical diets containing graded levels of replacement of FM and FO by PP and VO for 12 weeks: diet 0/0 (100 % FM, 100 % FO); diet 50/50 (50 % FM and 50 % PP, 50 % FO and 50 % VO); diet 50/100 (50 % FM and 50 % PP, 100 % VO); diet 100/100 (100 % PP, 100 % VO). Samplings were performed on trout starved for 5 d then refed with their allocated diet. In contrast to partial substitution (diet 50/50), total substitution of FM and FO (diet 100/100) led to significantly lower growth compared with diet 0/0. The insulin-nutrient-signalling pathway (protein kinase B (Akt), target of rapamycin (TOR), S6 protein kinase 1 (S6K1) and S6) was characterised in trout liver and found to be activated by refeeding. However, changes in diet compositions did not differentially affect the Akt-TOR-signalling pathway. Moreover, expression of genes encoding fructose-1,6-biphosphatase, mitochondrial phosphoenolpyruvate carboxykinase, glucokinase, pyruvate kinase and carnitine palmitoyl transferase 1 were not affected by refeeding or by dietary changes. Refeeding down- and up-regulated the expression of gluconeogenic glucose-6-phosphatase isoform 1 and lipogenic fatty acid synthase genes, respectively. Expression of both genes was also increased with partial replacement of FM and total replacement of FO (diet 50/100). These findings indicate that plant-based diets barely affect glucose and lipid metabolism in trout.
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Sirek AS, Liu L, Naples M, Adeli K, Ng DS, Jin T. Insulin stimulates the expression of carbohydrate response element binding protein (ChREBP) by attenuating the repressive effect of Pit-1, Oct-1/Oct-2, and Unc-86 homeodomain protein octamer transcription factor-1. Endocrinology 2009; 150:3483-92. [PMID: 19359385 DOI: 10.1210/en.2008-1702] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The carbohydrate response element binding protein (ChREBP) has been recognized as a key controller of hepatic lipogenesis. Whereas the function of ChREBP has been extensively investigated, mechanisms underlying its transcription remain largely unknown, although ChREBP production is elevated in a hyperinsulinemic mouse model. We located a conserved Pit-1, Oct-1/Oct-2, and Unc-86 (POU) protein binding site (ATGCTAAT) within the proximal promoter region of human ChREBP. This site interacts with the POU homeodomain protein octamer transcription factor-1 (Oct-1), as detected by gel shift and chromatin immunoprecipitation assays. Oct-1 cotransfection in the human HepG2 cell line repressed ChREBP promoter activity approximately 50-75% (P < 0.01 to P < 0.001), and this repression was dependent on the existence of the POU binding site. Furthermore, overexpression of Oct-1 repressed endogenous ChREBP mRNA and protein expression, whereas knockdown of Oct-1 expression, using a lentivirus-based small hairpin RNA approach, led to increased ChREBP mRNA and protein expression. In contrast, HepG2 cells treated with 10 or 100 nM insulin for 4 or 8 h resulted in an approximately 2-fold increase of ChREBP promoter activity (P < 0.05 to P < 0.01). Insulin (10 nM) also stimulated endogenous ChREBP expression in HepG2 and primary hamster hepatocytes. More importantly, we found that the stimulatory effect of insulin on ChREBP promoter activity was dependent on the presence of the POU binding site, and insulin treatment reduced Oct-1 expression levels. Our observations therefore identify Oct-1 as a transcriptional repressor of ChREBP and suggest that insulin stimulates ChREBP expression via attenuating the repressive effect of Oct-1.
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Affiliation(s)
- Adam S Sirek
- Department of Physiology, University of Toronto, Toronto, Canada
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Proszkowiec-Weglarz M, Richards MP, Humphrey BD, Rosebrough RW, McMurtry JP. AMP-activated protein kinase and carbohydrate response element binding protein: a study of two potential regulatory factors in the hepatic lipogenic program of broiler chickens. Comp Biochem Physiol B Biochem Mol Biol 2009; 154:68-79. [PMID: 19427916 DOI: 10.1016/j.cbpb.2009.05.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Revised: 05/04/2009] [Accepted: 05/05/2009] [Indexed: 12/11/2022]
Abstract
This study investigated the effects of fasting and refeeding on AMP-activated protein kinase (AMPK) and carbohydrate response element binding protein (ChREBP) mRNA, protein and activity levels; as well as the expression of lipogenic genes involved in regulating lipid synthesis in broiler chicken (Gallus gallus) liver. Fasting for 24 or 48 h produced significant declines in plasma glucose (at 24 h), insulin and thyroid hormone (T3) levels that were accompanied by changes in mRNA expression levels of hepatic lipogenic genes. The mRNA levels of malic enzyme (ME), ATP-citrate lyase (ACL), acetyl-CoA carboxylase alpha (ACCalpha), fatty acid synthase (FAS), stearoyl-CoA desaturase-1 (SCD-1) and thyroid hormone responsive Spot 14 (Spot 14) declined in response to fasting. Refeeding for 24 h increased mRNA levels for each of these genes, characterized by a significant increase ('overshoot') above fed control values. No change in mRNA expression of the two AMPK alpha subunit genes was observed in response to fasting or refeeding. In contrast, ChREBP and sterol regulatory element binding protein-1 (SREBP-1) mRNA levels decreased during fasting and increased with refeeding. Phosphorylation of AMPK alpha subunits increased modestly after a 48 h fast. However, there was no corresponding change in the phosphorylation of ACC, a major downstream target of AMPK. Protein level and DNA-binding activity of ChREBP increased during fasting and declined upon refeeding as measured in whole liver tissue extracts. In general, evidence was found for coordinate transcriptional regulation of lipogenic program genes in broiler chicken liver, but specific regulatory roles for AMPK and ChREBP in that process remain to be further characterized.
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Affiliation(s)
- Monika Proszkowiec-Weglarz
- United States Department of Agriculture, Agricultural Research Service, Animal and Natural Resources Institute, Animal Biosciences and Biotechnology Laboratory, Beltsville, MD 20705-2350, USA
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Moon YA, Hammer RE, Horton JD. Deletion of ELOVL5 leads to fatty liver through activation of SREBP-1c in mice. J Lipid Res 2008; 50:412-423. [PMID: 18838740 DOI: 10.1194/jlr.m800383-jlr200] [Citation(s) in RCA: 162] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Elongation of very long chain fatty acids (ELOVL)5 is one of seven mammalian fatty acid condensing enzymes involved in microsomal fatty acid elongation. To determine the in vivo substrates and function of ELOVL5, we generated Elovl5(-/-) mice. Studies using liver microsomal protein from wild-type and knockout mice demonstrated that the elongation of gamma-linolenic (C18:3, n-6) to dihomo-gamma-linolenic (C20:3, n-6) and stearidonic (C18:4, n-3) to omega3-arachidonic acid (C20:4, n-3) required ELOVL5 activity. Tissues of Elovl5(-/-) mice accumulated the C18 substrates of ELOVL5 and the levels of the downstream products, arachidonic acid (C20:4, n-6) and docosahexaenoic acid (DHA, C22:6, n-3), were decreased. A consequence of decreased cellular arachidonic acid and DHA concentrations was the activation of sterol regulatory element-binding protein (SREBP)-1c and its target genes involved in fatty acid and triglyceride synthesis, which culminated in the development of hepatic steatosis in Elovl5(-/-) mice. The molecular and metabolic changes in fatty acid metabolism in Elovl5(-/-) mice were reversed by dietary supplementation with arachidonic acid and DHA. These studies demonstrate that reduced ELOVL5 activity leads to hepatic steatosis, and endogenously synthesized PUFAs are key regulators of SREBP-1c activation and fatty acid synthesis in livers of mice.
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Affiliation(s)
- Young-Ah Moon
- From the Department of Molecular Genetics, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-9046
| | - Robert E Hammer
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-9046
| | - Jay D Horton
- From the Department of Molecular Genetics, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-9046; Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-9046.
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Plagnes-Juan E, Lansard M, Seiliez I, Médale F, Corraze G, Kaushik S, Panserat S, Skiba-Cassy S. Insulin regulates the expression of several metabolism-related genes in the liver and primary hepatocytes of rainbow trout (Oncorhynchus mykiss). J Exp Biol 2008; 211:2510-8. [DOI: 10.1242/jeb.018374] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
SUMMARYRainbow trout have a limited ability to use dietary carbohydrates efficiently and are considered to be glucose intolerant. Administration of carbohydrates results in persistent hyperglycemia and impairs post-prandial down regulation of gluconeogenesis despite normal insulin secretion. Since gluconeogenic genes are mainly under insulin control, we put forward the hypothesis that the transcriptional function of insulin as a whole may be impaired in the trout liver. In order to test this hypothesis, we performed intraperitoneal administration of bovine insulin to fasted rainbow trout and also subjected rainbow trout primary hepatocytes to insulin and/or glucose stimulation. We demonstrate that insulin was able to activate Akt, a key element in the insulin signaling pathway, and to regulate hepatic metabolism-related target genes both in vivo and in vitro. In the same way as in mammals, insulin decreased mRNA expression of gluconeogenic genes, including glucose 6-phosphatase (G6Pase),fructose 1,6-bisphosphatase (FBPase) and phosphoenolpyruvate carboxykinase (PEPCK). Insulin also limited the expression of carnitine palmitoyltransferase 1 (CPT1), a limiting enzyme of fatty acid β-oxidation. In vitro studies revealed that, as in mammals,glucose is an important regulator of some insulin target genes such as the glycolytic enzyme pyruvate kinase (PK) and the lipogenic enzyme fatty acid synthase (FAS). Interestingly, glucose also stimulates expression of glucokinase (GK), which has no equivalent in mammals. This study demonstrates that insulin possesses the intrinsic ability to regulate hepatic gene expression in rainbow trout, suggesting that other hormonal or metabolic factors may counteract some of the post-prandial actions of insulin.
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Affiliation(s)
- Elisabeth Plagnes-Juan
- INRA, UMR 1067 Nutrition Aquaculture and Génomique, Pôle d'hydrobiologie, CD 918, F-64310 Saint Pée-sur-Nivelle, France
| | - Marine Lansard
- INRA, UMR 1067 Nutrition Aquaculture and Génomique, Pôle d'hydrobiologie, CD 918, F-64310 Saint Pée-sur-Nivelle, France
| | - Iban Seiliez
- INRA, UMR 1067 Nutrition Aquaculture and Génomique, Pôle d'hydrobiologie, CD 918, F-64310 Saint Pée-sur-Nivelle, France
| | - Françoise Médale
- INRA, UMR 1067 Nutrition Aquaculture and Génomique, Pôle d'hydrobiologie, CD 918, F-64310 Saint Pée-sur-Nivelle, France
| | - Geneviève Corraze
- INRA, UMR 1067 Nutrition Aquaculture and Génomique, Pôle d'hydrobiologie, CD 918, F-64310 Saint Pée-sur-Nivelle, France
| | - Sadasivam Kaushik
- INRA, UMR 1067 Nutrition Aquaculture and Génomique, Pôle d'hydrobiologie, CD 918, F-64310 Saint Pée-sur-Nivelle, France
| | - Stéphane Panserat
- INRA, UMR 1067 Nutrition Aquaculture and Génomique, Pôle d'hydrobiologie, CD 918, F-64310 Saint Pée-sur-Nivelle, France
| | - Sandrine Skiba-Cassy
- INRA, UMR 1067 Nutrition Aquaculture and Génomique, Pôle d'hydrobiologie, CD 918, F-64310 Saint Pée-sur-Nivelle, France
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Nguyen P, Leray V, Diez M, Serisier S, Le Bloc'h J, Siliart B, Dumon H. Liver lipid metabolism. J Anim Physiol Anim Nutr (Berl) 2008; 92:272-83. [PMID: 18477307 DOI: 10.1111/j.1439-0396.2007.00752.x] [Citation(s) in RCA: 555] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The liver plays a key role in lipid metabolism. Depending on species it is, more or less, the hub of fatty acid synthesis and lipid circulation through lipoprotein synthesis. Eventually the accumulation of lipid droplets into the hepatocytes results in hepatic steatosis, which may develop as a consequence of multiple dysfunctions such as alterations in beta-oxidation, very low density lipoprotein secretion, and pathways involved in the synthesis of fatty acids. In addition an increased circulating pool of non-esterified fatty acid may also to be a major determinant in the pathogenesis fatty liver disease. This review also focuses on transcription factors such as sterol-regulatory-element-binding protein-1c and peroxisome proliferator-activated receptor alpha, which promote either hepatic fatty acid synthesis or oxidation.
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Affiliation(s)
- P Nguyen
- Nutrition and Endocrinology Unit, National Veterinary School of Nantes, Nantes, France.
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Abstract
Nonalcoholic fatty liver disease (NAFLD) is a group of diseases with excess fat in liver in the absence of a poorly defined limit of alcohol consumption. Most common variety, a universal public health problem, is associated with insulin resistance caused by a host of genetic and epigenetic defects modulated by life style and environmental factors. In fact the term NAFLD is loose to incorporate so many etiologies except alcoholism and few other etiologies, presenting as fat in liver. However as a sign fatty liver is very important in predicting the risk of diabetes, cardiovascular disease, stroke, cirrhosis and cancer. Abnormal fat accumulation can result from several defects in nuclear receptors associated with lipid sensing, synthesis and oxidation like LXR, FXR, SREBP, ChREBP and PPAR; defects in the lipid influx-efflux channels, insulin signaling, proteins involved in fatty acid catabolism, defects in adipose tissue development and function, inappropriate nutrition and finally defects in neural regulatory mechanisms. The progress of the disease is determined by the basic defects which results in fat accumulation, an individual’s immunological response to the accumulated fat and its derivatives and the oxidant stress response. Congregation of unrelated genetic defects under same diagnosis ‘NAFLD’ can result in inefficient patient management. Further studies are required to understand the molecular basis of fatty liver to enable a personalized management of diseases presenting as fatty liver in the absence of alcohol abuse.
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